A Bayesian network, Bayes network, belief network, Bayes(ian) model or probabilistic directed acyclic graphical model is a probabilistic graphical model (a type of statistical model) that represents a set of random variables and their conditional dependencies via a directed acyclic graph (DAG). For example, a Bayesian network could represent the probabilistic relationships between diseases and symptoms.
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Directed acyclic graph
In mathematics and computer science, a directed acyclic graph, is a directed graph with no directed cycles. That is, it is formed by a collection of vertices and directed edges, each edge connecting one vertex to another, such that there is no way to start at some vertex v and follow a sequence of edges that eventually loops back to v again. DAGs may be used to model several different kinds of structure in mathematics and computer science.
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Phase (waves)
Phase in sinusoidal functions or in waves has two different, but closely related meanings. One is the initial angle of a sinusoidal function at its origin and is sometimes called phase offset. Another usage is the fraction of the wave cycle which has elapsed relative to the origin.
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