• Journal of Fisheries and Marine Sciences Education
• /
• v.19 no.2
• /
• pp.278-287
• /
• 2007

Since traffic congestion ratio at any given port fluctuates on the number of arriving and departing vessels, the total tonnage of freight volume being handled, and the number of berth in operation and other factors, there exists a need to numerically analyze the waterway traffic volume. However, there are no effective regulations in regards to the waterway traffic analysis prior to expansion of a port facility. The current analysis requires the traffic analysis in relation only to the width of the waterway, which clearly falls short of achieving a comprehensive evaluation study that could be used in consideration of port expansion.This study provides five scenarios to execute a comprehensive evaluation study and base for the sensitivity study by analyzing the scenarios. As a result of the sensitivity analysis, the A, B, and C scenarios varies the average arrival ratio of the berth shows 1.1, 1.19, and 1.28 times of delays respectively. Also, The D and E scenarios take place malfunctions of pier shows 1.21 and 1.53 times of delays respectively. Therefore, various strategies of harbor development and method of harbor management are needed for the flexible correspondence to the environmental changes such as the excessive increasing of the freight volume and often taking place of malfunctioning.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.29 no.3
• /
• pp.119-126
• /
• 2017

Recently, ground source heat pump systems are being used in buildings for cooling and heating to reduce greenhouse gas and save energy. However, ground source heat pump systems mainly use the vertical closed-loop geothermal system design rather than the open-loop geothermal system design. This is due to a lack of knowledge and few research feasibility studies. In this research, a dynamic thermal analysis numerical simulation based on a standard house model was conducted for an open-loop geothermal system. Based on heating load analysis results, the life cycle costs of a standard house using an open two-well geothermal system were analyzed and compared with a vertical closed-loop geothermal system, and a diesel boiler. As a result, it was found that using an open two-well geothermal system shows economic return on investment after three years.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.10a
• /
• pp.290-294
• /
• 2001

Satellite data, with Sea Surface Temperature(SST) by NOAA and Sea Level(SL) by Topex/poseidon, are used to estimate characteristics on the variations and correlations of SST and SL in the East Asian Seas from January 1993 through May 1998. In the oceanic climate, the variations of SL shown the high values in the main current of Kuroshio and the variations of SST shown not the remarkable seasonal variations because of the continuos compensation of warm current by Kuroshio. In the continental climate, SL shown high variations in the estuaries(the Yellow River, the Yangtze River) with the mixing the fresh water in the mouth of estuaries of the saline water in the coasts of continent and SST shown highly the seasonal variations due to the climatic effect of continents. In the steric variations in summer, the eastern sea of Japan, the East China Sea and the western sea of Korea shown the increment of sea level with 10~20cm. But the Bohai bay in China shown relatively the high values of 20~30cm due to the continental climate. Generally the trends of SST and SL increased during all periods. That is say, the slopes of SST and SL presented 0.29$^{\circ}C$/year and 0.84cm/year, respectively. The annual and semi-annual amplitudes shown a remarkable variations in the western sea of Korea and the eastern sea of Japan.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.1
• /
• pp.27-33
• /
• 2013

Helmet Mounted Display(HMD) has great advantages on the navigation and mission symbologies for the pilot's forward looking display and, therefore, has been remarkably drawing attention as the up coming display of the next generation aircraft. The essential technology to process the Line of Sight-Foward(LOS-F) data in real-time is to estimate exact helmet situation and position. In this paper, we research a acoustic helmet tracking technique. For the reason that mechanical acoustic noises might interfere with Helmet Tracking System(HTS) and unnecessary acoustic noises are inevitable when using acoustic technique, this approach has not been adapted. In order to overcome this problem. We propose that acoustic wave of which the wave length is longer than audio frequency and, especially, we used beating signal envelope which is composed of two close high frequency.

• Honam Mathematical Journal
• /
• v.1 no.1
• /
• pp.61-75
• /
• 1979

In this explanation. we shall describle how the de Rham's cohomology on a n-dimensional $C^{**}$-manifold is constructed. The Čech's cohomology defined by only topological structure of $C^{**}$-manifold has a crack that it is dependent on the covering of a $C^{**}$-manifold. At the end of explanation we shall prove that the de Rham's cohomology is isomorphic to Čech's cohomology which is made by simply covering.

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.1
• /
• pp.98-103
• /
• 2000

This paper suggests a method to recognize the various defect patterns of a cold mill strip using a binary decision tree automatically constructed by a genetic algorithm(GA). In classifying complex patterns with high similarity like the defect patterns of a cold mill stirp, the selection of an optimal feature set and an appropriate recognizer is important to achieve high recognition rate. In this paper a GA is used to select a subset of the suitable features at each node in the binary decision tree. The feature subset with maximum fitness is chosen and the patterns are classified into two classes using a linear decision function. This process is repeated at each node until all the patterns are classified into individual classes. In this way, the classifier using the binary decision tree is constructed automatically. After constructing the binary decision tree, the final recognizer is accomplished by having neural network learning sits of standard patterns at each node. In this paper, the classifier using the binary decision tree is applied to the recognition of defect patterns of a cold mill strip, and the experimental results are given to demonstrate the usefulness of the proposed scheme.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.1
• /
• pp.24.2-24.2
• /
• 2011

13C이후 동아시아에서는 대규모의 천문관측시설들이 건설되었다. 중국 원대(元代) 북경(北京)에는 사천대(司天臺, 1276)라는 천문대가 축조되었다. 이 천문대 위에는 간의, 앙의, 규표를 비롯한 다양한 천문의기가 사용되었다. 명대(明代)에는 사천대의 자리에 관성대(觀星臺, 1442)가 만들어진다. 이후 관성대는 청대(淸代)에 관상대(觀象臺, 현재 古觀象臺로 불림)로 이름이 변화되었다. 관상대 위에는 청대에 제작한 8종의 천문의기가 남아 있다. 원대 등봉(登封)에도 대규모 천문대인 관성대(觀星臺)가 축조되었다. 현재 등봉에는 관성대와 40척 규표(圭表)가 남아있다. 조선에서는 1433년 간의대(簡儀臺)가 건설되었다. 간위대 위에는 간의(簡儀)와 정방안(正方案)을 설치하였다. 간의대 주변에는 보루각(報漏閣, 자격루 운영)과 흠경각(欽敬閣, 옥루 운영)이 위치해 있고, 다양한 천문관측기기가 설치되었다. 임진왜란을 거치면서 간의대 주변의 천문시설들은 대부분 파괴되었다. 이후 일부 관측기기가 새롭게 복원되었지만 조선 초기의 운영 형태는 불가능하게 되었다. 그런데, 간의대는 조선 후기까지 천문관측대로서의 위상을 유지하였다. 간의대 위에 놓여진 관측기기에 대한 뚜렷한 언급은 없었지만 천상의 이치를 논하거나 세종의 공덕을 기리는 공간으로 활용되었다. 우리는 간의대 문헌자료를 분석하고, 중국에 남아있는 천문대 유적을 조사하여 간의대 복원을 위한 기초연구를 수행하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.12 no.1
• /
• pp.93-102
• /
• 1998

This paper describes to control system for AC to DC converter which has been widely used to power source in industrial factory and domestics. In this paper, three-phase PWM AC to DC Boost converter that operates with unity power factor and sinusodial input line currents is presented. The current control of this converter is based on the predicted current control strategy with fixed switching frequency and the line currents track to reference currents within one sampling time interval. By using this control strategy low ripples in the output current and the voltage as well as fast dynamic response are achieved with small dc link capacitance employed.ployed.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.4
• /
• pp.366-373
• /
• 2011

The magnetic switch used in pulsed-power applications is superior in its high repetition rate, high stability, and long lifetime. But magnetic switch was optimized switching operation by manual control. When the load changes, the switching state can not be optimized automatically. In this paper, the auto control method of magnetic switch for high pulsed-power proposed. The magnetic switch is used capacitor charging power supply for high-voltage compressor. The proposed method can be optimized an efficiency of the system by magnetic switch auto control according to load variation. And the proposed method verify the experimental results.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.2
• /
• pp.82-88
• /
• 2004

To evaluate the tidal flow around the transmission type harbour structures, the numerical models considering hydraulic resistance are used. The traditional governing equations of depth-integratef hydrodynamics are modified by using of the drag force term. As a numerical model to evaluate the rate of tidal exchange, the Random-walk method is used. The models are applied in a design of the pile-supported pier structures in Busan harbour site, Korea, where the flow speed and the tidal exchange are more promotive than the case of non-transmission structure. The developed model will be applied usefully to design the transmission type structure in the ocean space.