• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.323-323
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• 2004

CNC 컨트롤러는 일반적인 공작기계나 특수한 가공기계를 대상으로 위치제어와 속도제어를 하는 장치로서, 기계적인 가공방식은 기본적으로 전통적인 방식에서 고정도화, 고속화, 고생산성화를 추구하는 기술로 발전하고 있다. 또한 다품종 소량생산을 위한 자동화와 무인화에 이르기까지 급속한 발전을 해왔다. 이러한 발전으로 CNC 컨트롤러는 여러 가지 일을 동시에 처리해야 하므로 멀티태스킹이 가능하여야 한다.(중략)

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.179-182
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• 2002

본 논문에서는 디지털 이퀄라이저에 대하여 검토하고, 대역 및 이득에 따라 Q-factor를 가변시키는 디지털 이퀄라이저 필터를 제안한다. 제안한 기법은 고정된 Q-factor를 사용하거나, 대역에 따라 Q-factor를 결정하는 기존의 방법들에 비해 가청 주파수 영역에서의 대칭성과 이득 리플 등의 측면에서 우수하고, 기존의 방법과 동일한 수준의 하드웨어 복잡도를 보인다. 또한, 중심 주파수 선정에 따른 성능 변화에 대해서도 고찰한다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.04a
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• pp.293-297
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• 1998

본 논문에서는 화상, 음성, 화이트보드 등과 같은 멀티미디어 자원들을 상호 연동하여 진행하는 참호참여환경 프레임워크인 DooRate이 갖고 있는 세션 진행 시 고정된 멀티미디어 자원을 사용하는에 따른 문제점을 개선하는 방법을 설계하였다. 이 설계를 통하여 다양한 형태로 실시간 세션을 변형시킬 수 있을 뿐만 아니라 불필요한 미디어정보의 전송을 제거할 수 있어 시스템 및 네트워크 부하를 줄일 수 있도록 한다. 진행중인 세션의 변환 명령 패킷의 신뢰성있는 전송을 위하여 RMTL(Reliable Multipoint Transport Layer)방식의 IP Multicasting을 설계하였다.

• Information and Communications Magazine
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• v.25 no.2
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• pp.63-72
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• 2008

본고에서는 세계전파통신회의(WRC)의 개요 및 역사를 살펴보고,2007년 개최된 WRC 논의 내용 중 위성, 방송, 고정 및 HAPS 분야에 대한 주요 결과 및 그 의미, 국내 파급 효과와 영향 등을 살펴보고자 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.221-222
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• 2021

본 연구는 Convolution Neural Network에서 사용되는 Convolution 연산기를 Systolic Array를 이용하여 구현한다. 두 개의 층으로 나뉜 연산기에 고정 소수점 값을 가지는 커널 값과 연속적인 입력을 넣고 정확한 출력이 나오는지 확인한다. 연산기 구현은 Verilog HDL로 하였으며 대조 연산은 Python에서 진행하였다.

• Resources Recycling
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• v.20 no.5
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• pp.64-68
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• 2011

The typical properties of manganese nodules are its high porosity and high specific surface area and manganese in nodules is existed as ${\delta}$-MnO$_2$. These properties suggest that manganese nodules ran be used as an adsorbent for heavy metal ions. This study investigated the practical applicability for the removal of copper ions in the waste water by manganese nodules as an adsorbent using fixed column and fix bed systems. Manganese nodules of 1kg (size 1-3 cm) can absorb 4.0g Cu in fixed column system and 2.3g Cu in fixed bed system from waste water for 3 hours respectively.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.154-157
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• 2004

Immobilized cells of Aspergillus niger was employed to produce citric acid by fermentation of milk factory waste water. A. niger ATCC 9142 as a citric acid production strain was cultured for 3 days and was entrapped with Ca-alginate bead about 2.5∼3.5 mm. The optimal pH and temperature were estimated to be 3.0 and $30^{\circ}C$, respectively. Dilution rate for fermentation was calculated to be $0.025 h^{－1}$ . Maximum amount of citric acid was obtained at 4.5 g/$\ell$ with the optimized fermentation condition. The yield of citric acid produced by immobilized A. niger ATCC 9143 was 70.3%. The yield was increased by 20% with immobilized cell, compared to that of the shake flask culture. Hence, the milk factory waste water is worthy to be used for the substrate of citric acid fermentation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.17-24
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• 2008

Recently, the importance of supplying the reliable electric power is increasing. therefore, the importance of diagnosis of power equipments is increasing also. Breaking insulation of stator windings is major cause of faults in high voltage generators. On-line PD (Partial Discharge) detection using Capacitive Coupler at stator windings is used widely to diagnose high voltage generator. However, precise PD(Partial Discharge) detection is impossible if detected signals are mixed with PD and noise signal. In this paper, we analyze detected signals using Capacitive Coupler at 13[kV] hydroelectric generator stator winding and suggest not hardware method but noise elimination algorithm for detecting PD of generator stator winding considering relation of periphery signals.

• Journal of the Korean Society of Safety
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• v.36 no.5
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• pp.71-78
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• 2021

There are regularly planned overhaul periods in thermal power plants, which involve the maintenance of the boiler of the power plants. However, thermal power plants workers are always exposed to risk during overhaul periods owing to the narrow space and significant dust inside the boiler. Therefore, it is essential to develop a safety monitoring system that is suitable for operating in this type of environment. In this study, we developed not only a worker three-dimensional (3D)-location monitoring system that can monitor and record the entry/exit of workers, their 3D-location, and fall accidents but also a method to secure the working environment and operation efficiency. This system comprises of a worker tag, which was equipped with an inertial measurement unit, a barometric pressure sensor, and a Bluetooth low energy (BLE), and the tags were given to each worker. In addition, the location of workers inside the boiler was measured using a pedestrian dead reckoning (PDR) method and BLE beacons. The location data of the workers tag were transmitted to the integrated database (DB) server through a gateway, and to the administrator monitoring system. The performance of the system was demonstrated inside an actual thermal power plant boiler, and the accuracy and reliability of the system were verified through a number of repeated tests. These results provide insights on designing a new system for monitoring enclosed spaces.

• Journal of radiological science and technology
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• v.31 no.4
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• pp.407-413
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• 2008

Measurements of the peripheral dose were performed using a 2D array ion chamber and solid water phantom for a $10{\times}10cm$, source-surface distance (SSD) 90cm, 6 and 15MV photon beam at depths of 0.5cm, 5cm through $d_{max}$. Measurements of peripheral dose at 0.5cm and 5cm depths were performed from 1cm to 5cm outside of fields for the dynamic wedge and physical wedge $15^{\circ}$, $45^{\circ}$. For 6MV photon beam, the average peripheral dose of dynamic wedge were lower by 1.4% and 0.1% than that of physical wedge For 15MV photon beam, the peripheral dose of dynamic wedge were lower by maximum 1.6% that of physical wedge. The results showed that dynamic wedge can reduce scattered dose of clinical organ close to the field edge. The wedge systems produce different peripheral dose that should be considered in properly choosing a wedge system for clinical use.