• 한국태양에너지학회 논문집
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• 제39권1호
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• pp.77-89
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• 2019

The solar air heater has various performances according to an obstacle installed in the air duct. Many studies on thermal performance have been conducted. But many of these studies were using a kind of rib type obstacle attached at the bottom of absorbing plate, but they are so hard to be manufactured. In this study, characteristics of the heat transfer and pressure drop in the solar air heater with various horizontal rectangular obstacles was investigated by CFD (Computational Fluid Dynamics) analysis. As a result, the heat transfer performance was improved from 1.2 to 3.32 times depending on installation conditions of rectangular obstacle. The pressure drop, however, also increased with increment of heat transfer performance from 2.8 to 180 times only by changing installation conditions of rectangular obstacle. Thus, the performance factor presenting the thermal performance enhancement on the same pressure drop was also confirmed. As a result, the highest value of 0.828 as better performance factor was obtained at the lower height of rectangular obstacle and this value has started to decrease with increment of heat transfer performance. In the end, it could be confirmed that the pressure drop was carried higher than the quantity of improvement of the heat transfer performance when the heat transfer performance was increased by change of installation conditions of rectangular obstacle. Both heat transfer enhancement and pressure drop to be required for system need to be considered before the rectangular obstacles are applied to the solar air heater.

• 산업경영시스템학회지
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• 제47권2호
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• pp.65-73
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• 2024

This paper presents a path planning optimization model for the engineering units to install obstacles in the shortest time during wartime. In a rapidly changing battlefield environment, engineering units operate various engineering obstacles to fix, bypass, and delay enemy maneuvers, and the success of the operation lies in efficiently planning the obstacle installation path in the shortest time. Existing studies have not reflected the existence of obstacle material storage that should be visited precedence before installing obstacles, and there is a problem that does not fit the reality of the operation in which the installation is continuously carried out on a regional basis. By presenting a Mixed Integrer Programming optimization model reflecting various constraints suitable for the battlefield environment, this study attempted to promote the efficient mission performance of the engineering unit during wartime.

• 한국환경과학회지
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• 제18권10호
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• pp.1115-1121
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• 2009

The purpose of this study is to estimate the impact of rainfall measurement according to the installation conditions of rain gauges: windbreak, grass mat, installation elevation or obstacle. Rain gauges were installed by the standards of Korea Meteorological Administration(KMA), and the rainfall measurement was conducted daily unit during two years(2007~2008). In conclusion, observed error of rain gauge did not affect whether windbreak was installed or not. If there is the obstacle around rain gauge, average error rate was increased about 3.3%: (2007year-2.49%, 2008year-4.10%). If rain gauge is located in a high place, average error rate was increased about 4.89%. Additionally, the observed error of rain gauge according to the wind speed has a positive correlation with obstacle and installation elevation and has a negative correlation with windbreak and has no affection with grass mat.

• 한국항공운항학회지
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• 제31권1호
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• pp.18-25
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• 2023

In recent years, UAM (Urban Air Mobility) has emerged as a solution to these urbanization problems, and many related reports and diverse prospects have been reported. UAM flights are planned to take off and land at a Vertiport located in the city center and fly along a pre-established corridor. In order for UAM to operate safely in the city center, it must ensure a safe flight path that avoids the buildings in the city center and many surrounding obstacles. Therefore, in this study, we compared and examined the installation standards of the obstacle limitation surface necessary for UAM to take off and land safely at the Vertiport. First, we analyzed the helicopter obstacle limitation surfaces in Japan and overseas, and the UAM Vertiport installation standards and obstacle limitation surface application standards recently announced at the FAA and EASA. It identified differences and similarities between heliport and Vertiport, and considered improvements to domestic helicopter obstacle limitation surfaces and criteria that could meet FAA and EASA standards.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.110-115
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• 2004

Examine merits and demerits and obstacle factor that exist to all direction of digital infratechnology that is supplied on industry whole according to development special quality of computer by development of computer and Information Technology and electricity electron information communication facility that basic impulse insulation level does not exist examined scorched earth or an interference problem factor and countermeasure of semiconductor degauss of factor and electricity electron information transmission system that is numbed or causes system down.

• 조명전기설비학회논문지
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• 제21권10호
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• pp.1-12
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• 2007

본 실험에서는 운전자의 시인성을 측정하였다. 운전자의 시인성은 전압패턴에 따라 피험자의 장애물 인식 반응시간을 측정하여 분석하였고, 남녀 성별 간의 장애물 인식 반응시간의 차이를 분석하였다. 또한 전조등의 전압변동에 의한 밝기 비율에 따라서 피험자의 장애물 인식 반응속도를 분석하였고, 전압변동이 없을 때의 장애물 인식 반응시간을 기준으로 상대적인 장애물 인식 지연시간을 분석하였다.

• 조명전기설비학회논문지
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• 제20권10호
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• pp.10-18
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• 2006

본 논문에서는 전조등의 밝기 변화가 운전자에게 어떠한 영향을 미치는지에 대하여 연구 하였다. 이러한 연구를 위하여 먼저 실내 실험실을 설계 및 구축하고 전조등의 순간적인 자기 변동과 피험자의 뇌파 측정을 위한 시스템을 제작하였다. 그리고 본 실험에 들어가기 전 예비실험을 행하여 실험 시간, 피험자 휴식 시간, 구체적 실험 순서, 전조등의 전압변화 패턴, 장애물 경로 등을 결정하였다.

• 조명전기설비학회논문지
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• 제20권9호
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• pp.45-53
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• 2006

This paper proposes a method for an effective intelligent route decision for automatic moving robots(AMR) using a 2D spatial map of a stereo camera system. In this method, information about depth and disparity map are detected in the inputting images of a parallel stereo camera. The distance between the automatic moving robot and the obstacle is detected, and a 2D spatial map is obtained from the location coordinates. Then the relative distances between the obstacle and other objects are deduced. The robot move automatically by effective and intelligent route decision using the obtained 2D spatial map. From experiments on robot driving with 240 frames of stereo images, it was found that the error ratio of the calculated distance to the measured distance between objects was very low, 1.52[%] on average.

• International Journal of Railway
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• 제3권3호
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• pp.106-112
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• 2010

Accidents at level crossing have large portion on train accidents, and causes economical loss by train delay and operational interruption. Various safety equipments are employed to reduce the accident at level crossing, but existing warning device, and crossing barrier are simple train-oriented protection equipments. In this paper, intelligent railway level crossing system is proposed to prevent and reduce accidents. For train driver's prompt action, image of level crossing and obstacle warning message are continuously provided to train driver through wireless communication in level crossing control zone. Obstacle warning messages, which are extracted by computer vision processing of captured image at level crossing, are recognized by train driver through message color, flickering and warning sound. It helps train driver to decide how to take an action. Meanwhile, for vehicle driver's attention, location and speed of approaching train are given to roadside equipments. We identified the effect of proposed system through test installation at Sea train and Airport level crossing of Yeong-dong line.

• 해양환경안전학회지
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• 제28권2호
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• pp.244-253
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• 2022

최근 해상풍력발전단지 등의 구조물 설치를 추진하는 사업이 증가하고 있는 추세이며, 이러한 해상장해물의 설치는 인근 해역을 통항하는 선박에게 영향을 미칠 수 있다. 이에 본 연구는 통항로 내 장해물에 따라 통항하는 선박에게 주는 위험도를 정량적으로 평가하는 것이 목적이다. 이를 위해 위험도에 영향을 미치는 파라미터를 선정하고, 파라미터를 기반으로 시나리오를 설정하였다. 본 연구는 위험도 평가 모델인 ES 모델을 통해 시나리오 평가를 실시하였으며, 장해물의 크기가 커지고, 장해물과의 이격거리가 커지고, 통항 속력이 느리고, 통항량이 증가할수록 위험 비율이 높아짐을 확인하였다. 또한, 교통흐름 방향이 지정된 경우에 일반적인 교통흐름에 비해 낮은 위험 비율을 보임을 파악하였다. 본 연구는 수행된 시나리오 결과를 기반으로 일반화 모형을 제시하여 다대포 해상풍력발전단지에 적용하였으며, 일반화 모형을 통해 대략적인 위험 비율을 추정하는 것이 가능함을 나타냈다. 본 연구에서 제시된 일반화 모형은 해상장해물 설치에 있어 사전 참고자료로 활용될 수 있을 것으로 판단된다.