• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.169.2-169.2
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• 2010

Recently, the massive offshore bridges in a ship passage have been constructed on the sea. Therefore, the ship impact protection for the bridge-piers are installed to consider the possibility of vessel collision danger. Due to the ship impact protection, the flow-field characteristics are changed in comparison with the condition without the ship impact protection. Especially, the fluid velocity between the pier and the ship impact protection is possible to increase due to the contraction of the cross sectional area of flow. In this study, the tidal energy magnitude around the ship impact protection of Incheon bridge is assessed by simulating the flow-field by using FLOW-3D software.

• 한국경영과학회지
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• 제6권1호
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• pp.15-23
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• 1981

This paper deals with cross impact analysis for technology assessment. The focus of the paper is to develop new technique of cross impact matrix using goal programming method. In this study, the idea of cross impact analysis based on scenario generation method especially SMIC-74 (2) is expanded. Critical literature review on SMIC-74 is presented to discuss the mathematical rationale of consistent probability in cross impact analysis. A new model of cross impact analysis using goal programming to overcome the shortcomings of the scenario generation technique especially SMIC-74 is developed. This new technique is also applied to the assessment of the air pollution problems in Seoul Metropolitan area in Korea. The results of analysis give us following findings 1) Cross impact analysis using goal programming produce more meaningful solutions comparing to those of SMIC-74 2) Theoretical rationale of the objective function in the newly developed technique is more appropriate than that of SMIC-74.

• 환경영향평가
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• 제16권4호
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• pp.251-265
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• 2007

In this study, the influence of the construction of a large sized building on the flow and level of groundwater in a metropolitan area was investigated with simulation model MODFLOW for a selected area located in Gangseo-gu, Seoul, where a large business center was scheduled to be built. It was simulated that the groundwater level in the study area was suddenly lowered by the construction of a large building and groundwater in the surrounding area fast flowed into the study area. And even after the construction finished, the falling down of groundwater level consistently continued in some degree. The flow state of groundwater appeared to be the same in both cases where a soil cement wall is applied and where it is not during the construction. But for the case of application of a soil cement wall as the amount of groundwater flowing into the study site became reduced, it was estimated that the time for underground watershed getting far away from the site was also reduced and the influence of a building construction on the surrounding groundwater became reduced. Thus, it is deemed necessary that recharging the spilled ground water and rainfall into the construction area to lessen the abrupt change in flow and level of ground water should be considered in design of construction of a large sized building in a metropolitan area.

• 환경영향평가
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• 제4권1호
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• pp.65-78
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• 1995

The resident attitude for preservation and development of amenity in Eulsuk island and its downstream area at estuary of Nakdong river in Korea were investigated by the questionnaires and the field surveys. Based on the results, the characteristics of this study area are the natural ecological preservation area, natural environmental preservation area and curtural assets for migratory birds. And there are a estuary bank, a Dadae beach and a Molundae park. Special amenities are (1) the light (sunrise, sunset etc), (2) the water(river, sea etc.), (3) the air(fresh wind, beautiful sound etc.), (4) the land space(beautiful view, recreation field, reed area, pine forest etc.) and (5) the stream(dancing of migratory birds, water flow, folk dance, history remains etc.). But at present, the environmental qualities as health, aesthetics safety, amenity and culture are deteriorated by development. So the number of migratory birds are decreasing. The residents desired that in future this area be use for the recreation space, the park and the natural leaning fields etc, as well as the restoration of destroyed resources.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.293-296
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• 2002

The purpose of this study is to evaluate the hydrological impact due to temporal land cover change urbanization of Anseong-cheon watershed $(585.09km^2)$. WMS (Watershed Modeling System) HEC-1 was adopted, and burned DEM with $200{\times}200m$ resolution and soil map reclassified by hydrologic soil groups were prepared. Land cover for 1985, 1990, 1995 and 2000 were classified by maximum likelihood method, using Landsat MSS and TM imageries. Calibration and verification of HEC-1 were conducted using 4 storm events. Peak flow at Pyeong taek station increased $25.9m^3/sec$ during the past 15 years due to paddy and forest decrease. Streamflow impact by just paddy area decrease and forest area decrease were also analysed keeping watershed CN values unchanged of the given year, respectively.

• 한국환경과학회지
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• 제24권11호
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• pp.1473-1483
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• 2015

In this study, a digital terrain analysis had been performed for a mountainous watershed having wetlands. In order to consider the impact for wetland in the flow determination algorithm, the Laplace equation is implemented into the upslope accounting algorithm of wetness computation scheme. The computational algorithm of wetland to spatial contribution of downslope area and wetness was also developed to evaluate spatially distributed runoff due to the presence of wetland. Developed schemes were applied to Wangpichun watershed located Chuncuk mountain at Ulzingun, South Korea. Both spatial distribution of wetness and its histogram indicate that the developed scheme provides feasible consideration of wetland impact in spatial hydrologic analysis. The impact of wetland to downslope propagation pattern is also useful to evaluate spatially distributed runoff distribution.

• 환경영향평가
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• 제20권4호
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• pp.477-487
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• 2011

In this study, we deduced the best estimation methodology for amount of carbon sequestration by vegetation, through the case study using the data obtainable from the environmental assessment procedure. Our results showed that the estimation methodology using the national vegetation map was the best for the strategic environmental assessment, whileas those using the vegetation growth equation were applicable for environmental impact assessment procedure. Furthermore, we found that the amount of carbon sequestration by farmland and/or grassland, not by vegetation, was not negligible. Therefore, we concluded that the area of farmland and/or grassland need to be taken into account during the landuse planning.

• 환경영향평가
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• 제13권4호
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• pp.153-164
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• 2004

An integration study of time-variable small watershed and stream models (USEPA's SWMM and WASP5) was performed for impact assessment of urbanization on water environment. The study area, the Kyoungan Stream, the tributary of Paldang Lake, was divided into 111 subbasins, based on the topographic condition, land use, and drainage system. RUNOFF block of SWMM was applied to estimate runoff flow and quality. EXTRAN block computed daily and hourly flow according to simulated runoff flow, water supply, and drainage data. SWMM was connected to WASP5 by transforming output file of SWMM into input file of WASP5. The nonpoint source loads and flow data of SWMM were imported to WASP5. The stream was divided into 45 segments based on the watershed delineation. The study included three water quality parameters, BOD, TN, and TP. The validate models were used to examine the impact of urbanization on stream flow and water quality.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1686-1704
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• 2021

This study addresses the numerical simulation of the shield building of an AP1000 nuclear power plant (NPP) subjected to a large commercial aircraft impact. First, a simplified finite element model (F.E. model) of the large commercial Boeing 737 MAX 8 aircraft is established. The F.E. model of the AP1000 shield building is constructed, which is a reasonably simplified reinforced concrete structure. The effectiveness of both F.E. models is verified by the classical Riera method and the impact test of a 1/7.5 scaled GE-J79 engine model. Then, based on the verified F.E. models, the entire impact process of the aircraft on the shield building is simulated by the missile-target interaction method (coupled method) and by the ANSYS/LS-DYNA software, which is at different initial impact velocities and impact heights. Finally, the laws and characteristics of the aircraft impact force, residual velocity, kinetic energy, concrete damage, axial reinforcement stress, and perforated size are analyzed in detail. The results show that all of them increase with the addition to the initial impact velocity. The first four are not very sensitive to the impact height. The engine impact mainly contributes to the peak impact force, and the peak impact force is six times higher than that in the first stage. With increasing initial impact velocity, the maximum aircraft impact force rises linearly. The range of the tension and pressure of the reinforcement axial stress changes with the impact height. The perforated size increases with increasing impact height. The radial perforation area is almost insensitive to the initial impact velocity and impact height. The research of this study can provide help for engineers in designing AP1000 shield buildings.

• Computers and Concrete
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• 제21권5호
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• pp.583-592
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• 2018

Today, buildings are exposed to the effects such as explosion and impact loads. Usually, explosion and impact loads that act on the buildings such as nuclear power plants, airports, defense industry and military facilities, can occur occasionally on the normal buildings because of some reasons like drop weight impacts, natural gas system explosions, and terrorist attacks. Therefore, it has become important to examine the behavior of reinforced concrete (RC) structures under impact loading. Development of computational mechanics has facilitated the modeling of such load conditions. In this study, three kinds of RC walls that have different geometric forms (square, ellipse, and circle) and used in guardhouses with same usage area were modeled with Abaqus finite element software. The three configurations were subjected to the same impact energy to determine the geometric form that gives the best behavior under the impact loading. As a result of the analyses, the transverse impact forces and failure modes of RC walls under impact loading were obtained. Circular formed (CF) reinforced concrete wall which has same impact resistance in each direction had more advantages. Nonetheless, in the case of the impact loading occurring in the major axis direction of the ellipse (EF-1), the elliptical formed reinforced concrete wall has higher impact resistance.