• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.461-464
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• 2011

Rail transport has been considered as an environmental-friendly transport mode compared with other transport modes such as ship, truck, and aircraft. However, rail industry can not avoid a duty of alleviating Greenhouse gases emission owing to the Korean government polices for green growth which is an economic paradigm that simultaneously pursues growth and environmental improvement. The purpose of this research is to develop a methodology of determining an economic speed of freight train to be green freight train by considering fuel cost, environmental cost, and time cost. In the methodology, we first define a cost function based on cost factors and then suggest an economic speed of freight train by deriving a property.

• 한국철도학회지
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• 제9권2호
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• pp.19-24
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• 2006

Green gas emissions Trading System(ETS) came into effect in the Europe last year 2005. All transport modes have tried to reduce green gas emission and EU member countries are promoting the use of environmental friendly transport mode to avoid economic loss due to green gas emission. Besides ETS, rapidly rising of oil price and peak oil urge to invest more in the environmental friendly public transport mode and to discourage the use of private cars. The operation of KTX is estimated to bring external cost reduction up to 570 bil. won in 2004 based on European external unit costs of transport modes. This result implies that the expansion of high speed rail network and reconsideration of East-West high speed rail network which is not considered because of weak economic validity is required.

• 한국지능시스템학회논문지
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• 제10권4호
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• pp.330-337
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• 2000

본 논문은 10개 교차로를 연동제어를 할 수 있는 새로운 교통체제 개념을 제안한다. 예를 들어서 오늘 야구경기가 8시경에 열린다고 하면 야구경기가 시작하기 전 1 시간 혹은 1시간 혹은 1시간 30분전에 교통량이 증가할 것이다. 이럴 때에는 아무리 우수한 전자 신호등 시스템도 최적녹색시간을 예측할 수 없다. 그러므로, 본 논문에서는 평균 승용차 대기시간을 최소화하고 평균 주행속도를 향상하기 위해서 퍼지규칙 및 신경망을 이용한다. 모의실험결과 제안된 연동 녹색시간이 연동 녹색 시간을 고려하지 않은 전자신호등보다 평균 승용차 대기시간을 줄일 수 있음을 입증했다.

• 수산해양기술연구
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• 제47권4호
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• pp.327-337
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• 2011

This study was conducted to develop energy-efficient LED lamps with an excellent fishing performance for an anchovy scoop net by comparing the functions of 6 different lamps- incandescent, blue LED, green LED, white LED, yellow LED and red LED lamp. We used incandescent and red LED lamps only for the initial test and then excluded because those showed the lowest herding capacity. According to the result, yellow LED showed lower herding capacity in comparison with the blue, green and white one. Although the herding performance of the blue, green and white LED was similar in almost tests, herding speed to the each light was different. The anchovies were gathered into the blue LED as the speed of 39.88cm/s that was the fastest. Green LED was the second as the speed of 33.28cm/s. White LED was the slowest as the speed of 26.73cm/s. We will have field tests because we found the result that yellow LED's herding performance was better than green LED's for 5 seconds comparing after starting in some tests.

• 대한방사선기술학회지:방사선기술과학
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• 제11권1호
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• pp.3-16
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• 1988

Author has made an experiment on absolute speeds of 18 screenfilm combinations that have been on sale in Korea, with various beam qualities. At this time, the beam qualities were 60kVp with the ANSI extremity phantom, 80kVp with the ANSI chest phantom and 85kVp with 20 mm aluminium filter under scatter free condition. The obtained results were as follows; 1. When three independent measurements were performed, the percent standard deviations of mAs quantities of 1.0 + fog were decreased by the hardening of the beam quality, and the decreasing tendency was somewhat great in the blue systems. 2. Generally, the increasing tendency of absolute speeds was distinct by the hardening of the beam quality in the green systems. Conclusively, the green systems were more strongly dependent upon the beam quality rather than the blue systems. Therefore, the relative speed of green systems to blue systems were great under the same condition. 3. Differences in the green systems were kept almost constant even though the beam qualities were changed. 4. They were shown the mutual relationship of absolute speed and relative speed rather than independent.

• 한국세라믹학회지
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• 제44권10호
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• pp.568-573
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• 2007

For the manufacturing lightweight fine aggregate, clay and waste material was formed by pelletizer. The fine aggregate of 1-5 mm diameter was formed by diameter 76 cm pelletizer disc. Pelletization variables were : (1) pelletizer disc angle, (2) speed of revolution of pelletizer, (3) added pelletization time. Green and sintered aggregate were measured specific gravity, absorption rate and average size. The optimum condition were found that the pelletization variables were angle at $70^{\circ}$, speed of revolution of pelletizer at 23.2 rpm, and water/solid ratio at 1/5. At these conditions, it was formed that fine aggregate green whose average size was $2.0{\sim}3.35mm$. Specific gravity and average size are increased with low angle of disc and fast revolution speed of disc. Specific gravity and average size were not distinctly influenced by added pelletization time. Sintered aggregate was distinctly influenced by properties of green.

• 신재생에너지
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• 제16권2호
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• pp.14-19
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• 2020

Recently, a project to build a carbon zero island with no carbon emissions has been carried out by replacing diesel generators with renewable energy sources in island areas where diesel generators supplied local loads as independent systems. To minimize damage to the lives of islanders, low noise wind generators should be installed by adjusting the rated speed. In islands with low loads, wind turbines that are more efficient than medium-sized wind turbines should be installed. In this study, the generator field analysis and characteristics were analyzed to develop 230 kW-class low wind medium-wind turbine technology. The electromagnetic field analysis program used Maxwell. As a result, the cogging torque was reduced, and the initial maneuver wind speed and loss value were lowered. Hence, the output amount was increased with high efficiency.

• 대한조선학회논문집
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• 제54권1호
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• pp.34-42
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• 2017

In rough seas, green water shipped on board may impose quite large impact loads on the structures on deck and sometimes result in structure damages. One of the essential tasks of the naval fluid engineers is to provide the design impact loads which are needed for proper design of the structure strength against the green water impacts. Computation of the design impact load due to green water needs first a process to find the sea condition and the ship cruising condition which cause maximum green water impacts on structures as well as other succeeding processes to compute ship motion responses, green water flows and impact loads. Also, as a bold and practical process, it is needed that the irregular real seas are to be substituted by design regular waves which are equivalent in view points of green water impacts. In this paper, the whole processes to compute the design green water loads acting on bow structure are set up creatively. And the green water design impact loads acting on the box-type structure of a high-speed ship's bow are computed and discussed.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.260-277
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• 2021

The appropriate radiation conditions of ship motion problem with advancing speed in frequency domain are investigated from a theoretical and practical point of view. From extensive numerical experiments that have been conducted for evaluation of the relevant radiation conditions, a hybrid radiation technique is proposed in which the Sommerfeld radiation condition and the free surface damping are mixed. Based on the comparison with the results of the translating and pulsating Green function method, the optimal damping factor of the hybrid radiation technique is selected, and the observed limitations of the proposed hybrid radiation technique are discussed, along with its accuracy obtained from the numerical solutions. Comparative studies of the forward-speed seakeeping prediction methods available confirm that the results of applying the hybrid radiation technique are relatively similar to those obtained from the translating and pulsating Green function method. This confirmation is made in comparisons with the results of solely applying either the free surface damping, or the Sommerfeld radiation condition. By applying the proposed hybrid radiation technique, the wave patterns, hydrodynamic coefficients, and motion responses of the Wigley III hull are finally calculated, and compared with those of model tests. It is found that, in comparison with the model test results, the three-dimensional Rankine source method adopting the proposed hybrid radiation technique is more robust in terms of accuracy and numerical stability, as well as in obtaining the forward speed seakeeping solution.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1340-1345
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• 1993

Five textural characteristics , epicarp strength, deformation , firmness , toughness and penetration time were calculated from force/deformation curves obtained by pressure testing tomato fruits. The fruits were harvested at either the mature-green or red maturity stages. The effects of changing the probe diameter and cross-head speed were investigated on force/deformation characteristics of tomatoes. It was confirmed that increasing of cross-head speed and probe diameter highly significantly effect all textural of the characteristics mentioned above , except epiarp strength of red tomatoes at 200 mm minute cross-head and penetration time of red and green tomatoes after 200mm minute and 100 mm minute cross-head respectively.