We aim to further study the global stability of Boolean control networks(BCNs)under aperiodic sampleddata control(ASDC).According to our previous work,it is known that a BCN under ASDC can be transformed into a switch...We aim to further study the global stability of Boolean control networks(BCNs)under aperiodic sampleddata control(ASDC).According to our previous work,it is known that a BCN under ASDC can be transformed into a switched Boolean network(SBN),and further global stability of the BCN under ASDC can be obtained by studying the global stability of the transformed SBN.Unfortunately,since the major idea of our previous work is to use stable subsystems to offset the state divergence caused by unstable subsystems,the SBN considered has at least one stable subsystem.The central thought in this paper is that switching behavior also has good stabilization;i.e.,the SBN can also be stable with appropriate switching laws designed,even if all subsystems are unstable.This is completely different from that in our previous work.Specifically,for this case,the dwell time(DT)should be limited within a pair of upper and lower bounds.By means of the discretized Lyapunov function and DT,a sufficient condition for global stability is obtained.Finally,the above results are demonstrated by a biological example.展开更多
In order to reduce or eliminate the multiple access interference in code division multiple access (CDMA) systems, we need to design a set of spreading sequences with good autocorrelation functions (ACF) and crosscorre...In order to reduce or eliminate the multiple access interference in code division multiple access (CDMA) systems, we need to design a set of spreading sequences with good autocorrelation functions (ACF) and crosscorrelation functions (CCF). The importance of the spreading codes to CDMA systems cannot be overemphasized, for the type of the code used, its length, and its chip rate set bounds on the capability of the system that can be changed only by changing the code. Several new lower bounds which are stronger than the well-known Sarwate bounds, Welch bounds and Levenshtein bounds for binary sequence set with respect to the spreading sequence length, family size, maximum aperiodic autocorrelation sidelobe and maximum aperiodic crosscorrelation value are established.展开更多
Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Cu...Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.展开更多
An increasing number of DRTS （Distributed model. The key challenges of such DRTS are guaranteeing Real-Time Systems） are employing an end-to-end aperiodic task utilization on multiple processors to achieve overload ...An increasing number of DRTS （Distributed model. The key challenges of such DRTS are guaranteeing Real-Time Systems） are employing an end-to-end aperiodic task utilization on multiple processors to achieve overload protection, and meeting the end-to-end deadlines of aperiodic tasks. This paper proposes an end-to-end utilization control architecture and an IC-EAT （Integration Control for End-to-End Aperiodic Tasks） algorithm, which features a distributed feedback loop that dynamically enforces the desired utilization bound on multiple processors. IC-EAT integrates admission control with feedback control, which is able to dynamically determine the QoS （Quality of Service） of incoming tasks and guarantee the end-to-end deadlines of admitted tasks. Then an LQOCM （Linear Quadratic Optimal Control Model） is presented. Finally, experiments demonstrate that, for the end-to-end DRTS whose control matrix G falls into the stable region, the IC-EAT is convergent and stable. Moreover,it is capable of providing better QoS guarantees for end-to-end aperiodic tasks and improving the system throughput.展开更多
Herein, the dynamics and flow fields of an inverted flag are studied using hydrogen bubble flow visualization and particle image velocimetry technologies at different height-to-length ratios and flow velocities in a w...Herein, the dynamics and flow fields of an inverted flag are studied using hydrogen bubble flow visualization and particle image velocimetry technologies at different height-to-length ratios and flow velocities in a water tunnel. Results show that the heightto-length ratio of the inverted flag at which the critical flow velocity remains nearly constant is approximately 1.4. Moreover, a nonperiodic flapping phenomenon is observed under various height-to-length ratios. This phenomenon may be attributed to the existence of multiple equilibrium solutions to the self-excited vibration system, thus engendering chaos in the system comprising an inverted flag and surrounding fluid. Other indications that the system has entered chaos include multiple frequencies, nonoverlapping phase diagram, and positive Lyapunov exponent. Further discussion of the flow fields around the inverted flag reveals that the large-amplitude oscillation is due to the flow separation, while the flapping instability is a static divergence instability. In the large flapping mode, the starting leading-edge vortex(LEV) is wrapped by Kelvin-Helmholtz instabilities,which are arranged at almost uniform spacing along a circular path. In addition, the variation in position, circulation, and radius of the starting LEV are discussed in detail.展开更多
The band gap of a photonic crystal (PhC) cavity intrinsically avoids HOM problems. In this paper, we present a new PBG structure based on the possible advantage of using hybrid structures and aperiodic lattices. This ...The band gap of a photonic crystal (PhC) cavity intrinsically avoids HOM problems. In this paper, we present a new PBG structure based on the possible advantage of using hybrid structures and aperiodic lattices. This novel hybrid and aperiodically ordered cavity was designed for apparently higher Q-factor (more than 10300) and achieving large accelerating field gradient. The HOMs in the cavity are able to be absorbed efficiently.展开更多
Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems,which probe electron temperature and density during inertial confinement fusion processes.In this study,aperiodic Mo/B_(4)C multi...Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems,which probe electron temperature and density during inertial confinement fusion processes.In this study,aperiodic Mo/B_(4)C multilayer mirrors of varied thick-nesses were investigated for X-ray plasma diagnostics at the 9.67-keV W-Lβline.The thickness distribution of the aperiodic multilayers was designed using the first Bragg diffraction condition and then optimized through a simplex algorithm to realize a narrow bandwidth and consistent spectral response.To enhance spectral accuracy,further refinements were undertaken by matching the grazing incidence X-ray reflectivity data with actual structural parameters.X-ray reflectivity measurements from the SSRF synchrotron radiation facility on the optimized sample showed a reflectivity of 29.7±2.6%,flat-band range of 1.3 keV,and bandwidth of 1.7 keV,making it suitable for high-temperature plasma diagnostics.The study explored the potential of predicting the 9.67 keV reflectivity spectrum using the fitting data from the grazing incidence X-ray reflectivity curves at 8.05 keV.Additionally,the short-term thermal stability of an aperiodic multilayer was assessed using temperature-dependent in situ X-ray measurements.Shifts in the reflectivity spectrum during annealing were attributed to interdiffusion and interfacial relaxation.The research team recommends the aperiodic Mo/B_(4)C multilayer mirror for operations below 300℃.展开更多
The popularly used circulant matrix model of deconvolution is mostly heavily ill-posed or singular and it is not suitable to many blind deconvolution problems. The aperiodic matrix model can improve the condition numb...The popularly used circulant matrix model of deconvolution is mostly heavily ill-posed or singular and it is not suitable to many blind deconvolution problems. The aperiodic matrix model can improve the condition number of deconvolution problems and its accommodation is much wider than the circulant one's. This paper discusses a comparison of the two models including their ill-posedness, the rationality of the approximation by the models, and their computational efficiency. The comparison shows that the aperiodic model is promising in the development of new restoration algorithms.展开更多
Stochastic resonance （SR） is based on the cooperative effect between the stochastic dynamical system and the external forcing. As is well known, the cooperative effect is produced by adding noises. In this paper, we...Stochastic resonance （SR） is based on the cooperative effect between the stochastic dynamical system and the external forcing. As is well known, the cooperative effect is produced by adding noises. In this paper, we show the evidence that by changing the system parameters and the signal intensity, a nonlinear system in the presence of an input aperiodic signal can yield the cooperative effect, with the noise fixed. To quantify the nonlinear system output, we determine the theoretical bit error rate （BER）. By numerical simulation, the validity of the theoretical derivation is checked. Besides, we show that parameter-induced SR is more realizable than SR via adding noises, especially when the noise intensity exceeds the resonance level, or when the characteristic of the noise is not known.展开更多
Because of descriptive nonlinearity and computational inefficiency,topology optimization with fatigue life under aperiodic loads has developed slowly.A fatigue constraint topology optimization method based on bidirect...Because of descriptive nonlinearity and computational inefficiency,topology optimization with fatigue life under aperiodic loads has developed slowly.A fatigue constraint topology optimization method based on bidirectional evolutionary structural optimization(BESO)under an aperiodic load is proposed in this paper.In viewof the severe nonlinearity of fatigue damagewith respect to design variables,effective stress cycles are extracted through transient dynamic analysis.Based on the Miner cumulative damage theory and life requirements,a fatigue constraint is first quantified and then transformed into a stress problem.Then,a normalized termination criterion is proposed by approximatemaximum stress measured by global stress using a P-normaggregation function.Finally,optimization examples show that the proposed algorithm can not only meet the requirements of fatigue life but also obtain a reasonable configuration.展开更多
基金Project supported by the Natural Science Foundation of Jiangsu Province,China(No.BK20170019)the Fundamental Research Funds for the Central Universities+2 种基金the National Natural Science Foundation of China(Nos.61973078,61573102,and 11671158)Hong Kong RGC GRF,China(No.17301519)IMR and RAE Research Fund from Faculty of Science,HKU,China。
文摘We aim to further study the global stability of Boolean control networks(BCNs)under aperiodic sampleddata control(ASDC).According to our previous work,it is known that a BCN under ASDC can be transformed into a switched Boolean network(SBN),and further global stability of the BCN under ASDC can be obtained by studying the global stability of the transformed SBN.Unfortunately,since the major idea of our previous work is to use stable subsystems to offset the state divergence caused by unstable subsystems,the SBN considered has at least one stable subsystem.The central thought in this paper is that switching behavior also has good stabilization;i.e.,the SBN can also be stable with appropriate switching laws designed,even if all subsystems are unstable.This is completely different from that in our previous work.Specifically,for this case,the dwell time(DT)should be limited within a pair of upper and lower bounds.By means of the discretized Lyapunov function and DT,a sufficient condition for global stability is obtained.Finally,the above results are demonstrated by a biological example.
基金supported by the National Natural Science Foundation of China(NSFC)the Research Grants Council of Hong Kong(RGC)joint research scheme(Grant No.60218001)+1 种基金the NSFC project(Grant No.69931050)the National Key Laboratory of Communications(UESTC),and the Royal Society,UK.
文摘In order to reduce or eliminate the multiple access interference in code division multiple access (CDMA) systems, we need to design a set of spreading sequences with good autocorrelation functions (ACF) and crosscorrelation functions (CCF). The importance of the spreading codes to CDMA systems cannot be overemphasized, for the type of the code used, its length, and its chip rate set bounds on the capability of the system that can be changed only by changing the code. Several new lower bounds which are stronger than the well-known Sarwate bounds, Welch bounds and Levenshtein bounds for binary sequence set with respect to the spreading sequence length, family size, maximum aperiodic autocorrelation sidelobe and maximum aperiodic crosscorrelation value are established.
基金supported by the National Natural Science Foundation of China,No.82071254(to WZ).
文摘Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.
文摘An increasing number of DRTS （Distributed model. The key challenges of such DRTS are guaranteeing Real-Time Systems） are employing an end-to-end aperiodic task utilization on multiple processors to achieve overload protection, and meeting the end-to-end deadlines of aperiodic tasks. This paper proposes an end-to-end utilization control architecture and an IC-EAT （Integration Control for End-to-End Aperiodic Tasks） algorithm, which features a distributed feedback loop that dynamically enforces the desired utilization bound on multiple processors. IC-EAT integrates admission control with feedback control, which is able to dynamically determine the QoS （Quality of Service） of incoming tasks and guarantee the end-to-end deadlines of admitted tasks. Then an LQOCM （Linear Quadratic Optimal Control Model） is presented. Finally, experiments demonstrate that, for the end-to-end DRTS whose control matrix G falls into the stable region, the IC-EAT is convergent and stable. Moreover,it is capable of providing better QoS guarantees for end-to-end aperiodic tasks and improving the system throughput.
基金supported by the National Natural Science Foundation of China(Grant Nos.11721202,and 11761131009)
文摘Herein, the dynamics and flow fields of an inverted flag are studied using hydrogen bubble flow visualization and particle image velocimetry technologies at different height-to-length ratios and flow velocities in a water tunnel. Results show that the heightto-length ratio of the inverted flag at which the critical flow velocity remains nearly constant is approximately 1.4. Moreover, a nonperiodic flapping phenomenon is observed under various height-to-length ratios. This phenomenon may be attributed to the existence of multiple equilibrium solutions to the self-excited vibration system, thus engendering chaos in the system comprising an inverted flag and surrounding fluid. Other indications that the system has entered chaos include multiple frequencies, nonoverlapping phase diagram, and positive Lyapunov exponent. Further discussion of the flow fields around the inverted flag reveals that the large-amplitude oscillation is due to the flow separation, while the flapping instability is a static divergence instability. In the large flapping mode, the starting leading-edge vortex(LEV) is wrapped by Kelvin-Helmholtz instabilities,which are arranged at almost uniform spacing along a circular path. In addition, the variation in position, circulation, and radius of the starting LEV are discussed in detail.
基金supported by the National Natural Science Foundation of China (Grant No. 10675116)the Major State Basic Research Development Programme of China (Grant No. 2011CB808301)
文摘The band gap of a photonic crystal (PhC) cavity intrinsically avoids HOM problems. In this paper, we present a new PBG structure based on the possible advantage of using hybrid structures and aperiodic lattices. This novel hybrid and aperiodically ordered cavity was designed for apparently higher Q-factor (more than 10300) and achieving large accelerating field gradient. The HOMs in the cavity are able to be absorbed efficiently.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Nos.11875204 and U1932167)Fundamental Research Funds for the Central Universities(Nos.22120210446 and 22120180070)the Presidential Foundation of China Academy of Engineering Physics(No.YZJJLX2019011).
文摘Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems,which probe electron temperature and density during inertial confinement fusion processes.In this study,aperiodic Mo/B_(4)C multilayer mirrors of varied thick-nesses were investigated for X-ray plasma diagnostics at the 9.67-keV W-Lβline.The thickness distribution of the aperiodic multilayers was designed using the first Bragg diffraction condition and then optimized through a simplex algorithm to realize a narrow bandwidth and consistent spectral response.To enhance spectral accuracy,further refinements were undertaken by matching the grazing incidence X-ray reflectivity data with actual structural parameters.X-ray reflectivity measurements from the SSRF synchrotron radiation facility on the optimized sample showed a reflectivity of 29.7±2.6%,flat-band range of 1.3 keV,and bandwidth of 1.7 keV,making it suitable for high-temperature plasma diagnostics.The study explored the potential of predicting the 9.67 keV reflectivity spectrum using the fitting data from the grazing incidence X-ray reflectivity curves at 8.05 keV.Additionally,the short-term thermal stability of an aperiodic multilayer was assessed using temperature-dependent in situ X-ray measurements.Shifts in the reflectivity spectrum during annealing were attributed to interdiffusion and interfacial relaxation.The research team recommends the aperiodic Mo/B_(4)C multilayer mirror for operations below 300℃.
文摘The popularly used circulant matrix model of deconvolution is mostly heavily ill-posed or singular and it is not suitable to many blind deconvolution problems. The aperiodic matrix model can improve the condition number of deconvolution problems and its accommodation is much wider than the circulant one's. This paper discusses a comparison of the two models including their ill-posedness, the rationality of the approximation by the models, and their computational efficiency. The comparison shows that the aperiodic model is promising in the development of new restoration algorithms.
基金Project supported by the National Natural Science Foundation of China （Grant No 10332030） and the State Key Program for Basic Research of China （Grant No 5132103ZZT21B）.
文摘Stochastic resonance （SR） is based on the cooperative effect between the stochastic dynamical system and the external forcing. As is well known, the cooperative effect is produced by adding noises. In this paper, we show the evidence that by changing the system parameters and the signal intensity, a nonlinear system in the presence of an input aperiodic signal can yield the cooperative effect, with the noise fixed. To quantify the nonlinear system output, we determine the theoretical bit error rate （BER）. By numerical simulation, the validity of the theoretical derivation is checked. Besides, we show that parameter-induced SR is more realizable than SR via adding noises, especially when the noise intensity exceeds the resonance level, or when the characteristic of the noise is not known.
基金Chinese National Natural Science Foundation(No.51890881)Science and Technology Project of Hebei Education Department(Nos.ZD2020156,QN2018228).
文摘Because of descriptive nonlinearity and computational inefficiency,topology optimization with fatigue life under aperiodic loads has developed slowly.A fatigue constraint topology optimization method based on bidirectional evolutionary structural optimization(BESO)under an aperiodic load is proposed in this paper.In viewof the severe nonlinearity of fatigue damagewith respect to design variables,effective stress cycles are extracted through transient dynamic analysis.Based on the Miner cumulative damage theory and life requirements,a fatigue constraint is first quantified and then transformed into a stress problem.Then,a normalized termination criterion is proposed by approximatemaximum stress measured by global stress using a P-normaggregation function.Finally,optimization examples show that the proposed algorithm can not only meet the requirements of fatigue life but also obtain a reasonable configuration.
