Christophe Varnier

Christophe Varnier
École Nationale Supérieure de Mécanique et des Microtechniques | ENSMM · Franche-Comté Electronique Mécanique Thermique et Optique - Sciences et Technologies - AS2M

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121
Publications
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Publications

Publications (121)
Article
Full-text available
In the area of well construction, the tool reliability and the field environment are two contributing factors that influence drilling job efficiency and success. Either using high specification tools in low-risk environmental or applying tools of low reliability in harsh environments is inadvisable. Thus, how to select a suitable tool fitting the e...
Conference Paper
Full-text available
The electronic boards in drilling and measurement (D&M) tools provide multiple functions, such as data acquisition, signal processing, operation control, and data storage. However, due to the harsh downhole operating conditions; i.e., high temperature, dynamic vibration, and extensive shocks, the boards are likely to suffer from complex failure mod...
Article
Because of the increasing energy consumption of data centers and their CO2 emissions, the ANR DATAZERO2 project aims to design autonomous data centers running solely on local renewable energy coupled with storage devices to overcome the intermittency issue. In order to optimize the use of renewable energy and storage devices, a MILP solver is usual...
Article
Full-text available
In light of the rapid growth of data centers around the world and their huge energy consumption, several researchers have focused on the task scheduling and resource allocation problem in order to minimize the energy consumed by the data center. Other initiatives focus on the implementation of green energy sources in order to minimize the consumpti...
Article
Full-text available
In this paper, we propose a study of the decision horizon duration for rolling stock mission assignment and maintenance planning in a prognostics and health management (PHM) context. The aim is to determine the best decision horizon duration that allows the construction of a suitable schedule that assigns railway vehicles to missions and integrates...
Article
Full-text available
In this work, we propose a two-step methodology for designing and sizing a data center solely powered by local renewable energy. The first step consists in determining the necessary IT equipment for processing a given IT workload composed of batch and service tasks. We propose an adapted binary search algorithm and prove its optimality to find the...
Article
Maintenance interventions must be properly integrated in the production scheduling in order to prevent failure risks. In this context, we investigate the permutation flowshop scheduling problem subjected to predictive maintenance based on prognostics and health management (PHM). To solve this problem, two integrated metaheuristics are proposed with...
Article
Full-text available
Mainly, the prognostics and health management (PHM) process is based on three processes: the data acquisition and health assessment process in which sensors signals are acquired and processed, the diagnostic and prognostic process in which the source of failure is detected and the remaining useful life (RUL) is predicted and finally the decision-ma...
Article
Full-text available
Prognostics and health management have become increasingly important in recent years. Many research studies focus on a crucial phase consisting of predicting the remaining useful life of equipment or a component. However, this step is often carried out without taking into account the decisions that will be taken later. This article aims to propose...
Conference Paper
Prognostics and health management (PHM) has, recently, gained a lot of attention in the rail transportation context. However, most works in this field focus on the prognostic process. However, prognostics is not the end of PHM in itself, its results have to be used to better manage the life cycle of systems. PHM decision phase is applied to plan ac...
Conference Paper
This paper addresses the problem of using prognostic information in the decision-making process of a single multi-purpose machine. The prognostics and health management method is compared to condition-based maintenance combined with a genetic algorithm to determine the joint schedule of maintenance and production. The paper presents a methodology t...
Conference Paper
Bearings usually operate under harsh conditions which result in a dynamic behavior generating non-stationary vibration signals and overwhelmed by noise. Therefore, bearing fault diagnosis and prognosis become difficult since the purpose is to extract robust features able to detect the appearance of faults, monitoring the degradation of health state...
Chapter
Being able to predict the daily activity of firefighters is of great interest to optimize human and material resources. It will allow to enable a quicker response by achieving a better geographical deployment of these resources according to the expected number of interventions. Having obtained the list of interventions for the period 2012–2017 in t...
Article
Breast cancer is a disease that threat many women's life, thus, the early and accurate detection play a key role in reducing the mortality rate. Mammography stands as the reference technique for breast cancer screening; nevertheless, many countries still lack access to mammograms due to economic, social and cultural issues. Last advances in computa...
Preprint
Full-text available
Breast cancer is one of the most threatening disease in women’s life, thus, the early and accurate diagnosis play a key role in reducing the risk of death in patient’s life. Mammography stands as the reference technique for breast cancer screening, nevertheless many countries still lack access to mammograms due to economic, social and cultural issu...
Article
As the need for cloud services has been growing steadily, the size and energy consumption of datacenters have increased significantly over the past years. Due to economic and environmental constraints, energy efficiency in datacenters and greenhouse emissions have become a major concern. Renewable energy is widely seen as a promising solution to su...
Article
Full-text available
In this paper, the problem of using prognostics information of Micro-Electro-Mechanical Systems (MEMS) for post-prognostics decision in distributed MEMS-based systems is addressed. A strategy of post-prognostics decision is proposed and then implemented in a distributed MEMS-based conveying surface. The surface is designed to convey fragile and tin...
Article
Full-text available
Uncertainty in remaining useful life (RUL) prediction is nowadays a scientific problem that occupies industrials. Many prognostic models have been developed to respond to this issue from probabilistic to non-probabilistic approaches. In this paper, we deal with a non- probabilistic model for RUL prediction. For this purpose, we propose a model, whi...
Conference Paper
Full-text available
At first, Prognostics and Health Management (PHM) was interpreted as a new trend of Condition Based Maintenance (CBM) to schedule, in a more effective way, preventive maintenance actions. Lately, PHM is being used in operational decisions like choosing the appropriate mission to execute, planning logistics actions or defining the control parameters...
Conference Paper
Full-text available
We tackle in this paper the Permutation Flowshop Scheduling Problem (PFSP) with predictive maintenance interventions. The objective is to propose an integrated model that coordinates production schedule and predictive maintenance planning so that the total time to complete the schedule after predictive maintenance insertion is minimized. Predictive...
Conference Paper
Full-text available
In this paper we present a new method which deals with the joint maintenance and assignment scheduling problem for a fleet of machines. The aim is to minimize the operation cost while satisfying a certain reliability level. For that purpose, we consider a non-homogeneous gamma process to model the degradation of the systems and estimate their relia...
Article
Full-text available
This study focuses on permutation flowshop scheduling problem (PFSP) under availability constraints with makespan and maintenance cost optimization criteria. Machines unavailabilities are due to predictive maintenance interventions scheduled based on Prognostics and Health Management (PHM) results. Hence, we deal with the post prognostic decision m...
Chapter
This chapter aims to monitor a subsystem and the health state of some of its components as well as their maintenance. In order to ensure the information's traceability, the most important part of information, which is capitalized during the whole lifecycle of the component, is assessed by means of indicators of proper functioning, a statistical cal...
Chapter
Many generations of maintenance systems have appeared, ranging from local systems to integrated computerized maintenance management systems (CMMS) initially and current systems that integrate intelligent modules that communicate with each other. This chapter focuses on existing maintenance platforms and their software architecture depending on the...
Chapter
The notion of decision within the prognostics and health management (PHM) domain deserves to be clarified. This chapter presents a typology of decisions with a state-of-the-art overview on this subject. Then, it illustrates the presented decision types in relation with temporal constraints, which are mainly due to the interval of time within which...
Chapter
By means of prognostics, it is possible to plan the maintenance interventions in accordance with the evolution of the equipment's parameters; this is the principle of predictive maintenance. This chapter presents a decision approach which aims to plan maintenance operations for a predictive maintenance policy. The decision problem can take differen...
Chapter
This chapter aims to design and develop a solution for processing and capitalizing knowledge related to industrial equipment throughout its lifecycle and for making it available for operators to easily access this equipment in an understandable way and at the required moment. It outlines some state-of-the-art intelligent products followed by a pres...
Chapter
Making increasingly complex equipment reliable and maintaining it in operational conditions whilst ensuring its durability requires an increased monitoring of critical elements and of associated maintenance strategies, notably of the predictive maintenance, which is capable of anticipating any failure. This chapter presents an illustration of post-...
Article
Full-text available
Prognostic and Health Management (PHM) benefits are strongly tied to the decision-making that follows the assimilation and interpretation of prognostics information. Hence, we deal in this study with the post prognostic decision making in order to improve system safety and avoid downtime and inopportune maintenance spending. We investigate the prob...
Conference Paper
Full-text available
Prognostics and Health Management (PHM) offers several benefits for predictive maintenance. It predicts the future behavior of a system as well as its Remaining Useful Life (RUL). This RUL is used to planned the maintenance operation to avoid the failure, the stop time and optimize the cost of the maintenance and failure. However, with the developm...
Conference Paper
Full-text available
In this paper, we propose to jointly optimize the rolling stock assignment and the maintenance scheduling in a Prognostics and Health Management (PHM) context. The aim is to determine an appropriate use of the rolling stock considering predefined train timetables and prognostics information. The problem is to associate a rolling stock unit to each...
Article
A management of multi-stacks fuel cell systems is proposed to extend systems useful life in a Prognostics and Health Management (PHM) framework. The problem consists in selecting at each time which fuel cell stacks have to run and which output power has to be chosen for each of them to satisfy a load demand as long as possible. Multi-stacks fuel ce...
Article
Full-text available
In highly competitive environment, manufacturing system availability has become a critical issue. For this reason, predictive maintenance must be properly integrated in the production scheduling in order to take into account the wear and tear of the equipment to prevent it from the failure risk. In this context, we investigate the problem of a sing...
Article
Maintenance is a strategic function in a company. It aims to ensure the proper functioning of an equipment. It no longer has the sole objective to repair a system but also to anticipate and prevent its failures. Recently new failure prediction techniques have emerged. They provide information on the real-time condition of equipment and its remainin...
Article
In a post-prognostics decision context, this paper addresses the problem of maximizing the useful life of a platform composed of several parallel machines under service constraint. Application on multi-stack fuel cell systems is considered. In order to propose a solution to the insufficient durability of fuel cells, the purpose is to define a commi...
Article
This paper presents a hybrid prognostics approach for Micro-Electro-Mechanical Systems (MEMS). The approach relies on two phases: an offline phase for the MEMS and its degradation modeling, and an online phase for its fault prognostics. The proposed approach is applied to a MEMS device consisting in an electro-thermally actuated valve. In the offli...
Conference Paper
Full-text available
In the field of production scheduling, this paper adresses the problem of maximizing the production horizon of fuel cell systems under service constraint. Convex optimization is used to define at each time the contribution of each fuel cell to the global output so as to satisfy a power demand as long as possible. An algorithm based on the Mirror-pr...
Conference Paper
Full-text available
In a post-prognostics decision context, this paper addresses the problem of maximizing the useful life of a platform composed of several parallel machines under service constraint. Application on multi-stack fuel cell systems is considered. In order to propose a solution to the insufficient durability of fuel cells, the purpose is to define a commi...
Conference Paper
Predictive maintenance of physical systems can only be achieved by monitoring their most critical elements to track their health assessment during operation. The acquired data is processed to extract relevant features, which are used to estimate the state of the system at any time and detect any loss of performance that may occur due to the critica...
Conference Paper
Maintenance planners face the challenge of ensuring maximum performance, reliability and availability of machine, at the same time reducing the maintenance costs. This is why maintenance decision-making has emerged as an important area of industrial research. The Prognostics Health Management (PHM) can offer significant benefits for maintenance; it...
Conference Paper
Maintenance planners face the challenge of ensuring maximum performance, reliability and availability of machine, at the same time reducing the maintenance costs. This is why maintenance decision-making has emerged as an important area of industrial research. The Prognostics Health Management (PHM) can offer significant benefits for maintenance; it...
Conference Paper
Recently, Prognostics and Health Management (PHM) reveals to be a key feature for industrials as it should improve manufacturing system availability and allow avoiding downtime as well as inopportune maintenance spending. In this context, we investigate the problem of scheduling several jobs on a single machine subjected to predictive maintenance b...
Chapter
We consider a surface designed to convey fragile and tiny micro-objects. It is composed of an array of decentralized blocks that contain MEMS valves. We are interested in the dynamics of the optimal path between two blocks in the surface. The criteria used for optimal paths are related to the degradation of the MEMS, namely its remaining useful lif...
Article
Many heuristics and intelligent methods have been proposed and applied in order to solve the Job Shop Scheduling Problems (JSSP). Several researches have so far been interested in solving the production planning in JSSP and few of them have focused on solving production scheduling with the presence of maintenance tasks. This paper presents a new he...
Conference Paper
This paper presents accelerated lifetime tests for an electro-thermally actuated MEMS valve in order to identify and analyze its failures. To perform the different tests, two experimental setup are specially designed. Tests consist in cycling several MEMS valves by changing at each test the operating condition: with unfiltered air, without air and...
Conference Paper
Full-text available
Many models and methodologies in order to predict the remaining useful life (RUL) of a critical component are investigated nowadays. However, estimating remaining useful life of multi-component systems is still an under explored area, especially when there are interdependencies among the components of these systems. Practically, prognostics can be...
Conference Paper
The use of fuel cells appears to be of growing interest as a potential alternative to conventional power systems. Fuel cell systems suffer however from insufficient durability and their lifetime may be improved. Prognostics results in the form of Remaining Useful Life are proposed to be used in a Prognostics and Health Management (PHM) framework to...
Conference Paper
Full-text available
The use of fuel cells appears to be of growing interest as a potential alternative to conventional power systems. Fuel cell systems suffer however from insufficient durability and their lifetime may be improved. Prognostics results in the form of Remaining Useful Life are proposed to be used in a Prognostics and Health Management (PHM) framework to...
Conference Paper
Full-text available
This paper presents a hybrid prognostic approach which is applied on electro-thermally actuated MEMS valve. The method can be applied on different categories of MEMS to assess their health state, calculate the remaining useful life (RUL) and take appropriate decisions to anticipate the failures. In this paper a detailed description of the proposed...
Technical Report
Full-text available
In the field of production scheduling, this paper addresses the problem of maximizing the production horizon of a set of independent parallel machines. Each machine is considered to be able to provide several throughputs corresponding to different operating conditions and associated to different lifetimes. Convex optimization is used to define the...
Conference Paper
Full-text available
A management of multi-stacks fuel cell systems is proposed to extend systems useful life in a Prognostics and Health Management (PHM) framework. The problem consists in selecting at each time which fuel cell stacks have to run and which output power has to be chosen for each of them to satisfy a load demand as long as possible. Multi-stacks fuel ce...
Conference Paper
Full-text available
In the field of production scheduling, this paper adresses the problem of maximizing the production horizon of a set of independent parallel machines. Each machine is considered to be able to provide several throughputs corresponding to dierent operating conditions and associated to dierent lifetimes. Convex optimization is used to dene the contrib...