Internet congestion control system is considered as a closed-loop feedback system with time-delay. A proportional-integral-differential (PID) controller is then established as active queue management (AQM) scheme to a...
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Internet congestion control system is considered as a closed-loop feedback system with time-delay. A proportional-integral-differential (PID) controller is then established as active queue management (AQM) scheme to adjust the congestion marked possibility at the links in Internet, whose parameters is auto-tuned by applying the minimization of an integral criterion for adapting the change of the network system. The simulations show that the new AQM scheme can control the size of the queue in the buffer to an expected length and has the robustness for the loading perturbation and the parameter change in the network.
In this paper a novel approach to the impulsive noise removal in color images is presented. The proposed technique employs the switching scheme based on the impulse detection mechanism using the so called peer group c...
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Iterative learning control has the potential to significantly improve the tracking performance of repeating trajectory control systems. However, until now little attempt has been made to measure this performance quant...
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Iterative learning control has the potential to significantly improve the tracking performance of repeating trajectory control systems. However, until now little attempt has been made to measure this performance quantitatively. A new iterative learning control performance index PI N is introduced which allows direct, quantitative, performance comparison of different algorithms, or alternatively a single algorithm which has variable tuning parameters. In particular, PI N can be used as a tool for selecting and adjusting algorithm tuning parameters. Application of the new performance index is demonstrated with both simulation studies and practical implementation on a gantry robot
This paper focuses on the design of autonomous and collaborative control strategies to govern the relative distances among multiple spacecraft in formation with no ground intervention. A coordinate load-sharing contro...
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This paper focuses on the design of autonomous and collaborative control strategies to govern the relative distances among multiple spacecraft in formation with no ground intervention. A coordinate load-sharing control structure for formation flying and a methodology to control their dynamic models with slow time-varying and uncertain parameters are the main objectives of this work. The method is applied to a deep space formation example, where the uncertainty in spacecraft fuel masses is also considered.
We provide an overview of the DAME project, and a discussion of the progress made to date on the development of a distributed aeroengine diagnosis environment as a proof of concept demonstration for grid computing. We...
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We provide an overview of the DAME project, and a discussion of the progress made to date on the development of a distributed aeroengine diagnosis environment as a proof of concept demonstration for grid computing. We discuss the development of a demonstration diagnosis workbench system for this complex, data intensive, diagnosis application that must be operated as a distributed 'virtual organisation'. We describe the core diagnosis applications that have been implemented as grid services, and explain how these services are being deployed within the overall diagnosis process
Telepresence aims at giving a human user the impression of being present in a remote environment. However, the user is actually situated in a user environment and his motion is tracked. A mobile teleoperator in the re...
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Telepresence aims at giving a human user the impression of being present in a remote environment. However, the user is actually situated in a user environment and his motion is tracked. A mobile teleoperator in the remote environment replicates this motion. The user can thus control the mobile teleoperator's locomotion by walking. A stereo-camera system mounted on the mobile teleoperator constantly records live camera images and transfers them to the user environment, where they are presented to the user on a head-mounted display. This paper presents a long distance experiment, in which a mobile teleoperator was controlled over a standard Internet connection by natural locomotion. Without further processing of the user's motion data, however, only exploration of a remote environment of the same size or smaller than the user environment is possible. As this is not desirable, we use motion compression, an optimal nonlinear transformation of the user's path. This algorithm allows controlling free motion in an arbitrarily large target environment from a limited user environment.
This paper is concerned with improvement of the KDI-based fault detection method so far developed by authors for nonlinear black-box systems. When modeling the system, Quasi-ARMAX model with multi-model structure is u...
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This paper is concerned with improvement of the KDI-based fault detection method so far developed by authors for nonlinear black-box systems. When modeling the system, Quasi-ARMAX model with multi-model structure is used. A fault due to unexpected change in system parameters will appear as the change of identified model. Kullback discrimination Information (KDI) can then be used as the fault detection index to evaluate the distortion in identified model. Several schemes to improve the fault detection performance are proposed, as well as the realization of a kind of fault isolation function based on a recognition approach in the model parameter space. The effectiveness of the method is verified through simulation studies on the ship propulsion system constructed for benchmark test.
In this paper a novel approach to the impulsive noise removal in color images is presented. The proposed technique employs the switching scheme based on the impulse detection mechanism using the so called peer group c...
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In this paper a novel approach to the impulsive noise removal in color images is presented. The proposed technique employs the switching scheme based on the impulse detection mechanism using the so called peer group concept. Compared to the vector median filter, the proposed technique consistently yields better results in suppressing both the random-valued and fixed-valued impulsive noise. The main advantage of the proposed noise detection framework is its enormous computational speed, which enables efficient filtering of large images in real-time applications.
In this paper, using the fuzzy theory and gray theory, a concept of the degree of fuzzy infection and a new reliability analysis method based on the relation of fuzzy infection were proposed, and the mathematical mode...
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In this paper, using the fuzzy theory and gray theory, a concept of the degree of fuzzy infection and a new reliability analysis method based on the relation of fuzzy infection were proposed, and the mathematical mode of series connection and parallel connection system was first set up and their rationalities were proven. An illustrational example was given to demonstrate the effectiveness of this theory.
Norm-optimal iterative learning control has potential to significantly increase the accuracy of many trajectory tracking tasks which can be found in industry. The algorithm can achieve very low levels of tracking erro...
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Norm-optimal iterative learning control has potential to significantly increase the accuracy of many trajectory tracking tasks which can be found in industry. The algorithm can achieve very low levels of tracking error and the number of iterations required to reach minimal error is small compared to many other iterative learning control algorithms. However, in the current format, the algorithm is not attractive to industry because it requires a large number of calculations to be performed at each sample instant. This implies that control hardware must be very fast which is expensive, or that the sample frequency must be reduced which can result in reduced performance. To remedy these problems, a revised version, fast norm-optimal iterative learning control is proposed which is significantly simpler and faster to implement. The new version is tested both in simulation and in practice on a three axis industrial gantry robot.
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