Proposes a texture modelling method based on the pattern spectrum. The pattern spectrum is a mathematical morphological method to describe the size distribution of objects contained in an image. Our method is based on...
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(纸本)0769507506
Proposes a texture modelling method based on the pattern spectrum. The pattern spectrum is a mathematical morphological method to describe the size distribution of objects contained in an image. Our method is based on the idea of obtaining a model of the elementary particles that form a texture by optimizing a gray scale structuring element to fit the shape of elementary particles. The optimization method is applied in two stages: the first stage optimizes the extent of the structuring element and the second optimizes the pixel values in the extent.
In a number of array signal processing applications, such as underwater source localization, the propagation medium is not homogeneous, which causes a distortion of the wavefront received by the array. In this paper, ...
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In a number of array signal processing applications, such as underwater source localization, the propagation medium is not homogeneous, which causes a distortion of the wavefront received by the array. In this paper, we consider the direction-of-arrival (DOA) estimation problem for such distorted wavefronts. In previous approaches, the so-called multiplicative noise scenario is considered based on the assumption that the distortion is random and can be parameterized by a small number of parameters. To gain robustness against mismodelling we assume a scenario in which the wavefront amplitude is distorted in a completely arbitrary way. We derive the maximum likelihood (ML) estimator of the DOA and show it can be obtained by means of a simple 1D search. The Cramer-Rao bound (CRB) for the problem at hand is derived. Numerical simulations illustrate a good performance of the estimator and show that its accuracy is comparable with that of estimators which require knowledge of the form of amplitude distortions.
Vibration isolation control system design for a microgravity experiment mount is considered. The controller design based on dynamic sliding manifold (DSM) technique is proposed to attenuate the accelerations transmitt...
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Vibration isolation control system design for a microgravity experiment mount is considered. The controller design based on dynamic sliding manifold (DSM) technique is proposed to attenuate the accelerations transmitted to an isolated experiment mount either from a vibrating base or directly generated by the experiment, as well as to stabilize the internal dynamics of this nonminimum phase plant. An auxiliary DSM is employed to maintain the asymptotic high-order sliding mode on the primary sliding manifold in the presence of uncertain actuator dynamics of the second order. The primary DSM is designed for the closed-loop.
A problem of sliding mode control design for a SISO system with unmodeled actuators of the first and second order is considered. A design methodology, based on dynamic sliding manifolds (DSM), is proposed to attenuate...
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A problem of sliding mode control design for a SISO system with unmodeled actuators of the first and second order is considered. A design methodology, based on dynamic sliding manifolds (DSM), is proposed to attenuate the chattering phenomenon affecting sliding-mode-controlled plants in the presence of unmodeled dynamics. The proposed methodology maintains the sliding mode on the sliding surface, which is designed without actuator dynamics being considered. This goal is achieved via auxiliary dynamic sliding manifold design; the sliding mode on the auxiliary DSM provides for high order asymptotic sliding mode on the initial surface.
Linear repetitive processes are a distinct class of 2D linear systems of both theoretical and practical interest. The stability theory for these processes currently consists of two distinct concepts termed asymptotic ...
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Linear repetitive processes are a distinct class of 2D linear systems of both theoretical and practical interest. The stability theory for these processes currently consists of two distinct concepts termed asymptotic stability and stability along the pass respectively where the former is a necessary condition for the latter. Recently applications have arisen where asymptotic stability is too weak and stability along the pass is too strong for meaningful progress to be made. This paper develops the concept of strong practical stability for such cases.
Combining position and force control is highly desirable in many robot applications. Many years of extensive research has resulted in a number of promising control approaches, but often too much engineering effort is ...
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Combining position and force control is highly desirable in many robot applications. Many years of extensive research has resulted in a number of promising control approaches, but often too much engineering effort is required in order to evaluate a low level (high performance) control scheme on a real manipulator. The new control system we have obtained has two main advantages: first it provides a total open control architecture, and second it is the simplicity and the interactivity of the platform developed. Using this new control architecture, any force and motion control strategy can be programmed and implemented in a graphical and easy way.
Tuning rules for PI and PID controllers for stable non oscillating plants are presented in this paper. These rules are based on an optimization procedure, where both low frequency performance, mid frequency stability ...
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Tuning rules for PI and PID controllers for stable non oscillating plants are presented in this paper. These rules are based on an optimization procedure, where both low frequency performance, mid frequency stability margins and high frequency control activity are taken into account. The required plant knowledge is typically the phase crossover frequency of the plant and the corresponding gain at this frequency, like in Ziegler Nichols frequency design method. Near optimal tuning rules are presented based on this knowledge and the plant low frequency gain, both for PI and PID controllers. Related results are also given for plants with very high or no phase crossover frequency at all.
This paper is concerned with the problem of H ∞ filtering for linear continuous-time systems with uncertain time-varying parameters in the matrices of the state-space signal model. The admissible values of the parame...
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This paper is concerned with the problem of H ∞ filtering for linear continuous-time systems with uncertain time-varying parameters in the matrices of the state-space signal model. The admissible values of the parameters and their rates of variation are assumed to belong to a given polyhedral region. Based on a parameter-dependent Lyapunov function, which is quadratic in the uncertain parameters, we develop an LMI method for designing a linear stationary, asymptotically stable filter, which ensures a prescribed performance in a H ∞ sense.
The C4ISR Architecture Framework document issued by the Department of Defense specifies three views of an information architecture and defines a set of products that describe each view. These architecture views are to...
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