Contextual text mining

With the dramatic growth of text information, there is an increasing need for powerful text mining systems that can automatically discover useful knowledge from text. Text is generally associated with all kinds of contextual information. Those contexts can be explicit, such as the time and the location where a blog article is written, and the author(s) of a biomedical publication, or implicit, such as the positive or negative sentiment that an author had when she wrote a product review; there may also be complex context such as the social network of the authors. Many applications require analysis of topic patterns over different contexts. For instance, analysis of search logs in the context of the user can reveal how we can improve the quality of a search engine by optimizing the search results according to particular users; analysis of customer reviews in the context of positive and negative sentiments can help the user summarize public opinions about a product; analysis of blogs or scientific publications in the context of a social network can facilitate discovery of more meaningful topical communities. Since context information significantly affects the choices of topics and language made by authors, in general, it is very important to incorporate it into analyzing and mining text data. In general, modeling the context in text, discovering contextual patterns of language units and topics from text, a general task which we refer to as Contextual Text Mining, has widespread applications in text mining. In this thesis, we provide a novel and systematic study of contextual text mining, which is a new paradigm of text mining treating context information as the ``first-class citizen.'' We formally define the problem of contextual text mining and its basic tasks, and propose a general framework for contextual text mining based on generative modeling of text. This conceptual framework provides general guidance on text mining problems with context information and can be instantiated into many real tasks, including the general problem of contextual topic analysis. We formally present a functional framework for contextual topic analysis, with a general contextual topic model and its various versions, which can effectively solve the text mining problems in a lot of real world applications. We further introduce general components of contextual topic analysis, by adding priors to contextual topic models to incorporate prior knowledge, regularizing contextual topic models with dependency structure of context, and postprocessing contextual patterns to extract refined patterns. The refinements on the general contextual topic model naturally lead to a variety of probabilistic models which incorporate different types of context and various assumptions and constraints. These special versions of the contextual topic model are proved effective in a variety of real applications involving topics and explicit contexts, implicit contexts, and complex contexts. We then introduce a postprocessing procedure for contextual patterns, by generating meaningful labels for multinomial context models. This method provides a general way to interpret text mining results for real users. By applying contextual text mining in the ``context'' of other text information management tasks, including ad hoc text retrieval and web search, we further prove the effectiveness of contextual text mining techniques in a quantitative way with large scale datasets. The framework of contextual text mining not only unifies many explorations of text analysis with context information, but also opens up many new possibilities for future research directions in text mining.

The effect of maternal employment on adolescents' transition to young adulthood

The purpose of this study was to examine relationships between multiple characteristics of maternal employment, parenting practices, and adolescents’ transition outcomes to young adulthood. The research addressed four main research questions. First, are the characteristics of maternal work (i.e., hours worked, multiple jobs held, work schedules, earnings, and occupation) related to adolescents’ enrollment in post-secondary education, employment, or involvement in neither of these types of activities as young adults? Second, are the work characteristics related to parental involvement and monitoring, and are the parenting practices related to adolescents’ transition outcomes? Third, do parental involvement and monitoring mediate any relationships between the characteristics of maternal employment and adolescents’ transition outcomes? Finally, do any associations between characteristics of maternal employment and parenting practices and adolescents’ transition outcomes vary by poverty status, race/ethnicity, or gender? To address these research questions, secondary data analysis was conducted, using data from the National Longitudinal Survey of Youth (NLSY) from 1998 through 2004. The study sample consisted of 849 youths who were 15 through 17 years of age in either 1998 or 2000, and were 19 through 21 years of age when their transition outcomes in young adulthood were measured four years later. Multinomial logistic and ordinary least squares regression models were estimated to answer the research questions. Study findings indicated that of the maternal work characteristics, mothers’ multiple jobs held, occupation, and work schedule were significantly related to the youths’ transition outcomes. When mothers held multiple jobs for 1 to 25 weeks per year, and when mothers held jobs involving lower levels of occupational complexity, their youths were more likely to experience employment rather than post-secondary education. Adolescents whose mothers worked a standard work schedule were less likely to experience other types of transitions than post-secondary education. With regard to the effects of maternal employment on parenting practices, none of the maternal work variables were related to parental involvement, and only one variable, mothers working less than 40 hours per week, was negatively related to parental monitoring. In addition, when parents were more involved with their youths’ education, the youths were less likely to transition into employment and other types of transitions rather than post-secondary education. The parenting practices did not mediate the relation between the significant work variables (holding multiple jobs, work schedule, and occupation) and youths’ transition outcomes. Finally, none of the interactions between maternal work characteristics and poverty status, race/ethnicity, and gender met the criteria for determining significance; but in a series of sub-group analyses, some differences according to poverty status and gender were found. Despite the lack of mediation and moderation, the findings of this study have important implications for social policy and social work intervention. Based on the findings, suggestions are made in these areas to improve working mothers’ lives and their adolescents’ development and successful transition to adulthood. Finally, directions for future research are discussed.

IVIS: Search and visualization on heterogeneous information networks

We build a system to support search and visualization on heterogeneous information networks. We first build our system on a specialized heterogeneous information network: DBLP. The system aims to facilitate people, especially computer science researchers, toward a better understanding and user experience about academic information networks. Then we extend our system to the Web. Our results are much more intuitive and knowledgeable than the simple top-k blue links from traditional search engines, and bring more meaningful structural results with correlated entities. We also investigate the ranking algorithm, and we show that the personalized PageRank and proposed Hetero-personalized PageRank outperform the TF-IDF ranking or mixture of TF-IDF and authority ranking. Our work opens several directions for future research.

Sexuality in the media and emotional well-being among lesbian, gay, & bisexual adolescents

LGB teens’ feelings, desires, and physical attractions run contrary to the heteronormative standards of American society. As such, LGB youth often experience feelings of sadness and dejection that can lead to depression and suicidal tendencies (Russell & Joyner, 2001). Evaluating the factors that could possibly influence the emotional well-being of LGB youth would be an important undertaking given the hindrances LGB adolescents face during sexual socialization. The purpose of this dissertation was to study the portrayal of sexuality in media popular with LGB adolescents and to assess the relationship between media exposure and emotional well-being among LGB teens. In particular, this dissertation distinguished between mainstream media and gay- and lesbian-oriented (GLO) media. GLO media were defined as any media outlet specifically designed, produced, and marketed for gay and lesbian audiences. Two studies were conducted to serve as the initial investigation in a program of research that will be designed to better understand the role of media in the lives of LGB individuals. The first study of this dissertation was a content analysis of the television programs, films, songs, and magazines most popular with LGB teens as determined by self-reports of media consumption in a survey of media use. A total of 96 media vehicles composed the content analysis sample, including 48 television programs, 22 films, 25 musical artists, and 6 magazines. Using a coding scheme that was adapted from previous media sex research, Study 1 measured the frequency of sexual instances as well as the type, nature, and source characteristics for each sexual instance. Results of the content analysis suggest that heterosexuality reigns supreme in mainstream media. When LGB sexuality is depicted in mainstream media, it is often sanitized. LGB sexual talk is rarely sexual; rather it is primarily about the social or cultural components of being lesbian, gay, or bisexual. LGB sexual behavior is also rare in mainstream media, which tend to depict LGB individuals as non-sexually as possible. LGB sexuality in mainstream media exists, but is more about proclaiming LGB identity than actually living it. GLO media depicted LGB sexuality more frequently than mainstream media did. GLO media often depict LGB sexuality in a more realistic manner. LGB sexual talk is about LGB identity, as well as the relational and sexual aspects of being a sexual minority. LGB sexual behavior is commonplace in GLO media, depicting LGB individuals as sexual beings. LGB sexuality in GLO media is prevalent and relatively authentic. The second study was a survey that assessed the relationship between media exposure (both mainstream media and GLO media) and LGB teens’ emotional well-being, considering self-discrepancy as an important mediating variable in that relationship. Study 2 also considered age, sex, and sexual identity commitment as possible moderating variables in the relationship between media exposure and emotional well-being. In Study 2, emotional well-being was defined as lower levels of dejection-related emotions. LGB adolescents (N = 573) completed a questionnaire that was used to investigate the relationships between media exposure and emotional well-being. Results of the survey indicated that mainstream media exposure was not significantly associated with dejection-related emotions. In contrast, GLO media exposure was negatively related to feelings of dejection even when controlling for age, sex, race, perceived social support, school climate, religiosity, geographical location, sexuality of peers, and motivation for viewing LGB inclusive media content. Neither age nor sex moderated the relationships between media exposure variables and dejection, but sexual identity commitment did act as a moderator in the relationship between GLO media exposure and dejection. The negative relationship between GLO media exposure and dejection was stronger for participants lower in sexual identity commitment than for participants higher in sexual identity commitment. In addition, the magnitude of discrepancies between the actual self and the ideal self mediated the relationship between GLO media exposure and dejection for LGB adolescents low in sexual identity commitment. However, self-discrepancy did not mediate the relationship between GLO media exposure and dejection for LGB teens highly committed to their sexual identities. Results of both the content analysis and the survey are discussed in terms of implications for theory and method. Practical implications of this dissertation’s findings are also discussed, as well as directions for future research.