• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.429-430
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• 2007

The enlargement of an electric power system network gives us much challenges concerning with network operation. In addition to it, the fast aging process of network equipments requires more chance to check and maintenance, and also the increase of heavy loaded facilities and the increase of the fault current in the network need to exchange with the larger facilities in capacity. Due to these reasons, outages trend to increase. Network solution studies for outages are performed mainly for two purposes. The first one is to find the countermeasures when the outage causes a violation of the network reliability criteria. And the second one is to minimize network constraints due to outages. There are so many outages around 400 for only one month. Therefore, in order to do case studies for outage, not only skilled persons are needed, but also many available tools to help properly. Concerning with proper tools, we will introduce a program which we developed to get informations concerned with network sensitivity, and an example to apply that program.

• 상하수도학회지
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• 제27권5호
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• pp.649-659
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• 2013

Real time control (RTC) can be broadly defined as a system that dynamically adjusts the operation of facilities in response to online measurements in the field to maintain and meet the operational objectives, both during dry and wet weather conditions. RTC adds a dynamic component that is actively adjusted in real time based on system conditions. In terms of reducing or eliminating sewer flooding, CSOs and/or managing flows, implementation of RTC has various benefits to sewer system operation. It has been emerging as an attractive approach, but related elements (such as framework for the application, its components and equipments, aspects to be considered) towards its application on sewer systems have not been throughly introduced so far. The main goal of this study is to review several applications of RTC and firm guidelines published abroad, and finally to provide a framework for the proper application of RTC on sewer systems.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.550-553
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• 2004

Recently, the demand for the Floating, Production, Storage, and Offloading facility (FPSO) which has some economic and technical advantages, has increased in offshore oil production areas. The 36,8000 DWT class FPSO was built in Hyundai Heavy Industries and will be installed in Offshore Angola. She dose not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise sources are contributing to the cabin noise of the accommodation are classified into three classes such as the machinery in the engine room and the deckhouse, HVAC system, and the topside equipments. In general, the noise regulation for the offshore structure is severer than that of the cargo ship and acceptable noise limit of cabin is specified as 45 dB(A). This paper describes the procedure of noise analysis, the countermeasures of noise control, and the measurement results of the quay trial. In order to minimize the noise levels, careful attention have to be paid by the special committee of experts from the initial design stage to the delivery. Proper countermeasures, considering the characteristics of sources and receiver spaces, were applied from the noise prediction and various experiment results. Finally, this ship was successfully delivered with excellent noise properties. The technology to minimize the noise levels for FPSO has been established throughout the construction of this ship.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.307-310
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• 2000

Recently, the demand for the Floating, Production Storage, and Offloading facility(FPSO) which has some economic and technical advantages, has increased in offshore oil production areas. The basic characteristics of a 343,000 DWT class FPSO which is being built in Hyundai Heavy Industries and shall be installed in offshore Angola, is almost same as that of oil carriers. However, she do not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise source contributing to the cabin noise of the accommodation, are classified into the machine in the engine room and the deckhouse, HVAC system, and the topside equipments. In general, the noise regulation for the offshore structure is much severer than that of the common commercial ships and the maximum acceptable sound pressure level of cabins is specified in 45dB(A). This paper describes the procedure of noise analysis along with its results. Noise analysis has been carried out for the case of emergency diesel generator running condition and the case of normal production condition and the results has been compared with the measurement results of the first case. Based on the results, proper countermeasures to reduce excessive noise level has been applied considering the characteristics of sources and receiver spaces and can be satisfied the specifications at all spaces.

• 한국해양학회지:바다
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• 제7권4호
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• pp.286-303
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• 2002

한국해양연구원에서는 1978년이래 해류계 계류에 의한 해류관측을 실시하였다. 본 단보에서는 한국주변의 연안역과 대륙붕해역에서 시도하였던 계류 형태와 계류 실패 사례를 소개하고자 한다. 천해역에서는 U-type 계류와 트롤방지 해저 계류장치를 이용한 해류관측 방법이 주로 이용되었다. 천해역에서 계류 실패를 피하기 위해서는 (1) 어로활동을 포함한 계류현장의 환경을 고려하여 적절한 계류 계획을 세워야 하며 (2) 계류기간과 수심 및 기타 예기치 않게 계류선에 영향을 줄 수 있는 제반 요인 등을 고려하여 적절한 계류용품이 사용되어야 한다

• 한국소음진동공학회논문집
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• 제18권1호
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• pp.110-122
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• 2008

Pneumatic vibration isolator typically consisting of dual-chamber pneumatic springs and a rigid table are widely employed for proper operation of precision instruments such as optical devices or nano-scale equipments owing to their low stiffness- and high damping-characteristics. As environmental vibration regulations for precision instruments become more stringent, it is required to improve further the isolation performance. In order to facilitate their design optimization or active control, a more accurate mathematical model or complex stiffness is needed. Experimental results we obtained rigorously for a dual-chamber pneumatic spring exhibit significantly amplitude dependent behavior, which cannot be described by linear models in earlier researches. In this paper, an improvement for the complex stiffness model is presented by taking two major considerations. One is to consider the amplitude dependent complex stiffness of diaphragm necessarily employed for prevention of air leakage. The other is to employ a nonlinear model for the air flow in capillary tube connecting the two pneumatic chambers. The proposed amplitude-dependent complex stiffness model which reflects dependency on both frequency and excitation amplitude is shown to be very valid by comparison with the experimental measurements. Such an accurate nonlinear model for the dual-chamber pneumatic springs would contribute to more effective design or control of vibration isolation systems.

• 한국식품조리과학회지
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• 제13권3호
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• pp.304-313
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• 1997

A survey was conducted to get information on the job attitude of cooks working for deluxe hotels at Bomun, Kyongju. Total 203 cooks participated the survey and the results were as follows: They believed that the most important factor for good cooking is the deep attention. Although 51% of the cooks estimated their level of expertise as average, 64％ of them believed that their level of cooking is higher than those of other areas. They indicated that an important factor to be a good cook is a sincere attitude but not an academic background or knowledge. However, they believed that their insufficient knowledge on cooking is the greatest hinderance for improvement of cooking skill. For promotion, the ability of cooking and human relationship were indicated as important factors. Cooks for Korean dishes had the best prospect, while Western cooking had relatively lower prospect among them. For the improvement of hotel cooking department, a recruitment of superior manpower, adjustment of hotel policy, expanded study opportunity, and proper arrangement of equipments were suggested in order.

• 교육시설 논문지
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• 제25권6호
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• pp.29-34
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• 2018

The purpose of this study is to plan a environment for creative education in university campus. According to the literature review, the necessity of improvement of educational program and physical environment is increasing because of rapidly social and industrial structure change. In this aspect, G university decided to make space for creative education utilizing unused space in campus. The space design concept was established as a cell based on the fact that the educational space was a place where students grow up and was named GNU IDEA Factory. The planning site was decided on the existing piloti to solve problems of lack budget and space. This space consisted of rooms for creative education, autonomous students' activity, and exhibition and was designed by organistic structure. In conclusion it was thought that GNU IDEA Factory would be a case of environment for creative education and activity if it was supported proper program and usable equipments.

• 한국음향학회지
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• 제26권6호
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• pp.286-292
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• 2007

해수연결 배관계에서 발생되는 주요한 소음원은 함 내부 탑재장비의 원활한 작동을 위해 해수를 순환시키는 해수순환 펌프이다. 이러한 펌프에서 발생되는 토널 성분을 가지는 유체전달 소음은 적절한 소음감소기를 통해서 감소되어야 한다. 본 논문에서는 실험적으로 유체전달 소음감소기의 음향 투과손실을 측정하기 위해서 해수연결 배관계의 끝단 반사가 존재하는 경우 배관 내의 음파를 입사파와 투과파로 분리하는 전달함수 기법을 제안하였다. 제작된 소음감소기 시험시편에 대한 이론적 투과손실과 제안된 기법을 통해 측정된 투과손실이 관심 주파수 영역에서 잘 일치함을 확인함으로써 기법의 타당성을 검증하였다.

• 한국농공학회지
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• 제17권4호
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• pp.3897-3920
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• 1975

Since the most of Korean dairy and cattle raising farms are too small to introduce western mechanized farming, it is necessary to develope small size equipments. This study has been carried to develop a rotary mower as on attachment of 8 to 10 horse powertiller which is widely spread in rural area. It will not ony be helpfull for the farmers to harvesting hay grass but also desirable to increase the power tiller utility. The protto type rotary mower designed through the fundamental investigations, has been modified and improved through the field trials, and a series of field tests has been carried to investigate its performance and economic feasibility comparing with existing vailable harvesting equipments. The results are as follows; 1. To increase the stability, two guide wheels are attached to both side of the protto type rotary mower. 2. To prevent the clinging of tall grasses, the vertical driving shafts are covered with cylindrical protectors. 3. The cutting height is adjustable in 8 steps from 2.5 to 20 centimeters by changing the length of guide wheel legs. 4. The practical Critical cutting speed were always higher than theoretical value in both case of single cutting blade and three when the cutting depth was 25 millimeter. 5. The peripheral speed of cutting blade was varied in response to the change of engine speed, mean while the peripheral speed was adequate as it was changhed from 25 to 35 meter per second when the power tiller is operated in proper working ground speed. 6. The time requirement to harvest 10 a were 88.7, 54.6 and 41.4 minutes for the first, second and third stage of ground speed respectively, and because of the difficulty of delivery, it was observed that operating with fourth stage of ground speed was not recomanendable when the grass height is taller than 90 centimeters. 7. The performance of rotary mower were 1.1-1.7, 1.4-4.0, 3.8-11.8 and 7.4-22.0 times of reciprocating mower, portable disc type cutter, hay scythe and ordinary sickle respectively. 8. When the slope exceeds, 20 degree the downward harvesting operation was impossible because of the excessive front end weight, while less than 5 degree of land slope did not effect in field operation. 9. Increased traveling spee caused higher cutting height and slight cutting failure, but seems not to effect to the gross yield, and the efficiency of cutting width were from 83 to 94 precent. 10. Tn rank of economy were rotary mower (3,2 stage operation), reciprocating mower, hay scythe, portable disc type cutter and sickle in order when the annul operation exdeeds 100 hours. From the above results, it is convinced that the protto type rotary mower is good enough to the livestock farmers as a hay harvesting equipment because of its economy, hardiness in operating and its out standing performance and hopefully it will contribute to the extension of Korean livestock farming.