共查询到19条相似文献,搜索用时 375 毫秒
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本文以某广场的Portal定制页面无线网络建设为对象,对网络的逻辑拓扑、流量控制、Portal定制页面的无线网的认证和网络安全等方面分析该网络的建设过程,可以为国家会展中心智慧运营系统建设提供参考。 相似文献
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基于local-area的Internet路由级拓扑抽象算法 总被引:1,自引:0,他引:1
通过分析Internet的本地聚集特性,给出了local-area和connect-area的定义,并基于此,为提高并行网络模拟性能,提出一种新型拓扑抽象算法——基于local -area的拓扑抽象(TABLA)算法.TABLA算法在给定的聚合粒度下,迭代搜索网络内的local-area,对拓扑进行抽象.模拟结果表明在... 相似文献
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提出了一种能改进流量控制性能的算法,称为多比特拥塞指示算法。这种算法可以兼容ATM论坛提出的相对速率控制算法,在现有的相对速率标记交换机中一样可以很好地工作,不会产生不兼容的情况,通过仿真发现,多比特拥塞算法在性能上更加优越。 相似文献
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无线传感器网络的拓扑结构随着网络中节点的增加、减少和移动实时变化,为保证网络的连通性和覆盖性不被影响,拓扑控制技术所要解决的问题正是传感器节点如何更好地自组织构建全局网络拓扑.本文首先概述了四类拓扑控制算法的理论基础及算法步骤.然后,对提高网络抗毁性的两类拓扑演化算法进行了详细叙述,即无标度网络生长与构建$k$连通网络,分别构建了基于节点位置偏好的移动网络拓扑模型和基于$k$连通的节点调度优化模型.最后,分别从移动节点的引入、折中控制算法的探索、复杂网络理论的应用和传统算法与智能算法的结合这四方面对拓扑控制算法的前景进行了阐述. 相似文献
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介绍了蚁群算法的原理,然后对现有蚁群算法进行了一些改进,使它能够快速地收敛以满足高速变化的卫星网络拓扑结构.采用改进的虚拟拓扑策略解决了卫星网络拓扑高速变换的问题.将改进的蚁群算法应用于其上,并给出了相应的性能评估.所提出的改进的虚拟拓扑策略,能够大大减少一个系统周期内卫星网的时间片个数.应用于此基础上的改进的蚁群算法也体现了较好的性能. 相似文献
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许多领域都需要进行P2P数据流量的监控与分析,比如航天、医学、网络信息安全、网络性能优化、网络计费管理等。但由于因特网的接入者越来越多、网络数据流量不断增加,对网络数据流量的监控与分析的难度也在不断增大,已不像过去的基于端口那么简单。鉴于此,提出一个P2P网络数据流量分析的算法思想。该算法主要是根据其应用分类将流量分组,提高网络数据流量分析的准确性与可靠性。 相似文献
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受到可制造性的约束,拓扑优化技术目前多用于结构的概念设计,因此,研究直接面向加工制造的拓扑优化方法很有必要。该文基于启发式BESO(Bi-directional Evolutionary Structural Optimization)算法,提出了一种高效的可精确控制结构最小尺寸的拓扑优化方法。通过灵敏度插值,细化边界单元,改进BESO算法,解决边界不光滑问题;采用拓扑细化方法,提取拓扑结构的骨架构型;以此为基础,判定结构中不满足最小尺寸约束的部位,基于改进的BESO算法,实现拓扑优化结构的最小尺寸精确控制;此外,在优化过程中,通过松弛施加最小尺寸约束的方法,有效避免优化早熟问题。数值算例表明了该拓扑优化方法的有效性。 相似文献
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离散变量桁架结构拓扑优化设计的混合算法 总被引:1,自引:0,他引:1
将相对差商法和混沌优化结合起来,形成求解离散变量桁架结构拓扑优化设计的混合算法。利用相对差商法可以对离散变量快速寻优的特点,及混沌变量的全局遍历性,可以有效地跳出局部最优解,达到拓扑优化全局寻优的目的。通过采用和准最优解的对比及几何稳定性的判断等辅助性技术,降低了重分析次数。同时,高效的重分析方法的结合,提高了求解的效率,也避免了拓扑优化问题中求解的一些困难。算例表明,该算法对于离散变量的拓扑优化设计问题是快速有效的。 相似文献
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针对现有基于传输层特征的P2P识别方法的不足,分析了局域网环境下主流P2P应用的客户端口连接数、失败连接数、TCP/UDP服务端口连接数、所连接的远端IP数与远端端口数等传输层连接特征,根据P2P应用与普通Intemet应用在这些连接特征上的显著差异,提出了一种适用于局域网环境的实时P2P主机识别算法,并以该算法为核心,设计和实现了实时P2P应用监测系统traffMon.在实际网络环境中对traffMon系统进行了测试,结果表明,该系统能够对运行了主流P2P应用的计算机进行实时识别,并能够统计出对应主机的各类连接数、平均传输速率、P2P应用的服务端口号等信息,以作为局域网网络管理的依据. 相似文献
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鉴于拓扑优化和遗传算法在结构损伤识别中各自的优点,本文将遗传算法、有限元和拓扑优化三种方法相结合,提出了一种用于二维结构多损伤识别的新方法。这种方法将拓扑优化的设计变量和遗传算法的参数统一化,将拓扑优化中的目标函数和约束方程与遗传算法的适应度函数联系起来,并以拓扑优化的约束方程作为控制条件参与整个遗传运算的控制。采用二进制编码遗传算法代替连续变量拓扑优化的方式对发生孔洞损伤形式的二维结构进行损伤识别,避免了利用连续变量拓扑优化进行损伤识别时参数阈值的确定可能给识别结果带来的不良影响。通过对两个二维结构模型的多损伤识别仿真计算,结果显示本方法能够很好地识别二维结构中多个位置的损伤,对于仅用拓扑优化法很难识别的轻微孔洞损伤情况,该方法也能得出与实际情况吻合良好的结果。 相似文献
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Paresh S. Patel David L. Marcum 《International journal for numerical methods in engineering》2008,75(3):355-378
A topology generation algorithm, commonly known as geometry repairing/healing, is presented to detect commonly found geometrical and topological issues like cracks, gaps, overlaps, intersections, T‐connections and no/invalid topology in the model, process them and build correct topological information. The present algorithm is based on the iterative vertex pair contraction and expansion operations called stitching and filling, respectively. The algorithm closes small gaps/overlaps via the stitching operation and fills larger gaps by adding faces through the filling operation to process the model accurately. Moreover, the topology generation algorithm can process manifold as well as non‐manifold models, which makes the procedure more general and flexible. Most of the existing techniques use a constant tolerance for topology generation and suffer from the reliability issues and cannot preserve small details of the same size of gaps/overlaps. This algorithm uses an automatic and adaptive tolerance that enhances reliability of the process and preserves small features in the model. In this way, the combination of generality, accuracy, reliability and efficiency of this algorithm seems to be a significant improvement over existing techniques. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Masood Ahmad Abdul Hameed Fasee Ullah Ishtiaq Wahid Atif Khan M. Irfan Uddin Shafiq Ahmad Ahmed M. El-Sherbeeny 《计算机、材料和连续体(英文)》2021,67(2):1353-1368
Clustering algorithms optimization can minimize topology maintenance overhead in large scale vehicular Ad hoc networks (VANETs) for smart transportation that results from dynamic topology, limited resources and non-centralized architecture. The performance of a clustering algorithm varies with the underlying mobility model to address the topology maintenance overhead issue in VANETs for smart transportation. To design a robust clustering algorithm, careful attention must be paid to components like mobility models and performance objectives. A clustering algorithm may not perform well with every mobility pattern. Therefore, we propose a supervisory protocol (SP) that observes the mobility pattern of vehicles and identifies the realistic Mobility model through microscopic features. An analytical model can be used to determine an efficient clustering algorithm for a specific mobility model (MM). SP selects the best clustering scheme according to the mobility model and guarantees a consistent performance throughout VANET operations. The simulation has performed in three parts that is the central part simulation for setting up the clustering environment, In the second part the clustering algorithms are tested for efficiency in a constrained atmosphere for some time and the third part represents the proposed scheme. The simulation results show that the proposed scheme outperforms clustering algorithms such as honey bee algorithm-based clustering and memetic clustering in terms of cluster count, re-affiliation rate, control overhead and cluster lifetime. 相似文献
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Non-destructive testing (NDT) detects damage according to a difference in a physical phenomenon between a normal structure and damaged structure. As a solution avoiding human errors in NDT, a numerical method based on a dynamical numerical analysis model and a structural optimization algorithm was proposed. This method automatically derives a structure with a response that is equal to that of a damaged structure through an optimization procedure. Among structural optimization methods, topology optimization can optimize the structure fundamentally by changing the topology and not just the shape of a structure. Thus, topology optimization is employed together with eigenfrequency analysis, which is the most fundamental methodology of NDT. The proposed method derives a structure that has the same eigenfrequencies as a damaged structure employing topology optimization. The shape and location of damage can be identified through the optimal shape obtained. 相似文献