Genetic algorithms are one of the effective algorithms for hard optimization problems. They can escape from the local minima, however, the amount of their computation is often large. To decrease the amount of the comp...
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Genetic algorithms are one of the effective algorithms for hard optimization problems. They can escape from the local minima, however, the amount of their computation is often large. To decrease the amount of the computation and enhance the algorithms, the uniform design is combined into the genetic algorithm. The new genetic operator has the local-search property similar to that in traditional optimization techniques and needs a minimal amount of computation in certain meanings. Thus the new genetic algorithm can generate a diversity of population and explore the search space effectively. Moreover, the new algorithm is globally convergent. The numerical results also show the effectiveness of the new algorithm with its less computation, and higher convergent speed for all test functions.
A self – tuning PID controller algorithm has been derived in this paper. The process is identified by the regression (ARX) continuous – time model using the recursive least squares method (RLSM) with applied directi...
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A self – tuning PID controller algorithm has been derived in this paper. The process is identified by the regression (ARX) continuous – time model using the recursive least squares method (RLSM) with applied directional forgetting. The recursive parameter estimates of the continuous – time model (differential equation) are used to synthesis the PID controller. controller synthesis is designed on the basis of a dynamics inversion method. This method allows the tuning of standard analog and digital controllers for chosen types of controlled processes without or with time delay. The algorithm is suitable for the automatic setting of analog and digital PID controllers for deterministic processes or the adaptive control of stochastic and nonlinear processes. The analog modification PID controller has been verified by computer simulation.
Banyan networks are commonly used as interconnection structures in ATM switches. This paper is concerned with the replication technique which was applied to the standard banyan networks. We apply this technique to the...
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Banyan networks are commonly used as interconnection structures in ATM switches. This paper is concerned with the replication technique which was applied to the standard banyan networks. We apply this technique to the plane interconnected parallel network (PIPN) which is a switch introduced previously as a better banyan-based interconnection structure. The normalized throughput of unbuffered and buffered replicated PIPN is analyzed analytically under uniform traffic model. We apply the simulation technique to verify the analytical results under the uniform traffic model and to study the performance of different heterogeneous traffic models. The performance is shown to increase significantly when the replicated PIPN is used which supports the idea of using this switch as a new high-performance ATM switch.
In this paper, an adaptive decentralized controller is presented to attenuate the transversal vibration of a flexible cablestayed bridge induced by seismic excitation, in which only local sensor information has been u...
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Static task scheduling in distributed computing systems is a very complex problem and known to be NP-hard. This problem is even harder when the module execution times become probabilistic. In this paper we study the e...
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Static task scheduling in distributed computing systems is a very complex problem and known to be NP-hard. This problem is even harder when the module execution times become probabilistic. In this paper we study the effect of probabilistic module execution times on the performance of task-scheduling algorithms. We show that in static task scheduling, for probabilistic module execution times, and in the existence of some factors there is no need to use an expensive task-scheduling algorithm. Given any two static task-scheduling algorithms that use deterministic module execution times in assigning task modules to the distributed system, the performance of these two algorithms will not remain the same when these module execution times become probabilistic rather than deterministic. We also study the effects of some factors an our results.
Object-oriented database systems aim at meeting the data modelling, performance, cooperative design and version management requirements of current advanced applications, such as CAD (computer-aided design), CAM (compu...
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Object-oriented database systems aim at meeting the data modelling, performance, cooperative design and version management requirements of current advanced applications, such as CAD (computer-aided design), CAM (computer-aided manufacturing), CASE (computer-aided software engineering), CIM (computer integrated manufacturing), hypermedia and expert systems. This paper presents the ALEX Object Manager, which is a part of the ALEX object-oriented database management system that is being developed based on the ODMG-93 standard. The system decomposition and process layout are presented, some implementation problems are discussed and the current status of the system is reported.
In this paper is presented a new approach to robust non-linear control design, which can guarantee a prescribed decay rate of exponential stability for known system uncertainties. The proposed approach doesn’t employ...
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In this paper is presented a new approach to robust non-linear control design, which can guarantee a prescribed decay rate of exponential stability for known system uncertainties. The proposed approach doesn’t employ matching conditions. The non-linear power system with deterministic uncertainties is chosen as demonstration example.
This paper presents a model-based approach to fault detection of dynamic systems, which is robust to unmodeled dynamics. A “Quasi-ARMAX model᾿ is first proposed for describing nonlinear systems by incorporating a gro...
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This paper presents a model-based approach to fault detection of dynamic systems, which is robust to unmodeled dynamics. A “Quasi-ARMAX model᾿ is first proposed for describing nonlinear systems by incorporating a group of certain nonlinear structures into a linear ARMAX structure. The model can be used for a best linear approximation of the system, as well as for the estimation of resulting unmodeled dynamics, by a hierarchical implementation of recursive identification. Then robust fault detection is performed based on thresholding approach using Kullback discrimination information as fault detection index, in which the estimated unmodeled dynamics is incorporated.
This research is concerned with fault detection of nonlinear systems using Kullback discrimination information (KDI) as an index. A hybrid quasi-ARMAX model is proposed, which combines a linear ARMAX model and a multi...
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This research is concerned with fault detection of nonlinear systems using Kullback discrimination information (KDI) as an index. A hybrid quasi-ARMAX model is proposed, which combines a linear ARMAX model and a multi-ARX-model based on interpolation. In the case where the faults occur on the ARMAX model part, a KDI-based "robust" fault detection is performed, in which multi-ARX-model part is treated as error due to nonlinear undermodeling. In other cases, the model is transformed into several local ARMAX models and fault detection is performed by using the KDI to discriminate each identified local model. In this paper, we mainly concentrate our discussion on the latter cases.
The paper focuses on the speed control of stepping motors in a closed-loop configuration. An incremental optical encoder is used as the position transducer, allowing the achievement of a minor loop. The numerical cont...
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The paper focuses on the speed control of stepping motors in a closed-loop configuration. An incremental optical encoder is used as the position transducer, allowing the achievement of a minor loop. The numerical control algorithm is implemented using an IBM PC together with a specialized interface for stepper motors. The solution was obtained in two steps: the first was a nonlinear control law and the second was the improvement of the first one by using a PI part.
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