Reliable Ad Hoc Routing Based on Mobility Prediction

Reliability is a very important issue in Mobile Ad hoc NETworks (MANETs). Shortest paths are usually used to route packets in MANETs. However, a shortest path may fail quickly, because some of the wireless links along a shortest path may be broken shortly after the path is established due to mobility of mobile nodes. Rediscovering routes may result in substantial data loss and message exchange overhead. In this paper, we study reliable ad hoc routing in the urban environment. Specifically, we formulate and study two optimization problems. In the minimum Cost Duration-bounded Path (CDP) routing problem, we seek a minimum cost source to destination path with duration no less than a given threshold. In the maximum Duration Cost-bounded Path (DCP) routing problem, we seek a maximum duration source to destination path with cost no greater than a given threshold. We use a waypoint graph to model the working area of a MANET and present an offline algorithm to compute a duration prediction table for the given waypoint graph. An entry in the duration prediction table contains the guaranteed worst-case duration of the corresponding wireless link. We then present an efficient algorithm which computes a minimum cost duration-bounded path, using the information provided in the duration prediction table. We also present a heuristic algorithm for the DCP routing problem. In addition, we show that the proposed prediction and routing schemes can be easily applied for designing reliable ad hoc routing protocols. Simulation results show that our mobility prediction based routing algorithms lead to higher network throughput and longer average path duration, compared with the shortest path routing. This research was supported in part by ARO grant W911NF-04-1-0385 and NSF grant CCF-0431167. The information reported here does not reflect the position or the policy of the federal government.     

适应性预期、复杂网络与标准扩散动力学——基于计算经济学的研究

标准扩散是现代产业经济中的重要问题.主要采用复杂网络的小世界网络模型和基于agent的计算机建模技术,结合行为博弈学习理论中的EWA算法,对网络外部性下标准扩散过程中的适应性预期进行研究.基于个体在局部网络中的交互作用和个体行为的学习演化与预期自适应调整,通过计算机仿真就适应性预期对标准扩散的影响从多方面进行分析.研究结果揭示了个体适应性预期在标准扩散中的重要作用,发现扩散中的"涌现"现象,个体邻域结构的随机性对标准扩散结果及其最终分布状态有很大的影响,个体预期能够逆转标准扩散中的先发优势,预期速度调整因子在不同预期强度下有完全不同的影响,个体对新标准的较高预期也是新标准得以扩散的必要条件.     

A note on special optimal batching structures to minimize total weighted completion time

A batch is a subset of jobs which must be processed jointly in either serial or parallel form. The algorithmic aspects of the batching scheduling problems have been extensively studied in the literature. This paper presents necessary and sufficient conditions of the existence of optimal batch sequences for the single machine, batching, total weighted completion time scheduling problems on two batching ways: (1) all jobs form one batch; (2) each batch contains a single job. This kind of conditions can help us to recognize some special optimal schedules quickly. Research supported by NSFC (10671183).     

基于道路扩容的道路拥挤定价收入再分配研究

道路拥挤已经成为世界各国面临的一个普遍难题,道路扩容和道路拥挤定价是缓解交通拥挤的有效手段.本文在分析道路拥挤定价收入用于道路扩容后对交通出行者效用的影响的基础上,构建了基于道路扩容的道路拥挤定价收入再分配双层规划模型,并给出求解算法和实证分析.     

项目风险识别量化方法研究

在构建了项目风险管理系统的基础上,结合系统辨识理论,建立了风险管理系统的输入输出模型,从理论上给出管理偏差与项目风险之间的数学关系;从而,提高了风险识别的准确度、可信度,而且简便易行,为项目风险系统的管理策略制定提供理论基础和依据.最后,通过实例计算说明了基于系统辨识理论的项目风险识别模型的可行性和有效性.     

知识型团队动态能力构建、团队体系模型与创新运作模式研究

知识型团队是现代组织执行复杂创新任务的重要组织形式.本文从分析知识型团队与知识工作任务的匹配关系入手,在引入知识链及知识链网络等概念的基础上,探讨了基于知识链的知识型团队的动态能力构建机制,分析了围绕知识链网络的知识团队结构体系模型及创新运作机理.     

Developing virtual team performance: an integrated perspective of social exchange and social cognitive theories

Review of Managerial Science - The emerging trend toward physically distributed work teams has necessitated a critical inquiry into the nature and roles of psychological contract and leadership in...     

Multiple L(j,1)-labeling of the triangular lattice

Let n,j,k be nonnegative integers. An n-fold L(j,k)-labeling of a graph G is an assignment f of sets of nonnegative integers of order n to the vertices of G such that, for any two vertices u,v and any two integers a∈f(u), b∈f(v), |a?b|≥j if uv∈E(G), and |a?b|≥k if u and v are distance two apart. The span of f is the absolute difference between the maximum and minimum integers used by f. The n-fold L(j,k)-labeling number of G is the minimum span over all n-fold L(j,k)-labelings of G. Let n,j,k and m be nonnegative integers. An n-fold circular m-L(j,k)-labeling of a graph G is an assignment f of subsets of {0,1,…,m?1} of order n to the vertices of G such that, for any two vertices u,v and any two integers a∈f(u), b∈f(v), min{|a?b|,m?|a?b|}≥j if uv∈E(G), and min{|a?b|,m?|a?b|}≥k if u and v are distance two apart. The minimum m such that G has an n-fold circular m-L(j,k)-labeling is called the n-fold circular L(j,k)-labeling number of G. This paper provides upper and lower bounds for the n-fold L(j,1)-labeling number and the n-fold circular L(j,1)-labeling number of the triangular lattice and determines the n-fold L(2,1)-labeling number and n-fold circular L(2,1)-labeling number of the triangular lattice for n≥3.     

网络治理研究前沿与述评

"网络治理"是一个跨学科的研究领域,是技术网络、组织网络和社会网络研究的热点问题,企业网络治理也是工商管理领域的前沿研究方向。技术网络治理、社会网络治理、组织网络治理以及三者的融合是当前组织理论和战略管理理论研究的核心命题,也是中国经济转型过程中转换企业发展模式、实现后发优势的重要课题。本文首先对技术网络治理、社会网络治理和组织网络治理近年来国内外相关研究进行回顾;进而从网络组织与网络治理的内涵、公司治理到网络治理的发展、研究内容及科学问题以及研究动因和研究方法等视角对已有研究文献进行述评;在此基础上,提出了可供研究者参考的未来研究方向。