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We formulate and study a broadcast problem arising in multi-channel duty cycling wireless body area networks (WBANs), where the sink needs to broadcast the control message to all sensor nodes. The objective is to design robust multichannel wake-up schedule with minimum worst-case broadcast delay while guaranteeing the full broadcast diversity regardless of clock drifts and asymmetric duty cycles. To that end, we first derive the lower-bound of worst-case broadcast delay with full diversity of any broadcast protocol and then design a multichannel broadcast protocol (MCB) that satisfies the performance requirement for the latency and diversity. Finally, the simulation results demonstrate the capability of MCB of ensuring successful broadcast delivery on every channel within the theoretical worst-case broadcast delay, even under asymmetric duty cycles and any amount of clock drifts.

The goal of this roadmap paper is to summarize the state-of-the-art and identify research challenges when developing, deploying and managing self-adaptive software systems. Instead of dealing with a wide range of topics associated with the field, we focus on four essential topics of self-adaptation: design space for self-adaptive solutions, software engineering processes for self-adaptive systems, from centralized to decentralized control, and practical run-time verification & validation for self-adaptive systems. For each topic, we present an overview, suggest future directions, and focus on selected challenges. This paper complements and extends a previous roadmap on software engineering for self-adaptive systems published in 2009 covering a different set of topics, and reflecting in part on the previous paper. This roadmap is one of the many results of the Dagstuhl Seminar 10431 onSoftware Engineering for Self-Adaptive Systems,which took place in October 2010.

International audience; The PLASTIC project adopts and revisits serviceoriented computing for Beyond 3rd Generation (B3G) networks, in particular aiming at assisting the development of services targeted at mobile devices. Specifically, PLASTIC introduces the PLASTIC platform to enable robust distributed lightweight services in B3G networking environments through: • A development environment for the thorough development of SLA- and resource-aware services, which may be deployed on the various networked nodes, including handheld devices; • A service-oriented middleware leveraging multiradio devices and multi-network environments for applications and services deployed on mobile devices, further enabling context-aware and secure discovery and access to such services; • A validation framework enabling off-line and online validation of networked services regarding functional and non-functional properties.

Supporting the execution of service-oriented applications over ubiquitous networks specifically calls for a service-oriented middleware (SOM), which effectively enables ubiquitous networking while benefiting from the diversity and richness of the networking infrastructure. However, developing ubiquitous applications that exploit the specific features offered by a SOM might be a time-consuming task, which demands a deep knowledge spanning from the application domain concepts down to the underlying middleware technicalities. In this paper, first we present the model-driven development process underpinning ubiSOAP, a SOM for the ubiquitous networking domain. Then, based on the domain concepts defined by the conceptual model of ubiSOAP, its architecture and its technicalities, we propose a domain-specific environment, called ubiDSE, that aids the development of applications that exploits the ubiSOAP features, from design to implementation. ubiDSE allows developers to focus on the main behavior of the modeled systems, rather than on complex details inherent to ubiquitous environments. As part of ubiDSE, specific tools are provided to automatically generate skeleton code for service-oriented applications to be executed on ubiSOAP-enabled devices, hence facilitating the exploitation of ubiSOAP by developers.

International audience; Ambient computing requires the integration of multiple mobile heterogeneous networks. Multi-path communication, in such scenarios, can provide reliability and privacy benefits. Even though the properties of multi-path routing have been already extensively studied and a number of algorithms have been proposed, implementation of such techniques can be tricky, particularly when resource-constrained nodes are connected to each other through hybrid networks with different characteristics. In this paper we discuss the challenges involved in implementing multi-path communication on a middleware for hybrid mobile ad hoc networks. We present the PLASTIC middleware, some compelling applications of multi-path communication and the main issues concerning their implementation as a middleware-provided communication primitive.

International audience; The massive deployment of mobile networks together with the emergence of powerful portable devices has given rise to pervasive computing environments. In such environments, mobile users may discover and access services offered in surrounding networks using Service Discovery Protocols (SDPs). However, several SDPs are currently in use, each one designed for a specific target network architecture and setting. As a result, in today's multi-radio networking environment, SDPs do not equally suit each radio interface. In order to provide effective service discovery in multi-radio networks, the most resource-efficient radio interface should be chosen with respect to two main criteria: the adequacy of the interface against the SDP to be used, and energy saving, which is crucial for battery-powered devices. Toward this goal, this article assesses how to effectively take advantage of the multiple radio interfaces now embedded within wireless devices with respect to energy consumption, from the standpoint of service discovery and access. It further investigates the adequacy of legacy SDPs with the various networks, so as to classify the most appropriate networks for each SDP. Exploitation of these results is finally investigated with the description of an energy-efficient algorithm for SDP-based context sensing in a multi-radio pervasive environment.

International audience; Separation of concerns or aspects is a way to deal with the increasing complexity of systems. The separate design of models for different aspects also promotes a better reusability level. However, an important issue is then to define means to integrate them into a global model. We present a formal and tool-equipped approach for the integration of dynamic models (behaviors expressed using state diagrams) and static models (formal data types) with the benefit to share advantages of both: graphical user-friendly models for behaviors, formal and abstract models for data types. Integration is achieved in a generic way so that it can deal with both different static specification languages (algebraic specifications, Z, B) and different dynamic specification semantics

International audience; —Software cohesion concerns the degree to which the elements of a module belong together. Cohesive software is easier to understand, test and maintain. In the context of service-oriented development, cohesion refers to the degree to which the operations of a service interface belong together. In the state of the art, software cohesion is improved based on refactoring methods that rely on information, extracted from the software implementation. This is a main limitation towards using these methods in the case of Web services: Web services do not expose their implementation; instead all that they export is the Web service interface specification. To deal with this problem, we propose an approach that enables the cohesion-driven decomposition of service interfaces, without information on how the services are implemented. Our approach progressive decomposes a given service interface into more cohesive interfaces; the backbone of the approach is a suite of cohesion metrics that rely on information, extracted solely from the specification of the service interface. We validate the approach in 22 real-world services, provided by Amazon and Yahoo. We assess the effectiveness of the proposed approach, concerning the cohesion improvement, and the number of interfaces that result from the decomposition of the examined interfaces. Moreover, we show the usefulness of the approach in a user study, where developers assessed the quality of the produced interfaces.

Application development in the Internet of Things (IoT) is challenging because it involves dealing with a wide range of related issues such as lack of separation of concerns, and lack of high-level of abstractions to address both the large scale and heterogeneity. Moreover, stakehol- ders involved in the application development have to address issues that can be attributed to different life-cycles phases when developing applications. First, the application logic has to be analyzed and then separated into a set of distributed tasks for an underlying network. Then, the tasks have to be implemented for the specific hardware. Apart from handling these issues, they have to deal with other aspects of life-cycle such as changes in application requirements and deployed devices. Several approaches have been proposed in the closely related fields of wireless sensor network, ubiquitous and pervasive computing, and software engineering in general to address the above challenges. However, existing approaches only cover limited subsets of the above mentioned challenges when applied to the IoT. This thesis proposes an integrated approach for addressing the above mentioned challenges. The main contributions of this thesis are: (1) a development methodology that separates IoT application development into different concerns and provides a conceptual framework to develop an application, (2) a development framework that implements the development methodology to support actions of stakeholders. The development framework provides a set of modeling languages to specify each development concern and abstracts the scale and heterogeneity related complexity. It integrates code generation, task-mapping, and linking techniques to provide automation. Code generation supports the application develop- ment phase by producing a programming framework that allows stakeholders to focus on the application logic, while our mapping and linking techniques together support the deployment phase by producing device-specific code to result in a distributed system collaboratively hosted by individual devices. Our evaluation based on two realistic scenarios shows that the use of our approach improves the productivity of stakeholders involved in the application development.

Application development in the Internet of Things (IoT) is challenging because it involves dealing with a wide range of related issues such as lack of separation of concerns, and lack of high-level of abstractions to address both the large scale and heterogeneity. Moreover, stakehol- ders involved in the application development have to address issues that can be attributed to different life-cycles phases when developing applications. First, the application logic has to be analyzed and then separated into a set of distributed tasks for an underlying network. Then, the tasks have to be implemented for the specific hardware. Apart from handling these issues, they have to deal with other aspects of life-cycle such as changes in application requirements and deployed devices. Several approaches have been proposed in the closely related fields of wireless sensor network, ubiquitous and pervasive computing, and software engineering in general to address the above challenges. However, existing approaches only cover limited subsets of the above mentioned challenges when applied to the IoT. This thesis proposes an integrated approach for addressing the above mentioned challenges. The main contributions of this thesis are: (1) a development methodology that separates IoT application development into different concerns and provides a conceptual framework to develop an application, (2) a development framework that implements the development methodology to support actions of stakeholders. The development framework provides a set of modeling languages to specify each development concern and abstracts the scale and heterogeneity related complexity. It integrates code generation, task-mapping, and linking techniques to provide automation. Code generation supports the application develop- ment phase by producing a programming framework that allows stakeholders to focus on the application logic, while our mapping and linking techniques together support the deployment phase by producing device-specific code to result in a distributed system collaboratively hosted by individual devices. Our evaluation based on two realistic scenarios shows that the use of our approach improves the productivity of stakeholders involved in the application development.

This document describes the final implementation and the evaluation of the CHOReOS middleware. Evaluation is achieved both via the use of the middleware on CHOReOS use-cases and via synthetic experiments and simulation. The conclusion was that the implementation of the CHOReOS middleware has achieved a good level of maturity for an open source project and it is ready to be used in real-world, complex choreographies.

International audience; In this paper, we discuss how for self-adaptive systems some activities that traditionally occur at development-time are moved to run-time. Responsibilities for these activities shift from software engineers to the system itself, causing the traditional boundary between development-time and run-time to blur. As a consequence, we argue how the traditional software engineering process needs to be reconceptualized to distinguish both development-time and run-time activities, and to support designers in taking decisions on how to properly engineer such systems. Furthermore, we identify a number of challenges related to this required reconceptualization, and we propose initial ideas based on process modeling. We use the Software and Systems Process Engineering Meta-Model (SPEM) to specify which activities are meant to be performed off-line and on-line, and also the dependencies between them. The proposed models should capture information about the costs and benefits of shifting activities to run-time, since such models should support software engineers in their decisions when they are engineering self-adaptive systems.

International audience; The essential issue of interoperability in distributed systems is becoming even more pressing in the Future Internet, where complex applications will be composed from extremely heterogeneous systems. Open system integration paradigms, such as service oriented architecture (SOA) and enterprise service bus (ESB), have provided answers to the interoperability requirement. However, when it comes to integrating systems featuring heterogeneous interaction paradigms, such as client-service, publish-subscribe and tuple space, existing solutions are typically ad hoc and partial, applying to specific interaction protocol technologies. In this paper, we introduce an interoperability solution based on abstraction and merging of the common high-level semantics of interaction paradigms, which is sufficiently general and extensible to accommodate many different protocol technologies. We apply this solution to revisit the SOA- and ESB-based integration of heterogeneous distributed systems.

Given today's highly dynamic and extremely heterogeneous software systems, automatically achieving interoperability between their software components -- without modifying them--- is more than simply desirable, it is fast becoming a necessity. Although much work has been carried out on interoperability, existing solutions have not fully succeeded in keeping pace with the increasing complexity and heterogeneity of modern software, and meeting the demands of runtime support. These solutions either require developers to implement mediators, which are software entities that reconcile the differences between the implementations of software components so as to enable them to work together, or generate mediators based on declarative specifications of the composition of components or correspondences between the components' interfaces. Due to their dependency on such specifications, existing solutions are insufficient for ubiquitous environments where software components meet dynamically and interactions take place spontaneously. The main contribution of this thesis is to define an approach and provide a supporting tool for the automated synthesis and deployment of mediators in order to enable heterogeneous software components, with compatible functionalities, to interoperate. The synthesised mediators reconcile the differences between the interfaces of the components and coordinate their behaviours from the application down to the middleware layers. In this thesis, we show that ontology reasoning, constraint programming, and automata techniques can provide the basis for a practical and sound solution to automate the synthesis of mediators at both design time and runtime. The full automation of mediator synthesis removes the need for solutions requiring declarative, often detailed, specifications of how to perform mediation. We validate our approach through the development of a tool, MICS, and its experimentation with a number of case studies ranging from heterogeneous chat applications to emergency management in systems of systems. Through these case studies, we demonstrate the viability and efficiency of the automated synthesis of mediators to enable functionally-compatible software components to interoperate seamlessly.; Assurer l'interopérabilité de manière dynamique et automatique demeure un enjeu majeur dans le développement et la mise en œuvre des systèmes logiciels modernes. En effet, ces systèmes comprennent souvent plusieurs composants qui fonctionnent conjointement afin de satisfaire aux exigences des utilisateurs. Toutefois, les disparités pouvant exister entre les interfaces et les comportements de ces composants les empêchent de fonctionner ensemble, c'est-à-dire d'interopérer. Les solutions existantes visent à concilier ces disparités à travers la mise en œuvre d'intergiciels ou la génération de médiateurs. La mise en œuvre d'intergiciels n'offre qu'une solution statique, inadaptée aux environnements fortement dynamiques, tels que les environnements ubiquitaires. Les approches pour la génération de médiateurs requièrent que les correspondances entre les interfaces des composants soient préalablement spécifiées, et n'offrent de ce fait qu'une solution partiellement automatique à l'interopérabilité. Ainsi, les solutions existantes se révèlent souvent insuffisantes, particulièrement dans les environnements où les composants devant interopérer ne sont connus qu'à l'exécution. Dans cette thèse, nous définissons une approche à l'interopérabilité basée sur la synthèse automatique de médiateurs. Tout d'abord, nous intégrons la programmation par contraintes et le raisonnement ontologique afin d'inférer les traductions nécessaires pour pallier les différences entre les interfaces des composants. Ces traductions servent de base à la synthèse de médiateurs qui coordonnent les comportements des composants afin de garantir l'absence d'interblocage lors de leurs interactions. Enfin, nous procédons à l'analyse et la génération des messages au niveau intergiciel de façon à implémenter ces médiateurs. Pour valider notre approche, nous avons développé un prototype, appelé MICS, qui effectue la synthèse dynamique de médiateurs afin d'assurer l'interopérabilité entre composants en dépit de leurs différences aussi bien au niveau applicatif qu'au niveau intergiciel. Nous avons également expérimenté MICS en considérant plusieurs cas d'études allant de la médiation entre messageries instantanées à la gestion de l'interopérabilité dans les systèmes de systèmes. Cela nous a permis d'une part de démontrer la viabilité de notre solution et d'autre part d'évaluer son efficacité.

Given today's highly dynamic and extremely heterogeneous software systems, automatically achieving interoperability between their software components -- without modifying them--- is more than simply desirable, it is fast becoming a necessity. Although much work has been carried out on interoperability, existing solutions have not fully succeeded in keeping pace with the increasing complexity and heterogeneity of modern software, and meeting the demands of runtime support. These solutions either require developers to implement mediators, which are software entities that reconcile the differences between the implementations of software components so as to enable them to work together, or generate mediators based on declarative specifications of the composition of components or correspondences between the components' interfaces. Due to their dependency on such specifications, existing solutions are insufficient for ubiquitous environments where software components meet dynamically and interactions take place spontaneously. The main contribution of this thesis is to define an approach and provide a supporting tool for the automated synthesis and deployment of mediators in order to enable heterogeneous software components, with compatible functionalities, to interoperate. The synthesised mediators reconcile the differences between the interfaces of the components and coordinate their behaviours from the application down to the middleware layers. In this thesis, we show that ontology reasoning, constraint programming, and automata techniques can provide the basis for a practical and sound solution to automate the synthesis of mediators at both design time and runtime. The full automation of mediator synthesis removes the need for solutions requiring declarative, often detailed, specifications of how to perform mediation. We validate our approach through the development of a tool, MICS, and its experimentation with a number of case studies ranging from heterogeneous chat applications to emergency management in systems of systems. Through these case studies, we demonstrate the viability and efficiency of the automated synthesis of mediators to enable functionally-compatible software components to interoperate seamlessly.; Assurer l'interopérabilité de manière dynamique et automatique demeure un enjeu majeur dans le développement et la mise en œuvre des systèmes logiciels modernes. En effet, ces systèmes comprennent souvent plusieurs composants qui fonctionnent conjointement afin de satisfaire aux exigences des utilisateurs. Toutefois, les disparités pouvant exister entre les interfaces et les comportements de ces composants les empêchent de fonctionner ensemble, c'est-à-dire d'interopérer. Les solutions existantes visent à concilier ces disparités à travers la mise en œuvre d'intergiciels ou la génération de médiateurs. La mise en œuvre d'intergiciels n'offre qu'une solution statique, inadaptée aux environnements fortement dynamiques, tels que les environnements ubiquitaires. Les approches pour la génération de médiateurs requièrent que les correspondances entre les interfaces des composants soient préalablement spécifiées, et n'offrent de ce fait qu'une solution partiellement automatique à l'interopérabilité. Ainsi, les solutions existantes se révèlent souvent insuffisantes, particulièrement dans les environnements où les composants devant interopérer ne sont connus qu'à l'exécution. Dans cette thèse, nous définissons une approche à l'interopérabilité basée sur la synthèse automatique de médiateurs. Tout d'abord, nous intégrons la programmation par contraintes et le raisonnement ontologique afin d'inférer les traductions nécessaires pour pallier les différences entre les interfaces des composants. Ces traductions servent de base à la synthèse de médiateurs qui coordonnent les comportements des composants afin de garantir l'absence d'interblocage lors de leurs interactions. Enfin, nous procédons à l'analyse et la génération des messages au niveau intergiciel de façon à implémenter ces médiateurs. Pour valider notre approche, nous avons développé un prototype, appelé MICS, qui effectue la synthèse dynamique de médiateurs afin d'assurer l'interopérabilité entre composants en dépit de leurs différences aussi bien au niveau applicatif qu'au niveau intergiciel. Nous avons également expérimenté MICS en considérant plusieurs cas d'études allant de la médiation entre messageries instantanées à la gestion de l'interopérabilité dans les systèmes de systèmes. Cela nous a permis d'une part de démontrer la viabilité de notre solution et d'autre part d'évaluer son efficacité.

International audience; The sensor networking field is evolving into the Internet of Things~(IoT), owing in large part to the increased availability of consumer sensing devices, including modern smart phones. However, application development in the IoT still remains challenging, since it involves dealing with several related issues, such as lack of proper identification of roles of various stakeholders, as well as lack of suitable (high-level) abstractions to address the large scale and heterogeneity in IoT systems. Although the software engineering community has proposed several approaches to address the above in the general case, existing approaches for IoT application development only cover limited subsets of above mentioned challenges. In this paper, we propose a multi-stage model-driven approach for IoT application development based on a precise definition of the role to be played by each stakeholder involved in the process -- domain expert, application designer, application developer, device developer, and network manager. The abstractions provided to each stakeholder are further customized using the inputs provided in the earlier stages by other stakeholders. We have also implemented code-generation and task-mapping techniques to support our approach. Our initial evaluation based on two realistic scenarios shows that the use of our techniques/framework succeeds in improving productivity in the IoT application development process.

International audience; Quality of Service (QoS) in orchestrated web services compositions have been well studied with probabilistic and multi-dimensional models. Choreographies that involve message passing among services, on the other hand, require further analysis. In this paper, we begin with the set of QoS domains that may be studied in case of choreographies and the algebraic rules for their composition. As choreographies manage QoS composition in a distributed fashion, techniques to enrich functional specifications with QoS are examined using the model proposed in the CHOReOS project. These are further analyzed with choreographies that may reconfigure due to functional or QoS requirements. Studies on the effects of such reconfiguration on multiple QoS domains can lead to better understanding of optimal runtime configurations along with associated tradeoffs. A goal programming approach is also proposed to choose Pareto optimal solutions with respect to diverse QoS domains.

International audience; In recent years, there has been a growing interest towards the application of artificial intelligence approaches in software engineering (SE) processes. In the specific area of SE for self-adaptive systems (SASs) there is a growing research awareness about the synergy between SE and AI. However, just few significant results have been published. This paper briefly studies uncertainty in SASs and surveys techniques that have been developed to engineer SASs in order to tackle uncertainty. In particular, we highlight techniques that use AI concepts. We also report and discuss our own experience using Dynamic Decision Networks (DDNs) to model and support decision-making in SASs while explicitly taking into account uncertainty. We think that Bayesian inference, and specifically DDNs, provide a useful formalism to engineer systems that dynamically adapt themselves at runtime as more information about the environment and the execution context is discovered during execution. We also discuss partial results, challenges and future research avenues.

International audience; Bayesian decision theory is increasingly applied to support decision-making processes under environmental variability and uncertainty. Researchers from application areas like psychology and biomedicine have applied these techniques successfully. However, in the area of software engineering and specifically in the area of self-adaptive systems (SASs), little progress has been made in the application of Bayesian decision theory. We believe that techniques based on Bayesian Networks (BNs) are useful for systems that dynamically adapt themselves at runtime to a changing environment, which is usually uncertain. In this paper, we discuss the case for the use of BNs, specifically Dynamic Decision Networks (DDNs), to support the decision-making of self-adaptive systems. We present how such a probabilistic model can be used to support the decision-making in SASs and justify its applicability. We have applied our DDN-based approach to the case of an adaptive remote data mirroring system. We discuss results, implications and potential benefits of the DDN to enhance the development and operation of self-adaptive systems, by providing mechanisms to cope with uncertainty and automatically make the best decision.

International audience; Different modeling techniques have been used to model requirements and decision-making of self-adaptive systems (SASs). Specifically, goal models have been prolific in supporting decision-making depending on partial and total fulfilment of functional (goals) and non-functional requirements (softgoals). Different goalrealization strategies can have different effects on softgoals which are specified with weighted contribution-links. The final decision about what strategy to use is based, among other reasons, on a utility function that takes into account the weighted sum of the different effects on softgoals. [Questions/Problems] One of the main challenges about decisionmaking in self-adaptive systems is to deal with uncertainty during runtime. New techniques are needed to systematically revise the current model when empirical evidence becomes available from the deployment. [Principal ideas/results] In this paper we enrich the decision-making supported by goal models by using Dynamic Decision Networks (DDNs). Goal realization strategies and their impact on softgoals have a correspondence with decision alternatives and conditional probabilities and expected utilities in the DDNs respectively. Our novel approach allows the specification of preferences over the softgoals and supports reasoning about partial satisfaction of softgoals using probabilities. We report results of the application of the approach on two different cases. Our early results suggest the decision-making process of SASs can be improved by using DDNs.

International audience

This is Part b of Deliverable D1.4, which specifies the final CHOReOS architectural style, that is, the types of components, connectors, and configurations that are composed within the Future Internet of services, as enabled by the CHOReOS technologies developed in WP2 to WP4 and integrated in the WP5 IDRE. The definition of the CHOReOS architectural style is especially guided by the objective of meeting the challenges posed by the Future Internet, i.e.: (i) the ultra large base of services and of consumers, (ii) the high heterogeneity of the services that get composed, from the ones offered by tiny things to the ones hosted on powerful cloud computing infrastructures, (iii) the increasing predominance of mobile consumers and services, which take over the original fixed Inter- net, and (iv) the required awareness of, and related adaptation to, the continuous environmental changes. Another critical challenge posed by the Future Internet is that of security, trust and privacy. However, the study of technologies dedicated to enforcing security, privacy and trust is beyond the scope of the CHOReOS project; instead, state of the art technologies and possibly latest results from projects focused on security solutions are built upon for the development of CHOReOS use cases -if and when needed-. The CHOReOS architectural style that is presented in this deliverable refines the definition of the early style introduced in Deliverable D1.3. Key features of the CHOReOS architectural elements are as follows: (1) The CHOReOS service-based components are technology agnostic and allow for the abstraction of the large diversity of Future Internet services, and particularly traditional Business services as well as Thing-based services; a key contribution of the component formalization lies in the inference of service abstractions that allows grouping services that are functionally similar in a systematic way, and thereby contributes to facing the ULS of the Future Internet together with dealing with system adaptation through service substitution. (2) The CHOReOS middleware-layer connectors span the variety of interaction paradigms, both discrete and continuous, which are used in today's increasingly complex distributed systems, as opposed to enforcing a single interaction paradigm that is commonly undertaken in traditional SOA; a central contribution of the connector formalization is the introduction of a multi-paradigm connector type, which not solely allows having highly heterogeneous services composed in the Future Internet but also having those heterogeneous services interoperating even if based on distinct interaction paradigms. (3) The CHOReOS coordination protocols introduce the third and last type of architectural elements char- acterizing the CHOReOS style. They specifically define the structure and behavior of service-oriented systems within the Future Internet as the fully distributed composition of services, i.e., choreographies; the key contribution of the work lies in a systematic model-based solution to choreography realizability, which synthesizes dedicated coordination delegates that govern the coordination of services.

International audience; One of the main benefits of mobile participatory sensing becoming a reality is the increased knowledge it will provide about the real world, as it is expected to rely on a large number of smart and mobile devices. Nowadays, those devices have the ability to host different types of sensors that will be incorporated in every aspect of our daily lives. However, given the constantly increasing number of capable mobile devices, any participatory sensing approach should be, first and foremost, scalable. To address this challenge, we present an approach to decrease the participation of devices (in sensing tasks) in a manner that does not compromise the accuracy of the real-world information while increasing the efficiency of the overall system. To reduce the number of the devices involved, we present a probabilistic registration approach enabling only a subset of devices to register their services while still providing adequate coverage of the deployment area. Our techniques, based on a re- alistic human mobility model, allow devices to decide whether or not to register their sensing services depending on the probability of other, equivalent devices being present at the locations of their expected path. We present the design and implementation of a registration middleware based on our techniques, using which mobile devices can base their registration decision. Through experiments performed on real and simulated datasets, we show that our approach scales, while not sacrificing significant amounts of sensing coverage.

The Internet of Things (IoT) combines Wireless Sensor and Actuator Network (WSAN) (the challenge of large scale of systems), pervasive computing (the challenge of heterogeneity of nodes and the user's own interaction with these nodes), and the elements of the "traditional" Internet such as web and database servers. An important challenge in such a diverse and multidisciplinary field is the ease of application development for the stakeholders, who are involved in the IoT application development process. Several application development approaches have been proposed to address this challenge in the related field of WSANs and pervasive computing. However, very few approaches for IoT applications have evaluated their programming framework on factors such as expressiveness and development effort. The former guides the stakeholders to identify a suitable approach for given application requirements at hand. The latter helps the stakeholders the lines of code that need to be written to develop the IoT application, which involves large number of heterogeneous devices. In this paper, we evaluate our previously proposed model-driven approach, which supports the development of IoT applications, on two factors: expressiveness and development effort. The results of the expressiveness clearly indicate the subset of IoT application characteristics that can be suitably developed in our framework. Our evaluation results of the development effort show that (1) our approach drastically reduce development effort for developing IoT applications compared to node-level programming. (2) the reusability of specification and implementation across the same application domain, thus reducing development effort.

International audience; Software systems are increasingly composed of independently developed heterogeneous components. To ensure interoperability, mediators are needed that coordinate actions and translate exchanged messages between the components. We present a technique for automated synthesis of mediators, by means of a quotient operator, that is based on behavioural models of the components and an ontological model of the data domain. By not requiring a specification of the composed system, the method supports both off-line and run-time synthesis. The obtained mediator is the most general component that ensures freedom of both communication mismatches and deadlock in the composition. Validation of the approach is given by implementation of a prototype tool, while applicability is illustrated on heterogeneous holiday booking components.

The core objective of WP6 is to evaluate the CONNECT technologies under realistic situations. To achieve this goal, WP6 concentrated a significant amount of its 4th year effort on the finalization of the implementation of the GMES scenario defined during the 3rd year. The GMES scenario allows the consortium to assess the validity of CONNECT claims and to investigate the exploitation of CONNECT technologies to deal with the integration of real systems. In particular, GMES requires the connection of highly heterogeneous and independently built systems provided by the industry partners. WP6 contributed also in providing mobile collaborative applications and case studies showing the exploitation of CONNECTORs on mobile devices.

International audience; Web services are an emerging technology which has attracted much attention from both the research and the industry sectors in recent years. The exploitation of web services as components in web applications facilitates development and supports applications interoperability, regardless of the programming language and platform used. However, existing web services development standards do not take into account the fact that the provided content and the interactive functionality should be accessible to, and easily operable by, people with disabilities. This paper presents a platform named myWebAccess, which provides a mechanism for the semi-automated "repair" of web services' interaction characteristics in order to support the automatic generation of interface elements that conform to the de facto standard of the Web Content Accessibility Guidelines 2.0. myWebAccess enhances interaction quality for specific target user groups, including people with visual and motor disabilities, and supports the use of web services on diverse platforms (e.g., mobile phones equipped with a browser). The users of myWebAccess can create a personalized environment containing their favourite services, and can interact with them through interfaces appropriate to their specific individual characteristics.

Software systems are increasingly composed of independently-developed components, which are often systems by their own. This composition is possible only if the components are interoperable, i.e., are able to work together in order to achieve some user tasks. However, interoperability is often hampered by the differences in the data types, communication protocols, and middleware technologies used by the components involved. In order to enable components to interoperate despite these differences, mediators that perform the necessary data translations and coordinate the components' behaviours appropriately, have been introduced. Still, interoperability remains a critical challenge for today's and even more tomorrow's distributed systems that are highly heterogeneous and dynamic. This chapter introduces the fundamental principles and solutions underlaying interoperability in software systems with a special focus on protocols. First, we take a software architecture perspective and present the fundamentals for reasoning about interoperability and bring out mediators as a key solution to achieve protocol interoperability. Then, we review the solutions proposed for the implementation, synthesis, and dynamic deployment of mediators. We show how these solutions still fall short in automatically solving the interoperability problem in the context of systems of systems. This leads us to present the solution elaborated in the context of the European Connect project, which revolves around the notion of emergent middleware, whereby mediators are synthesised on the fly. We consider the GMES Global Monitoring of Environment and Security initiative and use it to illustrate the different solutions presented.

International audience; Self-adaptation is emerging as an increasingly important capability for many applications, particularly those deployed in dynamically changing environments, such as ecosystem monitoring and disaster management. One key challenge posed by Self-Adaptive Systems (SAS) is the need to handle changes to the requirements and corresponding behavior of a SAS in response to varying environmental condition during runtime. In this paper, we discuss the role of uncertainty in such systems, research challenges and present results from our experiences when tackling those challenges. We also review di erent modeling techniques for the development of self-adaptive systems with speci c emphasis on goal-based techniques.

The ambitious aim of CONNECT is to achieve universal interoperability between heterogeneous Networked Systems by means of on-the-fly synthesis of the CONNECTors through which they communicate. The goal of WP5 within CONNECT is to ensure that the non-functional properties required at each side of the connection going to be established are fulfilled, including dependability, performance, security and trust, or, in one overarching term, CONNECTability. To model such properties, we have introduced the CPMM meta-model which establishes the relevant concepts and their relations, and also includes a Complex Event language to express the behaviour associated with the specified properties. Along the four years of project duration, we have developed approaches for assuring CONNECTability both at synthesis time and at run-time. Within CONNECT architecture, these approaches are supported via the following enablers: the Dependability and Performance analysis Enabler, which is implemented in a modular architecture supporting stochastic verification and state-based analysis. Dependability and performance analysis also relies on approaches for incremental verification to adjust CONNECTor parameters at run-time; the Security Enabler, which implements a Security-by-Contract-with-Trust framework to guarantee the expected security policies and enforce them accordingly to the level of trust; the Trust Manager that implements a model-based approach to mediate between different trust models and ensure interoperable trust management. The enablers have been integrated within the CONNECT architecture, and in particular can interact with the CONNECT event-based monitoring enabler (GLIMPSE Enabler released within WP4) for run-time analysis and verification. To support a Model-driven approach in the interaction with the monitor, we have developed a CPMM editor and a translator from CPMM to the GLIMPSE native language (Drools). In this document that is the final deliverable from WP5 we first present the latest advances in the fourth year concerning CPMM, Dependability&Performance Analysis, Incremental Verification and Security. Then, we make an overall summary of main achievements for the whole project lifecycle. In appendix we also include some relevant articles specifically focussing on CONNECTability that have been prepared in the last period.

CONNECT adopts a revolutionary approach to the seamless networking of digital systems, that is, onthe- fly synthesis of the connectors via which networked systems communicate. Within CONNECT, the role of the WP3 work package is to devise automated and efficient approaches to the synthesis of such emergent connectors, provided the behavioral specification of the components to be connected. Thanks to WP3 scientific and technology development, emergent connectors can be synthesized on the fly as networked systems get discovered, implementing the necessary mediation between networked systems' protocols, from application down to middleware layers. This document being the final report about WP3 achievements, it outlines both: (i) specific contributions over the reporting period, and (ii) overall contributions in the area of automated, on-the-fly protocol mediation, from theory to supporting tool.

This document is the final report on use and dissemination of foreground, part of the CONNECT final report. The document provides the lists of: publications, dissemination activities, and exploitable foreground

Interoperability remains a fundamental challenge when connecting heterogeneous systems which encounter and spontaneously communicate with one another in pervasive computing environments. This challenge is exasperated by the highly heterogeneous technologies employed by each of the interacting parties, i.e., in terms of hardware, operating system, middleware protocols, and application protocols. The key aim of the CONNECT project is to drop this heterogeneity barrier and achieve universal interoperability. Here we report on the revised CONNECT architecture, highlighting the integration of the work carried out to integrate the CONNECT enablers developed by the different partners; in particular, we present the progress of this work towards a finalised concrete architecture. In the third year this architecture has been enhanced to: i) produce concrete CONNECTors, ii) match networked systems based upon their goals and intent, and iii) use learning technologies to find the affordance of a system. We also report on the application of the CONNECT approach to streaming based systems, further considering exploitation of CONNECT in the mobile environment.

This document is the final publishable summary report, part of the CONNECT final report.

International audience; The Internet of Things (IoT) domain can be considered to be an amalgamation of the hitherto well- researched Wireless Sensor and Actuator Networks (WSAN) and Pervasive Computing domains. However, application development on this platform still remains challenging. In this paper, we first discuss a specific real world instance of an oft- cited IoT application: the Smart Home application, and gain insight into IoT application development by actually implementing it. Based on the above, we then present the design, development and deployment techniques for a real world IoT system from ground up and describe of various interaction patterns that naturally occur in such applications. We further discuss the challenges faced while reusing and combining approaches from the existing domains of WSANs and Pervasive Computing, into the domain of IoT. Finally, we conclude by using these insights to present a roadmap for designing an application development framework for IoT.

International audience; The state of the art service search engines allow the users to pick the services they need, based on the quality properties, off ered by these services. To this end, the users should interact with the search engines based on the quality models that are imposed by the engines. This is a signi cant restriction towards making the service-oriented paradigm attractive to the general public. In this paper, we propose an approach that allows a user to specify his perception of quality in terms of a simple, user-de fined quality model. The proposed approach automatically maps the user-defi ned quality model to the search engine's quality model. This mapping forms the basis for ordering, grouping and, in general manipulating, the results of the user's service discovery requests.

International audience; he 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.

International audience; Models at runtime can be defined as abstract representations of a system, including its structure and behaviour, which exist in tandem with the given system during the actual execution time of that system. Furthermore, these models should be causally connected to the system being modelled, offering a reflective capability. Significant advances have been made in recent years in applying this concept, most notably in adaptive systems. In this paper we argue that a similar approach can also be used to support the dynamic generation of software artefacts at execution time. An important area where this is relevant is the generation of software mediators to tackle the crucial problem of interoperability in distributed systems. We refer to this approach as emergent middleware, representing a fundamentally new approach to resolving interoperability problems in the complex distributed systems of today. In this context, the runtime models are used to capture meta-information about the underlying networked systems that need to interoperate, including their interfaces and additional knowledge about their associated behaviour. This is supplemented by ontological information to enable semantic reasoning. This paper focuses on this novel use of models at runtime, examining in detail the nature of such runtime models coupled with consideration of the supportive algorithms and tools that extract this knowledge and use it to synthesise the appropriate emergent middleware.

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International audience; A self-adaptive system adjusts its configuration to tolerate changes in its operating environment. To date, requirements modeling methodologies for self-adaptive systems have necessitated analysis of all potential system configurations, and the circumstances under which each is to be adopted. We argue that, by explicitly capturing and modelling uncertainty in the operating environment, and by verifying and analysing this model at runtime, it is possible for a system to adapt to tolerate some conditions that were not fully considered at design time. We showcase in this paper our tools and research results.

Requirements-aware systems address the need to reason about uncertainty at runtime to support adaptation decisions, by representing quality of services (QoS) requirements for service-based systems (SBS) with precise values in run-time queryable model specification. However, current approaches do not support updating of the specification to reflect changes in the service market, like newly available services or improved QoS of existing ones. Thus, even if the specification models reflect design-time acceptable requirements they may become obsolete and miss opportunities for system improvement by self-adaptation. This articles proposes to distinguish "abstract" and "concrete" specification models: the former consists of linguistic variables (e.g. "fast") agreed upon at design time, and the latter consists of precise numeric values (e.g. "2ms") that are dynamically calculated at run-time, thus incorporating up-to-date QoS information. If and when freshly calculated concrete specifications are not satisfied anymore by the current service configuration, an adaptation is triggered. The approach was validated using four simulated SBS that use services from a previously published, real-world dataset; in all cases, the system was able to detect unsatisfied requirements at run-time and trigger suitable adaptations. Ongoing work focuses on policies to determine recalculation of specifications. This approach will allow engineers to build SBS that can be protected against market-caused obsolescence of their requirements specifications.

The Internet of Things (IoT) combines Wireless Sensor and Actuation Networks (WSANs), Pervasive computing, and the elements of the ''traditional'' Internet such as Web and database servers. This leads to the dual challenges of scale and heterogeneity in these systems, which comprise a large number of devices of different characteristics. In view of the above, developing IoT applications is challenging because it involves dealing with a wide range of related issues, such as lack of separation of concerns, need for domain experts to write low level code, and lack of specialized domain specific languages (DSLs). Existing software engineering approaches only cover a limited subset of the above-mentioned challenges. In this work, we propose an application development process for the IoT that aims to comprehensively address the above challenges. We first present the semantic model of the IoT, based on which we identify the roles of the various stakeholders in the development process, viz., domain expert, software designer, application developer, device developer, and network manager, along with their skills and responsibilities. To aid them in their tasks, we propose a model-driven development approach which uses customized languages for each stage of the development process: Srijan Vocabulary Language SVL for specifying the domain vocabulary, Srijan Architecture Language(SAL) for specifying the architecture of the application, and Srijan Network Language SNL for expressing the properties of the network on which the application will execute; each customized to the skill level and area of expertise of the relevant stakeholder. For the application developer specifying the internal details of each software component, we propose the use of a customized generated framework using a language such as Java. Our DSL-based approach is supported by code generation and task-mapping techniques in an application development tool developed by us. Our initial evaluation based on two realistic scenarios shows that the use of our techniques/framework succeeds in improving productivity while developing IoT applications.

As a subset of the Internet of Things (IoT), the Web of Things (WoT) shares many characteristics with wireless sensor and actuator networks (WSANs) and ubiquitous computing systems (Ubicomp). Yet to a far greater degree than the IoT, WSANs or Ubicomp, the WoT will integrate physical and information objects, necessitating a means to model and reason about a range of context types that have hitherto received little or no attention from the RE community. RE practice is only now developing the means to support WSANs and Ubicomp system development, including faltering first steps in the representation of context. We argue that these techniques will need to be developed further, with a particular focus on rich context types, if RE is to support WoT application development.

International audience; The behaviour of self adaptive systems can be emergent. The difficulty in predicting the system's behaviour means that there is scope for the system to surprise its customers and its developers. Because its behaviour is emergent, a self-adaptive system needs to garner confidence in its customers and it needs to resolve any surprise on the part of the developer during testing and mainteinance. We believe that these two functions can only be achieved if a self-adaptive system is also capable of self-explanation. We argue a self-adaptive system's behaviour needs to be explained in terms of satisfaction of its requirements. Since self-adaptive system requirements may themselves be emergent, a means needs to be found to explain the current behaviour of the system and the reasons that brought that behaviour about. We propose the use of goal-based models during runtime to offer self-explanation of how a system is meeting its requirements, and why the means of meeting these were chosen. We discuss the results of early experiments in self-explanation, and set out future work.

Pervasive computing is an intuitive evolution of computing paradigms driven by the wide adoption of mobile devices and wireless networks. It introduces a novel way to support users in their everyday life based on open and dynamic environments populated with unobtrusive services able to perform user tasks on the fly. Nevertheless, supporting user tasks from a functional point of view is not enough to gain the user's satisfaction. Users instead require that their tasks meet a certain Quality of Service (QoS) level. QoS is indeed an inherent and primary requisite of users going along with their required tasks. In the context of pervasive environments, fulfilling user tasks while delivering satisfactory QoS brings about several challenges that are mainly due to the openness, dynamics, and limited underlying resources of these environments. These challenges are mainly about (i) the lack of common QoS understanding among users and service providers, (ii) determining and integra- ting, on the fly, the services available in the environment and able to fulfill the functional and QoS requirements of users, and (iii) adapting the provided services at run-time to cope with QoS fluctuations and ensure meeting user requirements. To cope with the aforementioned issues, we opt for a middleware-based solution. Middle- ware represents indeed the appropriate software system to deal with common concerns of user applications such as QoS. In particular, we opt for a specific kind of middleware, viz., Ser- vice Oriented Middleware (SOM). SOM can leverage middleware technologies and the Service Oriented Computing (SOC) paradigm to enable pervasive environments as dynamic service en- vironments. Particularly, SOM can provide middleware services that allow for supporting QoS of user applications offered by pervasive environments. This thesis presents a QoS-aware service-oriented middleware for pervasive environments. The main contributions of this middleware are : (1) a semantic end-to-end QoS model that enables shared understanding of QoS in pervasive environments, (2) an efficient QoS-aware service composition approach allowing to build service compositions able to fulfill the user functional and QoS requirements, and (3) a QoS-driven adaptation approach to cope with QoS fluctuations during the execution of service compositions. The proposed contributions are implemented within a middleware platform called QASOM and their efficiency is validated based on experimental results.

The CONNECT Integrated Project aims at enabling continuous composition of Networked Systems (NSs) to respond to the evolution of functionalities provided to and required from the networked environment. CONNECT aims at dropping the interoperability barrier by adopting a revolutionary approach to the seamless networking of digital systems, that is, synthesizing on-the-fly the connectors via which networked systems communicate. The resulting emergent connectors are effectively synthesized according to the behavioral semantics of application- down to middleware-layer protocols run by the interacting parties.

Interoperability remains a fundamental challenge when connecting heterogeneous systems which encounter and spontaneously communicate with one another in pervasive computing environments. This challenge is exasperated by the highly heterogeneous technologies employed by each of the interacting parties, i.e., in terms of hardware, operating system, middleware protocols, and application protocols. The key aim of the CONNECT project is to drop this heterogeneity barrier and achieve universal interoperability. Here we report on the revised CONNECT architecture, highlighting the integration of the work carried out to integrate the CONNECT enablers developed by the different partners; in particular, we present the progress of this work towards a finalised concrete architecture. In the third year this architecture has been enhanced to: i) produce concrete CONNECTors, ii) match networked systems based upon their goals and intent, and iii) use learning technologies to find the affordance of a system. We also report on the application of the CONNECT approach to streaming based systems, further considering exploitation of CONNECT in the mobile environment.

The task of WP6 is to evaluate the CONNECT technologies under realistic situations. To achieve this goal, WP6 concentrated its 3rd year effort on the development of a main scenario in the context of GMES, which requires the connection of highly heterogeneous and independently built systems provided by the industry partners. The resulting scenario allows the consortium to assess the validity of CONNECT claims and to investigate the exploitation of CONNECT technologies in the context of the integration of real systems. Another objective of this report is to provide a first assessment of CONNECT solutions against the project's objectives stated in the DoW. The proposed assessment spans: (i) the project's overall objective of enabling on-the-fly interoperability among heterogeneous networked systems as well as (ii) the project's specific objectives related to the foundations and associated enablers to be elaborated for learning and reasoning about the interaction behaviours of networked systems and for synthesizing mediators so as to make systems interoperate.

International audience; We are moving towards a world in which everything is connected. Yet such a goal highlights the deficiencies of today's systems platforms in achieving a fundamental property of distributed systems, namely interoperability. Faced with extreme heterogeneity of computational devices and networks, how can we ensure that every system can talk to every other system?

International audience; The Future Internet environments raise challenging issues for the Service-Oriented Architectures. Due to the scalability and heterogeneity issues new approaches are thought in order to leverage the SOA to support a wider range of services and users. The CHOReOS project is part of the European Community Initiative to sketch technological solutions for the future ultra large systems. In particular, CHOReOS explores the choreography of services paradigm. Within this project, a conceptual architecture combining both the development and runtime environments is realized. This chapter introduces the CHOReOS Integrated Development and Runtime Environment, aka IDRE.