Convergence des copies dans les environnements collaboratifs répartis

In real time collaborative systems, replicated objects, shared by users, are subject to concurrency constraints. In order to satisfy these, various algorithms, have been proposed that exploit the semantic properties of operations and use Operational transformations to serialize concurrent operations and achieve copy convergence of replicated objects, while preserving users intention. Their drawback is that they either require a condition on user's operations which is hard to verify when possible to ensure, or they need undoing then redoing operations in some situations. The fi rst objective of the thesis is to present two new algorithms that overcome these drawbacks. They are based upon the implementation of a continuous global order which enables that condition to be released, and simpli es the operation integration process. In one of these algorithms, SOCT4 for which we give a formal proof, this process becomes even more simplified thanks to deferred broadcast whereas in the other one, SOCT5, priority is given to concurrency during the broadcast. An extension to these algorithm to support mobile sites is introduced. The second objective is to adapt SOCT2 type algorithms to make it possible for a user to undo an operation insofar as the rare nonrestrictive proposals made to solve this problem compromise in certain cases the convergence of the copies. For that, rather than to handle the opposite operation directly, we consider undo as a speci c operation whose forward transposition must satisfy two general conditions that the study highlights. The reasonableness of this process is validated by the study of critical cases.Dans les environnements collaboratifs répartis temps réel, les objets répliqués, partagés par les utilisateurs sont soumis à des contraintes de concurrence. Pour les satisfaire, différents algorithmes de contrôle, exploitant les propriétés sémantiques des opérations et utilisant les Transformées opérationnelles, ont été proposés de façon à ordonner les opérations concurrentes et par-là garantir la convergence des copies d'un objet tout en respectant l'intention des usagers. Leur inconvénient est d'imposer ou bien que les opérations utilisées par les utilisateurs satisfassent une condition, difficile à vérifier et qu'il n'est pas toujours possible d'assurer, ou bien de défaire puis de refaire des opérations dans certaines situations. Le premier objectif de la thèse est de présenter deux nouveaux algorithmes n'ayant pas ces défauts. Ils reposent sur la mise en œuvre d'un ordre global continu qui permet non seulement de s'affranchir de cette condition mais aussi de simplifier le processus d'intégration d'une opération. Dans l'un des algorithmes, SOCT4 dont nous donnons la preuve formelle, l'intégration est encore simplifiée en différant la diffusion des opérations alors que dans l'autre, SOCT5, le parallélisme dans la diffusion est privilégié. L'extension de ces algorithmes pour tenir compte de la présence de postes mobiles est abordée. Le deuxième objectif est d'adapter les algorithmes de type SOCT2 pour permettre à un utilisateur d'annuler une opération dans la mesure où les rares propositions non restrictives faites pour résoudre ce problème compromettent dans certains cas la convergence des copies. Pour cela, plutôt que de manipuler directement l'opération inverse, on considère l'annulation comme une opération spécifique dont la transposition en avant doit satisfaire deux conditions générales que l'étude met en évidence. Le bien fondé de cette démarche est validée par l'étude de cas critiques

Convergence des copies dans les environnements collaboratifs répartis

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Concurrent Undo Operations in Collaborative Environments using Operational Transformation

International audienceIn distributed collaborative systems, replicated objects, shared by users, are subject to concurrency constraints. All methods [4, 13, 18, 15, 16, 19, 22] proposed to serialize concurrent operations and achieve copies convergence of replicated objects are based on the use of Operational Transformations. In this context, giving the user the ability to undo an operation has been recognized as a difficult problem [1, 2, 3, 12, 14, 20, 21]. The few general propositions to solve the problem sometimes compromise copies convergence and/or users’ intention, insofar as the Operational Transformations used are unsuitable for undo. This paper has a twofold objective. Firstly, it aims to highlight two general conditions (named C3 and C4) that need to be satisfied by any transformation adapted to undo. Secondly, it presents a general undo algorithm based on the definition of a generic undo-fitted transformation, which automatically verifies these conditions. The interest of the proposed method is that the undoing of an operation obeys to the same processing as the one used for regular operations in collaborative systems such as [15,19]

A distributed power management optimisation in wireless sensors networks

This paper presents a study on power management optimisation over a sensor network. We have proposed a set of management rules which are executed by each sensor of the network. These rules adapt themselves to sensors depending on their energy status and on the network energy. Periodically, each sensor computes its rules and decides how to behave (sleeping during a long period or not). An experimentation of these rules has been implemented, we used a distributed sort algorithm on the whole network. We have observed the network behaviour and noticed that the use of these rules allows to increase the average energy life up to 20 %

Copies convergence in a distributed real-time collaborative environment

In real−time collaborative systems, replicated objects, shared by users, are subject to concurrency constraints. In order to satisfy these, various algorithms, qualified as op

Experience of young patients with cancer discussing cannabis with their providers

12061 Background: Although cannabis use among cancer patients to manage cancer treatment-related symptoms continues to grow, little is known about patterns in patient-provider communication regarding cannabis use. We examined demographic differences in cannabis communication among cancer patients and providers at a National Cancer Institute designated cancer center. Methods: We used data of 495 cancer patients via an anonymous electronic survey administered at the University of Miami via REDCap. Participants with consent to contact notations in their electronic medical record were recruited via phone calls and personalized messages in their MyUCHART portal. Self-reported responses on patients' disclosure of cannabis use to healthcare providers and their comfort on discussing cannabis with cancer doctors were analyzed. Age was categorized as: 20-39y, 40-59y and ≥60y. Chi-squared/Fisher’s exact tests and logistic regression analyses were conducted adjusting for age, sex, and ethnicity. Results: The sample was 51.8% male, 39.4% Hispanic, and mean age was 45.9y (SD=15.1) (41.1% were between 20-39y); 43.8% were undergoing treatment and 35.4% were in follow-up/finished treatment. Almost half (45.5%) reported current (past 30-days) cannabis use. Younger (20-39y) patients had higher prevalence of not disclosing cannabis use than older (>60y) patients (36.8% vs 23.9% p<0.01). There were no sex or ethnicity statistical differences. Majority (67.7%) of current cannabis users reported comfort discussing cannabis use with their provider. However, among individuals aged 20-39y, 40.8% reported feeling uncomfortable discussing cannabis with their cancer doctor. In the 40-59y age group, 21.0% expressed discomfort, while only 5.6% of those over 60 years reported similar unease. After adjusting for age, sex, and ethnicity, newly diagnosed cancer patients had lower odds (aOR:0.41, 95% CI:0.17-0.99) of feeling comfortable discussing cannabis use compared to those in follow-up/finished treatment group. Conclusions: Age was a significant factor in disclosing cannabis use to healthcare providers, with disparities noted by age group. These insights highlight the importance of considering age-related factors and treatment status when addressing cannabis use discussions within the oncology setting