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Full-Text Articles in Social and Behavioral Sciences

Anomaly Detection On Social Data, Hanbo Dai Jun 2013

Anomaly Detection On Social Data, Hanbo Dai

Dissertations and Theses Collection (Open Access)

The advent of online social media including Facebook, Twitter, Flickr and Youtube has drawn massive attention in recent years. These online platforms generate massive data capturing the behavior of multiple types of human actors as they interact with one another and with resources such as pictures, books and videos. Unfortunately, the openness of these platforms often leaves them highly susceptible to abuse by suspicious entities such as spammers. It therefore becomes increasingly important to automatically identify these suspicious entities and eliminate their threats. We call these suspicious entities anomalies in social data, as they often hold different agenda comparing to …


Fair Cost Sharing Auction Mechanisms In Last Mile Ridesharing, Duc Thien Nguyen Jan 2013

Fair Cost Sharing Auction Mechanisms In Last Mile Ridesharing, Duc Thien Nguyen

Dissertations and Theses Collection (Open Access)

With rapid growth of transportation demands in urban cities, one major challenge is to provide efficient and effective door-to-door service to passengers using the public transportation system. This is commonly known as the Last Mile problem. In this thesis, we consider a dynamic and demand responsive mechanism for Ridesharing on a non-dedicated commercial fleet (such as taxis). This problem is addressed as two sub-problems, the first of which is a special type of vehicle routing problems (VRP). The second sub-problem, which is more challenging, is to allocate the cost (i.e. total fare) fairly among passengers. We propose auction mechanisms where …


Three Essays On Large Panel Data Models With Cross-Sectional Dependence, Yonghui Zhang Jan 2013

Three Essays On Large Panel Data Models With Cross-Sectional Dependence, Yonghui Zhang

Dissertations and Theses Collection (Open Access)

My dissertation consists of three essays which contribute new theoretical results to large panel data models with cross-sectional dependence. These essays try to answer or partially answer some prominent questions such as how to detect the presence of cross-sectional dependence and how to capture the latent structure of cross-sectional dependence and estimate parameters efficiently by removing its effects. Chapter 2 introduces a nonparametric test for cross-sectional contemporaneous dependence in large dimensional panel data models based on the squared distance between the pair-wise joint density and the product of the marginals. The test can be applied to either raw observable data …


Impact Of Multimedia In Sina Weibo, Xun Zhao Jan 2013

Impact Of Multimedia In Sina Weibo, Xun Zhao

Dissertations and Theses Collection (Open Access)

Multimedia contents such as images and videos are widely used in social network sites nowadays. Sina Weibo, a Chinese microblogging service, is one of the first microblog platforms to incorporate multimedia content sharing features. This thesis provides statistical analysis on how multimedia contents are produced, consumed, and propagated in Sina Weibo. Based on 230 million tweets and 1.8 million user profiles in Sina Weibo, we study the impact of multimedia contents on the popularity of both users and tweets as well as tweet life span. In addition to consider the multimedia impact on popularity, we also compare the user influence …


Three Essays On Mutual Fund Ratings, Wee Seng Ng Jan 2013

Three Essays On Mutual Fund Ratings, Wee Seng Ng

Dissertations and Theses Collection (Open Access)

The incessant growth of the mutual fund industry has made the task of selecting mutual funds an increasingly challenging one. Unsophisticated investors turn to low-cost and readily available ratings to guide their investment decisions. Unsurprisingly, mutual fund ratings are hugely popular and influential. Anecdotal evidence and academic findings both suggest that investors gravitate towards top-rated funds. Rating is a double-edged sword. Although the use of rating simplifies the otherwise onerous job of evaluating mutual fund performance, it can lead to adverse consequences. Investors who invest only in top-rated funds are inadvertently assuming that good ratings indicate good future performance. However, …