Splitting trees at vertices

We present tight bounds on splitting trees into “small” subtrees.     

移动互联技术助力博物馆社会化服务

移动互联网技术和智能手机发展给博物馆带来了新的契机,同时也给观众带来了新颖独特的体验,利用移动互联网延伸博物馆的社会教育服务功能,科技与文化相结合,将文化送到公众手上,科技助力文化传播可以让文化更亲民,让文化服务更惠民。借助移动互联网技术,利用3G/4G手机、PAD等各类移动终端,运用最新的掌上微游、数字导览、知识图谱、社交互动等方式打造可以随身携带的博物馆。     

企业关系视角下的知识流程外包策略研究

基于企业的关系视角,讨论了企业选择知识流程外包的可能动机。具体而言,在控制服务成本差的背景下,考虑企业间协同合作产生的关系租金与知识传递的信息粘性对企业选择外包策略进行分析。区别于传统基于服务成本差的外包策略,结论指出由于存在信息粘性的影响,服务提供商仅仅具有较高信息处理能力是不能保证企业选择外包。同时指出,即使当服务提供商不具有任何成本优势,基于合作战略的高关系租金也能成为企业选择知识流程外包的又一动机。通过将成本优势和关系优势进行比较,我们指出两类优势对于企业的外包绩效具有互补性,对于企业进行知识流程外包的决策具有替代性。     

一种基于MapReduce的知识聚类与统计机制

网络文献知识库中的海量资源及其分类的粗粒度,导致学习者容易在文献检索和阅读过程出现认知迷航和知识过载问题。该文提出一种基于MapReduce的知识聚类与统计机制：首先,提出基于MapReduce的共现矩阵构建算法MR-CoMatrix;其次,将共现矩阵与相似度系数结合构建相似度矩阵;然后,通过Z Scores对相似度矩阵进行标准化;最后,使用离差平方和法(Ward,s method)对相似度矩阵进行聚类,生成树状的知识聚类谱系图;基于聚类结果,提出基于MapReduce的知识文献统计算法MR-Statistics,对每个分类的知识属性进行统计。实验结果表明：将MR-CoMatrix和MR-Statistics方法应用于网络文献知识库进行知识聚类和统计,达到较理想的聚类精度和计算效率,实现了细粒度知识聚类和多维统计,同时减少了时间开销。     

基于最小生成树的异构传感器网络抗共谋优化方案

基于EBS (Exclusion Basis Systems)的密钥管理协议,以安全性高、动态性和扩展性好,较适用于异构传感器网络,但却存在共谋问题。该文提出了一种基于MST (Minimum Spanning Tree)的密钥共谋问题优化方案。该方案利用Prim算法对由簇内感知节点所构成的无向连通图进行最小生成树求解,并对该树进行遍历,根据所得节点遍历顺序进行密钥的指派与分配,使得相邻节点间所含的密钥重叠程度增大,发生共谋的可能性得到降低。实验结果表明：同比于密钥随机分配方案与SHELL方案,所提方案有效提高了网络的抗捕获能力。     

基于搜索规则和交叉熵优化的无人机路径规划方法

针对快速扩展随机树(RRP)算法计算效率低、不具备渐进最优性等问题,该文提出一种基于搜索规则和交叉熵优化的改进RRT(IRRT)算法。在路径搜索过程中根据当前节点位置及搜索规则,调整搜索步长及搜索方向,实现高效、快速的初始路径规划。然后,利用交叉熵理论优化初始路径,使得路径具备渐进最优性。仿真实验1结果表明所提方法的有效性和收敛性,仿真实验2将该文所提算法与多种变体RRT算法进行比较,结果表明所提算法能够保证计算效率,同时使得路径具备渐进最优性。     

Weighted allocation rules for standard fixed tree games

In this paper we consider standard fixed tree games, for which each vertex unequal to the root is inhabited by exactly one player. We present two weighted allocation rules, the weighted down-home allocation and the weighted neighbour-home allocation, both inspired by the painting story in Maschler et al. (1995) . We show, in a constructive way, that the core equals both the set of weighted down-home allocations and the set of weighted neighbour allocations. Since every weighted down-home allocation specifies a weighted Shapley value (Kalai and Samet (1988)) in a natural way, and vice versa, our results provide an alternative proof of the fact that the core of a standard fixed tree game equals the set of weighted Shapley values. The class of weighted neighbour allocations is a generalization of the nucleolus, in the sense that the latter is in this class as the special member where players have all equal weights.     

Mach-Zehnder interferometer-based tree architecture for all-optical logic and arithmetic operations

Interferometric devices for optical processing have been of great interest in recent years. Semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI) has already taken a significant role in the field of ultra-fast all-optical signal processing. Optical tree architecture (OTA) provides important contributions in optical interconnecting networks. In this communication, we have tried to exploit the advantages of both OTA and SOA-based MZI switches. We have proposed SOA-MZI-based tree architecture, a new and alternative scheme, for integrated all-optical logic and arithmetic operations. This architecture can enable one to perform all-optical processing of signals, including two input logic operations, half-adder, full-adder, full-subtractor, one-bit data comparator, etc.