• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.647-653
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• 2005

According to the design concept of microwave front-end, a low noise amplifier block using HBT cascode topology is proposed to provide high gain and low noise figure with low bias current. We has implemented MMIC-LNA with a modified configuration using inductors to show low noise at the emitter and base of cascoded HBT-MMIC amplifier. The measured performance of the designed MMIC-LNA at 3.7GHz are a gain of 19dB, noise figure of 2.7dB and image rejection of 35dBc using a supply of 3mA and 2.7V. We can convinced that cascoded amplifier block to fulfill a high gain, low noise and image rejection if microwave front-end receiver is designed by cascode MMEC-LNA with the active image rejection filter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.919-925
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• 2011

In this paper, we designed and analyzed a 3D isotropic bulk structure consisting of thin wires and SRR's(Split Ring Resonator) with which the permittivity and permeability can be controlled at the same time. For the 3D isotropic bulk structure, first of all, the geometry seen by three main axes must look alike. Thus, we adopted the orthogonal thin wires and symmetrical SRR's. As a result, we constructed metamaterial bulk structures of which effective relative permittivity and permiability are about -0.6 and -1.5, respectively. Its refractive index is about -0.95 in each direction(x, y and z direction). The computed Brillouin dispersion diagram also showed that the proposed structure is almost near isotropic.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.277-283
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• 2016

Recently, the interests in three-dimensional design and BIM(Building Information Modeling) are increasing in civil engineering sector and the researches about three-dimensional design and quantity take-off methods for civil engineering structures have been conducted. However, these studies are just carried out the 3D design and quantity calculation of civil structures on the road or railway such as bridges and tunnels. The study on the quantity take-off methods and the evaluation of calculated results on the earth works should be performed in more detail. Based on these backgrounds in mind, the study was conducted the three-dimensional road design and evaluated the quantity take-off results on the earth works using 3D calculation method(average end area method, prismoidal method and composit method). The calculated quantity from composit method showed about 5% error of measuring efficiency than the average end area method, and when reporting the quantity calculation of earth works, it is necessary to specify the calculation method using quantity take-off of earth works.

• The Journal of the Acoustical Society of Korea
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• v.32 no.6
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• pp.502-508
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• 2013

In this paper, 2D array transducers using a conductive backer similar to 1-3 composites have been designed, fabricated, and evaluated. The conductive backer was based on well known manufacturing process of 1-3 composites with affordable ingredients. The 2D array transducer had 4,096 elements designed to have 3.5 MHz center frequency and a fractional bandwidth over 60 %. Fabricated prototype of the transducer satisfied the specifications in the center frequency and bandwidth. Performance over the entire elements was so uniform that the standard deviation was less than 0.81 dB. Thus applicability of the conductive backer proposed in this work to 2D array transducers was verified.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.41-44
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• 2006

본 연구에서 3차원 지형공간정보의 구축 및 처리, 가시화를 위하여 개인용 PC와 임베디드 단말기의 포켓 PC환경에서 자료 호환 및 동시 운영이 가능한 실시간 3차원 GIS의 Prototype의 설계 및 구현과 적용 실험을 하고자 한다 OpenGL(Open Graphic Library)과 OpenGL|ES (Embedded System)를 활용하여 도시경관을 구성하는 주요객체인 지형, 건물, 교통, 식생 등을 통합적으로 저작 및 3D 객체 모델링 및 렌더링이 통합 및 개별 운영 시스템을 설계하고 구현하였다. 구현 단계에서 개인용 PC 운영환경에서는 기능성 향상에 중점을 두어 공간 데이터베이스 설계, 텍스처 영상 매핑처리, 대용량의 3차원 공간정보 처리 및 관리, 가시화, 렌더링, 모델링 기능들을 제공하며, PDA 휴대용 단말운영환경을 지원하는 모바일 시스템에서는 실시간 모바일 저작기능과 렌더링 기능에 주안점을 두어 개발하였다. 한편 연구 결과로 구현된 시스템은 원도우 XP 기반의 개인용 PC와 PDA 단말기 상에서 3D 객체 자료구조가 호환되어 향후 다양한 응용이 가능할 것으로 생각된다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.166-167
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• 2010

최근 전기/전자 제품 개발에서 대용량, 소형화가 이루어지면서 제품 설계에 열유동 및 구조적 문제가 중요한 요소로 등장하였다. 열유동은 발열체와 공기의 흐름에 관련이 있기 때문에 시스템의 구조를 어떻게 설계 하느냐가 방열의 중요한 요소이다. 본 논문에서는 Ansys사(社)의 소프트웨어를 이용하여 연료전지용 PCS에 대한 열유동, 구조 및 강도 해석을 수행하였다. 3D설계는 CAD(Computer Aided Design) 소프트웨어인 Pro Engineer를 이용하였다. 설계된 3D 도면을 Ansys Multiphysics로 불러들여 구조 및 강도해석을 하였고 CFD(Computational Fluid Dynamics) 소프트웨어인 Icepak으로 열유동해석을 수행하였다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.1-9
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• 2010

As the process technology scales down, an interconnection has became a major performance constraint for multi-core processors. Recently, in order to mitigate the performance bottleneck of the interconnection for multi-core processors, a 3D integration technique has drawn quite attention. The 3D integrated multi-core processor has advantage for reducing global wire length, resulting in a performance improvement. However, it causes serious thermal problems due to increased power density. For this reason, to design efficient 3D multi-core processors, thermal-aware design techniques should be considered. In this paper, we analyze the temperature on the 3D multi-core processors in function unit level through various experiments. We also present temperature characteristics by varying application features, cooling characteristics, and frequency levels on 3D multi-core processors. According to our experimental results, following two rules should be obeyed for thermal-aware 3D processor design. First, to optimize the thermal profile of cores, the core with higher cooling efficiency should be clocked at a higher frequency. Second, to lower the temperature of cores, a workload with higher thermal impact should be assigned to the core with higher cooling efficiency.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.7-11
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• 2014

In this paper, we designed resistive MMIC mixer using $0.5{\mu}m$ p-HEMT process. This Mixer is designed to have a similar performance in -4 ~ 4 dBm local oscillator signal power level and to maintain a constant conversion loss and linear performance due to the variation of local signal. In order to have such characteristics, we designed new feedback circuit topology by using FET, and minimized performance change for LO signal power level variation, also obtain MMIC mixer characteristics which is able to apply in wideband. In the design result, When the LO signal power is -4 ~ 4 dBm, there was 6 dB conversion loss and it came up with the excellent result that IIP3 got over 30 dBm in 0.5 ~ 2.6GHz frequency band.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1164-1169
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• 2009

In this study, the bracket for car was designed in 3D using Cimatron Die Design, one of the automatic modules. To facilitate the stamping of the product, the layout of the strip was adjusted slightly. The blank layout of the double-width, 2-line, 2-pull out inner carrier was then optimized as a single arrangement. 3D design was completed in 11 processes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.143-148
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• 2008

This Study is about driving simulation after road design by 3D-GIS in digital elevation model from digital aerial photogrammetry. For designing roads efficiently it's very important to consider geographical features before design when analyze the view. Nevertheless, existing studies is mainly restricted in the mountainous, despite of using digital map or aerial photogrammetry and the study which used aerial photo in the area where the road designing is made really is not get executed. Therefore, this study will do 3D-road design and driving simulation by appling really road design data to topography, on the basis of digital elevation generated from aerial photogrammetry.