• 전기의세계
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• 제23권2호
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• pp.39-45
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• 1974

An analysis is developed for the torque characteristics of single-phase induction motors having variable shaded-pole angles. The machanism have two sets of stator windings which one set of stator fed from single-phase sources and other shorted by inserted external impedances. Thus, by phisically rotating one set of stator windings with respect to the other, the only shaded-kpole effect torque performance of a single- phase induction machine and its performance prediction to be expected of the optimum shaded-pole angle can be achieved.

• 인간식물환경학회지
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• 제23권3호
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• pp.333-345
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• 2020

Background and objective: The purpose of this study was to provide basic data on trees that can be used for planting design and construction for permanently shaded areas by grasping the growth status of trees according to the daylight conditions of the outdoor spaces of apartment complexes. Methods: On the recently completed apartment complexes, daylight conditions were analyzed by using daylight simulations utilizing Solar Access Analysis of Ecotect Analysis. With a criteria for assessment of tree condition, the defect rate of trees planted in permanently shaded areas and green spaces with good daylight conditions was analyzed to suggest trees applicable to permanently shaded areas. The first tree survey was conducted from November 18, 2019 to February 15, 2020, focusing on trees planted in permanently shaded areas, and the second tree survey of all the trees planted on the study sites including permanently shaded areas was conducted from March 16 to March 30, 2020. Results: Evergreen trees which are classified as shade intolerant trees including Pinus densiflora, Thuja occidentalis, and Abies holophylla showed a higher defect rate of trees among the trees planted in permanently shaded areas. Taxus cuspidata, Zelkova serrata, Cornus kousa, Chionanthus retusus and Acer palmatum which are classified as shade tolerant trees and shade moderate tolerance trees seemed to be able to be used in the plant design of permanently shaded areas in apartment complexes because the trees showed good growth and a low tree defect rate. In addition, although it was excluded from the analysis due to a small number of samples, Sorbus commixta and Prunus cerasifera var. atropurpurea also can be used for planting in permanently shaded areas. Conclusion: The daylight simulation technique used to analyze permanent shaded areas in this study can be used as an analysis tool considering the daylight environment at the stages of design and construction, and additional research will be required to analyze tree growth according to daylight conditions through data accumulation and monitoring by managing records throughout the entire life cycle of trees in the process of planting and maintenance.

• 한국지리정보학회지
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• 제9권1호
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• pp.127-136
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• 2006

수치지형모형을 시각적으로 분석하는데 있어 음영기복을 사용하고 있지만 지형의 음영 표현만을 생각하는 경우가 있어 정확한 그림자 범위를 확인하지 않고 있다. 본 연구는 GIS의 지형 표현에 사용되는 음영기복 기능을 렌더링과 비교하여 지형의 그림자 특성을 파악함으로써 각각 나타나는 수치지형모형상의 표현 차이를 분석하였다. 도로가 있는 지형으로 실험 대상지역을 선정하여 불규칙삼각망의 수치지형모형을 생성한 후 09시와 15시의 시간대별 태양의 방위각 및 고도에 따른 음영기복과 렌더링 기법을 적용하였다. 그 결과 음영기복은 태양의 광선을 받는 지형지물의 뒷부분만 어두운 상태로 나타났고, 렌더링을 통하여 투영된 그림자가 생성됨을 알 수 있었다. 이 상호 비교를 통해 음영기복을 이해할 수 있는 자료로 제시할 수 있으며, 렌더링 기법은 지형지물의 일조 분석 등에 효과적으로 사용될 수 있을 것으로 기대된다.

• 한국광학회지
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• 제10권6호
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• pp.443-447
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• 1999

본 연구에서는 shaded spodizer가 광학 디스크 시스템의 재생신호에 미치는 영향을 조사하기 위하여 동의 중앙에서 가장자리로 갈수록 진폭이 단조 감소하는 shaded spodizer와 진폭이 단조 증가하는 shaded spodizer를 스칼라 회절 이론을 사용하여 고려하였다. 또한 bump 형태 변화에 따른 재생 신호의 변화를 조사하기 위하여, 원통형, 준원추형, 그리고 원추형 bump를 고려하였으며, 이때 bump의 높이는 $\lambda/4$로서, 위상 높이가 $\pi$가 되도록 하였다. 동의 중앙에서 가장 자리로 갈수록 진폭이 단조 감소하는 shaded spodizer의 경우에는 bump 반경이 증가함에 따라 재생 신호가 증가하여 극대값을 가진 후 감소하는 경향이 나타났으며, 진폭이 단조 증가하는 shaded spodizer의 경우에는 bump 반경이 작은 영역과 큰 영역에서 극대값을 갖는 특성을 나타냈다. 도한 구면수차를 0.5λ 포함하는 광학 디스크 시스템의 경우 진폭이 단조 감소하는 shaded spodizer의 최대 재생 신호가 spodizer를 사용하지 않은 경우의 최대 재생 신호보다 크게 나타났다.

• 한국환경복원기술학회지
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• 제21권6호
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• pp.1-13
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• 2018

Mapping radiation heat flux of urban area is essential for urban design and landscape planning. Because controlling urban geometry and generating green space are important urban design strategies for reducing urban heat, urban planner and designer need to recognize the micro urban heat distribution for adequate urban planning. This study suggests a new methodology for mapping urban radiation heat flux in a micro scale considering buildings and trees' shade. For doing that, firstly, we calculate net radiation for each urban surfaces (building, road (not shaded, building shaded, tree shaded), ground (not shaded, building shaded, tree shaded), tree (not shaded, building shaded)). Then, by multiplying the area ratio of surfaces to the net radiation, we can obtain the radiation heat flux in micro-scale. The estimated net radiation results were found to be robust with a $R^2$ of 90%, which indicates a strong explanatory power of the model. The radiation heat flux map for 12h $17^{th}$ August explains that areas under the building and tree have lower net radiation heat flux, indicating that shading is a good strategy for reducing incident radiation. This method can be used for developing thermal friendly urban plan.

• 농업과학연구
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• 제39권1호
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• pp.35-41
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• 2012

This research was conducted to investigate the influence of organic bed soil substrates on growth and yield of organically grown ginseng transplantation in a shaded plastic houses. The pH and EC of the substrates used for this study were 5.93-6.78 and 0.03-0.15 dS/m, respectively. The concentrations of NH4-N and $NO_3$-N were 14.01-68.63 mg/L, 5.60-58.83 mg/L respectively. and the average quantum in the shaded plastic houses was 11-15% of natural light. The maximum temperature in the shaded plastic houses is higher ($3-7^{\circ}C$) than that of outside open field from the last part of April to early in August. Emergence date of ginseng was on March 21 in the mongolian type shaded plastic house, and was on March 29 in normal type shaded plastic house. Both roots and shoot growth of ginseng were excellent in the bed soils with PPV-2, compared with other compounds used. We concluded that the PPV-2 could be promising a good bed soil substrate for organic ginseng cultivation in shaded plastic house.

• Journal of Power Electronics
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• 제17권2호
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• pp.514-521
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• 2017

This paper proposes a shadowing compensation method for the solar modules of grid-connected photovoltaic generation systems. The shadowing compensator (SC) implemented by the proposed shadowing compensation method is used only for the solar modules that can be shaded by predictable sources of shading. The proposed SC can simplify both the power circuit and the control circuit as well as improve power efficiency and utilizes a voltage equalizer configured by a modified multi-winding fly-back converter. The proposed SC harvests energy from the entire solar cell array to compensate for the shaded sub-modules of the solar cell array, producing near-identical voltages of all shaded and un-shaded sub-modules in the solar cell array. This setup prevents the formation of multiple peaks in the P-V curve under shaded conditions. Hardware prototypes are developed for the SCs implemented by the conventional and modified multi-winding fly-back converters, and their performance is verified through testing. The experimental results show that both SCs can overcome the multiple peaks in the P-V curve. The proposed SC is superior to the SC implemented by the conventional multi-winding fly-back converter.

• The Korean Journal of Ecology
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• 제16권3호
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• pp.329-339
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• 1993

Effects of relative light intensity and N, P fertilization on the growth and ramet dynamics of the rhizomatous plants, Arundinella hirta, Miscanthus sinensi and Spdiopogon sibiricus were studied in Chuncheon, Kangweon-Do. Ramets emerged in one pulse a year, withered in one pulse at the end of the growing season in M. sinensis and S. sibircus stands, while the birth and death pulse in A. hirta stands were two times. Total births of ramet were 9 times and 3.6 times greater in the unshaded fertilized stands of A. hirta and M. sinensis than in the shaded, However, those of S.sibiricus were 2.1 times greater in the shaded stands. Flowering rates of A. hirta, M.sinensis and S.sibiricus I the unshaded fertilized stands were 1.8, 2.7 and 1.04 times greater than in the shaded unfertilized stands, respectively. Height of ramets of A. hirta and M.sinensis were the hightest in the unshaded fertilized stands. However, that of s.sibiricus was the highest in the shaded fertilized stand. Aboveground production of A.hirta in the fertilized stand was 2.4 times greater in the unshaded stand than in the shaded one. Results of inflorescence frequency, shoot height and the ratio of aboveground to belowground were smiliar to the total births. The added fertilizer markedly increased the ramet density and the shoot productivity of three rhizomatous plants, especially of A. hirta.

• 한국태양에너지학회 논문집
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• 제32권spc3호
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• pp.220-227
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• 2012

The maximum power point tracking(MPPT) is important part pf PV generating system, because of nonlinear characteristic of PV array. Many MPPT algorithms have been developed and proposed, but partially shaded in PV generating system, these algorithms can not track maximum power point. This paper explains the partially shaded conditions in the PV generating system and describes a novel new MPPT algorithm. To verify the proposed novel algorithm, PSIM simulation tool is used in this paper, and proper 3kW PV module modeling is made. As a result, the right maximum power point(11PP) of PV PCS can be tracked directly under shading effect for any mismatched condition in solar array.

• Journal of Power Electronics
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• 제16권1호
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• pp.287-296
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• 2016

Conventional maximum power point tracking (MPPT) methods are ineffective under partially shaded conditions because multiple local maximum can be exhibited on power-voltage characteristic curve. This study proposes an improved cuckoo search (ICS) MPPT method after investigating the cuckoo search (CS) algorithm applied in solving multiple MPPT. The algorithm eliminates the random step in the original CS algorithm, and the conception of low-power, high-power, normal and marked zones are introduced. The adaptive step adjustment is also realized according to the different stages of the nest position. This algorithm adopts the large step in low-power and marked zones to reduce search time, and a small step in high-power zone is used to improve search accuracy. Finally, simulation and experiment results indicate that the promoted ICS algorithm can immediately and accurately track the global maximum under partially shaded conditions, and the array output efficiency can be improved.