With the ubiquity of broadband, wireless and mobile networking and the diversity of user-driven social networks and social channels, we are entering an information age where people and vehicles are connected at all times, and information and influence are diffused continuously through not only traditional authoritative media such as news papers, TV and radio broadcasting, but also user-driven new channels for disseminating information and diffusing influence. Social network users and mobile travelers can influence and be influenced by the social and spatial connectivity that they share through an impressive array of social and spatial channels, ranging from friendship, activity, professional or social groups to spatial, location-aware, and mobility aware events. In this dissertation research, we argue that spatial alarms and activity-based social networks are two fundamentally new types of information and influence diffusion channels. Such new channels have the potential of enriching our professional experiences and our personal life quality in many unprecedented ways. For instance, spatial alarms enable people to share their experiences or disseminate certain points of interest by leaving location-dependent greetings, tips or graffiti and location dependent tour guide to their friends, colleagues and family members. Through social networks, people can influence their friends and colleagues by the activities they have engaged, such as reviews and blogs on certain events or products. More interestingly, the power of such spatial and social diffusion of information and influence can go far beyond our physical reach. People can utilize user-generated social and spatial channels as effective means to disseminate information and propagate influence to a much wider and possibly unknown range of audiences and recipients at any time and in any location. A fundamental challenge in embracing such new and exciting ways of information diffusion is to develop effective and scalable models and algorithms as enabling technology and building blocks. This dissertation research is dedicated towards this ultimate objective with three novel and unique contributions. First, we develop an activity driven and self-configurable social influence model and a suite of computational algorithms to compute and rank social network nodes in terms of activity-based influence diffusion over social network topologies. By activity driven we mean that the real impact of social influence and the speed of such influence propagation should be computed based on the type, the amount and the time window of the activities performed by a social network node in addition to its social connectivity (social network topology). By self-configurable we mean that the diffusion efficiency and effectiveness are dynamically adapted based on the settings and tunings of multiple spatial and social parameters such as diffusion context, diffusion location, diffusion rate, diffusion energy (heat), diffusion coverage and diffusion incentives (e.g., reward points), to name a few. We evaluate our approach through datasets collected from Facebook, Epinions, and DBLP datasets. Our experimental results show that our activity based social influence model outperforms existing topology-based social influence model in terms of effectiveness and quality with respect to influence ranking and influence coverage computation. Second, we further enhance our activity based social influence model along two dimensions. At first, we use a probabilistic diffusion model to capture the intrinsic properties of social influence such that nodes in a social network may have the choice of whether to participate in a social influence propagation process. We examine threshold based approach and independent probabilistic cascade based approach to determine whether a node is active or inactive in each round of influence diffusion. Secondly, we introduce incentives using multi-scale reward points, which are popularly used in many business settings. We then examine the effectiveness of reward points based incentives in stimulating the diffusion of social influences. We show that given a set of incentives, some active nodes may become more active whereas some inactive nodes may become active. Such dynamics changes the composition of the top-k influential nodes computed by activity-based social influence model. We make several interesting observations: First, popular users who are high degree nodes and have many friends are not necessarily influential in terms of spawning new activities or spreading ideas and information. Second, most influential users are more active in terms of their participation in the social activities and interactions with their friends in the social network. Third, multi-scale reward points based incentives can be effective to both inactive nodes and active nodes. Third, we introduce spatial alarms as the basic building blocks for location-dependent information sharing and influence diffusion. People can share and disseminate their location based experiences and points of interest to their friends and colleagues in the form of spatial alarms. Spatial alarms are triggered and delivered to the intended subscribers only when the subscribers move into the designated geographical vicinity of the spatial alarms, enabling delivering and sharing of relevant information and experience at the right location and the right time with the right subscribers. We studied how to use locality filters and subscriber filers to enhance the spatial alarm processing using traditional spatial indexing techniques. In addition, we develop a fast spatial alarm indexing structure and algorithms, called Mondrian Tree, and demonstrate that the Mondrian tree enabled spatial alarm system can significantly outperform existing spatial indexing based solutions such as R-tree, $k$-d tree, Quadtree. This dissertation consists of six chapters. The first chapter introduces the research hypothesis. We describe our activity-based social influence model in Chapter 2. Chapter 3 presents the probabilistic social influence model powered with rewards incentives. We introduce spatial alarms and the basic system architecture for spatial alarm processing in Chapter 4. We describe the design of our Mondrian tree index of spatial alarms and alarm free regions in Chapter 5. In Chapter 6 we conclude the dissertation with a summary of the unique research contributions and a list of open issues closely relevant to the research problems and solution approaches presented in this dissertation.

Online communities are growing at a phenomenal rate and with the large number of users these communities contain, attackers are drawn to exploit these users. Denial of information (DoI) attacks and information leakage attacks are two popular attacks that target users on online communities. These information based attacks are linked by their opposing views on low-quality information. On the one hand denial of information attacks which primarily use low-quality information (such as spam and phishing) are a nuisance for information consumers. On the other hand information leakage attacks, which use inadvertently leaked information, are less effective when low-quality information is used, and thus leakage of low-quality information is prefered by private information producers. In this dissertation, I introduce techniques for preventing abuse against these attacks in online communities using meta-model classification and information unification approaches, respectively. The meta-model classification approach involves classifying the ``connected payload" associated with the information and using the classification result for the determination. This approach allows for detection of DoI attacks in emerging domains where the amount of information may be constrained. My information unification approach allows for modeling and mitigating information leakage attacks. Unifying information across domains followed by a quantificiation of the information leaked, provides one of the first studies on users' susceptibality to information leakage attacks. Further, the modeling introduced allows me to quantify the reduced threat of information leakage attacks after applying information cloaking.

Thesis supervisor: Judy Polumbaum. Includes bibliographic references (p. 232-241).

M. Tech. Business Information Systems / The growing trends and the rapid developments of technological innovation have led to a new way of communication. These developments have seen individuals and organizations spending a lot of money on technological devices, software and applications much higher than ever before. On the other hand, institutions of learning are also advancing with technological innovations by shifting away from the face-to-face teaching and communicating with learners, to the use of Learning Management Systems (LMS). Amidst these challenges, these institutions of learning could leverage on freely available social networks for communication and for teaching and learning. However, these transitions have been impeded by many factors that need to be explored in order to adopt social networks for teaching and learning. The foremost objective of this study was to develop a framework for the adoption of social networks for teaching and learning at high schools.

M. Tech. Business Information Systems / Focuses on tackling the lack of access to learning content and social resources in the higher learning environment of South Africa (SA). This research is important because South African institutions of higher learning are English language environments dominated by underprepared learners and overpopulated classrooms. Moreover, the country has lately seen increased numbers of learners entering higher learning institutions demonstrating a fair rate of acceptance of social media sites (SMS).

Thesis (MTech. degree in Business Information Systems.)--Tshwane University of Technology, 2010. / This research addresses how mobile learning by means of a virtual community of practice can facilitate interaction and knowledge sharing amongst contact university learners as they traverse varied learning environments. Using Activity theory and the theory of social presence, the research aimed to provide an informed understanding of virtual communities of practice and how they manifest in a mobile learning environment. In this dissertation, virtual communities of practice are argued to effectively facilitate personalized learning support in an environment where learning is not confined to particular places. Importantly, virtual communities of practice are fundamentally modeled by awareness of context and social presence. Informed by empirical evidence gathered through a Contextual Inquiry method, a field research framework that depends on interaction with users in the context of their work, this study shows how mobile learners in a typical South African university could be afforded personalized academic support as they traverse varied learning environments.

Social media have been growing rapidly in recent years thanks to the innovations of social networking sites (SNS) such as Facebook and Twitter, both of which originated in the United States. Currently, SNS and other social media have become global phenomena. This report aims to study the features of SNS that prosper in the U.S., Japan, and China. Through a comparative analysis of the similarities and differences among the top SNS players in each of the three countries, it is possible to identify unique characteristics of each nation’s social networking landscape. The SNS market in the U.S. is relatively mature, while the social networking population is growing in Japan and China. However, contrary to the expectations of some, the Japanese and Chinese social networking landscapes appear to be quite different from one another with regard to SNS usage, despite Japan and China’s similar cultural backgrounds and geographical proximity. / text

Web and mobile technologies have had such profound impact that we have witnessed significant evolutionary changes in our social, economic and cultural activities. In recent years, online social networking sites such as Twitter, Facebook, Google+, and LinkedIn have gained immense popularity. Such social networks have led to an enormous explosion of network-centric data in a wide variety scenarios, posing unprecedented analytical and computational challenges to MIS researchers. At the same time, the availability of such data offers major research opportunities in various social computing and analytics areas to tackle interesting questions such as: - From a business and marketing perspective, how to mine the novel datasets of online user activities, interpersonal communications and interactions, for developing more successful marketing strategies? - From a system development perspective, how to incorporate massive amounts of available data to assist online users to find relevant, efficient, and timely information? In this dissertation, I explored these research opportunities by studying multiple analytics problems arose from the design and use of social networking services. The first two chapters (Chapter 2 and 3) are intended to study how social network can help to derive a better estimation of customer lifetime value (CLV), in the social gaming context. In Chapter 2, I first conducted an empirical study to demonstrate that friends' activities can serve as significant indicators of a player's CLV. Based on this observation, I proposed a perceptron-based online CLV prediction model considering both individual and friendship information. Preliminary results have shown that the model can be effectively used in online CLV prediction, by evaluating against other commonly-used benchmark methods. In Chapter 3, I further extended the metric of traditional CLV, by incorporating the personal influences on other customers' purchase as an integral part of the lifetime value. The proposed metric was illustrated and tested on seven social games of different genres. The results showed that the new metric can help marketing managers to achieve more successful marketing decisions in user acquisition, user retention, and cross promotion. Chapter 4 is devoted to the design of a recommendation system for micro-blogging. I studied the information diffusion pattern in a micro-blogging site (Twitter.com) and proposed diffusion-based metrics to assess the quality of micro-blogs, and leverage the new metric to implement a novel recommendation framework to help micro-blogging users to efficiently identify quality news feeds. Chapter 5 concludes this dissertation by highlighting major research contributions and future directions.

Tyrimo tikslas yra aptarti vaiko teisių galimus pažeidimus ir prevenciją internetiniuose socialiniuose tinkluose. Magistro darbe analizuojamas vaiko teisių pažeidimų internetiniuose socialiniuose tinkluose prevencijos organizavimas ir įgyvendinimas gimnazijoje, siekiant išsiaiškinti esamą situaciją, kad būtų imtasi konkrečių veiksmų plano. Tyrimas buvo organizuojamas 2012 metų gruodžio 17-21 dienomis. Anketinės apklausos metodu ištirti 170 gimnazijos I ir II klasės mokiniai (iš jų 88 pirmokai ir 82 antrokai) bei 35 pedagogai ir kiti gimnazijos darbuotojai, dirbantys šioje gimnazijoje. Tyrimo rezultatai parodė, jog gimnazistai suvokia internetinių socialinių tinklų grėsmes, dažnai su jomis susiduria pažeisdami savo teises. Šios grėsmės internete juos neramina, o susidūrę su jomis jie linkę apie tai niekam nepasakoti. Mokiniai jaučiasi turį pakankamai žinių ir įgūdžių bendravimui internete, gebėjimų siekiant užtikrinti saugų darbą internete. Atlikta tyrimų rezultatų analizė atskleidė šiuos vaiko teisių pažeidimų internetiniuose socialiniuose tinkluose prevencijos gimnazijoje organizavimo ypatumus: gimnazijoje vis dėlto nepakankamai vykdoma įtaigi prevencinė veikla, gimnazijos bendruomenė šviesdama mokinius apie jų saugų darbą internete apsiribojama gimnazistų paviršutinišku informavimu ir švietimu, ne visi pedagogai šviečia ir informuoja mokinius apie jų saugų darbą internete. Aktyviausiai prevenciją vykdo dalykų pedagogai, integruotų pamokų ir klasės auklėtojai organizuotų... [toliau žr. visą tekstą] / Research objective is to review violations of children’s rights in online social networks. In MA thesis there is being analysed the prevention management and implementation of violations of children‘s rights in gymnasium having the aim to clarify a present situation in order the efficient action plan to be created. The research was conducted 17-21 December in 2012. Using the method of questionnaire survey there were interviewed 170 gymnasium‘s first and second graders (out of them 88 first graders and 82 second graders), 35 teachers and other employees who work in this gymnasium. Research outcome showed that gymnasium students realise threats of social networks and face them violating their rights. These threats on the Internet make them feel anxious and while facing them they are tend not to talk to anybody. Students feel quite confident in having knowledge and skills to communicate on the Internet and abilities to ensure safe work online. The analysis of research findings revealed particularities of prevention management in the gymnasium concerning violations of children‘s rights in social networks: impellent prevention activity is not sufficient enough in the gymnasium; the gymnasium community educating students about their safe work online narrow to shallow spreading of information and education; not all teaching staff educate and inform students about their safe work online. The most active prevention is organised by subjects’ teachers during integrative lessons and... [to full text]

South Africa, since 1994, has developed both politically and technologically resulting in an opening of communications both locally and globally. The 2009 national elections had been earmarked as a 'make or break' milestone for the political and social future of the young democracy. This election occurred amidst media analysts‘ concerns for the level of freedom of expression allowed to traditional forms of the South African media. New media, however, is not at present subject to the same regulations. Although a few cases of slander relating, for example, to Facebook have occurred, ephemeral cyber space appears to enjoy a greater degree of freedom of expression than the press and broadcast media. As a result the ability of these traditional forms of media to function effectively as a public sphere may be questioned, and some theorists claim that the Internet may offer an alternative medium for this function. This thesis looks at the potential of online communities to facilitate democratic expression by analysing a Facebook newsgroup text at the time of the election. In my exploration of the Facebook newsgroup Help us stop Jacob Zuma from becoming SA's next President I have analysed the text using two qualitative approaches. The critical discourse analysis traces competing South African discourses relating to the myths of the inherent violence of black men and the inherent racism of whites, the topics of crime and violence, Jacob Zuma and South Africanness. This approach‘s theoretical guidelines enforced a more objective view of the text, although interpretive methods in general grapple with subjectivity at a more observable level than do quantitative methods. The ethnographic hermeneutic component of the research is aimed at "making the obscure plain" (Blaikie, 1993: 28, cited in Neuman, 1997: 68) in the text, as well as documenting the inner workings of the online community and its relation to South African issues at the time of the national election. The findings are then measured against public sphere theory from Habermas' conception of the bourgeois public sphere to revisionist accounts (Fraser, 1997 and McKee, 2005) / Thesis (M.A.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.