Online MapReduce processing on two identical parallel machines

In this work we investigate the online over-list MapReduce processing problem on two identical parallel machines, aiming at minimizing the makespan. Jobs are revealed one by one, and each job consists of one map task and one reduce task. The map task can be arbitrarily split and processed on both machines simultaneously, while the reduce task has to be processed on a single machine and it cannot be started unless the map task has been completed. We first show that the general case of the problem reduces to the classical two machine online scheduling model with an optimal competitive ratio of 3/2. For a special case where the map task is at least as long as the reduce task, we prove that no online algorithm can be less than 4/3-competitive. An optimal Greedy algorithm with a matching competitive ratio is proposed as well.     

Deterministic construction of compressed sensing matrices based on semilattices

A central problem in compressed sensing is the construction of sensing matrices. In this paper, we show how to construct sensing matrices by using semilattices, and give many examples of sensing matrices constructed from specific semilattices. Moreover, we show that the new construction for some examples with small parameters gives better sensing matrices compared with previously known constructions.     

Foreign Competition and Innovation: The Mediating Role of Imitation

This study examines the extent to which foreign competition affects the innovation performance of domestic firms through imitation, given firms’ absorptive capacity. In analysing longitudinal firm‐level data from the UK, we find a mediating effect of imitation on the relationship between foreign competition and local firms’ innovation performance, and an inverted U‐shaped relationship between imitation and the innovation performance of local firms. Our findings further reveal that absorptive capacity moderates the mediating effect of imitation, diminishing innovation gains at moderate levels of imitation and mitigating the diminishing innovation performance at high levels of imitation.     

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...     

论美国东欧反导计划对欧洲共同安全与防务政策的影响

美国在东欧部署导弹防御系统的计划,对欧洲安全与防务政策的发展有着诸多深远的影响。对美国导弹防御计划的不同反应,直接造成了欧盟内部的分裂,影响了中东欧新入盟国家的安全与防务选择;该计划刺激俄罗斯对欧洲态度进一步趋向强硬,使欧俄关系出现新的不稳定因素;欧洲在安全与防务领域重新陷入严重依赖美国的境地。东欧反导计划从根本上阻碍了欧盟安全防务一体化的建设。     

Optimal RSUs deployment with delay bound along highways in VANET

In order to broadcast an alert message from the accident site to the control center as soon as possible, the roadside units (RSUs) act as the critical component in vehicular ad hoc networks (VANETs). It is not possible to make a pervasive RSU deployment due to the huge cost and market requirement. Hence, how to deploy a minimum number of RSUs in a given region becomes a challenge problem. In this paper, we present an analysis for the total delay of broadcasting alert messages in VANETs along highways. Based on the analysis, the relationship between optimal number of RSUs with the highway distance is given. Moreover, the experiment results verifies the delay analysis and the optimization of RSUs deployment.     

社交网络个体活跃行为的大数据分析：从网络外部性的视角

用户是社交网络平台的基石,用户的活跃行为为平台创造内容、带来价值,因而用户活跃度一直是社交网络平台的关注重点。已有研究仅关注用户是否存在持续使用意向或行为,将持续使用行为定义为二元变量,未对持续使用行为细分,忽略了对用户活跃行为的研究。此外,社交网络中用户活跃行为之间有着不可忽视的相互影响,而受制于用户的关系网络数据难以获取,少有研究从该角度对社交网络中的用户行为进行研究。 将持续使用行为进一步细分为个体活跃和沉默行为,从网络外部性视角探讨同伴活跃行为对焦点个体活跃行为的影响以及个体网络规模与活跃行为的关系,并进一步探讨个体间关系强度和个体特征的调节作用。以超过百万用户的真实关系网络、个体特征信息和使用行为数据进行实证分析,通过Tobit模型验证上述关系。 研究结果表明,同伴活跃度和个体网络规模对个体活跃度有显著的正向作用,同时关系强度具有正向调节作用;个体特征在同伴活跃度与个体活跃度之间起调节作用,具体来说,女性用户和年轻用户受同伴活跃行为的影响更强。 从网络外部性的角度探讨用户活跃行为的影响因素,拓展了关于在线社交网络用户持续使用行为的研究和网络外部性测量方式,关注不同节点对于网络外部性贡献的差异性,对今后网络外部性的研究有一定的借鉴意义。基于中国数百万真实用户的数据集,结果更具普适性,同时反映出中国在线社交网络中用户的行为特征,可为今后的研究者提供参考。研究结果可以帮助社交网络平台的管理者更加了解用户活跃度的影响机理以及用户行为之间的内在联系,从而能以更科学合理的方式激发用户活跃度,保持社交网络平台的持续运营。     

社会转型时期的民法回归

在传统的民法里,婚姻家庭关系、劳动关系和土地财产关系的调整,均属于民法的任务,但在前苏俄民法里,这些社会关系的调整都脱离民法而呈独立状态。新中国成立后,由于承袭前苏俄的法律观念,也将这些社会关系的调整从民法中剥离出去;改革开放以后,这些社会关系的调整逐渐呈现出不同程度回归民法的趋势。     

《太平经》的词汇研究

《太平经》是研究东汉乃至整个中古汉语的重要语料,但长期以来,围绕这部典籍所展开的语言研究还显得比较薄弱。对《太平经》语言的研究,主要成就集中在文字校勘方面,在词汇、语法方面的成果不多。有关《太平经》词汇研究的成果,主要分布在词语考释,熟语、应叹提顿语等特殊词汇,以及同素异序、同义复词等四个方面。     

法村社会支持网络的整体结构研究块模型及其应用

本文利用“块模型”方法分析黑龙江省一个村落的社会支持网,是针对费孝通教授提出的“差序格局”理论进行社会网络意义上的一种量化研究。研究发现,在“劳力支持”网络和“亲属关系网”中都存在四个子群。这种发现揭示了法村村民之间的互助行为的整体模式。“块模型”的价值在于可以揭示多种社会网络的整体结构和关系模式。因此,块模型方法可用来研究特别重视“关系”的中国社会。