• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.44 no.5
• /
• pp.629-636
• /
• 2024

The purpose of this study is to monitor changes in the water surface of reservoirs in verifiable areas in Korea using satellite images and to analyze the water surface area and water storage. The target area of this study is the Daecheong dam of the Geumgang(Riv.), which supplies water to some areas in the Chungcheong area. A study was conducted to detect water surface area by using the Sentinel-1(SAR-C) image and the optical image of Sentinel-2(MSI) among the various observation sensors of satellite images. The correlation between the reservoir's water storage volume, which is ground measurement data, and the extracted water surface area was analyzed. As a result of the analysis, the coefficient of determination(R²) between water surface area and daily storage using SAR images was analyzed to be 0.9242, and in the analysis using Sentinel-2's MSI optical image, it was analyzed to be correlated at 0.8995. In addition, it is analyzed that the water storage volume of the water surface area extracted from the image using the relationship between the water storage volume and the water surface area represents a hydrograph similar to the actual water storage volume. This study is a basic study for the use of satellite images in unmeasured/non-access areas such as North Korea, and plans to conduct a study to analyze annual changes and long-term trends in major dam reservoirs in North Korea by reflecting the results obtained through this study.

• Korean Journal of Environmental Agriculture
• /
• v.16 no.4
• /
• pp.356-364
• /
• 1997

To investigate the water quality status of agricultural water source for greenhouse area in Gyeongnam, the surface water quality was examined six times from October in 1995 to March in 1996 at five areas in Gyeongnam. The pH values of surface water were in the range of 6.6${\sim}$9.1 pH in Kimhae and Changnyong areas were out of range in 6.0${\sim}$8.5 which was water quality standard for agriculture. The DO values of surface water were relatively high with average 10.0mg/l in Kimhae, Changnyong, Sacheon and Chinju areas except for Haman area. The BOD values of surface water exceeded water quality standard for agriculture(8.0mg/l) in three sites and one site in Haman and Sacheon, respectively. The COD values of surface water exceeded water quality standard for agriculture(8.0mg/l) in Kimhae, Changnyong and Haman. The ${NH_4}^+-N$ values in surface water of Changnyong and Haman areas were 1.21mg/l and 2.75mg/l, respectively. The average values of $NO_3\;^--N$ in surface water was appropriate for agriculture. The values of $K^+,\;Na^+,\;Mg^{2+},\;Ca^{2+},\;{PO_4}^{3-}$ and $SO_4^{2-}$ in Haman were the highest of those of the others. And Pb was below 0.1mg/l which was water quality standard for agriculture. The average values of Cu, Cd and Zn were below water quality standard for agriculture. Between COD and SS in surface water was positively correlated with r$=0.799^{{\ast}{\ast}}$. BOD in surface water was positively correlated with $NH_4\;^+-N,\;PO_4\;^{3-},\;SS,\;K^+,\;Na^+$ and $Cl^-$. Surface water pollution status of agricultural water source of greenhouse areas in Gyeongnam was in order of Chinju< Sacheon< Kimhae< Changnyong< Haman area.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.6
• /
• pp.566-574
• /
• 1984

The oceanic effect on the coastal climate, the air temperature and the humidity, in Korea was studied by using the meteorological and the sea surface temperature data compiled from 1962 to 1981. The fluctuation of sea surface temperature plays an important role in determining the air temperature and the humidity in the coastal area, The sea surface temperature is higher than the air temperature from September to March in the western coastal area, and from September to April in the southern and the eastern coastal areas, It is found that in March the air temperature begins to surpass the sea ourface temperature in the western coastal area, and in April in the southern and the eastern coastal areas. On the basis of the multiple regression analysis it is found that the oceanic effect on the coastal climate, the air temperature and the humidity, in the western coastal area is different that in the southern and the eastern coastal areas.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.2
• /
• pp.56-67
• /
• 1999

This study was performed to suggest the basic data and plans for the establishment of safe water supply plans in simple water supply piped system in the rural areas. In 4 different places, 24 points of water sources 36 points of taps from water sources were sampled. Of the whole 60 points, 55 points were ground water and 5 points were surface water. 14 items were measured for the analysis of water quality on each samples. The measured items were analyzed again by statistical method ; cluster analysis and principle components analysis. The results of this study are as followed. 1) In water quality analysis on water sources, 4 items, bacteria, E.coli, NH3-N and Fe exceed the standard. Of 24 points, 20 points(83%) on bacteria, 1 point(4%) on NH3-N and Fe exceed the standard. 2) In water quality analysis on near and remote taps, 4 items, bacteria, E.coli, NH3-N and Fe , exceed the standard. Of 36 points, 20 points (81%) on bactria, 1 pint(3%) on NH3-N and Fe exceed the standard. 3)Cluster analysis on water quality shows the differences by the kinds of water sources, geographical characteristics and distance from water sources. 4) Principle components analysis on ground water shows that Factor 1 and Factor 3 are natural fluctuation by the content of soil. Also, Factor 2 and Factor 4 are penetration of pollutants to underground. Therefore, it is needed to take deeper ground water in order to prevent from pollution in the areas which have ground water as water source . 5) Principle components analysis on surface water shows that Factor 1 is penetration of vacteria from surface to water source when rainfalls. Also, Factor 2 is fluctuation of water quality by the geographical characteristics. Therefore, the counterplans against non-point pollution source must be taken. Filtration and disinfection facilities are needed in the areas which have surface water as water source.

• Journal of the Ergonomics Society of Korea
• /
• v.7 no.1
• /
• pp.21-30
• /
• 1988

The investigation of the surface areas, volumes and sizes (circumference, length, breadth) changes has been performed on women during menstruation, non-menstruation, pregnancy and post-pregnancy periods. (1) During menstruation and non-menstruation periods: The subjects were 30 healthy women from 19 to 24 years of age. The changes of lower leg areas were measured using the paper replacement method, showing an increase of 0.71% in surface during the menstruation period. The changes of lower 1g volumes were measured by the water replacement method, showing an increase of 1,74% in volume during the menstruation period. The correlation between the surface area changes and the volume changes was of r=0.45. The greatest change among the four parts of the leg was found at the ankle in both experiments. We measured also the foot length(1), the ball of foot girth(2), the foot breadth(3), the instep height (4), the instep girth(5), the ankle girth(6), the calf circumference(7) and we found the greatest changes in(4)=3,92% in(5)=0.79% and in (7) =0.84%. (2) During pregnancy and post-pregnancy periods: The subjects were 3 women, two pregnants(both from the 24th to the 36th week of pregnancy during the experiment) and one post-pregnant(from the second week to the eighth week during the expriment). For the first two subjects, we measured only the last 6 items of the preceding experiments(foot length(1),ball of foot girth(2), (3), (5), (6), (7)), Showing the greatest changes in the instep girth(5) and the calf circumference(7). In the case of the post-pregnant subject, these two items (5) and(7) decreased sharply during the second, third and fourth week and remain approximately the same afterwards.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.39 no.2
• /
• pp.113-122
• /
• 2021

Urban expansion, particularly converting sub-urban areas to residential and commercial land use in metropolitan areas, has been considered as a significant signal of regional economic development. However, this results in urban climate change. One of the key impacts of rapid urbanization on the environment is the effect of UHI (Urban Heat Island). Understanding the effects of urban land cover change on UHI is crucial for improving the ecology and sustainability of cities. This research reports an application of remote sensing data, GIS (Geographic Information Systems) for assessing effects of urban land cover change on the LST (Land Surface Temperature) and heat budget components in Ho Chi Minh City, where is one of the fastest urbanizing region of Vietnam. The change of urban land cover component and LST in the city was derived by using multi-temporal Landsat data for the period of 1998 - 2020. The analysis showed that, from 1998 to 2020 the city had been drastically urbanized into multiple directions, with the urban areas increasing from approximately 125.281 km² in 1998 to 162.6 km² in 2007, and 267.2 km² in 2020, respectively. The results of retrieved LST revealed the radiant temperature for 1998 ranging from 20.2℃ to 31.2℃, while that for 2020 remarkably higher ranging from 22.1℃ to 42.3℃. The results also revealed that given the same percentage of urban land cover components, vegetation area is more effective to reduce the value of LST, meanwhile the impervious surface is the most effective factor to increase the value of the LST.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.755-759
• /
• 2000

The determination of surface topography is believed to be extremely important in the areas of contact mechanics, adhesion and friction. In order to describe topography of various frictional surface. the wear test was carried out under different experimental conditions in dry friction. And fractal descriptors was applied to frictional surface of laser modified steel with image processing System. These descriptors to analyze surface structure are fractal dimension. Surface fractal dimension can be determined by sum of intensity difference of surface pixel. Topography of frictional surface can be effectively obtained by fractal dimensions.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1999.11a
• /
• pp.240-246
• /
• 1999

The determination of surface topography is believed to be extremely important in the areas of contact mechanics, adhesion and friction. In order to describe topography of various frictional surface, the wear test was carried out under different experimental conditions in dry friction. And fractal descriptors was applied to frictional surface of laser modified steel with image processing system. These descriptors to analyze surface structure are fractal dimension. Surface fractal dimension can be determined by sum of intensity difference of surface pixel. Topography of frictional surface can be effectively obtained by fractal dimensions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.404-409
• /
• 2000

The determination of surface morphology is believed to be extremely important in the areas of contact mechanics, adhesion and friction. In order to describe morphology of various rubbed surface, the wear test was carried out under different experimental conditions in lubricating wear. And fractal descriptors was applied to rubbed surface of hydraulic driving material with image processing system. These descriptors to analyze surface structure are fractal dimension. Surface fractal dimension can be determined by sum of intensity difference of surface pixel. Morphology of rubbed surface can be effectively obtained by fractal dimensions.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.11a
• /
• pp.23-28
• /
• 2000

The determination of surface morphology is believed to be extremely important in the areas of contact mechanics, adhesion and friction. In order to describe morphology of various rubbed surface, the wear test was carried out under different experimental conditions in lubricating wear. And fractal descriptors was applied to rubbed surface of hydraulic driving material with image processing system. These descriptors to analyze surface structure are fractal dimension. Surface fractal dimension can be determined by sum of intensity difference of surface pixel. Morphology of rubbed surface can be effectively obtained by fractal dimensions.