• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.514-523
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• 2004

In this paper, a new intelligent moving target tracking and surveillance system basing on the pan/tilt-embedded stereo camera system is suggested and implemented. In the proposed system, once the face area of a target is detected from the input stereo image by using a YCbCr color model and then, using this data as well as the geometric information of the tracking system, the distance and 3D information of the target are effectively extracted in real-time. Basing on these extracted data the pan/tilted-embedded stereo camera system is adaptively controlled and as a result, the proposed system can track the target adaptively under the various circumstance of the target. From some experiments using 80 frames of the test input stereo image, it is analyzed that standard deviation of the position displacement of the target in the horizontal and vertical directions after tracking is kept to be very low value of 1.82, 1.11, and error ratio between the measured and computed 3D coordinate values of the target is also kept to be very low value of 0.5% on average. From these good experimental results a possibility of implementing a new real-time intelligent stereo target tracking and surveillance system using the proposed scheme is finally suggested.

• Fire Science and Engineering
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• v.22 no.1
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• pp.16-23
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• 2008

In this research, the visualization experiment for a scaling tunnel was conducted to establish the optimum fire protection system in tunnel fires. In order to find the optimal operating condition of jet fan with the fire, the characteristics of smoke propagation was considered to find the optimal operating condition of jet fan at the time of tunnel fire, the concentration of smoke was measured experimentally for various jet fan position and it's operating condition. As a result, when jet fan in the vicinity of fire operates at the upstream, the back-layering of the smoke should be considered with separation distance from the fire source. The distance between the jet fan and the fire should be longer than 50 m. On the other hand, when the vicinity jet fan operates at the downstream, the back-layering of smoke does not occur, but stratification is not maintained because the smoke dispersion occurs at the downstream due to the operation of the jet fan.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.501-511
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• 2018

As a result of the recent revision of the 'Guideline for Installation and Management of Fire Prevention Facility in Road Tunnels', the thermal buoyancy has to be taken into account when calculating the capacity of jet fans for smoke control in tunnel fires. However, there is no detailed methodologies for considering thermal buoyancy, so further study is needed. In this study, the thermal buoyancy in the tunnel is calculated by 3-D numerical simulation to consider the thermal buoyancy in case of fire in tunnels, and the relationship between heat buoyancy and vehicle drag, And the method of calculating the capacity of the jet fan for smoke control in tunnels. According to the analysis results, heat buoyancy acts as a resistance force in the case of a down-slope tunnel, and the pressure rise of jet fan for smoke control is not simply determined by the value of heat buoyancy at the entrance of the tunnel and the value of the vehicle drag at the exit. And it is analyzed that it is necessary to carry out a comprehensive review according to the location of the fire vehicle in tunnels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.527-535
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• 2017

Heat management is one of the most critical issues in Polymer Electrolyte Membrane Fuel Cells (PEMFCs) installed inside the fuel cell power pack of a fuel cell battery hybrid UPS. If the heat generated by the chemical reaction in the fuel cell is not rapidly removed, the durability and performance of the fuel cell may be affected, which may shorten its lifetime. Therefore, the objective of this study is to select and propose a proper cooling method for the fuel cells used in the fuel cell power pack of a UPS. In order to find the most appropriate cooling method, the various design factors affecting the cooling performance were studied. The numerical analysis was performed by a commercial program, i.e., COMSOL Multiphysics. Firstly, the surface temperature of the 1 kW class fuel cell stack with the cooling fans placed at the top was compared with the one with the cooling fans placed at the bottom. Various rotation speeds of the cooling fan, viz. 2,500, 3,000, 3,500, and 4,000 RPM, were tested to determine the proper cooling fan speed. In addition, the influence of the inhaled air flow rate was investigated by changing the porous area of the grille, which is the entrance of the air flowing from the outside to the inside of the power pack. As a result, it was found that for the operating conditions of the 1 kW class PEMFC to be acceptable, the cooling fan was required to have a minimum rotating speed of 3500 RPM to maintain the fuel cell surface temperature within an acceptable range. The results of this study can be effectively applied to the development of thermal management technology for the fuel cells inside the fuel cell power pack of a UPS.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.641-644
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• 1999

스테레오 물체 추적기는 좌. 우측 카메라의 스테레오 입력 영상에서 이동 물체의 주시각을 제어하면서 자동으로 추적 물체가 항상 영상의 중앙에 위치하도록 제어해야 한다. 본 논문에서는 복잡한 배경이 존재하고 카메라가 움직이는 경우 스테레오 물체 추적을 위한 방법으로 블록 정합 알고리즘(BMA)으로 추적 물체와 배경을 분리하고, JTC를 이용해 주시각 및 팬/틸트 제어 값을 구하여 좌, 우측 카메라를 제어하는 스테레오 자동 물체 추적 시스템을 제시하였다. 추적결과 배경잡음에 상관없이 적응적으로 작용하여 정확히 이동 물체의 위치를 스테레오로 추적할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.264-264
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• 2023

물순환 과정에서의 증발산은 장기적인 관점에서의 수자원 계획 수립 시 중요한 요소이다. 증발산은 기온, 상대습도, 일사량 등 기상학적 인자뿐만 아니라 증발표면, 식생분포 등 다양한 인자의 복합작용에 의해 일어나므로, 유역 단위에서 발생한 실제증발산(Actual evapotranspiration, AET)을 측정하기에는 기술적인 한계가 존재한다. 그러나 증발산 보완관계(Complementary relationship of evapotranspiration, CRE) 가설을 활용하면, 수문요소의 상호작용을 고려한 모델링을 거치지 않고도, 비교적 간단하게 AET를 추정할 수 있다. 본 연구는 증발산 관측자료를 기반으로 유역 단위에서의 CRE를 검증하고자 하며, 플럭스 타워 등 다양한 관측장비가 설치되어 있는 용담댐 시험유역을 대상유역으로 선정하였다. 용담댐 유역 내 산지에 위치한 덕유산 플럭스 타워에서 측정된 증발산을 AET로 보았으며, 유역 인근에 위치한 전주 기상관측소에서 측정되는 팬 증발량(E_pan)을 잠재증발산량(Potential evapotranspiration, PET)으로 보았다. E_pan 계측시, 증발팬의 가열 등 주변환경 변화로 인해 과다하게 추정되는 값을 보완하기 위해 FAO Penman-Monteith 식을 활용해 팬 증발량 보정계수(Coefficient of pan evaporation, k_p)를 산정하여 적용하였다. 습윤증발산량(Wet evapotranspiration, WET)은 대기가 완전히 포화되었을 때 발생하는 증발산량으로, 댐 수표면에서 계측되는 수면증발량을 WET로 보았다. CRE 검증을 위해 AET와 PET를 각각 WET로 나누어 AET+와 PET+로 무차원화하였으며, 습윤지수(Moisture Index, MI)는 AET를 PET로 나누어 산정하였다. CRE 가설은 MI에 따른 AET+와 PET+가 서로 보완관계를 갖는다는 것인데, 용담댐 유역의 관측자료를 활용하여 CRE를 검증한 결과 AET+와 PET+ 간의 비대칭계수(b)가 1.23인 것으로 나타났다. 이 때의 평균제곱오차(MSE)는 0.599, 결정계수(R₂)는 0.631로 나타나 CRE의 b가 적합하게 추정된 것으로 판단된다. 본 연구결과와 같이 검증된 CRE를 통해 증발산 관측지점이 없거나, 조밀하지 않은 유역의 AET를 간접추정할 수 있으며, 이를 활용해 보다 정확한 댐의 장기유출 모의와 용수공급계획 수립에 도움을 줄 수 있을 것으로 기대된다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.630-636
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• 2008

1000MW급 증설과 관련하여 발전소 주변지역으로부터 민원이 제기된 3000MW급 화력발전소는 넓은 평지에 위치하여 발전소의 영향이 그대로 주변지역에 전달되는 상태임에도 일상 소음레벨이 환경 기준치를 만족하는 상태였으나 향후 증설에 따른 소음도 증가에 대비하여 소음영향을 예측하고 저감 대책을 검토하였다. 대형 화력발전소의 옥외소음원은 Booster fan, I.D.fan, 주변압기, 대형 철탑, 해수순환수 펌프 전동기, 증기방출관 등이 있다. 대상 주거지역의 경우는 대형팬에 의한 지향성이 크게 나타났다. 따라서, 발전소가 주변지역에 주는 소음별 기여도를 평가하고 영향이 큰 대형팬에 대한 대책으로써 기기주변에 방음벽을 설치하는 방안과 함께 소음원의 크기를 저감시킬 수 있는 소음기 대책을 추천하여 증설 예정호기를 비롯한 기존 호기중 주거지역에 영향이 큰 3000MW에 대하여 수립함으로써 소음저감 목표치를 달성하는 결과를 도출하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.1
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• pp.14-22
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• 1997

The position of propeller fan from duct inlet is one of basic parameters for the design of propeller fan. To investigate the effect of its position on fan characteristics, the inlet flow fields and relative flow angles were measured by a 5-hole pitot tube. The experimental results indicate that the ratio of radial flow introduced from propeller circumference to total inlet flow increases with the increase of propeller distance from duct inlet. When fan operates without duct, the total flow rate and the radial flow ratio are higher than those of any other positions of propeller relative to duct inlet. The radial flow ratio decreases as a flow coefficient and the propeller distance decrease. Therefore the front flow fields can be adjusted in some extent by varying the propeller distance according to a fan loading. The inlet flow angles are decreasing a little as a rotational speed and the propeller distance decrease. In the present case it was judged that the deviation angle of outlet flow became negative owing to a flow separation near a trailing edge.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.2
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• pp.107-116
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• 2012

The experiment was performed to analyze the intersectional ventilation efficiency by intersection structure and Jet Fan in network-form road tunnel. For this, the size of real road tunnel was reduced by 1/45. To apply traffic inertia force when driving, blower fan was used to form an airflow in model tunnel and the intersectional efficiency was also investigated by measuring the speed at local point of the tunnel. To improve the reduction of ventilation caused by the structure character, Jet Fan was installed to optimize ventilation efficiency in tunnel.

• Journal of IKEEE
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• v.25 no.2
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• pp.330-336
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• 2021

A typical way to reduce the number of hardware redundancy configurations is to implement them as analytical techniques for detecting, identifying and accepting failures with micro-controller. In this paper, one of the analytical techniques, the fault detection filter, is applied to aircraft turbofan engine system. The fault detection filter is a special type of observer that has the advantage of being able to determine the location of failures by maintaining a constant direction in the output space in the event of a particular failure. We present a single input/output dynamic system modeling of air turbine system in turbofan engine, a fault detection filter design, and simulation results applying it. Simulation results show that fault detection can be effectively applied as a sensitivity effect to the directionality of the detection filter.