Enhanced matching engine for improving the performance of semantic web service discovery

Web services are the means to realize the Service Oriented Architecture (SOA) paradigm. One of the key tasks of the Web services is discovery also known as matchmaking. This is the act of locating suitable Web services to fulfill a specific goal and adding semantic descriptions to the Web services is the key to enabling an automated, intelligent discovery process. Current Semantic Web service discovery approaches are primarily classified into logic-based, non-logic-based and hybrid categories. An important challenge yet to be addressed by the current approaches is the use of the available constructs in Web service descriptions to achieve a better performance in matchmaking. Performance is defined in terms of precision and recall as well-known metrics in the information retrieval field. Moreover, when matchmaking a large number of Web services, maintaining a reasonable execution time becomes a crucial challenge. In this research, to address these challenges, a matching engine is proposed. The engine comprises a new logic-based and nonlogic- based matchmaker to improve the performance of Semantic Web service discovery. The proposed logic-based and non-logic-based matchmakers are also combined as a hybrid matchmaker for further improvement of performance. In addition, a pre-matching filter is used in the matching engine to enhance the execution time of matchmaking. The components of the matching engine were developed as prototypes and evaluated by benchmarking the results against data from the standard repository of Web services. The comparative evaluations in terms of performance and execution time highlighted the superiority of the proposed matching engine over the existing and prominent matchmakers. The proposed matching engine has been proven to enhance both the performance and execution time of the Semantic Web service discovery

Vers une approche d’adaptation dynamique et temps-réel du contenu informationnel d’une interface utilisateur dans un environnement ubiquitaire

Ubiquitous environments are often considered highly dynamic environments and the contextual information can change at runtime. User interface should provide the right information for the right person at the right time. Certainly, such objective can be achieved only when we deduce the realtime user’s requirements in terms of information and present this information to the user according to his current context of use. The specific goal of our research is to improve the adaptation process while improving models at runtime. A fixed model cannot handle the high dynamic in such an environment. The model can progress and change its structure to better deduce the user’s requirements. Selecting the appropriate model is not that easy. To address this problem, adaptation strategies will be based on evolutionary models. Such models can be created while integrating progressively a range of elementary actions or undergo modifications and changes as the result of interactions with the user and through reinterpretations of existing models stored by the acquisition of preceding knowledge. Our approach takes advantage of OWL-S’s properties in order to describe the dynamic functioning of Petri-nets models. We formulate a Petri-nets based elementary action by using an OWL-S atomic process. And then, we progressively compose a set of elementary actions to formulate a Petri-nets based activity. The presented method lays a sound foundation for dynamic composition of Petri-nets based modeling.L’adaptation au contexte suivant notre cadre d’étude peut être définie par la flexibilité des interfaces utilisateur à évoluer au cours de l’interaction en fonction du contexte de l’utilisateur. Et puisque généralement la pertinence des modèles dépend de la qualité de l’adaptation dynamique de l’interface, l’adaptation qui se base sur un modèle fixe de fonctionnement n’est plus appropriée dans les environnements ubiquitaires. Le Contexte a tendance à varier énormément au cours de l’interaction avec l’utilisateur dans un environnement très dynamique. D’où, la déduction de l’information nécessaire au moment approprié pour un utilisateur quelconque exige une plus grande flexibilité, ainsi une méthode statique de fonctionnement est certainement insuffisante. Cette complexité croit lorsque les informations fournies à l’utilisateur doivent correspondre à certaines caractéristiques spécifiques et individuelles des utilisateurs. Une approche de modélisation dynamique a été soigneusement décrite. Nous y avons démontré l’adaptation temps-réel des informations fournies à l’utilisateur à ses spécificités, à ses préférences, à son activité en cours et au changement de son contexte d’usage. L’utilisateur se situant dans un environnement ubiquitaire arrivera nécessairement à recevoir sur son interface l’information dont il a besoin. En procédant de cette manière, nous nous sommes parvenu implicitement à aider l’utilisateur à accomplir sa tâche en cours. Il s’agit, en fait, de la principale motivation de l’Informatique Ubiquitaire que notre stratégie nous a permis, entre autres, de la respecter

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