Prise en compte des interactions multi-domaines lors de l’évaluation de la fiabilité prévisionnelle des systèmes mécatroniques

The mechatronic systems are hybrid, dynamic, interactive and reconfigurable. Therefore their dysfunctional modeling is very difficult. Multi-physical interactions between components have impacts on the degradation or on system failures, leading thus to more uncertainty in reliability evaluation. The work presented in this paper aims to improve the integration of multi-domain interactions in the reliability assessment of mechatronic systems. After a presentation of the state of the art of mechatronic systems reliability estimation methods, we propose to represent multi domain interactions by influential factors in the dysfunctional model. We generally use proportional hazard models; in the case of an interaction represented by a temperature stress, Arrhenius model is used

Evidential Networks for Evaluating Predictive Reliability of Mechatronics Systems under Epistemic Uncertainties

In reliability predicting field, the probabilistic approaches are based on data relating to the components which can be precisely known and validated by the return of experience REX, but in the case of complex systems with high-reliability precision such as mechatronic systems, uncertainties are inevitable and must be considered in order to predict with a degree of confidence the evaluated reliability. In this paper, firstly we present a brief review of the non-probabilistic approaches. Thereafter we present our methodology for assessing the reliability of the mechatronic system by taking into account the epistemic uncertainties (uncertainties in the reliability model and uncertainties in the reliability parameters) considered as a dynamic hybrid system and characterized by the existence of multi-domain interaction between its failed components. The key point in this study is to use an Evidential Network “EN” based on belief functions and the dynamic Bayesian network. Finally, an application is developed to illustrate the interest of the proposed methodology

Dynamic Bayesian Network for Reliability of Mechatronic System with Taking Account the Multi-Domain Interaction

This article presents a methodology for reliability prediction during the design phase of mechatronic system considered as an interactive dynamic system. The difficulty in modeling reliability of a mechatronic system is mainly due to failures related to the interaction between the different domains called Multi-domain interaction. Therefore in this paper, after a presentation of the state of the art of mechatronic systems reliability estimation methods, we propose a original approach by representing multi domain interactions by influential factors in the dysfunctional modeled by Dynamic Bayesian Networks. A case study demonstrates the interest of the proposed approach

Evaluation of the mechatronic systems reliability under parametric uncertainties

The main research intent of this paper is to evaluate the predicted reliability of mechatronic system, with take into account the epistemic uncertainties, The work reported here presents a new methodology based on integrating the petri network with the belief functions, in order to create a belief network, and to show how to propagate the parametric uncertainties in reliability models, Some notions of uncertainty related to the reliability systems are presented, subsequently a brief definition of the belief function and its application in reliability studies are detailed and how we integrate it in petri network. To take into account the interactive aspect of mechatronic systems, we introduce the uncertainties associated to this interaction, by implementing the new method proposed by using belief network. Secondly, we study the propagation of these interaction uncertainties in system reliability. Finally, in regard to applicate the methodology, an industrial example "intelligent actuator" is developed

L’évaluation de la fiabilité prévisionnelle des systèmes mécatroniques avec la prise en compte des interactions multi-domaines

The mechatronic systems are hybrid, dynamic, interactive and reconfigurable. Therefore their dysfunctional modeling is very difficult. Multi-physical interactions between components have impacts on the degradation or on system failures, leading thus to more uncertainty in reliability evaluation. The work presented in this paper aims to improve the integration of multi-domain interactions in the reliability assessment of mechatronic systems.  After a presentation of the state of the art of mechatronic systems reliability estimation methods, we propose to represent multidomain interactions by influential factors in the dysfunctional model. We generally use proportional hazard models ; in the case of an interaction represented by a temperature stress, Arrhenius model is used

‘They Called Them Communists Then … What D'You Call ‘Em Now? … Insurgents?’. Narratives of British Military Expatriates in the Context of the New Imperialism

This paper addresses the question of the extent to which the colonial past provides material for contemporary actors' understanding of difference. The research from which the paper is drawn involved interview and ethnographic work in three largely white working-class estates in an English provincial city. For this paper we focus on ten life-history interviews with older participants who had spent some time abroad in the British military. Our analysis adopts a postcolonial framework because research participants' current constructions of an amorphous 'Other' (labelled variously as black people, immigrants, foreigners, asylum-seekers or Muslims) reveal strong continuities with discourses deployed by the same individuals to narrate their past experiences of living and working as either military expatriates or spouses during British colonial rule. Theoretically, the paper engages with the work of Frantz Fanon and Edward Said. In keeping with a postcolonial approach, we work against essentialised notions of identity based on 'race' or class. Although we establish continuity between white working-class military emigration in the past and contemporary racialised discourses, we argue that the latter are not class-specific, being as much the creations of the middle-class media and political elite

Late outcome of repair of congenital coronary artery fistulas—a word of caution

ObjectivesWe reviewed our experience with repair of congenital coronary artery fistulas.MethodsFrom June 1983 to December 2009, 46 patients (median age, 59 years; range, 1-84 years) underwent surgical repair. The presenting symptoms included angina in 16 patients (35%), congestive heart failure in 11 (24%), and bacterial endocarditis in 5 (11%). Preoperatively, 9 patients (20%) had at least moderate tricuspid regurgitation. Coronary artery dominance was right in 38 patients (83%). Coronary artery aneurysms were found in 8 patients (17%). The most common pattern was right coronary artery-to-coronary sinus fistula (18 patients, 39%); 11 patients had (23%) more than 1 fistula. One patient had undergone previous coil embolization.ResultsCardiopulmonary bypass was used in 39 patients (85%), with extracardiac and intracardiac repair performed in 30 (65%) and 16 (35%), respectively. The most common associated procedures were coronary artery bypass in 13 patients (28%). Early mortality occurred in 1 patient (2%). Postoperative myocardial infarction occurred in 5 patients (11%); 4 of these patients underwent simple ligation or division of their fistulas. The mean follow-up was 6 ± 5.8 years (maximum, 22 years). Late mortality occurred in 11 patients (24%). Two patients underwent reoperation for severe tricuspid regurgitation. Survival was significantly reduced compared with the age- and gender-matched population (P = .03). Residual fistulas were detected in 3 patients (6%), with no reintervention needed.ConclusionsPerioperative myocardial infarction is an important complication of ligation of coronary artery fistulas and can contribute to reduced late survival. The tricuspid valve should be evaluated carefully at repair because of the relatively high rate of residual regurgitation in survivors

Helminth Fauna in Carnivoran Mammals from Uzbekistan

Helminths, or parasitic worms, are a group of organisms that can infect various animal species, including humans. In Uzbekistan, previous studies on the helminth fauna of mammals have mainly focused on domestic animals and some wildlife species, with little attention given to carnivoran mammals. This survey aims to conduct a comprehensive study for the first time in Uzbekistan on the helminth fauna of Carnivora. In this study, helminths were collected from 1002 carnivorans (Canidae, n = 710; Mustelidae, n = 167; and Felidae, n = 125) from five locations in Uzbekistan (Northeastern, Eastern, Central, Southern and Northwestern). A total of 71 species of helminths were identified in domestic and wild carnivores by necropsy and faecal examination, of which 36, 23, 9, and 3 species belonged to the higher taxon Nematoda, Cestoda, Trematoda and Acanthocephala respectively. The highest number of helminth species was recorded in studied Canidae (51 species), followed by Felidae (40 species) and Mustelidae (35 species). The overall infection rate of carnivorans was 79.8 %. Infection intensity ranged from a single to dozens of specimens. The statistical analysis indicated that the diversity of helminth species is significant among members of Canidae, with foxes having 42 species and dogs having 41 species (P < 0.05). Our study proves that the parasitic worm species that inhabit predatory mammals in Uzbekistan are a diverse and complex group that can cause helminthiases, which may be dangerous to livestock and humans

Candida dubliniensis candidemia in patients with chemotherapy-induced neutropenia and bone marrow transplantation.

The recently described species Candida dubliniensis has been recovered primarily from superficial oral candidiasis in HIV-infected patients. No clinically documented invasive infections were reported until now in this patient group or in other immunocompromised patients. We report three cases of candidemia due to this newly emerging Candida species in HIV-negative patients with chemotherapy-induced immunosuppression and bone marrow transplantation