GnRH neurons are key elements of the reproductive neuroendocrine system and play important central regulating role in the dynamics of the hormonal cycle. A conductance-based Hodgkin-Huxley model structure is proposed ...
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The presented method for nonlinear system identification is based on the LOLIMOT algorithm introduced by Nelles and Isermann [1996]. The LOLIMOT algorithm divides the input space by a tree-construction algorithm and i...
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The presented method for nonlinear system identification is based on the LOLIMOT algorithm introduced by Nelles and Isermann [1996]. The LOLIMOT algorithm divides the input space by a tree-construction algorithm and interpolates the local linear models by local membership functions. Instead of assuming local linear models, the presented algorithm utilizes general local nonlinear functions, which make the algorithm more flexible. These are approximated by a multidimensional Taylor series. Since the amount of regressors grows fast with the number of inputs and the expansion order, a subset selection procedure is introduced. It reveals significant regressors and gives information about the local functional behavior. The local subset selection is implemented as a stepwise regression with replacement of regressors. Mallows’ C p -statistic is used for the subset selection algorithm and is also implemented for final model selection. The benefit of the extended algorithm lies in the higher flexibility in the local models, which results in less partitions of the input space by a similar approximation quality.
GnRH neurons, as key elements of the reproductive neuroendocrine system, have important central regulating role in the dynamics of the hormonal cycle. A Hodgkin-Huxley type neural model is proposed in this paper, that...
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GnRH neurons, as key elements of the reproductive neuroendocrine system, have important central regulating role in the dynamics of the hormonal cycle. A Hodgkin-Huxley type neural model is proposed in this paper, that takes into account up-to-date biological literature data related to ion channels. The proposed neuron model is highly nonlinear in parameters and the evaluation of the objective function is computationally expensive, therefore the asynchronous parallel pattern search (APPS) procedure has been used for identification. The model with high number of estimated parameters provides a qualitatively good fit of both voltage clamp and current clamp traces.
In this paper, the problem of fault detection is addressed for networked controlsystems (NCSs) subject to both access constraints and random packet dropout, which to the best of our knowledge has not been considered ...
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In this paper, the problem of fault detection is addressed for networked controlsystems (NCSs) subject to both access constraints and random packet dropout, which to the best of our knowledge has not been considered before. Both residual generation and residual evaluation as well as false alarm computation of the designated threshold are given. First, based on a deterministic formulation, residual generation is carried out in the periodic system framework. Then, residual evaluation is achieved by making full use of the stochastic properties of the random packet dropout. Finally, performance evaluation of the designated threshold, i.e., the computation of false alarm rate, is fulfilled with the assistance of Chebyshev s inequality. Simulation results are given to illustrate effectiveness of the proposed method.
In this paper, an adaptive weight particle swarm optimization is proposed for multi-objective optimization. And it is applied to rolling schedules multi-objective optimization of tandem cold rolling. According to the ...
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In this paper, an adaptive weight particle swarm optimization is proposed for multi-objective optimization. And it is applied to rolling schedules multi-objective optimization of tandem cold rolling. According to the demands of actual rolling schedules designing, power distribution, rolling energy consumption and slip rate are selected as objective functions. Then the multi-objective model of rolling schedules is established. The proposed algorithm is applied to rolling schedules optimization of tandem cold rolling. The result shows that the proposed method decreases the values of three objective functions simultaneously compared to actual rolling schedules. Furthermore the proposed algorithm has faster convergence speed than the adaptive weight approach GA.
In this paper, the problem of fault detection is addressed for networked controlsystems (NCSs) subject to both access constraints and random packet dropout, which to the best of our knowledge has not been considered ...
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In this paper, the problem of fault detection is addressed for networked controlsystems (NCSs) subject to both access constraints and random packet dropout, which to the best of our knowledge has not been considered before. Both residual generation and residual evaluation as well as false alarm computation of the designated threshold are given. First, based on a deterministic formulation, residual generation is carried out in the periodic system framework. Then, residual evaluation is achieved by making full use of the stochastic properties of the random packet dropout. Finally, performance evaluation of the designated threshold, i.e., the computation of false alarm rate, is fulfilled with the assistance of Chebyshev s inequality. Simulation results are given to illustrate effectiveness of the proposed method.
This paper presents a model adjustment and a multi-model based fault diagnosis approach. Both methods are based on the same idea. A physical model of the process is altered such that it mimics the behavior of the proc...
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This paper presents a model adjustment and a multi-model based fault diagnosis approach. Both methods are based on the same idea. A physical model of the process is altered such that it mimics the behavior of the process in the presence of certain faults. A number of these modified models, each governing a different fault condition, are evaluated and the model with the smallest output error is determined. As this model is assumed to best govern the current process dynamics, it can be used to diagnose the actual state of the process. Two variations of this idea are presented, tailored specifically to online and offline operation respectively. For online applications, multiple models with fixed parameters are evaluated in parallel, whereas for offline application, an optimization approach is employed. Here, one model with several fault size parameters is regarded and the optimal fault size parameters are determined by means of an interval halving technique. Both techniques have been evaluated at a testbed and have shown very good fault detection and diagnosis capabilities.
In this paper, a fault management system for a hydraulic servo axis is described. This system is capable of sustaining faults in the piston displacement sensor of the position-controlled hydraulic servo axis. By means...
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In this paper, a fault management system for a hydraulic servo axis is described. This system is capable of sustaining faults in the piston displacement sensor of the position-controlled hydraulic servo axis. By means of a parity equation based fault detection stage, faults in the displacement sensor as well as other sensors and components of the servo axis can be detected and subsequently be diagnosed by means of a fuzzy-logic based reasoning system. Upon the diagnosis of a piston displacement sensor fault, the system switches to a “model-sensor” which provides an estimate for the piston position. To ensure the utmost model fidelity of the model sensor, the model parameters are constantly updated by means of parameter estimation during the fault-free operation of the servo axis. Experiments at a hydraulic servo axis conclude this paper and show the high quality of the reconstructed piston displacement sensor signal.
In this paper, a Takagi-Sugeno (T-S) fuzzy model-based method is proposed to deal with the problem of synchronization of two identical or different hyperchaotic systems. The T-S fuzzy models with a small number of fuz...
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This paper presents the results of the parameter estimation procedure for the primary circuit dynamics of a VVER-type nuclear power plant. The model structure is a low dimensional lumped nonlinear model published prev...
This paper presents the results of the parameter estimation procedure for the primary circuit dynamics of a VVER-type nuclear power plant. The model structure is a low dimensional lumped nonlinear model published previously in Fazekas et al. [2007a]. The parameter estimation method uses the modular decomposition of the system model for obtaining physically meaningful initial parameter estimates. The final parameter estimates are computed using the integrated model.
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