Mimoun Malki

Development of semantic web services: model driven approach

The power of Web Service (WS) technology lies in the fact that it establishes a common, vendor-neutral platform for integrating distributed computing applications, in intranets as well as the Internet at large. Semantic Web Services (SWSs) promise to provide solutions to the challenges associated with automated discovery, dynamic composition, enactment, and other tasks associated with managing and using service-based systems. One of the barriers to a wider adoption of SWS technology is the lack of tools for creating SWS specifications. OWL-S is one of the major SWS description languages. This paper presents a model driven approach to facilitate the construction of OWL-S specifications. The methodology is divided into three main steps. In the first step we reverse engineered WSDL documents into UML profile models that enable the use of high-level graphical models as an integration platform for semantic web services. In the second step, suitable domain ontologies are used for the semantic annotation of the UML models. Finally, in the third step a conversion tool will generate automatically the OWL-S description from these UML models. The UML profile provides flexibility as it can expresses multiple semantic web service concepts.

Acquiring owl ontologies from data-intensive web sites

The availability and the proliferation of ontologies are crucial for the success of the Semantic Web. As consequence, a great number of researchers are working on method and techniques to build ontologies through automatic or semi-automatic processes, which perform knowledge acquisition from texts, dictionaries and structured and semi-structured information sources. On the other hand, reverse engineering, when applied to software engineering, uses a collection of theories, methodologies and techniques to support information abstraction and extraction from a piece of software. In this paper we present a semi-automatic reverse engineering approach to acquire OWL ontology corresponding to the content of relational database. Our approach is based on the idea that the semantics extracted by analyzing HTML forms will be used to restructure and enrich the relational schema. OWL ontology is constructed through a set of transformation rules from the enriched schema. The main reason for this construction is to make the relational database information that is available on the Web machine-processable and reduce the time consuming task of ontology creation.

Extraction of Object-oriented Schemas from Existing Relational Databases: a Form-driven Approach

In this paper, we present our Form-driven approach for reverse engineering of relationa databases. This methodology uses the information extracted from both form structure and instances as a database reverse engineering input using an interaction with a user. Through a combination of forms structures and data instances analysis, forms relational sub-schemas and their constraints are derived. These relational sub-schemas are mapped to object sub-schemas, which will be merging into global object-oriented schema that presents the whole underlying databases. The resulting global object-oriented schema must be validated as a rich and correct representation of the application domain.

Composing Data Services with Uncertain Semantics

With the emergence of the open data movement, hundreds of thousands of datasets from various concerns are now freely available on the Internet. The access to a good number of these datasets is carried out through Web services which provide a standard way to interact with data. In this context, users queries often require the composition of multiple data Web services to be answered. Defining the semantics of data services is the first step towards automating their composition. An interesting approach to define the semantics of data services is by describing them as semantic views over a domain ontology. However, defining such semantic views cannot always be done with certainty, especially when the services outputs are too complex. In this paper, we propose a probabilistic approach to model the semantics uncertainty of data services. In our approach, a data service with an uncertain semantics is described by several possible semantic views, each one is associated with a probability. Services along with their possible semantic views are represented in a Block-Independent-Disjoint (noted BID) probabilistic service registry, and interpreted based on the Possible Worlds Semantics. Based on our modeling, we study the problem of interpreting an existing composition involving services with uncertain semantics. We also study the problem of compositing uncertain data services to answer a user query, and propose an efficient method to compute the different possible compositions and their probabilities.

Reverse Engineering Existing Web Service Applications

Semantic Web Service (SWS) enrich Web Service technology with formal, ontology-based descriptions of service functionalities and capabilities at the semantic level, thus enabling semantic-based discovery, composition, dynamic binding and orchestration.Several solutions were proposed for the specification of the Semantic Web Services, in this paper, we propose a reverse engineering based approach to specify Web Service according to the Web Service Modeling Ontology (WSMO).

Concept-based clustering of textual documents using SOM

The classification of textual documents has been widely studied. The majority of classification approaches use supervised learning methods, which are acceptable for rather small corpora allowing experts to generate representative sets of data for the training, but are not feasible for significant flows of data. Unsupervised classification methods discover latent (hidden) classes automatically while minimizing human intervention. Many such methods exist, among which Kohonen self- organizing maps (SOM), which gather a certain number of similar objects without prior information. In this paper, we evaluate and compare the use of SOMs for the classification of textual documents in two situations: a conceptual representation of texts and a representation based on n-grams.

Data Services with uncertain and correlated semantics

Currently, a good portion of datasets on Internet are accessed through data services, where user’s queries are answered as a composition of multiple data services. Defining the semantics of data services is the first step towards automating their composition. An interesting approach to define the semantics of data services is by describing them as semantic views over a domain ontology. However, defining such semantic views cannot always be done with certainty, especially when the service’s returned data are too complex. In such case, a data service is associated with several possible semantic views. In addition, complex correlations may be present among these possible semantic views, mainly when data services encapsulate the same data sources. In this paper, we propose a probabilistic approach to model the semantic uncertainty of data services. Services along with their possible semantic views are represented in probabilistic service registry. The correlations among service semantics are modeled through a directed probabilistic graphical model (Bayesian network). Based on our modeling, we study the problem of compositing correlated data services to answer a user query, and propose an efficient method to compute the different possible compositions and their probabilities.

A Reverse Engineering Approach for the Web Service Modeling Ontology Specifications

Semantic Web services (SWS) are the result of the evolution of the syntactic definition of Web services and the semantic Web. Several solutions were proposed for the specification of the semantic web services such as OWL-S (ontology Web language for services) and WSMO (Web service modeling ontology). However, these technologies require a human user intervention to select and choose the required services. We propose an approach to create service ontology with WSMO specifications starting from WSDL (Web service language description) by using the reverse engineering techniques. Reverse engineering aims to extract several types of information of existing software and to employ them for comprehension, renovation as well as maintenance of the system.

Automated migration of data-intensive web pages into ontology-based semantic web: a reverse engineering approach

The advance of the Web has significantly and rapidly changed the way of information organization, sharing and distribution. The next generation of the web, the semantic web, seeks to make information more usable by machines by introducing a more rigorous structure based on ontologies. In this context we try to propose a novel and integrated approach for an automated migration of data-intensive web pages into ontology-based semantic web and thus, make the web content machine-understandable. Our approach is based on the idea that semantics can be extracted from the structures and the instances of database forms which are the most convenient interface to communicate with relational databases on the current Web. This semantics is exploited to help build ontology.

Towards re-engineering Web applications into Semantic Web Services

Semantic Web Services (SWS) are enriching Web services with machine processable semantics. To be implemented with less effort, SWS can reuse syntactic and semantic descriptions hidden under the source code of Web applications already developed. For this end, we propose a framework for reengineering Web applications, possibly already including some semantic technology, into WSMO-based SWS. The proposed framework consists in reverse engineering Web applications towards conceptual models specified with a proposed UML profile, from what syntactic and semantic descriptions of new SWS are generated. A set of tools have been developed and some experiments have been carried out to evaluate and validate the proposed framework.