• Journal of Digital Convergence
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• v.14 no.12
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• pp.225-230
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• 2016

Dam is built to supply water necessary for life stably and reduce the damage caused by heavy rains. Recently there has been required the analysis and utilization of spatial information on the area around the dam because construction of the dam gives a great impact on the environment of the surrounding area. In this study, we build spatial information about the submerged district due to dam construction using drone and propose the effective method for analysis of the spatial information. As a result, orthoimage and DSM of study area were constructed effectively. Change of submerged district of this area was calculated according to the analysis of spatial information. Building and analyzing spatial information carried out in this study are expected to be utilized as the basis in related fields.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.2
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• pp.56-62
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• 2017

In this research, reverse engineering was applied to the product manufactured by "Vanzetti" from Italy to develop a localized cryogenic submerged pump used in small-scale LNG liquefaction plants. The results of modal analysis of the impeller and shaft confirmed that the resonance frequency of the impeller and shaft played an important role in the rotor. Modal analysis of the rotor confirmed that the forcing frequency had no influence on the resonance phenomenon.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.842-853
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• 2008

In the construction of dam, the key factor which decides the type of dam is security of materials resource. Because of the large scale earth work, the ability to supply the materials is essential part about economical efficiency. The research is the case study about controlling the plan to secure the material resources in the design of Buhang multipurpose dam. In case of Buhang multipurpose dam, at that time of basic design, it was planned to use a rock fill material. From the detail investigation about the river bed accumulative layer widely spread on the submerged district on the basic design, the research is accomplished to replace rock material with gravel material. After the investigation of whole reserves of gravel material, estimation of conformity as dam construction material from analysis of grain size distribution, the case study of oversea construction, and the material property comparison between rock fill material and gravel fill material, it is verified th possibility of using the gravel fill. Thereafter, the analysis of dam stability using a gravel fill material is accomplished. Finally, A gravel fill material can be used as the main construction material of CFRD, therefore the efficiency of resource recycling in the submerged area is maximized, and the established plan is more advantageous to stability, constructibility, environmentibility than the case of using a rock fill.

• Membrane and Water Treatment
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• v.10 no.5
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• pp.331-338
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• 2019

This study aimed to investigate the membrane fouling and sludge characteristics in a pilot-scale submerged membrane bioreactor (MBR) operated under low temperature ($7^{\circ}C$). To elucidate the mechanisms of membrane fouling at low temperature, we studied the correlation between MBR performances and physicochemical properties of sludge including extracellular polymeric substance (EPS), relative hydrophobicity (RH) and floc size during long-term operation. The MBR was shown able to remove chemical oxygen demand (COD) stably and efficiently (>90 %) in the case of overgrowth of filamentous bacteria (bulking sludge) at low temperature. On the other hand, the occurrence of filamentous bulking greatly accelerated membrane fouling, as indicated by membrane filtration period of 14 days for filamentous bulking at $7^{\circ}C$, in comparison with that of 27 days for non-bulking sludge at $24^{\circ}C$ The overgrowth of filamentous bacteria resulting from low-temperature condition led to an increased release of EPS, higher RH, smaller floc size and lower fractal dimension of sludge. These factors accelerated the formation of compact cake layer on membrane surface in association with performance diminution in terms of increase in transmembrane pressure (TMP) of the membrane and thus the decrease in membrane permeability.

• Spatial Information Research
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• v.18 no.4
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• pp.43-53
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• 2010

A dam is effective in stable supply of water required in daily life and reduction of damage from floods. hut a lot of land or houses arc submerged due to the construction of a darn heavily affecting environment in surrounding areas. In order to improve and support daily life environment. surrounding a dam, many projects have been conducted. and the study has focused on analyzing bow to calculate error characteristics of scale effect for submerged area by using GIS spatial overlay. First, as a result of areal error in submerged area by scale based on a 1/3,000 digital topographic map, it was found that the 1/5,000 digital topographic map is 9.5 times, 9.0 times and 10.5 times more accurate than the 1/25,000 digital topographic map, respectively, in the total of areal error, standard error and areal error for submerged area. Second, as a result of analysis on areal error in areas surrounding a dam, it has been found that Jinan-eup in Jinan-gun registered the largest difference in area within 2km and 2~5km catchment area by recording 13.8 times and 20.6 times, respectively, in the 1/5,000 digital topographic map compared to the 1/25,000 digital topographic map. In addition, in areas out of catchment area within 2km, the area of occupation was very small, so there were no characteristics in error. The out of catchment area, Nami-myeon in Geumsan-gun recorded the largest errors of 31.8 times. Finally, it was found that the ratio of the total areal error in area surrounding a dam, standard error and the total areal error in the entire area using 1,5000 digital topographic map is 7.4 times, 11.8 times and 7.4 times more accurate than the 1/25,000 digital topographic map.

• Journal of Environmental Impact Assessment
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• v.13 no.6
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• pp.307-314
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• 2004

Among large developmental projects, those of the government and public institutions with the total budget of more than 50billion wons can be executed only when the feasibility of the project has been testified through the procedure of preliminary feasibility study. Multi-purpose dams are public structures that can supply water, produce electricity, and control flood, they belong to large national projects that require legal evaluation procedures such as preliminary feasibility study and environmental impact assessment(EIA). The index that should be considered to be important in dam plan is the migration of residents in submerged district. The importance in the preliminary feasibility study is 4.93 points(98.6 in the scale of 100 at maximum). Among the 12 assessment elements of the policy and economy in the preliminary feasibility study, the element of environment assessment is turned out to be 4.68 points in the assessment importance (93.5 in the scale of 100 at maximum), which is the second in the total ranking and the first in the field of policy, indicating that the element is very important in dam construction planning.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.2
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• pp.61-69
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• 2005

The coastal erosion and the look of a heap which are mainly occurred in the district along the coast are found for various forms such as the estuary closing, the estuary sand bar the development of the coast sand bar, and the modification of coastline. Recently, due to the coastal development, these transformations have been intensified. The change of coast, which has been made slow progress is required long-term study on a searching examination of the root cause and a suggestion of a counter measure. In this research, ortho aerial photos were produced to analyze volumes of topographical alternations that have been progressed fer the long run, by 10s cycle from 1940s through 1990s, to compute accurate volumes of coastline variation, through a datum point and G.C.P (Ground Control Point). Also in this study, without respect to water level, the coastline variation was analyzed by using comparatively analyzed a Idlest land map, a cadastral map. And to analyze topographical variation volumes, the tidal station's materials was used under consideration f3r tide. Finally, topographical variation volumes are comparatively analyzed through surveying and sounding and a point of fine of aviation photographing was calculated and revised. After this research, by using ortho aerial photos, We can understand efficiency of these in computing volumes of variations of coastline by analyzing quantitatively erosion and look of a heap. Besides, in the future, these will be used for information gathering of the coastline integration control system.

• Journal of the Korean Geographical Society
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• v.29 no.1
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• pp.84-104
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• 1994

The migration of population into the city has been on the increase according as Korea has been industrialized repidly since the 1960's. And there is a steady decrease in rural population. Thus lack of the number of the students forced many elementary Schools to be abolished. The aim of this study is to grasp the abolition types and the regional characteristics with the subject region of Chungbuk province. From the viewpoint of the increasing abolition of the elementary schools, I think it is very important to understand how the elementary schools have been abolished so far and predict how the subject region will have been changed in geography. Data for this study are based on Annual Establishment-Abolition Situation of the Schools published by Chungbuk office of Education in 1992, and many Kinds of the statistical reports, and the interview with the related. The results are as follows: 1. By examining the change of the number of the elementary schools and students in Chnugbuk, the numder of the students had also decreased since 1969 and was less than the half in 1990. As the number of the schools began to decrease ten years later than the students began to, the abolition of the elementary schools has started in reality from 1980's. 2. The 72 elementary schools were aboilshed between 1980 and 1992: the principal school is 9.7%, the branch school is 90.3%. The most fifteen schools are abolished in Yongdong-county and Chechon-county, and the least one school is abolished in Chechon-city and Okchon-county, and there is no abolition in Chongju-city and Chungju-city: According to the type of the abolition process, the least seven principal schools are abolished, and the principal school is reorganized as a branch school and twenty eight branch schools are abolished, and the most thirty seven branch schools are abolished. 3. When special change of the abolition is classified into the first perio (1980-1986) and the second period (1987-1992), in the first period the principal and branch schools were abolished and they are 13.9% of total abolition. The abolition out of them by building a dam is 60%. The principal schools in the submerged area though they have many students, were abolished. In the second period sixty two branch schools are abolished and they are 86.1% of total abolition. The most fifteen schools are abolished in Yongdong-county, thirteen in Chechon-county, seven in Tanyang-county, six in Chongwon-county, five in Chungwon-county and Koesan-county. Unlike the first period, the schools were abolished in this period because the number of students was so small. In this period sixty branch schools were abolished. All the students in the abolished schools except six schools transfered to the principal schools. The 58 school authorities help the students attend school by bus or support the expenses for attending school after that. 4. The abolition types of city, county and myon are classified into five types by the number of the abolished schools. The most forty nine abolished schools in type II are 68.1 of the total abolition. The least three abolished ones in type I are 12.5%. Considering the relation between the abolition type ane the number of schools and students, the number of the schools, increased in type I, II, III, V except IV from 1980 and then have decreased by abolition since 1980, while the more students decreased than they did in 1970 and the more the abolished school increases, the less the students decreases. The average students per school decreased in every abolition type and the most students decreased in type IV. 5. Considering the relation between the abolition type and the regional characteristics, most abolished schools were located between 100m and 300m above the sea level and it is 71% of the total abolition. The region without the abolition is high in the ratio of the cultivate land, ratio of rice field, and the part-time farmer, but the region with many abolition is low in the ratio of cultivated land. As for the manufacturing there are the most city, county and myon in the abolition type in Youngdong-county and Chechon-county where the manufacturing ratio of employing is low but Chongju-city without the abolition is a region where the manufacturing ratio is high. Consequently the development of the manufacturing causes the population to emigation out and the decrease of the population leads the transport is difficult of access, the facilities sold after being abolished are not being used in many ways. 7. Take an example of Youndong-county where the most schools were abolished, I have examined the school district and the population characteristics of the abolition. Though there were more villages, households, populations in the region that is higher than low above the sea level, the schools were abolished. Therefore we know that above the sea level had a great effect on the abolition. As a result of the regional analysis of the abolition, many schools were abolished by the artificial buildings such as a dam in the early 1980's but the schools in the late 1980's were abolished ten years later after the students decreased. More schools were abolished in the region where the manufacturing industry didn't develop. And the higher the school position was above the sea level, the sooner the school was abolished. It is also proved that both the beautiful natural scenery and accessibility are the important factor in using the abolished facilities practically.