model. There are many models of computation, differing in the set of admissible operations and their computations ...Refimprove date December 2009 For computer models simulating complex systems Computational model In model driven engineering , the model of computation explains how the behaviour of the whole system is the result of the behaviour of each of its components. In computability theory computer science computability theory and computational complexity theory , a model of computation is the definition of the set of allowable operations used in computation and their respective costs. It is used for measuring the complexity of an algorithm in Run time program lifecycle phase execution time and or memory space by assuming a certain model of computation, it is possible to analyze the computational resources required or to discuss the limitations of algorithms or computers. Some examples of models include Turing machines , Recursion computer science recursive functions , lambda calculus , and production systems . In the field of runtime analysis of algorithms , it is common to specify a computational model in terms of primitive operations allowed which have unit cost, or simply unit cost operations . A commonly used example is the random access machine , which has unit cost for read and write access ... of computability and upper bounds on computational complexity of algorithms, and decision tree model ... which is often overlooked is that published lower bounds for problems are often given for a model 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 de computaci n hr Model ra unanja pt Modelo de computa o ru ... more details
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 ...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 ... of view is the one adopted by the branch of theoretical physics called the physics of computation ... lambda calculus Logical models including logic programming Concurrent models including actor model 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
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
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
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 ...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 ... analog computer computations are immediately done, i.e. computation is done in real time. Shannon s model can be adapted to cope with this problem . ref cite journal author O. Bournez, M. L. Campagnolo ... 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
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
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 ..., evolutionary computation has largely become swarm based computation, and nature inspired algorithms ... Evolution Model Parallel simulated annealing Self organization such as self organizing map s, competitive ... 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 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 ... 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
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 studying only models of computation which are reducible to the Turing model. Many mathematicians ... 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 ... 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 ... 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 ... 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 model is to study the class of formal language s that the model can generate in such a way ..., 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 ... 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 ... reverse computation to 2004 and http www.eng.fsu.edu mpf pubs.htm later . ref In 1998 Carothers ..., introducing technique of Reverse Computation as an alternative rollback mechanism in optimistically ... System ROSS , which supported only reverse computation as the rollback mechanism. Carothers ... them during execution in response to model dynamics. In 2007 Perumalla tested uSik on Blue ... 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 ... model . ref cite journal last Bauer Jr. first David W. coauthors Page, Ernest H. year 2007 title ... 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
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
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
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
Primary sources date January 2010 italictitle Infobox journal title Information and Computation cover File Journalcover Ic.gif editor Albert R. Meyer discipline Computer Science peer reviewed language abbreviation publisher Academic Press country United States USA frequency monthly history 1957 present formerly named Information and Control openaccess license impact 1.504 impact year 2008 website http www.elsevier.com wps find journaldescription.cws home 622844 description description link1 http www.sciencedirect.com science journal 08905401 link1 name online access link2 http projects.csail.mit.edu iandc link2 name Journal homepage at Massachusetts Institute of Technology MIT RSS http rss.sciencedirect.com publication science 6825 atom JSTOR OCLC LCCN CODEN ISSN 0890 5401 eISSN boxwidth Information and Computation is a computer science scientific journal journal published by Elsevier Academic Press . The journal was founded in 1957 under its former name Information and Control . The editor in chief is A.R. Meyer Lab. for Computer Science, Massachusetts Institute of Technology, Cambridge, USA . This particular journal publishes 12 issues a year. All articles from the Information and Computation journal can be viewed on indexing services like Scopus and Science Citation Index . The 2008 Impact Factor for this journal is 1.504 and the 5 Year Impact Factor is 1.600 Journal Citiation Reports 2009, Published by Thomson Reuters . Category Computer science journals Category Elsevier academic journals Category Publications established in 1957 sci journal stub ... more details
suppose that the computation math phi X z math converges in math s math steps and only looks at the first ... math X s z X z math . If math t s math then the computation math phi X t z math converges in at most .... Category Computability theory Category Theory of computation ... more details
refimprove date February 2008 Computation of a cyclic redundancy check is derived from the mathematics of Mathematics of CRC polynomial division, modulo two . In practice, it resembles long division of the Binary code binary message string, with a fixed number of zeroes appended, by the generator polynomial string except that exclusive OR operations replace subtractions. Division of this type is efficiently realised in hardware by a modified shift register , and in software by a series of equivalent algorithm s, starting with simple code close to the mathematics and becoming faster and arguably more obfuscated code obfuscated ref name williams93 cite web url http www.repairfaq.org filipg LINK F crc v3.html title A Painless Guide to CRC Error Detection Algorithms V3.00 accessdate 2008 02 07 last Williams first Ross N. date 1996 09 24 ref through byte wise parallelism and space time tradeoff s. Image CRC8 gen.gif thumb right 380 px Example of generating an 8 bit Cyclic redundancy check CRC . The generator is a Galois type LFSR shift register with xor xor gates placed according to powers white numbers of x in the generator polynomial. The message stream may be any length. After it has been shifted through the register, followed by 8 zeroes, the result in the register is the checksum. Image CRC8 rx.gif thumb 380 px Checking received data with checksum. The received message is shifted through the same register as used in the generator, but the received checksum is attached to it instead ... of the CRC in the order that matches your chosen bit ordering convention. Parallel computation ... the bit at a time code. Parallel computation without table Parallel update for a byte or a word at a time ... 4 p p p 2 p p p 1 p p & 1 f e p 8 r c 8 f 6 f 7 f 8 Two step computation As the CRC 32 polynomial has ... input or cascaded XOR gates which increases propagation delay . To maximise computation speed ... name glaise cite journal last Glaise first Ren J. authorlink date 1997 01 20 title A two step computation ... more details
Model A may refer to Ford Model A 1927 1931 , a model of car built by the Ford Motor Company Ford Model A 1903 1904 , a model of car built by the Ford Motor Company One of the letter series models of Farmall tractors One of the letter series models of John Deere tractors by Deere & Company A structural model of personality in Socionics see Socionics Model A Socionics Model A Model A band , an art rock band from California A character mode in the video game Mega Man ZX Advent Ritz Model A , ultralight aircraft disambig ... more details
TOC right Wiktionary modelModel may refer to Physical Physical model , a physical representation of an object Scale model , a replica or prototype of an object 3D modelling , a 3D polygonal representation of an object, usually displayed with a computer Model aircraft Car modelModel building , a hobby ... of the solid parts of an object, also called in vitro models Model organism , a simple organism used as model in biology Model product , an identifier of a product given by its manufacturer also called model number . Human models Model art , a person who poses to be depicted in art, for example in art school Model person , a person employed to display his or her looks or something such as a commercial product Fetish model , a model who wears the clothing and or devices of sexual fetishes Promotional model , a person who interacts with consumers to draw attention to and often inform them about a product Pseudo model , lang mo u a term coined in Hong Kong for young would be models Role model , a person who serves as a behavioural or moral example to others Nonphysical Abstract Conceptual model , a nonphysical model Interpretation logic , a model is part of an interpretation of facts in logic, a mapping of truth values to sentences. Mathematical model , an abstract model that uses mathematical language Structure mathematical logic , in model theory often called just a model or semantic model Applied Business model , a framework of the business logic of a firm Causal model , an abstract model that uses cause and effect logic Computer model , a computer program which attempts to simulate an abstract model of a particular system Molecular model , a physicochemical or mathematical description that models the behaviour of molecules Data model , a description of database structure Economic model , a theoretical construct representing economic processes Ecosystem model , a representation of components and flows through an ecosystem Graphical model , a probabilistic model for which ... more details
The T Model is a formula that states the returns earned by holders of a company s stock in terms of accounting ... the period book value The T Model connects fundamentals with investment return, allowing an analyst ... in, the T Model gives a close approximation of actually realized stock returns ref Estep, Tony, Security ..., it has the advantage of being correct in a mathematical sense see T Model Derivation derivation ... and Richard Lynn, Is The Estep T Model Consistently Useful? Financial Analysts Journal, November ... techniques such as price earnings or the simplified dividend discount model it is mathematically ... Estep published a T Model The Cash Flow T Model version of the T Model driven by cash items cash ... models such as the Capital Asset Pricing Model and its various descendants financial models attempt ... PB PB mathit 1 g math Substituting 3 and 4 into 2 gives 1 , the T Model. The Cash Flow T Model In 2003 Estep published a version of the T Model that does not rely on estimates of Return on Equity, but rather ... from the balance sheet. The Cash flow T Model is math mathit T frac mathit CF mathit P boldsymbol ..., and Investment Returns , The Journal Of Portfolio Management, Spring 2003 ref that this model is mathematically identical to the original T Model, and gives identical results under certain simplifying ... it may be preferable to the standard T Model, because the specific accounting items used as input values ... valuation formulas and techniques can be understood as simplified cases of the T Model. For example ... period. The third term of the T Model becomes zero, and the remaining terms simplify to math ... Gordon yield plus growth model. It will be a correct estimate of T if PB does not change ... and the required return, T . The T Model is also closely related to the P B ROE model of Wilcox ref Wilcox, Jarrod W., The P B ROE Valuation Model, Financial Analysts Journal, Jan Feb 1984, pp 58 66 ... dei rendimenti azionari il T model, Economia & Management 1988, v. 2, p. 93 104 http www.northinfo.com ... more details
In computational complexity theory , the parallel computation thesis is a hypothesis which states that the time used by a reasonable parallel machine is polynomially related to the space used by a sequential machine. The parallel computation thesis was set forth by Chandra and Larry Stockmeyer Stockmeyer in 1976 see References . In other words, for a computational model which allows computations to branch and run in parallel without bound, a formal language which is decidable language decidable under the model using no more than math t n math steps for inputs of length n is decidable by a machine in the unbranching model using no more than math t n k math units of storage for some constant k . Similarly, if a machine in the unbranching model decides a language using no more than math s n math storage, a machine in the parallel model can decide the language in no more than math s n k math steps for some constant k . The parallel computation thesis is not a rigorous formal statement, as it does not clearly define what constitutes an acceptable parallel model. A parallel machine must be sufficiently powerful to emulate the sequential machine in time polynomially related to the sequential space compare Turing machine , non deterministic Turing machine , and alternating Turing machine . N. Blum 1983 has introduced a model for which the thesis does not hold. However, the model allows math 2 2 O T n math parallel threads of computation after math T n math steps. See Big O notation . Parberry 1986 suggested a more reasonable bound would be math 2 O T n math or math 2 T n O 1 math , in defense of the thesis. Goldschlager 1982 has proposed a model which is sufficiently universal to emulate ..., which is where the thesis originated. References Blum, N., A note on the parallel computation ..., I., Parallel speedup of sequential machines a defense of parallel computation thesis, ACM SIGACT News , Volume 18, Issue 1, pp. 54 67, 1986. Category Parallel computing Category Theory of computation ... more details
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