Context Trees: Augmenting Geospatial Trajectories with Context

Exposing latent knowledge in geospatial trajectories has the potential to provide a better understanding of the movements of individuals and groups. Motivated by such a desire, this work presents the context tree, a new hierarchical data structure that summarises the context behind user actions in a single model. We propose a method for context tree construction that augments geospatial trajectories with land usage data to identify such contexts. Through evaluation of the construction method and analysis of the properties of generated context trees, we demonstrate the foundation for understanding and modelling behaviour afforded. Summarising user contexts into a single data structure gives easy access to information that would otherwise remain latent, providing the basis for better understanding and predicting the actions and behaviours of individuals and groups. Finally, we also present a method for pruning context trees, for use in applications where it is desirable to reduce the size of the tree while retaining useful information

Automatic detection of falls and fainting

Healthcare environments have always been considered an important scenario in which to apply new technologies to improve residents and employees conditions, solve problems and facilitate the performance of tasks. In this way, the use of sensors based on user movement interaction allows solving complicated situations that should be immediately addressed, such as controlling falls and fainting spells in residential care homes. However, ensuring that all the residents are always visually controlled by at least one employee is quite complicated. In this paper, we present a ubiquitous and context-aware system focused on geriatrics and residential care homes, but it could be applied to any other healthcare centre. This system has been designed to automatically detect falls and fainting spells, alerting the most appropriate employees to address the emergency. To that end, the system is based on movement interaction through a set of Kinect devices that allows the identification of the position of a person. These devices imply some development problems that authors have had to deal with, including camera location, the detection of head movements and people in horizontal position. The proposed system allows controlling each resident posture through a notification and warning procedure. When an anomalous situation is detected, the system analyses the resident posture and, if necessary, the most adequate employee will be warned to react urgently. Ubiquity and context-awareness are essential features since the proposed system has to be able to know where any employee is and what they are doing at any time. Finally, we present the outcomes of an evaluation based on the ISO 9126-4 about the usability of the system.We would like to acknowledge the project CICYT TIN2011-27767-C02-01 from the Spanish Ministerio de Ciencia e Innovación and the Regional Goverment: Junta de Comunidades de Castilla-La Mancha PPII10-0300-4174 and PII2C09-0185-1030 projects for partially funding this work

A monitoring approach for runtime service discovery

Effective runtime service discovery requires identification of services based on different service characteristics such as structural, behavioural, quality, and contextual characteristics. However, current service registries guarantee services described in terms of structural and sometimes quality characteristics and, therefore, it is not always possible to assume that services in them will have all the characteristics required for effective service discovery. In this paper, we describe a monitor-based runtime service discovery framework called MoRSeD. The framework supports service discovery in both push and pull modes of query execution. The push mode of query execution is performed in parallel to the execution of a service-based system, in a proactive way. Both types of queries are specified in a query language called SerDiQueL that allows the representation of structural, behavioral, quality, and contextual conditions of services to be identified. The framework uses a monitor component to verify if behavioral and contextual conditions in the queries can be satisfied by services, based on translations of these conditions into properties represented in event calculus, and verification of the satisfiability of these properties against services. The monitor is also used to support identification that services participating in a service-based system are unavailable, and identification of changes in the behavioral and contextual characteristics of the services. A prototype implementation of the framework has been developed. The framework has been evaluated in terms of comparison of its performance when using and when not using the monitor component

Une approche de gestion de contextes métiers pour l'accès à l'information

International audienceLa prise en compte du contexte améliore la pertinence des informations fournies par les systèmes pour les utilisateurs. Nous introduisons dans ce papier un gestionnaire de situations contextuelles métier basé sur une nouvelle définition générique du contexte. Ce gestionnaire prend en compte diverses dimensions contextuelles et agit comme un intermédiaire entre les systèmes d’accès à l’information (SAI) et les informations contextuelles. Notre approche repose sur un processus original qui gère les différentes dimensions contextuelles afin de créer une situation unique à un instant t. Pour cela, le processus de Mise En Situation (MES) utilise la base de règles qui représente la connaissance contextuelle du gestionnaire. Les situations seront utilisées par les SAI à des fins d’adaptation de processus informationnel. Par ailleurs, un processus d’extraction est proposé pour améliorer la fiabilité du gestionnaire de contexte au fil du temps en faisant évoluer sa base de connaissances. Le gestionnaire a été mis en œuvre à travers un prototype qui a été utilisé pour l’expérimentation afin de mesurer l’impact de nos propositions dans le domaine de la maintenance aéronautique

Mobile context awareness : estado da arte e casos práticos

Mestrado em Engenharia do Software na Escola Superior de Tecnologia e Gestão do Instituto Politécnico de Viana do Castelo“Com a crescente pervasividade (Zahid Farid 2013) dos Sistemas Computacionais, a importância do Context-awareness nas Ciências da Computação tem crescido nas últimas décadas.” (Lovett e O'Neill, Mobile Context Awareness 2012) Context-awareness, que se pode definir como a ideia de que os sistemas computacionais podem sentir e reagir a diferentes situações, tem sido um caso de estudo entre a comunidade. Um dos mais ubíquos dispositivos nesta evolução têm sido os dispositivos móveis, principalmente, os smartphones. A sua popularidade e a forma como o seu uso generalizado no dia a dia das pessoas tem aumentado, e o seu hardware cada vez mais sofisticado - sensores, processamento, redes sem fios - aumentaram substancialmente o potencial do Context-Awareness no mundo. Nos últimos anos têm surgido aplicações nas mais diversas áreas científicas de de negócio, que fazem uso das capacidades de determinação do contexto no sentido de permitir usufruir de serviços que, devido ao seu conhecimento do contexto do utilizador, fazem com que a experiência de utilização seja, embora num ecrã normalmente de menores dimensões, mais agradável do que o uso de outros dispositivos. Este é um dos principais segredos do sucesso da computação móvel. Neste estudo, para além da análise bibliográfica e da determinação do estado da arte, são apresentados três casos práticos de sistemas computacionais baseados da determinação do contexto do utilizador.With the pervasiveness increasing of Computational Systems, the importance of Context-awareness in Computer Science has grown in recent decades. Context-awareness, which can be defined as the idea that computer systems can sense and react to different situations, has been a case study among the community. One of the most ubiquitous devices in this evolution has been mobile devices, especially smartphones. Its popularity and the way its widespread use in people's daily lives has increased, and its increasingly sophisticated hardware - sensors, processing, wireless networks - has substantially increased the potential of Context-Awareness in the computation world. In recent years there have been applications in the most diverse scientific and business areas, which use context determination capabilities in order to make use of services that, due to their knowledge of the user context, make the experience of use , Although on a normally smaller screen, more enjoyable than the use of other devices. This is one of the secret keys of the success of mobile computing. In this study, in addition to the bibliographic analysis and the state of the art determination, three practical cases of computational systems based on user context determination were developed

Development of a GIS-based method for sensor network deployment and coverage optimization

Au cours des dernières années, les réseaux de capteurs ont été de plus en plus utilisés dans différents contextes d’application allant de la surveillance de l’environnement au suivi des objets en mouvement, au développement des villes intelligentes et aux systèmes de transport intelligent, etc. Un réseau de capteurs est généralement constitué de nombreux dispositifs sans fil déployés dans une région d'intérêt. Une question fondamentale dans un réseau de capteurs est l'optimisation de sa couverture spatiale. La complexité de l'environnement de détection avec la présence de divers obstacles empêche la couverture optimale de plusieurs zones. Par conséquent, la position du capteur affecte la façon dont une région est couverte ainsi que le coût de construction du réseau. Pour un déploiement efficace d'un réseau de capteurs, plusieurs algorithmes d'optimisation ont été développés et appliqués au cours des dernières années. La plupart de ces algorithmes reposent souvent sur des modèles de capteurs et de réseaux simplifiés. En outre, ils ne considèrent pas certaines informations spatiales de l'environnement comme les modèles numériques de terrain, les infrastructures construites humaines et la présence de divers obstacles dans le processus d'optimisation. L'objectif global de cette thèse est d'améliorer les processus de déploiement des capteurs en intégrant des informations et des connaissances géospatiales dans les algorithmes d'optimisation. Pour ce faire, trois objectifs spécifiques sont définis. Tout d'abord, un cadre conceptuel est développé pour l'intégration de l'information contextuelle dans les processus de déploiement des réseaux de capteurs. Ensuite, sur la base du cadre proposé, un algorithme d'optimisation sensible au contexte local est développé. L'approche élargie est un algorithme local générique pour le déploiement du capteur qui a la capacité de prendre en considération de l'information spatiale, temporelle et thématique dans différents contextes d'applications. Ensuite, l'analyse de l'évaluation de la précision et de la propagation d'erreurs est effectuée afin de déterminer l'impact de l'exactitude des informations contextuelles sur la méthode d'optimisation du réseau de capteurs proposée. Dans cette thèse, l'information contextuelle a été intégrée aux méthodes d'optimisation locales pour le déploiement de réseaux de capteurs. L'algorithme développé est basé sur le diagramme de Voronoï pour la modélisation et la représentation de la structure géométrique des réseaux de capteurs. Dans l'approche proposée, les capteurs change leur emplacement en fonction des informations contextuelles locales (l'environnement physique, les informations de réseau et les caractéristiques des capteurs) visant à améliorer la couverture du réseau. La méthode proposée est implémentée dans MATLAB et est testée avec plusieurs jeux de données obtenus à partir des bases de données spatiales de la ville de Québec. Les résultats obtenus à partir de différentes études de cas montrent l'efficacité de notre approche.In recent years, sensor networks have been increasingly used for different applications ranging from environmental monitoring, tracking of moving objects, development of smart cities and smart transportation system, etc. A sensor network usually consists of numerous wireless devices deployed in a region of interest. A fundamental issue in a sensor network is the optimization of its spatial coverage. The complexity of the sensing environment with the presence of diverse obstacles results in several uncovered areas. Consequently, sensor placement affects how well a region is covered by sensors as well as the cost for constructing the network. For efficient deployment of a sensor network, several optimization algorithms are developed and applied in recent years. Most of these algorithms often rely on oversimplified sensor and network models. In addition, they do not consider spatial environmental information such as terrain models, human built infrastructures, and the presence of diverse obstacles in the optimization process. The global objective of this thesis is to improve sensor deployment processes by integrating geospatial information and knowledge in optimization algorithms. To achieve this objective three specific objectives are defined. First, a conceptual framework is developed for the integration of contextual information in sensor network deployment processes. Then, a local context-aware optimization algorithm is developed based on the proposed framework. The extended approach is a generic local algorithm for sensor deployment, which accepts spatial, temporal, and thematic contextual information in different situations. Next, an accuracy assessment and error propagation analysis is conducted to determine the impact of the accuracy of contextual information on the proposed sensor network optimization method. In this thesis, the contextual information has been integrated in to the local optimization methods for sensor network deployment. The extended algorithm is developed based on point Voronoi diagram in order to represent geometrical structure of sensor networks. In the proposed approach sensors change their location based on local contextual information (physical environment, network information and sensor characteristics) aiming to enhance the network coverage. The proposed method is implemented in MATLAB and tested with several data sets obtained from Quebec City spatial database. Obtained results from different case studies show the effectiveness of our approach

Realidad aumentada

RESUMENEn este artículo estudiaremos las distintas herramientas de desarrollo que nos permiten el construir aplicaciones basadas en la Realidad Aumentada, analizando desde los inicios de esta tecnología hasta lo más reciente. Inicialmente con este documento se logra describir el trabajo realizado por nosotros como grupo de investigación, aun cuando nuestro principal objetivo es el estudiar este nuevo sistema de la Realidad Aumentada, empezaremos con el análisis de cada uno de los factores importantes para su desarrollo entre estos el analizar algunas de las características del desarrollo de software que nos brinda así como su implementación, al igual que identificar cual de esos kit de desarrollo se utilizan ya sean gratuitas o comerciales, sus ventajas y desventajas encontradas en el estudio, de igual manera el conocer la forma más fácil de que los usuarios o los desarrolladores finales utilicen están herramientas para la creación de estas aplicaciones, entre otros factores que influyen en el desarrollo de la Realidad Aumentada, como puede ser el identificar los distintos enfoques tecnológicos que esta tecnología nos brinda así como su arquitectura, al igual que todas sus aplicaciones, sus ventajas y desventajas encontradas en el estudio, de igual manera el conocer la forma de como interactúa esta tecnología con los usuarios finales, así como determinar los requerimiento de hardware y software que utilizan para la implementación de estas aplicaciones, hasta el conocer las distintas áreas de utilización de esta misma tecnología.ABSTRACT- In this article we will study the various development tools that allow us to build applications based on augmented reality for mobile devices, analyzing from the beginning of this technology to the most recent. Initially this document fails to describe the work done by us as a research group, even though our main objective is to study this new Augmented Reality system, start with the analysis of each of the important factors for the development between these analyze some of the characteristics of software development that gives us and their implementation, as well as identify which of these development kit used either free or commercial, their advantages and disadvantages encountered in the study, just as knowing the easiest way that end users or developers are using tools for creating these applications, among other factors that influence the development of Augmented Reality, such as the identification of different technological approaches to this technology and gives us its architecture, like all applications, advantages and disadvantages encountered in the study, the same way the know-how of how this technology interacts with end users and determine hardware and software requirements for implementation using of these applications to meet the various areas of utilization of the same technology