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In a large class of multi-loop control systems, many feedback loops are "closed" through a timeshared digital computer, using algorithms which require information from sources which are sampled at a rate which is not synchronized with the sampling of the individual "Plants". This mis-synchronization, in conjunction with variations in the computer's task load caused by "interrupts",...
Many future NASA programs require very high accurate pointing stability. These pointing requirements are well beyond anything attemped to date. This paper suggests a control system which has the capability of meeting these requirements. An optimal control law for the suggested system is specified. However, since no direct method of solution is known for this complicated system, a computation technique...
A cost functional, which is the integral of a cost rate over a random time, is associated with a control system described by a stochastic differential equation. The control policy is confined to measurable Markov controls. In connection to the problem of selecting a minimizing control, two results are shown in this paper. The first one is the continuity dependence of the cost functional on controls,...
This paper deals with the realization of a best approximation of an unknown optimal decision rule by means of a self-learning hierarchical system. This optimization implies the simultaneous use of adaptive estimation and classification techniques. An unsupervised learning discrete algorithm based on stochastic approximation theory is proposed as a solution to this problem. Some applications are suggested,...
The notion of a goal has been useful in forming conceptual models about decision systems and in general about systems which exhibit purposeful behavior. While the term "goal" is used quite frequently it is surprising that such an intuitively useful notion has remained so ambiguous. This paper formalizes the notion of a goal and discusses some of its properties and characteristics. This formalization...
A class of differential games with two pursuers versus one evader is investigated for Nash equilibrium solutions. The solutions show that the state space can be partitioned into the following three regions: (i) the evader, E, plays a two-player, nonzero-sum differential game against one of the two pursuers, P, and ignores the other pursuer, Q; (ii) the evader plays a two-player, nonzero-sum differential...
In this paper the discrete-time optimal control sensitivity problem is stated and a computationally convenient solution algorithm is reviewed. The algorithm is used to calculate the sensitivity of optimal public investment with respect to parameters in a regional model and welfare index. Implications of these results for regional development strategies are discussed.
The purpose of this work is to formulate, analyze, and resolve structural stability of competitive economic systems in the Hicks-Metzler algebraic setting by using mathematical methods of the comparison principle and the vector Liapunov functions. A large economy is decomposed into interrelated sub-economies with time-varying interactions. Stability of the economy is determined on the basis of the...
Adaptive antennas provide automatic adjustment of the radiation pattern to enhance the desired signal and minimize any interference sources that are present. Unfortunately, certain environments result in very slow convergence if conventional algorithms are used. This paper investigates the constraints that must be satisfied and presents computer simultation results for two unconventional techniques...
This paper deals with the convergence of optimal control algorithms in the sense of control measures. Specifically, it shows, as a corollary, that most optimal control algorithms construct sequences of controls which always converge in cost to a local minimum.
This paper presents several new algorithms for solving optimal control problems with general constraints on the control and inequality constraints on the terminal state. The algorithms are of the differential dynamic programming (strong variation) type. Thus the algorithms generate, at each iteration, a new control which is equal to a "minimising" control u on a subset I?(u) ? T and equal...
This paper summarizes an analysis of penalty and multiplier methods for constrained minimization, contained in Refs. [1-3]. We describe global convergence and rate of convergence results for multiplier methods, as well as a global duality theory for nonconvex problems. A main qualitative conclusion is that multiplier methods avoid to a substantial extent the traditional disadvantages of penalty methods...
This paper summarizes two high-speed, adaptive modems for voice-band channels. The first is a 4800 bps, MOS/LSI modem which is almost entirely contained on 5 to 8 MOS/LSI chips, depending upon the version. The second modem is experimental and employs advanced, novel techniques for automatic equalization, carrier recovery, timing recovery, and jitter correction. Partial response, SSB signaling provides...
Our society is in a state of massive transition. For the first half of this century, resources were substantially unlimiting and manpower was in short supply. Now, the situation is almost reversed. Technological advances have made such claims on natural resources that they are now quickly becoming in short supply. The same technological advances have greatly reduced the need for manpower in many activities...
It is shown how globally stable model reference adaptive control systems may be designed using only the plant's input and output signals. Controllers for single input-single output, nonlinear, nonautonomous plants are developed based on Liapunov's direct method and the Meyer-Kalman-Yacubovich lemma. Filtered derivatives of the plant output replace pure derivatives which are normally required in these...
Optimal maintenance policies for a machine with degradation in performance with age and subject to failure are derived using optimal control theory. The optimal policies are shown to be, normally, of bang-coast nature, except in the case when probability of machine failure is a function of maintenance. It is also shown, in the deterministic case that a higher depreciation rate tends to reverse this...
This paper is a survey of a study implemented during the last two years, considering the correction (unfolding) of smearing effects due to instrumental resolution in physical experiments (neutron - and X-ray scattering). In order to obtain as well on-line as interactive situations of treatment of data, sequential methods were studied. Two classes of problems have been treated. In the first one no...
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