The linear systems affected by additive external sinusoidal disturbances is studied. The problem is to damp this forced oscillation in an optimal fashion. The main result of this paper is a new design approach is prop...The linear systems affected by additive external sinusoidal disturbances is studied. The problem is to damp this forced oscillation in an optimal fashion. The main result of this paper is a new design approach is proposed of realizable feedforward and feedback optimal control law for a linear time invariant system with sinusoidal disturbances. The algorithm of solving the optimal control law is given. It is shown that the control law is easily realized and is robust with respect to errors produced by the external sinusoidal disturbances through simulation results.展开更多
The optimal control problem was studied for linear time-varying systems,which was affected by external persistent disturbances with known dynamic characteristics but unknown initial conditions. To damp the effect of d...The optimal control problem was studied for linear time-varying systems,which was affected by external persistent disturbances with known dynamic characteristics but unknown initial conditions. To damp the effect of disturbances in an optimal fashion,we obtained a new feedforward and feedback optimal control law and gave the control algorithm by solving a Riccati differential equation and a matrix differential equation. Simulation results showed that the achieved optimal control law was realizable,efficient and robust to reject the external disturbances.展开更多
Introduction ’Shakespeare’ as a course is taught to three different kinds of students in Sichuan University. First, as a degree course for English Major (Literature) postgraduates. Second, as a required course for E...Introduction ’Shakespeare’ as a course is taught to three different kinds of students in Sichuan University. First, as a degree course for English Major (Literature) postgraduates. Second, as a required course for English Major (Linguistics) postgraduates and third, as an optional course for fourth-year undergraduates. As their focus point is different, the teacher must meet these different needs by designing different courses, even preparing different materials and different examinations, while keeping a common core.展开更多
Background:It is well known that the pulvinar establishes reciprocal connections with areas of the visual cortex,allowing the transfer of cortico-cortical signals through transthalamic pathways.However,the exact funct...Background:It is well known that the pulvinar establishes reciprocal connections with areas of the visual cortex,allowing the transfer of cortico-cortical signals through transthalamic pathways.However,the exact function of these signals in coordinating activity across the visual cortical hierarchy remains largely unknown.In anesthetized cats,we have explored whether pulvinar inactivation affects the dynamic of interactions between the primary visual cortex(a17)and area 21a,a higher visual cortical area,as well as between layers within each cortical area.We found that pulvinar inactivation modifies the local field potentials(LFPs)coherence between a17 and 21a during a visual stimulation.In addition,the Granger causality analysis showed that the functional connectivity changed across visual areas and between cortical layers during pulvinar inactivation,the effects being stronger in layers of the same area.We observed that the effects of pulvinar inactivation arise at two different epochs of the visual response,i.e.,at the early and late components.The proportion of feedback and feedforward functional events was higher during the early and the late phases of the responses,respectively.We also found that pulvinar inactivation facilitates the feedback propagation of gamma oscillations from 21a to a17.This feedback transmission was predominant during the late response.At the temporal level,pulvinar inactivation also delayed the signals from a17 and 21a,depending on the source and the target of the cortical layer.Thus,the pulvinar can not only modify the functional connectivity between intra and inter cortical layers but may also control the temporal dynamics of neuronal activity across the visual cortical hierarchy.Methods:In vivo electrophysiological recordings of visual cortical areas,area 17 and 21a,in anesthetized cats,were then explored with temporal serial analysis(i.e.,Fourier analysis,Coherence,Cross-correlation and Granger causality)of the local field potential.Results:Inactivation of the thalamic nucleus modifies the dynamics of areas 17 and 21a.The changes observed depends on the source and the target of the cortical layer.The pulvinar inactivation arise at two different epochs of visual response.Conclusions:The pulvinar modifies the functional connectivity between intra and inter cortical layers and may also control the temporal dynamics of neuronal activity across the visual cortical hierarchy.展开更多
文摘The linear systems affected by additive external sinusoidal disturbances is studied. The problem is to damp this forced oscillation in an optimal fashion. The main result of this paper is a new design approach is proposed of realizable feedforward and feedback optimal control law for a linear time invariant system with sinusoidal disturbances. The algorithm of solving the optimal control law is given. It is shown that the control law is easily realized and is robust with respect to errors produced by the external sinusoidal disturbances through simulation results.
基金the National Natural Science Foundation of China (Grant No.60074001)the Natural Science Foundation of Shandong Province (Grant No.Y2000G02).
文摘The optimal control problem was studied for linear time-varying systems,which was affected by external persistent disturbances with known dynamic characteristics but unknown initial conditions. To damp the effect of disturbances in an optimal fashion,we obtained a new feedforward and feedback optimal control law and gave the control algorithm by solving a Riccati differential equation and a matrix differential equation. Simulation results showed that the achieved optimal control law was realizable,efficient and robust to reject the external disturbances.
文摘Introduction ’Shakespeare’ as a course is taught to three different kinds of students in Sichuan University. First, as a degree course for English Major (Literature) postgraduates. Second, as a required course for English Major (Linguistics) postgraduates and third, as an optional course for fourth-year undergraduates. As their focus point is different, the teacher must meet these different needs by designing different courses, even preparing different materials and different examinations, while keeping a common core.
文摘Background:It is well known that the pulvinar establishes reciprocal connections with areas of the visual cortex,allowing the transfer of cortico-cortical signals through transthalamic pathways.However,the exact function of these signals in coordinating activity across the visual cortical hierarchy remains largely unknown.In anesthetized cats,we have explored whether pulvinar inactivation affects the dynamic of interactions between the primary visual cortex(a17)and area 21a,a higher visual cortical area,as well as between layers within each cortical area.We found that pulvinar inactivation modifies the local field potentials(LFPs)coherence between a17 and 21a during a visual stimulation.In addition,the Granger causality analysis showed that the functional connectivity changed across visual areas and between cortical layers during pulvinar inactivation,the effects being stronger in layers of the same area.We observed that the effects of pulvinar inactivation arise at two different epochs of the visual response,i.e.,at the early and late components.The proportion of feedback and feedforward functional events was higher during the early and the late phases of the responses,respectively.We also found that pulvinar inactivation facilitates the feedback propagation of gamma oscillations from 21a to a17.This feedback transmission was predominant during the late response.At the temporal level,pulvinar inactivation also delayed the signals from a17 and 21a,depending on the source and the target of the cortical layer.Thus,the pulvinar can not only modify the functional connectivity between intra and inter cortical layers but may also control the temporal dynamics of neuronal activity across the visual cortical hierarchy.Methods:In vivo electrophysiological recordings of visual cortical areas,area 17 and 21a,in anesthetized cats,were then explored with temporal serial analysis(i.e.,Fourier analysis,Coherence,Cross-correlation and Granger causality)of the local field potential.Results:Inactivation of the thalamic nucleus modifies the dynamics of areas 17 and 21a.The changes observed depends on the source and the target of the cortical layer.The pulvinar inactivation arise at two different epochs of visual response.Conclusions:The pulvinar modifies the functional connectivity between intra and inter cortical layers and may also control the temporal dynamics of neuronal activity across the visual cortical hierarchy.
