<p>This dissertation considers the relationship between peer and individual student interaction. The central finding is that self reported friends play a crucial role in individual behaviors, a role that is more significant than other students in their school. Also, using the network of friendships within a school it is possible to construct new peer effect measures and account for endogenous peer group formation. It is however important to distinguish these peer measures from unobserved individual characteristics that may also influence behavior.</p><p>The first chapter examines the effect of potentially misidentifying the reference group on peer effect estimates. The differential impact of school, grade and friend level peer effects on student decisions to smoke and drink are calculated. Friendship nominations come from the Add Health dataset, where students can list up to 10 friends from the school. The bias due to endogenous peer group formation and simulteneity are considered using various instrumenting strategies. Peer effects are found to be large and significant at the friends level for both delinquency variables. It is possible to show that misidentifying the peer group can result in peer effect estimates that are understated by as much as 40\%.</p><p>The second chapter of the dissertation further examines the role of peer interactions, this time considering the effect of popularity on student academic achievement. Recent work has found a strong positive relationship between these variables. In this chapter I ascertain the robustness of these previous findings to controls for unobserved student heterogeneity using and instrumenting technique and a structural model. The results indicate that popularity influences academic achievement positively in the baseline model. However, instrumenting for popularity or including measures of unobserved student characteristics results in a large drop in the effect of popularity, and leads to a significantly negative coefficient in the majority of cases. Interestingly, popularity influences future earnings and attitudes positively, where this effect is robust to the inclusion of unobserved type. Policy simulations where students are redistributed based on race or income indicate that the predicted number of friendships and popularity fall but academic achievement increases. Since student popularity increases happiness and earnings, the overall effect of the redistribution policies have to be considered before implementation.</p> / Dissertation

The technology is changing fast in current business environment, today¡¦s success maybe will be gone by tomorrow. Therefore, the organization needs to keep learning and innovating to survive. To become a willing sharing and creation organization, the firm needs to gather all the knowledge in department, group and each employee. The key success of knowledge sharning is the employee¡¦s willingness of sharning knowledge. The knowledge is created through people¡¦s interation and the knowledge sharing is built on people¡¦s relation. The purpose of this rearch is to explor the employee¡¦s knowledge sharing willingness through social network approach. In the other hand, the psychological ownership could bring positive work attitude. Therefore the moderating effect of psychological ownership to social network and knowledge sharing willingness will be discussed as well. The target groups of this study are production or technology related departments of high technology companies. The samples are engineers, deputy engineers and supervisors. The total valid samples are 7 companies, 13 departments and 159 employees. Research method includes social network analysis software Ucinet and Hierarchical Regression Analysis. The result shows psychological ownership could raise the engineers¡¦ knowledge sharing willingness and moderate the relationship between in-degree centrality of advice network and knowledge sharing willingness. The findings are as follows: 1. Network degree centrality of internal advice network does not affect knowledge sharing willingness. 2. Psychological ownership positively and significantly affected knowledge sharing willingness. 3. Psychological ownership as the moderator positively and significantly affected the network degree centrality of internal advice network and knowledge sharing willingness partially.

This thesis explores reasons why a voter would vote for a ¡§independent¡¨candidate in a city council¡¦s election. Since respondents in a telephone survey are not able to give their thoughts and description of vote intention thoroughly. given few survey questions .I therefore chose in-depth interview conducted before the election day to explore the real thoughts of the voters. My in-depth interview respondents are selected by telephones surveys and were interviewed regarding four topics, including party identification, political views, candidates and social networks. I find that partisanship is not the main factor of voting for an independent candidate. Instead, the key is his or her ability to serve the voters. The second factor is the ability to execute the public welfare policies and the third is education background and experiences in the field of public service. Fourth social network has limited effects on voters who were born in the 70¡¦s and 80¡¦s. Moreover, I discovered that the effects of the party ideology on voting behavior might differ across levels of elections. In particular, Kaohsiung voters will take the cue of party ideology at the city mayor¡¦s election, while this may not apply to a city council¡¦s election.

Background: Tue Businessweek magazine proposed lists of attending doctors in medical centers and regional hospitals based on the recommendation of hospital presidents, directors and supervisors of medical societies, and surveyed doctors. The current study aims to investigate the criteria existing in Businessweek¡¦s selection and factors related to the nomination of Taiwan¡¦s best 100 doctors. Material and Method: Subjects are the 667 doctors nominated in Businessweek¡¦s ¡§100 Especially Recommended Doctors¡¨ and ¡§600 Doctor-Recommended Doctors,¡¨ published respectively on May 5th and October 3rd, 2008. Biographical data of the subjects is firstly reorganized according to such items as specialty, hospital, education, professional training, experience and current status; introduction to specialties on websites of the hospitals where the subjects serve is also taken into consideration during data reorganization. Secondly, additional social network variables, including special positions in such non-hospital and non-school institutions as societies, foundations and publishing companies, are implemented. Collected data is analyzed by means of descriptive statistics, chi-square test and logistic regression. Results: Out of the 667 doctors, the 131 ones especially recommended by Businessweek tend to either serve in northern Taiwan or have graduated from National Taiwan University. In terms of social network, ¡§directors¡¨ of a department/branch/center are 3.082 times more likely to be nominated among the 131 than those who do not have the title, while those with special positions in medical societies are 5.314 times more likely to be nominated than those without any special position. Conclusion: The physicians not only training in the medical profession, but also need to expand social network.

Dong Gang are the biggest fresh tuna market in Taiwan. This thesis deals with the social networks in Dong Gang tuna market and how they affect the tuna market in Dong Gang. This thesis finds that although Dong Gang tuna market has public auctions, the transactions and exchange of information are highly shaped by social networks, especially in the Bluefin Tuna season that starts in April and end in June. Actors use social networks to avoid risk, control prices and maintain the quality of purchase. On the other hand, the status of actors, which is highly influenced by the licenses from the state, also has significant impacts. There are two kinds of license in Dong Gang tuna market; one for domestic market and one for export. Actors with higher status buying fish firs. This research recognizes that the market is embedded in social structure of economic sociology, and explains the dual meaning of the market: entity and concept. It also points out how local social networks shape deal of market. On the other hand, the price of Japanese tuna market influences Dong Gang tuna market; in other words, the Dong Gang tuna market is part of global tuna market leading by Japan, and the state uses license to control. That is, the Dong Gang fish market consists of local social networks, but also connects with state and global tuna market.

With the popularity of the Internet and the growing trend of Web2.0, interaction and knowledge exchanges among the Internet users become active. Facebook, currently the world's most successful social networking website of Web2.0, functions as a social entertainer and further develops as a marketing business platform. In particular, many enterprises and organizations focus on operating the function of Fan Page for the purpose of marketing strategy. The research will be conducted from the users' viewpoints and the examples of consumption on Facebook and entertaining Fan Pages will be provided to investigate the specialties and functions of the website, causing the users to organize and participate in the Fan Pages, and the behaviorial motives and the gratification obtained from the process. Substantial and virtual random samplings are utilized in conducting the questionnaire survey. The result shows the obvious difference in the motives of the Fan Page participants based on various levels of education. It also verifies the critical influence of media characteristics on the participation of Fan Page. And, it helps us realize that users with different motives obtain different satisfactions through the participation of Fan Page. In the end, the research investigation can be considered as a basis of enterprise marketing strategies theoretically and practically.

Social network web sites become very popular nowadays. Users can establish connections with other users forming a social network, and quickly share information, photographs, and videos with friends. Malwares called social network worms can send text messages with malicious URLs by employing social engineering techniques. They are trying let users click malicious URL and infect users. Also, it can quickly attack others by infected user accounts in social network. By curiosity, most users click it without validation. This thesis proposes a malicious URL detection method used in Facebook wall, which used heuristic features with high classification property and machine learning algorithm, to predict the safety of URL messages. Experiments show that, the proposed approach can achieve about 96.3% of True Positive Rate, 95.4% of True Negative Rate, and 95.7% of Accuracy.

The purpose of this paper is to study underground Mark Six, which is among the most popular activities in Taiwan. Although it involves complicated financial transaction and lots of people, the deriving debt has no legal status according to principle ¡§the gamble debt is illegal¡¨ proscribed in Taiwanese civil law. This thesis focuses on how this system operates without the assurance of the legal system, which is widely believed as the foundation of modern property right. This Data were collected by in-depth interview and participant observation, including 23 interviewers in three main roles and other related actors, gamblers, brokers, bankers, and then, observing the transaction details of underground Mark Six in the illegal casino to analyze the issue specifically. This study identities three major mechanisms that maintain the operation of underground Mark Six: social Network, violence and risk Management. First, the definition of Social network is the relationship construction under the illegal Mark Six transaction. Trust and reputation, derived from the social network, protect transaction safety as a normative force. Next, the mechanism of violence is the transaction progress which judges in underworld way. Also, the mechanism of violence has the technique of evasion of law. Third, the mechanism of risk management is by different layers' actors to work on, and therefore, these actors cause the variation of transaction rule, method and restriction. In order to avoid debt quarrel, for instance, gamblers in lower layer usually decrease the risks by separating the creditor's right to different uplinks.For the brokers in the middle layer, they use a specific transaction record to insure the transaction execution. What's more is that the bankers in the top layer would control the signed Mark Six number for some specific number to prevent a horrible ¡§Hot Pack¡¨ result. I also find that recently Underground Mark Six is toward network technology, gathering with the traditional manual operation. These two executions so called ¡§Computer Operation¡¨ and ¡§Paper Operation.¡¨ Computer operation, moreover, is toward to be an institutionalization franchise, leading the Underground Mark Six to a technology operation, especially for account and managing risk.

The development of internet is creating intense competition in social network sites nowadays. How to conduct users¡¦ loyalty to social network sites gradually becomes an important issue to operate long-term social network sites. The study attempts to examine how consumers¡¦ utilitarian value, hedonic value and social value affect their loyalty. Furthermore, this study examines whether the relationship is mediated by gender difference. The model and relationship are tested and validated by using PLS and data collected from 200 people having facebook accounts in Taiwan. The results shows that loyalty is strongly affected by utilitarian value, hedonic value and social value. We also find that the difference of gender has positive influence on hedonic value and loyalty and negative influence on social value and loyalty. The implication for research and practice are also discussed.

Abstract The thinking of subverting the Internet world is ubiquitous. In Taiwan, a wave of ¡§Happy Farm¡¨ made FACEBOOK popularity soar. Community management of this site includes dynamic sharing, online chat, Club management, Fan zone, and many other online games. It also lets the application designers enrich the site content in an open way. ¡§The Facebook¡¨ operated from February 2004 to the present. Now review the Facebook site, and it¡¦s not difficult to find the design term constantly updates connotation philosophy to match up the various types of users. The study of the social networking sites shows that the ages are on the downward trend. For now, from the 13-year-old junior high school students to the general public are included. In Taiwan, ther e are 12,107,600 population using the Facebook.(101.7.5 Ministry of the Interior statistics). Taiwan¡¦s population accounts for about 23,261,747. It means half of Taiwan¡¦s population using the Facebook. The proportion is quite popular, which is an important reference for the study of nation also of information technology in Taiwan. The research focused on the junior high school students¡¦habits of using the Facebook. We also cited the junior high school teachers¡¦ observation and interviewed development applications industry to construct the overall architecture which can be used to observ how the habits influence the students¡¦ lives and know the changes brought about by the community website. The conclusion is to give parents , teachers, and the community one note about the junior highschool students¡¦ use of the community network. The results of the following four conclusions. 1. FACEBOOK is the website of the ¡§Interpersonal Community¡¨. 2. FACEBOOK advantage is high interaction, free, and diverse functions. 3.Woman users¡¦rate of response on website message is high than men¡¦s. 4. Higher grade students who use FACEBOOK have better interpersonal relations.