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Joint space control scheme. Joint Tactical Information Distribution system that uses spread spectrum techniques for secure digital com- joint time frequency analysis (JTFA) joint transform correlator a type of opti- cal correlator that employs two parallel paths, joystick an input device in the form of a control lever that transmits its movement in JPEG See JPEG baseline See baseline. JPEG DCT there are two DCT modes of JPEG, the sequential DCT mode and the pro- JTFA See JTIDS See jump instruction an instruction that causes an unconditional transfer of control to jump linear quadratic problem opti- mal control problem in which a controlled J = E{ Z T 0 [x 0 (t)Q(ξ(t))x(t) + u 0 (t)R(ξ(t))u(t)]dt|x(0), ξ(0)} where x(t), u(t), ξ(t) denote, respectively, process state, process control, and mode, R, Q are real valued, symmet- ric respectively positive definite and positive T is finite or infinite control hori- zon and E is an averaging operator. In the fi- nite time case the optimal control law is given u(t) = p(x(t), ξ(t), t) = −P (ξ(t), t)x(t) for each ξ(t) taking value in finite set S = {1, 2, . . . , s} where P (ξ, t) = R(ξ) −1 B 0 (ξ)K(ξ, t)x(t) where for each ξ(t) = i matrices K(i, t) are the unique positive semidefinite solutions of ξ(t) = i the pairs (A(i), √ Q(i)) are observable, then for in- finite control interval T → ∞ the solution of the jump linear quadratic (JLQ) problem u(t) = ˆp(x(t), ξ(t)) = − ˆ P (ξ(t))x(t) = −R(ξ) −1 B 0 (ξ) ˆ K(ξ)x(t) where for each ξ(t) = i matrices ˆ K(i) are the unique positive semidefinite solutions of c 2000 by CRC Press LLC |