The traditional description of coordination assumes noise free messages and in inifinite sequence of iterations converging to the optimum price vector p. It is shown that when communications are constrained to finite ...
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The traditional description of coordination assumes noise free messages and in inifinite sequence of iterations converging to the optimum price vector p. It is shown that when communications are constrained to finite bit length messages the price mechanism converges only to a ball surrounding p. The size of this ball depends on the size of the message truncation noise. For a given specification of the maximum size of the ball, one can find an "optimum" message length in the sense of minimizing the total number of bits transmitted.
This paper describes a structured programming and teaching system for a robot manipulator where stress is laid on the consistent integration of programming and teaching. Tn the PAL programming system being developed a...
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This paper presents a new method for synthesising decoupling controllers for linear time-invariant multivariable systems. The novel approach proposed is based on the idea of formulating, and subsequently solving, the ...
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This paper presents a new method for synthesising decoupling controllers for linear time-invariant multivariable systems. The novel approach proposed is based on the idea of formulating, and subsequently solving, the decoupling problem as an exact model-matching problem. This, in effect, results in reducing the decoupling problem to one of solving a linear system of equations.
It is desirable, from the point of view of integration, to have all the capacitors grounded in RC active filters. Recently, such a network was reported with only a preliminary design procedure. An optimal design is pr...
It is desirable, from the point of view of integration, to have all the capacitors grounded in RC active filters. Recently, such a network was reported with only a preliminary design procedure. An optimal design is presented in this paper for the above network. The new design leads to a simpler configuration, simultaneously minimizes the worst-case deviation in both the pole- Q (Q p ) and the pole frequency ω p and also guarantees that the network is free from unstable modes of operation during activation. Although this design is based on Q p and ω p , it is also suitable for notch and allpass sections. It is shown that the gains of the operational amplifiers (o.a.s.), controlling the poles of the filter, can all be made equal to (4 Q 2 p -1) 1/3 ; this choice of the gains minimizes the effect of the finite bandwidths of the amplifiers on Q p and ω p . A simple scheme is proposed to compensate for this effect. The effect of compensation on the zeros, in the case of notch and allpass sections, is also studied. It is found that the effect on the notch frequency is negligible, while, for allpass filters, compensation for the poles automatically provides compensation for the zeros. A simple tuning scheme using only resistors is also presented, and the theoretical results are verified experimentally.
Experience in the process industries has demonstrated that hierarchical (multiechelon and multilayer) control concepts are valuable in control system design. However, to date there has been relatively little work on t...
Experience in the process industries has demonstrated that hierarchical (multiechelon and multilayer) control concepts are valuable in control system design. However, to date there has been relatively little work on the development of a unified approach to hierarchical control system design. This paper defines the design problem, notes several fundamental design questions and presents some initial answers applicable to process control problems.
The Riccati equation plays an equally important role in scattering theory as in linear least-squares estimation theory. However, in the scattering literature, a somewhat different framework of treating the Riccati equ...
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The Riccati equation plays an equally important role in scattering theory as in linear least-squares estimation theory. However, in the scattering literature, a somewhat different framework of treating the Riccati equation has been developed. We show that this framework is very appropriate also for estimation problems, and that it enables us to give simple derivatitions of known results as well as to obtain several new results. Examples include the derivation of backwards equations to solve forwards Riccati equations; an analysis of the asymptotic behavior of the Riccati equation; the derivation of backwards Markovian representations of stochastic processes; and new derivations and new insights into the Chandrasekhar and related Levinson and Cholesky equations.
A certain "star-product" formalism in scattering theory as developed by Redheffer is shown to also be naturally applicable to discrete-time linear least-squares estimation problems. The formalism seems to pr...
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A certain "star-product" formalism in scattering theory as developed by Redheffer is shown to also be naturally applicable to discrete-time linear least-squares estimation problems. The formalism seems to provide a nice way of handling some of the well-known algebraic complications of the discrete-time case, e.g., the distinctions between time and measurement updates, predicted and filtered estimates, etc. Several other applications of the scattering framework are presented, including doubling formulas for the error covariance, a change of initial conditions formula, equations for a backwards Markov state model, and a new derivation of the Chandrasekhar-type equations for the constant parameter case. The differences between the discrete-time and continuous-time are noted.
The field of identification and process-parameter estimation has developed rapidly during the past decade. In this survey paper the state-of-the-art/science is presented in a systematic way. Attention is paid to gener...
The field of identification and process-parameter estimation has developed rapidly during the past decade. In this survey paper the state-of-the-art/science is presented in a systematic way. Attention is paid to general properties and to classification of identification problems. Model structures are discussed; their choice hinges on the purpose of the identification and on the available a priori knowledge. For the identification of models that are linear in the parameters, the survey explains the least squares method and several of its variants which may solve the problem of correlated residuals, viz. repeated and generalized least squares, maximum likelihood method, instrumental variable method, tally principle. Recently the non-linear situation, the on-line and the real-time identification have witnessed extensive developments. These are also reported. There are 230 references listed, mostly to recent contributions. In appendices a resumé is given of parameter estimation principles and a more detailed exposition of an example of least squares estimation. Le domaine de l'identification et de l'estimation des paramètres de processus s'est rapidement developpé durant la décade passée. Dans cette revue, l'état de l'art de cette science est présenté d'une manière systématique. Une attention est accordée aux proprietés générales et à la classification des problèmes d'identification. Les structures des modèles sont discutées; leur choix depend du but de l'identification et des informations disponibles à priori. Pour l'identification des modèles qui sont linéaires dans les paramètres, la revue explique la méthode des moindres carrés et plusieurs de ses variantes qui peuvent resoudre le problème des résidus correlés, telles que les moindres carrés iterés et généralisés, la méthode de vraisemblance maximale, la méthode de la variable influente, le principle de pointage. Rebemment, la situation non-linéaire, l'identification dans la boucle et l'identification en temps réel
In this article we introduce a new concept, structural identifiability, which plays a central role in identification problems. The concept is useful when answering questions such as: To what extent is it possible to g...
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