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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Optimisation booléenne multiobjectif : complexité sous contraintes compilées et résolution via SAT / Multiobjective boolean optimization

Lonca, Emmanuel 26 June 2015 (has links)
L’aide à la décision a pour but d’assister un opérateur humain dans ses choix. La nécessité d’employer de telles techniques s’est imposée avec la volonté de traiter des problèmes dépendant d’une quantité de données toujours plus importante. L’intérêt de l’aide à la décision est encore plus manifeste lorsqu’on souhaite obtenir non pas une solution quelconque, mais une des meilleures solutions d’un problème combinatoire selon un critère donné. On passe alors d’un problème de décision (déterminer l’existence d’une solution) à un problème d’optimisation monocritère (déterminer une des meilleures solutions possibles selon un critère). Un décideur peut aussi souhaiter considérer plusieurs critères, et ainsi faire passer le problème de décision initial à un problème d’optimisation multicritère. La difficulté de ce type de problèmes provient du fait que les critères considérés sont généralement antagonistes, et qu’il n’existe donc pas de solution meilleure que les autres pour l’ensemble des critères. Dans ce cas, il s’agit plutôt de déterminer une solution qui offre un bon compromis entre les critères. Dans cette thèse, nous étudions dans un premier temps la complexité théorique de tâches d’optimisation complexes sur les langages de la logique propositionnelle, puis nous étudions leur résolution pratique via le recours à des logiciels bâtis pour résoudre de manière efficace en pratique des problèmes de décision combinatoires, les prouveurs SAT. / Decision aiding aims at helping a decision-maker to pick up a solution among several others. The usefulness of such approaches is as prominent as the size of the problems under consideration increases. The need of decision aiding techniques is salient when the problem does not just consist in deciding whether a solutions exists, but to find one of the best solutions according to a given criterion. In this case, the problem goes from a decision problem (decide whether a solution exists) to a single criterion optimization problem (find one of the best solutions according to a criterion). A decision-maker may even want to consider multiple criteria, which turns the initial decision problem into a multicriteria optimization problem. The main issue arising in such cases lies in the fact that the criteria under consideration are often antagonistic, which implies that there is no solution which is the best for each of the objectives. In this case, a good compromise solution is looked for. In this thesis, we first focus on the complexity of optimization requests based on a set of propositional languages. We then study the practical aspects of the resolution of such problems, using pieces of software designed for dealing with combinatorial decision problems, namely SAT solvers.
12

On the use of multicriteria ranking methods in sorting problems / Utilisation des méthodes de rangement multicritères dans les problèmes de tri

Nemery de Bellevaux, Philippe JJCP 29 November 2008 (has links)
Notre thèse est consacrée à l’étude des méthodes de rangements multicritères dans le cadre de la problématique de tri. Dans un problème de tri une personne, appelée décideur, désire assigner un objet, appelé action, à des catégories prédéfinies. Des problèmes de tri surgissent régulièrement dans la vie de tous les jours. Par exemple, un médecin ausculte son patient et sur base des symptômes observés, il assigne son patient à une catégorie de pathologies. Ainsi, le médecin peut prescrire un traitement approprié. Par ailleurs, on catégorise les cyclones tropicaux en fonction de leur vitesse, pression superficielle et de la hauteur de marée. En fonction de la catégorie du cyclone, des dégâts éventuels peuvent être prédits et des mesures de protection adéquates devront être prises. Dans un problème de tri, un décideur regroupe ainsi les actions qu’il considère similaires, à des fins descriptives, organisationnelles ou préventives. Nous supposerons en outre que le décideur exprime une relation de préférence entre les classes préalablement définies. D’autre part, les méthodes de rangement permettent de ranger les actions de la meilleure à la moins bonne. Nul étudiant ne peut nier l’existence des " rankings " d’universités. Une société ordonne les candidats à l’issue d’un entretien d’embauche. Une société désire par ailleurs établir des partenariats avec les fournisseurs les plus performants. Nous sommes tous confrontés à cette tâche délicate de ranger les actions de la meilleure à la moins bonne. Les méthodes d’aide à la décision proposent des techniques permettant à un décideur d’obtenir un rangement d’actions. L’objectif de cette thèse est d’étudier la possibilité de résoudre des problèmes de tri à l’aide de méthodes de rangement. L’approche adoptée est de ranger une action particulière par rapport à des normes ou profils définissant les catégories. L’assignation de l’action sera dès lors basée sur sa position dans ce rangement particulier. Quelles sont les hypothèses nécessaires pour un tel modèle ? Ces méthodes présentent-elles un biais ou ont-elles d’autres avantages par rapport aux méthodes de tri existantes? Est-il préférable de modéliser les catégories à l’aide de critères même si celles-ci ne présentent pas de relation de préférence ? Dans cette thèse nous donnerons des premiers éléments de réponse en développant de nouvelles méthodes de tri basées sur des méthodes de rangement existantes.
13

INTEGRATING A FREELY AVAILABLE ENVIRONMENTAL CUE AND COSTLY EXPERT ADVICE TO MAKE MORE NORMATIVE DECISIONS

Sutherland, Steven Cecil 01 August 2012 (has links)
Three experiments were conducted to identify the impact of factors associated with the environment (predictability of the environment) and factors associated with an available expert (the accuracy of the expert and the cost of the expert's advice) on the optimal utilization of the expert. Across all three experiments, participants overutilized the expert (requesting advice when advice was suboptimal) when the expert accuracy was higher and when the environment was less predictable. Conversely, participants underutilized the expert (not requesting advice when doing so was optimal) more when the environment was more predictable and the expert was less accurate. Participants showed little sensitivity to the cost of advice, further compounding the errors. Requiring participants to request advice on every training trial increased reliance on the later optional expert and led to properties of the expert primarily influencing the decision to request advice. Requiring participants to rely only on the environmental cue during training decreased overall reliance on the later optional expert and led to properties of the environment primarily influencing the decision to request advice. Requiring participants to interact with both the environment and the expert during training led to better overall decisions and to the integration of environmental cues and properties of the expert to inform the decision to request advice.
14

Helping Patients Choose Their Ideal Treatment for Achilles Tendon Ruptures: A Network Meta-Analysis and Protocol for Development and Field Testing a Patient Decision Aid

Meulenkamp, Brad 11 June 2021 (has links)
Treatment of acute Achilles tendon ruptures has long been controversial. Several treatment options exist for patient with variable harms and benefits to each. Recognizing that decision of treatment option is preference-sensitive, this thesis focused on updating the current literature on Achilles tendon rupture management to facilitate the creation of a patient decision aid. A network meta-analysis of all treatment options for acute Achilles tendon ruptures was performed. Results demonstrated that minimally invasive surgery options were associated with lower complications and lower complications requiring surgery. Return to sport was similar amongst all treatment groups. With guidance from the Ottawa Decision Support Framework and the International Patient Decision Aid Standards, a three-tiered protocol for development, alpha testing and field-testing a novel patient decision aid is outlined next. The patient decision aid will be reviewed and revised iteratively by multi-disciplinary steering group. This protocol will act as a framework for further orthopaedic patient decision aid development.
15

An Examination of Decision Aid Reliance in a Dynamic Environment

Briggs, John Whitfield 05 May 2004 (has links)
Computerized decision aids are powerful tools to assist with decision-making. Decision models are designed to incorporate and analyze available data in order to present a recommended solution to a problem. Business decision makers, including accountants, have much to gain from integrating decision support technology with their own skills and experience. Several studies have determined that there are many instances in which these decision aids perform favorably to human decision-makers. Despite this fact, studies have shown that reliance upon these aids is incomplete, even when they process data in a highly efficient manner. On the other hand, decision aids have limitations. If such a decision support system is not updated to match changing conditions, relying on the aid can lead to suboptimal decision-making. This study uses a laboratory experiment involving a managerial accounting task: prediction of manufacturing overhead costs. In the experimental scenario, a decision support system's recommended solutions become inaccurate due to a shift in environmental conditions. The first research objective is to determine whether subjects rely on the aid's advice before this change and, to their detriment, after the change. The second research objective is to examine whether the feedback environment, the timing of the decision aid's inclusion into the task, or the inherent confidence level of the task participant affect the tendency to rely on the aid in both of these environmental conditions. The results of the study provide evidence that decision-makers rely on decision aids, and are susceptible to over-reliance on them. These findings add to the results of prior studies that only examine a single trial task. Additionally, it is determined that the timing of a decision aid's recommendation can affect the degree to which it is relied upon. Next, there is evidence that feedback environment can help reliance and mitigate over-reliance. There is no evidence that task confidence affects reliance. Lastly, decision aids result in longer amounts of time used to complete the task. / Ph. D.
16

The Development and the Evaluation of a Quasi-Real Time Decision Aid Tool

Leite, Nelson Paiva Oliveira, Lopes, Leonardo Mauricio de Faria, Walter, Fernando 10 1900 (has links)
ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / In an experimental flight test campaign, the usage of a real time Ground Telemetry System (GTS) provides mandatory support for three basic essential services: a) Safety storage of Flight Tests Instrumentation (FTI) data, in the occurrence of a critical aircraft failure; b) Monitoring of critical flight safety parameters to avoid the occurrence of accidents; and c) Monitoring of selected parameters that validates all tests points. At the operational side the test ranges typically works in two phases: a) In real time where the GTS crew performs test validation and test point selection with Telemetry data; and b) In post mission where the engineering crew performs data analysis and reduction with airborne recorded data. This process is time consuming because recorded data has to be downloaded, converted to Engineering Units (EU), sliced, filtered and processed. The main reason for the usage of this less efficient process relies in the fact that the real time Telemetry data is less reliable as compared to recorded data (i.e. it contains more noise and some dropouts). With the introduction of new technologies (i.e. i-NET) the telemetry link could be very reliable, so the GTS could perform data reduction analysis immediately after the receipt of all valid tests points, while the aircraft is still flying in a quasi-real time environment. To achieve this goal the Brazilian Flight Test Group (GEEV) along with EMBRAER and with the support of Financiadora de Estudos e Projetos (FINEP) started the development of a series of Decision Aid Tools that performs data reduction analysis into the GTS in quasi-real time. This paper presents the development and the evaluation of a tool used in Air Data System Calibration Flight Tests Campaign. The application receives the Telemetry data over either a TCP/IP or a SCRAMnet Network, performs data analysis and test point validation in real time and when all points are gathered it performs the data reduction analysis and automatically creates HTML formatted tests reports. The tool evaluation was carried out with the instruction flights for the 2009 Brazilian Flight Test School (CEV). The results present a great efficiency gain for the overall Flight Test Campaign.
17

Groundwater impact assessment and protection

Eliasson, Åse January 2001 (has links)
<p>In the recent decades, therehave been frequent conflicts between groundwater waterresources and environmentally hazardous activities. Newmethodologies for aiding decision-making in groundwater impactassessment and protection areneeded and in which issues ofincreased awareness, better understanding of the groundwaterresources processes, and validation of predictive mathematicalmodels are addressed.</p><p>A framework fordecision–aid, based on predictive simulations that a)predicts the environmental impacts b) provides the totaleconomical value c) visualises the impacts and the groundwaterproperties and d) describes the uncertainties in the results isproposed herein. The framework can be applied in environmentalimpact assessments, strategic environmental assessments andprotection and management of water resources. The results ofthe model are used as feedback for determining new scenarios,depending on the required uncertainties, and if the plannedactivity is sustainable, and/or fulfils the legislative andpolicy measures. This framework is applied to a particular casestudy, Nybroåsen, in the south-eastern part of Sweden,where the highway E22 is constructed through the importantglaciofluvial esker aquifer, passing the protection zone of thewater supply for the Kalmar municipality.</p><p>The impacts from the new highwayand the existing road have been predicted by two-dimensionalphysically based time-variant flow and solute groundwatermodelling. The results, breakthrough curves of contaminantconcentration in wells and maps of concentration distributions,as well as travel times, flow paths, and capture zones forwells determined by particle tracking have been presented.</p><p>The constructed model of theNybroåsen study area was calibrated by comparing observedand simulated groundwater levels for 15 observation wells forten years of measurements. The model has been evaluated bothgraphically and numerically and the calibration target wasfulfilled for 13 of the 15 observation wells. The model workincludes investigations of the catchment information, a waterbalance study, simulation of the groundwater recharge,consideration of the unsaturated zone by a numerical columnsimulation, and sensitivity analysis.</p><p>From the sensitivity analysis ofthe flow and transport parameters, it has been shown that theuncertainties are mainly due to the hydraulic conductivity.Comparison of the derived conductivity from the steady-stateautomatic calibration and the time-variant calibration showedthat there are major differences in the derived parameters,which illustrates the importance of a time dependentcalibration over both wet and dry periods and in more than onepoint in the area of interest of the model predictions.</p><p>In addition, a multi-criteriadecision analysis has been carried out for four roadalternatives (including the new highway E22) and the existingroad in the case study concerned. The multi-criteria decisionaid is applied as an illustration of how it can be used in thestudy area to identify a) interest groups of actors and theirconcerns b) ranking of alternative road scenarios according toactors’preferences and c) coalition groups of actors<i>i.e.</i>groups that have similar views with regard to theroad alternatives.</p><p><b>Keywords:</b>Physically-based groundwater modelling,contamination, flow and solute transport, glaciofluvialdeposits, Nybroåsen, Sweden, and multi-criteriadecision-aid.</p>
18

New methodological perspectives on PROMETHEE methods

Van Assche, Dimitri 03 June 2019 (has links) (PDF)
A few methodological contributions to the PROMETHEE method, essentially based on 3 articles:-FlowSort parameters elicitation based on categorization examples;-PROMETHEE is Not Quadratic: An O (qnlog (n)) Algorithm;-Lexicographic constrained multicriteria ordered clustering. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished
19

Characterizing community detection algorithms and detected modules in large-scale complex networks / Évaluation de structures de communautés

Dao, Vinh Loc 17 December 2018 (has links)
La détection de communauté est une technique qui décompose des graphes en sous graphes densément connectés, ce qui est particulièrement utile dans le cas de (très) grands réseaux complexes dont la visualisation est difficile. De très nombreuses méthodes, très variées, ont été proposées ces dernières années. Dans un contexte où aucun consensus n’émerge autour de la notion même de communauté, ces méthodes provoquent de multiples discussions scientifiques autour de la qualité de leur résultat. Dans cette thèse, nous proposons plusieurs types d’évaluation comparative et approfondie de 16 méthodes bien connues de l’état de l’art ainsi que la caractérisation exhaustive des structures communautaires découvertes dans des réseaux réels variés provenant de domaines différents. Nos résultats — méthodes et analyses —constituent un début de boîte à outils pour l’analyste bien en peine de choisir la méthode adaptée à son étude. / Community detection is a technique used to separate graphs into several densely connected groups of vertices, especially powerful when visualization techniques are infeasible for large-scale structures of networks. Thanks to aplethora of potential applications in the golden age of social interaction, many detection techniques have been invented in the last decades. Their performance in discovering significant structures has been a hot topic in the network science community since there is still no consensus on what good communities are. In this dissertation, we invite readers to go through several comprehensive analyses of various state-of-the-art community detection methods as well as modular structures of real networks belonging to a large variety of domains. Our results provide intuitive illustrations of community structures and useful information that helps readers to choose their context-based rule-of-thumb solution.
20

Une approche globale pour étudier l'externalisation en phase de conception de produits industriels : une application à un contexte dans l'industrie pétrolière / A general approach to address outsourcing in the design phase of industrial products : application to an industrial context in the petroleum services industry

Dandache, Moustapha 31 January 2012 (has links)
Les entreprises de l’industrie de services pétroliers font face à une croissante incertitude de leur marché, de clients de plus en plus exigeants et une compétition plus dure. Les clients requièrent des données de plus en plus précises pour l’exploration des réserves pétrolières tout en voulant explorer des zones plus profondes et plus contraignantes. Dans ce contexte, les entreprises qui fournissent des services pour l’industrie pétrolière doivent développer des outils d’exploration plus complexes et plus innovants. Par conséquence les producteurs d’équipements (conception et fabrication) ne peuvent plus compter uniquement sur des ressources internes à l’entreprise et doivent intégrer l’externalisation à leurs processus de développement internes. Dans les années 80 et 90 l’externalisation s’est fortement répandue dans les services de support et dans la fabrication au sein des producteurs d’équipements. A nos jours ces entreprises cherchent à impliquer les fournisseurs le plus en amont possible dans le cycle de vie de leurs produits en faisant de l’externalisation depuis la phase de conception. Les motivations derrière l’externalisation en phase de conception sont l’accès aux connaissances technologiques externes à l’entreprise, la flexibilité dans le développement de nouveaux produits, l’adaptation à des charges de travail cycliques. Les entreprises ne veulent pas en même temps s’exposer aux risques de fuite de connaissances (à la concurrence), de dépendance des fournisseurs tout en maintenant leur avantage compétitif sur le marché. Dans nos travaux de recherche nous proposons un modèle général pour l’externalisation en phase de conception qui permet à une entreprise de traiter d’une façon intégrée les aspects stratégiques et opérationnels liés à l’externalisation. Ce modèle permet de créer de la valeur ajoutée à l’entreprise à travers les processus d’externalisation de la conception tout en facilitant l’intégration de l’externalisation aux processus internes de l’entreprise. En collaboration avec un industriel leader du marché de services aux entreprises pétrolières nous avons réalisé un audit industriel de son entité de production d’outils de mesure de pour comprendre ses pratiques autour de l’externalisation. Nous avons aussi réalisé une revue de la littérature sur l’externalisation. Nous avons développé un processus général qui traite l’externalisation sur plusieurs niveaux de l’entreprise. Nous avons identifié un niveau stratégique où des sujets plus longs termes sont traités et un niveau opérationnel où sont adressés des sujets spécifiques aux projets concernés. Une couche de type système d’information permet l’intégration entre ces 2 niveaux et facilite la communication entre les différents niveaux de l’entreprise et entre l’entreprise et les fournisseurs. Nous avons plus particulièrement étudié la prise de décision (Make or Buy) qui est un sujet central de l’externalisation. Nous avons identifié une liste de points de vue qui constitue une première base des sujets à prendre en compte lors de la décision d’externalisation. En s’appuyant sur la littérature sur l’aide à la décision multicritères nous avons proposé un modèle d’aide à la décision basé sur la méthode MACBETH pour supporter le processus décisionnel que nous proposons. La collaboration étroite avec les ingénieurs et les chefs de projet de l’entreprise avec laquelle nous avons travaillé et la co-construction de nos propositions avec le terrain peut constituer une première validation des résultats de nos travaux de recherche. / The oil and gas industry is facing increased market uncertainty, more demanding clients and a harsher competition. Clients are seeking increasingly precise exploration data while digging deeper for reservoirs. In this context, oil and gas industry service providers need to develop more complex and innovative exploration tools. Consequently, equipment producers (design and manufacturing) can no longer rely on internal capabilities and need to integrate outsourcing into their product development process. The 80’s and 90’s witnessed a large-scale trend of outsourcing in support services and manufacturing from equipment producers. Nowadays these firms are looking to involve suppliers earlier by introducing outsourcing as early as product design. They are seeking design outsourcing to gain access to new technological knowledge outside the firm boundaries, maneuverability in new product development and to manage cyclical work load. At the same time they want to prevent exposure to risks of knowledge leakage and dependency on suppliers while maintaining a competitive advantage. In our research project, we propose a global model for design outsourcing that would allow a firm to address both strategic and operational issues related to outsourcing. This model enables the firm to create value from design outsourcing while easily integrating it to its operational processes. First, we audited a major equipment producer in the oil and gas industry in order to understand outsourcing practices. We also performed an extensive literature review about outsourcing. Accordingly, we developed a general process that addresses design outsourcing at several levels of a firm. We identified a strategic level where long term issues are tackled and an operational level where project specific issues are tackled. These levels are integrated through an information system layer that facilitates communication across different levels of the firm and between the firm and the supplier. Since the make or buy decision is integral to outsourcing, we gave it special attention; we identified a generic list of attributes that constitute a first checklist for decision makers when addressing the make or buy decision. Using a multi-criteria decision aid methodology we also developed a MACBETH-based decision aid model to support the decision making process. Close collaboration with field engineers and managers at the industrial firm gave us first hand validation of our proposals.

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