My dissertation aims to contribute to a more comprehensive understanding of how consumers make sense of online word-of-mouth. Each essay in my dissertation probes beyond the effect of rating valence and explores the role of textual content. In the first essay, I explore negativity bias among online consumers evaluating peer information about potential sellers. I propose that both the likelihood of negativity bias and resistance to change after a trust violation will depend on the domain of information discussed in a review. Three experiments showed that negativity bias is more prominent for information regarding sellers' integrity than information regarding their competence. These findings suggest that the universality of negativity bias in a seller review setting has been exaggerated. In the second essay, I examine the impact of emotional arousal on the perceived helpfulness of text reviews. I propose an inverse U-shaped relationship by which the arousal conveyed in a text review will be associated by readers with lower perceived helpfulness only beyond an optimal level, and that the detrimental effect of arousal is present for negative reviews even when objective review content is controlled for. To test these hypotheses, two studies were conducted in the context of Apple's mobile application market. In Study 1, I collected actual review data from Apple's App Store, coded those reviews for arousal using text analysis tools, and examined the non-linear relationship between arousal and review helpfulness. In Study 2, I experimentally manipulated the emotional arousal of reviews at moderate to high levels while holding objective content constant. Results were largely consistent with the hypotheses. This essay reveals the necessity of considering emotional arousal when evaluating review helpfulness, and the results carry important practical implications. In the third essay, I explore effects of the emotions embedded in a seller review on its perceived helpfulness to readers. I propose that over and above the well-known negativity bias, the impact of discrete emotions in a review will vary, and that one source of this variance is perceptions of reviewers' cognitive effort. I focus on the roles of two distinct, negative emotions common to seller reviews: anxiety and anger. In Studies 1 and 2, experimental methods were utilized to identify and explain the differential impact of anxiety and anger in terms of perceived reviewer effort. In Study 3, actual seller reviews from Yahoo! Shopping websites were collected to examine the relationship between emotional review content and helpfulness ratings. These findings demonstrate the importance of discriminating between discrete emotions in online word-of-mouth, and they have important repercussions for consumers and online retailers.

Sedan 1700-talet har läsarnas medverkan varit en väsentlig del i tidningarnas produktion. Utan deras deltagande har det inte heller blivit någon tidning. En förändring på området skedde när professionaliseringen av publicistrollen blev ett faktum och läsarnas medverkan ifrågasattes. Samhällsförändringar och tekniska utvecklingar har sedan lett fram till det vi har idag: ett samhälle där medieorganisationerna är i allt större behov av att läsarna återigen deltar i olika former. Syftet med studien är därför att undersöka hur journalister och ledning på tre olika lokaltidningar resonerar kring och förhåller sig till användargenererat material, samt vilka möjligheter användarna har att delta. Genom semistrukturerade intervjuer med lokaltidningarnas ansvariga utgivare och två journalister på respektive redaktion har vi fått fram att tidningarna generellt har ett positivt förhållningssätt till användargenererat material. De anser att teknikens utveckling både har hämmat och främjat relationen till läsarna i takt med att olika plattformer har utökat tidningarnas grundläggande publiceringskanal, det vill säga papperstidningen. Informanterna tror på ett ökat samarbete mellan yrkesverksamma journalister och användare i framtiden. De hävdar samtidigt att användarnas material inte får ta allt för stor plats och på så sätt konkurrera ut redaktionsmaterialet. Vidare menar de att yrkesprofessionen och de kunskaper som den omfattar är en av grundpelarna i tidningens funktion och så bör det förbli. I diskussionen använder vi oss av begrepp som offentlighet och deltagande samt resonemang kring det förändrade mediesammanhanget och den journalistiska yrkesprofessionen. / Since the eighteenth century user contribution has been a crucial part of newspaper production. Without the participation from the public there hasn’t been a newspaper at all. The professionalization of the publicist role became the starting point who changed how people valued user contribution. Societal change and the technical development has then led to the society we have today – a place where media organizations find themselves in a greater need for user participation to survive. The purpose of this study is therefore to examine how three local news papers reason about and react to user generated content and also to find out what possibilities the users have to participate. Thru semi structured interviews with the legally responsible publisher for each news paper and two journalists from each editorial staff our result shows that the news papers have a positive attitude towards user generated content in general. The informants say that the technological development have been both an improvement and inhibitory in the relationship to the readers. They believe in an increased cooperation in the future but at the same time emphasize the fact that user generated content can’t be allowed to take too much place and become a rival to the journalistic material. The informants also say that the knowledge they posses thru their journalistic education is the main core in their work as well as in the idea and function of the news paper. That is the way it should remain. We use terms and theories about the public sphere, participation, media convergence and the journalistic profession in our discussion.

This research has examined how Information and Communication Technologies (ICTs) can promote healthy eating habits amongst African Americans in low-income neighborhoods, a population that faces disproportionately high rates of diet-related health problems. In this dissertation, I describe the formative research I conducted to obtain system design guidelines and how I used those guidelines to develop two applications: EatWell and Community Mosaic. I also describe the results of the in-depth field studies I conducted to evaluate each application. Both EatWell and Community Mosaic incorporate the cultural construct of collectivism, a social orientation in which interdependence and communal responsibility are valued over individual goals and independence. As researchers have generally characterized the African American culture as collectivistic and argued for the value of designing collectivistic health interventions for this population, I examined the implications of taking such an approach to designing health promotion technologies. EatWell and Community Mosaic are collectivistic because they empower users to care for the health of their local community by helping others learn practical, locally-relevant healthy eating strategies. I discuss the results of my formative fieldwork and system evaluations, which characterize the value, challenge and nuances of developing community-based health information sharing systems for specific cultural contexts. By focusing on health disparities issues and the community social unit, I extend previous health technology research within Human-Computer Interaction (HCI). In particular, my results describe 1) a set of characteristics that help make shared material useful and engaging, 2) how accessing this information affects how people view the feasibility of eating well in their local context, 3) the way in which sharing information actually benefits the contributor by catalyzing personal behavior reflection, analysis and modification and 4) how sharing information and seeing that information's impact on others can help to build individuals' capacity to be a community health advocate. In addition, my work shows how examining cultural generalizations such as collectivism is not a straightforward process but one that requires careful investigation and appreciation for the way in which such generalizations are (or are not) manifested in the lives of individual people. I further contribute to HCI by presenting a set of important considerations that researchers should make when designing and evaluating community-based health systems. I conclude this dissertation by outlining directions for future HCI research that incorporates an understanding of the relationship between culture and health and that attempts to address health disparities in the developed world.

The availability and scale of user generated data in online systems raises tremendous challenges and opportunities to analytic study of human activities. Effective modeling of online human activities is not only fundamental to the understanding of human behavior, but also important to the online industry. This thesis focuses on developing models and algorithms to predict human activities in online systems and to improve the algorithmic design of personalized/socialized systems (e.g., recommendation, advertising, Web search systems). We are particularly interested in three types of online user activities, i.e., decision making, social interactions and user-generated contents. Centered around these activities, the thesis focuses on three challenging topics: 1. Behavior prediction, i.e., predicting users' online decisions. We present Collaborative-Competitive Filtering, a novel game-theoretic framework for predicting users' online decision making behavior and leverage the knowledge to optimize the design of online systems (e.g., recommendation systems) in respect of certain strategic goals (e.g., sales revenue, consumption diversity). 2. Social contagion, i.e., modeling the interplay between social interactions and individual behavior of decision making. We establish the joint Friendship-Interest Propagation model and the Behavior-Relation Interplay model, a series of statistical approaches to characterize the behavior of individual user's decision making, the interactions among socially connected users, and the interplay between these two activities. These techniques are demonstrated by applications to social behavior targeting. 3. Content mining, i.e., understanding user generated contents. We propose the Topic-Adapted Latent Dirichlet Allocation model, a probabilistic model for identifying a user's hidden cognitive aspects (e.g., knowledgability) from the texts created by the user. The model is successfully applied to address the challenge of ``language gap" in medical information retrieval.

In recent years emotion-related applications like smartphone apps that document and analyse the emotions of the user, have become very popular. But research also can deal with human emotions in a very technology-driven approach. Thus space-related emotions are of interest as well which can be visualised cartographically and can be captured in different ways. The research project of this dissertation deals with the extraction of georeferenced emotions from the written language in the metadata of Flickr and Panoramio photos, thus from user-generated content, as well as with their modelling and visualisation. Motivation is the integration of an emotional component into location-based services for tourism since only factual information is considered thus far although places have an emotional impact. The metadata of those user-generated photos contain descriptions of the place that is depicted within the respective picture. The words used have affective connotations which are determined with the help of emotional word lists. The emotion that is associated with the particular word in the word list is described on the basis of the two dimensions ‘valence’ and ‘arousal’. Together with the coordinates of the respective photo, the extracted emotion forms a georeferenced emotion. The algorithm that was developed for the extraction of these emotions applies different approaches from the field of computer linguistics and considers grammatical special cases like the amplification or negation of words. The algorithm was applied to a dataset of Flickr and Panoramio photos of Dresden (Germany). The results are an emotional characterisation of space which makes it possible to assess and investigate specific features of georeferenced emotions. These features are especially related to the temporal dependence and the temporal reference of emotions on one hand; on the other hand collectively and individually perceived emotions have to be distinguished. As a consequence, a place does not necessarily have to be connected with merely one emotion but possibly also with several. The analysis was carried out with the help of different cartographic visualisations. The temporal occurrence of georeferenced emotions was examined detailed. Hence the dissertation focuses on fundamental research into the extraction of space-related emotions from georeferenced user-generated content as well as their visualisation. However as an outlook, further research questions and core themes are identified which arose during the investigations. This shows that this subject is far from being exhausted. / In den letzten Jahren sind emotionsbezogene Anwendungen, wie Apps, die die Emotionen des Nutzers dokumentieren und analysieren, sehr populär geworden. Ebenfalls in der Forschung sind Emotionen in einem sehr technologiegetriebenen Ansatz ein Thema. So auch ortsbezogene Emotionen, die sich somit kartographisch darstellen lassen und auf verschiedene Art und Weisen gewonnen werden können. Das Forschungsvorhaben der Dissertation befasst sich mit der Extraktion von georeferenzierten Emotionen aus geschriebener Sprache unter Verwendung von Metadaten verorteter Flickr- und Panoramio-Fotos, d.h. aus nutzergenerierten Inhalten, sowie deren Modellierung und Visualisierung. Motivation hierfür ist die Einbindung einer emotionalen Komponente in ortsbasierte touristische Dienste, da diese bisher nur faktische Informationen berücksichtigen, obwohl Orte durchaus eine emotionale Wirkung haben. Die Metadaten dieser nutzergenerierten Inhalte stellen Beschreibungen des auf dem Foto festgehaltenen Ortes dar. Die dafür verwendeten Wörter besitzen affektive Konnotationen, welche mit Hilfe emotionaler Wortlisten ermittelt werden. Die Emotion, die mit dem jeweiligen Wort in der Wortliste assoziiert wird, wird anhand der zwei Dimensionen Valenz und Erregung beschrieben. Die extrahierten Emotionen bilden zusammen mit der geographischen Koordinate des jeweiligen Fotos eine georeferenzierte Emotion. Der zur Extraktion dieser Emotionen entwickelte Algorithmus bringt verschiedene Ansätze aus dem Bereich der Computerlinguistik zum Einsatz und berücksichtigt ebenso grammatikalische Sonderfälle, wie Intensivierung oder Negation von Wörtern. Der Algorithmus wurde auf einen Datensatz von Flickr- und Panoramio-Fotos von Dresden angewendet. Die Ergebnisse stellen eine emotionale Raumcharakterisierung dar und ermöglichen es, spezifische Eigenschaften verorteter Emotionen festzustellen und zu untersuchen. Diese Eigenschaften beziehen sich sowohl auf die zeitliche Abhängigkeit und den zeitlichen Bezug von Emotionen, als auch darauf, dass zwischen kollektiv und individuell wahrgenommenen Emotionen unterschieden werden muss. Das bedeutet, dass ein Ort nicht nur mit einer Emotion verbunden sein muss, sondern möglicherweise auch mit mehreren. Die Auswertung erfolgte mithilfe verschiedener kartographischer Visualisierungen. Eingehender wurde das zeitliche Auftreten der ortsbezogenen Emotionen untersucht. Der Fokus der Dissertation liegt somit auf der Grundlagenforschung zur Extraktion verorteter Emotionen aus georeferenzierten nutzergenerierten Inhalten sowie deren Visualisierung. Im Ausblick werden jedoch weitere Fragestellungen und Schwerpunkte genannt, die sich im Laufe der Untersuchungen ergeben haben, womit gezeigt wird, dass dieses Forschungsgebiet bei Weitem noch nicht ausgeschöpft ist.

Each day, millions of people ask questions and search for answers on the World Wide Web. Due to this, the Internet has grown to a world wide database of questions and answers, accessible to almost everyone. Since this database is so huge, it is hard to find out whether a question has been answered or even asked before. As a consequence, users are asking the same questions again and again, producing a vicious circle of new content which hides the important information. One platform for questions and answers are Web forums, also known as discussion boards. They present discussions as item streams where each item contains the contribution of one author. These contributions contain questions and answers in human readable form. People use search engines to search for information on such platforms. However, current search engines are neither optimized to highlight individual questions and answers nor to show which questions are asked often and which ones are already answered. In order to close this gap, this thesis introduces the \\emph{Effingo} system. The Effingo system is intended to extract forums from around the Web and find question and answer items. It also needs to link equal questions and aggregate associated answers. That way it is possible to find out whether a question has been asked before and whether it has already been answered. Based on these information it is possible to derive the most urgent questions from the system, to determine which ones are new and which ones are discussed and answered frequently. As a result, users are prevented from creating useless discussions, thus reducing the server load and information overload for further searches. The first research area explored by this thesis is forum data extraction. The results from this area are intended be used to create a database of forum posts as large as possible. Furthermore, it uses question-answer detection in order to find out which forum items are questions and which ones are answers and, finally, topic detection to aggregate questions on the same topic as well as discover duplicate answers. These areas are either extended by Effingo, using forum specific features such as the user graph, forum item relations and forum link structure, or adapted as a means to cope with the specific problems created by user generated content. Such problems arise from poorly written and very short texts as well as from hidden or distributed information.

No description available.

No description available.

Au lieu d’externaliser certaines tâches auprès de prestataires ayant recours à des pays dont la main d’œuvre est bon marché, les bibliothèques dans le monde font de plus en plus appel aux foules d’internautes, rendant plus collaborative leur relation avec les usagers. Après un chapitre conceptuel sur les conséquences de ce nouveau modèle économique sur la société et sur les bibliothèques, un panorama des projets est présenté dans les domaines de la numérisation à la demande, de la correction participative de l’OCR notamment sous la forme de jeux (gamification) et de la folksonomie. Ce panorama débouche sur un état de l’art du crowdsourcing appliqué à la numérisation et aux bibliothèques numériques et sur des analyses dans le domaine des sciences de l’information et de la communication. Enfin, sont présentées des apports conceptuels et des expérimentations originales, principalement autour du projet Numalire de numérisation à la demande par crowdfunding. / Instead of outsource tasks to providers in cheap labour countries, libraries increasingly appeal to online crowds, making relationship with their users more collaborative. The PhD begins with a conceptual chapter on the consequences of this new economic model on society and on libraries. Then, an overview of the projects is presented in the areas of digitization on demand (crowdfunding) and OCR correction with gamification and folksonomy. It is followed by a state of the art, a review and analysis on crowdsourcing applied to digitization and digital libraries. Finally, conceptual contributions and original experiments, with Numalire, a crowdfunding and digitization on demand project are presented.

Tendo em vista um cenário em que os dispositivos de registro do real adquirem onipresença na vida cotidiana, o jornalismo se encontra em um período de readequação de suas estratégias narrativas e de seu modus operandi. A presente tese procura investigar as reconfigurações no telejornalismo em razão da ubiquidade de câmeras, que capturam registros produzidos tanto pelas mídias quanto por instâncias externas a elas, e que oferecem aos veículos jornalísticos um material inesgotável e irrecusável, visto estar cercado de uma expectativa de autenticidade. Propõe-se então uma categorização às câmeras, sistematizadas como câmeras oniscientes e onipresentes, de modo a nos aproximarmos à especificidade do fenômeno. Em comum, todas as câmeras apontam à busca de uma estética realista, baseada no reconhecimento de uma baixa interferência midiática. Desse modo, o que se observa é o emprego de estratégias narrativas e estéticas para que o telejornalismo possa se apropriar destes conteúdos gerados por estas máquinas de visibilidade, que trazem às mídias algo que ficaria anteriormente restrito aos bastidores, operando também com sintoma da desfronteirização entre o público e o privado. A partir deste percurso metodológico, intenta-se por fim compreender de que forma estes dispositivos são utilizados para a concretização de novos efeitos de realismo ao jornalismo. / Considering a scenario where the technologic devices that visually register the world acquire omnipresence in everyday life, journalism is in a period of readjustment of its narrative strategies and its modus operandi. This research intents to investigate the changes in TV journalism because of the ubiquity of cameras, which capture images produced both by the media and by external institutions, since they offer to the journalistic enterprises an inexhaustible and irresistible material, because it is surrounded by an expectation of authenticity. We propose then a categorization of these machines, which are systematized as omniscient and omnipresent cameras, for the purpose of understanding the specificity of the phenomenon. In common, all of these cameras point to the search for a realistic aesthetics, based on the recognition of a low media interference. Thus, it is observed that the TV stations use some strategies to adapt these contents in their narratives, which bring to the media something that would previously be restrict to the backstage area. In a sense, they operate as a symptom o the erosion of the boundaries between public and private. With this methodological course, we finally attempt to understand how these technologic devices are used to achieve effects of realism to journalism.