Research on ad-hoc network connectivity has mainly focused on asymptotic results in the number of nodes in the network. For a one-dimensional ad-hoc network G1, assuming all the nodes are independently uniform distrib...Research on ad-hoc network connectivity has mainly focused on asymptotic results in the number of nodes in the network. For a one-dimensional ad-hoc network G1, assuming all the nodes are independently uniform distributed in a closed interval [0, Z]（z ∈ R^＋）, we derive a generic formula for the probability that the network is connected. The finite connected ad-hoc networks is analyzed. And we separately suggest necessary conditions to make the ad-hoc network to be connected in one and two dimensional cases, facing possible failed nodes （f-nodes）. Based on the necessary condition and unit-disk assumption for the node transmission, we prove that the nodes of the connected two-dimensional ad-hoc networks （G2） can be divided into at most five different groups. For an f-node no in either of the five groups, we derive a close formula for the probability that there is at least one route between a pair of nodes in G2 -- {no}.展开更多
Vehicles travelling as platoons can reduce the huge traffic jams on the highway. Platoon members can share vehicle information such as speed and acceleration via vehicular ad hoc networks （VANETs） communication to m...Vehicles travelling as platoons can reduce the huge traffic jams on the highway. Platoon members can share vehicle information such as speed and acceleration via vehicular ad hoc networks （VANETs） communication to maintain a constant inter-vehicle and inter-platoon distances. However, connectivity is a fundamental measurement to indicate the linking quality of VANETs. This paper analyzes the access and connectivity probability between the vehicles and the road side units （RSUs） of the multi-way platoon-based VANETs with roadside infrastructure. We denote the connectivity probability as the probability that the vehicles on the highway can access to at least one RSU besides the road within a designated number of hops. Moreover, besides considering the connection on the same road, we study the connection between the vehicles and the RSU via vehicles on the nearby neighbor roads. The analytical results have been validated by simulations and results show that the connectivity probability can be improved when there are platoons in a network. Meanwhile, the connectivity probability is higher in the multi-way vehicle-to-infrastructure （V2I） communication network than that in a one-way V2I communication network. The results in this paper can help to reduce the jams on the highway and achieve intelligent driving. Then the safety and comfort of the drivers and passengers on the highway can be improved. Moreover, these results can provide forceful theoretical support to the future intelligent transportation system （ITS） design.展开更多
The probability model is used to analyze the fault tolerance of mesh. To simplify its analysis, it is as-sumed that the failure probability of each node is independent. A 3-D mesh is partitioned into smaller submeshes...The probability model is used to analyze the fault tolerance of mesh. To simplify its analysis, it is as-sumed that the failure probability of each node is independent. A 3-D mesh is partitioned into smaller submeshes,and then the probability with which each submesh satisfies the defined condition is computed. If each submesh satis-fies the condition, then the whole mesh is connected. Consequently, the probability that a 3-D mesh is connected iscomputed assuming each node has a failure probability. Mathematical methods are used to derive a relationship be-tween network node failure probability and network connectivity probability. The calculated results show that the 3-D mesh networks can remain connected with very high probability in practice. It is formally proved that when thenetwork node failure probability is boutded by 0.45 %, the 3-D mesh networks of more than three hundred thousandnodes remain connected with probability larger than 99 %. The theoretical results show that the method is a power-ful technique to calculate the lower bound of the connectivity probability of mesh networks.展开更多
In Ad-hoc wireless network, connectivity is a fundamental issue which restricts the design of system protocol. Based on the theory of stochastic geometry, a connectivity model focused on signal-to-interference （SIR）...In Ad-hoc wireless network, connectivity is a fundamental issue which restricts the design of system protocol. Based on the theory of stochastic geometry, a connectivity model focused on signal-to-interference （SIR） ratio is set up in presence of Nakagami-m fading and interference. This paper derives a close formula of connectivity probability with interference and Nakagami-m fading which is never obtained in previous works. Two-dimension shot-noise theory in stochastic geometry for interference is well applied. The formula is verified by simulation. The results show that the connectivity is affected by the scatter of users, wireless propagation environment, interference and so on.展开更多
现实生活中的网络，如生物蛋白网络、无线传感器网络等都存在着很多不确定性，如何准确、快速地发现其中有效的信息具有特别重要的意义。由于发现前 K 个最紧密子图具有较高的复杂性并且实现条件较高，本文根据实际背景研究了从不确定...现实生活中的网络，如生物蛋白网络、无线传感器网络等都存在着很多不确定性，如何准确、快速地发现其中有效的信息具有特别重要的意义。由于发现前 K 个最紧密子图具有较高的复杂性并且实现条件较高，本文根据实际背景研究了从不确定图中发现存在概率较高的前 K 个紧密子图问题，分析不确定图的连通性和紧密子图存在概率，提出了不确定相对 K 紧密子图发现算法。在算法中，首先计算不确定图的连通指数，确定不确定阈值，根据不确定阈值计算子图存在概率，最终得到 K 个相对紧密子图。最后，通过若干组实验，验证了此算法可以高效、准确地发现不确定图中的紧密子图，能够解决生活中出现的各种问题。展开更多
利用2006年沈阳市Quick Bird遥感影像城市森林解译数据,借助地理信息系统,以沈阳市三环以内区域城市森林景观斑块为研究对象,基于生境可利用性和动植物的扩散能力,选取50、100、200、400、600、800、1000、1200 m 8个距离阈值,采用整体...利用2006年沈阳市Quick Bird遥感影像城市森林解译数据,借助地理信息系统,以沈阳市三环以内区域城市森林景观斑块为研究对象,基于生境可利用性和动植物的扩散能力,选取50、100、200、400、600、800、1000、1200 m 8个距离阈值,采用整体连通性指数、可能连通性指数和景观中各斑块的重要性对研究区城市森林景观连接度的距离阈值进行了分析和筛选.结果表明:2006年沈阳城市森林景观连接度的适宜距离阈值范围在100～400 m,以200 m尤为适宜.距离阈值的选择可因城市森林景观连通性的可执行性和不同层次需求而适当增大或减小.展开更多
基金the National Natural Science Foundation of China (Grant No. 60572066)Key Scientific Research Project of Shanghai Municipal Education Commission (Grant No. 06ZZ84)CityU, Hong Kong, Applied R & D Funding (ARD) (Grant No. 9668009)
文摘Research on ad-hoc network connectivity has mainly focused on asymptotic results in the number of nodes in the network. For a one-dimensional ad-hoc network G1, assuming all the nodes are independently uniform distributed in a closed interval [0, Z]（z ∈ R^＋）, we derive a generic formula for the probability that the network is connected. The finite connected ad-hoc networks is analyzed. And we separately suggest necessary conditions to make the ad-hoc network to be connected in one and two dimensional cases, facing possible failed nodes （f-nodes）. Based on the necessary condition and unit-disk assumption for the node transmission, we prove that the nodes of the connected two-dimensional ad-hoc networks （G2） can be divided into at most five different groups. For an f-node no in either of the five groups, we derive a close formula for the probability that there is at least one route between a pair of nodes in G2 -- {no}.
基金supported by the Application and Basic Research Project of Sichuan Province(2012JY0096)Fundamental Research Funds for the Central Universities of Southwest University for Nationalities(2016NZYQN23)
文摘Vehicles travelling as platoons can reduce the huge traffic jams on the highway. Platoon members can share vehicle information such as speed and acceleration via vehicular ad hoc networks （VANETs） communication to maintain a constant inter-vehicle and inter-platoon distances. However, connectivity is a fundamental measurement to indicate the linking quality of VANETs. This paper analyzes the access and connectivity probability between the vehicles and the road side units （RSUs） of the multi-way platoon-based VANETs with roadside infrastructure. We denote the connectivity probability as the probability that the vehicles on the highway can access to at least one RSU besides the road within a designated number of hops. Moreover, besides considering the connection on the same road, we study the connection between the vehicles and the RSU via vehicles on the nearby neighbor roads. The analytical results have been validated by simulations and results show that the connectivity probability can be improved when there are platoons in a network. Meanwhile, the connectivity probability is higher in the multi-way vehicle-to-infrastructure （V2I） communication network than that in a one-way V2I communication network. The results in this paper can help to reduce the jams on the highway and achieve intelligent driving. Then the safety and comfort of the drivers and passengers on the highway can be improved. Moreover, these results can provide forceful theoretical support to the future intelligent transportation system （ITS） design.
基金Project (69928201) supported by the National Science Fund for Distinguished Young Scholars+1 种基金project (90104028) by the National Natural Science Foundation of China Project by Changjiang Scholar Re-ward Project
文摘The probability model is used to analyze the fault tolerance of mesh. To simplify its analysis, it is as-sumed that the failure probability of each node is independent. A 3-D mesh is partitioned into smaller submeshes,and then the probability with which each submesh satisfies the defined condition is computed. If each submesh satis-fies the condition, then the whole mesh is connected. Consequently, the probability that a 3-D mesh is connected iscomputed assuming each node has a failure probability. Mathematical methods are used to derive a relationship be-tween network node failure probability and network connectivity probability. The calculated results show that the 3-D mesh networks can remain connected with very high probability in practice. It is formally proved that when thenetwork node failure probability is boutded by 0.45 %, the 3-D mesh networks of more than three hundred thousandnodes remain connected with probability larger than 99 %. The theoretical results show that the method is a power-ful technique to calculate the lower bound of the connectivity probability of mesh networks.
基金supported by the National Natural Science Foundation of China(61171094)National Science & Technology Key Project(2011ZX03001-006-02,2011ZX03005-004-03)+1 种基金the Key Project of Jiangsu Provincial Natural Science Foundation (BK2011027)the Graduate Student Innovation Plan of Jiangsu Province(CXZZ11_0387)
文摘In Ad-hoc wireless network, connectivity is a fundamental issue which restricts the design of system protocol. Based on the theory of stochastic geometry, a connectivity model focused on signal-to-interference （SIR） ratio is set up in presence of Nakagami-m fading and interference. This paper derives a close formula of connectivity probability with interference and Nakagami-m fading which is never obtained in previous works. Two-dimension shot-noise theory in stochastic geometry for interference is well applied. The formula is verified by simulation. The results show that the connectivity is affected by the scatter of users, wireless propagation environment, interference and so on.
文摘现实生活中的网络，如生物蛋白网络、无线传感器网络等都存在着很多不确定性，如何准确、快速地发现其中有效的信息具有特别重要的意义。由于发现前 K 个最紧密子图具有较高的复杂性并且实现条件较高，本文根据实际背景研究了从不确定图中发现存在概率较高的前 K 个紧密子图问题，分析不确定图的连通性和紧密子图存在概率，提出了不确定相对 K 紧密子图发现算法。在算法中，首先计算不确定图的连通指数，确定不确定阈值，根据不确定阈值计算子图存在概率，最终得到 K 个相对紧密子图。最后，通过若干组实验，验证了此算法可以高效、准确地发现不确定图中的紧密子图，能够解决生活中出现的各种问题。
