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Topic Review
Amazon Elastic Compute Cloud
Amazon Elastic Compute Cloud (EC2) is a part of Amazon.com's cloud-computing platform, Amazon Web Services (AWS), that allows users to rent virtual computers on which to run their own computer applications. EC2 encourages scalable deployment of applications by providing a web service through which a user can boot an Amazon Machine Image (AMI) to configure a virtual machine, which Amazon calls an "instance", containing any software desired. A user can create, launch, and terminate server-instances as needed, paying by the second for active servers – hence the term "elastic". EC2 provides users with control over the geographical location of instances that allows for latency optimization and high levels of redundancy. In November 2010, Amazon switched its own retail website platform to EC2 and AWS.
  • 1.5K
  • 04 Nov 2022
Topic Review
Leela Chess Zero
Leela Chess Zero (abbreviated as LCZero, lc0) is a free, open-source, and deep neural network–based chess engine and distributed computing project. Development has been spearheaded by programmer Gary Linscott, who is also a developer for the Stockfish chess engine. Leela Chess Zero was adapted from the Leela Zero Go engine, which in turn was based on Google's AlphaGo Zero project. One of the purposes of Leela Chess Zero was to verify the methods in the AlphaZero paper as applied to the game of chess. Like Leela Zero and AlphaGo Zero, Leela Chess Zero starts with no intrinsic chess-specific knowledge other than the basic rules of the game. Leela Chess Zero then learns how to play chess by reinforcement learning from repeated self-play, using a distributed computing network coordinated at the Leela Chess Zero website. (As of January 2022), Leela Chess Zero has played over 500 million games against itself, playing around 1 million games every day, and is capable of play at a level that is comparable with Stockfish, the leading conventional chess program.
  • 1.5K
  • 21 Oct 2022
Topic Review
Reduce (Parallel Pattern)
Reduce is a collective communication primitive used in the context of a parallel programming model to combine multiple vectors into one, using an associative binary operator [math]\displaystyle{ \oplus }[/math]. Every vector is present at a distinct processor in the beginning. The goal of the primitive is to apply the operator in the order given by the processor-indices to the vectors until only one is left. The reduction of sets of elements is an integral part of programming models such as Map Reduce, where a function is applied (mapped) to all elements before they are reduced. Other parallel algorithms use reduce as a primary operation to solve more complex problems. The Message Passing Interface implements it in the operations MPI_Reduce and MPI_Allreduce, with the difference that the result is available at one (root) processing unit or all of them. Closely related to reduce is the broadcast operation, which distributes data to all processors. Many reduce algorithms can be used for broadcasting by reverting them and omitting the operator.
  • 1.5K
  • 05 Dec 2022
Topic Review
SAP Converged Cloud
SAP Converged Cloud is a private managed cloud developed and marketed by SAP. It is a set of cloud computing services that offers managed private cloud, based on the OpenStack technology-based public cloud. It is used by SAP's organization for their own internal IT resources to create a mix of different cloud computing environments made up of the Openstack services. It offers compute, storage, and platform services that are accessible to SAP.
  • 1.5K
  • 15 Nov 2022
Topic Review
Proof-of-Work System
A Proof-of-Work (PoW) system (or protocol, or function) is an economic measure to deter denial of service attacks and other service abuses such as spam on a network by requiring some work from the service requester, usually meaning processing time by a computer. The concept was invented by Cynthia Dwork and Moni Naor as presented in a 1993 journal article. The term "Proof of Work" or PoW was first coined and formalized in a 1999 paper by Markus Jakobsson and Ari Juels. An early example of the proof-of-work system used to give value to a currency is the shell money of the Solomon Islands. A key feature of these schemes is their asymmetry: the work must be moderately hard (but feasible) on the requester side but easy to check for the service provider. This idea is also known as a CPU cost function, client puzzle, computational puzzle or CPU pricing function. It is distinct from a CAPTCHA, which is intended for a human to solve quickly, rather than a computer. Proof of space (PoSpace) proposals apply the same principle by proving a dedicated amount of memory or disk space instead of CPU time. Proof-of-Stake, Proof of bandwidth, and other approaches have been discussed in the context of cryptocurrency. Proof of ownership aims at proving that specific data are held by the prover.
  • 1.4K
  • 07 Nov 2022
Topic Review
Atomic Commit
In the field of computer science, an atomic commit is an operation that applies a set of distinct changes as a single operation. If the changes are applied, then the atomic commit is said to have succeeded. If there is a failure before the atomic commit can be completed, then all of the changes completed in the atomic commit are reversed. This ensures that the system is always left in a consistent state. The other key property of isolation comes from their nature as atomic operations. Isolation ensures that only one atomic commit is processed at a time. The most common uses of atomic commits are in database systems and version control systems. The problem with atomic commits is that they require coordination between multiple systems. As computer networks are unreliable services, this means no algorithm can coordinate with all systems as proven in the Two Generals Problem. As databases become more and more distributed, this coordination will increase the difficulty of making truly atomic commits.
  • 1.4K
  • 07 Nov 2022
Topic Review
WebRTC
WebRTC (Web Real-Time Communication) is a free and open-source project providing web browsers and mobile applications with real-time communication (RTC) via application programming interfaces (APIs). It allows audio and video communication to work inside web pages by allowing direct peer-to-peer communication, eliminating the need to install plugins or download native apps. Supported by Apple, Google, Microsoft, Mozilla, and Opera, WebRTC specifications have been published by the World Wide Web Consortium (W3C) and the Internet Engineering Task Force (IETF). According to the webrtc.org website, the purpose of the project is to "enable rich, high-quality RTC applications to be developed for the browser, mobile platforms, and IoT devices, and allow them all to communicate via a common set of protocols".
  • 1.4K
  • 25 Oct 2022
Topic Review Video Peer Reviewed
Multi-Criteria Decision Making (MCDM) Methods and Concepts
Multi-criteria decision-making (MCDM) is one of the main decision-making problems which aims to determine the best alternative by considering more than one criterion in the selection process. MCDM has manifold tools and methods that can be applied in different fields from finance to engineering design. This entry aims to provide a survey on the MCDM concept, its applications, main categories, and different methods. The final section provides manifold information and statistics on the published works in the MCDM fields. Some of the main methods are also listed in this section.
  • 1.3K
  • 10 Jan 2023
Topic Review
Windows 9X
Windows 9x is a generic term referring to a series of Microsoft Windows computer operating systems produced from 1995 to 2000, which were based on the Windows 95 kernel and its underlying foundation of MS-DOS, both of which were updated in subsequent versions. The first version in the 9x series was Windows 95, which was succeeded by Windows 98 and then Windows Me, which was the third and last version of Windows on the 9x line, until the series was superseded by Windows XP. Windows 9x is predominantly known for its use in home desktops. In 1998, Windows made up 82% of operating system market share. Internal release versions for versions of Windows 9x are 4.x. The internal versions for Windows 95, 98, and Me are 4.0, 4.1, and 4.9, respectively. Previous MS-DOS-based versions of Windows used version numbers of 3.2 or lower. Windows NT, which was aimed at professional users such as networks and businesses, used a similar but separate version number between 3.1 and 4.0. All versions of Windows from Windows XP onwards are based on the Windows NT codebase.
  • 1.3K
  • 30 Nov 2022
Topic Review
Clipboard (Computing)
The clipboard is a buffer that some operating systems provide for short-term storage and transfer within and between application programs. The clipboard is usually temporary and unnamed, and its contents reside in the computer's RAM. The clipboard provides an application programming interface by which programs can specify cut, copy and paste operations. It is left to the program to define methods for the user to command these operations, which may include keybindings and menu selections. When an element is copied or cut, the clipboard must store enough information to enable a sensible result no matter where the element is pasted. Application programs may extend the clipboard functions that the operating system provides. A clipboard manager may give the user additional control over the clipboard. Specific clipboard semantics vary among operating systems, can also vary between versions of the same system, and can sometimes be changed by programs and by user preferences. Windows, Linux and macOS support a single clipboard transaction.
  • 1.3K
  • 19 Oct 2022
Topic Review
Random Number Generation
Ever since the antiquity, random number generation has played an important role both in common everyday life activities, such as leisure games, as well as in the advancement of science. Such means as dice and coins have been employed since the ancient times in order to generate random numbers that were used for gambling, dispute resolution, leisure games, and perhaps even fortune-telling. The theory behind the generation of random numbers, as well as the ability to potentially predict the outcome of this process, has been heavily studied and exploited by mathematics, in an attempt to either ensure the randomness of the process, to gain an advantage in correctly predicting its future outcomes, or to approximate the results of rather complicated computations. Especially in cryptography, random numbers are used due to the aforementioned properties, so that attackers have no other option but to guess the secret. This fact, in conjunction with the ongoing digitalisation of our world, has led to an interest in random number generation within the framework of computer science. In this context, random number generation systems are classified into two main categories: pseudorandom number generators and true random number generators, with the former generating sequences of numbers that appear to be random, but are in fact completely predictable when the initial value (being referred to as the seed) and conditions used for the number generation process are known, and with the latter generating truly random sequences of numbers that can only be predicted (correctly) with negligible probability, even if the initial value and conditions are known. 
  • 1.2K
  • 24 Mar 2023
Topic Review
Cryptography: From Ancient Secrets to Modern Encryption
This research explores the fascinating history of cryptography from its earliest origins to the modern era of digital encryption. It covers the development of various encryption methods throughout history, including substitution and transposition ciphers, the Enigma machine, and the birth of modern cryptography in the computer age. The research also discusses the breakthroughs in public key cryptography and emerging technologies such as quantum cryptography. Additionally, it highlights the pioneers in the field, including Alan Turing and Claude Shannon, and provides advice for those seeking to become experts in cryptography. Despite ongoing debates over encryption and privacy, cryptography remains an essential tool for protecting sensitive information and ensuring the privacy of individuals and organizations around the world.
  • 1.2K
  • 22 May 2023
Topic Review
Timeline of DOS Operating Systems
This article presents a timeline of events in the history of 16-bit x86 DOS-family disk operating systems from 1980 to present. Non-x86 operating systems named "DOS" are not part of the scope of this timeline. Also presented is a timeline of events in the history of the 8-bit 8080-based and 16-bit x86-based CP/M operating systems from 1974 to 2014, as well as the hardware and software developments from 1973 to 1995 which formed the foundation for the initial version and subsequent enhanced versions of these operating systems.
  • 1.2K
  • 26 Oct 2022
Topic Review
Mobile Web
The mobile web, also known as mobile internet, refers to browser-based Internet services accessed from handheld mobile devices, such as smartphones or feature phones, through a mobile or other wireless network. Traditionally, the World Wide Web has been accessed via fixed-line services on laptops and desktop computers. However, the web is now more accessible by portable and wireless devices. An early 2010 ITU (International Telecommunication Union) report said that with current growth rates, web access by people on the go – via laptops and smart mobile devices – is likely to exceed web access from desktop computers within the next five years. In January 2014, mobile internet use exceeded desktop use in the United States. The shift to mobile web access has accelerated since 2007 with the rise of larger multitouch smartphones, and since 2010 with the rise of multitouch tablet computers. Both platforms provide better Internet access, screens, and mobile browsers, or application-based user web experiences, than previous generations of mobile devices. Web designers may work separately on such pages, or pages may be automatically converted, as in Mobile Wikipedia. Faster speeds, smaller, feature-rich devices, and a multitude of applications continue to drive explosive growth for mobile internet traffic. The 2017 Virtual Network Index (VNI) report produced by Cisco Systems forecasts that by 2021, there will be 5.5 billion global mobile users (up from 4.9 billion in 2016). Additionally, the same 2017 VNI report forecasts that average access speeds will increase by roughly 3 times from 6.8 Mbit/s to 20 Mbit/s in that same time span with video comprising the bulk of the traffic (78%). The distinction between mobile web applications and native applications is anticipated to become increasingly blurred, as mobile browsers gain direct access to the hardware of mobile devices (including accelerometers and GPS chips), and the speed and abilities of browser-based applications improve. Persistent storage and access to sophisticated user interface graphics functions may further reduce the need for the development of platform-specific native applications. The mobile web has also been called Web 3.0, drawing parallels to the changes users were experiencing as Web 2.0 websites proliferated. Mobile web access today still suffers from interoperability and usability problems. Interoperability issues stem from the platform fragmentation of mobile devices, mobile operating systems, and browsers. Usability problems are centered on the small physical size of the mobile phone form factors (limits on display resolution and user input/operating). Despite these shortcomings, many mobile developers choose to create apps using mobile web. A June 2011 research on mobile development found mobile web the third most used platform, trailing Android and iOS. In an article in Communications of the ACM in April 2013, Web technologist Nicholas C. Zakas, noted that mobile phones in use in 2013 were more powerful than Apollo 11's 70 lb (32 kg) Apollo Guidance Computer used in the July 1969 lunar landing. However, in spite of their power, in 2013, mobile devices still suffer from web performance with slow connections similar to the 1996 stage of web development. Mobile devices with slower download request/response times, the latency of over-the-air data transmission, with "high-latency connections, slower CPUs, and less memory" force developers to rethink web applications created for desktops with "wired connections, fast CPUs, and almost endless memory." The mobile web was first popularized by a silicon valley company known as Unwired Planet. In 1997, Unwired Planet, Nokia, Ericsson, and Motorola started the WAP Forum to create and harmonize the standards to ease the transition to bandwidth networks and small display devices. The WAP standard was built on a three-layer, middleware architecture that fueled the early growth of the mobile web, but was made virtually irrelevant with faster networks, larger displays, and advanced smartphones based on Apple's iOS and Google's Android software.
  • 1.2K
  • 09 Nov 2022
Topic Review
Bayesian Nonlinear Mixed Effects Models
Nonlinear mixed effects models have become a standard platform for analysis when data is in the form of continuous and repeated measurements of subjects from a population of interest, while temporal profiles of subjects commonly follow a nonlinear tendency. While frequentist analysis of nonlinear mixed effects models has a long history, Bayesian analysis of the models has received comparatively little attention until the late 1980s, primarily due to the time-consuming nature of Bayesian computation. Since the early 1990s, Bayesian approaches for the models began to emerge to leverage rapid developments in computing power, and have recently received significant attention due to (1) superiority to quantify the uncertainty of parameter estimation; (2) utility to incorporate prior knowledge into the models; and (3) flexibility to match exactly the increasing complexity of scientific research arising from diverse industrial and academic fields. 
  • 1.1K
  • 23 Mar 2022
Topic Review
Notation for Theoretic Scheduling Problems
A convenient notation for theoretic scheduling problems was introduced by Ronald Graham, Eugene Lawler, Jan Karel Lenstra and Alexander Rinnooy Kan in. It consists of three fields: α, β and γ. Each field may be a comma separated list of words. The α field describes the machine environment, β the job characteristics and constraints, and γ the objective function. Since its introduction in the late 1970s the notation has been constantly extended, sometimes inconsistently. As a result, today there are some problems that appear with distinct notations in several papers.
  • 1.1K
  • 20 Oct 2022
Topic Review
Associative Classification Method
Machine learning techniques are ever prevalent as datasets continue to grow daily. Associative classification (AC), which combines classification and association rule mining algorithms, plays an important role in understanding big datasets that generate a large number of rules. Clustering, on the other hand, can contribute by reducing the rule space to produce compact models. 
  • 1.1K
  • 20 Sep 2022
Topic Review
Copy and Paste Programming
Copy-and-paste programming, sometimes referred to as just 'pasting', is the production of highly repetitive computer programming code, as produced by copy and paste operations. It is primarily a pejorative term; those who use the term are often implying a lack of programming competence. It may also be the result of technology limitations (e.g., an insufficiently expressive development environment) as subroutines or libraries would normally be used instead. However, there are occasions when copy and paste programming is considered acceptable or necessary, such as for boilerplate, loop unrolling (when not supported automatically by the compiler), or certain programming idioms, and it is supported by some source code editors in the form of snippets.
  • 1.1K
  • 28 Oct 2022
Topic Review
Convolutional Sparse Coding
The convolutional sparse coding paradigm is an extension of the global Sparse Coding model, in which a redundant dictionary is modeled as a concatenation of circulant matrices. While the global sparsity constraint describes signal [math]\displaystyle{ \mathbf{x}\in \mathbb{R}^{N} }[/math] as a linear combination of a few atoms in the redundant dictionary [math]\displaystyle{ \mathbf{D}\in\mathbb{R}^{N\times M}, M\gg N }[/math], usually expressed as [math]\displaystyle{ \mathbf{x}=\mathbf{D}\mathbf{\Gamma} }[/math] for a sparse vector [math]\displaystyle{ \mathbf{\Gamma}\in \mathbb{R}^{M} }[/math], the alternative dictionary structure adopted by the Convolutional Sparse Coding model allows the sparsity prior to be applied locally instead of globally: independent patches of [math]\displaystyle{ \mathbf{x} }[/math] are generated by "local" dictionaries operating over stripes of [math]\displaystyle{ \mathbf{\Gamma} }[/math]. The local sparsity constraint allows stronger uniqueness and stability conditions than the global sparsity prior, and has shown to be a versatile tool for inverse problems in fields such as Image Understanding and Computer Vision. Also, a recently proposed multi-layer extension of the model has shown conceptual benefits for more complex signal decompositions, as well as a tight connection the Convolutional Neural Networks model, allowing a deeper understanding of how the latter operates.
  • 1.1K
  • 24 Nov 2022
Topic Review
Microsoft HoloLens
Microsoft HoloLens, known under development as Project Baraboo, are a pair of mixed reality smartglasses developed and manufactured by Microsoft. HoloLens was the first head-mounted display running the Windows Mixed Reality platform under the Windows 10 computer operating system. The tracking technology used in HoloLens can trace its lineage to Kinect, an add-on for Microsoft's Xbox game console that was introduced in 2010. The pre-production version of HoloLens, the Development Edition, shipped on March 30, 2016, and is targeted to developers in the United States and Canada for a list price of $3000 which allowed hobbyist, professionals, and corporations to participate in the pre-production version of HoloLens. Samsung and Asus have extended an offer to Microsoft to help produce their own mixed-reality products, in collaboration with Microsoft, based around the concept and hardware on HoloLens. On October 12, 2016, Microsoft announced global expansion of HoloLens and publicized that HoloLens would be available for preorder in Australia, Ireland, France, Germany, New Zealand and the United Kingdom. There is also a Commercial Suite (similar to a pro edition of Windows), with enterprise features, such as BitLocker security. As of May 2017, The Suite sold for US$5,000. Microsoft has decided to rent the Hololens without clients making the full investment. Microsoft partners with a company called Abcomrents to give the service of Hololens rental. HoloLens 2 was announced at the Mobile World Congress (MWC) in Barcelona, Spain, on February 24, 2019, and was available on preorder at US$3,500.
  • 1.0K
  • 29 Sep 2022
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