unreferenced date May 2010 The AdvancedComputationGroup ACG is a group within Apple Inc . The ACG researches algorithms and high performance issues relevant to Apple technology. ACG concentrates on Mac OS X for computer science Relationship with other fields scientific applications , vectorization parallel computing vectorization , tutorials, algorithm implementations for specific Apple products and joint research and development with outside partners. One particularly high profile project of the ACG is Apple Genentech BLAST an algorithm for comparing biological sequences, such as the amino acid sequences of different proteins which runs several times faster on Power Mac and Xserve than generic BLAST runs on other platforms. This implementation is open source software developed in cooperation with Genentech . The ACG also developed Apple s Xgrid , which is cluster computing cluster ing and distributed computing software for Macintosh computers, allowing central processing unit processor intensive applications to borrow processing power from other computers on their network. Much of the work of the ACG has been directed toward advanced uses of PowerPC processors which have run Macintosh computers since the 1990s. Now that Apple has completed their Apple Intel transition transition to Intel processors , the ACG s work is increasingly focused on that new platform. External links http www.apple.com acg ACG web site http www.apple.com acg archive.html ACG archive primarily concerned with PPC architecture, but much is also applicable to Intel architecture http developer.apple.com opensource tools blast.html A G BLAST Apple Category Apple Inc. Category Cluster computing ... more details
in Need and spinal research. Advanced Riding Skills Much of the observed rider training follows ... here automatically Reflist External links http www.kamg.org.uk Kent Advanced Motorcyclists Group web site http www.iam.org.uk do you want to be a better rider doyouwanttobeabetterrider.html ... more details
The Advanced Programming Group APSG is a Specialist Group SG of the British Computer Society BCS . It held its first meeting, when it was referred to as BCS Study Group No. 5 , at Bishop s House, High Holborn , London WC1, England on 17 December 1959. It has met continuously in London since then, generally on the second Thursday of the months from October to May each year. Its purpose is to disseminate information on emerging concepts, programming languages, tools and techniques. Rather than relying on publication, the main format for communication is a talk from an invited speaker whose slides are made available on the Group s website http www.bcs.org groups advprog . Past chairmen of the Group were Ewart Willey first chairman 1959 1974 , Peter King 1974 1980 , Peter Prowse 1980 1982 and John Florentin 1982 2010 . The current chairman is Prof. Geoff Sharman 2011 . From time to time, the Group holds joint meetings with other BCS SGs, for example May 2010, with Fortran SG, Parallel Programming in Fortran with Coarrays January 2010 with Computer Conservation Society , The 50th Anniversary of the publication of the Algol 60 Report October 2006, with Computer Conservation Society , The first 35 years of IBM Hursley software November 2005, with Formal Aspects SG BCS FACS , Separation Logic The Group has had several recent talks focusing on each of the following topic areas Aspect oriented programming and Aspect oriented Design AOSD Enterprise Level Software Architecture Enterprise software and most recently Parallel programming for multi core systems External links http www.bcs.org groups advprog Advanced Programming Group website Category 1959 establishments Category Software engineering organizations Category BCS Specialist Groups ... more details
Refimprove date May 2010 Use mdy dates date August 2010 The Advanced Technology Group ATG was a corporate research laboratory at Apple Inc. Apple Computer from 1986 to 1997. ATG was started by Larry Tesler in October 1986 to study long term research into future technologies that were beyond the time frame or organizational scope of any individual product group. Over the next decade it was led by David Nagel , Richard LeFaivre , and Donald Norman . It was known as Apple Research Labs during Norman s tenure as VP of the organization. Steve Jobs closed the group when he returned to Apple in 1997. ref Cite web last Davis first Jim title Apple shutters Advanced Technology Group publisher cnet.com date 1997 10 07 url http news.cnet.com 2100 1001 203996.html ref ATG had research efforts in both hardware and software, with groups focused on such areas as Human Computer Interaction, Speech Recognition, Educational Technology, Networking, Information Access, and Language action perspective . Many of these efforts are described in a special issue of the ACM SIGCHI bulletin which provided a retrospective of the ATG work after the lab was shut down. ATG was also home to two Apple Fellows, object oriented software pioneer Alan Kay and laser printer inventor Gary Starkweather . Further, ATG funded university research and, starting in 1992, held an annual design competition for teams of students. Apple s ATG was the birthplace of Color QuickDraw , QuickTime , QuickTime VR , QuickDraw 3D , 3DMF the 3D metafile graphics format, ColorSync , HyperCard , Apple events , AppleScript , Apple s PlainTalk speech recognition software, Apple Data Detectors , the V Twin software for indexing, storing, and searching text documents, Macintalk Pro Speech synthesis Speech Synthesis , the Apple Newton OS Newton Handwriting recognition handwriting recognizer , the component software technology leading to OpenDoc ... miller1.html SIGCHI The Apple Advanced Technology Group http vpwpartners.blogs.com viewpoint west partners ... more details
Multiple issues advert October 2009 refimprove October 2009 Advanced Microscopy Group or AMG is a manufacturer of microscopes based in Mill Creek, Washington . ref http www.amgmicro.com Advanced Microscopy Group ref Their products include the EVOS Microscope, a digital inverted microscope for use in fluorescence and Transmittance transmitted light applications. ref http www.photonics.com Content ReadArticle.aspx?ArticleID 29924 Evos Inverted Microscope June 12, 2007 Photonics.com ref It utilizes a Light emitting diode LED illumination system. The integrated microprocessor and imaging system, and a high resolution digital camera let users process and analyze live and captured images. The 15 inch Liquid crystal display LCD display replaces the traditional eye pieces. Software features include time lapse, cell counting and transfection analysis. A key feature of the EVOS fluorescence microscope is its LED based light cube system. Each light cube integrates the illumination source, the light engine and the fluorescence filters into a single unit, removing need for alignment or calibration. The optical path is shortened and the light cube delivers bright illumination intensities. Each LED lasts for more than 50,000 hours. LEDs can be adjusted and controlled, and the chance of photobleaching or phototoxicity is reduced. The embedded microprocessor gives users control of image acquisition and management. Mouse controlled user interface allows adjusting illumination levels, balancing fluorescence and transmitted light channels, and capturing image data and saving it to a portable USB flash drive . This portable unit can be placed in a cell culture hood for sensitive cell isolation procedures and is equipped with a Digital Visual Interface DVI output that can be connected to an external display or monitor. gallery Image Evos fl microscope.jpg EVOS Fluorescence Microscope gallery References reflist Optical microscopy Category Microscopy Category Luminescence Category Fluorescence ... more details
Original research date June 2010 The Advanced Research and Assessment Group ARAG was a department of the Defence Academy of the United Kingdom concerned with long term planning and threat assessment. ARAG was established in 2005 by Chris Donnelly CMG, the former principal advisor to NATO Sec. Gen. He realised that across the UK MoD Clarify date June 2010 and wider government no organisation was either adaptable or innovative enough to research 21st Century security challenges. ARAG brought together experts from the military, academia and other fields in research clusters dedicated to specific areas of concern, in order to provide policy makers with focussed analysis of international security issues. ARAG members were hand picked and came from a wide background of skills, experience and nationalities. ARAG subsumed the Conflict Studies Research Centre , previously known as the Soviet Studies Research Centre, which for nearly 40 years had studied the Soviet Union, working in open source organic languages to supplement MoD and Intelligence Service assets. ARAG worked across government departments undertaking both directed and undirected research and broadening its reach to encompass new security challenges such as China, cyber security and Strategic Communication. It produced a large number of research papers made freely available to the public from the Defence Academy website as well as more targeted limited distribution work. Many of these papers became seminal reference works including A Reassessment by Dr James Sherr, Charles Blandy s correct prediction of the Russian attack on Georgia, Professor James Pettifer s analysis of the Greek financial crisis and the joint paper by Major General Andrew Mackay British Army officer Andrew Mackay and Commander Steve Tatham. Mackay ... http www.da.mod.uk colleges arag Advanced Research and Assessment Group http www.conflictstudies.org.uk ... Conflict Studies Research Centre is a research, analysis and consultancy group with strong expertise ... more details
Refimprove date May 2011 Computation is defined as any type of calculation . ref http www.merriam webster.com dictionary computation ref Also defined as use of computer technology in Information processing . ref http dictionary.reference.com browse computation ref ref http www.answers.com topic computation ref Computation is a process following a well defined Model abstract model understood and expressed in an algorithm , Protocol computing protocol , network topology , etc. Computation is also a major subject matter of computer science it investigates what can or cannot be done in a computational manner. Wiktionary computation Classes of computationComputation can be classified by at least three orthogonal criteria digital vs analog electronics analog , sequential vs parallel computation parallel vs Concurrency computer science concurrent , batch processing batch vs interactive computation interactive . In practice, digital computation is often used to simulate natural processes for example, Evolutionary computation , including those that are more naturally described by analog models of computation for example, Artificial neural network . Computations as a physical phenomenon A computation can be seen as a purely physical phenomenon occurring inside a closed physical system called ... of view is the one adopted by the branch of theoretical physics called the physics of computation ... of the universe itself is a computation Pancomputationalism . Mathematical models of computation In the theory of computation , a diversity of mathematical models of computers have been developed. Typical mathematical Model of computation models of computers are the following State models including ... and process calculi History The word computation has an archaic meaning from its Latin language Latin ... computer science. Comparison to calculation See Calculation Comparison to computation See also Portal Computer Science Computing Physical information Real computation Reversible computation Hypercomputation ... more details
Infobox Laboratory name Advanced Numerical Research & Analysis Group motto logo image established 2 May 1988 city Hyderabad, Andhra Pradesh Hyderabad , Andhra Pradesh AP research field type director C V S Sastry staff budget operating agency DRDO affiliations address Kanchanbagh, br Hyderabad 500 058 telephone campus website http www.drdo.org labs electronics anurag index.shtml ANURAG Home Page footnotes DRDO Laboratories Advanced NUmerical Research and Analysis Group ANURAG is a laboratory of the Defence Research and Development Organisation DRDO . Located in Kanchanbagh, Hyderabad, Andhra Pradesh Hyderabad , it is involved in the development of computing solutions for numerical analysis and their use in other DRDO projects. History ANURAG was established on May 2, 1988, to support aeronautical design work, ref name GlobalSecurity http www.globalsecurity.org wmd world india hyderabad drc other.htm anurag Defence Research Complex, Kanchanbagh, Hyderabad , GlobalSecurity.org report on ANURAG. ref with the mandate of executing specific, time bound projects leading to the development of custom designed computing systems and software packages for numerical analysis and other applications. ref http drdo.org labs electronics anurag history.shtml ANURAG home page Historical background ref Areas of work ANURAG helps design and develop advanced computing systems. Much of this research is conducted in state of the art concepts like parallel architectures, etc., in order to build up a technology base in these areas. Its areas of work are ref http drdo.org labs electronics anurag areas.shtml ANURAG Home Page Areas of work ref Parallel processing technology. System engineering, integration. General purpose microprocessors. 1 micrometre CMOS fabrication technology. Design and development of VLSI chips & SOC development. Processor related technology. System software development for custom .... coord missing Andhra Pradesh DEFAULTSORT Advanced Numerical Research And Analysis Group Category ... more details
Reverse computation is a computer software software application of the concept of reversible computing ... cite journal last Bennett first Charles H. coauthors year 1982 title The thermodynamics of computation ... computation is somewhat simpler than reversible computing in that reverse computation is only required ... as reverse computation in software application areas such as database design, ref cite journal ... Institute National de Recherche en Informatique et en Automatique INRIA accessdate ref Reverse Computation ... computable and their costs. Based on the successful application of Reverse Computation ... 1999 title Efficient optimistic parallel simulations using reverse computation url http www.cs.uga.edu ... for Computing Machinery accessdate 2009 04 06 ref suggest the application of reverse computation ... amount of computation per event . The key property that reverse computation exploits is that a majority ... makes this operation reversible. History of Reverse Computation as applied to Parallel Discrete ... Computation has only been applied in software for optimistically synchronized, parallel discrete ... doctoral thesis focused on reverse computation at the hardware level, but included descriptions of both ... on reverse computation. ref cite journal last Vieri first C. coauthors Ammer, M.J. Frank, M. Norman ... Workshop volume issue pages 138 142 doi pmid publisher accessdate ref ref group notes ... reverse computation to 2004 and http www.eng.fsu.edu mpf pubs.htm later . ref In 1998 Carothers and Perumalla published a paper for the Principles of Advanced and Distributed Simulation workshop ..., introducing technique of Reverse Computation as an alternative rollback mechanism in optimistically ... System ROSS , which supported only reverse computation as the rollback mechanism. Carothers ... reverse computation. From 1998 to 2005 Bauer performed graduate work at RPI under Carothers, focusing solely on reverse computation. He developed the first PDES system solely based on reverse computation ... more details
The study of the physics of computation relates to understanding the fundamental physical limits of computer s. This field has led to the investigation of how thermodynamics limits information processing, the understanding of Chaos theory chaos and dynamical systems , and a rapidly growing effort to invent new quantum computer s. See also list of publications in physics Physics of computation important publications in physics of computation See also Digital physics Computation Theory of computation Reversible computation Hypercomputation Physical information Limits to computation Bremermann s limit References Lloyd, S., 2000, Ultimate physical limits of computation, Nature journal Nature , 406 1047 1054. Category Computational physics physics stub ... more details
Indeterminancy in computation may refer to Quantum indeterminacy in quantum computer s Nondeterministic finite automata Nondeterministic algorithm In concurrency Indeterminacy in concurrent computation Unbounded nondeterminism disambig ... more details
Morphological computation may refer to Morphological computation robotics Computational linguistics disambig Long comment to avoid being listed on short pages ... more details
Computation CEC Genetic and Evolutionary Computation Conference GECCO ref name SIGEVO cite web title Special Interest Group on Genetic and Evolutionary Computation url http www.sigevo.org publisher ...for the journal Evolutionary Computation journal In computer science , evolutionary computation is a subfield of artificial intelligence more particularly computational intelligence that involves combinatorial optimization problems. Evolutionary computation uses iterative progress, such as growth or development in a population . This population is then artificial selection selected in a guided random search using parallel processing to achieve the desired end. Such processes are often inspired by biological mechanisms of evolution . As evolution can produce highly optimised processes and networks, it has many applications in computer science . Here, simulations of evolution using evolutionary ..., evolutionary computation has largely become swarm based computation, and nature inspired algorithms ... algorithms Main Evolutionary algorithm Evolutionary algorithms form a subset of evolutionary computation ... a chance to become a parent or to survive. Evolutionary computation practitioners Kalyanmoy Deb David ... computation Inferential programming Interactive evolutionary computation Mutation testing No free lunch ... Jong, Evolutionary computation a unified approach. MIT Press , Cambridge MA, 2006 A. E. Eiben and J.E. .... Genetic Programming An Introduction. Morgan Kaufmann, 1998. D. B. Fogel. Evolutionary Computation ... Computation, 1 1 1 23, 1993. J. R. Koza. Genetic Programming On the Programming of Computers by means ... Evolutionary Computation Repository http www.cse.dmu.ac.uk rij gafaq top.htm Hitch Hiker s Guide to Evolutionary Computation FAQ for comp.ai.genetic http userweb.eng.gla.ac.uk yun.li ga demo Interactive illustration of Evolutionary Computation http www.vita sciences.org VitaSCIENCES DEFAULTSORT Evolutionary Computation Category Evolutionary computation ca Computaci evolutiva es Computaci n evolutiva ... more details
Unreferenced date December 2009 A computation tree is a representation for the computation steps of a non deterministic Turing machine on a specified input. A computation tree graph theory tree is a rooted tree of nodes and edges. Each node in the tree represents a single computational state, while each edge represents a transition to the next possible computation. The number of nodes of the tree is the size of the tree and the length of the path from the root to a given node is the depth of the node. The largest depth of an output node is the depth of the tree. The output nodes of the tree are called leaves. In a computation tree each output node is labeled Yes or No. If a tree, T, with an input space X, if math x in X math and the path for x ends in node labeled yes, then the input x is accepted. Else it is rejected. The depth of the computation tree for a given input is the computation time for the Turing machine on that input. One of the primary methods of showing that a computational problem L is complete complexity complete for a given complexity class C is to show that the computation tree of any algorithm in C can be directly analyzed in terms of L . DEFAULTSORT Computation Tree Category Computational complexity theory ... more details
In computer science , interactive computation is a mathematical model for computation that involves communication with the external world during the computation. This is in contrast to the traditional understanding of computation which assumes a simple interface between a computing agent and its environment, consisting in asking a question input and generating an answer output . The famous Church Turing thesis attempts to define computation and computability in terms of Turing machines . However the Turing machine model only provides an answer to the question of what computability of functions means and, with interactive tasks not always being reducible to functions, it fails to capture our broader intuition of computation and computability. While this fact was admitted by Alan Turing himself, it was not until recently that the theoretical computer science community realized the necessity to define adequate mathematical models of interactive computation. Among the currently studied mathematical models of computation that attempt to capture interaction are http www.csc.villanova.edu japaridz Japaridze s hard and easy play machines elaborated within the framework of computability logic , http www.cse.uconn.edu dqg Goldin s persistent Turing machines, and http research.microsoft.com gurevich Gurevich s abstract state machines. Peter Wegner has additionally done a great deal of work on this area of computer science. See also Human based computation Computability logic Game semantics Interactive programming Quasi empiricism in mathematics Quasi empiricism References and external web sources Interactive Computation The New Paradigm ISBN 354034666X. Edited by D.Goldin, S.Smolka and P.Wegner. ... dqg D.Q.Goldin , Persistent Turing Machines as a model of interactive computation . Lecture Notes ... Machines, Transition Systems, and Interaction . J. Information and Computation 194 2 2004 , pp. ... . Theoretical Computer Science 192 1998 , pp. 315 351. Category Theory of computation Category ... more details
Italic title Mathematics of Computation ref http www.ams.org mcom aboutmcom.html Mathematics of Computation Journal overview , retrieved April 2007 ref is a quarterly mathematics journal focused on computational mathematics that is published by the American Mathematical Society . It was established in 1943. The articles in all volumes older than five years are available electronically free of charge. ref http www.ams.org jourcgi jrnl toolbar nav mcom all Mathematics of Computation Archive ref References reflist Category Mathematics journals Category Quarterly journals sci journal stub ... more details
of computation that is more restricted than the set of operations that you could use in practice and therefore ... Models of Computation An Introduction to Computability Theory publisher Springer year 2009 series Undergraduate Topics in Computer Science isbn 978 1 84882 433 1 DEFAULTSORT Model Of Computation Category Models of computation Category Theory of computation Comp sci stub bg es Modelo ... more details
Pulse computation is a hybrid of digital computer digital and analog computer analog computation that uses aperiodic electrical spikes, as opposed to the Periodic function periodic voltages in a digital computer or the continuously varying voltages in on analog computer. Pulse streams are unlocked, so they can arrive at arbitrary times and can be generated by analog processes, although each spike is allocated a binary value, as it would be in a digital computer. ref citation first1 Jeffrey last1 Miller first2 Woodward last2 Young title Simple Pulse Asynchronous State Machines url http vlsi.eecs.harvard.edu techreports iscas96m.ps accessdate 2009 08 25 ref Pulse computation is primarily studied as part of the field of neural network s. The processing unit in such a network is called a neuron . References reflist Category Computational neuroscience comp sci stub ... more details
italictitle Infobox Journal title Neural Computation cover Image neuralcomputationlowres.jpg editor Terrence J. Sejnowski discipline Neuroscience language English abbreviation Neural Comput. publisher MIT Press country United States frequency Monthly history 1989 present openaccess impact 2.175 impact year 2009 website http www.mitpressjournals.org loi neco link1 http www.mitpressjournals.org toc neco current link1 name Online access link2 link2 name RSS atom JSTOR OCLC 39265996 LCCN CODEN ISSN 0899 7667 eISSN 1530 888X Neural Computation is a peer reviewed academic journal covering aspects of neural computation . Articles highlight problems and techniques in modeling the brain, and in the design and construction of neurally inspired information processing systems. Neural Computation was founded in 1989 and is published online and in hard copy by the MIT Press . External links http www.mitpressjournals.org loi neco Official website sci journal stub Portal Neuroscience Category Neuroscience journals Category MIT Press academic journals Category Monthly journals Category English language journals Category Publications established in 1989 Category Academic journal stubs ... more details
about accurate manipulation of mathematical expressions simultaneous exploration of the many paths computer execution can take symbolic execution Symbolic computation or algebraic computation or computer algebra relates to algorithm s and software for manipulating mathematics mathematical expression mathematics expressions and equation s in symbol symbolic form, as opposed to manipulating the approximations of specific numerical analysis numerical quantities represented by those symbols. Software applications that perform symbolic calculations are called computer algebra system s . These systems might be used for symbolic symbolic integration integration or derivative differentiation , substitution of one expression into another, simplification of an expression, etc., for most operations of calculus and, more generally, for every computation with mathematical objects for which algorithms are known. Computer algebra softwares are widely used in many scientific and engineering domains. Symbolic computation is also sometimes referred to as symbolic manipulation , symbolic processing , symbolic mathematics , or symbolic algebra , but these terms also refer to non computational manipulation. See also Automated theorem prover Computer assisted proof Proof checker Model checker Symbolic numeric computation Symbolic simulation Symbolic execution References reflist http www.risc.jku.at about editorial editorial.pdf Symbolic Computation An Editorial , Bruno Buchberger, Journal of Symbolic Computation 1985 1, pp. 1 6. http www.csd.uwo.ca watt pub reprints 2006 tc sympoly.pdf Making Computer Algebra More Symbolic Invited , Stephen M. Watt, pp. 43 49, Proc. Transgressive Computing 2006 A conference in honor or Jean Della Dora , TC 2006 , April 24 26 2006, Granada Spain. External links http www.cs.mu.oz.au schachte lpanalysis.html A Gentle Introduction to Static Analysis and Logic Programming showing an example of application of symbolic computation to perform static program anal ... more details
In computability theory , the theory of real computation deals with hypothetical computing machines using infinite precision real number s. They are given this name because they operate on the set of real number s. Within this theory, it is possible to prove interesting statements such as the complement of the Mandelbrot set is only partially decidable . These hypothetical computing machines can be viewed as idealised analog computer s which operate on real numbers, whereas digital computer s are limited to computable numbers. They may be further subdivided into differential mathematics differential and algebraic models digital computers, in this context, should be thought of as topology topological , at least insofar as their operation on computable real s is concerned ref cite book title A Simple Introduction to Computable Analysis author Klaus Weihrauch year 1995 url http eccc.uni trier.de static books A Simple Introduction to Computable Analysis Fragments of a Book ref . Depending on the model chosen, this may enable real computers to solve problems that are inextricable on digital computers for example, Hava Siegelmann s neural nets can have noncomputable real weights, making them able to compute nonrecursive languages , or vice versa Claude Shannon s idealized analog computer can only solve algebraic differential equations, while a digital computer can solve some transcendental ... analog computer computations are immediately done, i.e. computation is done in real time. Shannon ... 317 335 month Jun year 2007 doi 10.1016 j.jco.2006.12.005 ref A canonical model of computation over the reals is Blum Shub Smale machine BSS . If real computation were physically realizable, one could ... Smale title Complexity and Real Computation isbn 0387982817 cite book last Campagnolo first Manuel ... first Hava title Neural Networks and Analog Computation Beyond the Turing Limit isbn 0 8176 ... of computation Category Hypercomputation Comp sci stub ... more details
Citations missing date September 2007 In theoretical computer science , the theory of computation is the branch that deals with whether and how efficiently problems can be solved on a model of computation ... of computation, computer scientists work with a mathematical abstraction of computers called a model of computation. There are several models in use, but the most commonly examined is the Turing machine ... reasonable model of computation. Citation needed date September 2010 It might seem that the potentially ... of computation The theory of computation can be considered the creation of models of all kinds in the field ... of computation were Alonzo Church , Alan Turing , Stephen Kleene , John von Neumann , Claude Shannon ... of studying only models of computation which are reducible to the Turing model. Many mathematicians ... and space complexity, which are respectively how many steps does it take to perform a computation, and how much memory is required to perform that computation. In order to analyze how much time and space ... classes P and NP . Models of computation This section is linked from Abstract machine main Model of computation Aside from a Turing machine , other equivalent See Church Turing thesis models of computation are in use. Lambda calculus A computation consists of an initial lambda expression or two ... their role in mathematics . mu recursive function s a computation consists of a mu recursive ... x math , then for f 5 3 to appear, terms like g 5 6 and h 5,6 3 must occur above. The computation terminates ... models of computation have the ability to do different tasks. One way to measure the power of a computational ..., Languages, and Computation . 3rd ed Reading, MA Addison Wesley. ISBN 978 0321455369 One of the standard ... of Computation 2ed publisher PWS Publishing isbn 0534950973 cite book author Eitan Gurari year 1989 title An Introduction to the Theory of Computation url http www.cse.ohio state.edu gurari theory ... of Computation. Sudbury, MA Jones & Bartlett. ISBN 978 0867204971 A gentle introduction to the field ... more details
unreferenced date October 2006 In computer science , a computation history is a sequence of steps taken by an abstract machine in the process of computing its result. Computation histories are frequently used in Mathematical proof proofs about the capabilities of certain machines, and particularly about the undecidability of various formal languages . Formally, a computation history is a normally Finite set finite sequence of configurations of a formal automaton . Each configuration fully describes the status of the machine at a particular point. To be valid, certain conditions must hold the first configuration must be a valid initial configuration of the automaton and each transition between adjacent configurations must be valid according to the transition rules of the automaton. In addition, to be complete , a computation history must be finite and the final configuration must be a valid terminal configuration of the automaton. The definitions of valid initial configuration , valid transition ... automaton has exactly one computation history for a given initial configuration, though the history ... state is an accepting state. Turing Machines Computation histories are more commonly used in reference ... results Computation histories can be used to show that certain problems for pushdown automata are undecidable . This is because the language of non accepting computation histories of a Turing ... pushdown automaton. We encode a Turing computation history math c 0,c 1,...,c n math as the string ..., and reject if not. This same trick cannot be used to recognize accepting computation histories with an NPDA ... bounded Turing machine is sufficient to recognize accepting computation histories. This result allows ... math w math , we can form the pushdown automaton math P math which accepts non accepting computation ... computation histories for math M math on math w math this would allow us to decide math A TM math , which we know to be undecidable. Category Theory of computation pt Hist rico de computa o ... more details
There are several physical and practical limits to the amount of computation or data storage device data storage that can be performed with a given amount of mass, volume, or energy The Bekenstein bound limits the amount of information that can be stored within a spherical volume to the entropy of a black hole with the same surface area. The temperature of the cosmic microwave background radiation gives a practical lower limit to the energy consumed to perform computation of approximately 4 kT per state change, where T is the temperature of the background about 3 kelvin s , and k is the Boltzmann constant . While a device could be cooled to operate below this temperature, the energy expended by the cooling would offset the benefit of the lower operating temperature . Bremermann s limit is the maximum computational speed of a self contained system in the material universe, and is based on mass energy versus quantum uncertainty constraints. Several methods have been proposed for producing computing devices or data storage devices that approach physical and practical limits A cold degenerate star could conceivably be used as a giant data storage device, by carefully perturbing it to various excited states, in the same manner as an atom or quantum well used for these purposes. Such a star would have to be artificially constructed, as no natural degenerate stars will cool to this temperature for an extremely long time. It is also possible that nucleon s on the surface of neutron star s could form complex molecules ref cite encyclopedia year title Life on neutron stars encyclopedia ... and Computation date 20041025030505 ref creating a type of computronium based on femtotechnology ... this hypothetical computation is performed at ultra high densities and speeds, the total number ... 2000 month title Ultimate physical limits to computation journal Nature journal Nature volume 406 ... problem References Reflist Category Theory of computation pt Limites da computa o ... more details
Multiple issues notable June 2011 refimprove June 2011 italictitle Decimal Computation is a textbook by Hermann Schmid. First published in 1974 by John Wiley & Sons ISBN 047176180X and reprinted in 1983 by Robert E. Krieger Publishing Company ISBN 0898743184 , the book comprises twelve chapters providing detailed description of decimal calculations, including explanation of binary coded decimal s and algorithm s. ref cite journal title Electronic Design url http books.google.com books?id 90EAQAAIAAJ year 1974 publisher Hayden Pub. Co. volume 22 issue 19 22 oclc 1567748 page 161 ref References Reflist Category 1974 books compu book stub ... more details
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