This study proposes and evaluates a new method for Web archiving. We leverage the caching infrastructure in Web servers for archiving. Redis is used as the page cache and its persistence mechanism is exploited for archiving. We experimentally evaluate the performance of our archival technique using the Greek version of Wikipedia deployed on Amazon cloud infrastructure. We show that there is a slight increase in latencies of the rendered pages due to archiving. Though the server performance is comparable at larger page cache sizes, the maximum throughput the server can handle decreases significantly at lower cache sizes due to more disk write operations as a result of archiving. Since pages are dynamically rendered and the technology stack of Wikipedia is extensively used in a number of Web applications, our results should have broad impact. / Master of Science / This study proposes and evaluates a new method for Web archiving. To reduce response time for serving webpages, Web Servers store recently rendered pages in memory. This process is known as caching. We modify this caching mechanism of Web Servers for archival. We then experimentally evaluate the impact of our archival technique on Web Servers. We observe that the time to render a Web page increases slightly as long as the Web Server is under moderate load. Through our experiments, we establish limits on the maximum requests a Web Server can handle without increasing the response time. We ensure our experiments are conducted on Web Servers using technologies that are widely used today. Thus our results should have broad impact.

This thesis is called “Citation needed – the perceived credibility of Wikipedia among higheducation students”. The purpose of this thesis is to discover the opinions about the credibilityof Wikipedia among high education students. The assumption is that students are aware ofbeing source criticizing and do not directly cite Wikipedia in academic works. The main research question is: what are the views of the perceived credibility of theinformation on Wikipedia among high education students? The theoretical framework is made out of previous research specific related to Wikipediabut also theories around memory creation, assessment of sources and credibility. The method used is qualitative, with semi-structured interviews. The material consists ofinterviews with nine participants. Their answers are transcribed and presented in themes andthen analyzed. The main results are that the perceived credibility of the information on Wikipedia amongthe students is that it is fairly credible and their views of the encyclopedia are that it is fastupdated and neutral. They also believe that Wikipedia isn’t for academic usage so in allaspects the students do not make a thoroughly assessment of the encyclopedia’s credibility. Further implications are that Wikipedia would be ruined if anyone tried to make itacademic. Wikipedia fulfills an educational tool for the public even though it is not alwayscorrect. It is important to be reminded that Wikipedia contains errors but no other source iscompletely flawless either. In that sense it would be smarter to start a new encyclopedia, ifthere is such a need, perhaps open for professors only and would in the end only containvetted information, however mostly/only in academic fields. The length of the thesis is 56 pages in total and approximately 21 000 words. Keywords: Wikipedia, encyclopedias, source criticism, credibility, Nationalencyclopedin,students, in-depth interviews.

This dissertation describes WikiRank, an unsupervised method of assigning relative values to elements of a broad coverage encyclopedic information source in order to identify those entries that may be relevant to a given piece of text. The valuation given to an entry is based not on textual similarity but instead on the links that associate entries, and an estimation of the expected frequency of visitation that would be given to each entry based on those associations in context. This estimation of relative frequency of visitation is embodied in modifications to the random walk interpretation of the PageRank algorithm. WikiRank is an effective algorithm to support natural language processing applications. It is shown to exceed the performance of previous machine learning algorithms for the task of automatic topic identification, providing results comparable to that of human annotators. Second, WikiRank is found useful for the task of recognizing text-based paraphrases on a semantic level, by comparing the distribution of attention generated by two pieces of text using the encyclopedic resource as a common reference. Finally, WikiRank is shown to have the ability to use its base of encyclopedic knowledge to recognize terms from different ontologies as describing the same thing, and thus allowing for the automatic generation of mapping links between ontologies. The conclusion of this thesis is that the "knowledge access heuristic" is valuable and that a ranking process based on a large encyclopedic resource can form the basis for an extendable general purpose mechanism capable of identifying relevant concepts by association, which in turn can be effectively utilized for enumeration and comparison at a semantic level.

In der Mitte der Dissertation steht die Frage nach den Koordinationsmustern und den institutionellen Bedingungen online-medialen gelingenden, produktiven, also das Generieren informationeller Güter bezweckenden, Zusammenarbeitens. Diese wird exemplarisch und exponiert am Beispiel der freien Gemeingüterproduktion studiert, genauer gesagt am Fall der Online-Enzyklopädie Wikipedia. Die Studie zeigt, wie und in welchen institutionellen Kontexten das Herstellen und Verwalten informationeller Gemeingüter durch online-medial vermitteltes Kooperieren gelingen kann. Dazu wurde eine dreijährige teilnehmende Beobachtung durchgeführt und mit qualitativen Interviews und Dokumentenanalysen methodisch kombiniert. Typologisiert wurden die Beteiligungsweisen, die es Wikipedianern erlauben, an dem Projekt konstruktiv teilzunehmen, konkret die Handlungsmuster, um Beteiligen zu formieren und dabei unbezahltes und zielorientiertes Editieren zu animieren, anzuleiten und vorzulegen, sowie Handlungsmuster des Qualifizierens von Beiträgen und Beiträgern als Beobachten, Auszeichnen und Ausschließen. Das dabei effektive institutionelle Ensemble wurde als Satz an Richtlinien und Codevorgaben sowie normativen Einstellungen in Bezug auf das Arbeitsethos der Wikipedianer, die Form ihrer Vergemeinschaftung, das Teilnehmerkonzept und das enzyklopädische Werkkonzept ermittelt.

In der Mitte der Dissertation steht die Frage nach den Koordinationsmustern und den institutionellen Bedingungen online-medialen gelingenden, produktiven, also das Generieren informationeller Güter bezweckenden, Zusammenarbeitens. Diese wird exemplarisch und exponiert am Beispiel der freien Gemeingüterproduktion studiert, genauer gesagt am Fall der Online-Enzyklopädie Wikipedia. Die Studie zeigt, wie und in welchen institutionellen Kontexten das Herstellen und Verwalten informationeller Gemeingüter durch online-medial vermitteltes Kooperieren gelingen kann. Dazu wurde eine dreijährige teilnehmende Beobachtung durchgeführt und mit qualitativen Interviews und Dokumentenanalysen methodisch kombiniert. Typologisiert wurden die Beteiligungsweisen, die es Wikipedianern erlauben, an dem Projekt konstruktiv teilzunehmen, konkret die Handlungsmuster, um Beteiligen zu formieren und dabei unbezahltes und zielorientiertes Editieren zu animieren, anzuleiten und vorzulegen, sowie Handlungsmuster des Qualifizierens von Beiträgen und Beiträgern als Beobachten, Auszeichnen und Ausschließen. Das dabei effektive institutionelle Ensemble wurde als Satz an Richtlinien und Codevorgaben sowie normativen Einstellungen in Bezug auf das Arbeitsethos der Wikipedianer, die Form ihrer Vergemeinschaftung, das Teilnehmerkonzept und das enzyklopädische Werkkonzept ermittelt.:1 Einleitung: Online-Kooperation in Theorie und Praxis 4 2 Problem: Wie gelingt Kooperation online? 15 2.1 Untersuchungsfeld: Gemeingüterproduktion 15 2.2 Wie ist Gemeingüterproduktion möglich? 31 2.3 Problemkreise 49 3 Theoretischer Rahmen: Online-Kooperation in Aktion 54 3.1 Die Praxis sozialer Ordnung 54 3.2 Online-Kooperation koordinieren 77 3.3 Bilanz und Forschungsfragen: Gemeingüter produzieren 100 4 Methodologie, Methoden und Vorgehen: Online-Kooperieren studieren 108 4.1 Methodologische Herausforderung: Logik der Praxis vs. Logik der Logik? 108 4.2 Methodische Option: Praktiken beobachten, Praktiken vollziehen, Praktiken beschreiben 111 4.3 Konzeption und Fallauswahl 130 4.4 Vorgehen 147 5 Analyse: Gemeingüter produzieren 171 5.1 Einen ausgezeichneten Artikel schreiben oder: Wikipedia macht Arbeit 172 5.2 Beteiligungsweisen: „und eigentlich ist doch alles ganz einfach“ 181 5.3 Wikipedias institutionelles Ensemble: „eine komplizierte Materie“ 205 5.4 Beteiligen formieren: „in die richtige Spur gesetzt“ 286 5.5 Beteiligen qualifizieren: „wir bemühen uns, alles richtig zu machen“ 313 6 Bilanz und Aufgaben: Den ‚Wikiweg’ gehen? 336 7 Anhang 353 Abbildungsverzeichnis 405 Tabellenverzeichnis 406 Primärquellenverzeichnis 407 Sekundärquellenverzeichnis 416

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Wikipedia är en samling digitala encyklopedier som alla får skriva på och redigera. Skrivarbasen är dock kraftigt mansdominerad, trots att Wikipedia försöker få en skrivarbas som skulle kunna ses som representativ för verkligheten. För att undersöka varför så har en mindre explorativ studie på svenska Wikipedias diskussionsklimat genomförts. Studenter vid KTH har fått läsa utdrag ur diskussioner, och svarat på frågor om hur de upplever diskussionsklimatet och hur deras motivation att delta i diskussionen påverkas av det. Resultatet visar att de kvinnor som har svarat i intervjuerna i större grad än män blir omotiverade att delta i diskussionsklimat som de upplever som obehagliga. Studien ger förslag på framtida studier som skulle kunna genomföras på området. / Wikipedia is a collection of digital encyclopedia that anyone can write and edit. The writers, however, are a male dominated group, despite the fact that Wikipedia is trying to get a writer base that could be seen as representative of society. To investigate why this is a small-scale exploratory study of Swedish Wikipedia's discussion climate has been implemented. A small group of students at KTH have been studied. The interviewees have read excerpts from discussions taken from Swedish Wikipedia and answered questions about how they perceive them and how their motivation to participate in the discussion is affected by their climate. The result shows that the women that have answered the interviews have felt unmotivated to partake in discussions they feel are being conducted poorly to a greater extent than the men who have answered. The study provides ideas for future studies on the discussion climate of Swedish Wikipedia.

Nous abordons dans cette thèse quelques-unes des questions soulevées par I'émergence d'applications sociales sur le Web, en se concentrant sur deux axes importants: l'efficacité de recherche sociale dans les applications Web et l'inférence de liens sociaux signés à partir des interactions entre les utilisateurs dans les applications Web collaboratives. Nous commençons par examiner la recherche sociale dans les applications de "tag- ging". Ce problème nécessite une adaptation importante des techniques existantes, qui n'utilisent pas des informations sociaux. Dans un contexte ou le réseau est importante, on peut (et on devrait) d'exploiter les liens sociaux, ce qui peut indiquer la façon dont les utilisateurs se rapportent au demandeur et combien de poids leurs actions de "tagging" devrait avoir dans le résultat. Nous proposons un algorithme qui a le potentiel d'évoluer avec la taille des applications actuelles, et on le valide par des expériences approfondies. Comme les applications de recherche sociale peut être considérée comme faisant partie d'une catégorie plus large des applications sensibles au contexte, nous étudions le problème de répondre aux requêtes à partir des vues, en se concentrant sur deux sous-problèmes importants. En premier, la manipulation des éventuelles différences de contexte entre les différents points de vue et une requête d'entrée conduit à des résultats avec des score incertains, valables pour le nouveau contexte. En conséquence, les algorithmes top-k actuels ne sont plus directement applicables et doivent être adaptés aux telle incertitudes dans les scores des objets. Deuxièmement, les techniques adaptées de sélection de vue sont nécessaires, qui peuvent s’appuyer sur les descriptions des requêtes et des statistiques sur leurs résultats. Enfin, nous présentons une approche pour déduire un réseau signé (un "réseau de confiance") à partir de contenu généré dans Wikipedia. Nous étudions les mécanismes pour deduire des relations entre les contributeurs Wikipédia - sous forme de liens dirigés signés - en fonction de leurs interactions. Notre étude met en lumière un réseau qui est capturée par l’interaction sociale. Nous examinons si ce réseau entre contributeurs Wikipedia représente en effet une configuration plausible des liens signes, par l’étude de ses propriétés globaux et locaux du reseau, et en évaluant son impact sur le classement des articles de Wikipedia. / We address in this thesis some of the issues raised by the emergence of social applications on the Web, focusing on two important directions: efficient social search inonline applications and the inference of signed social links from interactions between users in collaborative Web applications. We start by considering social search in tagging (or bookmarking) applications. This problem requires a significant departure from existing, socially agnostic techniques. In a network-aware context, one can (and should) exploit the social links, which can indicate how users relate to the seeker and how much weight their tagging actions should have in the result build-up. We propose an algorithm that has the potential to scale to current applications, and validate it via extensive experiments. As social search applications can be thought of as part of a wider class of context-aware applications, we consider context-aware query optimization based on views, focusing on two important sub-problems. First, handling the possible differences in context between the various views and an input query leads to view results having uncertain scores, i.e., score ranges valid for the new context. As a consequence, current top-k algorithms are no longer directly applicable and need to be adapted to handle such uncertainty in object scores. Second, adapted view selection techniques are needed, which can leverage both the descriptions of queries and statistics over their results. Finally, we present an approach for inferring a signed network (a "web of trust")from user-generated content in Wikipedia. We investigate mechanisms by which relationships between Wikipedia contributors - in the form of signed directed links - can be inferred based their interactions. Our study sheds light into principles underlying a signed network that is captured by social interaction. We investigate whether this network over Wikipedia contributors represents indeed a plausible configuration of link signs, by studying its global and local network properties, and at an application level, by assessing its impact in the classification of Wikipedia articles.javascript:nouvelleZone('abstract');_ajtAbstract('abstract');

The purpose of this study was to identify certain experiences among Swedish scholars towards their use of Wikipedia. The goal was to create a deeper understanding of how audiences with academic professions experience Wikipedia as a place to share knowledge with other individuals. This study was done through the perspectives of the ANT theory (Latour, 2005) and the User-Gratification theory (Katz et al., 1973). The method of choice was a mixed method research where the primary choice of method was qualitative interviews with seven Swedish scholars and one expert interview consisting of an employee at the Swedish Wikimedia foundation. This material was analyzed through a thematic analysis. Some of the findings from the interview was also analyzed through a computational network analysis to provide deeper insight into the concept of Wikipedia.    The research showed that there is a variated view on the scholar’s role on Wikipedia. While some of the participants criticized the structure in which the information was produced, some raised awareness into the importance to provide society with reliable and scientific knowledge in which important decisions can be based on. Different actors within the network of Wikipedia were identified which provided a deeper insight into the variety of individuals and non-human elements that work together to generate content on Wikipedia. A few of these actors and their relationships between one another was also visualized during the study. This provided even further analytical insight to Wikipedia as a platform. The overall view among the participants showed that there is a lack of incitement on how and why scholars should contribute to Wikipedia in Sweden. The results also showed that there are a variety of ways in which the platform of Wikipedia can be viewed depending on personal use the website. The cultural approach to Wikipedia was discussed in the context to how Wikipedia can provide society with information and how this might act as a form of cultural heritage online. / Syftet med denna studie var att identifiera vissa erfarenheter bland svenska forskares användning av Wikipedia. Målet med studien var att skapa en djupare förståelse för hur mediepubliker med akademiska yrken upplever Wikipedia som en plats att dela kunskap med andra individer. Studien genomfördes med hjälp av de olika perspektiven som de teoretiska utgångspunkterna ANT teorin (Latour, 2005) och användare-belönings teorin (Katz et al., 1973) bidrog med. Valet av metod blev en blandad metodforskning där det primära metodvalet var kvalitativa intervjuer med sju olika svenska akademiker och en expertintervju med en anställd på Wikimedia Sverige. Det insamlande materialet blev sedan analyserat genom en tematisk analys. Vissa delar av det insamlade materialet blev senare också analyserat genom en nätverksanalys av data för att bidra med djupare kunskap kring konceptet Wikipedia.    Studien visade att det finns en varierad syn på forskarens roll på Wikipedia. Medan vissa deltagare kritiserade strukturen som informationen produceras i, utryckte sig andra kring vikten av att bidra med trovärdig kunskap till samhället som sedan kan ligga till grund för olika beslut. Olika aktörer inom Wikipedia identifierades vilket också bidrog till en djupare insikt i den variation av individer och icke-mänskliga element som jobbar tillsammans för att skapa material på Wikipedia. Vissa av dessa aktörers relationer med varandra identifierades också genom olika typer av visuella element som framställdes under studien. Detta bidrog således också med en djupare analytisk insikt kring Wikipedia som plattform. Den allmänna synen bidrog också med insikt i den bristen på incitament kring hur och varför forskare bör bidra med sin forskning på Wikipedia i Sverige. Resultaten visade också att det finns en mängd olika sätt individer kan skapa sin bild av Wikipedia genom sitt personliga bruk av plattformen. Den kulturella approachen till Wikipedia diskuterades också genom kontexten hur plattformen kan bidra samhället med information och hur detta kan uppfattas som ett kulturellt arv online.