• 전기의세계
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• 제28권11호
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• pp.45-51
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• 1979

Finte element methods are developed for the initial distribution problems which contain the surge potential circuits of high voltage transformer windings. The initial distribution of surge voltages in transformer windings are useful to the work to a practical engineering basis. However, the conventional methods of analyzing them so far are much complicated for practical designs. In this paper, the ability to solve surge potential field problems underlies the development of descreting methods to a lodal capacitive distribution-coefficients for determing the surge voltage relationship among a set of transformer coils. A practical example-the modeling of an antioscillation shield coil winding and hisercap winding is used to illustrate and evaluate these methods.

• 한국태양에너지학회 논문집
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• 제33권2호
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• pp.18-27
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• 2013

This paper presents a method for assessing the wind energy potential at complex terrain using probability distribution. And the proper probability models of the parameters estimating the wind energy are presented. Finally a mixture-Weibull determined by numerical methods procedure are proposed to assess the probability distribution of the energy potential at a site. The developed method is applied to the Kwanjungchun Bridge and compared with wind records which the neighboring weather station.

• The Korean Journal of Ecology
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• 제9권4호
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• pp.201-208
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• 1986

The water status of the leaves of several evergreen plants was investigated in order to discuss the geopgraphical distribution of them. Relastionship between relative water content and water potential of the leaves showed linear decrease for evergreen conifers but exponential decrease for Korean box tree (Buxus microphylla var. koreana). On the basis of the leaf water potential, the water status of the conifers during wintering was distinctly divided into three periods; hardening, cold resistance and dehardening, but lacking in those periods for the Korean box tree, where the status continously decreased. In the cold resistance the leaf water potentials were -23 bar for both spruce (Picea jezoensis) and yew (Taxus cuspidata). From these results and threshold temperature at beginning of hardening, distribution of the conifers was explained that in order of the red pine, the Korean white pine, the yew and the spruce the distribution could be extended at higher altitudes and in more northward areas, whereas the distribution of the Korean box tree was restricted to the lowland of temperate zone.

• 지구물리와물리탐사
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• 제19권4호
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• pp.200-211
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• 2016

횡단 전위 배열(cross potential array)과 동일열 전위배열(direct potential array) 자료를 뒷받침하여 다양한 수변 구조물의 누수 경로 예측을 가능하게 하는 배열을 제시하고 이를 D-Lux array 라고 명명하였다. 또한 D-Lux array 자료를 색으로 가시화한 하나의 행렬로 정리하여 D-Lux view라고 제시하고 D-Lux view에서 관찰되는 저 전위차 이상대의 위치로 누수 구역의 위치를 해석하였다. D-Lux view의 보다 직관적인 해석을 위해서 D-Lux array 자료와 동일열 전위 배열 자료를 함께 사용하여 각 지점들 사이의 전위차 자료를 각 지점의 전위값으로 역산하고 이를 이용하여 등전위 분포도를 작성하였다. 등전위 분포도는 그래프나 D-Lux view에서 알 수 없었던 누수의 유입구, 유출구 뿐만 아니라 경로까지 예측 가능하게 하였다. 수조 실험과 수치 해석으로 예비 탐사를 실시한 후 현장 탐사로 콘크리트 보와 필 댐에 대한 적용이 이루어졌다. 그 결과, 콘크리트 보와 필 댐에 대해 누수 경로 탐지가 가능함을 확인하였다.

• 식물분류학회지
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• 제50권2호
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• pp.154-165
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• 2020

염습지 개발과 기후온난화로 인해 해안지역의 생물 서식환경이 변화하고 있다. 환경변화로 인한 한반도 해안식물들의 미래분포변화를 추정하기 위해 MaxEnt 프로그램을 이용하여 해안식물 10종의 예상분포지를 분석하였다. 연구지역은 한반도 동·서·남해안 지역을 대상으로 하였다. 예상분포지 추정은 해안식물의 동아시아 지역 분포자료와 WorldClim 2.0의 19개 기후변수를 사용하였다. 3개의 대기대순환모델(general circulation model; CCSM4, MIROC-ESM 그리고 MPI-ESM-LR)과 4가지 온실가스시나리오(representative concentration pathways; 2.5, 4.5, 6.0 그리고 8.5), 그리고 2개 기간(2050와 2070)이 반영된 미래 기후변수로 미래 예상분포지를 예측하였다. 분석결과 연평균 기온이 적정 분포지 추정에 가장 높은 기여를 하였다. 미래에 분포가 감소할 것으로 예상되는 분류군은 갯메꽃, 갯방풍, 갯씀바귀, 갯완두, 해란초, 참골무꽃, 순비기나무였으며, 분포가 증가할 것으로 예상되는 분류군은 갯사상자로 나타났다. 미래 분포가 현재와 비슷할 것으로 생각되는 분류군은 수송나물, 통보리사초였다. 각 식물의 미래 예상분포지를 종합하여 분포평균을 계산한 결과 서해와 남해가 동해보다 기후변화의 영향을 크게 받을 것으로 예상된다. 이 결과는 해안식물의 보전전략을 수립하는데 기초자료로 활용될 것이다.

• 생태와환경
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• 제51권3호
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• pp.221-233
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• 2018

본 연구는 농업생태계 기후변화 지표식물의 현재와 미래의 분포 특성을 예측하고 분포에 영향을 미치는 요인을 파악하고자 수행되었다. 전국을 대상으로 총 108개 지점에서 지표식물 7종(광대나물, 꽃마리, 냉이, 서양민들레, 큰개불알풀, 큰망초, 서양금혼초)의 실제 분포 유무 자료를 수집하고 Maxent 모형을 적용하여 현재와 기후시나리오에 따른 미래의 잠재적 분포를 예측하였다. 기후변화에 따른 미래 분포 예측에서 냉이, 서양민들레, 큰개불알풀 3종은 전체 분포 면적은 감소하였지만 분포 범위는 그대로 유지되는 것으로 예측되었고, 큰망초와 서양금혼초 2종은 분포면적과 범위가 모두 확대되는 것으로 예측되었다. 광대나 물과 꽃마리 2종은 분포 면적이 급격히 줄어들어 국지적으로 분포하거나 일부 해안가에만 나타나는 것으로 예측되었다. 광대나물, 꽃마리, 냉이, 서양민들레, 큰개불알풀의 경우 토지피복도나 고도와 같은 비기후인자가 상대적으로 중요한 것으로 나타났고 큰망초와 서양금혼초는 기후인자가 중요한 것으로 확인되었다. 이와 같은 기후변화 지표식물의 분포 예측 특성은 향후 지표식물의 모니터링 방향과 관리 계획 설정에 활용될 것으로 기대된다.

• 환경생물
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• 제36권4호
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• pp.687-693
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• 2018

The active development of the global marine trade industries has been known to increase the inflows of marine invasive species and harmful organisms into the ecosystem, and the marine ecological disturbances. One of these invasive species, Ciona robusta, has now spread to the Korea Strait, the East Sea, and Jeju Island in connection with the climate change but not the Yellow Sea in Korea. Currently, the spread and distribution of C. robusta is increasingly damaging aquaculture and related facilities. Therefore, this study aims to identify the spread of C. robusta and potential habitats and to secure a data for the prevention of effective management measures due to climate change as well as damage the reduction in future through the prediction of spread. We used environmental variables in BioOracle. Also, the potential habitat and distribution of C. robusta was predicted using MaxEnt, a species distribution model. Two different RCP scenarios(4.5 and 8.5) were specified to predict the future distributions of C. robusta. The results showed that the biggest environmental factor affecting the distribution of C. robusta was the salinity as well as the highest distribution and potential habitats existent in the East Sea and around Jeju Island.

• Journal of Ecology and Environment
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• 제45권3호
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• pp.130-142
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• 2021

Background: Climate change is occurring rapidly around the world, and is predicted to have a large impact on biodiversity. Various studies have shown that climate change can alter the geographical distribution of wild bees. As climate change affects the species distribution and causes range shift, the degree of range shift and the quality of the habitats are becoming more important for securing the species diversity. In addition, those pollinator insects are contributing not only to shaping the natural ecosystem but also to increased crop production. The distributional and habitat quality changes of wild bees are of utmost importance in the climate change era. This study aims to investigate the impact of climate change on distributional and habitat quality changes of five wild bees in northwestern regions of Iran under two representative concentration pathway scenarios (RCP 4.5 and RCP 8.5). We used species distribution models to predict the potential range shift of these species in the year 2070. Result: The effects of climate change on different species are different, and the increase in temperature mainly expands the distribution ranges of wild bees, except for one species that is estimated to have a reduced potential range. Therefore, the increase in temperature would force wild bees to shift to higher latitudes. There was also significant uncertainty in the use of different models and the number of environmental layers employed in the modeling of habitat suitability. Conclusion: The increase in temperature caused the expansion of species distribution and wider areas would be available to the studied species in the future. However, not all of this possible range may include high-quality habitats, and wild bees may limit their niche to suitable habitats. On the other hand, the movement of species to higher latitudes will cause a mismatch between farms and suitable areas for wild bees, and as a result, farmers will face a shortage of pollination from wild bees. We suggest that farmers in these areas be aware of the effects of climate change on agricultural production and consider the use of managed bees in the future.

• KEPCO Journal on Electric Power and Energy
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• 제2권2호
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• pp.245-251
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• 2016

Despite the exponential throughput improvement in mobile communications systems, their ability to satisfy requirements of state-of-the-art and future applications of advanced metering infrastructure (AMI) is still under investigation. Challenges are mainly due to the inadequacy of third generation partnership project (3GPP) networks to support large amounts of devices simultaneously, while the number of AMI end-devices and the frequency of their data transmission increase with new AMI-based applications. In this introductory survey, innovative and future AMI applications and their communication requirements are first reviewed. Then, we identify challenges of 3GPP long term evolution (LTE) in enabling future AMI applications. More importantly, the latest improvements to LTE-A standard release 12 and 13 are reviewed and analyzed with regards to their potential to improve the quality of LTE-enabled AMI. It is found that 3GPP enhancements on machine type communications (MTC) standards will significantly enhance AMI communications. Beyond MTC specifications, non-MTC-specific enhancements such as carrier aggregation and multi-connectivity for user equipment will also contribute greatly to improving reliability and availability of AMI devices. The paper's focus is towards improved backhaul support for innovative and future AMI applications, beyond traditional automatic meter reading.

• International Journal of Computer Science & Network Security
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• 제21권6호
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• pp.54-60
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• 2021

Monte-Carlo GO is a computer GO program that is sufficiently competent without using knowledge expressions of IGO. Although it is computationally intensive, the computational complexity can be reduced by properly pruning the IGO game tree. Here, I achieve this by using a potential model based on the knowledge expressions of IGO. The potential model treats GO stones as potentials. A specific potential distribution on the GO board results from a unique arrangement of stones on the board. Pruning using the potential model categorizes legal moves into effective and ineffective moves in accordance with the potential threshold. Here, certain pruning strategies based on potentials and potential gradients are experimentally evaluated. For different-sized boards, including an official-sized board, the effects of pruning strategies are evaluated in terms of their robustness. I successfully demonstrate pruning using a potential model to reduce the computational complexity of GO as well as the robustness of this effect across different-sized boards.