Bipolar SQLf: a Flexible Querying Language for Relational Databases

International audienceFlexible querying of information systems allows expressing complex preferences in user queries. Such preferences can be modeled by fuzzy bipolar conditions which are made of constraints c and wishes w and interpreted as "to satisfy c and if possible to satisfy w".We de ne in this article the main elements of the Bipolar SQLf language, which is an SQL-like querying language based on a bipolar relational algebra. This language is an extension of the SQLf language. Basic statements (projection, selection, etc.) are firstly defined in terms of syntax, evaluation and calibration. Then, complex statements, such as bipolar queries based on nesting operators are studied in terms of expression, evaluation, query equivalence and backward compatibility with the SQLf language

Evaluation of Quantified Statements using Gradual Numbers - 64

Dr. Ludovic Liétard is currently assistant professor at the University of Rennes 1 (IUT Lannion) in France. His research mainly concerns flexible querying of relational databases using fuzzy set theory and various applications of fuzzy set theory in databases. Dr. Daniel Rocacher is currently assistant professor at the University of Rennes 1 (ENSSAT Lannion) in France. He has proposed new directions to define gradual numbers in the framework of fuzzy set theory. His current research concerns their applications in databases. Evaluation of Quantified Statements using Gradual Numbers -2 -Abstract. This paper is devoted to the evaluation of quantified statements which can be found in many applications as decision-making, expert systems or flexible querying of relational databases using fuzzy set theory. Its contribution is to introduce the main techniques to evaluate such statements and to propose a new theoretical background for the evaluation of quantified statements of type "Q X are A" and "Q B X are A". In this context, quantified statements are interpreted using an arithmetic on gradual numbers from ℕ f , ℤ f and ℚ f . It is shown that the context of fuzzy numbers provides a framework to unify previous approaches and can be the base for the definition of new approaches

Contribution à l'interrogation flexible et personnalisée d'objets complexes modélisés par des graphes

Plusieurs domaines d'application traitent des objets et des données complexes dont la structure et la sémantique de leurs composants sont des informations importantes pour leur manipulation et leur exploitation. La structure de graphe a été bien souvent adoptée, comme modèles de représentation, dans ces domaines. Elle permet de véhiculer un maximum d'informations, liées à la structure, la sémantique et au comportement de ces objets, nécessaires pour assurer une meilleure représentation et une manipulation e cace. Ainsi, lors d'une comparaison entre deux objets complexes, l'opération d'appariement est appliquée entre les graphes les modélisant. Nous nous sommes intéressés dans cette thèse à l'appariement approximatif qui permet de sélectionner les graphes les plus similaires au graphe d'une requête. L'objectif de notre travail est de contribuer à l'interrogation exible et personnalisée d'objets complexes modélisés sous forme de graphes pour identi er les graphes les plus pertinents aux besoins de l'utilisateur, exprimés d'une manière partielle ou imprécise. Dans un premier temps, nous avons proposé un cadre de sélection de services Web modélisés sous forme de graphes qui permet (i) d'améliorer le processus d'appariement en intégrant les préférences des utilisateurs et l'aspect structurel des graphes comparés, et (ii) de retourner les services les plus pertinents. Une deuxième méthode d'évaluation de requêtes de recherche de graphes par similarité a également été présentée pour calculer le skyline de graphes d'une requête utilisateur en tenant compte de plusieurs mesures de distance de graphes. En n, des approches de ra nement ont été dé nies pour réduire la taille, souvent importante, du skyline. Elles ont pour but d'identi er et d'ordonner les points skyline qui répondent le mieux à la requête de l'utilisateur.Several application domains deal with complex objects whose structure and semantics of their components are crucial for their handling. For this, graph structure has been adopted, as a model of representation, in these areas to capture a maximum of information, related to the structure, semantics and behavior of such objects, necessary for e ective representation and processing. Thus, when comparing two complex objects, a matching technique is applied between their graph structures. In this thesis, we are interested in approximate matching techniques which constitute suitable tools to automatically nd and select the most similar graphs to user graph query. The aim of our work is to develop methods to personalized and exible querying of repositories of complex objects modeled thanks to graphs and then to return the graphs results that t best the users needs, often expressed partially and in an imprecise way. In a rst time, we propose a exible approach for Web service retrieval that relies both on preference satis ability and structural similarity between process model graphs. This approach allows (i) to improve the matching process by integrating user preferences and the graph structural aspect, and (ii) to return the most relevant services. A second method for evaluating graph similarity queries is also presented. It retrieves graph similarity skyline of a user query by considering a vector of several graph distance measures instead of a single measure. Thus, graphs which are maximally similar to graph query are returned in an ordered way. Finally, re nement methods have been developed to reduce the size of the skyline when it is of a signi cant size. They aim to identify and order skyline points that match best the user query.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF

Fuzzy Bipolar Conditions of Type "or else"

International audiencePreviously studied fuzzy bipolar conditions of type "and if possible" are made of a mandatory condition c and an optional condition w. They allow expressing complex preferences of a conjunctive nature. We define in this paper, a new kind of fuzzy bipolar conditions of the form "or else" which express complex preferences of a disjunctive nature. We show that the "or else" form can be used as a negation operator of the "and if possible" form and vice versa. We also show that these both forms are compatible and, therefore, fuzzy bipolar conditions of both types can be used together in the same bipolar query

An Extension of a Fuzzy Ontology for Flexible Querying

International audienceIn this paper, we propose a personalized approach for flexible querying of information systems. This approach consists in the combination of the reasoning capabilities of the fuzzy DLR-Lite ontology and the expressivity of the SQLf language. The interpretation of the gradual inclusion (subsumption) axioms of the ontology is based on the G¨odel fuzzy implication. Its generalization to a tree of inclusions is also proposed. This tree and its property of propagation of degrees are the basic theoretical elements of our application, which consists in querying of a multimodal transport information system which is embedded in a mobile terminal characterized by limited storage and processing capabilities

Etude d'une architecture dirigee par les donnees appliquee au langage ADA

SIGLECNRS T 57255 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Interrogation personnalisée des systèmes d'information dédiés au transport (une approche bipolaire floue)

Les applications actuellement disponibles de recherche d itinéraires dans les réseaux detransport collectif ne permettent qu une recherche circonscrite à une seule offre detransport (transport urbain, aérien, ferroviaire, maritime, etc.). L utilisateur est mis face à une profusion de données dont il n est pas aisé de distinguer les informations pertinentes des informations inutiles. Dans ce contexte, les préférences utilisateur sont considérées pour la recherche du meilleur itinéraire. Nous modélisons ces préférences à l aide de conditions bipolaires floues associant des conditions d acceptation et des conditions d optimalité. Ces préférences sont exprimées dans un cadre relationnel composé d une algèbre relationnelle bipolaire et d un langage d interrogation : le SQLf bipolaire. Les préférences utilisateur jouent dans notre approche le rôle de filtre initial des données, que nous combinons à une logique de description étendues aux relations m-aires et aux conditions bipolaires floues, afin de cibler les meilleurs sous-ensembles de données à même de répondre efficacement aux requêtes de l utilisateur. Nous proposons dans cette thèse une approche d interrogation personnalisée des systèmes d information dédiés au transport, qui associe des préférences bipolaires floues et des ontologies. Le but étant de fournir aux usagers un moyen de combiner d une manière automatique, flexible et personnalisée, les différents services de transport disponibles pour effectuer leurs déplacements. Les résultats préliminaires obtenus illustrent le fort potentiel de notre démarche pour le développement d un nouveau type de services personnalisés destinés aux usagers des réseaux de transport.Today s web applications dedicated to trip planning are mainly limited to only one kind of transport service (urban transport, air transport, transport by rail and sea, etc.). The user is then compelled to build manually his/her trip by combining available transport services. This querying can lead to process huge volumes of data, and can deliver massive responses, in which it is difficult to the user to distinguish the relevant answers from irrelevant ones. In this context, user preferences are considered in the process of retrieval of the best trip. In our case, user preferences are modelled by fuzzy bipolar conditions which associate essential preferences (very important preferences), and minor preferences (less important preferences), and expressed within a relational framework based on a bipolar relational algebra and a relational query language called bipolar SQLf. User preferences play the role of data screening, which we combine to a reasoning mechanism made of a description logic extended to m-ary relations and fuzzy bipolar conditions, so that only the most relevant data is targeted to evaluate user queries. We introduce in this thesis, a new approach for personalized querying of information systems dedicated to multimodal transport network, based on fuzzy bipolar preferences and ontologies. The objective is to provide users with means to combine automatically, in personalized and flexible way, several transport networks in order to plan their preferred trips. Preliminary results point out the potentialities of our approach in the development of new kind of personalized user services.LANNION-ENSSAT (221132206) / SudocSudocFranceF

Ontology-Based Evaluation of Fuzzy Bipolar Conjunctive Queries over Relational Databases

In the wake of flexible querying system, proposed in [26], [28], [29], in which the bipolarity of the form "and if possible" is used as means to express user preferences over relational databases and ontologies (fuzzy bipolar DLR-Lite), we introduce in this paper the user query evaluation process, under the extension of our flexible querying framework to bipolar conditions of the form "or else" [20], [19]. Queries addressed to our system are bipolar conjunctive queries made of a conjunction of atoms corresponding to concepts of an ontology. The proposed evaluation process is carried out in two main steps. The former consists of query derivation to compute complementary queries, based on substitutions of query's atoms involved in fuzzy bipolar subsumptions expressed in the considered bipolar ontology. The latter deals with the translation of the obtained set of queries from the first step into bipolar SQLf statements, which are finally evaluated over a bipolar relational database managed by PostgreSQLf DBMS extended to bipolar datatypes and functions. Three algorithms are then developed in order to perform applicable substitutions, to derive corresponding complementary queries and to translate them into Bipolar SQLf statements. The feasibility of the approach is shown through a prototype developed in the field of multimodal transport systems