• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.120-132
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• 2008

Remotely sensed images from a satellite can be applied for detecting and quantifying spatial and temporal variations in terms of landuse & landcover, crop growth, and disaster for agricultural applications. The purposes of this study were to analyze topography using DEM(digital elevation model) and classify landuse & landcover into 10 classes-paddy field, dry field, forest, bare land, grass & bush, water body, reclaimed land, salt farm, residence & building, and others-using Landsat TM images in North Korea. Elevation was greater than 1,000 meters in the eastern part of North Korea around Ranggang-do where Kaemagowon was located. Pyeongnam and Hwangnam in the western part of North Korea were low in elevation. Topography of North Korea showed typical 'east-high and west-low' landform characteristics. Landcover classification of North Korea using spectral reflectance of multi-temporal Landsat TM images was performed and the statistics of each landcover by administrative district, slope, and agroclimatic zone were calculated in terms of area. Forest areas accounted for 69.6 percent of the whole area while the areas of dry fields and paddy fields were 15.7 percent and 4.2 percent, respectively. Bare land and water body occupied 6.6 percent and 1.6 percent, respectively. Residence & building reached less than 1 percent of the country. Paddy field areas concentrated in the A slope ranged from 0 to 2 percent(greater than 80 percent). The dry field areas were shown in the A slope the most, followed by D, E, C, B, and F slopes. According to the statistics by agroclimatic zone, paddy and dry fields were mainly distributed in the North plain region(N-6) and North western coastal region(N-7). Forest areas were evenly distributed all over the agroclimatic regions. Periodic landcover analysis of North Korea based on remote sensing technique using satellite imagery can produce spatial and temporal statistics information for future landuse management and planning of North Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1421-1433
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• 2014

In this study, appropriate probability distribution and parameter estimation method were selected to perform snowfall frequency analysis. Generalized Extreme Value (GEV) and Probability Weighted Moment Method (PWMM) appeared to be the best fit for snowfall frequency analysis in Korea. Snowfall frequency analysis applying GEV and PWMM were performed for 69 stations in Korea. Peak snowfall corresponding to recurrence intervals were estimated based on frequency analysis while snow loads were calculated using the estimated peak snowfall and specific weight of snow. Design snow load map was developed using 100-year recurrence interval snow load of 69 stations through Kriging of ArcGIS. The 2009 Korean Building Code and Commentary for design snow load was assessed by comparing the design snow loads which calculated in this study. As reflected in the results, most regions are required to increase the design snow loads. Thus, design snow loads and the map were developed from based on the results. The developed design snow load map is expected to be useful in the design of building structures against heavy snow loading throughout Korea most especially in ungaged areas.

• Journal of Korea Water Resources Association
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• v.32 no.4
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• pp.457-467
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• 1999

No complete methods for estimating soil loss, included by rain storms, from a small watershed are available yet, and the best recommended method is to use measured data from the watershed. When no measured data is available from the watershed, empirical models for estimating the soil loss, such as the Universal Soil Loss Equation(USLE), is well recommended in practice. For using this equation, it is necessary to estimated the rainfall erosivity, commonly expressed as R, of the watershed. In this study, first we collected data of the probable rainfalls with the return periods of 2, 5, 10, 20, 30, 50, 80, 100, 200, and 500-yr and with the duration hours of 0.5, 1, 2, 3, 6, 12, and 24-hr. Using this data, we calculated the design values for R for the return period of 24-hr at each major rainfall-measuring station nationwide. Then we constructed the iso-erodent map of Korea for each return period of the 24-hr design storm. This study shows that the 24-hr duration iso-erodent map of the 5-yr return period is very similar to the annual average iso-erodent map of Korea. This study also shows that the 24-hr duration R-values of a certain return period can be estimated by multiplying certain parameters, obtained from this study, to the 24-hr duration R-values for the 5-yr return period or the annual average R-values. Finally, the R-values of the design storm with the 24-hr return period obtained from this study can be used for designing the settling basins at small watersheds.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1194-1202
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• 2012

Remotely sensed satellite images can be applied to monitor and obtain land surface information on inaccessible areas. We classified paddy field area in North Korea based on on-screen digitization with visual interpretation using 291 RapidEye satellite images covering the whole country. Criteria for paddy field classification based on RapidEye imagery acquired at different time of rice growth period was defined. Darker colored fields with regular shape in the images with false color composite from early May to late June were detected as rice fields. From early July to late September, it was hard to discriminate rice canopy from other type of vegetation including upland crops, grass, and forest in the image. Regular form of readjusted rice field in the plains and uniform texture when compared with surrounding vegetation. Paddy fields classified from RapidEye imagery were mapped and the areas were calculated by administrative district, province or city. Sixty six percent of paddy fields ($3,521km^2$) were distributed in the west coastal regions including Pyeongannam-do, Pyeonganbuk-do, and Hwanghaenam-do. The paddy field areas classified from RapidEye images showed less than 1% of difference from the paddy field areas of North Korea reported by FAO/WFP (Food and Agriculture Organization/World Food Programme).

• Journal of KIISE:Software and Applications
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• v.37 no.12
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• pp.882-891
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• 2010

Many automated dynamic test data generation technique have been proposed. The techniques evaluate fitness of test data through executing instrumented Software Under Test (SUT) and then generate new test data based on evaluated fitness values and optimization algorithms. Previous researches and experiments have been showed that these techniques generate effective test data. However, optimization algorithms in these techniques incur much time to generate test data, which results in huge test case generation cost. In this paper, we propose a technique for reducing the time of evaluating a fitness of test data among steps of dynamic test data generation methods. We introduce the concept of Fitness Evaluation Program (FEP), derived from a path constraint of SUT. We suggest a test data generation method based on FEP and implement a test generation tool, named ConGA. We also apply ConGA to generate test cases for C programs, and evaluate efficiency of the FEP-based test case generation technique. The experiments show that the proposed technique reduces 20% of test data generation time on average.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.217-224
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• 2010

This study was carried out to quantify potential effects of the surrounding ocean on the observed air temperature at coastal weather stations in the Korean Peninsula. Daily maximum and minimum temperature data for 2001-2009 were collected from 66 Korea Meteorological Administration (KMA) stations and the monthly averages were calculated for further analyses. Monthly data from 27 inland sites were used to generate a gridded temperature surface for the whole Peninsula based on an inverse distance weighting and the local temperature at the remaining 39 sites were estimated by recent techniques in geospatial climatology which are widely used in correction of small - scale climate controls like cold air drainage, urban heat island, topography as well as elevation. Deviations from the observed temperature were regarded as the 'apparent' sea effect and showed a quasi-logarithmic relationship with the distance of each site from the nearest coastline. Potential effects of the sea on daily temperature might exceed $6.0^{\circ}C$ cooling in summer and $6.5^{\circ}C$ warming in winter according to this relationship. We classified 25 sites within the 10 km distance from the nearest coastline into 'coastal sites' and the remaining 15 'fringe sites'. When the average deviations of the fringe sites ($0.5^{\circ}C$ for daily maximum and $1.0^{\circ}C$ for daily minimum temperature) were used as the 'noise' and subtracted from the 'apparent' sea effects of the coastal sites, maximum cooling effects of the sea were identified as $1.5^{\circ}C$ on the west coast and $3.0^{\circ}C$ on the east and the south coast in summer months. The warming effects of the sea in winter ranged from $1.0^{\circ}C$ on the west and $3.5^{\circ}C$ on the south and east coasts.

• Journal of Korea Water Resources Association
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• v.30 no.4
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• pp.317-326
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• 1997

The Palmer Drought Severity Index has been ectensively used to quantitatively evaluate the drought severity at a location for both agricultural and water resources management purposes. In the present study the Palmer-type formula for drought index is drived for the whole country by analyzing the monthly rainfall and meteorological data at nine stations with a long period of records. The formula is then used to compute the monthly drought severity index at sixty-eight rainfall stations located throughout the country. For the past five significant drought periods the spatial variation of each drought is shown as a nationwide drought index map of a specified duration from which the relative severity of drought throughout the country is identifiable for a specific drought period. A comparative study is made to evaluate the relative severity of the significant droughts occurred in Korea since 1960's. It turned out that '94-'95 drought was one of the worst both in the areal extent and drought severity. It is found that the Palmer-type formula is a very useful tool in quantitatively evaluating the severity of drought over an area as well as at a point. When rainfall and meteorological forecast become feasible on a long-term basis the method could also be utilized as a tool for drought forecasting.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.12-23
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• 2019

This study aims to suggest analysis schemes of urban forests acting as wind ventilation corridor(wind ventilation forest). For this purpose, wind corridor forests were classified into three types: wind-generating forests(WGF), wind-spreading forests (WSF), and wind-connecting forests(WCF), and they were classified into three grades. WGF, WSF and WCF were classified based on the density of forest type map, vegetation index, and ventilation networks, respectively. As a result of analyzing wind corridor forests for Daegu Metropolitan City(883.56㎢), the area of WGF was classified as 443.1㎢ and distributed in the northern and southern regions of Daegu Metropolitan City. Among them, the first grade of WGF occupied the largest area(345.59㎢) and the highest rate(54.44%) in Dalseong-gun. On the other hand, WGF was not found in Jung-gu, because this administrative district is isolated from the forest area. WSF was 32.4㎢, which included representative urban parks of Daegu Metropolitan City, and WSF were found relatively much in Suseong-gu and Dalseong-gun. However, WSF were distributed throughout Metropolitan City, and the vegetation index was not high. The ventilation network that can form WCF included major rivers and roads in Daegu Metropolitan City, but this network was not connected to the urban park from the outer forest. Therefore, it was judged that the formation of WCF connecting WGF outside the city and WSF inside the city would be important. The results of this study can be used as a basic data for systematic wind corridor forest projects, and can be used as basic data for establishing guidelines for wind corridor forest analysis at national and local levels.