본 연구에서는 국내외적으로 환경문제 및 에너지절감의 일환으로 직류배전시스템을 선박에 적용하려는 연구 및 실증이 활발히 수행되고 있으며, 발전기를 직류배전시스템에 적용하기 위해서는 가변속 엔진을 적용하여 저부하 영역에서 발전기의 엔진 회전수를 줄여 연료소모량을 절감할 수 있는 방안이 제시되고 있다. 본 논문에서는 기존의 디젤발전기를 이용하여 발전기 컨트롤러, 가버너, AVR 을 이용하여 직류배전용 가변속발전기를 구성하였으며, 발전기의 시스템 구성 방법, 가변속 발전에 따른 전력품질 시험(전압 및 주파수 변동특성, 부하변동 특성)을 통해 가변속 발전기의 전력특성을 분석 하였다. 가변속 발전기의 전압(250 ~ 440 VAC) 및 주파수(34 ~ 60 Hz)는 정격의 60 ~ 100%로 구성하였으며, 엔진은 1100 ~ 1800 rpm 범위에서 운전되도록 설정 하였다. 부하변동에 따라 발전기의 엔진속도를 변경 시켜서 발전기 출력의 전압, 전류, 주파수가 전력량에 따라 안정적으로 변동되는 것을 확인하였다.

For increase the game speed, game systems apply a multi-threading. The popularization of multi-core system accelerates multi-threading also. Multi-threading brings high performance, but this is not ease to apply the game logic. Because many multi-core system share the memory, if two or more threads access the same memory region, they can be conflicted. Multi-threading uses Lock method to prevent the conflict, but Lock method reduces the performance. For increase the performance, programmer can use Lock-Free method. In this case, we found strange phenomenon that Lock-Free queue operates incorrectly, and this phenomenon has been accelerated by number of threads. In this study, we analyzed the input output of the Lock-Free Queue in multi-core system.

PURPOSES: The purpose of this study is to develop a method for distribution between superelevation and side friction factor by increasing design speed. METHODS: First of all, a method for distribution between superelevation and side friction factor and a theory for the functional formula of side friction factor in compliance with horizontal radius applied in South Korea and the United States are considered. Especially, design speed of 140km/h and numerical value of design elements are applied to the theory for the functional formula of side friction factor in AASHTO's methods. Also, the anxiety EEG upon running speed is measured to reflect ergonomic characteristics through field experiments at seven curve sections of the West Coast Freeway, and this data is applied to graph for the functional formula of side friction factor. RESULTS : Matching side friction factor against the anxiety EEG, the results that a critical points of driver's anxiety EEG sharply increase locate under existing parabola are figured out. CONCLUSIONS : Therefore, we could get a new type of the functional formula that driver's driving comfortability is guaranteed if the existing the functional formula of side friction factor goes down under boundary of the critical points of the anxiety EEG.

In general, a valve body of the automatic transmission(AT) is controlled by the clutch, the brake and lubricating oil flow in a hydraulic system and lubricant flow for each valve can be adjusted independently. To increase the lifetime of AT, the lubrication flow rate in a valve body for a 6 speed AT based parallel hybrid electric vehicle must be provided with proper oil distribution and control. In this study, we carried out several experiments without the inner parts of AT and with a AT assembly. The variation of the flow rate on oil temperature and pressure between an oil supply port and the outlets of the lubrication port was evaluated and analyzed. In the case of AT without the inner parts, it was evident that as the oil required for an operation of the clutch and brake was discharged from the outlet port, the flow rate from each lubrication port is decreased. However, the flow rate of the AT assembly was slightly increased. In addition, the lubrication flow rate was increased with increasing the oil temperature, and also it was reduced with increasing the oil pressure. Details of the resulting data are discussed.

건물 주변의 빌딩바람을 예측하고자 강한 3차원 난류장에서 PIV시스템을 사용하여 건물을 모양별, 높이별로 분류하여 약 20가지의 풍동실험을 실시하였다. 형상별 실험에서는 정사각형, 직사각형, 원형 건물과 정사각형에서 4모서리를 따낸 모서리 절삭 사각형 건물을 풍향 0o와 45o로 하여 각각 풍속을 측정하였고, 높이별 실험에서는 정사각형, 직사각형, 원형 건물을 Full Scale 높이 150m, 90m, 60m, 30m로 달리하여 각각 풍향 0o, 45o로 측정하였다. 이 PIV 실험결과를 CFD시뮬레이션 결과와 비교하여 초고층 건물 주변의 강한 3차원 난류장 기류해석에 PIV시스템에 의 한 풍속 측정이 가능한지에 대해 그 유효성을 검토하였다.

The W/O emulsion was formed by mixing hydrophobic nonion surfactants of span 80 and tween 60 with kerosine, and by adding sodium silicate aqueous solution. Precipitating the W/O emulsion by sodium bicarbonate resulted in spherical silica particles. Shape and size distribution of silica particles were observed. The particles were spherical and they have narrow size distribution. Particle sizes were 9.29, 7.39 and 5.73 μm at homogenizer speed of 2500, 3000, and 3500 rpm, respectively. The particle size was decreased by increasing agitation speed due to the formation of emulsion droplet. At fixed agitation speed, absorbed paraffin oil weight were measured and the SiO2/Na2O mole ratio effects on particle size were investigated. Particle size was decreased by increasing the mole ratio of SiO2/Na2O.

The speed of vertical migration and the volume backscattering strength of the scattering layers during the evening and morning transitions between day and night were measured in November 1990-1992 in thermally stratified waters of the East China Sea. Acoustical measurements were carried out using a scientific echo-sounder operating at t재 frequencies of 25 and 100kHz, and using an echo-integration system connected with a micro-computer. Biological sampling was accomplished by bottom trawling to identify fish species recorded on the echo sounder, and the species and length compositions were determined. The values of scattering strength were allocated to group of fishes according to the fish traces on the echo recording paper and the species composition of trawl catches. The vertical velocities of migration derived from the changes in the depths and the values of peak scattering strength of the dense layer vertically migrating toward the bottom or toward the surface. The trawl data suggest that snailfish and fishing frog were the most abundant fishes in all research stations. As sunrise approached, the fish formed a strong concentration just above the thermocline. The the highest values of scattering strength in the entire water column appeared in the depth strata above the thermocline just before the begining of downward migration. As soon as the fish began to migrate downwards across the thermocline, the values of the scattering strength in the depth strata above the thermocline rapidly decreased, while the values for the scattering layer moving slowly toward the bottom gradually increased. During the 1992 surveys, the speed of the vertical migration was estimated to be 0.38m/min in the upward migration and 0.32m/min in the downward migration, respectively. That is the rate of vertical migration was slightly higher at dusk than at dawn. Similar migration patterns were observed on different stations and under different weather conditions during the surveys in 1990.

This paper applied the ensemble model output statistics (EMOS) with truncated normal distribution, which are easy to implement postprocessing techniques, to calibrate probabilistic forecasts of wind speed that take the form of probability density functions. We also considered the alternative implementations of EMOS, which were EMOS exchangeable model and reduced EMOS model. These techniques were applied to the forecasts of wind speed over Pyeongchang area using 51 members of the Ensemble Prediction System for Global (EPSG). The performances were evaluated by rank histogram, mean absolute error, root mean square error and continuous ranked probability score. The results showed that EMOS models with truncated normal distribution performed better than the raw ensemble and ensemble mean. Especially, the reduced EMOS model exhibited better prediction skill than EMOS exchangeable model in most stations of study area.