The large number of devices characterizing Wireless Sensor Networks (WSNs) provide the benefits of observing, tracking, and recording everything; nonetheless, the cumulative computing power of those devices is typically not utilized, and the few implementations taking advantage of it neglect privacy or are application-specific. This manuscript describes a privacy-preserving protocol that enables WSN nodes to jointly compute an arbitrary function without disclosing their own private inputs. The computation takes place at data source nodes, while computation instructions and intermediate results move across the network secured by cryptography. The protocol relies on the Onion Routing technique to provide uniformly distributed network traffic and confine the knowledge a foreign actor can gain from monitoring messages traveling the network. We show that the communication protocol is privacy-preserving against the external and internal attacker models, and we validate our protocol implementation using the NS3 network simulator.

Nowadays, with the increasing number of data sources, especially in environmental domain, earth observation programs face major challenges for environmental data exploitation, mainly due to data sources heterogeneity of different types such as access techniques, used protocols, languages, data formats, etc. Although typical solutions abstract from this heterogeneity with a layer of data services, the development of such systems remains tedious in this context. In this paper, we propose an approach based on Model-Driven Engineering (MDE) combined with semantic annotations, to automate data service development on top of data sources. Our work contributes to the development of integrated service-based architectures driven by automatic service generation, data integration from existing environmental systems and automatic service annotations. Our solution, applied to the detection of natural disasters, provides 1) appropriate modelling of data sources and services to apply model-to-text (M2T) transformations, 2) automatic generation of Representational State Transfer (REST) data service code template, 3) automatic generation of semantically annotated Hypermedia-based descriptors of these services. We have implemented and evaluated our solution with a set of real data sources provided by the Sahara and Sahel Observatory (OSS), OpenWeatherMap and CHIRPS.

Recently, RESTful services, designed as resources, have seen their popularity rising and have shown their potential in composing reliable Web-scale environments (Web applications, Web platforms, Web of Things (WoT), etc.). However, discovering the necessary resources for a composition is becoming more challenging. This is due to 1) the growing number of published Web-based resources, and 2) the highly dynamic nature of the WoT environment, in which smart devices, connected to the Web platform, are exposed as resources. In this paper, we propose an automatic resource discovery, applicable in hybrid Web-based environments providing static linked resources always available on the Web, and connecting dynamic resources that can be connected to and removed from the Web at different time periods. The solution presents an indexing schema that makes resource discovery process fast, especially in large-scale environments. Experiments were conducted in different environment setups to test the effective performance of our approach.

Web service discovery is a challenging task that has received a lot of interest in the last decade. Several approaches have been proposed, however, many limitations remain. In this paper, we focus on collaborative semantic discovery of RESTful services according to the HATEOAS principle. We propose an approach based on 1) semantic links between services; 2) user profile clustering to dynamically measure user similarity for queries in a similar context, and 3) a user profile ontology to manage users and corresponding services. A prototype has been implemented to evaluate our proposal and show its effectiveness.

The Web of Things (WoT) extends the Internet of Things to provide users with high-level features, involving physical objects connected through Web technologies and standards. Avatar-based infrastructures is one of the most promising solution for the WoT. Avatars are component-based software agents that extend physical objects and are able to reason about contextual information. A major challenge of the WoT is to allow applications to adapt to their environment. In this paper, we propose an approach to process multi-purpose adaptation in an avatar-based WoT infrastructure. Our approach relies on a context meta-model that offers accurate granularity levels of information required for the different types of adaptation involved in WoT applications. We show how avatar components pre-process data from different sources, handle an operational context model, and respond to adaptation requests. We evaluate the performance of our approach and compare the effects of our adaptation process in different experimental conditions.

Nowadays, the use of RESTful Web services promotes stateless service interaction and decentralized hypermedia-driven discovery and composition. However, there is a need for models and tools to drive user interaction as well as description, discovery and composition of RESTful services. In this paper, we provide a solution to help users manage, share and discover workflows of RESTful Web services. We annotate RESTful Web services with semantic information, and introduce the notion of composition directory as a Web resource that assists a user in sharing, managing and discovering workflows. Users' composition directories form a decentralized repository of service workflows connected by hypermedia links. We illustrate the benefits of our approach with a typical scenario and show that the breadth-first search algorithm efficiently answers users' goals by crawling through composition directories and exploiting semantic annotations through a series of experiments.

Organizations, companies and Web platforms hold large amounts of unused data. These data are trapped in separate data sources, locked up in legacy formats and only reachable through several different protocols, making usage difficult. It is therefore necessary to manage this multiplicity of data sources in order to build a solution able to combine this multi-origin data into a coherent smart data set. We define a meta-model and models to describe data source diversity in a flexible way. We therefore propose an adaptive architecture that generates data integration workflows at runtime. We evaluate our approach to offer scalability, responsiveness, and dynamic and transparent data source management. We apply our approach in a live scenario from a French company to show how it adapts to industrial needs and facilitates smart data production and reuse. This paper describes our models and strategies and presents our resource-oriented architecture.

Web service composition is the art of combining multiple platform independent and modular pieces of software with varied configurations, to achieve an efficient solution for a complex business process. Though, web service composition has been an important area of research in the last decade, however the issue is expected to exacerbate in the 'Future Internet', as it is expected to house billions of services, with thousands offering the same functionality. In this context, maintaining an operational and solid set of Web service configurations will be a challenging task. Moreover, a centralized solution for Web service composition in the Future Internet scenario would be another issue. In this paper, we present a technique inspired from ElectroMagnetism in physics to create an environment which facilitates the selection of a service from a set of similar services. The proposed model achieves service composition in a decentralized environment without involving a centralized orchestrator. To validate the proposed technique in-silico experiments were conducted whose results demonstrate good performance in terms of completion time and load balancing. Further, the proposed technique is validated in-house (within our Institute's Intranet and with real users) by deploying real Web services on decentralized nodes. The results obtained via simulation are verified through a prototype based on the proposed model. We present, discuss and compare the effectiveness of the proposed work in the results section.

As the number of connected objects increases, there is a need to offer rich user experience and facilitate communication between physical objects with Web-based solutions. Our work relies on the notion of avatar to extend an object on the Web. We herein propose a model for the avatar to expose functionalities based on the capabilities objects offer. We motivate our work with a temperature regulation scenario and we evaluate the applicability of our proposal with an implementation.

Data as a Service (DaaS) builds on service-oriented technologies to enable fast access to data resources on the Web. However, this paradigm raises several new privacy concerns that traditional privacy models do not handle. In addition, DaaS composition may reveal privacy-sensitive information. In this paper, we propose a formal privacy model in order to extend DaaS descriptions with privacy capabilities. The privacy model allows a service to define a privacy policy and a set of privacy requirements. We also propose a privacy-preserving DaaS composition approach allowing to verify the compatibility between privacy requirements and policies in DaaS composition. We propose a negotiation mechanism that makes it possible to dynamically reconcile the privacy capabilities of services when incompatibilities arise in a composition. We validate the applicability of our proposal through a prototype implementation and a set of experiments.

Privacy is still among the key challenges that keep hampering DaaS service composition solution. Indeed services may follow different, conflicting privacy specifications with respect to the data they use and provide within a composition. In this paper, we propose an approach for privacy-aware composition of DaaS services. Our approach allows verifying the compatibility of privacy specifications of services involved in a composition. In the case when any composition will be incompatible in terms of privacy, we introduce a novel approach based on negotiation to reach compatibility of concerned services. The negotiation approach is cautiously operated with without any privacy damaging of services. We validate the applicability of our proposal through a set of experiments.

Rich types of data offered by data as a service(DaaS) in the cloud are typically associated with different and complex data concerns that DaaS service providers, data providers and data consumers must carefully examine and agree with before passing and utilizing data. Unlike service agreements, data agreements, reflecting conditions established on the basis of data concerns, between relevant stakeholders have got little attention. However, as data concerns are complex and contextual, given the trend of mixing data sources by automated techniques, such as data mash up, data agreements must be associated with data discovery, retrieval and utilization. Unfortunately, exchanging data agreements so far has not been automated and incorporated into service and data discovery and composition. In this paper, we analyze possible steps and propose interactions among data consumers, DaaS service providers and data providers in exchanging data agreements. Based on that, we present a novel service for composing, managing, analyzing data agreements for DaaS in cloud environments and data marketplaces.

Data Mashup is a special class of mashup application that combines information on the fly from multiple data sources to respond to transient business needs. Data mashup is a difficult task that would require an important programming skill on the side of mashups' creators, and involves handling many challenging privacy and security concerns raised by data providers. This situation prevents non-expert users from mashing up data at large. In this paper, we present a declarative approach for mashing-up data. The approach allows data mashup creators to build data mashups without any programming involved. The approach builds the mashups automatically and takes into account the data's privacy concerns. We evaluate the efficiency of the approach via a thorough set of experiments. The results show that handling data privacy introduces only a negligible cost in the mashup building time.

In this paper, we investigate the combination of configuration and query rewriting for semantic Web service composition. Given a user query and a set of service descriptions, we rely on query rewriting to find services that implement the functionalities expressed in the user query (discovery stage). Then, we use configuration to capture dependencies between services, and to generate a set of composed Web services described as a directed acyclic graph, while maintaining validity with respect to business rules (orchestration stage).Finally, we propose a semantic ranking algorithm to rank results according to user preferences (classification stage).The techniques used in our approach take into account the semantics of concepts utilized to describe the elements (services, business rules, query and user preferences) involved in the composition process. We provide a formal approach and its implementation, together with experiments on Web services from different application domains.

In this paper, we present Meerkat, a dynamic framework for preserving privacy in Web services. We define a Web service-aware privacy model that deals with the privacy of input data, output data, and operation usage. We introduce a matching protocol that caters for partial and total privacy compatibility. Finally, we propose a negotiation model to reconcile clients' requirements with providers' policies in case of incompatibility.

This paper presents a Web services composition approach that is built upon three layers known as component, community, and composite. The contribution of each layer towards this approach is assessed from two perspectives known as organization and management. Furthermore this paper discusses how Web services in a community are specialized into abstract and concrete. Interactions between abstract/- concrete Web services and composite Web services happen through a driver known as Open Service Connectivity. This driver permits first, binding any abstract Web service to any composite Web service and second, triggering any concrete Web service from any composite Web service.

Web services composition is a keystone in the development of interoperable systems. However, despite the widespread adoption of Web services, several obstacles still hinder their smooth automatic semantic reconciliation when being composed. Consistent understanding of data exchanged between composed Web services is hampered by various implicit modeling assumptions and representations. Our contribution in this article revolves around context and how it enriches data exchange between Web services. In particular, a context-based mediation approach to solve semantic heterogeneities between composed Web services is presented.

Summary form only given. Centralized architectures based on the client server paradigm show their limits each time the Internet extends its capabilities. They present problems in terms of security, robustness, performance, high needs for administration. Short time solutions like load balancing and replication, or purchasing of more powerful hardware tend to cope with these limits for a while, but do not provide a definitive answer to these problems. Currently, different proprietary approaches hinder attempts to enabling communication between heterogeneous systems, while the Internet is developing toward a better interoperability with service-oriented architectures. Open source and standardization efforts allow building a framework providing an original answer to interoperability and scalability over the Internet. In this paper, we consider that the distributed nature of P2P platforms allied with the standardized WS architecture, based on SOAP and WSDL represent a powerful framework for building dynamic interoperable and decentralized information systems. The aim of our work is to allow P2P participants to dynamically access and compose semantic WS outside of the P2P network, and to improve existing WS publication and discovery by using the decentralization of P2P architecture. In order to achieve this goal, we propose a mediation framework built around the JXTA P2P architecture. This framework is based on the OWL-S language as a means for a semantic description of WS interfaces, in order to solve heterogeneity problems.