Networks in Conflict: Theory and Evidence From the Great War of Africa

We study from both a theoretical and an empirical perspective how a network of military alliances and enmities affects the intensity of a conflict. The model combines elements from network theory and from the politico‐economic theory of conflict. We obtain a closed‐form characterization of the Nash equilibrium. Using the equilibrium conditions, we perform an empirical analysis using data on the Second Congo War, a conflict that involves many groups in a complex network of informal alliances and rivalries. The estimates of the fighting externalities are then used to infer the extent to which the conflict intensity can be reduced through (i) dismantling specific fighting groups involved in the conflict; (ii) weapon embargoes; (iii) interventions aimed at pacifying animosity among groups. Finally, with the aid of a random utility model, we study how policy shocks can induce a reshaping of the network structure.     

高端装备制造业技术创新资源配置效率及影响因素研究——基于两阶段StoNED和Tobit模型的实证分析

新常态下,高端装备制造业在推动国民经济稳定增长、加快传统工业转型升级、提升产业链核心竞争力的过程中,先导性和战略性作用日益凸出,但其技术创新资源配置的合理性和有效性却成为产业持续发展的主要瓶颈。本文从投入产出角度出发,基于价值链理论,将技术创新活动分为技术研发和技术转化两个阶段,并构建两阶段StoNED模型,采用2011-2014年的行业面板数据作为样本数据,对高端装备制造业技术创新资源配置效率进行测度和比较;以产业组织为视角,利用Tobit模型分析影响效率的关键因素。实证研究表明,我国高端装备制造业技术创新资源配置的整体和阶段效率在子行业间存在不同程度的波动和差异,技术研发阶段效率偏低制约着整体效率的最优化;甄别影响因素发现,企业规模对技术研发阶段效率具有负向作用,对整体和技术转化阶段效率具有正向作用;市场垄断不利于整体和技术转化阶段效率的提升;政府支持对整体和两阶段效率均具有负面影响。在此基础上,进一步提出应对产业技术创新资源配置现状的对策建议。     

Resilience Analysis of Countries under Disasters Based on Multisource Data

Disasters occur almost daily in the world. Because emergencies frequently have no precedent, are highly uncertain, and can be very destructive, improving a country's resilience is an efficient way to reduce risk. In this article, we collected more than 20,000 historical data points from disasters from 207 countries to enable us to calculate the severity of disasters and the danger they pose to countries. In addition, 6 primary indices (disaster, personal attribute, infrastructure, economics, education, and occupation) including 38 secondary influencing factors are considered in analyzing the resilience of countries. Using these data, we obtained the danger, expected number of deaths, and resilience of all 207 countries. We found that a country covering a large area is more likely to have a low resilience score. Through sensitivity analysis of all secondary indices, we found that population density, frequency of disasters, and GDP are the three most critical factors affecting resilience. Based on broad‐spectrum resilience analysis of the different continents, Oceania and South America have the highest resilience, while Asia has the lowest. Over the past 50 years, the resilience of many countries has been improved sharply, especially in developing countries. Based on our results, we analyze the comprehensive resilience and provide some optimal suggestions to efficiently improve resilience.     

Optimal Policies for Perishable Products When Transportation to Export Market Is Disrupted

We consider a problem where a firm produces a variety of fresh products to supply two markets: an export market and a local market. A public transportation service is utilized to deliver the products to the export market, which is cheap, but its schedule is often disrupted severely. Each time this happens, the firm faces the following questions. (i) For a product that has been finished and is waiting for delivery to the export market, should it continue to wait, at an increasing risk of decay, and when should the waiting be terminated and the product be put to the local market? (ii) For a product that has not been finished, should its processing be postponed, so as to reduce the loss from decay after its completion? (iii) What is the best sequence to process the remaining products, according to the information available? We develop, in this study, a model to address these and other related questions. We find optimal policies that minimize the total expected loss in both the make‐to‐order and make‐to‐stock production systems, respectively. For each finished product, we reveal relationships among the desirable waiting time, the price at the local market, and the decaying cost. For unfinished products, we find the optimal start times and processing sequence. Numerical experiments are also conducted to evaluate the optimal policies.     

Packing <Emphasis Type="Bold">[1, Δ]</Emphasis>-factors in graphs of small degree

Given an undirected, connected graph G with maximum degree Δ, we introduce the concept of a [1, Δ]-factor k-packing in G, defined as a set of k edge-disjoint subgraphs of G such that every vertex of G has an incident edge in at least one subgraph. The problem of deciding whether a graph admits a [1,Δ]-factor k-packing is shown to be solvable in linear time for k = 2, but NP-complete for all k≥ 3. For k = 2, the optimisation problem of minimising the total number of edges of the subgraphs of the packing is NP-hard even when restricted to subcubic planar graphs, but can in general be approximated within a factor of by reduction to the Maximum 2-Edge-Colorable Subgraph problem. Finally, we discuss implications of the obtained results for the problem of fault-tolerant guarding of a grid, which provides the main motivation for research.     

Systematisierung der Erfolgsfaktoren von Wissensmanagement auf Basis der bisherigen empirischen Forschung

Zusammenfassung  Der vorliegende Beitrag leitet aus einer umfassenden Bestandsaufnahme der empirischen Forschung zum Wissensmanagement einen Bezugsrahmen der Erfolgsfaktoren ab. Ziel ist die Zuordnung der identifizierten Erfolgsfaktoren zu übergeordneten Aggregationsniveaus (Untersuchungsfelder, Kategorien und Dimensionen) und damit die Reduzierung von Komplexit?t und Systematisierung der bisherigen Befunde. Weiterhin sollen aus den Ergebnissen der vorliegenden Analyse Implikationen für die weitere Forschung im Wissensmanagement abgeleitet werden. Als Ergebnis resultiert ein Modell, welches die Inhalte als auch die hypothetischen Beziehungen zwischen den identifizierten Aggregationsebenen veranschaulicht. Er bildet damit Grundlage für eine weitere Analyse der Erfolgsfaktoren, ihrer Auspr?gungen und Interdependenzen. Aus der Heterogenit?t der Studien konnten weitere Implikationen für die theoretische Wissensmanagement-Forschung abgeleitet werden.

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Knowledge management factors of success: A review of empirical findings and a model for future research

Summary  This paper derives a framework of key success-factors from an in-depth review of empirical research in knowledge management. Our first objective was to reduce the complexity of previous findings in the field of knowledge management by developing a model-structure that focuses on the interdependencies of the identified variables and to develop a framework that would allow for further research. We thus iteratively aggregated the identified factors of success to superior fields of analysis (named research fields, categories and dimensions). Our second objective was to extract from the analysis further implications for future research. The derived hypothetical framework maps the identified levels of aggregation and its describing factors, as well as the hypothetical interdependencies among them. Therefore this framework not only structures the findings, but also provides a basis for further analysis that aims at sound confirmation of the knowledge management factors of success, their characteristics and interdependencies. The observed heterogeneity of existing research points towards further research implications for knowledge management theory.

Forschungsschwerpunkte: Mergers & Acquisitions, Projektmanagement, Wissensmanagement     

研究生职业生涯入口影响因素及其特征差异研究

首先,探究了应届毕业研究生职业生涯入口的影响因素,并按照对研究生就业的作用将影响因素划分为促进因素和阻隔因素;其次,进一步探讨了不同性别、专业学科门类和就职岗位类别等特征的研究生所感知到的阻隔因素和促进因素的差异;最后,从个人,高校和政府3个层面提出了如何克服研究生职业生涯入口阻隔的建议。     

基于随机权重多目标遗传算法的多目标动态单元构建方法

考虑多变的市场需求环境下单元生产系统在多个计划期具有多个目标的动态构建决策问题。通过对单元生产构建过程中的总费用、设备负载与能力之间最大偏差以及零部件跨单元移动的总次数3个目标进行权衡,建立了非线性多目标动态单元构建的数学模型。采用自适应小生境技术、惩罚技术、双轮盘赌法和精华选择策略,提出了基于精华保留策略的随机权重多目标遗传算法求解该组合优化问题。结合实例对模型和算法进行了仿真分析,结果显示了算法对解决多目标动态单元构建问题的有效性。     

内外双向因素与搭便车行为：社会网络的调节作用

研究个人社会网络对个体决策行为的影响能够提高搭便车行为的控制效果.基于损失厌恶理论和羊群效应理论构建分析框架,引入信息公开和信息封闭两种信息条件,研究社会网络对搭便车行为的直接影响和调节作用.通过z-tree软件和调查问卷收集个人信息,运用非参数检验、描述性统计分析等统计方法,对249份样本数据进行实证分析.研究结果表明,两种信息条件下的搭便车行为存在显著差异,在信息公开条件下,社会网络对搭便车行为有直接作用,社会网络不仅对性别、博弈论知识、收入水平、年龄和受教育年限与搭便车行为的关系有显著的调节作用,而且对投资收益率和罚金比率的调节作用也较为显著;在信息封闭条件下,社会网络对搭便车行为的直接作用不显著,且社会网络仅对年龄和收入水平与搭便车行为关系的调节作用显著.将信息结合传统的奖惩机制来控制搭便车行为将更有效.     

中国生产性服务业发展的影响因素研究

明晰和识别中国各地区生产性服务业发展的影响因素,能为不同区域制定合理的产业政策、有效促进区域经济发展提供依据.在理论分析基础上,利用1997年～2006年中国各地区生产性服务业和经济发展的有关数据,利用面板数据模型考察和识别中国转型时期专业化分工、产权结构、效率、工业结构、工业化进程和制造业集聚对东部、中部和西部生产性服务业发展的影响.结果表明,专业化程度加深、效率提高、非国有产权比重的增加与各地区生产性服务业发展显著正相关,而高新技术产业发展对现阶段生产性服务业发展有抑制作用,工业化进程的推进对各地区生产性服务业发展影响微弱;分工深化对东部地区生产性服务业发展的影响最大,而产权结构改变对中部地区影响最大,分工深化和非国有经济比重提高对西部地区生产性服务业发展均有强有力的促进作用.