• Korean Journal of Computational Design and Engineering
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• v.16 no.1
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• pp.21-30
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• 2011

Similarity assessment of a CAD model is one of important issues from the aspect of model re-using. In real practice, many new mechanical parts are designed by modifying existing ones. The reuse of part enables to save design time and efforts for the designers. Design time would be further reduced if there were an efficient way to search for existing similar designs. This paper proposes an efficient algorithm of similarity assessment for mechanical part model with design history embedded within the CAD model. Since it is possible to retrieve the design history and detailed-feature information using CAD API, we can obtain an accurate and reliable assessment result. For our purpose, our assessment algorithm can be divided by two: (1) we select suitable parts by comparing MSG (Model Signature Graph) extracted from a base feature of the required model; (2) detailed-features' similarities are assessed with their own attributes and reference structures. In addition, we also propose a indexing method for managing a model database in the last part of this article.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.816-825
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• 2006

This paper describes the development of a web-based interference verification system in the mold design process. Although several commercial CAD systems furnish interference verification functions, those systems are very expensive and inadequate to perform collaborative works over the Internet. In this paper, an efficient and precision hybrid interference verification algorithm for the web-based interference verification system over the distributed environment has been studied. The proposed system uses lightweight CAD files produced from the optimally transformed CAD data through ACIS kernel and InterOp. Collaborators related to the development of a new product are able to verify the interference verification over the Internet without commercial CAD systems. The system reduces production cost, errors and lead-time to the market. Validity of the developed system is confirmed through case studies.

• Journal of Ship and Ocean Technology
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• v.9 no.3
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• pp.33-42
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• 2005

As the networks connect the world, enterprises tend to move manufacturing activities into virtual spaces. Since different software applications use different data terminology, it becomes a problem to interoperate, interchange, and manage electronic data among heterogeneous systems. It is said that approximately one billion dollar has been being spent yearly in USA for product data exchange and interoperability. As commercial CAD systems have brought in the concept of design feature for the sake of interoperability, terminologies of design features need to be harmonized. In order to define design feature terminology for integration, knowledge about feature definitions of different CAD systems should be considered. STEP standard have attempted to solve this problem, but it defines only syntactic data representation so that semantic data integration is not possible. This paper proposes a methodology for integrating modeling features of CAD systems. We utilize the ontology concept to build a data model of design features which can be a semantic standard of feature definitions of CAD systems. Using feature ontology, we implement an integrated virtual database and a simple system which searches and edits design features in a semantic way.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.401-408
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• 2003

A CAD program for metal bellows diaphragm was developed in this study. This program was written in AutoLISP on the AutoCAD system with a personal computer. Basic design concept used in this program is composition of a convolution that is tangent to two lines and 5 circles from given design parameters(initial radius, inner and outer diameter, thickness, pitch, etc.). The effects of altering some design parameters on stress distribution and fatigue life of bellows were estimated using commercial FEM code, NISAII. As a result, the metal bellows diaphragm was successfully designed by the CAD program. It is used to model a bellows geometry in pre-processor of FEM code. The FEM result shows that stress is dependent on straight line length, bellows diameter with same span, and fatigue life is also affected by design parameters.

• Journal of the KSME
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• v.55 no.5
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• pp.34-37
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• 2015

이 글에서는 다양한 분야에 응용될 수 있는, 부품의 3D CAD 모델의 비교를 위한 방법들과 최근 동향에 대해 소개한다.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.138-145
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• 2009

Custom medical treatment is being widely adapted to lots of medical applications. A technology for 3D modeling is strongly required to fabricate medical implants for individual patient. Needs on true 3D CAD data of a patient is strongly required for tissue engineering and human body simulations. Medical imaging devices show human inner section and 3D volume rendering images of human organs. CT or MRI is one of the popular imaging devices for that use. However, those image data is not sufficient to use for medical fabrication or simulation. This paper mainly deals how to generate 3D geometry data from those medical images. A new image processing technology is introduced to reconstruct 3D geometry of a human body vacancy from the medical images. Then a surface geometry data is reconstructed by using Marching cube algorithm. Resulting CAD data is a custom 3D geometry data of human vacancy. This paper introduces a novel 3D reconstruction process and shows some typical examples with implemented software.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1506-1511
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• 2002

A computer aided expert system fur spur, helical, bevel and worm gears was newly developed by using AutoiCAD system and its AutoLISP computer language in the present study. Two methods are available for a designer to draw a gear. The first method needs the gear design parameters such as pressure, module, number of tooth, shaft angle, velocity, materials, etc. When the gear design parameters are inputted, a gear is drawn in AutoCAD system and maximum allowable power and shaft diameter are calculated additionally. The second method calculates all dimensions and gear design parameters to draw a gear when the information such as transmission, reduction ratio, nm, materials and pressure are inputted. The system includes four programs. Each program is composed of a data input module, a database module, a strength calculation module, a drawing module, a text module and a drawing edit module. In conclusion, the CAD system would be widely used in companies to find the geometric data and manufacturing course.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1187-1192
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• 2003

The computer is an important tool to design an engineering system and CAD systems are widely used for various design practice. To meet the market requirements, the old mass production system is being changed into the mass customization system. As for CAD systems, it is increasingly required to extend, automate, and customize a wide range of functionality. This article describes the state-of-the-art of the principal technologies for customizing CAD systems. And we have implemented an application that enables the parametric design by directly inputting numerical values of parameters for a CAD model. Based on this application, we have developed another system that makes it possible sharing of part family data between SolidEdge and Pro/Engineer. Through customization of CAD systems, it is possible to improve the product quality using external knowledge-based systems or to integrate with external system such as CAE tools. This paper can be a guide for engineering designers who want to customize CAD systems.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.95-104
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• 2019

PURPOSE. To evaluate the effect of surface treatments and repair materials on the shear bond strength and to measure the fracture toughness of CAD/CAM provisional restoration materials. MATERIALS AND METHODS. Four CAD/CAM (3D printing: Nextdent C&B and ZMD-1000B Temporary, CAD/CAM resin block: Yamahachi PMMA disk and Huge PMMA block) and four conventional (monometacrylate: Jet and Alike, dimetacrylate: Luxatemp and Protemp 4) materials were selected to fabricate disk-shaped specimens and divided into six groups according to surface treatment (n=10). CAD/CAM materials were repaired with Jet or Luxatemp, while conventional materials were repaired with their own materials. The shear bond strength was measured by using universal testing machine. Ten rectangular column-shaped specimens for each material were fabricated to measure the fracture toughness by single edge v notched beam technique. Statistical analysis was performed by one-way ANOVA. RESULTS. The highest shear bond strength of CAD/CAM materials was achieved by SiC paper + sandblasting. It was also accomplished when repairing 3D printing materials with Luxatemp, and repairing CAD/CAM resin blocks with Jet. Yamahachi PMMA disk showed the highest fracture toughness. Nextdent C&B showed the lowest fracture toughness value but no statistically significant difference from Alike and Luxatemp (P>.05). CONCLUSION. In order to successfully repair the CAD/CAM provisional restoration, mechanical surface treatment and appropriate repair material according to the CAD/CAM material type should be selected. The CAD/CAM provisional materials have proper mechanical properties for clinical use as compared to conventional materials.

• Journal of the Korea Fashion and Costume Design Association
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• v.24 no.4
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• pp.87-99
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• 2022

The purpose of this study is to develop machine embroidery textile designs for each technique that can be expressed using a single-headed computer embroidery sewing machine through a machine embroidery CAD system. For research, embroidery CAD utilized the Artistic digitizer, and the guillotine computer-mechanical magnetization machine used ELNA. The design concept was limited to portraits and relics of independence activists in six memorial halls built in Korea. The results of this study are as follows. First, it was found that the machine embroidery texture, which could only be produced by industries in the past, can be expand in the infinite creative embroidery design area by enabling the digitalization of motif images and the simulation of machine embroidery techniques through various layout options. Second, in the development of machine embroidery textures, it was found that the setting of the width, height, axis ratio, stitch, object, path, length, density, layer order, etc. in embroidery CAD is a very important part of determining the completeness of the embroidery results. Third, mechanical embroidery textile designs, which can be represented by single-head computer machine embroidery machine were able to show colorful embroidery results that differs from the original image by using seven main techniques and five deep technique alone or in combination, according to the designer's intention.