Excalidraw is an open-source, web-based virtual whiteboard and diagramming application. It is used to create diagrams, wireframes, and sketches within a web browser without requiring account registration. The software features a characteristic hand-drawn visual style and supports real-time multi-user collaboration using client-side end-to-end encryption. Excalidraw is released under the MIT License and is maintained by Excalidraw s.r.o., a company based in Brno, Czech Republic. == History == Excalidraw was created on 1 January 2020 by Christopher Chedeau, a software engineer at Meta Platforms. Chedeau, who previously co-created React Native and Prettier, initially developed the application as a personal project before registering the domain on 3 January 2020. Within its first months, the project attracted open-source contributors who assisted in expanding its features and rewriting the codebase into TypeScript and React. By early 2021, day-to-day operations moved to Czech developers David Luzar and Milos Vetesnik. In May 2021, the team incorporated Excalidraw s.r.o. in Brno and launched a commercial cloud-based version named Excalidraw+ to fund the open-source project's development. By May 2026, the main open-source repository on GitHub had accumulated over 123,000 stars. == Features and architecture == The application provides an infinite canvas for geometric shapes, lines, arrows, text, and freehand drawing. Its visual presentation relies on Rough.js, a JavaScript graphics library that alters standard vector paths to mimic irregular, hand-drawn lines. Excalidraw operates as a Progressive web application (PWA), allowing local installation and offline usage, saving data natively to local browser storage. Files use a native, JSON-based extension format (.excalidraw), and canvases can be exported to PNG or SVG formats. Real-time collaboration sessions are executed using Socket.IO via a relay server. Data transmission uses the browser's native Web Cryptography API to achieve end-to-end encryption. A symmetric AES key is generated on the client side and appended to the sharing URL as a fragment identifier (following the # character). Because web browsers do not transmit URL fragments to HTTP servers, the data remains unreadable to the distribution server. == Ecosystem == Excalidraw is distributed as an npm package, allowing third-party developers to embed the whiteboard component directly into external React web applications. Community-developed extensions integrate the application's file format into text editors and note-taking systems, including Visual Studio Code and Obsidian. The platform also has native integrations in commercial platforms such as Notion and HackerRank. == Reception == Google's developer relations team published a technical case study on Excalidraw as a reference implementation for Progressive Web Apps. The analysis highlighted the software's adoption of advanced web platform capabilities, specifically its utilization of the File System Access API and native Clipboard API to replicate desktop software behavior within a web browser environment.
Cepstral mean and variance normalization
Cepstral mean and variance normalization (CMVN) is a computationally efficient normalization technique for robust speech recognition. The performance of CMVN is known to degrade for short utterances. This is due to insufficient data for parameter estimation and loss of discriminable information as all utterances are forced to have zero mean and unit variance. CMVN minimizes distortion by noise contamination for robust feature extraction by linearly transforming the cepstral coefficients to have the same segmental statistics. Cepstral Normalization has been effective in the CMU Sphinx for maintaining a high level of recognition accuracy over a wide variety of acoustical environments. == Cepstral Normalization Techniques == There are multiple algorithms that achieve Cepstral Normalization in different ways. === Fixed codeword-dependent cepstral normalization (FCDCN) === FCDCN was developed to provide a form of compensation that provides greater recognition accuracy than SDCN but in a more computationally-efficient manner than the CDCN algorithm. The FCDCN algorithm applies an additive correction that depends on the instantaneous SNR of the input (like SDCN), but that can also vary from codeword to codeword (like CDCN). === Multiple Fixed Codeword-dependent Cepstral Normalization (MFCDCN) === MFCDCN is a simple extension of FCDCN algorithm that does not need environment specific training. In MFCDCN, compensation vectors are pre-computed in parallel for a set of target environments, using the FCDCN algorithm. === Incremental Multiple Fixed Codeword-dependent Cepstral Normalization (IMFCDCN) === While environment selection for the compensation vectors of MFCDCN is generally performed on an utterance-by-utterance basis, IMFCFCN improves on it by allowing the classification process to make use of cepstral vectors from previous utterances in a given session. == Cepstral Noise Subtraction == Automatic speech recognition (ASR) describes the steps of transcribing speech utterances represented as acoustic wave forms to written words. As is, CMVN has been used in different applications as this technique has proven to provide better speech recognitions results in different environments. CMVN has the capabilities to reduce differences between test and training data produced by channel distortions and colorizations . CMVN has also been found to be able to reduce differences in feature representation between speakers can also partly reduce the influence of background noise.
Source-code editor
A source-code editor is a text editor program designed specifically for editing the source code of computer programs. It includes basic functionality such as syntax highlighting, and sometimes debugging. It may be a standalone application or it may be built into an integrated development environment (IDE). == Features == Source-code editors have features specifically designed to simplify and speed up typing of source code, such as syntax highlighting(syntax error highlighting), auto indentation, autocomplete and brace matching functionality. These editors may also provide a convenient way to run a compiler, interpreter, debugger, or other program relevant for the software-development process. While many text editors like Notepad can be used to edit source code, if they do not enhance, automate or ease the editing of code, they are not defined as source-code editors. Structure editors are a different form of a source-code editor, where instead of editing raw text, one manipulates the code's structure, generally the abstract syntax tree. In this case features such as syntax highlighting, validation, and code formatting are easily and efficiently implemented from the concrete syntax tree or abstract syntax tree, but editing is often more rigid than free-form text. Structure editors also require extensive support for each language, and thus are harder to extend to new languages than text editors, where basic support only requires supporting syntax highlighting or indentation. For this reason, strict structure editors are not popular for source code editing, though some IDEs provide similar functionality. A source-code editor can check syntax dynamically while code is being entered and immediately warn of syntax problems, as well as suggest code autocomplete snippets. A few source-code editors compress source code, typically converting common keywords into single-byte tokens, removing unnecessary whitespace, and converting numbers to a binary form. Such tokenizing editors later uncompress the source code when viewing it, possibly prettyprinting it with consistent capitalization and spacing. A few source-code editors do both. The Language Server Protocol, first used in Microsoft's Visual Studio Code, allows for source code editors to implement an LSP client that can read syntax information about any language with a LSP server. This allows for source code editors to easily support more languages with syntax highlighting, refactoring, and reference finding. Many source code editors such as Neovim and Brackets have added a built-in LSP client while other editors such as Emacs, Vim, and Sublime Text have support for an LSP Client via a separate plug-in. == History == In 1985, Mike Cowlishaw of IBM created LEXX while seconded to the Oxford University Press. LEXX used live parsing and used color and fonts for syntax highlighting. IBM's LPEX (Live Parsing Extensible Editor) was based on LEXX and ran on VM/CMS, OS/2, OS/400, Windows, and Java Although the initial public release of vim was in 1991, the syntax highlighting feature was not introduced until version 5.0 in 1998. On November 1, 2015, the first version of NeoVim was released. In 2003, Notepad++, a source code editor for Windows, was released by Don Ho. The intention was to create an alternative to the java-based source code editor, JEXT In 2015, Microsoft released Visual Studio Code as a lightweight and cross-platform alternative to their Visual Studio IDE. The following year, Visual Studio Code became the Microsoft product using the Language Server Protocol. This code editor quickly gained popularity and emerged as the most widely used source code editor. == Comparison with IDEs == A source-code editor is one component of a Integrated Development Environment. In contrast to a standalone source-code editor, an IDE typically also includes several tools which enhance the software development process. Such tools include syntax highlighting, code autocomplete suggestions, version control, automatic formatting, integrated runtime environments, debugger, and build tools. Standalone source code editors are preferred over IDEs by some developers when they believe the IDEs are bloated with features they do not need. == Notable examples == == Controversy == Many source-code editors and IDEs have been involved in ongoing user arguments, sometimes referred to jovially as "holy wars" by the programming community. Notable examples include vi vs. Emacs and Eclipse vs. NetBeans. These arguments have formed a significant part of internet culture and they often start whenever either editor is mentioned anywhere.
Seed (programming)
Seed is a JavaScript interpreter and a library of the GNOME project to create standalone applications in JavaScript. It uses the JavaScript engine JavaScriptCore of the WebKit project. It is possible to easily create modules in C. Seed is integrated in GNOME since the 2.28 version and is used by two games in the GNOME Games package. It is also used by the Web web browser for the design of its extensions. The module is also officially supported by the GTK+ project. == Hello world in Seed == This example uses the standard output to output the string "Hello, World". == A program using GTK+ == This code shows an empty window named "Example". == Modules == To use a module, just instantiate a class having for name imports. followed by the name of the module respecting the case sensitivity. The modules using GObject Introspection, who starts by imports.gi. : Gtk Gst GObject Gio Clutter GLib Gdk WebKit GdkPixbuf, GdkPixbuf Libxml Cairo DBus MPFR Os (system library) Canvas (using Cairo) multiprocessing readline Archived 2009-11-09 at the Wayback Machine ffi sqlite sandbox Archived 2009-11-09 at the Wayback Machine == List of the Seed versions == The names of the versions of Seed are albums of famous rock bands.
Fuse Mediation Router
Fuse Mediation Router is an open source tool for integrating services using Enterprise Integration Patterns based on Apache Camel for use in enterprise IT organizations. It is certified, productized and fully supported by the people who wrote the code. Fuse Mediation Router uses a standard method of notation to go from diagram to implementation without coding. Fuse Mediation Router is a rule-based routing and process mediation engine that combines the ease of basic POJO development with the clarity of the standard Enterprise Integration Patterns. It can be deployed inside any container or be used stand-alone, and works directly with any kind of transport or messaging model to rapidly integrate existing services and applications. Fuse Mediation Router is now a part of Red Hat JBoss Fuse. == Tooling == FuseSource offers graphical, Eclipse-based tooling for Apache Camel for download.
Web Intents
Web Intents was an experimental framework for web-based inter-application communication and service discovery. Web Intents consists of a discovery mechanism and a very light-weight RPC system between web applications, modelled after the Intents system in Android. In the context of the framework an Intent equals an action to be performed by a provider. Web Intents allow two web applications to communicate with each other, without either of them having to actually know what the other one is. == Support == === Client === Google Chrome versions 18 to 23 natively supported Web Intents. This support was disabled in version 24, citing the existence of a "number of areas for development in both the API and specific user experience in Chrome". There is a JavaScript shim with support for IE 8, IE 9, Opera, Safari, Firefox 3+ and Chrome 3+. === Server === There are some Web Intents proxy pages that make available some real services that don't yet support intents. AddThis supports Web Intents by their sharing tools regardless of browser support. == History == Paul Kinlan of Google announced the Web Intents project in December 2010. He soon released a prototype API to GitHub. In August 2011 Google announced that Chrome would support Web Intents. Google and Mozilla have started co-operating to unify Web Intents and Mozilla's Web Activities (which tries to solve the same problem) into one proposal. In November 2012, Greg Billock of Google announced that experimental support of Web Intents had been removed from Chrome.
Content Disarm and Reconstruction
Content Disarm and Reconstruction (CDR) is a computer security technology for removing potentially malicious code from files. Unlike malware analysis, CDR technology does not determine or detect malware's functionality but removes all file components that are not approved within the system's definitions and policies. It is used to prevent cyber security threats from entering a corporate network perimeter. Channels that CDR can be used to protect include email and website traffic. Advanced solutions can also provide similar protection on computer endpoints, or cloud email and file sharing services. There are three levels of CDR; 1) flattening and converting the original file to a PDF, 2) stripping active content while keeping the original file type, and 3) eliminating all file-borne risk while maintaining file type, integrity and active content. Beyond these three levels, there are also more advanced forms of CDR that is able to perform "soft conversion" and "hard conversion", based on the user's preference in balancing usability and security. == Applications == CDR works by processing all incoming files of an enterprise network, deconstructing them, and removing the elements that do not match the file type's standards or set policies. CDR technology then rebuilds the files into clean versions that can be sent on to end users as intended. Because CDR removes all potentially malicious code, it can be effective against zero-day vulnerabilities that rely on being an unknown threat that other security technologies would need to patch against to maintain protection. CDR can be used to prevent cyber threats from variety of sources: Email Data Diodes Web Browsers Endpoints File Servers FTP Cloud email or webmail programs SMB/CIFS Removable media scanning (CDR Kiosk) CDR can be applied to a variety of file formats including: Images Office documents PDF Audio/video file formats Archives HTML == Open source implementations == DocBleach ExeFilter