In this paper, we review briefly some methods for minimizing a functionF(x), which proceed by follwoing the solution curve of a system of ordinary differential equations. Such methods have often been thought to be una...
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In this paper, we review briefly some methods for minimizing a functionF(x), which proceed by follwoing the solution curve of a system of ordinary differential equations. Such methods have often been thought to be unacceptably expensive; but we show, by means of extensive numerical tests, using a variety of algorithms, that the ODE approach can in fact be implemented in such a way as to be more than competitive with currently available conventional techniques.
It is shown that the classical probability generating formalism, together with the Z-transformation method, allows simple and unified derivations of the well-known computational algorithms for closed queuing networks ...
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It is shown that the classical probability generating formalism, together with the Z-transformation method, allows simple and unified derivations of the well-known computational algorithms for closed queuing networks and straightforward extensions of the algorithms to higher moments. This treatment is based on the differentiation of elementary functions and on the application of simple rules to the Z-inverse transformation. Besides the derivation of known results and extensions to higher moments, a new coalesce algorithm is obtained, as well as a new recurrence relation. The technique can be employed to derive computational algorithms for the joint moments, such as covariances of queue lengths of different job classes and at difference service centers. The main advantage of the approach lies in its simplicity, which permits painless verification of derived results, and in its generality, which allows straightforward extensions of known algorithms and the discovery of new ones.
An efficient computational scheme for solving a general class of linear time optimal control problems, where the target set is a compact and convex set with nonempty interior in the state space, is presented. The sche...
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An efficient computational scheme for solving a general class of linear time optimal control problems, where the target set is a compact and convex set with nonempty interior in the state space, is presented. The scheme is applied to solve the ship steering control problem, and excellent results are obtained.
A new algorithm to solve product form queueing networks, especially those with large numbers of centers and chains, is presented. This algorithm is a Tree version of Mean Value Analysis (MVA). Tree MVA is analogous to...
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A new algorithm to solve product form queueing networks, especially those with large numbers of centers and chains, is presented. This algorithm is a Tree version of Mean Value Analysis (MVA). Tree MVA is analogous to the Tree version of Convolution developed by Lam and Lien. Like Tree Convolution, Tree MVA allows exact solution of large networks which are intractable with previous sequential algorithms. As with the sequential versions of Convolution and MVA, Tree MVA has better numerical properties than Tree Convolution. Further, Tree MVA avoids the computational complexity of sequential MVA in networks with several queue dependent centers. Thus, we consider Tree MVA to be the best algorithm for general product form networks.
Videotex is a system which provides users with low-cost real-time access to information. In such a system, user requests are forwarded to a service computer where the desired information is retrieved and sent back to ...
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Videotex is a system which provides users with low-cost real-time access to information. In such a system, user requests are forwarded to a service computer where the desired information is retrieved and sent back to the user. In this study, we investigate the response time behavior of a videotex system where information requested by one user is broadcast to all users. A novel queueing model for broadcast delivery is developed. Using this model, we first obtain an analytic expression for the mean response time, and then we develop an efficient algorithm for its computation. Numerical results illustrating the performance characteristics of broadcast delivery are presented.
In this paper we describe a mean value analysis algorithm to solve product form queueing network models of the Baskett, Chandy, Muntz, and Palacios type (BCMP) [5]. These networks can accommodate multiple job classes ...
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In this paper we describe a mean value analysis algorithm to solve product form queueing network models of the Baskett, Chandy, Muntz, and Palacios type (BCMP) [5]. These networks can accommodate multiple job classes and load dependent service stations. The networks can be closed (i.e., jobs neither enter nor leave the network), open (i.e., jobs can enter and leave the network), or mixed (i.e., closed with respect to some job classes and open with respect to others). Two major aspects of this paper are: 1.(1)to present a unified approach to the solution of this class of BCMP queueing networks [5], and
2.(2)to thereby extend and consolidate the results of the work of several authors (Balbo, Bruell and Schwetman (1977), Bruell and Balbo (1980), Chandy and Sauer (1980), Krzesinki, Teunissen and Kritzinger (1981), Resier and Kobayashi (1975), Reiser and Lavenberg (1980), Reiser (1981), Sauer (1983), Schwetman (1980), Tucci and MacNair (1982) and Zahorjan and Wong (1981)).
The paper concludes by collecting together all the results into an explicit algorithm, MVALDMX (for mean value analysis load dependent mixed) that is a generalization of the original MVA algorithm of Reiser and Lavenberg (1978, 1980).
A hierarchical scheme for the optimal control of large-scale non linear time-delay systems is proposed. A linear approximation of original system is defined about a nominal trajectory. The system is decomposed into N ...
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A hierarchical scheme for the optimal control of large-scale non linear time-delay systems is proposed. A linear approximation of original system is defined about a nominal trajectory. The system is decomposed into N subsystems such that the delay terms as well as interaction terms can be treated as extra inputs to linear non-delay subsystems. A numerical example, constituting a 4-reservoir water resources system illustrates this approach.
A new algorithm called the tree convolution algorithm, for the computation of normalization constants and performance measures of product-form queueing networks, is presented. Compared to existing algorithms, the algo...
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A new algorithm called the tree convolution algorithm, for the computation of normalization constants and performance measures of product-form queueing networks, is presented. Compared to existing algorithms, the algorithm is very efficient in the solution of networks with many service centers and many sparse routing chains. (A network is said to have sparse routing chains if the chains visit, on the average, only a small fraction of ail centers in the network.) In such a network, substantial time and space savings can be achieved by exploiting the network's routing information. The time and space reductions are made possible by two features of the algorithm: (1) the sequence of array convolutions to compute a normalization constant is determined according to the traversal of a tree; (2) the convolutions are performed between arrays that are smaller than arrays used by existing algorithms. The routing information of a given network is used to configure the tree to reduce the algorithm's time and space requirements; some effective heuristics for optimization are described. An exact solution of a communication network model with 64 queues and 32 routing chains is illustrated. [ABSTRACT FROM AUTHOR]
The problem considered in the paper refers to the general area of developing design and computational algorithms for analysing low-sensitivity time-invariant multivariable two-dimensional systems using output feedback...
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The problem considered in the paper refers to the general area of developing design and computational algorithms for analysing low-sensitivity time-invariant multivariable two-dimensional systems using output feedback. It is seen that the matrix-minimum principle can be used to study two-dimensional digital systems with incomplete state information for the implementation of a low-sensitivity feedback law. The results show that an observer can be used in addition to the output vector to estimate the state of the system, which in turn is used for implementing the feedback law.
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