Comparison of different Multiple-criteria decision analysis methods in the context of conceptual design: application to the development of a solar collector structure

At each stage of the product development process, the designers are facing an important task which consists of decision making. Two cases are observed: the problem of concept selection in conceptual design phases and, the problem of pre-dimensioning once concept choices are made. Making decisions in conceptual design phases on a sound basis is one of the most difficult challenges in engineering design, especially when innovative concepts are introduced. On the one hand, designers deal with imprecise data about design alternatives. On the other hand, design objectives and requirements are usually not clear in these phases. The greatest opportunities to reduce product life cycle costs usually occur during the first conceptual design phases. The need for reliable multi-criteria decision aid (MCDA) methods is thus greatest at early conceptual design phases. Various MCDA methods are proposed in the literature. The main criticism of these methods is that they usually yield different results for the same problem. In this work, an analysis of six MCDA methods (weighed sum, weighted product, Kim & Lin, compromise programming, TOPSIS, and ELECTRE I) was conducted. Our analysis was performed via an industrial case of solar collector structure development. The objective is to define the most appropriate MCDA methods in term of three criteria: (i) the consistency of the results, (ii) the ease of understanding and, (iii) the adaptation of the decision type. The results show that TOPSIS is the most consistent MCDA method in our case

Multi-Criteria Optimization Of Textile Production By Analysis Of Machine Stoppage

This article presents the application of multi-criteria optimization in textile production. Indeed, with globalization and technological development, only industries that manage to maximize their production and minimize the lost of time are competitive. This work then relates the application of multi-criteria optimization combined with the FMEA method which is the analysis of failure modes, their effects and their criticalities as well as the Analytic Hierarchy Process (AHP) method to maximize production in the field textiles and reduce machine downtime. To do this, we considered 3 sub-objectives which are economic viability, the service provided to the consumer and the impact on the environment. From these 3 sub-objectives, 11 criteria are studied at level 2 of the objective hierarchy tree, namely the cost of fabric, the cost of energy, costs linked to the unavailability of systems, maintenance costs and repair, the cost of replacing components, the quality and quantity of fabrics produced, the delivery time

Computational Evolutionary Embryogeny

Evolutionary and developmental processes are used to evolve the configurations of 3-D structures in silico to achieve desired performances. Natural systems utilize the combination of both evolution and development processes to produce remarkable performance and diversity. However, this approach has not yet been applied extensively to the design of continuous 3-D load-supporting structures. Beginning with a single artificial cell containing information analogous to a DNA sequence, a structure is grown according to the rules encoded in the sequence. Each artificial cell in the structure contains the same sequence of growth and development rules, and each artificial cell is an element in a finite element mesh representing the structure of the mature individual. Rule sequences are evolved over many generations through selection and survival of individuals in a population. Modularity and symmetry are visible in nearly every natural and engineered structure. An understanding of the evolution and expression of symmetry and modularity is emerging from recent biological research. Initial evidence of these attributes is present in the phenotypes that are developed from the artificial evolution, although neither characteristic is imposed nor selected-for directly. The computational evolutionary development approach presented here shows promise for synthesizing novel configurations of high-performance systems. The approach may advance the system design to a new paradigm, where current design strategies have difficulty producing useful solutions

Modélisation et optimisation en conception multi-objectifs

Les problèmes de modélisation et d'optimisation en conception sont caractérisés par des spécificités propres à l'activité de conception : modélisation de connaissances subjectives, optimisation multi objectifs, problèmes hybrides (continu discret), taille de l'espace de recherche de solutions. Cet article propose d'aborder différentes techniques pour modéliser et résoudre ce type de problème. Ces méthodes et outils seront illustrés sur un exemple représentatif d'une complexité de niveau industriel

Robust Design Review Conversations

Design reviews and executive conversations at the point of strategic decision-making share an important outcome: they both result in the (nearly) irrevocable allocation of resources to pursue a design concept or strategic option. Our study aims to contribute to the strategic decision-making scholarship by investigating the robustness of these conversations. We define a robust design review conversation as one in which the participants discuss evidence in favor of and against the option and at the same time propose new hypotheses to explain or resolve the evidence in favor of and against the option, hypotheses that can eventually be tested. We describe this second process as generative sensing. Whereas the first process is likely to rely on deductive reasoning from established rules to a definitive conclusion, the second is likely to rely on abductive reasoning, a form of reasoning that generates new hypotheses that are candidate parsimonious explanations for the evidence. We analyze and compare the design review conversations from a junior-level undergraduate course in industrial design and an entrepreneurship course. We find more instances of generative sensing in the industrial design review sessions than in the entrepreneurship project presentations. We believe that generative sensing serves three instrumental purposes: to resolve problems; to provide signals on option quality; and, to test the commitment to the present design concept

A linguistic approach to assess the dynamics of design team preference in concept selection

This paper addresses the problem of describing the decision-making process of a committee of engineers based upon their verbalized linguistic appraisals of alternatives. First, we show a way to model an individual’s evaluation of an alternative through natural language based on the Systemic-Functional Linguistics system of APPRAISAL. The linguistic model accounts for both the degree of intensity and the uncertainty of expressed evaluations. Second, this multi-dimensional linguistic model is converted into a scalar to represent the degree of intensity and a probability distribution function for the stated evaluation. Finally, we present a Markovian model to calculate the time-varying change in preferential probability, the probability that an alternative is the most preferred alternative. We further demonstrate how preferential probability toward attributes of alternatives correspond to preferential probability toward alternatives. We illustrate the method on two case studies to highlight the time-variant dynamics of preferences toward alternatives and attributes. This research contributes to process tracing in descriptive decision science to understand how engineers actually take decisions.National Science Foundation (U.S.) (Award CMMI-0900255

Herramienta para la evaluación de la accesibilidad universal al interior de viviendas

El presente estudio propone una herramienta para evaluar la accesibilidad universal al interior de viviendas, presentando un novedoso modelo cuantitativo para evaluar la accesibilidad de edificios para compradores o arrendatarios. Para ello se emplea un análisis multicriterio que reagrupa indicadores con diferentes unidades y escalas utilizando un único grado de accesibilidad para cuatro principales pilares: Autonomía, Movilidad, Confort y Seguridad. El método de evaluación fue aplicado en 35 departamentos en venta en el casco urbano de Santiago de Chile. Este trabajo muestra la aplicación y resultados de 4 departamentos. Los resultados de la evaluación se presentan de forma visual con un gráfico de barras circulares y una calificación final en escala de letras de la F a la A. En general, se observa que los cuatro departamentos tienen un bajo grado de accesibilidad (letra F a la D). Y el pilar de Autonomía es claramente el pilar más bajo de los departamentos seleccionados