Active tendon, consisting of a displacement actuator and a collocated force sensor, was first presented by Preumont and his co-workers to attenuate the vibration of large flexible space structures, and the control alg...Active tendon, consisting of a displacement actuator and a collocated force sensor, was first presented by Preumont and his co-workers to attenuate the vibration of large flexible space structures, and the control algorithm adopted by them was integral force feedback. This paper presents a new proportional-integral （PI） force feedback algorithm to achieve larger damping ratios for the structure without the requirement of structure model. Stability of the control system is shown, and simulations of a structure similar to JPL-MPI demonstrate the effectiveness of the proposed algorithm for vibration control of space structures.展开更多
The attraction domains of memory patterns and exponential convergence rate of the network trajectories to memory patterns for continuous feedback associative memory are estimated. These results can be used for evaluat...The attraction domains of memory patterns and exponential convergence rate of the network trajectories to memory patterns for continuous feedback associative memory are estimated. These results can be used for evaluation of error-correction capability and the synthesis procedures for continuous-time associative memory neural networks.展开更多
For an open quantum system containing two qubits under homodyne-based feedback control,we investigate the dynamical behaviors of quantum-memory-assisted entropic uncertainty.Moreover,we analyze the influence of feedba...For an open quantum system containing two qubits under homodyne-based feedback control,we investigate the dynamical behaviors of quantum-memory-assisted entropic uncertainty.Moreover,we analyze the influence of feedback modes and coefficients on the entropic uncertainty.Numerical investigations show that the memory qubit should be placed in a non-dissipative channel if the single dissipative channel condition can be chosen,which helps reduce the entropic uncertainty of the system.For the homodyne feedback control F=λσx(or F=λσy),due to different roles of the entangled qubits A and B,when they are subject to feedback control with different feedback coefficientsλ,the exchange of feedback coefficients will cause variations of the entropic uncertainty.When the feedback coefficient corresponding to the memory qubit B is larger(λB>λA),the steady value of the entropic uncertainty will be small,which is conducive to enhancing the robustness of the system.However,for the feedback control F=λσz,the difference between the feedback coefficients has no effect on the steady values of the entropic uncertainty.展开更多
The present work primarily aims to explore the neuronal calcium(Ca^(2+)),IP_(3),and dopamine(DA)signaling systems through a feedback loop model.To date,there has been no exploration of this feedback model in fractiona...The present work primarily aims to explore the neuronal calcium(Ca^(2+)),IP_(3),and dopamine(DA)signaling systems through a feedback loop model.To date,there has been no exploration of this feedback model in fractional-order dynamical systems.This feedback loop model incorporates several crucial mechanisms like the buffering process,IP_(3)-receptor,ryanodine receptor,plasma membrane Ca^(2+)ATPase and sarcoplasmic/endoplasmic reticulum calcium ATPase(SERCA)pump,leak,sodium-calcium exchanger,voltage-gated Ca^(2+)channel,Orai channels,DA-dependent IP_(3)synthesis,and others.By incorporating these mechanisms,the model aims to provide a more comprehensive and realistic understanding of the system under investigation.The present model incorporates fractional-order dynamics along both spatial and temporal dimensions to examine the impacts of superdiffusion and memory showing Brownian motion of Ca^(2+),IP_(3),and DA signaling molecules.The bidirectional feedback between calcium and IP_(3)signaling systems,unidirectional feedback between calcium and dopamine signaling systems,and unidirectional feedback between IP_(3)and dopamine signaling systems have been incorporated into the present model.These feedback loops establish interactions among calcium,IP_(3),and dopamine signaling systems within neuronal cells.The numerical findings were obtained by using the Crank-Nicholson method with the Grunwald technique for fractional space derivatives and the L1method for fractional time derivatives in conjunction with the Gauss-Seidel Iterations.This research specifically investigates the implications of cell memory as well as superdiffusion on Ca^(2+),IP_(3),and DA dynamics in neuronal cells,which are interactive nonlinear systems.The superdiffusion process results in a reduction in Ca^(2+),IP_(3),and DA concentrations,while cellular memory leads to an increase in ion and molecule concentrations in neuronal cells during the initial time.The disruption of any given process can lead to imbalances in calcium,IP_(3),and DA systems,hence contributing to neurotoxicity and cellular demise.展开更多
基金the National Natural Science Foundation of China (10572070)Tsinghua Basic Research Foundation (JCqn2005029)
文摘Active tendon, consisting of a displacement actuator and a collocated force sensor, was first presented by Preumont and his co-workers to attenuate the vibration of large flexible space structures, and the control algorithm adopted by them was integral force feedback. This paper presents a new proportional-integral （PI） force feedback algorithm to achieve larger damping ratios for the structure without the requirement of structure model. Stability of the control system is shown, and simulations of a structure similar to JPL-MPI demonstrate the effectiveness of the proposed algorithm for vibration control of space structures.
基金Supported by the National Natural Science Foundation of Chinathe Climb Project of China
文摘The attraction domains of memory patterns and exponential convergence rate of the network trajectories to memory patterns for continuous feedback associative memory are estimated. These results can be used for evaluation of error-correction capability and the synthesis procedures for continuous-time associative memory neural networks.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61663016 and 11404150)
文摘For an open quantum system containing two qubits under homodyne-based feedback control,we investigate the dynamical behaviors of quantum-memory-assisted entropic uncertainty.Moreover,we analyze the influence of feedback modes and coefficients on the entropic uncertainty.Numerical investigations show that the memory qubit should be placed in a non-dissipative channel if the single dissipative channel condition can be chosen,which helps reduce the entropic uncertainty of the system.For the homodyne feedback control F=λσx(or F=λσy),due to different roles of the entangled qubits A and B,when they are subject to feedback control with different feedback coefficientsλ,the exchange of feedback coefficients will cause variations of the entropic uncertainty.When the feedback coefficient corresponding to the memory qubit B is larger(λB>λA),the steady value of the entropic uncertainty will be small,which is conducive to enhancing the robustness of the system.However,for the feedback control F=λσz,the difference between the feedback coefficients has no effect on the steady values of the entropic uncertainty.
文摘The present work primarily aims to explore the neuronal calcium(Ca^(2+)),IP_(3),and dopamine(DA)signaling systems through a feedback loop model.To date,there has been no exploration of this feedback model in fractional-order dynamical systems.This feedback loop model incorporates several crucial mechanisms like the buffering process,IP_(3)-receptor,ryanodine receptor,plasma membrane Ca^(2+)ATPase and sarcoplasmic/endoplasmic reticulum calcium ATPase(SERCA)pump,leak,sodium-calcium exchanger,voltage-gated Ca^(2+)channel,Orai channels,DA-dependent IP_(3)synthesis,and others.By incorporating these mechanisms,the model aims to provide a more comprehensive and realistic understanding of the system under investigation.The present model incorporates fractional-order dynamics along both spatial and temporal dimensions to examine the impacts of superdiffusion and memory showing Brownian motion of Ca^(2+),IP_(3),and DA signaling molecules.The bidirectional feedback between calcium and IP_(3)signaling systems,unidirectional feedback between calcium and dopamine signaling systems,and unidirectional feedback between IP_(3)and dopamine signaling systems have been incorporated into the present model.These feedback loops establish interactions among calcium,IP_(3),and dopamine signaling systems within neuronal cells.The numerical findings were obtained by using the Crank-Nicholson method with the Grunwald technique for fractional space derivatives and the L1method for fractional time derivatives in conjunction with the Gauss-Seidel Iterations.This research specifically investigates the implications of cell memory as well as superdiffusion on Ca^(2+),IP_(3),and DA dynamics in neuronal cells,which are interactive nonlinear systems.The superdiffusion process results in a reduction in Ca^(2+),IP_(3),and DA concentrations,while cellular memory leads to an increase in ion and molecule concentrations in neuronal cells during the initial time.The disruption of any given process can lead to imbalances in calcium,IP_(3),and DA systems,hence contributing to neurotoxicity and cellular demise.
