Supporting product architecture design using computational design synthesis with network structure constraints

A product’s architecture can affect many aspects of product and process quality, from technical performance to the design effort required, production costs and satisfaction of later lifecycle requirements. This paper explores how computational tools can augment creative methods in product architecture design. Based on an empirical study aiming to understand the context of product architecture design, a new computational method is proposed to support this activity. In the method, product architectures—networks of components linked by connections—can be synthesised using constraints on the structure of the network to define the set of ‘realisable’ architectures for a product. An example illustrates how the method might be used on a real design problem, including the construction of an appropriate set of network structure constraints and the identification of promising architectures from the synthesis results. Preliminary evaluation of the method’s usability, assessed through a laboratory experiment, and its utility, assessed through application to a real historical design problem, supported by initial validation by an engineer from the case study company, suggests that the method has value for engineering design practice.     

A methodology of integrating affective design with defining engineering specifications for product design

Affective design and the determination of engineering specifications are commonly conducted separately in early product design stage. Generally, designers and engineers are required to determine the settings of design attributes (for affective design) and engineering requirements (for engineering design), respectively, for new products. Some design attributes and some engineering requirements could be common. However, the settings of the design attributes and engineering requirements could be different because of the separation of the two processes. In previous studies, a methodology that considers the determination of the settings of the design attributes and engineering requirements simultaneously was not found. To bridge this gap, a methodology for considering affective design and the determination of engineering specifications of a new product simultaneously is proposed. The proposed methodology mainly involves generation of customer satisfaction models, formulation of a multi-objective optimisation model and its solving using a chaos-based NSGA-II. To illustrate and validate the proposed methodology, a case study of mobile phone design was conducted. A validation test was conducted and the test results showed that the customer satisfaction values obtained based on the proposed methodology were higher than those obtained based on the combined standalone quality function deployment and standalone affective design approach.     

Cognitive research: Uncovering how designers design; cognitive modeling: Explaining and predicting how designers design

In this paper we describe: 1) A research approach that can produce cognitive models of the design process and 2) A particular model that illustrates the approach.Cognitive models describe the complex behaviors required to solve engineering problems in terms of underlying functional mechanisms. Because the models describecognitive systems at the level of functional mechanisms, they can generate explanations and predictions about the behaviors being studied. This makes the model useful to theorists; it also provides insights concerning support and teaching tools for practitioners.To illustrate our approach we present a model of learning to program by analogy. Within the model we describe mechanisms that simplify the processes of mapping, evaluating and debugging newly acquired knowledge in a complex domain. We also discuss the theoretical and practical implications of the model.     

Tapping into past design experiences: knowledge sharing and creation during novice–expert design consultations

Designing is a knowledge-intensive activity. For novice design engineers, an important means of acquiring knowledge is to consult experienced colleagues. We observed novice?Cexpert consultations as part of three engineering projects in a large aerospace company. Seven meetings were analysed in detail regarding the design activity, the content, and the form of interaction. Although the meetings were initiated for the purpose of information seeking, this process amounted to only 8% of the time compared to knowledge creation between novices and experts (47% of meeting time), and contextual information sharing (45% of meeting time). Both experts and novices were found to contribute equally and interactively to the discussion and analysis of solutions. The analysis showed how the processes alternated in the meetings. We identified tentative patterns on how these consultation processes change over the course of the design process phases. The micro-level analysis of the design activities and form of interaction provided a deeper understanding of how the consultation processes are discursively produced by the experts and novices. Finally, implications for design engineering practitioners are derived and suggestions for further research are provided.     

Space-based parallel program design process with high-level communication channels

Abstract

In this research, we reduce design complexity of parallel programs by performing the design task at the high level. We devised a formalism of the parallel program design process to support space-based parallel program design. In this formalism, program designs are captured in entity spaces. Entity spaces, including data spaces, tasks, etc. can be subdivided and freely distributed into logical node clusters that are assigned to processes. We designed high-level communication channels for communication among divided subtasks in a parallel program for space-based communication integration. Supported program models range in single program multiple data, multiple program multiple data, and their hybrid model. We designed single-space and cross-space high-level communication channels with various communication topologies. They are specified externally and decoupled from a parallel program. This makes the program logical and easily designed and reused. A practical example is used for illustrating the design process.     

A novel systematic method to evaluate computer-supported collaborative design technologies

Selection of suitable computer-supported collaborative design (CSCD) technologies is crucial to facilitate successful projects. This paper presents the first systematic method for engineering design teams to evaluate and select the most suitable CSCD technologies comparing technology functionality and project requirements established in peer-reviewed literature. The paper first presents 220 factors that influence successful CSCD. These factors were then systematically mapped and categorised to create CSCD requirement statements. The novel evaluation and selection method incorporates these requirement statements within a matrix and develops a discourse analysis text processing algorithm with data from collaborative projects to automate the population of how technologies impact the success of CSCD in engineering design teams. This method was validated using data collected across 3 years of a student global design project. The impact of this method is the potential to change the way engineering design teams consider the technology they use and how the selection of appropriate tools impacts the success of their CSCD projects. The development of the CSCD evaluation matrix is the first of its kind enabling a systematic and justifiable comparison and technology selection, with the aim of best supporting the engineering designers collaborative design activity.     

The impact of client choice on preventive healthcare facility network design

In contrast with sick people who need urgent medical attention, the clientele of preventive healthcare have a choice in whether to participate in the programs offered in their region. In order to maximize the total participation to a preventive care program, it is important to incorporate how potential clients choose the facilities to patronize. We study the impact of client choice behavior on the configuration of a preventive care facility network and the resulting level of participation. To this end, we present two alternative models: in the “probabilistic-choice model” a client may patronize each facility with a certain probability, which increases with the attractiveness of the available facilities. In contrast, the “optimal-choice model” stipulates that each client will go to the most attractive facility. In this paper, we assume that the proximity to a facility is the only attractiveness attribute considered by clients. To ensure the quality of care, we impose a bound on the mean waiting time as well as a minimum workload requirement at each open facility. Subject to a total capacity limit, the number of open facilities as well as the location and the capacity (number of servers) of each open facility is the main determinant of the configuration of a facility network. Both models are formulated as a mixed-integer program. To solve the problems efficiently, we propose a probabilistic search algorithm and a genetic algorithm. Finally, we use the models to analyze the network of mammography centers in Montreal.     

Integrated product development

Manufacturing and design are very closely related. The manufacturing capabilities available impact the scope of design, while design for manufacturing ensures the economic success of the products. Furthermore, the major goals of firms in the nineties are to significantly reduce product costs and time to market (TTM). To meet these goals, quality product designs that meet customers’ needs have to be developed. Design methods such as Quality Function Deployment and Pugh’s concept selection technique have been used to significantly improve engineering design processes. Developed as separate tools, however, they are difficult to integrate and coordinate in the total design process, since the relationship of the two methods is often unclear. This paper demonstrates, through a case study, that these methods are in fact results of a similar underlying concept. Design problems and solutions are unified by the concept of engineering models. An engineering model is a set of equations that relates the design variables to the performance metrics used to quantify performance of a product. Together with the engineering models, Quality Function Deployment and Pugh’s concept selection technique have been used in the design and development of a hematology machine from concept to prototype.     

Post-Certification Engineering Taxonomy and Task Value Optimization in the Aerospace Industry

Abstract:

This article proposes a novel taxonomy of post-certification engineering activities as a first step toward true lean product development (PD). Relying on key notions developed in a novel lean engineering performance model, the authors compare the leanness of post-certification versus pre-certification tasks for the design of aerospace parts. Discrete event simulation and integer linear programming models are developed to help ascertain the influence of factors such as multitasking, concurrency, task size, task value, and post-certification budget decision making on lean engineering PD performance. The models developed provide the foundation for enhanced PD performance and the establishment of optimal PD process parameters.     

Developing a fuzzy proportional–derivative controller optimization engine for engineering design optimization problems

In real world engineering design problems, decisions for design modifications are often based on engineering heuristics and knowledge. However, when solving an engineering design optimization problem using a numerical optimization algorithm, the engineering problem is basically viewed as purely mathematical. Design modifications in the iterative optimization process rely on numerical information. Engineering heuristics and knowledge are not utilized at all. In this article, the optimization process is analogous to a closed-loop control system, and a fuzzy proportional–derivative (PD) controller optimization engine is developed for engineering design optimization problems with monotonicity and implicit constraints. Monotonicity between design variables and the objective and constraint functions prevails in engineering design optimization problems. In this research, monotonicity of the design variables and activities of the constraints determined by the theory of monotonicity analysis are modelled in the fuzzy PD controller optimization engine using generic fuzzy rules. The designer only needs to define the initial values and move limits of the design variables to determine the parameters in the fuzzy PD controller optimization engine. In the optimization process using the fuzzy PD controller optimization engine, the function value of each constraint is evaluated once in each iteration. No sensitivity information is required. The fuzzy PD controller optimization engine appears to be robust in the various design examples tested.     

Chemical process design using heuristics in the context of pollution prevention

 Compiled in sufficient quantities, the effectiveness of design heuristics (rules-of-thumb) to help identify pollution prevention alternatives has been demonstrated. In this paper, a core structure of associated heuristics and procedures developed using chemical engineering principles are presented for use during conceptual as well as retrofit design. The approach is applicable for continuous bulk processes and has been encoded in the software P2TCP (Pollution Prevention Tool for Continuous Processes), a prototype expert system, to help develop inherently cleaner processes. Unlike hierarchical or step-wise design techniques, heuristics (knowledge based rules) are presented that help identify potential unit operations and analyze their interactions independently within the reaction and separation systems of a chemical process. Interactions between the reaction and separation systems are then taken into account to further reduce the number of overall flow diagrams requiring subsequent evaluation. Future extensions to the knowledge base and combination with complimentary tools like process simulation packages are envisioned. Received: 16 April 1999 / Accepted: 27 April 1999     

具有复杂内腔和外形的斗齿快速逆向设计

为了获得某型挖掘机斗齿点云逆向造型的实体化模型和CAD工程图样,研究了斗齿点云快速实体化的方法.采用基于“曲面重构-实体化-工程图”的逆向设计途径,提出把对精度要求高的内腔和销孔部位及对精度要求一般的斗齿外形分别用Imageware及Geomagic Studio软件完成曲面重构和基于Pro/E软件完成曲面合并和实体化的逆向策略,介绍了斗齿点云的数据分割、曲面重构与合并、实体化以及其工程图获取过程中的主要过程和方法.研究结果表明：对于型面数量多而复杂的斗齿,曲面逆向工具的选取及点云的数据分割方法是否得当是决定曲面和实体模型重建效率和成败的关键,通过恰当选择逆向策略和工具,合理简化点云的分割、曲面重构与合并以及实体模型的建立等,可显著提高逆向设计效率.     

Design theory: a foundation of a new paradigm for design science and engineering

In recent years, the works on design theory (and particularly the works of the design theory SIG of the design society) have contributed to reconstruct the science of design, comparable in its structure, foundations and impact to decision theory, optimization or game theory in their time. These works have reconstructed historical roots and the evolution of design theory, conceptualized the field at a high level of generality and uncovered theoretical foundations, in particular the logic of generativity, the “design-oriented” structures of knowledge, and the logic of design spaces. These results give the academic field of engineering design an ecology of scientific objects and models, which allows for expanding the scope of engineering education and design courses. They have contributed to a paradigm shift in the organization of R&D departments, supporting the development of new methods and processes in innovation departments, and to establishing new models for development projects. Emerging from the field of engineering design, design theory development has now a growing impact in many disciplines and academic communities. The research community may play a significant role in addressing contemporary challenges if it brings the insights and applicability of design theory to open new ways of thinking in the developing and developed world.     

Fuzzy multiple objective decision making approach to prioritize design requirements in quality function deployment

Quality function deployment (QFD) is a customer-oriented design tool for developing new or improved products to increase customer satisfaction by integrating marketing, design engineering, manufacturing, and other related functions of an organization. QFD focuses on delivering value by taking into account customer needs and then deploying this information throughout the development process. Although QFD aims to maximize customer satisfaction, technology and cost considerations limit the number and the extent of the possible design requirements that can be incorporated into a product. This paper presents a fuzzy multiple objective programming approach that incorporates imprecise and subjective information inherent in the QFD planning process to determine the level of fulfilment of design requirements. Linguistic variables are employed to represent the imprecise design information and the importance degree of each design objective. The fuzzy Delphi method is utilized to achieve the consensus of customers in determining the importance of customer needs. A pencil design example illustrates the application of the multiple objective decision analysis.     

Understanding design: Artificial intelligence as an explanatory paradigm

A substantial part of the intellectual content of what H A Simon called the ‘sciences of the artificial’ is contained in the activity we calldesign. A central aim ofdesign theory is to construct testable, explanatory models of the design process that will serve to enhance our understanding of how artifacts are, or can be, designed. In this paper, we discuss how some of the basic concepts underlying the discipline ofartificial intelligence (ai) can serve to provide anexplanatory paradigm for understanding design. We present an AI-based model of the design process and describe some of the implications of this model for our understanding of design — including that aspect of it we call ‘invention’.     

Measuring information flow in the detailed design of construction projects

Waste in engineering design has many facets, from partial utilization of the solution space, to wasteful management of design resources, and creation of erroneous and ineffective design documents. In the detailed construction documentation design phase of construction projects with teams comprising multiple independent designers, slow and interrupted information flows lead to significant waste. Applying lean principles, such as reducing batch sizes, cycle times and work in progress inventories, to the management of information flows may improve processes and reduce waste in this phase of the design process, but the lack of a method for measuring the volume, rate and effectiveness of information flow is an obstacle to research. This study proposes measuring the flow of information in the process of detailed design where construction documents are prepared. Measures and indices of flow were formulated based on examination of empirical data compiled by monitoring flows of design information in the detailed design stage of each of fourteen construction projects. Data describing the flows was drawn from the database logs created through practitioners’ use of a project extranet service. Indices for identifying information flow bottlenecks, large batch sizes and accumulation of work in process were computed and validated for four of the projects by comparing them with the results of independent observations of design coordination meetings. An index for measuring rework was also computed but could not be validated. The indices and information flow graphs are intended to assist in identifying faults or bottlenecks in the process either as they happen or in retrospective study, indicating disruptions in the information flow. As such, they are important tools for research of engineering design and may be of practical use in design management if incorporated in future online design management tools.     

Identifying subassemblies and understanding their functions during a design review in immersive and non-immersive virtual environments

Design review (DR) is a product development (PD) activity used to inspect the technical characteristics of a design solution. Immersive virtual reality (IVR) technology enables the presentation of spatial information and interaction with 3D CAD models inside an immersive virtual environment (IVE). Such capabilities have shown the potential to mitigate the cognitive load needed for the visual perception of spatial information and, consequently, enhance design understanding and DR performance. Thus, an increasing number of studies have explored the effect of IVR technology on DR activities in different domains. However, determining when the implementation of IVR technology rather than a conventional user interface for DRs in mechanical engineering PD projects will be beneficial remains unclear. Hence, a conceptual DR experimental study was conducted to investigate the differences in the ability of engineering students to identify mechanisms and understand their functions when a design solution for a technical system is presented in an IVE by IVR technology and in a non-immersive virtual environment (nIVE) by a conventional user interface (monitor display, keyboard, and mouse). Data were collected by performing DR tasks and having participants complete a prior experience questionnaire, presence questionnaire, and mental rotations test. Findings of the study indicate that IVR does not support an enhanced ability of engineering students to identify mechanisms and understand their functions compared with a conventional user interface.