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Hidden Variable (other)
Hidden variable may refer to: * Confounding, in statistics, an extraneous variable in a statistical model that correlates (directly or inversely) with both the dependent variable and the independent variable * Hidden transformation, in computer science, a way to transform a generic constraint satisfaction problem into a binary one by introducing new hidden variables * Hidden-variable theory, in physics, the proposition that statistical models of physical systems (such as Quantum mechanics) are inherently incomplete, and that the apparent unpredictability of such systems is actually due to the influence of additional, putative yet-unseen or unmeasurable factors ** Local hidden-variable theory, in quantum mechanics, a hidden-variable theory in which distant events are assumed to have no instantaneous (or at least faster-than-light) effect on local events * Latent variable In statistics, latent variables (from Latin: present participle of ) are variables that can only be inferr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confounding
In causal inference, a confounder is a variable that influences both the dependent variable and independent variable, causing a spurious association. Confounding is a causal concept, and as such, cannot be described in terms of correlations or associations.Pearl, J., (2009). Simpson's Paradox, Confounding, and Collapsibility In ''Causality: Models, Reasoning and Inference'' (2nd ed.). New York : Cambridge University Press. The existence of confounders is an important quantitative explanation why correlation does not imply causation. Some notations are explicitly designed to identify the existence, possible existence, or non-existence of confounders in causal relationships between elements of a system. Confounders are threats to internal validity. Example Let's assume that a trucking company owns a fleet of trucks made by two different manufacturers. Trucks made by one manufacturer are called "A Trucks" and trucks made by the other manufacturer are called "B Trucks." ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden Transformation
The hidden transformation reformulates a constraint satisfaction problem in such a way all constraints have at most two variables. The new problem is satisfiable if and only if the original problem was, and solutions can be converted easily from one problem to the other. There are a number of algorithms for constraint satisfaction that work only on constraints that have at most two variables. If a problem has constraints with a larger arity (number of variables), conversion into a problem made of binary constraints allows for execution of these solving algorithms. Constraints with one, two, or more variables are called unary, binary, or ''higher-order'' constraints. The number of variables in a constraint is called its ''arity''. The hidden transformation converts an arbitrary constraint satisfaction problem into a binary one. The transformation is similar to that generating the dual problem In mathematical optimization theory, duality or the duality principle is the principle tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden-variable Theory
In physics, a hidden-variable theory is a Determinism, deterministic model which seeks to explain the probabilistic nature of quantum mechanics by introducing additional, possibly inaccessible, variables. The mathematical formulation of quantum mechanics assumes that the state of a system prior to measurement is quantum indeterminacy, indeterminate; quantitative bounds on this indeterminacy are expressed by the Heisenberg uncertainty principle. Most hidden-variable theories are attempts to avoid this indeterminacy, but possibly at the expense of requiring that Quantum nonlocality, nonlocal interactions be allowed. One notable hidden-variable theory is the de Broglie–Bohm theory. In their 1935 Einstein–Podolsky–Rosen paradox, EPR paper, Albert Einstein, Boris Podolsky, and Nathan Rosen argued that quantum entanglement might imply that quantum mechanics is an incomplete description of reality. John Stewart Bell in 1964, in his Bell's theorem, eponymous theorem proved that co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Hidden-variable Theory
In the interpretation of quantum mechanics, a local hidden-variable theory is a hidden-variable theory that satisfies the principle of locality. These models attempt to account for the probabilistic features of quantum mechanics via the mechanism of underlying but inaccessible variables, with the additional requirement that distant events be statistically independent. The mathematical implications of a local hidden-variable theory with regards to quantum entanglement were explored by physicist John Stewart Bell, who in 1964 proved that broad classes of local hidden-variable theories cannot reproduce the correlations between measurement outcomes that quantum mechanics predicts, a result since confirmed by a range of detailed Bell test experiments. Models Single qubit A collection of related theorems, beginning with Bell's proof in 1964, show that quantum mechanics is incompatible with local hidden variables. However, as Bell pointed out, restricted sets of quantum phenomena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latent Variable
In statistics, latent variables (from Latin: present participle of ) are variables that can only be inferred indirectly through a mathematical model from other observable variables that can be directly observed or measured. Such '' latent variable models'' are used in many disciplines, including engineering, medicine, ecology, physics, machine learning/artificial intelligence, natural language processing, bioinformatics, chemometrics, demography, economics, management, political science, psychology and the social sciences. Latent variables may correspond to aspects of physical reality. These could in principle be measured, but may not be for practical reasons. Among the earliest expressions of this idea is Francis Bacon's polemic the ''Novum Organum'', itself a challenge to the more traditional logic expressed in Aristotle's Organon: In this situation, the term ''hidden variables'' is commonly used, reflecting the fact that the variables are meaningful, but not observable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden Dependency
Cognitive dimensions or cognitive dimensions of notations are design principles for notations, user interfaces and programming languages, described by researcher Thomas R.G. Green and further researched with Marian Petre. The dimensions can be used to evaluate the usability of an existing ''information artifact'', or as heuristics to guide the design of a new one, and are useful in Human-Computer Interaction design. Cognitive dimensions are designed to provide a lightweight approach to analyse the quality of a design, rather than an in-depth, detailed description. They provide a common vocabulary for discussing many factors in notation, UI or programming language design. Also, cognitive dimensions help in exploring the space of possible designs through ''design maneuvers'', changes intended to improve the design along one dimension. List of the cognitive dimensions Thomas Green originally defined 14 cognitive dimensions: ; Abstraction gradient : What are the minimum and maxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden Side Effect
In computer science, an operation, function or expression is said to have a side effect if it has any observable effect other than its primary effect of reading the value of its arguments and returning a value to the invoker of the operation. Example side effects include modifying a non-local variable, a static local variable or a mutable argument passed by reference; raising errors or exceptions; performing I/O; or calling other functions with side-effects. In the presence of side effects, a program's behaviour may depend on history; that is, the order of evaluation matters. Understanding and debugging a function with side effects requires knowledge about the context and its possible histories. Side effects play an important role in the design and analysis of programming languages. The degree to which side effects are used depends on the programming paradigm. For example, imperative programming is commonly used to produce side effects, to update a system's state. By contrast, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrequent Variables
Logic optimization is a process of finding an equivalent representation of the specified logic circuit under one or more specified constraints. This process is a part of a logic synthesis applied in digital electronics and integrated circuit design. Generally, the circuit is constrained to a minimum chip area meeting a predefined response delay. The goal of logic optimization of a given circuit is to obtain the smallest logic circuit that evaluates to the same values as the original one. Usually, the smaller circuit with the same function is cheaper, takes less space, Power efficiency, consumes less power, has shorter latency, and minimizes risks of unexpected Crosstalk, cross-talk, Hazard (logic), hazard of delayed signal processing, and other issues present at the nano-scale level of metallic structures on an integrated circuit. In terms of Boolean algebra, the optimization of a complex Boolean expression is a process of finding a simpler one, which would upon evaluation ult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
