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Browsing by Author "Soares, Christophe Pinto de Almeida"

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  • Interference-free Integration of Commercial Off-The-Shelf Components in Pervasive Computing Systems
    Publication . Soares, Christophe Pinto de Almeida; Moreira, Rui Silva; Morla, Ricardo
    The nineties were marked by futuristic visions of massive proliferation and interconnection of ubiquitous off-the-shelf systems. This innovation movement became known as ubicomp (ubiquitous computing). This new computing age raised new challenges in different areas, such as, ambient intelligence and applied artificial intelligence, software engineering planning, distributed systems and services, machine learning and security. These research trends gained preponderance in ubicomp but particularly the generic use of commercial off-the-shelf systems became pivotal in the massive integration and deployment of pervasive computing technology. This gains special importance when we think about device integration in the same household where unplanned interactions between users and ubicomp systems may occur (e.g., entertainment, communication, and health-related devices). Unplanned interactions are a serious concern since they may cause unsafe behavior on some of the systems. Think, for example, behavior interferences between communication or entertainment applications with health-related devices. In such ubicomp scenarios the deployed system should be aware of the surrounding context and adapt to cope with the user needs and nearby deployed systems. These systems are supposed to support and execute services for the users but are usually planned and developed independently and by different vendors. Therefore, the deployment and integration of these systems in the same environment or house are usually conducted in an unplanned manner, i.e., without a standard integration procedure that may allow inter-system connection and reconfiguration. Moreover, the traditional software development processes do not aim to avoid interference between systems during the conception stage. Furthermore, it is hard to identify and understand a priori all possible interactions between every possible system. The integration task is therefore complex since there are multiple possible systems combinations and variations. Moreover, since these systems are not usually aware of other systems in the same household, their behavior may potentially trigger a chain of unexpected reactions and jeopardize other systems operations. When these actions result in unexpected behavior, this problem is known as functional behavior interference or feature interaction. The ubicomp integration of off-the-shelf systems suffers from potential interference issues, and current deployment strategies do not cope with such problems yet. This thesis presents a novel graph-based approach for representing the expected behavior of commercial off-the-shelf devices and applications, their interactions, and for detecting interference among pervasive computing systems deployed on the same home context. A set of home care scenarios is used to assess the applicability of this approach. We consider also two setups where this approach can be applied: i) in a pre-deployment setup, where simulation is used to detect possible instances of interference, and ii) at run-time, collecting observations from devices and applications and detecting interference as it occurs. For pre-deployment and simulation, we use Opensim to recreate a household with several deployed systems. For run-time, we use Simple Network Management Protocol for systems state introspection and a sliding window mechanism to process the collected data-stream. The proposed model uses graph-analysis algorithms, which together with behavior introspection mechanisms, allow us to identify the occurrences of functional interferences, their potential sources and subjects, and the associated shared media through which such interferences may occur. The interference analysis is performed through a chain of working filters, each performing a specific check for interference. The intra-system filter provides mechanisms for identifying uncommon individual system behavior. The intersystem filter analyzes interferences between systems by inspecting if each medium is affected and shared by more than one system during their operations. A combined approach, using intra-system and inter-system outputs, allows us to identify any misbehavior and associated causing interactions and media dependencies. The detection of functional interference, both in predeployment and post-deployment scenarios, will allow defining reconfiguration or adaptation strategies, thus guaranteeing a safe integration of ubicomp systems.
    2015Doctoral thesis Restricted access Show more
  • LoCoBoard: quadro interactivo de baixo custo recorrendo a algoritmos de visão por computador
    Publication . Soares, Christophe Pinto de Almeida; Moreira, Rui Silva; Torres, José
    Na actual era digital, a adopção de interfaces naturais entre o homem e a máqui-na, torna-se cada vez mais pertinente. Na educação, em particular, a utilização de ferra-mentas interactivas para melhorar as práticas pedagógicas, auxiliar a compreensão de conceitos complexos e permitir o trabalho colaborativo, constitui uma vantagem inequí-voca. Em particular os quadros interactivos (QI) são uma ferramenta muito útil cujo uso está cada vez mais disseminado por vários níveis de ensino. Neste aspecto, a panóplia de soluções comerciais disponíveis é vasta, mas o custo associado é geralmente elevado, para equipar de forma generalizada os estabelecimentos de ensino, principalmente nos países de economia mais débil. Este trabalho propõe neste contexto, um sistema de quadro interactivo de código aberto, com requisitos de hardware muito reduzidos (i.e., um computador com uma câmara de vídeo WEB, um videoprojector e um dispositivo emissor de infravermelhos com o formato de caneta), o que poderá contribuir para a massificação do seu uso. Neste trabalho apresenta-se a estrutura física e lógica de um protótipo de Quadro Interactivo de baixo custo designado por LoCoBoard (Low Cost Interactive Board). O desenvolvimento deste sistema baseou-se na implementação de vários módulos, desde a captura de imagens, pré-processamento das frames, detecção e seguimento de pontos de interesse (PI) e distribuição de coordenadas através do protocolo Tangible UI Object Protocol (TUIO). Apresenta-se ainda a avaliação de desempenho dos diferentes algo-ritmos de detecção de pontos de interesse uma vez que estes fazem parte de um dos módulos centrais da arquitectura do sistema. Finalmente, estrutura-se ainda uma ferra-menta de análise que nos permite comparar o protótipo LoCoBoard com sistemas afins. In the current digital age, the integration of natural interfaces between humans and machines is becoming important than ever. This is particularly relevant in education as the utilisation of interactive tools can provide clear advantages by improving teaching practices, facilitating the comprehension of complex concepts and permitting collabora-tive work. More particularly, interactive whiteboards are very useful tools that are being increasingly used in various levels of education. There is a vast catalogue of business solutions available for interactive whiteboards. However, these solutions are often costly which can deter their full implementation in all types of schools, especially in countries with more fragile economies. In this context, this dissertation proposes the adoption of an open source interac-tive whiteboard, which have low-cost hardware requirements such as a webcam-equipped computer, a video projector and an infrared device. Such solution will easy the access to interactive whiteboards and consequently increase its widespread. This dissertation discusses the physical and logical structure of a low cost inter-active framework prototype called LoCoBoard (Low Cost Interactive Board). The de-velopment of this system was based on the implementation of several modules includ-ing the capture of images, pre-processing of frames, detection and tracking of points of interest (POI) and coordinated distribution through the Tangible UI Object Protocol (TUIO). Additionally, the performance of different algorithms, used to detect points of interest, are evaluated and presented, as they are part of one of the core modules of the system. Finally, an analysis framework is used for comparing the LoCoBoard prototype with related systems. Dans l'ère numérique actuelle, l'adoption d'interfaces naturelles entre l'homme et la machine prend une place de plus en plus importante. C'est le cas dans l'éducation où l'utilisation d'outils interactifs s'avère d'une très grande utilité que ce soit pour améliorer les pratiques pédagogiques, aider à la compréhension de concepts complexes ou faciliter le travail collaboratif. Les tableaux interactifs (TI) par exemple sont des outils de plus en plus répandu dans le milieu de l’éducation et ce à tous les niveaux (e.g., Ecole, Col-lège, Universités). Il existe d'ailleurs à ce jour un grand éventail de solutions dispo-nibles, mais leurs coûts généralement élevés ne permettent pas d’équiper toutes les insti-tutions et plus particulièrement dans les pays pauvres. Cette thèse présente donc dans ce contexte un prototype de tableau interactif à bas prix, basé sur une solution open-source et composé d’un hardware simple (un ordi-nateur, une caméra vidéo, un vidéoprojecteur et un émetteur infrarouge IR) tout ceci dans le but de le rendre facilement réutilisable et surtout abordable à tous. Il s'intitule LoCoBoard (Low Cost Interactive Whiteboard). Toute la structure logique et physique de ce prototype est expliquée dans cette thèse. La conception de ce système repose sur le développement de divers éléments comme la capture d’image, le prétraitement d’images, la détection et le suivi (cf. trac-king) de points d’intérêt (PI) et la distribution de coordonnées à travers le protocole Tangible UI Object Protocol (TUIO). Pour mettre en évidence la performance des diffé-rents algorithmes développés pour détecter les points considérés d'intérêt capturés par la caméra vidéo, une étude comparative a été effectuée et est présenté dans cette thèse. Ces algorithmes constituent l'un des éléments essentiels de l'architecture du système LoCo-Board. Pour finir, les caractéristiques du système LoCoBoard sont détaillées par le biais d’une analyse comparative avec celles d’une série de systèmes identiques.
    2009Master thesis Open access Show more