<p>This research concerns exploiting knowledge of the user's environment (i.e., context information) to enrich a user's communication making it more personal, by ensuring that the user receives only relevant messages and calls in his/her current context, and to facilitate more opportunities for communication interactions with people that are in the same context and that share the same interests as this user. We describe in this licentiate thesis the concepts of context-addressed messaging and context-aware session control that enable users to: (1) send messages to others based on their context, rather than their network address and (2) to initiate, adapt, and terminate user's communication sessions based on this user's current context, respectively. These concepts address questions such as: how to discover, select, and switch to an optimal communication means to meet varying user, contextual, communication, and device resource requirements and preferences. A key to solving these problems is to create a representation of the user's context-dependent preferences and to process the user's context-dependent preferences which are part of context triggers. These context triggers can initiate a communication event upon a particular context update. Additionally, in order to provide the described context-aware communication functions, these mechanisms need timely access to the acquired (desired) context information. This in turn raises a plethora of other questions, such as how to discover sensors that provide the desired context information; how to acquire raw context data from these sensors; how to abstract, process, and model this data to become "understandable" to applications and system components; and how to distribute this context to applications that are running on different nodes.</p><p> </p><p>This research is split into three different parts. The first part concerns investigating and implementing context management functions. As part of this research we propose a novel approach for context synthesis using context operators. We also propose a design architecture for context-aware middleware that mediates between the sensors and applications, and that is able to share and retrieve context from other nodes in the network. The second part of our research concerns our proposed mechanism for context-addressed messaging. To implement this mechanism we designed our own message format, called the Common Profile for Context-Addressed Messaging (CPCAM) that is able to use any high level context to compose a context-based address. Additionally, we proposed to use context-based filtering to find the correct message recipients and determine if this message is relevant to these potential message recipients in their current context, as well as to deliver this message to the recipients' preferred device that is adapted using their preferred communication means. At the end of this second part we design context-addressed messaging system operations on top of a SIP and SIMPLE-based network infrastructure. The third part of our research describes context-aware session control mechanisms using context switch and context trigger constructs. A context-switch selects an action from a set of context-dependent actions upon an incoming communication event based on the receiver's current context. In contrast, a context trigger initiates an action based on a context update and the user's preferences that are specified in this updated context. This part illustrates in several examples the context-aware session control mechanisms, i.e. the initiation of a communication session based on the match of a user's preferences and current context, as well as adaptation and (if necessary) termination of an ongoing communication session based upon the user's context-dependent preferences.</p><p> </p><p>The research leading to this licentiate has created network and system level models necessary for implementation of a context-addressed communication system that would enable users to easily design their own personalized, context-aware communication services. The necessary constructs and properties of these models are designed and analyzed in the thesis, as well as in conference papers and other documents published in the process of doing the research for this thesis. A number of remaining open issues and challenges have been outlined as part of the future work.</p><p> </p> / EU FP6 MIDAS (Middleware Platform for Developing and Deploying Advanced Mobile Services) / EU FP6 MUSIC (Self-adapting Applications for Mobile Users In Ubiquitous Computing Environments)

The concept of the Internet of Things is driven by advancements of the Internet with the interconnection of heterogeneous smart objects using different networking and communication technologies. With the rapidly increasing number of interconnected devices present in the life of a person, providing authentication and secure communication between them is considered a key challenge. The integration of Wireless Sensor Networks in the Internet of Things creates new obstacles due to the necessity of finding a balance between the resources utilization and the applied security solutions. In multicast group communications, the energy consumption, bandwidth and processing overhead at the nodes are minimized in comparison to a point-to-point communication system. To securely transmit a message in order to maintain confidentiality of the data and the user’s privacy, usually involves human interaction or the pre-agreement upon some key, the latter unknown to an external attacker. In this thesis, the author proposed an authentication protocol based on the similar context between the correct devices and lightweight computationally secure group-key establishment, avoiding any kind of human involvement. The goal is achieved by having the devices calculate a fingerprint from their ambient context and through a fuzzy commitment scheme generating a commitment respectively opening value which is used to generate a common secret key between them. The tests are effected on real world data accumulated from different environments. The proposed scheme is based on elliptic curve cryptography and cryptographic one-way accumulators. Its feasibility is analyzed by implementing the group key establishment phase in the Contiki operating system and by simulating it with the Cooja simulator. Furthermore, the applicability of the protocol is analyzed and justified by an analysis of the storage overhead, communication overhead, and energy consumption. The simulator shows an energy consumption of only 112 mJ per node for group key establishment. The results obtained in this thesis demonstrate the feasibility of the scheme, it’s computational, and communication costs are further comparable to other similar approaches.

Chemistry is often claimed to be difficult, irrelevant, and uninteresting to school students. Even students who enjoy doing science often have problems seeing themselves as being scientists. This thesis explores and challenges the negative perception of chemistry by investigating upper secondary students’ views on the subject. Based on students’ ideas for improving chemistry education to make the subject more interesting and meaningful, new learning approaches rooted in context-based learning (CBL) are presented. CBL approaches are applied in several countries to enhance interest, de-emphasise rote learning, and improve students’ higher order thinking. Students’ views on upper secondary school chemistry classes in combination with their problem- solving strategies and application of chemistry content knowledge when solving context-based chemistry tasks were investigated using a mixed methods approach. Questionnaire responses, written solutions to chemistry problems, classroom observations, and think-aloud interviews with upper secondary students at the Natural Science Programme and with experts working on context- based chemistry tasks were analysed to obtain a general overview and explore specific issues in detail. Several students were identified who had positive feelings about chemistry, found it interesting, and chose to continue with it beyond the compulsory level, mainly with the aim of future university studies or simply because they enjoyed it. Their suggestions for improving school chemistry by connecting it to everyday life prompted an exploration of CBL approaches. Studies on the cognitive learning outcomes arising from the students’ work on context-based tasks revealed that school chemistry heavily emphasises the recall of memorised facts. However, there is evidence of higher order thinking when students’ problem-solving processes are scaffolded using hints based on the Model of Hierarchical Complexity in Chemistry (MHC-C). In addition, the contextualisation of problems is identified as something that supports learning rather than distracting students. To conclude, the students in this thesis are interested in chemistry and enjoy chemistry education, and their motives for choosing to study chemistry at the post-compulsory level are related to their aspirations; students’ identity formation is important for their choices. Because students are accustomed to recalling facts and solving chemistry problems that have “one single correct answer”, they find more open problems that demand higher order thinking (e.g. knowledge transfer) unfamiliar and complex, suggesting that such processes should be practiced more often in school chemistry. / Kemi är ett skolämne som generellt anses vara både svårt, irrelevant och ointressant för ungdomar. Trots att det ändå finns ungdomar som uppskattar naturvetenskap i allmänhet och kemi i synnerhet, har de ofta problem att se sig själva som naturvetare eller kemister. Denna avhandling undersöker och ifrågasätter den negativa bilden av kemiämnet genom att till en början studera gymnasieelevers syn på kemi. Med utgångspunkt från naturvetarelevers förslag för att förbättra kemiundervisningen och göra ämnet mer intressant och meningsfullt, anknyter avhandlingen därefter till kontextbaserad kemi. Kontextbaserade kurser används i flera länder för att öka elevernas intresse, minska fokuseringen på utantillkunskaper och utveckla elevernas mer avancerade tänkande; med andra ord med målet att uppnå ett meningsfullt lärande. Vid kontextbaserade angreppssätt utgår man från ett sammanhang (kontexten), ofta något personligt eller samhälleligt, som ska vara relevant och intressant. Från dessa kontexter koncentreras därefter undervisningen på de ämneskunskaper man behöver ha för att förstå sammanhanget (s.k. need-to-know). Syftet med avhandlingen är att undersöka naturvetarelevers syn på gymnasiekemin, både deras intresse för ämnet och deras skäl att välja det naturvetenskapliga programmet på gymnasiet, samt elevernas problemlösningsförmåga och användande av ämneskunskaper när de löser kontextbaserade kemiuppgifter. Skälet att studera naturvetarelever på gymnasiet är att dessa elever uppfattas som möjliga framtida naturvetare eftersom de själva har valt naturvetenskaplig inriktning efter den obligatoriska grundskolan. Med hjälp av olika metoder (enkäter, klassrums- observationer, skriftliga lösningar till kemiuppgifter och intervjuer med både elever och experter som löser kemiuppgifter) har analyser genomförts för att dels får en allmän överblick, dels för att utforska specifika delar i detalj både gällande kognitiva och affektiva aspekter av lärande. Resultaten visar att flertalet elever har en positiv inställning till kemi, många tycker att ämnet är intressant och har valt att fortsätta läsa kemi efter den obligatoriska grundskolan främst med målet att studera vidare på universitetsnivå, men också eftersom de specifikt uppskattar kemi. Gymnasieeleverna lyfter fram lärarna som viktiga och lärarstyrda kemilektioner anses positivt, speciellt om lärarna är strukturerade i sin undervisning. Ett vanligt skäl till att välja naturvetenskapsprogrammet är också att man aktivt väljer utbildning med utgångspunkt från vilken skola man vill gå på, något som i denna avhandling tolkas som ett identitetsskapande. Elevernas förslag för att förbättra skolkemin genom att anknyta kemin till vardagen låg till grund för avhandlingens fortsatta inriktning mot kontextbaserade angreppssätt. Analyser av elevernas kognitiva resultat när de löser kontextbaserade kemiuppgifter visar att dagens skolkemi tydligt fokuserar på att memorera faktakunskaper. Eleverna är vana att använda utantillkunskaper när de löser kemiuppgifter eftersom uppgifterna, enligt eleverna, efterfrågar ”det rätta svaret”. Däremot visar studierna också att ett mer avancerat tänkande kan uppnås när elevernas problemlösning stöds av hjälp och ledtrådar som baseras på ett specifikt ramverk, MHC-C (Model of Hierarchical Complexity in Chemistry). När det gäller ämneskunskaperna som krävs för att lösa de kontextbaserade kemiuppgifterna är vissa kemibegrepp viktiga tröskelbegrepp (sk. threshold concepts). Med hjälp av medvetenhet om tröskelbegrepp, som exempelvis polaritet och elektronegativitet för löslighetsuppgifter inom den organiska kemin, kan en större helhetsförståelse för övergripande begrepp (crosscutting disciplinary concepts) som förhållandet mellan kemiska ämnens struktur och egenskaper förhoppningsvis uppnås. När det gäller affektiva resultat anser eleverna att kontexterna i uppgifterna både var intressanta och relevanta, främst när en personlig anknytning var tydlig. Dessutom visade sig kontexterna i uppgifterna vara positiva för lärandet, inte en distraktionsfaktor. Sammanfattningsvis konstateras att svenska elever på naturvetenskaps- programmet är intresserade av kemi och uppskattar kemiundervisningen, speciellt om kemin knyts till vardagen och att lärarna har en tydlig struktur i sin undervisning. Elevernas skäl att välja fortsatta kemistudier efter den obligatoriska grundskolan kan knytas till deras utbildningssträvan men också att elevers identitetsskapande är viktigt för deras gymnasieval. Med hjälp av kontextbaserade angreppssätt kan kemiundervisningen göras mer intressant och relevant samtidigt som elevernas problemlösningsförmåga kan utvecklas. När eleverna möter mer öppna frågor som kräver förklaringar och resonemang är de ovana vid detta och uppfattar uppgifterna komplicerade, samtidigt som de uppskattar denna typ av uppgifter eftersom de uppfattas relevanta och intressanta. Slutsatsen blir att elevernas förmåga till problemlösning av öppna frågor som både kräver faktakunskaper men också förklaringar och resonemang måste tränas oftare inom ramen för skolans kemi för att utveckla elevernas meningsfulla lärande.

This research concerns exploiting knowledge of the user's environment (i.e., context information) to enrich a user's communication making it more personal, by ensuring that the user receives only relevant messages and calls in his/her current context, and to facilitate more opportunities for communication interactions with people that are in the same context and that share the same interests as this user. We describe in this licentiate thesis the concepts of context-addressed messaging and context-aware session control that enable users to: (1) send messages to others based on their context, rather than their network address and (2) to initiate, adapt, and terminate user's communication sessions based on this user's current context, respectively. These concepts address questions such as: how to discover, select, and switch to an optimal communication means to meet varying user, contextual, communication, and device resource requirements and preferences. A key to solving these problems is to create a representation of the user's context-dependent preferences and to process the user's context-dependent preferences which are part of context triggers. These context triggers can initiate a communication event upon a particular context update. Additionally, in order to provide the described context-aware communication functions, these mechanisms need timely access to the acquired (desired) context information. This in turn raises a plethora of other questions, such as how to discover sensors that provide the desired context information; how to acquire raw context data from these sensors; how to abstract, process, and model this data to become "understandable" to applications and system components; and how to distribute this context to applications that are running on different nodes.   This research is split into three different parts. The first part concerns investigating and implementing context management functions. As part of this research we propose a novel approach for context synthesis using context operators. We also propose a design architecture for context-aware middleware that mediates between the sensors and applications, and that is able to share and retrieve context from other nodes in the network. The second part of our research concerns our proposed mechanism for context-addressed messaging. To implement this mechanism we designed our own message format, called the Common Profile for Context-Addressed Messaging (CPCAM) that is able to use any high level context to compose a context-based address. Additionally, we proposed to use context-based filtering to find the correct message recipients and determine if this message is relevant to these potential message recipients in their current context, as well as to deliver this message to the recipients' preferred device that is adapted using their preferred communication means. At the end of this second part we design context-addressed messaging system operations on top of a SIP and SIMPLE-based network infrastructure. The third part of our research describes context-aware session control mechanisms using context switch and context trigger constructs. A context-switch selects an action from a set of context-dependent actions upon an incoming communication event based on the receiver's current context. In contrast, a context trigger initiates an action based on a context update and the user's preferences that are specified in this updated context. This part illustrates in several examples the context-aware session control mechanisms, i.e. the initiation of a communication session based on the match of a user's preferences and current context, as well as adaptation and (if necessary) termination of an ongoing communication session based upon the user's context-dependent preferences.   The research leading to this licentiate has created network and system level models necessary for implementation of a context-addressed communication system that would enable users to easily design their own personalized, context-aware communication services. The necessary constructs and properties of these models are designed and analyzed in the thesis, as well as in conference papers and other documents published in the process of doing the research for this thesis. A number of remaining open issues and challenges have been outlined as part of the future work. / EU FP6 MIDAS (Middleware Platform for Developing and Deploying Advanced Mobile Services) / EU FP6 MUSIC (Self-adapting Applications for Mobile Users In Ubiquitous Computing Environments)

This project takes a research through design approach, presenting the design process of an interactive sonic installation – SoundEscape – mounted on a walking bridge in Ørstedsparken, Copenhagen. SoundEscape makes people interact with sounds from rural areas of Denmark into the middle of the city. Featuring speakers and motion sensors, the prototype uses people crossing the bridge as an input for building up a soundscape – layer by layer as the person detected moves on. SoundEscape is just one prototype exploring how people can build up a soundscape through their movement across the bridge. The paper suggest more areas of the interactive design space to explore. Designing the installation, we went through four phases: field research, exploration synthesis, and concept development. Participants where included in the process to collect sound input from rural areas in Denmark. In all phases, we kept a close dialogue with the context, grounding design decisions in the observations and explorations we did on the bridge. We made two tests of the prototype: on a mini-scale model and in the park context. The paper presents a framework for interactive sonic installations that are used to analyse SoundEscape and compares it with another sonic installation on a bridge that have a different form of interactivity. Based on this analysis, the findings from the design process, and the two tests, the paper discuss the interactivity in the prototype. The paper suggest how the interactions with the soundscape can be further extended.

Den mobila användningen har ökat ordentligt de sista tio åren och smarttelefonen har blivit en viktig del av många människors vardag. Applikationer används i vår vardag och användningen av dessa kan reflektera vår vardag, dock så är gränssnittet på smarttelefonen statiskt och förändrar sig inte beroende på användarens plats och tid. Syftet med studien är att undersöka om användarupplevelsen går att främja med hjälp av en dynamisk hemskärm på en smarttelefon utifrån användarens plats och tid. Detta gjordes med hjälp av konceptdriven designforskning drivet av följande frågeställning: “Hur kan ett designkoncept av en dynamisk hemskärm på en smarttelefon teoretiskt förankras och konceptualiseras baserat på användarens plats och tid i syfte att främja användarupplevelsen? Konceptet grundar sig i tidigare forskning och resultatet blev ett koncept för dynamiska applikationsförslag som bemöttes av sju deltagarna som deltog i studien. Enligt deltagarna har konceptet en potential att minska stressen då navigering till rätt applikation underlättas. Konceptet var också enkelt att förstå men frågan kring integritet och säkerhet delade deltagarna. I resultatet presenteras designkonceptet som bygger på tidigare forskning samt kritiken från studiens deltagare. Konceptet har en potential och kan utforskas vidare från många olika perspektiv. / The mobile usage has increased considerably in the last ten years and the smartphone has become an important part of many people's everyday lives. Applications are used in our everyday life and the use of these can reflect our everyday lives, however, the interface on the smartphone is static and does not change depending on what context the user are in. The purpose of this study is to investigate whether the user experience can be favoured by a dynamic home screen on a smartphone based on the user's location and time. This was accomplished with the help of concept-driven design research driven by the following research question: "How can a design concept of a dynamic home screen on a smartphone be theoretically anchored and conceptualized based on the user's place and time in order to favour the user experience? The concept is based on previous research and the result was a concept for dynamic application suggestions that were met seven participants who participated in the study. According to the participants, the concept has the potential to reduce stress as navigation to the right application is facilitated. The concept was also easy to understand but the question of integrity and security shared the participants. In the result, the design concept is presented, which is based on previous research and the criticism from the study's participants. The concept has great potential and can be explored further from many different perspectives.

The main purpose of the study was to explore how learning cycle and traditional method as teaching methods contribute to the effect of contextual approach on 11th grade students&rsquo / achievement in &ldquo / impulse and momentum&rdquo / , and attitude towards physics. Therefore, a distinction between teaching approach (contextual vs. non-contextual) and teaching method (learning cycle vs. traditional method) was made and they were used as independent variables. Students&rsquo / gender was also used as an independent variable. Thus, the study was a 2x2x2 factorial design. The sample, drawn through the purposive sampling, included 226 students. Pretests and posttests were used for assessing students&rsquo / achievement in impulse and momentum, and attitude towards physics. Using Multivariate Analysis of Covariance (MANCOVA), the main effects of contextual approach, learning cycle, and student gender as well as the interaction effects among them were investigated. Consequently, (1) contextual approach was more effective in supporting students&rsquo / conceptual understanding of impulse and momentum, (2) learning cycle was as effective as the traditional method, (3) gender related difference in attitude towards physics in favor of males could not be removed through the treatments, (4) contextual approach worked better with the traditional method than the learning cycle for achievement and attitude, (5) males benefitted a little more from learning cycle while females benefitted a little more from traditional method in terms of conceptual and non-conceptual scores.

The purpose of the present study was to compare the effectiveness of context based instruction over traditionally designed chemistry instruction on 9th grade students&rsquo / understanding of cleaning materials topic and their attitudes toward environment. Moreover students&rsquo / science process skills were measured for using as a covariate. Participants were 222 ninth grade students from eight classes in two different types of high schools in Ankara. Experimental group students were instructed with context based instruction and control group students were instructed with traditionally designed instruction through five weeks. Cleaning Materials Achievement Test and Attitudes toward Environment Scale were used as pre and post tests. Science Process Skills test was used only as a pretest. MANCOVA technique was used as a statistical analysis procedure. According to statistical analyses, there was a significant mean difference with respect to context based instruction and traditionally designed instruction on cleaning materials topic in favor of experimental group and no significant difference with respect to attitude toward environment. There was no significant mean difference with respect to school type in both Cleaning Materials Achievement Test scores and Attitude toward Environment Scale scores. Beside, science process skills were a strong predictor for understanding the cleaning materials topic. Four focus groups were conducted separately regarding the students&rsquo / career choices after the treatment to have an idea over the quality of the instruction in experimental group. Focus group results revealed that students were appreciated and more motivated with context based instructional design.

The aim of study was to investigate the effect of context-based approach (CBA) through 5E learning cycle (LC) model over traditional instruction on students&rsquo / understanding, achievement, and chemical literacy on chemical reactions and energy concepts. The effect of instruction on students&rsquo / motivation to learn chemistry and the factors of motivation questionnaire were also explored. Additionally, the effect of gender difference was investigated. Six eleventh grade classes with 187 students taught by three teachers from two public Anatolian high schools of Ankara in 2011-2012 fall semester were enrolled in this study. Each teacher had experimental and control group. These classes were assigned randomly as experimental and control groups. The experimental groups were treated with CBA through 5E LC model, control groups were treated with traditional instruction. Chemical reactions and energy concept test and chemistry motivation questionnaire were administered as pre- and post-tests to groups. Achievement test and open-ended chemical literacy items on chemical reactions and energy were administered as post-tests to all groups. Science process skill test was administered to all groups at the beginning of the instruction. Multivariate Analysis of Covariance (MANCOVA) was used for the analysis of data. The results revealed that CBA through 5E LC model was superior to traditional instruction on students&rsquo / understanding, achievement, and chemical literacy in the chemical reactions and energy unit. Although, students&rsquo / overall motivation scores did not changed across the groups, experimental groups intrinsic motivation and relevance of learning chemistry to personal goals was superior than control groups. No gender difference was found.

O codificador aritmético binário adaptativo ao contexto adotado (CABAC – Context-based Adaptive Binary Arithmetic Coding) pelo padrão H.264/AVC a partir de perfil Main é o estado-da-arte em termos de eficiência de taxa de bits. Entretanto, o CABAC ocupa 9.6% do tempo total de processamento e seu throughput é limitado pelas dependências de dados no nível de bit (LIN, 2010). Logo, atingir os requisitos de desempenho em tempo real nos níveis mais altos do padrão H.264/AVC se torna uma tarefa árdua em software, sendo necesário então, a aceleração do CABAC através de implementações em hardware. As arquiteturas de hardware encontradas na literatura para o CABAC focam no Codificador Aritmético Binário (BAE - Binary Arithmetic Encoder) enquanto que a Binarização e Modelagem de Contextos (BCM – Binarization and Context Modeling) fica em segundo plano ou nem é apresentada. O BCM e o BAE juntos constituem o CABAC. Esta dissertação descreve detalhadamente o conjunto de algoritmos que compõem o BCM do padrão H.264/AVC. Em seguida, o projeto de uma arquitetura de hardware específica para o BCM é apresentada. A solução proposta é descrita em VHDL e os resultados de síntese mostram que a arquitetura alcança desempenho suficiente, em FPGA e ASIC, para processar vídeos no nível 5 do padrão H.264/AVC. A arquitetura proposta é 13,3% mais rápida e igualmente eficiente em área que os melhores trabalhos relacionados nestes quesitos. / Context-based Adaptive Binary Arithmetic Coding (CABAC) adopted in the H.264/AVC main profile is the state-of-art in terms of bit-rate efficiency. However, CABAC takes 9.6% of the total encoding time and its throughput is limited by bit-level data dependency (LIN, 2010). Moreover, meeting real-time requirement for a pure software CABAC encoder is difficult at the highest levels of the H.264/AVC standard. Hence, speeding up the CABAC by hardware implementation is required. The CABAC hardware architectures found in the literature focus on the Binary Arithmetic Encoder (BAE), while the Binarization and Context Modeling (BCM) is a secondary issue or even absent in the literature. Integrated, the BCM and the BAE constitute the CABAC. This dissertation presents the set of algorithms that describe the BCM of the H.264/AVC standard. Then, a novel hardware architecture design for the BCM is presented. The proposed design is described in VHDL and the synthesis results show that the proposed architecture reaches sufficiently high performance in FPGA and ASIC to process videos in real-time at the level 5 of H.264/AVC standard. The proposed design is 13.3% faster than the best works in these items, while being equally efficient in area.