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過去總認為市場是有效率的，投資人是理性的，但近年來，行為財務學的興起，開始證明投資人經常做出不理性的行為，導致投資市場只有少數人為贏家，能長期獲得超額報酬。散戶的投資行為也是學術上時常探討的，而在過去幾年，國外開始有學者利用社群網站twitter，並用情緒辨識軟體將發文者的文章做情緒的歸類，來看能不能提升對大盤或個股的預測能力。結論是其中幾類情緒的確能提升預測大盤或個股的機率。而在台灣，比較有名的股票社群為PTT的股票板，該板通常會同時有1000人以上在線上。本文做了兩項研究，其一為藉由本週看多及看空文章的總數來看是否能預測未來幾週的大盤報酬，其二為藉由個股看多或看空文章的回文數，來看是否看多或看空文章的回文數愈多，是否能預測個股未來幾天的報酬，而以上兩項的結果，即使有些部分在統計上為顯著，但並沒有一致性，舉例來說，有些個股可能在第三天顯著，並與回文數呈負相關，但另一些個股可能在第5天顯著，並與回文數呈正相關，因此並無法得到一致性，很難有合理的解釋，因此可說明，PTT裡的發文及回文對整個投資市場來說，並無資訊內涵，並無法預測股市的報酬。 / The efficient market was popular before and most of the investors are seen as rationality. However, behavioral finance emerged in recent years. This theory tells us investors usually invest irrationally that there are only a few people in the market are winner in the long run. Retail investors’ behaviors are usually discussed in theses in recent years. In foreign country, there were some people studying the social network- twitter and use some software to judge the different emotions in an article in twitter. Finally, they found some types of emotions could predict the movement of stock prices or stock index like Dow Jones. In Taiwan, the stock section in PTT is famous. Many people express their opinions in stock section of PTT. In this paper, author use the bullish or bearish article to forecast the stock index a few weeks later and use the number of responses of an article for a specific stock to predict the return of the stock a few days later. The results are that some of the responses of stocks can predict stocks returns five days later and there are negative relation between the numbers of responses and the returns. However, other responses of stocks can predict stocks returns three days later and there are positive relation between the numbers of responses and the returns. The author can’t find the consistent results. There are more than1000 people stay in the stock section of PTT at the same time, but these people are only a small group in the stock market. Consequently, we can use PTT to predict the stock market.

The main objective of this dissertation is to develop the second generation of Distributed Digital Radio (DDR) technology. A DDR II modem provides an integrated voice/data service platform, higher data rates and better throughput performance as compared to a DDR I modem. In order to improve the physical layer performance of DDR modems an analytical framework is first developed to model the Bit Error Rate (BER) performance of Orthogonal Frequency Division Multiplexing over Frequency Modulation (OFDM/FM) systems. The use of OFDM provides a spectrally efficient method of transmitting data over LMR channels. However, the high Peak-to-Average (PAR) of OFDM signals results in either a low Signal-to-Noise Ratio (SNR) at FM receiver or a high non-linear distortion of baseband signal in the FM transmitter. This dissertation presents an analytical framework to highlight the impact of high PAR of OFDM signal on OFDM/FM systems. A novel technique for reduction of PAR of OFDM called Linear Scaling Technique (LST) is developed. The use of LST mitigates the signal distortion occurring in OFDM over FM systems. Another important factor which affects the throughput of LMR networks is the Push-to-Talk (PTT) delay. A PTT delay refers to the delay between the instant when a PTT switch on a conventional LMR radio is keyed/unkeyed and a response is observed at the radio output. It can be separated into a Receive-To-Transmit Switch Interval (RTSI) or a Transmit-To-Receive Switch Interval (TRSI). This dissertation presents the typical RTSI delay values, distributions and their impact on throughput performance of LMR networks. An analytical model is developed to highlight the asymmetric throughput problem and the unintentional denial of service (UDOS) occurring in heterogeneous LMR networks consisting of radios with different PTT delay profiles. This information will be useful in performance and capacity planning of LMR networks in future.

When adolescent girls growe up in the adolescence, facing physiological and psychological changes, they dress as a means to create the image of the body and to build their own social image ¢w how to be the right young girl in other¡¦s eyes. But there is no system to teach them how to change and self-shaping. When they are confronted with social demands and the capitalist or patriarchal shock, how to adjust their behavior. Online shopping has become a major shopping channel of many female students, female graduate students or the young female office workers. Today, using online shopping to purchase dress is also an important leisure entertainment to many adolescent girls. The e-shopping of PTT has become the gathering place of adolescent girls. Not only as an online shopping related information exchange field, but also become an important field of adolescent girls grow up group with emotional exchange.Shopping content and aesthetic criteria will be prevailed by e-shopping collective view. After the shopping experience, they expect supports of e-shopping. In addition to mother, sisters or classmates, colleagues, e-shopping has become an important reference, and some even replaced. The thourghts of adolescent girls are different to adult women and adolescent boyes. However, thinking and growth experience of adolescent girls have not been taken seriously, or limited to stereotype. In this study, the text of the form of direct contact with young girls in the e-shopping which comes from the real behavior are usd to understand the culture and values of adolescent girls between groups in online shopping. Through this e-shopping tunnel, the adolescent girls like through the rite of passage ceremony, into a mature woman.

The Internet is a common technology nowadays in our daily life. More and more people think it will soon replace traditional mass media and become the new age public forum. However, the cyberspace is not as open, free, and democratic as we may imagine. Actually more and more regulations and rules are imposed on it. But deviating behaviors such as conflicts, crimes, and violence did not decrease with all the regulations and rules. And the hierarchy of power and class did not disappear from the cyberspace as the internet utopians described. The researcher investigated one of the biggest and most popular virtual community in Taiwan, Gassiping Board in PTT Bulletin Board System, in particular regulation and power aspects, and tried to find out what is behind the regulations and how the collective behaviors of the users collide with the power of the administrators and the order of the board. Do they reflect any social value or internet culture? And what is the connection with the real world? With the idea of regulation in Lawrence Lessig¡¦s book Code v2 and the concept of cyberpower, the researcher analysed the important changes and conflicts occurred on Gassiping Board. Gassiping Board can be seen as a free speech market by Lessig¡¦s concept, and the rules serving as laws, which give power to the administrators, along with the internet norms, regulate the behaviour of the users. By the code, the administrators can execute the rules. However, the common users have their own power given by the design of the code to rival the administrators, and they can even change the rules, the norms, and the free speech market of Gassiping Board. Also, some changing effects come from outside the virtual community, namely from the real world. Although the administrators have superior power of technology, most of the time they are low in authority. It is hard for them to regulate all the users under the anti-control culture in the cyberspace. The users of Gassiping Board will gather all their powers when it is necessary, and will even destroy the order and overthrow the power of the administrators. However, this phenomenon indicates self-centredness and lack of respect to others, no matter if it is led by the common users or the administrators. Even though the internet is a modern technology product, in practice modern values such as the quality of democracy, law and order can not work with the internet users in making the virtual community a public sphere with both freedom and order.

The standards of beauty always change in every generation in Taiwan, but there is only one standard still has strong impact on people, that is:¡¨ having white complexion¡¨. People say: ¡§A white complexion is powerful enough to hide seven faults.¡¨ The reason of ¡§whitening¡¨ is important because of the different powers which compete with each other to decide the meaning behind the discourse of ¡§whitening¡¨. The concept of ¡§Whitening¡¨ is from the promotion of beauty industry. What¡¦s more, this concept also made a strong impact through the media on people who live in Taiwan. Thus, to understand how the media delivery the ¡§whitening¡¨ concept is very important, especially through the most important media--- Internet in this generation. The main purpose of this research is to find out the process of developing the discourse of ¡§whitening¡¨ within the on-line Beauty Salon community and the context behind the discourse in Taiwan. Another purpose is to seek out the minority discourse which seldom appear within the mass media and also provide the ability of reflectivity thinking. The main structure of this research base on the critical concept of ¡§Knowledge/ Power¡¨ from the post-modern scholars: Gramsci, Foucault and the post-colonialism scholar---Said to discuss how the ¡§whitening¡¨ discourse is developed by the ¡§center¡¨(ex. doctor, expert and business ) and ¡§margin¡¨(ex.net pal)within the on-line beauty community. This research choose qualitative research method to do the context analysis in the most popular on-line community which is also the biggest BBS in Taiwan---¡§PTT ¡¨ and choose ¡§Beauty Salon¡¨ community within PTT as the research field. The results show that the ¡§Whitening ¡¨ discourse is a knowledge system within ¡§Beauty Salon¡¨ community and developed by the hierarchy relationship form doctors, skin-care experts, cosmetic businesses and cosmetic sales. What¡¦s more, the role of ¡§black skin¡¨ is ¡§the other¡¨ and has the inferiority within this knowledge system of whitening discourse. And the voice of supporting black skin also disappeared within Beauty Salon community. To compare with Beauty Salon community, there was another temporary skin-care on-line discussion bard founded by YAHOO in March 2008. And it has less limit and more open to express their opinions. This research found that there is the voice of supporting black skin appearing within this field and also using the strategy of different mimicry to ¡§write back¡¨ the discourse developed by majority. This research found that if there are only few powers to develop the discourse, the discourse will become one-dimension and hardly to see the different other opinion against the mainstream or the ¡§center¡¨ opinion. This also tells us that the limit of structure from the oligopoly powers in the Internet will expropriate people¡¦s chance and freedom to choose and contact the different voices, and this situation is worthy to reflect.

Although technology is well developed, personal data is well spread in internet ,too. We can see a lot of privacy invasion in PTT. People can find a lot of data about someone from his name or movie. People are afraid of being caught in internet. But why some people support this kind of privacy invasion but some don¡¦t. What is the main factor? This study uses description and different kind of event to observe if description can affect people¡¦s decision toward privacy invasion. We separate description into violate and non-violate, and we use two stage survey to observe when people face different kind of description, is there any different between violate and non-violate description toward privacy decision making. In the end, we find how sex, description, and event affect privacy decision making, and we bring up a suggestion of privacy situational desion and the main factor toward privacy decision making.

Reproduction de : Thèse de doctorat : Science politique : Lyon 2 : 2003. / Titre provenant de l'écran-titre. Bibliogr.

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With the advances in technology and popularization of the Internet, the interaction of human beings in real society has extended to the Internet forum. Due to the low barrier for entering the Internet, people can always speak their mind freely and make comments on whatever they want to. Behind a world that seems to have freedom and equality of speech, the expression of opinions is being tested by standards of different cultures and living backgrounds. Using Gossiping¢wthe most popular and interactive board on PTT¢w as the source data, this study identifies the spiral of silence between the mainstream opinions and non-mainstream opinions. Where the spiral of silence occurred, the study also examines the force which affected the spiral based on the theories of stigma and analyze its accompanying meanings. With different positions, people resulted in different critical standards and stigma phenomenon. When facing stigma, people should realize the causes of things from the social and cultural dimensions, and rethink the positive meanings that stigma brings to us instead of being afraid of it.