• 한국CDE학회논문집
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• 제2권1호
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• pp.35-43
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• 1997

Concurrent Engineering is one of the methods which are used for the rapid product development. One of the important features in Concurrent Egineering is that the development process is to be parallel and the organization should be cross-functional. In order that the process be parallel and that the organization be cross-functional, an integrated information system such as PDM (Product Data Management) is required. Although the integrated data base is constructed, it could be meaningless if the application softwares were not inter-operable. This study shows an example of intergrated information system from three-dimensional product design to mold design and tooling for the development of Deflection Yoke(DY) which is one of the important parts of Cathode Ray Tube(CRT). A three-dimensional product design software, which is based on a commercial code, has been developed by ourselves. Selective Laser Sintering(SLS), which is one of the rapid prototyping techniques, has been used in this study. Mold design has been done by the three-dimensional way. A newly developed method of mold tooling, which is called Quick Die Manufacturing(QDM), has been introduced.

• 한국CDE학회논문집
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• 제21권2호
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• pp.122-129
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• 2016

4D printing is a method that manufactures a programmed transformable 3d printed components that can be transformed in a pre-designed environment. We propose a service-oriented web architecture for supporting 4D printing system. Service model is classified under four kinds of functions: design, sharing, application and production. We designed RESTful web APIs for these functions. Some preliminary designs about the web API architecture and data modeling is discussed.

• ETRI Journal
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• 제46권4호
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• pp.716-726
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• 2024

An ultrawide stopband lowpass filter is reported using three stepped impedance resonators with high selectivity. The filter extends the stopband frequency range and attenuation, and two quarter-wave open stubs and three circular ground slots are introduced. The lumped and distributed equivalent models are derived and analyzed. The corresponding results are validated experimentally in a fabricated prototype. The prototype lowpass filter has a 3 dB cutoff frequency (f_c) of 2.9 GHz, and the stopband is extended up to 35 GHz (12.07f_c), with an attenuation level better than 20 dB throughout. The passband-to-stopband transition (3 dB-20 dB) bandwidth is 0.18 GHz, and the roll-off factor is 135 dB/GHz at 30 dB. The insertion loss is 0.3 dB at 1.6 GHz. The normalized circuit size of the proposed filter with respect to the guided wavelength is 0.04.

• 한국정보전자통신기술학회논문지
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• 제5권2호
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• pp.61-67
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• 2012

본 논문에서는 동작영역(dynamic range)을 고려하여 주파수 변환부에 높은 변환이득(conversion gain)과 선형성을 확보하면서 동시에 동작영역을 넓히는 설계방법을 제안하였다. 슈퍼헤테로다인 방식의 RF Front-End단에 능동혼합기(active mixer)를 적용하였으며, GaAs소자를 사용하였다. 회로구성은 설계가 용이하고 회로형태가 단순한 장점이 있는 드레인 혼합기로 구성하였으며, 수동 혼합기와의 동작영역을 비교,분석하였다. 시뮬레이션 결과 약 2.4dB의 변환이득과 0.2dBm의 이득-압축점, 그리고 71.9dB의 동작 영역를 나타내었으며, 수동혼합기와 비교하였을 때, 약 6dB의 동작영역이 개선됨을 확인하였다. 측정결과로는 약 2dB의 변환이득과 -1.0dBm의 이득-압축점, 그리고 71.1dB의 동작영역을 확인하였다. 수동혼합기와 비교하였을 경우, 약 8dB의 동작영역이 개선됨을 확인할 수 있다.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.163-181
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• 1998

In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

• Journal of electromagnetic engineering and science
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• 제14권2호
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• pp.54-60
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• 2014

A systematic design for asymmetric coupled-section Marchand baluns is presented. Asymmetrically coupled transmission lines in multilayer configuration are exploited for constructing Marchand baluns. Design equations for characteristic impedance and electrical length of asymmetrical coupled transmission lines are derived for establishing a systematic design procedure. Novel Marchand balun based on these design equations is composed of two identical asymmetrical coupled transmission lines. However, contrary to the general conventional design approach where ranges for characteristic impedances of coupled lines are ambiguously capitalized, values for characteristic impedance and length are explicitly expressed. Our approach is fundamentally different from the design method using coupling coefficients where solution for coupling coefficient is inherently restricted. To verify the proposed method, one design example is performed for wideband Marchand balun in multilayer configuration, and is fabricated for verifying the design procedure proposed. Maintaining the return loss more than 10 dB, the bandwidth is measured from 0.43 to 1.0 GHz, where $S_{21}$ and $S_{31}$ show better than -4 dB. The measured phase and amplitude imbalances illustrate 0.5 dB and ${\pm}5^{\circ}$, respectively.

• 패션비즈니스
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• 제9권2호
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• pp.160-173
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• 2005

Fashion is hard to expect owing to the rapid change in accordance with consumer taste and environment, and has a tendency toward variety and individuality. Especially street fashion d 21st century is not being regarded as one of the subcultures but is playing an important role as a fountainhead d fashion trend. Therefore, Searching and analyzing street fashions helps us to understand the popular fashions d the next season and also it is important in understanding the consumer fashion sense and commercial area. So, we need to understand fashion styles quantitatively and qualitatively by providing visual data and dividing images. The purpose of this study is to design for street fashion on design analysis using web which can update quantitative and qualitative data. through the on site investigation d street fashion, and put the information onto a database.

• 산업공학
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• 제16권spc호
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• pp.138-143
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• 2003

In this paper, an automated design system for ball-joint parts based on 3-D solid modeler is developed. Parametric modeling and API provided by 3-D solid modeler is engaged to develope the system which consists of four main modules such as : 3-D part modeling, parts assembling, 2-D drafting, and database interfacing modules. The automated design system is implemented on a computer, and shows us that it shorten the design processing time which have taken over 5 hours to only few minutes.

• 대한전자공학회논문지TC
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• 제45권1호
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• pp.110-114
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• 2008

본 논문에서는 단일 FET를 이용하여 2.14GHz/5.2GHz 이중대역 고효율 Class F 전력증폭기를 설계 구현하였다. 전송선로를 이용하여 초기의 정합값을 적절히 이동시켜 하나의 능동소자로 2.14GHz/5.2GHz의 이중대역에서 동작되는 전력증폭기를 설계하였으며, 2.14GHz에서 32.65dBm의 출력과 11dB의 출력이득 36%의 전력효율을, 5.2GHz에서 7dB의 출력이득의 특성을 보였다. 고조파를 제어 회로를 설계하여 증폭기의 출력단에 추가 하여 Class F로 동작하는 이중대역 전력증폭기를 설계 하였다. 이중대역 Class F 전력증폭기는 2.14GHz에서 9.9dB의 출력이득과 30dBm의 출력, 55%의 전력효율을 가졌으며, 5.2GHz에서 11.7dB의 출력이득을 갖는 특성을 보였다. 고조파 제어 회로를 이용한 이중대역 Class F 전력증폭기가 전력효율을 향상시킴을 보였다.

• 한국의류산업학회지
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• 제24권5호
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• pp.505-518
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• 2022

3D printing technology, also known as additive manufacturing(AM), has not been actively used in the clothing industry despite its potential for economic, environmental, and labor efficiency. Therefore, this study aims to propose a new 3D printing method for the clothing industry, which will be more readily accessible. This roll-type printing method can print wide-sized patterns at once using a 3D modeling program and a FDM 3D printer and help overcome the limitations imposed by the size of the printer. Then, to demonstrate the practical application cases of this printing method, bags of three designs were developed. Prior to product development, a thickness test was performed for stable printing using TPU(Thermoplastic Poly Urethane) filament, and a thickness of 0.45 mm was found to be most suitable for it. Next, the time efficiency test showed that the roll-type printing method takes less time compared to the general printing method in printing wide-sized patterns. Based on these tests, three bags, , and , were developed to confirm the suitability of the roll-type printing method for product development. The advantages of 3D roll-type printing can lie in overcoming of the spatial limitation, and the environmental sustainability as it can reduce waste from the production process. This study is significant in that it presents a new 3D printing method to improve the space limitations and time inefficiency of 3D printers.