MIT Introduction to Deep Learning (6.S191) Instructors: Alexander Amini and Ava Soleimany Course Information Summary Prerequisites Schedule Lectures Labs, Final Projects, Grading, and Prizes Software labs Gather.Town lab + Office Hour sessions Final project Paper Review Project Proposal Presentation Project Proposal Grading Rubric Past Project Proposal Ideas Awards + Categories Important Links and Emails Course Information Summary MIT's introductory course on deep learning methods with applications to computer vision, natural language processing, biology, and more! Students will gain foundational knowledge of deep learning algorithms and get practical experience in building neural networks in TensorFlow. Course concludes with a project proposal competition with feedback from staff and a panel of industry sponsors. Prerequisites We expect basic knowledge of calculus (e.g., taking derivatives), linear algebra (e.g., matrix multiplication), and probability (e.g., Bayes theorem) -- we'll try to explain everything else along the way! Experience in Python is helpful but not necessary. This class is taught during MIT's IAP term by current MIT PhD researchers. Listeners are welcome! Schedule Monday Jan 18, 2021 Lecture: Introduction to Deep Learning and NNs Lab: Lab 1A Tensorflow and building NNs from scratch Tuesday Jan 19, 2021 Lecture: Deep Sequence Modelling Lab: Lab 1B Music Generation using RNNs Wednesday Jan 20, 2021 Lecture: Deep Computer Vision Lab: Lab 2A Image classification and detection Thursday Jan 21, 2021 Lecture: Deep Generative Modelling Lab: Lab 2B Debiasing facial recognition systems Friday Jan 22, 2021 Lecture: Deep Reinforcement Learning Lab: Lab 3 pixel-to-control planning Monday Jan 25, 2021 Lecture: Limitations and New Frontiers Lab: Lab 3 continued Tuesday Jan 26, 2021 Lecture (part 1): Evidential Deep Learning Lecture (part 2): Bias and Fairness Lab: Work on final assignments Lab competition entries due at 11:59pm ET on Canvas! Lab 1, Lab 2, and Lab 3 Wednesday Jan 27, 2021 Lecture (part 1): Nigel Duffy, Ernst & Young Lecture (part 2): Kate Saenko, Boston University and MIT-IBM Watson AI Lab Lab: Work on final assignments Assignments due: Sign up for Final Project Competition Thursday Jan 28, 2021 Lecture (part 1): Sanja Fidler, U. Toronto, Vector Institute, and NVIDIA Lecture (part 2): Katherine Chou, Google Lab: Work on final assignments Assignments due: 1 page paper review (if applicable) Friday Jan 29, 2021 Lecture: Student project pitch competition Lab: Awards ceremony and prize giveaway Assignments due: Project proposals (if applicable) Lectures Lectures will be held starting at 1:00pm ET from Jan 18 - Jan 29 2021, Monday through Friday, virtually through Zoom. Current MIT students, faculty, postdocs, researchers, staff, etc. will be able to access the lectures during this two week period, synchronously or asynchronously, via the MIT Canvas course webpage (MIT internal only). Lecture recordings will be uploaded to the Canvas as soon as possible; students are not required to attend any lectures synchronously. Please see the Canvas for details on Zoom links. The public edition of the course will only be made available after completion of the MIT course. Labs, Final Projects, Grading, and Prizes Course will be graded during MIT IAP for 6 units under P/D/F grading. Receiving a passing grade requires completion of each software lab project (through honor code, with submission required to enter lab competitions), a final project proposal/presentation or written review of a deep learning paper (submission required), and attendance/lecture viewing (through honor code). Submission of a written report or presentation of a project proposal will ensure a passing grade. MIT students will be eligible for prizes and awards as part of the class competitions. There will be two parts to the competitions: (1) software labs and (2) final projects. More information is provided below. Winners will be announced on the last day of class, with thousands of dollars of prizes being given away! Software labs There are three TensorFlow software lab exercises for the course, designed as iPython notebooks hosted in Google Colab. Software labs can be found on GitHub: https://github.com/aamini/introtodeeplearning. These are self-paced exercises and are designed to help you gain practical experience implementing neural networks in TensorFlow. For registered MIT students, submission of lab materials is not necessary to get credit for the course or to pass the course. At the end of each software lab there will be task-associated materials to submit (along with instructions) for entry into the competitions, open to MIT students and affiliates during the IAP offering. This includes MIT students/affiliates who are taking the class as listeners -- you are eligible! These instructions are provided at the end of each of the labs. Completing these tasks and submitting your materials to Canvas will enter you into a per-lab competition. MIT students and affiliates will be eligible for prizes during the IAP offering; at the end of the course, prize-winners will be awarded with their prizes. All competition submissions are due on January 26 at 11:59pm ET to Canvas. For the software lab competitions, submissions will be judged on the basis of the following criteria: Strength and quality of final results (lab dependent) Soundness of implementation and approach Thoroughness and quality of provided descriptions and figures Gather.Town lab + Office Hour sessions After each day’s lecture, there will be open Office Hours in the class GatherTown, up until 3pm ET. An MIT email is required to log in and join the GatherTown. During these sessions, there will not be a walk through or dictation of the labs; the labs are designed to be self-paced and to be worked on on your own time. The GatherTown sessions will be hosted by course staff and are held so you can: Ask questions on course lectures, labs, logistics, project, or anything else; Work on the labs in the presence of classmates/TAs/instructors; Meet classmates to find groups for the final project; Group work time for the final project; Bring the class community together. Final project To satisfy the final project requirement for this course, students will have two options: (1) write a 1 page paper review (single-spaced) on a recent deep learning paper of your choice or (2) participate and present in the project proposal pitch competition. The 1 page paper review option is straightforward, we propose some papers within this document to help you get started, and you can satisfy a passing grade with this option -- you will not be eligible for the grand prizes. On the other hand, participation in the project proposal pitch competition will equivalently satisfy your course requirements but additionally make you eligible for the grand prizes. See the section below for more details and requirements for each of these options. Paper Review Students may satisfy the final project requirement by reading and reviewing a recent deep learning paper of their choosing. In the written review, students should provide both: 1) a description of the problem, technical approach, and results of the paper; 2) critical analysis and exposition of the limitations of the work and opportunities for future work. Reviews should be submitted on Canvas by Thursday Jan 28, 2021, 11:59:59pm Eastern Time (ET). Just a few paper options to consider... https://papers.nips.cc/paper/2017/file/3f5ee243547dee91fbd053c1c4a845aa-Paper.pdf https://papers.nips.cc/paper/2018/file/69386f6bb1dfed68692a24c8686939b9-Paper.pdf https://papers.nips.cc/paper/2020/file/1457c0d6bfcb4967418bfb8ac142f64a-Paper.pdf https://science.sciencemag.org/content/362/6419/1140 https://papers.nips.cc/paper/2018/file/0e64a7b00c83e3d22ce6b3acf2c582b6-Paper.pdf https://arxiv.org/pdf/1906.11829.pdf https://www.nature.com/articles/s42256-020-00237-3 https://pubmed.ncbi.nlm.nih.gov/32084340/ Project Proposal Presentation Keyword: proposal This is a 2 week course so we do not require results or working implementations! However, to win the top prizes, nice, clear results and implementations will demonstrate feasibility of your proposal which is something we look for! Logistics -- please read! You must sign up to present before 11:59:59pm Eastern Time (ET) on Wednesday Jan 27, 2021 Slides must be in a Google Slide before 11:59:59pm Eastern Time (ET) on Thursday Jan 28, 2021 Project groups can be between 1 and 5 people Listeners welcome To be eligible for a prize you must have at least 1 registered MIT student in your group Each participant will only be allowed to be in one group and present one project pitch Synchronous attendance on 1/29/21 is required to make the project pitch! 3 min presentation on your idea (we will be very strict with the time limits) Prizes! (see below) Sign up to Present here: by 11:59pm ET on Wednesday Jan 27 Once you sign up, make your slide in the following Google Slides; submit by midnight on Thursday Jan 28. Please specify the project group # on your slides!!! Things to Consider This doesn’t have to be a new deep learning method. It can just be an interesting application that you apply some existing deep learning method to. What problem are you solving? Are there use cases/applications? Why do you think deep learning methods might be suited to this task? How have people done it before? Is it a new task? If so, what are similar tasks that people have worked on? In what aspects have they succeeded or failed? What is your method of solving this problem? What type of model + architecture would you use? Why? What is the data for this task? Do you need to make a dataset or is there one publicly available? What are the characteristics of the data? Is it sparse, messy, imbalanced? How would you deal with that? Project Proposal Grading Rubric Project proposals will be evaluated by a panel of judges on the basis of the following three criteria: 1) novelty and impact; 2) technical soundness, feasibility, and organization, including quality of any presented results; 3) clarity and presentation. Each judge will award a score from 1 (lowest) to 5 (highest) for each of the criteria; the average score from each judge across these criteria will then be averaged with that of the other judges to provide the final score. The proposals with the highest final scores will be selected for prizes. Here are the guidelines for the criteria: Novelty and impact: encompasses the potential impact of the project idea, its novelty with respect to existing approaches. Why does the proposed work matter? What problem(s) does it solve? Why are these problems important? Technical soundness, feasibility, and organization: encompasses all technical aspects of the proposal. Do the proposed methodology and architecture make sense? Is the architecture the best suited for the proposed problem? Is deep learning the best approach for the problem? How realistic is it to implement the idea? Was there any implementation of the method? If results and data are presented, we will evaluate the strength of the results/data. Clarity and presentation: encompasses the delivery and quality of the presentation itself. Is the talk well organized? Are the slides aesthetically compelling? Is there a clear, well-delivered narrative? Are the problem and proposed method clearly presented? Past Project Proposal Ideas Recipe Generation with RNNs Can we compress videos with CNN + RNN? Music Generation with RNNs Style Transfer Applied to X GAN’s on a new modality Summarizing text/news articles Combining news articles about similar events Code or spec generation Multimodal speech → handwriting Generate handwriting based on keywords (i.e. cursive, slanted, neat) Predicting stock market trends Show language learners articles or videos at their level Transfer of writing style Chemical Synthesis with Recurrent Neural networks Transfer learning to learn something in a domain for which it’s hard or risky to gather data or do training RNNs to model some type of time series data Computer vision to coach sports players Computer vision system for safety brakes or warnings Use IBM Watson API to get the sentiment of your Facebook newsfeed Deep learning webcam to give wifi-access to friends or improve video chat in some way Domain-specific chatbot to help you perform a specific task Detect whether a signature is fraudulent Awards + Categories Final Project Awards: 1x NVIDIA RTX 3080 4x Google Home Max 3x Display Monitors Software Lab Awards: Bose headphones (Lab 1) Display monitor (Lab 2) Bebop drone (Lab 3) Important Links and Emails Course website: http://introtodeeplearning.com Course staff: introtodeeplearning-staff@mit.edu Piazza forum (MIT only): https://piazza.com/mit/spring2021/6s191 Canvas (MIT only): https://canvas.mit.edu/courses/8291 Software lab repository: https://github.com/aamini/introtodeeplearning Lab/office hour sessions (MIT only): https://gather.town/app/56toTnlBrsKCyFgj/MITDeepLearning

W3C Strategic Highlights September 2019 This report was prepared for the September 2019 W3C Advisory Committee Meeting (W3C Member link). See the accompanying W3C Fact Sheet — September 2019. For the previous edition, see the April 2019 W3C Strategic Highlights. For future editions of this report, please consult the latest version. A Chinese translation is available. ☰ Contents Introduction Future Web Standards Meeting Industry Needs Web Payments Digital Publishing Media and Entertainment Web & Telecommunications Real-Time Communications (WebRTC) Web & Networks Automotive Web of Things Strengthening the Core of the Web HTML CSS Fonts SVG Audio Performance Web Performance WebAssembly Testing Browser Testing and Tools WebPlatform Tests Web of Data Web for All Security, Privacy, Identity Internationalization (i18n) Web Accessibility Outreach to the world W3C Developer Relations W3C Training Translations W3C Liaisons Introduction This report highlights recent work of enhancement of the existing landscape of the Web platform and innovation for the growth and strength of the Web. 33 working groups and a dozen interest groups enable W3C to pursue its mission through the creation of Web standards, guidelines, and supporting materials. We track the tremendous work done across the Consortium through homogeneous work-spaces in Github which enables better monitoring and management. We are in the middle of a period where we are chartering numerous working groups which demonstrate the rapid degree of change for the Web platform: After 4 years, we are nearly ready to publish a Payment Request API Proposed Recommendation and we need to soon charter follow-on work. In the last year we chartered the Web Payment Security Interest Group. In the last year we chartered the Web Media Working Group with 7 specifications for next generation Media support on the Web. We have Accessibility Guidelines under W3C Member review which includes Silver, a new approach. We have just launched the Decentralized Identifier Working Group which has tremendous potential because Decentralized Identifier (DID) is an identifier that is globally unique, resolveable with high availability, and cryptographically verifiable. We have Privacy IG (PING) under W3C Member review which strengthens our focus on the tradeoff between privacy and function. We have a new CSS charter under W3C Member review which maps the group's work for the next three years. In this period, W3C and the WHATWG have succesfully completed the negotiation of a Memorandum of Understanding rooted in the mutual belief that that having two distinct specifications claiming to be normative is generally harmful for the Web community. The MOU, signed last May, describes how the two organizations are to collaborate on the development of a single authoritative version of the HTML and DOM specifications. W3C subsequently rechartered the HTML Working Group to assist the W3C community in raising issues and proposing solutions for the HTML and DOM specifications, and for the production of W3C Recommendations from WHATWG Review Drafts. As the Web evolves continuously, some groups are looking for ways for specifications to do so as well. So-called "evergreen recommendations" or "living standards" aim to track continuous development (and maintenance) of features, on a feature-by-feature basis, while getting review and patent commitments. We see the maturation and further development of an incredible number of new technologies coming to the Web. Continued progress in many areas demonstrates the vitality of the W3C and the Web community, as the rest of the report illustrates. Future Web Standards W3C has a variety of mechanisms for listening to what the community thinks could become good future Web standards. These include discussions with the Membership, discussions with other standards bodies, the activities of thousands of participants in over 300 community groups, and W3C Workshops. There are lots of good ideas. The W3C strategy team has been identifying promising topics and invites public participation. Future, recent and under consideration Workshops include: Inclusive XR (5-6 November 2019, Seattle, WA, USA) to explore existing and future approaches on making Virtual and Augmented Reality experiences more inclusive, including to people with disabilities; W3C Workshop on Data Models for Transportation (12-13 September 2019, Palo Alto, CA, USA) W3C Workshop on Web Games (27-28 June 2019, Redmond, WA, USA), view report Second W3C Workshop on the Web of Things (3-5 June 2019, Munich, Germany) W3C Workshop on Web Standardization for Graph Data; Creating Bridges: RDF, Property Graph and SQL (4-6 March 2019, Berlin, Germany), view report Web & Machine Learning. The Strategy Funnel documents the staff's exploration of potential new work at various phases: Exploration and Investigation, Incubation and Evaluation, and eventually to the chartering of a new standards group. The Funnel view is a GitHub Project where new area are issues represented by “cards” which move through the columns, usually from left to right. Most cards start in Exploration and move towards Chartering, or move out of the funnel. Public input is welcome at any stage but particularly once Incubation has begun. This helps W3C identify work that is sufficiently incubated to warrant standardization, to review the ecosystem around the work and indicate interest in participating in its standardization, and then to draft a charter that reflects an appropriate scope. Ongoing feedback can speed up the overall standardization process. Since the previous highlights document, W3C has chartered a number of groups, and started discussion on many more: Newly Chartered or Rechartered Web Application Security WG (03-Apr) Web Payment Security IG (17-Apr) Patent and Standards IG (24-Apr) Web Applications WG (14-May) Web & Networks IG (16-May) Media WG (23-May) Media and Entertainment IG (06-Jun) HTML WG (06-Jun) Decentralized Identifier WG (05-Sep) Extended Privacy IG (PING) (30-Sep) Verifiable Claims WG (30-Sep) Service Workers WG (31-Dec) Dataset Exchange WG (31-Dec) Web of Things Working Group (31-Dec) Web Audio Working Group (31-Dec) Proposed charters / Advance Notice Accessibility Guidelines WG Privacy IG (PING) RDF Literal Direction WG Timed Text WG CSS WG Web Authentication WG Closed Internationalization Tag Set IG Meeting Industry Needs Web Payments All Web Payments specifications W3C's payments standards enable a streamlined checkout experience, enabling a consistent user experience across the Web with lower front end development costs for merchants. Users can store and reuse information and more quickly and accurately complete online transactions. The Web Payments Working Group has republished Payment Request API as a Candidate Recommendation, aiming to publish a Proposed Recommendation in the Fall 2019, and is discussing use cases and features for Payment Request after publication of the 1.0 Recommendation. Browser vendors have been finalizing implementation of features added in the past year (view the implementation report). As work continues on the Payment Handler API and its implementation (currently in Chrome and Edge Canary), one focus in 2019 is to increase adoption in other browsers. Recently, Mastercard demonstrated the use of Payment Request API to carry out EMVCo's Secure Remote Commerce (SRC) protocol whose payment method definition is being developed with active participation by Visa, Mastercard, American Express, and Discover. Payment method availability is a key factor in merchant considerations about adopting Payment Request API. The ability to get uniform adoption of a new payment method such as Secure Remote Commerce (SRC) also depends on the availability of the Payment Handler API in browsers, or of proprietary alternatives. Web Monetization, which the Web Payments Working Group will discuss again at its face-to-face meeting in September, can be used to enable micropayments as an alternative revenue stream to advertising. Since the beginning of 2019, Amazon, Brave Software, JCB, Certus Cybersecurity Solutions and Netflix have joined the Web Payments Working Group. In April, W3C launched the Web Payment Security Group to enable W3C, EMVCo, and the FIDO Alliance to collaborate on a vision for Web payment security and interoperability. Participants will define areas of collaboration and identify gaps between existing technical specifications in order to increase compatibility among different technologies, such as: How do SRC, FIDO, and Payment Request relate? The Payment Services Directive 2 (PSD2) regulations in Europe are scheduled to take effect in September 2019. What is the role of EMVCo, W3C, and FIDO technologies, and what is the current state of readiness for the deadline? How can we improve privacy on the Web at the same time as we meet industry requirements regarding user identity? Digital Publishing All Digital Publishing specifications, Publication milestones The Web is the universal publishing platform. Publishing is increasingly impacted by the Web, and the Web increasingly impacts Publishing. Topic of particular interest to Publishing@W3C include typography and layout, accessibility, usability, portability, distribution, archiving, offline access, print on demand, and reliable cross referencing. And the diverse publishing community represented in the groups consist of the traditional "trade" publishers, ebook reading system manufacturers, but also publishers of audio book, scholarly journals or educational materials, library scientists or browser developers. The Publishing Working Group currently concentrates on Audiobooks which lack a comprehensive standard, thus incurring extra costs and time to publish in this booming market. Active development is ongoing on the future standard: Publication Manifest Audiobook profile for Web Publications Lightweight Packaging Format The BD Comics Manga Community Group, the Synchronized Multimedia for Publications Community Group, the Publishing Community Group and a future group on archival, are companions to the working group where specific work is developed and incubated. The Publishing Community Group is a recently launched incubation channel for Publishing@W3C. The goal of the group is to propose, document, and prototype features broadly related to: publications on the Web reading modes and systems and the user experience of publications The EPUB 3 Community Group has successfully completed the revision of EPUB 3.2. The Publishing Business Group fosters ongoing participation by members of the publishing industry and the overall ecosystem in the development of Web infrastructure to better support the needs of the industry. The Business Group serves as an additional conduit to the Publishing Working Group and several Community Groups for feedback between the publishing ecosystem and W3C. The Publishing BG has played a vital role in fostering and advancing the adoption and continued development of EPUB 3. In particular the BG provided critical support to the update of EPUBCheck to validate EPUB content to the new EPUB 3.2 specification. This resulted in the development, in conjunction with the EPUB3 Community Group, of a new generation of EPUBCheck, i.e., EPUBCheck 4.2 production-ready release. Media and Entertainment All Media specifications The Media and Entertainment vertical tracks media-related topics and features that create immersive experiences for end users. HTML5 brought standard audio and video elements to the Web. Standardization activities since then have aimed at turning the Web into a professional platform fully suitable for the delivery of media content and associated materials, enabling missing features to stream video content on the Web such as adaptive streaming and content protection. Together with Microsoft, Comcast, Netflix and Google, W3C received an Technology & Engineering Emmy Award in April 2019 for standardization of a full TV experience on the Web. Current goals are to: Reinforce core media technologies: Creation of the Media Working Group, to develop media-related specifications incubated in the WICG (e.g. Media Capabilities, Picture-in-picture, Media Session) and maintain maintain/evolve Media Source Extensions (MSE) and Encrypted Media Extensions (EME). Improve support for Media Timed Events: data cues incubation. Enhance color support (HDR, wide gamut), in scope of the CSS WG and in the Color on the Web CG. Reduce fragmentation: Continue annual releases of a common and testable baseline media devices, in scope of the Web Media APIs CG and in collaboration with the CTA WAVE Project. Maintain the Road-map of Media Technologies for the Web which highlights Web technologies that can be used to build media applications and services, as well as known gaps to enable additional use cases. Create the future: Discuss perspectives for Media and Entertainment for the Web. Bring the power of GPUs to the Web (graphics, machine learning, heavy processing), under incubation in the GPU for the Web CG. Transition to a Working Group is under discussion. Determine next steps after the successful W3C Workshop on Web Games of June 2019. View the report. Timed Text The Timed Text Working Group develops and maintains formats used for the representation of text synchronized with other timed media, like audio and video, and notably works on TTML, profiles of TTML, and WebVTT. Recent progress includes: A robust WebVTT implementation report poises the specification for publication as a proposed recommendation. Discussions around re-chartering, notably to add a TTML Profile for Audio Description deliverable to the scope of the group, and clarify that rendering of captions within XR content is also in scope. Immersive Web Hardware that enables Virtual Reality (VR) and Augmented Reality (AR) applications are now broadly available to consumers, offering an immersive computing platform with both new opportunities and challenges. The ability to interact directly with immersive hardware is critical to ensuring that the web is well equipped to operate as a first-class citizen in this environment. The Immersive Web Working Group has been stabilizing the WebXR Device API while the companion Immersive Web Community Group incubates the next series of features identified as key for the future of the Immersive Web. W3C plans a workshop focused on the needs and benefits at the intersection of VR & Accessibility (Inclusive XR), on 5-6 November 2019 in Seattle, WA, USA, to explore existing and future approaches on making Virtual and Augmented Reality experiences more inclusive. Web & Telecommunications The Web is the Open Platform for Mobile. Telecommunication service providers and network equipment providers have long been critical actors in the deployment of Web technologies. As the Web platform matures, it brings richer and richer capabilities to extend existing services to new users and devices, and propose new and innovative services. Real-Time Communications (WebRTC) All Real-Time Communications specifications WebRTC has reshaped the whole communication landscape by making any connected device a potential communication end-point, bringing audio and video communications anywhere, on any network, vastly expanding the ability of operators to reach their customers. WebRTC serves as the corner-stone of many online communication and collaboration services. The WebRTC Working Group aims to bringing WebRTC 1.0 (and companion specification Media Capture and Streams) to Recommendation by the end of 2019. Intense efforts are focused on testing (supported by a dedicated hackathon at IETF 104) and interoperability. The group is considering pushing features that have not gotten enough traction to separate modules or to a later minor revision of the spec. Beyond WebRTC 1.0, the WebRTC Working Group will focus its efforts on WebRTC NV which the group has started documenting by identifying use cases. Web & Networks Recently launched, in the wake of the May 2018 Web5G workshop, the Web & Networks Interest Group is chaired by representatives from AT&T, China Mobile and Intel, with a goal to explore solutions for web applications to achieve better performance and resource allocation, both on the device and network. The group's first efforts are around use cases, privacy & security requirements and liaisons. Automotive All Automotive specifications To create a rich application ecosystem for vehicles and other devices allowed to connect to the vehicle, the W3C Automotive Working Group is delivering a service specification to expose all common vehicle signals (engine temperature, fuel/charge level, range, tire pressure, speed, etc.) The Vehicle Information Service Specification (VISS), which is a Candidate Recommendation, is seeing more implementations across the industry. It provides the access method to a common data model for all the vehicle signals –presently encapsulating a thousand or so different data elements– and will be growing to accommodate the advances in automotive such as autonomous and driver assist technologies and electrification. The group is already working on a successor to VISS, leveraging the underlying data model and the VIWI submission from Volkswagen, for a more robust means of accessing vehicle signals information and the same paradigm for other automotive needs including location-based services, media, notifications and caching content. The Automotive and Web Platform Business Group acts as an incubator for prospective standards work. One of its task forces is using W3C VISS in performing data sampling and off-boarding the information to the cloud. Access to the wealth of information that W3C's auto signals standard exposes is of interest to regulators, urban planners, insurance companies, auto manufacturers, fleet managers and owners, service providers and others. In addition to components needed for data sampling and edge computing, capturing user and owner consent, information collection methods and handling of data are in scope. The upcoming W3C Workshop on Data Models for Transportation (September 2019) is expected to focus on the need of additional ontologies around transportation space. Web of Things All Web of Things specifications W3C's Web of Things work is designed to bridge disparate technology stacks to allow devices to work together and achieve scale, thus enabling the potential of the Internet of Things by eliminating fragmentation and fostering interoperability. Thing descriptions expressed in JSON-LD cover the behavior, interaction affordances, data schema, security configuration, and protocol bindings. The Web of Things complements existing IoT ecosystems to reduce the cost and risk for suppliers and consumers of applications that create value by combining multiple devices and information services. There are many sectors that will benefit, e.g. smart homes, smart cities, smart industry, smart agriculture, smart healthcare and many more. The Web of Things Working Group is finishing the initial Web of Things standards, with support from the Web of Things Interest Group: Web of Things Architecture Thing Descriptions Strengthening the Core of the Web HTML The HTML Working Group was chartered early June to assist the W3C community in raising issues and proposing solutions for the HTML and DOM specifications, and to produce W3C Recommendations from WHATWG Review Drafts. A few days before, W3C and the WHATWG signed a Memorandum of Understanding outlining the agreement to collaborate on the development of a single version of the HTML and DOM specifications. Issues and proposed solutions for HTML and DOM done via the newly rechartered HTML Working Group in the WHATWG repositories The HTML Working Group is targetting November 2019 to bring HTML and DOM to Candidate Recommendations. CSS All CSS specifications CSS is a critical part of the Open Web Platform. The CSS Working Group gathers requirements from two large groups of CSS users: the publishing industry and application developers. Within W3C, those groups are exemplified by the Publishing groups and the Web Platform Working Group. The former requires things like better pagination support and advanced font handling, the latter needs intelligent (and fast!) scrolling and animations. What we know as CSS is actually a collection of almost a hundred specifications, referred to as ‘modules’. The current state of CSS is defined by a snapshot, updated once a year. The group also publishes an index defining every term defined by CSS specifications. Fonts All Fonts specifications The Web Fonts Working Group develops specifications that allow the interoperable deployment of downloadable fonts on the Web, with a focus on Progressive Font Enrichment as well as maintenance of WOFF Recommendations. Recent and ongoing work includes: Early API experiments by Adobe and Monotype have demonstrated the feasibility of a font enrichment API, where a server delivers a font with minimal glyph repertoire and the client can query the full repertoire and request additional subsets on-the-fly. In other experiments, the Brotli compression used in WOFF 2 was extended to support shared dictionaries and patch update. Metrics to quantify improvement are a current hot discussion topic. The group will meet at ATypi 2019 in Japan, to gather requirements from the international typography community. The group will first produce a report summarizing the strengths and weaknesses of each prototype solution by Q2 2020. SVG All SVG specifications SVG is an important and widely-used part of the Open Web Platform. The SVG Working Group focuses on aligning the SVG 2.0 specification with browser implementations, having split the specification into a currently-implemented 2.0 and a forward-looking 2.1. Current activity is on stabilization, increased integration with the Open Web Platform, and test coverage analysis. The Working Group was rechartered in March 2019. A new work item concerns native (non-Web-browser) uses of SVG as a non-interactive, vector graphics format. Audio The Web Audio Working Group was extended to finish its work on the Web Audio API, expecting to publish it as a Recommendation by year end. The specification enables synthesizing audio in the browser. Audio operations are performed with audio nodes, which are linked together to form a modular audio routing graph. Multiple sources — with different types of channel layout — are supported. This modular design provides the flexibility to create complex audio functions with dynamic effects. The first version of Web Audio API is now feature complete and is implemented in all modern browsers. Work has started on the next version, and new features are being incubated in the Audio Community Group. Performance Web Performance All Web Performance specifications There are currently 18 specifications in development in the Web Performance Working Group aiming to provide methods to observe and improve aspects of application performance of user agent features and APIs. The W3C team is looking at related work incubated in the W3C GPU for the Web (WebGPU) Community Group which is poised to transition to a W3C Working Group. A preliminary draft charter is available. WebAssembly All WebAssembly specifications WebAssembly improves Web performance and power by being a virtual machine and execution environment enabling loaded pages to run native (compiled) code. It is deployed in Firefox, Edge, Safari and Chrome. The specification will soon reach Candidate Recommendation. WebAssembly enables near-native performance, optimized load time, and perhaps most importantly, a compilation target for existing code bases. While it has a small number of native types, much of the performance increase relative to Javascript derives from its use of consistent typing. WebAssembly leverages decades of optimization for compiled languages and the byte code is optimized for compactness and streaming (the web page starts executing while the rest of the code downloads). Network and API access all occurs through accompanying Javascript libraries -- the security model is identical to that of Javascript. Requirements gathering and language development occur in the Community Group while the Working Group manages test development, community review and progression of specifications on the Recommendation Track. Testing Browser testing plays a critical role in the growth of the Web by: Improving the reliability of Web technology definitions; Improving the quality of implementations of these technologies by helping vendors to detect bugs in their products; Improving the data available to Web developers on known bugs and deficiencies of Web technologies by publishing results of these tests. Browser Testing and Tools The Browser Testing and Tools Working Group is developing WebDriver version 2, having published last year the W3C Recommendation of WebDriver. WebDriver acts as a remote control interface that enables introspection and control of user agents, provides a platform- and language-neutral wire protocol as a way for out-of-process programs to remotely instruct the behavior of Web, and emulates the actions of a real person using the browser. WebPlatform Tests The WebPlatform Tests project now provides a mechanism which allows to fully automate tests that previously needed to be run manually: TestDriver. TestDriver enables sending trusted key and mouse events, sending complex series of trusted pointer and key interactions for things like in-content drag-and-drop or pinch zoom, and even file upload. Since 2014 W3C began work on this coordinated open-source effort to build a cross-browser test suite for the Web Platform, which WHATWG, and all major browsers adopted. Web of Data All Data specifications There have been several great success stories around the standardization of data on the web over the past year. Verifiable Claims seems to have significant uptake. It is also significant that the Distributed Identifier WG charter has received numerous favorable reviews, and was just recently launched. JSON-LD has been a major success with the large deployment on Web sites via schema.org. JSON-LD 1.1 completed technical work, about to transition to CR More than 25% of websites today include schema.org data in JSON-LD The Web of Things description is in CR since May, making use of JSON-LD Verifiable Credentials data model is in CR since July, also making use of JSON-LD Continued strong interest in decentralized identifiers Engagement from the TAG with reframing core documents, such as Ethical Web Principles, to include data on the web within their scope Data is increasingly important for all organizations, especially with the rise of IoT and Big Data. W3C has a mature and extensive suite of standards relating to data that were developed over two decades of experience, with plans for further work on making it easier for developers to work with graph data and knowledge graphs. Linked Data is about the use of URIs as names for things, the ability to dereference these URIs to get further information and to include links to other data. There are ever-increasing sources of open Linked Data on the Web, as well as data services that are restricted to the suppliers and consumers of those services. The digital transformation of industry is seeking to exploit advanced digital technologies. This will facilitate businesses to integrate horizontally along the supply and value chains, and vertically from the factory floor to the office floor. W3C is seeking to make it easier to support enterprise-wide data management and governance, reflecting the strategic importance of data to modern businesses. Traditional approaches to data have focused on tabular databases (SQL/RDBMS), Comma Separated Value (CSV) files, and data embedded in PDF documents and spreadsheets. We're now in midst of a major shift to graph data with nodes and labeled directed links between them. Graph data is: Faster than using SQL and associated JOIN operations More favorable to integrating data from heterogeneous sources Better suited to situations where the data model is evolving In the wake of the recent W3C Workshop on Graph Data we are in the process of launching a Graph Standardization Business Group to provide a business perspective with use cases and requirements, to coordinate technical standards work and liaisons with external organizations. Web for All Security, Privacy, Identity All Security specifications, all Privacy specifications Authentication on the Web As the WebAuthn Level 1 W3C Recommendation published last March is seeing wide implementation and adoption of strong cryptographic authentication, work is proceeding on Level 2. The open standard Web API gives native authentication technology built into native platforms, browsers, operating systems (including mobile) and hardware, offering protection against hacking, credential theft, phishing attacks, thus aiming to end the era of passwords as a security construct. You may read more in our March press release. Privacy An increasing number of W3C specifications are benefitting from Privacy and Security review; there are security and privacy aspects to every specification. Early review is essential. Working with the TAG, the Privacy Interest Group has updated the Self-Review Questionnaire: Security and Privacy. Other recent work of the group includes public blogging further to the exploration of anti-patterns in standards and permission prompts. Security The Web Application Security Working Group adopted Feature Policy, aiming to allow developers to selectively enable, disable, or modify the behavior of some of these browser features and APIs within their application; and Fetch Metadata, aiming to provide servers with enough information to make a priori decisions about whether or not to service a request based on the way it was made, and the context in which it will be used. The Web Payment Security Interest Group, launched last April, convenes members from W3C, EMVCo, and the FIDO Alliance to discuss cooperative work to enhance the security and interoperability of Web payments (read more about payments). Internationalization (i18n) All Internationalization specifications, educational articles related to Internationalization, spec developers checklist Only a quarter or so current Web users use English online and that proportion will continue to decrease as the Web reaches more and more communities of limited English proficiency. If the Web is to live up to the "World Wide" portion of its name, and for the Web to truly work for stakeholders all around the world engaging with content in various languages, it must support the needs of worldwide users as they engage with content in the various languages. The growth of epublishing also brings requirements for new features and improved typography on the Web. It is important to ensure the needs of local communities are captured. The W3C Internationalization Initiative was set up to increase in-house resources dedicated to accelerating progress in making the World Wide Web "worldwide" by gathering user requirements, supporting developers, and education & outreach. For an overview of current projects see the i18n radar. W3C's Internationalization efforts progressed on a number of fronts recently: Requirements: New African and European language groups will work on the gap analysis, errata and layout requirements. Gap analysis: Japanese, Devanagari, Bengali, Tamil, Lao, Khmer, Javanese, and Ethiopic updated in the gap-analysis documents. Layout requirements document: notable progress tracked in the Southeast Asian Task Force while work continues on Chinese layout requirements. Developer support: Spec reviews: the i18n WG continues active review of specifications of the WHATWG and other W3C Working Groups. Short review checklist: easy way to begin a self-review to help spec developers understand what aspects of their spec are likely to need attention for internationalization, and points them to more detailed checklists for the relevant topics. It also helps those reviewing specs for i18n issues. Strings on the Web: Language and Direction Metadata lays out issues and discusses potential solutions for passing information about language and direction with strings in JSON or other data formats. The document was rewritten for clarity, and expanded. The group is collaborating with the JSON-LD and Web Publishing groups to develop a plan for updating RDF, JSON-LD and related specifications to handle metadata for base direction of text (bidi). User-friendly test format: a new format was developed for Internationalization Test Suite tests, which displays helpful information about how the test works. This particularly useful because those tests are pointed to by educational materials and gap-analysis documents. Web Platform Tests: a large number of tests in the i18n test suite have been ported to the WPT repository, including: css-counter-styles, css-ruby, css-syntax, css-test, css-text-decor, css-writing-modes, and css-pseudo. Education & outreach: (for all educational materials, see the HTML & CSS Authoring Techniques) Web Accessibility All Accessibility specifications, WAI resources The Web Accessibility Initiative supports W3C's Web for All mission. Recent achievements include: Education and training: Inaccessibility of CAPTCHA updated to bring our analysis and recommendations up to date with CAPTCHA practice today, concluding two years of extensive work and invaluable input from the public (read more on the W3C Blog Learn why your web content and applications should be accessible. The Education and Outreach Working Group has completed revision and updating of the Business Case for Digital Accessibility. Accessibility guidelines: The Accessibility Guidelines Working Group has continued to update WCAG Techniques and Understanding WCAG 2.1; and published a Candidate Recommendation of Accessibility Conformance Testing Rules Format 1.0 to improve inter-rater reliability when evaluating conformance of web content to WCAG An updated charter is being developed to host work on "Silver", the next generation accessibility guidelines (WCAG 2.2) There are accessibility aspects to most specifications. Check your work with the FAST checklist. Outreach to the world W3C Developer Relations To foster the excellent feedback loop between Web Standards development and Web developers, and to grow participation from that diverse community, recent W3C Developer Relations activities include: @w3cdevs tracks the enormous amount of work happening across W3C W3C Track during the Web Conference 2019 in San Francisco Tech videos: W3C published the 2019 Web Games Workshop videos The 16 September 2019 Developer Meetup in Fukuoka, Japan, is open to all and will combine a set of technical demos prepared by W3C groups, and a series of talks on a selected set of W3C technologies and projects W3C is involved with Mozilla, Google, Samsung, Microsoft and Bocoup in the organization of ViewSource 2019 in Amsterdam (read more on the W3C Blog) W3C Training In partnership with EdX, W3C's MOOC training program, W3Cx offers a complete "Front-End Web Developer" (FEWD) professional certificate program that consists of a suite of five courses on the foundational languages that power the Web: HTML5, CSS and JavaScript. We count nearly 900K students from all over the world. Translations Many Web users rely on translations of documents developed at W3C whose official language is English. W3C is extremely grateful to the continuous efforts of its community in ensuring our various deliverables in general, and in our specifications in particular, are made available in other languages, for free, ensuring their exposure to a much more diverse set of readers. Last Spring we developed a more robust system, a new listing of translations of W3C specifications and updated the instructions on how to contribute to our translation efforts. W3C Liaisons Liaisons and coordination with numerous organizations and Standards Development Organizations (SDOs) is crucial for W3C to: make sure standards are interoperable coordinate our respective agenda in Internet governance: W3C participates in ICANN, GIPO, IGF, the I* organizations (ICANN, IETF, ISOC, IAB). ensure at the government liaison level that our standards work is officially recognized when important to our membership so that products based on them (often done by our members) are part of procurement orders. W3C has ARO/PAS status with ISO. W3C participates in the EU MSP and Rolling Plan on Standardization ensure the global set of Web and Internet standards form a compatible stack of technologies, at the technical and policy level (patent regime, fragmentation, use in policy making) promote Standards adoption equally by the industry, the public sector, and the public at large Coralie Mercier, Editor, W3C Marketing & Communications $Id: Overview.html,v 1.60 2019/10/15 12:05:52 coralie Exp $ Copyright © 2019 W3C ® (MIT, ERCIM, Keio, Beihang) Usage policies apply.

LLM prompts for structured software development because quality takes more than just "good vibes".

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aiptag.cmd.display = aiptag.cmd.display || []; </script> <!-- Fonts --> <link href="/~/https://fonts.googleapis.com/css?family=Roboto+Condensed:400,700" rel="stylesheet"> <link href="css/app.dacc77a5.css" rel="stylesheet"><meta name="ROBOTS" content="NOINDEX, NOFOLLOW"/> </head> <body> <div id='preroll-wrapper'> <div id="preroll"></div> </div> <div id="fb-root"></div> <canvas tabindex='1' id='cvs'></canvas> <div id='game-area-wrapper' style='display: none' oncontextmenu='return false;'> <div id='game-touch-area'></div> <!-- Class Select --> <div id='ui-role-menu-wrapper'> <div id='ui-role-menu'> <div id='ui-role-header'></div> <div id='ui-role-body'></div> <div id='ui-role-footer'> <div id='ui-role-footer-desc' data-l10n='game-select-class'>SELECT A CLASS</div> <div id='ui-role-footer-enter'>ENTER GAME (20)</div> </div> </div> </div> <div id='ui-game' class='click-through'> <div id='tablet-console'></div> <div id='ui-center'> <div id='ui-game-menu'> <div id='btn-game-tabs' class='btns-game-double-row'> <div class='btn-game-container'> <a id='btn-game-settings' class='btn-game-tab-select btn-game-menu btn-game-menu-selected btn-darken' data-tab='settings'></a> <div class='btn-double-row game-menu-icon-static settings-icon'></div> </div> <div class='btn-game-container'> <a id='btn-game-keybinds' class='btn-game-tab-select btn-game-menu btn-darken' data-tab='keybinds'></a> <div class='btn-double-row game-menu-icon-static keybind-icon'></div> </div> </div> <div id='ui-game-tab-settings' class='ui-game-tab'> <a id='btn-game-fullscreen' class='btn-fullscreen-toggle btn-game-menu btn-darken' data-l10n='game-full-screen'>Full Screen</a> <div id='btn-touch-styles' class='btns-game-double-row'> <div class='btn-game-container'> <a id='btn-game-move-style' class='btn-double-row btn-game-touch-style btn-darken'></a> <div class='btn-double-row game-menu-icon-toggle movement-icon'></div> </div> <div class='btn-game-container'> <a id='btn-game-aim-style' class='btn-double-row btn-game-touch-style btn-darken'></a> <div class='btn-double-row game-menu-icon-toggle target-icon'></div> </div> </div> <a id='btn-game-aim-line' class='btn-game-menu btn-darken locked-on-icon' data-l10n='game-aim-line'>Aim Line</a> <a id='btn-game-sound' class='btn-sound-toggle btn-game-menu btn-darken audio-on-icon' data-l10n='game-sound'>Sound</a> <div class="slider-container ui-slider-container"> <p class='slider-text' data-l10n='index-master-volume'>Master Volume</p> <input type="range" min="0" max="100" value="100" class="slider sl-master-volume"> </div> <div class="slider-container ui-slider-container"> <p class='slider-text' data-l10n='index-sfx-volume'>SFX Volume</p> <input type="range" min="0" max="100" value="100" class="slider sl-sound-volume"> </div> <div class="slider-container ui-slider-container"> <p class='slider-text' data-l10n='index-music-volume'>Music Volume</p> <input type="range" min="0" max="100" value="100" class="slider sl-music-volume"> </div> <a id='btn-game-quit' class='btn-quit btn-game-menu btn-darken' data-l10n='game-quit-game'>Quit Game</a> </div> <div id='ui-game-tab-keybinds' class='ui-game-tab'> <div id='ui-keybind-list' class='js-keybind-list'></div> <a class='js-btn-keybind-restore btn-keybind-restore btn-game-menu btn-darken' data-l10n='game-restore-defaults'>Restore Defaults</a> </div> <a id='btn-game-resume' class='btn-game-menu btn-darken' data-l10n='game-return-to-game'>Return to Game</a> </div> </div> <div id='big-map' class='js-ui-map-show'> <div id='big-map-collision'></div> <div id='big-map-close'></div> </div> <div id='ui-emotes' class='ui-emote-wheel'> <div id='ui-emote-middle' class='ui-emote-middle ui-emote-circle ui-emote-parent' data-key='middle' data-id='0'> <div class='ui-emote ui-emote-bg-circle'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-emote-top' class='ui-emote-top ui-emote-quarter ui-emote-parent' data-key='top' data-id='1'> <div class='ui-emote ui-emote-bg-quarter'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-emote-right' class='ui-emote-right ui-emote-quarter ui-emote-parent' data-key='right' data-id='2'> <div class='ui-emote ui-emote-bg-quarter'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-emote-bottom' class='ui-emote-bottom ui-emote-quarter ui-emote-parent' data-key='bottom' data-id='3'> <div class='ui-emote ui-emote-bg-quarter'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-emote-left' class='ui-emote-left ui-emote-quarter ui-emote-parent' data-key='left' data-id='4'> <div class='ui-emote ui-emote-bg-quarter'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> </div> <div id='ui-team-pings' class='ui-emote-wheel'> <div id='ui-team-ping-middle' class='ui-emote-middle ui-emote-circle ui-emote-parent' data-id='0'> <div class='ui-emote ui-emote-bg-circle'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-team-ping-top' class='ui-emote-top ui-emote-quarter ui-emote-parent' data-id='1'> <div class='ui-emote ui-emote-bg-quarter'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-team-ping-right' class='ui-emote-right ui-emote-quarter ui-emote-parent' data-id='2'> <div class='ui-emote ui-emote-bg-quarter'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-team-ping-bottom' class='ui-emote-bottom ui-emote-quarter ui-emote-parent' data-id='3'> <div class='ui-emote ui-emote-bg-quarter'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-large'></div> </div> <div id='ui-team-ping-bottom-left' class='ui-emote-bottom-left ui-emote-eighth ui-emote-parent' data-id='4'> <div class='ui-emote ui-emote-bg-eighth'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-small'></div> </div> <div id='ui-team-ping-top-left' class='ui-emote-top-left ui-emote-eighth ui-emote-parent' data-id='5'> <div class='ui-emote ui-emote-bg-eighth'></div> <div class='ui-emote ui-emote-hl'></div> <div class='ui-emote-image ui-emote-image-small'></div> </div> </div> <div id='ui-team-indicators' class='js-ui-map-hidden js-desktop-ui-hud-show'> <div class='ui-team-indicator ui-indicator-main' data-id='0'> <div class='ui-team-indicator-pos ui-background-yellow'></div> </div> <div class='ui-team-indicator ui-indicator-main' data-id='1'> <div class='ui-team-indicator-pos ui-background-purple'></div> </div> <div class='ui-team-indicator ui-indicator-main' data-id='2'> <div class='ui-team-indicator-pos ui-background-cyan'></div> </div> <div class='ui-team-indicator ui-indicator-main' data-id='3'> <div class='ui-team-indicator-pos ui-background-orange'></div> </div> <div class='ui-team-indicator ui-indicator-main' data-id='4'> <div class='ui-team-indicator-pos ui-background-yellow'></div> </div> <div class='ui-team-indicator ui-indicator-ping' data-id='0'> <div class='ui-team-indicator-pos ui-team-indicator-image'></div> </div> <div class='ui-indicator-ping-border' data-id='0'></div> <div class='ui-team-indicator ui-indicator-ping' data-id='1'> <div class='ui-team-indicator-pos ui-team-indicator-image'></div> </div> <div class='ui-indicator-ping-border' data-id='1'></div> <div class='ui-team-indicator ui-indicator-ping' data-id='2'> <div class='ui-team-indicator-pos ui-team-indicator-image'></div> </div> <div class='ui-indicator-ping-border' data-id='2'></div> <div class='ui-team-indicator ui-indicator-ping' data-id='3'> <div class='ui-team-indicator-pos ui-team-indicator-image'></div> </div> <div class='ui-indicator-ping-border' data-id='3'></div> <div class='ui-team-indicator ui-indicator-ping' data-id='4'> <div class='ui-team-indicator-pos ui-team-indicator-image'></div> </div> <div class='ui-indicator-ping-border' data-id='4'></div> </div> <div id='ui-right-center' class='ui-right-center-desktop js-ui-map-hidden'> <div id='ui-medical-interactive'> <div id='ui-loot-bandage' class='ui-loot ui-outline-hover ui-scale-hover ui-medical tooltip'> <div class='tooltip-text'> <div class='tooltip-title' data-l10n='game-bandage'>Bandage</div> <div class='tooltip-description'><span data-l10n='game-bandage-tooltip'>Left-click to restore 15 health.</span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> </div> <div id='ui-loot-healthkit' class='ui-loot ui-outline-hover ui-scale-hover ui-medical tooltip'> <div class='tooltip-text'> <div class='tooltip-title' data-l10n='game-healthkit'>Med Kit</div> <div class='tooltip-description'><span data-l10n='game-healthkit-tooltip'>Left-click to restore 100 health.</div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> </div> <div id='ui-loot-soda' class='ui-loot ui-outline-hover ui-scale-hover ui-medical tooltip'> <div class='tooltip-text'> <div class='tooltip-title' data-l10n='game-soda'>Soda</div> <div class='tooltip-description'><span data-l10n='game-soda-tooltip'>Left-click to boost adrenaline by 25.</span><br><span data-l10n='game-adrenaline-tooltip'>Adrenaline restores health over time.</span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> </div> <div id='ui-loot-chocolateBox' class='ui-loot ui-outline-hover ui-scale-hover ui-medical tooltip'> <div class='tooltip-text'> <div class='tooltip-title' data-l10n='game-chocolateBox'>ChocolateBox</div> <div class='tooltip-description'><span data-l10n='game-soda-tooltip'>Left-click to boost adrenaline by 25.</span><br><span data-l10n='game-adrenaline-tooltip'>Adrenaline restores health over time.</span><br><span data-l10n='game-chocolateBox-tooltip'>Inmune to frenemy effect for 20s.</span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> </div> <div id='ui-loot-painkiller' class='ui-loot ui-outline-hover ui-scale-hover ui-medical tooltip'> <div class='tooltip-text'> <div class='tooltip-title' data-l10n='game-painkiller'>Pills</div> <div class='tooltip-description'><span data-l10n='game-painkiller-tooltip'>Left-click to boost adrenaline by 50.</div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> </div> <div id='ui-loot-flask' class='ui-loot ui-outline-hover ui-scale-hover ui-medical tooltip'> <div class='tooltip-text'> <div class='tooltip-title' data-l10n='game-flask'>Flask</div> <div class='tooltip-description'><span data-l10n='game-flask-tooltip'>Left-click for freeze damage immunity for 20 seconds.</span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> </div> </div> <div id='ui-ammo-interactive'> <div id='ui-loot-50AE' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-50AE'></div> <div class='tooltip-description'><span data-l10n='game-50AE-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(30,30,30,0.75)'></div> </div> <div id='ui-loot-9mm' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-9mm'></div> <div class='tooltip-description'><span data-l10n='game-9mm-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(255,153,0,0.75)'></div> </div> <div id='ui-loot-308sub' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-308sub'></div> <div class='tooltip-description'><span data-l10n='game-308sub-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(49,56,0,0.75)'></div> </div> <div id='ui-loot-12gauge' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-12gauge'></div> <div class='tooltip-description'><span data-l10n='game-12gauge-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(255,0,0,0.75)'></div> </div> <div id='ui-loot-flare' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-flare'></div> <div class='tooltip-description'><span data-l10n='game-flare-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(255,85,0,0.75)'></div> </div> <div id='ui-loot-762mm' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-762mm'></div> <div class='tooltip-description'><span data-l10n='game-762mm-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(0,102,255,0.75)'></div> </div> <div id='ui-loot-45acp' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-45acp'></div> <div class='tooltip-description'><span data-l10n='game-45acp-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(121,0,255,0.75)'></div> </div> <div id='ui-loot-556mm' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-556mm'></div> <div class='tooltip-description'><span data-l10n='game-556mm-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(3,123,0,0.75)'></div> </div> <div id='ui-loot-40mm' class='ui-outline-hover ui-ammo tooltip'> <div class='tooltip-text click-through'> <div class='tooltip-title' data-l10n='game-40mm'></div> <div class='tooltip-description'><span data-l10n='game-40mm-tooltip'></span></div> </div> <div class='ui-loot-count'>0</div> <img class='ui-loot-image' src=''></img> <div class='ui-loot-overlay' style='background: rgba(12,221,171,0.75)'></div> </div> </div> <div id='ui-emote-button'></div> </div> <div id='ui-top-left' class='js-ui-hud-show click-through'> <div id='ui-team' class='js-ui-mobile-map-hidden'> <div class='ui-team-member ui-bg-standard' data-id='0'> <div class='ui-team-member-name'></div> <div class='ui-team-member-color ui-background-yellow'></div> <div class='ui-team-member-status'></div> <div class='ui-team-member-health'> <div class='ui-bar-inner ui-health-actual'></div> </div> </div> <div class='ui-team-member ui-bg-standard' data-id='1'> <div class='ui-team-member-name'></div> <div class='ui-team-member-color ui-background-purple'></div> <div class='ui-team-member-status'></div> <div class='ui-team-member-health'> <div class='ui-bar-inner ui-health-actual'></div> </div> </div> <div class='ui-team-member ui-bg-standard' data-id='2'> <div class='ui-team-member-name'></div> <div class='ui-team-member-color ui-background-cyan'></div> <div class='ui-team-member-status'></div> <div class='ui-team-member-health'> <div class='ui-bar-inner ui-health-actual'></div> </div> </div> <div class='ui-team-member ui-bg-standard' data-id='3'> <div class='ui-team-member-name'></div> <div class='ui-team-member-color ui-background-orange'></div> <div class='ui-team-member-status'></div> <div class='ui-team-member-health'> <div class='ui-bar-inner ui-health-actual'></div> </div> </div> </div> </div> <div id='ui-map-wrapper' class='ui-map-wrapper-desktop click-through'> <div id='ui-map-container'> <div id='ui-map-info' class='js-ui-map-hidden js-ui-hud-show'> <div id='ui-gas-icon' class='gas-icon'></div> <div id='ui-gas-timer'></div> </div> <div id='ui-spec-counter' class='js-ui-map-hidden js-ui-hud-show'> <div id='ui-spec-counter-icon'></div> <div id='ui-spec-counter-number'></div> </div> <div id='ui-settings-container-desktop' class='js-ui-desktop-map-hidden'> <div id='ui-map-expand-desktop' class='ui-map-expand ui-settings-button'> <img id='mag-glass-white' src=''></img> </div> <div id='ui-map-minimize' class='ui-settings-button js-ui-map-hidden'> <img id='ui-minimize-img' src=''></img> </div> </div> <div id='ui-settings-container-mobile' class='js-ui-mobile-map-hidden'> <div id='ui-alive-info'> <div id='ui-alive-icon' class='ui-map-icon alive-icon'></div> <div id='ui-map-counter-default' class='js-ui-players-alive'>0</div> <div id='ui-map-counter-faction'> <span class='ui-players-alive-red js-ui-players-alive-red'>0</span>:<span class='ui-players-alive-blue js-ui-players-alive-blue'>0</span> </div> </div> <div id='ui-map-expand-mobile' class='ui-map-expand ui-settings-button'></div> </div> </div> </div> <div id='ui-menu-display' class='ui-settings-button prop-event'></div> <div id='ui-kill-leader-container'> <div id='ui-kill-leader-wrapper' class='js-ui-map-hidden js-ui-hud-show hide-on-mobile'> <div id='ui-kill-leader-name'>Waiting for new leader</div> <div id='ui-kill-leader-icon'></div> <div id='ui-kill-leader-count'>0</div> </div> </div> <div id='ui-killfeed-wrapper'> <div id='ui-killfeed' class='js-ui-map-hidden js-ui-hud-show'> <div id='ui-killfeed-contents'></div> </div> </div> <div id='ui-leaderboard-wrapper'> <div id='ui-leaderboard' class='js-ui-hud-show'> <div id='ui-leaderboard-alive'> <span class='ui-players-alive js-ui-players-alive'>0</span> </div> <div id='ui-leaderboard-alive-faction'> <span class='ui-players-alive-red js-ui-players-alive-red'>0</span> <span class='ui-players-alive-blue js-ui-players-alive-blue'>0</span> </div> <div class='ui-leaderboard-header' data-l10n='game-alive'>Alive</div> </div> <div id='ui-kill-counter-wrapper' class='js-ui-map-show'> <div id='ui-kill-counter'> <span class='ui-player-kills js-ui-player-kills'>0</span> </div> <div class='ui-kill-counter-header' data-l10n='game-kills'>Kills</div> </div> </div> <div id='ui-top-center-scopes-wrapper'> <div id='ui-top-center-scopes' class='click-through js-ui-map-hidden'> <div id='ui-scope-1xscope' class='ui-scope ui-zoom'> <div class='ui-zoom-text'> <div class='ui-zoom-level'>1<span class='ui-zoom-append'>x</span></div> </div> </div> <div id='ui-scope-2xscope' class='ui-scope ui-zoom ui-outline-hover'> <div class='ui-zoom-text'> <div class='ui-zoom-level'>2<span class='ui-zoom-append'>x</span></div> </div> </div> <div id='ui-scope-4xscope' class='ui-scope ui-zoom ui-outline-hover'> <div class='ui-zoom-text'> <div class='ui-zoom-level'>4<span class='ui-zoom-append'>x</span></div> </div> </div> <div id='ui-scope-8xscope' class='ui-scope ui-zoom ui-outline-hover'> <div class='ui-zoom-text'> <div class='ui-zoom-level'>8<span class='ui-zoom-append'>x</span></div> </div> </div> <div id='ui-scope-15xscope' class='ui-scope ui-zoom ui-outline-hover'> <div class='ui-zoom-text'> <div class='ui-zoom-level'>15<span class='ui-zoom-append'>x</span></div> </div> </div> </div> </div> <div id='ui-top-center' class='js-ui-map-hidden js-ui-hud-show click-through'> <div id='ui-waiting-text' class='top-center-text'><span data-l10n='game-waiting-for-players'>Waiting for players</span>...</div> <div id='ui-spectate-text' class='top-center-text ui-spectate-mode'> <div class='spectate-text spectate-desc' data-l10n='game-spectating'>Spectating</div> <div id='spectate-player' class='spectate-text'></div> </div> </div> <div id='ui-upper-center' class='click-through'> <div id='ui-announcement'></div> </div> <div id='ui-upper-center-1' class='click-through'> <div id='ui-pickup-notification'> <div id='ui-pickup-description'>Item picked up</div> </div> </div> <div id='ui-lower-center' class='js-ui-map-hidden js-ui-hud-show click-through'> <div id='ui-interaction'> <div id='ui-interaction-press'></div> <div id='ui-interaction-outer'> <div id='ui-interaction-description'></div> </div> </div> </div> <div id='ui-bottom-center-2' class='click-through'> <div id='ui-pickup-message' class='notify-message'></div> <div id='ui-perk-message-wrapper' class='notify-message'> <div id='ui-perk-message-image-wrapper'> <div id='ui-perk-message-image-icon'></div> </div> <div id='ui-perk-message-name' class='notify-message'></div> <div id='ui-perk-message-acquired' class='notify-message'></div> </div> </div> <div id='ui-equipped-ammo-wrapper' class='js-ui-map-hidden js-ui-hud-show'> <div id='ui-equipped-ammo'> <div id='ui-bullet-counter'> <div id='ui-current-clip'>0</div> <div id='ui-remaining-ammo'>0</div> <div id='ui-reload-button-container'> <div id='ui-reload-button'></div> </div> </div> </div> </div> <div id='ui-bottom-center-0' class='click-through js-ui-map-hidden js-ui-hud-show'> <div id='ui-boost-counter'> <div class='ui-boost-base' id='ui-boost-counter-0'> <div class='ui-bar-inner'></div> </div> <div class='ui-boost-base' id='ui-boost-counter-1'> <div class='ui-bar-inner'></div> </div> <div class='ui-boost-base' id='ui-boost-counter-2'> <div class='ui-bar-inner'></div> </div> <div class='ui-boost-base' id='ui-boost-counter-3'> <div class='ui-bar-inner'></div> </div> </div> <div id='ui-health-counter'> <div id='ui-health-flair-left' class='ui-health-flair'></div> <div id='ui-health-flair-right' class='ui-health-flair'></div> <div id='ui-health-container'> <div class='ui-bar-inner' id='ui-health-actual'></div> <div class='ui-bar-inner' id='ui-health-depleted'></div> </div> </div> </div> <div id='ui-bottom-center-left' class='js-ui-map-hidden'> <div id='ui-perk-0' class='ui-armor-counter tooltip-perk ui-outline-hover'> <div class='tooltip-text'> <div class='tooltip-title'></div> <div class='tooltip-desc'></div> </div> <img class='ui-armor-image ui-loot-image' src=''></img> </div> <div id='ui-perk-1' class='ui-armor-counter tooltip-perk ui-outline-hover'> <div class='tooltip-text'> <div class='tooltip-title'></div> <div class='tooltip-desc'></div> </div> <img class='ui-armor-image ui-loot-image' src=''></img> </div> <div id='ui-perk-2' class='ui-armor-counter tooltip-perk ui-outline-hover'> <div class='tooltip-text'> <div class='tooltip-title'></div> <div class='tooltip-desc'></div> </div> <img class='ui-armor-image ui-loot-image' src=''></img> </div> </div> <div id='ui-bottom-center-right' class='js-ui-map-hidden'> <div id='ui-armor-helmet' class='ui-armor-counter ui-outline-hover'> <div class='ui-armor-counter-inner'></div> <div class='ui-armor-level'></div> <img class='ui-armor-image ui-loot-image' src=''></img> </div> <div id='ui-armor-chest' class='ui-armor-counter ui-outline-hover'> <div class='ui-armor-counter-inner'></div> <div class='ui-armor-level'></div> <img class='ui-armor-image ui-loot-image' src=''></img> </div> <div id='ui-armor-backpack' class='ui-armor-counter'> <div class='ui-armor-counter-inner'></div> <div class='ui-armor-level'></div> <img class='ui-armor-image ui-loot-image' src=''></img> </div> </div> <div id='ui-bottom-right' class='js-ui-map-hidden'> <div id='ui-weapon-container'> <div class='ui-weapon-info'> <div class='ui-weapon-switch ui-outline-hover' id='ui-weapon-id-1' data-slot='1'> <div class='ui-weapon-name'></div> <div class='ui-weapon-number'>1</div> <img class='ui-weapon-image' src=''></img> </div> </div> <div class='ui-weapon-info'> <div class='ui-weapon-switch ui-outline-hover' id='ui-weapon-id-2' data-slot='2'> <div class='ui-weapon-name'></div> <div class='ui-weapon-number'>2</div> <img class='ui-weapon-image' src=''></img> </div> </div> <div class='ui-weapon-info'> <div class='ui-weapon-switch ui-outline-hover' id='ui-weapon-id-3'> <div class='ui-weapon-name'></div> <div class='ui-weapon-number'>3</div> <img class='ui-weapon-image' src=''></img> </div> </div> <div class='ui-weapon-info'> <div class='ui-weapon-switch ui-outline-hover' id='ui-weapon-id-4'> <div class='ui-weapon-name'></div> <div class='ui-weapon-number'>4</div> <div class='ui-weapon-exp ui-weapon-ammo-counter'>0</div> <img class='ui-weapon-image' src=''></img> </div> </div> </div> </div> <div id='ui-spectate-options-wrapper'> <div id='ui-spectate-options' class='ui-spectate-mode js-ui-hud-show click-through'> <div id='ui-spectate-buttons' class='ui-bg-standard'> <a class='menu-option btn-darken' id='btn-spectate-next-player' data-l10n='game-next-teammate'>Next Teammate</a> <a class='menu-option btn-darken' id='btn-spectate-prev-player' data-l10n='game-previous-teammate'>Previous Teammate</a> <a class='menu-option btn-darken' id='btn-spectate-view-stats' data-l10n='game-view-match-stats'>View Match Stats</a> <a class='menu-option btn-darken btn-quit' id='btn-spectate-quit' data-l10n='game-leave-game'>Leave Game</a> </div> <div id='ui-spectate-stats' class='ui-bg-standard'> <div id='ui-spectate-stats-header' data-l10n='game-your-results'>Your Results</div> <table id='ui-spectate-stats-table'> <tbody id='ui-spectate-stats-data'> </tbody> </table> </div> </div> </div> <div id='ui-bottom-center-1' class='click-through'> <div id='ui-kills'> <div id='ui-kill-text'></div> <div id='ui-kill-count'></div> </div> </div> </div> <div id='ui-stats'> <div id='ui-stats-bg'></div> <div id='ui-stats-contents'> <div id='ui-stats-contents-inner'> <div id='ui-stats-header'></div> <div id='ui-stats-info-box'></div> <div id='ui-stats-options'></div> <div id='ui-stats-logo'></div> </div> <div id='ui-stats-ad-container-desktop' class='ui-stats-ad-container'> <div id='surviv-io_300x250_2'></div> </div> <div id='ui-stats-ad-container-mobile' class='ui-stats-ad-container'> <div id='surviv-io_300x250_mobile_2'></div> </div> </div> </div> <div class='ui-stats-adblock surviv-shirts'> <a class='surviv-shirts-link' href='/~/https://www.amazon.com/s?rh=n%3A7141123011%2Cp_4%3Asurviv.io&ref=w_bl_sl_s_ap_web_7141123011' target="_blank"></a> </div> <div class='ui-stats-adblock adblock-plea'> <span>Please consider supporting us by disabling your adblocker.</span> </div> </div> <div id='start-menu-wrapper'> <div id='safari-margin'></div> <div id='background'> <div id='start-overlay'></div> </div> <div id='event-modal'> <div id='modal-container'> <p id='modal-header' data-l10n='index-modal-test'>(HEADER TEXT)</p> <img id='modal-img-1'> <div id='modal-content'> <img id='modal-img-2'> <p id='modal-text' data-l10n='event-desc'>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Tincidunt dui ut ornare lectus sit amet est.</p> </div> <button class='close' id='modal-btn' data-l10n='modal-btn-txt' type='button'>(BUTTON TEXT)</button> </div> </div> <div id='start-main'> <div id='start-top-left'> <div id='btn-hamburger' class='icon-hamburger'></div> <div id='start-top-left-desktop'> <div id='featured-streamers'> <div class='streaming-header'> <div id='streaming-header-title' data-l10n='index-streaming-live'>Streaming Live!</div> <div id='streaming-icon'></div> </div> <div class='streamer-list'></div> <div id='featured-streamer-template'> <a href='' target='_blank' class='btn-streamer btn-darken'></a> </div> </div> <div id='featured-youtuber'> <div class='youtube-header'> <div id='youtube-header-title' data-l10n='index-featured-youtuber'>Featured YouTuber</div> </div> <a href='' target='_blank' class='btn-youtuber btn-darken'></a> </div> </div> </div> <!-- Accounts Modals --> <div id='modal-account-name-change' class='modal modal-account'> <div class='modal-content modal-close'> <div class='modal-header modal-header-name'> <span class='close close-corner'></span> <h2 id='modal-account-name-title' data-l10n='index-create-account'>Create Account</h2> </div> <div class='modal-body modal-body-name'> <div class='modal-settings-item'> <p id='modal-account-name-desc' class='modal-body-text' data-l10n='index-set-account-name'>Set your account name:</p> <div id='modal-body-warning'></div> <input type='text' class='menu-option player-name-input' tabindex='0' placeholder='Enter name' id='modal-account-name-input' maxlength='16' /> </div> </div> <div class='modal-footer modal-footer-name modal-footer-round'> <h3 id='modal-account-name-finish' class='finish' data-l10n='index-finish'>Finish</h3> </div> </div> </div> <div id='modal-account-reset-stats' class='modal modal-account'> <div class='modal-content modal-close'> <div class='modal-header modal-header-reset-stats'> <span class='close close-corner'></span> <h2 id='modal-account-name-title' data-l10n='index-reset-stats'>Reset Stats</h2> </div> <div class='modal-body modal-body-reset-stats'> <div class='modal-settings-item'> <p id='modal-account-reset-stats-desc' class='modal-body-text' data-l10n='index-reset-stats-desc'>Enter "RESET STATS" to reset your stats:</p> <p id='modal-account-reset-stats-desc-2' class='modal-body-text' data-l10n='index-reset-stats-desc-2'>(This does not reset pass progress.)</p> <input type='text' class='menu-option player-name-input' tabindex='0' placeholder='' id='modal-account-reset-stats-input' maxlength='16' /> </div> </div> <div class='modal-footer modal-footer-reset-stats modal-footer-round'> <h3 id='modal-account-reset-stats-finish' class='finish' data-l10n='index-confirm'>Confirm</h3> </div> </div> </div> <div id='modal-account-delete' class='modal modal-account'> <div class='modal-content modal-close'> <div class='modal-header modal-header-delete'> <span class='close close-corner'></span> <h2 id='modal-account-name-title' data-l10n='index-delete-account'>Delete Account</h2> </div> <div class='modal-body modal-body-delete'> <div class='modal-settings-item'> <p id='modal-account-delete-desc' class='modal-body-text' data-l10n='index-delete-account-desc'>Enter "DELETE" to delete your account:</p> <input type='text' class='menu-option player-name-input' tabindex='0' placeholder='' id='modal-account-delete-input' maxlength='16' /> </div> </div> <div class='modal-footer modal-footer-delete modal-footer-round'> <h3 id='modal-account-delete-finish' class='finish' data-l10n='index-confirm'>Confirm</h3> </div> </div> </div> <!-- Accounts Mobile --> <div id='modal-mobile-account' class='modal'> <div class='modal-content modal-close'> <div class='modal-header'> <span class='close close-corner'></span> <h2 data-l10n='index-account' data-l10n='index-account'>Account</h2> </div> <div id='modal-mobile-account-body'> <div class='account-buttons-settings account-buttons-wrapper account-block-arrow modal-close'> <div class='account-buttons'> <div class='account-stats-link btn-player-stats-link menu-option btn-darken btn-standard ' data-l10n='index-my-stats'>My Stats</div> <div class='btn-account-link btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-link-account'>Link Account</div> <div class='btn-account-change-name btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-change-account-name'>Change Account Name</div> <div class='btn-account-reset-stats btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-reset-stats'>Reset Stats</div> <div class='btn-account-delete btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-delete-account'>Delete Account</div> <div class='btn-account-logout btn-account-grey menu-option btn-darken btn-standard' data-l10n='index-log-out'>Log Out</div> </div> </div> <div id='account-login-options-mobile' class='account-buttons-link-account account-buttons-wrapper account-block-arrow modal-close'> <div class='login-options-content'></div> </div> </div> </div> </div> <!-- Accounts --> <div id='start-top-right'> <div class='account-block'> <div class='account-details-top'> <div class="account-details-top-buttons"> <div class="account-details-button-wrapper account-details-button-loadout menu-option btn-darken-alt"> <div class='account-details-button'> <div id='loadout-alert-main' class='account-alert-main account-alert'></div> <div class='account-link account-loadout-link'> <span data-l10n='index-loadout'>Loadout</span> </div> </div> </div> <div class="account-details-button-wrapper account-details-link-out menu-option btn-darken hide-on-mobile"> <div class='account-details-button'> <div class='account-link account-stats-link'><span data-l10n='index-my-stats'>My Stats</span></div> </div> </div> <div class="account-details-button-wrapper account-details-link-out menu-option btn-darken hide-on-mobile"> <div class='account-details-button'> <div class='account-link account-leaderboard-link'><span data-l10n='index-leaderboards'>Leaderboards</span></div> </div> </div> </div> </div> <div class='account-overview'> <div class="account-details-user account-details-block"> <div class="account-details"> <div class="account-avatar"></div> <div id="account-login" class="account-player-name account-name account-name-user" data-l10n='index-log-in-desc'>Log In / Create Account</div> <div id="account-player-name" class="account-player-name account-name account-name-user" style="display:none"></div> <div class="account-loading-container"> <div class="account-loading"></div> </div> </div> </div> </div> <div class='account-buttons-settings account-buttons-wrapper account-block-arrow modal-close hide-on-mobile'> <div class='account-buttons'> <div class='btn-account-link btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-link-account'>Link Account</div> <div class='btn-account-change-name btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-change-account-name'>Change Account Name</div> <div class='btn-account-reset-stats btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-reset-stats'>Reset Stats</div> <div class='btn-account-delete btn-account-turq menu-option btn-darken btn-standard' data-l10n='index-delete-account'>Delete Account</div> <div class='btn-account-logout btn-account-grey menu-option btn-darken btn-standard' data-l10n='index-log-out'>Log Out</div> </div> </div> <div id='account-login-options' class='account-buttons-link-account account-buttons-wrapper account-block-arrow modal-close hide-on-mobile'> <div class='login-options-content'></div> </div> </div> </div> <div id='start-main-center'> <div id='start-row-header'> <div id='server-warning'></div> </div> <div id='start-row-top'> <div id='start-rotate-reminder' class='menu-column menu-block'> <span>Rotate to landscape for a better experience.</span> </div> <div id='left-column' class='menu-column'> <div id='ad-block-left'> <div class='surviv-shirts'> <a href='/~/https://www.amazon.com/s?rh=n%3A7141123011%2Cp_4%3Asurviv.io&ref=w_bl_sl_s_ap_web_7141123011' target="_blank"></a> </div> <div class='adblock-plea'> <span>Please consider supporting us by disabling your adblocker.</span> </div> <div class='ad-block-med-rect' id='surviv-io_300x250'> </div> </div> <div id='social-share-block-wrapper'> <div id='social-share-block' class='menu-block'> <div class='btn-social-wrapper'> <a href='/~/https://facebook.com/surviviogame' target='_blank' class='btn-social btn-darken btn-facebook'></a> <a href='/~/https://twitter.com/survivio' target='_blank' class='btn-social btn-darken btn-twitter'></a> <a href='/~/https://www.instagram.com/surviviogame/' target='_blank' class='btn-social btn-darken btn-instagram'></a> <a href='/~/https://discord.gg/survivio' target='_blank' class='btn-social btn-darken btn-discord'></a> <a href='/~/https://www.youtube.com/c/survivio?sub_confirmation=1' target='_blank' class='btn-social btn-darken btn-youtube'></a> </div> </div> </div> </div> <div id='start-menu' class='menu-column menu-block'> <div class='play-loading-outer'> <div class='play-loading-inner'> <div class='play-loading-spinner'></div> </div> </div> <div class='play-button-container'> <div id='player-options'> <input type='text' class='menu-option player-name-input' tabindex='0' placeholder='Enter your name here' id='player-name-input-solo' maxlength='16' /> <a class='btn-darken menu-option player-options-btn' id='btn-customize'></a> </div> <select id='server-select-main' class='server-select menu-option btn-hollow btn-hollow-selected'> <optgroup id='server-opts' label='Region' data-l10n='index-region'> <option value='na' data-label='North America' data-l10n='index-north-america'>North America</option> <option value='sa' data-label='South America' data-l10n='index-south-america'>South America</option> <option value='eu' data-label='Europe' data-l10n='index-europe'>Europe</option> <option value='as' data-label='Asia' data-l10n='index-asia'>Asia</option> <option value='kr' data-label='Korea' data-l10n='index-korea'>South Korea</option> </optgroup> </select> <a class='btn-green btn-darken menu-option' id='btn-start-mode-0' data-l10n='index-play-solo'>Play Solo</a> <div id='btns-quick-start'> <a class='btn-green btn-darken menu-option' id='btn-start-mode-1' data-l10n='index-play-duo'>Play Duo</a> <a class='btn-green btn-darken menu-option' id='btn-start-mode-2' data-l10n='index-play-squad'>Play Squad</a> </div> <div class='btns-double-row'> <a class='btn-darken menu-option btn-team-option' id='btn-join-team' data-l10n='index-join-team'>Join Team</a> <a class='btn-darken menu-option btn-team-option' id='btn-create-team' data-l10n='index-create-team'>Create Team</a> </div> <div id='btn-help' class='menu-option btn-darken' data-l10n='index-how-to-play'>How to Play</div> <div id='start-help'> <h1 data-l10n='index-controls'>Controls</h1> <p><span class='help-action' data-l10n='index-movement'></span>: <span class='help-control' data-l10n='index-movement-ctrl'></span></p> <p><span class='help-action' data-l10n='index-aim'></span>: <span class='help-control' data-l10n='index-aim-ctrl'></span></p> <p><span class='help-action' data-l10n='index-punch'></span>/<span class='help-action' data-l10n='index-shoot'></span>: <span class='help-control' data-l10n='index-shoot-ctrl'></span></p> <p><span class='help-action' data-l10n='index-change-weapons'></span>: <span class='help-control' data-l10n='index-change-weapons-ctrl'></span></p> <p class='hide-on-mobile'><span class='help-action' data-l10n='index-stow-weapons'></span>: <span class='help-control' data-l10n='index-stow-weapons-ctrl'></span></p> <p class='hide-on-mobile'><span class='help-action' data-l10n='index-swap-weapons'></span>: <span class='help-control' data-l10n='index-swap-weapons-ctrl'></span></p> <p class='hide-on-mobile'><span class='help-action' data-l10n='index-swap-weapon-slots'></span>: <span class='help-control' data-l10n='index-swap-weapon-slots-ctrl'></span></p> <p><span class='help-action' data-l10n='index-reload'></span>: <span class='help-control' data-l10n='index-reload-ctrl'></span></p> <p><span class='help-action' data-l10n='index-scope-zoom'></span>: <span class='help-control' data-l10n='index-scope-zoom-ctrl'></span></p> <p><span class='help-action' data-l10n='index-pickup'></span>/<span class='help-action' data-l10n='index-loot'></span>/<span class='help-action' data-l10n='index-revive'></span>: <span class='help-control' data-l10n='index-pickup-ctrl'></span></p> <p><span class='help-action' data-l10n='index-use-medical'></span>: <span class='help-control' data-l10n='index-use-medical-ctrl'></span></p> <p><span class='help-action' data-l10n='index-drop-item'></span>: <span class='help-control' data-l10n='index-drop-item-ctrl'></span></p> <p><span class='help-action' data-l10n='index-cancel-action'></span>: <span class='help-control' data-l10n='index-cancel-action-ctrl'></span></p> <p><span class='help-action' data-l10n='index-view-map'></span>: <span class='help-control' data-l10n='index-view-map-ctrl'></span></p> <p class='hide-on-mobile'><span class='help-action' data-l10n='index-toggle-minimap'></span>: <span class='help-control' data-l10n='index-toggle-minimap-ctrl'></span></p> <p><span class='help-action' data-l10n='index-use-ping'></span>: <span class='help-control' data-l10n='index-use-ping-ctrl'></span></p> <p><span class='help-action' data-l10n='index-use-emote'></span>: <span class='help-control' data-l10n='index-use-emote-ctrl'></span></p> <h1 data-l10n='index-how-to-play'>How to Play</h1> <p data-l10n='index-tips-1-desc'>The goal of surviv.io is to be the last player standing. You only live once per game - there is no respawn!</p> <h1 data-l10n='index-tips-2'>2D PUBG</h1> <p data-l10n='index-tips-2-desc'>If you've played other battle royale games like PUBG, Fortnite or H1Z1, then you're already halfway there! Think of surviv.io as 2D PUBG (with slightly less desync and more chicken).</p> <h1 data-l10n='index-tips-3'>Loot and Kill</h1> <p data-l10n='index-tips-3-desc'>You'll begin the game with no items other than a simple backpack. Move around the map to find loot: weapons, ammo, scopes, and medical items. Eliminate other players and you can take their loot!</p> <h1 data-l10n='index-tips-4'>Red = Bad!</h1> <p data-l10n='index-tips-4-desc'>Players aren't the only thing that can hurt you. The deadly red zone will move in from the sides of the map and deal increasingly greater damage if you stand in it. Keep an eye on the map and stay safe.</p> </div> </div> </div> <div id='team-menu' class='menu-column menu-block'> <div class='play-loading-outer'> <div class='play-loading-inner'> <div class='play-loading-spinner'></div> </div> </div> <div class='play-button-container'> <a class='btn-darken menu-option' id='btn-team-leave' data-l10n='index-leave-team'>Leave Team</a> <div id='team-menu-connecting'> <div class='ui-spinner'></div> <div class='team-menu-connecting-text' id='team-menu-joining-text'><span data-l10n='index-joining-team'>Joining team</span> ...</div> <div class='team-menu-connecting-text' id='team-menu-creating-text'><span data-l10n='index-creating-team'>Creating team</span> ...</div> </div> <div id='team-menu-contents'> <div id='team-desc'> <div id='team-desc-text'><span id='invite-link-text' data-l10n='index-invite-link'>Invite link</span>: <span id='team-url'></span> </div> <a id='team-copy-url' class='copy-item btn-darken'></a> <a id='team-hide-url' class='hide-item btn-darken'></a> <div id='team-code-text'><span id='invite-code-text' data-l10n='index-invite-code'>Invite code</span>: <span id='team-code'></span></div> </div> <div id='team-menu-columns'> <div id='team-menu-members' class='team-menu-block'> <div id='team-menu-member-list'></div> </div> <div id='team-menu-options' class='team-menu-block'> <select id='team-server-select' class='btn-hollow btn-hollow-selected server-select menu-option'> <optgroup id='team-server-opts' label='Region'> <option value='na' data-label='North America' data-l10n='index-north-america'>North America</option> <option value='sa' data-label='South America' data-l10n='index-south-america'>South America</option> <option value='eu' data-label='Europe' data-l10n='index-europe'>Europe</option> <option value='as' data-label='Asia' data-l10n='index-asia'>Asia</option> <option value='kr' data-label='Korea' data-l10n='index-korea'>South Korea</option> </optgroup> </select> <div class='team-menu-options-buttons'> <a class='btn-hollow btn-hollow-selected btn-darken team-menu-option btn-team-queue' id='btn-team-queue-mode-1' data-l10n='index-duo'>Duo</a> <a class='btn-hollow btn-hollow-selected btn-darken team-menu-option btn-team-queue' id='btn-team-queue-mode-2' data-l10n='index-squad'>Squad</a> </div> <div class='team-menu-options-buttons'> <a class='btn-hollow btn-hollow-selected btn-darken team-menu-option btn-team-fill' id='btn-team-fill-auto' data-l10n='index-auto-fill'>Auto Fill</a> <a class='btn-hollow btn-darken team-menu-option btn-team-fill' id='btn-team-fill-none' data-l10n='index-no-fill'>No Fill</a> </div> <div id='team-menu-options-start'> <a class='btn-green btn-darken menu-option' id='btn-start-team' data-label='Play' data-l10n='index-play'>Play</a> <div id='msg-wait-reason'></div> </div> </div> </div> </div> </div> </div> <div id='team-mobile-link' class='menu-column menu-block'> <div id='team-mobile-link-desc' class='team-mobile-link-text' data-l10n='index-join-team-help'>Got a team link or code? Paste it here:</div> <div id='team-mobile-link-warning' class='team-mobile-link-text'>Invalid link!</div> <input type='text' class='menu-option' contenteditable="false" tabindex='0' autofocus placeholder='Paste team link or enter code here' id='team-link-input' /> <a class='btn-darken menu-option btn-team-option' id='btn-team-mobile-link-join' data-l10n='index-join-team'>Join Team</a> <a class='btn-darken menu-option' id='btn-team-mobile-link-leave' data-l10n='index-back-to-main'>Back to Main Menu</a> </div> <div id='right-column' class='menu-column'> <div id='pass-wrapper'> <div id='pass-unlock-tooltip'> <div class='tooltip-pass-title'></div> <div class='tooltip-pass-desc'></div> </div> <div class='right-column-toggle news-toggle'> <div class='account-alert'></div> </div> <div id='pass-loading' class='pass-column menu-block'> <div id='pass-loading-spinner'></div> </div> <div id='pass-block' class='pass-column menu-block'> <div id='pass-name'> <span id='pass-name-text'></span> </div> <div id='pass-progress' class=''> <div id='pass-progress-level' class=''></div> <div id='pass-progress-bar' class=''> <div id='pass-progress-bar-fill'></div> <div id='pass-progress-xp'> <span id='pass-progress-xp-current'></span> <span>/</span> <span id='pass-progress-xp-target'></span> <span>XP</span> </div> </div> <div id='pass-progress-unlock-wrapper'> <div id='pass-progress-unlock' class=''> <div id='pass-progress-unlock-image' class=''></div> </div> <div id='pass-progress-unlock-type-wrapper' class=''> <div id='pass-progress-unlock-type-border' class=''> <div id='pass-progress-unlock-type-image' class=''></div> </div> <div id='pass-progress-unlock-overlay' class=''></div> </div> </div> </div> <div id='pass-quest-wrapper' class=''> <div id='pass-locked'> <div id='btn-pass-locked' class='menu-option btn-darken' data-l10n='quest-login-prompt'>Log in to get quests!</div> </div> <div id='pass-quest-0' class='pass-quest'> <div class='pass-quest-timer'></div> <div class='pass-quest-spinner-container'> <div class='pass-quest-spinner'></div> </div> <div class='pass-quest-refresh-prompt'> <div class='pass-quest-refresh-prompt-text' data-l10n='quest-refresh-prompt'>Get a new quest?</div> <div class='pass-quest-refresh-confirm btn-pass-quest-refresh'></div> <div class='pass-quest-refresh-cancel btn-pass-quest-refresh'></div> </div> <div class='pass-quest-info'> <div class='pass-quest-desc'></div> <div class='pass-quest-xp'></div> <div class='pass-quest-refresh'></div> <div class='pass-quest-progress'> <div class='pass-quest-bar'> <div class='pass-quest-bar-fill'></div> </div> <div class='pass-quest-counter'> <span class='pass-quest-counter-current'></span> <span>/</span> <span class='pass-quest-counter-target'></span> </div> </div> </div> </div> <div id='pass-quest-1' class='pass-quest'> <div class='pass-quest-timer'></div> <div class='pass-quest-spinner-container'> <div class='pass-quest-spinner'></div> </div> <div class='pass-quest-refresh-prompt'> <div class='pass-quest-refresh-prompt-text' data-l10n='quest-refresh-prompt'>Get a new quest?</div> <div class='pass-quest-refresh-confirm btn-pass-quest-refresh'></div> <div class='pass-quest-refresh-cancel btn-pass-quest-refresh'></div> </div> <div class='pass-quest-info'> <div class='pass-quest-desc'></div> <div class='pass-quest-xp'></div> <div class='pass-quest-refresh'></div> <div class='pass-quest-progress'> <div class='pass-quest-bar'> <div class='pass-quest-bar-fill'></div> </div> <div class='pass-quest-counter'> <span class='pass-quest-counter-current'></span> <span>/</span> <span class='pass-quest-counter-target'></span> </div> </div> </div> </div> </div> </div> </div> <div id='news-wrapper'> <div class='right-column-toggle pass-toggle'></div> <div id='news-block' class='menu-block'> <div id='news'> <h3 class='news-header'>What's New!</h3> <div id='news-current' data-date='2020-2-24'> <small class='news-date'>February 24, 2020</small> <p class='news-paragraph'><strong>Curveball</strong></p> <p class='news-paragraph'>The <span class='highlight'>Savannah</span> has returned with a new perk to help flush snipers out of position.</p> <p class='news-paragraph'>The <span class='highlight'>Closer Perk</span> throws grenades much farther, allowing you to put Snipers on the move.</p> </div> <div data-date='2020-2-10'> <small class='news-date'>February 10, 2020</small> <p class='news-paragraph'><strong>Keep Your Enemies Closer</strong></p> <p class='news-paragraph'>PARMA recognizes this season of togetherness and generously offers to help rivals resolve their differences. The all new <span class='highlight'>Heart Cannon</span> diffuses damage taken from your frenemies. For groups of future friends, the same effect is achieved with the all-new <span class='highlight'>Heart Grenade</span>.</p> <p class='news-paragraph'>If you do not trust the intentions of your new friends, eat an entire <span class='highlight'>box of chocolates</span> to counter the effect of <span class='highlight'>Heart Weapons</span>.</p> </div> <div data-date='2020-1-27'> <small class='news-date'>January 27, 2020</small> <p class='news-paragraph'><strong>Dodge This</strong></p> <p class='news-paragraph'><span class='highlight'>Woods</span> Mode is back with two new weapons and things are bound to get explosive. The <span class='highlight'>PKM</span> and <span class='highlight'>Hawk 12G</span> join the Woods Map arsenal, along with increased grenade capacity.</p> <p class='news-paragraph'>The <span class='highlight'>PKM</span> packs a punch while balancing mobility and range. Based on the M870 with an added magazine, the <span class='highlight'>Hawk 12G</span>'s ammo capacity of 5 is the same as its parent weapon, the fire delay is faster and fires a tighter spread. </p> </div> <div data-date='2020-1-13'> <small class='news-date'>January 13, 2020</small> <p class='news-paragraph'><strong>Stay frosty</strong></p> <p class='news-paragraph'>Winter has arrived on the Island with new features and is more dangerous than ever, including PARMA's latest item, the <span class='highlight'>Flask</span>.</p> <p class='news-paragraph'>Track your enemy's footprints and use the <span class='highlight'>Snow Fox</span> perk to cover up your footprints. Be sure to keep moving or take freezing damage. Flasks and the <span class='highlight'>Polar Bear</span> perk keep you from freezing. And watch out for ice. It's slippery.</p> </div> <div data-date='2019-12-30'> <small class='news-date'>December 30, 2019</small> <p class='news-paragraph'><strong>Free Fryer</strong></p> <p class='news-paragraph'>PARMA's FSTMS division is pleased to introduce the next generation in starch-based modern warfare: the <span class='highlight'>spud gun</span>.</p> <p class='news-paragraph'>Officially designated the SMG-8 (Spud Missile Generator), the spud gun uses a proprietary breech-to-muzzle heat expander to fry and propel wedge-shaped projectiles at tremendous speeds. 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Image Classifier Going forward, AI algorithms will be incorporated into more and more everyday applications. For example, you might want to include an image classifier in a smartphone app. To do this, you'd use a deep learning model trained on hundreds of thousands of images as part of the overall application architecture. A large part of software development in the future will be using these types of models as common parts of applications. In this project, you'll train an image classifier to recognize different species of flowers. You can imagine using something like this in a phone app that tells you the name of the flower your camera is looking at. In practice, you'd train this classifier, then export it for use in your application. We'll be using this dataset of 102 flower categories. When you've completed this project, you'll have an application that can be trained on any set of labelled images. Here your network will be learning about flowers and end up as a command line application. But, what you do with your new skills depends on your imagination and effort in building a dataset. This is the final Project of the Udacity AI with Python Nanodegree Prerequisites The Code is written in Python 3.6.5 . If you don't have Python installed you can find it here. If you are using a lower version of Python you can upgrade using the pip package, ensuring you have the latest version of pip. To install pip run in the command Line python -m ensurepip -- default-pip to upgrade it python -m pip install -- upgrade pip setuptools wheel to upgrade Python pip install python -- upgrade Additional Packages that are required are: Numpy, Pandas, MatplotLib, Pytorch, PIL and json. You can donwload them using pip pip install numpy pandas matplotlib pil or conda conda install numpy pandas matplotlib pil In order to intall Pytorch head over to the Pytorch site select your specs and follow the instructions given. Viewing the Jyputer Notebook In order to better view and work on the jupyter Notebook I encourage you to use nbviewer . You can simply copy and paste the link to this website and you will be able to edit it without any problem. Alternatively you can clone the repository using git clone https://github.com/fotisk07/Image-Classifier/ then in the command Line type, after you have downloaded jupyter notebook type jupyter notebook locate the notebook and run it. Command Line Application Train a new network on a data set with train.py Basic Usage : python train.py data_directory Prints out current epoch, training loss, validation loss, and validation accuracy as the netowrk trains Options: Set direcotry to save checkpoints: python train.py data_dor --save_dir save_directory Choose arcitecture (alexnet, densenet121 or vgg16 available): pytnon train.py data_dir --arch "vgg16" Set hyperparameters: python train.py data_dir --learning_rate 0.001 --hidden_layer1 120 --epochs 20 Use GPU for training: python train.py data_dir --gpu gpu Predict flower name from an image with predict.py along with the probability of that name. That is you'll pass in a single image /path/to/image and return the flower name and class probability Basic usage: python predict.py /path/to/image checkpoint Options: Return top K most likely classes: python predict.py input checkpoint ---top_k 3 Use a mapping of categories to real names: python predict.py input checkpoint --category_names cat_To_name.json Use GPU for inference: python predict.py input checkpoint --gpu Json file In order for the network to print out the name of the flower a .json file is required. If you aren't familiar with json you can find information here. By using a .json file the data can be sorted into folders with numbers and those numbers will correspond to specific names specified in the .json file. Data and the json file The data used specifically for this assignemnt are a flower database are not provided in the repository as it's larger than what github allows. Nevertheless, feel free to create your own databases and train the model on them to use with your own projects. The structure of your data should be the following: The data need to comprised of 3 folders, test, train and validate. Generally the proportions should be 70% training 10% validate and 20% test. Inside the train, test and validate folders there should be folders bearing a specific number which corresponds to a specific category, clarified in the json file. For example if we have the image a.jpj and it is a rose it could be in a path like this /test/5/a.jpg and json file would be like this {...5:"rose",...}. Make sure to include a lot of photos of your catagories (more than 10) with different angles and different lighting conditions in order for the network to generalize better. GPU As the network makes use of a sophisticated deep convolutional neural network the training process is impossible to be done by a common laptop. In order to train your models to your local machine you have three options Cuda -- If you have an NVIDIA GPU then you can install CUDA from here. With Cuda you will be able to train your model however the process will still be time consuming Cloud Services -- There are many paid cloud services that let you train your models like AWS or Google Cloud Coogle Colab -- Google Colab gives you free access to a tesla K80 GPU for 12 hours at a time. Once 12 hours have ellapsed you can just reload and continue! The only limitation is that you have to upload the data to Google Drive and if the dataset is massive you may run out of space. However, once a model is trained then a normal CPU can be used for the predict.py file and you will have an answer within some seconds. Hyperparameters As you can see you have a wide selection of hyperparameters available and you can get even more by making small modifications to the code. Thus it may seem overly complicated to choose the right ones especially if the training needs at least 15 minutes to be completed. So here are some hints: By increasing the number of epochs the accuracy of the network on the training set gets better and better however be careful because if you pick a large number of epochs the network won't generalize well, that is to say it will have high accuracy on the training image and low accuracy on the test images. Eg: training for 12 epochs training accuracy: 85% Test accuracy: 82%. Training for 30 epochs training accuracy 95% test accuracy 50%. A big learning rate guarantees that the network will converge fast to a small error but it will constantly overshot A small learning rate guarantees that the network will reach greater accuracies but the learning process will take longer Densenet121 works best for images but the training process takes significantly longer than alexnet or vgg16 *My settings were lr=0.001, dropoup=0.5, epochs= 15 and my test accuracy was 86% with densenet121 as my feature extraction model. Pre-Trained Network The checkpoint.pth file contains the information of a network trained to recognise 102 different species of flowers. I has been trained with specific hyperparameters thus if you don't set them right the network will fail. In order to have a prediction for an image located in the path /path/to/image using my pretrained model you can simply type python predict.py /path/to/image checkpoint.pth Contributing Please read CONTRIBUTING.md for the process for submitting pull requests. Authors Shanmukha Mudigonda - Initial work Udacity - Final Project of the AI with Python Nanodegree

 [](https://search.maven.org/search?q=g:net.openid%20appauth) [](http://javadoc.io/doc/net.openid/appauth) [](https://github.com/openid/AppAuth-Android/actions/workflows/build.yml) [](https://codecov.io/github/openid/AppAuth-Android?branch=master) AppAuth for Android is a client SDK for communicating with [OAuth 2.0](https://tools.ietf.org/html/rfc6749) and [OpenID Connect](http://openid.net/specs/openid-connect-core-1_0.html) providers. It strives to directly map the requests and responses of those specifications, while following the idiomatic style of the implementation language. In addition to mapping the raw protocol flows, convenience methods are available to assist with common tasks like performing an action with fresh tokens. The library follows the best practices set out in [RFC 8252 - OAuth 2.0 for Native Apps](https://tools.ietf.org/html/rfc8252), including using [Custom Tabs](https://developer.chrome.com/multidevice/android/customtabs) for authorization requests. For this reason, `WebView` is explicitly *not* supported due to usability and security reasons. The library also supports the [PKCE](https://tools.ietf.org/html/rfc7636) extension to OAuth which was created to secure authorization codes in public clients when custom URI scheme redirects are used. The library is friendly to other extensions (standard or otherwise) with the ability to handle additional parameters in all protocol requests and responses. A talk providing an overview of using the library for enterprise single sign-on (produced by Google) can be found here: [Enterprise SSO with Chrome Custom Tabs](https://www.youtube.com/watch?v=DdQTXrk6YTk). ## Download AppAuth for Android is available on [MavenCentral](https://search.maven.org/search?q=g:net.openid%20appauth) ```groovy implementation 'net.openid:appauth:<version>' ``` ## Requirements AppAuth supports Android API 16 (Jellybean) and above. Browsers which provide a custom tabs implementation are preferred by the library, but not required. Both Custom URI Schemes (all supported versions of Android) and App Links (Android M / API 23+) can be used with the library. In general, AppAuth can work with any Authorization Server (AS) that supports native apps as documented in [RFC 8252](https://tools.ietf.org/html/rfc8252), either through custom URI scheme redirects, or App Links. AS's that assume all clients are web-based or require clients to maintain confidentiality of the client secrets may not work well. ## Demo app A demo app is contained within this repository. For instructions on how to build and configure this app, see the [demo app readme](https://github.com/openid/AppAuth-Android/blob/master/app/README.md). ## Conceptual overview AppAuth encapsulates the authorization state of the user in the [net.openid.appauth.AuthState](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthState.java) class, and communicates with an authorization server through the use of the [net.openid.appauth.AuthorizationService](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationService.java) class. AuthState is designed to be easily persistable as a JSON string, using the storage mechanism of your choice (e.g. [SharedPreferences](https://developer.android.com/training/basics/data-storage/shared-preferences.html), [sqlite](https://developer.android.com/training/basics/data-storage/databases.html), or even just [in a file](https://developer.android.com/training/basics/data-storage/files.html)). AppAuth provides data classes which are intended to model the OAuth2 specification as closely as possible; this provides the greatest flexibility in interacting with a wide variety of OAuth2 and OpenID Connect implementations. Authorizing the user occurs via the user's web browser, and the request is described using instances of [AuthorizationRequest](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationRequest.java). The request is dispatched using [performAuthorizationRequest()](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationService.java#L159) on an AuthorizationService instance, and the response (an [AuthorizationResponse](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationResponse.java) instance) will be dispatched to the activity of your choice, expressed via an Intent. Token requests, such as obtaining a new access token using a refresh token, follow a similar pattern: [TokenRequest](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/TokenRequest.java) instances are dispatched using [performTokenRequest()](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationService.java#L252) on an AuthorizationService instance, and a [TokenResponse](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/TokenResponse.java) instance is returned via a callback. Responses can be provided to the [update()](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthState.java#L367) methods on AuthState in order to track and persist changes to the authorization state. Once in an authorized state, the [performActionWithFreshTokens()](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthState.java#L449) method on AuthState can be used to automatically refresh access tokens as necessary before performing actions that require valid tokens. ## Implementing the authorization code flow It is recommended that native apps use the [authorization code](https://tools.ietf.org/html/rfc6749#section-1.3.1) flow with a public client to gain authorization to access user data. This has the primary advantage for native clients that the authorization flow, which must occur in a browser, only needs to be performed once. This flow is effectively composed of four stages: 1. Discovering or specifying the endpoints to interact with the provider. 2. Authorizing the user, via a browser, in order to obtain an authorization code. 3. Exchanging the authorization code with the authorization server, to obtain a refresh token and/or ID token. 4. Using access tokens derived from the refresh token to interact with a resource server for further access to user data. At each step of the process, an AuthState instance can (optionally) be updated with the result to help with tracking the state of the flow. ### Authorization service configuration First, AppAuth must be instructed how to interact with the authorization service. This can be done either by directly creating an [AuthorizationServiceConfiguration](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationServiceConfiguration.java#L102) instance, or by retrieving an OpenID Connect discovery document. Directly specifying an AuthorizationServiceConfiguration involves providing the URIs of the authorization endpoint and token endpoint, and optionally a dynamic client registration endpoint (see "Dynamic client registration" for more info): ```java AuthorizationServiceConfiguration serviceConfig = new AuthorizationServiceConfiguration( Uri.parse("https://idp.example.com/auth"), // authorization endpoint Uri.parse("https://idp.example.com/token")); // token endpoint ``` Where available, using an OpenID Connect discovery document is preferable: ```java AuthorizationServiceConfiguration.fetchFromIssuer( Uri.parse("https://idp.example.com"), new AuthorizationServiceConfiguration.RetrieveConfigurationCallback() { public void onFetchConfigurationCompleted( @Nullable AuthorizationServiceConfiguration serviceConfiguration, @Nullable AuthorizationException ex) { if (ex != null) { Log.e(TAG, "failed to fetch configuration"); return; } // use serviceConfiguration as needed } }); ``` This will attempt to download a discovery document from the standard location under this base URI, `https://idp.example.com/.well-known/openid-configuration`. If the discovery document for your IDP is in some other non-standard location, you can instead provide the full URI as follows: ```java AuthorizationServiceConfiguration.fetchFromUrl( Uri.parse("https://idp.example.com/exampletenant/openid-config"), new AuthorizationServiceConfiguration.RetrieveConfigurationCallback() { ... } }); ``` If desired, this configuration can be used to seed an AuthState instance, to persist the configuration easily: ```java AuthState authState = new AuthState(serviceConfig); ``` ### Obtaining an authorization code An authorization code can now be acquired by constructing an AuthorizationRequest, using its Builder. In AppAuth, the builders for each data class accept the mandatory parameters via the builder constructor: ```java AuthorizationRequest.Builder authRequestBuilder = new AuthorizationRequest.Builder( serviceConfig, // the authorization service configuration MY_CLIENT_ID, // the client ID, typically pre-registered and static ResponseTypeValues.CODE, // the response_type value: we want a code MY_REDIRECT_URI); // the redirect URI to which the auth response is sent ``` Other optional parameters, such as the OAuth2 [scope string](https://tools.ietf.org/html/rfc6749#section-3.3) or OpenID Connect [login hint](http://openid.net/specs/openid-connect-core-1_0.html#rfc.section.3.1.2.1) are specified through set methods on the builder: ```java AuthorizationRequest authRequest = authRequestBuilder .setScope("openid email profile https://idp.example.com/custom-scope") .setLoginHint("jdoe@user.example.com") .build(); ``` This request can then be dispatched using one of two approaches. a `startActivityForResult` call using an Intent returned from the `AuthorizationService`, or by calling `performAuthorizationRequest` and providing pending intent for completion and cancelation handling activities. The `startActivityForResult` approach is simpler to use but may require more processing of the result: ```java private void doAuthorization() { AuthorizationService authService = new AuthorizationService(this); Intent authIntent = authService.getAuthorizationRequestIntent(authRequest); startActivityForResult(authIntent, RC_AUTH); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == RC_AUTH) { AuthorizationResponse resp = AuthorizationResponse.fromIntent(data); AuthorizationException ex = AuthorizationException.fromIntent(data); // ... process the response or exception ... } else { // ... } } ``` If instead you wish to directly transition to another activity on completion or cancelation, you can use `performAuthorizationRequest`: ```java AuthorizationService authService = new AuthorizationService(this); authService.performAuthorizationRequest( authRequest, PendingIntent.getActivity(this, 0, new Intent(this, MyAuthCompleteActivity.class), 0), PendingIntent.getActivity(this, 0, new Intent(this, MyAuthCanceledActivity.class), 0)); ``` The intents may be customized to carry any additional data or flags required for the correct handling of the authorization response. #### Capturing the authorization redirect Once the authorization flow is completed in the browser, the authorization service will redirect to a URI specified as part of the authorization request, providing the response via query parameters. In order for your app to capture this response, it must register with the Android OS as a handler for this redirect URI. We recommend using a custom scheme based redirect URI (i.e. those of form `my.scheme:/path`), as this is the most widely supported across all versions of Android. To avoid conflicts with other apps, it is recommended to configure a distinct scheme using "reverse domain name notation". This can either match your service web domain (in reverse) e.g. `com.example.service` or your package name `com.example.app` or be something completely new as long as it's distinct enough. Using the package name of your app is quite common but it's not always possible if it contains illegal characters for URI schemes (like underscores) or if you already have another handler for that scheme - so just use something else. When a custom scheme is used, AppAuth can be easily configured to capture all redirects using this custom scheme through a manifest placeholder: ```groovy android.defaultConfig.manifestPlaceholders = [ 'appAuthRedirectScheme': 'com.example.app' ] ``` Alternatively, the redirect URI can be directly configured by adding an intent-filter for AppAuth's RedirectUriReceiverActivity to your AndroidManifest.xml: ```xml <activity android:name="net.openid.appauth.RedirectUriReceiverActivity" tools:node="replace"> <intent-filter> <action android:name="android.intent.action.VIEW"/> <category android:name="android.intent.category.DEFAULT"/> <category android:name="android.intent.category.BROWSABLE"/> <data android:scheme="com.example.app"/> </intent-filter> </activity> ``` If an HTTPS redirect URI is required instead of a custom scheme, the same approach (modifying your AndroidManifest.xml) is used: ```xml <activity android:name="net.openid.appauth.RedirectUriReceiverActivity" tools:node="replace"> <intent-filter> <action android:name="android.intent.action.VIEW"/> <category android:name="android.intent.category.DEFAULT"/> <category android:name="android.intent.category.BROWSABLE"/> <data android:scheme="https" android:host="app.example.com" android:path="/oauth2redirect"/> </intent-filter> </activity> ``` HTTPS redirects can be secured by configuring the redirect URI as an [app link](https://developer.android.com/training/app-links/index.html) in Android M and above. We recommend that a fallback page be configured at the same address to forward authorization responses to your app via a custom scheme, for older Android devices. #### Handling the authorization response Upon completion of the authorization flow, the completion Intent provided to performAuthorizationRequest will be triggered. The authorization response is provided to this activity via Intent extra data, which can be extracted using the `fromIntent()` methods on AuthorizationResponse and AuthorizationException respectively: ```java public void onCreate(Bundle b) { AuthorizationResponse resp = AuthorizationResponse.fromIntent(getIntent()); AuthorizationException ex = AuthorizationException.fromIntent(getIntent()); if (resp != null) { // authorization completed } else { // authorization failed, check ex for more details } // ... } ``` The response can be provided to the AuthState instance for easy persistence and further processing: ``` authState.update(resp, ex); ``` If the full redirect URI is required in order to extract additional information that AppAuth does not provide, this is also provided to your activity: ```java public void onCreate(Bundle b) { // ... Uri redirectUri = getIntent().getData(); // ... } ``` ### Exchanging the authorization code Given a successful authorization response carrying an authorization code, a token request can be made to exchange the code for a refresh token: ```java authService.performTokenRequest( resp.createTokenExchangeRequest(), new AuthorizationService.TokenResponseCallback() { @Override public void onTokenRequestCompleted( TokenResponse resp, AuthorizationException ex) { if (resp != null) { // exchange succeeded } else { // authorization failed, check ex for more details } } }); ``` The token response can also be used to update an AuthState instance: ```java authState.update(resp, ex); ``` ### Using access tokens Finally, the retrieved access token can be used to interact with a resource server. This can be done directly, by extracting the access token from a token response. However, in most cases, it is simpler to use the `performActionWithFreshTokens` utility method provided by AuthState: ```java authState.performActionWithFreshTokens(service, new AuthStateAction() { @Override public void execute( String accessToken, String idToken, AuthorizationException ex) { if (ex != null) { // negotiation for fresh tokens failed, check ex for more details return; } // use the access token to do something ... } }); ``` This also updates the AuthState object with current access, id, and refresh tokens. If you are storing your AuthState in persistent storage, you should write the updated copy in the callback to this method. ### Ending current session Given you have a logged in session and you want to end it. In that case you need to get: - `AuthorizationServiceConfiguration` - valid Open Id Token that you should get after authentication - End of session URI that should be provided within you OpenId service config First you have to build EndSessionRequest ```java EndSessionRequest endSessionRequest = new EndSessionRequest.Builder(authorizationServiceConfiguration) .setIdTokenHint(idToken) .setPostLogoutRedirectUri(endSessionRedirectUri) .build(); ``` This request can then be dispatched using one of two approaches. a `startActivityForResult` call using an Intent returned from the `AuthorizationService`, or by calling `performEndSessionRequest` and providing pending intent for completion and cancelation handling activities. The startActivityForResult approach is simpler to use but may require more processing of the result: ```java private void endSession() { AuthorizationService authService = new AuthorizationService(this); Intent endSessionItent = authService.getEndSessionRequestIntent(endSessionRequest); startActivityForResult(endSessionItent, RC_END_SESSION); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == RC_END_SESSION) { EndSessionResonse resp = EndSessionResonse.fromIntent(data); AuthorizationException ex = AuthorizationException.fromIntent(data); // ... process the response or exception ... } else { // ... } } ``` If instead you wish to directly transition to another activity on completion or cancelation, you can use `performEndSessionRequest`: ```java AuthorizationService authService = new AuthorizationService(this); authService.performEndSessionRequest( endSessionRequest, PendingIntent.getActivity(this, 0, new Intent(this, MyAuthCompleteActivity.class), 0), PendingIntent.getActivity(this, 0, new Intent(this, MyAuthCanceledActivity.class), 0)); ``` End session flow will also work involving browser mechanism that is described in authorization mechanism session. Handling response mechanism with transition to another activity should be as follows: ```java public void onCreate(Bundle b) { EndSessionResponse resp = EndSessionResponse.fromIntent(getIntent()); AuthorizationException ex = AuthorizationException.fromIntent(getIntent()); if (resp != null) { // authorization completed } else { // authorization failed, check ex for more details } // ... } ``` ### AuthState persistence Instances of `AuthState` keep track of the authorization and token requests and responses. This is the only object that you need to persist to retain the authorization state of the session. Typically, one would do this by storing the authorization state in SharedPreferences or some other persistent store private to the app: ```java @NonNull public AuthState readAuthState() { SharedPreferences authPrefs = getSharedPreferences("auth", MODE_PRIVATE); String stateJson = authPrefs.getString("stateJson", null); if (stateJson != null) { return AuthState.jsonDeserialize(stateJson); } else { return new AuthState(); } } public void writeAuthState(@NonNull AuthState state) { SharedPreferences authPrefs = getSharedPreferences("auth", MODE_PRIVATE); authPrefs.edit() .putString("stateJson", state.jsonSerializeString()) .apply(); } ``` The demo app has an [AuthStateManager](https://github.com/openid/AppAuth-Android/blob/master/app/java/net/openid/appauthdemo/AuthStateManager.java) type which demonstrates this in more detail. ## Advanced configuration AppAuth provides some advanced configuration options via [AppAuthConfiguration](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AppAuthConfiguration.java) instances, which can be provided to [AuthorizationService](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationService.java) during construction. ### Controlling which browser is used for authorization Some applications require explicit control over which browsers can be used for authorization - for example, to require that Chrome be used for second factor authentication to work, or require that some custom browser is used for authentication in an enterprise environment. Control over which browsers can be used can be achieved by defining a [BrowserMatcher](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/BrowserMatcher.java), and supplying this to the builder of AppAuthConfiguration. A BrowserMatcher is suppled with a [BrowserDescriptor](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/BrowserDescriptor.java) instance, and must decide whether this browser is permitted for the authorization flow. By default, [AnyBrowserMatcher](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/AnyBrowserMatcher.java) is used. For your convenience, utility classes to help define a browser matcher are provided, such as: - [Browsers](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/Browsers.java): contains a set of constants for the official package names and signatures of Chrome, Firefox and Samsung SBrowser. - [VersionedBrowserMatcher](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/VersionedBrowserMatcher.java): will match a browser if it has a matching package name and signature, and a version number within a defined [VersionRange](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/VersionRange.java). This class also provides some static instances for matching Chrome, Firefox and Samsung SBrowser. - [BrowserAllowList](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/BrowserAllowList.java): takes a list of BrowserMatcher instances, and will match a browser if any of these child BrowserMatcher instances signals a match. - [BrowserDenyList](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/browser/BrowserDenyList.java): the inverse of BrowserAllowList - takes a list of browser matcher instances, and will match a browser if it _does not_ match any of these child BrowserMatcher instances. For instance, in order to restrict the authorization flow to using Chrome or SBrowser as a custom tab: ```java AppAuthConfiguration appAuthConfig = new AppAuthConfiguration.Builder() .setBrowserMatcher(new BrowserAllowList( VersionedBrowserMatcher.CHROME_CUSTOM_TAB, VersionedBrowserMatcher.SAMSUNG_CUSTOM_TAB)) .build(); AuthorizationService authService = new AuthorizationService(context, appAuthConfig); ``` Or, to prevent the use of a buggy version of the custom tabs in Samsung SBrowser: ```java AppAuthConfiguration appAuthConfig = new AppAuthConfiguration.Builder() .setBrowserMatcher(new BrowserDenyList( new VersionedBrowserMatcher( Browsers.SBrowser.PACKAGE_NAME, Browsers.SBrowser.SIGNATURE_SET, true, // when this browser is used via a custom tab VersionRange.atMost("5.3") ))) .build(); AuthorizationService authService = new AuthorizationService(context, appAuthConfig); ``` ### Customizing the connection builder for HTTP requests It can be desirable to customize how HTTP connections are made when performing token requests, for instance to use [certificate pinning](https://www.owasp.org/index.php/Certificate_and_Public_Key_Pinning) or to add additional trusted certificate authorities for an enterprise environment. This can be achieved in AppAuth by providing a custom [ConnectionBuilder](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/connectivity/ConnectionBuilder.java) instance. For example, to custom the SSL socket factory used, one could do the following: ```java AppAuthConfiguration appAuthConfig = new AppAuthConfiguration.Builder() .setConnectionBuilder(new ConnectionBuilder() { public HttpURLConnection openConnect(Uri uri) throws IOException { URL url = new URL(uri.toString()); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); if (connection instanceof HttpsUrlConnection) { HttpsURLConnection connection = (HttpsURLConnection) connection; connection.setSSLSocketFactory(MySocketFactory.getInstance()); } } }) .build(); ``` ### Issues with [ID Token](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/IdToken.java#L118) validation ID Token validation was introduced in `0.8.0` but not all authorization servers or configurations support it correctly. - For testing environments [setSkipIssuerHttpsCheck](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AppAuthConfiguration.java#L129) can be used to bypass the fact the issuer needs to be HTTPS. ```java AppAuthConfiguration appAuthConfig = new AppAuthConfiguration.Builder() .setSkipIssuerHttpsCheck(true) .build() ``` - For services that don't support nonce[s] resulting in **IdTokenException** `Nonce mismatch` just set nonce to `null` on the `AuthorizationRequest`. Please consider **raising an issue** with your Identity Provider and removing this once it is fixed. ```java AuthorizationRequest authRequest = authRequestBuilder .setNonce(null) .build(); ``` ## Dynamic client registration AppAuth supports the [OAuth2 dynamic client registration protocol](https://tools.ietf.org/html/rfc7591). In order to dynamically register a client, create a [RegistrationRequest](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/RegistrationRequest.java) and dispatch it using [performRegistrationRequest](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationService.java#L278) on your AuthorizationService instance. The registration endpoint can either be defined directly as part of your [AuthorizationServiceConfiguration](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/AuthorizationServiceConfiguration.java), or discovered from an OpenID Connect discovery document. ```java RegistrationRequest registrationRequest = new RegistrationRequest.Builder( serviceConfig, Arrays.asList(redirectUri)) .build(); ``` Requests are dispatched with the help of `AuthorizationService`. As this request is asynchronous the response is passed to a callback: ```java service.performRegistrationRequest( registrationRequest, new AuthorizationService.RegistrationResponseCallback() { @Override public void onRegistrationRequestCompleted( @Nullable RegistrationResponse resp, @Nullable AuthorizationException ex) { if (resp != null) { // registration succeeded, store the registration response AuthState state = new AuthState(resp); //proceed to authorization... } else { // registration failed, check ex for more details } } }); ``` ## Utilizing client secrets (DANGEROUS) We _strongly recommend_ you avoid using static client secrets in your native applications whenever possible. Client secrets derived via a dynamic client registration are safe to use, but static client secrets can be easily extracted from your apps and allow others to impersonate your app and steal user data. If client secrets must be used by the OAuth2 provider you are integrating with, we strongly recommend performing the code exchange step on your backend, where the client secret can be kept hidden. Having said this, in some cases using client secrets is unavoidable. In these cases, a [ClientAuthentication](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/ClientAuthentication.java) instance can be provided to AppAuth when performing a token request. This allows additional parameters (both HTTP headers and request body parameters) to be added to token requests. Two standard implementations of ClientAuthentication are provided: - [ClientSecretBasic](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/ClientSecretBasic.java): includes a client ID and client secret as an HTTP Basic Authorization header. - [ClientSecretPost](https://github.com/openid/AppAuth-Android/blob/master/library/java/net/openid/appauth/ClientSecretPost.java): includes a client ID and client secret as additional request parameters. So, in order to send a token request using HTTP basic authorization, one would write: ```java ClientAuthentication clientAuth = new ClientSecretBasic(MY_CLIENT_SECRET); TokenRequest req = ...; authService.performTokenRequest(req, clientAuth, callback); ``` This can also be done when using `performActionWithFreshTokens` on AuthState: ```java ClientAuthentication clientAuth = new ClientSecretPost(MY_CLIENT_SECRET); authState.performActionWithFreshTokens( authService, clientAuth, action); ``` ## Modifying or contributing to AppAuth This project requires the Android SDK for API level 25 (Nougat) to build, though the produced binaries only require API level 16 (Jellybean) to be used. We recommend that you fork and/or clone this repository to make modifications; downloading the source has been known to cause some developers problems. For contributors, see the additional instructions in [CONTRIBUTING.md](https://github.com/openid/AppAuth-Android/blob/master/CONTRIBUTING.md). ### Building from the Command line AppAuth for Android uses Gradle as its build system. In order to build the library and app binaries, run `./gradlew assemble`. The library AAR files are output to `library/build/outputs/aar`, while the demo app is output to `app/build/outputs/apk`. In order to run the tests and code analysis, run `./gradlew check`. ### Building from Android Studio In AndroidStudio, File -> New -> Import project. Select the root folder (the one with the `build.gradle` file).

# Liberty House Club **A Parallel Binance Chain to Enable Smart Contracts** _NOTE: This document is under development. Please check regularly for updates!_ ## Table of Contents - [Motivation](#motivation) - [Design Principles](#design-principles) - [Consensus and Validator Quorum](#consensus-and-validator-quorum) * [Proof of Staked Authority](#proof-of-staked-authority) * [Validator Quorum](#validator-quorum) * [Security and Finality](#security-and-finality) * [Reward](#reward) - [Token Economy](#token-economy) * [Native Token](#native-token) * [Other Tokens](#other-tokens) - [Cross-Chain Transfer and Communication](#cross-chain-transfer-and-communication) * [Cross-Chain Transfer](#cross-chain-transfer) * [BC to BSC Architecture](#bc-to-bsc-architecture) * [BSC to BC Architecture](#bsc-to-bc-architecture) * [Timeout and Error Handling](#timeout-and-error-handling) * [Cross-Chain User Experience](#cross-chain-user-experience) * [Cross-Chain Contract Event](#cross-chain-contract-event) - [Staking and Governance](#staking-and-governance) * [Staking on BC](#staking-on-bc) * [Rewarding](#rewarding) * [Slashing](#slashing) - [Relayers](#relayers) * [BSC Relayers](#bsc-relayers) * [Oracle Relayers](#oracle-relayers) - [Outlook](#outlook) # Motivation After its mainnet community [launch](https://www.binance.com/en/blog/327334696200323072/Binance-DEX-Launches-on-Binance-Chain-Invites-Further-Community-Development) in April 2019, [Binance Chain](https://www.binance.org) has exhibited its high speed and large throughput design. Binance Chain’s primary focus, its native [decentralized application](https://en.wikipedia.org/wiki/Decentralized_application) (“dApp”) [Binance DEX](https://www.binance.org/trade), has demonstrated its low-latency matching with large capacity headroom by handling millions of trading volume in a short time. Flexibility and usability are often in an inverse relationship with performance. The concentration on providing a convenient digital asset issuing and trading venue also brings limitations. Binance Chain's most requested feature is the programmable extendibility, or simply the [Smart Contract](https://en.wikipedia.org/wiki/Smart_contract) and Virtual Machine functions. Digital asset issuers and owners struggle to add new decentralized features for their assets or introduce any sort of community governance and activities. Despite this high demand for adding the Smart Contract feature onto Binance Chain, it is a hard decision to make. The execution of a Smart Contract may slow down the exchange function and add non-deterministic factors to trading. If that compromise could be tolerated, it might be a straightforward idea to introduce a new Virtual Machine specification based on [Tendermint](https://tendermint.com/core/), based on the current underlying consensus protocol and major [RPC](https://docs.binance.org/api-reference/node-rpc.html) implementation of Binance Chain. But all these will increase the learning requirements for all existing dApp communities, and will not be very welcomed. We propose a parallel blockchain of the current Binance Chain to retain the high performance of the native DEX blockchain and to support a friendly Smart Contract function at the same time. # Design Principles After the creation of the parallel blockchain into the Binance Chain ecosystem, two blockchains will run side by side to provide different services. The new parallel chain will be called “**Binance Smart Chain**” (short as “**BSC**” for the below sections), while the existing mainnet remains named “**Binance Chain**” (short as “**BC**” for the below sections). Here are the design principles of **BSC**: 1. **Standalone Blockchain**: technically, BSC is a standalone blockchain, instead of a layer-2 solution. Most BSC fundamental technical and business functions should be self-contained so that it can run well even if the BC stopped for a short period. 2. **Ethereum Compatibility**: The first practical and widely-used Smart Contract platform is Ethereum. To take advantage of the relatively mature applications and community, BSC chooses to be compatible with the existing Ethereum mainnet. This means most of the **dApps**, ecosystem components, and toolings will work with BSC and require zero or minimum changes; BSC node will require similar (or a bit higher) hardware specification and skills to run and operate. The implementation should leave room for BSC to catch up with further Ethereum upgrades. 3. **Staking Involved Consensus and Governance**: Staking-based consensus is more environmentally friendly and leaves more flexible option to the community governance. Expectedly, this consensus should enable better network performance over [proof-of-work](https://en.wikipedia.org/wiki/Proof_of_work) blockchain system, i.e., faster blocking time and higher transaction capacity. 4. **Native Cross-Chain Communication**: both BC and BSC will be implemented with native support for cross-chain communication among the two blockchains. The communication protocol should be bi-directional, decentralized, and trustless. It will concentrate on moving digital assets between BC and BSC, i.e., [BEP2](https://github.com/binance-chain/BEPs/blob/master/BEP2.md) tokens, and eventually, other BEP tokens introduced later. The protocol should care for the minimum of other items stored in the state of the blockchains, with only a few exceptions. # Consensus and Validator Quorum Based on the above design principles, the consensus protocol of BSC is to fulfill the following goals: 1. Blocking time should be shorter than Ethereum network, e.g. 5 seconds or even shorter. 2. It requires limited time to confirm the finality of transactions, e.g. around 1-min level or shorter. 3. There is no inflation of native token: BNB, the block reward is collected from transaction fees, and it will be paid in BNB. 4. It is compatible with Ethereum system as much as possible. 5. It allows modern [proof-of-stake](https://en.wikipedia.org/wiki/Proof_of_stake) blockchain network governance. ## Proof of Staked Authority Although Proof-of-Work (PoW) has been recognized as a practical mechanism to implement a decentralized network, it is not friendly to the environment and also requires a large size of participants to maintain the security. Ethereum and some other blockchain networks, such as [MATIC Bor](https://github.com/maticnetwork/bor), [TOMOChain](https://tomochain.com/), [GoChain](https://gochain.io/), [xDAI](https://xdai.io/), do use [Proof-of-Authority(PoA)](https://en.wikipedia.org/wiki/Proof_of_authority) or its variants in different scenarios, including both testnet and mainnet. PoA provides some defense to 51% attack, with improved efficiency and tolerance to certain levels of Byzantine players (malicious or hacked). It serves as an easy choice to pick as the fundamentals. Meanwhile, the PoA protocol is most criticized for being not as decentralized as PoW, as the validators, i.e. the nodes that take turns to produce blocks, have all the authorities and are prone to corruption and security attacks. Other blockchains, such as EOS and Lisk both, introduce different types of [Delegated Proof of Stake (DPoS)](https://en.bitcoinwiki.org/wiki/DPoS) to allow the token holders to vote and elect the validator set. It increases the decentralization and favors community governance. BSC here proposes to combine DPoS and PoA for consensus, so that: 1. Blocks are produced by a limited set of validators 2. Validators take turns to produce blocks in a PoA manner, similar to [Ethereum’s Clique](https://eips.ethereum.org/EIPS/eip-225) consensus design 3. Validator set are elected in and out based on a staking based governance ## Validator Quorum In the genesis stage, a few trusted nodes will run as the initial Validator Set. After the blocking starts, anyone can compete to join as candidates to elect as a validator. The staking status decides the top 21 most staked nodes to be the next validator set, and such an election will repeat every 24 hours. **BNB** is the token used to stake for BSC. In order to remain as compatible as Ethereum and upgradeable to future consensus protocols to be developed, BSC chooses to rely on the **BC** for staking management (Please refer to the below “[Staking and Governance](#staking-and-governance)” section). There is a **dedicated staking module for BSC on BC**. It will accept BSC staking from BNB holders and calculate the highest staked node set. Upon every UTC midnight, BC will issue a verifiable `ValidatorSetUpdate` cross-chain message to notify BSC to update its validator set. While producing further blocks, the existing BSC validators check whether there is a `ValidatorSetUpdate` message relayed onto BSC periodically. If there is, they will update the validator set after an **epoch period**, i.e. a predefined number of blocking time. For example, if BSC produces a block every 5 seconds, and the epoch period is 240 blocks, then the current validator set will check and update the validator set for the next epoch in 1200 seconds (20 minutes). ## Security and Finality Given there are more than ½\*N+1 validators are honest, PoA based networks usually work securely and properly. However, there are still cases where certain amount Byzantine validators may still manage to attack the network, e.g. through the “[Clone Attack](https://arxiv.org/pdf/1902.10244.pdf)”. To secure as much as BC, BSC users are encouraged to wait until receiving blocks sealed by more than ⅔\*N+1 different validators. In that way, the BSC can be trusted at a similar security level to BC and can tolerate less than ⅓\*N Byzantine validators. With 21 validators, if the block time is 5 seconds, the ⅔\*N+1 different validator seals will need a time period of (⅔\*21+1)*5 = 75 seconds. Any critical applications for BSC may have to wait for ⅔\*N+1 to ensure a relatively secure finality. However, besides such arrangement, BSC does introduce **Slashing** logic to penalize Byzantine validators for **double signing** or **inavailability**, which will be covered in the “Staking and Governance” section later. This Slashing logic will expose the malicious validators in a very short time and make the “Clone Attack” very hard or extremely non-beneficial to execute. With this enhancement, ½\*N+1 or even fewer blocks are enough as confirmation for most transactions. ## Reward All the BSC validators in the current validator set will be rewarded with transaction **fees in BNB**. As BNB is not an inflationary token, there will be no mining rewards as what Bitcoin and Ethereum network generate, and the gas fee is the major reward for validators. As BNB is also utility tokens with other use cases, delegators and validators will still enjoy other benefits of holding BNB. The reward for validators is the fees collected from transactions in each block. Validators can decide how much to give back to the delegators who stake their BNB to them, in order to attract more staking. Every validator will take turns to produce the blocks in the same probability (if they stick to 100% liveness), thus, in the long run, all the stable validators may get a similar size of the reward. Meanwhile, the stakes on each validator may be different, so this brings a counter-intuitive situation that more users trust and delegate to one validator, they potentially get less reward. So rational delegators will tend to delegate to the one with fewer stakes as long as the validator is still trustful (insecure validator may bring slashable risk). In the end, the stakes on all the validators will have less variation. This will actually prevent the stake concentration and “winner wins forever” problem seen on some other networks. Some parts of the gas fee will also be rewarded to relayers for Cross-Chain communication. Please refer to the “[Relayers](#relayers)” section below. # Token Economy BC and BSC share the same token universe for BNB and BEP2 tokens. This defines: 1. The same token can circulate on both networks, and flow between them bi-directionally via a cross-chain communication mechanism. 2. The total circulation of the same token should be managed across the two networks, i.e. the total effective supply of a token should be the sum of the token’s total effective supply on both BSC and BC. 3. The tokens can be initially created on BSC in a similar format as ERC20 token standard, or on BC as a BEP2, then created on the other. There are native ways on both networks to link the two and secure the total supply of the token. ## Native Token BNB will run on BSC in the same way as ETH runs on Ethereum so that it remains as “native token” for both BSC and BC. This means, in addition to BNB is used to pay most of the fees on Binance Chain and Binance DEX, BNB will be also used to: 1. pay “fees“ to deploy smart contracts on BSC 2. stake on selected BSC validators, and get corresponding rewards 3. perform cross-chain operations, such as transfer token assets across BC and BSC ### Seed Fund Certain amounts of BNB will be burnt on BC and minted on BSC during its genesis stage. This amount is called “Seed Fund” to circulate on BSC after the first block, which will be dispatched to the initial BC-to-BSC Relayer(described in later sections) and initial validator set introduced at genesis. These BNBs are used to pay transaction fees in the early stage to transfer more BNB from BC onto BSC via the cross-chain mechanism. The BNB cross-chain transfer is discussed in a later section, but for BC to BSC transfer, it is generally to lock BNB on BC from the source address of the transfer to a system-controlled address and unlock the corresponding amount from special contract to the target address of the transfer on BSC, or reversely, when transferring from BSC to BC, it is to lock BNB from the source address on BSC into a special contract and release locked amount on BC from the system address to the target address. The logic is related to native code on BC and a series of smart contracts on BSC. ## Other Tokens BC supports BEP2 tokens and upcoming [BEP8 tokens](https://github.com/binance-chain/BEPs/pull/69), which are native assets transferrable and tradable (if listed) via fast transactions and sub-second finality. Meanwhile, as BSC is Ethereum compatible, it is natural to support ERC20 tokens on BSC, which here is called “**BEP2E**” (with the real name to be introduced by the future BEPs,it potentially covers BEP8 as well). BEP2E may be “Enhanced” by adding a few more methods to expose more information, such as token denomination, decimal precision definition and the owner address who can decide the Token Binding across the chains. BSC and BC work together to ensure that one token can circulate in both formats with confirmed total supply and be used in different use cases. ### Token Binding BEP2 tokens will be extended to host a new attribute to associate the token with a BSC BEP2E token contract, called “**Binder**”, and this process of association is called “**Token Binding**”. Token Binding can happen at any time after BEP2 and BEP2E are ready. The token owners of either BEP2 or BEP2E don’t need to bother about the Binding, until before they really want to use the tokens on different scenarios. Issuers can either create BEP2 first or BEP2E first, and they can be bound at a later time. Of course, it is encouraged for all the issuers of BEP2 and BEP2E to set the Binding up early after the issuance. A typical procedure to bind the BEP2 and BEP2E will be like the below: 1. Ensure both the BEP2 token and the BEP2E token both exist on each blockchain, with the same total supply. BEP2E should have 3 more methods than typical ERC20 token standard: * symbol(): get token symbol * decimals(): get the number of the token decimal digits * owner(): get **BEP2E contract owner’s address.** This value should be initialized in the BEP2E contract constructor so that the further binding action can verify whether the action is from the BEP2E owner. 2. Decide the initial circulation on both blockchains. Suppose the total supply is *S*, and the expected initial circulating supply on BC is *K*, then the owner should lock S-K tokens to a system controlled address on BC. 3. Equivalently, *K* tokens is locked in the special contract on BSC, which handles major binding functions and is named as **TokenHub**. The issuer of the BEP2E token should lock the *K* amount of that token into TokenHub, resulting in *S-K* tokens to circulate on BSC. Thus the total circulation across 2 blockchains remains as *S*. 4. The issuer of BEP2 token sends the bind transaction on BC. Once the transaction is executed successfully after proper verification: * It transfers *S-K* tokens to a system-controlled address on BC. * A cross-chain bind request package will be created, waiting for Relayers to relay. 5. BSC Relayers will relay the cross-chain bind request package into **TokenHub** on BSC, and the corresponding request and information will be stored into the contract. 6. The contract owner and only the owner can run a special method of TokenHub contract, `ApproveBind`, to verify the binding request to mark it as a success. It will confirm: * the token has not been bound; * the binding is for the proper symbol, with proper total supply and decimal information; * the proper lock are done on both networks; 10. Once the `ApproveBind` method has succeeded, TokenHub will mark the two tokens are bounded and share the same circulation on BSC, and the status will be propagated back to BC. After this final confirmation, the BEP2E contract address and decimals will be written onto the BEP2 token as a new attribute on BC, and the tokens can be transferred across the two blockchains bidirectionally. If the ApproveBind fails, the failure event will also be propagated back to BC to release the locked tokens, and the above steps can be re-tried later. # Cross-Chain Transfer and Communication Cross-chain communication is the key foundation to allow the community to take advantage of the dual chain structure: * users are free to create any tokenization, financial products, and digital assets on BSC or BC as they wish * the items on BSC can be manually and programmingly traded and circulated in a stable, high throughput, lighting fast and friendly environment of BC * users can operate these in one UI and tooling ecosystem. ## Cross-Chain Transfer The cross-chain transfer is the key communication between the two blockchains. Essentially the logic is: 1. the `transfer-out` blockchain will lock the amount from source owner addresses into a system controlled address/contracts; 2. the `transfer-in` blockchain will unlock the amount from the system controlled address/contracts and send it to target addresses. The cross-chain transfer package message should allow the BSC Relayers and BC **Oracle Relayers** to verify: 1. Enough amount of token assets are removed from the source address and locked into a system controlled addresses/contracts on the source blockchain. And this can be confirmed on the target blockchain. 2. Proper amounts of token assets are released from a system controlled addresses/contracts and allocated into target addresses on the target blockchain. If this fails, it can be confirmed on source blockchain, so that the locked token can be released back (may deduct fees). 3. The sum of the total circulation of the token assets across the 2 blockchains are not changed after this transfer action completes, no matter if the transfer succeeds or not.  The architecture of cross-chain communication is as in the above diagram. To accommodate the 2 heteroid systems, communication handling is different in each direction. ## BC to BSC Architecture BC is a Tendermint-based, instant finality blockchain. Validators with at least ⅔\*N+1 of the total voting power will co-sign each block on the chain. So that it is practical to verify the block transactions and even the state value via **Block Header** and **Merkle Proof** verification. This has been researched and implemented as “**Light-Client Protocol**”, which are intensively discussed in [the Ethereum](https://github.com/ethereum/wiki/wiki/Light-client-protocol) community, studied and implemented for [Cosmos inter-chain communication](https://github.com/cosmos/ics/blob/a4173c91560567bdb7cc9abee8e61256fc3725e9/spec/ics-007-tendermint-client/README.md). BC-to-BSC communication will be verified in an “**on-chain light client**” implemented via BSC **Smart Contracts** (some of them may be **“pre-compiled”**). After some transactions and state change happen on BC, if a transaction is defined to trigger cross-chain communication,the Cross-chain “**package**” message will be created and **BSC Relayers** will pass and submit them onto BSC as data into the "build-in system contracts". The build-in system contracts will verify the package and execute the transactions if it passes the verification. The verification will be guaranteed with the below design: 1. BC blocking status will be synced to the light client contracts on BSC from time to time, via block header and pre-commits, for the below information: * block and app hash of BC that are signed by validators * current validatorset, and validator set update 2. the key-value from the blockchain state will be verified based on the Merkle Proof and information from above #1. After confirming the key-value is accurate and trustful, the build-in system contracts will execute the actions corresponding to the cross-chain packages. Some examples of such packages that can be created for BC-to-BSC are: 1. Bind: bind the BEP2 tokens and BEP2E 2. Transfer: transfer tokens after binding, this means the circulation will decrease (be locked) from BC and appear in the target address balance on BSC 3. Error Handling: to handle any timeout/failure event for BSC-to-BC communication 4. Validatorset update of BSC To ensure no duplication, proper message sequence and timely timeout, there is a “Channel” concept introduced on BC to manage any types of the communication. For relayers, please also refer to the below “Relayers” section. ## BSC to BC Architecture BSC uses Proof of Staked Authority consensus protocol, which has a chance to fork and requires confirmation of more blocks. One block only has the signature of one validator, so that it is not easy to rely on one block to verify data from BSC. To take full advantage of validator quorum of BC, an idea similar to many [Bridge ](https://github.com/poanetwork/poa-bridge)or Oracle blockchains is adopted: 1. The cross-chain communication requests from BSC will be submitted and executed onto BSC as transactions. The execution of the transanction wil emit `Events`, and such events can be observed and packaged in certain “**Oracle**” onto BC. Instead of Block Headers, Hash and Merkle Proof, this type of “Oracle” package directly contains the cross-chain information for actions, such as sender, receiver and amount for transfer. 2. To ensure the security of the Oracle, the validators of BC will form anothe quorum of “**Oracle Relayers**”. Each validator of the BC should run a **dedicated process** as the Oracle Relayer. These Oracle Relayers will submit and vote for the cross-chain communication package, like Oracle, onto BC, using the same validator keys. Any package signed by more than ⅔\*N+1 Oracle Relayers’ voting power is as secure as any block signed by ⅔\*N+1 of the same quorum of validators’ voting power. By using the same validator quorum, it saves the light client code on BC and continuous block updates onto BC. Such Oracles also have Oracle IDs and types, to ensure sequencing and proper error handling. ## Timeout and Error Handling There are scenarios that the cross-chain communication fails. For example, the relayed package cannot be executed on BSC due to some coding bug in the contracts. **Timeout and error handling logics are** used in such scenarios. For the recognizable user and system errors or any expected exceptions, the two networks should heal themselves. For example, when BC to BSC transfer fails, BSC will issue a failure event and Oracle Relayers will execute a refund on BC; when BSC to BC transfer fails, BC will issue a refund package for Relayer to relay in order to unlock the fund. However, unexpected error or exception may still happen on any step of the cross-chain communication. In such a case, the Relayers and Oracle Relayers will discover that the corresponding cross-chain channel is stuck in a particular sequence. After a Timeout period, the Relayers and Oracle Relayers can request a “SkipSequence” transaction, the stuck sequence will be marked as “Unexecutable”. A corresponding alerts will be raised, and the community has to discuss how to handle this scenario, e.g. payback via the sponsor of the validators, or event clear the fund during next network upgrade. ## Cross-Chain User Experience Ideally, users expect to use two parallel chains in the same way as they use one single chain. It requires more aggregated transaction types to be added onto the cross-chain communication to enable this, which will add great complexity, tight coupling, and maintenance burden. Here BC and BSC only implement the basic operations to enable the value flow in the initial launch and leave most of the user experience work to client side UI, such as wallets. E.g. a great wallet may allow users to sell a token directly from BSC onto BC’s DEX order book, in a secure way. ## Cross-Chain Contract Event Cross-Chain Contract Event (CCCE) is designed to allow a smart contract to trigger cross-chain transactions, directly through the contract code. This becomes possible based on: 1. Standard system contracts can be provided to serve operations callable by general smart contracts; 2. Standard events can be emitted by the standard contracts; 3. Oracle Relayers can capture the standard events, and trigger the corresponding cross-chain operations; 4. Dedicated, code-managed address (account) can be created on BC and accessed by the contracts on the BSC, here it is named as **“Contract Address on BC” (CAoB)**. Several standard operations are implemented: 1. BSC to BC transfer: this is implemented in the same way as normal BSC to BC transfer, by only triggered via standard contract. The fund can be transferred to any addresses on BC, including the corresponding CAoB of the transfer originating contract. 2. Transfer on BC: this is implemented as a special cross-chain transfer, while the real transfer is from **CAoB** to any other address (even another CAoB). 3. BC to BSC transfer: this is implemented as two-pass cross-chain communication. The first is triggered by the BSC contract and propagated onto BC, and then in the second pass, BC will start a normal BC to BSC cross-chain transfer, from **CAoB** to contract address on BSC. A special note should be paid on that the BSC contract only increases balance upon any transfer coming in on the second pass, and the error handling in the second pass is the same as the normal BC to BSC transfer. 4. IOC (Immediate-Or-Cancel) Trade Out: the primary goal of transferring assets to BC is to trade. This event will instruct to trade a certain amount of an asset in CAoB into another asset as much as possible and transfer out all the results, i.e. the left the source and the traded target tokens of the trade, back to BSC. BC will handle such relayed events by sending an “Immediate-Or-Cancel”, i.e. IOC order onto the trading pairs, once the next matching finishes, the result will be relayed back to BSC, which can be in either one or two assets. 5. Auction Trade Out: Such event will instruct BC to send an auction order to trade a certain amount of an asset in **CAoB** into another asset as much as possible and transfer out all the results back to BSC at the end of the auction. Auction function is upcoming on BC. There are some details for the Trade Out: 1. both can have a limit price (absolute or relative) for the trade; 2. the end result will be written as cross-chain packages to relay back to BSC; 3. cross-chain communication fees may be charged from the asset transferred back to BSC; 4. BSC contract maintains a mirror of the balance and outstanding orders on CAoB. No matter what error happens during the Trade Out, the final status will be propagated back to the originating contract and clear its internal state. With the above features, it simply adds the cross-chain transfer and exchange functions with high liquidity onto all the smart contracts on BSC. It will greatly add the application scenarios on Smart Contract and dApps, and make 1 chain +1 chain > 2 chains. # Staking and Governance Proof of Staked Authority brings in decentralization and community involvement. Its core logic can be summarized as the below. You may see similar ideas from other networks, especially Cosmos and EOS. 1. Token holders, including the validators, can put their tokens “**bonded**” into the stake. Token holders can **delegate** their tokens onto any validator or validator candidate, to expect it can become an actual validator, and later they can choose a different validator or candidate to **re-delegate** their tokens¹. 2. All validator candidates will be ranked by the number of bonded tokens on them, and the top ones will become the real validators. 3. Validators can share (part of) their blocking reward with their delegators. 4. Validators can suffer from “**Slashing**”, a punishment for their bad behaviors, such as double sign and/or instability. 5. There is an “**unbonding period**” for validators and delegators so that the system makes sure the tokens remain bonded when bad behaviors are caught, the responsible will get slashed during this period. ## Staking on BC Ideally, such staking and reward logic should be built into the blockchain, and automatically executed as the blocking happens. Cosmos Hub, who shares the same Tendermint consensus and libraries with Binance Chain, works in this way. BC has been preparing to enable staking logic since the design days. On the other side, as BSC wants to remain compatible with Ethereum as much as possible, it is a great challenge and efforts to implement such logic on it. This is especially true when Ethereum itself may move into a different Proof of Stake consensus protocol in a short (or longer) time. In order to keep the compatibility and reuse the good foundation of BC, the staking logic of BSC is implemented on BC: 1. The staking token is BNB, as it is a native token on both blockchains anyway 2. The staking, i.e. token bond and delegation actions and records for BSC, happens on BC. 3. The BSC validator set is determined by its staking and delegation logic, via a staking module built on BC for BSC, and propagated every day UTC 00:00 from BC to BSC via Cross-Chain communication. 4. The reward distribution happens on BC around every day UTC 00:00. ## Rewarding Both the validator update and reward distribution happen every day around UTC 00:00. This is to save the cost of frequent staking updates and block reward distribution. This cost can be significant, as the blocking reward is collected on BSC and distributed on BC to BSC validators and delegators. (Please note BC blocking fees will remain rewarding to BC validators only.) A deliberate delay is introduced here to make sure the distribution is fair: 1. The blocking reward will not be sent to validator right away, instead, they will be distributed and accumulated on a contract; 2. Upon receiving the validator set update into BSC, it will trigger a few cross-chain transfers to transfer the reward to custody addresses on the corresponding validators. The custody addresses are owned by the system so that the reward cannot be spent until the promised distribution to delegators happens. 3. In order to make the synchronization simpler and allocate time to accommodate slashing, the reward for N day will be only distributed in N+2 days. After the delegators get the reward, the left will be transferred to validators’ own reward addresses. ## Slashing Slashing is part of the on-chain governance, to ensure the malicious or negative behaviors are punished. BSC slash can be submitted by anyone. The transaction submission requires **slash evidence** and cost fees but also brings a larger reward when it is successful. So far there are two slashable cases. ### Double Sign It is quite a serious error and very likely deliberate offense when a validator signs more than one block with the same height and parent block. The reference protocol implementation should already have logic to prevent this, so only the malicious code can trigger this. When Double Sign happens, the validator should be removed from the Validator **Set** right away. Anyone can submit a slash request on BC with the evidence of Double Sign of BSC, which should contain the 2 block headers with the same height and parent block, sealed by the offending validator. Upon receiving the evidence, if the BC verifies it to be valid: 1. The validator will be removed from validator set by an instance BSC validator set update Cross-Chain update; 2. A predefined amount of BNB would be slashed from the **self-delegated** BNB of the validator; Both validator and its delegators will not receive the staking rewards. 3. Part of the slashed BNB will allocate to the submitter’s address, which is a reward and larger than the cost of submitting slash request transaction 4. The rest of the slashed BNB will allocate to the other validators’ custody addresses, and distributed to all delegators in the same way as blocking reward. ### Inavailability The liveness of BSC relies on everyone in the Proof of Staked Authority validator set can produce blocks timely when it is their turn. Validators can miss their turn due to any reason, especially problems in their hardware, software, configuration or network. This instability of the operation will hurt the performance and introduce more indeterministic into the system. There can be an internal smart contract responsible for recording the missed blocking metrics of each validator. Once the metrics are above the predefined threshold, the blocking reward for validator will not be relayed to BC for distribution but shared with other better validators. In such a way, the poorly-operating validator should be gradually voted out of the validator set as their delegators will receive less or none reward. If the metrics remain above another higher level of threshold, the validator will be dropped from the rotation, and this will be propagated back to BC, then a predefined amount of BNB would be slashed from the **self-delegated** BNB of the validator. Both validators and delegators will not receive their staking rewards. ### Governance Parameters There are many system parameters to control the behavior of the BSC, e.g. slash amount, cross-chain transfer fees. All these parameters will be determined by BSC Validator Set together through a proposal-vote process based on their staking. Such the process will be carried on BC, and the new parameter values will be picked up by corresponding system contracts via a cross-chain communication. # Relayers Relayers are responsible to submit Cross-Chain Communication Packages between the two blockchains. Due to the heterogeneous parallel chain structure, two different types of Relayers are created. ## BSC Relayers Relayers for BC to BSC communication referred to as “**BSC Relayers**”, or just simply “Relayers”. Relayer is a standalone process that can be run by anyone, and anywhere, except that Relayers must register themselves onto BSC and deposit a certain refundable amount of BNB. Only relaying requests from the registered Relayers will be accepted by BSC. The package they relay will be verified by the on-chain light client on BSC. The successful relay needs to pass enough verification and costs gas fees on BSC, and thus there should be incentive reward to encourage the community to run Relayers. ### Incentives There are two major communication types: 1. Users triggered Operations, such as `token bind` or `cross chain transfer`. Users must pay additional fee to as relayer reward. The reward will be shared with the relayers who sync the referenced blockchain headers. Besides, the reward won't be paid the relayers' accounts directly. A reward distribution mechanism will be brought in to avoid monopolization. 2. System Synchronization, such as delivering `refund package`(caused by failures of most oracle relayers), special blockchain header synchronization(header contains BC validatorset update), BSC staking package. System reward contract will pay reward to relayers' accounts directly. If some Relayers have faster networks and better hardware, they can monopolize all the package relaying and leave no reward to others. Thus fewer participants will join for relaying, which encourages centralization and harms the efficiency and security of the network. Ideally, due to the decentralization and dynamic re-election of BSC validators, one Relayer can hardly be always the first to relay every message. But in order to avoid the monopolization further, the rewarding economy is also specially designed to minimize such chance: 1. The reward for Relayers will be only distributed in batches, and one batch will cover a number of successful relayed packages. 2. The reward a Relayer can get from a batch distribution is not linearly in proportion to their number of successful relayed packages. Instead, except the first a few relays, the more a Relayer relays during a batch period, the less reward it will collect. ## Oracle Relayers Relayers for BSC to BC communication are using the “Oracle” model, and so-called “**Oracle Relayers**”. Each of the validators must, and only the ones of the validator set, run Oracle Relayers. Each Oracle Relayer watches the blockchain state change. Once it catches Cross-Chain Communication Packages, it will submit to vote for the requests. After Oracle Relayers from ⅔ of the voting power of BC validators vote for the changes, the cross-chain actions will be performed. Oracle Replayers should wait for enough blocks to confirm the finality on BSC before submitting and voting for the cross-chain communication packages onto BC. The cross-chain fees will be distributed to BC validators together with the normal BC blocking rewards. Such oracle type relaying depends on all the validators to support. As all the votes for the cross-chain communication packages are recorded on the blockchain, it is not hard to have a metric system to assess the performance of the Oracle Relayers. The poorest performer may have their rewards clawed back via another Slashing logic introduced in the future. # Outlook It is hard to conclude for Binance Chain, as it has never stopped evolving. The dual-chain strategy is to open the gate for users to take advantage of the fast transferring and trading on one side, and flexible and extendable programming on the other side, but it will be one stop along the development of Binance Chain. Here below are the topics to look into so as to facilitate the community better for more usability and extensibility: 1. Add different digital asset model for different business use cases 2. Enable more data feed, especially DEX market data, to be communicated from Binance DEX to BSC 3. Provide interface and compatibility to integrate with Ethereum, including its further upgrade, and other blockchain 4. Improve client side experience to manage wallets and use blockchain more conveniently ------ [1]: BNB business practitioners may provide other benefits for BNB delegators, as they do now for long term BNB holders.

Catch spec drift before it catches you. Indexes your specs, docs, and decision records, then detects overlap, contradictions, stale docs, and code that drifts from what was decided.

Document-driven development for AI coding assistants. Spec and plan first, then code—no docs, no code.

Setting Up an Angular 2 Environment Using Typescript, Npm and Webpack PreviousNext This Angular 2 tutorial serves for anyone looking to get up and running with Angular 2 and TypeScript fast. Angular 2 Beta Udemy Last week I’ve read the great Angular 2 book from Ninja Squad. Therefore, I figured it was time to put pen to paper and start building Angular 2 applications using TypeScript. That’s why in this tutorial, we’ll learn how to start an Angular 2 project from scratch and go further by building a development environment with Webpack and more. Getting Started 1. Developing and Building a TypeScript App Let’s start by building our first Angular 2 application using Typescript. First, make sure you have Node.js and npm installed. You can refer to the official website for more information about the installation procedure. Then, install Typescript globally via npm by running the following command in your terminal : 1 2 3 npm install -g typescript Once it is installed, we’ll setup our Typescript project by creating a tsconfig.json file in which we specify the compilation options to use for compiling our project. The typescript NPM module we just installed comes with a compiler, named tsc, that we are going to use for initializing a fresh Typescript project : 1 2 3 4 5 6 7 # Create a new project folder and go inside it mkdir angular2-starter && cd angular2-starter # Generate the Typescript configurations file tsc --init --target es5 --sourceMap --experimentalDecorators --emitDecoratorMetadata Running tsc --init create the tsconfig.json in our project directory, which looks like this : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 { "compilerOptions": { "target": "es5", "sourceMap": true, "experimentalDecorators": true, "emitDecoratorMetadata": true, "module": "commonjs", "noImplicitAny": false, "outDir": "built" }, "exclude": [ "node_modules" ] } Along with the --init parameter, we passed the following options to the compiler : --target es5 : specify that we want our code to transpile to ECMASCRIPT 5. Thus, it could be run in every browser. --sourceMap : generate source maps files. It helps when debugging ES5 code with the original Typescript code in the chrome devtools. --experimentalDecorators and --emitDecoratorMetadata : allow to use Typescript with decorators. Also notice that options such as module, outDir or rootDir have been added by default. Feel free to read the documentation for more compiler options. So hit npm init in your terminal, and fill in some answers (you can accept the default for all the prompts). Then, install angular2 by running the following command : 1 2 3 npm install --save angular2 You should now have a package.json file that looks like the following: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 { "name": "angular-starter", "version": "1.0.0", "description": "An Angular 2 Starter kit featuring Angular 2, TypeScript, and Webpack by EloquentWebApp", "main": "index.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "author": "Grégory D'Angelo", "license": "ISC", "dependencies": { "angular2": "^2.0.0-beta.17", "es6-shim": "^0.35.1", "reflect-metadata": "^0.1.2", "rxjs": "^5.0.0-beta.6", "zone.js": "^0.6.17" } } As you can see, angular2 comes with the following dependencies : reflect-metadata : used to enable dependency injection through decorators es6-shim and es6-promise : librairies for ES6 compatabilities and support for ES6 Promise rxjs : a set of librairies for reactive programming zone.js : used to implement zones for Javascript, inspired from Dart. Angular 2 uses it to efficiently detect changes The fundamentals settings are now in place. Let’s create our first Angular 2 application. 2. Creating our First Component The first step is to create a Typescript file at the root folder, and name it app.component.ts. Our application itself will be a component. To do so, we’ll use the @Component decorator by importing it from ‘angular2/core‘. That’s all we need to create our Angular 2 component. 1 2 3 4 5 6 import { Component } from 'angular2/core'; @Component() export class AppComponent { } By prefixing the class by this decorator, it tells Angular that this class is an Angular component. In Angular 2, components are a fundamental concept. It is the way we define views and control the logic on the page. Here’s how to do it : 1 2 3 4 5 6 7 8 9 import { Component } from 'angular2/core'; @Component({ selector: 'app', template: '<h1>Hello, Angular2</h1>' }) export class AppComponent { } We passed in a configuration object to the component decorator. This object has two properties : selector and template. The selector is the HTML element that Angular will looking for. Every times it founds one, Angular will instantiate a new instance of our AppComponent class, and place our template. As you may also notice we export our class at the end. This is our first class so we’ll keep it empty for simplicity. 3. Bootstrapping the App Finally, we need to launch our application. For this, we only need two things : the Angular’s browser bootstrap method, and the application root component that we just wrote. To separate the concerns, create a new file, bootstrap.ts, and import the dependencies : 1 2 3 4 5 6 7 8 9 ///<reference path="node_modules/angular2/typings/browser.d.ts" /> import { bootstrap } from 'angular2/platform/browser'; import { AppComponent } from './app.component'; bootstrap(AppComponent) .catch(err => console.log(err)); As you can see, we call the bootstrap method, passing in our component, AppComponent. Moreover, as stated in the CHANGELOG since 2.0.0-beta.6 (2016-02-11) we may need to add the <reference ... /> line at the top of our bootstrap.ts file when using --target=es5. Feel free to check the CHANGELOG for more details. Last but not least, we need to create an index.html file to host our Angular application. Start by pasting the following lines : 1 2 3 4 5 6 7 8 9 10 11 12 <!DOCTYPE html> <html> <head></head> <body> <app>Loading...</app> </body> </html> For now, it’s a very basic HTML file in which we’ve put the selector <app> that corresponds to our application root component. But we need to add 2 more things in order to launch our application. Indeed, we need to rely on a tool to load application and library modules. For now, we’ll use SystemJS as the module loader. We’ll see later in this tutorial how to install and configure Webpack for our Angular 2 project. And finally, we need to include script dependencies in our HTML file. Let’s do it together step by step. First, start by installing SystemJS : 1 2 3 npm install --save systemjs Then, load it statically in the index.html just after angular2-polyfills. angular2-polyfills is essentially a mashup of zone.js and reflect-metadata. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 <!DOCTYPE html> <html> <head> <script src="node_modules/angular2/bundles/angular2-polyfills.js"></script> <script src="node_modules/systemjs/dist/system.js"></script> </head> <body> <app>Loading...</app> </body> </html> Finally, we need to tell SystemJS where is our bootstrap module and where to find the dependencies used in our application (angular2 and rxjs) : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 <!DOCTYPE html> <html> <head> <script src="node_modules/angular2/bundles/angular2-polyfills.js"></script> <script src="node_modules/systemjs/dist/system.js"></script> <script> System.config({ // we want to import modules without writing .js at the end defaultJSExtensions: true, // the app will need the following dependencies map: { 'angular2': 'node_modules/angular2', 'rxjs': 'node_modules/rxjs' } }); // and to finish, let's boot the app! System.import('built/bootstrap'); </script> </head> <body> <app>Loading...</app> </body> </html> OK! We’re done with the settings and we can now compile and run our application. In order to handle common tasks, include the following npm scripts in the package.json file : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 { "name": "angular-starter", "version": "1.0.0", "description": "An Angular 2 Starter kit featuring Angular 2, TypeScript, and Webpack by EloquentWebApp", "main": "index.js", "scripts": { "start": "concurrently \"npm run watch\" \"npm run serve\"", "watch": "tsc -w", "serve": "lite-server" }, "author": "Grégory D'Angelo", "license": "ISC", "dependencies": { "angular2": "^2.0.0-beta.11", "es6-promise": "^3.1.2", "es6-shim": "^0.35.0", "reflect-metadata": "^0.1.2", "rxjs": "^5.0.0-beta.2", "systemjs": "^0.19.24", "zone.js": "^0.6.5" }, "devDependencies": { "concurrently": "^2.2.0", "lite-server": "^2.2.2" } } The watch script runs the TypeScript compiler in watch mode. It watches TypeScript files and triggers recompilation on changes. The serve script runs an HTTP server to serve our application, and refresh the browser on changes. I’ve used lite-server for that purpose. Install it via npm : 1 2 3 npm install --save-dev lite-server And, the start run the previous 2 scripts concurrently using the concurrently npm package : 1 2 3 npm install --save-dev concurrently So, run npm start and open your browser to http://localhost:3000. You should now briefly see “Loading…”, and then “Hello, Angular2” should appear. Congratulations! We’ve have just finished the first part of this tutorial. Keep going to see how to set a build system using Webpack for working with TypeScript. Creating a useful project structure and toolchain 1. Project Structure As far, we’ve built a basic Angular 2 application with the minimum required dependencies and tools. In this section, we’ll refactor our project structure to ease the development of more complex Angular 2 applications. By the end of this section, you will be able to build your own starter kit to get up and running with Angular 2 and TypeScript fast. More importantly, you will understand how to structure your project and what each tool is responsible for. Sounds great, isn’t it? Let’s do it! The first step is to revamp the file structure of our project. Here’s how it will look : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 angular2-starter/ ├──src/ | ├──bootstrap.ts | ├──index.html | ├──polyfills.ts │ │ │ ├──app/ │ │ ├──app.component.ts │ │ └──app.html │ │ │ └──assets/ │ └──css/ │ └──styles.css │ ├──tsconfig.json ├──typings.json ├──package.json │ └──webpack.config.js There are some new files, but don’t worry we will dive into each one of them through this section. What’s important for now, it’s to understand that we’ll use the component approach in our application project. This is a great way to ensure maintainable code by encapsulation of our behavior logic. Hence, each component will live in a single folder with each concern as a file: style, template, specs, e2e, and component class. Before going further let’s reorganize our files as follow : 1 2 3 4 5 6 7 8 9 10 11 12 angular2-starter/ ├──src/ | ├──bootstrap.ts | ├──index.html │ │ │ └──app/ │ └──app.component.ts │ ├──tsconfig.json └──package.json You should also update the path in bootstrap.ts : 1 2 3 4 5 6 7 8 9 ///<reference path="../node_modules/angular2/typings/browser.d.ts" /> import { bootstrap } from 'angular2/platform/browser'; import { AppComponent } from './app/app.component'; bootstrap(AppComponent) .catch(err => console.log(err)); Great! Now it’s time to dive in into Webpack. 2. Installing and Configuring Webpack Webpack will replace SystemJS that we have used until now, as a module loader. If you need an explanation on what is Webpack for, I highly recommand you to take a look at the official documentation. In short, webpack is a module bundler. “It takes modules with dependencies and generates static assets representing those modules“. Start with installing webpack, webpack-dev-server, and the webpack plugins locally, and save them as project dependencies : 1 2 3 4 5 6 7 8 9 10 # First, remove SystemJS. We don't need it anymore. npm uninstall --save systemjs # Then, install Typescript locally npm install --save typescript # Finally, install webpack npm install --save-dev webpack webpack-dev-server html-webpack-plugin copy-webpack-plugin Now, let’s configure Webpack for our development workflow. For this purpose we’ll create a webpack.config.js. Add the following settings in your config file : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 var path = require('path'); var webpack = require('webpack'); var CopyWebpackPlugin = require('copy-webpack-plugin'); var HtmlWebpackPlugin = require('html-webpack-plugin'); var ENV = process.env.ENV = 'development'; var HOST = process.env.HOST || 'localhost'; var PORT = process.env.PORT || 8080; var metadata = { host: HOST, port: PORT, ENV: ENV }; /* * config */ module.exports = { // static data for index.html metadata: metadata, // Emit SourceMap to enhance debugging devtool: 'source-map', devServer: { // This is required for webpack-dev-server. The path should // be an absolute path to your build destination. outputPath: path.join(__dirname, 'dist') }, // Switch loaders to debug mode debug: true, // Our angular app entry: { 'polyfills': path.resolve(__dirname, "src/polyfills.ts"), 'app': path.resolve(__dirname, "src/bootstrap.ts") }, // Config for our build file output: { path: path.resolve(__dirname, "dist"), filename: '[name].bundle.js', sourcemapFilename: '[name].map' }, resolve: { // Add `.ts` and `.tsx` as a resolvable extension. extensions: ['', '.ts', '.tsx', '.js'] }, module: { loaders: [ // Support for .ts files { test: /\.tsx?$/, loader: 'ts-loader', include: [ path.resolve(__dirname, "./src") ] }, // Support for .html as raw text { test: /\.html$/, loader: 'raw-loader', exclude: [ path.resolve(__dirname, "src/index.html") ] } ] }, plugins: [ // Copy static assets to the build folder new CopyWebpackPlugin([{ from: 'src/assets', to: 'assets' }]), // Generate the index.html new HtmlWebpackPlugin({ template: 'src/index.html' }) ] } The entry specifies the entry files of our Angular application. It will be use by Webpack as the starting point for the bundling process. As you may notice we specify our bootstrap file, but also a new file named polyfills.ts. It will contain all the dependencies needed to run our Angular2 application. Before that, we’ve put those deps directly inside our index.html. They now live in a separate file : 1 2 3 4 5 // polyfills.ts import 'angular2/bundles/angular2-polyfills'; import 'rxjs'; The output tells Webpack what to do after completing the bundling process. In our case, the dist/ directory will be use to output the bundled files named app.bundle.js and polyfills.bundle.js with th following source-map files. The ts-loader is used to transpile our Typescript files that match the defined test regex. In our case it will process all files with a .ts or .tsx extension. The raw-loader is used to support html files as raw text. Hence, we could write our component views in separate files and include them afterward in our components. You need to install them using npm : 1 2 3 npm install --save-dev ts-loader raw-loader The CopyWebpackPlugin is used to copy the static assets into the build folder. Finally, the metadata are used by the HtmlWebpackplugin to generate our index.html file. In the index.html, we use the host and port data to run the webpack dev server in development environment. See how this file has been simplified : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 <!DOCTYPE html> <html> <head> <link rel="stylesheet" href="./assets/css/styles.css" /> </head> <body> <app>Loading...</app> </body> <% if (webpackConfig.metadata.ENV === 'development') { %> <!-- Webpack Dev Server --> <script src="http://<%= webpackConfig.metadata.host %>:<%= webpackConfig.metadata.port %>/webpack-dev-server.js"></script> <% } %> </html> Feel free to add you own stylesheets files under /src/assets/css as I did with my styles.css file. You should now have a project structured like so : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 angular2-starter/ ├──src/ | ├──bootstrap.ts | ├──index.html | ├──polyfills.ts │ │ │ ├──app/ │ │ └──app.component.ts │ │ │ └──assets/ │ └──css/ │ └──styles.css │ ├──tsconfig.json ├──package.json │ └──webpack.config.js We need one more thing to be all set up. As mentionned before, we will write the views in separated file. So, create an app.html file and refer to it in your app.components.ts. 1 2 3 4 <!-- app.html --> <h1>Hello, Angular2</h1> 1 2 3 4 5 6 7 8 9 10 // app.component.ts import { Component } from 'angular2/core'; @Component({ selector: 'app', template: require('./app.html') }) export class AppComponent { } Finally, we have to install the node typings definition to be able to require file inside our component as we did for the view. Hence, to do so run the following commands, and complete the tsconfig.json to exclude some files : 1 2 3 4 5 6 7 8 9 10 # Install Typings CLI utility npm install typings --global # Init the typings.json typings init # Install typings typings install env~node --global --save As you can notice in my tsconfig.json file below, there are some extra options that are Atom IDE specific features. Feel free to read the documentation about it: atom-typescript/tsconfig.json. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 { "compilerOptions": { "target": "es5", "sourceMap": true, "experimentalDecorators": true, "emitDecoratorMetadata": true, "module": "commonjs", "noImplicitAny": false, "outDir": "built", "rootDir": "." }, "exclude": [ "node_modules", "typings/main.d.ts", "typings/main" ], "filesGlob": [ "./src/**/*.ts", "!./node_modules/**/*.ts", "typings/browser.d.ts" ], "compileOnSave": false, "buildOnSave": false } If you want to know more about typings read the following pages on Github : Microsoft/TypeScript and typings/typings. Ok! Now it’s time to build and run our application using Webpack. Let’s create some npm scripts to handle those operations. 3. Using npm as a Task Runner We will simply use npm to define and run our tasks : one for the build process, and one for running the development server. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 { "name": "angular2-starter", "version": "1.0.0", "description": "", "main": "index.js", "scripts": { "build:dev": "webpack --progress --colors", "server:dev": "webpack-dev-server --hot --progress --colors --content-base dist/", "start": "npm run server:dev" }, ... } We can now run npm start and visit http://localhost:8080 to see our app running.

Convert any code into a GeneXus procedure. Get the code of your choice, generate a spec, then use that spec to generate a GeneXus procedure inside an xpz file.

Hyperdrive DCF (Design Cascading Framework) — a top-down methodology for rapid POC generation and idea validation, with every change tracked and synced back to the requirements spec with precision. Validated requirements then cascade through architecture and module specs to generate fully traced, test-gated production code. Powered by Claude Code.

A CLI wizard that turns your landing page vision into structured, AI-ready prompts. Design the spec, then let your AI coding tool build it.

A phased execution harness for coding agents. It sits above Claude Code and orchestrates spec-driven implementation: compiling a plan.md into structured tasks.json, then executing tasks phase-by-phase using an orchestrator subprocess with Claude's native tools and specialized sub-agents. Each phase gets its own context window and is judge gated.

A Claude Code skill that transforms app ideas into production-ready project scaffolds — specs, architecture, agent instructions, no code. Then hand it over to your coding agent.

An AI product-manager agent that turns rough product ideas into structured specs through a 3-phase pipeline: Discovery → Scoping → Spec Writer. It runs a PM-style discovery interview, proposes a RICE-scoped MVP with comparable products, then writes a phased product spec you can hand to a code-gen tool like Emergent, Lovable, Antigravity etc.

A spec-driven orchestration framework where Lily generates structured specifications, plans, and context artifacts, then hands them off to external AI coding agents (Claude, Cursor, etc.). Focused on portability, clarity, and high-quality AI handoffs—without Lily writing code herself.

A sample code snippet from one of my professional projects. I prepared the spec and design document and then implemented the feature. This snapshot only represents the type of development practices I have been involved in.

A simple example of "API First Driven Development" using the OpenAPI and Springboot. A predetermined OpenAPI spec is used to generate a REST Controller Interface and its associated response Models. The generated code is then integrated into the codebase.

Firebase Assignment - Train Scheduler (Basic - Recommended) ##### _Because that Rock Paper Scissors Game is Too Damn Hard_ ### Overview In this assignment, you'll create a train schedule application that incorporates Firebase to host arrival and departure data. Your app will retrieve and manipulate this information with Moment.js. This website will provide up-to-date information about various trains, namely their arrival times and how many minutes remain until they arrive at their station. - - - ### Setup * We'll leave that up to you -- however you like. Just make sure you're using Firebase to store data, GitHub to backup your project, and GitHub Pages to host your finished site. ### Submission on BCS * Please submit both the deployed Github.io link to your homework AND the link to the Github Repository! ### Instructions * Make sure that your app suits this basic spec: * When adding trains, administrators should be able to submit the following: * Train Name * Destination * First Train Time -- in military time * Frequency -- in minutes * Code this app to calculate when the next train will arrive; this should be relative to the current time. * Users from many different machines must be able to view same train times. * Styling and theme are completely up to you. Get Creative! ### Example Site  ### Bonus (Extra Challenges) * Consider updating your "minutes to arrival" and "next train time" text once every minute. This is significantly more challenging; only attempt this if you've completed the actual activity and committed it somewhere on GitHub for safekeeping (and maybe create a second GitHub repo). * Try adding `update` and `remove` buttons for each train. Let the user edit the row's elements-- allow them to change a train's Name, Destination and Arrival Time (and then, by relation, minutes to arrival). * As a final challenge, make it so that only users who log into the site with their Google or GitHub accounts can use your site. You'll need to read up on Firebase authentication for this bonus exercise. ### Reminder: Submission on BCS * Please submit both the deployed Github.io link to your homework AND the link to the Github Repository! - - - ### Minimum Requirements Attempt to complete homework assignment as described in instructions. If unable to complete certain portions, please pseudocode these portions to describe what remains to be completed. Adding a README.md as well as adding this homework to your portfolio are required as well and more information can be found below. - - - ### Create a README.md Add a `README.md` to your repository describing the project. Here are some resources for creating your `README.md`. Here are some resources to help you along the way: * [About READMEs](https://help.github.com/articles/about-readmes/) * [Mastering Markdown](https://guides.github.com/features/mastering-markdown/) - - - ### Add To Your Portfolio After completing the homework please add the piece to your portfolio. Make sure to add a link to your updated portfolio in the comments section of your homework so the TAs can easily ensure you completed this step when they are grading the assignment. To receive an 'A' on any assignment, you must link to it from your portfolio. - - - ### One More Thing If you have any questions about this project or the material we have covered, please post them in the community channels in slack so that your fellow developers can help you! If you're still having trouble, you can come to office hours for assistance from your instructor and TAs. **Good Luck!**

# Firebase Assignment - Train Scheduler (Basic - Recommended) ##### _Because that Rock Paper Scissors Game is Too Damn Hard_ ### Overview In this assignment, you'll create a train schedule application that incorporates Firebase to host arrival and departure data. Your app will retrieve and manipulate this information with Moment.js. This website will provide up-to-date information about various trains, namely their arrival times and how many minutes remain until they arrive at their station. - - - ### Setup * We'll leave that up to you -- however you like. Just make sure you're using Firebase to store data, GitHub to backup your project, and GitHub Pages to host your finished site. ### Submission on BCS * Please submit both the deployed Github.io link to your homework AND the link to the Github Repository! ### Instructions * Make sure that your app suits this basic spec: * When adding trains, administrators should be able to submit the following: * Train Name * Destination * First Train Time -- in military time * Frequency -- in minutes * Code this app to calculate when the next train will arrive; this should be relative to the current time. * Users from many different machines must be able to view same train times. * Styling and theme are completely up to you. Get Creative! ### Example Site  ### Bonus (Extra Challenges) * Consider updating your "minutes to arrival" and "next train time" text once every minute. This is significantly more challenging; only attempt this if you've completed the actual activity and committed it somewhere on GitHub for safekeeping (and maybe create a second GitHub repo). * Try adding `update` and `remove` buttons for each train. Let the user edit the row's elements-- allow them to change a train's Name, Destination and Arrival Time (and then, by relation, minutes to arrival). * As a final challenge, make it so that only users who log into the site with their Google or GitHub accounts can use your site. You'll need to read up on Firebase authentication for this bonus exercise. ### Reminder: Submission on BCS * Please submit both the deployed Github.io link to your homework AND the link to the Github Repository! - - - ### Minimum Requirements Attempt to complete homework assignment as described in instructions. If unable to complete certain portions, please pseudocode these portions to describe what remains to be completed. Adding a README.md as well as adding this homework to your portfolio are required as well and more information can be found below. - - - ### Create a README.md Add a `README.md` to your repository describing the project. Here are some resources for creating your `README.md`. Here are some resources to help you along the way: * [About READMEs](https://help.github.com/articles/about-readmes/) * [Mastering Markdown](https://guides.github.com/features/mastering-markdown/) - - - ### Add To Your Portfolio After completing the homework please add the piece to your portfolio. Make sure to add a link to your updated portfolio in the comments section of your homework so the TAs can easily ensure you completed this step when they are grading the assignment. To receive an 'A' on any assignment, you must link to it from your portfolio. - - - ### One More Thing If you have any questions about this project or the material we have covered, please post them in the community channels in slack so that your fellow developers can help you! If you're still having trouble, you can come to office hours for assistance from your instructor and TAs. **Good Luck!**

(function () { var COMPAT_ENVS = [ ['Firefox', ">= 16.0"], ['Google Chrome', ">= 24.0 (you may need to get Google Chrome Canary), NO Blob storage support"] ]; var compat = $('#compat'); compat.empty(); compat.append('<ul id="compat-list"></ul>'); COMPAT_ENVS.forEach(function(val, idx, array) { $('#compat-list').append('<li>' + val[0] + ': ' + val[1] + '</li>'); }); const DB_NAME = 'mdn-demo-indexeddb-epublications'; const DB_VERSION = 1; // Use a long long for this value (don't use a float) const DB_STORE_NAME = 'publications'; var db; // Used to keep track of which view is displayed to avoid uselessly reloading it var current_view_pub_key; function openDb() { console.log("openDb ..."); var req = indexedDB.open(DB_NAME, DB_VERSION); req.onsuccess = function (evt) { // Better use "this" than "req" to get the result to avoid problems with // garbage collection. // db = req.result; db = this.result; console.log("openDb DONE"); }; req.onerror = function (evt) { console.error("openDb:", evt.target.errorCode); }; req.onupgradeneeded = function (evt) { console.log("openDb.onupgradeneeded"); var store = evt.currentTarget.result.createObjectStore( DB_STORE_NAME, { keyPath: 'id', autoIncrement: true }); store.createIndex('biblioid', 'biblioid', { unique: true }); store.createIndex('title', 'title', { unique: false }); store.createIndex('year', 'year', { unique: false }); }; } /** * @param {string} store_name * @param {string} mode either "readonly" or "readwrite" */ function getObjectStore(store_name, mode) { var tx = db.transaction(store_name, mode); return tx.objectStore(store_name); } function clearObjectStore(store_name) { var store = getObjectStore(DB_STORE_NAME, 'readwrite'); var req = store.clear(); req.onsuccess = function(evt) { displayActionSuccess("Store cleared"); displayPubList(store); }; req.onerror = function (evt) { console.error("clearObjectStore:", evt.target.errorCode); displayActionFailure(this.error); }; } function getBlob(key, store, success_callback) { var req = store.get(key); req.onsuccess = function(evt) { var value = evt.target.result; if (value) success_callback(value.blob); }; } /** * @param {IDBObjectStore=} store */ function displayPubList(store) { console.log("displayPubList"); if (typeof store == 'undefined') store = getObjectStore(DB_STORE_NAME, 'readonly'); var pub_msg = $('#pub-msg'); pub_msg.empty(); var pub_list = $('#pub-list'); pub_list.empty(); // Resetting the iframe so that it doesn't display previous content newViewerFrame(); var req; req = store.count(); // Requests are executed in the order in which they were made against the // transaction, and their results are returned in the same order. // Thus the count text below will be displayed before the actual pub list // (not that it is algorithmically important in this case). req.onsuccess = function(evt) { pub_msg.append('<p>There are <strong>' + evt.target.result + '</strong> record(s) in the object store.</p>'); }; req.onerror = function(evt) { console.error("add error", this.error); displayActionFailure(this.error); }; var i = 0; req = store.openCursor(); req.onsuccess = function(evt) { var cursor = evt.target.result; // If the cursor is pointing at something, ask for the data if (cursor) { console.log("displayPubList cursor:", cursor); req = store.get(cursor.key); req.onsuccess = function (evt) { var value = evt.target.result; var list_item = $('<li>' + '[' + cursor.key + '] ' + '(biblioid: ' + value.biblioid + ') ' + value.title + '</li>'); if (value.year != null) list_item.append(' - ' + value.year); if (value.hasOwnProperty('blob') && typeof value.blob != 'undefined') { var link = $('<a href="' + cursor.key + '">File</a>'); link.on('click', function() { return false; }); link.on('mouseenter', function(evt) { setInViewer(evt.target.getAttribute('href')); }); list_item.append(' / '); list_item.append(link); } else { list_item.append(" / No attached file"); } pub_list.append(list_item); }; // Move on to the next object in store cursor.continue(); // This counter serves only to create distinct ids i++; } else { console.log("No more entries"); } }; } function newViewerFrame() { var viewer = $('#pub-viewer'); viewer.empty(); var iframe = $('<iframe />'); viewer.append(iframe); return iframe; } function setInViewer(key) { console.log("setInViewer:", arguments); key = Number(key); if (key == current_view_pub_key) return; current_view_pub_key = key; var store = getObjectStore(DB_STORE_NAME, 'readonly'); getBlob(key, store, function(blob) { console.log("setInViewer blob:", blob); var iframe = newViewerFrame(); // It is not possible to set a direct link to the // blob to provide a mean to directly download it. if (blob.type == 'text/html') { var reader = new FileReader(); reader.onload = (function(evt) { var html = evt.target.result; iframe.load(function() { $(this).contents().find('html').html(html); }); }); reader.readAsText(blob); } else if (blob.type.indexOf('image/') == 0) { iframe.load(function() { var img_id = 'image-' + key; var img = $('<img id="' + img_id + '"/>'); $(this).contents().find('body').html(img); var obj_url = window.URL.createObjectURL(blob); $(this).contents().find('#' + img_id).attr('src', obj_url); window.URL.revokeObjectURL(obj_url); }); } else if (blob.type == 'application/pdf') { $('*').css('cursor', 'wait'); var obj_url = window.URL.createObjectURL(blob); iframe.load(function() { $('*').css('cursor', 'auto'); }); iframe.attr('src', obj_url); window.URL.revokeObjectURL(obj_url); } else { iframe.load(function() { $(this).contents().find('body').html("No view available"); }); } }); } /** * @param {string} biblioid * @param {string} title * @param {number} year * @param {string} url the URL of the image to download and store in the local * IndexedDB database. The resource behind this URL is subjected to the * "Same origin policy", thus for this method to work, the URL must come from * the same origin as the web site/app this code is deployed on. */ function addPublicationFromUrl(biblioid, title, year, url) { console.log("addPublicationFromUrl:", arguments); var xhr = new XMLHttpRequest(); xhr.open('GET', url, true); // Setting the wanted responseType to "blob" // http://www.w3.org/TR/XMLHttpRequest2/#the-response-attribute xhr.responseType = 'blob'; xhr.onload = function (evt) { if (xhr.status == 200) { console.log("Blob retrieved"); var blob = xhr.response; console.log("Blob:", blob); addPublication(biblioid, title, year, blob); } else { console.error("addPublicationFromUrl error:", xhr.responseText, xhr.status); } }; xhr.send(); // We can't use jQuery here because as of jQuery 1.8.3 the new "blob" // responseType is not handled. // http://bugs.jquery.com/ticket/11461 // http://bugs.jquery.com/ticket/7248 // $.ajax({ // url: url, // type: 'GET', // xhrFields: { responseType: 'blob' }, // success: function(data, textStatus, jqXHR) { // console.log("Blob retrieved"); // console.log("Blob:", data); // // addPublication(biblioid, title, year, data); // }, // error: function(jqXHR, textStatus, errorThrown) { // console.error(errorThrown); // displayActionFailure("Error during blob retrieval"); // } // }); } /** * @param {string} biblioid * @param {string} title * @param {number} year * @param {Blob=} blob */ function addPublication(biblioid, title, year, blob) { console.log("addPublication arguments:", arguments); var obj = { biblioid: biblioid, title: title, year: year }; if (typeof blob != 'undefined') obj.blob = blob; var store = getObjectStore(DB_STORE_NAME, 'readwrite'); var req; try { req = store.add(obj); } catch (e) { if (e.name == 'DataCloneError') displayActionFailure("This engine doesn't know how to clone a Blob, " + "use Firefox"); throw e; } req.onsuccess = function (evt) { console.log("Insertion in DB successful"); displayActionSuccess(); displayPubList(store); }; req.onerror = function() { console.error("addPublication error", this.error); displayActionFailure(this.error); }; } /** * @param {string} biblioid */ function deletePublicationFromBib(biblioid) { console.log("deletePublication:", arguments); var store = getObjectStore(DB_STORE_NAME, 'readwrite'); var req = store.index('biblioid'); req.get(biblioid).onsuccess = function(evt) { if (typeof evt.target.result == 'undefined') { displayActionFailure("No matching record found"); return; } deletePublication(evt.target.result.id, store); }; req.onerror = function (evt) { console.error("deletePublicationFromBib:", evt.target.errorCode); }; } /** * @param {number} key * @param {IDBObjectStore=} store */ function deletePublication(key, store) { console.log("deletePublication:", arguments); if (typeof store == 'undefined') store = getObjectStore(DB_STORE_NAME, 'readwrite'); // As per spec http://www.w3.org/TR/IndexedDB/#object-store-deletion-operation // the result of the Object Store Deletion Operation algorithm is // undefined, so it's not possible to know if some records were actually // deleted by looking at the request result. var req = store.get(key); req.onsuccess = function(evt) { var record = evt.target.result; console.log("record:", record); if (typeof record == 'undefined') { displayActionFailure("No matching record found"); return; } // Warning: The exact same key used for creation needs to be passed for // the deletion. If the key was a Number for creation, then it needs to // be a Number for deletion. req = store.delete(key); req.onsuccess = function(evt) { console.log("evt:", evt); console.log("evt.target:", evt.target); console.log("evt.target.result:", evt.target.result); console.log("delete successful"); displayActionSuccess("Deletion successful"); displayPubList(store); }; req.onerror = function (evt) { console.error("deletePublication:", evt.target.errorCode); }; }; req.onerror = function (evt) { console.error("deletePublication:", evt.target.errorCode); }; } function displayActionSuccess(msg) { msg = typeof msg != 'undefined' ? "Success: " + msg : "Success"; $('#msg').html('<span class="action-success">' + msg + '</span>'); } function displayActionFailure(msg) { msg = typeof msg != 'undefined' ? "Failure: " + msg : "Failure"; $('#msg').html('<span class="action-failure">' + msg + '</span>'); } function resetActionStatus() { console.log("resetActionStatus ..."); $('#msg').empty(); console.log("resetActionStatus DONE"); } function addEventListeners() { console.log("addEventListeners"); $('#register-form-reset').click(function(evt) { resetActionStatus(); }); $('#add-button').click(function(evt) { console.log("add ..."); var title = $('#pub-title').val(); var biblioid = $('#pub-biblioid').val(); if (!title || !biblioid) { displayActionFailure("Required field(s) missing"); return; } var year = $('#pub-year').val(); if (year != '') { // Better use Number.isInteger if the engine has EcmaScript 6 if (isNaN(year)) { displayActionFailure("Invalid year"); return; } year = Number(year); } else { year = null; } var file_input = $('#pub-file'); var selected_file = file_input.get(0).files[0]; console.log("selected_file:", selected_file); // Keeping a reference on how to reset the file input in the UI once we // have its value, but instead of doing that we rather use a "reset" type // input in the HTML form. //file_input.val(null); var file_url = $('#pub-file-url').val(); if (selected_file) { addPublication(biblioid, title, year, selected_file); } else if (file_url) { addPublicationFromUrl(biblioid, title, year, file_url); } else { addPublication(biblioid, title, year); } }); $('#delete-button').click(function(evt) { console.log("delete ..."); var biblioid = $('#pub-biblioid-to-delete').val(); var key = $('#key-to-delete').val(); if (biblioid != '') { deletePublicationFromBib(biblioid); } else if (key != '') { // Better use Number.isInteger if the engine has EcmaScript 6 if (key == '' || isNaN(key)) { displayActionFailure("Invalid key"); return; } key = Number(key); deletePublication(key); } }); $('#clear-store-button').click(function(evt) { clearObjectStore(); }); var search_button = $('#search-list-button'); search_button.click(function(evt) { displayPubList(); }); } openDb(); addEventListeners(); })(); // Immediately-Invoked Function Expression (IIFE)

A Claude Code skill for spec-driven development: requirements → design → tasks, then code.

A spec-first, test-driven development framework for building software with AI coding agents. Define the blueprint, then let agents build to spec.

Cowork skill for spec-driven development — Specify what to build, Plan how to build it, then hand off to Claude Code

Implement PRDs/specs with a mandatory precheck review before coding. Use when a user asks to implement a PRD/feature spec/requirements doc or says "implement PRD/spec". Perform a preflight review, raise questions on scope/consistency/risks, then implement after confirmation.

A simple agentic approach to software development, using a manually created spec document to prompt an AI, whose code is then reviewed by another AI

Visual Studio Code extension to help introducing formatjs into an existing codebase. Select a string or template string then format it automatically to follow formatjs spec.

Gathers top performing builds and weighs each talent based on how common each one is. It then gives you a code to copy for each class/spec

Artifact-first documentation template for LLM-assisted development. Produces a single spec from code/tests/configs, then reconciles with docs. Includes the v1 template and an example URS.