• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.13 no.2
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• pp.21-26
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• 1977

The author operated with a six seam trawl net by the stern trawler, No. 85 Parto, 499 GT, 2,200ps, in the Atlantic coast of Africa, from June, 1975 to October, 1977. In the term, towing speed and warp tension were determined, and trawling condition was observed. 1. The condition of trawling was good when the tension was less than 7.5ton. 2. 290 RPM, $13.5^{\circ}\;to\;13.8^{\circ}$ of pitch angle, and 3.5 to 4 knots of towing speed was considered as optimum for the trawler in the relation to the engine condition.

• Journal of Energy Engineering
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• v.11 no.4
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• pp.317-323
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• 2002

This paper proposed the calculation method of the generation operating avoided cost to cost-effectiveness evaluation of energy conservation programs that compounded the Proxy Plant Method and Load Decrement Method. This method introduced an operating index of the Energy Efficiency Demand-Side Management (EEDSM) resources based on the end-user's behaviors on the electricity power usage. The operation index is applied to calculate the hourly operating capacity of diffused high-efficiency appliances. And the operating capacity on the peak load hours for reference load is computed through the reduction of the peak load that contributes to that hour. Also, the proposed method evaluated the effect of EEDSM resources. The IEEE-RTS is adopted as a sample system to analyze impacts of an EEDSM. This paper, we have analyzed the effect of EEDSM upon the changes in the generation of generator, generation cost and the system marginal price (SMP). This method can be used to evaluate the impact of the diffused DSM resource and to estimate the impact in short-term EEDSM program. Further, result of the calculation can be utilized to pabulum for effect analysis of EEDSM resources.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.3
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• pp.151-160
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• 2014

In this study, the effect of the automotive haptic-seat technology which can transmit the driving information by the vibro-stimulus from the seat was investigated to overcome previous system's limitation relied on the visual and audial method and to help handicap driving. A prototype haptic seat cover with 30 coin-type motors and driver module were developed for this sake. In an experiment of seat vibration stimulation being performed under virtual driving situation by targeting the elderly aged over 65 years old, average score of test subjects for total vibration recognition was 3.5/4 points and recognition rate of 87.5% was represented. In addition, a result that all the test subjects totally recognized overspeed warning signal of 4 times was represented. As a result of statistical analysis for vibration recognition score by each group depending on TMT score, a significant difference was not found and a result that tactile function of which vibration is recognized even by the aged whose visual, perceptional function is declined showed an equal ability was obtained.. In this study it was shown that the seat vibration stimulus could be used to transfer the old drivers' information while driving.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.1
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• pp.1-7
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• 2014

In this study, the effect of the automotive haptic-seat technology which can transmit the driving information by the vibro-stimulus from the seat was investigated to overcome previous system's limitation relied on the visual and audial method and to help handicap driving. A prototype haptic seat covers with 30 coin-type motors and driver module were developed for this sake. A driving simulator on the 6-DOF motion-base was used for driving situation and we executed the seat vibro-stimulus test with 10 young participants who have normal tactile sense. The haptic recognition ratio by 30 locations was measured and analyzed in the result. The intensity of vibro-stimulus was adjusted by input voltage of motors (1.5V,2.5V,3.5V). All vibro-stimulus locations at 2.5V and 3.5V could be recognized by all participants and even in the lowest recognition ratio of 1.5V. The results showed that the seat vibration stimulus could be useful to transfer the drivers' information while driving.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.2
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• pp.107-114
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• 2007

Islanding of PV systems occurs when the utility grid is removed but the PV systems continue to operate and provide power to local loads. Islanding is one of the serious problems in an electric power system connected with dispersed power sources. This can present safety hazards and the possibility of damage to other electric equipments. In the passive method, the voltage and frequency of PCC are measured and it determines islanding phenomena if their values excess the allowed limits. If the real and reactive power of RLC load and those of the PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding operation in the region where the passive method can not detect it. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new islanding detection method using automatic phase-shift is proposed and its validity is verified through the simulation and experimental results.

• Membrane Journal
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• v.12 no.3
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• pp.143-150
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• 2002

Electrodialysis(ED) is a reliable and effective process for the separation and concentration of ionic compounds. However, commercial uses of ED are often hindered by the cost of the stack that mainly resulted from the ion-exchange membrane cost. In order to minimize the membrane cost, it is desired to operate ED at the highest practicable current density. In an actual ED system the high current operation is limited by the concentration polarization phenomenon. This article illustrates the transport phenomena of ions through ion exchange membranes using current-voltage relations as a characterizing method. Also recent studies on electroconvection and water-spitting phenomena caused by concentration polarization were reviewed.

• Journal of the KSME
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• v.33 no.5
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• pp.405-413
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• 1993

원자로용기의 노심대와 노즐의 압력 . 온도 곡선에 대한 배경 및 적용을 살펴보았다. 그러나 원 자로 용기의 실제 압력 . 온도 곡선은 노심대와 노즐 이외에도 플랜지, 수압 및 수밀시험, 노심 임계, 최저운전온도, 계기오차 등을 고려해야 한다. 이 글에서는 시간당 100.deg. F의 가열 및 냉 각에 대서만 고려하였으나 시간당 10.deg. F, 40.deg. F 등 다른 가열 및 냉각률에 대해서도 고 려하여야 한다. 따라서 원자로용기의 실제 압력 . 온도 곡선은 이 글에서 기술한 것보다 훨씬 복 잡하다. 그러나 어느 경우에라도 압력 . 온도 곡선을 구하는 기본적인 이론 및 방법은 이 글에서 기술한 내용에 기초를 두고 있다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.37-40
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• 2008

This paper presents the results of a simulation to analyze the effects of voltage sag on high-pressure discharge lamp(400[W]). In this paper, voltage sag is considered a reduction between 0 and 0.9[p.u] in nominal voltage magnitude, with duration between 0.01 and 90cycle. The simulation results depict the characteristics of the lamp about operating limits during voltage sag by the magnitude and duration of sag in CBEMA curve.

• 전기의세계
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• v.39 no.8
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• pp.48-54
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• 1990

일본에서는 도시바, 미쓰비시, 관서전력, 동연사업단, 일본원자력연구소 등이 전문가 시스템 개발과 적용 연구에 심혈을 기울고 있으며 현재 상당한 기술 수준에 이른 것으로 평가되고 있다. 프랑스와 캐나다 등에서도 전문가 시스템의 원전 적용에 대한 연구를 수행하고 있으나 아직 초기단계로 보여진다. 우리나라의 경우 이 분야에 대한 연구가 학계와 관련연구기관, 전력회사등에서 이제 시작되고 있으며 앞으로 더욱 활발한 연구와 투자로 선진국과의 기술격차를 줄이고, 우리 스스로 전문가 시스템을 개발할 수 있는 능력을 길러야 할 것이다. 현재 선진국에서 이 분야에 대한 급속한 개발 추세로 보아 앞으로 많은 분야에 전문가 시스테을 도입할 경우, 현재의 기술로 가능한 수준과 그 한계를 명백히 하고, 이용 목적이나 적용대상을 명확히 정한후 시스템을 도입 적용해야 할 것이다. 국내의 기술개발현황을 고려해 볼때 우선 사고 진단 및 처방, 운전원 의사 결정 지원분야, 핵연료 재배치 계획 분야, 운전원 훈련분야등에의 도입이 바람직하며 아주 기초적인 것부터 적용하여 경험과 기술을 축적한 수 점진적으로 기술수준이 높은 전문가 시스템을 도입 적용하여야 할 것이다.

• 기계와재료
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• v.22 no.1
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• pp.54-64
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• 2010

공작기계의 고속화, 다축화, 복잡화에 따른 열변형 오차가 공작기계에서 발생하는 오차의 대부분을 차지하고 있다. 이러한 열변형 오차를 최소화 하기 위해 공작기계의 발열부에 차가운 오일을 공급하여 냉각함으로써, 열변형을 제거하는 장치가 오일쿨러이다. 오일쿨러는 제어 방법에 따라 On-off, 가스 바이패스, 인버터 방식 등이 사용된다. 초정밀 공작기계에는 주로 가스 바이패스 및 인버터 방식이 사용되는데, 인버터 방식의 경우 고가(高價)인 관계로 주로 옵션 형태로 사용된다. 가스 바이패스 방식 오일쿨러는 인버터 방식에 비해 가격이 저렴하고 구조가 간다하며 정밀한 온도제어를 할 수 있지만 부하가 낮은 경우 구조적인 한계로 인해 온도제어 불안정을 발생시킨다. 본 연구에서는 기존 바이패스 방식 오일쿨러에서 나타나는 문제점을 해결하고 보다 정밀한 온도제어를 위해 2개의 전자밸브를 갖는 듀얼 밸브 방식 오일쿨러 시스템을 개발하였다. 개발된 듀얼 밸브 오일쿨러 시스템의 성능검증을 위해 정격운전, DIN 8602 규격, ISO/DIS 230-3 운전모드에서 성능을 비교/분석하였다.