Computer tools for integrated conceptual design

This paper outlines the conceptual design process with reference to the integrated computer-aided design tool known as Schemebuilder, and the related work of the Lancaster University Engineering Design Centre. The aim of the Lancaster EDC is to provide highly integrated support for the rapid creation and evaluation of a wide range of outline design schemes. Particular attention is paid to the design of mechatronic systems and devices.     

救捞工程中的多指标决策方法探讨

建立了基于综合权重的双基点多指标决策模型。分别从主观和客观两个方面来分析评估指标的权重,迭加得到综合权重,并利用它进行相对贴近度分析,从而判断方案的优劣,得到最佳方案,使问题的优化与决策更加科学、合理。以拖带方案的优化决策分析为例,验证了多指标决策模型的可行性,简述了它在救捞工程中的应用方法。     

Eco-architecture analysis for end-of-life decision making

In order to improve ease of disassembly and recycling of a product at its retirement stage, it is essential to design a product architecture that allows for easy disassembly and recycling. In this paper, a novel concept of eco-architecture is introduced, and the eco-architecture analysis, a design approach supporting the end-of-life decision making process, is proposed. The eco-architecture is the product architecture described from the end-of-life (EOL) viewpoint, in which a product is represented as an assembly of end-of-life modules. Not only does it prescribe an EOL strategy, but it also gives information about the connections and arrangement among EOL modules. Therefore, understanding the eco-architecture is helpful in enhancing the disassembly and recycling capabilities of an architecture design. The proposed eco-architecture analysis supports architecture improvement; it helps designers to derive the most desirable eco-architecture which entails the optimal end-of-life strategy. It also facilitates the extraction of meaningful redesign guidelines which make it possible to improve an architecture in an efficient and effective manner.     

数字化人机界面的多目标意象设计决策研究

用户的感性需求愈来愈受到设计者和企业的重视.为解决实际中多目标意象要求下数字化人机界面方案选择过程中存在的复杂性与主观性问题,提出一种三角模糊数与逼近理想解排序法相结合的模糊逼近理想解排序法(F-TOPSIS).结合某新型远程操控清障车的数字化人机界面设计,在通过运用因子分析方法获取用户对数字化人机界面典型样本的4类感性意象的基础上,应用F-TOPSIS实现了决策者多目标意象特定要求下对10个数字化人机界面设计方案的优先级排序,验证了该方法的可行性.研究表明F-TOPSIS对数字化人机界面设计方案的区分度较好,能在多目标意象需求下进行较为合理、准确的设计决策.     

Improved fuzzy ranking procedure for decision making in product design

In this paper, we present a method for ranking any number of normal fuzzy numbers using trapezoidal fuzzy numbers as a general form, where rectangular and triangular fuzzy numbers are particular cases of such a form. This general form is supported by 29 cases, which is enough to consider all the possible situations between two normal fuzzy numbers, such as trapezoidal, triangular, or rectangular. The ranking procedure is performed using four ordering criteria into a pseudo-order preference model considering the type of the fuzzy preference relation. Two examples are given to illustrate and validate the applicability and practicality of this fuzzy ranking method. A comparison and an analysis of the proposed method is presented to demonstrate its usefulness and its contribution to the improvement of the decision making processes as a result of its management of vague or imprecise information, and whether or not that information should be allowed to be entered into such processes.     

Three-level trade-off analysis for decision making in environmental engineering under interval uncertainty

A three-level trade-off analysis is proposed for decision making in environmental engineering under interval uncertainty, capable of providing both extreme and non-extreme decision alternatives at different risk levels for constraint and objective function violations. The essence of three-level trade-off analysis is the use of both modified interval linear programming and enhanced interval linear programming models to generate risk-based decision alternatives by qualitatively dividing the risk levels of the parameters in both the constraints and the objective function. The generated decision alternatives include two extremes, two appropriate values and one expected value, and two other non-extremes. The results of a numerical example and a real-world case study (Lake Qionghai Watershed, China) indicate that this procedure can support decision-making processes for stakeholders at different levels of risk to system benefits, within absolutely feasible and optimal solution spaces.     

A bill of materials-based approach for end-of-life decision making in design for the environment

Re-use, recycling or remanufacturing of products and components are good alternatives for reducing the environmental problems resulting from the huge amounts of waste currently arriving at landfills. A new approach is proposed in this paper for enhancing these alternatives from the earliest stages of product design. Given the product structure (obtained from its bill of materials (BOM)) and the joining and geometrical relationships among the components (obtained from the three-dimensional, computer-aided design representation), a model is proposed that will determine the EOL (EOL) strategy, i.e. the depth of disassembly inside the structure and the final end (re-use, recycle, remanufacture or disposal) for each disassembled part leading to the highest profit. A scatter search (SS) metaheuristic is used to determine the disassembly cost at each level of the BOM. The model presents a number of major improvements with respect to previous research. It addresses the problems of simultaneously determining both the best EOL strategy and the disassembly sequence, as well as allowing removal of components not only over the two or three Cartesian axes and affording the possibility of modifying the encountered strategy in a further step so as to fulfil other business criteria (such as disassembly time, resources availability or maximum waste generation rate).     

Provident decision making by considering dynamic and fuzzy environment for FMS evaluation

When evaluating complexity, cost and risk increase, it is difficult to make a proper decision. In such situations it is necessary to develop a model which simulates a decision maker's mind and consider both a dynamic and a fuzzy environment. In this study future oriented indices are presented which enable us to consider the effect of future changes in the index value during the decision making process. These future oriented indices are named provident indices. Also in this study to effectively integrate these multiple criteria into the decision making process, based on the analysis of the decision situation in such assessments, a suitable concept is selected. This method is based on the preference ranking organisation method for enrichment evaluations (PROMETHEE) which brings together flexibility and simplicity for the user and is therefore chosen for the enhancement towards the evaluation of fuzzy data on preferences, scores and weights. The model developed to investigate these impacts cannot perfectly reproduce all the events of the real system, but it can consider a fair number of elements of variability, which should be identified and analysed by considering present conditions and prediction about criteria values in future periods. Such a model may provide solutions with a high degree of robustness and reliability, comparable with those obtained by direct experimentation, but with a low computational cost. The uniqueness of this paper lies in two important areas: first, the incorporation of variability fuzzy and provident measures in the performance of alternatives into the decision making process; and second, is in the application of fuzzy PROMETHEE that provides the decision maker with effective alternative choices by identifying significant differences among alternatives and appropriate choices through considered future periods, and presents graphic aids for better interpretation of results. A comprehensive numerical example of a flexible manufacturing system (FMS) is provided to illustrate the results of the analysis. In a real-world manufacturing environment, the dynamics of an FMS and its stochastic characteristics require a specific approach for evaluation. This paper specifically focuses on FMSs due to the complexities involved in their proper evaluation that include factors such as high operational and managerial expertise in system implementation phases, high costs and risks. Due to these, evaluation, justification, and implementation of an FMS have been areas of major concern and importance for practitioners and researchers. In this case, various strategic, economic and operational criteria that envelop quantitative, qualitative, tangible, and intangible factors are considered.     

Integrated reconfiguration and age-based preventive maintenance decision making

The use of manufacturing system reconfiguration in conjunction with maintenance operations has not been previously reported in the literature. This research attempts to incorporate reconfiguration into Preventive Maintenance (PM) actions for improved system performance in terms of reduced total cost. This paper presents an Integrated Reconfiguration and Age-Based Maintenance (IRABM) policy and applies it to a parallel-serial manufacturing system. The expected total cost of implementing the IRABM policy is estimated and minimized through a simulation-based heuristic optimization procedure. Using this method, it is possible to systematically identify the conditions under which the integration of reconfiguration into maintenance is cost effective. In addition, numerical examples demonstrate that the manufacturing system could have a higher probability of fulfilling production requirements at a lower cost under the IRABM policy compared to the conventional age-based PM policy. The influences of the input parameters associated with reconfiguration, production, and reliability on the performance of IRABM policy also are studied.     

Robust interval linear programming for environmental decision making under uncertainty

In this study, a robust interval linear programming (RILP) method is developed for dealing with uncertainties expressed as intervals with deterministic boundaries. An enhanced two-step method (ETSM) is also advanced to solve the RILP model. The developed RILP improves upon the conventional interval linear programming (ILP) method since it can generate solution intervals within a larger feasible zone. The decision space based on ETSM contains all feasible solutions, such that no useful information is neglected. Moreover, the RILP can guarantee the stability of the optimization model due to no violation for the best-case constraints. The results also suggest that the RILP is effective for practical environmental and engineering problems that involve uncertainties.     

Bayesian inference in group judgment formulation and decision making using qualitative controlled feedback

Summary This paper considers the problem of making statistical inferences about group judgments and group decisions using Qualitative Controlled Feedback, from the Bayesian point of view. The qualitative controlled feedback procedure was first introduced by Press (1978), for a single question of interest. The procedure is first reviewed here including the extension of the model to the multiple question case. We develop a model for responses of the panel on each stage. Many questions are treated simultaneously and an autoregressive model is developed for explaining the responses of the group members as a function of the feedback. The errors are assumed to follow a matrix intraclass covariance structure. Marginal and conditional posterior distributions of the regression coefficient vector are found in both small and large samples. The broadly defined generic family of multidimensional Student-t-distribution is found to play a major role in the results.     

Developments in the use of the genetic algorithm in engineering design

The adaptive search technique known as the genetic algorithm is described and research into its application within the fields of civil, structural and mechanical engineering discussed. Attention is drawn to the potential of the structured genetic algorithm both as a high-level decision support technique during the preliminary stages of the design process and as a powerful tool for the detailed design of complex components. Problems associated with the search for global optimum solutions and design sensitivity are outlined. Increasingly efficient and cost effective hybrid approaches are envisaged which incorporate a range of adaptive search and knowledge-based techniques.     

Significance of expert competence consideration in group decision making using AHP

The question addressed in the paper is: how does the expert group size influence the importance of experts’ competence consideration while aggregating individual expert judgements using AHP? Some recent studies show that when aggregating direct cardinal and ordinal individual estimates, expert competence does not matter so significantly in cases where the number of expert group members is relatively large (more than 50 experts). The present study is aimed at clarifying the issue in case individual expert judgements are provided as pair comparisons in the fundamental scale and aggregated using AHP methodology. Expert estimates are modelled based on presumptions that they are distributed according to exponential and absolute normal distribution laws. Experiment results confirm the presumption that under large expert numbers, the competence of individual experts matters less significantly but if the number of experts in a group is relatively small, expert competence should always be taken into consideration.     

Generic research for design of made-to-order engineering products

The paper identifies those design research issues which, while being of particular interest to the made-to-order (MTO) sector, have a wide applicability. An overview of the Newcastle EDC research programme is provided and the research topics are set in the context of two themes— design strategies and design integrity. The process of adapting the results of research aimed at producing generic results in a form suitable for application to specific product types is illustrated by describing two projects in detail. Finally, the hetrogenous nature of the Newcastle EDC environment is described and particular references are made to industrial collaboration, technology transfer, training and education.     

A decision making methodology for material selection using an improved compromise ranking method

An ever increasing variety of materials is available today, with each having its own characteristics, applications, advantages, and limitations. In choosing the right material, there is not always a single definite attribute of selection and the designers and engineers have to take into account a large number of material selection attributes. This paper presents a logical procedure for material selection for a given engineering application. The procedure is based on an improved compromise ranking method considering the material selection attributes and their relative importance for the application considered. Two examples are included to illustrate the approach.     

Adaptive management with integrated decision making: an emerging tool for cumulative effects management

Adaptive management (AM) is being used as a follow-up tool within EIA/CEAM. Such uses include reducing cumulative effects uncertainties, and informing decision making on practices to minimize the incremental effects of proposed actions and the management of regional cumulative effects resulting from multiple contributors. Based upon a review of fundamental concepts, practices and case studies, the following key lessons have been identified: (1) AM can be a useful tool for coping with uncertainty in CEAM, improving the knowledge base and enhancing the effectiveness of cumulative effects mitigation and management at the project and regional level respectively; (2) decision flowcharts can facilitate the learning and necessary adaptations associated with AM programs, and such flowcharts should be both understandable and integrative in relation to developing an holistic perspective on management choices and their environmental implications; and (3) there is a primary need for comparative case studies illustrating how AM has been incorporated in NEPA compliance documents which address cumulative effects management.     

Optimization strategies in robust engineering design and computer-aided design

This paper reviews the fundamental ideas involved in robust engineering design (RED), and how they relate to computer-aided design. There are several areas of RED that may be successfully resolved by the use of statistical methods or ideas. This paper gives a general overview of several popular statistical strategies in RED and discusses how these strategies approach the statistical problems involved.     

A co-operation framework for product–process integration in engineering design

Many different studies have stressed the importance of co-operation in engineering design. This paper is based on an empirical study carried out over 18 months and based on fieldwork where the researcher worked in a design team as a mechanical engineer. The question of product–process integration is particularly critical in mechanical engineering and requires the development of specific co-operative procedures. Our results stress the importance of artefacts as intermediary objects in the design process and more specifically in the development of co-operative processes. We developed a framework centred on three conceptual levels:

• At product level, where we developed specific artefacts within a CAD environment, referred to herein as co-operating features,

• At organisation level, where we stress the importance of developing organisational learning and a new interface role,

• At actor level, where we stress the importance of developing reflective practices.

This conceptual framework aims to provide a foundation to develop instrumental settings for design co-operation.