A geometric modelling framework for conceptual structural design from early digital architectural models

Computer support for conceptual structural design is still ineffective. This is due, in part, to the fact that current computer applications do not recognize that structural design and architectural design are highly interdependent processes, particularly at the early stages. The goal of this research is to assist structural engineers at the conceptual stage with early digital architectural models. This paper presents a geometric modeling framework for facilitating the engineers’ interactions with architectural models in order to detect potential structural problems, uncover opportunities, respect constraints, and ultimately synthesize structural solutions interactively with architectural models. It consists of a process model, a representation model and synthesis algorithms to assist the engineer on demand at different stages of the design process. The process model follows a top-down approach for design refinements. The representation model describes the structural system as a hierarchy of entities with architectural counterparts. The algorithms rely on geometric and topologic relationships between entities in the architectural model and a partial structural model to help advance the synthesis process. A prototype system called StAr (Structure-Architecture) implements this framework. A case study illustrates how the framework can be used to support the conceptual structural design process.     

Routine design with information content and fuzzy quality function deployment

Design can be classified into four basic categories: creative design, innovative design, redesign, and routine design. This paper describes a method for performing routine design by utilizing information content and fuzzy quality function deployment. An attempt has been made to associate with each critical characteristic of a product a value representing the information content, which is a measure of probability that a system can produce the parts as specified by the designer, using a specific manufacturing technology for making the parts. Once the information content of each design alternative is computed, the system will select an alternative with the minimum amount of information content. The proposed method provides us with a means for solving the critical design evaluation and validation problem.     

Using an expert system for design diagnosis and design synthesis

Abstract This paper describes the concepts which allow an expert system to be used for both design diagnosis and design synthesis. An example of the implementation of these concepts is presented in the domain of preliminary design of domestic kitchens in the expert system PREDIKT. PREDIKT carries out both design diagnosis and design synthesis using the same knowledge base and utilises an existing expert system shell which has forward- and backward-chaining capabilities. The significance of graphical interaction with expert systems in design domains is demonstrated.     

Semantic Web based innovative design knowledge modeling for collaborative design

This paper describes a study about how to use the Semantic Web technologies for innovative design knowledge modeling in a multi-agent distributed design environment. Semantic Web based knowledge modeling for innovative design is proposed as prelude to the meaningful agent communication and knowledge reuse for collaborative work among multidisciplinary organizations. A model for innovative design is proposed at first, based on which a knowledge schema is brought forward. For sharing the design knowledge among an internet-based or distributed work team, even globally, A RDF-based knowledge model is presented to realize its representation on Semantic Web. A Semantic Web based repository for innovative design and its API for topper Semantic Web applications have been also constructed. The proposed knowledge modeling extends traditional product modeling with capabilities of innovative design, knowledge sharing and distributed problem solving, and is employed as a content language within the messages in the proposed multi-agent system architecture. The proposed approach is viewed as a promising knowledge management method that facilitates the implementation of computer supported cooperative work in innovative design of Semantic Web applications.     

A model-driven engineering framework for embedded systems design

This work presents a Model-Driven Engineering (MDE) framework to improve embedded system design. The framework adopts concepts from MDE for the automatic generation of a control and data flow internal representation, starting from the functional specification of an embedded application described using UML class and sequence diagrams. By means of transformations rules applied on the UML model of the embedded system, an MOF-based (Meta Object Facility is a standard representation for meta-models and models proposed by OMG) internal representation is automatically obtained, which is iteratively mapped into a hardware/software implementation by means of model transformations. This mapping is optimized by a design space exploration (DSE) method based on a categorical graph product. The model transformations have also as input a platform model, which specifies the available hardware, software and interface resources, and produce an implementation model, on which software synthesis, communication synthesis and high-level synthesis algorithms are applied to generate the final implementation. A case study is described to illustrate the application of the framework.     

The design and realization of CoViD: a system for collaborative virtual 3D design

Many important decisions in the design process are made during fairly early on, after designers have presented initial concepts. In many domains, these concepts are already realized as 3D digital models. Then, in a meeting, the stakeholders for the project get together and evaluate these potential solutions. Frequently, the participants in this meeting want to interactively modify the proposed 3D designs to explore the design space better. Today’s systems and tools do not support this, as computer systems typically support only a single user and computer-aided design tools require significant training. This paper presents the design of a new system to facilitate a collaborative 3D design process. First, we discuss a set of guidelines which have been introduced by others and that are relevant to collaborative 3D design systems. Then, we introduce the new system, which consists of two main parts. The first part is an easy-to-use conceptual 3D design tool that can be used productively even by naive users. The tool provides novel interaction techniques that support important properties of conceptual design. The user interface is non-obtrusive, easy-to-learn, and supports rapid creation and modification of 3D models. The second part is a novel infrastructure for collaborative work, which offers an interactive table and several large interactive displays in a semi-immersive setup. It is designed to support multiple users working together. This infrastructure also includes novel pointing devices that work both as a stylus and a remote pointing device. The combination of the (modified) design tool with the collaborative infrastructure forms a new platform for collaborative virtual 3D design. Then, we present an evaluation of the system against the guidelines for collaborative 3D design. Finally, we present results of a preliminary user study, which asked naive users to collaborate in a 3D design task on the new system.     

复杂参数产品形态设计中的解空间降维方法

针对产品形态设计中评价标准的模糊性问题,探索了智能化设计方法中的操作性技术.基于产品的形态编码,采用参数权重集中曲线的噪声度自动评测方式对解空间进行降维处理,并对产品形态编码分级.在降维后的系列解空间中使用交互式遗传算法搜索最优方案,并逐级完成形态的细化设计.文中方法从用户交互选择信息中提取出各参数对产品形态的重要性等级,作为细化设计过程的依据.求解过程全部基于解码的形态方案进行,为设计师的工作提供了直观的界面.     

Supporting the acquisition and modeling of requirements in software design

This paper describes a system for supporting the construction of software requirement models, which are initial computable models representing users' requirements in software design. The system principally consists of two components, a system for aiding the formation of requirement concepts by visualizing a user's thought space, and a knowledge-based system which automatically assembles the ascertained requirement concepts into a requirement model. The system extracts reusable components of a requirement model, corresponding to the users' abstract requirement concept, from a store of similar past cases. The components are then automatically arranged using heuristic reasoning. By using the system, users can make their requirement concepts more mature, and simultaneously get computable requirement models as by-products.     

Interactive evolutionary solution synthesis in fuzzy set-based preliminary engineering design

This paper describes an interactive evolutionary approach to synthesize component-based preliminary engineering design problems. This approach is intended to address preliminary engineering design as an evolutionary synthesis process, with the needs for human-computer interaction in a changing environment caused by uncertainty and imprecision inherent in the early design stages. It combines an agent-based hierarchical design representation, set-based design generation, fuzzy design trade-off strategy and interactive design adaptation into evolutionary synthesis to gradually refine and reduce the search space while maintaining solution diversity to accommodate future changes. The fitness function of solutions employed is not fixed but adapted according to elicited human value judgment and constraint change. It incorporates multi-criteria evaluation as well as constraint satisfaction. This new approach takes advantage of the different roles of computers and humans play in design and optimization. The methodology will be applicable to general multi-domain applications, with emphasis on physical modeling of dynamic systems. An automotive speedometer design case study is included to demonstrate the methodology.     

模型描述语言NUMDL的设计与实现

模型描述语言NUMDL是智能决策系统JSEIDSS的一个重要组成部分,它为系统模型的建立和管理提供了很好的工具。NUMDL语言功能强,描述概念和数学公式简明,易写易读,且有一定的特色,本文介绍它的设计与实现。     

A nonparametric approach to design robust controllers for uncertain systems: Application to an air flow heating system

This paper presents an approach to design robust fixed structure controllers for uncertain systems using a finite set of measurements in the frequency domain. In traditional control system design, usually, based on measurements, a model of the plant, which is only an approximation of the physical system, is first built, and then control approaches are used to design a controller based on the identified model. Errors associated with the identification process as well as the inevitable uncertainties associated with plant parameter variations, external disturbances, measurement noise, etc. are expected to all contribute to the degradation of the performance of such a scheme. In this paper, we propose a nonparametric method that uses frequency-domain data to directly design a robust controller, for a class of uncertainties, without the need for model identification. The proposed technique, which is based on interval analysis, allows us to take into account the plant uncertainties during the controller synthesis itself. The technique relies on computing the controller parameters for which the set of all possible frequency responses of the closed-loop system are included in the envelope of a desired frequency response. Such an inclusion problem can be solved using interval techniques. The main advantages of the proposed approach are: (1) the control design does not require any mathematical model, (2) the controller is robust with respect to plant uncertainties, and (3) the controller structure can be chosen a priori, which allows us to select low-order controllers. To illustrate the proposed method and demonstrate its efficacy, an application to an air flow heating system is presented.     

Developing a multi-objective genetic optimisation approach for an operational design of a manual mixed-model assembly line with walking workers

A walking worker assembly line (WWAL), in which each cross-trained worker travels along the line to carry out all required tasks, is an example of lean system, specifically designed to respond quickly and economically to the fluctuating nature of market demands. Because of the complexity of WWAL design problems, classical heuristic approaches are not capable of solving problematic design characteristic of WWAL of very large design space. This paper presents a new genetic approach to address the mixed model walking worker manual assembly line optimisation design problem with multiple objectives. The aim is to select a set of operational variables to perform to the required demand for two product models. The goal is to produce the required models at the lowest cost possible, whilst keeping within an ergonomically balanced operation. Genetic algorithms are developed to tackle this problem. This paper describes the fundamental structure of this approach, as well as the influence of the crossover probability, the mutation probability and the size of the population on the performance of the genetic algorithm. The paper also presents an application of a developed algorithm to the operational design problem of plastic electrical box assembly line.     

A form verification system for the conceptual design of complex mechanical systems

This paper presents a summary of research into the development and implementation of a domain-independent, computer-based model for the conceptual design of complex mechanical systems [1]. The creation of such a design model includes the integration of four major concepts: (1) the use of a graphical display for visualizing the conceptual design attributes: (2) the proper representation of the complex data and diverse knowledge reguired to design the system; (3) the integration of quality design methods into the conceptual design: (4) the modeling of the conceptual design process as a mapping between functions and forms. Using the design of an automobile as a case study, a design environment was created which consisted of a distributed problem-solving paradigm and a parametric graphical display. The requirements of the design problem with respect to data representation and design processing were evaluated and a process model was specified. The resulting vehicle design system consists of a tight integration between a blackboard system and a parametric design system. The completed system allows a designer to view graphical representations of the candidate conceptual designs that the blackhoard system generates.     

An approach to the emergent design theory and applications

An emergent approach for the design of artifacts (artificial systems) is proposed. First, the system design process is reformulated in the framework of set and mapping theory, and the design problem is defined as an inverse mapping from the set of specifications depending on the environment to the set of components and their connections. The inverse problem can be solved by the iteration of forward mapping. Next, the problem is classified from the viewpoint of the specifications and the environment. The concepts of evolution, adaptation, learning, and coordination can be related to classified problems. Emergent design procedure is defined in the framework of these concepts, in particular by taking evolutionary computing techniques into account. Two examples are shown: the first is a design of complex linear passive filters, and the other is a design of multilink moving robots. This work was presented, in part, at the Third International Symposium on Artificial Life and Robotics, Oita, Japan, January 19–21, 1998     

Computer-aided design for manufacturing process selection

This paper describes an expert system that helps designers select a manufacturing process in the early stage of product design. First, the paper focuses on net-shape manufacturing processes and identifies the major factors that affect the selection of an appropriate process. Examples of these factors include shape, production volume and material. A versatile methodology should consider all the factors simultaneously in assessing the suitability of the candidate processes. The proposed system uses the concept of design compatibility analysis to represent the suitability of candidate processes with respect to the given product specifications. The system uses this knowledge to eliminate incompatible candidates and rank the compatible set of processes. A prototype system called DFPS uses HyperCard and Prolog to implement the proposed methodology. DFPS also contains information related to each process.     

CAD系统设计中的形式化方法与功能命题

本文结合作者多年的研究实践，对CAD系统功能设计理论和方法进行研究，并在此基础上提出和建立CAD系统功能设计的数学模型，其中包括：(1)介绍需求分析的形式化描述和表示方法，建立需求空间结构；(2)提出复合功能、设计逻辑、功能与参数依赖及交互效率等新概念，并分别建构复合功能的构造和效率命题；(3)阐述这些理论和方法在自行开发的专业化系统中的应用。