The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calcula...The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calculated using the state-of-the-art space-time separation principle that separates the Emergency Braking(EB)trajectories of two successive units during the whole EB process.In this case,the minimal safety distance is usually numerically calculated without an analytic formulation.Thus,the constrained VCTS control problem is hard to address with space-time separation,which is still a gap in the existing literature.To solve this problem,we propose a Distributed Economic Model Predictive Control(DEMPC)approach with computation efficiency and theoretical guarantee.Specifically,to alleviate the computation burden,we transform implicit safety constraints into explicitly linear ones,such that the optimal control problem in DEMPC is a quadratic programming problem that can be solved efficiently.For theoretical analysis,sufficient conditions are derived to guarantee the recursive feasibility and stability of DEMPC,employing compatibility constraints,tube techniques and terminal ingredient tuning.Moreover,we extend our approach with globally optimal and distributed online EB configuration methods to shorten the minimal distance among VCTS.Finally,experimental results demonstrate the performance and advantages of the proposed approaches.展开更多
A new efficient adapting virtual intermediate instruction set,V-IIS,is designed and implemented towards the optimized dynamic binary translator (DBT) system.With the help of this powerful but previously little-studied...A new efficient adapting virtual intermediate instruction set,V-IIS,is designed and implemented towards the optimized dynamic binary translator (DBT) system.With the help of this powerful but previously little-studied component,DBTs can not only get rid of the dependence of machine(s),but also get better performance.From our systematical study and evaluation,experimental results demonstrate that if V-IIS is well designed,without affecting the other optimizing measures,this could make DBT's performance close to those who do not have intermediate instructions.This study is an important step towards the grand goal of high performance "multi-source" and "multi-target" dynamic binary translation.展开更多
Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) an...Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.展开更多
基于3~6岁学龄前132个男童的测量数据,分析得出三类体型,确定研究对象为最普遍的第2类正常体型;以第2类正常体男童的基本裤型为例,利用CLO3D进行虚拟仿真试验,结合髋关节、膝关节活动范围确定五种动态模拟,进行不同动态下基本裤型的虚...基于3~6岁学龄前132个男童的测量数据,分析得出三类体型,确定研究对象为最普遍的第2类正常体型;以第2类正常体男童的基本裤型为例,利用CLO3D进行虚拟仿真试验,结合髋关节、膝关节活动范围确定五种动态模拟,进行不同动态下基本裤型的虚拟压力和虚拟应力探究。结果显示:髋、膝关节角度较大时,后臀部位的B2点以及膝盖部位的F5点等虚拟压力和应力也较大;由于面料拉伸,大腿外侧的S2、S3点有较大的应力以及较小的压力,而膝盖以下几乎没有服装虚拟压力和应力。在此基础上进行版型优化,优化效果最好的是B2点,其平均虚拟压力和应力分别下降了5.59 k Pa和8.73%;使用汗布、毛圈布、珠地布三种针织面料进行模拟试穿,以及真人试穿测试,进一步验证了版型优化的有效性。展开更多
基金supported by the National Natural Science Foundation of China(52372310)the State Key Laboratory of Advanced Rail Autonomous Operation(RAO2023ZZ001)+1 种基金the Fundamental Research Funds for the Central Universities(2022JBQY001)Beijing Laboratory of Urban Rail Transit.
文摘The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calculated using the state-of-the-art space-time separation principle that separates the Emergency Braking(EB)trajectories of two successive units during the whole EB process.In this case,the minimal safety distance is usually numerically calculated without an analytic formulation.Thus,the constrained VCTS control problem is hard to address with space-time separation,which is still a gap in the existing literature.To solve this problem,we propose a Distributed Economic Model Predictive Control(DEMPC)approach with computation efficiency and theoretical guarantee.Specifically,to alleviate the computation burden,we transform implicit safety constraints into explicitly linear ones,such that the optimal control problem in DEMPC is a quadratic programming problem that can be solved efficiently.For theoretical analysis,sufficient conditions are derived to guarantee the recursive feasibility and stability of DEMPC,employing compatibility constraints,tube techniques and terminal ingredient tuning.Moreover,we extend our approach with globally optimal and distributed online EB configuration methods to shorten the minimal distance among VCTS.Finally,experimental results demonstrate the performance and advantages of the proposed approaches.
基金Projects(12R21414600)supported by Shanghai Municipal Science and Technology Commission,China
文摘A new efficient adapting virtual intermediate instruction set,V-IIS,is designed and implemented towards the optimized dynamic binary translator (DBT) system.With the help of this powerful but previously little-studied component,DBTs can not only get rid of the dependence of machine(s),but also get better performance.From our systematical study and evaluation,experimental results demonstrate that if V-IIS is well designed,without affecting the other optimizing measures,this could make DBT's performance close to those who do not have intermediate instructions.This study is an important step towards the grand goal of high performance "multi-source" and "multi-target" dynamic binary translation.
文摘Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.
文摘基于3~6岁学龄前132个男童的测量数据,分析得出三类体型,确定研究对象为最普遍的第2类正常体型;以第2类正常体男童的基本裤型为例,利用CLO3D进行虚拟仿真试验,结合髋关节、膝关节活动范围确定五种动态模拟,进行不同动态下基本裤型的虚拟压力和虚拟应力探究。结果显示:髋、膝关节角度较大时,后臀部位的B2点以及膝盖部位的F5点等虚拟压力和应力也较大;由于面料拉伸,大腿外侧的S2、S3点有较大的应力以及较小的压力,而膝盖以下几乎没有服装虚拟压力和应力。在此基础上进行版型优化,优化效果最好的是B2点,其平均虚拟压力和应力分别下降了5.59 k Pa和8.73%;使用汗布、毛圈布、珠地布三种针织面料进行模拟试穿,以及真人试穿测试,进一步验证了版型优化的有效性。
