Browsing by Subject "social"
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Item Community-Oriented Models and Applications for the Social Web(2012-07-16) Kashoob, Said Masoud AliThe past few years have seen the rapid rise of all things "social" on the web from the growth of online social networks like Facebook, to user-contributed content sites like Flickr and YouTube, to social bookmarking services like Delicious, among many others. Whereas traditional approaches to organizing and accessing the web?s massive amount of information have focused on content-based and link-based approaches, these social systems offer rich opportunities for user-based and community-based exploration and analysis of the web by building on the unprecedented access to the interests and perspectives of millions of users. We focus here on the challenge of modeling and mining social bookmarking systems, in which resources are enriched by large-scale socially generated metadata (?tags?) and contextualized by the user communities that are associated with the resources. Our hypothesis is that an underlying social collective intelligence is embedded in the uncoordinated actions of users on social bookmarking services, and that this social collective intelligence can be leveraged for enhanced web-based information discovery and knowledge sharing. Concretely, we posit the existence of underlying implicit communities in these social bookmarking systems that drive the social bookmarking process which can provide a foundation for community-based organization of web resources. To that end, we make three contributions: ? First, we propose a pair of novel probabilistic generative models for describing and modeling community-oriented social bookmarking. We show how these models enable effective extraction of meaningful communities over large real world social bookmarking services. ? Second, we develop two frameworks for community-based web information browsing and search that are based on these community-oriented social bookmarking models. We show how both achieve improved discovery and exploration of the social web. ? Third, we introduce a community evolution framework for studying and analyzing social bookmarking communities over time. We explore the temporal dimension of social bookmarking and explore the dynamics of community formation, evolution, and dissolution. By uncovering implicit communities, putting them to use in an application scenario (search and browsing), and analyzing them over time, this dissertation provides a foundation for the study of how social knowledge networks are self-organized, a deeper understanding and appreciation of the factors impacting collective intelligence, and the creation of new information access algorithms for leveraging these communities.Item Social Context of Gray Whale Eschrichtius robustus Sound Activity(2012-07-16) Charles, SarahThis thesis examines sound production of eastern gray whales (Eschrichtius robustus) in the wintering lagoons to determine whether sound use is a function of social context. Proportions of sounds used, parameters of each sound class, and rates of sounds were compared among social contexts. Data revealed the strong possibility of context-specific use for particular sound classes. Additionally, sound parameters and rates of production varied by social context. These results reflect similar variations in gray whale repertoire throughout their range that may be due to changes in social and behavioral contexts. Gray whale sounds are classified into several classes based on aural and visual characteristics. This study verifies the classification system determined in previous studies, with the exception of class 8, and supports the division of class 1 into subclasses 1a and 1b. Class 1 appeared to be critical during sexual contexts and all highly social contexts, regardless of age and sex class. Although highly recognizable, its parameters exhibited much variation among social contexts; therefore class 1 may communicate graded emotional states in short-range interactions. Other classes of sounds may be utilized for long-distance communication, as startle responses, or "precursors" to the adult repertoire. Frequency-related parameters of all sound classes showed variation among social contexts, but duration demonstrated very little variation. Calf-containing contexts exhibited greatest and most varied frequencies; this is to be expected if gray whale's sound mechanism is related to body and tracheal length. Variation also may indicate that physical maturity or learning play a role in the repertoire development. The lowest and least varied frequencies were observed in adult contexts. Sound production rates also varied by social context. Active adults produced sounds at high rates during short intervals; mixed/unknown contexts were often silent. Calf-containing contexts produced sounds at intermediate rates and were never silent. The correlations demonstrated here between social context and use of sounds will allow for acoustics to be an indicator of group composition, seasonal movements, and social patterns, thus relieving dependency on difficult visual observation. Additionally, such correlations provide preliminary information for determining sound functions.