• Journal of Environmental Impact Assessment
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• v.12 no.5
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• pp.383-393
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• 2003

IPCC(Intergovernmental Panel on Climate Change)는 향후 100년 동안 지구의 평균기온이 $1^{\circ}C$에서 $3.5^{\circ}C$ 상승할 경우, 각 기후대가 극방향으로 약 150~550km 이동할 것으로 예측하고 있으나, 과거 기후변동 연구결과들은 삼림의 이동속도를 100년간 4~200km로 추정하고 있어 식생이 기후대의 이동을 따라가지 못하여 사멸되는 지역이 발생할 것으로 예측되고 있다. 약 960km의 남북으로 긴 지형적 특성을 가진 한반도 역시 이러한 영향을 벗어나지 못할 것으로 예측되고 있어 기존의 기후변화 시나리오와 함께 삼림의 이동성을 고려한 영향연구가 요구된다. 본 연구는 IPCC의 새로운 기후변화 시나리오인 SRES 시나리오의 대기대순환모형(Global Climate Model, GCM) 결과와 AIM(Asia Integrated Model)/Impact[Korea] 모형을 이용하여 제작된 Holdridge 생물기후분류의 연구성과를 이용하여, CO2농도 배증시의 한반도지역의 자연식생 영향과 적응 가능성을 삼림의 이동성을 고려하여 평가하였다. 삼림의 이동속도를 0.25, 0.5, 1.0, 2.0(km/yr)로 변화시키며 2100년 한반도 자연식생의 기후 변화 영향을 평가한 결과, (1) 목본식물의 이동속도가 년간 1km 이상일 경우 삼림 피해가 미미하게 나타났으나 (2) 이동이 느린 0.25km/yr의 경우, 생육위험지역을 포함한 시나리오별 전체 피해규모는 A2(17.47%), A1(9.97%), B1(6.21%), B2(5.08%) 순으로 나타났으며, 삼림소멸의 경우는 A2, B2 시나리오에서 발생하며 A2 시나리오에서 한반도의 약 2.1%로 가장 크게 발생하였다. (3) 전반적인 생육위험 지역의 분포는 함흥만, 영흥만의 동해안지역에 집중되었으며, A2 시나리오의 극단적 소멸예상지역은 금오산, 가야산, 팔공산을 연결하는 지역에서 발생하는 것으로 나타났다.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.391-396
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• 2009

The percentage of those aged 60 and over is 43.5% among our country's 3,186 thousands farming population, so farm village is getting aging society rapidly. Moreover agricultural competitiveness has being weakened due to labor shortage by degradation in quality of labor configuration from elderly porson. For realisms easy workability, we developed a motor vehicle for agricultural activity. The vehicle has an automatic guidance system which could follows a track of magnetic tape on the floor for easy moving to given working position. We collected data from two guidance sensors, located on front and rear end of the vehicle and calculated displacement and angle deviation from the track. This traveling system was stably controlled with processing information deflection S, angle of deviation, D and angle velocity, Vt = $k_1D$ - $k_2S$ from two guidance sensors attached on front and rear of th motor vehicle. Also this system have been tested under various condition of $k_1$, $k_2$ for comparison on both stepped and turning routes. The results show that traveling performance is best at $k_1$=0.7, $k_2$=3.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1225-1233
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• 2008

In this paper, the 2D/3D converting algorithm is proposed. The single frame of 2D image is used fur the real-time processing of the proposed algorithm. The proposed algorithm creates a 3D image with the depth map by using the vertical position information of a object in a single frame. In order to real-time processing and improve the hardware complexity, it performs the generation of a depth map using the image sampling, the object segmentation with the luminance standardization and the boundary scan. It might be suitable to a still image and a moving image, and it can provide a good 3D effect on a image such as a long distance image, a landscape, or a panorama photo because it uses a vertical position information. The proposed algorithm can adapt a 3D effect to a image without the restrictions of the direction, velocity or scene change of an object. It has been evaluated with the visual test and the comparing to the MTD(Modified Time Difference) method using the APD(Absolute Parallax Difference).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4C
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• pp.401-410
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• 2007

In this paper, we propose water quality monitoring system using vision camera and multiple objects tracking method. The proposed system analyzes object individually using vision camera unlike monitoring system using sensor method. The system using vision camera consists of individual object segmentation part and objects tracking part based on interrelation between successive frames. For real-time processing, we make background image using non-parametric estimation and extract objects using background image. If we use non-parametric estimation, objects extraction method can reduce large amount of computation complexity, as well as extract objects more effectively. Multiple objects tracking method predicts next motion using moving direction, velocity and acceleration of individual object then carries out tracking based on the predicted motion. And we apply exception handling algorithms to improve tracking performance. From experiment results under various conditions, it shows that the proposed system can be available for real-time water quality monitoring system since it has very short processing time and correct multiple objects tracking.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.229-234
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• 2010

This paper proposed the acoustic signal processing techniques, which are applicable even in the shallow river, and will enhance the frequency resolution of the ADCP (Acoustic Doppler Current profiler). ADCP is a device that measures the velocity of a moving fluid. ADCP, in general, can be operated at ~300 Khz of center frequency due to no depth limit in the sea. However, it can hardly be used due to water depth of 30cm or shallower during the dry season in the river. Therefore, existing signal processing methods are not suitable to use in the shallow river. We are proposing an alternative acoustic signal processing method using Zoom FFT. Simulation results show that errors are reduced ${\pm}62\;cm/s$ in theory, and ${\pm}93\;cm/s$ in the experiment. The existing algorithm could not estimate the current speed at the shallow river below 30 cm, but proposed algorithm estimated the current speed that was faster than 20 cm/s at the shallow river below 30 cm.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.490-496
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• 2012

The main object of this research is to minimize the shock effects which frequently result in fatal damage in offshore wind turbine on impact of barge. The collision between offshore wind turbine and barge is generally a complex problem and it is often impractical to perform rigorous finite element analyses to include all effects and sequences during the collision. On applying the impact force of a barge to the offshore wind turbine, the maximum acceleration, internal energy, and plastic strain are calculated for each load case using the finite element method. A parametric study is conducted with the experimental data in terms of the velocity of barge, thickness of the offshore wind turbine, and thickness and Mooney-Rivlin coefficient of the rubber fender. Through the analysis proposed in this study, it is possible to determine the proper size and material properties of the rubber fender and the optimal moving conditions of barge.

• Fire Science and Engineering
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• v.22 no.4
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• pp.20-26
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• 2008

The performance of natural smoke ventilators in High-rise buildings was analyzed by investigating the stack effect depending on the wind velocities using CONTAMW tool. The results showed that the opening of smoke ventilators can influence on the stack effect in the building thus moving the position of the neutral plane toward the opened smoke ventilators. The outside wind velocities can move up the neutral plane toward the top of the building thus increasing pressure differentials at the bottom of the building. The smoke ventilators can maintain its normal performance without outside wind, however, strong outside wind can prevent natural smoke exhaust due to the infiltration of outside air at the ventilators.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.451-462
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• 2011

The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume with scaled-model and simulation when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250 m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.4
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• pp.356-363
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• 2015

Microbubbles moving in the turbulent boundary layer are visualized and investigated in the point of frictional drag reduction. The turbulent boundary layer is formed beneath the surface of the 2-D flat plate located in the tunnel test section. The microbubble generator produces mean bubble diameter of 30 – 50 μm. To capture the micro-bubbles passing through the tiny measurement area of 5.6 mm² to 200 mm², the shadowgraphy system is employed appropriately to illuminate bubbles. The velocity field of bubbles reveals that Reynolds stress is reduced in the boundary layer by microbubbles’ activity. To understand the contribution of microbubbles to the drag reduction rate more, much smaller field-of-view is required to visualize the bubble behaviors and to find the 2-D void fraction in the inner boundary layer.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.47-55
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• 2012

This paper describes the developed HILS and test equipment in order to test the performances of MMW(Millimeter-Wave) seeker which can detect and track a high speed of short-range ballistic missile and aircraft. This system is used to 141 horn antenna array, array switching, and gain and phase control algorithm to simulate various kind of targets and trajectory of high speed and maneuver moving target. In addition, it simulates not only velocity and range for these targets but also clutter and jamming environments. System configuration and implementation and the measurement results of major subsystems such as target motion simulator, simulation signal generator, high speed data aquisition unit, and central control unit are presented. These systems could verify the detection and tracking performance of MMW seeker through dynamic real-time test based on simulation flight scenario.