• Journal of electromagnetic engineering and science
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• 제16권3호
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• pp.164-168
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• 2016

A dual-band through-the-wall imaging radar receiver for a frequency-modulated continuous-wave radar system was designed and fabricated. The operating frequency bands of the receiver are S-band (2-4 GHz) and X-band (8-12 GHz). If the target is behind a wall, wall-reflected waves are rejected by a reconfigurable $G_m-C$ high-pass filter. The filter is designed using a high-order admittance synthesis method, and consists of transconductor circuits and capacitors. The cutoff frequency of the filter can be tuned by changing the reference current. The receiver system is fabricated on a printed circuit board using commercial devices. Measurements show 44.3 dB gain and 3.7 dB noise figure for the S-band input, and 58 dB gain and 3.02 dB noise figure for the X-band input. The cutoff frequency of the filter can be tuned from 0.7 MHz to 2.4 MHz.

• 한국통신학회논문지
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• 제40권9호
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• pp.1819-1827
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• 2015

저밀도 지선 구간의 운영 효율성 향상을 위한 ICT기반 차상중심 열차제어시스템이 제안되었다. 이와 더불어 기존 열차집중제어노선과 연계하는 새로운 ICT기반 지역제어센터 개발 또한 필요하다. 이러한 개발 시스템의 정량적 목표를 만족하기 위해서는 RAMS 활동이 요구된다. 본 논문에서는 예비위험원 분석을 통하여 위험원과 위험원 기여 인자를 도출하고, 위험도가 허용할 수 있는 수준으로 제어되도록 안전대책을 수립하였다.

• 한국지능시스템학회논문지
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• 제25권3호
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• pp.260-265
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• 2015

본 논문은 에지 특징을 이용한 얼라인 시스템을 제안한다. 얼라인 시스템은 PCB나 LCD 패널 등에 새겨진 기준 마크(fiducial mark)를 통하여 위치 정보를 획득한다. 그러므로 획득한 영상에서 정확하게 기준 마크를 찾는 것이 얼라인 시스템 성능의 지표가 된다. 에지 특성은 위치, 길이, 형태 등의 기하학적 특징을 지니며 이런 특징은 기준 마크를 찾기 위해 적절하고, 밝기의 변화, 크기 및 각도의 변화에 강한 특성을 지닌다. X, Y 축 이동 및 회전 할 수 있는 장비와 소프트웨어을 이용한 얼라인먼트 실험을 통하여 제안한 시스템의 성능을 검증하였다.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3608-3613
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• 2009

본 논문에서는 휴대용 단말기 적용이 가능한 mobile Radio Frequency Identification (m-RFID) system 을 위한 안테나의 설계 방법을 제안했다. 전기계 안테나와 자기계 안테나의 결합을 통하여 안테나의 휴대 단말 장착시 m-RFID 적용 방향으로 안테나의 패턴이 지향성의 특징을 나타낸다. 전기계 안테나는 PIFA 구조의 안테나를 사용하였으며, 자기계 안테나는 loop 형 안테나를 구현하였다. 목표 주파수 대역은 900 MHz 대역이며, 목표 이득은 4dBi 이상으로 설계 되었다. Ansoft 사의 HFSS 를 사용하여 시뮬레이션하였으며, 목표치 이상의 결과를 보였다. 제작된 안테나는 FR4 epoxy 기판 (h=1 mm, $\varepsilon_{\tau}=4.4$) 을 사용하여 제작되었으며, 시뮬레이션과 유사한 결과를 보였다.

• International Journal of Quality Innovation
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• 제4권1호
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• pp.160-174
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• 2003

This study researched an enterprise resources planning (ERP) implementation project at a printed circuit board (PCB) manufacturer. In depth research was achieved by participating and observing in an implementation project at an actual PCB manufacturer. It is hoped that this study will contribute a valuable reference resource for future PCB manufacturers that wish to select or implement ERP systems. The first step in implementing ERP software is to set a clear target. At the same time, the tasks of each department and the system of cooperation between departments must be clearly defined. In this way, the cycle time of each flow and the accuracy of data will both be improved. In order to ensure smooth implementation of an ERP project, the followings are key factors: (1) an ERP system that suits the PCB industry; (2) effective project management; (3) effective project cost/budget control; (4) project problem management system; (5) comprehensive implementation method and information technology (IT), etc. By keeping to these principals, Company A achieved rapid transactions, and lower total cycle times and inventory levels, and other such benefits that had been predicted.

• Journal of electromagnetic engineering and science
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• 제13권1호
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• pp.54-61
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• 2013

An equivalent model has been developed to estimate the electromagnetic immunity for integrated circuits under a complex electromagnetic environment. The complete model is based on the characteristics of the equipment and physical configuration of the device under test (DUT) and describes the measurement setup as well as the target integrated circuits under test, the corresponding package, and a specially designed printed circuit board. The advantage of the proposed model is that it can be applied to a SPICE-like simulator and the immunity of the integrated circuits can be easily achieved without costly and time-consuming measurements. After simulation, measurements were performed to verify the accuracy of the equivalent model for immunity prediction. The improvement of measurement accuracy due to the added effect of a bi-directional coupler in the test setup is also addressed.

• 한국멀티미디어학회논문지
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• 제7권8호
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• pp.1058-1065
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• 2004

단순 모니터에서 CPU, 메모리, 그리고 하드디스크를 갖춘 셋탑박스에 이르기까지 내장형 시스템은 다양한 응용에 사용되고 있다. 특히 휴대용 또는 소형기기에 멀티미디어를 서비스하는 경우가 증가하고 있고 이들 시스템에는 내장형 운영체제가 탑재되고 있다. 본 논문에서는 멀티미디어 서비스를 위한 내장형 리눅스가 탑재된 임베디드 시스템에서 응용 프로그램과 운영체제 커널사이의 메모리 복사 요구를 감소시키는 Null copy기법을 제안한다. 저성능의 컴퓨팅 파워 및 저용량의 메모리를 가진 내장형 시스템에서 연속 미디어를 네트워크를 통해 실시간으로 전송하고자 할 때 Null copy 기법은 시스템의 QoS를 만족시킬 수 있다. 웹 카메라를 내장형 리눅스 개발 보드에 장착하여 영상 전송 환경을 구축한 결과 Null copy 기법은 CPU 이용률 및 마감시간 실패측면에서 기존 커널에 비해 우수한 성능을 나타내었다.

• 한국소음진동공학회논문집
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• 제27권2호
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• pp.168-174
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• 2017

In this work, a piezostack single-stage valve (PSSV) system is proposed and its control performance is experimentally evaluated at high temperature up to $150^{\circ}C$. In order to achieve this goal, a PSSV system is designed and operating principle and mechanical dimensions are discussed. A displacement amplifier and an adjust bolt are used to generate target displacement and to compensate thermal expansion. Then, an experimental apparatus is constructed to evaluate control performance of the PSSV system. The experimental apparatus consists of a heat chamber, a hydraulic circuit, a pneumatic circuit, pneumatic-hydraulic cylinders, thermal insulator, electronic devices, sensors, data acquisition (DAQ) board and a voltage amplifier. The flow rate and displacement control performance of the valve system are evaluated via experiment. The experimental results are evaluated and discussed at different temperatures and frequencies showing the controlled flow rate and spool displacement.

• 공학교육연구
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• 제16권6호
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• pp.52-57
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• 2013

In this paper, the evaluation system in order to achieve the program education objectives of Accreditaion Board for engineering education of Korea, analyze the educational objectives evaluation tool case studies of programs that are run by each university, the program educational objectives to match the actual situation of university I have developed a distinction between questions the evaluation and assessment system. Configuration, execution, measurement, analysis, is a five-step mooring, the evaluation tool, is a graduate research you are currently using the most in Korea, the employer survey, education target assessment model of the program, employment trends of graduates, I decided to graduate focus group interviews. Distinction between questions, the evaluation also developed a questionnaire to derive the important keywords of education for each objectives. Improvement evaluation tool, the evaluation criteria is required, the University is preparing evaluate (NGR) in South Korea engineering education certification next regularly, requires research on semantic analysis of the results of measurement of the educational goals of the program in the future some.

• Journal of Biosystems Engineering
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• 제26권6호
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• pp.535-544
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• 2001

This study developed a manipulator for robotic harvester to harvest cucumber. The manipulator was designed and built fur transferring an end-effecter from a fixed point to a specified cucumber. Its development involved the integration of a manipulating system with a PC compatible, DC motors, geared boxes, timing belts, and a motor controller board. Software, written in Quick basic. combined the functions of motor control with various circumstances. In order to move smoothly and rapidly the manipulator, it's shoulder link and elbow link were minimized by using rotational inertial moment without a motor and a geared box. After 30 replications of exercising the manipulator, it was concluded that the precision values of the X, Y and Z axes were less than 0.5mm, 7.25mm and 0.35mm, respectively. The precision data indicated the manipulator was not missing any steps fur the harvester to reach a target cucumber.