具有适应度的无标度网络

提出了一个具有适应度的无标度网络模型。每个时间间隔,网络以概率p增加一个新点,并以适应度择优选择m个旧点与新点连接,产生m条新边;以概率1-p按度数择优的规则在旧点之间生成m条新边。对于一些特定的节点适应度的概率密度函数ρ(x)和率函数f(x,y),该网络的度分布具有幂律尾部,且幂律指数2<γ<+∞。     

节点被删除后的复杂网络子集团数量研究

现实当中的许多复杂网络都无法避免地受到来自自然灾害或人为的攻击,从而导致网络破碎成很多大大小小的子集团.计算随机网络和BA无标度网络在随机删除节点与蓄意删除节点两种情况下产生的除最大连通图外其他子集团数量的情况.在产生的子集团中,结果发现它们特点是当节点删除比例f从0增大到1过程中,子集团的数量先增大后减小.包含节点数量较小的子集团数量占子集团总数量的大多数.子集团尺寸与相应数量在尺寸较小时近似成幂律关系.随机与蓄意删除节点时,随机网络与BA无标度网络产生子集团数量的最大值存在差异.     

基于邻节点总度数与随机区分度的无标度网络模型研究

运用复杂网络基础知识,基于BA无标度网络模型构造方法,参考随机初始吸引度网络的优点与不足,提出了一种改进的无标度网络演化模型。该模型以节点区分度代替随机初始吸引度,使旧节点对于新节点的单方面吸引转变为两节点间的相互作用,更突出了不同节点间的差异性;考虑节点的实际影响力,以邻节点总度数作为择优连接标准,避免忽视潜在的重要节点,使网络更符合现实情况。通过实验仿真与分析,验证了该模型服从幂律分布,初始区分度对网络演化具有重要影响,且模型具有更小的邻节点总度数,网络的“贫富悬殊”程度降低,可以模拟更复杂的现实情况。     

单偏好随机网络演化模型

为了进一步探求复杂网络的形成机制,文章提出了一种B A(Barabási-A lbert)模型的扩展模型,考虑网络节点增加的同时,网络内部演化对网络发展的影响.该模型不仅包含加点、加边两种外部演化;而且还包含重连和删边两种内部演化,在每个时间步的操作中,新引入结点的度、重连的边数都是随机的.针对单偏好依附网络模型,运用连续性理论及随机分析理论证明,如果适当选取模型参数,这种网络自演化为无标度网络.而且验证了分析的结果与计算机模拟具有很好的一致性.     

语义网络的结构:我们怎样学习语义知识

分析了2个大型语义网络HowNet和WordNet的全局意义结构.发现两者都是具有小世界和无尺度特征的复杂网络,但具有一些独特的属性.两者连接度分布的幂律指数介于1·0和2·0之间,而不是像许多常见的无尺度网络一样接近于3·0.连接度相关系数都小于0,与生物性网络相似.BA模型以及与其相似的一些模型不能对其动力学加以解释.节点连接度与其聚集度指数之间遵循标度律,表明网络中可能存在自相似的层次结构.认为人类学习语义知识的几种主要方式如聚合与隐喻等影响了语义网络的这些结构特征.     

供给市场均衡变分模型

研究了既包含商品随机选择又包含运输损失的供应链网络均衡模型.研究了商品存在产地、品牌差异（即商品随机选择）和运输损失情况下,具有多种商品流动的三层供应链网络.对生产市场和分销市场,考虑运输损失,建立了基于商品运输损失的优化模型.在上述研究基础上,对具有三个层次的供应链网络,得到了供应链网络各层次的均衡模型和整个供应链网络均衡模型以及与之对应的模型平衡条件、经济解释和变分不等式模型。     

关于教育政策的网络民意的幂律分布研究——以《国家中长期教育改革和发展规划纲要》公开征集意见为政策样本

文章以在教育决策与网络民意对话方面具有里程碑意义的《国家中长期教育改革和发展规划纲要(2010 -2020年)》公开征集意见议题为政策样本,以新浪博客为媒体样本,对关于教育政策的网络民意的幂律分布现象进行研究.研究发现在幂律分布的表象背后,意见领袖与普通博客用户之间存在演变机制——一旦已有的高访问量、高影响力博客不符合意见领袖博客的特征,其他符合特征的博客将取而代之,演变为新的意见领袖.这种演变机制表明,意见领袖的出现具有不可预期性,这使得传统的由政府主导的舆论控制方式不再可行;但与此同时,演变的幂律分布机制有助于提供更丰富的网络民意分布图,从而更好地为科学化民主化决策提供参考.     

注塑成型充填阶段模拟中的黏度模型比较

阐述了常用的热塑性塑料幂律模型、二阶模流模型、Cross模型和Carreau模型等黏性模型表达式和特点。利用仿真的方法得出不同模型下熔体的填充速度、剪切率、剪切应力与温度这4个参数随时间变化曲线,再利用试验的方法采样得到实测值。把仿真值和实验值相对比,得到不同黏性模型的适用场合。结果表明,幂律模型和Carreau模型描述熔体填充速度时比较准确,在填充初始时描述剪切应力和温度变化率时可应用二阶模流模型、Cross模型或Carreau模型,填充后期采用幂律模型更加准确。该结果为合理选取热塑性塑料注射成型CAE填充模拟时材料的黏性模型提供了依据。     

紧密型职教集团若干基本问题研究

紧密型职教集团具有合作关系制度性和规范性较强、合作稳定深入、利益对等共享、集团文化渗透等特征;其组织架构一般包含决策机构、协调机构、执行机构、咨询机构。集团成员"利益共同体"的建设,以合作实体、合作项目等方式进行。     

基于P2P的内容分发网络合作式缓存的研究

在分析基于集中式管理合作缓存系统(CRISP)和基于分布式管理缓存系统(ICPS)的基础上,提出了一种基于P2P的内容分发网络合作式缓存系统模型.该模型具有P2P特点,普通节点既是访问网络的用户节点,又是缓存管理和文件共事的服务节点从而提高了缓存系统的可用性.     

Agricultural information and knowledge network in rural India: a case of Bihar

Purpose: The key informants in a village setup were studied to understand the existing social and knowledge systems of farmers, their structure, and relationships between different actors. The purpose is to identify different channels of information and use them as a means to disseminate agricultural technologies and related information to farmers.

Design: We use the network map analysis in a case study approach as a tool to demonstrate the linkages between the key actors and stakeholders in the information network of farmers.

Findings: The government institutions are well networked among themselves but have limited interactions with non-government sources. Farmers in Bihar have strong linkages with few network actors, who are important nodes in the social knowledge network. The study showed heterogeneity and complexity in the network shape and structure across different districts.

Practical Implications: Knowledge networks and social networks are the drivers of information sharing and play a significant role in the diffusion of agricultural technology and related knowledge. Understanding these networks provides a platform for introducing the agricultural technologies and getting connected to a wider group of farming communities.

Theoretical Implications: The study shows that the network is formed by different actors and their role determine the nature and shape of the network. Knowledge of this heterogeneity is important in designing or revamping agricultural information systems.

Originality: Information and knowledge networks are least explored in the agricultural information dissemination process. Some studies have shown the role of actors and social networks, but this study uniquely explores and presents the heterogeneity of these networks.     

Saving the world through neoliberalism: philanthropic policy networks in the context of Spanish education

This article analyses the processes of ‘neoliberalisation’ in education as directed by Teach For All. Specifically, we explore the case of Empieza por Educar, the Spanish policy network included in Teach For All. The first section seeks to clarify what we understand by the term neoliberalism, using a theoretical dimension through different perspectives. The second section explores the meaning of the new philanthropy. Methodologically, in the third section, the piece of research is categorised under what is defined as ‘Network Ethnography’, an approach which unifies social network analysis with some traditional ethnographic methods. The fourth section explores the meaning Teach For All and its foundation in Spain (Empieza por Educar) as a philanthropic foundation which is changing the political arena. The fifth section explores how Neoliberalism (with big ‘N’) is constructed by means of a complex interconnection of actors and policies that establish the policy network within the Spanish context. The sixth section analyses how neoliberalism (with small ‘n’) is implemented in the curriculum through three aspects: hegemonic truths; the conduct of the conduct (performativity culture); and the modes of formation of the subject with practices of oneself (entrepreneur of oneself).     

A child abuse research network: Now what?

As foundational work in preparation for a sustainable, multi-center network devoted to child abuse medical research, we recently used a combination of survey and modified Delphi methodologies to determine research priorities for future multi-center studies. Avoiding missed diagnoses, and improving selected/indicated prevention were the topics rated most highly in terms of research priority. Several constructive commentaries in this issue identify the key challenges which must be overcome to ensure a successful network. Indeed, as with the clinical work of child abuse pediatrics, a scientific network will also require constant collaboration within and outside the community of child abuse pediatricians, the wider medical community, and even non-medical professions.     

Networks in action: new actors and practices in education policy in Brazil

This paper focuses on the role of networks in the policy-making process in education and discusses the potential of network analysis as an analytical tool for education policy research. Drawing on publically available data from personal or institutional websites, this paper reports the findings from research carried out between 2005 and 2011. Through document analysis, we investigated the composition, activities and strategies adopted by an important policy network in Latin America and traced its developments in Brazil. We adopted the categories – texts, technical artefacts, human beings and money – proposed by Callon to identify the links between the main actors and organizations in that network and drew our conceptual framework from the work of Gramsci in order to analyse the struggle for hegemony and the role of business interests in education policy-making. The findings show that the expansion of networks does not replace the State in education, but rather the State constitutes a strategic node in these networks.     

发挥电大系统优势积极参与并推进社区教育

社区教育是建设学习型社会的主要实现形式之一,参与社区教育是基层电大未来发展的必然选择。电大系统在开展社区教育,推进学习型社会建设过程中具有独特优势。发挥电大优势,构建社区教育网络平台,实现远程教育、社区教育的整合优化,必将有效推进社区教育更好发展。     

提高多层前向神经网络泛化能力的讨论

泛化能力是多层前向神经网络最重要的性能．泛化问题已成为目前神经网络领域的研究热点。本文从泛化理论现有提高神经网络泛化能力的方法等几个方面总结了当前神经网络结构优化与泛化能力研究的现状。神经网络泛化能力的提高可通过神经网络结构的优化和正则化等方法加以实现，并对提高网络泛化能力问题进行讨论。     

代际学习项目如何运行?——行动者网络理论视阈下的个案研究

代际学习正受到越来越多国家的重视。代际学习项目是基于代际学习理论所开展的实践形式,其如何运行,是困扰我国相关研究者与实践者的重要问题。行动者网络理论是一种研究人类与非人类行动者之间相互作用并形成的异质性网络的社会学分析方法,可以通过追随核心行动者的运行脉络,向公众展示以此核心行动者为中心的网络建构过程。基于行动者网络理论的分析框架,对C市的L代际学习项目进行个案分析发现:代际学习项目的运行要素主要包括核心行动者、强制通行点(核心利益诉求)和异质性行动者三类;主要通过核心行动者引领项目的拓展,按强制通行点赋予行动者角色职责,基于利益赋予情况动态招募异质性行动者,积极动员行动者参与网络运行、促进网络可持续发展。从运行效果看,L代际学习项目不仅可以帮助老年学习者获取与时俱进的知识技能,提高身心健康和生活质量,还可以增强老年人的积极认知,使其保持良好生活态度,实现终身学习。我国代际学习项目运行中,一是要注意将核心行动者从单一来源向多来源转变;二是要跳出"学校"边界,凝聚异质的组织行动者;三是要有效利用学习资源,构建合理的强制通行点;四是要实现运行的正规化和互动的非正式化。     

Actor diversity and interactions in the development of banana hybrid varieties in Uganda: implications for technology uptake

Purpose: We examine the nature of networks through which new hybrid banana varieties (HBVs) in Uganda are developed, and how different actors engage in the technology development process.

Design/methodology/approach: We collected the data through 20 key informant interviews and 5 focus group discussions with actors involved in the process. We analysed the data with NVivo and Social Network Analysis software.

Findings: The process of developing HBVs involves many actors with a diversity of roles and interests. The network density was 29.4, implying existence of only 29.4% of the possible direct linkages. Strong ties mainly existed among research-oriented actors, with other actors in the periphery.

Practical implications: The current position of smallholder farmers and other non-research actors inhibits their influence on decisions in the technology development process. We recommend that smallholder farmers should be empowered through better organization so that they can influence the process of developing HBVs. Researchers, supported with appropriate policies, should engage more with actors in the intermediary, enterprise and support service domains for a more vibrant agricultural research system.

Theoretical implications: Application of the systems approach to technology development requires a dynamic process that supports involvement of a diverse range of actors. However, close attention to context is important in dealing with issues of power asymmetries and determining to what extent various actors engage in the process.

Originality/value: This work contributes to literature on systems approaches to agricultural and rural development. The paper demonstrates that actor diversity and interactions are critical in technology development and uptake.     

网络群体性事件的发生机制及其社会效应

作为群体性事件的类型之一,网络群体性事件遵循普遍性的形成机制,网络作为重要变量在机制的各个环节发挥新的作用。网络群体性事件的参与者体现出＂网络最优选择策略＂。通过对参与主体的类型学研究,表明网络群体性事件有两种社会效应：失范倾向与公共性实践。     

美国流行音乐复杂网络建模与分析

复杂网络被应用于各种不同领域的复杂系统分析。以复杂网络为工具,建立一个美国音乐网络,以歌曲、歌手、制作人、曲风及唱片公司为节点,节点之间以相关性为原则连边,从度中心性、中介中心性与特征向量中心性等维度对美国音乐网络进行中心性分析,寻找网络重要节点,并对网络进行社团分割,据此对网络重要社团的规模进行演化分析,发现歌手、制作人重要性与其网络中介中心性有关,歌曲重要性与其网络特征向量中心性有关,美国音乐网络中乡村音乐社团孤立于其它社团,嘻哈音乐流行热度呈上升趋势,正逼近并超过流行音乐热度。分析结果与现实的流行音乐趋势相符,证明用复杂网络对美国音乐流行趋势的建模分析及特征与现象的归纳有效。