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Abstract

In this position paper, we address the needs and motivations for practical evaluation of ubiquitous mobile systems.We are particularly interested in the validation of resilience mechanisms for such systems. We advocate the use of real experiments that complement simulation for the evaluation of actual prototypes. Indeed, experimental validation is particularly appealing when resilience properties such as safety or availability are an issue. We then propose and discuss some technological trails for the implementation of such an evaluation platform and its validation.

Mots-Clés / Keywords

Abstract

Autonomous robots offer alluring perspectives in numerous application domains: space rovers, satellites, medical assistants, tour guides, etc. However, a severe lack of trust in their dependability greatly reduces their possible usage. In particular, autonomous systems make extensive use of decisional mechanisms that are able to take complex and adaptative decisions, but are very hard to validate. This paper proposes a fault tolerance approach for decisional planning components, which are almost mandatory in complex autonomous systems. The proposed mechanisms focus on development faults in planning models and heuristics, through the use of diversification. The paper presents an implementation of these mechanisms on an existing autonomous robot architecture, and evaluates their impact on performance and reliability through the use of fault injection.

Abstract

Autonomous robots offer alluring perspectives in numerous application domains: space rovers, satellites, medical assistants, tour guides, etc. However, a severe lack of trust in their dependability greatly reduces their possible usage. In particular, autonomous systems make extensive use of decisional mechanisms that are able to take complex and adaptative decisions, but are very hard to validate. This paper proposes a fault tolerance approach for decisional planning components, which are almost mandatory in complex autonomous systems. The proposed mechanisms focus on development faults in planning models and heuristics, through the use of diversi ication. The paper presents an implementation of these mechanisms on an existing autonomous robot architecture, and evaluates their impact on performance and reliability through the use of fault injection.

Mots-Clés / Keywords

Abstract

Autonomous robots make extensive use of decisional mechanisms, such as planning. These mechanisms are able to take complex and adaptative decisions, but are notoriously hard to validate. This paper reports an investigation of how redundant, diversi ied models can be used to tolerate residual design faults in such mechanisms. A fault-tolerant temporal planner has been designed and implemented using diversity, and its effectiveness demonstrated experimentally through fault injection. The pa- per describes the implementation of the fault-tolerant planner and discusses the results obtained. The results indicate that diversi ication provides a noticeable improvement in planning reliability with a negligible performance overhead. However, further improvements in reliability will require implementation of a on-line checking mechanism for assessing plan validity before execution.

Mots-Clés / Keywords

Abstract

Mobile devices are increasingly relied on but are used in contexts that put them at risk of physical damage, loss or theft. We consider a fault-tolerance approach that exploits spontaneous interactions to implement a collaborative backup service. We deine the constraints implied by the mobile environment, analyze how they translate into the storage layer of such a backup system and examine various design options. The paper concludes with a presentation of our prototype implementation of the storage layer, an evaluation of the impact of several compression methods, and directions for future work.

Mots-Clés / Keywords