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Papers by Claudia Roncancio

Distributed and Parallel Databases, 2004

Proceedings of the 1st French-speaking conference on Mobility and ubiquity computing -, 2004

We present first results on the comparison of transactional commit protocols for mobile context (... more We present first results on the comparison of transactional commit protocols for mobile context (2PC, UCM and CO2PC).

Ingénierie des systèmes d'information, 2005

Cet article décrit nos propositions en matière de transactions mobiles. Nous considérons des envi... more Cet article décrit nos propositions en matière de transactions mobiles. Nous considérons des environnements mobiles composés de diverses unités et gérant des bases de données. Pour nous une transaction mobile est une transaction où l'une des composantes au moins s'exécute sur une unité mobile. Nous décrivons les caractéristiques des environnements mobiles et nous proposons (1) un modèle de transactions mobiles adaptable au contexte d'exécution, le modèle AMT, (2) une étude analytique du modèle AMT qui permet de choisir la meilleure stratégie d'exécution d'une transaction mobile et (3) un intergiciel (TransMobi) comme support du modèle AMT. Nous avons également proposé un protocole spécifique de validation (CO2PC) qui combine une approche optimiste avec un protocole de validation à deux phases. Il autorise une validation optimiste ou non-optimiste des transactions composantes permettant ainsi plus de souplesse dans la validation.

2013 2nd International Conference on Advances in Biomedical Engineering, 2013

ABSTRACT The continuous increasing needs in telemedicine and healthcare, accentuate the need of w... more ABSTRACT The continuous increasing needs in telemedicine and healthcare, accentuate the need of well-adapted medical alert systems. Such alert systems may be used by a variety of patients and medical actors, and should allow monitoring a wide range of medical variables. This paper proposes Tempas, a personalized temporal alert system. It facilitates customized alert configuration by using linguistic trends. The trend detection algorithm is based on data normalization, time series segmentation, and segment classification. It improves state of the art by treating irregular and regular time series in an appropriate way, thanks to the introduction of an observation variable valid time. Alert detection is enriched with quality and applicability measures. They allow a personalized tuning of the system to help reducing false negatives and false positives alerts.

Lecture Notes in Computer Science, 2009

Proceedings 13th International Conference on Data Engineering, 1997

Summary form only given. The Native Active Object System (NAOS) incorporates an active behavior w... more Summary form only given. The Native Active Object System (NAOS) incorporates an active behavior within the object-oriented database management system O2. NAOS rules are event-condition-action (EGA) rules belonging to an O2 database schema. The authors focus on user and temporal event detection as well as composite event detection

Proceedings of the 2014 International C* Conference on Computer Science & Software Engineering - C3S2E '14, 2008

The RS2.7 Replication Framework revisits the replication function in order to provide a component... more The RS2.7 Replication Framework revisits the replication function in order to provide a component-based middleware support that can adapt to several kind of environment. It clearly identifies what minimal functions are relevant to replication: binding replicas between themselves, and synchronizing them in order to support the right levels of coherency. This paper focuses on the coherency issue. We analyse how this feature can be decomposed with respect to two dimensions: functional and scheduling. Playing with these two dimensions allows to provide different replication solutions by merely assembling RS2.7 components. A prototype of RS2.7 is operational and has been applied to a platform for interactive networked applications. RÉSUMÉ. RS2.7 est un Canevas de Duplication redéfinissant la fonctionnalité de duplication, afin de fournir un intergiciel à base de composants pouvant s'adapter à différents environnements. Il identifie les fonctions minimales propres à la duplication : la liaison entre les copies et leur synchronisation afin d'obtenir la cohérence locale souhaitée. Ce papier se focalise sur les problèmes de cohérence. Nous analysons comment cette caractéristique peut se décomposer selon deux dimensions : fonctionnelle et structurelle. En jouant avec ces deux dimensions, il est possible de fournir différentes solutions gérant la duplication en assemblant simplement des composants conformes à RS2.7. Un prototype de RS2.7 est opérationnel et a été utilisé dans une plate-forme pour applications interactives en réseau.

isima.fr

Les caches sont traditionnellement utilisés pour optimiser les performances et sont souvent intim... more Les caches sont traditionnellement utilisés pour optimiser les performances et sont souvent intimement liés aux applications ce qui les rend peu réutilisables et augmentent donc leur coût de conception. Nous proposons Adaptable Cache Service (ACS) un canevas logiciel pour la création de caches adaptables. Nous l'avons validé dans un intergiciel de données sur grille sous la forme d'un Cache Dual qui, suivant une approche sémantique, combine des caches de requêtes et d'objets, tous deux instances de ACS, qui coopèrent pour maximiser les performances.

Concurrency and Computation: Practice and Experience, 2009

Caching is an important element to tackle performance issues in largely distributed data manageme... more Caching is an important element to tackle performance issues in largely distributed data management. However, caches are efficient only if they are well configured according to the context of use. As a consequence, they are usually built from scratch. Such an approach appears to be expensive and time consuming in grids where the various characteristics lead to many heterogeneous cache requirements. This paper proposes a framework facilitating the construction of sophisticated and dynamically adaptable caches for heterogeneous applications. Such a framework has enabled the evaluation of several configurations for distributed data querying systems and leads us to propose innovative approaches for semantic and cooperative caching. This paper also reports the results obtained in bioinformatics data management on grids showing the relevance of our proposals.

… de computacion de …, 2007

Caching is crucial to improve performances in many computing systems. This work proposes a cachin... more Caching is crucial to improve performances in many computing systems. This work proposes a caching approach for improving query evaluation. The proposed solution follows a semantic oriented approach and combines query and object caching. Separating query and objects provides high flexibility, by making possible to use several cooperations between caches and by supplying different query management tools. Our proposition has been experimented in a grid data management middleware and seems promising as showed by the results reported in this paper.

In recent years data management in mobile environments has generated a great interest. Several pr... more In recent years data management in mobile environments has generated a great interest. Several proposals concerning mobile transactions have been done, however, it is very di cult to have an overview of all these approaches. In this paper we analyze and compare some proposals, we focus on the e ect of mobile transactions on the ACID properties and on the execution model. In addition, we analyze approaches that deal particularly with the mobile nature of mobile hosts; in these proposals the ACID properties are not compromised because transactions are executed at multidatabase systems on the wired network. Based on our analysis, we introduce our ongoing research: the de nition, design and implementation of a Mobile Transaction Service.

Journées Bases de Données Avancées, 2001

Mobile Transaction Supports for DBMS Patricia Serrano-Alvarado1, Claudia L. Roncancio, Michel E. ... more Mobile Transaction Supports for DBMS Patricia Serrano-Alvarado1, Claudia L. Roncancio, Michel E. Adiba LSR-IMAG Laboratory, BP 72, 38402 St-Martin d'H`eres, France E-mail: Firstname.Lastname@imag.fr ... In Prewrite, neither reconciliation nor re-execution are made. ...

Computer Systems …, 2005

Mobile environments are characterized by high variability (e.g. variable bandwidth, disconnection... more Mobile environments are characterized by high variability (e.g. variable bandwidth, disconnections, different communication prices) as well as by limited mobile host resources. Such characteristics lead to high rates of transaction failures and variable execution costs. To raise the success rate of transactions and to have a minimal control on resources consumption we claim that both application design and transaction management should be environment aware. This paper proposes an Adaptable Mobile Transaction model (AMT) that allows defining transactions with several execution alternatives associated to a particular context. When an AMT is launched, the appropriate execution alternative is initiated depending on the current environment state. The goal is to adapt transaction execution to context variations. Our model relaxes atomicity and isolation properties but preserves conflict-serializability. A specification of the AMT model in ACTA (formalism based on the first order logic) is presented. An analytical study shows that using AMTs increases commit probabilities and that it is possible to choose the way transactions will be executed according to their costs.