11 research outputs found

    The development of CMMS incorporating condition monitoring tools in the advances of Industry 4

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    Computerized maintenance management software (CMMS) considered effective supporting tools to enhance the organisation and scheduling practices of maintenance tasks on manufacturing assets. Condition monitoring applications in the advances of Industry 4.0 applications enhances machines condition insight by utilising different sensing nodes to improve the optimisation of the scheduled maintenance tasks and support predictive maintenance applications. To overcome the disconnection between condition monitoring technology and CMMS software, the research presents a new generation of CMMS by integrating condition monitoring technologies with maintenance management functionalities under a single cloud-based platform. As an example, energy data from five-axis machine tools are included to show it is predictable and stable to be reliable for failures prediction applications

    Development of maintenance framework for modern manufacturing systems

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    Modern manufacturing organizations are designing, building and operating large, complex and often ‘one of a kind’ assets, which incorporate the integration of various systems under modern control systems. Due to such complexity, machines failures became more difficult to interpret and rectify and the existing maintenance strategies became obsolete without development and enhancement. As a result, the need for more advanced strategies to ensure effective maintenance applications that ensures high operation efficiency arise. The current research aims to investigate the existing maintenance strategies, the levels of machines complexity and automation within manufacturing companies from different sectors and sizes including, oil and gas, food and beverages, automotive, aerospace, and Original Equipment Manufacturer. Results analysis supports in the development of a modern maintenance framework that overcome the highlighted results and suits modern manufacturing assets using systematic approaches and utilisation of pillars from Total productive maintenance (TPM, Reliability Centred Maintenance (RCM) and Industry 4.0

    Fault Prognostics Using Logical Analysis of Data and Non-Parametric Reliability Estimation Methods

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    RÉSUMÉ : Estimer la durĂ©e de vie utile restante (RUL) d’un systĂšme qui fonctionne suivant diffĂ©rentes conditions de fonctionnement reprĂ©sente un grand dĂ©fi pour les chercheurs en maintenance conditionnelle (CBM). En effet, il est difficile de comprendre la relation entre les variables qui reprĂ©sentent ces conditions de fonctionnement et la RUL dans beaucoup de cas en pratique Ă  cause du degrĂ© Ă©levĂ© de corrĂ©lation entre ces variables et leur dĂ©pendance dans le temps. Il est Ă©galement difficile, voire impossible, pour des experts d’acquĂ©rir et accumuler un savoir Ă  propos de systĂšmes complexes, oĂč l'Ă©chec de l'ensemble du systĂšme est vu comme le rĂ©sultat de l'interaction et de la concurrence entre plusieurs modes de dĂ©faillance. Cette thĂšse prĂ©sente des mĂ©thodologies pour le pronostic en CBM basĂ© sur l'apprentissage automatique, et une approche de dĂ©couverte de connaissances appelĂ©e Logical Analysis of Data (LAD). Les mĂ©thodologies proposĂ©es se composent de plusieurs implĂ©mentations de la LAD combinĂ©es avec des mĂ©thodes non paramĂ©triques d'estimation de fiabilitĂ©. L'objectif de ces mĂ©thodologies est de prĂ©dire la RUL du systĂšme surveillĂ© tout en tenant compte de l'analyse des modes de dĂ©faillance uniques ou multiples. Deux d’entre elles considĂšrent un mode de dĂ©faillance unique et une autre considĂšre de multiples modes de dĂ©faillance. Les deux mĂ©thodologies pour le pronostic avec mode unique diffĂšrent dans la maniĂšre de manipuler les donnĂ©es. Les mĂ©thodologies de pronostique dans cette recherche doctorale ont Ă©tĂ© testĂ©es et validĂ©es sur la base d'un ensemble de tests bien connus. Dans ces tests, les mĂ©thodologies ont Ă©tĂ© comparĂ©es Ă  des techniques de pronostic connues; le modĂšle Ă  risques proportionnels de Cox (PHM), les rĂ©seaux de neurones artificiels (ANNs) et les machines Ă  vecteurs de support (SVMs). Deux ensembles de donnĂ©es ont Ă©tĂ© utilisĂ©s pour illustrer la performance des trois mĂ©thodologies: l'ensemble de donnĂ©es du turborĂ©acteur Ă  double flux (turbofan) qui est disponible au sein de la base de donnĂ©es pour le dĂ©veloppement d'algorithmes de pronostic de la NASA, et un autre ensemble de donnĂ©es obtenu d’une vĂ©ritable application dans l'industrie. Les rĂ©sultats de ces comparaisons indiquent que chacune des mĂ©thodologies proposĂ©es permet de prĂ©dire avec prĂ©cision la RUL du systĂšme considĂ©rĂ©. Cette recherche doctorale conclut que l’approche utilisant la LAD possĂšde d’importants mĂ©rites et avantages qui pourraient ĂȘtre bĂ©nĂ©fiques au domaine du pronostic en CBM. Elle est capable de gĂ©rer les donnĂ©es en CBM qui sont corrĂ©lĂ©es et variantes dans le temps. Son autre avantage et qu’elle gĂ©nĂšre un savoir interprĂ©table qui est bĂ©nĂ©fique au personnel de maintenance.----------ABSTRACT : Estimating the remaining useful life (RUL) for a system working under different operating conditions represents a big challenge to the researchers in the condition-based maintenance (CBM) domain. The reason is that the relationship between the covariates that represent those operating conditions and the RUL is not fully understood in many practical cases, due to the high degree of correlation between such covariates, and their dependence on time. It is also difficult or even impossible for the experts to acquire and accumulate the knowledge from a complex system, where the failure of the system is regarded as the result of interaction and competition between several failure modes. This thesis presents systematic CBM prognostic methodologies based on a pattern-based machine learning and knowledge discovery approach called Logical Analysis of Data (LAD). The proposed methodologies comprise different implementations of the LAD approach combined with non-parametric reliability estimation methods. The objective of these methodologies is to predict the RUL of the monitored system while considering the analysis of single or multiple failure modes. Three different methodologies are presented; two deal with single failure mode and one deals with multiple failure modes. The two methodologies for single mode prognostics differ in the way of representing the data. The prognostic methodologies in this doctoral research have been tested and validated based on a set of widely known tests. In these tests, the methodologies were compared to well-known prognostic techniques; the proportional hazards model (PHM), artificial neural networks (ANNs) and support vector machines (SVMs). Two datasets were used to illustrate the performance of the three methodologies: the turbofan engine dataset that is available at NASA prognostic data repository, and another dataset collected from a real application in the industry. The results of these comparisons indicate that each of the proposed methodologies provides an accurate prediction for the RUL of the monitored system. This doctoral research concludes that the LAD approach has attractive merits and advantages that add benefits to the field of prognostics. It is capable of dealing with the CBM data that are correlated and time-varying. Another advantage is its generation of an interpretable knowledge that is beneficial to the maintenance personnel

    Developed Algorithms for Maximum Pattern Generation in Logical Analysis of Data

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    RÉSUMÉ : Les donnĂ©es sont au coeur des industries et des organisations. Beaucoup d’entreprises possĂšdent de grandes quantitĂ©s de donnĂ©es mais Ă©chouent Ă  en tirer un bĂ©nĂ©fice consĂ©quent, bien souvent parce que ces donnĂ©es ne sont pas utilisĂ©es de façon productive. Il est indispensable de prendre des dĂ©cisions importantes au bon moment, en utilisant des outils adaptĂ©s permettant d’extraire de l’information pratique et fiable de grandes quantitĂ©s de donnĂ©es. Avec l’augmentation de la quantitĂ© et de la variĂ©tĂ© des donnĂ©es, le recours aux outils traditionnels facultatifs a Ă©tĂ© abandonnĂ© alors que l’importance de fournir des mĂ©thodes efficaces et prometteuses pour l’analyse de donnĂ©es se fait grandissante. La classification de donnĂ©es est l’un des moyens de rĂ©pondre Ă  ce besoin d’analyse de donnĂ©es. L’analyse Logique de DonnĂ©es (LAD : Logical Analysis of Data) est une nouvelle mĂ©thodologie d’analyse de donnĂ©es. Cette mĂ©thodologie qui combine l’optimisation, l’analyse combinatoire et la logique boolĂ©enne, est applicable pour le problĂšme de classification des donnĂ©es. Son but est de trouver des motifs logiques cachĂ©s qui sĂ©parent les observations d’une certaine classe de toutes les autres observations. Ces motifs sont les blocs de base de l’Analyse Logique de DonnĂ©es dont l’objectif principal est de choisir un ensemble de motifs capable de classifier correctement des observations. La prĂ©cision d’un modĂšle mesure Ă  quel point cet objectif est atteint par le modĂšle. Dans ce projet de recherche, on s’intĂ©resse Ă  un type particulier de motifs appelĂ© α-motif « α-pattern ». Ce type de motif permet de construire des modĂšles de classification LAD de trĂšs grande prĂ©cision. En dĂ©pit du grand nombre de mĂ©thodologies existantes pour gĂ©nĂ©rer des α-motifs maximaux, il n’existe pas encore de mĂ©ta-heuristique adressant ce problĂšme. Le but de ce projet de recherche est donc de dĂ©velopper une mĂ©ta-heuristique pour rĂ©soudre le problĂšme des α-motifs maximaux. Cette mĂ©ta-heuristique devra ĂȘtre efficace en termes de temps de rĂ©solution et aussi en termes de prĂ©cision des motifs gĂ©nĂ©rĂ©s. Afin de satisfaire les deux exigences citĂ©es plus haut, notre choix s’est portĂ© sur le recuit simulĂ©. Nous avons utilisĂ© le recuit simulĂ© pour gĂ©nĂ©rer des α-motifs maximaux avec une approche diffĂ©rente de celle pratiquĂ©e dans le modĂšle BLA. La performance de l’algorithme dĂ©veloppĂ© est Ă©valuĂ©e dans la suite. Les rĂ©sultats du test statistique de Friedman montrent que notre algorithme possĂšde les meilleures performances en termes de temps de rĂ©solution. De plus, pour ce qui est de la prĂ©cision, celle fournie par notre algorithme est comparable Ă  celles des autres mĂ©thodes. Notre prĂ©cision possĂšde par ailleurs de forts niveaux de confiance statistiques.----------ABSTRACT : Data is the heart of any industry or organization. Most of the companies are gifted with a large amount of data but they often fail to gain valuable insight from it, which is often because they cannot use their data productively. It is crucial to make essential and on-time decisions by using adapted tools to find applicable and accurate information from large amount of data. By increasing the amount and variety of data, the use of facultative traditional methods, were abolished and the importance of providing efficient and fruitful methods to analyze the data is growing. Data classification is one of the ways to fulfill this need of data analysis. Logical Analysis of Data is a methodology to analyze the data. This methodology, the combination of optimization, combinatorics and Boolean logic, is applicable for classification problems. Its aim is to discover hidden logical patterns that differentiate observations pertaining to one class from all of the other observations. Patterns are the key building blocks in LAD. Choosing a set of patterns that is capable of classifying observations correctly is the essential goal of LAD. Accuracy represents how successfully this goal is met. In this research study, one specific kind of pattern, called maximum α-pattern, is considered. This particular pattern helps building highly accurate LAD classification models. In spite of various presented methodologies to generate maximum α-pattern there is not yet any developed meta-heuristic algorithm. This research study is presented here with the objective of developing a meta-heuristic algorithm generating maximum α-patterns that are effective both in terms of computational time and accuracy. This study proposes a computationally efficient and accurate meta-heuristic algorithm based on the Simulated Annealing approach. The aim of the developed algorithm is to generate maximum α-patterns in a way that differs from the best linear approximation model proposed in the literature. Later, the performance of the new algorithm is evaluated. The results of the statistical Friedman test shows that the algorithm developed here has the best performance in terms of computational time. Moreover, its performance in terms of accuracy is competitive to other methods with, statistically speaking, high levels of confidence

    Analyse logique de données pour estimer le taux de présence des passagers en transport aérien.

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    RÉSUMÉ Chaque annĂ©e, dans l’industrie du transport aĂ©rien, des pertes de revenus additionnels estimĂ©es Ă  des millions de dollars sont causĂ©es par des passagers absents. En effet, ces siĂšges qui ont Ă©tĂ© vendus mais qui seront inoccupĂ©s peuvent potentiellement ĂȘtre revendus Ă  d’autres passagers si on est capable d’en estimer le nombre correctement. Cela gĂ©nĂšre des profits supplĂ©mentaires pour les compagnies aĂ©riennes, Ă  condition de ne pas sur-utiliser cette façon de faire, car un passager Ă  qui l’on refuse l’embarquement dĂ» Ă  un manque de place sur l’avion devient coĂ»teux, puisqu’il faut le dĂ©dommager. Le projet de maĂźtrise consiste en l’élaboration d’un modĂšle permettant de mieux prĂ©voir le nombre de siĂšges supplĂ©mentaires par rapport Ă  la capacitĂ© initiale de la cabine que l’on peut se permettre de vendre, phĂ©nomĂšne appelĂ© la survente. L’approche retenue est le « Logical Analysis of Data », auquel nous ferons rĂ©fĂ©rence par la mĂ©thode LAD. Plus spĂ©cifiquement, le modĂšle classifie les passagers en trois groupes: prĂ©sents, absents et incertains, chaque groupe possĂ©dant son propre taux de prĂ©sence. La somme pondĂ©rĂ©e de ces trois groupes et de leurs taux respectifs constitue le nombre de personnes prĂ©sentes prĂ©vues par la mĂ©thode LAD. Cette mĂ©thode a Ă©tĂ© retenue Ă  cause de son originalitĂ© et de ses succĂšs connus Ă  ce jour. Elle se distingue des autres formes de data mining plus conventionnelles par le fait qu’elle fait preuve d’une certaine forme d’intelligence artificielle; Ă  partir des caractĂ©ristiques des passagers, elle Ă©tablit des combinaisons de conditions (appelĂ©es patrons) pour lesquels les passagers ciblĂ©s ont une plus forte tendance Ă  ĂȘtre prĂ©sents (ou absents). Les caractĂ©ristiques sont par exemple la classe de rĂ©servation, le jour de la semaine du dĂ©part, l’heure, l’origine de l’itinĂ©raire
----------ABSTRACT In the airline industry, revenue losses are estimated to reach millions of dollars yearly due to passengers that don’t show up for their flights, this is referred to as «no-shows». A frequent practice in the airline industry is to overbook flights to make up for these losses. Some significant revenues can be generated by this practice if the forecasts are accurate. If the no-show forecast is too low, potential revenue loss will remain. On the other hand, if the forecast suggests too many no-shows, some passengers may be denied boarding. This has a direct negative impact on customer satisfaction, and it is difficult to determine the exact cost of customer’s frustration. The objective of this master’s project is to build a model that would improve the accuracy of predictions for show and no-show passengers, and consequently adjust the overbooking levels. The chosen method is known as the «Logical Analysis of Data», also referred to as LAD. Specifically, this method classifies all passengers into three groups: positive (showing up), negative (no-shows) and unclassified. Each of these three groups has its own show rate. The weighted sum of these groups and their show rate results in the total show rate for the evaluated group of passengers. This approach was chosen not only for its originality, but also for its success in various sectors. It differs from other conventional data mining methods by its ability to detect combinatory information about the passengers. The input consists of a number of observations (passengers), each described by a vector of attributes derived from characteristics such as booking class, day of the week, departure time, itinerary origin, 
 The LAD method detects sets of conditions on attributes for which the group of passengers respecting these conditions have a significantly higher or lower show rate

    Multi-Criteria Inventory Classification and Root Cause Analysis Based on Logical Analysis of Data

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    RÉSUMÉ : La gestion des stocks de piĂšces de rechange donne un avantage concurrentiel vital dans de nombreuses industries, en passant par les entreprises Ă  forte intensitĂ© capitalistique aux entreprises de service. En raison de la quantitĂ© Ă©levĂ©e d'unitĂ©s de gestion des stocks (UGS) distinctes, il est presque impossible de contrĂŽler les stocks sur une base unitaire ou de porter la mĂȘme attention Ă  toutes les piĂšces. La gestion des stocks de piĂšces de rechange implique plusieurs intervenants soit les fabricants d'Ă©quipement d'origine (FEO), les distributeurs et les clients finaux, ce qui rend la gestion encore plus complexe. Des piĂšces de rechange critiques mal classĂ©es et les ruptures de stocks de piĂšces critiques ont des consĂ©quences graves. Par consĂ©quent il est essentiel de classifier les stocks de piĂšces de rechange dans des classes appropriĂ©es et d'employer des stratĂ©gies de contrĂŽle conformes aux classes respectives. Une classification ABC et certaines techniques de contrĂŽle des stocks sont souvent appliquĂ©es pour faciliter la gestion UGS. La gestion des stocks de piĂšces de rechange a pour but de fournir des piĂšces de rechange au moment opportun. La classification des piĂšces de rechange dans des classes de prioritĂ© ou de criticitĂ© est le fondement mĂȘme de la gestion Ă  grande Ă©chelle d’un assortiment trĂšs variĂ© de piĂšces. L'objectif de la classification est de classer systĂ©matiquement les piĂšces de rechange en diffĂ©rentes classes et ce en fonction de la similitude des piĂšces tout en considĂ©rant leurs caractĂ©ristiques exposĂ©es sous forme d'attributs. L'analyse ABC traditionnelle basĂ©e sur le principe de Pareto est l'une des techniques les plus couramment utilisĂ©es pour la classification. Elle se concentre exclusivement sur la valeur annuelle en dollar et nĂ©glige d'autres facteurs importants tels que la fiabilitĂ©, les dĂ©lais et la criticitĂ©. Par consĂ©quent l’approche multicritĂšres de classification de l'inventaire (MCIC) est nĂ©cessaire afin de rĂ©pondre Ă  ces exigences. Nous proposons une technique d'apprentissage machine automatique et l'analyse logique des donnĂ©es (LAD) pour la classification des stocks de piĂšces de rechange. Le but de cette Ă©tude est d'Ă©tendre la mĂ©thode classique de classification ABC en utilisant une approche MCIC. Profitant de la supĂ©rioritĂ© du LAD dans les modĂšles de transparence et de fiabilitĂ©, nous utilisons deux exemples numĂ©riques pour Ă©valuer l'utilisation potentielle du LAD afin de dĂ©tecter des contradictions dans la classification de l'inventaire et de la capacitĂ© sur MCIC. Les deux expĂ©riences numĂ©riques ont dĂ©montrĂ© que LAD est non seulement capable de classer les stocks mais aussi de dĂ©tecter et de corriger les observations contradictoires en combinant l’analyse des causes (RCA). La prĂ©cision du test a Ă©tĂ© potentiellement amĂ©liorĂ©, non seulement par l’utilisation du LAD, mais aussi par d'autres techniques de classification d'apprentissage machine automatique tels que : les rĂ©seaux de neurones (ANN), les machines Ă  vecteurs de support (SVM), des k-plus proches voisins (KNN) et NaĂŻve Bayes (NB). Enfin, nous procĂ©dons Ă  une analyse statistique afin de confirmer l'amĂ©lioration significative de la prĂ©cision du test pour les nouveaux jeux de donnĂ©es (corrections par LAD) en comparaison aux donnĂ©es d'origine. Ce qui s’avĂšre vrai pour les cinq techniques de classification. Les rĂ©sultats de l’analyse statistique montrent qu'il n'y a pas eu de diffĂ©rence significative dans la prĂ©cision du test quant aux cinq techniques de classification utilisĂ©es, en comparant les donnĂ©es d’origine avec les nouveaux jeux de donnĂ©es des deux inventaires.----------ABSTRACT : Spare parts inventory management plays a vital role in maintaining competitive advantages in many industries, from capital intensive companies to service networks. Due to the massive quantity of distinct Stock Keeping Units (SKUs), it is almost impossible to control inventory by individual item or pay the same attention to all items. Spare parts inventory management involves all parties, from Original Equipment Manufacturer (OEM), to distributors and end customers, which makes this management even more challenging. Wrongly classified critical spare parts and the unavailability of those critical items could have severe consequences. Therefore, it is crucial to classify inventory items into classes and employ appropriate control policies conforming to the respective classes. An ABC classification and certain inventory control techniques are often applied to facilitate SKU management. Spare parts inventory management intends to provide the right spare parts at the right time. The classification of spare parts into priority or critical classes is the foundation for managing a large-scale and highly diverse assortment of parts. The purpose of classification is to consistently classify spare parts into different classes based on the similarity of items with respect to their characteristics, which are exhibited as attributes. The traditional ABC analysis, based on Pareto's Principle, is one of the most widely used techniques for classification, which concentrates exclusively on annual dollar usage and overlooks other important factors such as reliability, lead time, and criticality. Therefore, multi-criteria inventory classification (MCIC) methods are required to meet these demands. We propose a pattern-based machine learning technique, the Logical Analysis of Data (LAD), for spare parts inventory classification. The purpose of this study is to expand the classical ABC classification method by using a MCIC approach. Benefiting from the superiority of LAD in pattern transparency and robustness, we use two numerical examples to investigate LAD’s potential usage for detecting inconsistencies in inventory classification and the capability on MCIC. The two numerical experiments have demonstrated that LAD is not only capable of classifying inventory, but also for detecting and correcting inconsistent observations by combining it with the Root Cause Analysis (RCA) procedure. Test accuracy improves potentially not only with the LAD technique, but also with other major machine learning classification techniques, namely artificial neural network (ANN), support vector machines (SVM), k-nearest neighbours (KNN) and NaĂŻve Bayes (NB). Finally, we conduct a statistical analysis to confirm the significant improvement in test accuracy for new datasets (corrections by LAD) compared to original datasets. This is true for all five classification techniques. The results of statistical tests demonstrate that there is no significant difference in test accuracy in five machine learning techniques, either in the original or the new datasets of both inventories

    Estimation quantitative du risque liĂ© aux machines en exploitant des rapports d’enquĂȘte d’accident et l’analyse logique de donnĂ©es

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    RÉSUMÉ : Les prĂ©ventionnistes en sĂ©curitĂ© des machines utilisent diffĂ©rents outils, dont des rapports d’enquĂȘtes d’accidents, pour les aider dans l’identification des risques en milieu de travail. L’information est alors extraite ponctuellement, en lisant un rapport Ă  la fois. Par la suite, les rapports consultĂ©s risquent de sombrer dans l’oubli. En matiĂšre de gestion du risque, l’identification du risque est succĂ©dĂ©e par l’estimation du risque. Les prĂ©ventionnistes en sĂ©curitĂ© des machines utilisent gĂ©nĂ©ralement des outils qualitatifs pour estimer le risque. Cet aspect qualitatif crĂ©e de la subjectivitĂ© dans les prises de dĂ©cision quant aux moyens de rĂ©duction du risque. De plus, la nature statique de ces outils contraint son utilisateur Ă  des paramĂštres du risque prĂ©dĂ©terminĂ©s. Si d’autres paramĂštres sont requis pour mieux dĂ©finir le risque qui a Ă©voluĂ©, ces outils seront incapables de les intĂ©grer. Cela peut conduire Ă  des dĂ©cisions inadaptĂ©es en matiĂšre de rĂ©duction du risque. Pour pallier ces inconvĂ©nients, cette thĂšse vise Ă  proposer une dĂ©marche d’identification et d’estimation du risque qui facilite le suivi des risques liĂ©s aux machines, ainsi qu’à leur environnement physique et organisationnel en milieu de travail. La dĂ©marche utilise le retour d’expĂ©rience (REX) dynamique pour exploiter efficacement et durablement les rapports d’enquĂȘte d’accident. Le REX dynamique est Ă  la fois un processus de remontĂ©e d’information et d’infĂ©rence de connaissances. La connaissance essentielle est extraite Ă  partir de l’information contenue dans les rapports, aprĂšs que l’information ait Ă©tĂ© formalisĂ©e dans une base de donnĂ©es. Cette connaissance peut ĂȘtre actualisĂ©e au fur et Ă  mesure de la mise Ă  jour de la base de donnĂ©es par la remontĂ©e d’information. La connaissance est infĂ©rĂ©e sous la forme de rĂšgles pertinentes gĂ©nĂ©rĂ©es par un algorithme de fouille de donnĂ©es. Une rĂšgle est une combinaison de conditions dĂ©crivant des accidents appartenant Ă  un mĂȘme ensemble, appelĂ© « classe ». Chaque condition se compose d’un indicateur auquel une valeur ou une plage de valeurs est affectĂ©e. Un indicateur est un facteur de risque ou une cause potentielle d’accident. Ainsi, avec le REX dynamique utilisant une base de donnĂ©es pouvant ĂȘtre mise Ă  jour rĂ©guliĂšrement, les connaissances issues des rapports seront continuellement mises Ă  profit et Ă©volueront avec le contexte. Un algorithme d’apprentissage automatique nommĂ© « Analyse logique de donnĂ©es (ALD) » (Logical Analysis of Data : LAD) est intĂ©grĂ© au REX dynamique pour assurer que la dĂ©marche proposĂ©e fonctionne mĂȘme pour un Ă©chantillon restreint de donnĂ©es. En effet, cette thĂšse a dĂ©montrĂ© que, pour un petit Ă©chantillon de 23 accidents liĂ©s Ă  des convoyeurs Ă  courroie, l’ALD est capable de gĂ©nĂ©rer des rĂšgles avec une prĂ©cision de classification adĂ©quate : entre 72% et 74%. Le choix des convoyeurs Ă  courroie s’appuie sur deux constats. PremiĂšrement, de tous les types de convoyeurs, ceux Ă  courroie ont provoquĂ© le plus d’accidents (16,8%) entre 1990 et 2011, d’aprĂšs 137 rapports d’accidents de la Commission des normes, de l’équitĂ©, de la santĂ© et de la sĂ©curitĂ© du travail (CNESST) liĂ©s Ă  des convoyeurs. DeuxiĂšmement, ce type de convoyeurs reprĂ©sente la plus grande proportion (8,5%) des accidents graves et mortels, toutes machines confondues, entre 1999 et 2007, d’aprĂšs une base de donnĂ©es de l’Institut de recherche Robert-SauvĂ© en santĂ© et en sĂ©curitĂ© du travail (IRSST). Les 23 rapports d’accidents traitĂ©s dans cette thĂšse, proviennent du Centre de documentation de la CNESST. Une analyse de l’information de chaque rapport a permis de tirer les Ă©lĂ©ments dĂ©crivant le contexte accidentel. Ce traitement d’information a donnĂ© naissance Ă  une base de donnĂ©es Ă  partir de laquelle l’ALD a gĂ©nĂ©rĂ© deux sĂ©ries de rĂšgles. D’abord, l’une pour une version de la base de donnĂ©es divisant les 23 accidents en une classe d’accidents en maintenance et une classe d’accidents en production. Ensuite, l’autre pour une version de la base de donnĂ©es partageant les 23 accidents en deux classes: « Non mortel » et « Mortel ». Certaines des rĂšgles gĂ©nĂ©rĂ©es ont montrĂ© qu’un accident peut survenir en raison de conditions dangereuses (ex., un environnement de travail encombrĂ©), mais aussi en prĂ©sence de conditions d’apparence sĂ©curitaire (ex., l’existence d’un programme de prĂ©vention). Dans ce dernier cas, il faut investiguer pour comprendre les dessous d’une condition qui semble sĂ©curitaire. Par exemple, pour 60% des accidents en maintenance survenus en dĂ©pit de l’existence d’un programme de prĂ©vention, l’omission de sa mise Ă  jour pourrait expliquer l’accident. D’autres rĂšgles ont montrĂ© que les accidents analysĂ©s s’expliquent principalement par des facteurs de risque ou causes rattachĂ©es Ă  l’équipement, l’organisation, l’individu, ou le moment. Des paramĂštres quantitatifs associĂ©s aux rĂšgles, tels que leurs couvertures et la frĂ©quence de leurs indicateurs, ont permis d’entamer la hiĂ©rarchisation des rĂšgles et des facteurs de risques (la couverture est le nombre d’accidents que dĂ©crit la rĂšgle). Une mĂ©thode dĂ©veloppĂ©e pour estimer la probabilitĂ© du dommage associĂ© Ă  chaque rĂšgle a permis de complĂ©ter la hiĂ©rarchisation des rĂšgles de couvertures identiques. Cette hiĂ©rarchie, Ă©tablie sur une base quantitative, aide les prĂ©ventionnistes Ă  dĂ©terminer de maniĂšre objective les facteurs de risque ou causes possibles d’accident Ă  prioriser. La mĂ©thode exploite les fonctions de masse des indicateurs composant la rĂšgle. L’étude a montrĂ© que la probabilitĂ© des rĂšgles caractĂ©risant les accidents mortels analysĂ©s est supĂ©rieure Ă  celle des rĂšgles dĂ©crivant les accidents non mortels Ă©tudiĂ©s. Constat surprenant puisque, dans la rĂ©alitĂ©, les accidents non mortels (graves et non graves) sont plus frĂ©quents que ceux mortels. Ce constat s’explique par le fait que les accidents analysĂ©s proviennent du Centre de documentation de la CNESST qui publie des rapports d’enquĂȘte uniquement d’accidents graves ou mortels. Puisque dans la thĂšse, les accidents avec la plus grande gravitĂ© du dommage (mortels) sont aussi les plus probables, il est suggĂ©rĂ© que les prĂ©ventionnistes des entreprises concernĂ©es par les accidents analysĂ©s entament le processus de rĂ©duction du risque en s’attaquant d’abord Ă  la prĂ©vention de dommages mortels. La probabilitĂ© du dommage calculĂ©e permettra d’avoir un rĂ©fĂ©rentiel de comparaison permettant de suivre l’évolution du risque. Par exemple, Ă  la suite de la mise en Ɠuvre d’un moyen de rĂ©duction du risque, il sera possible d’en Ă©valuer l’impact sur la probabilitĂ© du dommage initialement calculĂ©e. La dĂ©marche proposĂ©e est transposable Ă  des Ă©quipements industriels autres que les convoyeurs Ă  courroie. Elle peut ĂȘtre utilisĂ©e pour l’estimation de la probabilitĂ© d’occurrence d’un Ă©vĂ©nement dangereux de nature diverse. Cette probabilitĂ© calculĂ©e pourra ĂȘtre intĂ©grĂ©e Ă  des outils qualitatifs, dans le but de prĂ©ciser leurs niveaux de probabilitĂ© d’occurrence d’un Ă©vĂ©nement dangereux. Cette intĂ©gration rendra le processus d’estimation du risque plus objectif. Le succĂšs de la dĂ©marche proposĂ©e repose sur la bonne volontĂ© des intervenants Ă  faire remonter l’information concernant les risques liĂ©s aux machines. Si aucun intervenant ne rĂ©vĂšle d’information relative Ă  un nouvel Ă©tat d’un moyen de rĂ©duction du risque ou Ă  un nouvel accident ou incident, l’information ne sera jamais enregistrĂ©e dans la base de donnĂ©es. Alors, les rĂšgles dĂ©crivant le risque ne seront jamais actualisĂ©es. ConsĂ©quemment, il en sera autant pour les facteurs de risques et les causes potentielles d’accidents, ainsi que les probabilitĂ©s associĂ©es. Dans pareil contexte, des dĂ©cisions dĂ©passĂ©es risquent d’ĂȘtre prises pour rĂ©duire le risque. Une culture de sĂ©curitĂ© et une confiance mutuelle dans l’entreprise sont primordiales afin d’encourager la remontĂ©e d’information pour brosser un portrait plus juste du risque et amĂ©liorer l’efficacitĂ© des moyens de rĂ©duction du risque.----------ABSTRACT : In machinery safety, safety practitioners use different sources as accident investigation reports to help them identify the risks in the workplace. In that case, they retrieve the knowledge from those reports one at a time, then may forget about them later. Risk identification is followed by risk estimation in risk management. Safety practitioners in machinery safety generally use qualitative tools to estimate the risk. The qualitative aspect entails subjective decision-making regarding risk reduction measures. Moreover, the static nature of those tools forces its users to work with predetermined risk parameters. If new parameters are required to better describe the changing risk, those tools will be unable to consider them, which will lead to outdated decisions in risk reduction. To overcome these issues, this thesis aims at suggesting a risk identification and risk estimation method that facilitates tracking of machinery-related risk in the workplace as well as their physical and organizational environment. That method exploits dynamic experience feedback (ExF) to make the most out of the reports in an efficient and sustainable way. Dynamic ExF is a process consisting of reporting information as well as inferring knowledge at the same time. The essential knowledge is extracted from the information contained in the reports after that information has been formalized in a database. That knowledge can be updated gradually as new information is reported. The knowledge is inferred in the form of relevant patterns generated by a data mining algorithm. A pattern is a combination of conditions describing accidents pertaining to a same set called “class”. Every condition is made of an indicator respecting a specific value or range of values. The indicator is a risk factor or a potential cause of accident. All in all, with a dynamic ExF using a database that can be updated on a regular basis, the reports will not go to waste after being read. Instead, they will continually contribute to the knowledge inference which will progress in the context. A machine learning algorithm called Logical Analysis of Data (LAD) is integrated with the dynamic experience feedback process to ensure that the method is also suited for scarce data. Indeed, LAD proved to be efficient since the classification accuracy of the patterns generated from a 23-belt-conveyor-related accident database was adequate: between 72% and 74%. Two facts explain the choice of belt conveyors for the thesis: among all types of conveyors, they are the ones responsible of the biggest proportion of accidents (16.8%) between 1990 and 2011, according to 137 accident investigation reports from the Commission des normes, de l’équitĂ©, de la santĂ© et de la sĂ©curitĂ© du travail (CNESST) owing to conveyors; belt conveyors have the biggest ratio (8.5%) of serious and fatal accidents related to all kinds of machines, between 1999 and 2007, according to a database of the Institut de recherche Robert-SauvĂ© en santĂ© et en sĂ©curitĂ© du travail (IRSST). The 23 accident investigation reports dealt with in this thesis come from the CNESST’s Documentation Center. Analyzing the information in every report allowed for the identification of the elements describing the accidental context. Processing that information lead to a database that LAD used to generate two kinds of patterns: one for a version of the database splitting the 23 accidents into two classes: maintenance-related accidents and production-related ones; the other for a version of the 23-accident database comprising “Non fatal” and “Fatal” classes. Some of the patterns generated showed that an accident can happen due to dangerous conditions (e.g. a poor environment in the workplace), but also because of an apparently-safe condition (e.g. an existing prevention program). In that case, one should investigate the unsafe sub-factors underlying to the apparently-safe condition in order to understand the occurrence of the accident. For example, 60% of the maintenance-related accidents happened despite the presence of a prevention program. Not updating that program could be a reason why the accident happened. Other patterns showed that risk factors or causes related to the equipment, the organization, the individual or the moment explain mainly the accidents analyzed. Quantitative parameters related to the patterns, such as their coverage and their indicators frequency, enabled to start ranking the patterns as well as their indicators according to their importance (the coverage is the number of accidents a pattern characterizes). A probability of occurrence of harm estimation method associated with each pattern was developed to complete that hierarchy among the patterns with identical coverage. Such hierarchy with quantitative basis objectively guides the safety practitioner with the risks factors or accident potential causes needing to be taken care of in priority. The probability of occurrence of harm estimation uses the mass functions related to the indicators included in the pattern. It is found that the patterns representing the “Fatal” class have a higher probability compared with the ones describing the “Non fatal” class. Surprising fact because in reality, non fatal accidents (serious and non serious ones) are more frequent than fatal accidents. Since the CNESST publishes accident investigation reports only regarding serious or fatal injuries, such difference is understandable. Nevertheless, considering the sample studied for the thesis, the most severe type of accident (fatal) is also the most likely. Therefore, it is suggested that the safety practitioners from the enterprises concerned by the accidents analyzed perform the risk reduction process preventing fatalities first. The probability of occurrence of harm calculated has the potential to serve as a basis for comparison that enables to track the risk evolution. For instance, after implementing a risk reduction measure, one will be able to evaluate the effect of that measure on the probability of occurrence of harm previously calculated. The method suggested is transposable to industrial equipment other than belt conveyors. The same approach can be adopted to estimate the probability of occurrence of a hazardous event of different nature. In such case, the probability calculated can be integrated to qualitative tools to specify their labels describing the probability of occurrence of a hazardous event. That integration adds objectivity to risk estimation process. The success of that method relies on the good will of the stakeholders to bring feedback on the machinery-related risk portrait. If no stakeholder reveals information about a new state of a risk reduction measure or about a new circumstantial event, that information will never be registered in the database. Accordingly, the patterns defining the risk will never be updated, and so will not be the essential risk factors and accident potential causes, as well as the probabilities related. Consequently, outdated decision-making might be performed. A safety culture as well as a mutual trust in the enterprises is important to encourage feedback in order to improve the risk portrait and the efficiency of the risk reduction measures
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