Showing papers on "Conceptual design published in 2000"

Evaluation of idea generation methods for conceptual design: Effectiveness metrics and design of experiments

Abstract: A wide range of formal methods have been devised and used for idea generation in conceptual design. Experimental evidence is needed to support claims regarding the effectiveness of these methods in promoting idea generation in engineering design. Towards that goal this paper presents a set of effectiveness metrics experimental methods, data collection and analysis techniques. Statistically based Design of Experiments (DOE) principles were used in developing the guidelines. Four classes of operating variables were considered to characterize the design problem and the environment. The effectiveness metrics proposed are based on outcome and consists of the quantity, quality, novelty, and variety of ideas generated. Two experimental approaches have been developed. In the Direct Method, the influence of the type of design problem and various parameters related to the procedure of an idea generation method is measured by using the method in its entirety. In the Indirect Method, each idea generation method is decomposed into key components and its overall effectiveness is predicted by experimentally studying the effectiveness of its components and their mutual interactions.

Alternatives: exploring information appliances through conceptual design proposals

Abstract: As a way of mapping a design space for a project on information appliances, we produced a workbook describing about twenty conceptual design proposals. On the one hand, they serve as suggestions that digital devices might embody values apart from those traditionally associated with functionality and usefulness. On the other, they are examples of research through design, balancing concreteness with openness to spur the imagination, and using multiplicity to allow the emergence of a new design space. Here we describe them both in terms of content and process, discussing first the values they address and then how they were crafted to encourage a broad discussion with our partners that could inform future stages of design.

Model-driven development of Web applications: the AutoWeb system

Abstract: This paper describes a methodology for the development of WWW applications and a tool environment specifically tailored for the methodology. The methodology and the development environment are based upon models and techniques already used in the hypermedia, information systems, and software engineering fields, adapted and blended in an original mix. The foundation of the proposal is the conceptual design of WWW applications, using HDM-lite, a notation for the specification of structure, navigation, and presentation semantics. The conceptual schema is then translated into a “traditional” database schema, which describes both the organization of the content and the desired navigation and presentation features. The WWW pages can therefore be dynamically generated from the database content, following the navigation requests of the user. A CASE environment, called Autoweb System, offers a set of software tools, which assist the design and the execution of a WWW application, in all its different aspects, Real-life experiences of the use of the methodology and of the AutoWeb System in both the industrial and academic context are reported.

A feature-based approach towards an integrated product model including conceptual design information

Abstract: Due to the highly complex and informal data that has to be managed in the conceptual design this early design phase still lacks of suitable computer support. Furthermore, existing approaches towards a computer aided conceptual design are insufficiently integrated with the downstream applications of the product development process. The paper therefore introduces an approach towards a feature-based integrated product model that incorporates a feature-based representation scheme for capturing product semantics handled in the conceptual design phase and links early design with part and assembly modelling.

Managing digital libraries for computer-aided design

Abstract: This paper describes our initial efforts to deploy a digital library to support computer-aided collaborative design. At present, this experimental testbed, The Engineering Design Knowledge Repository, is an effort to collect and archive public domain engineering data for use by researchers and engineering professionals. We envision this effort expanding to facilitate collaboration and process archival for distributed design and manufacturing teams. CAD knowledge-bases are vital to engineers, who search through vast amounts of corporate legacy data and navigate on-line catalogs to retrieve precisely the right components for assembly into new products. This research attempts to begin addressing the critical need for improved computational methods for reasoning about complex geometric and engineering information. In particular, we focus on archival and reuse of design and manufacturing data for mechatronic systems. This paper presents a description of the research problems, an overview of the initial architecture of the testbed and a description of some of our preliminary results on conceptual design and design retrieval.

Multiobjective Satisfaction within an Interactive Evolutionary Design Environment

Abstract: The paper introduces the concept of an Interactive Evolutionary Design System (IEDS) that supports the engineering designer during the conceptual/preliminary stages of the design process. Requirement during these early stages relates primarily to design search and exploration across a poorly defined space as the designer's knowledge base concerning the problem area develops. Multiobjective satisfaction plays a major role, and objectives are likely to be ill-defined and their relative importance uncertain. Interactive evolutionary search and exploration provides information to the design team that contributes directly to their overall understanding of the problem domain in terms of relevant objectives, constraints, and variable ranges. This paper describes the development of certain elements within an interactive evolutionary conceptual design environment that allows off-line processing of such information leading to a redefinition of the design space. Such redefinition may refer to the inclusion or removal of objectives, changes concerning their relative importance, or the reduction of variable ranges as a better understanding of objective sensitivity is established. The emphasis, therefore, moves from a multiobjective optimization over a preset number of generations to a relatively continuous interactive evolutionary search that results in the optimal definition of both the variable and objective space relating to the design problem at hand. The paper describes those elements of the IEDS relating to such multiobjective information gathering and subsequent design space redefinition.

Conceptual design of the SPL II : A high-power superconducting $H^-$ linac at CERN

Abstract: An analysis of the revised physics needs and recent progress in the technology of superconducting RF cavities have led to major changes in the specification and in the design for a Superconducting Proton Linac (SPL) at CERN. Compared with the first conceptual design report (CERN 2000–012) the beam energy is almost doubled (3.5 GeV instead of 2.2 GeV), while the length of the linac is reduced by 40% and the repetition rate is reduced to 50 Hz. The basic beam power is at a level of 4–5 MW and the approach chosen offers enough margins for upgrades. With this high beam power, the SPL can be the proton driver for an ISOL-type radioactive ion beam facility of the next generation (‘EURISOL’), and for a neutrino facility based on superbeam C beta-beam or on muon decay in a storage ring (‘neutrino factory’). The SPL can also replace the Linac2 and PS Booster in the low-energy part of the CERN proton accelerator complex, improving significantly the beam performance in terms of brightness and intensity for the benefit of all users including the LHC and its luminosity upgrade. Decommissioned LEP klystrons and RF equipment are used to provide RF power at a frequency of 352.2 MHz in the lowenergy part of the accelerator. Beyond 90 MeV, the RF frequency is doubled to take advantage of more compact normal-conducting accelerating structures up to an energy of 180 MeV. From there, state-ofthe-art, high-gradient, bulk-niobium superconducting cavities accelerate the beam up to its final energy of 3.5 GeV. The overall design approach is presented, together with the progress that has been achieved since the publication of the first conceptual design report.

Conceptual design: issues and challenges

Abstract: Decisions made during conceptual design have significant influence on the cost, performance, reliability, safety and environmental impact of a product. It has been estimated that design decisions account for more than 75% of final product costs. It is, therefore, vital that designers have access to the right tools to support such design activities. In the early 1980s, researchers began to realize the impact of design decisions on downstream activities. As a result, different methodologies such as design for assembly, design for manufacturing and concurrent engineering, have been proposed. Software tools that implement these methodologies have also been developed. However, most of these tools are only applicable in the detailed design phase. Yet, even the highest standard of detailed design cannot compensate for a poor design concept formulated at the conceptual design phase. In spite of this, few CAD tools have been developed to support conceptual design activities. This is because knowledge of the design requirements and constraints during this early phase of a product's life cycle is usually imprecise and incomplete, making it difficult to utilize computer-based systems or prototypes. However, recent advances in fields such as fuzzy logic, computational geometry, constraints programming and so on have now made it possible for researchers to tackle some of the challenging issues in dealing with conceptual design activities. In this special issue, we have gathered together discussions on various aspects of conceptual design phase: from the capturing of the designer's intent, to modelling design constraints and solving them in an efficient manner, to verifying the correctness of the design.

Design candidate identification using neural network-based fuzzy reasoning

Abstract: Conceptual design has profound impact on success of a product design. Identification of the best conceptual design candidate is a crucial step as design information is not complete and design knowledge is minimal at conceptual design stage. This paper presents a method for design candidate evaluation and identification using neural network-based fuzzy reasoning. The method consists of the following steps: (1) acquisition of customer needs and ranking of their importance, (2) establishment of measurable metrics and their relations with customer needs, (3) development of design specifications and initial evaluation of design candidates, and (4) evaluation and identification of design candidates based on design specifications and customer needs using neural network-based fuzzy reasoning. A case study is given to show the effectiveness of the proposed method and associated algorithms.

Conceptual design and analysis by sketching

Abstract: The ability of a CAD system to perceive a three-dimensional model depicted in a single freehand sketch presents the practical possibility of bringing numerous established analysis tools into the early stages of design to institute conceptual analysis In this article we hypothesize that the key to enabling systems to reason and communicate about conceptual design is the language of sketching We explore this approach, outline the basic algorithms required, and provide several examples of an implemented system

Separating topology and geometry in space planning

Abstract: We are dealing with the problem of space layout planning here. We present an architectural conceptual CAD approach. Starting with design specifications in terms of constraints over spaces, a specific enumeration heuristics leads to a complete set of consistent conceptual design solutions named topological solutions. These topological solutions which do not presume any precise definitive dimension correspond to the sketching step that an architect carries out from the Design specifications on a preliminary design phase in architecture.

A Representation for Conceptual Design of Buildings

Abstract: The building representation for storing design solutions adopted in SEED-Config consists of two levels of abstraction models defined on top of the object-oriented data model The first level is an information model, called the building entity and technology model, which stores design data as they are generated during conceptual design, supports case-based reasoning, and shares data among all design participants This model represents each building entity as a generic container that encompasses its properties, taxonomy, geometry, composition, relationships, and design knowledge applied in generating it The second level is a conceptual model that defines the types of objects, relationships, and data needed to fully represent the information in a given design domain The conceptual model specifies the semantics of the design information for the domain using the syntax defined in the information model The proposed representation also includes a faceted classification scheme to define the controlled vocabula

Automatically generating OLAP schemata from conceptual graphical models

Abstract: tool specific schemata and configuration information for OLAP database tools from conceptual graphical models is an important prerequisite for a comprehensive tool support for computer aided data warehouse engineering (CAWE). This paper describes the design and implementation of such a generation component in the context of our BabelFish data warehouse design tool environment. It identifies the principal issues that are involved in the design and implementation of such a component and discusses possible solutions. The paper lists typical mismatches between the data model of commercial OLAP tools and conceptual graphical modeling notations, and proposes methods to overcome these expressive differences during the generation process. Further topics are the use of graph grammars for specifying and parsing graphical MD schema descriptions and the integration of the generation process into a metadata centered modeling tool environment.

Conceptual engineering of plasma-focus thermonuclear pulsors

Abstract: The basic engineering criteria for conceptual design of plasma focus devices is derived from a thermonuclear model, and applied successfully to the operation of small neutron pulsors. The theory is able to explain the variation of the neutron yield with the gas pressure in deuterium-filled chambers, the current evolution, and the electrode geometrical parameters. The performance of a prototype designed to optimize the flux/fluence ratio is presented, contrasting the experimental outcomes with the model. A set of effective design parameters is deduced, which ensure a band confidence of 20%.

Aircraft conceptual design using genetic algorithms

Abstract: Nomenclature Aircraft design is a complex multidisciplinary process to determine aircraft configuration variables that satisfy a set of mission requirements. It is very hard for aircraft designers to foresee the consequences of changing certain variables. Furthermore, conventional optimization processes are limited by the type and number of parameters used, resulting in sub-optimal designs. The objective of this research is to test the functionality and implementation of a multidisciplinary aircraft conceptual design optimization method using an adaptive genetic algorithm (GA), as a feasible alternative to the existing sizing and optimization methods. To illustrate the approach the algorithm is used to optimize a medium range commercial aircraft, with takeoff weight as an optimization goal, subjected to constraints in performance and geometric parameters. Adaptive and traditional formulations for the handling of constraints by the GA are tested and compared. Results show the ability of the adaptive GA to unbiased search through the design space of aircraft conceptual designs, leading to more viable aircraft configurations than the traditional GA approach at reduced timeframes, with a lower cost than current aircraft design optimization procedures.

Towards the support of innovative conceptual design through interactive designer/evolutionary computing strategies

Abstract: The paper discusses the requirements of the engineering designer during the higher, conceptual levels of the design process in terms of search within initial predefined design spaces and subsequent exploration of transformed design spaces. Such transformation is based upon information gathered from initial search using evolutionary techniques that rapidly identify high-performance regions of complex design spaces. It is proposed that off-line processing of such information and associated design team discussion in an iterative designer/evolutionary search procedure can strengthen the knowledge base relating to the problem at hand and initiate significant change in the design environment. Research relating to appropriate evolutionary search and exploratory procedures is described and illustrated with results from simple test functions and real-world design problems. These results support discussion related to the manner in which the techniques may best support innovative and creative design activity in an interactive design team/evolutionary search environment.

A graph-theoretic approach to conceptual design with functional perspectives

Abstract: This paper explores the concepts of concurrency in design and develops an approach that involves reliability and other functional perspectives at the conceptual design stage. The paper uses graph theory to represent a product and define the relationships between its components. It employs the graph-theory concepts of the “tree” and the “forest” to represent a functional design artefact and idle condition, respectively. The approach presented in the paper provides a more refined visualisation of the energy flow and is applicable to numerous designs including sliding gears, clutches, overrunning clutches and flywheels, amongst others. It can be used to concurrently modify the design taking into consideration various constraints, e.g. expected mechanical failures and cost considerations. A case study is presented to illustrate the benefits of the approach discussed in the paper.

Artificial Intelligence in Design `00

Abstract: Preface. Part 1: Design Theory. Designing a font to test a theory T. Smithers. The role of multicriteria problem solving in design L. Mandow, J.L.P. De La Cruz. Limited computation, unlimited design J.-P. Protzen, et al. Part 2: Knowledge Modeling. Towards an ontological framework for knowledge-based design systems F. Varejao, et al. Knowledge modeling in design - the MOKA framework R. Klein. Expressing regulatory design knowledge for critiquing intelligent design assistants M. Ursu, P. Hammond. Part 3: Knowledge Management for Design. Towards a systematic repository of knowledge about managing collaborative design conflicts M. Klein. Managing knowledge in dispersed design companies facilitating context-driven design support through multiple perspectives P.A. Rodgers, et al. An integrated development environment for the design and maintenance of large configuration knowledge bases A. Felfernig, et al. Part 4: Shapes in Design. Shape grammer-based expert systems for engineering design M. Agarwal, J. Cagan. Categorisation of shapes using shape features S.-H. Park, J.S. Gero. Representations from generative systems A. Koutamanis. Part 5: Evolutionary Systems in Design. Interactive evolutionary conceptual design systems I. Parmee, et al. Fully automated design and manufacture of real machines H. Lipson, J.B. Pollack. Evolutionary structured planning C. Bezerra, C.L. Owen. Part 6: Process-Based Reasoning in Design. Structural engineering support through constraint satisfaction E. Gelle, et al. Signposting for design process improvement J. Clarkson, et al. Building design support by soft computing O.Ciftcioglu, et al. Part 7: Case-Based Reasoning in Design. Design case retrieval by generioc representations H.H. Achten. Characterising evolutionary design case adaption A. Gomez de Silva Garza, M.L. Maher. Exposures to examples A. Heylighen, I.M. Verstunen. Part 8: Learning in Design. Design heuristics extraction P. Matthews, et al. Evaluating a model of learning in design using protocol analysis S.K. Sim, A.H.B. Duffy. Discovery of design methodologies C. Shakeri, et al. Part 9: Exploration and Generation in Design. A framework for concept generation and exploration Y.-C. Liu, et al. Erasure in design space exploration R. Woodbury, et al. A design representation to support automated design generation J. Heisserman, et al. Part 10: Context in Design. Reminding and context in design C. Charlton, K. Wallace. Computational situated learning in design R. Reffat, J.S. Gero. Reasoning with design rationale J. Burge, D.C. Brown. Part 11: Agent-Based Design Systems. Deliberate evolution in multi-agent systems F.M.T. Brazier, et al. Expectation formation in multi-agent systems D.L. Grecu, D.C. Brown. Development of an intelligent agent for the design of local area networks H. Rezazad, G. Tecuci. Meaning mediated mechanism: A prototype for constructing and negotiating meaning in collaborative design J. Haymaker, et al. Contact Author Electronic Addresses. Author Index.

A Conceptual Design of A Departure Planner Decision Aid

Abstract: Terminal area Air Traffic Management handles both arriving and departing traffic. To date, research work on terminal area operations has focused primarily on the arrival flow and typically departures are taken into account only in an approximate (average) manner. However, arrivals and departures are highly coupled processes especially in the terminal airspace, with complex interactions and sharing of the same airport resources between arrivals and departures taking place in practically every important terminal area. Therefore, the addition of automation aids for departures, possibly in co-operation with existing arrival flow automation systems, could have a profound contribution in enhancing the overall efficiency of airport operations. This paper presents the conceptual system architecture for such an automation aid, the Departure Planner (DP). This architecture can be used as a core in the development of decision -aiding systems to assist air traffic controllers in improving the performance of departure operations and optimize runway time allocation among different operations at major congested airports. The design of such systems is expected to increase the overall efficiency of terminal area operations and yield benefits for all stakeholders involved in Air Traffic Management (ATM) operations, users as well as service providers.

Development of a Computer Code, ONCESG, for the Thermal-Hydraulic Design of a Once-Through Steam Generator

Abstract: Development of the conceptual design of a 300 MWt integral reactor, SMART (System-integrated Modular Advanced ReacTor), for utilization in nuclear cogeneration plants has been completed at the Korea Atomic Energy Research Institute (KAERI). The major primary components of the SMART such as modular helical steam generators, main circulation pumps and a self regulating pressurizer are integrated into a reactor vessel. It is a common practice to employ a once-through steam generator in integral reactor designs because of its advantages in compactness and simplicity of the flow path arrangements. In this study, a thermal hydraulic design and performance analysis computer code for a once-through steam generator using helically coiled tubes, ONCESG, is developed. To benchmark the developed physical models and computer code, once-through steam generators developed by other designers are simulated and ONCESG calculated results are compared with the design data. The overall characteristics of heat transfer area, p...

Information Modeling of Conceptual Process Planning Integrated With Conceptual Design

Abstract: Conceptual process planning is a key activity for designers to evaluate manufacturability and manufacturing cost and time in the early product development stage. Since major manufacturing cost is determined in early design, it is critical to be able to assess manufacturability and cost as early as possible in the design process. The integration between process planning and design is critical to enable these analyses. A literature review of the current status of Computer-Aided Design (CAD) and Computer-Aided Process Planning (CAPP) software technologies reveals the lack of interface standards to enable the integration of these systems. In order to develop interface standards, information models have to be first developed to define the interfaces. An initial information model for conceptual process planning has been developed. This model includes an activity model and an object model for manufacturing process selection, resource selection, and cost and time estimation. The activity model sets the context in which the objects are used for information sharing and exchange. The object model defines classes used in conceptual process planning. The main purpose of developing this model is to initiate the development of standard interface specifications that are necessary for design and process planning integration.

Robust concept exploration of propulsion systems with enhanced model approximation capabilities

Abstract: Improvements in industrial productivity require the creation of a reliable design in the shortest possible time. This is especially significant for designs thai involve computer intensive analyses. The Robust Concept Exploration Method (RCEM) embodies a systematic approach to configuring complex engineering systems in the early stages of product design by introducing quality considerations based on the robust design principle. Approximation techniques are employed in the RCEM to replace intensive analysis programs for saving computational time and cost, thereby increasing the efficiency of the design process. In this paper, the applicability of the RCEM for multiobjective complex systems design is examined by applying it to the propulsion system conceptual design process at Pratt and Whitney. Various approximation techniques are studied and a new strategy is proposed to enhance the existing model approximation techniques embodied in the RCEM.

Distributed multi-reasoning mechanism to support conceptual structural design

Abstract: The conceptual phase of structural design involves selecting preliminary materials, selecting the overall structural form of the building, producing a rough dimensional layout, and considering technological possibilities. Decisions are made on the basis of such information as height of the building, building use, typical live load, wind velocity, earthquake loading, design fundamental period, design acceleration, maximum lateral deflection, spans, story height, and other client requirements. More detailed information about the task itself, constraints, possible solution principles, and known solutions for similar problems is extremely useful in the process of defining and finding a solution to the design problem. This paper presents the M-RAM, which is intended to assist engineers in the conceptual phase of the structural design of tall buildings by providing designers with adapted past design solutions generated by a distributed multi-reasoning mechanism. The objective of the M-RAM (Multi-Reasoning Model...

Evolving structural design solutions using an implicit redundant Genetic Algorithm

Abstract: Performing synthesis during conceptual design provides substantial cost savings by selecting an efficient design topology and geometry, in addition to selecting the structural member properties. A new evolutionary-based representation, which combines redundancy and implicit fitness constraints, is introduced to represent and search for design solutions in an unstructured, multi-objective structural frame problem. The implicit redundant representation genetic algorithm, in tandem with the unstructured problem domain definition, allows the evaluation of diverse frame topologies and geometries. The IRR GA allows the representation of a variable number of location independent parameters, which overcomes the fixed parameter limitations of standard GAs. The novel frame designs evolved by the IRR GA synthesis design method compare favourably with traditional frame design solutions calculated by trial and error.

Collaborative optimization with disciplinary conceptual design

Abstract: For the first time, a multilevel optimization approach with disciplinary conceptual design is demonstrated. Collaborative optimization is used to decompose an example bridge design problem among two groups of designers --- a superstructure design group and a deck design group. The disciplinary groups are allowed to search over different design concepts and formulate the design variables and constraints for each. The autonomy of the two groups is managed by a system-level group which insures that overall system objectives are met and coupling is properly accounted for. Even though discrete conceptual design occurs within the disciplinary groups, a continuous gradient-based optimization algorithm is used at the system level. The procedure was started from a nonoptimal concept, and converged to the optimal concept.