One of the expected benefits of wavelength division multiplexing (WDM) is the possibility to provide an optical layer (OL) with built-in capabilities to survive network component faults, e.g., fiber cut. Several schem...
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ISBN:
(纸本)0780367111
One of the expected benefits of wavelength division multiplexing (WDM) is the possibility to provide an optical layer (OL) with built-in capabilities to survive network component faults, e.g., fiber cut. Several schemes exist to design a reliable OL. These schemes are generally divided into protection and restoration techniques. Protection schemes reserve in advance a dedicated backup path and a wavelength that are readily available upon disruption of the working path. Restoration schemes, on the contrary, dynamically look for backup paths of spare wavelengths upon failure occurrence. The authors propose a fast and efficient path restoration scheme called preplanned weighted restoration (PWR). In the PWR scheme distinct restoration paths are precomputed at the source node during the connection setup. Upon failure, one of the preplanned paths is randomly selected depending on specific weights precalculated by the source node. The proposed scheme requires limited signaling upon failure occurrence as coordination among the source nodes involved in the restoration process is not required. Therefore, the scheme is fast and scalable in terms of number of network nodes, link or fiber capacity, and number of connections. Yet, the presented results show that the PWR scheme may considerably decrease the blocking probability of the restoration attempts when compared to other schemes such as alternate routing.
This paper presents a new multi-rate estimator design for multi-rate output feedback control (MROFC) using the current state estimator. It is shown that the principle of separation works in the design of MROFC. The MR...
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This paper presents a new multi-rate estimator design for multi-rate output feedback control (MROFC) using the current state estimator. It is shown that the principle of separation works in the design of MROFC. The MROFC system is shown to be less sensitive to noise disturbances than the single-rate control system. The proposed MROFC is applied to a galvanometer servo system. Simulation and experimental results show improved settling and tracking performance over the conventional single-rate control.
computer networks are pervasive and critical to the operation of today's businesses. While most of us take computer networks for granted, network managers who must configure, operate, and fix faults in computer ne...
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computer networks are pervasive and critical to the operation of today's businesses. While most of us take computer networks for granted, network managers who must configure, operate, and fix faults in computer networks face a daunting task that becomes more complex everyday. Ecological interface design has been shown to be a promising approach for complex systems such as power plants or petrochemical systems. computer networks are a very different work domain characterized by rapid technological change, extreme decentralization, and the existence of "soft" components. This paper presents the first work domain analysis of this new domain creating an abstraction hierarchy for general signal transfer systems and general computing networks. It shows how the abstraction hierarchy can be applied to this new domain and presents the initial work on an ecological interface design for network management.
This paper reports the development of a new miniature force sensor to measure forces at the tip of a microsurgical instrument in three dimensions with sub-millinewton resolution. This sensor will enable enhanced force...
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computer networks are pervasive and critical to the operation of today's businesses. While most of us take computer networks for granted, network managers who must configure, operate, and fix faults in computer ne...
computer networks are pervasive and critical to the operation of today's businesses. While most of us take computer networks for granted, network managers who must configure, operate, and fix faults in computer networks face a daunting task that becomes more complex everyday. Ecological interface design has been shown to be a promising approach for complex systems such as power plants or petrochemical systems. computer networks are a very different work domain characterized by rapid technological change, extreme decentralization, and the existence of “soft” components. This paper presents the first work domain analysis of this new domain creating an abstraction hierarchy for general signal transfer systems and general computing networks. It shows how the abstraction hierarchy can be applied to this new domain and presents the initial work on an ecological interface design for network management.
This paper present a new effective algorithm for the optimal realization of state estimate feedback controller structures for discrete time systems subject to finite-word-length constraints. The problem is formulated ...
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Considers a physical system described by a set of parameters. Each parameter is either measured by a number of sensors or estimated by a set of computer programs that use sensor measurements. As a result, the resultan...
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Considers a physical system described by a set of parameters. Each parameter is either measured by a number of sensors or estimated by a set of computer programs that use sensor measurements. As a result, the resultant parameter values could be widely varying. We propose a fusion method that combines the measurements and estimators based on the physical laws that relate the parameters. In comparison with the traditional fusion problems, there is no training set that provides the actual parameter values. Furthermore, since every parameter is measured or estimated, there are no parameters whose actual values are known. We propose a fuser based on the least violation of the physical laws that relate the parameters. Under certain smoothness conditions on the physical law, we show the asymptotic convergence of our method, and also derive distribution-free performance bounds based on finite samples. We illustrate the effectiveness of this method for a practical problem of fusing well-log data in methane hydrate exploration. For this problem, the data fusion method resulted in an order-of-magnitude improvement in the accuracy compared to the best set of estimators for the key parameter of porosity.
In this paper, limit cycles and chaotic motion of a single-link robot manipulator moving at low speed are investigated. The dynamic model of the one-link robot manipulator is set up in which different joint friction i...
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In this paper, limit cycles and chaotic motion of a single-link robot manipulator moving at low speed are investigated. The dynamic model of the one-link robot manipulator is set up in which different joint friction is considered. By using the describing function of the nonlinear part of the robot control system, stable limit cycles are proven to exist. The chaotic motion is shown via a Poincare map. Numerical simulations identify the chaotic zone location near the imaginary axis of the complex plane.
A neural network approach to real-time trajectory generation with clearance from obstacles in a nonstationary environment is proposed based on a biologically inspired model for a mobile robot. It is also extended to m...
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A neural network approach to real-time trajectory generation with clearance from obstacles in a nonstationary environment is proposed based on a biologically inspired model for a mobile robot. It is also extended to multi-joint robot manipulators. The strength of obstacle clearance is adjustable. The optimal trajectory is generated by implicitly minimising the robot travel distance while considering the obstacle clearance. The generated real-time “comfortable” path does not suffer from the “too close” or the “too far” problems. The stability is guaranteed by Lyapunov stability analysis. The effectiveness and the efficiency are demonstrated through simulation and comparison studies.
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