A Weighted Evolving Network with Community Size Preferential Attachment

Community structure is an important characteristic in real complex network. It is a network consists of groups of nodes within which links are dense but among which links are sparse. In this paper, the evolving network include node, link and community growth and we apply the community size preferential attachment and strength preferential attachment to a growing weighted network model and utilize weight assigning mechanism from BBV model. The resulting network reflects the intrinsic community structure with generalized power-law distributions of nodes' degrees and strengths.     

Weighted Evolving Networks with Self-organized Communities

In order to describe the self-organization of communities in the evolution of weighted networks, we propose a new evolving model for weighted community-structured networks with the preferential mechanisms functioned in different levels according to community sizes and node strengths, respectively. Theoretical analyses and numerical simulations show that our model captures power-law distributions of community sizes, node strengths, and link weights, with tunable exponents of v ≥ 1, γ 〉 2, and α 〉 2, respectively, sharing large clustering coefficients and scaling clustering spectra, and covering the range from disassortative networks to assortative networks. Finally, we apply our new model to the scientific co-authorship networks with both their weighted and unweighted datasets to verify its effectiveness.     

基于簇相似度的网络社团结构探测算法

社团结构对复杂系统的结构特性和动力学特性有重要影响.提出了一个度量社团相似度的模型,称为簇相似度.该模型能够度量两个社团的相似度大小,为研究社团间的作用机制提供帮助.而且基于该模型,设计了一个社团划分算法.算法采用层次聚类的思想,每次合并两个相似度最大的社团,并通过一个评价函数选择最优社团划分.数值实验以及与CNM,GN,EigenMod等主流算法做比较,表明本算法的精度和效率都比较高,尤其对于边密度较高的网络,性能非常理想.     

肺心病患者的社区治疗

为探讨社区医疗在治疗重症肺心病中发挥的作用,总结社区治疗经验,对5例重症肺心病患者进行了综合性治疗。结果显示,3例缓解,2例去世,死亡原因中枢呼吸衰竭占首位。讨论了充分利用社区资源,实行家庭、社区的综合性治疗措施。     

Evolution of Cohesion between USA Financial Sector Companies before,during, and Post-Economic Crisis: Complex Networks Approach

Various mathematical frameworks play an essential role in understanding the economic systems and the emergence of crises in them. Understanding the relation between the structure of connections between the system’s constituents and the emergence of a crisis is of great importance. In this paper, we propose a novel method for the inference of economic systems’ structures based on complex networks theory utilizing the time series of prices. Our network is obtained from the correlation matrix between the time series of companies’ prices by imposing a threshold on the values of the correlation coefficients. The optimal value of the threshold is determined by comparing the spectral properties of the threshold network and the correlation matrix. We analyze the community structure of the obtained networks and the relation between communities’ inter and intra-connectivity as indicators of systemic risk. Our results show how an economic system’s behavior is related to its structure and how the crisis is reflected in changes in the structure. We show how regulation and deregulation affect the structure of the system. We demonstrate that our method can identify high systemic risks and measure the impact of the actions taken to increase the system’s stability.     

社区大学数学建模教学及其评估

20世纪以来 ,数学的应用已深入到所有重要学科 ,数学建模也以其广泛的参与性促进了科学技术与经济建设的紧密结合 .我国普通高校数学建模竞赛活动发展迅速 ,而社区大学数学建模教学进展缓慢 .1 996年 ,在三维教学模式研究的基础上 ,丰台职大开设了数学建模新课 ,为北京市社区大学数学建模教学及其评估提供了成功的案例     

Ionic alkylleads in avian tissues from aquatic and terrestrial environments

Ionic alkyllead concentrations in soft tissues of pigeons from urban Montreal and environs were appreciably different from the variety and concentrations of alkyllead analytes which characterized mallard ducks culled from a sanctuary in eastern Ontario. The major toxicant in pigeons, triethyllead (Et₃Pb⁺) reflected the exclusive use of tetraethyllead as a gasoline additive in both regions. Urban colonies of pigeons were characterized by significantly greater concentrations of Et₃Pb⁺ than were specimens from a suburban/rural colony. In contrast, the major toxicant in ducks was trimethyllead although six other alkyllead analytes were also observed. An environmentally mediated methylation of Pb²⁺ which is more active in (but not restricted to) aquatic environments is postulated to account for the ubiquity of trimethyllead in ducks.     

Tracing fourth graders’ learning of fractions: early episodes from a year-long teaching experiment

Considerable and significant research¹ has been conducted focusing on what students know about fraction ideas.² However, much of the research looks at student understanding following some instruction. The research³ reported in this paper differs from other studies in three significant ways: (1) the students were 9- and 10-year-old fourth graders; (2) they had not yet had an introduction to operational rules and definitions about fractions; and (3) the research design emphasized a student-centered approach. The research is based on the view that given particular conditions in which students are invited to work together and conduct thoughtful investigations with appropriate materials, they can build fundamental mathematical ideas.     

DEA方法在城市社区建设绩效评价中的应用

本在运用主成分分析法对评价指标降维的基础上，应用数据包络分析方法对城市社区建设绩效进行了评价，找出了非有效决策单元及今后改进工作的方向，为有关部门提供管理信息和决策依据。     

开源软件社区中人类知识创造行为的个体差异性研究

近年来,利用复杂性科学解释人类行为成为一个新兴的研究热点.与以群体或群体中部分个体为研究对象不同,以codeplex开源软件社区所有个体知识创造行为为研究对象,利用人类行为动力学方法从活跃度、阵发性、时间间隔分布、长程相关性四个侧面对社区中所有个体知识创造过程中的生产行为、沟通行为、bug讨论行为进行分析.发现开源软件社区中生产者个体的这三种行为在活跃度、分布形式及分布参数、阵发性指标、长程相关性都呈现出显著的差异性.最后,对造成这种差异性的原因进行了讨论.