• Journal of Korea Water Resources Association
• /
• v.30 no.1
• /
• pp.83-93
• /
• 1997

The purpose of the study is to analyze the sensitivity of the parameters that affect the runoff and water quality in the studied drainage basins. SWMM model is applied to the four drainage basins located at Namgazwa and Sanbon in Seoul and Gray Haven and Kings Creek in the USA. first of all, the optimum values of the parameters which have least simulation error to the observed data, are detected by iteration procedure. These are used as the standard values which are compared against the procedure. These are used as the standard values which are compared against the varied parameter values. In order to catch the effectiveness of the parameters to the computing result, the parameters are changed step by setp, and the results are compared to the standard results in flowerate and quality of the sewer. The study indicates that the discharge is greatly affected by the types of runoff surface, i.e., impervious area remarkably affects the peak flow and runoff volume while the surface storage affects the runoff volume at mild sloped basins. In addition, the major parameters affecting the pollution concentrations and loadings are the contaminant accumulation coefficient per unit area per time and the continuous dry weather days. Furthermore, the factors that affect the water quality during the initial rainfall period are the rainfall intensity, transport capacity coefficient and its power coefficient. Consequently, in order to simulate the runoff-water quality, it is needed to evaluate previous data in the research performed for the studied basins. To accurately estimated from the tributary areas and the rational computation methods of the pollutants calculation should be introduced.

• KIEAE Journal
• /
• v.16 no.5
• /
• pp.57-64
• /
• 2016

Purpose: Recently, lighting energy consumption in buildings has been gradually increasing and more studies are being carried out in order to solve this problem. Especially, the efficiency of the light-shelf system, which is a natural lighting system, has been recognized as a potential solution in addressing this problem and so various studies regarding the light-shelf system are being conducted. However, if high luminance material is used for the light-shelf system, glaring may occur in certain circumstances even though such material increases efficiency, and there are also difficulties related to maintenance and management in the case of an external light-shelf system. Therefore, the purpose of this study is to suggest modifications in relation to the reflectivity of the light-shelf system and introduce a rolling type light-shelf system with built-in cleaning equipment. In addition, a performance evaluation technique was established to verify its effectiveness. Method: In this study, we reviewed previous studies related to the light-shelf system and its performance. Then a testbed was established to assess the performance of the rolling-type light-shelf system suggested in this study. Also, the performance of the rolling-type light-shelf system suggested in this study was compared and analyzed with that of existent light-shelf systems in order to better verify the performance, and the uniformity ratio of illumination and lighting energy consumption were calculated for this purpose. Result: The results of the performance evaluation are as follows. 1) The performance evaluation result of the light-shelf system on the day of the summer solstice shows that $30^{\circ}$ is appropriate for the angle of light-shelf system, and the depth of the incoming natural light also increases as the angle of the light shelf increases. 2) It is possible to improve the uniformity ratio of illumination by increasing the reflectivity of the light shelf, and the reason for this is the increase in the amount of incoming light entering indoors due to the increased reflectivity of the light shelf. 3) The rolling type light-shelf system suggested in this study enables energy saving in comparison with existent light-shelf systems, and when the external illuminance decreases to 60,000 lx and 40,000 lx during the summer solstice due to factors such as the weather, the suggested light-shelf system can save energy by 12.1% and 5.1% respectively. Thus the light-shelf system proposed in this study is deemed to be effective in reducing energy costs.

• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.1
• /
• pp.101-119
• /
• 2018

In this study, we analyzed long-term measurements and air quality simulation results of four criteria air pollutants ($PM_{10}$, $O_3$, $NO_2$, and $SO_2$) for 10 years, from 2006 to 2015, with emphasis on trends of annual variabilities. With the observation data, we conducted spatial interpolation using the Kriging method to estimate spatial distribution of pollutant concentrations. We also performed air quality simulations using the CMAQ model to consider the nonlinearity of the secondary air pollutants such as $O_3$ and the influence of long-range transport. In addition, these simulations are used to deduce the effect of long-term meteorological variations on trends of air quality changes because we fixed the emissions inventory while changing meteorological inputs. The nation-wide inter-annual variability of modeled $PM_{10}$ concentrations was $-0.11{\mu}g/m^3/yr$, while that of observed concentrations was $-0.84{\mu}g/m^3/yr$. For the Seoul Metropolitan Area, the inter-annual variability of observed $PM_{10}$ concentrations was $-1.64{\mu}g/m^3/yr$ that is two times rapid improvement compared to other regions. On the other hand, the inter-annual variability of observed $O_3$ concentrations is 0.62 ppb/yr which is larger than the simulated result of 0.13 ppb/yr. Magnitudes of differences between the modeled and observed inter-annual variabilities indicated that decreasing trend of $PM_{10}$ and increasing trend of $O_3$ are more influenced by emissions and oxidation states than meteorological conditions. We also found similar patterns in $NO_2$. However, $NO_2$ trends showed greater regional and seasonal differences than other pollutants. The analytic approach used in this study can be applicable to estimate changes in factors determining air quality such as emissions, weather, and surrounding conditions over a long term. Then analysis results can be used as important data for air quality management planning and evaluation of the chronic impact of air quality.

• Journal of Plant Biotechnology
• /
• v.43 no.1
• /
• pp.21-29
• /
• 2016

Remote Sensing (RS) is a technique to obtain necessary information in a non-contact and non-destructive method by using various sensors on the surface, water or atmospheric phenomena. These techniques combine elements such as sensors, and platform and information communication technology (ICT) for mounting the sensor. ICT has contributed significantly to the success of smart agriculture through quantification and measurement of environmental factors and information such as weather, crop and soil management to distribution and consumption stage, as well as the production stage by the cloud computer. Remote sensing techniques, including non-destructive non-contact bioimaging (remote imaging) is required to measure the plant function. In addition, bioimaging study in plant science is performed at the gene, cellular and individual plant level. Recently, bioimaging technology is considered the latest phenomics that identifies the relationship between the genotype and environment for distinguishing phenotypes. In this review, trends in remote sensing in plants, plants diagnostics and response to environment and status of plants phonemics research were presented.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.20 no.2
• /
• pp.214-227
• /
• 2018

An object oriented crop model was developed to perform crop growth simulation taking into account complex interaction between biotic and abiotic factors in an agricultural ecosystem. A set of classes including Atmosphere class, Plant class, Soil class, and Grower class were designed to represent weather, crop, soil, and crop management, respectively. Objects, which are instance of class, were linked to construct an integrated system for crop growth simulation. In a case study, yield of corn and soybean, which was obtained at an experiment farm in Rural Development Administration from 1984 to 1986, were compared with yield simulated using the integrated system. The integrated system had relatively low error rate of corn yield, e.g., <4%, under sole and intercropping conditions. In contrast, the system had a relatively large underestimation error for above ground biomass except for grain compared with those observed for corn and soybean. For example, estimates of biomass of corn leaf and stem was 31% lower than those of observed values. Although the integrated system consisted of simple models, the system was capable of simulating crop yield under an intercropping condition. This result suggested that an existing process-based model would be used to have more realistic simulation of crop growth once it is reengineered to be compatible to the integration system, which merits further studies for crop model improvement and implementation in object oriented paradigm.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.4 no.1
• /
• pp.1-11
• /
• 2002

This study was conducted to reveal the effects of local climatic conditions on the early growth of Korean white pine progeny test stands. For this, stand variables such as mean DBH, mean height, basal area per hectare, and volume per hectare by stand age and locality were first measured and summarized for each stand. Based on these statistics, annual increments for 10 years from stand age 10 to 20 were calculated for each of stand variables. The effects of local climatic conditions as one of environmental factors on the growth were then analyzed by both a topoclimatological method and a spatial statistical technique. From yearly climatic estimates,30 climatic indices which affect the tree growth were computed for each of the progeny test stand. The annual increments were then correlated with and regressed on the climatic indices to examine effects of local climatic conditions on the growth. Gapyung area provided the best conditions for the early growth of Korean white pine and Kwangju area ranked second. On the other hand, the growth pattern in Youngdong ranked last overall as expected. It is also found that the local growth patterns of Korean white pine in juvenile stage were affected by typical weather conditions. The conditions such as low temperature and high relative humidity provide favor environment for the early growth of Korean white pine. Especially, it was concluded that the low temperature is a main factor influencing the early growth of Korean white pine based on the results of correlation analysis and regression equations developed far the prediction of annual increments of stand variables.

• Journal of Environmental Impact Assessment
• /
• v.23 no.5
• /
• pp.406-416
• /
• 2014

When abnormal taste and odor were detected in the tap water of the North-Han river watershed during the dry season in late 2011, excessive nutrients with algal growth in the Lake Uiam and weather factors were considered to be among its causes. The nutrients, in particular, originated from domestic sewage in the Chuncheon area. This study was conducted to investigate relations between the algal growth in the Lake Uiam and the contribution of nutrients from public sewage treatment works (PSTWs) in Chuncheon city, and based on this to analyze the environmental impact. Nutrients in the Lake Uiam have already been accumulated to the level of eutrophication. Even in winter, the conditions in the lake such as retention time and water temperature were favorable to boost algal growth. After phosphorus treatment processes were introduced, the PSTWs in the Lake Uiam watershed were able to reduce the total phosphorus loads by 43%. The algal concentrations in the Lake Uiam also dropped by about 7%. The nitrogen treatment efficiencies in the PSTWs, on the other hand, remained almost the same after the introduction of the phosphorus treatment processes. To solve these problems more efficiently, it is necessary to develop management strategies for the upstream area of the Lake Uiam and set plans to improve nitrogen treatment operation and management for the PSTWs in Chuncheon.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.21 no.4
• /
• pp.229-237
• /
• 2019

This study was conducted to estimate annual reference evapotranspiration (ET₀) for the agro-climatic zones for rice paddy fields in South Korea between 1980 and 2015. The daily ET₀ was estimated by applying the Penman-Monteith method to meteorological data from 61 weather stations provided by Korean Meteorological Administration (KMA). The average of annual ET₀ from 1980 to 2015 was 1334.1±33.89 mm. The ET₀ was the highest at the Southern Coastal Zone due to their higher air temperature and lower relative humidity. The ET₀ had significantly increased with 2.81 mm/yr for the whole zones over 36 years. However, the change rate of it was different among agro-climatic zones. The annual ET₀ highly increased in central zones and eastern coastal zones. In terms of correlation coefficient, the temporal change of the annual ET₀ was closely related to variations of four meteorological factors (i.e., mean, minimum temperatures, sunshine duration, and relative humidity). The results demonstrated that whole Korean agro-climatic zones have been undergoing a significant change in the annual ET₀ for the last 36 years. Understanding the spatial pattern and the long-term variation of the annual ET₀ associated with global warming would be useful to improve crop and water resource managements at each agro-climatic zone of South Korea.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.1
• /
• pp.49-58
• /
• 2017

The phenomena that we experience in everyday life such as snow, rain, wind, and temperature are referred to as weather, and the average state of atmospheric phenomena that occur over a long period of time in a specific region is referred to as climate. In addition, significant variation of climate compared to the average state is referred to as climate change. Concrete structures can have various problems when exposed to elements. Among the problems, the freeze-thaw problem due to extreme climatic factors such as heavy rain and snowfall has become a particularly significant issue recently. The concrete that has been subjected to repeated freeze-thaw rather than too high or low temperature shows serious degradation of durability, and the performance of structures with degraded performance is difficult to recover. Therefore, in this study, concrete durability performance with respect to freeze-thaw from curing conditions change due to wind speed and sunshine exposure time. Concrete freeze-thaw experiment are performed. using wind speed and sunlight exposure time. Also, performance based evaluation through the satisfaction curve based on the freeze-thaw test results are performed.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.4
• /
• pp.357-365
• /
• 2020

While numbers of apartment housing are continually rising in the domestic housing construction industry, apartment contractors are currently developing plane models, upgrading facilities, and relevant technology, and investing much efforts to meet the higher demands of consumers. However, the construction process of apartment housing involves the intricate properties of the construction industry such as materials, workforce, equipment, weather, and unpredictable situations. If any of these factors becomes discordant and results in interference and interruption of the construction process, then defects, both functional and aesthetic, are likely to occur due to errors in the plan of industry organizers and constructors. Therefore, this research identifies the types of defects in an apartment construction project and analyzes their relative importance. Firstly, this research reviews the previous research trends and will reduce the needs of this research. Afterward, defect repair costs corresponding to the different defect types are calculated by applying results of the research and performing frequency analysis on defect types included in 'Tenant preliminary research' on apartments constructed by Company A. As a result of analyzing the importance of defect type, the top six activities, including tile, floor, paper hanging, PL window, cabinetry, and kitchen cabinet, are found to be of high importance, and the top six activities in question need of repair and management of defects first. The results of this study will help establish a plan to initially respond to such problems as refusal to move in and filing a defect suit against delay in repairing defects.