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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improving the Adaptive Context Views and Evaluate Real-Time Performance

Ali, Majid January 2013 (has links)
The versatility and dimension of smart phone applications is   increasing at magnificent rate and getting more and more advanced in a level that could solve complicated real time tasks. One of the important factors for such advancement has been the powerful sensors embedded on a Smartphone devices and sensory networks. Moreover, Context and Context-awareness would have remained a myth without the advent of sensors. The objective of this thesis has been to contribute to the research work carried out under the MediaSense project. Accordingly, the ultimate purpose of the thesis has been to evaluate and study the feasibility of the adaptive context view proposed in MediaSense Platform. In precise words, the thesis has done three core tasks. Firstly, the theoretical presentation of related works and the significance of the research question have been discussed through various social applications. Secondly, a proof-of-concept application has been developed to simulate what has been proposed in the research work. Finally, Android application has been designed and implemented in order to evaluate and study the techniques presented in a practical scenario. Moreover, in the android application known as SundsvallBIGBuddies, we have used the extensions designed for the existing MediaSense platform. The impact of using Android app relaying on a continuous stream of context data has been presented using graphs and tables.  In order to study the impact we used smart phone and tablets from Samsung.
2

Autonomic Context Management System for Pervasive Computing

Peizhao Hu Unknown Date (has links)
Stepping into the 21st century, we see more and more evidence of the growing trend towards the amalgamation of cyberspace and the physical world. This trend emerged as computing technologies moved o_ desktops and migrated into aspects of our lives through their ubiquitous presence in the physical world. As these technologies become enmeshed in our daily routines, they begin to `disappear' from our awareness and cease to be thought of as technologies and simply become tools of everyday use. Yet even as they disappear, these technologies afford a new way for us to interact with the environments of everyday life and with the ordinary objects within these environments. The furthering of this vision will require, in many cases, the tools and applications to possess greater levels of autonomy and an awareness of the user's context. As a result, the applications gradually depend more and more for their behaviour on the information (context information) that is relevant to user interactions. However, it is difficult to develop new context-aware applications that take into account the ever-increasing amount of context information. This is because: the context information sources vary not only in their types, but also in their availability in different environments; the developers have to spend significant programming efforts in gathering, pre-processing and managing the context information when designing and developing the new applications; and, the information sources can fail from time to time, resulting in operational disruptions or service degradation. To make such context information easily and widely available for to new context-aware applications, there is a need to provide information provisioning and management at the infrastructure level. This thesis explores the issues and challenges associated with the development of an autonomic middleware system that addresses the problems discussed earlier, with a particular focus on supporting fault-tolerant context information provisioning for multiple applications, providing the support of opportunistic use of the context sources (the sensors) and, maximising overall the system's interoperability for the open, dynamic computing environments (Ubiquitous computing, for example). The research presented in this thesis makes several key contributions. First, it introduces a novel standards-based approach to model heterogeneous information sources and data preprocessing components. Second, it details the design of a standards-based approach for supporting the dynamic composition of context information sources and pre-processing components. This approach plays an important role in supporting fault-tolerant information provisioning from the sensors and the opportunistic use of these sensors. More specifically, it enables any given piece of high-level context information, as required by applications, to be derived via multiple different pre-processing models, resulting in a higher degree of reliability. Third, it describes the design and development of an autonomic context management system (ACoMS), which harnesses the first two contributions above. Finally, the thesis shows how this autonomic context management system can support context-aware routing in wireless mesh networks. These contributions are evaluated through two corresponding case studies. The first is a practical firefighting scenario with three prototypical applications that validate the design and development of ACoMS. The second is an adaptive wireless mesh surveillance camera system that validates the concept of adopting ACoMS as a cross-layer information plane to ease the prototyping and development of new adaptive protocols and systems, and illustrates the needs of adaptive controls at the sensing layer to optimise resource usage.
3

Personalized Tag-based Collaborative Filtering & Context-Aware Recommendation for Multimedia

Kuo-Li, Che 16 August 2009 (has links)
Because electronic commerce has been flourishing in recent year, the amount and the variety of information on the web have also been rapidly increasing. However, many problems occur as the result of information overload. This thesis is to study the issue of information overload in the field of multimedia that covers not only medium of diffuse knowledge but also entertainment of everyday life. The main goal of this work is to use personalized recommendation technologies to help users select multimedia he is interested in. The thesis investigates two types of personalized recommendation: tag-based recommendation and context-aware recommendation. Regarding the former kind of recommendation, Folksonomy is the popular Web2.0 application that allows users tagging items to indicate the corresponding characteristics. These tags, provided by the users, directly or indirectly reflect his personal interests. Therefore the recommendation performance is enhanced when the tags are used with computational methods. On the other hand, the latter kind focuses on the contents and the relevant situations, because what multimedia is considered suitable for users can be different under different situations. The advantages of the personalized recommendation technology can improve performance of recommendation and take the context into account at the same time. Meanwhile this study also implements a working system for personalized multimedia recommendation.
4

CAMPOS: A context-aware model for positioning in outdoor environments that supports loosely coupled mobile activities

Moreno Córdova, Daniel Antonio January 2017 (has links)
Doctor en Ciencias, Mención Computación / En escenarios ubicuos, conocer la posición de un dispositivo es imperativo para proveer al usuario de servicios personalizados basados en location awareness, un aspecto de diseño clave en la mayoría de las aplicaciones ubicuas que dependiente de las capacidades de los dispositivos para sentir cambios en su ambiente de trabajo. No existe una solución que aborde todos los tipos de posicionamiento, pues distintos tipos de aplicaciones requieren información de posicionamiento variada en términos de exactitud, precisión, complejidad, escalabilidad, y costo. En escenarios ubicuos estándar, suele más de una estrategia de posicionamiento disponible, pero en general los dispositivos móviles no son capaces de determinar cuál es la más adecuada dado el contexto de trabajo del usuario. Además, este contexto está en constante cambio a medida que el usuario se mueve, perdiéndose conexiones a ciertos elementos del ambiente y ganándose otras. Aunque existen soluciones que abordan el posicionamiento en escenarios específicos de manera efectiva, hacerlo tomando en cuenta la mayoría de estos escenarios sigue siendo un problema abierto. La propuesta presentada en esta tesis es un modelo de posicionamiento sensible al contexto (CAMPOS), que permite a dispositivos que realizan actividades débilmente acopladas en escenarios ad-hoc al aire libre, elegir estrategias de posicionamiento adecuadas a su contexto, basado en variables contextuales predefinidas. El modelo elabora un "catálogo" de estrategias disponibles y los puntos de referencia, usando las variables contextuales como entrada para un clasificador RandomForest, el cual determina un orden de idoneidad para las estrategias de posicionamiento, lo que permite acceder a estrategias ajustadas al contexto del usuario. CAMPOS fue diseñado usando una metodología iterativa basada en casos de estudio. Primero, se realizó una revisión de literatura para determinar umbrales y valores promedio iniciales para las métricas y variables del modelo. Luego, se implementaron dos conjuntos de simulaciones; el primero para experimentar con distintos escenarios y configuraciones de dispositivos; y el segundo para evaluar el rendimiento del modelo. La batería de pruebas incluyó 27 plantillas de escenario, ejecutadas 15 veces para un total de 405 experimentos. Las variables observadas incluyen el efecto de variar la cantidad de beacons (dispositivos con capacidad de posicionamiento), la cantidad total de dispositivos, y el rango de comunicación. Todos los experimentos presentados en este trabajo se realizaron utilizando el ns-3, un simulador de redes de eventos discretos orientado a la investigación. El aporte de CAMPOS reside en que no es una nueva propuesta de estrategia de posicionamiento, ni busca mejorar el estado del arte en términos de precisión. En vez de ello, proporciona a los dispositivos de una red los medios para censar su entorno y determinar qué estrategia de posicionamiento es más adecuada para su contexto. Además, dado que CAMPOS es independiente del proceso formal de posicionamiento, si apareciesen nuevas estrategias de posicionamiento en el futuro, éstas podrían añadirse a CAMPOS con relativa facilidad, permitiendo que los dispositivos potencialmente tengan acceso a dichas estrategias a través del modelo. / El trabajo presentado en esta tesis ha sido financiado por el Programa de Becas NIC Chile, y parcialmente por Fondecyt (Chile), Proyecto 1150252
5

Context Aware and Adaptive Mobile Audio

Rangel Vacas, Inmaculada January 2005 (has links)
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.
6

Electronic Textiles for Motion Analysis

Edmison, Joshua Nathaniel 30 June 2004 (has links)
The union of electronics and textiles to form electronic textiles (e-textiles) provides a promising substrate upon which motion analysis applications can be developed and implemented. Familiarity with clothing allows sensors and computational elements to be naturally integrated into garments such that wearability and usability is preserved. The dynamics of the human body and the wide variety of sensor and processing choices render the typical prototype-based design methodology prohibitively difficult and expensive. Simulation of e-textile systems not only reduces these problems but allows for thorough exploration of the design space, faster design cycles, and more robust applications. Gait analysis, the measurement of various body motion parameters during walking for medical purposes, and context awareness, the recognition of user motions, are two immediate applications that e-textiles can impact and emphasize the feasibility of e-textiles as a medium for sensor deployment on the human body. This thesis presents the design of a simulation environment for wearable e-textile systems and demonstrates the use of the simulation via a prototype pair of e-textile pants. / Master of Science
7

An Interview Study for Developing Subjective Measures to Record Self-Reported Mood in Older Adults: Implications for Assistive Technology Development

Bhardwaj, Devvrat 14 June 2023 (has links)
Increased life expectancy has led to a 15% growth in the population of seniors (aged 65 and above) in Canada, in the last 5 years and this trend is expected to grow. However, the provision of personalized care is bottlenecked, due a severe shortage of formal caregivers in the healthcare industry. Technological solutions are proposed to supplement or replace human care, but have not been widely accepted due to their inability of dynamically adapting to user needs and context of respective situations. Affective data (i.e., emotions and moods of individuals), can be utilized to induce context-awareness and artificial emotional intelligence in such technological solutions, and thereby provide personalized support. Moreover, the capacity of brain to process affective phenomenon can serve as an indicator of onsetting neuro-degenerative diseases. This research thoroughly investigated what affect is, and how it can be used in computing in real-life scenarios. Particularly, evidence was obtained on which biological signals collected using a wearable sensor device were capable of capturing the arousal dimension of affective states (emotions and moods) of individuals. Furthermore, a qualitative study was conducted with older adults using semi-structured interviews, to determine the feasibility and acceptability of different self-report measures of mood, which are crucial to capture the valence dimension of affect. As the hypothesis that older adults would prefer a pictorial measure to self-report their mood failed, we proposed an adjective-based mood reporting instrument prototype, and laid down implications for future research.
8

A reengineering approach to reconciling requirements and implementation for context-aware web services systems

Huang, Jianchu January 2012 (has links)
In modern software development, the gap between software requirements and implementation is not always conciliated. Typically, for Web services-based context-aware systems, reconciling this gap is even harder. The aim of this research is to explore how software reengineering can facilitate the reconciliation between requirements and implementation for the said systems. The underlying research in this thesis comprises the following three components. Firstly, the requirements recovery framework underpins the requirements elicitation approach on the proposed reengineering framework. This approach consists of three stages: 1) Hypothesis generation, where a list of hypothesis source code information is generated; 2) Segmentation, where the hypothesis list is grouped into segments; 3) Concept binding, where the segments turn into a list of concept bindings linking regions of source code. Secondly, the derived viewpoints-based context-aware service requirements model is proposed to fully discover constraints, and the requirements evolution model is developed to maintain and specify the requirements evolution process for supporting context-aware services evolution. Finally, inspired by context-oriented programming concepts and approaches, ContXFS is implemented as a COP-inspired conceptual library in F#, which enables developers to facilitate dynamic context adaption. This library along with context-aware requirements analyses mitigate the development of the said systems to a great extent, which in turn, achieves reconciliation between requirements and implementation.
9

Using Ambient Radio Environment to Support Practical Pervasive Computing

Varshavsky, Alexander 26 February 2009 (has links)
Mobile applications can benefit from increased awareness of the device's context. Unfortunately, existing solutions for inferring context require special purpose sensors or beacons on the mobile devices or in the physical environment. This requirement significantly limits the deployment of these solutions. In this thesis, I argue that mobile devices can infer a substantial amount of their context by leveraging their existing wireless interfaces to monitor ambient radio sources, such as GSM cell towers or WiFi access points. I focus on two important problems in context-aware computing: localization of mobile devices and detecting proximity between mobile devices for authentication purposes. Specifically, I present an accurate localization system based on fingerprinting of GSM signals. I show that the key to more accurate GSM localization is the use of wide signal strength fingerprints that include readings from a large number of base stations. Next, I present a method that addresses the key drawback of fingerprint-based localization systems - the need to collect extensive measurements to train the system in every target environment. Finally, I show how radio environment sensing can be used to secure the communication of devices that come within close proximity. Removing the need for additional hardware on the mobile devices and in the physical environment renders the approach that I present amenable for widespread deployment.
10

Sensing and interactive intelligence in mobile context aware systems

Lovett, Tom January 2013 (has links)
The ever increasing capabilities of mobile devices such as smartphones and their ubiquity in daily life has resulted in a large and interesting body of research into context awareness { the `awareness of a situation' { and how it could make people's lives easier. There are, however, diculties involved in realising and implementing context aware systems in the real world; particularly in a mobile environment. To address these diculties, this dissertation tackles the broad problem of designing and implementing mobile context aware systems in the eld. Spanning the elds of Articial Intelligence (AI) and Human Computer Interaction (HCI), the problem is broken down and scoped into two key areas: context sensing and interactive intelligence. Using a simple design model, the dissertation makes a series of contributions within each area in order to improve the knowledge of mobile context aware systems engineering. At the sensing level, we review mobile sensing capabilities and use a case study to show that the everyday calendar is a noisy `sensor' of context. We also show that its `signal', i.e. useful context, can be extracted using logical data fusion with context supplied by mobile devices. For interactive intelligence, there are two fundamental components: the intelligence, which is concerned with context inference and machine learning; and the interaction, which is concerned with user interaction. For the intelligence component, we use the case of semantic place awareness to address the problems of real time context inference and learning on mobile devices. We show that raw device motion { a common metric used in activity recognition research { is a poor indicator of transition between semantically meaningful places, but real time transition detection performance can be improved with the application of basic machine learning and time series processing techniques. We also develop a context inference and learning algorithm that incorporates user feedback into the inference process { a form of active machine learning. We compare various implementations of the algorithm for the semantic place awareness use case, and observe its performance using a simulation study of user feedback. For the interaction component, we study various approaches for eliciting user feedback in the eld. We deploy the mobile semantic place awareness system in the eld and show how dierent elicitation approaches aect user feedback behaviour. Moreover, we report on the user experience of interacting with the intelligent system and show how performance in the eld compares with the earlier simulation. We also analyse the resource usage of the system and report on the use of a simple SMS place awareness application that uses our system. The dissertation presents original research on key components for designing and implementing mobile context aware systems, and contributes new knowledge to the eld of mobile context awareness.

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