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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Journal of Computational Design and Engineering
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Journal DOI :
Society of CAD/CAM Engineers
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Volume & Issues
Volume 8, Issue 4 - Dec 2003
Volume 8, Issue 3 - Sep 2003
Volume 8, Issue 2 - Jun 2003
Volume 8, Issue 1 - Mar 2003
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CPC Framework for Sharing Product Information Across Enterprises
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 201~211
Collaborative product commerce (CPC) is a newly emerging technology to support inter-enterprise collaboration through the product life-cycle. From the IT point of view, CPC is software technology to integrate product, process and resources of different enterprises using Web technologies. In this paper, we introduce a CPC framework for integrating product information across enterprises, which being developed as a part of the CPC project by ETRI. The product metadata represented by XML schema, which is compatible with ISO STEP PDM Schema standard, is presented to semantically and schematically integrate distributed product information. The web services technologies are discussed to support the interoperability of application systems related to the product development, such as CAD and PDM, where most of these applications run in a distributed environment. Finally, we implement the frame-work to integrate distributed product information.
Development of Algorithms for Accuracy Improvement in Transfer-Type Variable Lamination Manufacturing Process using Expandable Polystrene Foam
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 212~221
In order to reduce the lead-time and cost, the technology of rapid prototyping (RP) has been widely used. A new rapid prototyping process, transfer-type variable lamination manufacturing process by using expandable polystyrene foam (VLM-ST), has been developed to reduce building time, apparatus cost and additional post-processing. At the same time, VLM Slicer, the CAD/CAM software for VLM-ST has been developed. In this study, algorithms for accuracy improvement of VLM-ST, which include offset and overrun of a cutting path and generation of a reference shape are developed. Offset algorithm improves cutting accuracy, overrun algorithm enables the VLM-ST process to make a shape of sharp edge and reference shape generation algorithm adds additional shape which makes off-line lamination easier. In addition, proposed algorithms are applied to practical CAD models for verification.
U sing Artificial Intelligence in the Configuration Design of a High-Speed Train
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 222~230
Artificial intelligence has been used in the configuration design stage of high-speed train. The traction system of a high-speed train is composed of transformers, motor blocks, and traction motors of which locations and number in the trainset should be determined in the early stage of the train conceptual design. Components of the traction system are heavy parts in the train, so it gives strong influence to the top speeds and overall train configuration of high-speed trains. Top speeds have been predicted using the neural network with the associated data of the traction system. The neural networks have been learned with data sets of many commercially operated high-speed trains, and the predicted results have been compared with the actual values. The configuration design of the train set of a high-speed train determines the basic specification of the train and layout of the traction system. The neural networks is a useful design tool when there is not sufficient data for the configuration design and we need to use the existing data of other train for the prediction of trainset in development.
Data Server Oriented Computing Infrastructure for Process Integration and Multidisciplinary Design Optimization
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 231~242
Multidisciplinary Design Optimization (MDO) is an optimization technique considering simultaneously multiple disciplines such as dynamics, mechanics, structural analysis, thermal and fluid analysis and electromagnetic analysis. A software system enabling multidisciplinary design optimization is called MDO framework. An MDO framework provides an integrated and automated design environment that increases product quality and reliability, and decreases design cycle time and cost. The MDO framework also works as a common collaborative workspace for design experts on multiple disciplines. In this paper, we present the architecture for an MDO framework along with the requirement analysis for the framework. The requirement analysis has been performed through interviews of design experts in industry and thus we claim that it reflects the real needs in industry. The requirements include integrated design environment, friendly user interface, highly extensible open architecture, distributed design environment, application program interface, and efficient data management to handle massive design data. The resultant MDO framework is datasever-oriented and designed around a centralized data server for extensible and effective data exchange in a distributed design environment among multiple design tools and software.
Efficient Computation and Control of Geometric Shape Morphing based on Direction Map
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 243~253
This paper presents a new geometric morphing algorithm for polygons based on a simple geometric structure called direction map, which is mainly composed of a circular list of direction vectors defined by two neighboring vertices of a polygon. To generate a sequence of intermediate morphing shapes, first we merge direction maps of given control shapes based on a certain ordering rule of direction vectors, and scale the length of each direction vectors using Bezier or blossom controls. We show that the proposed algorithm is an improvement of the previous methods based on Minkowski sum (or convolution) in th aspects of computational efficiency and geometric properties.
Estimation of Sculptured Surface NC Machining Time
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 254~261
In mold and die shops, NC machining process mainly affects the quality of the machined surface and the manufacturing time of molds and dies. The estimation of NC machining time is a prerequisite to measure the machining productivity and to generate a process schedule, which generally includes the process sequence and the completion time of each process. It is required to take into account dynamic characteristics in the estimation, such as the ac/deceleration of NC machine controllers. Intensive observations at start and end points of NC blocks show that a minimum feedrate, a key variable in a machining time model, has a close relation to a block distance, an angle between blocks, and a command feedrate. Thus, this study addresses regression models for the minimum feedrate estimation on short and long NC blocks considering these parameters. Furthermore, machining time estimation models by the four types of feedrate behaviors are suggested based on the estimated minimum feedrate. To show the validity of the proposed machining time model, the study compares the estimated with the actual machining time in the sculptured surface machining of several mold dies.
Computation of Section Curves, Reflection Characteristic Lines, and Asymptotic Curves for Visualization
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 262~269
An approach to compute characteristic curves such as section curves, reflection characteristic lines, and asymptotic curves on a surface is introduced. Each problem is formulated as a surface-plane inter-section problem. A single-valued function that represents the characteristics of a problem constructs a property surface on parametric space. Using a contouring algorithm, the property surface is intersected with a horizontal plane. The solution of the intersection yields a series of points which are mapped into object space to become characteristic curves. The approach proposed in this paper eliminates the use of traditional searching methods or non-linear differential equation solvers. Since the contouring algorithm has been known to be very robust and rapid, most of the problems are solved efficiently in realtime for the purpose of visualization. This approach can be extended to any geometric problem, if used with an appropriate formulation.
Automatic Quadrilateral Element Mesh Generation Using Boundary Normal Offsetting In Various Two Dimensional Objects
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 270~277
In two dimensional mechanical design analysis, quadrilateral element mesh is preferred because it provides more accurate result than triangular element mesh. However, automation of quadrilateral element mesh generation is much more complex because of its geometrical complexities. In this study, an automatic quadrilateral element mesh generation algorithm based on the boundary normal offsetting method and the boundary decomposition method is developed. In so doing, nodes are automatically placed using the boundary normal offsetting method and the decomposition method is applied to decompose the designed domain into a set of convex subdomains. The generated elements are improved by relocation of the existing nodes based on the four criteria - uniformity, aspect ratio, skewness and taper degree. The developed algorithm requires minimal user inputs such as boundary data and the distance between nodes.
Calculation of Intersection between Z-map Vectors and Circularly Moving Filleted-end Mills
Korean Journal of Computational Design and Engineering, volume 8, issue 4, 2003, Pages 278~288
Presented in this paper is a numerical method for calculating the intersection points between Z-map vectors and the tool swept surface for circularly moving filleted-end mills. In numerically controlled(NC) machining simulation for large moulds and dies, a workpiece is frequently approximated as a set of z-axis aligned vectors, called Z-map vectors, and then the machining processes can be simulated through updating the Z-map with the intersection points. Circular motions are typically used for machining the free-form surfaces. For fast computation, we express each of intersection points with a single-variable non-linear equation and calculate the candidate interval in which the unique solution exists. Then, we prove the existence of a solution and its uniqueness in this candidate interval. Based on these properties, we can effectively apply numerical methods to finally calculate the solution of the nonlinear equation within a given precision. Experimental results are given for the case of a TV monitor and the hood of a car.