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Topic Review
Context of Computational Complexity
In computational complexity theory and analysis of algorithms, a number of metrics are defined describing the resources, such as time or space, that a machine needs to solve a particular problem. Interpreting these metrics meaningfully requires context, and this context is frequently implicit and depends on the field and the problem under consideration. This article describes a number of important pieces of context and how they affect metrics.
  • 751
  • 28 Oct 2022
Topic Review
Rayman Activity Centre
Rayman is a franchise of platform video games, published by Ubisoft. Since the release of the original Rayman, conceived by Michel Ancel in 1995, the series has produced a total of 45 games across multiple platforms. The series is set in a fantastical, magical world which features a wide range of environments that are very often based on certain themes, such as "the Eraser Plains", a landscape made entirely of stationery. The core games of the series are platformers, but there are several spin-off titles in other genres. The protagonist is the eponymous Rayman, a magical being renowned for his courage and determination who, with the help of his friends, must save his world from various villains.
  • 751
  • 22 Nov 2022
Topic Review
Archy
Archy is a software system whose user interface introduced a different approach for interacting with computers with respect to traditional graphical user interfaces. Designed by human-computer interface expert Jef Raskin, it embodies his ideas and established results about human-centered design described in his book The Humane Interface. These ideas include content persistence, modelessness, a nucleus with commands instead of applications, navigation using incremental text search, and a zooming user interface (ZUI). The system was being implemented at the Raskin Center for Humane Interfaces under Raskin's leadership. Since his death in February 2005 the project was continued by his team, which later shifted focus to the Ubiquity extension for the Firefox browser. Archy in large part builds on Raskin's earlier work with the Apple Macintosh, Canon Cat, SwyftWare, and Ken Perlin's Pad ZUI system. It can be described as a combination of Canon Cat's text processing functions with a modern ZUI. Archy is more radically different from established systems than are Sun Microsystems' Project Looking Glass and Microsoft Research's "Task Gallery" prototype. While these systems build upon the WIMP desktop paradigm, Archy has been compared as similar to the Emacs text editor, although its design begins from a clean slate. Archy used to be called The Humane Environment ("THE"). On January 1, 2005, Raskin announced the new name, and that Archy would be further developed by the non-profit Raskin Center for Humane Interfaces. The name "Archy" is a play on the Center's acronym, R-CHI. It is also an allusion to Don Marquis' archy and mehitabel poetry. Jef Raskin jokingly stated: "Yes, we named our software after a bug" (a cockroach), further playing with the meaning of bugs in software.
  • 743
  • 24 Oct 2022
Topic Review
Domain Name Auction
A domain name auction facilitates the buying and selling of currently registered domain names, enabling individuals to purchase a previously registered domain that suits their needs from an owner wishing to sell. A Drop registrar offers sales of expiring domains; but with a domain auction there is no need to wait until (and if) a current owner allows the registration to lapse before purchasing the domain you most want to own. Domain auction sites allow users to search multiple domain names that are listed for sale by owner, and to place bids on the names they want to purchase. As in any auction, the highest bidder wins. The more desirable a domain name, the higher the winning bid, and auction sites often provide links to escrow agents to facilitate the safe transfer of funds and domain properties between the auctioning parties.
  • 743
  • 21 Nov 2022
Topic Review
Bayesian Inference in Motor Learning
Bayesian inference is a statistical tool that can be applied to motor learning, specifically to adaptation. Adaptation is a short-term learning process involving gradual improvement in performance in response to a change in sensory information. Bayesian inference is used to describe the way the nervous system combines this sensory information with prior knowledge to estimate the position or other characteristics of something in the environment. Bayesian inference can also be used to show how information from multiple senses (e.g. visual and proprioception) can be combined for the same purpose. In either case, Bayesian inference dictates that the estimate is most influenced by whichever information is most certain.
  • 741
  • 27 Oct 2022
Topic Review
Illuminating Ecuador's Data Revolution
In the era of data-driven decision-making, Ecuador stands poised at the forefront of a transformative revolution, embracing data analysis to unveil the untapped potential of its knowledge landscape. This pioneering work delves into the depths of Ecuador's data ecosystem, exploring the vast applications and profound impact of data analysis on the nation's society, education, and industry.
  • 739
  • 03 Aug 2023
Topic Review
Keyword-Based Trust Management System for Fog Computing
Many companies have seen dramatic changes because of cloud computing. This is particularly true given the rapid increase in the use of enormous data sets. Meanwhile, there has been a meteoric increase in demand for private services. The proliferation of Internet of Things (IoT) devices and the increasing demand for low-latency applications have led to the rise of fog computing as a solution for decentralized data processing. Malicious nodes, unauthorized access, and data breaches can compromise the integrity and reliability of data processing. Therefore, there is a solid motivation to address these gaps in trust management and enhance the overall security of fog computing. Optimizing network performance and reducing latency is crucial to ensuring a seamless user experience in fog computing. Improving the efficiency of data transmission and communication among fog nodes can significantly enhance the performance of fog computing networks.
  • 736
  • 18 Aug 2023
Topic Review
Macintosh Toolbox
The Macintosh Toolbox implements many of the high-level features of the Classic Mac OS, including a set of application programming interfaces for software development on the platform. The Toolbox consists of a number of "managers," software components such as QuickDraw, responsible for drawing onscreen graphics, and the Menu Manager, which maintain data structures describing the menu bar. As the original Macintosh was designed without virtual memory or memory protection, it was important to classify code according to when it should be loaded into memory or kept on disk, and how it should be accessed. The Toolbox consists of subroutines essential enough to be permanently kept in memory and accessible by a two-byte machine instruction; however it excludes core "kernel" functionality such as memory management and the file system. Note that the Toolbox does not draw the menu onscreen: menus were designed to have a customizable appearance, so the drawing code was stored in a resource, which could be on a disk.
  • 731
  • 14 Nov 2022
Topic Review
Shift (Command)
This article presents a list of commands used by DOS operating systems, especially as used on x86-based IBM PC compatibles (PCs). Other DOS operating systems are not part of the scope of this list. In DOS, many standard system commands were provided for common tasks such as listing files on a disk or moving files. Some commands were built into the command interpreter, others existed as external commands on disk. Over the several generations of DOS, commands were added for the additional functions of the operating system. In the current Microsoft Windows operating system, a text-mode command prompt window, cmd.exe, can still be used.
  • 731
  • 18 Nov 2022
Topic Review
Real-Time Sensing in Smart Cities
To aid urban planners and residents in understanding the nuances of day-to-day urban dynamics, we actively pursue the improvement of data visualisation tools that can adapt to changing conditions. An architecture was created and implemented that ensures secure and easy connectivity between various sources, such as a network of Internet of Things (IoT) devices, to merge with crowdsensing data and use them efficiently.
  • 731
  • 21 Feb 2024
Topic Review
Enterprise Client-server Backup
Enterprise client-server" backup software describes a class of software applications that back up data from a variety of client computers centrally to one or more server computers, with the particular needs of enterprises in mind. They may employ a scripted client–server backup model with a backup server program running on one computer, and with small-footprint client programs (referred to as "agents" in some applications) running on the other computer(s) being backed up—or alternatively as another process on the same computer as the backup server program. Enterprise-specific requirements include the need to back up large amounts of data on a systematic basis, to adhere to legal requirements for the maintenance and archiving of files and data, and to satisfy short-recovery-time objectives. To satisfy these requirements (which World Backup Day (31 March) highlights), it is typical for an enterprise to appoint a backup administrator—who is a part of office administration rather than of the IT staff and whose role is "being the keeper of the data". In a client-server backup application, the server program initiates the backup activity by the client program. This is distinct from a "personal" backup application such as Apple's Time Machine, in which "Time Machine runs on each Mac, independently of any other Macs, whether they're backing up to the same destination or a different one." If the backup server and client programs are running on separate computers, they are connected in either a single platform or a mixed platform network. The client-server backup model was originated when magnetic tape was the only financially-feasible storage medium for doing backups of multiple computers onto a single archive file;[note 1][note 2] because magnetic tape is a sequential access medium, it was imperative (barring "multiplexed backup") that the client computers be backed up one at a time—as initiated by the backup server program. What is described in the preceding paragraph is the "two-tier" configuration (in one application's diagram, the second-tier backup server program is named "server" preceded by the name of the application, and first-tier "agents" are backing up interactive server applications). That configuration controls the backup server program via either an integrated GUI or a separate Administration Console. In some client-server backup applications, a "three-tier" configuration splits off the backup and restore functions of the server program to run on what are called media servers—computers to which devices containing archive files are attached either locally or as Network-attached storage (NAS). In those applications, the decision on which media server a script is to run on is controlled using another program called either a master server or an optional central admin. server.
  • 728
  • 14 Oct 2022
Topic Review
Commutation Theorem
In mathematics, a commutation theorem explicitly identifies the commutant of a specific von Neumann algebra acting on a Hilbert space in the presence of a trace. The first such result was proved by Francis Joseph Murray and John von Neumann in the 1930s and applies to the von Neumann algebra generated by a discrete group or by the dynamical system associated with a measurable transformation preserving a probability measure. Another important application is in the theory of unitary representations of unimodular locally compact groups, where the theory has been applied to the regular representation and other closely related representations. In particular this framework led to an abstract version of the Plancherel theorem for unimodular locally compact groups due to Irving Segal and Forrest Stinespring and an abstract Plancherel theorem for spherical functions associated with a Gelfand pair due to Roger Godement. Their work was put in final form in the 1950s by Jacques Dixmier as part of the theory of Hilbert algebras. It was not until the late 1960s, prompted partly by results in algebraic quantum field theory and quantum statistical mechanics due to the school of Rudolf Haag, that the more general non-tracial Tomita–Takesaki theory was developed, heralding a new era in the theory of von Neumann algebras.
  • 728
  • 18 Oct 2022
Topic Review
Visiting Heritage Sites in AR and VR
Advances in digitization technologies have made possible the digitization of entire archaeological sites through a combination of technologies, including aerial photogrammetry, terrestrial photogrammetry, and terrestrial laser scanning. At the same time, the evolution of computer algorithms for data processing and the increased processing power made possible the combination of data from multiple scans to create a synthetic representation of large-scale sites.  This route was opened by the gaming industry. In terms of research, the exploitation of these new assets in conjunction with new visual rendering technologies, such as virtual and augmented reality, can create new dimensions for education and leisure.
  • 727
  • 25 Jan 2024
Topic Review
Jem The Bee
JEM, the BEE is a Java, cloud-aware application which implements a Batch Execution Environment, to help and manage the execution of jobs, described by a Job Control Language (JCL). JEM, the BEE performs the following functions:
  • 720
  • 14 Oct 2022
Topic Review
Named Data Networking: Nuts and Bolts
Named Data Networking (NDN) is an implementation of Information-Centric Networking (ICN) that has emerged as a promising candidate for the Future Internet Architecture (FIA). In contrast to traditional networking protocols, NDN’s focus is on content, rather than the source of the content.
  • 720
  • 15 May 2023
Topic Review
Serial Number Arithmetic
Many protocols and algorithms require the serialization or enumeration of related entities. For example, a communication protocol must know whether some packet comes "before" or "after" some other packet. The IETF (Internet Engineering Task Force) RFC 1982 attempts to define "Serial Number Arithmetic" for the purposes of manipulating and comparing these sequence numbers. This task is rather more complex than it might first appear, because most algorithms use fixed size (binary) representations for sequence numbers. It is often important for the algorithm not to "break down" when the numbers become so large that they are incremented one last time and "wrap" around their maximum numeric ranges (go instantly from a large positive number to 0, or a large negative number). Unfortunately, some protocols choose to ignore these issues, and simply use very large integers for their counters, in the hope that the program will be replaced (or they will retire), before the problem occurs (see Y2K). Many communication protocols apply serial number arithmetic to packet sequence numbers in their implementation of a sliding window protocol. Some versions of TCP use protection against wrapped sequence numbers (PAWS). PAWS applies the same serial number arithmetic to packet timestamps, using the timestamp as an extension of the high-order bits of the sequence number.
  • 719
  • 11 Oct 2022
Topic Review
Open Science Data
Open science data or Open Research Data is a type of open data focused on publishing observations and results of scientific activities available for anyone to analyze and reuse. A major purpose of the drive for open data is to allow the verification of scientific claims, by allowing others to look at the reproducibility of results, and to allow data from many sources to be integrated to give new knowledge. While the idea of open science data has been actively promoted since the 1950s, the rise of the Internet has significantly lowered the cost and time required to publish or obtain data.
  • 718
  • 19 Oct 2022
Topic Review
Meiko Scientific
Meiko Scientific Ltd. was a British supercomputer company based in Bristol, founded by members of the design team working on the Inmos transputer microprocessor.
  • 716
  • 11 Oct 2022
Topic Review
Terminus (Video Game)
Terminus is a space-flight role-playing action video game by Vicarious Visions. It was released in 2000 for Microsoft Windows, Linux, and Apple Macintosh. Terminus won awards in the 1999 Independent Games Festival for "Technical Excellence" and "Innovation in Audio".
  • 710
  • 14 Oct 2022
Topic Review
CALL (DOS Command)
This article presents a list of commands used by DOS operating systems, especially as used on x86-based IBM PC compatibles (PCs). Other DOS operating systems are not part of the scope of this list. In DOS, many standard system commands were provided for common tasks such as listing files on a disk or moving files. Some commands were built into the command interpreter, others existed as external commands on disk. Over the several generations of DOS, commands were added for the additional functions of the operating system. In the current Microsoft Windows operating system, a text-mode command prompt window, cmd.exe, can still be used.
  • 709
  • 10 Oct 2022
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