BACKGROUND:Hemiplegia,a prevalent stroke-related condition,is often studied for motor dysfunction;however,spasticity remains under-researched.Abnormal muscle tone significantly hinders hemiplegic patients’walking rec...BACKGROUND:Hemiplegia,a prevalent stroke-related condition,is often studied for motor dysfunction;however,spasticity remains under-researched.Abnormal muscle tone significantly hinders hemiplegic patients’walking recovery.OBJECTIVE:To determine whether early suspension-protected training with a personal assistant machine for stroke patients enhances walking ability and prevents muscle spasms.METHODS:Thirty-two early-stage stroke patients from Shenzhen University General Hospital and the China Rehabilitation Research Center were randomly assigned to the experimental group(n=16)and the control group(n=16).Both groups underwent 4 weeks of gait training under the suspension protection system for 30 minutes daily,5 days a week.The experimental group used the personal assistant machine during training.Three-dimensional gait analysis(using the Cortex motion capture system),Brunnstrom staging,Fugl-Meyer Assessment for lower limb motor function,Fugl-Meyer balance function,and the modified Ashworth Scale were evaluated within 1 week before the intervention and after 4 weeks of intervention.RESULTS AND CONCLUSION:After the 4-week intervention,all outcome measures showed significant changes in each group.The experimental group had a small but significant increase in the modified Ashworth Scale score(P<0.05,d=|0.15|),while the control group had a large significant increase(P<0.05,d=|1.48|).The experimental group demonstrated greater improvements in walking speed(16.5 to 38.44 cm/s,P<0.05,d=|4.01|),step frequency(46.44 to 64.94 steps/min,P<0.05,d=|2.32|),stride length(15.50 to 29.81 cm,P<0.05,d=|3.44|),and peak hip and knee flexion(d=|1.82|to|2.17|).After treatment,the experimental group showed significantly greater improvements than the control group in walking speed(38.44 vs.26.63 cm/s,P<0.05,d=|2.75|),stride length,peak hip and knee flexion(d=|1.31|to|1.45|),step frequency(64.94 vs.59.38 steps/min,P<0.05,d=|0.85|),and a reduced support phase(bilateral:24.31%vs.28.38%,P<0.05,d=|0.88|;non-paretic:66.19%vs.70.13%,P<0.05,d=|0.94|).For early hemiplegia,personal assistant machine-assisted gait training under the suspension protection system helps establish a correct gait pattern,prevents muscle spasms,and improves motor function.展开更多
In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are dif...In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].展开更多
The no-cloning theorem has sparked considerable interest in achieving high-fidelity approximate quantum cloning.Most of the previous studies mainly focused on the cloning of single particle states,and cloning schemes ...The no-cloning theorem has sparked considerable interest in achieving high-fidelity approximate quantum cloning.Most of the previous studies mainly focused on the cloning of single particle states,and cloning schemes used there are incapable of cloning quantum entangled states in multipartite systems.Few schemes were proposed for cloning multiparticle states,which consume more entanglement resources with loss of qubits,and the fidelity of the cloned state is relatively low.In this paper,cloning schemes for bipartite and tripartite entangled states based on photonic quantum walk and entanglement swapping are proposed.The results show that according to the proposed schemes,two high-fidelity(up to 0.75)cloned states can be obtained with less quantum resource consumption.Because of the simple cloning steps,few quantum resources and high fidelity,these schemes are both efficient and feasible.Moreover,this cloning machine eliminates the need for tracing out cloning machine,thereby minimizing resource waste.展开更多
Missiles provide long-range precision strike capabilities and have become a cornerstone of modern warfare.The contrail clouds formed by missile during their active flight phase present significant chal-lenges to high-...Missiles provide long-range precision strike capabilities and have become a cornerstone of modern warfare.The contrail clouds formed by missile during their active flight phase present significant chal-lenges to high-altitude environmental observation and target detection and tracking.Existing studies primarily focus on specific airspace regions,leaving critical gaps in understanding the effects of long dispersion times,wide altitude ranges,and variable atmospheric conditions on missile contrail clouds.To address these gaps,this article develops a numerical method based on the Lagrangian random walk model,which incorporates various velocity variation terms,including particle velocity caused by the difference of wind field,by the thermal motion of local gas molecules and by random collisions between contrail cloud particles to capture the influence of environmental wind fields,atmospheric conditions,and particle concentrations on the motion of contrail cloud particles.A general coordinate system aligned with the missile's flight trajectory is employed to represent particle distribution characteristics.The proposed method is in good agreement with the conducted experiments as well as with the available numerical simulations.The results demonstrate that the proposed model effectively simulates the dispersion state of contrail clouds,accurately reflecting the impact of large-scale wind field variations and altitude changes with high computational efficiency.Additionally,simulation results indicate that the increased distance between gas molecules in rarefied environments facilitates enhanced particle dispersion,while larger particles exhibit a faster dispersion rate due to their greater mass.展开更多
[Objectives]To synthesize evidence on HIIT versus moderate-intensity continuous training(MICT)or routine rehabilitation in stroke survivors.[Methods]We systematically searched 8 databases(PubMed,EMBASE,CENTRAL,Web of ...[Objectives]To synthesize evidence on HIIT versus moderate-intensity continuous training(MICT)or routine rehabilitation in stroke survivors.[Methods]We systematically searched 8 databases(PubMed,EMBASE,CENTRAL,Web of Science,SPORTSDiscus,PsycINFO,SCOPUS,CINAHL)up to May 2025.Seventeen randomized controlled trials(RCTs;total n=1142)met inclusion criteria:adults with stroke,device-based HIIT(≥70%HRR/VO 2peak),and outcomes assessing VO_(2)peak,6-min walk distance(6MWD),or Berg Balance Scale(BBS).Methodological quality was evaluated using the PEDro scale.Pooled effect sizes(Hedges'g)were calculated via random-effects models,with heterogeneity quantified by I^(2).[Results]HIIT significantly improved peak oxygen uptake(VO_(2)peak)versus controls(g=0.59,95%CI:0.44-0.75,p<0.001;I^(2)=16.29%).Low heterogeneity and symmetrical funnel plots supported robustness.HIIT also enhanced walking endurance(6MWD:g=0.32,95%CI:0.16-0.48,p<0.01;I^(2)=30%).In contrast,no significant benefit was observed for balance function(BBS:g=0.07,95%CI:-0.13-0.26,p=0.50;I^(2)=0%).[Conclusions]HIIT is a safe and highly effective intervention for enhancing aerobic capacity and walking function post-stroke.Its benefits are maximized at higher intensities and longer durations but do not extend to balance improvement.Integrating HIIT into stroke rehabilitation protocols is strongly recommended to promote functional independence.展开更多
City Walk所倡导的城市漫游能够深入城市内部,触及街角社会空间,体察居民日常生活,其方式类似于城市地理学的实地调查,可视为从微观地理视角对城市内部空间结构的探究。在城市地理实践教学中,教师可引导学生开展有目的、有组织的City W...City Walk所倡导的城市漫游能够深入城市内部,触及街角社会空间,体察居民日常生活,其方式类似于城市地理学的实地调查,可视为从微观地理视角对城市内部空间结构的探究。在城市地理实践教学中,教师可引导学生开展有目的、有组织的City Walk活动,通过科学设计行走路线,将原本随意、无意识的漫步转化为系统性、目标导向的空间探索。尤其针对城市文化空间,可结合新芝加哥学派的“场景理论”进行观察与解读,进而将区域认知、综合思维、地理实践力以及人地协调观等核心素养有机融入教学过程。展开更多
Walking is the basic locomotion pattern for bipedal robots.The walking pattern is widely generated using the linear inverted pendulum model.The linear inverted pendulum motion of each support period can be designed as...Walking is the basic locomotion pattern for bipedal robots.The walking pattern is widely generated using the linear inverted pendulum model.The linear inverted pendulum motion of each support period can be designed as a walk primitive to be connected to form a walking trajectory.A novel method of integrating double support phase into the walk primitive was proposed in this article.The method describes the generation of walking patterns using walk primitives with double support,specifically for lateral plane including walking in place,walking for lateral,and walking initiation,and for sagittal plane including fixed step length walking,variable step length walking,and walking initiation.Compared to walk primitives without double support phase,those with double support phase reduce the maximum speed required by the robot and eliminate the need to adjust foothold for achieving continuous speed.The performance of the proposed method is validated by simulations and experiments on Neubot,a position-controlled biped robot.展开更多
BACKGROUND Liver cirrhosis often leads to significant impairments in functional capacity,which are associated with disease severity and prognosis.Simple,reliable,and low-cost tests are essential to monitor these patie...BACKGROUND Liver cirrhosis often leads to significant impairments in functional capacity,which are associated with disease severity and prognosis.Simple,reliable,and low-cost tests are essential to monitor these patients in clinical practice.The 6-min walk test(6MWT)is widely used in other chronic conditions,but its measurement properties in cirrhosis remain underexplored.AIM To assess the reliability of the 6MWT in patients with liver cirrhosis(LC).METHODS This cross-sectional study was conducted at a teaching hospital in Juiz de Fora-Minas Gerais.Patients diagnosed with LC at any stage of the disease and under clinical follow-up were included.Patients with grade 2 or higher encephalopathy,respiratory,and/or musculoskeletal diseases or who did not understand the test were excluded.Initially,anamnesis and anthropometric evaluation were performed,followed by the 6MWT.After 24 h the test was repeated.Descriptive statistics were used to present the data.Continuous variables were tested for normality using the Shapiro-Wilk test.The reliability of the 6MWT was tested through Bland-Altman analysis,typical error of measurement,and intraclass correlation coefficient(ICC)as well as a one-sample t-test.A paired Student’s ttest was used to check for differences between means,and Pearson’s correlation coefficient was used to verify the relationship between the two moments[first 6MWT(6MWT-1)and second 6MWT(6MWT-2)].RESULTS The mean difference between 6MWT-2 and 6MWT-1 was-18.9 m;the lower limit of the Bland-Altman agreement was-83.5 m,and the upper limit was 45.7 m.One participant was excluded from further analyses for being outside these limits.The typical error of measurement was 18.9 m.The ICC showed excellent reliability between the two tests(ICC=0.97,95%confidence internal:0.90-0.99,P<0.001).The Student’s one-sample t-value was-2.35(P=0.03).The paired t-value was 2.35(P=0.03).Pearson’s correlation coefficient between the 6MWT-1 and 6MWT-2 was r=0.98(P=0.0001).CONCLUSION The 6MWT is a test with excellent reliability.It is safe,easy to administer,inexpensive,and can be introduced into routine practice without loss of diagnostic precision in estimating the functional capacity of patients with LC.展开更多
Background The redirected walking(RDW)method for multi-user collaboration requires maintaining the relative position between users in a virtual environment(VE)and physical environment(PE).A chasing game in a VE is a t...Background The redirected walking(RDW)method for multi-user collaboration requires maintaining the relative position between users in a virtual environment(VE)and physical environment(PE).A chasing game in a VE is a typical virtual reality game that entails multi-user collaboration.When a user approaches and interacts with a target user in the VE,the user is expected to approach and interact with the target user in the corresponding PE as well.Existing methods of multi-user RDW mainly focus on obstacle avoidance,which does not account for the relative positional relationship between the users in both VE and PE.Methods To enhance the user experience and facilitate potential interaction,this paper presents a novel dynamic alignment algorithm for multi-user collaborative redirected walking(DA-RDW)in a shared PE where the target user and other users are moving.This algorithm adopts improved artificial potential fields,where the repulsive force is a function of the relative position and velocity of the user with respect to dynamic obstacles.For the best alignment,this algorithm sets the alignment-guidance force in several cases and then converts it into a constrained optimization problem to obtain the optimal direction.Moreover,this algorithm introduces a potential interaction object selection strategy for a dynamically uncertain environment to speed up the subsequent alignment.To balance obstacle avoidance and alignment,this algorithm uses the dynamic weightings of the virtual and physical distances between users and the target to determine the resultant force vector.Results The efficacy of the proposed method was evaluated using a series of simulations and live-user experiments.The experimental results demonstrate that our novel dynamic alignment method for multi-user collaborative redirected walking can reduce the distance error in both VE and PE to improve alignment with fewer collisions.展开更多
The successful application of perimeter control of urban traffic system strongly depends on the macroscopic fundamental diagram of the targeted region.Despite intensive studies on the partitioning of urban road networ...The successful application of perimeter control of urban traffic system strongly depends on the macroscopic fundamental diagram of the targeted region.Despite intensive studies on the partitioning of urban road networks,the dynamic partitioning of urban regions reflecting the propagation of congestion remains an open question.This paper proposes to partition the network into homogeneous sub-regions based on random walk algorithm.Starting from selected random walkers,the road network is partitioned from the early morning when congestion emerges.A modified Akaike information criterion is defined to find the optimal number of partitions.Region boundary adjustment algorithms are adopted to optimize the partitioning results to further ensure the correlation of partitions.The traffic data of Melbourne city are used to verify the effectiveness of the proposed partitioning method.展开更多
Random walk algorithms are crucial for sampling and approximation problems in statistical physics and theoretical computer science.The mixing property is necessary for Markov chains to approach stationary distribution...Random walk algorithms are crucial for sampling and approximation problems in statistical physics and theoretical computer science.The mixing property is necessary for Markov chains to approach stationary distributions and is facilitated by walks.Quantum walks show promise for faster mixing times than classical methods but lack universal proof,especially in finite group settings.Here,we investigate the continuous-time quantum walks on Cayley graphs of the dihedral group D_(2n)for odd n,generated by the smallest inverse closed symmetric subset.We present a significant finding that,in contrast to the classical mixing time on these Cayley graphs,which typically takes at least orderΩ(n^(2)log(1/2∈)),the continuous-time quantum walk mixing time on D_(2n)is of order O(n(log n)^(5)log(1/∈)),achieving a quadratic improvement over the classical case.Our paper advances the general understanding of quantum walk mixing on Cayley graphs,highlighting the improved mixing time achieved by continuous-time quantum walks on D_(2n).This work has potential applications in algorithms for a class of sampling problems based on non-abelian groups.展开更多
文摘BACKGROUND:Hemiplegia,a prevalent stroke-related condition,is often studied for motor dysfunction;however,spasticity remains under-researched.Abnormal muscle tone significantly hinders hemiplegic patients’walking recovery.OBJECTIVE:To determine whether early suspension-protected training with a personal assistant machine for stroke patients enhances walking ability and prevents muscle spasms.METHODS:Thirty-two early-stage stroke patients from Shenzhen University General Hospital and the China Rehabilitation Research Center were randomly assigned to the experimental group(n=16)and the control group(n=16).Both groups underwent 4 weeks of gait training under the suspension protection system for 30 minutes daily,5 days a week.The experimental group used the personal assistant machine during training.Three-dimensional gait analysis(using the Cortex motion capture system),Brunnstrom staging,Fugl-Meyer Assessment for lower limb motor function,Fugl-Meyer balance function,and the modified Ashworth Scale were evaluated within 1 week before the intervention and after 4 weeks of intervention.RESULTS AND CONCLUSION:After the 4-week intervention,all outcome measures showed significant changes in each group.The experimental group had a small but significant increase in the modified Ashworth Scale score(P<0.05,d=|0.15|),while the control group had a large significant increase(P<0.05,d=|1.48|).The experimental group demonstrated greater improvements in walking speed(16.5 to 38.44 cm/s,P<0.05,d=|4.01|),step frequency(46.44 to 64.94 steps/min,P<0.05,d=|2.32|),stride length(15.50 to 29.81 cm,P<0.05,d=|3.44|),and peak hip and knee flexion(d=|1.82|to|2.17|).After treatment,the experimental group showed significantly greater improvements than the control group in walking speed(38.44 vs.26.63 cm/s,P<0.05,d=|2.75|),stride length,peak hip and knee flexion(d=|1.31|to|1.45|),step frequency(64.94 vs.59.38 steps/min,P<0.05,d=|0.85|),and a reduced support phase(bilateral:24.31%vs.28.38%,P<0.05,d=|0.88|;non-paretic:66.19%vs.70.13%,P<0.05,d=|0.94|).For early hemiplegia,personal assistant machine-assisted gait training under the suspension protection system helps establish a correct gait pattern,prevents muscle spasms,and improves motor function.
基金supported by the National Natural Science Foundation of China(Grant No.11671145)the Science and Technology Commission of Shanghai Municipality(Grant No.18dz2271000).
文摘In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].
文摘The no-cloning theorem has sparked considerable interest in achieving high-fidelity approximate quantum cloning.Most of the previous studies mainly focused on the cloning of single particle states,and cloning schemes used there are incapable of cloning quantum entangled states in multipartite systems.Few schemes were proposed for cloning multiparticle states,which consume more entanglement resources with loss of qubits,and the fidelity of the cloned state is relatively low.In this paper,cloning schemes for bipartite and tripartite entangled states based on photonic quantum walk and entanglement swapping are proposed.The results show that according to the proposed schemes,two high-fidelity(up to 0.75)cloned states can be obtained with less quantum resource consumption.Because of the simple cloning steps,few quantum resources and high fidelity,these schemes are both efficient and feasible.Moreover,this cloning machine eliminates the need for tracing out cloning machine,thereby minimizing resource waste.
文摘Missiles provide long-range precision strike capabilities and have become a cornerstone of modern warfare.The contrail clouds formed by missile during their active flight phase present significant chal-lenges to high-altitude environmental observation and target detection and tracking.Existing studies primarily focus on specific airspace regions,leaving critical gaps in understanding the effects of long dispersion times,wide altitude ranges,and variable atmospheric conditions on missile contrail clouds.To address these gaps,this article develops a numerical method based on the Lagrangian random walk model,which incorporates various velocity variation terms,including particle velocity caused by the difference of wind field,by the thermal motion of local gas molecules and by random collisions between contrail cloud particles to capture the influence of environmental wind fields,atmospheric conditions,and particle concentrations on the motion of contrail cloud particles.A general coordinate system aligned with the missile's flight trajectory is employed to represent particle distribution characteristics.The proposed method is in good agreement with the conducted experiments as well as with the available numerical simulations.The results demonstrate that the proposed model effectively simulates the dispersion state of contrail clouds,accurately reflecting the impact of large-scale wind field variations and altitude changes with high computational efficiency.Additionally,simulation results indicate that the increased distance between gas molecules in rarefied environments facilitates enhanced particle dispersion,while larger particles exhibit a faster dispersion rate due to their greater mass.
文摘[Objectives]To synthesize evidence on HIIT versus moderate-intensity continuous training(MICT)or routine rehabilitation in stroke survivors.[Methods]We systematically searched 8 databases(PubMed,EMBASE,CENTRAL,Web of Science,SPORTSDiscus,PsycINFO,SCOPUS,CINAHL)up to May 2025.Seventeen randomized controlled trials(RCTs;total n=1142)met inclusion criteria:adults with stroke,device-based HIIT(≥70%HRR/VO 2peak),and outcomes assessing VO_(2)peak,6-min walk distance(6MWD),or Berg Balance Scale(BBS).Methodological quality was evaluated using the PEDro scale.Pooled effect sizes(Hedges'g)were calculated via random-effects models,with heterogeneity quantified by I^(2).[Results]HIIT significantly improved peak oxygen uptake(VO_(2)peak)versus controls(g=0.59,95%CI:0.44-0.75,p<0.001;I^(2)=16.29%).Low heterogeneity and symmetrical funnel plots supported robustness.HIIT also enhanced walking endurance(6MWD:g=0.32,95%CI:0.16-0.48,p<0.01;I^(2)=30%).In contrast,no significant benefit was observed for balance function(BBS:g=0.07,95%CI:-0.13-0.26,p=0.50;I^(2)=0%).[Conclusions]HIIT is a safe and highly effective intervention for enhancing aerobic capacity and walking function post-stroke.Its benefits are maximized at higher intensities and longer durations but do not extend to balance improvement.Integrating HIIT into stroke rehabilitation protocols is strongly recommended to promote functional independence.
基金supported in part by the National Key R&D Program under Grant 2018YFB1304504.
文摘Walking is the basic locomotion pattern for bipedal robots.The walking pattern is widely generated using the linear inverted pendulum model.The linear inverted pendulum motion of each support period can be designed as a walk primitive to be connected to form a walking trajectory.A novel method of integrating double support phase into the walk primitive was proposed in this article.The method describes the generation of walking patterns using walk primitives with double support,specifically for lateral plane including walking in place,walking for lateral,and walking initiation,and for sagittal plane including fixed step length walking,variable step length walking,and walking initiation.Compared to walk primitives without double support phase,those with double support phase reduce the maximum speed required by the robot and eliminate the need to adjust foothold for achieving continuous speed.The performance of the proposed method is validated by simulations and experiments on Neubot,a position-controlled biped robot.
文摘BACKGROUND Liver cirrhosis often leads to significant impairments in functional capacity,which are associated with disease severity and prognosis.Simple,reliable,and low-cost tests are essential to monitor these patients in clinical practice.The 6-min walk test(6MWT)is widely used in other chronic conditions,but its measurement properties in cirrhosis remain underexplored.AIM To assess the reliability of the 6MWT in patients with liver cirrhosis(LC).METHODS This cross-sectional study was conducted at a teaching hospital in Juiz de Fora-Minas Gerais.Patients diagnosed with LC at any stage of the disease and under clinical follow-up were included.Patients with grade 2 or higher encephalopathy,respiratory,and/or musculoskeletal diseases or who did not understand the test were excluded.Initially,anamnesis and anthropometric evaluation were performed,followed by the 6MWT.After 24 h the test was repeated.Descriptive statistics were used to present the data.Continuous variables were tested for normality using the Shapiro-Wilk test.The reliability of the 6MWT was tested through Bland-Altman analysis,typical error of measurement,and intraclass correlation coefficient(ICC)as well as a one-sample t-test.A paired Student’s ttest was used to check for differences between means,and Pearson’s correlation coefficient was used to verify the relationship between the two moments[first 6MWT(6MWT-1)and second 6MWT(6MWT-2)].RESULTS The mean difference between 6MWT-2 and 6MWT-1 was-18.9 m;the lower limit of the Bland-Altman agreement was-83.5 m,and the upper limit was 45.7 m.One participant was excluded from further analyses for being outside these limits.The typical error of measurement was 18.9 m.The ICC showed excellent reliability between the two tests(ICC=0.97,95%confidence internal:0.90-0.99,P<0.001).The Student’s one-sample t-value was-2.35(P=0.03).The paired t-value was 2.35(P=0.03).Pearson’s correlation coefficient between the 6MWT-1 and 6MWT-2 was r=0.98(P=0.0001).CONCLUSION The 6MWT is a test with excellent reliability.It is safe,easy to administer,inexpensive,and can be introduced into routine practice without loss of diagnostic precision in estimating the functional capacity of patients with LC.
基金Supported by STI 2030 Major Projects of China(2021ZD0200400).
文摘Background The redirected walking(RDW)method for multi-user collaboration requires maintaining the relative position between users in a virtual environment(VE)and physical environment(PE).A chasing game in a VE is a typical virtual reality game that entails multi-user collaboration.When a user approaches and interacts with a target user in the VE,the user is expected to approach and interact with the target user in the corresponding PE as well.Existing methods of multi-user RDW mainly focus on obstacle avoidance,which does not account for the relative positional relationship between the users in both VE and PE.Methods To enhance the user experience and facilitate potential interaction,this paper presents a novel dynamic alignment algorithm for multi-user collaborative redirected walking(DA-RDW)in a shared PE where the target user and other users are moving.This algorithm adopts improved artificial potential fields,where the repulsive force is a function of the relative position and velocity of the user with respect to dynamic obstacles.For the best alignment,this algorithm sets the alignment-guidance force in several cases and then converts it into a constrained optimization problem to obtain the optimal direction.Moreover,this algorithm introduces a potential interaction object selection strategy for a dynamically uncertain environment to speed up the subsequent alignment.To balance obstacle avoidance and alignment,this algorithm uses the dynamic weightings of the virtual and physical distances between users and the target to determine the resultant force vector.Results The efficacy of the proposed method was evaluated using a series of simulations and live-user experiments.The experimental results demonstrate that our novel dynamic alignment method for multi-user collaborative redirected walking can reduce the distance error in both VE and PE to improve alignment with fewer collisions.
基金Project supported by the National Natural Science Foundation of China(Grant No.12072340)the Chinese Scholarship Council and the Australia Research Council through a linkage project fund。
文摘The successful application of perimeter control of urban traffic system strongly depends on the macroscopic fundamental diagram of the targeted region.Despite intensive studies on the partitioning of urban road networks,the dynamic partitioning of urban regions reflecting the propagation of congestion remains an open question.This paper proposes to partition the network into homogeneous sub-regions based on random walk algorithm.Starting from selected random walkers,the road network is partitioned from the early morning when congestion emerges.A modified Akaike information criterion is defined to find the optimal number of partitions.Region boundary adjustment algorithms are adopted to optimize the partitioning results to further ensure the correlation of partitions.The traffic data of Melbourne city are used to verify the effectiveness of the proposed partitioning method.
基金supported by the Key-Area Research and Development Program of Guang-Dong Province(Grant No.2018B030326001)the National Natural Science Foundation of China(U1801661)Shenzhen Science and Technology Program(KQTD20200820113010023)。
文摘Random walk algorithms are crucial for sampling and approximation problems in statistical physics and theoretical computer science.The mixing property is necessary for Markov chains to approach stationary distributions and is facilitated by walks.Quantum walks show promise for faster mixing times than classical methods but lack universal proof,especially in finite group settings.Here,we investigate the continuous-time quantum walks on Cayley graphs of the dihedral group D_(2n)for odd n,generated by the smallest inverse closed symmetric subset.We present a significant finding that,in contrast to the classical mixing time on these Cayley graphs,which typically takes at least orderΩ(n^(2)log(1/2∈)),the continuous-time quantum walk mixing time on D_(2n)is of order O(n(log n)^(5)log(1/∈)),achieving a quadratic improvement over the classical case.Our paper advances the general understanding of quantum walk mixing on Cayley graphs,highlighting the improved mixing time achieved by continuous-time quantum walks on D_(2n).This work has potential applications in algorithms for a class of sampling problems based on non-abelian groups.
