• 대한공간정보학회지
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• 제17권4호
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• pp.61-66
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• 2009

본 연구는 넓은 지역의 DEM 생성 시 하드웨어 성능에 따라 자료를 부분적으로 처리해야 하는 불편을 개선하고 DEM의 정밀도를 개선하는 것에 그 목적이 있다. 본 연구에서 개발된 DEM Generator 프로그램은 대용량 LiDAR 자료, 수치지형도 자료에 스트리밍 방식을 적용하여 인덱싱 및 델로니 삼각망 생성을 수행하고, Natural Neighborhood 또는 TIN 보간법을 적용한 가상 파일을 생성하여 특정한 해상도로 대규모 지역의 DEM 및 음영기 복도를 효율적으로 생성하도록 설계되었다. 최종적으로 생성된 DEM 및 음영기복도는 GeoTIFF 포맷으로 제공된다. DEM Generator 프로그램은 GIS, 기상, 환경 분석 등 넓은 지역의 DEM 생성이 필요한 분야에서 기존의 부분적인 DEM 생성 및 인접 처리 과정에 의해 발생했던 시간적 경제적 손실을 절감시킬 수 있을 것으로 판단되며, 추가적인 인접 및 수정 작업이 불필요하여 DEM의 정밀도를 높일 수 있을 것으로 판단된다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2013년도 임시총회 및 하계학술연구발표회
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• pp.19-20
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• 2013

Thermoelectic properties of the typical thermoelectric host materials, the tellurides and selenides, are known to be noticeably changed by their volume change due to the strain [1]. In the bismuth telluride ($Bi_2Te_3$) crystal, a substitution of rare-earth element by replacing one of the Bi atoms may cause the change of the lattice parameters while remaining the rhombohedral structure of the host material. Using the first-principles approach by the precise full potential linearized augmented plane wave (FLAPW) method [2], we investigated the Ce substitution effect on the thermoelectric transport coefficients for the bismuth telluride, employing Boltzmann's equation in a constant relaxation-time approach fed with the FLAPW wave-functions within the rigid band approximation. Depending on the real process of re-arrangement of atoms in the cell to reach the equilibrium state, $CeBiTe_3$ was found to manifest a metal or a narrow bandgap semiconductor. This feature along with the strong correlation effect originated by the 4f states of Ce affect significantly on the thermoelectric properties. We showed that the position of the strongly localized f-states in energy scale (Fig. 1, f-states are shaded) was found to alter critically the transport properties in this material suggesting an opportunity to improve the thermoelectric efficiency by tuning the external strain which may changing the location of the f-sates.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.293-298
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• 2011

The most widely used method to form an electrode in industrial solar cells are screen printing. Screen printing is characterized by a relatively simple and well-known production sequence with high throughput rates. However the method is difficult to implement a fine line width of high-efficiency solar cells can not be made. The open circuit voltage(Voc) and the short circuit current density(Jsc) and fill factor(FF) need to be further improved to increase the efficiency of silicon solar cells. In this study, gravure offset printing method using the multicrystalline-silicon solar cells were fabricated. Gravure off-set printing method which can print the fine line width of finger electrode can have the ability reduce the shaded area and increase the Jsc. Moreover it can make a high aspect ratio thereby series resistance is reduced and FF is increased. Approximately $50{\mu}m$ line width with $35{\mu}m$ height was achieved. The efficiency of gravure off set was 0.7% higher compare to that of scree printing method.

• 한국태양에너지학회 논문집
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• 제27권4호
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• pp.137-146
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• 2007

This study is about the passive cooling effects of three outdoor solar shading facilities as trees, pergola with wistaria vine and membrane shading structure, which are expected to provide cool spots in the summer. Field observations of measuring thermal environment of selected facilities is executed. Thermal environment measuring was categorized as short wave radiation, long wave radiation, net radiation, globe temperature, surface temperature measured by infrared camera. Heat transfer mechanism is analyzed with overall data from field measurement. Results from this study are as below; 1) Radiation balance measured on shaded surface under membrane shading structure was 17%($86W/m^2$) of the unshaded surface radiation balance($511W/m^2$). 2) Surface temperature comparison between vegetation and membrane of the shading structure is performed at 3 o'clock in the afternoon. Surface temperature of vegetation was same as air temperature and that of membrane was $5^{\circ}C$ higher than air temperature. Vegetation transpiration is considered as the causing factor which make those differences. 3) Results from this study could be used as fundamental data for reducing heat island phenomena and continuos research on this subject would be needed.

• Journal of Astronomy and Space Sciences
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• 제35권1호
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• pp.47-54
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• 2018

Moon mineralogy mapper ($M^3$)'s work proved that the moon is not completely dry but has some hydroxyl/water. $M^{3{\prime}}s$ data confirmed that the amount of hydroxyl on the lunar surface is inversely related to the measured signal brightness, suggesting the lunar surface is sensitive to temperature by solar insolation. We tested the effect of solar insolation on the local distribution of hydroxyl by using $M^3$ data, and we found that most craters had more hydroxyl in shade areas than in sunlit areas. This means that the local distribution of hydroxyl is absolutely influenced by the amount of sunshine. We investigated the factors affecting differences in hydroxyl; we found that the higher the latitude, the larger the difference during daytime. We also measured the pyroxene content and found that pyroxene affects the amount of hydroxyl, but it does not affect the difference in hydroxyl between sunlit and shaded areas. Therefore, we confirmed that solar insolation plays a significant role in the local distribution of hydroxyl, regardless of surface composition.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.769-780
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• 2018

This paper presents an analysis of the power gain under partial shading conditions (PSC) when the partial shade loss is being compensated in photovoltaic(PV) system. To analyze the power gain, our study divides the mismatch loss into partial shade loss and operating point loss. Partial shade loss is defined as the power difference between a normal string and a partially shaded string at the maximum power point (MPP). Operating point loss is defined as the power loss due to the operating point shift while following the MPP of the PV array. Partial shading in a PV system affects the maximum power point tracking (MPPT) control by creating multiple MPPs, which causes mismatch losses. Several MPPT algorithms have been suggested to solve the multiple MPP problems. Among these, mismatch compensation algorithms require additional power to compensate for the mismatch loss; however, these algorithms do not consider the gain or loss between the input power required for compensation and the increased output power obtained after compensation. This paper analyzes the power gain resulting from the partial shade loss compensation under PSC, using the V-P curve of the PV system, and verifies that power gain existence by simulation and experiment.

• 한국컴퓨터정보학회논문지
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• 제4권3호
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• pp.8-12
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• 1999

에지검출방법은 영상내의 객체를 인식하거나 특정부분을 추적하는 등의 유일한 방법은 아니지만 컴퓨터비젼 분야의 많은 응용에서 매우 중요한 요소들 중의 하나이다. 만약, 에지검출이 신속하고 정확히 이루어진다면 가장 효율적인 방법이 될 수 있다. 지금까지 제안되어 왔던 많은 알고리즘들은 주로 명도영상에 적용되어 오고 있다. 그러나, 명도정보만으로 에지를 검출하는데는 많은 한계점을 가지고 있어 컬러 정보를 이용하려는 연구가 수행되고 있다. 따라서, 본 논문에서는 컬러 정보를 이용한 에지검출 알고리즘을 제안하고 기존의 방법들 중에 많이 사용되고 있는 알고리즘을 구현하고 비교하였다. 실험결과 본 논문에서 제안된 알고리즘은 미세한 부분들과 그림자부분에서 보다 우수한 성능을 보였다.

• KIEAE Journal
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• 제13권3호
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• pp.97-104
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• 2013

This proposed simulation-based design study is based on the design of residential high-rise buildings in South-Korea. the purpose of this study is to evaluate the amount of daylighting performance passing through building glazing according to sky conditions, orientation of windows and each space of Apartment buildings. The clear sky includes sunshine and is intense and brighter at the horizon than at the zenith, except in the area around the sun. Daylight received within a building is directly dependent upon the sun's position and the atmospheric conditions. Orientation of the building generally used to refer to solar orientation which is the siting of building with respect to solar access. Although any building will have different orientations for its different sides, the orientation can refer to a particular room, or to the most important facade of the building. north-facing windows receive twice the winter sun than east and west facing windows, allowing light and warmth into the home. They can be easily shaded from the high summer sun to help keep the house cool. Ideally, the glazing area should be between 10-25% of the floor area of the room. This paper was calculated by a Desktop Radiance program. The space dimensions were based on a unit module of real constructed apartment having divided into five sections such as living room, room1, room2, room3 and kitchen.

• 한국위성정보통신학회논문지
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• 제8권2호
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• pp.22-28
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• 2013

In this paper, new LBS (location based service) are proposed using conventional DMB (digital multimedia/mobile broadcasting) system. LBS applications are proposed that can be suitable for the subway and ground transportation based on S-DMB (satellite-DMB) and T-DMB (terrestrial-DMB) respectively. In the shaded area such as subway, the broadcasting signal transmitted from the satellite of S-DMB system should be retransmitted by the earth repeater called the gap filler and each gap filler has its own identification value called the gap filler ID which introduces the area in which the gap filler was installed. Therefore, the LBS can be implemented by using the gap filler ID of S-DMB on the subway in which the GPS (global positioning system) can't be received. Unlike the LBS on the subway, the combination of T-DMB and DGPS (differential GPS) will be introduced as a way for ground transportation. Generally, DGPS has been designed to compensate the position value calculated from the GPS signal so that positioning error of about 1 meter can be obtained by using DGPS information. T-DMB system transmitting DGPS signal will be expected to be commercial in Korea and, if using DGPS information transmitted through T-DMB network, LBS with more precise positioning than GPS alone can be implemented in the ground vehicles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.222-223
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• 2007

Though there are many causes for the maximum output power reduction, the short-term problem is hot-spot effect by sun shading. To prevent this, normally PV maker uses bypass diode. In here, we tried to check the how bypass diodes works by varying sun shading portion on solar. In case of absence of bypass, the sun shading effect increases the series resistance and that promotes the reduction of maximum power and degradation of PV modules. Bypass diode worked normally when 60% of solar cell was shaded and the measured maximum output power was lower than that of theoretical one. The further analysis is needed.