Mining Service Abstractions (NIER Track)

International audienceSeveral lines of research rely on the concept of service abstractions to enable the organization, the composition and the adaptation of services. However, what is still missing, is a systematic approach for extracting service abstractions out of the vast amount of services that are available all over theWeb. To deal with this issue, we propose an approach for mining service abstractions, based on an agglomerative clustering algorithm. Our experimental ndings suggest that the approach is promising and can serve as a basis for future research

Automated architectural component classification using concept lattices

While the use of components grows in software development, building effective component directories becomes a critical issue as architects need help to search components in repositories. During the life-cycle of component-based software, several tasks, such as construction from scratch or component substitution, would benefit from an efficient component classification and retrieval. In this paper, we analyze how we can build a classification of components using their technical description (i.e. functions and interfaces) in order to help automatic as well as manual composition and substitution. The approach is implemented in the CoCoLa prototype, which is dedicated to Fractal component directory management and validated through a case study.Laboratorio de Investigación y Formación en Informática Avanzad

Service-Oriented Middleware for the Future Internet: State of the Art and Research Directions

International audienceService-oriented computing is now acknowledged as a central paradigm for Internet computing, supported by tremendous research and technology development over the last ten years. However, the evolution of the Internet, and in particular, the latest Future Internet vision, challenges the paradigm. Indeed, service-oriented computing has to face the ultra large scale and heterogeneity of the Future Internet, which are orders of magnitude higher than those of today's service-oriented systems. This article aims at contributing to this objective by identifying the key research directions to be followed in light of the latest state of the art. This article more specifically focuses on research challenges for service-oriented middleware design, therefore investigating service description, discovery, access and composition in the Future Internet of services

An effective services framework for sharing educational resources

Nowadays, the growing number of software tools to support e-learning and the data they rely upon are valuable resources, supporting different aspects of the complex learning and teaching processes, including designing learning content, delivering learning activities, and evaluating students’ learning performance. However, sharing these educational resources efficiently and effectively is a challenge: there are many resources, these have not been described accurately and in general they do not interoperate, and it is common for the tools to rely on different technologies. This thesis explores a solution – a novel educational services framework – to improve the sharing of current e-resources, by applying the latest service technologies in the context of higher education. Our findings suggest that the proposed framework is effective to deal with the technical and educational issues in resource discovery, interoperability and reusability, however, there are still technical challenges remaining for implementing this service framework. This research is divided into 3 phases. The first phase investigates the sharing of elearning resources through a literature survey, and identifies limitations on current developments. In the second phase, the current problems relating to resource sharing are addressed by a proposed educational service framework, which contains both educational and technical components. Through a case study, nine e-learning services and their dataflows are identified. To determine the technical components of the framework, a novel Educational Service Architecture is proposed, which allows resources to be better described, structured and connected, by following the principles of discoverability, interoperability and reusability in service technologies. In the third phase, part of the framework is implemented and evaluated by two studies. In the first study, users’ experiences were collected via a simulation experiment, to compare the effectiveness of a service prototype with that of the use of current technologies. During the second part of the evaluation, technical challenges for implementing the services framework were identified via a case study, involving the implementation of another service prototype

On the construction of decentralised service-oriented orchestration systems

Modern science relies on workflow technology to capture, process, and analyse data obtained from scientific instruments. Scientific workflows are precise descriptions of experiments in which multiple computational tasks are coordinated based on the dataflows between them. Orchestrating scientific workflows presents a significant research challenge: they are typically executed in a manner such that all data pass through a centralised computer server known as the engine, which causes unnecessary network traffic that leads to a performance bottleneck. These workflows are commonly composed of services that perform computation over geographically distributed resources, and involve the management of dataflows between them. Centralised orchestration is clearly not a scalable approach for coordinating services dispersed across distant geographical locations. This thesis presents a scalable decentralised service-oriented orchestration system that relies on a high-level data coordination language for the specification and execution of workflows. This system’s architecture consists of distributed engines, each of which is responsible for executing part of the overall workflow. It exploits parallelism in the workflow by decomposing it into smaller sub-workflows, and determines the most appropriate engines to execute them using computation placement analysis. This permits the workflow logic to be distributed closer to the services providing the data for execution, which reduces the overall data transfer in the workflow and improves its execution time. This thesis provides an evaluation of the presented system which concludes that decentralised orchestration provides scalability benefits over centralised orchestration, and improves the overall performance of executing a service-oriented workflow

Initial Architectural Style for CHOReOS Choreographies (D1.3)

While the development of CHOReOS systems build on well-known paradigms associated with service-oriented architectures (e.g., services, service bus and service choreography), the supporting architectural style re- quires accounting for the challenges posed by the future Internet, i.e., ultra large scale, high heterogeneity, increased mobility, and awareness & adaptability. This deliverable then revisits the traditional definitions of service-oriented component (i.e., service), connector (interaction protocol and related service bus for interop- erability) and configuration (system-wide architecture composing services according to orchestration or more general choreography patterns) to meet the FI challenges. Specifically, CHOReOS components enable lever- aging the diversity of Web-based services that integrate in the FI (i.e., WS∗ and RESTful web-based services, and from business to thing-based services) as well as the ultra large service base envisioned for the FI. As for CHOReOS connectors, they bring together the highly heterogeneous interaction paradigms that are now used in today's increasingly complex distributed systems and further support interoperability across heterogeneous paradigms. Finally, CHOReOS coordination protocols foster choreography-based coordination for the sake of scalability, while preventing undesired behavior (i.e., undesired service interactions that would violate the specified choreography). A key aspect of the proposed CHOReOS architectural style is to introduce novel ab- stractions for all its elements, which enable leveraging the wide diversity of the FI, in all the dimensions of scale, heterogeneity and mobility. The CHOReOS style further sets the base ground for the development (from design to implementation) of the CHOReOS Integrated Development and Runtime Environment, and especially for the specification and design of choreography-based systems (studied in WP2 complemented with WP4 work on Governance and V&V) and the development of the CHOReOS service-oriented middleware (studied in WP3)

Using information visualization techniques to support web service discovery

The increasing number of web services published over the Web highlights the need for an effective method for users to find appropriate web services. Existing web service discovery methods do not effectively aid a user in finding suitable web services. The current methods provide textual lists of web services that the user is required to explore and manually evaluate. Thus, these methods lead to time-consuming and ineffective web service discovery. The aim of this research was to investigate using information visualization (IV) techniques to effectively support web service discovery. The node-and-link network IV technique was selected as the most appropriate IV technique to visualize web service collections. A prototype, called SerViz, was developed as a tool for interactive visualization of web service collections incorporating the node-and-link IV technique and an alphabetical list-based technique. SerViz used the Programmable Web web service collection as the sample web service collection. A usability evaluation was conducted to compare these techniques. Ninety percent of participants preferred the network IV technique for visualizing web service collections. The network IV technique was also faster for browsing. Several usability problems were identified with the network IV technique. This motivated a need for implementing an alternative IV technique in SerViz. The node-and-link tree IV technique was selected as it was more structured than the network IV technique. A usability evaluation was conducted to compare the network and tree IV techniques. Participants slightly preferred the tree IV technique as the technique to visualize web service collections. The tree IV technique was faster for browsing the web service collection while the network IV technique was faster for searching and filtering. This research has determined that IV techniques can be used to effectively support web service discovery. Future work will involve using IV techniques to support collaborative web service discovery. Keywords: Web Service Discovery, Information Visualization, Web Service Collections, Information Visualization Techniques