A piece-wise second order approximation to the f (x) = - log [tanh (x/2)] function is proposed to reduce the computational complexity of LDPC decoder's utilizing Loy-Likelihood Ratio Belief Propagation (LLR-BP) al...
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A piece-wise second order approximation to the f (x) = - log [tanh (x/2)] function is proposed to reduce the computational complexity of LDPC decoder's utilizing Loy-Likelihood Ratio Belief Propagation (LLR-BP) algorithm based on Gallager's approach. Simulation results show that the proposed low complexity approximation doesn't cause BER performance degradation.
The problems of predicting intermetallic compounds not yet synthesized are discussed. It is noted that the use of classical physicochemical analysis in the study of multicomponent metallic systems is associated with t...
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The problems of predicting intermetallic compounds not yet synthesized are discussed. It is noted that the use of classical physicochemical analysis in the study of multicomponent metallic systems is associated with the complexity of presenting multidimensional phase diagrams. The use of modern information technology with application of computer pattern recognition method is a route to the prediction new intermetallics with specified properties. The algorithms used most often in these methods are briefly considered and the efficiency of their use for predicting new compounds is demonstrated. The bibliography includes 144 references.
Work has been underway at the CSM on the development of autonomous (tele-managed) LHD mining machines. Previous work has shown that ultrasonic sensors exhibit several characteristics which make them a reasonable choic...
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Work has been underway at the CSM on the development of autonomous (tele-managed) LHD mining machines. Previous work has shown that ultrasonic sensors exhibit several characteristics which make them a reasonable choice for sensor based navigation in underground mining operations. This paper discusses recent work done to (1) develop control algorithms for use with these sensors, (2) experiments with a scale model of an LHD to verify the ultrasonic based control and modeling methods, and (3) approaches to developing real-time task level control models.
In this paper we present an incremental diagnostic engine: IMBDE. IMBDE utilises qualitative models, and combines an extended version of Nayak and Williams' ITMS (based on root antecedents) with an incremental ver...
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In this paper we present an incremental diagnostic engine: IMBDE. IMBDE utilises qualitative models, and combines an extended version of Nayak and Williams' ITMS (based on root antecedents) with an incremental version of Reiter's Hitting Set Algorithm to perform incremental state based diagnosis on dynamic process systems. The approach is demonstrated to work by application to an industrial process - an ammonia washer system. (C) 2009 Elsevier Ltd. All rights reserved.
An algorithm utilising direct feedbacks of torque and reactive power for the control of a doubly fed induction generator (DFIG) is proposed. Although the algorithm is based on field-oriented control, the algorithm cal...
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An algorithm utilising direct feedbacks of torque and reactive power for the control of a doubly fed induction generator (DFIG) is proposed. Although the algorithm is based on field-oriented control, the algorithm calculates the feedback and feed-forward variables in the stator reference frame to reduce the number of coordinate transformations. Since the algorithm uses a single-loop approach instead of a cascaded loop design, the tuning of the controller is easier and the response time is faster when compared to those of most existing methods. The internal model control (IMC) design method is used in the proposed scheme to formulate the controller parameters. Measures on the possible voltage variations are included to increase the robustness of the system. computer simulation and experimental implementation are reported. The results show that the algorithm can control the torque and reactive power independently. Harmonic distortions generated by the system are not noticeable because of the use of constant switching frequency.
Spread-Doppler clutter caused by multi-mode propagation seriously affects the over-the-horizon radar detection performance for slow ships. To solve this problem, the authors propose to suppress multi-mode clutter usin...
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Spread-Doppler clutter caused by multi-mode propagation seriously affects the over-the-horizon radar detection performance for slow ships. To solve this problem, the authors propose to suppress multi-mode clutter using spatial information in the multiple-input-multiple-output over-the-horizon radar system. Traditional processing algorithms need prior information of the target direction. However, it is often not readily available. In this study, they propose a novel multi-mode clutter suppression algorithm based on the second-order blind identification (SOBI) technique. The proposed algorithm does not need prior information of the target direction and can effectively suppress the multi-mode clutter. Considering that the SOBI algorithm affected by the similarity in sources spectra, they improve the proposed algorithm using the spatial smoothing technique. Simulation results show that, in the single target scene, the improved algorithm can effectively eliminate the spectrum burrs caused by incomplete separation, making separated signals smoother. Signal-to-clutter-noise ratio is greatly improved. The good multi-mode clutter suppression performance is obtained. In the multi-mode scenario that double targets with the same radial velocity, that is, sources spectra have similarities, the algorithm based on SOBI cannot separate all targets. Although the improved algorithm can make all targets visible and effectively suppresses the multi-mode clutter.
This paper is concerned with the problem of multitarget coverage based on probabilistic detection model. Coverage configuration is an effective method to alleviate the energy-limitation problem of sensors. Firstly, co...
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This paper is concerned with the problem of multitarget coverage based on probabilistic detection model. Coverage configuration is an effective method to alleviate the energy-limitation problem of sensors. Firstly, considering the attenuation of node's sensing ability, the target probabilistic coverage problem is defined and formalized, which is based on Neyman-Peason probabilistic detection model. Secondly, in order to turn off redundant sensors, a simplified judging rule is derived, which makes the probabilistic coverage judgment execute on each node locally. Thirdly, a distributed node schedule scheme is proposed for implementing the distributed algorithm. Simulation results show that this algorithm is robust to the change of network size, and when compared with the physical coverage algorithm, it can effectively minimize the number of active sensors, which guarantees all the targets gamma-covered.
Based on an analysis of the capability operators of the Calculus of Mobile Ambients, three fairness principles are proposed to safeguard the interactions of the ambients. The Calculus of Fair Ambient is designed to me...
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Based on an analysis of the capability operators of the Calculus of Mobile Ambients, three fairness principles are proposed to safeguard the interactions of the ambients. The Calculus of Fair Ambient is designed to meet these fairness principles. A labeled transition semantics for the calculus is defined to support structural investigation. The bisimulation theory of the fair ambients is studied and two coincidence results are established. An expressiveness result of the calculus is formally established by proving that it contains the pi calculus as a sub-calculus.
A method is proposed to retrieve mathematical formula in LaTeX documents. Firstly, we represent the retrieved mathematical formula by binary tree according to its LaTeX description, normalize the structure of the bina...
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A method is proposed to retrieve mathematical formula in LaTeX documents. Firstly, we represent the retrieved mathematical formula by binary tree according to its LaTeX description, normalize the structure of the binary tree, and obtain the structure code and then search the mathematical formula table that is named by the structure code and the formula elements of the first two levels of the binary tree in the mathematical formula database. If the table exists, then we search the normalizing variable name preorder traversing sequence of the binary tree in the table and display the document information that contain the mathematical formula. The experimental results show that the algorithm realizes the retrieval of mathematical formula in LaTeX documents and has higher retrieval precision and faster retrieval speed.
A control algorithm is presented for a hexapod walking machine, with alternating tripod-gait, proceeding over soft ground. The control algorithm is based on a foot-force sensing and is composed of two parts. The first...
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A control algorithm is presented for a hexapod walking machine, with alternating tripod-gait, proceeding over soft ground. The control algorithm is based on a foot-force sensing and is composed of two parts. The first part, which is applied to the leg alternating phase, confirms the support of body weight and generates the ground model using internal sensors. The second, which is applied to the body-propelling phase, compensates for the additional ground-sinkage due to the change of supporting force using the generated ground model. The proposed control algorithm is incorporated into the hexapod walking machine (MELWALK-III) and some basic experiments are performed to demonstrate the effectiveness of the algorithm for three types of ground simulations.
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