Understanding the mechanisms of parent-daughter isotopic mobility at the nanoscale is key to rigorous interpretation of Ue The Pb data and associated dating. Until now, all nanoscale geochronological studies on geolog...Understanding the mechanisms of parent-daughter isotopic mobility at the nanoscale is key to rigorous interpretation of Ue The Pb data and associated dating. Until now, all nanoscale geochronological studies on geological samples have relied on either Transmission Electron Microscope(TEM) or Atom Probe Microscopy(APM) characterizations alone, thus suffering from the respective weaknesses of each technique. Here we focus on monazite crystals from a ~1 Ga, ultrahigh temperature granulite from Rogaland(Norway). This sample has recorded concordant UeP b dates(measured by LA-ICP-MS) that range over 100 My, with the three domains yielding distinct isotopic Ue Pb ages of 1034 ± 6 Ma(D1; Srich core), 1005 ± 7 Ma(D2), and 935 ± 7 Ma(D3), respectively. Combined APM and TEM characterization of these monazite crystals reveal phase separation that led to the isolation of two different radiogenic Pb(Pb*) reservoirs at the nanoscale. The S-rich core of these monazite crystals contains Cae Srich clusters, 5 -10 nm in size, homogenously distributed within the monazite matrix with a mean interparticle distance of 40 -60 nm. The clusters acted as a sink for radiogenic Pb(Pb*) produced in the monazite matrix, which was reset at the nanoscale via Pb diffusion while the grain remained closed at the micro-scale. Compared to the concordant ages given by conventional micro-scale dating of the grain,the apparent nano-scale age of the monazite matrix in between clusters is about 100 Myr younger, which compares remarkably well to the duration of the metamorphic event. This study highlights the capabilities of combined APM-TEM nano-structural and nano-isotopic characterizations in dating and timing of geological events, allowing the detection of processes untraceable with conventional dating methods.展开更多
Presently,we develop a simplified corticothalamic(SCT)model and propose a single-pulse alternately resetting stimulation(SARS)with sequentially applying anodic(A,“+”)or cathodic(C,“−”)phase pulses to the thalamic ...Presently,we develop a simplified corticothalamic(SCT)model and propose a single-pulse alternately resetting stimulation(SARS)with sequentially applying anodic(A,“+”)or cathodic(C,“−”)phase pulses to the thalamic reticular(RE)nuclei,thalamus-cortex(TC)relay nuclei,and cortical excitatory(EX)neurons,respectively.Abatement effects of ACC-SARS of RE,TC,and EX for the 2 Hz-4 Hz spike and wave discharges(SWD)of absence seizures are then concerned.The m∶n on-off ACC-SARS protocol is shown to effectively reduce the SWD with the least current consumption.In particular,when its frequency is out of the 2 Hz-4 Hz SWD dominant rhythm,the desired seizure abatements can be obtained,which can be further improved by our proposed directional steering(DS)stimulation.The dynamical explanations for the SARS induced seizure abatements are lastly given by calculating the averaged mean firing rate(AMFR)of neurons and triggering averaged mean firing rates(TAMFRs)of 2 Hz-4 Hz SWD.展开更多
Feldspar Pb isotopes have been widely used to trace magmatic formation and evolution processes.However,it remains unclear whether post-magmatic thermal events can affect feldspar Pb isotopic ratios.Here,the in situ Pb...Feldspar Pb isotopes have been widely used to trace magmatic formation and evolution processes.However,it remains unclear whether post-magmatic thermal events can affect feldspar Pb isotopic ratios.Here,the in situ Pb isotopic composition of feldspar hosted in granitic rocks(thirteen Archean and one Paleoproterozoic)from the northern Kongling terrane,Yangtze Craton,South China,is analyzed.The samples reveal a substantial variation in their Pb isotopic composition,spanning the gap between the 1.9 Ga and present-day geochrons,which indicates extensive resetting by later tectonothermal events.This resetting was interpreted to have likely resulted from Paleoproterozoic and Neoproterozoic tectonothermal events related to the assembly and breakup of the Columbia and Rodinia supercontinents.These results suggest that Pb isotopes should be used cautiously when tracing magma sources and petrogenesis in magmatic rocks that have experienced post-magmatic reworking.However,the in situ Pb isotopic composition of feldspar in ancient granitoids may also potentially be used to reveal later tectonothermal events.The extensive resetting of the Pb isotopic composition in feldspar by regional thermal events may also provide new insights into our understanding of the Pb isotope paradox.展开更多
Time delays exist widely in real systems, and time-delayed interactions can result in abundant dynamic behaviors and functions in dynamic networks. Inferring the time delays and interactions is challenging due to syst...Time delays exist widely in real systems, and time-delayed interactions can result in abundant dynamic behaviors and functions in dynamic networks. Inferring the time delays and interactions is challenging due to systematic nonlinearity,noises, a lack of information, and so on. Recently, Shi et al. proposed a random state variable resetting method to detect the interactions in a continuous-time dynamic network. By arbitrarily resetting the state variable of a driving node, the equivalent coupling functions of the driving node to any response node in the network can be reconstructed. In this paper,we introduce this method in time-delayed dynamic networks. To infer actual time delays, the nearest neighbor correlation(NNC) function for a given time delay is defined. The significant increments of NNC originate from the delayed effect.Based on the increments, the time delays can be reconstructed and the reconstruction errors depend on the sampling time interval. After time delays are accurately identified, the equivalent coupling functions can also be reconstructed. The numerical results have fully verified the validity of the theoretical analysis.展开更多
Winter plants rely on vernalization,a crucial process for adapting to cold conditions and ensuring successful reproduction.However,understanding the role of histone modifications in guiding the vernalization process i...Winter plants rely on vernalization,a crucial process for adapting to cold conditions and ensuring successful reproduction.However,understanding the role of histone modifications in guiding the vernalization process in winter wheat remains limited.In this study,we investigated the transcriptome and chromatin dynamics in the shoot apex throughout the life cycle of winter wheat in the field.Two core histone modifications,H3K27me3 and H3K36me3,exhibited opposite patterns on the key vernalization gene VERNALIZATION1(VRN1),correlating with its induction during cold exposure.Moreover,the H3K36me3 level remained high at VRN1 after cold exposure,which may maintain its active state.Mutations in FERTILIZATION-INDEPENDENT ENDOSPERM(TaFIE)and SET DOMAIN GROUP 8/EARLY FLOWERING IN SHORT DAYS(TaSDG8/TaEFS),components of the writer complex for H3K27me3 and H3K36me3,respectively,affected flowering time.Intriguingly,VRN1 lost its high expression after the cold exposure memory in the absence of H3K36me3.During embryo development,VRN1 was silenced with the removal of active histone modifications in both winter and spring wheat,with selective restoration of H3K27me3 in winter wheat.The mutant of Tafie-cr-87,a component of H3K27me3“writer”complex,did not influence the silence of VRN1during embryo development,but rather attenuated the cold exposure requirement of winter wheat.Integrating gene expression with H3K27me3 and H3K36me3 patterns identified potential regulators of flowering.This study unveils distinct roles of H3K27me3 and H3K36me3 in controlling vernalization response,maintenance,and resetting in winter wheat.展开更多
The original rock formation age and metamorphic history of Chencai Group are one of the keys to understanding tectonics and early crustal evolution of Zhejiang and Fujian provinces. For the purpose of obtaining the or...The original rock formation age and metamorphic history of Chencai Group are one of the keys to understanding tectonics and early crustal evolution of Zhejiang and Fujian provinces. For the purpose of obtaining the original rock formation age and metamorphic age, Sm-Nd and Rb-Sr isotopic compositions of metamorphic rocks and minerals were determined. Although only the metamorphic age was obtained, Sm-Nd isotopic system resetting among minerals under amphibolite facies metamorphism was discovered, which is of significance for Sm-Nd chronology of metamorphic rocks.展开更多
In this article,the fractional diffusion-advection equation with resetting is introduced to promote the theory of anomalous transport.The fractional equation describes a particle’s non-diffusive motion performing a r...In this article,the fractional diffusion-advection equation with resetting is introduced to promote the theory of anomalous transport.The fractional equation describes a particle’s non-diffusive motion performing a random walk and is reset to its initial position.An analytical method is proposed to obtain the solution of the fractional equation with resetting via Fourier and Laplace transformations.We study the influence of the fractional-order and resetting rate on the probability distributions,and the mean square displacements are analyzed for different cases of anomalous regimes.展开更多
目的探讨逆向半回收技术(RESET)治疗颅内急性大血管闭塞患者的短期疗效。方法回顾性分析2017年11月—2019年3月前瞻性收集的天津市环湖医院使用RESET行机械取栓的286例颅内急性大血管闭塞患者的临床资料。其中男性188例,女性98例,年龄18...目的探讨逆向半回收技术(RESET)治疗颅内急性大血管闭塞患者的短期疗效。方法回顾性分析2017年11月—2019年3月前瞻性收集的天津市环湖医院使用RESET行机械取栓的286例颅内急性大血管闭塞患者的临床资料。其中男性188例,女性98例,年龄18~84岁。根据是否存在颅内动脉粥样硬化性狭窄(ICAS)将患者分为ICAS组186例(65%)、非ICAS组100例(35%)。观察并比较两组患者分别接受RESET取栓后的术后即刻改良脑梗死溶栓(mTICI)分级、穿刺-再通时间、取栓次数、并发症及术后90 d改良Rankin量表(mRS)评分等,以评价短期疗效。结果两组患者的年龄、性别、既往史、入院美国国立卫生研究院中风量表(NIHSS)评分、Alberta卒中项目早期CT(ASPECT)评分等基线资料比较差异均无统计学意义(P>0.05)。286例患者中272例(95.1%)患者实现血管再通成功(95.1%),其中1次取栓实现完全再通209例(73.1%),33例(11.5%)患者取栓后实施了补救性治疗。ICAS组因术后症状性颅内出血死亡2例,非ICAS组因术后多脏器功能衰竭死亡1例。两组患者比较,ICAS组穿刺-再通时间长于非ICAS组[141.36(124.11,156.53)min vs.65.17(53.92,83.25)min,P<0.001],取栓次数低于非ICAS组[1.00(1.00,1.00)vs.1.00(1.00,2.00),P=0.002],差异均有统计学意义(P<0.05)。两组患者最终再通率、1次取栓后完全再通率、远端栓塞或新发部位栓塞及症状性颅内出血、围术期死亡、术后90 d mRS评分等差异均无统计学意义(P>0.05)。结论RESET治疗颅内急性大血管闭塞的短期疗效满意,ICAS组患者再通需要的取栓次数明显低于非ICAS组,该方法尤其适用于合并ICAS的患者。展开更多
Mason Reset(MR),a groundbreaking invention by Clesson E.Mason in 1930 that later became a part of“the universal approach to process control instrumentation”,is revisited in this paper and is shown to consists of thr...Mason Reset(MR),a groundbreaking invention by Clesson E.Mason in 1930 that later became a part of“the universal approach to process control instrumentation”,is revisited in this paper and is shown to consists of three actions:fast(errorcorrection),medium(negative feedback for expanded proportional band)and slow(reset for zero steady-state error).The focus of the paper is on the reset action,generated from a positive feedback loop,and its underlying principles with profound implications to our understanding and practice of automatic control,both basic and advanced.For example,we note that reset control and integral control,contrary to common belief,differ fundamentally in design principle and in practicality.Such difference comes to a head in the event of integrator windup:while reset windup is a problem of actuator saturation,the integrator windup is a runaway situation due to controller instability.In fact,there is no advantage gained in replacing MR with an integrator.In other words,one should not integrate the error directly as in standard PID,since doing so makes the closed-loop system internally unstable.With MR-based control formulated in this paper,there is no such threat of instability and,therefore,no need for any anti-windup mechanisms.Furthermore,the integral control is made scalable in this framework as a tradeoff between the steady-state accuracy and the controller stability.This leads to a novel MR-based control design,scalable in gain and in time to accommodate various process characteristics and design specifications.Simple in construction and transparent in principle,this MR-based control,as a basic framework of design,is readily deployable in scale.展开更多
Domain randomization is a widely adopted technique in deep reinforcement learning(DRL)to improve agent generalization by exposing policies to diverse environmental conditions.This paper investigates the impact of diff...Domain randomization is a widely adopted technique in deep reinforcement learning(DRL)to improve agent generalization by exposing policies to diverse environmental conditions.This paper investigates the impact of different reset strategies,normal,non-randomized,and randomized,on agent performance using the Deep Deterministic Policy Gradient(DDPG)and Twin Delayed DDPG(TD3)algorithms within the CarRacing-v2 environment.Two experimental setups were conducted:an extended training regime with DDPG for 1000 steps per episode across 1000 episodes,and a fast execution setup comparing DDPG and TD3 for 30 episodes with 50 steps per episode under constrained computational resources.A step-based reward scaling mechanism was applied under the randomized reset condition to promote broader state exploration.Experimental results showthat randomized resets significantly enhance learning efficiency and generalization,with DDPG demonstrating superior performance across all reset strategies.In particular,DDPG combined with randomized resets achieves the highest smoothed rewards(reaching approximately 15),best stability,and fastest convergence.These differences are statistically significant,as confirmed by t-tests:DDPG outperforms TD3 under randomized(t=−101.91,p<0.0001),normal(t=−21.59,p<0.0001),and non-randomized(t=−62.46,p<0.0001)reset conditions.The findings underscore the critical role of reset strategy and reward shaping in enhancing the robustness and adaptability of DRL agents in continuous control tasks,particularly in environments where computational efficiency and training stability are crucial.展开更多
To identify systems with non-uniformly sampled input data, a recursive Bayesian identification algorithm with covariance resetting is proposed. Using estimated noise transfer function as a dynamic filter, the system w...To identify systems with non-uniformly sampled input data, a recursive Bayesian identification algorithm with covariance resetting is proposed. Using estimated noise transfer function as a dynamic filter, the system with colored noise is transformed into the system with white noise. In order to improve estimates, the estimated noise variance is employed as a weighting factor in the algorithm. Meanwhile, a modified covariance resetting method is also integrated in the proposed algorithm to increase the convergence rate. A numerical example and an industrial example validate the proposed algorithm.展开更多
基金Both UJM and CNRS (INSU TelluS-SYSTER) are thanked for financial support for AMSG and ATL. The Australian Resource Characterisation Facility (ARCF), under the auspices of the National Resource Sciences Precinct (NRSP) - a collaboration between CSIRO, Curtin University and The University of Western Australia e is supported by the Science and Industry Endowment Fund (SIEF RI13-01)
文摘Understanding the mechanisms of parent-daughter isotopic mobility at the nanoscale is key to rigorous interpretation of Ue The Pb data and associated dating. Until now, all nanoscale geochronological studies on geological samples have relied on either Transmission Electron Microscope(TEM) or Atom Probe Microscopy(APM) characterizations alone, thus suffering from the respective weaknesses of each technique. Here we focus on monazite crystals from a ~1 Ga, ultrahigh temperature granulite from Rogaland(Norway). This sample has recorded concordant UeP b dates(measured by LA-ICP-MS) that range over 100 My, with the three domains yielding distinct isotopic Ue Pb ages of 1034 ± 6 Ma(D1; Srich core), 1005 ± 7 Ma(D2), and 935 ± 7 Ma(D3), respectively. Combined APM and TEM characterization of these monazite crystals reveal phase separation that led to the isolation of two different radiogenic Pb(Pb*) reservoirs at the nanoscale. The S-rich core of these monazite crystals contains Cae Srich clusters, 5 -10 nm in size, homogenously distributed within the monazite matrix with a mean interparticle distance of 40 -60 nm. The clusters acted as a sink for radiogenic Pb(Pb*) produced in the monazite matrix, which was reset at the nanoscale via Pb diffusion while the grain remained closed at the micro-scale. Compared to the concordant ages given by conventional micro-scale dating of the grain,the apparent nano-scale age of the monazite matrix in between clusters is about 100 Myr younger, which compares remarkably well to the duration of the metamorphic event. This study highlights the capabilities of combined APM-TEM nano-structural and nano-isotopic characterizations in dating and timing of geological events, allowing the detection of processes untraceable with conventional dating methods.
基金Project supported by the National Natural Science Foundation of China(Nos.11702018,11932003,and 11672074)。
文摘Presently,we develop a simplified corticothalamic(SCT)model and propose a single-pulse alternately resetting stimulation(SARS)with sequentially applying anodic(A,“+”)or cathodic(C,“−”)phase pulses to the thalamic reticular(RE)nuclei,thalamus-cortex(TC)relay nuclei,and cortical excitatory(EX)neurons,respectively.Abatement effects of ACC-SARS of RE,TC,and EX for the 2 Hz-4 Hz spike and wave discharges(SWD)of absence seizures are then concerned.The m∶n on-off ACC-SARS protocol is shown to effectively reduce the SWD with the least current consumption.In particular,when its frequency is out of the 2 Hz-4 Hz SWD dominant rhythm,the desired seizure abatements can be obtained,which can be further improved by our proposed directional steering(DS)stimulation.The dynamical explanations for the SARS induced seizure abatements are lastly given by calculating the averaged mean firing rate(AMFR)of neurons and triggering averaged mean firing rates(TAMFRs)of 2 Hz-4 Hz SWD.
基金supported by the Key Laboratory of Gold Mineralization Processes and Resource Utilization,MNRShandong Provincial Key Laboratory of Metallogenic Geological Process and Resource Utilization(Grant No.KFKT202103)National Natural Science Foundation of China(Grant No.41876037)。
文摘Feldspar Pb isotopes have been widely used to trace magmatic formation and evolution processes.However,it remains unclear whether post-magmatic thermal events can affect feldspar Pb isotopic ratios.Here,the in situ Pb isotopic composition of feldspar hosted in granitic rocks(thirteen Archean and one Paleoproterozoic)from the northern Kongling terrane,Yangtze Craton,South China,is analyzed.The samples reveal a substantial variation in their Pb isotopic composition,spanning the gap between the 1.9 Ga and present-day geochrons,which indicates extensive resetting by later tectonothermal events.This resetting was interpreted to have likely resulted from Paleoproterozoic and Neoproterozoic tectonothermal events related to the assembly and breakup of the Columbia and Rodinia supercontinents.These results suggest that Pb isotopes should be used cautiously when tracing magma sources and petrogenesis in magmatic rocks that have experienced post-magmatic reworking.However,the in situ Pb isotopic composition of feldspar in ancient granitoids may also potentially be used to reveal later tectonothermal events.The extensive resetting of the Pb isotopic composition in feldspar by regional thermal events may also provide new insights into our understanding of the Pb isotope paradox.
文摘Time delays exist widely in real systems, and time-delayed interactions can result in abundant dynamic behaviors and functions in dynamic networks. Inferring the time delays and interactions is challenging due to systematic nonlinearity,noises, a lack of information, and so on. Recently, Shi et al. proposed a random state variable resetting method to detect the interactions in a continuous-time dynamic network. By arbitrarily resetting the state variable of a driving node, the equivalent coupling functions of the driving node to any response node in the network can be reconstructed. In this paper,we introduce this method in time-delayed dynamic networks. To infer actual time delays, the nearest neighbor correlation(NNC) function for a given time delay is defined. The significant increments of NNC originate from the delayed effect.Based on the increments, the time delays can be reconstructed and the reconstruction errors depend on the sampling time interval. After time delays are accurately identified, the equivalent coupling functions can also be reconstructed. The numerical results have fully verified the validity of the theoretical analysis.
基金supported by National Natural Science Foundation(31970529)Beijing Natural Science Foundation Outstanding Youth Project(JQ23026)+1 种基金National Key Research and Development Program of China(2021YFD1201500)the Major Basic Research Program of Shandong Natural Science Foundation(ZR2019ZD15)。
文摘Winter plants rely on vernalization,a crucial process for adapting to cold conditions and ensuring successful reproduction.However,understanding the role of histone modifications in guiding the vernalization process in winter wheat remains limited.In this study,we investigated the transcriptome and chromatin dynamics in the shoot apex throughout the life cycle of winter wheat in the field.Two core histone modifications,H3K27me3 and H3K36me3,exhibited opposite patterns on the key vernalization gene VERNALIZATION1(VRN1),correlating with its induction during cold exposure.Moreover,the H3K36me3 level remained high at VRN1 after cold exposure,which may maintain its active state.Mutations in FERTILIZATION-INDEPENDENT ENDOSPERM(TaFIE)and SET DOMAIN GROUP 8/EARLY FLOWERING IN SHORT DAYS(TaSDG8/TaEFS),components of the writer complex for H3K27me3 and H3K36me3,respectively,affected flowering time.Intriguingly,VRN1 lost its high expression after the cold exposure memory in the absence of H3K36me3.During embryo development,VRN1 was silenced with the removal of active histone modifications in both winter and spring wheat,with selective restoration of H3K27me3 in winter wheat.The mutant of Tafie-cr-87,a component of H3K27me3“writer”complex,did not influence the silence of VRN1during embryo development,but rather attenuated the cold exposure requirement of winter wheat.Integrating gene expression with H3K27me3 and H3K36me3 patterns identified potential regulators of flowering.This study unveils distinct roles of H3K27me3 and H3K36me3 in controlling vernalization response,maintenance,and resetting in winter wheat.
基金Project supported by the National Natural Science Foundation of China.
文摘The original rock formation age and metamorphic history of Chencai Group are one of the keys to understanding tectonics and early crustal evolution of Zhejiang and Fujian provinces. For the purpose of obtaining the original rock formation age and metamorphic age, Sm-Nd and Rb-Sr isotopic compositions of metamorphic rocks and minerals were determined. Although only the metamorphic age was obtained, Sm-Nd isotopic system resetting among minerals under amphibolite facies metamorphism was discovered, which is of significance for Sm-Nd chronology of metamorphic rocks.
文摘In this article,the fractional diffusion-advection equation with resetting is introduced to promote the theory of anomalous transport.The fractional equation describes a particle’s non-diffusive motion performing a random walk and is reset to its initial position.An analytical method is proposed to obtain the solution of the fractional equation with resetting via Fourier and Laplace transformations.We study the influence of the fractional-order and resetting rate on the probability distributions,and the mean square displacements are analyzed for different cases of anomalous regimes.
文摘目的探讨逆向半回收技术(RESET)治疗颅内急性大血管闭塞患者的短期疗效。方法回顾性分析2017年11月—2019年3月前瞻性收集的天津市环湖医院使用RESET行机械取栓的286例颅内急性大血管闭塞患者的临床资料。其中男性188例,女性98例,年龄18~84岁。根据是否存在颅内动脉粥样硬化性狭窄(ICAS)将患者分为ICAS组186例(65%)、非ICAS组100例(35%)。观察并比较两组患者分别接受RESET取栓后的术后即刻改良脑梗死溶栓(mTICI)分级、穿刺-再通时间、取栓次数、并发症及术后90 d改良Rankin量表(mRS)评分等,以评价短期疗效。结果两组患者的年龄、性别、既往史、入院美国国立卫生研究院中风量表(NIHSS)评分、Alberta卒中项目早期CT(ASPECT)评分等基线资料比较差异均无统计学意义(P>0.05)。286例患者中272例(95.1%)患者实现血管再通成功(95.1%),其中1次取栓实现完全再通209例(73.1%),33例(11.5%)患者取栓后实施了补救性治疗。ICAS组因术后症状性颅内出血死亡2例,非ICAS组因术后多脏器功能衰竭死亡1例。两组患者比较,ICAS组穿刺-再通时间长于非ICAS组[141.36(124.11,156.53)min vs.65.17(53.92,83.25)min,P<0.001],取栓次数低于非ICAS组[1.00(1.00,1.00)vs.1.00(1.00,2.00),P=0.002],差异均有统计学意义(P<0.05)。两组患者最终再通率、1次取栓后完全再通率、远端栓塞或新发部位栓塞及症状性颅内出血、围术期死亡、术后90 d mRS评分等差异均无统计学意义(P>0.05)。结论RESET治疗颅内急性大血管闭塞的短期疗效满意,ICAS组患者再通需要的取栓次数明显低于非ICAS组,该方法尤其适用于合并ICAS的患者。
文摘Mason Reset(MR),a groundbreaking invention by Clesson E.Mason in 1930 that later became a part of“the universal approach to process control instrumentation”,is revisited in this paper and is shown to consists of three actions:fast(errorcorrection),medium(negative feedback for expanded proportional band)and slow(reset for zero steady-state error).The focus of the paper is on the reset action,generated from a positive feedback loop,and its underlying principles with profound implications to our understanding and practice of automatic control,both basic and advanced.For example,we note that reset control and integral control,contrary to common belief,differ fundamentally in design principle and in practicality.Such difference comes to a head in the event of integrator windup:while reset windup is a problem of actuator saturation,the integrator windup is a runaway situation due to controller instability.In fact,there is no advantage gained in replacing MR with an integrator.In other words,one should not integrate the error directly as in standard PID,since doing so makes the closed-loop system internally unstable.With MR-based control formulated in this paper,there is no such threat of instability and,therefore,no need for any anti-windup mechanisms.Furthermore,the integral control is made scalable in this framework as a tradeoff between the steady-state accuracy and the controller stability.This leads to a novel MR-based control design,scalable in gain and in time to accommodate various process characteristics and design specifications.Simple in construction and transparent in principle,this MR-based control,as a basic framework of design,is readily deployable in scale.
基金supported by the Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia(Project No.MoE-IF-UJ-R2-22-04220773-1).
文摘Domain randomization is a widely adopted technique in deep reinforcement learning(DRL)to improve agent generalization by exposing policies to diverse environmental conditions.This paper investigates the impact of different reset strategies,normal,non-randomized,and randomized,on agent performance using the Deep Deterministic Policy Gradient(DDPG)and Twin Delayed DDPG(TD3)algorithms within the CarRacing-v2 environment.Two experimental setups were conducted:an extended training regime with DDPG for 1000 steps per episode across 1000 episodes,and a fast execution setup comparing DDPG and TD3 for 30 episodes with 50 steps per episode under constrained computational resources.A step-based reward scaling mechanism was applied under the randomized reset condition to promote broader state exploration.Experimental results showthat randomized resets significantly enhance learning efficiency and generalization,with DDPG demonstrating superior performance across all reset strategies.In particular,DDPG combined with randomized resets achieves the highest smoothed rewards(reaching approximately 15),best stability,and fastest convergence.These differences are statistically significant,as confirmed by t-tests:DDPG outperforms TD3 under randomized(t=−101.91,p<0.0001),normal(t=−21.59,p<0.0001),and non-randomized(t=−62.46,p<0.0001)reset conditions.The findings underscore the critical role of reset strategy and reward shaping in enhancing the robustness and adaptability of DRL agents in continuous control tasks,particularly in environments where computational efficiency and training stability are crucial.
基金supported by National Natural Science Foundation of China(Nos.61273142 and 51477070)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Foundation for Six Talents by Jiangsu Province and Graduate Scientific Innovation Projects of Jiangsu University(No.KYXX_0003)
文摘To identify systems with non-uniformly sampled input data, a recursive Bayesian identification algorithm with covariance resetting is proposed. Using estimated noise transfer function as a dynamic filter, the system with colored noise is transformed into the system with white noise. In order to improve estimates, the estimated noise variance is employed as a weighting factor in the algorithm. Meanwhile, a modified covariance resetting method is also integrated in the proposed algorithm to increase the convergence rate. A numerical example and an industrial example validate the proposed algorithm.
