纵向差异下的连接外部性和网络结构分析

在寡头竞争的市场环境里,相互竞争的企业通常会与竞争对手建立连接,从而影响他们在产品市场上竞争的方式。本文我们建立两阶段博弈模型研究企业建立连接的激励以及由此而形成的网络结构形态。在博弈的第一期,具有纵向差异化的企业决定是否与其竞争对手建立连接;企业观察到连接结果后在第二期进行价格竞争。本文的分析显示均衡网络结构与连接效应、连接成本和消费者偏好有关,均衡网络可能仅是一个企业与其它所有企业建立连接的星型网络结构,也可能是没有任何企业建立连接的空网络结构。本文还分析了均衡网络和社会有效网络之间的关系,发现均衡网络和社会有效网络并不总是一致的,从社会计划者的角度看,企业建立连接可能存在激励不足,因此公共政策应该鼓励企业建立连接。     

上下游企业间R&D合作网络形成及其社会福利

研发（Research and Development,R&D）合作网络的形成是企业在创新活动中进行合作的一个重要特征,数据表明,上下游主体间的垂直R&D合作比位于同一市场层面主体间的横向R&D合作网络更普遍。针对企业间R&D合作网络的内生形成问题,首先,建立上游供应商与下游竞争厂商之间同时选择R&D合作链接和R&D投入水平的博弈模型;然后,通过比较所有可能存在的网络结构下各企业的均衡利润水平,识别稳定网络结构并分析R&D投资的效率;接下来,分析稳定网络结构随着横向R&D合作溢出效应和垂直R&D合作溢出效应的演化;最后,通过比较各网络结构下的社会福利,分析稳定网络结构的有效性。结果表明：（1）垂直合作链接促进合作双方的R&D投入,提高合作双方的均衡利润水平;横向合作链接阻碍竞争厂商的R&D投入,随着横向R&D合作溢出效应的增加,厂商R&D投入的竞争效应逐渐高于其成本降低的效应,从而厂商的利润先增加后减小;（2）在适当的溢出效应参数范围内,完全合作网络是唯一的成对稳定网络结构;但是当供应商与其中一个厂商的垂直R&D合作溢出率较高时,稳定网络结构将会发生演化。（3）社会福利分析的结果表明成对稳定网络未必总是最有效的合作网络结构。     

A Structural Model of Dense Network Formation

This paper proposes an empirical model of network formation, combining strategic and random networks features. Payoffs depend on direct links, but also link externalities. Players meet sequentially at random, myopically updating their links. Under mild assumptions, the network formation process is a potential game and converges to an exponential random graph model (ERGM), generating directed dense networks. I provide new identification results for ERGMs in large networks: if link externalities are nonnegative, the ERGM is asymptotically indistinguishable from an Erdős–Rényi model with independent links. We can identify the parameters only when at least one of the externalities is negative and sufficiently large. However, the standard estimation methods for ERGMs can have exponentially slow convergence, even when the model has asymptotically independent links. I thus estimate parameters using a Bayesian MCMC method. When the parameters are identifiable, I show evidence that the estimation algorithm converges in almost quadratic time.     

Altruism in Networks

We provide the first analysis of altruism in networks. Agents are embedded in a fixed network and care about the well‐being of their network neighbors. Depending on incomes, they may provide financial support to their poorer friends. We study the Nash equilibria of the resulting game of transfers. We show that equilibria maximize a concave potential function. We establish existence, uniqueness of equilibrium consumption, and generic uniqueness of equilibrium transfers. We characterize the geometry of the network of transfers and highlight the key role played by transfer intermediaries. We then study comparative statics. A positive income shock to an individual benefits all. For small changes in incomes, agents in a component of the network of transfers act as if they were organized in an income‐pooling community. A decrease in income inequality or expansion of the altruism network may increase consumption inequality.     

Mobilising networks to achieve strategic difference

This article examines the strategies for achieving differentiation through a network approach. The generic strategies models of positioning and the resource-based view have opened up the possibility of strategic difference, but, drawing on a social network approach, this article argues that, rather than accepting strategy as simply market given or internally driven, firms can draw on their unique social networks of relations to make a difference to their strategies. Illustrations from three successful Taiwanese computer firms seeking to secure differentiation of action show that one enjoys a policy-driven network advantage over its domestic rivals, another has developed both technological and familial networks, while the third exploits its established management and production links in the Taiwanese industrial culture. These comparative case studies illustrate that strategies for achieving differentiation can be based on a wide variety of external social networks of relationships (including political, familial, friendship and alumni links, as well as alliances via boards, trade unions and banks etc). The implications for managers are that firms need to expand their external networks of relationships to secure their survival and growth, and should seek to identify and develop structures that are resourceful, rare and inimitable.     

How do actors shape social networks during the process of new product development?

Recent studies on new-idea generation and development have highlighted the role played by network structure in the genesis of new combinations or the process of selecting ideas. However, less attention has been paid to the factors that entice actors to shape social networks during the process of the development of new ideas.This research was conducted in an R&D facility of a semi-conductor company. We analysed the generation of five creative projects and their development over a four-year period. We used a longitudinal approach and collected data through interviews and observations to identify the creative contributions and the actors who were involved at different time periods for each project. We mapped the relationships between actors who contributed to the development of each idea through creative thinking and/or helped it to become accepted both internally and externally over three-year windows. This method generated data on network evolution.We also carried out a qualitative analysis and identified four main factors explaining why actors turn to others during the idea-development process: (1) to gain access to information; (2) to enhance credibility; (3) to exercise one’s influence; and (4) to gain access to knowledge through people or objects. We demonstrate that different types of ties or network structures are relied upon to reap different kinds of benefits. This may partially explain network evolution as an idea progresses through different development stages.     

Risk Pooling Advantages of Manufacturing Network Configuration

The decision of a firm to set up a plant network is influenced by a number of factors, including demand fluctuations across its portfolio of products, logistics costs, and service level requirements. Product plant networks offer the benefits of consolidated production and reduced transshipment costs; on the other hand, process plant networks allow intensive dedication to process expertise and economies of scale. In this paper, we show that, aside from these benefits, process plant networks offer significant risk pooling advantages under a wide range of conditions. We analytically demonstrate that, even without accounting for economies of scale advantages, firms may prefer the process plant network configuration due to the risk pooling benefits offered.     

Which collaborations allow firms to become gatekeepers? A longitudinal analysis of a large-scale collaboration network

Having a gatekeeper position in a collaborative network offers firms great potential to gain competitive advantages. However, it is not well understood what kind of collaborations are associated with such a position. Conceptually grounded in social network theory, this study draws on the resource-based view and the relational factors view to investigate which types of collaboration characterize firms that are in a gatekeeper position, which ultimately could improve firm performance in subsequent periods. The empirical analysis utilizes a unique longitudinal data set to examine dynamic network formation. We used a data crawling approach to reconstruct collaboration networks among the 500 largest companies in Germany over nine years and matched these networks with performance data. The results indicate that firms in gatekeeper positions often engage in medium-intensity collaborations and less likely weak-intensity collaborations. Strong-intensity collaborations are not related to the likelihood of being a gatekeeper. Our study further reveals that a firm's knowledge base is an important moderator and that this knowledge base can increase the benefits of having a gatekeeper position in terms of firm performance.     

Bound and exact methods for assessing link vulnerability in complex networks

Assessing network systems for failures is critical to mitigate the risk and develop proactive responses. In this paper, we investigate devastating consequences of link failures in networks. We propose an exact algorithm and a spectral lower-bound on the minimum number of removed links to incur a significant level of disruption. Our exact solution can identify optimal solutions in both uniform and weighted networks through solving a well-constructed mixed integer program. Also, our spectral lower-bound derives from the Laplacian eigenvalues an estimation on the vulnerability of large networks that are intractable for exact methods. Through experiments on both synthetic and real-world networks, we demonstrate the efficiency of the proposed methods.     

International and National R&D Networks in Unionized Oligopoly

We study the endogenous formation of R&D networks between two domestic and one foreign firms in a unionized oligopoly. We find that the equilibrium networks are sensitive to the extent of knowledge spillovers between networked firms. If spillovers are sufficiently low, the complete network will arise in equilibrium; however, if spillovers are sufficiently high, the foreign partial network that includes a domestic and a foreign firm will arise. Moreover, for intermediate spillovers, no equilibrium network emerges. These results have implications for aggregate outcomes: equilibrium networks are not necessarily optimal in terms of aggregate effective R&D and aggregate firm profits.     

The management of firms’ alliance network positioning: Implications for innovation

In spite of the frequent calls for a much more integrated approach, the field of management still faces the ever continuing challenges in attempting to bridge the gap between academic research and managerial actions and practices. The field of strategic alliances and firms’ networks are those among which research and practice are more diverging. Trying to cover this separation, the article presents an empirical research on automotive industry that investigates the effects on innovation performance of the position that firms occupy in the network of alliances. The hypothesis that guides this research is that innovation is generated not only from the resources that a company is able to develop internally, but also through access to resources and capabilities owned by the external companies and organizations that the firm itself is tied to through alliances and cooperation agreements. Beyond this broad argument, the paper links tightly research and practice showing way and how the quality of access to resources owned by partners is influenced by the position occupied in the network of alliances and not only by the existence of single collaborative ties. Assuming a managerial approach which relies on the milestones of network research, different types of positioning in the network of alliances are discussed and tested on their impact on innovation.     

Strategic Learning and the Topology of Social Networks

We consider a group of strategic agents who must each repeatedly take one of two possible actions. They learn which of the two actions is preferable from initial private signals and by observing the actions of their neighbors in a social network. We show that the question of whether or not the agents learn efficiently depends on the topology of the social network. In particular, we identify a geometric “egalitarianism” condition on the social network that guarantees learning in infinite networks, or learning with high probability in large finite networks, in any equilibrium. We also give examples of nonegalitarian networks with equilibria in which learning fails.     

具有边权特性的社会网络重要成员识别

根据成员间关系的强弱给社会网络中各边赋予权重,将二元网络扩展到边权网络,提出一种新的度量指标。该指标通过累加一个成员在网络中成为关键点的次数来度量其删除后给整个网络带来的损害程度,从而判断该成员对维护网络运行绩效的重要性。通过组织沟通网络的实例分析,说明新指标可以从维护网络安全的视角,有效辨识那些虽然结构位置不显著,但对网络安全具有重大隐患的重要成员。     

A multilevel approach to building and leading learning organizations

A multilevel model is offered proposing that organizational learning is an interdependent system where effective leaders enact intervention strategies at the individual (micro), network (meso), and systems (macro) levels. We suggest that leaders approach organizational learning by setting the conditions and structure for learning to occur, while limiting direct interference in the actual creative processes. First, leaders may increase the level of developmental readiness of individual followers, thereby increasing their motivation and ability to approach learning experiences and adapt their mental models. These individuals then serve as catalysts of learning within and between social networks. Second, leaders may promote the diffusion of knowledge between these knowledge catalysts within and across social networks through influencing both the structure and functioning of knowledge networks. Finally, leaders may target actions at the systems level to improve the diffusion to, and institutionalization of, knowledge to the larger organization.     

An Economic Model of Friendship: Homophily,Minorities, and Segregation

We develop a model of friendship formation that sheds light on segregation patterns observed in social and economic networks. Individuals have types and see type‐dependent benefits from friendships. We examine the properties of a steady‐state equilibrium of a matching process of friendship formation. We use the model to understand three empirical patterns of friendship formation: (i) larger groups tend to form more same‐type ties and fewer other‐type ties than small groups, (ii) larger groups form more ties per capita, and (iii) all groups are biased towards same‐type relative to demographics, with the most extreme bias coming from middle‐sized groups. We show how these empirical observations can be generated by biases in preferences and biases in meetings. We also illustrate some welfare implications of the model.     

考虑社交网络和互联网金融的金融市场超网络均衡研究

社交网络和互联网金融的广泛应用给金融市场发展带来机遇和挑战,金融市场呈现复杂多变、交叉融合的特征,传统的金融市场和监管理论难以适应金融市场发展和风险管理需要。本文从金融网络视角,针对互联网金融发展带来的区别于传统金融的信用风险和操作风险,引入信用惩罚函数和操作风险函数,考虑到加强社交网络关系可提高信息透明度、降低交易成本和交易风险,建立了由资金供给者、互联网金融中介、传统金融中介、资金需求者四种类型金融参与组成的、集成资金流动网络和社交关系网络的金融市场超网络模型,进行金融市场各参与主体的行为分析,建立包括净收益最大化、社交网络关系最大化和风险最小化为目标的多目标决策模型;运用变分不等式将约束条件放松为单边约束,研究包括上述金融市场的均衡条件;最后通过算例的MATLAB仿真验证模型有效性。研究结果表明,考虑与否社交网络关系水平,金融市场的均衡状态不同;社交网络关系水平对互联网金融中介和传统金融中介具有影响作用;为提高市场稳定性和有效性,降低金融风险,互联网金融和传统金融中介需要合作和协同发展。     

股东参与治理的私人收益和社会收益的实证研究

本文探讨了股东参与治理所带来的私人收益、特定股权结构的社会收益以及股权集中成本三者之间的关系。我们分析的结果表明,当股东与经理人员之间的利益冲突水平较高、其它治理机制的作用较弱时,股权集中(股东参与治理的积极性较高)可以创造大量的社会收益;反之,股权的集中与分散程度(股东参与治理的积极性较低)对社会收益的影响不明显。本文的研究结论为我国股东参与治理及股权结构改革提供了重要启示。     

Collaboration spaces in Canadian biotechnology: A search for gatekeepers

The paper studies the network of Canadian biotechnology co-inventors and compares the structure of the links between inventors within, and outside of, the cluster. Two types of proximity between individuals are compared: within cluster co-invention refers to geographical proximity while co-patenting links (network component) represent social proximity between inventors of an epistemic community. We show that the cluster-based subnetworks are more fragmented and less centralized than the network components. The paper then proposes two indicators measuring an inventor's importance as a gatekeeper, i.e. an individual at the cluster's frontier responsible for the inflow of the external knowledge to the cluster.     

Penalizing passenger’s transfer time in computing airlines revenue

Airline strategic alliances result in a form of cooperation where firms can access the resources of others network members in order to create added value for their passengers. The shortcoming of this process is that each member of the network makes individual revenue management decisions to maximize its own income, resulting in a sub-optimal income for the network members.To deal with this problem, this paper suggests a resource allocation based on a transfer pricing mechanism, to cooperatively divide the revenue of a passenger between network members. The method penalizes the total time that a passenger takes for reaching the final destination. The model takes into consideration that the profit is independent of the number of available seats (with a maximum determined for each airline). The method computes the optimal transfer pricing and, at the same time, optimizes the quantity of seats (the booking limits). The solution results in a strong Nash equilibrium, which incorporate both the transfer prices and booking limits. We describe the transfer pricing process using an ergodic, finite and continuous-time Markov game model for multiple players. The revenue of each airline in the supply chain will depend on the number of flight transfers and the transit time of the passenger at the airports: the longer the time to the final destination, the lower the price. We compute a collaborative equilibrium point, useful for understanding the resulting revenue of each member of the network. For solving the game, we employ an iterative method based on a proximal approach that involves time penalization. In our final contribution, we present results from a numerical example, which validates the proposed Markov game model and measures the benefits of the transfer pricing resource allocation.     

Environmental improvement initiatives in the coal mining industry: maximisation of the triple bottom line

Abstract

Mining is an economically important industry, which faces several environmental and social challenges. Other than operational improvement activities, mining companies are increasingly paying attention to reduce greenhouse gas emissions (GHGs) and maximise social welfare to satisfy multiple stakeholders and the rise of corporate social responsible initiatives. Based on a case study analysis of coal mining companies we develop a triple bottom line (TBL) initiatives framework that provides a starting point for mining companies to develop a strategic approach to environmental improvement initiatives that can positively impact all elements of the TBL. We highlight four types of process and offset-based initiatives that are available to mining companies to reduce their GHGs, each having differential effects on elements of the TBL. Our findings suggest the importance of company-wide strategies of looking at initiatives through all rather than individual elements of the TBL. Such a strategy would provide an appropriate estimate of the costs and benefits of the initiatives and results in a balanced approach that takes care of operational improvement, reduces GHGs and improves the social welfare of people engaged in mining operations and wider society.