Linear time-invariant systemIn system analysis, among other fields of study, a linear time-invariant (LTI) system is a system that produces an output signal from any input signal subject to the constraints of linearity and time-invariance; these terms are briefly defined below. These properties apply (exactly or approximately) to many important physical systems, in which case the response y(t) of the system to an arbitrary input x(t) can be found directly using convolution: y(t) = (x ∗ h)(t) where h(t) is called the system's impulse response and ∗ represents convolution (not to be confused with multiplication).
Mode normaldroite|vignette|248px|Visualisation d'un mode normal de vibration d'une peau de tambour, constitué d'une membrane circulaire souple attachée rigidement sur la totalité de ses bords. . Pour un système oscillatoire à plusieurs degrés de liberté, un mode normal ou mode propre d'oscillation est une forme spatiale selon laquelle un système excitable (micro ou macroscopique) peut osciller après avoir été perturbé au voisinage de son état d'équilibre ; une fréquence naturelle de vibration est alors associée à cette forme.
Industrial complexThe industrial complex is a socioeconomic concept wherein businesses become entwined in social or political systems or institutions, creating or bolstering a profit economy from these systems. Such a complex is said to pursue its own financial interests regardless of, and often at the expense of, the best interests of society and individuals. Businesses within an industrial complex may have been created to advance a social or political goal, but mostly profit when the goal is not reached.
Lax pairIn mathematics, in the theory of integrable systems, a Lax pair is a pair of time-dependent matrices or operators that satisfy a corresponding differential equation, called the Lax equation. Lax pairs were introduced by Peter Lax to discuss solitons in continuous media. The inverse scattering transform makes use of the Lax equations to solve such systems. A Lax pair is a pair of matrices or operators dependent on time and acting on a fixed Hilbert space, and satisfying Lax's equation: where is the commutator.
Complexe militaro-industrielvignette|upright=1|Dwight David Eisenhower, président des États-Unis de 1953 à 1961. Son discours de fin de mandat, prononcé le 17 janvier 1961 et retransmis via la télévision américaine, reste connu sous le nom de Military-Industrial Complex Speech (lien vers Wikisource).Extrait : L'expression « complexe militaro-industriel » (CMI) désigne l'ensemble constitué par l'industrie de l'armement, les forces armées et les décideurs publics d'un gouvernement, et le jeu de relations complexes (lobbying) entre ces trois pôles destiné à influencer les choix publics.
