Section: New Results

Pervasive computing

Participants : Laurent Ciarletta [contact] , Tom Leclerc, Julien Siebert, Olivier Festor, André Schaff.

Vincent Chevrier(MAIA Team)

In Pervasive or Ubiquitous Computing, a growing number of communicating/computing devices are collaborating to provide users with enhanced and ubiquitous services in a seamless way. Madynes is focusing on the networking aspects of ubiquitous systems. We cooperate with the Maia (and Trio) team(s) to be able to encompass issues and research questions that combine both networking and cognitive aspects.

Pervasive Computing is about interconnected and situated computing resources providing us(ers) with contextual services. These systems, embedded in the fabric of our daily lives, are complex: numerous interconnected and heterogeneous entities are exhibiting a global behavior impossible to forecast by merely observing individual properties. Firstly, users physical interactions and behaviors have to be considered. They are influenced and influence the environment. Secondly, the potential multiplicity and heterogeneity of devices, services, communication protocols, and the constant mobility and reorganization also need to be addressed. Our research on this field as detailed in [10] is going towards both closing the loop between humans and systems and taming the complexity, using multi-modeling (to combine the best of each domain specific model) and co-simulation (to design, develop and evaluate) as part of a global conceptual and practical toolbox.

In 2011 we worked on the following research topics :

• Multi-models of these Pervasive Computing environments (including the users in the modeling and the simulations). We have been focusing on the collaborative simulations of dynamic networks/elements, namely P2P and adhoc networks using agents to drive those simulations. This work is done in collaboration with the MAIA team. The results have been extensively described in the PhD thesis of Julien Siebert [3] .

• Study of service discovery protocols, contextual metrics in adhoc networks, and Service Discovery in adhoc networks using an hybrid model between cluster-like (WCPD) and MPR-based (OLSR) broadcasting. The results have been extensively described in the PhD thesis (Contributions for Advanced Service Discovery in Ad hoc Networks) of Tom Leclerc [2] . In this thesis, we consider service discovery in MANETs, that are a collection of devices that communicate with each other over a wireless medium. Such networks are formed spontaneously whenever devices are in transmission range without any preexisting infrastructure. The main characteristic of MANETs is the high dynamics of nodes (induced by the users moving around), the volatile wireless transmissions, the user behavior, the services and their usage. We've proposed a complete solution for service discovery in ad hoc networks, from the underlying network up to the service discovery itself. A first contribution, is the Stable Linked Structure Flooding (SLSF) protocol that creates stable based cluster structure and thereby provides scalable and efficient message dissemination. The second contribution is the Stable Linked Structure Routing (SLSR) protocol that uses the SLSF dissemination structure to enable routing capabilities. Using those protocols as basis, we propose to improve service discovery by additionally considering context awareness and adaptation.

• Context awareness and mobility/usage models

  We contributed on improving simulations by coupling simulators and models that, together, can model and simulate the variety and richness of ad hoc related usage scenarios and their human characteristic. A guideline for all of our contributions was to be able to integrate and/or consider context and context awareness in both the proposed protocols and the related research tools and models. On one hand, The proposed protocols all have the capacity to adapt their efforts according to certain metrics, that represent the context. The simulator coupling architecture, on the other hand, permits to model and design scenarios in which the context, such as the service usages or the human behavior, has an impact and matters.

• Energy-constraint geolocalization, addressing, routing and management of wireless devices: a research collaboration with Fireflies RTLS was started in March 2009 and is ongoing. The initial work has been extended in a joint work with the TRIO Team and leads towards finding a global energy-cost function, and life expectancy of the wireless sensor system.

In the future work, we plan to apply those results to Cyper Physical Systems, within the Aetournos (Airborne Embedded auTonomOUs Robust Network of Objects and Sensors) platform at Loria. We aim at developing cross-layer solutions to robust routing between flying drones.

We are also working inside a CPER project towards management solutions of wireless network sensors (project ECOSUR) used to control Smart Spaces.