Evaluating the predicted reliability of mechatronic systems: state of the art

Reliability analysis of mechatronic systems is a recent field and a dynamic branch of research. It is addressed whenever there is a need for reliable, available, and safe systems. The studies of reliability must be conducted earlier during the design phase, in order to reduce costs and the number of prototypes required in the validation of the system. The process of reliability is then deployed throughout the full cycle of development. This process is broken down into three major phases: the predictive reliability, the experimental reliability and operational reliability. The main objective of this article is a kind of portrayal of the various studies enabling a noteworthy mastery of the predictive reliability. The weak points are highlighted. Presenting an overview of all the quantitative and qualitative approaches concerned with modelling and evaluating the prediction of reliability is so important for future reliability studies and for academic research to come up with new methods and tools. The mechatronic system is a hybrid system, it is dynamic, reconfigurable, and interactive. The modeling carried out of reliability prediction must take into account these criteria. Several methodologies have been developed in this track of research. In this regard, the aforementioned methodologies will be analytically sketched in this paper.Comment: 13 page, Mechanical Engineering: An International Journal (MEIJ), Vol. 3, No. 2, May 201

Evolution of the Band Structure of β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content

The evolution of the band structure of β-In2 S3−3x O3x (BISO) thin films grown by physical vapor deposition, with composition x, is investigated using x-ray photoelectron spectroscopy. It is shown that the energy difference between the valence-band level and the Fermi level remains nearly constant as the optical band gap of the films increases. As a consequence, the difference between the conduction band level and the Fermi level increases as much as the optical band gap of the films. The calculation of the electronic affinity [ ] of the BISO thin films shows that it decreases linearly from 4.65 to 3.85 eV when x varies from 0 to 0.14. This will facilitate fabrication of efficient Cu(InGa)Se2-based solar cells having different absorber layer band gap

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

Publish, not Perish: Supporting Graduate Students as Aspiring Authors

BACKGROUND Students pursuing advanced degrees are increasingly expected to contribute to their discipline’s scholarly discourse during their tenure in graduate school. However, they are often unsure of how or where to begin the publishing process, and do not always feel comfortable asking for help from their faculty advisors or fellow students. Scholars, including librarians, have attempted to address these concerns by developing tools and services to meet the needs of future faculty. In recent years, university presses and research libraries have recognized their shared mission in furthering scholarship, with libraries themselves offering publishing education and expertise. PROJECT OVERVIEW During the 2012-2013 academic year, subject librarians and publishing professionals at the University of Michigan Library crafted a program to address students’ questions and concerns about the publishing lifecycle. This ongoing initiative includes a multi-semester workshop series developed in concert with faculty from departments throughout campus, as well as a supplementary online toolkit that takes into account the rapidly evolving nature of scholarly communication. LESSONS LEARNED Major takeaways from this program include: the value of student assessment in shaping publishing workshops; awareness of the discrepancies of registration numbers and actual attendance, highlighting the potential for enhanced promotion techniques; the importance of university press and faculty insight; and the benefits of collaboration among librarians, publishing professionals, and faculty members. NEXT STEPS Future iterations of this program will incorporate in-depth assessment of each program, a more interactive learning environment, and better scheduling and promotion of the workshop series

Bottlenecks in the Open-Access System: Voices from Around the Globe

A level playing field is key for global participation in science and scholarship, particularly with regard to how scientific publications are financed and subsequently accessed. However, there are potential pitfalls of the so-called “Gold” open-access (OA) route, in which author-paid publication charges cover the costs of production and publication. Gold OA plans in which author charges are required may not solve the access problem, but rather may shift the access barrier from reader to writer. Under such plans, everyone may be free to read papers, but it may still be prohibitively expensive to publish them. In a scholarly community that is increasingly global, spread over more and more regions and countries of the world, these publication access barriers may be quite significant. In the present paper, a global suite of colleagues in academe joins this debate. The group of colleagues, a network of researchers active in scholarly publishing, spans four continents and multiple disciplines in the natural sciences, humanities, and social sciences, as well as diverse political and economic situations. We believe that this global sampling of researchers can provide the nuance and perspective necessary to grasp this complex problem. The group was assembled without an attempt to achieve global coverage through random sampling.This contribution differs from other approaches to the open-access problem in several fundamental ways. (A) It is scholar-driven, and thus can represent the ‘other side of the coin’ of scholarly communication. (B) It focuses on narrative report, where scholars were free to orient their responses as they saw fit, rather than being confined to binary or scalar choices. Finally, and perhaps most importantly, (C) it distinguishes among institutions and countries and situations, highlighting inequalities of access among wealthy and economically-challenged nations, and also within countries depending on the size and location of particular institutions

Cu(In,Ga)Se2 absorber thinning and the homo-interface model: Influence of Mo back contact and 3-stage process on device characteristics

Thinning the absorber layer is one of the possibilities envisaged to further decrease the production costs of Cu(In,Ga)Se2 (CIGSe) thin films solar cell technology. In the present study, the electronic transport in submicron CIGSe-based devices has been investigated and compared to that of standard devices. It is observed that when the absorber is around 0.5 μm-thick, tunnelling enhanced interface recombination dominates, which harms cells energy conversion efficiency. It is also shown that by varying either the properties of the Mo back contact or the characteristics of 3-stage growth processing, one can shift the dominating recombination mechanism from interface to space charge region and thereby improve the cells efficiency. Discussions on these experimental facts led to the conclusions that 3-stage process implies the formation of a CIGSe/CIGSe homo-interface, whose location as well as properties rule the device operation; its influence is enhanced in submicron CIGSe based solar cells