A principal component analysis-cerebellar model articulation controller （PCA-CMAC） model is proposed for machine performance degradation assessment.PCA is used to feature selection,which eliminates the redundant inf...A principal component analysis-cerebellar model articulation controller （PCA-CMAC） model is proposed for machine performance degradation assessment.PCA is used to feature selection,which eliminates the redundant information among the features from the sensor signals and reduces the dimension of the input to CMAC.CMAC is used to assess degradation states quantitatively based on its local generalization ability.The implementation of the model is presented and the model is applied in a drilling machine to assess the states of the cutting tool. The results show that the model can assess the wear states quantitatively based on the normal state of the cutting tool.The influence of the quantization parameter g and the generalization parameter r in the CMAC model on the assessment results is analyzed.If g is larger,the generalization ability is better,but the difference of degradation states is not obvious.If r is smaller,the different states are distinct,but memory requirements for storing the weights are larger.The principle for selecting two parameters is that the memory storing the weights should be small while the degradation states should be easily distinguished.展开更多
Claimed as the next generation programming paradigm, mobile agent technology has attracted extensive interests in recent years. However, up to now, limited research efforts have been devoted to the performance study o...Claimed as the next generation programming paradigm, mobile agent technology has attracted extensive interests in recent years. However, up to now, limited research efforts have been devoted to the performance study of mobile agent system and most of these researches focus on agent behavior analysis resulting in that models are hard to apply to mobile agent systems. To bridge the gap, a new performance evaluation model derived from operation mechanisms of mobile agent platforms is proposed. Details are discussed for the design of companion simulation software, which can provide the system performance such as response time of platform to mobile agent. Further investigation is followed on the determination of model parameters. Finally comparison is made between the model-based simulation results and measurement-based real performance of mobile agent systems. The results show that the proposed model and designed software are effective in evaluating performance characteristics of mobile agent systems. The proposed approach can also be considered as the basis of performance analysis for large systems composed of multiple mobile agent platforms.展开更多
A technology for unintended lane departure warning was proposed. As crucial information, lane boundaries were detected based on principal component analysis of grayscale distribution in search bars of given number and...A technology for unintended lane departure warning was proposed. As crucial information, lane boundaries were detected based on principal component analysis of grayscale distribution in search bars of given number and then each search bar was tracked using Kalman filter between frames. The lane detection performance was evaluated and demonstrated in ways of receiver operating characteristic, dice similarity coefficient and real-time performance. For lane departure detection, a lane departure risk evaluation model based on lasting time and frequency was effectively executed on the ARM-based platform. Experimental results indicate that the algorithm generates satisfactory lane detection results under different traffic and lighting conditions, and the proposed warning mechanism sends effective warning signals, avoiding most false warning.展开更多
LRN （low-Reynolds number） modifications to the NR （Norris-Reynolds） k-equation turbulence model are proposed and evaluated. The k and e that render the hybrid time scale are determined using the k-transport equati...LRN （low-Reynolds number） modifications to the NR （Norris-Reynolds） k-equation turbulence model are proposed and evaluated. The k and e that render the hybrid time scale are determined using the k-transport equation together with the Bradshaw and other algebraic relations. The eddy-viscosity coefficient Cμ and the empirical damping function are constructed such as to preserve the anisotropic characteristics of turbulence for application to non-equilibrium turbulent flows. The MNR （modified NR） model is applied to calculate two well-documented flows, yielding predictions in good agreement with the DNS （direct numerical simulation） and experimental data. Comparisons demonstrate that the MNR model offers a significant improvement over the original NR model and competitiveness with the Spalart-Allmaras one-equation turbulence model. The performance evaluation dictates that unlike the original NR model, the MNR model can be employed as a single-equation model instead of associating it with the two-layer model of turbulence.展开更多
The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and ...The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and air conditioning） components in real operation, usually characterized by a wide variation of building loads. In this context, this paper deals with the development and validation of an algorithm aimed at the assessment of part load performance of various kinds of controls for vapour compresion based heat pumps and chillers, in particular referring to on-off, inverter-driven and multi-stage vapour compression. The reliability of this algorithm in the calculation of seasonal performances is checked against monitoring of heat pumps and chillers operating under real conditions.展开更多
The authorS give MLE θ1ML of θ1 in the model Y= θ1+ g(T) +ε, then consider Bahadurasymptotic efficiency of θ1ML, where T and ε are independent, g is unknown, ε￣ (·) is knownwith mean 0 and variance σ2.
基金The National Natural Science Foundation of China(No.60443007,50390063).
文摘A principal component analysis-cerebellar model articulation controller （PCA-CMAC） model is proposed for machine performance degradation assessment.PCA is used to feature selection,which eliminates the redundant information among the features from the sensor signals and reduces the dimension of the input to CMAC.CMAC is used to assess degradation states quantitatively based on its local generalization ability.The implementation of the model is presented and the model is applied in a drilling machine to assess the states of the cutting tool. The results show that the model can assess the wear states quantitatively based on the normal state of the cutting tool.The influence of the quantization parameter g and the generalization parameter r in the CMAC model on the assessment results is analyzed.If g is larger,the generalization ability is better,but the difference of degradation states is not obvious.If r is smaller,the different states are distinct,but memory requirements for storing the weights are larger.The principle for selecting two parameters is that the memory storing the weights should be small while the degradation states should be easily distinguished.
基金Supported by the National Natural Science Foundation of China (No.60072047) and Huawei Science and Technology Foundation (No.YJIN2003004)
文摘Claimed as the next generation programming paradigm, mobile agent technology has attracted extensive interests in recent years. However, up to now, limited research efforts have been devoted to the performance study of mobile agent system and most of these researches focus on agent behavior analysis resulting in that models are hard to apply to mobile agent systems. To bridge the gap, a new performance evaluation model derived from operation mechanisms of mobile agent platforms is proposed. Details are discussed for the design of companion simulation software, which can provide the system performance such as response time of platform to mobile agent. Further investigation is followed on the determination of model parameters. Finally comparison is made between the model-based simulation results and measurement-based real performance of mobile agent systems. The results show that the proposed model and designed software are effective in evaluating performance characteristics of mobile agent systems. The proposed approach can also be considered as the basis of performance analysis for large systems composed of multiple mobile agent platforms.
基金Project(51175159)supported by the National Natural Science Foundation of ChinaProject(2013WK3024)supported by the Science andTechnology Planning Program of Hunan Province,ChinaProject(CX2013B146)supported by the Hunan Provincial InnovationFoundation for Postgraduate,China
文摘A technology for unintended lane departure warning was proposed. As crucial information, lane boundaries were detected based on principal component analysis of grayscale distribution in search bars of given number and then each search bar was tracked using Kalman filter between frames. The lane detection performance was evaluated and demonstrated in ways of receiver operating characteristic, dice similarity coefficient and real-time performance. For lane departure detection, a lane departure risk evaluation model based on lasting time and frequency was effectively executed on the ARM-based platform. Experimental results indicate that the algorithm generates satisfactory lane detection results under different traffic and lighting conditions, and the proposed warning mechanism sends effective warning signals, avoiding most false warning.
文摘LRN （low-Reynolds number） modifications to the NR （Norris-Reynolds） k-equation turbulence model are proposed and evaluated. The k and e that render the hybrid time scale are determined using the k-transport equation together with the Bradshaw and other algebraic relations. The eddy-viscosity coefficient Cμ and the empirical damping function are constructed such as to preserve the anisotropic characteristics of turbulence for application to non-equilibrium turbulent flows. The MNR （modified NR） model is applied to calculate two well-documented flows, yielding predictions in good agreement with the DNS （direct numerical simulation） and experimental data. Comparisons demonstrate that the MNR model offers a significant improvement over the original NR model and competitiveness with the Spalart-Allmaras one-equation turbulence model. The performance evaluation dictates that unlike the original NR model, the MNR model can be employed as a single-equation model instead of associating it with the two-layer model of turbulence.
文摘The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and air conditioning） components in real operation, usually characterized by a wide variation of building loads. In this context, this paper deals with the development and validation of an algorithm aimed at the assessment of part load performance of various kinds of controls for vapour compresion based heat pumps and chillers, in particular referring to on-off, inverter-driven and multi-stage vapour compression. The reliability of this algorithm in the calculation of seasonal performances is checked against monitoring of heat pumps and chillers operating under real conditions.
文摘The authorS give MLE θ1ML of θ1 in the model Y= θ1+ g(T) +ε, then consider Bahadurasymptotic efficiency of θ1ML, where T and ε are independent, g is unknown, ε￣ (·) is knownwith mean 0 and variance σ2.
