to Einstein s assertion that Local hiddenvariabletheory local hidden variables are impossible ... the famous theorem by von Neumann that no hiddenvariabletheory reproducing the statistical predictions ... it is a hiddenvariabletheory. The major reference for Bohm s theory today is his posthumous ... that affect the validity of the experimental findings. Non local hiddenvariabletheory Assuming the validity of Bell s theorem, any classical hiddenvariabletheory which is consistent with quantum ... hiddenvariabletheory was the pilot wave pilot wave theory of Louis de Broglie , dating from 1927. The currently best known hiddenvariabletheory, the Bohm interpretation Causal Interpretation , of the physicist and philosopher David Bohm , created in 1952, is a non local hiddenvariabletheory ... See also Local hiddenvariabletheory Bell s theorem Bell test experiments Quantum mechanics Bohm interpretation DEFAULTSORT HiddenVariableTheory Category Quantum measurement Category Hiddenvariable ...Two other uses a class of quantum mechanics theories hidden variables in economics latent variable other ... of quantum mechanics Interpretations Historically, in physics , hiddenvariable theories were ... hidden beneath quantum mechanics, to be described by a more fundamental theory that can always ... foundation property &mdash the hiddenvariable. Others, however, believe that there is no deeper reality in quantum mechanics &mdash experiments have shown a vast class of hiddenvariable ... ions, quantum mechanics conflicts with hiddenvariable theories regardless of the quantum state ... for physicists looking for hiddenvariable theories, nondeterministic theories trying to explain ... hiddenvariable theories for example Edward Nelson s Stochastic interpretation stochastic mechanics ... is correct the Bell inequality would be violated. Another no go theorem concerning hiddenvariable theories ... . This rules out local hiddenvariable theories, but does not rule out non local ones which would ... more details
In quantum mechanics , a local hiddenvariabletheory is one in which distant events are assumed to have ... A, 98 , 5 9 1983 See also Hiddenvariabletheory Category Quantum measurement Category Hiddenvariable ... math A math with hiddenvariable math lambda math by detector math A math , set in direction math ... behaviour of local hiddenvariable models. When John Stewart Bell John Bell originally derived his inequality ... 1 2 particles. They were conducted instead using photons. The local hiddenvariable prediction ... by a real vector, pointing in any direction. It will be the hiddenvariable in our model. Taking it to be a unit vector, all possible values of the hiddenvariable are represented by all points ... which their hiddenvariable falls. Assuming the source to be rotationally invariant to produce all .... The quantum mechanical prediction is the dotted curve. Thus the local hiddenvariable prediction ... light Clauser, 1978 . It is not assumed that every single one is detected. Instead the hiddenvariable ... the role of time in constructing hidden variables theory. One approach is suggested by K. Hess and W. Philipp Hess, 2002 and discusses possible consequences of time dependences of hidden variables ... Hidden variables and hidden time in quantum theory , a preprint 33 by Keldysh Inst. of Appl ... theory of quantum mechanics, on the other hand, distant events may under some circumstances ... that there can be no interpretations of quantum mechanics which use local hidden variables. The term ... physics and not to quantum mechanics. Local hidden variables and the Bell tests The principle ... outcomes being partly determined by other hidden variables local to the analyser and detector. It is assumed that these other hidden variables are independent on the two sides of the experiment ... , the usual one being that these are both cosine squares, in line with Malus Law. Assuming the hiddenvariable to be polarisation direction parallel on the two sides in real applications, not orthogonal ... more details
Hidden variables may refer to HiddenvariabletheoryHiddenvariable theories , in physics a class of theories trying to explain away the statistical nature of quantum mechanics Latent variable s, in statistics, variables that are inferred from other observed variables Hidden transformation , in computer science, a way to transform a generic constraint satisfaction problem into a binary one by introducing new hidden variables Confounding or hidden variables in general. That is, a variable that actually creates the illusion of a causal relation e.g. firemen often appear after smoke, not because smoke causes firemen, but because fire causes both smoke and firemen dab Category Hidden variables ... more details
Unreferenced auto yes date December 2009 Orphan date February 2009 Regionalized variabletheory RVT is a geostatistics geostatistical method used for interpolation in space. The concept of the theory is that interpolation from points in space should not be based on a smooth continuous object. It should be, however, based on a stochastic model that takes into consideration the various trends in the original set of points. The theory considers that within any dataset, three types of relationships can be detected Structural part, which is also called the trend. Correlated variation. Uncorrelated variation, or noise. After defining the above three relationships, RVT then applies the first law of geography , in order to predict the unknown values of points. The major application of this theory is the Kriging method for interpolation. Category Interpolation DEFAULTSORT Regionalized VariableTheory Science stub ... more details
Wiktionarypar variable wikiversity Variable may refer to Variable research , a logical set of attributes Variable mathematics , a symbol that represents a quantity in an algebraic expression. Variable computer science , a symbolic name associated with a value and whose associated value may be changed Variable star , a type of star as in astronomical object Dependent and independent variables in statistics disambig Category Variables bg ca Variable de Variable el es Variable desambiguaci n eu Aldagai argipena fa fr Variable it Variabile ja pl Zmienna pt Vari vel sk Premenn ckb sr fi Muuttuja ... more details
Infobox television episode Title The Variable Series Lost TV series Lost Image Caption Season 5 Episode ... List of Lost episodes Prev Some Like It Hoth Next Follow the Leader Lost Follow the Leader The Variable ... directly with the concept of time travel . The Variable also features the death of Daniel, portrayed ... abc.go.com primetime lost index?pn recap t 162212&d 191111 title Lost Episode Recaps The Variable publisher ... Lindelof and Carlton Cuse , the show runner s of Lost The Variable was written by Edward Kitsis and Adam .... ref name n&o In The Variable , the viewers would get a few more pieces of the puzzle, Lindelof ..., 2009 work Access Hollywood accessdate 2009 05 04 ref The Variable was the hundredth episode of the show ... in the episode. The Variable was watched live or recorded and watched within five hours of broadcast .... ref cite web url http tv.ign.com articles 978 978209p1.html title Lost The Variable Review last Carabott ... eyes, we decided to forgive him. But The Variable showed us the dynamic at the heart of Daniel s stuttering ... www.pastemagazine.com blogs tv detail 2009 04 lost review the variable episode 514.html title Lost Review The Variable last Dovey first Rachel date April 30, 2009 work Paste accessdate 2009 05 10 ref ... that Lost had been too slow lately, here you go. Those who watched The Variable saw more action ... Review Lost The Variable last Sweeney first Adam date May 1, 2009 publisher Film School Rejects accessdate ... quotTHE VARIABLEquot Page1.html title Thud Review Lost The Variable last Oliver first David date ... 2009 04 30 lost 514 the variable title LOST 5.14 The Variable last Lackey first Stephen date ... s parents. ref cite web url http www.airlockalpha.com node 6311 title Lost The Variable last ... lost the variable title Lost The Variable first Fred date April 30, 2009 publisher TVoholic.com accessdate 2009 05 10 ref Jon Lachonis of TVOvermind said that as an internal character piece, The Variable ... to who Daniel truly was. ref cite web url http www.tvovermind.com tv news lost lost the variable ... more details
Wiktionarypar hidden selfref For the Wikipedia template nowiki hidden nowiki , see Template HiddenHidden or The Hidden can refer to Concealment , keeping things from notice or view L Encobert in Catalan El Encubierto in Spanish The Hidden One , a mysterious rebel leader in the Revolt of the Brotherhoods in Valencia in 1522 Hidden 2005 film Hidden 2005 film originally released under the name Cach , a 2005 French drama film Hidden album Hidden album , a 2010 album by British group These New Puritans Hidden Torchwood Hidden Torchwood , a Torchwood spin off audiobook Hidden 2009 film Hidden 2009 film , a 2009 Norwegian horror film Hidden TV series Hidden TV series , a 2011 BBC television drama The Hidden film The Hidden , a 1987 science fiction horror film The Hidden novel The Hidden novel , a 2006 suspense novel by Kathy Mackel The Hidden game developer , a defunct British game developer The Hidden video game The Hidden video game , a modification to the computer game Half Life 2 The Hidden Animorphs The Hidden Animorphs , the thirty ninth book in the Animorphs series by K.A. Applegate. The Hidden The Penguins of Madagascar episode The Hidden The Penguins of Madagascar episode , an episode of The Penguins of Madagascar Disambig pt Hidden ... more details
. See also Latent variable model Item response theory Rasch model References Reflist 2 Reflist 3 DEFAULTSORT Latent Variable Category Social sciences Category Bayesian networks Category Econometric models Category Statistical models Category Statistical terminology Category Latent variable models Latent variable Category Psychometrics af Latente veranderlike da Skjult variabel de Latente Variable fa ...In statistics , latent variables as opposed to observable variable s , are Variable mathematics variables that are not directly observed but are rather inferred through a mathematical model from other variables that are observed directly measured . Mathematical models that aim to explain observed variables in terms of latent variables are called latent variable model s. Latent variable models are used in many disciplines, including economics , machine learning artificial intelligence , bioinformatics , natural language processing , psychology , and the social sciences . Sometimes latent variables correspond to aspects of physical reality, which could in principle be measured, but may not be for practical reasons. In this situation, the term hidden variables is commonly used reflecting the fact that the variables are really there , but hidden . Other times, latent variables correspond to abstract concepts, like categories, behavioral or mental states, or data structures. The terms hypothetical variables or hypothetical constructs may be used in these situations. One advantage of using latent variables is that it Dimensionality reduction reduces the dimensionality of data. A large number of observable variables can be aggregated in a model to represent an underlying concept, making it easier to understand the data. In this sense, they serve a function similar to that of scientific ... of the more predominant means of assessing wisdom include wisdom related performance and latent variable ...&ndash 320 at p. 291 ref Common methods for inferring latent variables Hidden Markov model s Factor ... more details
In type theory and programming language s, a type variable is a Variable mathematics mathematical variable ranging over data types types . Even in programming languages that allow variable programming mutable variable s, a type variable remains an abstraction, in the sense that it does not correspond to some memory locations. Programming language s that support parametric polymorphism make use of universally quantified type variables. Languages that support existential type s make use of existentially quantified type variables. For example, the following OCaml code defines a polymorphic identity function that has a universally quantified type, which is printed by the interpreter on the 2nd line let id x x val id a a fun In mathematical notation, the type of the function code id code is math forall a.a to a math , where a is a type variable. See also System F type theory stub Category Functional programming pl Zmienna typowa ... more details
Unreferenced date December 2007 For the notion of a controlled variable, see independent variable . The term Control Variable has different meanings, depending on the area place in which it is used. The control variable is something that is constant and unchanged in an experiment. In scientific experimentation, a control variable is the one that must not be changed throughout an experiment because it affects the dependent variables and thus affects the outcome of the experiment. For example, in the experimental verification of Boyles law, the temperature must be kept constant. Essentially, a controlled variable is what is kept the same throughout the experiment. An example of a controlled variable would be if you have experimented on plants and tested a product on two plants, the soil and the pot would be two controlled variables. A control variable is any factor that remains unchanged and strongly influences values also a factor held constant to test the relative impact of an independent variable. Control theory In control theory , controlled variables are the variables that are input to the control system. Reaction rate is the dependent variable and everything else that can change the reaction rate must be controlled kept constant so that you only measure the effects of concentration. Variables that need to be controlled in this case include temperature, catalyst, surface area of solids, and pressure. If not controlled, they complicate the experiment and hence, the test is less valid. For example, a control variable could be time or mass or each marble had ten minutes to dissolve in acid. Computer Programming In computer programming , a control variable is a program variable ... control variable is used to regulate the number of times the body of a program loop is executed ... variable can identify the present State computer science state of a computer program Category Experiments ca Variable de control simple Control variable ... more details
In statistics , observable variables or manifest variables , as opposed to latent variable s, are those Variable mathematics variables that can be observed and directly measured. ref Dodge, Y. 2003 The Oxford Dictionary of Statistical Terms , OUP. ISBN 0 19 920613 9 ref See also Observables in physics Observability in control theory Latent variable model References references Category Social sciences Category Econometrics Category Statistical terminology Econometrics stub statistics stub ... more details
about the engineering indicator the mathematical concept used in thermodynamics process function A process variable , process value or process parameter is the current status of a process under control. An example of this would be the temperature of a furnace. The current temperature is called the process variable, while the desired temperature is known as the setpoint control system set point . Measurement of process variables are important in controlling a process. The process variable is a dynamic feature of the process which may change rapidly. Accurate measurement of process variables is important for the maintenance of accuracy in a process. There are four commonly measured variables which affect chemical and physical process pressure , Thermodynamic temperature temperature , level and flow. cn date December 2011 Tech stub DEFAULTSORT Process Variable Category Control theory ... more details
as random variables. More recently, nuisance variable has been used in the same context. ref Irving ... 0471385131 ref Nuisance variable has been used in the context of statistical surveys to refer information ... Sanderman, Jim C. Coyne, Adelita V. Ranchor 2006 Age Nuisance variable to be eliminated with statistical ... of interest. The term nuisance variable is sometimes also used in more general contexts ... 2009 as the term nuisance parameter has a specific meaning in statistical theory. References references Category Stochastic processes Category Latent variable models Category Statistical terminology ca Variable destorb es Variable estorbo ... more details
In computer science , a local variable is a Variable programming variable that is given local scope programming scope . Such a variable is accessible only from the subroutine function or block programming block in which it is declared. In programming language s with only two levels of visibility, local variables are contrasted with global variables . On the other hand, many ALGOL derived languages allow any number of levels of nested function s with private variables, functions, constants and types hidden within them. In most languages, local variables are automatic variable s stored on the call stack directly. This means that when a recursion computer science recursive function calls itself ... with side effect computer science side effects that can occur with global variable global variables . Static local variables A special type of local variable, called a static local, is available in many ... allocated variable. In all of the above languages, static variables are declared as such with a special ... Static variable several different meanings in various languages. code local code in Perl Perl has a keyword ... ref It gives a temporary, scope programming dynamically scoped value to a global package variable, which lasts until the end of the enclosing block. However, the variable is visible to any function called ... variable a is modified to a new temporary local meaning inside f , but the global value is restored ... printed 1 three times since in that case the code a code variable is really local to the scope of the function ... also by Perl, but in this case, the notation was made simpler a global variable name must be preceded by a sign, like code variable name code , while a local variable has simply no sign in front of its name, like code variable name code while in perl all scalar values have a in front . See also Global variable Non local variable References references DEFAULTSORT Local Variable Category Variable computer programming et Lokaalne muutuja es Variable local fr Variable locale is Sta v r breyta ja ... more details
The term dummy variable can refer to either of the following Bound variable &ndash in mathematics and computer science, a placeholder variable Dummy variable statistics &ndash an indicator variable. disambig ... more details
Unreferenced date December 2009 Critical variables are defined, for example in thermodynamics , in terms of the values of variables at the critical point physics critical point . On a PV diagram, the critical point is an inflection point . Thus math left frac partial P partial V right C 0 math math left frac partial 2 P partial V 2 right C 0 math For the van der Waals equation , the above yields math P C frac a 27b 2 math math displaystyle V C 3nb math math T C frac 8a 27bR math DEFAULTSORT Critical Variable Category Thermodynamics Category Conformal field theory ca Variable cr tica ... more details
In Probability theory probability and statistics , a random variable or stochastic variable is, roughly speaking, a Variable mathematics variable whose value results from a measurement on some type of random ... theory measure theoretic terms, we use the random variable X to push forward the measure ... DEFAULTSORT Random Variable Category Probability and statistics Category Probability theory Category ... is superfluous. Intuitively, a random variable is a numerical description of the outcome of an experiment ... as either discrete a random variable that may assume either a finite number of values or an infinite sequence of values or as continuous a variable that may assume any numerical value in an interval or collection of intervals . A random variable s possible values might represent the possible ..., a random variable can be thought of as a quantity whose value is not fixed, but which can ... values occurring. Realizations of a random variable are called random variate s. Random variables are usually real valued, but one can consider arbitrary types such as indicator random variable ... variables, and then the mapping function included in the definition of a random variable becomes important. As an example, the square of a random variable distributed according to a standard normal distribution is itself a random variable, with a chi squared distribution . One way to think of this is to imagine ... independent identically distributed random variables. Since each sample is a random variable, the sample mean is a function of random variables and hence a random variable itself, whose distribution ... , or extent to which the values are dispersed of the variable can be computed. There are several ... 1999 isbn 0534209343 ref A Discrete probability distribution discrete random variable maps outcomes ... variable maps outcomes to values of an uncountable set e.g., the real number s . For a continuous random variable, the probability of any specific value is zero, whereas the probability of some infinite ... more details
refimprove date September 2010 In mathematics , a variable is a value mathematics value that may change ... as being either a dependent variable or an independent variable . Independent variables are regarded ... variable and the other values are independent variables. The notation f x is used for the value of the function f with x representing the independent variable. Similarly, notation such as f x , y ... for a variable to vary Varying, in the context of mathematical variables, does not mean change in the course of time, but rather dependence on the context in which the variable is used. This can be the immediate context of the expression mathematics expression in which the variable occurs, as in the case ... being defined. The context can also be larger, for instance when a variable is used to designate ..., and alternative names can be used instead of variable a parameter is a value that is fixed in the statement of the problem being studied although its value may not be explicitly known , an unknown is a variable ... for anything else but is an abstract value in itself. In all these cases the term variable is often ... is a variable standing for the argument of the function being defined, which can be any real number. In the identity math sum i 1 n i frac n 2 n 2 math the variable i is a summation variable which designates ... a discrete set of values while n is a parameter it does not vary within the formula . In the theory ... while x is called a variable. When studying this polynomial for its polynomial function this x ... notion of a variable, because the quantities E , m , P , V , n , and T are instead used to designate ... are conventionally called x , y , and z , while random variable s in statistics are usually named ..., in the formula x 1 5, x is a variable which represents an unknown number . Variables are often ... 6 or 3 2 2 55 55 55 110 or 55 2 etc. So in this example, the variable x is a placeholder for any number that is to say, a variable. One important thing we assume is that the value of x does not change ... more details
. For the general motor variable z a b j , one has math e z e a cosh b j sinh b math . In the theory of functions of a motor variable special attention should be called to the square root and logarithm ... theory of the bireal variable. The essay was studied at University of British Columbia in 1949 when Geoffry Fox wrote his master s thesis Elementary function theory of a hypercomplex variable and the theory of conformal mapping in the hyperbolic plane . On page 46 Fox reports Bencivenga has shown that a function of a bireal variable maps the hyperbolic plane into itself in such a manner ...A function of a motor variable is a function mathematics function with arguments and values in the split complex number plane, much as functions of a complex variable involve ordinary complex number s. The split ..., functions depending on a motor variable provide a tool for mathematical model s. which date December 2010 Elementary functions of a motor variable Let D math z x y jmath x,y in R math , the split complex ... called Mobius transformation s. For the motor variable the analogous functions are constructed with inversive ... of similar differential operators to establish the relation of harmonic function theory to analytic ... on the motor variable to the university s annual periodical. He is the sole author of the introductory ... of real numbers this property permits explication of the theory of series and of functions of the hyperbolic complex variable through the use of properties of the field of real numbers. He ... of the motor variable. p In the primary article, cited below, he considers D holomorphic functions ... Isotropic rectangles play a fundamental role in this theory since they form the domains of existence ... in laying out the main lines of the theory that lies between real and ordinary complex analysis. The text ... Borel s geometry so as to underwrite its motivation. p Bireal variable In 1892 Corrado Segre recalled ... planar decompositions polar decomposition of a bireal variable and discusses hyperbolic orthogonality ... more details
For the novel by Robert A. Heinlein and Spider Robinson Variable Star Image V838 Monocerotis expansion.jpg 300px right thumb Images showing the expansion of the light echo of a red variable star, the V838 Monocerotis A star is classified as variable if its apparent magnitude as seen from Earth changes ... to classify variable stars as belonging to one of two types Intrinsic variables, whose luminosity ... The first variable star was identified in 1638 when Johannes Phocylides Holwarda Johannes Holwarda ... ancient philosophers had taught. In this way, the discovery of variable stars contributed to the astronomical revolution of the sixteenth and early seventeenth centuries. The second variable star to be described was the eclipsing variable Algol , by Geminiano Montanari in 1669 John Goodricke ... Kirch G. Kirch , then R Hydrae in 1704 by Giovanni Domenico Maraldi G. D. Maraldi . By 1786 ten variable ... the number of known variable stars has increased rapidly, especially after 1890 when it became possible to identify variable stars by means of photography. The latest edition of the General Catalogue of Variable Stars ref http www.sai.msu.su gcvs gcvs iii html ref 2008 lists more than 46,000 variable ... data with observed spectral changes, astronomers are often able to explain why a particular star is variable. Variable star observations Variable stars are generally analysed using photometry astronomy ... amplitude can be very well established for many variable stars, though, these quantities may vary ... scientific study of variable stars by visually comparing the star with other stars within the same telescope telescopic field of view of which the magnitudes are known and constant. By estimating the variable ... Association of Variable Star Observers collects such observations from participants around ... light curves with spectral data often gives a clue as to the changes that occur in a variable ... moves to and from us, in the same tempo as its brightness varies. About two thirds of all variable ... more details
In object oriented programming , a member variable sometimes called a member Field computer science field is a variable programming variable that is associated with a specific Class computer science class , and accessible for all its method computer science methods . If there is only one copy of the variable shared with all instances of the class, it is called a class variable or static member variable. If each instance of the class has its own copy of the variable, the variable is called an instance variable . ref cite web accessdate 2011 08 12 author Richard G. Baldwin date 1999 03 10 location http www.dickbaldwin.com publisher Richard G Baldwin Programming Tutorials title Q What is a member variable? quote A member variable is a member of a class class variable or a member of an object instantiated from that class instance variable . It must be declared within a class, but not within the body of a method of the class. url http www.dickbaldwin.com java Java020.htm ref References Reflist 2 See also Global variable Local variable Category Object oriented programming Category Variable computer programming Compu prog stub ... more details
In computer programming , variable shadowing occurs when a variable declared within a certain scope decision block, method, or inner class has the same name as a variable declared in an outer scope. This outer variable is said to be shadowed. This can lead to confusion, as it may be unclear which variable subsequent uses of the shadowed variable name refer to. One of the first languages to introduce variable shadowing was ALGOL , which first introduced blocks to establish scopes. It was also permitted by many of the derivative programming languages including C and Java programming language Java . The C Sharp programming language C language breaks this tradition, allowing variable shadowing between an inner and an outer class, and between a method and its containing class, but not between an if block and its containing method, or between case statements in a Switch statement switch block. Example The following Java programming language Java code provides an example of variable shadowing. source lang java class VariableShadowing static int x 1 public static void main String args This local variable shadows the class variable int x 100 This statement prints the local variable System.out.println Local variable x x 100 This statement prints the shadowed variable System.out.println Class variable x VariableShadowing.x 1 source See also Overloading Type polymorphism Category Variable computer programming ... more details
Unreferenced date December 2009 In computer science , an induction variable is a variable that gets increased or decreased by a fixed amount on every iteration of a loop, or is a linear function of another induction variable. For example, in the following loop, code i code and code j code are induction variables for i 0 i 10 i j 17 i Application to strength reduction A common compiler optimization is to recognize the existence of induction variables and replace them with simpler computations for example, the code above could be rewritten by the compiler as follows, on the assumption that the addition of a constant will be cheaper than a multiplication. j 17 for i 0 i 10 i j j 17 This optimization is a special case of strength reduction . Application to reduce register pressure In some cases, it is possible to reverse this optimization in order to remove an induction variable from the code entirely. For example extern int sum int foo int n int i, j j 5 for i 0 i n i j 2 sum j return sum This function s loop has two induction variables code i code and code j code . Either one can be rewritten as a linear function of the other therefore, the compiler may optimize this code as if it had been written extern int sum int foo int n int i for i 0 i n i sum 5 2 i 1 return sum Induction variable substitution Induction variable substitution is a compiler transformation to recognize variables which can be expressed as functions of the indices of enclosing loops and replace them with induction variables with the expressions involving loop indices. This transformation makes the relationship between the variables and loop indices explicit, which helps other compiler analysis, such as dependence analysis . Example. Input code int c, i c 10 for i 0 i 10 i c c 5 c is incremented by 5 for each ... last Jones chapter Reduction of Operator Strength title Program Flow Analysis Theory and Applications ... CRPC TR95635 S.pdf accessdate April 22, 2010 doi DEFAULTSORT Induction Variable Category Compiler ... more details
In statistics and social sciences , an antecedent variable is a Variable mathematics variable that can help to explain the apparent relationship or part of the relationship between other variables that are nominally in a Causality cause and effect relationship. In a regression analysis , an antecedent variable would be one that influences both the independent variable and the dependent variable . See also Path analysis statistics Latent variable Intervening variable References Olobatuyi M.E. 2006 A user s guide to path analysis , University Press of America. ISBN 0761832300 Chapter 2 Category Statistical terminology Category Regression analysis Category Statistical dependence Category Design of experiments stats stub ... more details
Unreferenced date December 2009 A state variable is one of the set of variables that describe the state of a dynamical system . Intuitively, the state of a system describes enough about the system to determine its future behaviour. Models that consist of coupled first order differential equations are said to be in state variable form ref cite book author William J. Palm III year 2010 title System Dynamics edition 2nd publisher page 225 isbn ref Examples In simple mechanics mechanical systems , position coordinates and their derivatives are typical state variables knowing these, it is possible to determine the future state of the objects in the system. In a Thermodynamics thermodynamic system , state function s are properties such as thermodynamic temperature temperature , pressure , volume , internal energy , enthalpy , and entropy . In ecosystem model s, population sizes or concentrations of plants, animals and resources nutrients, organic material are typical state variables. Control Systems Engineering In Control Engineering and other areas of science and engineering, state variables are used to represent the states of a general system. The state variables can be used to describe the state space controls state space of the system. The equations relating the current state and output of a system to its current input and past states are called the state equations. The state equations for a linear time invariant system are expressed with Coefficient Matrix mathematics matrices ... Discrete Time Systems The state variable representing the current state of a discrete time system i.e. ... u n to the system. Continuous Time Systems Analog The state variable representing the current state .... See also State space controls Control theory Equation of state State computer science Dynamical systems State functional analysis State diagram State variable filter References Reflist DEFAULTSORT State Variable Category Physics ... more details
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