Nesrine Khabou

A Threshold Based Context Change Detection in Pervasive Environments: Application to a Smart Campus

Context awareness is an essential feature of pervasive applications and runtime detection of context changes is necessary for enabling context awareness. Context aware applications are applications that are able to adapt their behavior (self adaptivity property) according to the available resources, environmental conditions, user needs, etc. The self adaptivity property is enforced by four phases. Monitoring/Collecting context parameters, analyzing the collected context parameters to detect changes, planning appropriate adaptation actions and finally executing the planned actions to respond to the changes. In this paper, we focus and discuss the second phase (Analysis phase). Contrary to the most research activities in which the analysis phase is performed by comparing context parameters against fixed thresholds, we propose an analysis approach that uses a threshold comparison technique. Fixed as well as adaptive thresholds are applied to detect changes and trigger notifications that are used to deal with the changes.

QoS Monitoring and Analysis Approach for Publish/Subscribe Systems Deployed on MANET

In this paper, we propose a decentralized and adaptive approach for QoS aware publish/subscribe systems deployed on MANET. It provides monitoring and analysis modules acting at the middleware layer to detect QoS degradations between brokers. The paper presents a statistical method allowing for a permanent measurement of QoS parameters and an instantaneous detection of link failures. The statistical method used resorts to the Extreme Values Theory (EVT) and particularly uses the Gaussian and Gumbel distributions to approximate empirical distributions of the measured QoS parameter. Simulation results show the efficiency of the proposed approach.

Threshold-based context analysis approach for ubiquitous systems

In ubiquitous computing environments, applications must be able to respond to dynamic context changes in order to provide suitable services to users. A promising solution consists of developing context aware applications. In this paper, we present an approach that supports context awareness in a ubiquitous computing environment. The proposed approach focuses on handling context information including context monitoring/acquisition, context interpretation, context classification, context storage, context analysis, and context aware adaptation. In this paper, we focus on context classification and context analysis. We present a context classification approach, which takes into account the context parameter evolution behavior. Then, we define a context analysis approach for ubiquitous computing environments. The proposed analysis approach aims at analyzing contextual information and detecting significant changes. The proposed analysis approach uses a threshold comparison technique in order to detect context changes. When relevant context changes are detected, the context aware application will be notified to trigger its suitable process dynamically in order to deal with the changes. Copyright

Designing energy efficient Smart Buildings in ubiquitous environments

Smart Buildings have been the subject of research for more than two decades. The different perspectives range from monitoring and controlling energy consumption. Indeed, energy efficiency is considered as one of the promising fields of applications of the Internet of Things. Since Smart Buildings are an important part of the smart grid, their energy efficiency is vital for the environment and global sustainability. In ubiquitous computing systems, designing Smart Building applications is a challenge since these applications must ensure a trade-off between energy consumption and occupants comfort especially in ubiquitous environments. In this paper, we focus on the design of a Smart Building application in ubiquitous computing systems. The Smart Building application is able to manage energy consumption while keeping the occupants comfort. We elaborate an illustrative scenario to demonstrate the usefulness of our work.

Towards a Novel Analysis Approach for Collaborative Ubiquitous Systems

In ubiquitous computing systems, applications must be able to respond to dynamic context changes in order to maintain collaboration between entities. A promising solution consists of developing context aware applications which automatically change their behavior according to the user needs, the available resources and the surrounding environment. Furthermore, a context aware application is characterized by a closed feed back loop with four phases: Monitoring, Analysis, Planning and Execution. In this paper, we focus on the second phase and we propose an analysis approach of collaborative ubiquitous systems which aims at analyzing context information and detecting significant abnormal changes. The proposed approach relies on thresholds in order to track down context changes. Once relevant context changes occur, the context aware application will be notified to trigger its suitable process dynamically in order to deal with the changes.

Designing an Analysis Procedure for Context Aware Applications in Ubiquitous Environments

Embedded and invisible computing resources are paving the way to a new paradigm known as ubiquitous computing. In this paradigm, more attention needs to be paid to the development of context aware applications. Several proposals for the development of these applications are based on a context awareness loop with four phases. First, monitoring context information (Collect). Second, analyzing the collected context information to detect changes (Analysis), third, deciding adaptation actions relative to the changes (Decide). Finally, executing the corresponding adaptation actions to deal accordingly with the changes (Act). In this paper, we discuss the Analysis phase. We propose an analysis approach that aims at detecting the context changes and raising notifications when changes occur. The analysis approach is based on thresholds and formalized through an analysis procedure that aims to facilitate the design of the analysis phase to develop context aware applications in ubiquitous environments. The analysis procedure is described by a set of steps used by the application designers to design context aware applications. In order to demonstrate the usefulness of our approach, we present a Smart Building case study and we illustrate the use of our analysis procedure through a Smart Building application scenario.

A novel analysis approach for the design and the development of context-aware applications

Abstract In this paper, we propose a novel analysis approach, called ANALOG, for the design and the development of context-aware applications able to detect context change and to predict context parameter values. Our approach is described by two analysis procedures, (a) an analysis procedure for detection and (b) an analysis procedure for prediction. The proposed analysis procedures aim to offer a support for application designers allowing them to design easily context-aware applications. Each procedure is achieved by a sequence of steps performed by the designers. We describe first our analysis approach presented by the analysis procedures. Then, we give some implementation details of our approach. Afterwards, we show the usefulness of the analysis approach through presenting two execution scenarios related to a smart building case study. Finally, to illustrate the effectiveness of our approach, we present different experiments related to (i) the processing time of the analysis approach and (ii) the CPU and the memory overhead introduced by our approach.

A context change detection approach for ubiquitous environments

The increase of mobile devices leads to the growth of demands for pervasive applications. Due to the heterogeneity of devices in terms of resources, capabilities, the applications have to adapt themselves to the context changes. This requires the development of context aware applications able to perform four phases. First, collecting context; second, analysing context to detect changes; third, planning adaptation actions; finally executing the adaptation actions. We focus on the second phase. Its aim is to analyse context to detect changes. In this paper, we propose a context analysis approach that relies on different thresholds to detect changes and raise notifications when changes occur. The analysis approach requires three steps. Storing context; then classifying context; finally, calculating and updating thresholds to detect changes. The context classification depends on the user needs. For the threshold calculation, different mathematical models are applied in order to update thresholds.

Analysis process for context aware applications in pervasive environments

Context awareness is one of the major research areas of pervasive computing. Several proposals for the design of context aware applications rely on a closed feedback loop that performs four phases. Monitoring and collecting context (phase 1), analyzing the collected context to detect changes (phase 2), deciding adaptation actions related to the changes (phase 3) and performing and executing the corresponding adaptation actions (phase 4) to deal with the changes. In this paper, we discuss the analysis phase (phase 2). We propose an analysis approach that aims at detecting the context changes and raising notifications when changes occur. The analysis approach is formalized through an analysis process that aims to facilitate the design of the analysis phase for a context aware application. The analysis process is described by a graph illustrating a set of steps that must be executed to perform the analysis process. In order to demonstrate the usability of our approach, we present a Smart Building case study.