The node-based smoothed finite element method(NS-FEM)is shortly presented for calculations of the static and seismic bearing capacities of shallow strip footings.A series of computations has been performed to assess v...The node-based smoothed finite element method(NS-FEM)is shortly presented for calculations of the static and seismic bearing capacities of shallow strip footings.A series of computations has been performed to assess variations in seismic bearing capacity factors with both horizontal and vertical seismic accelerations.Numerical results obtained agree very well with those using the slip-line method,revealing that the magnitude of the seismic bearing capacity is highly dependent upon the combinations of various directions of both components of the seismic acceleration.An upward vertical seismic acceleration reduces the seismic bearing capacity compared to the downward vertical seismic acceleration in calculations.In addition,particular emphasis is placed on a separate estimation of the effects of soil and superstructure inertia on each seismic bearing capacity component.While the effect of inertia forces arising in the soil on the seismic bearing capacity is non-trivial,and the superstructure inertia is the major contributor to reductions in the seismic bearing capacity.Both tables and charts are given for practical application to the seismic design of the foundations.展开更多
A Coupling Magneto-Electro-Elastic(MEE)Node-based Smoothed Radial Point Interpolation Method(CM-NS-RPIM)was proposed to solve the free vibration and transient responses of Functionally Graded Magneto-Electro-Elastic(F...A Coupling Magneto-Electro-Elastic(MEE)Node-based Smoothed Radial Point Interpolation Method(CM-NS-RPIM)was proposed to solve the free vibration and transient responses of Functionally Graded Magneto-Electro-Elastic(FGMEE)structures.By introducing the modified Newmark method,the displacement,electrical potential and magnetic potential of the structures under transient mechanical loading were obtained.Based on G space theory and the weakened weak(W2)formulation,the equations of the multi-physics coupling problems were derived.Using triangular background elements,the free vibration and transient responses of three numerical examples were studied.Results proved that CM-NS-RPIM performed better than the standard FEM by reducing the overly-stiff of structures.Moreover,CM-NS-RPIM could reduce the number of nodes while guaranteeing the accuracy.Besides,triangular elements could be generated automatically even for complex geometries.Therefore,the effectiveness and validity of CM-NS-RPIM were demonstrated,which were valuable for the design of intelligence devices,such as energy harvesters and sensors.展开更多
The amount of volunteered geographic information(VGI)has increased over the past decade,and several studies have been conducted to evaluate the quality of VGI data.In this study,we evaluate the completeness of the roa...The amount of volunteered geographic information(VGI)has increased over the past decade,and several studies have been conducted to evaluate the quality of VGI data.In this study,we evaluate the completeness of the road network in the VGI data set OpenStreetMap(OSM).The evaluation is based on an accurate and efficient network-matching algorithm.The study begins with a comparison of the two main strategies for network matching:segment-based and nodebased matching.The comparison shows that the result quality is comparable for the two strategies,but the node-based result is considerably more computationally efficient.Therefore,we improve the accuracy of node-based algorithm by handling topological relationships and detecting patterns of complicated network components.Finally,we conduct a case study on the extended node-based algorithm in which we match OSM to the Swedish National Road Database(NVDB)in Scania,Sweden.The case study reveals that OSM has a completeness of 87%in the urban areas and 69%in the rural areas of Scania.The accuracy of the matching process is approximately 95%.The conclusion is that the extended node-based algorithm is sufficiently accurate and efficient for conducting surveys of the quality of OSM and other VGI road data sets in large geographic regions.展开更多
无线传感器网络(WSNs)的运行效果对保证网络定位精度具有重要的意义。由于网络定位信息数据均可由自组网内节点随机获取,网络定位适用性在先验式路由协议链路状态路由协议(Optimized Link State Routing,OLSR)下表现更好。为了解决OLSR...无线传感器网络(WSNs)的运行效果对保证网络定位精度具有重要的意义。由于网络定位信息数据均可由自组网内节点随机获取,网络定位适用性在先验式路由协议链路状态路由协议(Optimized Link State Routing,OLSR)下表现更好。为了解决OLSR的多点中继(Multpoint Relays,MPR)节点运动速度较快的问题,为此设计了一种基于能量消耗的网络定位OLSR路由协议MPR机制评估方法,并开展仿真分析。研究结果表明:与原协议相比,节点能量消耗MPR选举生成协议表现出的性能更佳,经能量消耗MPR后形成的协议的吞吐量更大,有利于促进网络运行稳定性的提高。展开更多
优化链路状态路由(Optimized Link State Routing,OLSR)协议采用多点中继(Multi Point Relays,MPR)机制以减轻网络负载。然而,当传统MPR算法的最大覆盖度原则出现遗漏时,所选出的MPR集合并非最佳,无法达到最大程度的资源优化。为提升协...优化链路状态路由(Optimized Link State Routing,OLSR)协议采用多点中继(Multi Point Relays,MPR)机制以减轻网络负载。然而,当传统MPR算法的最大覆盖度原则出现遗漏时,所选出的MPR集合并非最佳,无法达到最大程度的资源优化。为提升协议在大规模网络中的表现,提出了两种改进方案来优化传统MPR算法:一种是基于果蝇思想的MPR方案(FruitFly MPR,FF-MPR),另一种是基于逆向贪心策略的MPR方案(Backward Greed MPR,BG-MPR)。Matlab仿真结果显示,这两种方案都有效规避了传统MPR算法的冗余问题。但是,FF-MPR因其固有的随机性和较长的计算时间而不适合节点多、移动性强的网络环境;BG-MPR在特殊情况下可能会产生新的冗余问题。为此,对BG-MPR中新产生的冗余进行了深入研究,提出了相应的解决措施,开发出基于改进逆向贪心策略的OLSR协议(Reverse Greed OLSR,RG-OLSR),使用OPNET仿真平台对其进行了测试。仿真结果证明,RG-OLSR在控制消息开销、端到端时延和时延抖动等关键性能指标上均优于传统的OLSR协议。展开更多
基金part of the TPS projecta Vied-Newton PhD scholarship+1 种基金a Dixon scholarship from Imperial College London,UKthe Dean’s Fund from Imperial College London for financial support(2017-2020)。
文摘The node-based smoothed finite element method(NS-FEM)is shortly presented for calculations of the static and seismic bearing capacities of shallow strip footings.A series of computations has been performed to assess variations in seismic bearing capacity factors with both horizontal and vertical seismic accelerations.Numerical results obtained agree very well with those using the slip-line method,revealing that the magnitude of the seismic bearing capacity is highly dependent upon the combinations of various directions of both components of the seismic acceleration.An upward vertical seismic acceleration reduces the seismic bearing capacity compared to the downward vertical seismic acceleration in calculations.In addition,particular emphasis is placed on a separate estimation of the effects of soil and superstructure inertia on each seismic bearing capacity component.While the effect of inertia forces arising in the soil on the seismic bearing capacity is non-trivial,and the superstructure inertia is the major contributor to reductions in the seismic bearing capacity.Both tables and charts are given for practical application to the seismic design of the foundations.
基金co-supported by the National Key R&D Program of China(Nos.2018YFF01012401-05)the National Natural Science Foundation of China(No.51975243)+2 种基金Jilin Provincial Department of Education(No.JJKH20180084KJ),Chinathe Fundamental Research Funds for the Central Universities and Jilin Provincial Department of Science&Technology Fund Project,China(Nos.20170101043JC and 20180520072JH)Graduate Innovation Fund of Jilin University,China(No.101832018C184).
文摘A Coupling Magneto-Electro-Elastic(MEE)Node-based Smoothed Radial Point Interpolation Method(CM-NS-RPIM)was proposed to solve the free vibration and transient responses of Functionally Graded Magneto-Electro-Elastic(FGMEE)structures.By introducing the modified Newmark method,the displacement,electrical potential and magnetic potential of the structures under transient mechanical loading were obtained.Based on G space theory and the weakened weak(W2)formulation,the equations of the multi-physics coupling problems were derived.Using triangular background elements,the free vibration and transient responses of three numerical examples were studied.Results proved that CM-NS-RPIM performed better than the standard FEM by reducing the overly-stiff of structures.Moreover,CM-NS-RPIM could reduce the number of nodes while guaranteeing the accuracy.Besides,triangular elements could be generated automatically even for complex geometries.Therefore,the effectiveness and validity of CM-NS-RPIM were demonstrated,which were valuable for the design of intelligence devices,such as energy harvesters and sensors.
文摘The amount of volunteered geographic information(VGI)has increased over the past decade,and several studies have been conducted to evaluate the quality of VGI data.In this study,we evaluate the completeness of the road network in the VGI data set OpenStreetMap(OSM).The evaluation is based on an accurate and efficient network-matching algorithm.The study begins with a comparison of the two main strategies for network matching:segment-based and nodebased matching.The comparison shows that the result quality is comparable for the two strategies,but the node-based result is considerably more computationally efficient.Therefore,we improve the accuracy of node-based algorithm by handling topological relationships and detecting patterns of complicated network components.Finally,we conduct a case study on the extended node-based algorithm in which we match OSM to the Swedish National Road Database(NVDB)in Scania,Sweden.The case study reveals that OSM has a completeness of 87%in the urban areas and 69%in the rural areas of Scania.The accuracy of the matching process is approximately 95%.The conclusion is that the extended node-based algorithm is sufficiently accurate and efficient for conducting surveys of the quality of OSM and other VGI road data sets in large geographic regions.
文摘无线传感器网络(WSNs)的运行效果对保证网络定位精度具有重要的意义。由于网络定位信息数据均可由自组网内节点随机获取,网络定位适用性在先验式路由协议链路状态路由协议(Optimized Link State Routing,OLSR)下表现更好。为了解决OLSR的多点中继(Multpoint Relays,MPR)节点运动速度较快的问题,为此设计了一种基于能量消耗的网络定位OLSR路由协议MPR机制评估方法,并开展仿真分析。研究结果表明:与原协议相比,节点能量消耗MPR选举生成协议表现出的性能更佳,经能量消耗MPR后形成的协议的吞吐量更大,有利于促进网络运行稳定性的提高。
文摘优化链路状态路由(Optimized Link State Routing,OLSR)协议采用多点中继(Multi Point Relays,MPR)机制以减轻网络负载。然而,当传统MPR算法的最大覆盖度原则出现遗漏时,所选出的MPR集合并非最佳,无法达到最大程度的资源优化。为提升协议在大规模网络中的表现,提出了两种改进方案来优化传统MPR算法:一种是基于果蝇思想的MPR方案(FruitFly MPR,FF-MPR),另一种是基于逆向贪心策略的MPR方案(Backward Greed MPR,BG-MPR)。Matlab仿真结果显示,这两种方案都有效规避了传统MPR算法的冗余问题。但是,FF-MPR因其固有的随机性和较长的计算时间而不适合节点多、移动性强的网络环境;BG-MPR在特殊情况下可能会产生新的冗余问题。为此,对BG-MPR中新产生的冗余进行了深入研究,提出了相应的解决措施,开发出基于改进逆向贪心策略的OLSR协议(Reverse Greed OLSR,RG-OLSR),使用OPNET仿真平台对其进行了测试。仿真结果证明,RG-OLSR在控制消息开销、端到端时延和时延抖动等关键性能指标上均优于传统的OLSR协议。
