基于社会性的DTN网络路由算法研究

针对DTN网络中的消息传输问题,结合概率路由算法PROPHET和社会性路由算法SimBet的基本思想,提出一种DTN网络路由算法——ProSimbet。在选择转发节点时,综合考虑基于历史相遇记录的概率估计和节点的社会性这2个指标,从而降低消息转发次数。实验结果表明,在密集数据集INFOCOM06上,ProSimBet、SimBet、PROPHET和ER这4种路由算法的消息成功转发数目比较接近。在稀疏数据集MIT上,ProSimBet在消息转发次数上比SimBet降低26.1%,在消息成功转发数目上比PROPHET提高7.83%。     

基于社会网络分析方法的南京主城 边缘带绿色空间景观系统评估

中国国土空间发展正经历着一系列变革。城市边缘区的绿色空间体系作为城市与乡村之间过渡地带的自然资源要素,不仅承担着区域居民日常休闲的功能,还具有连续城乡生态系统、调控环境韧性能力等多重功能。以南京主城边缘带绿色空间景观系统为例,运用社会网络分析方法对南京绿色空间系统进行评估。系统评价从个体、局部和整体3个空间尺度展开。个体对每个景观斑块的中心性进行计算得到整个系统的核心要素,局部考察景观系统的层级结构,整体则从系统完备性和结构稳定性出发进行综合评估。通过对系统3个不同空间尺度的分析与评估,探索城市边缘区绿色空间健康发展的有效途径。     

Identification of influential vertices in complex networks: A hitting time-based approach

Unravelling the dynamics of network vertices is pivotal, and traditional centrality measures have limitations in adapting to structural changes, directed and weighted networks, and temporal analyses. This paper introduces a ground breaking approach - hitting time-based centrality. Utilizing network matrix notations and a random walk model on a connected network , we establish a Markov chain to quantify the hitting time, hitting distance, and hitting centrality, providing a nuanced measure prioritizing central vertices. Through extensive experiments using Kendall's tau coefficient, the paper evaluates the method's correlation with actual influence in the Susceptible-Infectious (SI) model, showcasing superior performance across diverse network sizes and structures. The hitting centrality method exhibits sensitivity to connectivity dynamics, effective incorporation of temporal dynamics, and robust handling of weighted and directed networks. Positive Kendall's tau coefficients underline the method's proficiency in prioritizing influential vertices by correlating hitting centrality values with actual infection ability. The demonstrated robustness to structural changes enhances its utility for dynamic network analysis. In conclusion, our hitting time-based centrality approach emerges as a promising method, mitigating the shortcomings of traditional measures. By integrating information propagation speed, accommodating network dynamics, and enabling time-dependent analyses, it offers a comprehensive tool for evaluating vertex importance and influence in complex networks.     

基于重叠盒覆盖算法的节点重要度评估

由于单一的节点评估方法存在不足,在融合复杂网络的局部特征以及全局特征前提下,提出了一种基于重叠盒覆盖算法的节点重要度评估方法.该方法利用重叠中心性对网络中的节点进行重要度排序,并且与其他不同中心性方法在复杂网络数据集中的节点排序方法进行比较;利用susceptible-infected (SI)模型模拟不同中心性方法前10个节点的传播能力,在此基础上以肯德尔系数进行比较,肯德尔系数越大表明相关性越高.实验结果表明,与其他中心性方法相比,重叠中心性得到的初始节点集合的累积平均感染能力高于其他中心性方法,并且与SI模型具有较高的相关性,该方法对于节点重要度评估是有效并且可行的.     

A site entropy rate and degree centrality based algorithm for image co-segmentation

In this paper, we propose a graph based algorithm that efficiently segments common objects from multiple images. We first generate a number of object proposals from each image. Then, an undirected graph is constructed based on proposal similarities and co-saliency maps. Two different methods are followed to extract the proposals containing common objects. They are: (1) degree centrality of nodes obtained after graph thresholding and (2) site entropy rate of nodes calculated on the stationary distribution of Markov chain constructed on the graph. Finally, we obtain the co-segmented image region by selecting the more salient of the object proposals obtained by the two methods, for each image. Multiple instances of the common object are also segmented efficiently. The proposed method has been compared with many existing co-segmentation methods on three standard co-segmentation datasets. Experimental results show its effectiveness in co-segmentation, with larger IoU values as compared to other co-segmentation methods.     

Finding influential agent groups in complex multiagent software systems based on citation network analyses

Current complex engineering software systems are often composed of many components and can be built based on a multiagent approach, resulting in what are called complex multiagent software systems. In a complex multiagent software system, various software agents may cite the operation results of others, and the citation relationships among agents form a citation network; therefore, the importance of a software agent in a system can be described by the citations from other software agents. Moreover, the software agents in a system are often divided into various groups, and each group contains the agents undergoing similar tasks or having related functions; thus, it is necessary to find the influential agent group (not only the influential individual agent) that can influence the system outcome utilities more than the others. To solve such a problem, this paper presents a new model for finding influential agent groups based on group centrality analyses in citation networks. In the presented model, a concept of extended group centrality is presented to evaluate the impact of an agent group, which is collectively determined by both direct and indirect citations from other agents outside the group. Moreover, the presented model addresses two typical types of agent groups: one is the adjacent group where agents of a group are adjacent in the citation network, and the other is the scattering group where agents of a group are distributed separately in the citation network. Finally, we present case studies and simulation experiments to prove the effectiveness of the presented model.     

输电网网架恢复方案关键线路辨识

大停电后根据输电网网架恢复预案进行重构操作的过程中,如果预案中某些关键线路由于外界环境和自身存在的薄弱环节投运失败,将严重影响系统恢复进程.文中结合大停电后输电网网架恢复过程中线路投运失败的情况,借鉴复杂网络理论中介数的概念,定义了一种相对线路介数指标,并在此基础上提出了网架恢复方案中的线路关键度指标作为辨识方案中关键...     

The development of preschool children's (Homo sapiens) uses of objects and their role in peer group centrality.

The ways in which objects were used by preschool children (Homo sapiens) was examined by directly observing them across one school year. In the first objective we documented the relative occurrence of different forms of object use and their developmental growth curves. Second, we examined the role of different types of object use, as well as novel and varied uses of objects, in predicting peer group centrality. Results indicated that noninstrumental object play was the most frequently observed category, followed by tool use, exploration, and construction; sex moderated the growth curve of children's exploration. Noninstrumental object play, not other types of object use, was significantly related to novel and varied object uses and only the latter category predicted peer group centrality. Results are discussed in terms of the social transmission of novel object use. (PsycINFO Database Record (c) 2011 APA, all rights reserved)