• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.1-11
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• 2004

An experimental study was carried out to investigate the influence of flow conditions of a boundary layer on the near-wake of a flat plate. Various attaching positions of tripping wires were selected to change flow conditions on a boundary layer. Laminar, transitional, and turbulent boundary layer conditions at 0.98C from the leading edge are imposed to investigate the evolution of symmetric and asymmetric wake. An x-type hot-wire probe(55P61) is employed to measure at 8 stations of the near-wake region. Measured mean velocity distributions are presented in terms of similarity parameter. It is found that the symmetric wake collapses well to the universal profile in the central part of the wake. However, the universal profile is not suitable in describing an asymmetric wake.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.61-64
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• 2005

The purpose of this paper is to take a closer look at an area having shorted emergence facilities and to determine optional candidate sites instead of vulnerable area by using GIS spatial analysis. Newly determined new candidate is performed by concerning spatial efficiency and spatial equity for a public service. It was determined through using the analyzing of the physical accessibility measure, the Location-Allocation, sort of classic model in spatial statistics and general network analysis. The area of this research has been used in administrative boundary of Young-Dong in Gangneung including 13 emergency, medical hospitals, 46 fire-stations and sub-fire stations. In general terms, what all this show is that the way we are approached for geographical view from using GIS spatial analyzing technique of determined location and allocation problem by the social, economical, political factor and simple administrative discrimination at the meantime. At the same time, with problem occurred in the space it is possible to make an Effective proposal or means, policy, decision for new candidate location-allocation suggesting optimum model.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1062-1068
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• 2009

Urban construction has numerous difficulties due to ground weakness and various complaints from third party, so it is not economically efficient and constructability is not favorable. Therefore, underground, which has good ground conditions, was used for construction field and facilities such as stations, and they are scaled up to enhance accommodation of facility limitation and function of stations. Large section tunnel station construction has numerous risk factors such as work boundary of excavation equipment, a relaxation of stress concentration, a safety plan of tunnel stability, and so on. Therefore, by using large section tunnel station stability analysis considering construction step, we expect to analyze the latent problem during construction, and to stabilize a future project plan of a large section structure design by using an auxiliary method and a support design.

• Water for future
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• v.14 no.3
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• pp.55-66
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• 1981

The theory and practice of water quality scoring and indexing are introduced. The monthly water analysis data are available for six stations long the down-stream Han River whthin the areal boundary of the Special City of Seoul. The data cover the period between 1975 and 1979 inclusive and contain the analytical findings on 37 water constituents including DO, BOD, temperature, total solids and etc. Sic parameters are selected form the 37 items, that, to the judgement of the writer, best reflect the water quality of the Han River. They are; dissolved oxggen saturation, pH, fecal coliform, total solids, BOD and nitrate+ammonia. For each of the six parameters, a subscore function is developed and graphically presented to facilitate the transform of a measurment of the arameter to a subscore on a common score(e.G. 0-100) The score of a sample is calculated as a fuction of the six subscores, using four different approaches; (1) the unweighted arithmetic water quality score, (2) the weighted arithmetic water quality score, (3)the unweighted multiplicative score and (4) the reduced (total) score. Independent of these calculated scores, the experts' score which is calculated by averaging the ratings of water quality experts is obtained and compared with each of the four calculated scores by means of the least square method. The experts' score compares most favorably with the "reduced" score with the correlation coefficient of 0.956 : therefore this method of water quality scoring is adopted to calculate the Han River water quality scores and indices. Water quality index data for Guiri, ukdo, Pokwangdong, Noryangjin, Yongdungpo and Kayang Stations, 1975-1979 are as follow: The overall water quality index data of the Han River between Guiri and Kayang Stations are found; 47.3 in 1976, 48.0 in 1977, 48.5 in 1978 and 54.7 in 1979, indicating the general trend towards water quality improvent in this part of the river, in terms of the increased water quality index by average 1.85 points per year during this period. Finally the optimum sampling frequencies distributed among the six stations, using an equation which takes into account the coefficients of variation of the water quality scores and indices arec calculated.alculated.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.1 s.1
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• pp.139-155
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• 2001

We investigate the vertical velocity models beneath the newly installed broadband seismic network of KMA (Korea Meteorological Administration) by using receiver function inversion technique. The seismic phases are primarily P-to-S conversions and reverberations generated at the two highest impedance interfaces like the Moho (crust-mantle boundary) and the sediment-basement contact. We obtained the teleseismic P-wave receiver functions, which were derived from teleseismic records of Seoul (SEO), Inchon (INCN), Tejeon (TEJ) , Sosan (SOS/SES), Kangnung (KAN), Ulchin (ULC/ULJ), Taegu (TAG), Pusan (PUS), and Ullung-do (ULL) stations. For Kwangju (KWA/KWJ) and Chunchon (CHU) stations, the Moho conversion Ps arrivals and waveforms of radial receiver functions are azimuthally inconsistent and unclear. From the receiver function inversion result, we found that crustal thickness is 29 km at INCN, SEO, and SOS (SES) stations, 28 km at KAN station in the Kyonggi Massif, 32 km at TEJ station in Okchon Folded Belt, 34 km at TAG, 33 km at PUS station in the Kyongsang Basin, 32 km at KWJ station (readjusted station by prior KWA station) included in the Youngdong-Kwangju Depression Zone, 28 km at ULC station in the eastern margin of the Ryongnam Massif, and 17 km at ULL station in the Ullung Island of the East Sea, respectively. The Moho configuration of INCN, SOS, KWJ, and KAN stations show a laminated smooth transition zone with a 3-5 km thick. The upper crusts(${\sim}5km$) of KAN, ULC, and PUS stations show complex structures with a high velocity. The unusually thick crusts are found at the TAG and PUS stations in the Kyongsang Basin compared to the thin (29-32 km) crust of the western part (INCN, SEO, SOS, TEJ, and KWA stations) The crustal thickness beneath Ullung Island (ULL station) shows the suboceanic crust with about 17 km thickness and complex with a high velocity layer of the upper crust, and the amplitudes of Incoming Ps waves from the western direction are relatively large compared to those from othor directions.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.124-135
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• 2007

The purpose of this study is to analyze the hydraulic behavior in a stream reach using SMS RMA-2 model with a series of dynamic boundary conditions of main stream and lateral flows simulated by WMS HEC-1 program. For the stream reach (10.5 km) between Gongdo and Pyeongtaek water level gauge stations of Anseongcheon, the model simulated two dimensional flow characteristics by applying dynamic flow conditions of rainfall frequencies of 50, 100, 500, and 1,000 years for the main stream and three tributaries. The temporal flow behavior successfully simulated and the results showed that the distribution of mean velocity and water level within the stream reach increased according to the increase of flow frequency. Especially, the flow velocity sensibly increased at the near downstream of lateral inflow as the width of main stream is narrower.

• Ocean and Polar Research
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• v.42 no.2
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• pp.97-113
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• 2020

In-situ observations were carried out in April 2015 to investigate the occurrence of water temperature inversion in a region west of Jeju Island. Analysis of in-situ in the western part of Jeju island showed that cold water moved to the southeast from the surface to the middle layer and warm water moved from the middle to the lower layer of the northwest direction. The water temperature inversion occurred at 84 stations (63.1%) out of 133 stations. At the boundary of the water temperature inversion layer, it was formed in the middle layer and disappeared. In the strongly appearing, it started from the middle layer to the lower layer. The shape of the water temperature inversion layer was different. As a result of horizontal water temperature slope analysis of the water temperature inversion zone, maximum 0.23℃/km was obtained and the mean was 0.06℃/km. The role of water temperature inversion as an indicator to determine the formation of water front. As a result of the water mass analysis, Jeju Warm Current Water and Tsushima Warm Current Water of high temperature and high salt intruded from the middle to the bottom. In the middle layer occurred as the Yellow Sea Cold Water of low water temperature and low salinity expanded.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.801-810
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• 2013

A field study was conducted to evaluate air quality from gas stations with and without Stage II vapor recovery systems that are currently used to reduce VOCs. The THC and VOCs levels were monitored for the test at three locations (inside office, around refueling area, site boundary) from a total of five gas stations. The results showed a considerable reduction in THC concentration which ranged from 48.7% to 81.8% with and without the operation of the Stage II VRS. Acoording to our comparative analysis, BTEX and other 19 VOCs levels were also significantly reduced with Stage II vapor recovery systems.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.2
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• pp.141-152
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• 2011

This study was investigated the species composition of demersal fishes by a bottom trawler GAYA, in order to be used basic data for resources management of fishery in the jointly controlled waters of the West sea. We caught 39 species, 5,532 individuals and 322.518kg in biomass. The number of species was the fewest of the jointly controlled waters of the East china sea and boundary zone between Busan and Tsushima. The first dominant species in individuals in summer was Oregonia gracilis, and in biomass was angler. But angler was the first dominant species in 7 stations of 12 stations. It was a peculiar phenomenon that cod which lives in a cold current was caught in the northern part of the West sea. In this connection it seems to be needs for oceanographic research. Catch per unit effort (kg/hr) of bottom trawl was the higher in northern part and in right line of all surveyed area respectively.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.70-81
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• 1997

The intesity survery on the 26 June 1997 Kyeongju Earthquake whose magnitude is 4.3, has been made for 316 locations throughout southen park of Korean Peninsula, then we have investigated the intensities distribution of the earthquake. Because the earthquake was occurred during night time (03:50:23.19), the most people who live farather than about 200km from the epicenter did not feel the earthquake. Therefore, the intensities are estimated only from IV to V in this study. The iso-seismal intensity map shows that the shape of iso-seismal intensity is similar to the boundary of the Kyeongsang Basin. This phenomenon may indicates that the energy of the earthquake is trapped within the Kyeongsang Basin due to low velocity within the basin compared with the velocity outside of the basin. The travel time curves with 10 possible phases are used to identify the earquake records. The Pg and Sg phases are crearly shown in the records whose epicental distance is less than 60 km. The records of MUN and PCH stations located outside of the Kyiongsang Basin show different frequency compared with that of the other stations located within the Kyeongsang Basin.