In order to obtain accurate prediction model and compensate for the influence of model mismatch on the control performance of the system and avoid solving nonlinear programming problem,an adaptive fuzzy predictive fun...In order to obtain accurate prediction model and compensate for the influence of model mismatch on the control performance of the system and avoid solving nonlinear programming problem,an adaptive fuzzy predictive functional control(AFPFC) scheme for multivariable nonlinear systems was proposed.Firstly,multivariable nonlinear systems were described based on Takagi-Sugeno(T-S) fuzzy models;assuming that the antecedent parameters of T-S models were kept,the consequent parameters were identified on-line by using the weighted recursive least square(WRLS) method.Secondly,the identified T-S models were linearized to be time-varying state space model at each sampling instant.Finally,by using linear predictive control technique the analysis solution of the optimal control law of AFPFC was established.The application results for pH neutralization process show that the absolute error between the identified T-S model output and the process output is smaller than 0.015;the tracking ability of the proposed AFPFC is superior to that of non-AFPFC(NAFPFC) for pH process without disturbances,the overshoot of the effluent pH value of AFPFC with disturbances is decreased by 50% compared with that of NAFPFC;when the process parameters of AFPFC vary with time the integrated absolute error(IAE) performance index still retains to be less than 200 compared with that of NAFPFC.展开更多
A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the ...A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.展开更多
In view of the fact that climate-related disasters are already taking a heavy toll, causing massive damage to crops and infrastructure and forcing some people to flee their homes, however, the potential impacts of cli...In view of the fact that climate-related disasters are already taking a heavy toll, causing massive damage to crops and infrastructure and forcing some people to flee their homes, however, the potential impacts of climate change are likely to trigger adaptive responses that influence environmental and socio-economic drivers of food system performance in positive as well as negative ways. This paper was conducted through the collection of some research materials with the projected balance of these various climate impacts on food system performance and food security outcomes at the local and global levels. More so that, food security is likely to be affected by climate change in several ways： food security depends not only on the direct impact of climate change on food production but also on its indirect impact on human nutrition and health, economic growth, trade flows and food aid policy. The paper further examined the effectiveness of managing new risks and uncertainty, improving the quality of information and its use, monitoring weather and improving scientific understanding of climate change, promoting insurance schemes, maintaining biodiversity and access to fund as some of the crucial measures for adaptation. The large amount of resources that would be necessary to avoid the worst case scenario suggests the necessity of continued support from the international community to improve food security at the local and global levels as a whole.展开更多
基金Project(2007AA04Z162) supported by the National High-Tech Research and Development Program of ChinaProjects(2006T089, 2009T062) supported by the University Innovation Team in the Educational Department of Liaoning Province, China
文摘In order to obtain accurate prediction model and compensate for the influence of model mismatch on the control performance of the system and avoid solving nonlinear programming problem,an adaptive fuzzy predictive functional control(AFPFC) scheme for multivariable nonlinear systems was proposed.Firstly,multivariable nonlinear systems were described based on Takagi-Sugeno(T-S) fuzzy models;assuming that the antecedent parameters of T-S models were kept,the consequent parameters were identified on-line by using the weighted recursive least square(WRLS) method.Secondly,the identified T-S models were linearized to be time-varying state space model at each sampling instant.Finally,by using linear predictive control technique the analysis solution of the optimal control law of AFPFC was established.The application results for pH neutralization process show that the absolute error between the identified T-S model output and the process output is smaller than 0.015;the tracking ability of the proposed AFPFC is superior to that of non-AFPFC(NAFPFC) for pH process without disturbances,the overshoot of the effluent pH value of AFPFC with disturbances is decreased by 50% compared with that of NAFPFC;when the process parameters of AFPFC vary with time the integrated absolute error(IAE) performance index still retains to be less than 200 compared with that of NAFPFC.
基金Project(2010-0020163)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education
文摘A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.
文摘In view of the fact that climate-related disasters are already taking a heavy toll, causing massive damage to crops and infrastructure and forcing some people to flee their homes, however, the potential impacts of climate change are likely to trigger adaptive responses that influence environmental and socio-economic drivers of food system performance in positive as well as negative ways. This paper was conducted through the collection of some research materials with the projected balance of these various climate impacts on food system performance and food security outcomes at the local and global levels. More so that, food security is likely to be affected by climate change in several ways： food security depends not only on the direct impact of climate change on food production but also on its indirect impact on human nutrition and health, economic growth, trade flows and food aid policy. The paper further examined the effectiveness of managing new risks and uncertainty, improving the quality of information and its use, monitoring weather and improving scientific understanding of climate change, promoting insurance schemes, maintaining biodiversity and access to fund as some of the crucial measures for adaptation. The large amount of resources that would be necessary to avoid the worst case scenario suggests the necessity of continued support from the international community to improve food security at the local and global levels as a whole.
