Achieving interoperability through semantics-based technologies: the instant messaging case

The success of pervasive computing depends on the ability to compose a multitude of networked applications dynamically in order to achieve user goals. However, applications from different providers are not able to interoperate due to incompatible interaction protocols or disparate data models. Instant messaging is a representative example of the current situation, where various competing applications keep emerging. To enforce interoperability at runtime and in a non-intrusive manner, mediators are used to perform the necessary translations and coordination between the heterogeneous applications. Nevertheless, the design of mediators requires considerable knowledge about each application as well as a substantial development effort. In this paper we present an approach based on ontology reasoning and model checking in order to generate correct-by-construction mediators automatically. We demonstrate the feasibility of our approach through a prototype tool and show that it synthesises mediators that achieve efficient interoperation of instant messaging applications

Dynamic Component Selection for SCA Applications

International audienceService Oriented Computing (SOC) has gained maturity and there have been various specifications and frameworks for realization of SOC. One such specification is the Service Component Architecture (SCA), which defines applications as assembly of heterogeneous components. However, such assembly is defined once and remains static for fixed components throughout the application life-cycle. To address this problem, we have previously proposed an approach for dynamic selection of components in SCA, based on functional semantic matching and non-functional strategic matching using policy descriptions in SCA. In this paper, we extend our existing approach by providing further flexibility in component selection and present the architecture and implementation of our system. An evaluation of the system is also reporte

Concurrency and Interaction in Complex Systems

The authors emphasize the actual relevance and need of formal methods for the advancements of complex systems, and present briefly the other papers contained in this issue

A delay and cost balancing protocol for message routing in mobile delay tolerant networks

The increasing pervasiveness of mobile devices with networking capabilities has led to the emergence of Mobile Delay Tolerant Networks (MDTNs). The characteristics of MDTNs, which include frequent and long-term partitions, make message routing a major challenge in these networks. Most of the existing routing protocols either allocate an unlimited number of message copies or use a xed number of message copies to route a message towards its destination. While the first approach unnecessarily oods the network, the rigidity of the second approach makes it ine cient from the viewpoint of message replication. Hence, the question that we address in this paper is: "How to dynamically allocate message copies in order to strike a balance between the delay and cost of message delivery?". We present a novel adaptive multi-step routing protocol for MDTNs. In each routing step, our protocol reasons on the remaining time-tolive of the message in order to allocate the minimum number of copies necessary to achieve a given delivery probability. Experiment results demonstrate that our protocol has a higher delivery ratio and a lower delivery cost compared to the state-of-the-art Spray-and-Wait and Bubble protocols

ACCIO: How to Make Location Privacy Experimentation Open and Easy

The advent of mobile applications collecting and exploiting the location of users opens a number of privacy threats. To mitigate these privacy issues, several protection mechanisms have been proposed this last decade to protect users' location privacy. However, these protection mechanisms are usually implemented and evaluated in monolithic way, with heterogeneous tools and languages. Moreover, they are evaluated using different methodologies, metrics and datasets. This lack of standard makes the task of evaluating and comparing protection mechanisms particularly hard. In this paper, we present ACCIO, a unified framework to ease the design and evaluation of protection mechanisms. Thanks to its Domain Specific Language, ACCIO allows researchers and practitioners to define and deploy experiments in an intuitive way, as well as to easily collect and analyse the results. ACCIO already comes with several state-of-the-art protection mechanisms and a toolbox to manipulate mobility data. Finally, ACCIO is open and easily extensible with new evaluation metrics and protection mechanisms. This openness, combined with a description of experiments through a user-friendly DSL, makes ACCIO an appealing tool to reproduce and disseminate research results easier. In this paper, we present ACCIO's motivation and architecture, and demonstrate its capabilities through several use cases involving multiples metrics, state-of-the-art protection mechanisms, and two real-life mobility datasets collected in Beijing and in the San Francisco area

A semi-automatic framework for the design of rational resilient collaborative systems

Collaborative systems (e.g., P2P instant messaging, file sharing, live streaming applications) constitute the largest traffic of today\u2019s Internet. Common to all these systems is the assumption that, in return to the service offered by the collaborative system, users are willing to participate by sharing their resources with others. However, in practice, these systems suffer from rational users, i.e. users that benefit from the system without contributing their fair share to it. A number of solutions have been devised in the literature to deal with the problem of rational users in collaborative systems. However, most of these solutions are tailored to specific systems and thus lack flexibility and re-usability. In this paper, we propose RACOON, the first framework for RAtional resilient COllabOrative system desigN. RACOON relies on an extensible model that allows a system designer to specify the protocol steps and the different types of rational users he wants to consider. Furthermore, RACOON relies on game theory to reason on the behaviour of rational users. Finally, RACOON includes a simulation module that allows performance-oriented tuning of the system. Throughout the paper, we show how we used RACOON for the design of a rational-resilient, collaborative live-streaming application. Performance evaluation realised on one hundred real machines shows that the configuration proposed by RACOON allows all users to visualise a quality stream even in presence of rational users

Yarta: A Middleware for Managing Mobile Social Ecosystems

International audienceWith the increased prevalence of advanced mobile devices (the so-called \smart" phones), interest has grown in mobile social ecosystems, where users not only access traditional Web-based social networks using their mobile devices, but are also able to use the context information provided by these devices to further enrich their interactions. In complex mobile social ecosystems of the future the heterogeneity of software platforms on constituent nodes, combined with their intrinsic distributed nature and heterogeneity of representation of data and context raises the need for middleware support for the development of mobile social applications. In this paper, we propose Yarta, a novel middleware designed for mobile social ecosystems (MSE), which takes into account the heterogeneity of both deployment nodes and available data, the intrinsic decentralized nature of mobile social applications, as well as users' privacy concerns. To validate our approach, we show how we developed two mobile social applications over Yarta, and report on both its e ciency and ease-of use by way of extensive evaluation on smart phones and laptops