• Proceedings of the KIEE Conference
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• 2007.07a
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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.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.4
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• pp.286-303
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• 2002

Korea Ocean Research and Development Institute (KORDI) has attempted moored current measurements since 1978. This note describes mooring types and failures of moorings deployed in coastal and continental shelf regions around Korea. Taut-wire U-type mooring lines and trawl-resistant bottom mounts have been mainly used in shallow seas. In order to avoid the failure of moorings in the shallow seas, it is needed to (1) design a proper mooring plan considering local mooring environments including fishing activities and (2) use adequate mooring equipments and parts considering mooring period, depth, and other factors that could affect the mooring unexpectedly.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.1
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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.

• Korean journal of food and cookery science
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• v.13 no.3
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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.

• Journal of the Korean Institute of Educational Facilities
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• v.25 no.6
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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.

• The Journal of the Acoustical Society of Korea
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• v.26 no.6
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• pp.286-292
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• 2007

The dominant source of noise in a sea-connected piping system is usually due to a seawater cooling pump which circulates seawater to operate onboard equipments normally, and so its water-borne noise with some tonal frequencies should be reduced using proper silencers. In order to obtain the transmission loss of water-borne noise silencers experimentally the present paper suggests a transfer function technique that acoustic wave in the piping system is decomposed into its incident and transmitted components when the reflection at the termination of the system exists. Good agreement in the interested frequency range with theory and the proposed technique shows the validity of the technique.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.4
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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.