<p>The problem of social diffusion has animated sociological thinking on topics ranging from the spread of an idea, an innovation or a disease, to the foundations of collective behavior and political polarization. While network diffusion has been a productive metaphor, the reality of diffusion processes is often muddier. Ideas and innovations diffuse differently from diseases, but, with a few exceptions, the diffusion of ideas and innovations has been modeled under the same assumptions as the diffusion of disease. In this dissertation, I develop two new diffusion models for "socially meaningful" contagions that address two of the most significant problems with current diffusion models: (1) that contagions can only spread along observed ties, and (2) that contagions do not change as they spread between people. I augment insights from these statistical and simulation models with an analysis of an empirical case of diffusion - the use of enterprise collaboration software in a large technology company. I focus the empirical study on when people abandon innovations, a crucial, and understudied aspect of the diffusion of innovations. Using timestamped posts, I analyze when people abandon software to a high degree of detail. </p><p>To address the first problem, I suggest a latent space diffusion model. Rather than treating ties as stable conduits for information, the latent space diffusion model treats ties as random draws from an underlying social space, and simulates diffusion over the social space. Theoretically, the social space model integrates both actor ties and attributes simultaneously in a single social plane, while incorporating schemas into diffusion processes gives an explicit form to the reciprocal influences that cognition and social environment have on each other. Practically, the latent space diffusion model produces statistically consistent diffusion estimates where using the network alone does not, and the diffusion with schemas model shows that introducing some cognitive processing into diffusion processes changes the rate and ultimate distribution of the spreading information. To address the second problem, I suggest a diffusion model with schemas. Rather than treating information as though it is spread without changes, the schema diffusion model allows people to modify information they receive to fit an underlying mental model of the information before they pass the information to others. Combining the latent space models with a schema notion for actors improves our models for social diffusion both theoretically and practically. </p><p>The empirical case study focuses on how the changing value of an innovation, introduced by the innovations' network externalities, influences when people abandon the innovation. In it, I find that people are least likely to abandon an innovation when other people in their neighborhood currently use the software as well. The effect is particularly pronounced for supervisors' current use and number of supervisory team members who currently use the software. This case study not only points to an important process in the diffusion of innovation, but also suggests a new approach -- computerized collaboration systems -- to collecting and analyzing data on organizational processes.</p> / Dissertation

The domination of Etruria by Rome is an aspect of Roman colonization which is generally well understood. Etruria, which began as a significantly more powerful entity than Rome, was brought to heel through the establishment of bilateral treaties and Roman colonies. This study seeks an even further nuanced model for the nature of the conquest of Etruria-namely looking at the underlying mechanisms that made the treaties and colonies successful. Social network analysis is particularly well suited for this task as it visualizes interaction and exchange between sites which often times dictates a sites success or failure. When enlarged to the regional scale SNA can be used to understand how a region prospers or declines based on site interactions. For my study I used SNA to discuss how Roman conquest affected Etruscan exchange networks-especially economic exchange networks-and how this network transformation was used to control the region of Etruria. The results show that Rome all but replaced the previous Etruscan network with their own Imperial network that seems, based on preliminary research, centered on strategically selected administration centers in Etruria-utilizing both native Etruscan sites and newly inaugurated Roman colonies.

No description available.

This thesis consists of three independent and self-contained chapters regarding information and networks. The abstract of each chapter is given below. CHAPTER 1: The seminal “agreeing to disagree” result of Aumann (1976) was generalized from a probabilistic setting to general decision functions over partitional information structures by Bacharach (1985). This was done by isolating the relevant properties of conditional probabilities that drive the original result – namely, the “Sure-Thing Principle” and “like-mindedness” – and imposing them as conditions on the decision functions of agents. Moses & Nachum (1990) identified conceptual flaws in the framework of Bacharach (1985), showing that his conditions require agents’ decision functions to be defined over events that are informationally meaningless for the agents. In this paper, we prove a new agreement theorem in information structures that contain “counterfactual” states, and where decision functions are defined, inter-alia, over the beliefs that agents hold at such states. We show that in this new framework, decisions are defined only over information that is meaningful for the agents. Furthermore, the version of the Sure-Thing Principle presented here, which accounts for beliefs at counterfactual states, sits well with the intuition of the original version proposed by Savage (1972). The paper also includes an additional self-contained appendix in which our framework is re-expressed syntactically, which allows us to provide further insights. CHAPTER 2: We develop a parsimonious and tractable dynamic social network formation model in which agents interact in overlapping social groups. The model allows us to analyze network properties and homophily patterns simultaneously. We derive closed-form analytical expressions for the distributions of degree and, importantly, of homophily indices, using mean-field approximations. We test the comparative static predictions of our model using a large dataset from Facebook covering student friendship networks in ten American colleges in 2005, and we calibrate the analytical solutions to these networks. We find good empirical support for our predictions. Furthermore, at the best-fitting parameters values, the homophily patterns, degree distribution, and individual clustering coefficients resulting from the simulations of our model fit well with the data. Our best-fitting parameter values indicate how American college students allocate their time across various activities when socializing. CHAPTER 3: We examine three models on graphs – an information transmission mechanism, a process of friendship formation, and a model of puzzle solving – in which the evolution of the process is conditioned on the multiple edge types of the graph. For example, in the model of information transmission, a node considers information to be reliable, and therefore transmits it to its neighbors, if and only if the same message was received on two distinct communication channels. For each model, we algorithmically characterize the set of all graphs that “solve” the model (in which, in finite time, all the nodes receive the message reliably, all potentially close friendships are realized, and the puzzle is completely solved). Furthermore, we establish results relating those sets of graphs to each other.

Typically, ephemeral aspects of material culture, such as gestures and sound, are often overlooked in the reconstruction of culture history which is unfortunate since sound-related artefacts offer clues to our understanding of practices and interactions between groups of individuals. With a music archaeological perspective, my research discusses aerophones recovered from the G-752Rj site in the southern portion of the Greater Nicoya archaeological region associated with pre-Columbian Tempisque (500 B.C. to A.D. 300) communities. I examine variation and/or consistency within the production, consumption, and deposition of these instruments to investigate intra-site micro-scale levels of community of practice. I propose an innovative approach at identifying communities of practice by analyzing sound and gestures within an instrument’s construction. / Graduate / 2017-08-08 / 0324 / 0336 / 0986 / katrina.kosyk@mail.mcgill.ca

L’e-réputation corporate constitue une des clés du succès et de la pérennité des entreprises ; elle est difficilement maîtrisable et son management est complexe. L’influence des messages traditionnels corporate (signaux directs émis par l’entreprise) est amoindrie au profit des médias gagnés qui ne cessent de prendre de l’ampleur. Les praticiens et les chercheurs s’interrogent sur les leviers d’action alternatifs. La voix digitale des employés, principalement sur les réseaux sociaux professionnels, semble être une ressource sous-estimée par les entreprises. Cette recherche vise à répondre au questionnement général suivant : l’entreprise peut-elle gérer la construction de son e-réputation corporate afin d’en influencer sa perception en utilisant la voix de ses employés via l’e-contenu de leur « Profil » sur les réseaux sociaux professionnels ? Deux études quantitatives analysent l’usage effectif de l’e-contenu des Pages Entreprises LinkedIn (PEL) et des Pages Personnelles LinkedIn (PPL) ainsi que la perception de la qualité et de la notoriété des PEL et des PPL. Une troisième étude teste l’influence des index d’informations et de visibilité des PEL ainsi que des index de citation et de participation des PPL sur l’e-réputation corporate perçue des PEL et des PPL. L’effet modérateur de la crédibilité perçue des PEL et des PPL est aussi testé. Les résultats – issus de l’analyse de 10 PEL, 1 000 PPL et 1 500 individus – confirment le rôle majeur de la voix digitale des employés dans la construction de l’e-réputation corporate. / Corporate e-reputation is one of the main key’s to a company’s success and durability; it is not easy to control and its management is complex. The influence of corporate traditional messages (direct signals produced by companies) has reduced in favor of earned medias that never stop spreading. Both professionals and academics wonder about alternative solutions.The digital voice of employees, mainly on professional social networks, seems to be an interesting resource companies still underestimate. This research aims to answer the following general question: can a company build its corporate e-reputation, in order to influence perception, using the voice of its employees through the e-content of their “Profile” on professional social networks? Two quantitative studies (I have conducted) analyze the effective use of LinkedIn Business Pages’ (LBP) and LinkedIn Personal Pages’ (LPP) content as well as the perception of LBP’s and LPP’s quality and renown. A third study tests the influence of LBP’s information and visibility index as well as LPP’s quotation and participation index on LBP’s and LPP’s perceived corporate e-reputation. The moderator role of LBP’s and LPP’s perceived credibility is also discussed. Results – following from the analysis of 10 LBP, 1 000 LPP and 1 500 subjects – confirm the essential role of employees’ digital voice with regard to corporate e-reputation building.

Migrant social networks have become somewhat of a trademark of global migration. Social networks and their development cannot only be recognized as a by product of migration, instead what has been noted is that social networks have emerged as primary actors in the migration process as seen in the incidence of the Asian migrant population in Lenasia. The use of social networks by migrants allow for migrants to accrue a range of benefits such as access to accommodation, employment, security and participation in social activities. With regard to the research report, the use of social networks by Asian migrants to access accommodation in Lenasia has been the focus of the study. Initial assumptions about this transient community entailed that migrants in Lenasia were generally unable to access accommodation through other formalised mechanisms such as rental companies therefore they relied on social networks. This has however been proven incorrect and what was found was that the migrant population had in fact never considered or utilised the services of a rental company because their social networks had always successfully met their accommodation needs. The occurrence of migrant social networks in Lenasia has initiated further migration into the area, and subsequently led to the development of migrant enclaves operating in isolation from the pre-existing community. The effect the creation of migrant enclaves in Lenasia has had on the area’s development trajectory is explored in the research. In addition the consequences of migrant enclaves and separate social networks between the pre-existing and migrant community are investigated

Thesis advisor: Michael Malec / This essay is based upon the results of an exploratory research project that explores the ways in which twenty-four (24) individuals, who self-identify as African Americans, define community and use those definitions to inform their perceptions and discussions about civic engagement, responsibility, and community memberships, key themes in the decline of community cultural critique. The research focuses on these themes because they are at the heart of the decline of civil society – individuals are becoming atomistic, alienated, and disengaged from social and interpersonal relationships with family members, neighbors and friends. This psychological and physical distancing leads to a lack of participation in community life and institutions and the loss of social and cultural capital. The structural-functionalist and systemic analyses, upon which much of the decline of civil society social commentary is based, incorrectly assume a linear continuum of human and societal development. When in fact social, political, and economic development actually occur at different stages and at times simultaneously. There is a false dichotomy between the macrolevel theories of urban-rural, folk-peasant, organic-mechanical, and instrumental-expressive models often used to explain and, or predict the nature of conditions under which social relationships and institutional dynamics occur. These macrolevel theories appear to ignore or at least minimize the significance of microlevel interactions. Microlevel interactions are formal, informal social and civic transactions that routinely occur in nearly every type of situation or setting. Virtually everyone who participates in society is a member of multiple communities, what is referred to in this study as circles of communities. These multiple communities offer researchers the opportunity to investigate why and how people place themselves in spatial, social, ideological, and experiential relationship or proximity to other community members and institutions. They are also where we are able to locate community despite the pace of change and transformation in contemporary society. The articulation of the decline of civil society as a social problem continues to privilege those with power and influence in American society. Academics, politicians, writers and editors, religious leaders, radio and talk show hosts and many others have been able to gain credibility, implement policies and impose normative standards for civic engagement. These standards are often used to identify insiders and outsiders in society. This research adds the voices of those who have been excluded from the discussion and recognizes them as experts both in terms of their own experiences and important contributors to the current body of social commentary and observations about community and associational living in modern America. / Thesis (PhD) — Boston College, 2008. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Sociology.

Thesis advisor: James Lubben / It has been shown that the effect of social networks and social support systems on health may be greater among immigrants who live away from their homeland and their natural social support systems. Despite the significance of social support systems, relevant research on minorities in the U.S. is limited. For this reason, the current cross-cultural study examined the pathways underlying different formations of social networks (kin vs. non-kin) and social support systems (emotional vs. instrumental), which affect depression symptoms and perceived general health among older Korean immigrants and non-Hispanic Caucasians in the United States. This analysis is based on the secondary data from the "Korean-American Elderly: Social Supports and Long-Term Care" study conducted in 1994. The data (n=424) were collected from non-Hispanic White Americans (n=201) and Korean immigrant elders (n=223) aged 65 and older residing in Southern California. Structural equation modeling (SEM) was used to test the proposed conceptual model designed to explain the direct and indirect relationships between social networks and social support on health outcomes. Empirical evidence from this study indicated different effect of one's social networks and social support on health by race/ethnicity. The result indicated that both kin and non-kin networks provided social support for Korean immigrants. Moreover, among social network measures, non-kin networks had a greater effect on social support for older Korean immigrants compared to kin networks. For non-Hispanic Caucasians, on the other hand, only kin network had a significant effect on social support systems. In addition, receiving instrumental support lowered the perceived general health among older non-Hispanic Caucasians. The work discussed in this paper pointed to the need to recognize the role of culture in assessing the effect of one's social networks and social support systems on health. This paper highlighted the characteristics of those older Korean-American and older non-Hispanic Caucasians who are most, as well as, least likely to benefit from social networks and social support systems. By utilizing the existing social networks and social support of diverse populations, we can improve overall health outcomes and serve the elderly community better. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Social Work. / Discipline: Social Work.

Thesis advisor: Sergio Alvarez / The recent explosion of online social networking through sites like Twitter, MySpace, Facebook has millions of users spending hours a day sorting through information on their friends, coworkers and other contacts. These networks also house massive amounts of user activity information that is often used for advertising purposes but can be utilized for other activities as well. Facebook, now the most popular in terms of registered users, active users and page rank, has a sparse offering of built-in filtering and predictive tools such as ``suggesting a friend'' or the ``Top News'' feed filter. However these basic tools seem to underutilize the information that Facebook stores on all of its users. This paper explores how to better use available Facebook data to create more useful tools to assist users in sorting through their activities on Facebook. / Thesis (BS) — Boston College, 2010. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Computer Science Honors Program. / Discipline: College Honors Program. / Discipline: Computer Science.