Central processing unitA central processing unit (CPU)—also called a central processor or main processor—is the most important processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs). The form, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged.
Bruit blancthumb|Échantillon de bruit blanc. thumb|Spectre plat d'un bruit blanc (sur l'abscisse, la fréquence ; en ordonnée, l'intensité). Un bruit blanc est une réalisation d'un processus aléatoire dans lequel la densité spectrale de puissance est la même pour toutes les fréquences de la bande passante. Le bruit additif blanc gaussien est un bruit blanc qui suit une loi normale de moyenne et variance données. Des générateurs de signaux aléatoires () sont utilisés pour des essais de dispositifs de transmission et, à faible niveau, pour l'amélioration des systèmes numériques par dither.
Boîte de SkinnerLa boîte de Skinner () est un dispositif expérimental inventé par B. F. Skinner au début des années 1930 dans le but de simplifier l'étude des mécanismes de conditionnement.
Coherent sheaf cohomologyIn mathematics, especially in algebraic geometry and the theory of complex manifolds, coherent sheaf cohomology is a technique for producing functions with specified properties. Many geometric questions can be formulated as questions about the existence of sections of line bundles or of more general coherent sheaves; such sections can be viewed as generalized functions. Cohomology provides computable tools for producing sections, or explaining why they do not exist. It also provides invariants to distinguish one algebraic variety from another.
Coherent dualityIn mathematics, coherent duality is any of a number of generalisations of Serre duality, applying to coherent sheaves, in algebraic geometry and complex manifold theory, as well as some aspects of commutative algebra that are part of the 'local' theory. The historical roots of the theory lie in the idea of the adjoint linear system of a linear system of divisors in classical algebraic geometry. This was re-expressed, with the advent of sheaf theory, in a way that made an analogy with Poincaré duality more apparent.
