Contribution à l'apprentissage de la résolution de problèmes scientifiques par la planification (une méthode d'explication basée sur un modèle appelé l'intention de raisonnements)

L apprentissage du raisonnement et de la résolution de problèmes reste un point fondamental dans le cursus des formations des élèves. Cette thèse propose un modèle d apprentissage par l humain du raisonnement appliqué dans le cas résolution problèmes théoriques en physique. L hypothèse de ce travail est inspirée de la théorie constructiviste de l apprentissage. En effet cette théorie avance que l apprentissage n est pas seulement la transmission de la connaissance de l enseignant à l apprenant, il est vu plutôt comme un processus actif de recréation de la connaissance par l apprenant qui apprend en observant, en imitant et en faisant. L entraînement de l apprenant doit être précédé par une bonne compréhension du processus de résolution de problème. Nous proposons d aider l apprentissage de la science physique en utilisant le système Pero que nous avons développé, dans lequel la résolution est basée sur un modèle de résolution auto explicatif. Ce modèle est un planificateur qui permet de résoudre des problèmes mathématiques appliqués aux sciences physiques. Le modèle propose d intégrer la notion de l intention dans le processus de résolution de problèmes afin d ajouter les connaissances d explication de la résolution. Le graphe de résolution dans lequel les nœuds correspondent aux états du planificateur et les arcs aux actions de résolution permet de représenter les explications comme étant le but, les moyens et la justification de résolution au niveau de chaque action. Lors de l apprentissage, les connaissances explicatives sont générées pour permettre à l apprenant de faire les observations nécessaires à leur compréhension avant de reproduire des résolutions similaires. Cette thèse a permis de développer le prototype Pero, dans lequel un module d indexation basé sur une ontologie du domaine a été ajouté pour pouvoir retrouver les exercices déjà résolus. La validation de l approche est faite sur un ensemble d exercices en électricité.Learning the art of reasoning and problem solving is a fundamental part of student training. This thesis proposes a model for the study of reasoning applied to the resolution of theoretical problems in physics. Drawing on constructivist theories of learning, training is presented not so much as the transmission of knowledge from the teacher to the learners but rather as an active process of re-creation of that knowledge by learners who learn by observing, imitating and by doing. Training must be preceded by a thorough understanding of problem solving techniques. We propose to help the study of physics by using a system we have developed called the Pero system. Problem solving is based on a self-explanatory resolution model. This model is a planner that allows solving mathematical problems applied to physics. The model proposes to integrate the notion of intention into the process of resolution in order to add knowledge of problem solving explanations. The resolution graph, in which the nodes correspond to the states of the planner and the curves to the actions of resolution, makes it possible to represent explanations as being the goal, the means and the rationale of resolution at the level of each action. At the time of the training, explanatory knowledge is generated to allow learners to make the observations necessary to promote understanding before reproducing similar resolutions. This thesis lies behind the development of the Pero prototype in which an indexing module based on ontology of the field was added. The indexing module makes it possible to find exercises which have already been solved. The validation of the approach is based on a series of exercises in the field of electricity..TOULOUSE1-BU Arsenal (315552103) / SudocSudocFranceF

Real-time detection of MAC layer misbehavior in mobile ad hoc networks

The MAC layer misbehavior of the IEEE 802.11 standard can have a negative impact on the wireless network’s performance, similar to the effects of denial of service attacks. The goal of this misbehavior was handling the protocol to increase the greedy nodes transmission rate at the expense of the other honest nodes. In fact, nodes in IEEE 802.11 standard should wait for a random backoff interval time to access to the channel before initiating any transmission. Greedy nodes use a malicious technique to reduce the channel waiting time and occupy the channel. This paper introduces a new scheme to detect such malicious behavior, which is based on statistical process control (SPC) borrowed from the industrial field in a quality management context. To the best of our knowledge, this approach has not been proposed in state of the art, reports concerning the detection of greedy behaviors in mobile ad hoc networks. The approach has the power to identify greedy nodes in real time by using a graphical tool called «control chart» that measures the throughput and the inter-packet interval time for each node, and raises an alert if this measure is over a defined threshold. The validation of all obtained results is performed in the network simulator NS2

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally