Numerical analysis has been carried out to investigate seawater flow field characteristics with various current directions near the manganese nodule mining device. Seawater flow near the collecting device is largely influenced by the sea current direction, especially along the downstream of the rear system. Predicted flow velocity distributions are analyzed with turbulent kinetic energy and drag force. There is big flow field variation when the direction angle between the mining device and seawater current flow approaches to 30°~ 120°, and flow velocity along the rear region of 60° becomes faster than 180°. Averaged turbulent kinetic energy at 180° also becomes low, about 57% higher at 60°. These results from the study can be applicable to the optimum design of manganese nodule collecting system in the deep seawater flow.

Seawater flow characteristics around deep-sea sediment resuspension system was analyzed using CFD simulation. Seawater flow is influenced by migration velocity of DSSRS and the resuspension system with disturbance device. Especially complicated flow field is generated with discharged flow in the vertical direction, and there is large variation of seawater velocity near the system with vortex flow. Turbulent kinetic energy near the system increases 2～6 times, and its variation is also affected by the operation condition of the disturbance device. The results of this study are expected to be useful in evaluating the environmental effects of the suspended solid matters which are generated in the deep sea sediment disturbance process.

Numerical analysis was performed to analysis the structural characteristics of the head device in the road mower system. The head device connects mower system with the boom of the special vehicle. The system with various road surface conditions is subjected to continuous vibration and repeated load. Especially, the maximum equivalent stress occurs in the pillar of the head device, and the maximum equivalent strain also occurs in the fixed plate that supports the mower system. Fatigue analysis results show that the upper end of the pillar is very vulnerable. This analysis results can be used as basic data for optimal road mower head system design.

In this study, temperature variation characteristics in a flat plate with sheath heater are investigated through experiment and numerical analysis. ANSYS fluent is used to calculate the temperature distribution in the heating plate system. Transient condition is applied to observe temperature variation with the sheath heater operation, and thermal resistance on the contacted surfaces is also considered. Experimental data agree well with numerical results obtained for heat generation rate from sheath heater, Local temperature variation on the surface of flat plate is also predicted through this simulation. There is large temperature variation in the air surrounded flat plate, especially at the top of flat plate with natural convective heat transfer. These results will be helpful in optimal design for various systems equipped with sheath heater.

Numerical analysis was carried out to investigate the variation of stress and strain characteristics for the rail device in stone board cutting system. The maximum equivalent stress and strain from the vertical load acting on the device decrease as the load moves forward. Also, the maximum equivalent stress appears near the end of left, and the equivalent force of right rail device was about 1.8 times higher than that of left rail device. The variation of stress and strain distributions was remarkable at the edge of the device, and it has a strong influence on the bottom and column. These results can be applicable to optimal design of the stone board cutting device for the system safety.

CFD(Computational Fluid Dynamics) analysis was carried out to analysis the air flow characteristics of vertical axis wind turbine system with accelerating device. Geometric arc angle of the accelerating device affects the air flow characteristics in the turbine with the effect of Coanda generated from the curved surface. Air velocity distributions with the device angle variation are compared. Flow velocity increases with the device length, and the accelerating device plays a key role in decreasing the air velocity in the wake flow region. Maximum air velocity variation becomes reduced with the accelerating device, and it is largely affected by the arc angle. These results are expected to be utilized in various ways to determine the shape of accelerating device for wind power generation system.

The characteristics of temperature variation for laser diode welding system have been analyzed with numerical investigation. The laser diode is assembled with a cap and stem by projection welding. Resistance heat, in this process, is generated by electric current at the contact surface between cap and stem within a very short time. Temperature variation of laser diode is largely affected by the welding time and the heat generated from the surface. Maximum temperature of each component in the laser diode should be lower than the melting point except for cap and stem in order to prevent welding defect. Temperature distribution of each component in the laser diode is also affected by thermal conduction mechanism. Welding defect near the insulator occurs when the resistance heat is high. Appropriate resistance heat supply to the laser diode was about 400W. The results from this study could be applicable for optimal design of laser diode welding system.

The study measured the volatile organic compounds consistency of the child tympanitis patient family. Benzene, the result which analyzes toluene, ethylbenzene, xylene and TVOC consistency, case of personal exposure they were 0.518 μg/m3, 0.909 μg/m3, 1.299 μg/m3, 0.960 μg/m3 and 273.718 μg/m3 respectively, case it appeared with benzene the interior 0.539 μg/m3 and toluene 1.433 μg/m3 and ethylbenzene 1.253 μg/m3 and xylene 1.899 μg/m3 and TVOC 262.132 μg/m3. The consistency of the outdoor benzene, toluene, ethylbenzene, xylene and TVOC appeared respectively with 0.512 μg/m3, 0.474 μg/m3, 1.177 μg/m3, 0.862 μg/m3 and 22.306 μg/m3. Personal exposure, the residential interior, interrelationship analytical result Benzene of outdoor consistency and Ethyl benzene, Xylene and TVOC personal exposures with the interior and outdoor consistency showed the interrelationship which considers(p < 0.01). VOCs consistency which it follows in residential type the detached home > the multi generation house > the consistency price came out with the apartment order, VOCs consistency which it follows construction year possibility the year valence which is built 4 years at once rises the consistency appeared more highly the case where the case is above 4 years than.

In this study, center marking process is numerically analyzed to investigate the characteristics of deformation of aluminium alloy bracket by the pin load. The proper size of groove which are required for marking system and the pressure of cylinder are predicted through the analyse of stress and strain fields of the plate. The results of this study show that von Mises stress is a maximum when the maximum of reaction force.

In this study, temperature variation characteristics in the stone board cutting device with sheath heater were analyzed through numerical investigation. Four 2kW sheath heaters whose length and diameter are 1800mm, 11mm are installed, and the initial temperature is -5℃. Also Transient condition is used for temperature variations with the operating time of sheath heater. From the analysis, transient temperature variations of cutting device after operating the sheath heater were predicted. Temperature variations were predicted that mainly appears in part contacted with the sheath heater. The result will be helpful in optimal design for various system equipped with sheath heater.

Numerical analysis has been carried out to investigate particles behavior characteristics during the grinding process in the air. Grinding particles behavior is largely affected by many parameters such as operating conditions and process room geometry. Transient particle motion in the air is predicted, and the effects of particle diameter and device rotational speed on the behavior characteristics were compared. When particle size is not large enough, they shortly moves in a tangential direction of the device rotation, and then are mostly influenced by the air flow in the room. These results could be applicable to the optimal design of the grinding process room.

Numerical modeling has been carried out to analyze thermal characteristics for laser diode welding machine. Laser diode welding machine performance is largely affected by the applied current and welding period. Unsteady thermal characteristics near the laser diode welding cap has been analyzed, and most simulations were performed after applying electrical current for the duration from 0.1 to 0.5 second. Those results from this study could be applicable to the design of optimal operating condition for the laser diode welding machine system.

우리 나라 남서부에 위치한 변산반도내에 자생하고 있는 꽝꽝나무군락지의 천이에 관한 장기적인 모니터링과 보전관리를 위한 기초자료를 제공하기 위하여 서식환경 및 생육실태 등을 조사 분석한 결과를 요약하면 다음과 같다. 꽝꽝나무군락의 분포면적은 270m2로성목 123그루와 치수 약 170그루가 자라고 있다. 꽝꽝나무군락지 내부에는 총 21과 31속 30종 6변종 1품종(총 37분류군)의 관속식물이 서식하고 있다. 꽝꽝나무 성목의 평균 수고는 1.0m, 평균 수관폭은 동서 방향 112.3cm 남북 방향 91.3cm이었다. 꽝꽝나무의 평균 엽길이는 10.2mm, 평균 엽폭은 6.9mm, 평균 엽병길이는 1.7mm 평균엽면적은 0.47 cm2로서 좀꽝꽝나무로 표기하는 것이 타당하다고 사료된다. 꽝꽝나무 성목은 모두 개화하였으며 꽃은 모두 암꽃이었다.

온라인 게임 산업의 성장과 함께 해킹 툴의 사용은 날로 증가하고 있다. 해킹 툴은 프로그래밍 지식이 없는 유저들이 해킹과 동일한 기능을 사용할 수 있도록 해주기 때문에 온라인 게임서비스에 있어 많은 문제점을 야기한다. 특히, P2P 네트워크 기반의 FPS 게임은 해킹에 대한 취약성을 가지고 있다. 본 논문은 인도네시아 Point Blank의 사례를 통해 FPS 게임의 치팅 유형을 분석하고, 게임 업체들이 해킹에 대한 효과적인 대처 능력을 갖출 수 있도록 대응방안의 우선순위를 제시하였다.