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Thanks to their increasing sophistication and popularity, mobile devices, in the form of smartphones and tablets, have become the fastest growing contributors to Internet traffic. Indeed, smartphones are projected to account for 50% of global Internet traffic by 2017, with the share of mobile video increasing to about 40% of total Internet traffic. As users embrace Internet streaming of video, several studies have found that a small decrease in video quality leads to a substantial increase in viewer abandonment and disengagement rates. To handle the explosive growth in video traffic, Adaptive HTTP streaming, which exploits the prevalence of commodity web servers and content distribution networks, has emerged as the key technology for delivering video to end users. Although a number of systems have been proposed for HTTP video streaming in traditional environments and for fixed clients, existing platforms for video streaming on mobile devices are still in their infancy and do not address the additional challenges often experienced by mobile clients: high fluctuations in network conditions, heterogeneous networking interfaces, multiple form-factors, and limited battery life. In this dissertation, we propose a number of solutions for improving the Quality of Experience of HTTP video streaming on mobile devices. We begin by evaluating the performance of several existing video quality adaptation schemes when deployed on mobile platforms. Through experiments with smartphones in wide-area environments, we assemble several key findings. First, we show that the high fluctuations in network throughput on cellular and Wi-Fi networks impose significant challenges for efficiently architecting the video adaptation scheme. Second, we find significant differences between the performance of the current state-of-the-art schemes in controlled experimental settings and their performance in mobile settings on key quality metrics such as inefficiency, instability, rebuffering ratio, and startup latency. We also find noticeable differences in the behavior of the schemes under Wi-Fi and cellular network access, with most of the schemes performing worse when the network access is cellular. Given these observations, we hypothesize on the possible causes of these inefficiencies. We also identify the best practices of existing schemes and key insights from experimental results that can serve as foundations for addressing many of the limitations. Armed with these measurement-driven insights, we propose a novel video quality adaptation scheme, called MASS, which is more robust to the vagaries of the wireless networking conditions. We implement and evaluate our solution on commodity Android smartphones, and demonstrate significant performance gains over existing schemes. To further improve the streaming experience, we introduce an extension to HTTP video streaming that leverages the synergy between social network participation and video streaming to optimize end-user Quality of Experience. Our system, called SDASH, integrates and applies well-known concepts such as cooperative caching, prefetching, and P2P streaming for reducing bitrate fluctuations and optimizing the viewing experience. Finally, we develop a general infrastructure for constructing temporally and spatially localized P2P communities of mobile devices sharing similar interests. The platform enables on-demand cooperation among mobile clients based on device context and client preferences. We use a concrete implementation of the mobile P2P infrastructure for evaluating the performance of SDASH. This dissertation addresses the challenges facing Adaptive HTTP Streaming under mobile networking conditions. Through experimentation with commodity mobile devices, we show that the proposed techniques for bitrate adaptation and cooperative streaming can significantly improve the video viewing experience.

Syftet med denna studie är att få kunskaper om hur lärplattformar och sociala nätverksverktyg stödjer undervisningen. Lärplattformar kallas för Learning Management Systems på engelska och förkortas med LMS. Det är ett samarbetsverktyg som används av lärare och studenter i undervisningen. Sociala nätverksverktyg används för att lärare ska kunna publicera sitt material via olika sociala nätverksverktyg, och de viktigaste verktygen är Facebook, bloggar och You-tube. De senaste åren har lärare börjat integrera sin undervisning med sociala nätverksverktyg för att de utökade kommunikationsmöjligheterna kan gynna lärandet.Denna studie handlar om användning av lärplattformar och sociala nätverksverktyg i högre utbildning. Uppsatsen bygger på en intervjustudie med lärare i två olika utbildningar på Högskolan Väst. De lärare som har intervjuats har olika erfarenheter av användning av lärplatt-formar och sociala nätverksverktyg. En av de slutsatser som har framkommit i studien är att diskussionsforum i alla lärplattformar inte är användbara. Ett annat resultat som har framkommit i denna uppsats är att via lärplattformen kan lärarna examinera studenter på ett bra och säkert sätt. Sociala nätverksverktyg och andra verktyg innehåller många fler funktioner och är mer tillgängliga för de flesta användare. Lärplattformar erbjuder en del möjligheter och att sociala nätverksverktyg erbjuder andra möjligheter. Detta innebär att man kan integrera olika verktygs-stöd för att läraren ska kunna göra sitt arbete på ett bra och flexibelt sätt. / The purpose of this study is to gain knowledge of Learning Management Systems (LMS) and how learning platforms and social networking tools supporting education. LMS is a tool used by teachers and students in education. Social networks are used by teachers for publishing their materials through various social networking tools, and the most used tools are Facebook, blogs, and YouTube. In recent years, teachers have been integrating their teaching with social network-ing tools for practical activities can be powerful tools for learning.This work is about the use of learning platforms and social networking tools in higher education. The work is based on some interviews of teachers in two different courses in the University West. The teachers who have been interviewed have different experiences on the use of learning platforms and social networking tools. One of the conclusions that have emerged in the study is that the discussion boards that is already available in the learning platforms are not useful. Something else that has emerged in this study is that by learning platform teachers can examine students in a good and safe way. Social networking tools and other tools contains many more features and is more available for most users. Another conclusion is that learning platforms offer some opportunities, and social networking tools offer other possibilities. This means that you can integrate different tool support for the teacher to be able to do their work in a good and flexible way.

It is of deep interest to researchers and practitioners in Information System (IS) to understand the efficacy of the traditional IS and economics theory in modern business environments such as online social networks. In the pursuit to understand such new IS phenomenon and address the gap in extant literature, my dissertation, identifies the strategies that the firms should incorporate in the presence of network effects; i.e., the increases in benefits accrued by a network user with an increase in the number of users, and its impact on consumer behavior. My first essay, challenges the traditional notion that network effects create a strong protective moat for the incumbent in network competition. I show that network effects are over rated in multi-homing setting, where users can co-exist across multiple networks under resource constraints. Over reliance on the strength of network effects by the incumbent firm in multi-homing setting, stems from extant economic theory that is applicable to single homing networks, where users has to choose one of the available networks. The first essay recommends strategies for the level of innovation and its time of delivery that firms should incorporate in order to survive and succeed in multi-homing environment. While the first essay focuses on multi-homing and the strength of network effects, the second essay revisits firm's preemption strategy in single homing setting with network effects, in order to prevent its users from migrating to a new entrant with better technology. I find that, for moderate levels of price and innovation competition, an incumbent with high reputation is better off being non-committal in its preemption. In contrast, committal preemption is apt for other combinations of reputation, innovation and price. While the first two essays focus on the impact of consumer behavior on firm strategies, the third essay delves into the impact of firm strategies on consumer behavior. In particular, I identify identity revelation policies that increase the number of successful transactions and collaborations in a socially embedded marketplace. The results imply that revealing social identities may be detrimental to negotiation and collaboration in a socially embedded marketplace -- a notion that is counter intuitive to networks that are inherently social. / text

published_or_final_version / Nursing Studies / Master / Master of Nursing in Advanced Practice

Between 2001 and 2011, a total of 509,809 new immigrants have migrated from Mainland China to Hong Kong on the One-way Permit for family reunification, in which 69.7% were female who are typically wives of Hong Kong permanent residents. How these marriage migrants integrate into Hong Kong society and the assessment of their impact to Hong Kong is becoming a pivotal issue. Many studies and surveys indicated that these marriage migrants have encountered tremendous difficulties during their course of immigration adaptation, and many have resulted in severe psychological stress. Extensive literature has empirically documented that social support facilitates immigrants’ ability to make use of relationships to buffer their adaptation challenges and to promote their integration into the new environment. Yet hardly any studies have examined the determinants and changes of social support among these marriage migrants within a longitudinal framework. The purpose of this study is to investigate the determinants of social support, including the structural, functional and the perception of social support. The “Social Support Mobilization Model” suggests that perceived stress leads to an increase in social support. On the contrary, the “Social Support Deterioration Model” suggests that persistent high level of stress erodes social support over time. This study test the Deterioration Model by examining the impact of lingering of stress levels on social support. Using a random sample of 211 Chinese marriage migrants from a two-year longitudinal secondary data, bivariate and multiple regression analyses were performed to examine the associations of social support with acculturation stress, persistent stress, psychological well-being, optimism and perceived neighborhood disorder. Findings indicated that marriage migrants have difficulties in re-establishing their social network outside their own community. Acculturation stress and psychological well-being were found to be the two most crucial factors affecting social support. Acculturation stress predicted both the structural and functional aspects of social support, but not the perceived social support. The psychological well-being, on the other hand, exerted significant influence on both the functional and perceived social support, but not on the structural social support. Results suggested that social support interventions should focus on alleviating acculturation stress, expanding social networking opportunity outside of their own immigrant community and enhancing psychological well-being. Besides, professional counseling and psychological support services should be provided to new immigrants, especially those who have experienced high level of stress. / published_or_final_version / Social Work and Social Administration / Doctoral / Doctor of Philosophy

Nowadays we are living in an era of rich data, not only in the sense of the amount of data, but also in the sense of various sources and content of data. Efficient search, management, and exploitation of data have, over decades, been a major direction of database research. In this thesis, three challenging problems are proposed and studied, targeting (i) time series data, (ii) user preference data, and (iii) location-based social network data, respectively, providing efficient solutions to corresponding real-life applications. First, durability queries are studied in historical time series databases, which identify objects that have durable quality over time. For example, a sociologist may be interested in the top 10 web search terms during the period of some historical events; the police may seek for vehicles that move close to a suspect 70% of the time during a certain time, etc. Such durable top-k (DTop-k) and durable k-nearest neighbor (DkNN) queries can be viewed as natural extensions of the standard snapshot top-k and NN queries to timestamped sequences of values or locations. Although their snapshot counterparts have been studied extensively, there is little prior work that addresses this new class of durability queries. Efficient and scalable algorithms are proposed based on novel indexing techniques. Next, an efficient solution to k-nearest neighbor search over top-m lists is investigated. A top-m list is a ranking of m items, typically representing some user’s preference over these items. For example, a user may have a list of her 10 most favourite books; the result from a search engine is typically a list of webpages ranked according to their relevance to some keywords. The search problem aims at extracting k top-m lists from the database that are the “closest” to some query list where the closeness is evaluated using commonly used measures such as the Fagin’s intersection metric, Spearman’s footrule, Kendall’s tau, etc. Despite of the importance of such queries, there’s little prior work suggesting any efficient solution. In this thesis, a unified framework is proposed to answer such queries efficiently. Finally, the problem of top-N venue recommendation in location-based social networks (LBSNs) is studied, which recommends new venues to users. As an increasingly larger number of users partake in LBSNs, the recommendation problem in this setting has attracted significant attention in research and in practical applications. The detailed information about past user behavior that is traced by the LBSN differentiates the problem significantly from its traditional settings. The spatial nature in the past user behavior and also the information about the user social interaction with other users, provide a richer background to build a more accurate and expressive recommendation model. Although there have been extensive studies on recommender systems working with user-item ratings, GPS trajectories, and other types of data, there are very few approaches that exploit the unique properties of the LBSN user check-in data. In this thesis, effective and efficient algorithms that create recommendations are proposed based on such properties. / published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy

This research explores how Lebanese women's rights activists use their kinship system to pursue citizenship rights and political recognition. Building on social movements, social capital, and feminist theories, I argue that Lebanese women's rights activists leverage support from their kin groups and adhere to the behavioral norms set by the kinship system in order to gain access, build capacity and advance their movement's goals and strategies. In investigating the impact of being embedded in--or autonomous from--kinship structure on activism, my research suggests that Lebanese women's rights activists interact with their kin groups at three levels. Firstly, at the level of becoming an activist, some women obtain direct support and encouragement from their nuclear and extended family, while others rise through alternative networks such as membership in a political party or a professional union. At the personal strategies level, some activists utilize their family support and kinship networks to establish their activist identities and facilitate their civic engagement, while others use collegial and professional networks. Finally, on the organizational level, women's rights organizations pursue women's empowerment in the context of their role in the family, dissolving the divide between women's rights in the sphere of legal equality and women's rights within the family. Women's relation to kinship is significant in explaining how they form their activist identity and construct their activism, regardless whether they use embedded or autonomous strategies. Activists receive empowerment and support from the family in advancing their goals and consider family members as important forces in shaping their journeys to activism. In the same vein, the kinship system contributes to determining actors' social status at the outset; its networks potentially grant activists access to the public sphere; and its name and ties endows activists with public trust and respect. Lebanese activists expand on the capabilities provided for them by their kin groups to enhance women’s status in their public as well as private roles. / text

<p>Social capital has so far been suggested to enhance the career outcomes of disadvantaged immigrants by compensating for their lack of human capital. Contrastingly, by examining labor market outcomes by immigrant groups, my dissertation argues that social capital can actually serve as a source of disadvantages for immigrants in the labor market, especially for a socially disadvantaged immigrant group like Mexican immigrants. Specifically, the dissertation proposes three kinds of social capital processes through which social status and network processes interplay to disadvantage disproportionately a low-status immigrant group in the job attainment process: access, activation, and return deficit of social capital. Using data from the 2005 U.S. Social Capital-USA survey, I examine these three kinds of social capital deficit across three ethnic immigrant groups: Mexican, non-Mexican Hispanic, and non-Hispanic immigrants. The first chapter explores the inequality of social capital across immigrant groups. The result shows that among the three immigrant groups, Mexican immigrants are the only immigrant group who have smaller, less diverse networks than the native-born. This access deficit of social capital for Mexican immigrants is driven primarily by their relative lack of human capital compared with other immigrant groups. The second chapter investigates whether ethnic enclaves constrain the access to social capital of enclave immigrants. The result shows that the constraining effect of ethnic enclaves on the social capital building of enclave immigrants is found only for the ethnic enclave of Mexican immigrants. This is because the ethnic enclaves of disadvantaged immigrants facilitate social connections to other coethnic enclave immigrants with similar socioeconomic traits, while constraining them from extending their networks beyond the enclaves. The access deficit of social capital for Mexican immigrants will eventually aggravate their job prospects because they cannot mobilize social capital for their job finding as much as other immigrant groups do. The third chapter examines the activation and mobilization of social capital in the job attainment process across immigrant groups. The result shows that Mexican immigrants activate and reap the benefit from mobilizing social capital for their job finding in ways that are different from those of the native-born as well as the high-status immigrant group. Due to their access deficit of social capital and negative stereotypes about them, Mexican immigrants are obliged to use a less rewarding job search method (i.e., using information passed from job contacts) rather than use a more rewarding job search method (i.e., using invitations from job contacts). Although Mexican immigrants benefit to some degrees from using information passed from job contacts in getting low-tier occupations, their heavy reliance on such a job search method can also prevent them from attaining middle- or top-tier occupations. By illuminating these serial processes of social capital in the job attainment for disadvantaged immigrants, my dissertation, therefore, sheds light on a new role of social capital as a source of immigrant disadvantages in the labor market.</p> / Dissertation

I takt med att användandet av sociala nätverk ökar så sker även en ökning av marknadsföring och reklam på dessa plattformar. Det största sociala nätverket idag är Facebook som har cirka 1,5 miljarder användare. Företag har börjat förstå vikten av att finnas på Facebook men de måste lära sig hur och vilken form av marknadsföring som är mest lämpad att använda på den plattformen.Syftet med denna studie är att försöka bringa klarhet i hur Facebookanvändare påverkas av de olika marknadsföringsformerna påtvingad marknadsföring och tillståndsmarknadsföring, samt hur de reagerar på reklam på Facebook och om det finns någon skillnad mellan män och kvinnor. För att besvara syftet genomfördes två fokusgrupper som bestod av både män och kvinnor och resultatet av dessa är att tillståndsmarknadsföring är den mest lämpade metoden för företag att använda men att det finns en förståelse för att båda former av marknadsföring finns. Utifrån studien har vi tagit fram 3 punkter som företag bör ha i åtanke vid marknadsföring på Facebook - 1) företag måste tänka över vilken marknadsföringsform de använder och varför, 2) segmentering av användare för att nå ut till rätt målgrupp för att effekten av reklamen ska bli så hög som möjligt och 3) för att reklam ska fånga användares uppmärksamhet är det viktigt att den innehåller intressant text med passande bilder. Resultaten av studien är inte generaliserbara och därför kan ytterligare studier om fenomenet behövas genomföras för att ge en mer rättvis bild. / As the use of social networks increases so does the use of marketing and advertising on these networks. The largest social network today is Facebook, which has about 1.5 billion users. Companies have begun to understand the importance of using Facebook, but they must learn how they should use Facebook as a marketing channel and which form of marketing that is most suitable to use on the platform.The purpose of this study is to try to clarify how Facebook users are affected by the different forms of marketing, forced marketing and permission marketing, and how they react to advertising on Facebook and if there is a difference between men and women. The purpose has been answered by putting together two focus groups consisting of both men and women. The results from these groups shows that permission marketing is the most suitable method for companies to use, but it also shows that there is an understanding that both forms of marketing exists. Based on this study, we have found 3 important things that companies should keep in mind when they use Facebook for marketing. 1) Companies must consider which form of marketing they should use and why, 2) segmentation of users to reach out to the right audience, to make the effect of advertising as high as possible, and 3) to capture users’ attention, it is important that the advertisement contains interesting text with suitable images. It’s not possible to generalize the results of the study and therefore further studies on the phenomenon are needed to provide a more accurate picture. This essay is written in Swedish.