Social phenomena have been studied extensively in small scales by social scientists. With the increasing popularity of Web 2.0 and online social networks/media, a large amount of data on social phenomena have become available. In this dissertation we study online social phenomena such as social influence in social networks in various contexts. This dissertation has two major components: 1. Identifying and characterizing online social phenomena 2. Leveraging online social phenomena for economic and commercial purposes. We begin the dissertation by developing multi-level revenue sharing schemes for viral marketing on social networks. Viral marketing leverages social influence among users of the social network. For our proposed models, we develop results on the computational complexity, individual rationality, and potential reach of employing the Shapley value as a revenue sharing scheme. Our results indicate that under the multi-level tree-based propagation model, the Shapley value is a promising scheme for revenue sharing, whereas under other models there are computational or incentive compatibility issues that remain open. We continue with another application of social influence: social advertising. Social advertising is a new paradigm that is utilized by online social networks. Social advertising is based in the premise that social influence can be leveraged to place ads more efficiently. The goal of our work is to understand how social ads can affect click-through rates in social networks. We propose a formal model for social ads in the context of display advertising. In our model, ads are shown to users one after the other. The probability of a user clicking an ad depends on the users who have clicked this ad so far. This information is presented to users as a social cue, thus the click probability is a function of this cue. We introduce the social display optimization problem: suppose an advertiser has a contract with a publisher for showing some number (say B) impressions of an ad. What strategy should the publisher use to show these ads so as to maximize the expected number of clicks? We show hardness results for this problem and in light of the general hardness results, we develop heuristic algorithms and compare them to natural baseline ones. We then study distributed content curation on the Web. In recent years readers have turned to the social web to consume content. In other words, they rely on their social network to curate content for them as opposed to the more traditional way of relying on news editors for this purpose -- this is an implicit consequence of social influence as well. We study how efficient this is for users with limited budgets of attention. We model distributed content curation as a reader-publisher game and show various results. Our results imply that in the complete information setting, when publishers maximize their utility selfishly, distributed content curation reaches an equilibrium which is efficient, that is, the social welfare is a constant factor of that under an optimal centralized curation. Next, we initiate the study of an exchange market problem without money that is a natural generalization of the well-studied kidney exchange problem. From the practical point of view, the problem is motivated by barter websites on the Internet, e.g., swap.com, and u-exchange.com. In this problem, the users of the social network wish to exchange items with each other. A mechanism specifies for each user a set of items that she gives away, and a set of items that she receives. Consider a set of agents where each agent has some items to offer, and wishes to receive some items from other agents. Each agent would like to receive as many items as possible from the items that she wishes, that is, her utility is equal to the number of items that she receives and wishes. However, she will have a large dis-utility if she gives away more items than what she receives, because she considers such a trade to be unfair. To ensure voluntary participation (also known as individual rationality), we require the mechanism to avoid this. We consider different variants of this problem: with and without a constraint on the length of the exchange cycles and show different results including their truthfulness and individual rationality. In the other main component of this thesis, we study and characterize two other social phenomena: 1. friends vs. the crowd and 2. altruism vs. reciprocity in social networks. More specifically, we study how a social network user's actions are influenced by her friends vs. the crowd's opinion. For example, in social rating websites where both ratings from friends and average ratings from everyone is available, we study how similar one's ratings are to each other. In the next part, we aim to analyze the motivations behind users' actions on online social media over an extended period of time. We look specifically at users' likes, comments and favorite markings on their friends' posts and photos. Most theories of why people exhibit prosocial behavior isolate two distinct motivations: Altruism and reciprocity. In our work, we focus on identifying the underlying motivations behind users' prosocial giving on social media. In particular, our goal is to identify if the motivation is altruism or reciprocity. For that purpose, we study two datasets of sequence of users' actions on social media: a dataset of wall posts by users of Facebook.com, and another dataset of favorite markings by users of Flickr.com. We study the sequence of users' actions in these datasets and provide several observations on patterns related to their prosocial giving behavior.

The main purpose of this thesis is to develop a malware threat avoidance model for users of online social networks (OSNs). To understand the research domain, a comprehensive and systematic literature review was conducted and then the research scope was established. Two design science iterations were carried out to achieve the research aim reported in this thesis. In the first iteration, the research extended the Technology Threat Avoidance Theory (TTAT) to include a unique characteristic of OSN - Mass Interpersonal Persuasion (MIP). The extended model (TTAT-MIP), focused on investigating the factors that needs to be considered in a security awareness system to motivate OSN users to avoid malware threats. Using a quantitative approach, the results of the first iteration suggests perceived severity, perceived threat, safeguard effectiveness, safeguard cost, self-efficacy and mass interpersonal persuasion should be included in a security awareness system to motivate OSN users to avoid malware threats. The second iteration was conducted to further validate TTAT-MIP through a Facebook video animation security awareness system (referred in this thesis as Social Network Criminal (SNC)). SNC is a Web-based application integrated within Facebook to provide security awareness to OSN users. To evaluate TTAT-MIP through SNC, three research techniques were adopted: lab experiments, usability study and semi-structured interviews. The results suggest that participants perceived SNC as a useful tool for malware threat avoidance. In addition, SNC had a significant effect on the malware threat avoidance capabilities of the study participants. Moreover, the thematic analysis of the semi-structured interviews demonstrated that the study participants' found SNC to be highly informative; persuasive; interpersonally persuasive; easy to use; relatable; fun to use; engaging; and easy to understand. These findings were strongly related to the constructs of TTAT-MIP. The research contributes to theory by demonstrating a novel approach to design and deploy security awareness systems in a social context. This was achieved by including users' behavioural characteristic on the online platform where malware threats occur within a security awareness system. Besides, this research shows how practitioners keen on developing systems to improve security behaviours could adopt the TTAT-MIP model for other related contexts.

陳建. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 183-194) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in Chinese and English. / Chen Jian.

This study discusses Facebook as a social network site and a social media application. It compares perceived emotional support, general life stress, and media affordance-based stress from two participant samples - one that reported using the Facebook desktop site most frequently to reach out for emotional support, and one that reported using the mobile application. The media affordance measure asked participants if perceiving a media affordance was more likely to increase or decrease their stress. In both samples, persistence was more likely to decrease stress, and personalization was more likely to increase stress. On the Facebook Desktop site, searchability was more likely to increase stress. On the Facebook mobile application, pervasiveness was more likely to decrease stress, and association to increase stress. When comparing affordances between samples, there were no significant differences found. When comparing samples, the Facebook mobile application users reported higher life stress, but there was no difference found in perception of emotional support. Within samples, there was no correlation between perceived stress and perceived emotional support. Finally, there was a significant correlation found between perception of emotional support on the site and frequency of reaching out for emotional support. On the Facebook desktop site, users reached out by public post and by private message significantly less frequently if they perceived a higher level of emotional support to be available on the site. On the Facebook mobile application, users reached out by public post significantly less frequently if they perceived a higher level of emotional support to be available on the application. No correlation was found for reaching out by private message on the Facebook mobile application.

published_or_final_version / Social Work / Master / Master of Social Sciences

No description available.

Orientador: Prof. Dr. Carlos Kamienski / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia da Informação, 2015.

Social network sites have recently become extremely popular online destinations as they offer users easy ways to build and maintain their relationships with each other. Consequently, students, lecturers, teachers, parents and businesses are using these tools to communicate with each other in a fast and cost-effective manner. However, literature suggests that the full potential of social network sites has not yet been revealed since users are still battling to overcome the various negative characteristics surrounding these sites. A framework for appropriate use of these sites is needed so that users are able to overcome these negative aspects, allowing them to be more effective and use the sites successfully. The goal of this research is to construct a framework for perceived successful use of social computing tools in educational institutions. This framework will include critical success factors that need to be adopted by users in order to develop the positive aspects of social computing, while at the same time overcoming the disadvantages experienced by users. Factors for successful use were derived from the literature and consolidated into a theoretical framework in order to understand the factors that drive successful use of social network sites. Measures used to test successful use of social network sites were also derived from these sources and were included in the same theoretical framework; these measures allow users to evaluate the extent of perceived successful use of social network sites. This framework was tested empirically by means of a pilot study and online survey, and revised according to the results of the survey. The factors were identified using Cronbach alpha coefficients (in the pilot study) and exploratory factor analysis to confirm the reliability of the scales developed. Pearson product-moment correlation coefficient analysis, t-tests and Pearson Chi-Square tests were used to measure the relationships amongst the variables in the framework proposed in this research. The factors influencing perceived successful use of social network sites were identified by the empirical study as: • Privacy and Security Settings need to be enabled. These are split into: - Settings: content that users allow others to see - Viewers: people who are allowed onto a user's profile • It is necessary for users to practise Legal and Acceptable Activities when using social network sites • Suspect Information needs to be checked before sharing it with others • Personal and Professional Time needs to be separated to ensure that work is completed before social activities occur • Users need to practise Professional and Ethical Behaviour • Users need to have a Positive Attitude when using social network sites • Usability of sites affects their success. This includes: - technical capacity (broadband) - ease of use - functionality (range of features and functions) • Current and Controversial Issues need to be discussed on social network sites. The extent to which social network sites are being used successfully can be evaluated by the presence of the following measures: • Range of Content must be available to users. This includes: - Content displayed on profiles - Viewers able to visit profiles • Visitors Behaviour is monitored and no unwanted visitors are present users' profiles • Social Contracts found on sites are followed by users • Critical Thinking Skills and Accurate Information are displayed by users • Work is completed before social activities occur on sites • A Variety of Users is present on sites • Collaboration between people as well as variety of opinions exist on sites • Social Capital (well-being) is present after users have been on sites • Learning and Advising Skills are enhanced on sites. The framework developed provides users with a useful instrument to overcome the negative characteristics associated with social network sites. If used successfully, social network sites can offer lecturers and students a unique method to develop their relationship, creating a positive learning experience.

Problem alcohol use has far-reaching economic, intra-, and interpersonal consequences. One particularly hazardous form of drinking pertains to the consumption of alcohol as a means of regulating stress, or drinking to cope. As such, it is critical to identify pathways through which stress-related alcohol use occurs, as well as protective factors which may mitigate the aforementioned consequences. To achieve this, I conducted three studies examining these topics at multiple levels of analysis among two at risk populations for engaging in problematic drinking: College students and military service members. Study 1 is a published manuscript examining the association between personality, a known vulnerability factor, and daily alcohol use among college students. This study tested whether these associations were mediated by the utilization of daily coping behaviors. Study 2 is an exploration of the association between of post-traumatic stress symptoms (PTSS) and alcohol involvement among employed service members. I conducted conditional process analysis to determine whether the indirect association of PTSS on alcohol involvement through coping motivations was conditional on one's perceived level of social support. Finally, Study 3 examined how daily experiences of occupational stressors influence alcohol consumption using a subsample of married and cohabiting participants from Study 2. I tested the moderating roles of coping motives and more adaptive, support-based coping strategies on work stress-daily drinking associations. Together, these studies help elucidate why individuals typically drink when stressed, who may be more apt to do so, and under what conditions these effects hold true.

Social Interaction Technologies (SIT) have broadened the horizon of communication in terms of the way people are able to communicate. It is now possible to interact with others across the world and engage in numerous activities ranging from dating to political movements, hobbies and even professions (Chigona, Chigona, Ngqokelela, & Mpofu, 2009). Adolescents and pre-adolescents especially are inclined to make use of SIT in their social lives with the most popular mode of communication, apart from email, being instant messaging (IM) (Brown, Mounts, Lamborn, & Steinberg, 1993; Bryant, Sanders-Jackson, & Smallwood, 2006; Madden & Rainie, 2003). Adolescents tend to use IM regularly as a tool to maintain relationships and girls especially, use it as a tool to socialise (Jennings & Wartella, 2004; Lenhart, Rainie, & Lewis, 2001). The mobile phone or cell phone, which is another example of an SIT-based communication, has become an established medium of technical, social and commercial communication in South Africa. It has given rise to the development and vast growth of a mobile youth culture who consider it an essential tool for communicating (Bosch, 2008). In South Africa, instant messages may be sent via mobile phone using one of two methods: MXit and the SMS (short messaging service). MXit and the SMS are considered convenient tools of communication as an ongoing conversation in the form of a text message may be maintained in the present (Yoshii, Matsuda, Habuchi, Dobashi, Iwata, & Kin, 2002).