Modélisation et manipulation de données historisées et archivées dans un entrepôt orienté objet

National audienceThis paper deals with temporal and archive object-oriented data warehouse modelling and querying. In a first step, we define a data model describing warehouses as central repositories of complex and temporal data extracted from one information source. The model is based on the concepts of warehouse object and environment. A warehouse object is composed of one current state, several past states (modelling value changes) and several archive states (summarising some value changes). An environment defines temporal parts in a warehouse schema according to a relevant granularity (attribute, class or graph). In a second step, we provide a query algebra dedicated to data warehouses. This algebra, which is based on common object algebras, integrates temporal operators and operators for querying object states. An other important contribution concerns dedicated operators allowing users to transform warehouse objects in temporal series as well as operators facilitating analytical treatments

Elaboration d'entrepôts de données complexes

National audienceIn this paper, we study the data warehouse modelling used in decision support systems. We provide an object-oriented data warehouse model allowing data warehouse description as a central repository of relevant, complex and temporal data. Our model integrates three concepts such as warehouse object, environment and warehouse class. Each warehouse object is composed of one current state, several past states (modelling its detailed evolutions) and several archive states (modelling its evolutions within a summarised form). The environment concept defines temporal parts in the data warehouse schema with significant granularities (attribute, class, graph). Finally, we provide five functions aiming at defining the data warehouse structures and two functions allowing the warehouse class inheritance hierarchy organisation

Modélisation et extraction de données pour un entrepôt objet

National audienceThis paper describes an object-oriented model for designing complex and time-variant data warehouse data. The main contribution is the warehouse class concept, which extends the class concept by temporal and archive filters as well as a mapping function. Filters allow the keeping of relevant data changes whereas the mapping function defines the warehouse class schema from a global data source schema. The approach take into account static properties as well as dynamic properties. The behaviour extraction is based on the use-matrix concept

Managing complex taxonomic data in an object-oriented database.

This thesis addresses the problem of multiple overlapping classifications in object-oriented databases through the example of plant taxonomy. These multiple overlapping classifications are independent simple classifications that share information (nodes and leaves), therefore overlap. Plant taxonomy was chosen as the motivational application domain because taxonomic classifications are especially complex and have changed over long periods of time, therefore overlap in a significant manner. This work extracts basic requirements for the support of multiple overlapping classifications in general, and in the context of plant taxonomy in particular. These requirements form the basis on which a prototype is defmed and built. The prototype, an extended object-oriented database, is extended from an object-oriented model based on ODMG through the provision of a relationship management mechanism. These relationships form the main feature used to build classifications. This emphasis on relationships allows the description of classifications orthogonal to the classified data (for reuse and integration of the mechanism with existing databases and for classification of non co-operating data), and allows an easier and more powerful management of semantic data (both within and without a classification). Additional mechanisms such as integrity constraints are investigated and implemented. Finally, the implementation of the prototype is presented and is evaluated, from the point of view of both usability and expressiveness (using plant taxonomy as an application), and its performance as a database system. This evaluation shows that the prototype meets the needs of taxonomists

Methodologies for distributed and higher dimensional geographic information

PhD ThesisIn today's digital era, cartography has changed its role, from that of a pure visual model of the Earth's surface, to an interface to other spatial and aspatial information. Along with this, representationa nd manipulation of graphical information in three-dimensional space is required for many applications. Problems and difficulties must be overcome in order to facilitate the move to three-dimensional models, multimedia, and distributed data. Can accurate measurements, at sufficient resolution, and using affordable resources be obtained? Will application software usefully process, in all aspects, models of the real world, sounds, and videos? Combined with this, the workplace is becoming distributed, requiring applications and data that can be used across the globe as easily as in the office. A distributed, three-dimensional, GIS is required with all the procedural and recording functionality of current two-dimensional systems. Such a GIS would maintain a model, typically comprised of solids of individual buildings, roads, utilities etc. with both external and internal detail, represented on a suitable digital terrain model. This research examines virtual reality software as part of an answer. Alternatively, can technologies such as HTML, VRML, and scripting, along with object-orientation and open systems, allow for the display and interrogation of networked data sets? The particular application of this technology, considered during this research, is the need for accurate reconstruction of historical urban monuments. The construction, manipulation, and exploration of these models is often referred to as virtual heritage. This research constructs an innovative and resource effective methodology, the Phoenix algorithm, which requires only a single image for creating three-dimensional models of buildings at large scale. The development of this algorithm is discussed and the results obtained from it are compared with those obtained using traditional three-dimensional capture techniques. Furthermore, possible solutions to the earlier questions are given and discussed