Spatial social networks

We introduce a spatial cost topology in the network formation model analyzed by Jackson and Wolinsky, Journal of Economic Theory (1996), 71: 44–74. This cost topology might represent geographical, social, or individual differences. It describes variable costs of establishing social network connections. Participants form links based on a cost-benefit analysis. We examine the pairwise stable networks within this spatial environment. Incentives vary enough to show a rich pattern of emerging behavior. We also investigate the subgame perfect implementation of pairwise stable and efficient networks. We construct a multistage extensive form game that describes the formation of links in our spatial environment. Finally, we identify the conditions under which the subgame perfect Nash equilibria of these network formation games are stable. We are very grateful for the constructive comments of Matt Jackson and an anonymous referee. We also like to thank Vince Crawford, Marco Slikker, Edward Droste, Hans Haller, Dimitrios Diamantaras, and Sudipta Sarangi for comments on previous drafts of this paper.We acknowledge Jay Hogan for his programming support. Part of this research was done while visiting the CentER for Economic Research, Tilburg University, Tilburg, The Netherlands.Financial support from the Netherlands Organization for Scientific Resrarch (NWO), grant B46-390, is gratefully acknowledged.-->,     

Influences on expatriate social networks in China

This study applied social network theory to investigate the factors influencing expatriate social networks and the consequences of expatriate social networks in China. Based on analysis of 171 Taiwanese expatriates in China, this study found that core self-evaluations and extraversion are significant for expatriates in developing expressive and instrumental ties with host country nationals. Moreover, job autonomy assists expatriates in developing instrumental ties with host country nationals. The expressive and instrumental ties of expatriates with host country nationals are significant for overseas adaptation. Finally, instrumental ties with host country nationals are significant for expatriate job performance.     

Research collaboration model in academic social networks

ABSTRACT

This paper proposes a hybrid collaboration recommendation method that accounts for research similarities and the previous research cooperation network. Research cooperation is measured by combining the collaboration time and the number of co-authors who already collaborated with at least one scientist. Research similarity is based on authors’ previous publications and academic events they attended. A weighted directed graph is built to discover new collaborators by using direct and indirect connections between scientists. Moreover, a consensus-based system is built to integrate bibliography data from different sources. The experimental results show that our method improves the recommendation performances over other methods.     

Neighborhood social networks and female self-employment earnings in Taiwan

Using the sample of Taiwanese female self-employed workers from the Taiwan Women and Family Survey (TWFS) conducted in 1989, this article explores neighborhood social networks and female self-employment earnings. The evidence from linear regression and endogenous treatment effect models suggests that an individual’s past provision of personalized assistance to adjacent neighbors significantly increases current self-employment earnings, with corrections for self-selection into network participation. An individual’s past voluntary contributions to community organizational activities also significantly increase current earnings, both with and without corrections for self-selection. However, there are negative self-selections into both cooperative neighborhood networks and community organizational activities in the sense that female self-employed workers with high earnings capacity are less likely to choose to participate in these types of social networks.     

Information lag and dynamic stability

The role of information in economic dynamics is examined. A misconception that the removal of uncertainty always brings additional stability to an existing equilibrium is clarified. It is shown that the relation between information and equilibrium stability is not monotonic. Removing information lag may be either beneficial or detrimental to the stability of an economic equilibrium. Although the focus is on two-dimensional economic system where economically plausible possibilities are studied in theory and numerically illustrated, the conclusions have general implications to any multi-dimensional system.     

Information flows within and across sectors in Chinese stock markets

We examine the patterns of information flows within and across sectors of the two Chinese stock exchanges in Shanghai and Shenzhen during 1994–2001. Using the generalized forecast error variance decomposition, we find a high degree of interdependence, indicating that the sectors are highly integrated and sector prices reflect information from other sectors. Industry is the most influential sector in both exchanges, while Finance in Shenzhen is the least integrated with other sectors. Implications of the findings for investors and policymakers are also discussed.     

A dynamic analysis of collusive networks

This paper investigates the strategic formation of collusive networks in a dynamic framework. A collusive network is a set of market sharing agreements between firms in oligopolistic markets and auctions. Belleflamme and Bloch (Int Econ Rev 45(2):387–411, 2004) fully characterize the pairwise stable collusive networks in their symmetric model. In contrast, we characterize the collusive networks to which a dynamic network formation process converges with positive probability in the symmetric model. We provide a complete characterization for the case of the process that starts from a network with sufficiently few links. Moreover, we show that the process never cycles but always converges to a stable network. In addition, we discuss an asymmetric model where firms enjoy a home country advantage. We show that the expected number of collusive agreements may be reduced by an increase in the degree of the home country advantage. This implies that policies for discouraging entry may fail, and may lead to a decrease in expected social surplus.     

Coordination in the El Farol Bar problem: The role of social preferences and social networks

In this paper, we continue the pursuit of the self-coordination mechanism as studied in the El Farol Bar problem. However, in addition to efficiency (the optimal use of the public facility), we are also interested in the distribution of the public resources among all agents. Hence, we consider variants of the El Farol Bar problem, to be distinguished from many early studies in which efficiency is the only concern. We ask whether self-coordinating solutions can exist in some variants of the El Farol Bar problem so that public resources can be optimally used with neither idle capacity nor congestion being incurred and, in the meantime, the resources can be well distributed among all agents. We consider this ideal situation an El Farol version of a “good society”. This paper shows the existence of a positive answer to this inquiry, but the variants involve two elements, which were largely left out in the conventional literature on the El Farol Bar problem. They are social networks and social preferences. We first show, through cellular automata, that social networks can contribute to the emergence of a “good society”. We then show that the addition of some inequity-averse agents can even guarantee the emergence of the “good society”.     

Identification of peer effects through social networks

We provide new results regarding the identification of peer effects. We consider an extended version of the linear-in-means model where interactions are structured through a social network. We assume that correlated unobservables are either absent, or treated as network fixed effects. We provide easy-to-check necessary and sufficient conditions for identification. We show that endogenous and exogenous effects are generally identified under network interaction, although identification may fail for some particular structures. We use data from the Add Health survey to provide an empirical application of our results on the consumption of recreational services (e.g., participation in artistic, sports and social activities) by secondary school students. Monte Carlo simulations calibrated on this application provide an analysis of the effects of some crucial characteristics of a network (i.e., density, intransitivity) on the estimates of peer effects. Our approach generalizes a number of previous results due to Manski [Manski, C., 1993. Identification of endogenous social effects: The reflection problem. Review of Economic Studies 60 (3), 531–542], Moffitt [Moffitt, R., 2001. Policy interventions low-level equilibria, and social interactions. In: Durlauf, Steven, Young, Peyton (Eds.), Social Dynamics. MIT Press] and Lee [Lee, L.F., 2007. Identification and estimation of econometric models with group interactions, contextual factors and fixed effects. Journal of Econometrics 140 (2), 333–374].     

Machine learning,artificial neural networks and social research

Quality & Quantity - Machine learning (ML), and particularly algorithms based on artificial neural networks (ANNs), constitute a field of research lying at the intersection of different...     

Prior knowledge and social networks in the exploitation of entrepreneurial opportunities

In this study we analyze the effects of prior knowledge and social networks on the exploitation of entrepreneurial opportunities. The prior knowledge considered is associated with the successes and failures experienced in the entrepreneurial trajectory and, therefore, derived from the exploitation of prior opportunities. In analyzing social networks, we examine the strength of the relationships between entrepreneurs, managers and entrepreneurial associations. As an explanatory factor of the entrepreneurial process, we also include the influence of the entrepreneurial opportunities recognized. Through a hierarchical regression analysis, we show that the number of potential opportunities recognized, the number of previous opportunities successfully exploited and the strength of entrepreneurial social networks positively influence the number of opportunities developed and exploited.     

The effect of social distancing on the reach of an epidemic in social networks

How does social distancing affect the reach of an epidemic in social networks? We present Monte Carlo simulation results of a susceptible–infected–removed with social distancing model. The key feature of the model is that individuals are limited in the number of acquaintances that they can interact with, thereby constraining disease transmission to an infectious subnetwork of the original social network. While increased social distancing typically reduces the spread of an infectious disease, the magnitude varies greatly depending on the topology of the network, indicating the need for policies that are network dependent. Our results also reveal the importance of coordinating policies at the ‘global’ level. In particular, the public health benefits from social distancing to a group (e.g. a country) may be completely undone if that group maintains connections with outside groups that are not following suit.

     

信息服务模式及网络利用

当今的用户获取信息的渠道越来越广,这使得信息服务面临着多方面的竞争。对于从事信息服务的工作者而言,如何让信息真正有效地服务于各行各业和广大用户,以及依据什么因素来选择恰当的服务模式与推动模式的更新都是非常重要的。文章初步探讨了信息服务模式的变化,以及网络在信息服务中的利用。     

Exploratory analyses of relief and development operations using social networks

We use social networks to explore how structural factors affect humanitarian organizations’ performance in relief and development operations. Analyses of two recent humanitarian disasters show that having pre-established partnerships among implementers, a central coordinator, high connectivity, and few structural holes facilitates coordination and improves performance. Similarly, cost efficiency analyses of 757 development programs reveal that (i) high performance of donors and beneficiaries is positively related to the amount of implementers they interact with, and (ii) programs connected by common actors are more cost efficient. Finally, short path lengths and frequent connections among actors or programs improve performance in humanitarian operations.     

The role of social networks in shaping entrepreneurial exit strategies

International Entrepreneurship and Management Journal - Extant literature looks at entrepreneurial exit strategies (e.g., stewardship—family succession; financial harvest—sale of the...     

The Naming Game in social networks: community formation and consensus engineering

We study the dynamics of the Naming Game (Baronchelli et al. in J Stat Mech Theory Exp P06014, 2006b) in empirical social networks. This stylized agent-based model captures essential features of agreement dynamics in a network of autonomous agents, corresponding to the development of shared classification schemes in a network of artificial agents or opinion spreading and social dynamics in social networks. Our study focuses on the impact that communities in the underlying social graphs have on the outcome of the agreement process. We find that networks with strong community structure hinder the system from reaching global agreement; the evolution of the Naming Game in these networks maintains clusters of coexisting opinions indefinitely. Further, we investigate agent-based network strategies to facilitate convergence to global consensus.     

Evaluating information diffusion speed and its determinants in social media networks during humanitarian crises

The rapid diffusion of information is critical to combat the extreme levels of uncertainty and complexity that surround disaster relief operations. As a means of gathering and sharing information, humanitarian organizations are becoming increasingly reliant on social media platforms based on the Internet. In this paper, we present a field study that examines how effectively information diffuses through social media networks embedded in these platforms. Using a large dataset from Twitter during Hurricane Sandy, we first applied Information Diffusion Theory to characterize diffusion rates. Then, we empirically examined the impact of key elements on information propagation rates on social media. Our results revealed that internal diffusion through social media networks advances at a significantly higher speed than information in these networks coming from external sources. This finding is important because it suggests that social media networks are effective at passing information along during humanitarian crises that require urgent information diffusion. Our results also indicate that dissemination rates depend on the influence of those who originate the information. Moreover, they suggest that information posted earlier during a disaster exhibits a significantly higher speed of diffusion than information that is introduced later during more eventful stages in the disaster. This is because, over time, participation in the diffusion of information declines as more and more communications compete for attention among users.     

Community connectivity and heterogeneity: clues and insights on cooperation on social networks

While studies on the emergence of cooperation on structured populations abound, only few of them have considered real social networks as the substrate on which individuals interact. As has been shown recently [Lozano et al., PLoS ONE 3(4):e1892, 2008], understanding cooperative behavior on social networks requires knowledge not only of their global (macroscopic) characteristic, but also a deep insight on their community (mesoscopic) structure. In this paper, we look at this problem from the viewpoint of the resilience of cooperation, in particular when there are directed exogenous attacks (insertion of pure defectors) at key locations in the network. We present results of agent-based simulations showing strong evidence that the resilience of social networks is crucially dependent on their community structure, ranging from no resilience to robust cooperative behavior. Our results have important implications for the understanding of how organizations work and can be used as a guide for organization design. This work was supported by Ministerio de Educación y Ciencia (Spain) under grants FIS2006-13321-2 and MOSAICO and by Comunidad de Madrid (Spain) under grant. SIMUMAT-CM. S. Lozano was supported by URV through a FPU grant and by the EU Integrated Project IRRIIS (027568).     

我国区域经济社会发展的动力机制与图景展望

我国区域经济社会发展是以生态支撑力和民生保障力为依托,围绕产业结构调整和转变经济发展方式两大主轴,以投资驱动力、区际联动力、消费拉动力和文化资本力为动力的动态反馈调整系统,呈现出“美丽中国”、幸福中国和特色中国三大图景,以实现十八大报告中提出的到2020年“区域协调发展机制基本形成”的目标。     

Knowledge-sharing rewards in enterprise social networks: effects of learner types and impact of digitisation

ABSTRACT

The era of total digitisation demands companies to seek innovative approaches in managing digital assets. This paper presents and studies an analytical model of an enterprise social network (ESN) employed by organisations in facilitating knowledge sharing and learning. Exploring the design of reward systems that motivate workers to share knowledge, we focus on how the dominant type of learners (avid or impressionable), the network structure of the ESN, and digitisation affect the reward systems. This research provides valuable insights for practitioners to implement appropriate reward systems to promote knowledge sharing and learning in ESNs.