• Journal of Communications and Networks
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• 제8권1호
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• pp.49-58
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• 2006

One of the first decisions that a radio network designer must take is the location of base stations and the distance between them in order to give the best coverage to a region and, possibly, to reduce deployment costs. In this paper, the authors give an insight to this matter by presenting a possible solution to a real problem: Planning the base stations layout for a universal mobile telecommunications system (UMTS) in the city of Barcelona. At the basis of this problem, there is the interdependence between coverage and capacity in a wideband-code division multiple access (W-CDMA) system, which is a new element in the planning of BS layout for mobile communications. This aspect has been first treated with an analytical study of the cell coverage range for a specific environment and service. The achieved results have been checked with the help of snapshot simulations together with a geographical information system (GIS) tool incorporated in the simulator that allows to perform analysis and to visualize results in a useful way. By using the simulator, it is also possible to study a more complex environment, that of a set of base stations providing multiple services to a large number of users.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.429-432
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• 2003

In this paper, a novel neural network approach is proposed for cleaning robot to complete coverage path planning with obstacle avoidance in stationary and dynamic environments. The dynamics of each neuron in the topologically organized neural network is characterized by a shunting equation derived from Hodgkin and Huxley's membrane equation. There are only local lateral connections among neurons. The robot path is autonomously generated from the dynamic activity landscape of the neural network and the previous robot location without any prior knowledge of the dynamic environment.

• 한국환경과학회지
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• 제28권11호
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• pp.1027-1032
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• 2019

This study aimed to analyze the prioritized area for the functional change of agricultural reservoir according to the rapid urbanization and social changes through the mapping method. Changwon-si, Gimhae-si, and Jinju-si in Gyeongnam province were selected as the study area, considering the results of land-use and cluster analysis. As the planning unit of management area, watershed was used and land coverage map from 1975 to 2015 were analyzed for changes of land use. The reduction ratio (%) of farmland was calculated for identifying the changes in 2013 compared to 1975. As a result, the reduction ratio was 11.9% for Changwon-si, 12.2% for Gimhae-si and 9.3% for Jinju-si, and the number of watershed having functionally reduced potential-area was relatively high in the proportion to the city size.

• 로봇학회논문지
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• 제16권2호
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• pp.122-129
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• 2021

For the Simultaneous Localization and Mapping (SLAM) problem, a different path results in different SLAM results. Usually, SLAM follows a trail of input data. Active SLAM, which determines where to sense for the next step, can suggest a better path for a better SLAM result during the data acquisition step. In this paper, we will use reinforcement learning to find where to perceive. By assigning entire target area coverage to a goal and uncertainty as a negative reward, the reinforcement learning network finds an optimal path to minimize trajectory uncertainty and maximize map coverage. However, most active SLAM researches are performed in indoor or aerial environments where robots can move in every direction. In the urban environment, vehicles only can move following road structure and traffic rules. Graph structure can efficiently express road environment, considering crossroads and streets as nodes and edges, respectively. In this paper, we propose a novel method to find optimal SLAM path using graph structure and reinforcement learning technique.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권9호
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• pp.538-545
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• 2000

In this paper we proposed a new map construction and path planning method for mobile robot. In our proposed method first we introduced triangular representation map that mobile robot can navigate through shorter path and flexible motion instead of grid representation map for mobile robot navigation. method in which robot can navigate complete space through as short path as possible in unknown environment is proposed. Finally we proposed new path planning method in a quadtree representation map. To evaluate the performance of our proposed new path planning method in a quadtree representation map. To evaluate the performance of our proposed triangular representation map it was compared with the existing distance transform path planning method. And we considered complete coverage navigation and new path planning method through several examples.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.176-179
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• 2009

In this study, Urban Climate Simulation was performed using 3-Dimensional Urban Canopy Model. The characteristics of urban thermal environment was analyzed by classifying land coverage and increasing natural land coverage ratio. The results are as follows. The characteristics of the land coverage on urban thermal environment formation can be summarized by the effects like higher temperature on the artificial coverage, and the contrary effects on the natural coverage. When the water coverage 100% was made up, maximum temperature was declined by $5.5^{\circ}C$, humidity by the 6.5g/kg, wind velocity by 0.6m/s, convective sensible heat by $400W/m^2$ and the evaporative latent heat was increased by $370W/m^2$ compared to when artificial coverage 100% was formed. These simulation results need to be constructed as DB which shows urban quantitative thermal characters by the urban physical structure. These can be quantitative base for suggesting combinations of the building and urban planning features at the point of the desirable urban thermal environment as well as analysing urban climate phenomenon.

• 농촌계획
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• 제25권3호
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• pp.115-128
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• 2019

The A1B scenario predicts that the mean air temperature of South Korea will rise up to $3.8^{\circ}C$ by 2071. However, the effects of ecosystem services are declining because of various environmental problems, including climate change, land use change, stream intensification, non-point pollution, and untreated garbage. Moreover, horticultural sites which have various ecosystem services suffer highly absorbed heat from the heat island phenomenon associated with climate change. Therefore, we analyzed the heat island phenomenon occurring in an protected horticulture estimated area in Saemanguem, South Korea. Using an advanced measurement method, we examined the air temperature change derived from water channels as well as open spaces. The CFD analysis of coverage ratio 85% design showed wind speed of 2.09 m/s and temperature of $38.07^{\circ}C$. At a coverage ratio of 70%, the wind speed was improved to 2.61 m/s and the temperature was improved to $36.89^{\circ}C$. In Alternative 2 with wetlands and trees, the wind speed was 2.71 m/s and the temperature was $35.90^{\circ}C$. When the coverage ratio decreases to 55%, the wind speed increases showing 3.06 m/s and the temperature decreases showing $35.18^{\circ}C$.

• 한국의학물리학회지:의학물리
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• 제12권2호
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• pp.171-175
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• 2001

본 연구에서는 고정틀 정위방사선치료장비에 사용되는 치료계획시스템과 무고정틀 정위방사선치료시스템에 사용되는 치료계획시스템을 이용하여 intracranial 표적을 대상으로 치료계획을 수립하였다. 치료계획을 평가하기 위하여 RTOG-9005 규정서에서 정위방사선치료계획의 정도관리를 위하여 사용한 Planning Target Volume Coverage를 확인하고 Conformity Index(CI)와 Homogeneity Index(HI)를 구하였다. 이들 값으로부터 두 치료계획시스템에서 계산한 치료계획이 동일함을 알 수 있었다.

• 한국환경복원기술학회지
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• 제23권4호
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• pp.85-96
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• 2020

The honeybee serves for most entomophilous flowers. They are a core species for maintaining the ecological system. Though the urban ecological system needs bees' mediation of pollination as well, we have little understanding on how the honeybee reacts to the physical environments of an urban city. This study is a basic research to enhance the potential environment for pollination in an urban area and aims to review the urban environmental variables which are highly linked to the pollination mediations by the honeybee. The study composed a Maxent model by adopting nine urban environmental variables and the locations of the Apis mellifera's appearances around 52 spots in Seoul. The variables reflect the ecology of the Apis mellifera. Of the urban environmental variables used for the model composition, six variables were found as not having meaningful correlations with the Apis mellifera's appearances and finally, building coverage, actual vegetation and land cover were selected as the appearance variables of the Apis mellifera. The AUC, the reliability indicator of the final model was 0.791 (sd=0.077). And the importance data of the variables used for the model were 55.6%, 27.9%, and 16.5% for building coverage, actual vegetation and land cover, respectively. The result of the study showed that the building coverage has the highest correlation with the appearance of the honeybee. And, as per the actual vegetation, the artificially tree planted area as well as the cultivated field and meadow in an urban area were functioning as the most important environmental conditions for the honeybee to be inhabitable. The study is expected to be utilized as the base material for the urban planning and park green area planning to enhance the potential environment for pollination in an urban area.

• 한국환경생태학회지
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• 제26권3호
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• pp.437-445
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• 2012

수위 및 침수기간이 저수하안 식생공법의 식생피도에 미치는 영향을 규명하기 위하여 심곡천 실험구에 적용된 식생공법에 대한 시공모니터링을 수행하였다. 시공모니터링의 항목은 각 공법의 출현식물종과 피복도, 토양의 이화학적 특성, 수위 및 수질 등이다. 모니터링 결과, 2010년도 5월 1차 조사에서는 모든 저수하안 식생공법의 식물생육은 양호하였으나, 2011년 약 1주일 이하의 침수가 있었던 6월 2차 조사에서는 적용된 식생공법의 식물 생육상태 및 피도가 부분적으로 불량하였다. 그리고 조사 기간 중 침수기간이 약 8주로 가장 길었던 8월 3차 조사에서는 갈대를 제외한 대부분의 식생이 고사하였다. 하지만 침수기간이 2주 이내로 3차 조사 때 보다 수위가 하강한 10월 4차 조사에서는 식물의 출현종수와 피복도가 점차 회복되는 것으로 관찰되었다. 이에 정량적 분석을 위하여 식생공의 식물출현종수 및 피도와 수위, 침수기간에 대한 상관성 분석을 실시하였다. 그 결과 출현종수 및 피도는 수위 및 침수기간과는 음(-)의 상관성을 나타내었는데, 침수기간이 수위보다 다소 더 높은 상관성이 있는 것으로 분석되었다.