A new approach to analysis of robot stability is presented by defining the statically stable area for the foot placement. The proposed approach is applied not only to generate the free gait for a quadruped robot walki...
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A new approach to analysis of robot stability is presented by defining the statically stable area for the foot placement. The proposed approach is applied not only to generate the free gait for a quadruped robot walking in difficult terrain, but also to judge the robot stability. The effectiveness of this method is demonstrated by a practical example.
Though generally most of chemical processes are complex multivariable systems with strong interactions, PID controllers are used in most cases even nowadays. However, it is well known that the tuning of their paramete...
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The saturation (output) function is important to cellular neural networks (CNN) because it affects the operation, stable equilibrium points, and the performance of CNN. However, to the best of our knowledge, a systema...
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The saturation (output) function is important to cellular neural networks (CNN) because it affects the operation, stable equilibrium points, and the performance of CNN. However, to the best of our knowledge, a systematic design procedure for the output function is not available in the literature. In this paper, we present a simple, yet effective design method for the tri-output cellular neural network (TCNN). To demonstrate the effectiveness of the output function using our design procedure, we tested TCNN on synthesized images. In addition, we applied the tri-output cellular neural network to the diagnosis of liver diseases and obtained very encouraging results.
Automatic recognition of individuals is a significant problem in the development of pattern recognition. In this paper, we introduce a simple technique for personal identification of human faces in cluttered scenes ba...
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Automatic recognition of individuals is a significant problem in the development of pattern recognition. In this paper, we introduce a simple technique for personal identification of human faces in cluttered scenes based on neural nets. In the detection phase, neural nets are used to test whether a window of 20/spl times/20 pixels contains a face or not. A major difficulty in the learning process comes from the large database required for face/nonface images. We solve this problem by dividing the data into two groups. Such division results in reduction of computational complexity, thus decreasing the time and memory needed during the image test. For the recognition phase, feature measurements are made through Fourier descriptors. Such features are modified to reduce the number of neurons in the hidden layer. Simulation results for the proposed algorithm show good performance compared with previous results.
Automatic recognition of human faces is a significant problem in the development and application of pattern recognition. We introduce a simple technique for identification of human faces in cluttered scenes based on n...
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Automatic recognition of human faces is a significant problem in the development and application of pattern recognition. We introduce a simple technique for identification of human faces in cluttered scenes based on neural nets. In the detection phase, neural nets are used to test whether a window of 20/spl times/20 pixels contains a face or not. A major difficulty in the learning process comes from the large database required for face/nonface images. We solve this problem by dividing these data into two groups. Such a division results in reduction of computational complexity and thus decreasing the time and memory needed during the testing of an image. For the recognition phase, feature measurements are made through Fourier descriptors. Such features are used as input to the neural classifier for training and recognition of ten human faces. Simulation results for the proposed algorithm show a good performance during testing.
This paper proposes an efficient and convenient approach to frequency domain subspace identification for continuous-time systems. In the case of continuous-time models, the data matrices often become ill-conditioned i...
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This paper proposes an efficient and convenient approach to frequency domain subspace identification for continuous-time systems. In the case of continuous-time models, the data matrices often become ill-conditioned if we simply rewrite the Laplace operator s as s = jw where w denotes the frequency. To avoid the ill-conditioned problem, the operator w = ( s - b.α)/( s + b.α) is introduced such that the system can be identified based on a state-space model in the w -operator. And then the estimated w -operator state-space model can be transformed back to the common continuous-time state-space model. An instrumental variable matrix in the frequency domain is also proposed to obtain consistent estimate in the presence of measurement noise.
Sliding mode control is a robust control technique that has been successfully used for the control of linear and nonlinear systems. However, due to the discontinuity in the controller design, the main drawback of slid...
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Sliding mode control is a robust control technique that has been successfully used for the control of linear and nonlinear systems. However, due to the discontinuity in the controller design, the main drawback of sliding mode control is the associated undesirable chattering problem. Although several methods have been developed to reduce control chattering, there isn't any methodology available for the measurement of the chattering strength in the control signal. In this paper, the quantitative measurement of chattering strength is firstly introduced by employing discrete wavelet transform (DWT) in analysing chattering control signal.
In this paper the terminal sliding mode technique is used for solving the finite time output tracking problem for non-minimum phase nonlinear systems. A novel idea of stabilizing zero dynamics of the non-minimum phase...
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In this paper the terminal sliding mode technique is used for solving the finite time output tracking problem for non-minimum phase nonlinear systems. A novel idea of stabilizing zero dynamics of the non-minimum phase system is proposed. The terminal sliding mode control is employed to realize the finite time convergence.
The term hybrid systems designates those physical processes that exhibit both continuous and discrete aspects. On the other hand, some fully continuous systems can benefit from the introduction of an inherently event-...
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The term hybrid systems designates those physical processes that exhibit both continuous and discrete aspects. On the other hand, some fully continuous systems can benefit from the introduction of an inherently event-based system such as an intelligent supervisor thus becoming hybrid themselves. In the present paper, the focus is on this last class of system. More precisely, a new control approach for continuous time systems with unknown high frequency gain sign is presented relying on a logic-driven sliding mode control. Such an approach is compared with a consolidated one based on the so-called Nussbaum function .
This paper presents a survey of current research in the areas of workflow and workflow management systems. We begin by introducing the underlying problems and show how they can be addressed by workflow systems. We rev...
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This paper presents a survey of current research in the areas of workflow and workflow management systems. We begin by introducing the underlying problems and show how they can be addressed by workflow systems. We review and examine the terminology, concepts, methodologies, and problems in the relevant areas. The general requirements of workflow management systems are also introduced and discussed. We present the modelling and specification of both tasks and workflows. We also discuss the dependencies that exist between tasks and how to best define, model and enforce them. An important part of this survey is an examination of key products, including their characteristics and applications. The article is concluded by introducing some research issues which we believe are critical for the advancement of the theory of workflow as well as the design and usage of workflow management systems.
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