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Nicos Christofides
Nicos Christofides (born 1942 in Cyprus; died 2019) was a Cypriot mathematician and professor of financial mathematics at Imperial College London. Christofides studied electrical engineering at Imperial College London, where he also received his PhD in 1966 (dissertation: ''The origin of load losses in induction motors with cast aluminum rotors''). He was briefly with Associated Electrical Industries and then again at Imperial College. In 1976, he devised Christofides algorithm, an algorithm for finding approximate solutions to the travelling salesman problem. Christofides algorithm is considered "groundbreaking" and has collected over 2200 citations. In 1982, he became professor of operations research Operations research ( en-GB, operational research) (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a discipline that deals with the development and application of analytical methods to improve dec .... In 1990, he was the co-f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperial College London
Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cultural area that included the Royal Albert Hall, Victoria & Albert Museum, Natural History Museum and royal colleges. In 1907, Imperial College was established by a royal charter, which unified the Royal College of Science, Royal School of Mines, and City and Guilds of London Institute. In 1988, the Imperial College School of Medicine was formed by merging with St Mary's Hospital Medical School. In 2004, Queen Elizabeth II opened the Imperial College Business School. Imperial focuses exclusively on science, technology, medicine, and business. The main campus is located in South Kensington, and there is an innovation campus in White City. Facilities also include teaching hospitals throughout London, and with Imperial College ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Engineering
Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the latter half of the 19th century after commercialization of the electric telegraph, the telephone, and electrical power generation, distribution, and use. Electrical engineering is now divided into a wide range of different fields, including computer engineering, systems engineering, power engineering, telecommunications, radio-frequency engineering, signal processing, instrumentation, photovoltaic cells, electronics, and optics and photonics. Many of these disciplines overlap with other engineering branches, spanning a huge number of specializations including hardware engineering, power electronics, electromagnetics and waves, microwave engineering, nanotechnology, electrochemistry, renewable energies, mechatronics/control, and electrical m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associated Electrical Industries
Associated Electrical Industries (AEI) was a British holding company formed in 1928 through the merger of the British Thomson-Houston Company (BTH) and Metropolitan-Vickers electrical engineering companies. In 1967 AEI was acquired by GEC, to create the UK's largest industrial group. A scandal that followed the acquisition is said to have been instrumental in reforming accounting practices in the UK. Main subsidiaries * Metropolitan-Vickers (Metrovick) * British Thomson-Houston (BTH) * Ferguson, Pailin & Co (switchgear) * Edison Swan (lamps and radio valves) * AEI Lamp and Lighting * Siemens Brothers & Co (cables, telephone equipment and railway signaling apparatus) * Hotpoint (domestic appliances) * Premier Electric Heaters (incorporated into Hotpoint) * W.T. Henley (cables, insulators and low voltage switchgear) * Newton Victor (X-ray machines) * Sunvic Controls (heating controls) * Birlec (industrial electric furnaces) * International Refrigerator Company * Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christofides Algorithm
The Christofides algorithm or Christofides–Serdyukov algorithm is an algorithm for finding approximate solutions to the travelling salesman problem, on instances where the distances form a metric space (they are symmetric and obey the triangle inequality).. It is an approximation algorithm that guarantees that its solutions will be within a factor of 3/2 of the optimal solution length, and is named after Nicos Christofides and Anatoliy I. Serdyukov, who discovered it independently in 1976. This algorithm still stands as the best polynomial time approximation algorithm that has been thoroughly peer-reviewed by the relevant scientific community for the traveling salesman problem on general metric spaces. In July 2020 however, Karlin, Klein, and Gharan released a preprint in which they introduced a novel approximation algorithm and claimed that its approximation ratio is 1.5 − 10−36. Their method follows similar principles to Christofides' algorithm, but uses a rand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Approximation Algorithm
In computer science and operations research, approximation algorithms are efficient algorithms that find approximate solutions to optimization problems (in particular NP-hard problems) with provable guarantees on the distance of the returned solution to the optimal one. Approximation algorithms naturally arise in the field of theoretical computer science as a consequence of the widely believed P ≠ NP conjecture. Under this conjecture, a wide class of optimization problems cannot be solved exactly in polynomial time. The field of approximation algorithms, therefore, tries to understand how closely it is possible to approximate optimal solutions to such problems in polynomial time. In an overwhelming majority of the cases, the guarantee of such algorithms is a multiplicative one expressed as an approximation ratio or approximation factor i.e., the optimal solution is always guaranteed to be within a (predetermined) multiplicative factor of the returned solution. However, there are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Travelling Salesman Problem
The travelling salesman problem (also called the travelling salesperson problem or TSP) asks the following question: "Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the origin city?" It is an NP-hard problem in combinatorial optimization, important in theoretical computer science and operations research. The travelling purchaser problem and the vehicle routing problem are both generalizations of TSP. In the theory of computational complexity, the decision version of the TSP (where given a length ''L'', the task is to decide whether the graph has a tour of at most ''L'') belongs to the class of NP-complete problems. Thus, it is possible that the worst-case running time for any algorithm for the TSP increases superpolynomially (but no more than exponentially) with the number of cities. The problem was first formulated in 1930 and is one of the most intensively studi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operations Research
Operations research ( en-GB, operational research) (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a discipline that deals with the development and application of analytical methods to improve decision-making. It is considered to be a subfield of mathematical sciences. The term management science is occasionally used as a synonym. Employing techniques from other mathematical sciences, such as modeling, statistics, and optimization, operations research arrives at optimal or near-optimal solutions to decision-making problems. Because of its emphasis on practical applications, operations research has overlap with many other disciplines, notably industrial engineering. Operations research is often concerned with determining the extreme values of some real-world objective: the maximum (of profit, performance, or yield) or minimum (of loss, risk, or cost). Originating in military efforts before World War II, its techniques have gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1942 Births
Year 194 ( CXCIV) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Septimius and Septimius (or, less frequently, year 947 ''Ab urbe condita''). The denomination 194 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Emperor Septimius Severus and Decimus Clodius Septimius Albinus Caesar become Roman Consuls. * Battle of Issus: Septimius Severus marches with his army (12 legions) to Cilicia, and defeats Pescennius Niger, Roman governor of Syria. Pescennius retreats to Antioch, and is executed by Severus' troops. * Septimius Severus besieges Byzantium (194–196); the city walls suffer extensive damage. Asia * Battle of Yan Province: Warlords Cao Cao and Lü Bu fight for control over Yan Province; the battle lasts for over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2019 Deaths
This is a list of deaths of notable people, organised by year. New deaths articles are added to their respective month (e.g., Deaths in ) and then linked here. 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 See also * Lists of deaths by day * Deaths by year {{DEFAULTSORT:deaths by year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cypriot Mathematicians
Cypriot (in older sources often "Cypriote") refers to someone or something of, from, or related to the country of Cyprus. * Cypriot people, or of Cypriot descent; this includes: **Armenian Cypriots **Greek Cypriots **Maronite Cypriots **Turkish Cypriots * Cypriot dialect (other), the dialects being spoken by Cypriots * Cypriot syllabary, the ancient syllabic writing system of Cyprus, in use 1100–300 BCE * Cypriot cuisine Cypriot cuisine is mainly influenced by Greek and Turkish cuisines, whilst also sharing similarities with the cuisines of Italy and France. Food preparation Frequently used ingredients are fresh vegetables such as zucchini, olives, okra, gre ... {{disambiguation Language and nationality disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
