This master’s thesis project “A Presence Server for Context-aware Applications” was carried out at KTH Center for Wireless Systems (Wireless@KTH). The overall goal of this thesis project is to implement a context aware infrastructure to serve as middleware for different kinds of context aware applications, such as a context-aware printing application, location based notifier application, etc. This thesis examines different types of context aware architectures and considers different forms of context modeling. Additionally the thesis also explores some of the related technology, in order to provide the reader with suitable background information to understand the rest of the thesis. By using the SIP Express Router (SER) and its presence module (pa) a context server has been designed, implemented, and evaluated. Evaluation reveals that the critical bottleneck is the increasing service time as the number of Publish messages for different events in the SER database increases, i.e. the time required for handling and sending the Notify messages when a new Publish message is received increases as a function of the number of earlier Publish messages. The evaluation also shows that the dependence of SER upon the MySQL database as incorrect database queries can cause SER to crash. Additionally the performance of the database limits the performance of the context server. A number of future improvements are necessary to address security issues (in particular the authentication of Watchers) and adding policy based control in order to send Notify messages only to the Watchers authorized to receive information for a specific event. / Examensarbetet "A Presence Server for Context-aware Applications" genomfördes på Kungliga Tekniska Högskolan, KTH Center for Wireless Systems (Wireless@KTH). Det övergripande målet med detta examensarbetsprojekt är att implementera en kontextmedveten infrastruktur som fungerar som "middleware" för olika typer av kontextmedvetna applikationer. Exempel på dessa är kontextmedveten utskriftsapplikation och platsberoende meddelarapplikation osv. Rapporten undersöker olika typer av kontextmedvetna arkitekturer och betraktar olika former av kontextmodellering. Rapporten utforskar även vissa besläktade teknologier för att kunna tillhandahålla läsaren med en passande bakgrundsinformation och därmed öka förståelsen för resten av examensarbetet. Genom att använda Sip Express Routern (SER) och dess närvaromodul (presence module, PA) har en kontextserver designats, implementerats och utvärderats. Utvärderingen visar att den kritiska flaskhalsen är tiden det tar för SER servern att svara på nya Publish meddelanden, för olika händelser, i SER databasen. Svarstiden ökar allteftersom databasen fylls med mer data. Detta påverkar hantering och sänding av Notify meddelande när en ny Publish meddelande är mottagen. Uvärderingen visar också att en viktig fråga är relationen mellan SER servern och MySQL databasen, eftersom felaktiga förfrågningar till databasen kan krascha SER servern. De viktigaste framtida förbättringarna är säkerhetsaspekter (mer specifikt autenticering av Watchers) och tillägg av policybaserad sändning av Notify meddelanden endast till auktoriserade Watchers för specifika händelser.

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The aim of this study was to examine how UMEVA, a company responsible for taking care of the waste in Umeå municipalty, are communicating with their costumers and what their main message with their communication is. I wanted to analyse how UMEVA ́s goals regarding sustainable development and other environmental issues are reflected in their communication towards their costumers and how they are trying to create an environment awarness with their costumers. The theories used in this essay are substantially based or developed from strucuralism. To find discourses in the material I used the theories of Saussure and Barthes regarding semiotics to discribe words, signs and pictures. To further discover discourses in the communication I have applied Foucaults, Mouffe and Laclau ́s theories to see how words collaborate to create a meaning. To investigate how UMEVA are directing their communication I have used Stuart Halls theories regarding encoding and decoding. To find discourses I analysed the language and pictures that are used in the material using rethoric and discourse analysis, together with semiotic analysis. The material analysed are folders and a calender regarding recycling and re-using that are ment for UMEVA ́s costumers. I also analysed the information on UMEVA ́s website conserning their goals and policy ́s concerning the environment. The results from the analyses show that the presence of the environment discourse is constant through the material. UMEVA are not clear regarding how to achieve their environmental goals, they are however constant throughout the material that their intent is to make the costumers recycle and be more aware of the environment. To convince the costumers UMEVA are directing the information towards the costumers using different kinds of techniques, first of all by using the word ”you” constantly. Another persuation technique is that they are aiming for the costumers conscience, the ability to make a difference for the future, and last but not least, the economic aspect with the opportunity to save money. The question that remains is if this kind of communication is effective on those not already aware of their impact on the environment.  Keywords: communication, sustainable development, information, message

Static authentication, where user identity is checked once at login time, can be circumvented no matter how strong the authentication mechanism is. Through attacks such as man-in-the-middle and its variants, an authenticated session can be hijacked later after the initial login process has been completed. In the last decade, continuous authentication (CA) using biometrics has emerged as a possible remedy against session hijacking. CA consists of testing the authenticity of the user repeatedly throughout the authenticated session as data becomes available. CA is expected to be carried out unobtrusively, due to its repetitive nature, which means that the authentication information must be collectible without any active involvement of the user and without using any special purpose hardware devices (e.g. biometric readers). Stylometry analysis, which consists of checking whether a target document was written or not by a specific individual, could potentially be used for CA. Although stylometric techniques can achieve high accuracy rates for long documents, it is still challenging to identify an author for short documents, in particular when dealing with large author populations. In this dissertation, we propose a new framework for continuous authentication using authorship verification based on the writing style. Authorship verification can be checked using stylometric techniques through the analysis of linguistic styles and writing characteristics of the authors. Different from traditional authorship verification that focuses on long texts, we tackle the use of short messages. Shorter authentication delay (i.e. smaller data sample) is essential to reduce the window size of the re-authentication period in CA. We validate our method using different block sizes, including 140, 280, and 500 characters, and investigate shallow and deep learning architectures for machine learning classification. Experimental evaluation of the proposed authorship verification approach based on the Enron emails dataset with 76 authors yields an Equal Error Rate (EER) of 8.21% and Twitter dataset with 100 authors yields an EER of 10.08%. The evaluation of the approach using relatively smaller forgery samples with 10 authors yields an EER of 5.48%. / Graduate

Master of Science / Department of Journalism and Mass Communications / Louise Benjamin / This experimental research builds upon the health communications study completed by Rustam Haydarov in 2010, with a similar approach to ascertain how an individual’s age might influence their reaction to political messages. Using a typology of frames by Levin, Schneider and Gaeth (1998), the study utilizes an older demographic (ages 55-70) and a younger comparison group (ages 18-33) to determine a) if both groups find positive advertising messages more favorable than negative advertising messages and b) if the older demographic is more wary than younger counterparts when discussing current events and the future of America. The study used a combination of qualitative and quantitative methods to determine reactions to goal-oriented and loss-oriented message framing in four mock print political campaign advertisements focusing on the topics of healthcare and college education financing. There was greater prevalence of strongly negative and strongly positive reactions among the younger demographic, except in the case of the loss-framed healthcare ad. The older group reacted more strongly to that particular ad, concerning an issue which had great relevance to them. Of the two age groups, the older demographic registered a more even-keeled reaction across the four ads. Overall, this study has focused on how message frame, topic and age of the message receiver combine to affect message resonance in the context of political communications.

Background- Communication messages today are all about influencing and persuading people. Two main types of messages can be seen when studying the healthy food trend on Instagram and how it is impacting attitude formation and change; these two are positive and negative messages. However, different communication messages are not the only deciders of attitude formation and change. There is one more significant factor that impacts attitude formation and change; this factor is identification with the message sender. Purpose- The purpose of this thesis is to identify whether positively or negatively themed messages on Instagram have a stronger impact on a person's attitudes regarding healthy food consumption. We will further examine if identification with the message sender additionally impacts attitude formation and change. Method- In order to fulfill the purpose of the thesis we used a qualitative research approach. We conducted interviews with 40 respondents that belonged to our main target group. Furthermore we conducted a robustness check with six respondents. All 46 respondents included in the qualitative study were Instagram users, and all the respondents in the main target group were students. Findings and Conclusion- After analyzing the empirical results together with suitable theories, some main conclusions could be drawn. The study demonstrated that positive communication messages are the preferred message type on Instagram. We further conclude that identification with the message sender does indeed have an additional impact on attitude formation and change. Based on this study we can say that communication messages and identification with the message sender work together in forming and changing attitudes regarding healthy food on Instagram. Practical Implications- This thesis gives valuable indications to companies, organizations and decision makers in order to direct marketing practices in terms of communication messages on social media, particularly Instagram. Moreover it gives insights for managers to be able to create communication messages that correspond to the expectations of the society. Keywords- Communication messages, attitude formation and change, identification with the message sender.

The objective of the study is to extend the emerging body and scope of research on consumer’s attitudinal and behavioral responses to online consumer reviews by examining the role of both message content and source characteristics. That is, this study investigates how consumers process online consumer reviews within the context of message and source characteristics, and how these two factors influence consumer’s attitudes toward the review, attitudes toward the product, perceived credibility of the reviewers, and purchase intention. From this perceptive, the study broadens the understanding and importance of message and source factors to the persuasiveness of online consumer reviews. / text

This exploratory study examined the effect of cross-culture on the content of messages on message boards, more specifically through the sitcom programs shown in United States and Taiwan. The theoretical framework is based on the theory of culture: Individualism vs. Collectivism. However as shown in the study factors such as country of origin as well as viewers’ profile will play a role and have its effect in the findings. Content analysis was applied to analyze the data. The results of this study have important implications for cross-cultural consumer studies and marketing practices. The practical research involved analyzing an organization’s data utilizing data mining tools with the objective of customers and products segmentations. The report ends by pointing out areas for future research. / This exploratory study examined the effect of cross-culture on the content of messages on message boards, more specifically through the sitcom programs shown in United States and Taiwan. The theoretical framework is based on the theory of culture: Individualism vs. Collectivism. However as shown in the study factors such as country of origin as well as viewers’ profile will play a role and have its effect in the findings. Content analysis was applied to analyze the data. The results of this study have important implications for cross-cultural consumer studies and marketing practices. The practical research involved analyzing an organization’s data utilizing data mining tools with the objective of customers and products segmentations. The report ends by pointing out areas for future research.

Text message reminders have proven effective for positive behavioral changes in medicine, but their influence on oral hygiene compliance has never been tested. This study aimed to determine if text message reminders about oral hygiene have an influence on the level of compliance. In this prospective randomized controlled clinical trial, 42 orthodontic patients were assigned to a text message or control group. Parents of patients assigned to the text message group received a reminder text message one weekday each week. Oral hygiene compliance was measured using bleeding index, modified gingival index, plaque index, and visual examination of white spot lesion development at baseline (T0), two appointments after baseline (T1), and four appointments after baseline (T2). Bleeding index, modified gingival index, and plaque index scores were significantly lower in the text message group than the control group at T2. A text message reminder system is effective for improving oral hygiene compliance in orthodontic patients.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.