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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Timeline of Computing 1980–89
This article presents a detailed timeline of events in the history of computing from 1980 to 1989. For narratives explaining the overall developments, see the History of computing.
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  • 17 Oct 2022
Topic Review
Sakurai's Bell Inequality
The intention of a Bell inequality is to serve as a test of local realism or local hidden variable theories as against quantum mechanics, applying Bell's theorem, which shows them to be incompatible. Not all the Bell's inequalities that appear in the literature are in fact fit for this purpose. The one discussed here holds only for a very limited class of local hidden variable theories and has never been used in practical experiments. It is, however, discussed by John Bell in his "Bertlmann's socks" paper (Bell, 1981), where it is referred to as the "Wigner–d'Espagnat inequality" (d'Espagnat, 1979; Wigner, 1970). It is also variously attributed to Bohm (1951?) and Belinfante (1973). Note that the inequality is not really applicable either to electrons or photons, since it builds in no probabilistic properties in the measurement process. Much more realistic hidden variable theories can be devised, modelling spin (or polarisation, in optical Bell tests) as a vector and allowing for the fact that not all emitted particles will be detected.
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Topic Review
Behavioral Operations Research
Behavioral operations research (BOR) examines and takes into consideration human behavior and emotions when facing complex decision problems. BOR is part of Operational Research. BOR relates to the behavioural aspects of the use of operations research in problem solving and decision support. Specifically, it focuses on understanding behaviour in, with and beyond models. The general purpose is to make better use and improve the use of operations research theories and practice, so that the benefits received from the potential improvements to operations research approaches in practice, that arise from recent findings in behavioural sciences, are realised . BOR approaches have heavily influenced supply chain management research, amongst others.
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Topic Review
Wireless Gigabit Alliance
The Wireless Gigabit Alliance (WiGig) was a trade association that developed and promoted the adoption of multi-gigabit per second speed wireless communications technology operating over the unlicensed 60 GHz frequency band. The alliance was subsumed by the Wi-Fi Alliance in March 2013. The formation of the WiGig alliance to promote the IEEE 802.11ad protocol was announced in May 2009. The completed version 1.0 WiGig specification was announced in December 2009. In May 2010, WiGig announced the publication of its specification, the opening of its Adopter Program, and the liaison agreement with the Wi-Fi Alliance to cooperate on the expansion of Wi-Fi technologies. In June 2011, WiGig announced the release of its certification-ready version 1.1 specification. The WiGig specification allows devices to communicate without wires at multi-gigabit speeds. It enables high performance wireless data, display and audio applications that supplement the capabilities of previous wireless LAN devices. WiGig tri-band enabled devices, which operate in the 2.4, 5 and 60 GHz bands, deliver data transfer rates up to 7 Gbit/s, about as fast as an 8-band 802.11ac transmission, and more than 11 times faster than the highest 802.11n rate, while maintaining compatibility with existing Wi-Fi devices. The 60 GHz signal cannot typically penetrate walls but can propagate off reflections from walls, ceilings, floors and objects using beamforming built into the WiGig system. When roaming away from the main room, the protocol can switch to make use of the other lower bands at a much lower rate, both of which can propagate through walls.
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Topic Review
Pig-Footed Bandicoot
The pig-footed bandicoot (Chaeropus ecaudatus) was a small marsupial of the arid and semi-arid plains of Australia . The distribution range of the species was later reduced to an inland desert region, where it was last recorded in the 1950s; it is now presumed to be extinct.
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  • 18 Oct 2022
Topic Review
Passive Electrolocation in Fish
Passive electrolocation is a process where certain species of fish or aquatic amphibians can detect electric fields using specialized electroreceptors to detect and to locate the source of an external electric field in its environment creating the electric field. These external electric fields can be produced by any bioelectrical process in an organism, especially by actions of the nerves or muscles of fish, or indeed by the specially developed electric organs of fish. Other fields are induced by movement of a conducting organism through the earth's magnetic field, or from atmospheric electricity. Electrolocating fish use this ability to detect prey, locate other fish, avoid predators, and perhaps to navigate by the Earth's magnetic field. Electroreceptors probably evolved once or twice early in vertebrate evolution, but the sense was apparently lost in amniotes, and in a large number of the Actinopterygii (ray finned fishes) only to reappear independently in two teleost clades. In fish, the ampullary receptor is a specialized receptor that it uses to sense these electric fields and allows the fish to follow electric field lines to their source. Sharks primarily use specialized receptors, called Ampullae of Lorenzini, to detect their prey's low frequency DC fields and may also use their receptors in navigation by the Earth's magnetic field. Weakly electric fish use their ampullary receptors and tuberous receptors to detect the weakly electric fields produced by other fish, as well as for possible predator avoidance. Passive electrolocation contrasts with active electrolocation, in which the animal emits its own weak self generated electric field and detects nearby objects by detecting the distortion of its produced electric field. In active electrolocation the animal senses its own electromotor discharge or reafference instead of some externally generated electric field or discharge.
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Topic Review
Enterprise Modelling
Enterprise modelling is the abstract representation, description and definition of the structure, processes, information and resources of an identifiable business, government body, or other large organization. It deals with the process of understanding an organization and improving its performance through creation and analysis of enterprise models. This includes the modelling of the relevant business domain (usually relatively stable), business processes (usually more volatile), and uses of information technology within the business domain and its processes.
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Topic Review
Imamate (Twelver Doctrine)
Imāmah (Arabic: اٍمامة) means "leadership" and is a concept in Twelver theology. The Twelve Imams are the spiritual and political successors to Muhammad, the Prophet of Islam, in the Twelver branch of Shia Islam. According to Twelver theology, the successors to Muhammad are infallible human beings, who rule justly over the community and maintain and interpret sharia and undertake the esoteric interpretation of the Quran. The words and deeds of Muhammad and the Imams guide the community. For this, the Imams must be free from error and sin and chosen by divine decree—nass—through the Prophet. Shi'a believe that divine wisdom—'Aql—is the source of the souls of the Prophets and Imams and gives them esoteric knowledge—hikmah—and that their suffering is a means by which their devotees may acquire divine grace. The Imam is not the recipient of divine revelation, but has a close relationship with God, who guides him, allowing the Imam in turn to guide others. The Imamat, or belief in the divine guide, is a fundamental belief in Shia Islam and is based on the concept that God would not leave humanity without access to divine guidance. According to the Twelvers, an Imam of the Age is always the divinely appointed authority on all matters of faith and law. Ali was the first Imam in this line and in the view of Twelvers the rightful successor to Muhammad, followed by the male descendants of Muhammad through his daughter Fatimah. Each Imam was the son of the previous Imam, with the exception of Husayn ibn Ali, who was the brother of Hasan ibn Ali. The twelfth and final Imam is Muhammad al-Mahdi, who is believed by the Twelvers to be alive and in hiding.
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Topic Review
Presidential Cabinets of the Weimar Republic
Presidential cabinets (German: Präsidialkabinette) is a term applied to a succession of governments of the Weimar Republic whose legitimacy derived exclusively from presidential emergency decrees. From April 1930 to January 1933, three chancellors, Heinrich Brüning, Franz von Papen, and Kurt von Schleicher, governed without the consent of the Reichstag, Germany's lower house of parliament. Article 48 of the Weimar Constitution gave the President of Germany (Reichspräsident) the power to pass emergency measures which did not require parliamentary support, as long as the federal cabinet approved of them. After a grand coalition led by chancellor Hermann Müller collapsed, president Paul von Hindenburg appointed the Centre Party politician Heinrich Brüning to the chancellorship. Since Brüning did not command a majority in parliament, he governed exclusively through the president's emergency powers. Whenever the government suffered parliamentary defeats, Hindenburg would dissolve the Reichstag and enable Brüning to stay in office. During Brüning's time in office, the fascist National Socialist German Workers' Party and its leader Adolf Hitler became an influential force in German politics. Brüning legislated to oppose the party's paramilitary activity but was replaced with Franz von Papen, a conservative advisor of the president, who sought to compromise with the forces of the radical right. His short-lived presidential government saw the NSDAP gain the largest share of seats in parliament in the election of July 1932. Unable to overcome parliamentary obstruction, he was succeeded by Kurt von Schleicher, who, in turn, gave way to Adolf Hitler on 30 January 1933. The presidential cabinets have been interpreted as a result of scepticism towards parliamentary government in German society as well as a fundamental shift in political practice towards a strong presidential ruler. Hindenburg's decision to govern without the support of the Reichstag constitutes a milestone on Germany's progression from a multi-party democracy to a totalitarian dictatorship under Hitler.
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Topic Review
IBM Spectrum Control
IBM Spectrum Control formerly known as Tivoli Storage Productivity Center (TPC) is a Storage Resource Management (SRM) software offering that provides a centralized point of control for managing large-scale, complex heterogeneous storage environments. IBM Tivoli Storage Productivity Center V5.2.x (5608-PC1) was renamed in V5.2.8 to IBM Spectrum Control Standard Edition V5.2.x (5608-PC1).
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