As noted by theorists such as Blau, Durkheim, Mayhew, and others, interaction opportunity is a fundamental determinant of social structure. One of the most empirically well established factors influencing interaction opportunity is that of physical distance. The strength of this effect in modern societies, however, has been called into question because of technological advances (the so-called d...

In recent years, there has been growing interest in the study of coevolutionary games on networks. Despite much progress, little attention has been paid to spatially embedded networks, where the underlying geographic distance, rather than the graph distance, is an important and relevant aspect of the partner rewiring process. It thus remains largely unclear how individual partner rewiring range...

Location-based social networks (LBSNs) have attracted increasing users in recent years. The availability of geographical and social information of online LBSNs provides an unprecedented opportunity to study the human movement from their socio-spatial behavior, enabling a variety of locationbased services, from mobile marketing to disaster relief. Previous work on LBSNs attempts to utilize a use...

This dissertation is the result of my own work and includes nothing which is the outcome of work done in collaboration except where specifically indicated in the text. This dissertation does not exceed the regulation length of 60 000 words, including tables and footnotes. Summary Online social networking services entice millions of users to spend hours every day interacting with each other. At ...

Studies on friendships in online social networks involving geographic distance have so far relied on the city location provided in users’ profiles. Consequently, most of the research on friendships have provided accuracy at the city level, at best, to designate a user’s location. This study analyzes a Twitter dataset because it provides the exact geographic distance between corresponding users....

We investigate whether the supply of venture capital (VC) is driven by spatial proximity between a VC company and the portfolio firm. Our analysis is based on information about VC investments in Germany between 2004 and 2009. We find that possible problems caused by the geographic distance to a portfolio firm seem to be overcome by syndication of investments with one of the VC firms located clo...

It is a well-established result that the marginal probability of a social tie between two persons declines with geographical distance for a wide range of social relations (see, e.g., Bossard, 1932; Zipf, 1949; Festinger et al., 1950; Hägerstrand, 1967; Freeman et al., 1988; Latané et al., 1995; McPherson et al., 2001). While often regarded as a mere curiosity, others have argued that this relat...

OBJECTIVE In this research, we aim to investigate the necessity of incorporating geographical contacts into Social Network Analysis (SNA) for contact tracing in epidemiology and explore the strengths of multi-mode networks with patients and geographical locations in network visualization for disease spread investigation. BACKGROUND In epidemiology, contact tracing is a process to control the sp...