• KIEAE Journal
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• 제8권4호
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• pp.19-27
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• 2008

The carbon dioxide is brought from the energy consumption and regarded as a criteria material to estimate the Global Warming Potential. Building shares about 30% in national energy consumption and affects to environment as much as the energy consumption. But there is not enough data to forecast the amount of the carbon dioxide during the maintenance stage. Various factors are related with the energy consumption and carbon dioxide emission such as the physical area, the building exterior area, the maintenance type and location. Among these factors, the building carbon-dioxide emission can be estimated by the overall building characteristics such as the maintenance area, the number of household, the heating type, etc., The physical amount such as the thickness of the insulation and window infiltration could explained the limited scope and might not be use to estimate the total carbon-dioxide emission energy because the each value could not include or represent the overall building. In this paper, it provided the estimation model of the carbon-dioxide emission, explained by the overall building characteristics. These factors are shown as the maintenance area, no. of household, the heating type, the volume of the building, the ratio of the window to wall area etc., For providing the estimation model of th carbon-dioxide emission, it conducted the corelation analysis to filter the variables and suggested the estimation model with the power model and multiple regression model. Most of the model have a good statistics and fitted in the curve line.

• 한국지리정보학회지
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• 제20권1호
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• pp.42-55
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• 2017

식생의 기후 적응력은 지역에 따른 상황 및 공간적 패턴이 다르게 나타나기 때문에 픽셀 스케일의 접근이 필요하다. 본 연구에서는 위성영상 기반 식생지수에 대해 PLS 회귀분석을 적용하여 식생의 생산성에 영향을 미치는 기후요인을 평가하고 남한지역의 미래 산림 생산성을 예측하였다. 그 결과, 최고강수분기의 평균기온(Bio8), 최저강수분기의 평균기온(Bio9), 최저강수월의 강수량(Bio14) 변수가 식생의 생산성에 높은 영향을 미치는 것으로 분석되었다. 미래 기후시나리오 자료를 이용하여 예측된 2050년의 식생 생산성은 전체적으로 감소하는 것으로 나타났으며, 특히 고지대에서 크게 감소하는 것으로 분석되었다. 이러한 결과는 기후에 민감한 지역의 식생에 대한 생산성 모니터링과 미래 기후변화로 인한 산림 탄소 저장량의 변화를 평가하는데 있어 유용하게 활용될 수 있을 것으로 판단된다.

• KIEAE Journal
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• 제15권4호
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• pp.45-52
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• 2015

Purpose: Foam concrete is the concrete that contains large amount of air voids inside. In general, the density of foam concrete depends on parameters like water/binder ratio, foam volume, aggregate and pozzolan content, etc. Method: In this study, the effect of foam volume and fly ash content on dry density is investigated intensively in order to find the relationship between each parameter and their abilities to counteract with each other. According to the above information, though there are quite a number of studies on the effect micro fiber on foam concrete at low volume fractions, there is still lack of information especially on the high fiber content side. The objective of the second study is to investigate further on the use of micro fiber at higher volume fraction and fill in the lacking information. Beside from this study, the investigation of the effect of micro-fiber (polypropylene) to enhance the properties of foam concrete is also carried out. Result: Of the two variables that are investigated in this study, the foam volume and the fly ash content, show significant effect on the properties of foam concrete. The foam volume tends to decrease the density and strength of foam concrete. In the second part of our study, a large fibre volume fraction is proved to be able to evidently increase the flexural strength of foam concrete up to about 40% due to the effect of fibre bridging over the crack and a significant number of fibres that intercepts the crack surfaces. However, the compressive strength is found to decrease severely due to the occurrence of large pores as the result of fibre being added into concrete mixture.

• KIEAE Journal
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• 제16권3호
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• pp.89-94
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• 2016

Purpose: This study aimed at developing an artificial neural network (ANN) model to predict the optimal start moment of the setback temperature during the normal occupied period of a building. Method: For achieving this objective, three major steps were conducted: the development of an initial ANN model, optimization of the initial model, and performance tests of the optimized model. The development and performance testing of the ANN model were conducted through numerical simulation methods using transient systems simulation (TRNSYS) and matrix laboratory (MATLAB) software. Result: The results analysis in the development and test processes revealed that the indoor temperature, outdoor temperature, and temperature difference from the setback temperature presented strong relationship with the optimal start moment of the setback temperature; thus, these variables were used as input neurons in the ANN model. The optimal values for the number of hidden layers, number of hidden neurons, learning rate, and moment were found to be 4, 9, 0.6, and 0.9, respectively, and these values were applied to the optimized ANN model. The optimized model proved its prediction accuracy with the very storing statistical correlation between the predicted values from the ANN model and the simulated values in the TRNSYS model. Thus, the optimized model showed its potential to be applied in the control algorithm.

• Journal of Ecology and Environment
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• 제38권3호
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• pp.327-334
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• 2015

We investigated the current and potential spatial distributions and habitable areas of Biston robustum and Camellia japonica in South Korea in order to provide useful data for the conservation of C. japonica and minimize the damage caused by B. robustum. It was predicted that, by 2070, although B. robustum would be widely distributed throughout the Korean Peninsula, except for the western and eastern coastal areas, it would be narrowly distributed along the Sokcho-si and Goseong-gun coastlines in Gangwon Province. C. japonica is currently located along the southern coastline but its critical habitable area is predicted to gradually disappear by 2070. Assessment of the potential distribution probabilities of B. robustum and C. japonica revealed that the area under the curve (AUC) values were 0.995 and 0.991, respectively, which indicate high precision and applicability of the model. Major factors influencing the potential distribution of B. robustum included precipitation of wettest quarter and annual precipitation (BIO16 and BIO12), whereas annual mean temperature and mean temperature of wettest quarter (BIO1 and BIO8) were important variables for explaining C. japonica distribution. Overlapping areas of B. robustum and C. japonica were $11,782km^2$, $5447km^2$, and $870km^2$ for the current, 2050-predicted, and 2070-predicted conditions, respectively, clearly showing a dramatic decrease in area. Although it is predicted that B. robustum would cause continuous damage to C. japonica in the southern part of the Korean Peninsula, such impacts might diminish over time and become negligible in the future.

• Journal of Ecology and Environment
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• 제33권2호
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• pp.165-173
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• 2010

Soil respiration ($R_S$) is a critical component of the annual carbon balance of forests, but few studies thus far have attempted to evaluate empirical regression models in $R_S$. The principal objectives of this study were to evaluate the relationship between $R_S$ rates and soil temperature (ST) and soil water content (SWC) in soil from a cool-temperate deciduous broad-leaved forest, and to evaluate empirical regression models for the prediction of $R_S$ using ST and SWC. We have been measuring $R_S$, using an open-flow gas-exchange system with an infrared gas analyzer during the snowfree season from 1999 to 2001 at the Takayama Forest, Japan. To evaluate the empirical regression models used for the prediction of $R_S$, we compared a simple exponential regression (flux = $ae^{bt}$Eq. [1]) and two polynomial multiple-regression models (flux = $ae^{bt}{\times}({\theta}{\nu}-c){\times}(d-{\theta}{\nu})^f:$ Eq. [2] and flux = $ae^{bt}{\times}(1-(1-({\theta}{\nu}/c))^2)$: Eq. [3]) that included two variables (ST: t and SWC: ${\theta}{\nu}$) and that utilized hourly data for $R_S$. In general, daily mean $R_S$ rates were positively well-correlated with ST, but no significant correlations were observed with any significant frequency between the ST and $R_S$ rates on periods of a day based on the hourly $R_S$ data. Eq. (2) has many more site-specific parameters than Eq. (3) and resulted in some significant underestimation. The empirical regression, Eq. (3) was best explained by temporal variations, as it provided a more unbiased fit to the data compared to Eq. (2). The Eq. (3) (ST $\times$ SWC function) also increased the predictive ability as compared to Eq. (1) (only ST exponential function), increasing the $R^2$ from 0.71 to 0.78.

• 한국환경복원기술학회지
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• 제15권6호
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• pp.29-41
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• 2012

This study was conducted in Ningxia Hui autonomous region, located at southern part of Mu Us sand land in China. To investigate relationships between windbreak effect and installation cost of sand barriers, plastic net is utilized by using four kind of heights (0.2, 0.3, 0.4 and 0.5m) and four kind of porosities (20, 30, 50 and 70%). These heights and porosities are measured for estimating distances for effective windbreak. It is shown that porosity and the distance have a positive relationship at same heights and porosity on ground indicates a constant figure when height reaches a certain level, regardless of the porosity. This implies that there is a difference of level of windbreak with different porosities; however, distance of windbreak effect is same at the same height of sand barrier. As a result of comparison between porosity of sand barrier on the ground and installation cost in each sand barrier with various heights and porosities (16 combinations), 0.4m and 0.5m height sand barriers describe highest economical efficiency. Within two variables, we concluded that height has a higher impact on windbreak effect than porosity.

• The Korean Journal of Ecology
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• 제25권2호
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• pp.83-91
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• 2002

내연산의 삼림식생을 대상으로 ZM 식물사회학적 방법에 의해 군락단위 및 그 하위 단위를 분류하고, 분류된 각 단위와 환경사이의 상관관계를 서열법으로 해석하여 내연산 산림식생관리를 위한 기초자료를 제공할 목적으로 본 연구를 수행하였다. 군락단위는 신갈나무군락, 굴참나무군락, 소나무군락, 서어나무군락, 느티나무군락이 구분되었고, 하위단위는 철쭉꽃군과 참회나무군, 굴참나무군락에서 우산나물군, 털조록싸리군 및 찰피나무군, 느티나무군락에서 까치박달군과 고욤나무군이 각각 세분되었다. 따라서 내연산 일대의 산림은 5개군락, 7개군으로 총 9개의 식생단위로 분류되었다. CCA 방법으로 식생과 환경사이의 상관관계 분석 결과 내연산 지역의 식생단위는 해발과 가장 높은 상관관계가 있는 것으로 나타났다. 신갈나무군락의 철쭉꽃군과 참회나무군은 해발고와 지형이 높은 곳과 노암율이 낮은 곳에 각각 분포하는 경향이 있다. 한편 느티나무군락은 신갈나무군락과 역의 관계로 나타났다. 앞으로 산림식생관리시 특히 계곡림에 대해서는 교목층의 우점종들이 상관적으로 이질적인 모습을 하고 있더라고 하나의 관리단위로 고려되어야 할 것으로 판단되었다.

• Journal of Ecology and Environment
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• 제38권2호
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• pp.133-143
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• 2015

Freshwater macrophytes improve the structural heterogeneity of microhabitats in water, often providing an important habitat for zooplankton. Some studies have focused on the overall influence of macrophytes on zooplankton, but the effects of macrophyte in relation to different habitat characteristics of zooplankton (e.g., epiphytic and pelagic) have not been intensively studied. We hypothesized that different habitat structures (i.e., macrophyte habitat) would strongly affect zooplankton distribution. We investigated zooplankton density and diversity, macrophyte characteristics (dry weight and species number), and environmental parameters in 40 shallow wetlands in South Korea. Patterns in the data were analyzed using a self-organizing map (SOM), which extracts information through competitive and adaptive properties. A total of 20 variables (11 environmental parameters and 9 zooplankton groups) were patterned onto the SOM. Based on a U-matrix, 3 clusters were identified from the model. Zooplankton assemblages were positively related to macrophyte characteristics (i.e., dry weight and species number). In particular, epiphytic species (i.e., epiphytic rotifers and cladocerans) exhibited a clear relationship with macrophyte characteristics, while large biomass and greater numbers of macrophyte species supported high zooplankton assemblages. Consequently, habitat heterogeneity in the macrophyte bed was recognized as an important factor to determine zooplankton distribution, particularly in epiphytic species. The results indicate that macrophytes are critical for heterogeneity in lentic freshwater ecosystems, and the inclusion of diverse plant species in wetland construction or restoration schemes is expected to generate ecologically healthy food webs.

• Journal of Ecology and Environment
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• 제38권1호
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• pp.15-23
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• 2015

This study was conducted in an effort to provide important clues pertaining to the conservation and restoration of Aporia crataegi by identifying the spatial distribution characteristics of the current habitats, prospective habitats, and future habitats of A. crataegi in accordance with climate changes. To determine the distribution of A. crataegi, data from a total of 36 collecting points throughout South Korea, North Korea, China, Japan, Mongolia, and Russia are used. The spatial distributions of the data were examined through MaxEnt modeling. The distribution probability rates exceeded 75% at 18 locations among the 36 species occurrence locations, with Gangwon province showing the highest distribution probability in South Korea. The precision of the MaxEnt model was remarkably high, with an AUC value of 0.982. The variables that affect the potential distribution of A. crataegi by more than 10% are the degree of temperature seasonality, the amount of precipitation in the warmest quarter, the annual mean temperature, and the amount of precipitation in the driest month, in that order of importance. It was found that the future potential distribution area of A. crataegi continuously moves northward over time up to 2070s. In addition, the area of the potential distribution showing a habitable probability rate that exceeds 75% in northeast Asia was $28,492km^2$, where the area of potential distribution in the north part of Korean peninsula was $20.404km^2$ in size. Thus, it is anticipated that the most important future habitats of A. crataegi in the northeast Asia will be North and South Hamgyeong provinces and Ryanggang province near Mt. Baekdoosan in the northern area of the Korean peninsula.