Dissertations / Theses on the topic 'Context-aware'
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Oukhay, Younes. "Context Aware Services." Thesis, KTH, Kommunikationssystem, CoS, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92259.
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Today customization of services and applications is one of the major challenges in facilitating ease of use. More and more people are interested in context aware services. In this work, I will study context awareness: What contributions can it make? What technical issues are raised? I will concentrate on the semantic problem and show how new technologies such as a web ontology language can facilitate creating context aware services. An application was implemented using these principles as a proof of concept and to enable some evaluation of this approach. This application has shown that combining semantic processing with SIP call processing is feasible and measurements have demonstrated a highly scalable context aware application for at least simple CPL scripts.I dagens läge är en av de stora utmaningarna att skräddarsy applikationer och tjänster efter kundens begär för att höja användarvänligheten. Fler och fler kunder intresserar sig för tjänster som är kontextuppmärksamma. Jag kommer i mitt arbete att studera detta, mina frågeställningar är huvudsakligen, hur är detta användbart? Vad slags tekniska problem uppstår kring applikationen av detta koncept? Jag kommer att koncentrera mig på semantiska problem och visa hur nya teknologier så som webbontologispråk kan underlätta då man skapar tjänster som är kontextuppmärksamma. Jag kommer även att skapa en applikation där jag använder dessa principer för att visa konceptet och för att underlätta för en utvärdering av detta tillvägagångssätt. Denna applikation samt mätdata visar att det är möjligt att kombinera semantisk bearbetning och SIP anropsbearbetning för att skapa oerhört robusta applikationer, åtminstonde för enkla CPL script, som är hållbara i ett stort omfång av systemstorlekar.
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Pascoe, Jason. "Context-aware software." Thesis, University of Kent, 2001. https://kar.kent.ac.uk/13575/.
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With the advent of PDAs (Personal Digital Assistants), smart phones, and other forms of mobile and ubiquitous computers, our computing resources are increasingly moving off of our desktops and into our everyday lives. However, the software and user interfaces for these devices are generally very similar to that of their desktop counterparts, despite the radically different and dynamic environments that they face. We propose that to better assist their users, such devices should be able to sense, react to, and utilise, the user's current environment or context. That is, they should become context-aware. In this thesis we investigate context-awareness at three levels: user interfaces, applications, and supporting architectures/frameworks. To promote the use of context-awareness, and to aid its deployment in software, we have developed two supporting frameworks. The first is an application-oriented framework called stick-e notes. Based on an electronic version of the common Post-It Note, stick-e notes enable the attachment of any electronic resource (e.g. a text file, movie, Java program, etc.) to any type of context (e.g. location, temperature, time, etc.). The second framework we devised seeks to provide a more universal support for the capture, manipulation, and representation of context information. We call it the Context Information Service (CIS). It fills a similar role in context-aware software development as GUI libraries do in user interface development. Our applications research explored how context-awareness can be exploited in real environments with real users. In particular, we developed a suite of PDA-based context-aware tools for fieldworkers. These were used extensively by a group of ecologists in Africa to record observations of giraffe and rhinos in a remote Kenyan game reserve. These tools also provided the foundations for our HCI work, in which we developed the concept of the Minimal Attention User Interface (MAUI). The aim of the MAUI is to reduce the attention required by the user in operating a device by carefully selecting input/output modes that are harmonious to their tasks and environment. To evaluate our ideas and applications a field study was conducted in which over forty volunteers used our system for data collection activities over the course of a summer season at the Kenyan game reserve. The PDA-based tools were unanimously preferred to the paper-based alternatives, and the context-aware features were cited as particular reasons for preferring them. In summary, this thesis presents two frameworks to support context-aware software, a set of applications demonstrating how context-awareness can be utilised in the ''real world'', and a set of HCI guidelines and principles that help in creating user interfaces that fit to their context of use.
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Rondé-Oustau, Xavier. "Adaptive Context Aware Services." Thesis, KTH, Kommunikationssystem, CoS, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92199.
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Context information is information that describes the user's context. The goal of the Adaptive Context Aware Services (ACAS) project is to enable applications to use context information in order to adapt their behaviour to the user and his environment without requiring the user to manually change/manage parameters. While the concept of linking context aware entities together to form a logical "context network" was introduced earlier in the project, some questions regarding context information discovery and the discovery of context aware entities were previously unanswered. The goal of this thesis was to design and evaluate such a context network allowing entities todiscover each other and exchange information regarding their services and context information. For this purpose, a "Context Entity Registrar" has been developed allowing entities to register, thus they can easily be found by other entities who can query this registrar. During the design of this proposed solution, a special focus has been given to the performance of the registrar, especially how it scales when answering a large number of requests, in order to validate the design's potential as a solution to context aware entity discovery. Measurements have shown that this proposed solution scales well, making it a key element of a context network. Discovery of other entities and of context information play an important role to determine the performances of a context aware implementation. This masters thesis addresses first the issue of the architecture of the context network and then some tests to measure the performances of the proposed solution.Context information är information som beskriver användarens omgivning. Adaptive Context Aware Services (ACAS) projektet har som mål att möjliggöra applikationer att använda kontext information för att anpassa sitt beteende till användaren och dess miljö, utan att kräva att användaren ska sätta eller hantera alla parametrar manuellt. ACAS projektet har tidigare infört konceptet "context network" som förbinder context aware enheter. Det finns dock kvar några obesvarade frågor angående upptäckt av context information och av context aware enheter.Trots att sättet att länka ihop kontextmedvetna enheter för att forma ett logiskt 'kontext nätverk' introducerades tidigare i projektet, finns det kvar några obesvarade frågor angående upptäckt av kontext information och upptäckt av kontextmedvetna enheter. Examensarbetets mål är att utforma och utvärdera ett sådant kontextnätverk som ger enheterna möjlighet att upptäcka varandra och utbyta information om tjänster och context information. Därför utvecklades "Context Entity Registrar" så att enheterna kan registrera sig för att kunna bli upptäckta av andra enheter som kan göra förfrågningar till detta register. Under designen av denna föreslagna lösning har särskild fokus lagts på registrens prestanda, speciellt avseende skalbarhet med avseende på antalet förfrågningar for att validera designens potential som lösning för kontextmedveten upptäckt av enheter. Mätningar har visat att lösningen skalar bra vilket gör kontext registret till ett nyckelelement i ett kontextnätverk. Upptäkten av andra enheter och av kontextinformation har en viktig roll i att bestämma en kontextmedveten implementations prestanda. Detta examensarbete kommer först att behandla kontextnätverkets arkitektur och därefter några testerna för att mäta prestanda i den föreslagna lösningen.
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Diepenbrock, Stefan, Timo Ropinski, and Klaus Hinrichs. "Context-aware volume navigation." University of Münster, Germany, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-92865.
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The trackball metaphor is exploited in many applications where volumetric data needs to be explored. Although it provides an intuitive way to inspect the overall structure of objects of interest, an in-detail inspection can be tedious - or when cavities occur even impossible. Therefore we propose a context-aware navigation technique for the exploration of volumetric data. While navigation techniques for polygonal data require information about the rendered geometry, this strategy is not sufficient in the area of volume rendering. Since rendering parameters, e.g., the transfer function, have a strong influence on the visualized structures, they also affect the features to be explored. To compensate this effect we propose a novel image-based navigation approach for volumetric data. While being intuitive to use, the proposed technique allows the user to perform complex navigation tasks, in particular to get an overview as well as to perform an in-detail inspection without any navigation mode switches. The technique can be easily integrated into raycasting based volume renderers, needs no extra data structures and is independent of the data set as well as the rendering parameters. We will discuss the underlying concepts, explain how to enable the navigation at interactive frame rates using OpenCL, and evaluate its usability as well as its performance.
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Vuković, Maja. "Context aware service composition." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612751.
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Crk, Igor. "Context-Aware Resource Management." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195573.
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The demand for performance and resources that is placed on the system is dictated by the application alone in non-interactive environments, and by a combination of application and user interactions in interactive environments. Understanding user interaction can provide valuable information about which resources will be needed ahead of time. This leads to performance optimizations such as better resource allocations for applications that can utilize a given resource more productively, and transitioning devices to a more appropriate energy performance state before the demand arrives. The challenge is to provide a performance/energy schedule that best matches the task at hand, since keeping the device in one performance level is not energy efficient due to the continually changing demand placed on the device. This dissertation addresses the challenge of designing energy efficient systems by examining the role of user interaction in energy consumption and in providing an energy-performance schedule that adequately accommodates user demand. It is shown that system performance can be tailored to a user's pattern of interaction and it's energy-performance schedule optimized.First, a detailed design of context capture systems in Linux's X-Window System is presented with an evaluation of the associated storage and computation overheads. Due to the overall low complexity of the application window representations, the overheads of computing interaction identifiers and storing a secondary representation of the application interface within the context capture system are likewise low. Additionally, a Microsoft Windows-based context capture system leveraging the Active Accessibility framework is discussed and applied to improving the navigation of cascading pull-down menus.Secondly, this dissertation addresses the application of interaction capture in energy and delay management of Wireless Network Interface Controllers/Cards (WNICs) and hard drives. The Interaction Aware Prediction (IAP) system for WNICs is evaluated showing that the available power modes can be effectively managed to provide energy efficiency while maintaining performance. Similarly, the Interaction Aware Spin-up Prediction (IASP) uses interaction awareness to reduce or eliminate the interactive delays associated with aggressive hard disk energy management.
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Decarli, Nicolò <1985>. "Context-aware wireless networks." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5613/1/decarli_nicolo_tesi.pdf.
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This thesis investigates context-aware wireless networks, capable to adapt their behavior to the context and the application, thanks to the ability of combining communication, sensing and localization. Problems of signals demodulation, parameters estimation and localization are addressed exploiting analytical methods, simulations and experimentation, for the derivation of the fundamental limits, the performance characterization of the proposed schemes and the experimental validation.
Ultrawide-bandwidth (UWB) signals are in certain cases considered and non-coherent receivers, allowing the exploitation of the multipath channel diversity without adopting complex architectures, investigated. Closed-form expressions for the achievable bit error probability of novel proposed architectures are derived.
The problem of time delay estimation (TDE), enabling network localization thanks to ranging measurement, is addressed from a theoretical point of view. New fundamental bounds on TDE are derived in the case the received signal is partially known or unknown at receiver side, as often occurs due to propagation or due to the adoption of low-complexity estimators. Practical estimators, such as energy-based estimators, are revised and their performance compared with the new bounds.
The localization issue is addressed with experimentation for the characterization of cooperative networks. Practical algorithms able to improve the accuracy in non-line-of-sight (NLOS) channel conditions are evaluated on measured data. With the purpose of enhancing the localization coverage in NLOS conditions, non-regenerative relaying techniques for localization are introduced and ad hoc position estimators are devised.
An example of context-aware network is given with the study of the UWB-RFID system for detecting and locating semi-passive tags. In particular a deep investigation involving low-complexity receivers capable to deal with problems of multi-tag interference, synchronization mismatches and clock drift is presented. Finally, theoretical bounds on the localization accuracy of this and others passive localization networks (e.g., radar) are derived, also accounting for different configurations such as in monostatic and multistatic networks.
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Decarli, Nicolò <1985>. "Context-aware wireless networks." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5613/.
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This thesis investigates context-aware wireless networks, capable to adapt their behavior to the context and the application, thanks to the ability of combining communication, sensing and localization. Problems of signals demodulation, parameters estimation and localization are addressed exploiting analytical methods, simulations and experimentation, for the derivation of the fundamental limits, the performance characterization of the proposed schemes and the experimental validation.
Ultrawide-bandwidth (UWB) signals are in certain cases considered and non-coherent receivers, allowing the exploitation of the multipath channel diversity without adopting complex architectures, investigated. Closed-form expressions for the achievable bit error probability of novel proposed architectures are derived.
The problem of time delay estimation (TDE), enabling network localization thanks to ranging measurement, is addressed from a theoretical point of view. New fundamental bounds on TDE are derived in the case the received signal is partially known or unknown at receiver side, as often occurs due to propagation or due to the adoption of low-complexity estimators. Practical estimators, such as energy-based estimators, are revised and their performance compared with the new bounds.
The localization issue is addressed with experimentation for the characterization of cooperative networks. Practical algorithms able to improve the accuracy in non-line-of-sight (NLOS) channel conditions are evaluated on measured data. With the purpose of enhancing the localization coverage in NLOS conditions, non-regenerative relaying techniques for localization are introduced and ad hoc position estimators are devised.
An example of context-aware network is given with the study of the UWB-RFID system for detecting and locating semi-passive tags. In particular a deep investigation involving low-complexity receivers capable to deal with problems of multi-tag interference, synchronization mismatches and clock drift is presented. Finally, theoretical bounds on the localization accuracy of this and others passive localization networks (e.g., radar) are derived, also accounting for different configurations such as in monostatic and multistatic networks.
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Herrera, Ordenes Alexis. "Implementacion de Context-Aware Aspects en Reflex y Evaluación en una Aplicación Context-Aware." Tesis, Universidad de Chile, 2007. http://repositorio.uchile.cl/handle/2250/104750.
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El objetivo general de este trabajo consiste en extender el framework Reflex para soportar context-aware aspects. Este nuevo framework permitirá integrar sensores de contexto implementados con WildCAT para el desarrollo de una aplicación modelo que requiera aspectos context-aware.
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Alharthi, Raneem. "Context–Aware Stress Prediction System." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34486.
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Stress is now recognized as one of the major causes of physical and psychological illness. It is known as a reaction to surrounding environmental threats and the best way to manage it is to understand its triggers. Although people continuously react to their surrounding environments, they sometimes are not aware that certain elements in their environment are considered to be stressors.
Based on this fact, researchers have recently proposed context-aware stress management systems. Most of the proposed systems use context data to provide real time stress monitoring and visualization, along with intervention techniques. However, these interventions are limited to the second and tertiary stages and very little attention has been given to the primary stage.
In this thesis, we introduce a system called CASP. The system’s objective is to provide stress status predictions based on a user’s current contextual data. Therefore, a detection method is developed using heart rate variability (HRV) as a stress indicator to deliver personalized context-aware stress reports. Based on the predicted status, the system provides users with stress interventions at an early stage in order to help avoid and/or eliminate the occurrence of stress. Our evaluation results show that the CASP system is able to predict the stress status of a user with an averaged accuracy of 78.23% through our limited activity, when compare to a stress status measured using physiological signals. Moreover, it provides prediction models that adapt to the changing nature of both the user’s stress status and the surrounding environment.
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Yu, Hong Qing. "Context-aware automatic service selection." Thesis, University of Leicester, 2009. http://hdl.handle.net/2381/7764.
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Service-Oriented Architecture (SOA) is a paradigm for developing next generation distributed systems. SOA introduces an opportunity to build dynamically configurable distributed systems by invoking suitable services at runtime, which makes the systems being more flexible to be integrated and easily to be reused. With fast growing numbers of offered services, automatically identifying suitable services becomes a crucial issue. A new and interesting research direction is to select a service which is not only suitable in general but also suitable towards a particular requester's needs and services context at runtime. This dissertation proposes an approach for supporting automatic context-aware service selection and composition in a dynamic environment. The main challenges are: (1) specifying context information in a machine usable form; (2) developing a service selection method which can choose the adequate services by use the context information; (3) introducing context-awareness into the service composition process. To address the challenges, we employ Semantic Web technology for modelling context information and service capabilities to automatically generate service selection criteria at runtime. Meanwhile, a Type-based Logic Scoring Preference Extended (TLE) service selection method is developed to adequately and dynamically evaluate and aggregate the context-aware criteria. In addition, we introduce the composition context and a Backward Composition Context based Service Selection algorithm (BCCbSS) for composing suitable services on the y in a fault-tolerant manner. Furthermore, this dissertation describes the design and implementation of the method and algorithm. Experimental evaluation results demonstrate that the TLE method and BCCbSS algorithm provide an efficient and scalable solution to deal with the context-aware service selection problem both in single service selection and composition scenarios. Our research results make a further step to develop highly automated and dynamically adaptive systems in the future.
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Nelson, Giles John. "Context-aware and location systems." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624875.
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Smaaberg, Simen Fivelstad. "Context-Aware Group Recommendation Systems." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for datateknikk og informasjonsvitenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-27328.
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For a group of friends going to a concert or a festival, finding concerts that everyone is happy with can be challenging as everyone have their own preferences and wishes when it comes to music.In this thesis, a prototype of a group recommendation system for concerts is presented to solve this issue. The prototype is context sensitive; it takes a user's location and time into account when giving recommendations. The prototype implements three algorithms to recommend concerts by taking advantage of what users have listened to before: a collaborative filtering algorithm (k-Nearest Neighbor), a Matrix Factorization algorithm, and a Hybrid approach of these two.The thesis was written following the Design Science Research paradigm. The thesis covers the design and implementation of the prototype in addition to a brief review of the state of the art of the recommendation systems literature. The usability of the prototype was evaluated using the System Usability Scale, and a user centered evaluation was performed to evaluate the quality of recommendations. The results from the usability evaluation shows that users generally were satisfied with the usability of the prototype. The results from the Quality Evaluation shows that the k-Nearest Neighbor and Hybrid approach produces satisfactory results whereas the Matrix Factorization implementation is lagging a bit behind. The users testing the prototype were generally satisfied with the quality of recommendations, however further evaluation is needed to draw any final conclusions.
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Contreas, Ricardo. "Context aware Web-service monitoring." Thesis, City University London, 2013. http://openaccess.city.ac.uk/2723/.
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Monitoring the correct behaviour of a service-based system is a necessity and a key challenge in Service Oriented Computing. Several efforts have been directed towards the development of approaches dealing with the monitoring activity of service-based systems. However, these approaches are in general not suitable when dealing with modifications in service-based systems. Furthermore, existing monitoring approaches do not take into consideration the context of the users and how this context may affect the monitor activity. Consequently, a holistic monitor approach, capable of dealing with the dynamic nature of service-based systems and of taking into consideration the user context, would be highly desirable. In this thesis we present a monitor adaptation framework capable of dealing with changes in a service-based system and different types of users interacting with it. More specifically, the framework obtains a set of monitor rules, necessary to verify the correct behaviour of a service-based system, for a particular user. Moreover, the monitor rules verifying the behaviour of a service-based system relate to properties of the context types defined for a user. The main contributions of our work include the general characterisation of a user interacting with a service-based system and the generation of suitable monitor rules.The proposed framework can be applied to any service composition without the need of further modifications. Our work complements previous research carried on in the area of web service monitoring. More specifically, our work generates a set of suitable monitor rules - related to the user context - which are deployed in a run-time monitor component. Our framework has been tested and validated in several cases considering different scenarios.
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Heaney, Séan F. "Context aware body area networks." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680115.
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Body Area Networks (BAN) are unique in that the large-scale mobility of users alongside the complexity of body movements allows the network itself to travel across a diverse range of operating domains or even to enter new and unknown environments. These body movements along with the diversity of these unknown environments can create unique transmission channels. This network mobility is unlike node mobility in that sensed changes in inter-network interference level may be used to identify opportunities for intelligent inter-networking, for example, by merging or splitting from other networks, thus providing an extra degree of freedom. As the BAN network travels it will cause and be subject to inter-network interference but it also has the opportunity to sense and interact with a range of other networks. Using a series of carefully controlled measurements of the mesh interconnectivity both within and between ambulatory BANs as well as a stationary desk-based network, this thesis presents an investigation of context aware body area network (CABAN) interference detection at the physical layer. This thesis, also gives consideration to the co-existence of multiple co-located BAN users and the complex interaction of body-shadowing, user movement as well as the multi:"path environment itself and its impact on channel conditions. The final aspect of the thesis investigates the interaction between physical layer characteristics and packet error rate (PER) at the data link layer as two independent BANs operating in CSMA networks as they could merge and split
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Alharbi, Mafawez. "Context-aware Personal Learning Environment." Thesis, De Montfort University, 2014. http://hdl.handle.net/2086/10102.
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Research is now shifting away from Virtual Learning Environments (VLEs) and towards the use of the Personal Learning Environment (PLE). A review of a number of PLE architectures are presented in the literature, and while they convey well the concept of a PLE, nevertheless they could best be described as high-level architectures, (sometimes referred to as frameworks in the literature), which focus mainly the functionality of PLEs. In particular, there is little published which gives a detailed designed of a PLE architecture. Moreover, the published work focuses largely on the support for lifelong learning and formal / informal learning; these are two of the main limitations of VLEs. However, this study argues that unexplored potential remains, as there is scope for PLEs to cover more areas. To the best of our knowledge, none of the existing PLE architectures have context-aware systems embedded within their architecture. There is no intelligence in these architectures to filter the e-resources and to predict the user need. In addition, the current PLE architectures are not dynamic; it cannot adopt the user current situation. The user of the current PLE architectures receives too much e-resource. The architecture proposed in this research incorporates a context-aware engine. Thus there is intelligence built into the architecture and thus the PLE system is automatically responsive to the context information. There are three types of sensors in any context-aware system (physical, virtual and logical), and these are the elements of the system that gather the context information. In this research, the emphasis will be on virtual sensors which gather the information from virtual space; virtual space here includes any systems which produce information as a set of results. Thus, the context-aware architecture and the implementation of the context-aware engine are major contributions of the work.
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Miranda, Luís Henrique Fernandes Moura. "Context-aware multi-factor authentication." Master's thesis, Faculdade de Ciências e Tecnologia, 2009. http://hdl.handle.net/10362/4111.
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Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia InformáticaAuthentication systems, as available today, are inappropriate for the requirements of ubiquitous, heterogeneous and large scale distributed systems. Some important limitations are: (i) the use of weak or rigid authentication factors as principal’s identity proofs, (ii) non flexibility to combine different authentication modes for dynamic and context-aware interaction criteria, (iii) not being extensible models to integrate new or emergent pervasive authentication factors and (iv) difficulty to manage the coexistence of multi-factor authentication proofs in a unified single sign-on solution. The objective of this dissertation is the design, implementation and experimental evaluation of a platform supporting multi-factor authentication services, as a contribution to overcome the above limitations. The devised platform will provide a uniform and flexible authentication base for multi-factor authentication requirements and context-aware authentication modes for ubiquitous applications and services. The main contribution is focused on the design and implementation of an extensible authentication framework model, integrating classic as well as new pervasive authentication factors that can be composed for different context-aware dynamic requirements. Flexibility criteria are addressed by the establishment of a unified authentication back-end, supporting authentication modes as defined processes and rules expressed in a SAML based declarative markup language. The authentication base supports an extended single sign-on system that can be dynamically tailored for multi-factor authentication policies, considering large scale distributed applications and according with ubiquitous interaction needs.
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Demeter, Nora. "Context aware voice user interface." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22417.
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In this thesis I address the topic of a non-visual approach for interaction on mobile,as an alternative to their existing visual displays in situations where hands free usageof the device is preferred. The current technology will be examined through existingwork with special attention to its limitations, which user groups are currently using anysort of speech recognition or voice command functions and look at in which scenariosare these the most used and most desired. Then I will examine through interviews whypeople trust or distrust voice interactions and how they feel about the possibilities andlimitations of the technology at hand, how individual users use this currently and wheredo they see the technology in the future. After this I will develop an alternative voiceinteraction concept, and validate it through a set of workshops.
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Gu, Boxuan. "Context-Aware Malicious Code Detection." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354523604.
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Kalousek, Jiří. "Context-Aware P2P Network Construction." Thesis, Linnéuniversitetet, Institutionen för datavetenskap (DV), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-65460.
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With growing number of devices connected to the network, there is a greater need for use of Peer-to-Peer (P2P) networks and distributed P2P protocols.Devices participating in the P2P network do not usually need to use any central server that links up connections. It has many advantages but it needs to use so-called overlay network that consists of protocols used for traffic routing and decision making. Protocols used in today’s P2P networks are mostly not considerate of particular participating nodes and all the nodes in the network are usually equal. This can have negative impacts on network performance. In order to avoid or reduce some unwanted negative impacts, it would be advantageous if the overlay network could route traffic and make decisions according to context information like battery levels or connection speeds. This work reviews a few popular P2P overlay networks and based on that it introduces an improvement of one of them – Chord. The structure of the improved version of the Chord protocol called Context-Aware Chord is described. Then results of the evaluation are presented. With a use of the improved protocol, nodes can participate longer in the network and throughput of lookup messages is improved.
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Devlic, Alisa. "Context-addressed communication dispatch." Licentiate thesis, KTH, Communication Systems, CoS, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10282.
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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)
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Ognenoski, Ognen. "Content-aware and context-aware adaptive video streaming over HTTP." Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/37874/.
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Adaptive HTTP video streaming techniques are rapidly becoming the main method for video delivery over the Internet. From a conceptual viewpoint, adaptive HTTP video streaming systems enable adaptation of the video quality according to network conditions (link-awareness), content characteristics (content-awareness), user preferences (user-awareness) or device capabilities (device awareness). Proprietary adaptive HTTP video streaming platforms from Apple, Adobe and Microsoft preceded the completion of a standard for adaptive HTTP video streaming, i.e., the MPEG-DASH standard. The dissertation presents modeling approaches, experiments, simulations and subjective tests tightly related to adaptive HTTP video streaming with particular emphasis on the MPEG-DASH standard. Different case studies are investigated through novel models based on analytical and simulation approaches. In particular, adaptive HTTP video streaming over Long Term Evolution (LTE) networks, over cloud infrastructure, and streaming of medical videos are investigated and the relevant benefits and drawbacks of using adaptive HTTP video streaming for these cases are highlighted. Further, mathematical tools and concepts are used to acquire quantifiable knowledge related to the HTTP/TCP communication protocol stack and to investigate dependencies between adaptive HTTP video streaming parameters and the underlying Quality of Service (QoS) and Quality of Experience (QoE). Additionally, a novel method and model for QoE assessment are proposed, derived in a specific experimental setup. A more general setup is then considered and a QoE metric is derived. The QoE metric expresses the users' quality for adaptive HTTP video streaming by taking into consideration rebuffering, video quality and content-related parameters. In the end, a novel analytical model that captures the user's perception of quality via the experienced delay during streaming navigation is derived. The contributions in this dissertation and the relevant conclusions are obtained by simulations, experimental demo setups, subjective tests and analytical modeling.
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Houyou, Amine Mohamed. "Context-aware mobility : a distributed approach to context management /." kostenfrei, 2009. http://www.opus-bayern.de/uni-passau/volltexte/2010/1797/.
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Sama, M. "Context-driven methodologies for context-aware and adaptive systems." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1322993/.
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Applications which are both context-aware and adapting, enhance users’ experience by anticipating their need in relation with their environment and adapt their behavior according to environmental changes. Being by definition both context-aware and adaptive these applications suffer both from faults related to their context-awareness and to their adaptive nature plus from a novel variety of faults originated by the combination of the two. This research work analyzes, classifies, detects, and reports faults belonging to this novel class aiming to improve the robustness of these Context-Aware Adaptive Applications (CAAAs). To better understand the peculiar dynamics driving the CAAAs adaptation mechanism a general high-level architectural model has been designed. This architectural model clearly depicts the stream of information coming from sensors and being computed all the way to the adaptation mechanism. The model identifies a stack of common components representing increasing abstractions of the context and their general interconnections. Known faults involving context data can be re-examined according to this architecture and can be classified in terms of the component in which they are happening and in terms of their abstraction from the environment. Resulting from this classification is a CAAA-oriented fault taxonomy. Our architectural model also underlines that there is a common evolutionary path for CAAAs and shows the importance of the adaptation logic. Indeed most of the adaptation failures are caused by invalid interpretations of the context by the adaptation logic. To prevent such faults we defined a model, the Adaptation Finite-State Machine (A-FSM), describing how the application adapts in response to changes in the context. The A-FSM model is a powerful instrument which allows developers to focus in those context-aware and adaptive aspects in which faults reside. In this model we have identified a set of patterns of faults representing the most common faults in this application domain. Such faults are represented as violation of given properties in the A-FSM. We have created four techniques to detect such faults. Our proposed algorithms are based on three different technologies: enumerative, symbolic and goal planning. Such techniques compensate each other. We have evaluated them by comparing them to each other using both crafted models and models extracted from existing commercial and free applications. In the evaluation we observe the validity, the readability of the reported faults, the scalability and their behavior in limited memory environments. We conclude this Thesis by suggesting possible extensions.
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Nilsson, Joackim. "Dynamic Personal Networks for Location-Based Applications : Within MediaSense." Thesis, Mid Sweden University, Department of Information Technology and Media, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-11782.
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As the development of context aware applications has evolved, there has been a corresponding increase in need for more sophisticated system. The aim for this thesis is the development of a dynamical P2P network system which is based on locations. The P2P network is self organizing and in a lightweight format. Modern technical solutions including AGPS have facilitated the work associated with the ability to position users and modern mathematical solutions such as spherical trigonometry provides the P2P system with the necessary accuracy even for short distances. The P2P system works on different Java platforms including JSE, JME and Android. Unfortunately the 3G network distributor has not yet solved a NAT traversal problem, which means that the P2P network self organization and architecture has only been proved by means of simulations. Another problem is that certain mathematical formulas are required for the spherical trigonometry and the limitation for JME is that it is unable to handle inverse trigonometry. However, the Android and JSE versions can form a correct P2P network, under the condition that the Android device uses a WIFI connection point outside the 3G distributor network system. This thesis reports the successful testing of the locations-based P2P network.
MediaSense
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Nicolini, Andrea. "Context-Aware Computing e Tecnologie Wearable." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10556/.
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Quest' ultimo ventennio ha visto una vera e propria rivoluzione dei dispositivi, partendo dal computer desktop, passando ai laptop fino ad arrivare agli smartphone. Oggi giorno invece si parla di computer indossabili, i dispositivi stanno diventando sempre più piccoli e integrati in oggetti di moda come possono essere degli orologi, occhiali e orecchini.Questi sono connessi in rete con migliaia di dispositivi e con computer più grandi, con i quali, gli utenti nel corso della giornata interagiscono continuamente senza nemmeno rendersene conto scambiandosi migliaia di piccole informazioni: quando si cammina per strada, in centro città quando si fanno compere, quando si è in casa a guardare la TV. Questo ha portato quindi alla nascita di una nuova tipologia di sistemi, in risposta ai cambiamenti portati da questa rivoluzione, i così detti "Sistemi Context-Aware".Il context di un utente può essere descritto come la relazione che vi è tra i suoi dispositivi elettronici, e l' ambiente che lo circonda, a seconda di dove si trova esso dovrà dare delle risposte opportune, e compiere quindi autonomamente certe azioni, tal volta ad insaputa dell' utente. Le applicazioni che usano quindi questo sistema, vengono continuamente messe a conoscenza dei cambiamenti che vengono apportati all' ambiente circostante, regolandosi e reagendo di conseguenza in autonomia. Ad esempio, il nostro dispositivo scopre tramite la rete, la presenza di un amico nelle vicinanze, mentre stiamo passeggiano per strada, allora potrebbe inviarci un messaggio mostrandoci chi è, e dove si trova, con il tragitto da percorrere per raggiungerlo.
Le migliaia di informazioni che vengono quindi scambiate in rete andranno a creare “un ambiente intelligente”, con il quale gli utenti interagiscono inviando informazioni sul proprio conto, senza nemmeno accorgersene, in modo da avere una risposta personalizzata, da parte dell' ambiente.
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Ergüt, Salih. "Context-aware computing for wireless networks." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3402341.
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Thesis (Ph. D.)--University of California, San Diego, 2010.Title from first page of PDF file (viewed May 14, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Bhatia, Nupur. "Policy Management in Context-Aware Networks." Thesis, KTH, Kommunikationssystem, CoS, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92015.
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The Ambient Network (AN) Project is part of the European Commission’s 6th Framework Programme and aims to enable cooperation between heterogeneous networks, using current and future wireless technologies, minimising the effort of mobile users to gain access to the services that they are interested in - irrespective of their location or the network they are currently using. Because of the highly mobile nature of users and a demand for instant and dynamic access to services, these networks have to be composed ‘on the fly’ without any pre-configurations. The use of context information in AN can remove the need for pre-configuration of networks, hence making them autonomic. However, a concern exists that the free and uncontrolled dissemination of context information could breech the privacy of the participants. It is extremely important to address these privacy issues in order to control who has access to what context information. This control can be achieved through the use of well defined policies. This creates a requirement for a framework in the ContextWare architecture for protecting context information. This masters thesis project is part of an effort to create a policy based infrastructure for authorisation of access to network context information within the AN. The thesis investigates, models, and designs an architecture for a policy management system based on OASIS XACML, that creates an extension to the architecture for management of context information in the AN. In addition to a policy management architecture within an AN, a policy management architecture for composing ANs is also created. To facilitate the transfer of requests and policies, the thesis creates a Policy Management Protocol. The designed architecture was then implemented to create a proof of concept. The designed architecture and protocol were evaluated by running tests on the prototype. The measurements from the tests are analysed and presented in this thesis. The analysis of the experimental data indicates that a policy management system is both feasible and practical. The results show that the delay overhead caused by introducing policy management in a distributed context provisioning system, ranges from 1.7% in a system without load to 6% in a worst case scenario. The throughput of the policy management system is 15 requests per second under load.Ambient Network är ett EU-finansierat project inom det 6:e ramprogrammet.Projektets mål är att möjliggöra samarbete mellan heterogena nätverk, som använderbåde dagens men även framtidens trådlösa teknologier, för att minimeraslutanvändarens insats för att nå den tjänst de är intresserade av – oberoende av platseller vilket nätverk de använder. På grund av den stora delen av mobila användaresom kräver omedelbar och dynamisk tillgång till tjänster måste dessa nätverk gåsamman ’on the fly’ utan tidigare konfigurering.Användningen av context information i Ambient Networks kan elmininera behovet avförkonfigurering av nätverk, följaktligen blir de då autonoma. Dock, ett problem somuppkommer med detta är att den fria och okontrollerade spridningen av contextinformation bryter integriteten för deltagarna. Det är väldigt viktigt att ta itu med dettaproblem för att kunna kontrollera vilka som har tillgång till vilken contextinformation. Den här kontrollen kan uppnås genom väldefinierade policies. Dettaskapar ett behov av ett ramverk inom ContextWare arkitekturen för att skydda dentillgängliga context informationen. Den här uppsatsen är en del i ansträngningen att skapa en policy baserad infrastrukturför attestering av tillgång till context information inom Ambient Networks. Uppsatsenundersöker och designar en arkitektur för ett policy handhavande system som ärbaserat på OASIS XACML, den bygger vidare på arkitekturen för handhavande avcontext information i Ambient Networks. Utöver policy hantering inom ett ambientnetwork skapas också policy hantering mellan ambient networks när de förenas. Denframtagna arkitekturen är därefter implementerad för att visa på konceptets hållbarhet. En sammanslagning av två policy handhavande system när två nätverk slås ihop ärbehandlat endast i teorin, det är inte implementerat. Designen utvärderas genom att köra test på den implementerade versionen ochdärefter analysera och visa resultaten i rapporten. Dessa test innehåller mätningar avfördröjningen av en enda begäran samt flera, responstiden i ett system med policyhanteringjämfört med utan samt prestandan i ett policy-hanteringssystem med en litenmängd policies jämfört med en större mängd policies.
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Alalshuhai, Ahmed. "Requirements engineering of context-aware applications." Thesis, De Montfort University, 2015. http://hdl.handle.net/2086/12487.
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Context-aware computing envisions a new generation of smart applications that have the ability to perpetually sense the user’s context and use these data to make adaptation decision in response to changes in the user’s context so as to provide timely and personalized services anytime and anywhere. Unlike the traditional distribution systems where the network topology is fixed and wired, context-aware computing systems are mostly based on wireless communication due to the mobility of the network nodes; hence the network topology is not fixed but changes dynamically in an unpredictable manner as nodes join and the leave network, in addition to the fact that wireless communication is unstable. These factors make the design and development of context-aware computing systems much more challenging, as the system requirements change depending on the context of use. The Unified Modelling Language (UML) is a graphical language commonly used to specify, visualize, construct, and document the artefacts of software-intensive systems. However, UML is an all-purpose modelling language and does not have notations to distinguish context-awareness requirements from other system requirements. This is critical for the specification, visualization, construction and documentation of context-aware computing systems because context-awareness requirements are highly important in these systems. This thesis proposes an extension of UML diagrams to cater for the specification, visualization, construction and documentation of context-aware computing systems where new notations are introduced to model context-awareness requirements distinctively from other system requirements. The contributions of this work can be summarized as follows: (i) A context-aware use case diagram is a new notion which merges into a single diagram the traditional use case diagram (that describes the functions of an application) and the use context diagram, which specifies the context information upon which the behaviours of these functions depend. (ii) A Novel notion known as a context-aware activity diagram is presented, which extends the traditional UML activity diagrams to enable the representation of context objects, context constraints and adaptation activities. Context constraints express conditions upon context object attributes that trigger adaptation activities; adaptation activities are activities that must be performed in response to specific changes in the system’s context. (iii) A novel notion known as the context-aware class diagram is presented, which extends the traditional UML class diagrams to enable the representation of context information that affect the behaviours of a class. A new relationship, called utilisation, between a UML class and a context class is used to model context objects; meaning that the behaviours of the UML class depend upon the context information represented by the context class. Hence a context-aware class diagram is a rich and expressive language that distinctively depicts both the structure of classes and that of the contexts upon which they depend. The pragmatics of the proposed approach are demonstrated using two real-world case studies.
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Panidis, Panteleimon. "Middleware for Context-Aware Opportunistic Networks." Thesis, KTH, Kommunikationssystem, CoS, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92261.
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Mobile devices such as palmtops and cell phones are continuously increasing in capabilities and popularity. At the same time, due to their decreasing price they are becoming more and more attractive and available to the average customer. This has lead to the development of many new applications for such portable electronic devices. Mobile devices tend to have increasing local resources in terms of memory/storage and CPU [2]. Despite these improvements in hardware attributes, there are still limitations that characterize these portable devices and which have not improved as quickly as the increase of the local computational power. These limitations mostly concern the network resources and battery power that are both still rather poor. Thus the main barriers for mobile nodes are network resources and limiting the power consumption of the device itself. Today, wireless networks provide limited reliability and less bandwidth than fixed networks. Moreover, all mobile nodes are highly energy dependent as they use batteries with a limited capacity. Additionally, roaming is a feature that increasingly must be supported for such wireless devices, as their physical portability leads to users to use them even as they move about. This may require the utilization of different wireless networks while the node is on the move. Therefore, for all the above reasons there is a demand for the development of intelligent mechanisms and techniques for optimizing the management of these limited resources, while exploiting the local resources, thus providing users with the best possible performance within the available resources. At the present, there are operating systems, such as the Symbian OS [22], specially designed for supporting advanced features in mobile computing. However, there is still development to be done. Moreover, although there are many new applications for mobile computing, they are not yet sophisticated enough to cope with changes in the wireless environment, these changes occur due to the node’s change in context. This creates a gap that should be filled by software between the applications and the operating system; this is frequently called middleware. This middleware provides a collaborative partnership between the operating system and the applications, assisting and making both more sophisticated, in terms of scheduling and managing traffic in a wireless environment. The focus of this project is how to utilize such middleware to best serve the needs of the mobile user.Mobila enheter som handdatorer och mobiltelefoner har kontinuerligt utökat sina användningsområden och popularitet. Samtidigt har de i och med det fallande priset blivit mer och mer attraktiva och tillgängliga för den allmänna marknaden. Detta har lett till utveckling av nya tillämpningar för sådana portabla elektriska enheter. Mobila enheter tenderar att få ökade lokala resurser som exempelvis större minne och CPU [2]. Fastän en förbättring av dessa hårdvaror har gjorts så karaktäriseras enheterna av begränsningar som inte har utvecklats i lika rask takt som de lokala resurserna. Dessa begränsningar handlar till större delen om nätverks resurser och tillförsel av energi via batteri, som båda fortfarande är relativt dåliga. De huvudsakliga barriärerna för de mobila noderna är alltså nätverks resurser och enheternas energikonsumtion. I dagens läge förser de trådlösa närverken en begränsad pålitlighet och lägre bandbredd än de fasta nätverken. Alla mobila noder är även väldigt energiberoende eftersom de använder sig av ett energibegränsat batteri. Förutom detta så är roaming en aspekt som måste öka för sådana trådlösa enheter eftersom deras transportabla egenskaper medför att användaren kan använda sig av enhetens funktioner även vid mobilitet. Detta leder till att det behövs tillgång till olika trådlösa nätverk i och med att enheten omplaceras. På grund av alla dessa orsaker som beskrivits ovan finns det en efterfrågan på utveckling av intelligenta mekanismer och tekniker för användningsoptimering av dessa begränsande faktorer, samtidigt som man maximerar de lokala resurserna och på detta sätt ger användaren bästa möjliga prestanda inom det tillgängliga området. I dagens läge finns det operativ system, som Symbian OS [22], speciellt designade för att stödja avancerade drag inom mobile computing. Det finns däremot utrymme för utveckling av dessa och fastän det finns många nya tillämpningar för mobile computing så är de inte tillräckligt sofistikerade för att klara av ett smidigt byte mellan trådlösa nätverk när noderna omplaceras. Detta medför ett glapp som borde åtgärdas med mjukvara kallad mellanvara, ett program som förmedlar arbetsuppgifter mellan användarnas tillämpningar och datornätets resurser. Mellanvaran gör att operativ systemet samarbetar med användarens tillämpningar och gör att hela systemet blir mer sofistikerat i termer av trafik hantering i den trådlösa miljön. Tyngdpunkten i detta projekt ligger i hur man ska utnyttja sådan mellanvara för att optimera systemet i de mobila enheterna utifrån användarens behov.
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Marmasse, Natalia 1962. "comMotion : a context-aware communication system." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/61841.
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Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 1999.Includes bibliographical references (p. 83-84).
How many times have you gone to the grocery store but left your shopping list on the refrigerator door? Wouldn't it be more efficient to have a reminder to buy groceries and the shopping list delivered to you when you were in the vicinity of the store? How many times have you suddenly thought of something you must do or have just had a great idea that you want to write down, or record, for future reference? Wouldn't it be useful to record that thought and be reminded of it when in the relevant place and time? Information delivery utopia would be to receive the exact amount of data we need (no more, no less), when and where we need it, and in a gratifying format, for example, in a pleasant voice or well-structured text. Although we are still far away from this goal, a partial solution to the information overload is to create systems which deliver timely information when the user is in the relevant context. This thesis describes comMotion, a context-aware communication system for a mobile or wearable computing platform. A behaviour-learning agent automatically learns the salient locations in the user's life. Once these places have been determined, location specific to-do lists, electronic Post-it notes or reminders, and subscription requested information can be delivered to the user at the right place and time. The user interacts with the system through a visual and/or speech interface.
by Natalia Marmasse.
S.M.
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Stoyanov, Stanimir. "Context-aware and adaptable eLearning systems." Thesis, De Montfort University, 2012. http://hdl.handle.net/2086/9882.
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This thesis proposed solutions to some shortcomings to current eLearning architectures. The proposed DeLC architecture supports context-aware and adaptable provision of eLearning services and electronic content. The architecture is fully distributed and integrates service-oriented development with agent technology. Central to this architecture is that a node is our unit of computation (known as eLearning node) which can have purely service-oriented architecture, agent-oriented architecture or mixed architecture. Three eLeaerning Nodes have been implemented in order to demonstrate the vitality of the DeLC concept. The Mobile eLearning Node uses a three-level communication network, called InfoStations network, supporting mobile service provision. The services, displayed on this node, are to be aware of its context, gather required learning material and adapted to the learner request. This is supported trough a multi-layered hybrid (service- and agent-oriented) architecture whose kernel is implemented as middleware. For testing of the middleware a simulation environment has been developed. In addition, the DeLC development approach is proposed. The second eLearning node has been implemented as Education Portal. The architecture of this node is poorly service-oriented and it adopts a client-server architecture. In the education portal, there are incorporated education services and system services, called engines. The electronic content is kept in Digital Libraries. Furthermore, in order to facilitate content creators in DeLC, the environment Selbo2 was developed. The environment allows for creating new content, editing available content, as well as generating educational units out of preexisting standardized elements. In the last two years, the portal is used in actual education at the Faculty of Mathematics and Informatics, University of Plovdiv. The third eLearning node, known as Agent Village, exhibits a purely agent-oriented architecture. The purpose of this node is to provide intelligent assistance to the services deployed on the Education Pportal. Currently, two kinds of assistants are implemented in the node - eTesting Assistants and Refactoring eLearning Environment (ReLE). A more complex architecture, known as Education Cluster, is presented in this thesis as well. The Education Cluster incorporates two eLearning nodes, namely the Education Portal and the Agent Village. eLearning services and intelligent agents interact in the cluster.
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Alotaibi, Hind. "Context-aware and secure workflow systems." Thesis, De Montfort University, 2012. http://hdl.handle.net/2086/8052.
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Businesses do evolve. Their evolution necessitates the re-engineering of their existing "business processes”, with the objectives of reducing costs, delivering services on time, and enhancing their profitability in a competitive market. This is generally true and particularly in domains such as manufacturing, pharmaceuticals and education). The central objective of workflow technologies is to separate business policies (which normally are encoded in business logics) from the underlying business applications. Such a separation is desirable as it improves the evolution of business processes and, more often than not, facilitates the re-engineering at the organisation level without the need to detail knowledge or analyses of the application themselves. Workflow systems are currently used by many organisations with a wide range of interests and specialisations in many domains. These include, but not limited to, office automation, finance and banking sector, health-care, art, telecommunications, manufacturing and education. We take the view that a workflow is a set of "activities”, each performs a piece of functionality within a given "context” and may be constrained by some security requirements. These activities are coordinated to collectively achieve a required business objective. The specification of such coordination is presented as a set of "execution constraints” which include parallelisation (concurrency/distribution), serialisation, restriction, alternation, compensation and so on. Activities within workflows could be carried out by humans, various software based application programs, or processing entities according to the organisational rules, such as meeting deadlines or performance improvement. Workflow execution can involve a large number of different participants, services and devices which may cross the boundaries of various organisations and accessing variety of data. This raises the importance of _ context variations and context-awareness and _ security (e.g. access control and privacy). The specification of precise rules, which prevent unauthorised participants from executing sensitive tasks and also to prevent tasks from accessing unauthorised services or (commercially) sensitive information, are crucially important. For example, medical scenarios will require that: _ only authorised doctors are permitted to perform certain tasks, _ a patient medical records are not allowed to be accessed by anyone without the patient consent and _ that only specific machines are used to perform given tasks at a given time. If a workflow execution cannot guarantee these requirements, then the flow will be rejected. Furthermore, features/characteristics of security requirement are both temporal- and/or event-related. However, most of the existing models are of a static nature – for example, it is hard, if not impossible, to express security requirements which are: _ time-dependent (e.g. A customer is allowed to be overdrawn by 100 pounds only up-to the first week of every month. _ event-dependent (e.g. A bank account can only be manipulated by its owner unless there is a change in the law or after six months of his/her death). Currently, there is no commonly accepted model for secure and context-aware workflows or even a common agreement on which features a workflow security model should support. We have developed a novel approach to design, analyse and validate workflows. The approach has the following components: = A modelling/design language (known as CS-Flow). The language has the following features: – support concurrency; – context and context awareness are first-class citizens; – supports mobility as activities can move from one context to another; – has the ability to express timing constrains: delay, deadlines, priority and schedulability; – allows the expressibility of security policies (e.g. access control and privacy) without the need for extra linguistic complexities; and – enjoy sound formal semantics that allows us to animate designs and compare various designs. = An approach known as communication-closed layer is developed, that allows us to serialise a highly distributed workflow to produce a semantically equivalent quasi-sequential flow which is easier to understand and analyse. Such re-structuring, gives us a mechanism to design fault-tolerant workflows as layers are atomic activities and various existing forward and backward error recovery techniques can be deployed. = Provide a reduction semantics to CS-Flow that allows us to build a tool support to animate a specifications and designs. This has been evaluated on a Health care scenario, namely the Context Aware Ward (CAW) system. Health care provides huge amounts of business workflows, which will benefit from workflow adaptation and support through pervasive computing systems. The evaluation takes two complementary strands: – provide CS-Flow’s models and specifications and – formal verification of time-critical component of a workflow.
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Smith, Jeremiah. "Learning in mobile context-aware applications." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/30633.
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This thesis explores and proposes solutions to the challenges in deploying context-aware systems that make decisions or take actions based on the predictions of a machine learner over long periods of time. In particular, this work focuses on mobile context-aware applications which are intrinsically personal, requiring a specific solution for each individual that takes into account user preferences and changes in user behaviour as time passes. While there is an abundance of research on mobile context-aware applications which employ machine learning, most does not address the three core challenges required to be deployable over indefinite periods of time. Namely, (1) user-friendly and longitudinal collection and labelling of data, (2) measuring a user's experienced performance and (3) adaptation to changes in a user's behaviour, also known as concept drift. This thesis addresses these challenges by introducing (1) an infer-and-confirm data collection strategy which passively collects data and infers data labels using the user's natural response to target events, (2) a weighted accuracy measure Aw as the objective function for underlying machine learners in mobile context-aware applications and (3) two training instance selection algorithms, Training Grid and Training Clusters which only forget data points in areas of the data space where newer evidence is available, moving away from the traditional time window based techniques. We also propose a new way of measuring concept drift indicating which type of concept drift adaption strategy is likely to be beneficial for any given dataset. This thesis also shows the extent to which the requirements posed by the use of machine learning in deployable mobile context-aware applications influences its overall design by evaluating a mobile context-aware application prototype called RingLearn, which was developed to mitigate disruptive incoming calls. Finally, we benchmark our training instance selection algorithms over 8 data corpuses including the RingLearn corpus collected over 16 weeks and the Device Analyzer corpus which logs several years of smartphone usage for a large set of users. Results show that our algorithms perform at least as well as state-of-the-art solutions and many times significantly better with performance delta ranging from -0.2% to +11.3% compared to the best existing solutions over our experiments.
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Shah, Harshal. "A context-aware approach to healthcare." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10144828.
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Context-aware systems are a component of a ubiquitous computing or pervasive computing environment. Three important aspects of context include the following: where you are, who you are with, and what resources are nearby. Although location is a primary capability, location-aware does not necessarily capture information of interest that are mobile or changing. Context-aware, in contrast, is used more generally to include nearby people, devices, lighting, noise level, network availability, and even a social situation, such as whether someone is with a family member or a friend from school.
The purpose of this project is to introduce a healthcare application named ‘Care Taker’ that facilitates a longitudinal study in which data is gathered from a user’s smartphone over a period of time using a context aware application. This data is then analyzed to give a user actionable health related recommendations.
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Rangel, Vacas Inmaculada. "Context Aware and Adaptive Mobile Audio." Thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92291.
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Today a large percentage of the population uses a handheld (either a mobile phone or a PDA) a laptop computer, or some other computing device. As this penetration increases, the user wants to take as great an advantage of these devices as possible. It is for that reason that communication is demanded almost everywhere. Simply having continuous access to the network is no longer sufficient thus context awareness and easy accessibility are becoming more and more relevant. The idea of this masters thesis is to explore these ideas building on the prior work of Maria José Parajón Domínguez. The devices used for this study will be an HP iPAQ h5550 and a laptop. A client-server application, whose components will be explained in detail in further sections, was designed to study some factors that may be taken into account when trying to satisfy the users´ demands as stated above. One of these factors could be, for example, what are the effects of having a personal voice interface on the traffic to and from the user’s mobile device. The aim of this voice interface will be to provide more freedom to the user and also satisfy the demand for greater accessibility and facilitate mobile usage, not only for the common user, but also for handicapped people. Regarding the user’s desire to always have connectivity everywhere, we wish to examine the effects on the traffic to and from the user’s handheld, when exploiting significant local storage. Also related to the requirements on current devices to be always and everywhere connected and the huge amount of resources that this entails, it will be of interest to study the possibility of exchanging personalized CODECs (in the extreme case exchanging voice synthesis modules) and how this might affect traffic to and from the user’s mobile device. This last method could potentially greatly reducing both the demands on the communication links and the cost of this connectivity. With all these ideas in mind, this thesis aims to research an area that is nowadays continuously attracting new users and the goal is to find solutions to the demands that have resulted for these trends.Användningen av portabla elektroniska apparater så som mobiltelefoner, handdatorer med mera är nu för tiden vida utbrett. Ju fler apparater som används desto större blir efterfrågan efter mobila tjänster för dessa. Som ett resultat ökar behovet av goda kommunikationslösningar, ofta mer komplexa än endast kontinuerlig dataåtkomst. Syftet med detta examensarbete är att fortsätta att utforska de idéer som Maria José Parajón Domínguez presenterat. För att utföra detta kommer en HP iPAQ h5550 och en bärbar dator att användas. En klient-server applikation kommer att tas fram för att undersöka några faktorer som påverkar kommunikationslösningarna. Ett exempel på en sådan faktor skulle kunna vara effekten av att ha ett personligt röstgränssnitt för trafiken. Syftet med detta gränssnitt skulle vara att erbjuda användaren större frihet och flexibilitet för sitt mobilanvändande, oavsett om användaren lider av något handikapp eller ej. Försök kommer även att göras med att lagra mycket data lokalt på användarens apparat, detta i ett försök att minska datatrafiken då många apparater kräver ständig och intensiv datakommunikation. Det är även av intresse att studera möjligheten av utbyte av personliga algoritmer, så kallade CODEC, och hur dessa skulle kunna påverka datatrafiken till och från den portabla apparaten. Det genomgående syftet för alla dessa faktorer är att sänka belastningen på de kommunikationslänkar som utnyttjas. Målet med denna studie är att undersöka några sätt att möta den ökade belastning på kommunikationssystemen som väntas om trenden för mobilt användande ökar.
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Jurgovsky, Johannes. "Context-aware credit card fraud detection." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI109.
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La fraude par carte de crédit est devenue un problème majeur dans le secteur des paiements électroniques. Dans cette thèse, nous étudions la détection de fraude basée sur les données transactionnelles et abordons plusieurs de ces défis complexes en utilisant des méthodes d'apprentissage automatique visant à identifier les transactions frauduleuses qui ont été émises illégitimement au nom du titulaire légitime de la carte. En particulier, nous explorons plusieurs moyens d’exploiter les informations contextuelles au-delà des attributs de base d’une transaction, notamment au niveau de la transaction, au niveau de la séquence et au niveau de l'utilisateur. Au niveau des transactions, nous cherchons à identifier les transactions frauduleuses qui présentent des caractéristiques distinctes des transactions authentiques. Nous avons mené une étude empirique de l’influence du déséquilibre des classes et des horizons de prévision sur la performance d d'un classifieur de type random forest. Nous augmentons les transactions avec des attributs supplémentaires extraits de sources de connaissances externes et montrons que des informations sur les pays et les événements du calendrier améliorent les performances de classification, particulièrement pour les transactions ayant lieu sur le Web. Au niveau de la séquence, nous cherchons à détecter les fraudes qui sont difficiles à identifier en elles-mêmes, mais particulières en ce qui concerne la séquence à court terme dans laquelle elles apparaissent. Nous utilisons un réseau de neurone récurrent (LSTM) pour modéliser la séquence de transactions. Nos résultats suggèrent que la modélisation basée sur des LSTM est une stratégie prometteuse pour caractériser des séquences de transactions ayant lieu en face à face, mais elle n’est pas adéquate pour les transactions ayant lieu sur le Web. Au niveau de l'utilisateur, nous travaillons sur une stratégie existante d'agrégation d'attributs et proposons un concept flexible nous permettant de calculer de nombreux attributs au moyen d'une syntaxe simple. Nous fournissons une implémentation basée sur CUDA pour pour accélerer le temps de calcul de deux ordres de grandeur. Notre étude de sélection des attributs révèle que les agrégats extraits de séquences de transactions des utilisateurs sont plus utiles que ceux extraits des séquences de marchands. De plus, nous découvrons plusieurs ensembles d'attributs candidats avec des performances équivalentes à celles des agrégats fabriqués manuellement tout en étant très différents en termes de structure. En ce qui concerne les travaux futurs, nous évoquons des méthodes d'apprentissage artificiel simples et transparentes pour la détection des fraudes par carte de crédit et nous esquissons une modélisation simple axée sur l'utilisateurCredit card fraud has emerged as major problem in the electronic payment sector. In this thesis, we study data-driven fraud detection and address several of its intricate challenges by means of machine learning methods with the goal to identify fraudulent transactions that have been issued illegitimately on behalf of the rightful card owner. In particular, we explore several means to leverage contextual information beyond a transaction's basic attributes on the transaction level, sequence level and user level. On the transaction level, we aim to identify fraudulent transactions which, in terms of their attribute values, are globally distinguishable from genuine transactions. We provide an empirical study of the influence of class imbalance and forecasting horizons on the classification performance of a random forest classifier. We augment transactions with additional features extracted from external knowledge sources and show that external information about countries and calendar events improves classification performance most noticeably on card-not-present transaction. On the sequence level, we aim to detect frauds that are inconspicuous in the background of all transactions but peculiar with respect to the short-term sequence they appear in. We use a Long Short-term Memory network (LSTM) for modeling the sequential succession of transactions. Our results suggest that LSTM-based modeling is a promising strategy for characterizing sequences of card-present transactions but it is not adequate for card-not-present transactions. On the user level, we elaborate on feature aggregations and propose a flexible concept allowing us define numerous features by means of a simple syntax. We provide a CUDA-based implementation for the computationally expensive extraction with a speed-up of two orders of magnitude. Our feature selection study reveals that aggregates extracted from users' transaction sequences are more useful than those extracted from merchant sequences. Moreover, we discover multiple sets of candidate features with equivalent performance as manually engineered aggregates while being vastly different in terms of their structure. Regarding future work, we motivate the usage of simple and transparent machine learning methods for credit card fraud detection and we sketch a simple user-focused modeling approach
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Lima, Christopher Viana. "Context-aware framework for collaborative applications." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15921.
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Doutoramento em Engenharia InformáticaFuture pervasive environments will take into consideration not only individual user’s interest, but also social relationships. In this way, pervasive communities can lead the user to participate beyond traditional pervasive spaces, enabling the cooperation among groups and taking into account not only individual interests, but also the collective and social context. Social applications in CSCW (Computer Supported Cooperative Work) field represent new challenges and possibilities in terms of use of social context information for adaptability in pervasive environments. In particular, the research describes the approach in the design and development of a context.aware framework for collaborative applications (CAFCA), utilizing user’s context social information for proactive adaptations in pervasive environments. In order to validate the proposed framework an evaluation was conducted with a group of users based on enterprise scenario. The analysis enabled to verify the impact of the framework in terms of functionality and efficiency in real-world conditions. The main contribution of this thesis was to provide a context-aware framework to support collaborative applications in pervasive environments. The research focused on providing an innovative socio-technical approach to exploit collaboration in pervasive communities. Finally, the main results reside in social matching capabilities for session formation, communication and coordinations of groupware for collaborative activities.
O futuro dos ambientes pervasivos irá levar em consideração não só os interesses individuais dos utilizadores, mas também as relações sociais. Desta forma, a participação em comunidades pode levar o utilizador para além da experiência em espaços tradicionais pervasivos, permitindo a cooperação entre grupos e tendo em conta não só os intresses individuais, mas também o contexto coletivo e social. Aplicações sociais na área de CSCW (Computer Supported Cooperative Work) representam novos desafios e possibilidades em termos do uso da informação social de contexto para a adaptação e personalização em computação pervasiva. Esta tese explora o potencial da utilização consciente do contexto e das informações sociais em aplicações CSCW, a fim de apoiar a colaboração em ambientes pervasivos. Em particular, a investigação descreve a abordagem do design e desenvolvimento de um framework consciente do contexto para aplicações colaborativas (CAFCA), utilizando-se das informações de contexto e sociais dos utilizadores para adaptações proactivas em ambientes pervasivos. A fim de validar o framework proposto, uma avaliação foi realizada com um grupo de utilizadores, com base num cenário empresarial. A análise permitiu verificar o impacto do framework em termos de funcionalidade e eficiência em condições do mundo real. A principal contribuição deste trabalho foi desenvolver um framework contexto-aware para suportar aplicações de colaboração em ambientes pervasivos. A investigação centrou-se em uma abordagem sociotécnica inovadora de explorar a colaboração em comunidades. Os principais objetivos residem na capacidade social para formação de sessões, a comunicação e coordenação de groupware para atividades colaborativas.
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Bolat, Murat. "Instrumentation tool for context-aware optimization." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 64 p, 2009. http://proquest.umi.com/pqdweb?did=1885467641&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Gligorijevic, Jelena. "Context-aware Learning from Partial Observations." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/484799.
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Computer and Information SciencePh.D.
The Big Data revolution brought an increasing availability of data sets of unprecedented scales, enabling researchers in machine learning and data mining communities to escalate in learning from such data and providing data-driven insights, decisions, and predictions. However, on their journey, they are faced with numerous challenges, including dealing with missing observations while learning from such data or making predictions on previously unobserved or rare (“tail”) examples, which are present in a large span of domains including climate, medical, social networks, consumer, or computational advertising domains. In this thesis, we address this important problem and propose tools for handling partially observed or completely unobserved data by exploiting information from its context. Here, we assume that the context is available in the form of a network or sequence structure, or as additional information to point-informative data examples. First, we propose two structured regression methods for dealing with missing values in partially observed temporal attributed graphs, based on the Gaussian Conditional Random Fields (GCRF) model, which draw power from the network/graph structure (context) of the unobserved instances. Marginalized Gaussian Conditional Random Fields (m-GCRF) model is designed for dealing with missing response variable value (labels) in graph nodes, whereas Deep Feature Learning GCRF is able to deal with missing values in explanatory variables while learning feature representation jointly with learning complex interactions of nodes in a graph and together with the overall GCRF objective. Next, we consider unsupervised and supervised shallow and deep neural models for monetizing web search. We focus on two sponsored search tasks here: (i) query-to-ad matching, where we propose novel shallow neural embedding model worLd2vec with improved local query context (location) utilization and (ii) click-through-rate prediction for ads and queries, where Deeply Supervised Semantic Match model is introduced for dealing with unobserved and tail queries click-through-rate prediction problem, while jointly learning the semantic embeddings of a query and an ad, as well as their corresponding click-through-rate. Finally, we propose a deep learning approach for ranking investigators based on their expected enrollment performance on new clinical trials, that learns from both, investigator and trial-related heterogeneous (structured and free-text) data sources, and is applicable to matching investigators to new trials from partial observations, and for recruitment of experienced investigators, as well as new investigators with no previous experience in enrolling patients in clinical trials. Experimental evaluation of the proposed methods on a number of synthetic and diverse real-world data sets shows surpassing performance over their alternatives.
Temple University--Theses
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Chu, Justin. "CONTEXT-AWARE DEBUGGING FOR CONCURRENT PROGRAMS." UKnowledge, 2017. https://uknowledge.uky.edu/cs_etds/61.
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Concurrency faults are difficult to reproduce and localize because they usually occur under specific inputs and thread interleavings. Most existing fault localization techniques focus on sequential programs but fail to identify faulty memory access patterns across threads, which are usually the root causes of concurrency faults. Moreover, existing techniques for sequential programs cannot be adapted to identify faulty paths in concurrent programs. While concurrency fault localization techniques have been proposed to analyze passing and failing executions obtained from running a set of test cases to identify faulty access patterns, they primarily focus on using statistical analysis. We present a novel approach to fault localization using feature selection techniques from machine learning. Our insight is that the concurrency access patterns obtained from a large volume of coverage data generally constitute high dimensional data sets, yet existing statistical analysis techniques for fault localization are usually applied to low dimensional data sets. Each additional failing or passing run can provide more diverse information, which can help localize faulty concurrency access patterns in code. The patterns with maximum feature diversity information can point to the most suspicious pattern. We then apply data mining technique and identify the interleaving patterns that are occurred most frequently and provide the possible faulty paths. We also evaluate the effectiveness of fault localization using test suites generated from different test adequacy criteria. We have evaluated Cadeco on 10 real-world multi-threaded Java applications. Results indicate that Cadeco outperforms state-of-the-art approaches for localizing concurrency faults.
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Johansson, Dan. "A context-aware application mobility approach." Licentiate thesis, Luleå tekniska universitet, Datavetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25713.
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Over the last two decades, mobile computing has gone from being a mere vision to becoming a reality, ubiquitously present in our everyday lives. There are different types of mobility, from user and terminal mobility, to mobility of services and sessions. This thesis is mainly about application mobility { the ability for an application to migrate between different host devices during its execution. The aim of this thesis work is to explore and advance the area of application mobility. The thesis approaches this goal through focusing on three research issues: Architectural considerations for application mobility; Context-awareness support and application adaptability; and Concept exploration.The contributions of this thesis include the identification of requirements for application mobility and a proposal for a decentralized, global scale architecture for application mobility, building on the peer-to-peer paradigm. Several prototypes of systems allowing application mobility are deployed, manifesting concepts such as decentralized system layout, context-awareness, context quality and global scope. Evaluations are both quantitative and qualitative. Other contributions of this thesis are the design and evaluation of a framework building on cloud and peer-to-peer technology to enable mobile sessions and an exploration of the concept of application mobility.Godkänd; 2012; 20121019 (dandan); LICENTIATSEMINARIUM Ämne: Mobila system/Mobile Systems Examinator: Professor Christer Åhlund, Institutionen för system- och rymdteknik, Luleå tekniska universitet Diskutant: Professor Christian Becker, University of Mannheim, Germany Tid: Måndag den 26 november 2012 kl 10.00 Plats: Hörsal A, campus Skellefteå, Luleå tekniska universitet
Sense Smart City, MOSA - mobil och öppen tjänste-access, NIMO - Nordic Interaction and Mobility Research Platform
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MARTIRE, FRANCESCA. "Context-aware services for mobile devices." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/518.
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La Context-awareness, è un insieme di features tecniche che permette di offrire una vasta gamma di servizi dove le informazioni “seguono” gli utenti. Tali servizi promettono di fornire le informazioni di cui l’utente necessita nel momento giusto, al posto giusto e nel modo più semplice, veloce e opportuno. La prima parte della mia attività di ricerca si è focalizzata su un sottoinsieme di aspetti associati alla Context Awareness. Il lavoro si colloca in un progetto di ricerca finanziato dalla Comunità Europea: il progetto SIMPLICITY. Simplicity propone una generalizzazione del concetto di “portabilità”, permettendo agli utenti di muoversi senza vincoli tra differenti applicazioni distribuite e diversi servizi, utilizzando tecnologie di rete ed apparecchiature eterogenee. A partire da questi obiettivi la mia ricerca si è concentrata proprio sul Profilo d’utente prendendo come punto di partenza il Generic User Profile proposto dal 3GPP(GUP). Il mio lavoro si è focalizzato su un ripensamento dell’ architettura proposta dal 3GPP e la struttura che alla fine ne deriva ricopre ed estende tale modello. La ricerca si è successivamente spostata sul contenuto del profilo utente e quindi sui dati che tale profilo doveva contenere. Nella tesi è presentato anche il concetto di Simplicity Device(SD), un dispositivo portatile, che permette agli utenti di “portare” da un terminale ad un altro la propria identità digitale, i propri dati personali e le proprie preferenze. L’utilizzo congiunto di un profilo d'utente personale e di un dispositivo hardware (SD), permette di ottenere una configurazione automatica, trasparente, e personalizzata, di terminali, dispositivi, e servizi.
Nei sistemi in cui “le informazioni devono seguire gli utenti”, ecco che ci si trova a parlare di localizzazione, ossia di individuazione della posizione dell’utente in movimento. In tale prospettiva, nella seconda parte di questa tesi, il problema della localizzazione e i cosiddetti “Location Based Services” (LBS) hanno rivestito notevole interesse. Anche in questo caso l’attività si inquadra in un altro progetto di ricerca Europeo: il progetto SMS (Simple Mobile Services). In particolare i servizi SMS promettono di fornire all’utente mobile non servizi e informazioni generiche ma contestualizzate e quindi basate, tra l’altro, sulla posizione e area geografica in cui si trova nel momento in cui richiede le informazioni e i servizi stessi. Nella tesi è descritto lo studio ed implementazione di un’architettura di supporto per servizi Location Based nuovi o già esistenti. Essa è strutturata su più livelli e le interfacce realizzate consentono l’accesso semplice alle funzionalità dei livelli sottostanti. In particolare esse sono state progettate come strumenti che sollevino gli sviluppatori dai problemi relativi all’acquisizione del dato di posizione e che allo stesso tempo nascondano i dettagli delle tecniche che permettono la localizzazione stessa. Il sistema è slegato dalla particolare tecnologia di localizzazione utilizzata e ingloba in sé più tecnologie di localizzazione essendo in grado di scegliere quale utilizzare a seconda del contesto. Parallelamente l’architettura è stata pensata in modo tale da poter essere utilizzata anche in situazioni in cui non è possibile determinare la posizione corrente di un utente. L’architettura e le location API implementate, costituiscono un sistema per lo sviluppo di applicazioni Location Based per scenari sia Indoor che Outdoor. La soluzione proposta è altresì in grado di gestire in modo trasparente e senza interrompere la continuità del servizio la transizione tra spazi Indoor e Outdoor. Nella tesi sono descritti e analizzati i dettagli implementativi di ogni livello dell’architettura. Sono stati realizzati due moduli software che forniscono servizi di navigazione e localizzazione sia in spazi aperti che chiusi. I due Navigatori realizzati offrono le stesse interfacce grazie a un contenitore generico dell’informazione di posizione che entrambe utilizzano. I dettagli della definizione, implementazione e originale utilizzo di tale fondamentale oggetto, chiamato “Position object” sono altresì oggetto di questa trattazione.“Context-awareness lets computing technology to provide services to people at any time, any where, with any media but also specifically to communicate the right thing at the right time and in the right way”. Within the research field of context-aware services, researchers from industry and academia have been working on solutions for this problem for the last decade. In the first part of my research work I focused on a subset of the research field of context aware-services. The work has been performed in the context of the SIMPLICITY project. The personalization concept is based on a user profile which realizes a common underlying information model for all the elements of the Simplicity architecture. In this perspective the first part of this dissertation focuses on my specification and development of the Simplicity User Profile (SUP) to provide highly personalized context-aware services with reduced interactional complexity for the end-user. I started from the work carried out in 3GPP on the GUP but I extended and improved that approach. In this dissertation I also present the concept of the Simplicity Device (SD) which is an enhanced mobile phone that stores and handles personal information, user preferences and policies. The SD, by the simple act of “plugging” it into a terminal, becomes the “virtual” identity of the end-user. It allows the enforcement of user-personalized mechanisms to exploit service fruition, to drive automatic adaptation to terminal capabilities, and to facilitate service adaptation to various network technologies and related capabilities. The SUP, the SD together with a brokerage framework simplify the process of using current and future “services” providing a user-friendly solution. To best meet the mobile user’s current and continuously changing context, location-aware capabilities represent an important issues to be addressed. Hence the second part of this thesis consider Location-Awareness and Location Based Service(LBS). The work was performed in the framework of an another IST Project, named Simple Mobile Services (SMS). SMS services will target specific locations visited by specific classes of mobile user with specific needs. In this perspective my research activity was devoted to define, project and implement a Localization and Navigation architecture that, in many ways, enable the simple creation and development of new context-sensitive services or supply existing applications with location awareness. The driving idea was to develop simple to use interfaces leveraging the developers and the users the complexities related to the acquisition of a position information as well as hiding the particulars of the positioning technologies employed. Moreover the overall architecture is conceived to support situations in which determining the exact position of a mobile terminal is not a strict requirement, but it is enough to identify the terminal position within a radius or inside an area (e.g., rooms indoor, or zones outdoor). The software architecture also makes a combined use of indoor and outdoor location-sensing technologies being able to solve localization problems independently from the environment and the location technology in use. It also realizes a transparent and automatic switch mechanism from indoor to outdoor (and vice versa) situations without breaking the continuity of the service usage. To prove the feasibility of the entire architecture a prototypical implementation has been developed using J2ME CLDC on Java enabled phones. Both the indoor and outdoor implemented navigation applications provide the same interfaces, thanks to the general purpose definition of the same position information container used for both of them. The definition and implementation process of this object, named Position object, is here presented.
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MISSAOUI, SONDESS. "Context-Aware Approaches to Mobile Search." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/195639.
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Nel dominio del turismo mobile, turisti nella ricerca di servizi correlati ai viaggi in base alla loro specifica situazione contestuale. In questa tesi, in particolare, ci concentriamo sulle due dimensioni principali del contesto attuale dell'utente: (i) il contesto spazio-temporale e (ii) il contesto cognitivo, cioè rappresentato dall'attualità dell'utente interessi.Con il miglioramento delle tecnologie context-aware, una grande quantità di fattori contestuali (tempo, luogo, ora, umore o compagno) possono essere raccolti automaticamente. Tuttavia, non tutti sono ugualmente importanti per fornire raccomandazioni efficaci. quindi, è imperativo identificare e raccogliere solo quei fattori che influenzano veramente le preferenze dell'utente e migliorare l'efficacia del sistema. Per questo motivo, come primo obiettivo di questa tesi, abbiamo proposto metodo efficace per la raccolta e la modellazione. Il nostro metodo, basato in una procedura di acquisizione del contesto selettivo, considera un fattore contestuale come pertinente se migliora la precisione del sistema. Abbiamo ampiamente esplorato il metodo proposto nel contesto del Web mobile ricerca. Un altro problema che è stato considerato in questa tesi approcci per la consulenza personalizzata sul Web (registri di ricerca, dati click-through) per definire gli interessi dell'utente. Questo tipo di le informazioni possono essere influenzate dal rumore, mentre fonti attendibili modellano gli interessi attuali dell'utente sono assolutamente necessari per avere raccomandazioni precise. Per questo motivo, in questa tesi noi focalizzato sull'estrazione degli interessi attuali dell'utente dai contenuti generati dagli utenti on-line. Più specificamente, abbiamo proposto un profilo utente multistrato, in cui ogni livello rappresenta il preferenze dell'utente in relazione a una distinta categoria di servizi correlati ai viaggi. Abbiamo usato il linguaggio statistico. Questo modello ci consente di descrivere la distribuzione di probabilità delle parole all'interno della lingua di un utente su cui si basa social media in forma di recensioni testuali. La natura espressiva del profilo utente è stata esplorata per i servizi relativi ai viaggi. Inoltre, sulla base dei fattori contestuali considerati, sia spazio-temporali che cognitivi, abbiamo proposto un approccio basato sul contesto e sul contenuto per le raccomandazioni di viaggio. Questo approccio sfrutta i fattori contestuali e gli interessi attuali dell'utente rappresentati dal suo profilo utente. Innanzitutto, un pre-filtro contestuale viene applicato per stimare la rilevanza dei servizi relativi ai viaggi rispetto a quelli spazio-temporali dell'utente contesto. Quindi, un nuovo approcio di filtraggio basato sul contenuto viene svolto in aggiunta i servizi di viaggio selezionati. L'approcio di filtraggio basato sul contenuto considera sia il profilo dell'utente che come modellato in questa tesi - e il profilo dei servizi relativi ai viaggi, e confrontarli per mezzo di misure di similarità adeguate per raccomandare all'utente i servizi top-k che sono di più simile agli interessi dell'utente. Il profilo utente e l'approccio basato sul contesto e sul contenuto offerto in questa tesi sono stati sviluppati come ulteriore contributo di questa tesi. In particolare, abbiamo progettato un sistema di raccomandazione mobile di facile utilizzo, ovvero LOOKER, che fa leva sui consigli di viaggio su un cellulare utente che sta visitando una nuova città. Inoltre, LOOKER affronta il miglioramento dell'utente esperienza attraverso una conoscenza attiva degli utenti. Il l'applicazione è stata implementata come Rich Mobile Application, all'interno del progetto PASRI finanziato dall'Unione Europea. Conduciamo uno studio dell'utente che consente di misurare la soddisfazione e l'attitudine dell'utente il nostro sistema. I risultati dimostrano che il nostro approccio basato sul contesto e sul contenuto può migliorare l'esperienza dell'utente.In the mobile tourism domain, travel recommendation is a crucial task that aims to assist tourists in finding relevant travel-related services based on their specific contextual situation. In this thesis, in particular, we focus on two main dimensions of the user’s current context: (i) the spatio-temporal context, and (ii) the cognitive context, i.e., represented by the user’s topical interests. With the improvement of context-aware technologies, a big amount of contextual factors can be automatically gathered. However, not all of them are equally important for providing effective recommendations. Hence, it is imperative to identify and collect only those factors that truly affect the user’s preferences and improve the system effectiveness. For this reason, as a first aim of this thesis, we proposed an effective method for gathering and modeling relevant contextual factors. Our method, based on a selective context acquisition procedure, deems a contextual factor as relevant if it improves the system accuracy. We extensively explored the proposed method in the context of mobile Web search. Another issue that has been considered in this thesis concerns the fact that traditional approaches for personalized recommendation make use of a variety of user’s historical behaviors on the Web to define the user’s interests. This kind of information may be affected by noise, while reliable sources to model the user’s topical interests are absolutely necessary to have accurate recommendations. For this reason, in this thesis we focused on the extraction of the user’s topical interests from on-line User-Generated Content. More specifically, we proposed a multi-layer user profile, where each layer represents the user’s preferences with respect to a distinct travel-related service category. We used statistical language models to model the different layers. This model enables us to depict the probability distribution of words within a user’s language that s/he employs over social media in form of textual reviews. The expressive nature of the user profile was explored for the travel-related services recommendation in a restricted geographical area. Furthermore, based on the considered contextual factors, both spatio-temporal and cognitive, we proposed a context-aware and content-based approach for travel recommendation. This approach jointly leverages contextual factors and the user’s topical interests represented by her/his user profile to recommend travel-related services. First, a contextual pre-filtering is applied to estimate the relevance of travel-related services with respect to the user’s spatiotemporal context. Then, a novel Content-Based Filtering approach is performed on top of the selected travel-related services. The CBF approach considers both the user’s profile – as modeled in this thesis – and the travel-related services’ profile, and compare them by means of suitable similarity measures in order to recommend to the user the top-k services that are more similar to the user’s interests. The user profile and the context-aware and content-based recommendation approach proposed in this thesis have been employed in a mobile application that has been developed as a further contribution of this thesis. In particular, we designed a mobile user-friendly recommender system, namely LOOKER, which leverages travel recommendations to a mobile user who is visiting a new city. Moreover, LOOKER addresses the improvement of the user experience through an active learning of users preferences and interactive recommendation. The application was implemented as a Rich Mobile Application, within the PASRI project funded by European Union. We conducted a user study that allows to measure the user’s satisfaction and attitude towards our system. The results demonstrate that our context-aware and content-based approach can increase the recommendation accuracy while improve the user’s experience.
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Al-Sammarraie, Mohammed. "Policy-based approach for context-aware systems." Thesis, De Montfort University, 2011. http://hdl.handle.net/2086/5386.
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Pervasive (ubiquitous) computing is a new paradigm where the computers are submerged into the background of the everyday life. One important aspect of pervasive systems is context-awareness. Context-aware systems are those that can adapt their behaviours according to the current context. Context-aware applications are being integrated into our everyday activity aspects such as: health care, smart homes and transportations. There exist a wide range of context-aware applications such as: mobile phones, learning systems, smart vehicles. Some context-aware systems are critical since the consequence of failing to identify a given context may be catastrophic. For example, an auto-pilot system is a critical context-aware system; it senses the humidity, clouds, wind speed and accordingly adjusts the altitude, throttle and other parameters. Being a critical context-aware system has to be provably correct. Policy-based approaches has been used in many applications but not in context-aware systems. In this research, we want to discover the anatomy (i.e. architecture, structure and operational behaviour) of policy-based management as applied to context-aware systems, and how policies are managed within such a dynamic system. We propose a novel computational model and its formalisation is presented using the Calculus of Context-aware Ambients (CCA). CCA has been proposed as a suitable mathematical notation to model mobile and context-aware systems. We decided to use CCA due to three reasons: (i) in CCA, mobility and context-awareness are primitive constructs and are treated as first-class citizens; (ii) properties of a system can be formally analysed; (iii) CCA specifications are executable, and thus, leading to rapid prototyping and early validation of the system properties. We, then show how policies can be expressed in CCA. For illustration, the specification of the event-condition-action (ECA) conceptual policy model is modelled in CCA in a natural fashion. We also propose a policy-based architecture for context-aware systems, showing its different components, and how they interact. Furthermore, we give the specification of the policy enforcement mechanism used in our proposed architecture in CCA. To evaluate our approach, a real-world case study of an infostation-based mobile learning (mLearning) system is chosen. This mLearning system is deployed across a university campus to enable mobile users to access mobile services (mServices) represented by course materials (lectures, tests and tutorials) and communication services (intelligent message notification and VoIP). Users can access the mServices through their mobile devices (Hand-set phones, PDAs and laptops) regardless of their device type or location within a university campus. We have specified the mLearning system in CCA (i.e. specification based on policies of the mServices), afterwards, the specification is simulated using the CCA interpreter tool. We have developed an animation tool specially designed for the mLearning system. The animation tool provides graphical representation of the CCA processes. In terms of safety and liveness, some important properties of the mLearning system have been validated as a proof of concept.
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Santos, Marcelo Mendonça dos. "Road Detection in Traffic Analysis: A Context-aware Approach." Escola Politécnica /Instituto de Matemática, 2014. http://repositorio.ufba.br/ri/handle/ri/23039.
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Correctly identifying the road area on an image is a crucial task for many traffic analyses based on surveillance cameras and computer vision. Despite that, most of the systems do not provide this functionality in an automatic fashion; instead, the road area needs to be annotated by tedious and inefficient manual processes. This situation results in further inconveniences when one deals with a lot of cameras, demanding considerable effort to setup the system. Besides, since traffic analysis is an outdoor activity, cameras are exposed to disturbances due to natural events (e.g., wind, rain and bird strikes), which may require recurrent system reconfiguration. Although there are some solutions intended to provide automatic road detection, they are not capable of dealing with common situations in urban context, such as poorly-structured roads or occlusions due to objects stopped in the scene. Moreover in many cases they are restricted to straight-shaped roads (commonly freeways or highways), so that automatic road detection cannot be provided in most of the traffic scenarios. In order to cope with this problem, we propose a new approach for road detection. Our method is based on a set of innovative solutions, each of them intended to address specific problems related to the detection task. In this sense, a context-aware background modeling method has been developed, which extracts contextual information from the scene in order to produce background models more robust to occlusions. From this point, segmentation is performed to extract the shape of each object in the image; this is accomplished by means of a superpixel method specially designed for road segmentation, which allows for detection of roads with any shape. For each extracted segment we then compute a set of features, the goal of which is supporting a decision tree-based classifier in the task of assigning the objects as being road or non-road. The formulation of our method — a road detection carried out by a combination of multiple features — makes it able to deal with situations where the road is not easily distinguishable from other objects in the image, as when the road is poorly-structured. A thorough evaluation has indicated promising results in favour of this method. Quantitatively, the results point to 75% of accuracy, 90% of precision and 82% of recall over challenging traffic videos caught in non-controlled conditions. Qualitatively, resulting images demonstrate the potential of the method to perform road detection in different situations, in many cases obtaining quasi-perfect results.
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Daruwala, Yohann. "A Constructive Memory Architecture for Context Awareness." Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/2250.
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Context-aware computing is a mobile computing paradigm in which applications can discover, use, and take advantage of contextual information, such as the location, tasks and preferences of the user, in order to adapt their behaviour in response to changing operating environments and user requirements. A problem that arises is the inability to respond to contextual information that cannot be classified into any known context. Many context-aware applications require all discovered contextual information to exactly match a type of context, otherwise the application will not react responsively. The ability to learn and recall contexts based on the contextual information discovered has not been very well addressed by previous context-aware applications and research. The aim of this thesis is to develop a component middleware technology for mobile computing devices for the discovery and capture of contextual information, using the situated reasoning concept of constructive memory. The research contribution of this thesis lies in developing a modified architecture for context-aware systems, using a constructive memory model as a way to learn and recall contexts from previous experiences and application interactions. Using a constructive memory model, previous experiences can be induced to construct potential contexts, given a small amount of learning and interaction. The learning process is able to map the many variations of contextual information currently discovered by the user with a predicted type of context based on what the application has stored and seen previously. It only requires a small amount of contextual information to predict a context, something common context-aware systems lack, as they require all information before a type of context is assigned. Additionally, some mechanism to reason about the contextual information being discovered from past application interactions will be beneficial to induce contexts for future experiences.
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Daruwala, Yohann. "A Constructive Memory Architecture for Context Awareness." University of Sydney, 2008. http://hdl.handle.net/2123/2250.
Full textAbstract:
Master of Philosophy (Architecture)Context-aware computing is a mobile computing paradigm in which applications can discover, use, and take advantage of contextual information, such as the location, tasks and preferences of the user, in order to adapt their behaviour in response to changing operating environments and user requirements. A problem that arises is the inability to respond to contextual information that cannot be classified into any known context. Many context-aware applications require all discovered contextual information to exactly match a type of context, otherwise the application will not react responsively. The ability to learn and recall contexts based on the contextual information discovered has not been very well addressed by previous context-aware applications and research. The aim of this thesis is to develop a component middleware technology for mobile computing devices for the discovery and capture of contextual information, using the situated reasoning concept of constructive memory. The research contribution of this thesis lies in developing a modified architecture for context-aware systems, using a constructive memory model as a way to learn and recall contexts from previous experiences and application interactions. Using a constructive memory model, previous experiences can be induced to construct potential contexts, given a small amount of learning and interaction. The learning process is able to map the many variations of contextual information currently discovered by the user with a predicted type of context based on what the application has stored and seen previously. It only requires a small amount of contextual information to predict a context, something common context-aware systems lack, as they require all information before a type of context is assigned. Additionally, some mechanism to reason about the contextual information being discovered from past application interactions will be beneficial to induce contexts for future experiences.
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Balasubramaniam, Sasitharan. "Context-aware vertical handovers for pervasive systems /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18525.pdf.
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Kalaiah, Aravind. "Visual data representation using context-aware Samples." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2465.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Computer Science. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.