Abdessamad Kobi

Abdessamad Kobi
University of Angers | UA · ISTIA _ Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS)

Professor

About

144
Publications
50,119
Reads
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2,101
Citations
Additional affiliations
September 1996 - December 2013
University of Angers

Publications

Publications (144)
Article
Full-text available
This study focused on measurement system analysis MSA through gage of Repeatability and Reproducibility R and R methods (Average and Range Xbar/R, Analysis Of Variance ANOVA, Evaluating Measurement Process EMP III) to verify the accuracy and precision of a laser diffraction particle size analyser used to monitor particles’ size in wet grinding proc...
Article
Full-text available
Optimizing maintenance and enhancing the performance of businesses are significant concerns in the modern industrial world. Predictive maintenance is emerging as an innovative approach to address these challenges, allowing companies to shift from corrective maintenance to preventive maintenance. Predictive maintenance relies on the use of advanced...
Article
Full-text available
The studied process concerns a wet grinding and cycloning unit, set up to ensure that the particle size it processes complies with the requirements in terms of pipe transport mode. Frequent shutdowns, low reliability, the risk of delivering a product with inappropriate particle size, and the lack of operational parameters’ control are all obstacles...
Article
Accelerated testing has been commonly used for the assessment of reliability of products or systems. In particular, it has been used to produce models for predicting the reliability of electronic components as a function of design and environmental parameters, or to qualify reliability. Extensive literature exists on different aspects ranging from...
Chapter
Full-text available
The rapidity of technological development and multi-criteria decision-making (MCDM) has enabled a diversity of models and multi-criteria decision support methods. Then, in Multi-criteria Decision Making problems dealing with qualitative criteria and uncertain information is suitable for the experts in order to express their judgments. It is common...
Chapter
Multi-criteria decision support (MCDA) has been one of the areas with very strong growth in operational research over the past two decades. The MCDA is often involved in ranking many concrete alternatives, from best to worst, based on several conflicting criteria. The development of MCDA methods has been driven not only by a variety of real-life is...
Chapter
Current problems are multi-objective in nature and their solution requires the consideration of conflicting objectives. Usually they have a number of solutions potentially. Thorough knowledge of the problem is required to distinguish solutions, eliminate unwanted ones, and accept the solution (s) through a decision-making process.
Chapter
FMEA is a systematic process for identifying potential design or process failure before they occur. The aim is to eliminate them or minimize the risk associated with them. The method is a procedure to analyze failure modes and classify them by severity. It is a systematic process for identifying potential failures before they occur with the intent...
Chapter
Current security systems are more and more complex, as they integrate a variety of technologies, these systems often require a long period of development. When we change the requirements, the goals are to improve the functionality, cost, or delay of the systems; but unfortunately, this change may be affected by an issue with other system security r...
Chapter
Multi-criteria decision making or multi-criteria decision analysis is a sub-discipline of operations research that explicitly considers multiple criteria in decision-making environments. Whether in our daily life or in a professional setting, there are usually many conflicting criteria that need to be assessed in decision making. Generally, multi-c...
Book
Full-text available
This book presents the multi-criteria approach to decision support, as well as the various multi-criteria tools to help avoid multi-objective optimization. The book is intended as a tool for understanding the multi-criteria tools for decision support and modeling in mathematical programming. It helps to structure models, to easily model complex con...
Article
Full-text available
The present competitive market is focusing industrial efforts on producing high-quality products with the lowest possible cost. Currently and for a long time, quality is the centred of the concerns of the industrial organizations, which provide products intended to satisfy the customer requirements. The total performance of the process and the qual...
Article
When implementing continuous improvement methodologies such as Lean and Six Sigma, one crucial aspect is to determine which quality tools to implement to achieve a performance objective. The purpose of this article is to determine the critical quality tools and their effects on companies' performance. The data was collected using a questionnaire th...
Article
Full-text available
Scedosporium species are opportunistic pathogens causing various infections, including disseminated infections in severely immunocompromised patients. Preventive measures aiming to reduce the risk of exposure to these fungi require a better knowledge on their ecology and on the sources of contamination of the patients. In this context, 99 soil samp...
Article
This book presents the multi-criteria approach to decision support, as well as the various multi-criteria tools to help avoid multi-objective optimization. The book is intended as a tool for understanding the multi-criteria tools for decision support and modeling in mathematical programming. It helps to structure models, to easily model complex con...
Article
Full-text available
In their competitiveness's research, and facing an uncertain environment, the firms search more and more to attain again objective. For that, it is necessary to minimize risks and unforeseen in their systems give complexes by the assessment risks; this one has been envisaged a long time of the technical point of view, as a first tentative to minimi...
Article
In this paper, the Conditional Gaussian Networks (CGNs), a form of Bayesian Networks (BN), are used as a statistical process monitoring approach to detect and diagnose faults. The proposed approach improves the structure of Bayesian networks and generalizes a few results regarding statistical tests and the use of an exclusion criterion. The propose...
Article
Full-text available
The authors note a correction to the article [1]. Table 5 of the original article is incomplete. Few percentage values are missing. This article presents the corrected version of Table 5.
Conference Paper
The objective of this paper is to demonstrate the utility and relevance of the use of reliability allocation methodology in the design of reliability test plans for the qualification of new medical systems. This approach makes use of all of the information collected in the preliminary product development phases. Firstly, this methodology provides a...
Article
Full-text available
Gathering public opinion by analyzing big social data has attracted wide attention due to its interactive and real time nature. For this, recent studies have relied on both social media and sentiment analysis in order to accompany big events by tracking people’s behavior. In this paper, we propose an adaptable sentiment analysis approach that analy...
Chapter
With an ever-increasing amount of both data volume and variety, traditional data processing tools became unsuitable for the big data context. This has pushed toward the creation of specific processing tools that are well aligned with emerging needs. However, it is often hard to choose the adequate solution as the wide list of available tools are co...
Article
This paper investigates the effects of measurement system variability arising from evaluations of process capabilities. In this work, relationships between true process capability indices, Cp,True and Cpm,True, and their corresponding observed indices, Cp,Obs and Cpm,Obs, are developed depending on the levels of type I and II errors. Moreover, the...
Article
Lean manufacturing and six sigma methodologies have been widely used in a large number of companies worldwide. However, many companies have found it difficult to successfully implement and sustain lean manufacturing and six sigma. It is, therefore, very important for companies to identify and understand the critical success factors for successfully...
Article
In this paper, we present a result regarding the probability distribution of wavelets coefficients. It extends the Theorem 1 that is presented in our previous work-Cohen, A. et al. Design of experiments and statistical process control using wavelets analysis. Control Engineering Practice. 2015- to include Biorthogonal wavelets. Then, a new control...
Article
Full-text available
In this paper, an AHP model was used for determining the optimal method and the most efficient methodologies of lean manufacturing and six sigma in various industries based on three criteria. These criteria are financial performance, operational performance, and innovation performance. Study results show the impact of three categories that are base...
Article
Full-text available
This study analyzes company performance by using the analytic hierarchy process (AHP) to rank the performance of participating companies. The Super Decisions software package was used to compute the rating score. The first stage of this work involved collecting empirical data via questionnaires to characterize the impact of implementing quality and...
Conference Paper
Full-text available
The purpose of this article is to determine the companies performance for industries applied lean manufacturing and six sigma. Study results indicate that companies implementing lean manufacturing and six sigma have wealthy performance across financial performance, operational performance and innovation performance. It discovers various lean six si...
Article
In this paper a control chart for monitoring the process mean, called OWave (Orthogonal Wavelets), is proposed. The statistic that is plotted in the proposed control chart is based on weighted wavelets coefficients, which are provided through the Discrete Wavelets Transform using Daubechies db2 wavelets family. The statistical behavior of the wavel...
Research
L’objectif de cette étude est de déterminer les résultats en terme de performance des entreprises ayant mis en place des pratiques de lean manufacturing et six sigma. L’étude indique que la taille de l’entreprise n’a pas d’influence sur la performance opérationnelle. Cette étude montre aussi que de telles pratiques augmentent la performance des ent...
Article
Full-text available
The aim of this study is to investigate and identify the key success factors of implementing lean manufacturing and six sigma in separate ways. The study applies a quantitative approach and statistical analysis to determine the results collected from the French industry. Findings revealed that there exist statistically significant differences in th...
Article
The purpose of this article is to present a method for Fault Detection and Diagnosis (FDD) with Bayesian network, and more particularly with Conditional Gaussian Network (CGN). A classical problem of FDD with supervised classification is when Normal Operating Conditions class is integrated, the false alarm rate is not guarantee by the classifier. T...
Thesis
La surveillance des processus est un challenge quotidien pour de nombreuses entreprises, dont l’objectif est de piloter et maîtriser leurs systèmes. Les travaux de cette thèse portent sur la surveillance des processus par les approches multi-échelle, notamment la combinaison de l’analyse par ondelettes et les approches statistiques. Nous avons étab...
Conference Paper
Full-text available
Autocorrelation and non-normality of process characteristic variables are two main difficulties that industrial engineers must face when they should implement control charting techniques. This paper presents new issues regarding the probability distribution of wavelets coefficients. Firstly, we highlight that wavelets coefficients have capacities t...
Conference Paper
Full-text available
L’objectif de cette étude est de déterminer les résultats en terme de performance des entreprises ayant mis en place des pratiques de lean manufacturing et six sigma. L’étude indique que la taille de l’entreprise n’a pas d’influence sur la performance opérationnelle. Cette étude montre aussi que de telles pratiques augmentent la performance des ent...
Conference Paper
Full-text available
In this paper, we study the performance outcomes for industries practicing lean manufacturing and six sigma. Findings indicate that company size has no influence on operational performance outcomes. Also we found that lean manufacturing and six sigma practices such as DMAIC, Kaizen team, Visual Control, SMED, 5S, etc. support to increases companies...
Article
The main interest of this paper is to illustrate a new representation of the Principal Component Analysis (PCA) for fault detection under a Conditional Gaussian Network (CGN), a special case of Bayesian networks. PCA and its associated quadratic statistics such as T2 and SPE are integrated under a sole CGN. The proposed framework projects a new obs...
Article
Full-text available
In this paper, three new connections between Wavelets analysis and Statistical Quality Control are proposed. Firstly, we show that the Discrete Wavelet Transform, using Haar wavelet, is equivalent to the Xbar-R control scheme. Results concerning the distribution of wavelets coefficients, using others wavelets families, are presented, and then a new...
Article
The purpose of this paper is to present an original method for system monitoring with Bayesian networks. Our proposal is to associate a data-driven method to another model-based under a common tool. The two methods are first modeled under a Bayesian network (conditional Gaussian network), and then combined to evaluate the system state. In the propo...
Article
In recent years, companies have emerged in an advanced competitive environment. To meet the requirements of cost reduction, customer demand, minimising delays, quality and variety improvement, companies must improve their performance to remain competitive, survive and expand. To achieve this goal, several models are used such as total quality manag...
Article
Full-text available
Today companies face great challenges due to continuous change of the environment. This dynamic change leads directly or indirectly to a flexible behavior of organizations. This organizational behavior could be characterized by: reducing the response time between demand and offer, quickly adaptation to market dynamics, fast „modernization” of the m...
Conference Paper
In this paper, we give an original representation of Principal Component Analysis (PCA) for fault detection. PCA with its corresponding quadratic test statistics are integrated under a particular case of Bayesian Networks (BNs) named Conditional Gaussian Network (CGN). The proposed network maps a new observation to an orthogonal space and gives pro...
Article
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 228, 3 (2014)
Poster
Based on fractal philosophy the aim of the research is to assess and design an innovative dynamic diamond of four differentiations of an organization (cooperation, competency, competition, and knowledge) in order to enhance organizational competitiveness. Starting from the literature a theoretical framework is developed for understanding the key co...
Article
Full-text available
This paper presents an evaluation of the performance degradation of Photovoltaic modules after few operation years in a tropical environment. To this end, the International Center for Research and Training in solar energy at Dakar University and the Lasquo-ISTIA laboratory of Angers University have put in place a research project in order to invest...
Article
Full-text available
Species of the Pseudallescheria boydii / Scedosporium apiospermum complex (PSC) are emerging fungal pathogens able to chronically colonize the airways of patients with cystic fibrosis (CF). As P. boydii was found more frequently colonizing the lungs of CF patients in France than in other European countries in a previous report, the present study wa...
Article
Full-text available
Nowadays many organizations worldwide have/are implemented/ implementing an environmental management system (EMS) according to ISO 14001, considering the context, the need to minimize negative environmental impacts, and long-term benefits. It has been observed for decades that for successful implementation of EMS are required different changes in t...
Article
Full-text available
PV modules are often considered to be the most reliable component of a photovoltaic system. The alleged reliability has led to the long warranty period for modules up to 25 years. Currently, failures resulting in module degradation are generally not considered because of the difficulty of measuring the power of a single module in a PV system and th...
Article
Full-text available
This paper proposes a method for the detection and assessment of the degradation of the photovoltaic modules electrical characteristics such as short-circuit current (Isc), open-circuit voltage (Voc) and maximum output power (Pmax). This work presents a standardization method for measurements of these characteristics in real conditions. Standardiza...
Article
Full-text available
Accelerated development of humanity in recent decades generated a double effect as a result: (a) the development of economies, creating social welfare, on the one hand, and (b) a enormous "pressure" on the environment, causing pollution, on the other hand. Therefore the organizations need efficient management systems - which can be considered - to...
Article
Full-text available
The objective of this paper is to find the effect of dust on the performance of photovoltaic modules. To this end, the International Center for Research and Training in solar energy at Dakar University and the Lasquo-ISTIA Laboratory of Angers University have put in place a research project in order to investigate the impact of Sahelian climatic co...
Poster
The new proposed approach to environmental decision making as a fractal process, is based on the necessity to correct the „major inconsistencies” observed at the multiple relationships level: environmental objectives and/ or environmental issues - environmental activities undertaken - environmental responsibility, and so on. These inconsistencies w...
Article
Full-text available
The expression "environmental decision" cannot be explained or summarized by a simple formula containing all the ideas focused on it. This paper aims to develop a conceptual framework for environmental decision (at organizations level) using fractal paradigm philosophy in its construction, with the purpose to bring order and simplicity for this typ...
Article
Full-text available
Since its introduction in 1987 the ISO 9000 series of standards has become a worldwide success, with it now considered as the minimum standard for a quality management system. The number of ISO 9001 certified companies is increasingly annually. This paper presents the results of research aimed at assessing if the motives for obtaining ISO 9001 cert...
Article
Full-text available
Dans cet article on présente une approche originale de diagnostic de fautes. Il s'agit d'une combinaison de deux méthodes de diagnostic (à base de modèle et à base de données) intégrées dans un seul et même réseau bayésien. Un exemple de simulation d'un système de chauffe-eau permet d'évaluer les performances de l'approche sous différentes hypothès...
Article
Full-text available
As various new sibling species within the Pseudallescheria boydii/Scedosporium apiospermum complex have been described recently with differences in their susceptibility to antifungals, this study was conducted in order to determine their respective frequency in cystic fibrosis. Results indicated that P. boydii largely predominated (62%), followed b...
Conference Paper
Many present-day problems are multiobjective in nature and their solution requires consideration of conflicting objectives. Usually, they have a number of potentially Pareto-optimal solutions. An extensive knowledge of the problem is required in discriminating between solutions, eliminating the unwanted ones and accepting the required solution(s) b...
Conference Paper
The human operator as the basic postulate of events appearance of catastrophes and failures; however issuing finders of diverse currents have to apply different methods to minimize risks of human errors, some have used combined methods taking counts him personals factors and engineering, others himself are supported on estimations probabilities to...
Article
Process optimization is a very important point in m odern industry. There are many classical optimization methods, which can be applied when som e mathematical conditions are verified. Real situations are not very simple so that classic al methods may not succeed in optimizing; as in cases when the optimization has several contradicto ry objectives...
Article
Process optimization is a very important point in modern industry. There are many classical optimization methods, which can be applied when some mathematical conditions are verified. Real situations are not very simple so that classical methods may not succeed in optimizing; as in cases when the optimization has several contradictory objectives (Co...
Article
In this paper, we present an original FDD method. The interest of this method is her ability to coexist residuals and measures, under a same and a single tool. Indeed, our proposal is to combine two different Bayesian networks to FDD. A model-based method is associated to a data-driven method to enhance decision making on the system operating state...
Article
The purpose of this article is to present a method for industrial process diagnosis with Bayesian network, and more particularly with conditional Gaussian network (CGN). The interest of the proposed method is to combine a discriminant analysis and a distance rejection in a CGN in order to detect new types of fault. The performances of this method a...
Article
Full-text available
This chapter is about the multivariate process monitoring (detection and diagnosis) with Bayesian networks. It allows to unify in a same tool (a Bayesian network) some monitoring dedicated methods like multivariate control charts or discriminant analysis. After the context introduction, we develop in section 2, principles of process monitoring, nam...
Conference Paper
Full-text available
The purpose of this article is to present a method for industrial process diagnosis. We are interested in fault diagnosis considered as a supervised classification task. The interest of the proposed method is to take into account new features (and so new informations) in the classifier. These new features are probabilities extracted from a Bayesian...
Conference Paper
Full-text available
The purpose of this article is to present a new method for fault detection with Bayesian network. The interest of this method is to propose a new structure of Bayesian network allowing to detect a fault in the case of a non-Gaussian signal. For that, a structure based on Gaussian mixture model is proposed. This particular structure allows to take i...
Article
The main function of food processes is to create, from original materials mainly organic products for consumption and having specific properties which depends on the overall quality of the final product. This is expressed in different fields: nutrition, sensory, health, functional properties such as convenience of use, presentation as portions. Thu...
Article
Better control of an industrial process involves the reduction of variability common and effective treatment failures. For this, more and more data are collected automatically, but the processing technique Monovar (statistical process control - MSP / SPC) becomes difficult to implement and shows its shortcomings: too frequent false alarms not detec...
Article
Full-text available
The purpose of this article is to present a method for industrial process diagnosis. We are interested in fault diagnosis considered as a supervised classification task. The interest of the proposed method is to take into account new features (and so new informations) in the classifier. These new features are probabilities extracted from a Bayesian...