9 research outputs found

    A Reinforcement Learning Method For An Autonomous Robot

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    This paper presents a fuzzy navigation system for an autonomous robot. A behavior-based control system provides the robot with the adaptibility necessary for coping with a dynamically changing environment. Moreover, a reinforcement learning method is used for on-line rule optimization. keywords: Fuzzy Logic, obstacle avoidance, wall-following, reinforcement learning, on-line optimization. 1 Introduction Many manufacturing systems require autonomous robots capable of coping with dynamically changing unknown environments: transport of parts from one place to another, removing any undesired objects from floors, surveillance, and so on. Traditional methods have met great difficulties in application to realtime problems. They often require large computational power and memory, incompatible with embedded systems and real-time requirements. On the other hand, reactive or behavior-based systems offer an interesting alternative and have two main advantages: ffl prior knowledge can be easily..

    Bayesian predictive model to assess BRCA2 mutational status according to clinical history: Early onset, metastatic phenotype or family history of breast/ovary cancer

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    International audienceBackground: Mutations of the BRCA2 gene are the most frequent alterations found in germline DNA from men with prostate cancer (PrCa), but clinical parameters that could better orientate for BRCA2 mutation screening need to be established.Methods: Germline DNA from 325 PrCa patients (median age at diagnosis: 57 years old) was screened for BRCA2 mutation. The mutation frequency was compared between three subgroups: patients with an age at diagnosis at 55 years old and under (Group I); a personal or family history of breast, uterine or ovarian cancer (Group II); or a metastatic disease (Group III). Frequency of BRCA2 mutations was established for each combination of phenotypes, and compared between patients meeting or not the criteria for each subgroup using Fisher's exact test. Mutual information, direct effect, elasticity and contribution to the mutational status of each phenotype, taking into account overlap between subgroups, were also estimated using Bayesian algorithms.Results: The proportion of BRCA2 mutation was 5.9% in Group I, 10.9% in Group II and 6.9% in Group III. The frequency of BRCA2 mutation was significantly higher among patients of Group II (p = .006), and reached 15.6% among patients of this group who presented a metastatic disease. Mutual information, direct effect, elasticity and contribution to the mutational status were the highest for phenotype II. Fifteen (71.4%) of the 21 BRCA2 mutation carriers had an aggressive form of the disease. Four (19%) of them died from PrCa after a median follow-up duration of 64.5 months.Conclusions: Our results showed that a higher frequency of BRCA2 mutation carriers is observed, not only among PrCa patients with young onset or a metastatic disease, but also with a personal or a familial history of breast cancer

    Predictive accuracy of covid-19 world health organization (Who) severity classification and comparison with a bayesian-method-based severity score (epi-score)

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    International audienceObjectives: Assess the predictive accuracy of the WHO COVID-19 severity classification on COVID-19 hospitalized patients. The secondary aim was to compare its predictive power with a new prediction model, named COVID-19 EPI-SCORE, based on a Bayesian network analysis. Methods: We retrospectively analyzed a population of 295 COVID-19 RT-PCR positive patients hospitalized at Epicura Hospital Center, Belgium, admitted between March 1st and April 30th, 2020. Results: Our cohort’s median age was 73 (62–83) years, and the female proportion was 43%. All patients were classified following WHO severity classification at admission. In total, 125 (42.4%) were classified as Moderate, 69 (23.4%) as Severe, and 101 (34.2%) as Critical. Death proportions through these three classes were 11.2%, 33.3%, and 67.3%, respectively, and the proportions of critically ill patients (dead or needed Invasive Mechanical Ventilation) were 11.2%, 34.8%, and 83.2%, respectively. A Bayesian network analysis was used to create a model to analyze predictive accuracy of the WHO severity classification and to create the EPI-SCORE. The six variables that have been automatically selected by our machine learning algorithm were the WHO severity classification, acute kidney injury, age, Lactate Dehydrogenase Levels (LDH), lymphocytes and activated prothrombin time (aPTT). Receiver Operation Characteristic (ROC) curve indexes hereby obtained were 83.8% and 91% for the models based on WHO classification only and our EPI-SCORE, respectively. Conclusions: Our study shows that the WHO severity classification is reliable in predicting a severe outcome among COVID-19 patients. The addition to this classification of a few clinical and laboratory variables as per our COVID-19 EPI-SCORE has demonstrated to significantly increase its accuracy

    Prevalence and 6-month recovery of olfactory dysfunction: a multicentre study of 1363 COVID-19 patients

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    International audienceObjective: To investigate prevalence and recovery of olfactory dysfunction (OD) in COVID-19 patients according to the disease severity. Methods: From 22 March to 3 June 2020, 2581 COVID-19 patients were identified from 18 European hospitals. Epidemiological and clinical data were extracted at baseline and within the 2-month post-infection. Results: The prevalence of OD was significantly higher in mild form (85.9%) compared with moderate-to-critical forms (4.5–6.9%; P = 0.001). Of the 1916 patients with OD, 1363 completed the evaluations (71.1%). A total of 328 patients (24.1%) did not subjectively recover olfaction 60 days after the onset of the dysfunction. The mean duration of self-reported OD was 21.6 ± 17.9 days. Objective olfactory evaluations identified hyposmia/anosmia in 54.7% and 36.6% of mild and moderate-to-critical forms, respectively (P = 0.001). At 60 days and 6 months, 15.3% and 4.7% of anosmic/hyposmic patients did not objectively recover olfaction, respectively. The higher baseline severity of objective olfactory evaluations was strongly predictive of persistent OD (P < 0.001). Conclusion: OD is more prevalent in mild COVID-19 forms than in moderate-to-critical forms. OD disappeared in 95% of patients regarding objective olfactory evaluations at 6 months

    Features of Mild-to-Moderate COVID-19 Patients With Dysphonia

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    International audienceIntroduction: To explore the prevalence of dysphonia in European patients with mild-to-moderate COVID-19 and the clinical features of dysphonic patients.Methods: The clinical and epidemiological data of 702 patients with mild-to-moderate COVID-19 were collected from 19 European Hospitals. The following data were extracted: age, sex, ethnicity, tobacco consumption, comorbidities, general, and otolaryngological symptoms. Dysphonia and otolaryngological symptoms were self-assessed through a 4-point scale. The prevalence of dysphonia, as part of the COVID-19 symptoms, was assessed. The outcomes were compared between dysphonic and nondysphonic patients. The association between dysphonia severity and outcomes was studied through Bayesian analysis.Results: A total of 188 patients were dysphonic, accounting for 26.8% of cases. Females developed more frequently dysphonia than males (P = 0.022). The proportion of smokers was significantly higher in the dysphonic group (P = 0.042). The prevalence of the following symptoms was higher in dysphonic patients compared with nondysphonic patients: cough, chest pain, sticky sputum, arthralgia, diarrhea, headache, fatigue, nausea, and vomiting. The severity of dyspnea, dysphagia, ear pain, face pain, throat pain, and nasal obstruction was higher in dysphonic group compared with nondysphonic group. There were significant associations between the severity of dysphonia, dysphagia, and cough.Conclusion: Dysphonia may be encountered in a quarter of patients with mild-to-moderate COVID-19 and should be considered as a symptom list of the infection. Dysphonic COVID-19 patients are more symptomatic than nondysphonic individuals. Future studies are needed to investigate the relevance of dysphonia in the COVID-19 clinical presentation

    Clinical and epidemiological characteristics of 1420 European patients with mild-to-moderate coronavirus disease 2019

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    International audienceBackground: The clinical presentation of European patients with mild-to-moderate COVID-19 infection is still unknown. Objective: To study the clinical presentation of COVID-19 in Europe. Methods: Patients with positive diagnosis of COVID-19 were recruited from 18 European hospitals. Epidemiological and clinical data were obtained through a standardized questionnaire. Bayesian analysis was used for analysing the relationship between outcomes. Results: A total of 1,420 patients completed the study (962 females, 30.7% of healthcare workers). The mean age of patients was 39.17 ± 12.09 years. The most common symptoms were headache (70.3%), loss of smell (70.2%), nasal obstruction (67.8%), cough (63.2%), asthenia (63.3%), myalgia (62.5%), rhinorrhea (60.1%), gustatory dysfunction (54.2%) and sore throat (52.9%). Fever was reported by 45.4%. The mean duration of COVID-19 symptoms of mild-to-moderate cured patients was 11.5 ± 5.7 days. The prevalence of symptoms significantly varied according to age and sex. Young patients more frequently had ear, nose and throat complaints, whereas elderly individuals often presented fever, fatigue and loss of appetite. Loss of smell, headache, nasal obstruction and fatigue were more prevalent in female patients. The loss of smell was a key symptom of mild-to-moderate COVID-19 patients and was not associated with nasal obstruction and rhinorrhea. Loss of smell persisted at least 7 days after the disease in 37.5% of cured patients. Conclusion: The clinical presentation of mild-to-moderate COVID-19 substantially varies according to the age and the sex characteristics of patients. Olfactory dysfunction seems to be an important underestimated symptom of mild-to-moderate COVID-19 that needs to be recognized as such by the WHO

    Sociologie de l'énergie

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    Affaire de société, enjeu politique, objet de controverses, l'énergie est devenue depuis une quinzaine d'années un sujet de recherche de première importance pour les sociologues. Alors que les débats autour de la transition énergétique s'animent, ce livre réunit les analyses scientifiques de chercheurs issus d'horizons institutionnels différents. L'objectif est de mutualiser, en un seul ouvrage et pour la première fois, les connaissances et les approches théoriques quant à la gouvernance de l'action publique et aux pratiques sociales dans le domaine de l'énergie. L'ouvrage s'organise autour de six parties. La première est consacrée aux approches conceptuelles et théoriques. Cette partie insiste sur les changements en termes d'action publique, et les reconfigurations qu'implique le choix d'une société bas carbone. La seconde partie traite des conditions et des instruments de la gouvernance en matière de politique énergétique. La troisième partie de l'ouvrage s'intéresse aux dynamiques d'innovation, notamment des territoires en transition et des technologies émergentes. La quatrième partie est centrée sur les usages et les usagers, d'un triple point de vue, celui des conditions sociotechniques de la maîtrise de la demande, mais aussi des situations de précarité énergétique et des pratiques de certains acteurs. Les deux dernières parties proposent une focale sur l'accompagnement au changement par les nouvelles technologies « smart »
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