Jamel Feki

AN AUTOMATIC METHOD FOR THE DESIGN OF MULTIDIMENSIONAL SCHEMAS FROM OBJECT ORIENTED DATABASES

A data warehouse (DW) is a large data repository system designed for decision-making purposes. Its design relies on a specific model called multidimensional. This multidimensional model supports analyses of huge volumes of data that trace the enterprises activities over time. Several design methods were proposed to build multidimensional schemas from either the relational data model or the entity-relationship data model. Almost all proposals that treated the object-oriented data model assume the presence of the data source UML class-diagram. However, in practice, either such a diagram does not exist or is obsolete due to multiple changes/evolutions of the information system. Furthermore, these few proposals require an intense manual intervention of the designer, which requires a high expertise both in the DW domain and in the object database domain. To overcome these disadvantages, this work proposes an automatic DW schema design method starting from an object database (schema and its instances). This method applies a set of extraction rules to identify multidimensional concepts and to generate star schemas. It is defined for the standard ODMG model and, thus, can be adapted with slight changes for other object database models. In addition, its extraction rules have the merit of being independent of the domain semantics. Furthermore, they automatically generate schemas classified according to their analytical potential; this classification helps the DW designer in selecting the most relevant schemas among the generated ones. Finally, being automatic, our method is supported by a toolset that also prepares for the automatic generation of the Extract Transform and Load procedures used to load the DW.

Building an XML document warehouse

Abstract Data Warehouses and OLAP (On Line Analytical Processing) technologies are dedicated to analyzing structured data issued from organizations’ OLTP (On Line Transaction Processing) systems. Furthermore, in order to enhance their decision support systems, these organizations need to explore XML (eXtensible Markup Language) documents as an additional and important source of unstructured data. In this context, this paper addresses the warehousing of document-centric XML documents. More specifically, we propose a two-method approach to build Document Warehouse conceptual schemas. The first method is for the unification of XML document structures; it aims to elaborate a global and generic view for a set of XML documents belonging to the same domain. The second method is for designing multidimensional galaxy schemas for Document Warehouses.

Conception assistée de MD : Une démarche et un outil

To assist the decisional designer in building data mart star schemes relying on a relational data source, we propose an approach supported by a tool. Our approach is independent of the semantic of any source information system; it classifies the relations in Rentities and R-associations and, is based on the structural semantics of the relations which is disseminated through the primary keys and referential constraints. This approach extracts facts, dimensions and hierarchies using a set of appropriate heuristics. A software tool baptized CAME is developed to support our proposed method; it constructs automatically star scheme data marts.

Manifestations ophtalmologiques de la hyalinose cutanéo-muqueuse

Resume Introduction La hyalinose cutaneo-muqueuse (HCM) ou lipoproteinose d’Urbach-Wiethe est une affection rare a transmission autosomique recessive. Elle est caracterisee par un depot d’une substance hyaline au niveau de la peau et des muqueuses. Les manifestations ophtalmologiques sont frequentes pouvant conditionner le pronostic visuel. Observation Il s’agit d’une patiente âgee de 28 ans qui a eu des lesions vesiculo-bulleuses de la face evoluant vers des cicatrices varioliformes associees a un raucite de la voix. Elle avait une atteinte oculaire unilaterale gauche sous forme d’un depot hyalin limbique, irien et trabeculaire qui s’est complique d’une uveite, d’une cataracte et d’un glaucome ayant entraine la perte fonctionnelle de l’œil. L’etude histologique d’une biopsie cutanee concluait a une hyalinose cutaneo-muqueuse. Discussion L’atteinte palpebrale au cours de la hyalinose cutaneo-muqueuse est classique particulierement la blepharose moniliforme qui est pathognomonique. Ce cas se caracterisait par une atteinte intra-oculaire rare a type d’uveite. Par ailleurs, on peut trouver des depots corneo-conjonctivaux, trabeculaires ou au niveau de la membrane de Bruch. L’examen histologique des biopsies cutanee et/ou conjonctivale confirme le diagnostic. Les moyens therapeutiques sont assez limites.

Modélisation multidimensionnelle de documents XML centrés-données

Today’s international nature of commerce forced the opening of corporal information systems (IS) to accept data required for both transactional and decisional processes. To ensure the interoperability of so opened IS, XML has been adopted as a de facto standard format for exchanged data. In order to accommodate this data format in the design of decision support systems, we propose in this paper an automatic method for the design of data mart schemas from XML documents. The proposed method has the merit of automatically identifying all multidimensional elements, classifying them in terms of their analytical potential, and tracing them to the source which facilitates the definition of ETL procedures. For this, our method analyzes the DTD of the source documents and consults a sample of XML documents to determine typing information when needed. It relies on a set of identification rules that are independent of the domain of the XML documents. Furthermore, being automatic, it is supported by a CASE toolset that facilitates its exploitation.

Toward evolution models for data warehouses

A Data warehouse (DW) is characterized by a complex architecture, designed in order to integrate data derived from operational data sources (DS), hence providing advanced analytical tools of these data. The DW is highly dependent on its DS. Hence, evolutions of the DS schema need to be propagated to the DW schema and content. This paper presents a model-driven approach for the evolution of a multidimensional DW. It is based on two evolution models: a first evolution model for the DS and another for the DW. These two models concern the data structure aspects as well as the evolution operations. The transition between these two models is performed through specific transformation rules defined in QVT (Query\View\Transformation).

Visual Loss Associated with Rickettsial Disease

Abstract Purpose: To characterize and analyze ocular involvement associated with visual loss in a cohort of patients with rickettsial disease. Methods: Retrospective study of 16 eyes of 14 patients. Results: Mean initial visual acuity (VA) was 20/63 (range, 20/800–20/25). White retinal lesions infiltrating inner retina was the most common finding occurring in 14 eyes (87.5%). It was associated with a serous retinal detachment (SRD), accurately detectable by optical coherence tomography, in 11 eyes (78.6%). Other findings included optic neuropathy in 7 eyes (43.75%), cystoid macular edema in 1 eye (6.25%), branch retinal artery occlusion in 1 eye (6.25%), and choroidal neovascularization in 1 eye (6.25%). Thirteen patients were treated with a 2-week course of oral doxycycline 200 mg/day. Mean final VA was 20/40. Conclusions: Inner retinitis, associated with mild vitritis and SRD, and optic neuropathy are the most common vision-threatening ocular manifestations of rickettsial disease.

Diamond multidimensional model and aggregation operators for document OLAP

On-Line Analytical Processing (OLAP) has generated methodologies for the analysis of structured data. However, they are not appropriate to handle document content analysis. Because of the fast growing of this type of data, there is a need for new approaches abling to manage textual content of data. Generally, these data exist in XML format. In this context, we propose an approach of construction of our Diamond multidimensional model, which includes semantic dimension to better consider the semantics of textual data In addition, we propose new aggregation operators for textual data in OLAP environment.

Metamodel matching techniques evaluation and benchmarking

During the last decades, the matching operation has been thoroughly studied in database systems and ontology development. Matching is critical in many application domains such as semantic web, schema and data integration, data translation. In the Model Driven Engineering (MDE) context, matching techniques between two metamodels are the centerpiece of a semi-automatic transformation process. Metamodel matching allows discovering mappings between two metamodels and then generating transformation rules. In this paper, we propose an approach for metamodel matching techniques evaluation and benchmarking. This approach firstly provides a benchmark for metamodel matching and, secondly prepares to semi-automate the transformation process according to the Model Driven Architecture (MDA). A benchmark is useful to compare the strengths and weaknesses of different metamodel matching techniques. Experimental results comparing the effectiveness of the application of various implementations of four recent techniques (Similarity Flooding, ModeICVS, SAMT4MDE andAML) on real-world metamodels are given.

A first step for building a document warehouse: Unification of XML documents

The Web plays a key role for information publication and exchange between organizations. In this context, the XML format becomes a common standard for data representation and exchange. On the other hand, XML documents constitute an important source for decisional analyses since they help decision makers to better understand and control the evolution of their business processes. However, even though several XML documents may belong to a same domain, they may be described by multiple structures. In this paper, we present a method to unify XML document structures in order to build a global and generic perception/view of heterogeneous documents, to store them as a document warehouse, and finally, to query them easily. We also describe our software prototype USD (Unification of Structures of XML Documents) which supports the proposed method. We illustrate its functionalities through an example.