Supporting Dynamic Service Composition at Runtime based on End-user Requirements

Network-based software application services are receiving a lot of attention in recent years, as observed in developments as Internet of Services, Software as a Service and Cloud Computing. A service-oriented computing ecosystem is being created where the end-user is having an increasingly more active role in the service creation process. However, supporting end-users in the creation process, at runtime, is a difficult undertaking. Users have different requirements and preferences towards application services, use services in different situations and expect highly abstract mechanisms in the creation process. Furthermore, there are different types of end-users: some can deliver more detailed requirements or can be provided with more advanced request interface, while others can not. To tackle these issues and provide end-users with personalised service delivery, we claim that runtime automated service composition mechanisms are required. In this paper we present the DynamiCoS framework, which aims at supporting the different phases required to provide end-users with automatic service discovery, selection and composition process. In this paper we also present the developed prototype and its evaluation

A Framework for the Evaluation of Semantics-based Service Composition Approaches

The benefits of service composition are being largely acknowledged in the literature nowadays. However, as the amount of available services increases, it becomes difficult to manage, discover, select and compose them, so that automation is required in these processes. This can be achieved by using semantic information represented in ontologies. Currently there are many different approaches that support semantics-based service composition. However, still little effort has been spent on creating a common methodology to evaluate and compare such approaches. In this paper we present our initial ideas to create an evaluation framework for semantics-based service composition approaches. We use a collection of existing services, and define a set of evaluation metrics, confusion matrix-based and time-based. Furthermore, we present how composition evaluation scenarios are generated from the collection of services and specify the strategy to be used in the evaluation process. We demonstrate the proposed framework through an example. Currently there are mechanisms and initiatives to address the evaluation of the semantics-based service discovery and matchmaking approaches. However, still few efforts have been spent on the creation of comprehensive evaluation mechanisms for semantics-based service composition approaches

Towards runtime discovery, selection and composition of semantic services

Service-orientation is gaining momentum in distributed software applications, mainly because it facilitates interoperability and allows application designers to abstract from underlying implementation technologies. Service composition has been acknowledged as a promising approach to create composite services that are capable of supporting service user needs, possibly by personalising the service delivery through the use of context information or user preferences. In this paper we discuss the challenges of automatic service composition, and present DynamiCoS, which is a novel framework that aims at supporting service composition on demand and at runtime for the benefit of service end-users. We define the DynamiCoS framework based on a service composition life-cycle. Framework mechanisms are introduced to tackle each of the phases and requirements of this life-cycle. Semantic services are used in our framework to enable reasoning on the service requests issued by end users, making it possible to automate service discovery, selection and composition. We validate our framework with a prototype that we have built in order to experiment with the mechanisms we have designed. The prototype was evaluated in a testing environment using some use case scenarios. The results of our evaluation give evidences of the feasibility of our approach to support runtime service composition. We also show the benefits of semantic-based frameworks for service composition, particularly for end-users who will be able to have more control on the service composition process

Lion: Listen online. Using GraphQL as a mediator for data integration and ingestion

Data integration is the task of providing a unified view of multiple data sources. Thesesources can be, and are typically, heterogeneous in their data model, data query language (DQL), and data manipulation language (DML). In this thesis is described a system called”Listen Online”, or Lion for short. Lion utilizes the GraphQL specification to provide integration for querying of web services. Lion provides a general structure by which arbitrary mediators can be used within a query. Lastly, by building on top of open source libraries,Lion provides the open source community with components that enable it to function in the form of GraphQL servers, visual layout libraries, and query builders

Desarrollo de una interfaz web para la composición de servicios REST

Treball final de Màster Universitari en Sistemes Intel.ligents. Codi: SIU043. Curs acadèmic 2014-2015El creciente aumento del uso de servicios web REST se debe a la simplicidad y ligereza que ofrece este estilo arquitectónico. Este incremento propicia la necesidad de reutilizar los servicios existentes para componer servicios nuevos. Sin embargo, el proceso de composición es un proceso complejo que resulta difícil de automatizar por lo que mayoría de enfoques proponen métodos manuales o semiautomáticos. En este documento se presenta la memoria del trabajo de fin de máster perteneciente al máster de sistemas inteligentes de la Universitat Jaume I. El proyecto consiste en el desarrollo de una interfaz web que a partir de un repositorio de servicios web REST permite gestionar sus descripciones así como componer manualmente un nuevo servicio reutilizando algunos de los existentes. El presente documento describe el proceso que se ha seguido a la hora de realizar el proyecto. En primer lugar, se establece el contexto y la motivación, se indican los objetivos, y se muestra la planificación temporal, la tecnología usada y la arquitectura del sistema. Seguidamente se hace un pequeño estado del arte sobre la composición de servicios web en el que se muestra una taxonomía de los métodos y técnicas que existen para componer. Además, también se habla sobre REST y los servicios web. A continuación se definen los requisitos que tiene que cumplir la aplicación, se detalla el diseño y la implementación realizados así como las pruebas. También se expone un escenario de uso para ver el correcto funcionamiento de la interfaz. Finalmente se presentan las conclusiones y el trabajo futuro

Dynamic connector synthesis: revised prototype implementation

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

Vers une médiation de composition dynamique de Services Web dans des environnements ubiquitaires.

Nowadays, high market pressure stimulates service providers to be more competitive in order to attract more subscribers. The user-centric approach, which aims to provide adapted services to user’s needs, is attracting a great attention thanks to the emergence of ubiquitous environment. The interoperability, either that between users and services or that among services, is favored by the adoption of SOA (Service Oriented Architecture), as a development model as well as the Web services that combine the advantages of this model with the language and development technologies devoted to Internet-based applications. In particular, the dynamic Web service composition is currently the main practice which allows achieving enhanced services, as an answer to increasing complex requests by users for various types of services, by combining functionalities of multiple services within a single and personalized service session. Indeed, already available services are numerous and of various natures, similar services can be provided by heterogeneous platforms. In a ubiquitous environment, users are mobile, either by changing the access network or by changing the terminal, or even both of them. This leads in turn to potential needs on mobility of services, both in terms of the (physical) server and in terms of the (equivalent) services. It is in this dynamic and ubiquitous context that we have conducted our research. In particular, we focused on the particular topic of mediation of dynamic composition of web services. We proposed a mediation approach which consists in identifying and organizing various concrete services (both SOAP and RESTful) to form a set of abstract services, and, from this knowledge base, to provide users the possibility to realize personalized service session according to their needs through dynamic composition of some of the abstract services and their mapping to best suited concrete services. We considered three types of service composition (SOAP/SOAP, SOAP/RESTful, RESTful/RESTful) in our mediation. Depending on the user’s will, this composition (Mashup on the side of the mediator) can be returned to him/her, so that he/she can invoke it autonomously; or the mediator can ensure the realization of the composed services and provide only the final result to the user. In the latter case, the mediator can handle the aforementioned different mobility. This feature is achieved by exploring the mechanism of the virtual community to select the most appropriate concrete service corresponding to the abstract service and maintain the continuity of service while respecting its requested QoS. The virtual community has been developed within the ANR/UBIS project (to which part of this thesis is related).De nos jours, l’ouverture à la concurrence stimule les fournisseurs de services à être de plus en plus compétitifs et à attirer de plus en plus d’abonnés afin de faire face aux fortes pressions du marché. L’approche user-centric, qui consiste à fournir le plus rapidement possible des services adaptés aux besoins de l’usager, attire de plus en plus d’attention suite à l’émergence de l’environnement ubiquitaire. L’interopérabilité, aussi bien celle entre utilisateur et service que celle entre les services, est favorisée par l’adoption de SOA (architecture orientée service) comme modèle de développement, ainsi que les services Web qui combinent les avantages de ce modèle avec les langages et technologies développés pour Internet.Notamment, la composition dynamique de service Web est considérée comme un atout majeur, qui permet de répondre à des requêtes complexes en combinant les fonctionnalités de plusieurs services au sein d’une session personnalisée. Les services sont divers et variés et des services similaires pourraient être fournis depuis des plateformes hétérogènes. Dans un environnement ubiquitaire, les utilisateurs sont mobiles, cette mobilité se manifeste aussi bien à travers les réseaux empruntés que les terminaux utilisés. Ceci entraine une possible mobilité de services (aussi bien en termes de serveur effectif qu’en termes de services équivalents). C’est dans ce contexte dynamique et ubiquitaire, qui est celui choisi par le projet ANR/UBIS (dont cette thèse est partiellement issue), que nous avons mené nos recherches sur le thème particulier de la médiation de composition dynamique de services web. Plus précisément, nous proposons une approche de médiation qui consiste à recenser puis organiser de divers services concrets (aussi bien SOAP que RESTFul) pour constituer une panoplie des services abstraits d’une part, puis, à partir desquels, à offrir aux usagers les possibilités de réaliser des services personnalisés selon leur besoins (logique métier) par composition dynamiquement de ces services abstraits et de leur association avec le service concret le plus approprié. Nous avons considéré les trois types de composition de services (SOAP/SOAP, SOAP/RESTful, RESTful/RESTful) dans notre médiation. Selon le souhait de l’usager, cette composition (Mashup du coté de médiateur) peut lui être retournée et que l’usager peut invoquer de manière autonome, ou bien le médiateur peut assurer la réalisation du service composé et fournir seulement le résultat final à l’usager. Dans ce dernier cas, les différentes mobilités peuvent être prises en compte par le médiateur, qui s’appuie sur les mécanismes de la communauté virtuelle préconisés par le projet UBIS pour activer les services concrets les plus appropriés correspondant à un servic

Semantic search and composition in unstructured peer-to-peer networks

This dissertation focuses on several research questions in the area of semantic search and composition in unstructured peer-to-peer (P2P) networks. Going beyond the state of the art, the proposed semantic-based search strategy S2P2P offers a novel path-suggestion based query routing mechanism, providing a reasonable tradeoff between search performance and network traffic overhead. In addition, the first semantic-based data replication scheme DSDR is proposed. It enables peers to use semantic information to select replica numbers and target peers to address predicted future demands. With DSDR, k-random search can achieve better precision and recall than it can with a near-optimal non-semantic replication strategy. Further, this thesis introduces a functional automatic semantic service composition method, SPSC. Distinctively, it enables peers to jointly compose complex workflows with high cumulative recall but low network traffic overhead, using heuristic-based bidirectional haining and service memorization mechanisms. Its query branching method helps to handle dead-ends in a pruned search space. SPSC is proved to be sound and a lower bound of is completeness is given. Finally, this thesis presents iRep3D for semantic-index based 3D scene selection in P2P search. Its efficient retrieval scales to answer hybrid queries involving conceptual, functional and geometric aspects. iRep3D outperforms previous representative efforts in terms of search precision and efficiency.Diese Dissertation bearbeitet Forschungsfragen zur semantischen Suche und Komposition in unstrukturierten Peer-to-Peer Netzen(P2P). Die semantische Suchstrategie S2P2P verwendet eine neuartige Methode zur Anfrageweiterleitung basierend auf Pfadvorschlägen, welche den Stand der Wissenschaft übertrifft. Sie bietet angemessene Balance zwischen Suchleistung und Kommunikationsbelastung im Netzwerk. Außerdem wird das erste semantische System zur Datenreplikation genannt DSDR vorgestellt, welche semantische Informationen berücksichtigt vorhergesagten zukünftigen Bedarf optimal im P2P zu decken. Hierdurch erzielt k-random-Suche bessere Präzision und Ausbeute als mit nahezu optimaler nicht-semantischer Replikation. SPSC, ein automatisches Verfahren zur funktional korrekten Komposition semantischer Dienste, ermöglicht es Peers, gemeinsam komplexe Ablaufpläne zu komponieren. Mechanismen zur heuristischen bidirektionalen Verkettung und Rückstellung von Diensten ermöglichen hohe Ausbeute bei geringer Belastung des Netzes. Eine Methode zur Anfrageverzweigung vermeidet das Feststecken in Sackgassen im beschnittenen Suchraum. Beweise zur Korrektheit und unteren Schranke der Vollständigkeit von SPSC sind gegeben. iRep3D ist ein neuer semantischer Selektionsmechanismus für 3D-Modelle in P2P. iRep3D beantwortet effizient hybride Anfragen unter Berücksichtigung konzeptioneller, funktionaler und geometrischer Aspekte. Der Ansatz übertrifft vorherige Arbeiten bezüglich Präzision und Effizienz

Semantic search and composition in unstructured peer-to-peer networks

This dissertation focuses on several research questions in the area of semantic search and composition in unstructured peer-to-peer (P2P) networks. Going beyond the state of the art, the proposed semantic-based search strategy S2P2P offers a novel path-suggestion based query routing mechanism, providing a reasonable tradeoff between search performance and network traffic overhead. In addition, the first semantic-based data replication scheme DSDR is proposed. It enables peers to use semantic information to select replica numbers and target peers to address predicted future demands. With DSDR, k-random search can achieve better precision and recall than it can with a near-optimal non-semantic replication strategy. Further, this thesis introduces a functional automatic semantic service composition method, SPSC. Distinctively, it enables peers to jointly compose complex workflows with high cumulative recall but low network traffic overhead, using heuristic-based bidirectional haining and service memorization mechanisms. Its query branching method helps to handle dead-ends in a pruned search space. SPSC is proved to be sound and a lower bound of is completeness is given. Finally, this thesis presents iRep3D for semantic-index based 3D scene selection in P2P search. Its efficient retrieval scales to answer hybrid queries involving conceptual, functional and geometric aspects. iRep3D outperforms previous representative efforts in terms of search precision and efficiency.Diese Dissertation bearbeitet Forschungsfragen zur semantischen Suche und Komposition in unstrukturierten Peer-to-Peer Netzen(P2P). Die semantische Suchstrategie S2P2P verwendet eine neuartige Methode zur Anfrageweiterleitung basierend auf Pfadvorschlägen, welche den Stand der Wissenschaft übertrifft. Sie bietet angemessene Balance zwischen Suchleistung und Kommunikationsbelastung im Netzwerk. Außerdem wird das erste semantische System zur Datenreplikation genannt DSDR vorgestellt, welche semantische Informationen berücksichtigt vorhergesagten zukünftigen Bedarf optimal im P2P zu decken. Hierdurch erzielt k-random-Suche bessere Präzision und Ausbeute als mit nahezu optimaler nicht-semantischer Replikation. SPSC, ein automatisches Verfahren zur funktional korrekten Komposition semantischer Dienste, ermöglicht es Peers, gemeinsam komplexe Ablaufpläne zu komponieren. Mechanismen zur heuristischen bidirektionalen Verkettung und Rückstellung von Diensten ermöglichen hohe Ausbeute bei geringer Belastung des Netzes. Eine Methode zur Anfrageverzweigung vermeidet das Feststecken in Sackgassen im beschnittenen Suchraum. Beweise zur Korrektheit und unteren Schranke der Vollständigkeit von SPSC sind gegeben. iRep3D ist ein neuer semantischer Selektionsmechanismus für 3D-Modelle in P2P. iRep3D beantwortet effizient hybride Anfragen unter Berücksichtigung konzeptioneller, funktionaler und geometrischer Aspekte. Der Ansatz übertrifft vorherige Arbeiten bezüglich Präzision und Effizienz