Heavy routing overhead in Mobile Ad hoc Network(MANET)is a main bottleneck limiting the network performance.In this paper,we propose a novel Clustering OLSR(C-OLSR)approach,which utilizes two schemes,i.e.,clustering a...Heavy routing overhead in Mobile Ad hoc Network(MANET)is a main bottleneck limiting the network performance.In this paper,we propose a novel Clustering OLSR(C-OLSR)approach,which utilizes two schemes,i.e.,clustering and optimized Topology Control(TC)message transfer to reduce the control overhead of OLSR while guaranteeing its realtime requirement.To reduce the control overhead,in C-LOSR,flooding of TC messages is only limited in the cluster.All TC messages are integrated into a Cluster Topology Control(CTC)message by the cluster header and broadcast over the network.To satisfy the real-time requirement,any topology change will trigger CTC messages over the network.Extensive simulations have been done to evaluate the performance of the proposed C-OLSR.Results show that C-OLSR can achieve lower control overhead than OLSR by 44.32%in static networks and by 23.21%in dynamic networks.展开更多
Optimizing Flow Path Design(FPD)is a popular research area in transportation system design,but its application to Overhead Transportation Systems(OTSs)has been limited.This study focuses on optimizing a double-spine f...Optimizing Flow Path Design(FPD)is a popular research area in transportation system design,but its application to Overhead Transportation Systems(OTSs)has been limited.This study focuses on optimizing a double-spine flow path design for OTSs with 10 stations by minimizing the total travel distance for both loaded and empty flows.We employ transportation methods,specifically the North-West Corner and Stepping-Stone methods,to determine empty vehicle travel flows.Additionally,the Tabu Search(TS)algorithm is applied to branch the 10 stations into two main layout branches.The results obtained from our proposed method demonstrate a reduction in the objective function value compared to the initial feasible solution.Furthermore,we explore howchanges in the parameters of the TS algorithm affect the optimal result.We validate the feasibility of our approach by comparing it with relevant literature and conducting additional tests on layouts with 20 and 30 stations.展开更多
文摘Heavy routing overhead in Mobile Ad hoc Network(MANET)is a main bottleneck limiting the network performance.In this paper,we propose a novel Clustering OLSR(C-OLSR)approach,which utilizes two schemes,i.e.,clustering and optimized Topology Control(TC)message transfer to reduce the control overhead of OLSR while guaranteeing its realtime requirement.To reduce the control overhead,in C-LOSR,flooding of TC messages is only limited in the cluster.All TC messages are integrated into a Cluster Topology Control(CTC)message by the cluster header and broadcast over the network.To satisfy the real-time requirement,any topology change will trigger CTC messages over the network.Extensive simulations have been done to evaluate the performance of the proposed C-OLSR.Results show that C-OLSR can achieve lower control overhead than OLSR by 44.32%in static networks and by 23.21%in dynamic networks.
基金funded by Ho Chi Minh City University of Technology(HCMUT),VNU-HCM under Grant Number B2021-20-04.
文摘Optimizing Flow Path Design(FPD)is a popular research area in transportation system design,but its application to Overhead Transportation Systems(OTSs)has been limited.This study focuses on optimizing a double-spine flow path design for OTSs with 10 stations by minimizing the total travel distance for both loaded and empty flows.We employ transportation methods,specifically the North-West Corner and Stepping-Stone methods,to determine empty vehicle travel flows.Additionally,the Tabu Search(TS)algorithm is applied to branch the 10 stations into two main layout branches.The results obtained from our proposed method demonstrate a reduction in the objective function value compared to the initial feasible solution.Furthermore,we explore howchanges in the parameters of the TS algorithm affect the optimal result.We validate the feasibility of our approach by comparing it with relevant literature and conducting additional tests on layouts with 20 and 30 stations.
文摘研究受限空间内过头作业人员疲劳特征,以避免疲劳累积和降低事故风险。设计了典型受限空间内过头作业试验,测量20名被试在不同受限空间高度(120 cm、140 cm)和不同工作面(侧面、顶面、正面)下的表面肌电(Surface Electromyogram,sEMG)信号和心率变异性(Heart Rate Variability,HRV)信号,记录主观疲劳评分,并对数据进行分析。结果表明:受限空间内过头作业疲劳累积明显;右肩膀和右前臂主观疲劳评分最高;左上斜方肌、右上斜方肌、右中三角肌、右冈上肌、右冈下肌和右肱桡肌中位频率(Median Frequency,MF)下降显著,右中三角肌MF下降幅度最大;相邻RR间期均值(RR mean)降低,低频成分(Low Frequency,LF)和低频高频比值(Ratio of Low Frequency to High Frequency,LF/HF)均上升;与120 cm高度相比,140 cm高度下全身及5个身体部位主观疲劳评分更高,6个肌群MF下降斜率更大,RR mean下降幅度以及LF、LF/HF上升幅度更大;工作面对主观疲劳评分、各肌群MF及HRV指标影响不显著,但正面工作面除右肱桡肌外5个肌群均疲劳累积显著,侧面和顶面工作面右上斜方肌、右中三角肌和右冈上肌3个肌群疲劳累积显著。
文摘水声网络(underwater acoustic network,UAN)具有长传播时延、高误码率、半双工通信等特性,这些特性严重影响了UAN中数据的可靠传输。而在线喷泉码具有在线控制、编解码复杂度低、码率自适应等诸多优势,在线喷泉码适合于保障UAN中数据的可靠传输。针对递归与限制反馈的在线喷泉码(recursive OFC with limited feedback,ROFC-LF)存在不理想覆盖和4元环问题导致略高的开销和频繁的反馈,提出适用于UAN的基于优先级与可Zigzag解码的ROFC-LF(priority-based and zigzag-decodable ROFC-LF,P-ZROFC-LF)。P-ZROFC-LF在建立阶段选取具有最高优先级的原始包进行编码直至所有原始包均参与编码。同时,引入可Zigzag解码编码,将无用编码包进行移位异或转换为有用编码包来提高解码性能。通过随机图理论,分析P-ZROFC-LF所需编码包数与原始包数之间的关系。理论分析与仿真结果表明,与大部分在线喷泉码相比,P-ZROFC-LF显著提高了反馈和开销性能。其中P-ZROFC-LF相比于ROFC-LF的反馈和开销分别减少了18%和0.0176,更适用于UAN。
