• 한국농공학회논문집
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• 제57권1호
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• pp.47-57
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• 2015

Along with climate change, the occurrence and severity of natural disasters have been increased globally. In particular, the increase of localized heavy rainfalls have caused severe flood damage. Thus, it is needed to consider climate change into the estimation of design flood, a principal design factor. The main objective of this study was to estimate design floods for an agricultural reservoir watershed based on the RCP (Representative Concentration Pathways) scenarios. Gyeryong Reservoir located in the Geum River watershed was selected as the study area. Precipitation data of the past 30 years (1981~2010; 1995s) were collected from the Daejeon meteorological station. Future precipitation data based on RCP2.6, 4.5, 6.0, 8.5 scenarios were also obtained and corrected their bias using the quantile mapping method. Probability rainfalls of 200-year frequency and PMPs were calculated for three different future spans, i.e. 2011~2040; 2025s, 2041~2070; 2055s, 2071~2100; 2085s. Design floods for different probability rainfalls were calculated using HEC-HMS. As the result, future probability rainfalls increased by 9.5 %, 7.8 % and 22.0 %, also design floods increased by 20.7 %, 5.0 % and 26.9 %, respectively, as compared to the past 1995s and tend to increase over those of 1995s. RCP4.5 scenario, especially, resulted in the greatest increase in design floods, 37.3 %, 36.5 % and 47.1 %, respectively, as compared to the past 1995s. The study findings are expected to be used as a basis to reduce damage caused by climate change and to establish adaptation policies in the future.

• 한국환경과학회지
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• 제16권3호
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• pp.347-355
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• 2007

In this paper, estimation of the compressive strength of the concrete incorporating blast furnace slag subjected to high temperature was discussed. Ordinary Portland cement and blast furnace slag cement (BSC;30% of blast furnace slag) were used, respectively. Water to binder ratio ranging from 30% to 60% and curing temperature ranging from $20^{\circ}C{\sim}65^{\circ}C$ were also chosen for the experimental parameters, respectively. At the high temperature, BSC had higher strength development at early age than OPC concrete and it kept its high strength development at later age due to accelerated latent hydration reaction subjected to high temperature. For the strength estimation, the Logistic model based on maturity equation and the Carino model based on equivalent age were applied to verify the availability of estimation model. It was found that fair agreements between calculated values and measured values were obtained evaluating compressive strength with logistic curve. The application of logistic model at high temperature had remarkable deviations in the same maturity. Whereas, the application of Carino model showed good agreements between calculated values and measured ones regardless of type of cement and W/B. However, some correction factors should be considered to enhance the accuracy of strength estimation of concrete.

• 한국조경학회지
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• 제49권4호
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• pp.64-73
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• 2021

본 연구의 목적은 소셜미디어에서 공유되는 지오태그 이미지를 활용하여 이용자가 인지하는 북한산국립공원의 경관미를 평가하는 방법을 제시하는 것이다. 연구에서 제시된 평가 방법은 크게 지오태그 이미지 데이터의 수집, 경관 이미지 식별, 조망대상 확률 지수를 적용한 누적가시도 분석의 과정으로 진행되었다. 본 연구에서 데이터로 사용한 램블러(Ramblr)는 국내에서 많은 이용자를 보유하고 있는 아웃도어 활동 지원 어플리케이션으로, 이로부터 북한산국립공원에 대한 총 110,954장의 지오태그 이미지를 수집하여 경관미 평가에 활용하였다. 수집된 지오태그 이미지들은 Google Vision API를 활용해 이미지의 내용을 해석하였으며, 이후 군집분석을 통해서 전체 수집한 사진을 총 11개의 경관이미지 유형과 9개의 비경관이미지 유형으로 구분하였다. 추출한 경관이미지를 바탕으로 북한산국립공원의 경관 유형을 분석한 결과, 봉우리나 산맥과 같은 지형적 특성과 관련한 이미지 유형이 가장 많은 비중을 차지하였으며, 그 외 임내 경관, 단풍경관, 수경관이 주요한 경관 유형으로 발견되었다. 도출된 경관미 평가맵에서는 이러한 주요 경관 유형의 비중과 특성에 따라 표고 및 경사가 높을수록 전반적으로 높은 경관미를 보였다. 그러나 일부 저지대 및 완경사를 지닌 진입지역에서도 높은 경관미가 확인되었다. 또한 북한산 지역이 도봉산 지역보다 경관미가 높게 평가되었으며, 도봉산 지역의 경우에는 표고 및 경사가 높음에도 불구하고, 상대적으로 낮은 경관미가 확인되었다. 이는 경관미가 물리적인 환경 조건뿐만 아니라, 경관을 조망하는 탐방객들의 휴양 활동과도 크게 관계하고 있음을 보여준다. 이처럼 지오태그 이미지의 누적 가시도를 활용한 경관미 평가는 사람들의 인식에 기반한 경관적 가치를 지리적으로 이해하고, 그 편차를 식별할 수 있도록 함으로써 향후 북한산국립공원의 경관 계획 및 관리에 유용하게 활용될 수 있을 것으로 기대된다.

• 한국환경복원기술학회지
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• 제22권6호
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• pp.1-14
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• 2019

Carbon storage is one of the regulating ecosystem services provided by urban street trees. It is important that evaluating the economic value of ecosystem services accurately. The carbon storage of street trees was calculated by measuring the morphological parameter on the field. As the method is labor-intensive and time-consuming for the macro-scale research, remote sensing has been more widely used. The airborne Light Detection And Ranging (LiDAR) is used in obtaining the point clouds data of a densely planted area and extracting individual trees for the carbon storage estimation. However, the LiDAR has limitations such as high cost and complicated operations. In addition, trees change over time they need to be frequently. Therefore, Structure from Motion (SfM) photogrammetry with unmanned Aerial Vehicle (UAV) is a more suitable method for obtaining point clouds data. In this paper, a UAV loaded with a digital camera was employed to take oblique aerial images for generating point cloud of street trees. We extracted the diameter of breast height (DBH) from generated point cloud data to calculate the carbon storage. We compared DBH calculated from UAV data and measured data from the field in the selected area. The calculated DBH was used to estimate the carbon storage of street trees in the study area using a regression model. The results demonstrate the feasibility and effectiveness of applying UAV imagery and SfM technique to the carbon storage estimation of street trees. The technique can contribute to efficiently building inventories of the carbon storage of street trees in urban areas.

• 원예과학기술지
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• 제33권6호
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• pp.845-853
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• 2015

The objective of this study was to predict the timing of nitrogen (N) demand through analyzing chlorophyll fluorescence (ChlF), soil-plant analysis development (SPAD), and normalized difference vegetation index (NDVI), which are positively correlated with foliar N concentration in star cluster (Pentas lanceolata). The plants were grown in potting soil under optimal conditions for 30 d, followed by weekly irrigation with five concentrations (0, 4, 8, 16, and 24 mM) of N for an additional 30 d. These five N application levels corresponded to leaf N concentrations of 2.62, 3.48, 4.00, 4.23, and 4.69%, respectively. We measured 13 morphological and physiological parameters, as well as the responses of these parameters to various N-fertilizer treatments. The general increases in Dickson's quality index (DQI), above-ground dry weight (DW), total DW, flowering rate, ${\Delta}F/Fm$', and qP in response to treatment with 0 to 8 mM N were similar to those of SPAD, NDVI, and Fv/Fm. Consistent and strong correlations ($R^2$= 0.60 to 0.85) were observed between leaf N concentration (%) and SPAD, NDVI, ${\Delta}F/Fm$', and above-ground DW. Validation of leaf S PAD, NDVI, and ${\Delta}F/Fm$' revealed that these vegetation indices are accurate predictors of leaf N concentration that can be used for non-destructive estimation of the proper timing for N-solution irrigation of P. lanceolata. Moreover, irrigation with 8 mM N-fertilizer i s recommended w hen leaf N concentration, SPAD, NVDI, and ${\Delta}F/Fm$' ratios are reduced from their saturation values of 4.00, 50.68, 0.64, and 0.137%, respectively.

• 한국산림과학회지
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• 제99권6호
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• pp.891-899
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• 2010

이 연구의 목적은 선택실험기법을 활용한 조건부 로짓 모델을 이용하여 산림경관기능이 가지는 경제적 가치를 추정하는데 있다. 이를 위해 산림경관의 속성과 수준을 선정하였는데, 속성은 산림형태, 임상, 소밀도, 휴양적 요소, 지불의사금액 등이 그것이다. 이를 토대로 SAS 9.1을 이용하여 Orthogonal과 Balanced를 이루는 96개 선택 집합을 4개 타입으로 구성하였으며, 서울을 포함한 7개 광역시 시민을 모집단으로 설정하여 연간 가구당 지불할 의사를 면접조사방법으로 총 280부를 조사하였다. 그 결과, Non-ASC 모형에서 Mcfadden' ${\rho}$는 0.21, 우도통계량은 -2,631로 나타났다. 그리고 산림경관에 대한 가구당 평균 지불의사금액은 266,723원으로 나타났다.

• 한국농공학회논문집
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• 제49권6호
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• pp.11-20
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• 2007

In order to make the way to determine the instream flow more practically, we have investigated many case studies and reviewed reports and papers. To validate instream flow level suggested by the case studies, DAWAST and HEC-RAS model were applied to the Gap-stream watershed in Daejeon city. Flow-duration analysis was performed both with the stream flow data gauged in the Indong, Boksu, and Hoeduck stations, and with the stream flow data estimated by the DAWAST model and the specific discharge method. Instream flow was determined among the flow-duration analysis, DAWAST, HEC-RAS model and mass balance approach. It was satisfied with various factors such as target water quality, water depth for eco-system and resorts, water surface width, flow velocity for landscape in dry season. The study suggested that the mean low flow could be replaced into the instream flow for the preliminary study because the instream flow considering ecosystem, landscape, water-friendly environment and water quality was generally close to the mean low flow.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• 제2호
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• pp.120-129
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• 2004

Urban stream restoration projects can improve water quality, wildlife habitats, urban landscape, outdoor recreation spaces, and urban microclimate. The objectives of this research were to investigate temperature cooling effect of urban streams by using satellite imagery, to evaluate environmental variables related to stream cooling effect, and to estimate the cooling effect of the Cheonggye stream restoration project of Seoul, Korea. Findings of this research can be summarized as follows. First, a method of estimating temperature distribution around urban streams by using satellite imagery was developed. Scatter plots of distance from stream edges and average temperature obtained through multiple buffering were used for the estimation. Second, urban temperature cooling effect of streams was estimated by comparing background temperature and temperature of each buffer zone. Third, environmental factors affecting stream cooling effect were also identified. Fourth, the temperature cooling effect of the restoration project was estimated based on three scenarios. An estimated cooling effect based on the average cooling effect of existing tributaries showed the most significant effect; $2.0^{\circ}C$ lower than the present level at the edge of the renovated stream. It was estimated that the temperature of the same area would be $1.4^{\circ}C$ cooler than the present level if the cooling effect of the Yangjaechun was used as the bench mark But the effect would be $1.2^{\circ}C$ lower than the present level if environmental variables related to the temperature cooling effect of urban streams were used as the bench mark.

• 한국조경학회지
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• 제23권2호
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• pp.1-16
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• 1995

This study was carried out to suggest method which can be used to improve competitive power of theme parks. The characteristics of Hybrid Conjoint Analysis were described and its usefulness for identification of specific types of service theme parks have to provide was tested "Lotte World, " "Seoul land," and "farmland" were selected as study areas, and .7 attributes with 3 levels were utilized for analyses. Master design with 81 profiles was constructed to meet the requirement of ′Compromise Plan 1,′and data was collected by in-personal interviews on the study areas. Respondents were grouped by cluster analysis, and their characteristics were analyzed by discriminant analysis. Then, part-worth of each attribute . was estimated by stagewise estimation model Calibrated model of each group did not show part-worths of attributes clearly because both main effects and 2-way interaction effects were included in the models. Therefore, calibrated models′ coefficients were used to calculate utilities of all possible combinations of attributes levels. The results showed that managers of theme parks have several options for providing a new service: the combination of attribute levels with the highest utility is they however, they can choose the other combinations with next highest utlities is they can not afford it. Several suggestions were described to cope with the problems when Hybrid Conjoint Analysis is applied to landscape architectural study.

• 한국조경학회지
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• 제26권1호
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• pp.51-58
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• 1998

The opening of an event in a given geographical area may be defined as an innovation. Visitors to the event adopt the innovation; therefore, their visitation patterns since the opening can be regarded as a diffusion process. Bass' model of diffusion process was applied to analyzing weekly visitation of Kwang-ju Viennale. Parameters of the Bass' model were estimated by regression analysis, and then reviewed in terms of applicability. Actual estimation of event visitation was implemented by calculation of the three parameters of the model based on the actual data. After comparing estimated value with actual value, it was concluded that Bass' model is applicable to estimating event visitation as far as it is the only prediction method available at this point.