本論文旨在探討YouTube上的博客怎樣演繹他們線上的身份。本文重點探討三個在視頻上用語言表達的方法，分別是說話、字幕和註解。YouTube是一個網上流行的視頻分享網站，但也可以視為進行社交的一個平台。是次研究採用三個語言學的層面探討問題，分別是言語行為、觀點和反諷。在多媒體研究的層面下，言語行為在研究中被重新定義為溝通行為。本研究旨在了解博客如何用多媒體的溝通表達方法表達言語行為、觀點和反諷，以至如何演繹他們線上的身份。 / 是次研究探討六個常博客，結合了定量和質量的分析方法。視頻在語言表達方法的框架下被輯錄，然後用兩個層面去分析。本研究首先詳細探討每一個表達方法有什麼不同的用處，然後在探討這些方法結合後怎樣表達語言。 / 本研究採用社會學的方法，目的在探討先前題過的方法怎樣表達出博客的身份，重點在博客如何以反諷表達。是次研究結果亦指出博客如何學會在YouTube上講和寫，以達到他們想有更多影片觀看者的動力。 / 本論文表現出一個傳統的言語行為理論怎樣在線上多媒體的研究上發揮作用。言語行為能被重新定義為多個小事件的結合。研究亦發現了新的言語行為種類，而這些種類是多媒體溝通才能遇見得到的。本研究解釋了反諷如何在線上多媒體進行表現和內涵的語言是並存的。本研究亦討論了博客線上和線下的身份如何取得平衡。 / 本論文提出了本研究採用的方法與傳統研究的方法有什麼抵觸，尤其是在資料收集方法和研究倫理的層面上。本論文提出機密度和匿名度如何在線上研究收到對待。 / This thesis is an investigation into the identity performance of YouTube vloggers (videobloggers), with emphasis on how that is achieved linguistically by three modes of communication available in a video: speech, subtitle, and annotation. YouTube is a popular video-sharing site that is also seen as a platform for social networking. The study looks into three aspects of linguistic analysis: speech act analysis, stancetaking, and verbal irony. Speech acts in this study are redefined as communicative acts to suit the multimodal nature of YouTube vlogs. This study aims to understand vloggers’ identity performance by investigating the use of communicative modes to perform communicative acts, stances, and irony. / Six vloggers participated in the study, which adopted a mixed method approach to data collection and analysis, alchemizing quantitative counting analysis with qualitative interview methods. Vlogs from the informants were transcribed with respect to the three modes of communication of interest, and analyzed in two ways. First, the modes were analyzed separately, revealing how vloggers use these modes differently. Next, the modes were investigated as a whole, looking into the essence of multimodal communication: how cross-modal interactions (mode-mixing and mode-switching) are performed. / A socialistic approach to discourse was adopted to investigate how the aforementioned performance of communicative acts informs vloggers’ identity performance. More specifically, this study looked at how irony is realized by communicative acts and alternations of stances, and how the performance of irony is related to the vloggers’ online identity performance. Findings also revealed vloggers’ learning of how to speak and write in order to become popular and attract more viewers, which is one of their motivations of vlogging. / This thesis demonstrates that the traditional linguistic model of speech acts can be adapted to the context of online multimodal communication with adjustments in definition: by seeing acts as a combination of microevents which interact to make meaning. The study also reports on newly identified categories of communicative acts made possible by multimodal discourse. The investigation reveals how irony is realized in multimodal communication, in which the surface and intended meaning are both present. The study discusses how these practices inform the performance of vloggers’ online identity, and how online and offline identities are maintained in balance. / The methods adopted in the study raise questions of how traditional conducts of research should be understood in the context of online research, particularly in the realm of data collection methods and research ethics. This thesis includes a thorough discussion of how confidentiality and anonymity are treated in this context. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Lien, Feng Pierre. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 140-146). / Abstracts also in Chinese. / Abstract (English) --- p.ii / Abstract (Chinese) --- p.iv / Acknowledgements --- p.vi / Table of Contents --- p.viii / List of Figures and Tables --- p.xii / Transcription Conventions --- p.xv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1. --- Overview --- p.1 / Chapter 1.2. --- The Advent of Web 2.0, YouTube, and Social Networking: An Auto-ethnographic Account --- p.1 / Chapter 1.3. --- YouTube: An Overview --- p.4 / Chapter 1.3.1. --- The Mechanics of YouTube --- p.5 / Chapter 1.3.2. --- From an Epistemic to an Affective Site: Social Networking on YouTube --- p.9 / Chapter 1.3.3. --- Identity Construction on YouTube --- p.12 / Chapter 1.4. --- From Experience to Theory: Perspectives Taken in this Study --- p.14 / Chapter 1.5. --- Research Aims and Research Questions --- p.16 / Chapter 1.6. --- Organization of the Thesis --- p.17 / Chapter Chapter 2 --- Literature Review --- p.19 / Chapter 2.1. --- Introduction --- p.19 / Chapter 2.2. --- Orality and Literacy --- p.20 / Chapter 2.3. --- Computer-Mediated Communication (CMC) --- p.22 / Chapter 2.3.1. --- Past Studies of CMC and Computer-Mediated Discourse (CMD) --- p.23 / Chapter 2.3.2. --- Cyberdiscursivity: When Orality and Literacy are not enough --- p.26 / Chapter 2.3.3. --- YouTube as a CMCMD --- p.28 / Chapter 2.4. --- Linguistic Discourse and Multimodality --- p.30 / Chapter 2.4.1. --- Cross-modal interaction: Mode-switching and Mode-mixing --- p.32 / Chapter 2.5. --- Language and Identity in CMC --- p.34 / Chapter 2.5.1. --- Identity Performance in CMC --- p.35 / Chapter 2.5.2. --- Multimodal Identities in CMC --- p.39 / Chapter 2.5.3. --- Identity and Stancetaking in CMD --- p.40 / Chapter 2.6. --- Language as Performatives: Speech Acts and Communicative Acts --- p.42 / Chapter 2.6.1. --- Speech Acts in CMC: Expanding the Framework --- p.45 / Chapter 2.6.2. --- Identity and Playfulness in CMC --- p.46 / Chapter 2.6.2.1. --- Humor and Irony in CMC --- p.47 / Chapter 2.6.2.2. --- Irony and Communicative Acts --- p.50 / Chapter 2.7. --- Summary --- p.51 / Chapter Chapter 3 --- Methodology --- p.53 / Chapter 3.1. --- Introduction --- p.53 / Chapter 3.2. --- Reprise of Research Aims and Research Questions --- p.53 / Chapter 3.3. --- Multiple-Case Study --- p.54 / Chapter 3.3.1. --- Informants --- p.55 / Chapter 3.4. --- Data Collection --- p.57 / Chapter 3.4.1. --- Vlog linguistic transcriptions --- p.57 / Chapter 3.4.2. --- Interview Data --- p.61 / Chapter 3.5. --- Procedure --- p.63 / Chapter 3.6. --- Pilot Study with Lindsey --- p.65 / Chapter 3.7. --- Challenges and Insights in Online Methodological Design --- p.68 / Chapter 3.7.1. --- Online Interviews --- p.68 / Chapter 3.7.2. --- Ethics of Online Research --- p.70 / Chapter 3.8. --- Summary --- p.73 / Chapter Chapter 4 --- Communicative Acts and Irony on Vlogs --- p.75 / Chapter 4.1. --- Introduction --- p.75 / Chapter 4.2. --- Overview of Vloggers and Their Vlogs --- p.75 / Chapter 4.3. --- Communicative Act Analyses --- p.76 / Chapter 4.3.1. --- Intra-semiotic Analysis --- p.77 / Chapter 4.3.2. --- Inter-semiotic Analysis --- p.82 / Chapter 4.5. --- Summary --- p.91 / Chapter Chapter 5 --- The Case of Lindsey --- p.93 / Chapter 5.1. --- Introduction --- p.93 / Chapter 5.2. --- Profile of Lindsey --- p.93 / Chapter 5.3. --- Learning to Write on Vlogs: Establishing Identity through Idioms of Practice . --- p.95 / Chapter 5.4. --- Subtitling a Vlog: Stancetaking, Contradiction, and Irony --- p.101 / Chapter 5.5. --- Identity on and off YouTube --- p.110 / Chapter 5.6. --- Summary --- p.113 / Chapter Chapter 6 --- The Case of Ron --- p.114 / Chapter 6.1. --- Introduction --- p.114 / Chapter 6.2. --- Profiling Ron --- p.114 / Chapter 6.3. --- Blending in: Becoming a Part of the YouTube Community --- p.115 / Chapter 6.4. --- Question of the Week: Expansion of Idioms of Practice and Playfulness --- p.117 / Chapter 6.5. --- Ron’s Identity Performance --- p.122 / Chapter 6.5.1. --- Ron’s Writer and Speaker Identities --- p.122 / Chapter 6.5.2. --- ‘I don’t need to be real’: Online and Offline Identities --- p.126 / Chapter 6.6. --- Summary --- p.128 / Chapter Chapter 7 --- Conclusion --- p.130 / Chapter 7.1. --- Introduction --- p.130 / Chapter 7.2. --- Findings to Research Questions --- p.130 / Chapter 7.2.1. --- Findings to Research Question Set 1 --- p.131 / Chapter 7.2.2. --- Findings to Research Question Set 2 --- p.132 / Chapter 7.2.3. --- Other findings --- p.134 / Chapter 7.3. --- Implications of the Study --- p.135 / Chapter 7.4. --- Limitations and Directions for Future Research --- p.138

Today's popular over-the-top (OTT) video streaming services such as YouTube, Netflix and Hulu deliver video contents to viewers using adaptive bitrate (ABR) technologies. In ABR streaming, a video player running on a viewer's device adaptively changes bitrates to match given network conditions. However, providing reliable streaming is challenging. First, an ABR player may select an inappropriate bitrate during playback due to the lack of direct knowledge of access networks, frequent user mobility and rapidly changing channel conditions. Second, OTT content is delivered to viewers without any cooperation with Internet service providers (ISPs). Last, there are no appropriate tools that evaluate the performance of ABR streaming along with video quality of experience (QoE). This thesis describes how to improve the video QoE of OTT video streaming services using ABR technologies. Our analysis starts from understanding ABR heuristics. How does ABR streaming work? What factors does an ABR player consider when switching bitrates during a download? Then, we propose our solutions to improve existing ABR streaming from the perspective of network operators who deliver video content through their networks and video service providers who build ABR players running on viewers' devices. From the network operators' point of view, we propose to find a better video content server based on round trip times (RTTs) between an edge node of a wireless network and available video content servers when a viewer requests a video. The edge node can be an Internet Service Provider (ISP) router in a Wi-Fi network and a packet data network gateway (P-GW) in a 4G network. During the experiments, our solution showed better TCP performance (e.g., higher TCP throughput during playback) 146 times out of 200 experiments (73%) over Wi-Fi networks and 162 times out of 200 experiments (81%) over 3G networks. In addition, we claim that the wireless edge nodes can assist an ABR video player in selecting the best available bitrate by controlling the available bandwidth in the radio access network between a base station and a viewer's device. In our Wi-Fi testbed, the proposed solution saved up to 21% of radio bandwidth on mobile devices and enhanced the viewing experience by reducing rebufferings during playback. Last, we assert that software-defined networking (SDN) can improve video QoE by dynamically controlling routing paths of video streaming flows based on the provisioned networking information collected from SDN-enabled networking devices. Using an off-the-shelf SDN platform, we showed that our proposed solution can reduce rebufferings by 50% and provide higher bitrates during a download. From the perspective of video service providers, higher video QoE can be achieved by improving ABR heuristics implemented in an ABR player. To support this idea, we investigated the role of playout buffer size in ABR streaming and its impact on video QoE. Through our video QoE survey, we proved that a large buffer does not always outperform a small buffer, especially under rapidly varying network conditions. Based on this finding, we suggest to dynamically change the maximum buffer size in an ABR player depending on the current capacity of its playout buffer for improving the QoE of viewers. During the experiments, our proposed solution improved the viewing experience by offering 15% higher average played bitrate, 70% fewer bitrate changes and 50% shorter rebuffering duration. Our experimental results show that even small changes of ABR heuristics and new features of network systems can greatly affect video QoE. However, it is still difficult for video service providers or network operators to evaluate new ABR heuristics or network system changes due to lack of accurate QoE monitoring systems. In order to solve this issue, we have developed YouSlow ("YouTube Too Slow!? - YouSlow") as a new approach to monitoring video QoE for the analysis of ABR performance. The lightweight web browser plug-in and mobile application are designed to monitor various playback events (e.g., rebuffering duration and frequency of bitrate changes) directly from within ABR video players and calculate statistics along with video QoE. Using YouSlow, we investigate the impact of the above playback events on video abandonment: about 10% of viewers abandoned the YouTube videos when the pre-roll ads lasted for 15 seconds. Even increasing the bitrate can annoy viewers; they prefer a high starting bitrate with no bitrate changes during playback. Our regression analysis shows that bitrate changes do not affect video abandonment significantly and the abandonment rate can be estimated accurately using the rebuffering ratio and the number of rebufferings. The thesis includes four main contributions. First, we investigate today's popular OTT video streaming services (e.g., YouTube and Netflix) that use ABR streaming technologies. Second, we propose to build QoS and QoE aware video streaming that can be implemented in existing wireless networks (e.g., Wi-Fi, 3G and 4G) and in SDN-enabled networks. Third, we propose to improve current ABR heuristics by dynamically changing the playout buffer size under varying network conditions. Last, we designed and implemented a new monitoring system for measuring video QoE.

Depression contributes to a host of health problems resulting in disability, pain, and death. An important aspect of preventing and reducing the harmful effects of depression is educating the public about this pervasive mental disorder, including the importance of early detection and effective treatment. During the past 20 years, many people have turned to the Internet in general and social media in particular to learn about health. Current research has examined YouTube coverage of some mental health topics, but no published research describing YouTube coverage of depression was identified. The purpose of this study was, therefore, to describe the most viewed YouTube about depression with respect to source, speaker, format, purpose, number of views, length, upload year, and content. A cross-sectional design was used to examine the 394 most viewed YouTube videos on depression. Collectively, these 394 videos were viewed 155,349,029 times. Three sources—consumers, internet-based video, and nongovernmental agencies—accounted for approximately 85% of the most frequently viewed videos and garnered 93% of the total views (n=144,506,467). Consumers uploaded almost half of all the most widely viewed videos (n=193, 48.98%), and these videos had the highest cumulative view count (74,391,500 views). Content mainly focused on signs and symptoms, which were covered in more than 75% of the videos (n=300, 76.14%), and promotion of healthful behaviors and protective factors, which was covered in 68.52% (n=270). Slightly more than one-half of the videos explicitly mentioned risk factors (n=200), and slightly less than one-half provided general information about depression (n=189). Between 20% and 35% of the videos included content related to suicide (23.10%), stigma (22.08%), psychotherapy (28.93%), medication (31.22%), and alternative therapies (30.96%). Content related to screening was only included in 9 of the most widely videos (2.28%). While good sleep hygiene was only mentioned in 28 videos (7.11%), collectively, these videos received over 16 million views. Another main finding was that governmental agencies have not produced videos that are among those most widely viewed. Given YouTube’s wide reach, they should, however, be using this media channel to help inform the public.

In 2016, over 11 million people misused prescription opioids and the economic costs were estimated to be over $500 billion. In the same year, opioids killed 42,000 people, which was more than any year on record. These data highlight the need to reduce the harm caused to individuals, families, communities, and the nation. One element of a more comprehensive national strategy is increasing awareness among citizens, physicians and policy makers. Given its widespread reach YouTube can be very helpful. There is a large literature on the opiate epidemic, but no published studies describing the sources or content of YouTube videos on the opiate epidemic were identified. This study was, therefore, intended to help fill this gap in current knowledge. YouTube was searched using two key terms, “opiate addiction” and “opioids.” The results were sorted by number of views, and the URL, title, and number of views were saved for videos with a minimum of 1,500 views. Videos were then screened for the inclusion and exclusion criteria. The remaining sample comprised 309 videos. Collectively, these 309 videos were viewed 44,693,887 times. The results revealed the sources that were most viewed and the nature of content that was and was not likely to be covered. The two main sources of videos were Internet Based and Television news/Entertainment. Compared with videos with health professions as the main speaker, those featuring consumers garnered almost 10 times as many cumulative views (30.35%versus 3.24%). Government organizations uploaded 11 videos (< 4%), collectively garnering 343,983 views (less than 1% of cumulative views). YouTube represents an important opportunity for health promotion and disease prevention regarding the opiate epidemic. However, improved understanding about ways to communicate accurate and useful information in ways that attract viewers is needed. Recommendations for research, policy and practice are presented relevant to how YouTube can help mitigate the harm caused by the opiate epidemic.

Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2018-08-08T11:27:31Z No. of bitstreams: 1 Manuella Vieira Reale.pdf: 52740448 bytes, checksum: 6fd6179e2cf5c8a252b6435fa1b358a0 (MD5) / Made available in DSpace on 2018-08-08T11:27:31Z (GMT). No. of bitstreams: 1 Manuella Vieira Reale.pdf: 52740448 bytes, checksum: 6fd6179e2cf5c8a252b6435fa1b358a0 (MD5) Previous issue date: 2018-06-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Pontifícia Universidade Católica de São Paulo - PUCSP / This research seeks to understand which are the different enunciative strategies and the regimes of meaning and interaction of scientific communication brazilian channels on online videos - especially on YouTube s platform - as a way to cultivate the taste for science. Therefore, we aim: investigate the constructed senses and ways of presence of scientific communication destinators in the selected digital environment; observe and question the scientific communication terminology; identify enunciation marks that indicate doings shaped by metadestinator YouTube; discuss what leads a certain statement to be credible; debate the scientific communication as an approximation between scientific field and common sense. lt is recognized the relevance of scientific field in contemporary society and the role of scientific communication in dissemination of complex science. Hypotheses to be tested are: YouTube enables multiplicate audiovisual productions about scientific knowledge; scientific communication channels make the taste for science an object of value in the approximation between scientific knowledge and common sense; interactions promoted in this platform provide feedback on the part of the destinee, revealing their simulacra. The object of study consists in channels with scientific content, whose posting is regular, recent and original. A mapping is accomplished of the productions by search and data survey, resulting in an overview of current brazilian productions whose division was made in four categories relating degree of audiovisual production and formal specialization in science. They are: Beginner, Professional Producer, Certificated Specialist and lnitiated. The corpus channels, chosen respectively from each category, are: Alimente o Cerebro, Manual do Mundo, Canal do Pirula and Nerdologia. The theoretical current of French semiotics of Algirdas J. Greimas and his followers, based on the generative course of meaning, will ground the analysis of enunciation in each syncretic text, as well as the meaning and interaction regimes according to Eric Landowski. Regarding the science notion, the main authors are Thomas Kuhn and Edgar Morin and, to discuss scientific communication definition, Wilson Bueno, Carlos Vogt and Bruce Lewestein. ln meaning and interaction regimes, it is possible to see how destinators use strategic narratives to impel the construction of meaning along the destinee in order to accentuate the taste for science as an object of value / A seguinte pesquisa busca compreender quais as diferentes estrategias enunciativas e os regimes de sentido e de interagao dos canais brasileiros de divulgagao cientffica em vfdeos online - especificamente na plataforma YouTube - como modo de cultivo do gosto pela ciencia. Para tanto, objetiva-se: investigar os sentidos construfdos e os modos de presenga dos destinadores de divulgagao cientffica no ambiente digital selecionado; observar e questionar a terminologia da divulgagao cientffica; identificar as marcas de enunciagao que indicam fazeres moldados pelo metadestinador YouTube; discutir o que leva certo enunciado a ser crfvel; debater a divulgagao da ciencia na aproximagao do campo cientffico com o senso comum. Reconhece-se a relevancia do campo do conhecimento cientffico na sociedade contemporanea e o papel da divulgagao cientffica na comunicagao da ciencia complexa. As hip6teses a serem testadas sao: o YouTube possibilita a multiplicagao de produg6es audiovisuais sobre o conhecimento cientffico; os canais de divulgagao cientffica fazem do gosto pela ciencia um objeto de valor na aproximagao entre conhecimento cientffico e senso comum; as interag6es promovidas nessa plataforma proporcionam uma retroalimentagao por parte do destinatario, desvelando seus simulacros. 0 objeto de estudo e composto por canais com conteudo de teor cientffico, cuja postagem dos vfdeos e regular, recente e original. Realiza-se um mapeamento das produg6es da plataforma por procura e levantamento de dados, resultando em um panorama das atuais produg6es brasileiras cuja divisao foi feita em quatro categorias relacionando o grau de produgao audiovisual e a especializagao formal em ciencia. Sao elas: lniciante, Produtor profissional, Especialista titulado e lniciado. 0s canais do corpus, elegidos respectivamente de cada categoria, sao: Alimente o Cerebro, Manual do Mundo, Canal do Pirula e Nerdologia. A corrente te6rica da semi6tica francesa de Algirdas J. Greimas e seus seguidores, a partir do percurso gerativo de sentido, fundamentara o exame da enunciagao de cada texto sincretico, assim como os regimes de sentido e de interagao segundo Eric Landowski. Para a nogao de ciencia, os principais autores sao Thomas Kuhn e Edgar Morin e, para debater a definigao de divulgagao cientffica, Wilson Bueno, Carlos Vogt e Bruce Lewestein. Em diferentes regimes de sentido e de interagao, verifica-se como os destinadores langam mao de narrativas estrategicas para impelir a construgao de sentido conjuntamente com o destinatario a fim de acentuar o gosto pela ciencia enquanto objeto de valor