• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.676-679
• /
• 2001

A low-temperature cofired-ceramic (LTCC) multi-layer ceramic (MLC) band-pass filter (BPF) is presented, which has the benefits of low cost and small size. The BPF is designed for a IMT-2000 handset. The computer-aided design technology is also presented. The BPF with an attenuation pole at below the passband has been discussed and realized. The equivalent circuit of the BPF was established by transmission lines and lumped capacitors. The frequency characteristics of the LTCC-MLC BPF is well acceptable for IMT-2000 application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.1
• /
• pp.56-60
• /
• 2002

A low-temperature cofired-ceramic (LTCC) multi-layer ceramic (MLC) band-pass filter (BPF) is presented, which has the benefits of low cost and small size. The BPF is designed for an IMT-2000 handset. The computer-aided design technology is also presented. The BPF with an attenuation pole at below the passband has been discussed and realized. The equivalent circuit of the BPF was established by transmission lines and lumped capacitors. The frequency characteristics of the LTCC-MLC BPF is well acceptable for IMT-2000 application.

• Journal of Engineering Education Research
• /
• v.11 no.1
• /
• pp.85-100
• /
• 2008

The purpose of this study is development of 'F1 in Schools Program' for elementary school student and validation of the program. Fifteen students were originally chosen from the W elementary school in Cheongju, Chungcheogbuk-Do. The children were tested on their understanding of science and 'F1 in Schools Program'. After developing the 'F1 in Schools Program', it was used in the classroom to evaluate applicability and to examine the responses from students, parents and schools. The program consists of 60 classes and the time of each class is 40 minutes. This study was conducted for 10 days from January 22nd, 2007 to February 2nd, 2007. CAD(Computer Aided Design), CFD(Computation Fluid Dynamics), CAM(Computer Aided manufacturing) and CNC Machine were used in this study and proved to be good materials for students in that they increased the students' participation and imagination. However, the children's cognitive and creative abilities as well as manuals written in English hampered the process. Most students, parents, schools seemed to be satisfied with use of the program. However, the schools showed that there was not enough understanding of the program as a whole. The processes with which students build and inspect using the $CO_2$Model Car not only improves the processing of the model but also enhanced the students scientific understanding related to the car speed.

• The Journal of Korean Academy of Prosthodontics
• /
• v.56 no.1
• /
• pp.17-24
• /
• 2018

Lost wax technique of casting wax patterns has been used principally to make metal frameworks of removable partial dentures. Since the development of digital technology and CAD, metal frameworks can be built through digital surveying and framework designing. Many cases proved that resin patterns made by CAD printing method were well adapted to internal oral structure and final metal frameworks also showed good internal adaptation as well. The metal frameworks of a removable partial denture were made by both lost wax technique and CAD technique and were applied to a patient with severe alveolar bone loss. Using CAD data and fit checker, internal adaptation of both metal frameworks were evaluated by comparing the gap between surveyed crown and its structure. This study is to prove that metal frameworks by both techniques showed adaptation that can be applied in clinical field.

• Journal of the Korean Society of Industry Convergence
• /
• v.5 no.1
• /
• pp.11-19
• /
• 2002

This study described computer aided die design system for cold forging of non-axisymmetric parts such as gears and splines. To design the cold forging die, an integrated approach based on a rule-base system and commercial F. E. code were adopted. This system is implemented on the personal computer and its environment is a commercial CAD package named as Auto CAD. The system includes four modules. In the initial data input module, variables which are necessary to design of die are inputted by user and die material are selected from the database according to the variables. In the analysis and redesign module, stress distribution acting on the designed die is analyzed by commercial FEM code NISA II with elastic mode. If die failure predicted, the designed die would modified in four ways to prevent die failure in both states of stress free and pressurizing. The developed system provides useful date and powerful capabilities for die design of non-axisymmetric parts.

• IE interfaces
• /
• v.8 no.3
• /
• pp.213-220
• /
• 1995

공정설계는 설계와 가공에 대한 지식을 갖고 있는 사람이 부품설계 도면의 정보를 이용, 생산 현장에서 소재를 부품으로 가공하기 위하여 필요한 가공정보들을 수집, 검토하여 상세한 작업지시를 준비하는 일련의 활동이라고 할 수 있다. 따라서 공정설계는 제품을 경제적, 효율적으로 생산하는데 필요한 체계적인 결정방식이며, 설계와 가공사이의 정보흐름을 원활하게 하여 제조공정상의 교량역할을 하는 핵심적인 부분이므로, 본 논문에서는 첨단생산시스템을 구현하기 위한 차세대가공시스템의 소과제중 하나인 "지적공정계획기술" 과제에서 기존에 상용화된 CAD/CAM(Compu-ter Aided Design / Manufacturing)시스템을 이용하여 설계와 가공의 정보를 체계화하고 지식 베이스화하여 설계정보가 생산현장까지 이어질 수 있도록 개발중인 컴퓨터를 이용한 공정설계자동화시스템(CAPP : Computer Aided Process Planning)에 대하여 기술하고자 한다.

• Journal of Korean Institute of Industrial Engineers
• /
• v.12 no.2
• /
• pp.13-19
• /
• 1986

The purpose of this paper is to develop a 3-dimensional human model, an ergonomic CAD (Computer-Aided Design) system which would be very helphul in ergonomic design. An interactive program was developed, in which a user could change layout, body size, skin volume, and posture of the human model. As an example, effect of inclination of a steering wheel on visibility of a display panel was demonstrated. he result showed that ergonomic design can be aided by the 3-dimensional human model, and by the perspective graph by which design and evaluation process can be carried out more effectively.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.3
• /
• pp.329-335
• /
• 2011

The finite element method (FEM) has been used for various fields like mathematics and engineering. However, the FEM has a difficulty in describing the geometric shape exactly due to its property of piecewise linear discretization. Recently, however, a so-called isogeometric analysis method that uses the non-uniform rational B-spline(NURBS) basis function has been developed. The NURBS can be used to describe the geometry exactly and play a role of basis functions for the response analysis. Nevertheless, constructing the NURBS basis functions in analysis is as costly as a meshing process in the FEM. Since the isogeometric method shares geometric data with CAD, it is possible to intactly import the model data from commercial CAD tools. In this paper, we use the Rhinoceros 3D software to create CAD models and export in the form of STEP file. The information of knot vectors and control points in the NURBS is utilized in the isogeometric analysis. Through some numerical examples, the accuracy of isogeometric method is compared with that of FEM. Also, the efficiency of the isogeometric method that includes the CAD and CAE in a unified framework is verified.

• The Journal of Korean Academy of Prosthodontics
• /
• v.56 no.3
• /
• pp.250-257
• /
• 2018

Generally dentures are manufactured by conventional method, however the frequency of fabricating denture using digital method is increasing due to the recent development of digital technology in dentistry. The digital method of manufacturing denture is classified into two systems; 3D scan of the impression to arrange the artificial teeth on the CAD (Computer-aided design) and 3D printing to produce the resin-based complete denture, or 3D scan of the model to design of the framework using CAD, resin pattern formation by 3D printing and casting of metal framework of complete denture or removable partial denture. In this case report, electronic surveying and design the metal framework of the dentures were performed using CAD program, and plastic resin patterns fabricated by 3D printing were casted for upper full denture and lower removable partial denture. During follow-up periods, dentures using digital method have provided satisfactory results esthetically and functionally.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.6
• /
• pp.1743-1752
• /
• 1996

In this paper, a precision inspection technique using CAD/CAI integration is proposed for the parts having very thin and sharp 3 dimensional curve features. The technique begings with feature reconstruction of turbine blades which have 3 dimensional combined feometry, such as splines, and thin circles. The alifnment procedures consistsb of two phases-rough and fine phases : rough phase alignment is based on the conventional 6 point5s probing on the clear cut surfacef, and fine phase alignment is based on the intial measurement on the 3 dimensional curved parts using an lterative measurement feed-back least sequares technique for alignment. Forf the analysis of profile tolerance of parts, the actual measured points are obtained by finding the closet points on the CAD geometry by the developed subdivision technique and the Tschebycheff norm is applied based on iterative fashion, giving accurate profile tolerance value. The developed inspection technique is applied to practical procedures of blade manufacturing and demonstrated high performance.