A Fuzzy Criticality Assessment System of Process Equipment for Optimized Maintenance Management.

yesIn modern chemical plants, it is essential to establish an effective maintenance strategy which will deliver financially driven results at optimised conditions, that is, minimum cost and time, by means of a criticality review of equipment in maintenance. In this article, a fuzzy logic-based criticality assessment system (FCAS) for the management of a local company’s equipment maintenance is introduced. This fuzzy system is shown to improve the conventional crisp criticality assessment system (CCAS). Results from case studies show that not only can the fuzzy logic-based system do what the conventional crisp system does but also it can output more criticality classifications with an improved reliability and a greater number of different ratings that account for fuzziness and individual voice of the decision-makers

Predictive analytics and disused railways requalification: insights from a Post Factum Analysis perspective

Strategic decision making problems in the public policy domain typically involve the comparison of competing options by different stakeholders. This paper considers a real case study oriented toward ranking potential actions for the regeneration of disused railways in Italy. The study involves multiple con icting criteria such as an expected duration of construction works, costs, a number of potential users, and new green areas. Within this context, we demonstrate that Post Factum Analysis (PFA) coupled with Decision Aiding supports the development of robust recommendations. The role of PFA is to highlight how the actions' performances need to be modified so that the recommendation is changed in a desired way. In particular, it highlights the minimal improvements that would warrant the feasibility of some currently impossible outcome (e.g., achieving a better position in the ranking) or the maximal deteriorations that alternatives can afford to maintain some target result (e.g., not losing their advantage over some other options). The use of a focus group with both experts and participants in the decision making process provided insights on how PFA can support: (i) the creation of arguments in favour or against the respective options under analysis, (ii) understanding of the results' sensitivity with respect to possible changes in the alternatives' performances, (iii) a better informed discussion about the results among the participants in the process, and (iv) the development of new/better alternatives

Multiple Criteria Ranking and Choice with All Compatible Minimal Cover Sets of Decision Rules

We introduce a new multiple criteria ranking/choice method that applies Dominance-based Rough Set Approach (DRSA) and represents the Decision Maker's (DM's) preferences with decision rules. The DM provides a set of pairwise comparisons indicating whether an outranking (weak preference) relation should hold for some pairs of reference alternatives. This preference information is structured using the lower and upper approximations of outranking (S) and non-outranking (S c ) relations. Then, all minimal-cover (MC) sets of decision rules being compatible with this preference information are induced. Each of these sets is supported by some positive examples (pairs of reference alternatives from the lower approximation of a preference relation) and it does not cover any negative example (pair of alternatives from the upper approximation of an opposite preference relation). The recommendations obtained by all MC sets of rules are analyzed to describe pairwise outranking and non-outranking relations, using probabilistic indices (estimates of probabilities that one alternative outranks or does not outrank the other). Furthermore, given the preference relations obtained in result of application of each MC set of rules on a considered set of alternatives, we exploit them using some scoring procedures. From this, we derive the distribution of ranks attained by the alternatives. We also extend the basic approach in several ways. The practical usefulness of the method is demonstrated on a problem of ranking Polish cities according to their innovativeness

Impact et facteurs clés de l'introduction d'équipements miniers innovants : le cas d'une mine souterraine

Les entreprises minières naviguent dans un environnement économique cyclique influencé par les prix du marché. À cela, s'ajoute une pression sociale accrue au niveau des conditions de travail et de la sécurité des travailleurs. C'est donc à un contexte hautement concurrentiel que les entreprises de ce secteur sont confrontées. Afin de demeurer compétitives, l'une des solutions qu'elles privilégient est l'acquisition d'équipements innovants. Toutefois, l'introduction d'équipements innovants ne se fait pas sans heurts. Plusieurs études ont en effet démontré que l'arrivée de nouveaux équipements plus gros, plus puissants et plus sophistiqués a également entraîné des effets négatifs. Parmi ceux-ci notons, les périodes d'adaptation plus longues que prévues. Mais encore, ces équipements sont aussi en cause dans bon nombre d'accidents et de décès, et ce, tant à l'échelle internationale que chez les mines québécoises. Devant ces constats de succès mitigés, il appert fondamental de mieux comprendre les facteurs de succès lors de l'implantation d'équipements miniers innovants. Dans cette thèse nous proposons l'étude approfondie de ce sujet par une étude de cas réalisée dans une mine aurifère souterraine témiscabitibienne. Dans un premier temps, notre démarche vise à mesurer l'impact de dix projets innovants sur des indicateurs de performance en productivité et en santé et sécurité du travail (SST). Dans un deuxième temps, nous proposons l'utilisation d'un outil d'aide à la décision, l'approche des ensembles approximatifs basés sur la dominance, afin d'identifier les facteurs clés favorisant l'implantation de ces équipements innovants. Parmi les résultats obtenus, deux facteurs ont été identifiés comme les plus pertinents sur l'ensemble des indicateurs de performance étudiés, soit le niveau d'habileté requis pour maîtriser la technologie et le niveau d'acceptation de cette dernière par les opérateurs. En plus de ces deux facteurs, la qualité du siège et l'expérience des opérateurs ont également été identifiées comme pertinentes pour expliquer les résultats en SST, alors que le niveau de standardisation du nouvel équipement s'est montré pertinent pour expliquer ceux en productivité. Nos travaux permettent ainsi à notre partenaire industriel de cibler et de prioriser ses besoins pour que l'implantation d'équipements innovants entraîne dorénavant une amélioration de la performance en productivité et en SST. Bien que nos résultats proviennent et se limitent à une étude de cas, l'approche innovante et rigoureuse que nous proposons à la communauté scientifique et industrielle peut être mise en application à chaque entreprise minière souterraine désirant identifier ses propres facteurs de succès inhérents à son propre environnement. D'autres limites et perspectives offrent des pistes de recherches potentielles sur lesquelles se conclue notre thèse. À ce titre, nous proposons des indicateurs de performance supplémentaires, tels que le nombre de tonnes transportées par les camions et le taux de sévérité des blessures. De plus, une étude similaire, mais prenant en considération les accidents touchant les employés d'entrepreneurs miniers, de même que les accidents survenus lors de réparation ou de maintenance, ajouterait des connaissances complémentaires et intéressantes sur le sujet développé dans cette thèse

Advancing sustainable nanotechnology with multiple criteria decision aiding

Nanotechnology is currently emerging as the next industrial revolution. It enables the production of goods (i.e. nanoproducts, NPs) with enhanced functionalities, which have nonetheless caused mounting concerns about the potential implications they can have on the environment, economy and society. This thesis employs Multiple Criteria Decision Aiding (MCDA), one form of decision support, to aid the sustainable development of nanotechnology. The first original contribution of this doctoral research is the development of a framework of sustainability assessment criteria for NPs, through a three-phase procedure based on the MCDA process, including a literature review, a pilot and a main survey. It lead to a comprehensive framework of 68 criteria, ranked according to their relative importance, allocated to six main domain areas: (i) economic performance; (ii) environmental impacts; (iii) environmental risk assessment; (iv) human health risk assessment; (v) social implications; and (vi) technical performance. All the criteria are reliable and can be used in real case studies to increase the knowledge about the sustainability of NPs. The second original contribution presented in this thesis is a robust model (DRSA-based model) based on green chemistry principles implementation for the classification of synthesis processes of nanomaterials in preference-ordered classes. This tool was developed through knowledge elicitation techniques based on coconstructive MCDA with the collaboration of two experts (the decision makers) in synthesis of nanomaterials. The robustness of the ensuing model was assessed (and confirmed) by means of another model developed ad hoc (ELECTRE-based model), structured on an MCDA method implementing a stochastic multiple criteria classification strategy. The results confirm that MCDA is an effective decision support approach to foster sustainable development of nanotechnology, providing that the analysts who apply it take these considerations into account. They must ensure that (1) multidisciplinary teams are created to perform comprehensive and credible sustainability evaluations; (2) problem structuring and model construction are as important as (if not more important) than the results (i.e. decision recommendations) themselves; (3) identification of the appropriate MCDA method depends on the problem at hand and not vice-versa; and (4) the credibility of the decision recommendations is subject to the preferences of the decision-makers. If these considerations are accounted for, the possibility of advancing nanotechnology on a sustainable path is very concrete and realistic