• Journal of the Korean Geotechnical Society
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• v.18 no.3
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• pp.87-94
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• 2002

Recently, there have been numerous attempts to expand the traditional temporary soil nailing system into a permanent wall. Two reasons for this include the soil nailed system's advantage of efficient and economic use of subgrade space and its ability to decrease the total construction cost. However, the systematic and logical design approach has not been proposed yet. The permanent soil nailing wall system, which utilizes precast concrete from soil nailing system, is already used in many countries, but the study of cast-in-place concrete lacing or rigid walls in bottom-up construction of traditional soil nailing walls is imperfect and insufficient. In this paper, various laboratory model tests have been carried out to investigate the influence of parameters, including stiffness of the rigid wall to the soil nailing structure with respect to failure mode, displacement patterns and tensile forces at the nail head in several levels of load. Then, the variation of earth pressure distribution on the soil nailing wall, built with a rigid front plate, is sought through different levels of surcharge load and tensile forces at the nail head.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.83-91
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• 2017

In case of estimation of settlement for the piled-raft foundation, it is necessary to consider interaction among raft, piles and soil. But, simple analytic methods usually are not applicable to considering this complicated interaction. In this study, a computer-based approximate analytic method, HDPR, was developed in consideration of above mentioned interaction in order to analysis of settlement for the piled-raft foundation. The finite element method was applied to raft analysis by means of the Mindlin plate theory, and soil and piles were modeled as springs which were connected with their raft. The linear spring which can consider multi layered soil and the non-linear spring were applied to soil springs and pile springs, respectively. The raft-piles-soil interaction was reflected to each spring. In order to verify the developed analytic method, it was compared and analyzed with 3D FEM analysis, existing approximate analytic method and site monitoring data. As a result, the developed analytic method showed reasonable results of settlement estimations of raft and piles for each case. From a practical point of view, it is confirmed that this analytic method is able to apply for analysis and design of the piled-raft foundation.

• The KIPS Transactions:PartA
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• v.11A no.5
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• pp.355-364
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• 2004

These days, various clustering technologies have been adopted to construct web sites. High performance hardware switches have good performance, but have disadvantage of high cost for constructing small and middle-sized web sites. Now a days, many sites have been constructed with the LVS (Linux Virtual Server), which is free of charge and has good performance. Having a centralized load balancing with one front-end, the LVS causes a bottleneck when it receives all at once. In the paper, we suggest a way to remove the LVS bottleneck by providing multiple front-ends. In this architecture, all of cluster nodes act as both a front-end and a back-end. When the load of a node receiving requests is not large enough, the node responds to the client directly. When the load of a node is large enough, the node send the request to a node which is selected by a scheduling algorithm. The scheduling algorithm is discussed to balance loads between servers. While single front-end cluster raises the throughput curvedly, the multiple front-end cluster raises the throughput linearly.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.186-192
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• 2005

We investigated the deposition characteristics and mass transport flux estimation of the Nakdong estuary, Korea. To understand the effects of the tidal current circulation that influences estuary terrain changes, we used a 2D numerical model to map seawater circulation under three different situations, with the level of river flow being set as none or flood. The net-water flux of the cross-sectional area between sandbars (known as dung) was estimated. From our review of previous research, we know that the development of local sandbars shifted from the west to the east side of the estuary after the construction of the Nakdong River dike. Current development is occurring mostly at the Bakhap-dung near Tadea. The seawater circulation pattern over this large-scale area of tidal na is brings changes related to the quantity of the outflow from the Nakdong River. Based on the calculated results for the net-water flux of the cross-sectional area, we see very strong accumulation in local waters around Jangjiado, Bakhapdung, and Tadae under flood river flow conditions, but accumulation in local waters around Jinudo under the other states of flow. Consequently, in the Nakdong estuary, the main sensitive regions that are affected by changes in the flow of river discharge are the local waters around Jangiado, Bakhapdung, Tadae, and Jinudo.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.543-548
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• 2017

The aim of this study was to evaluate anteroposterior oblique(RPO, LPO) and posteroanterior oblique(LAO, RAO) projections of the cervical spine, at various kVp and mA s increments, in order to compare thyroid surface dose. Using Rando phantom, dosimeter was attached to the Cervical spine 4~5 to measure the surface dose in the same thyroid position. As a result, the surface dose was $595.08{\pm}215.01{\mu}Gy$ for anteroposterior oblique(RPO, LPO) projections and $64.21{\pm}33.49{\mu}Gy$ for posteroanterior oblique(LAO, RAO) projections by changing kVp increment. The surface dose was $445.20{\pm}230.90{\mu}Gy$ for anteroposterior oblique(RPO, LPO) projections and $44.51{\pm}22.77{\mu}Gy$ for posteroanterior oblique(LAO, RAO) projections by changing mAs increment. The posteroanterior oblique method could reduce about 90% the surface dose than the anteroposterior oblique method. There were statistically significant differences among the examinations(p<0.001). Change the direction of position to reduce the surface dose at oblique projection of cervical spine. Therefore, we consider posteroanterior oblique projections than anteroposterior oblique projections of cervical spine examination in other to reduce patient surface dose.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.4
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• pp.251-256
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• 1976

Langmuir adsorption maximum was used as a basis for the estimation of phosphate requirement as related to the application method to a newly reclaimed hilly land. The application rates of phosphate fertilizer were 4 levels corresponding to 5, 10, 20, and 30 percent of the Langmuir adsorption maximum which was determined by the laboratory experiment. The phosphate fertilizer was applied in two different methods of broadcast and band application. Yield of soybean on a newly reclaimed hilly land was greatly affected by the amount of phosphate fertilizer and application method. With the same amount of phosphate fertilizer, the soybean yield in the broadcast was always lower than that in the band application even though the yield in the broadcast increased with the application rate up to the highest level of this experiment. However, the yield in the band application showed steep increase up to 20 percent level and then the yield decreased at the highest level. The yield at the rate of 5 percent with the band application was equal to the yield at the rate of 20 percent with broadcast, and the yield at the rate of 10 percent with band application was higher by 17 percent than that in the highest broadcast rate. When manure was applied at the rate of 1000 kg/10a to the plot of the 10 percent band application, the yield was 14.6 percent higher than the yield of the plot of the 10 percent band application without the manure and was equivalent to the yield of the plot of the 20 percent band application.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.142-149
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• 2019

In this study, the past erosion history and current status in the CHUNG-UI beach of Eulwang-dong, Jung-gu, Incheon-Si, South Korea were investigated and analyzed the wave with wave-induced current to investigate the causes of coastal erosion. As a result, the significant wave height ($H_{1/3}$) was in the range of 0.07~1.57 m and the mean value was 0.21 m. The maximum wave height ($H_{max}$) was in the range of 0.02-4.76m and the mean value was 0.27m. The vertical wave height and cycles were estimated through numerical model experiments of wave transformation. The 50-year frequency design wave height ranged from 0.82m to 3.75m. As a result of the experiment of wave-induced current, wave-induced current in the CHUNG-UI beach was decreased after the installation of the Detached breakwater and the Jetty. On the other hand, when the crest elevation was increased up to 5 m, there was no significant change, but when the crest elevation was increased to 8m, strong wave-induced current occurred around the submerged breakwaters due to lowered depth of water. In addition, the main erosion of the CHUNG-UI beach is due to the intensive invasion of the wave characteristics coming from the outer sea into the white sandy beach. The deformation of the wave centered on the front of the sandy beach caused additional longshore currents flowing parallel to the sandy beach and rip currents in the transverse direction, thus confirming that the longshore sediment was moved out of the front and out of the sea. The results of this study can be used as preliminary data for the recovery of the sand and the selection of efficient erosion prevention facilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.477-484
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• 2019

As the residence time in the vehicle increases, the passenger desires a pleasant and stable riding environment in addition to the high driving performance of the vehicle. The windshield defrosting performance is one of the performance requirements that is essential for driver's safe driving. In order to improve the defrosting performance of the windshield of a vehicle, relevant elements such as the shape of the defrost nozzle should be appropriately designed. In this paper, CFD based numerical analysis is conducted to improve defrost performance of small electric vehicles. The defrost performance analysis was performed by changing the angle of the defrost nozzle and the guide vane that spray hot air to the windshield of the vehicle. Numerical simulation results show that the defrosting performance is best when the defrost nozzle angle is $70^{\circ}$ and the guide vane installation angle is $60^{\circ}$. Based on the analytical results, the defrosting experiment was performed by fabricating the defrost nozzle and the guide vane. As a result of the experiment, it is confirmed that the frost of windshield is removed by 80% within 20 minutes, and it is judged that the defrost performance satisfying the FVMSS 103 specification is secured.

• Journal of Radiation Protection and Research
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• v.39 no.1
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• pp.21-29
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• 2014

A new cold neutron triple-axis spectrometer (Cold-TAS) was recently constructed at the 30 MWth research reactor, HANARO. The spectrometer, which is composed of neutron optical components and radiation shield, required a redesign of the segmented monochromator shield due to the lack of adequate support of its weight. To shed some weight, lowering the height of the segmented shield was suggested while adding more radiation shield to the top cover of the monochromator chamber. To investigate the radiological effect of such change, we performed MCNPX simulations of a few different configurations of the Cold-TAS monochromator shield and obtained neutron and photon intensities at 5 reference points just outside the shield. Reducing the 35% of the height of the segmented shield and locating lead 10 cm from the bottom of the top cover made of polyethylene was shown to perform just as well as the original configuration as radiation shield excepting gamma flux at two points. Using gamma map by MCNPX, it was checked that is distribution of gamma. Increased flux had direction to the top and it had longer distance from top of segmented shield. However, because of reducing the 35% of the height, height of dissipated gamma was lower than original geometry. Reducing the 35% of the height of the segmented shield and locating lead 10cm from the bottom of the top cover was selected. After changing geometry, radiation dose was measured by TLD for confirming tester's safety at any condition. Neutron(0.21 ${\mu}Svhr^{-1}$) and gamma(3.69 ${\mu}Svhr^{-1}$) radiation dose were satisfied standard(6.25 ${\mu}Svhr^{-1}$).

• Vending industry
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• v.2 no.5 s.6
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• pp.56-62
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• 2002

담배자판기의 신규설치를 금지하고 기존 설치된 자판기마저 전면철거하도록 하는 보건복지부의 초강력 규제안이 마침내 철회가 되게 되었다. 보건복지부는 올 들어 확대되는 금연정책에 편승, 기존 흡연 구역 내 담배자판기 신규설치를 금지하고, 기존 설치된 제품들마저 전면철거하는 규제를 담은 국민건강증진법 시행령 개정안을 지난 4월 공고하며 그 입법추진을 진행한 바 있다. 이 공고안은 그간 국무총리실 산하 규제개혁위원회 분과위원회에 상정되어 1,2차 심의를 진행해 오다 지난 9월 27일 본회의를 통해 '보건복지부의 흡연구역 내 담배자판기 신규설치 금지 및 기존 자판기 철거는 명백히 영업활동 자유 및 재산권 침해에 해당된다.'는 이유로 이를 철회토록 하는 결정을 진행했다. 이 결정을 담은 국민건강증진법 개정안은 조만간 법제처 심사 및 차관회의 등을 거쳐 최종 확정 되게 된다. 이같은 규제개혁위원회의 결정은 협회를 중심으로 한 산업의 적극적인 대응이 있었기에 가능했다. 성인인증장치 도입을 통해 청소년 흡연문제를 완전, 해결하겠다는 산업계의 적극적인 자율대책에도 불구하고 아예 담배자판기를 뿌리 채 뽑겠다는 보건복지부의 행정만능주의적인 발상은 도저히 수용하지 못할 부당한 처사라는 데 관련업계가 인식을 같이 했다. 따라서 이를 반대하는 산업계 입장을 분명히 하며 분명히 하며 적극적인 저지 대응을 최근까지 진행해 왔다. 협회에서는 1차적으로 보건복지부 건강증진과에 담배자판기 전면철거에 대한 산업계 반대 입장을 피력하는 소견서 제출하고 적극적인 산업계의 반대의지를 피력하는 작업을 진행했다. 또한 청소년보호위원회를 통해 청소년 흡연감소를 위한 성인인증 담배자판기 설치 활용방안 건의하며 담배자판기의 긍정적인 활용측면을 집중 부각시키기도 했다. 재정경제부를 통해서는 담배사업법 관련 담배자판기 설치기준에 대한 질의를 통해 현행 관련법 내에서의 설치기준을 명확히 하기도 했다. 이같은 대응에 있어서의 핵심 설득 논리는 담배자판기가 이제는 성인인증장치 부착을 통해 청소년 및 사회적 위해 요인을 극소화 할 수 있다는 점에 있었다. 과거와는 달리 담배자판기가 오히려 청소년의 담배 구입루트 차단이라는 긍정적 역할을 할 수 있는 시점에 있어 이를 전면규제하기보다는 합법적인 설치 환경을 확보하여 사회적으로 떳떳하게 존재가치를 평가받을 수 있게 해달라는게 산업계의 초지일관의 주장이었던 것. 협회는 이같은 주장이 결코 산업계의 이기만이 아니라 세계적인 추세라는 점, 또 담배자판기를 전면철거까지 하면서 과당규제를 할 명분이 부족하다는 점을 반대논리로 적극 내세웠다. 규제개혁위원회가 이번 공공 이용시설 중 흡연구역으로 지정된 장소 내에 담배자판기는 설치 금지 및 철거규제에 철회권고를 내리게 된 것은 이러한 산업계의 주장을 적극 수용함에 힘입은 바 크다. 규제개혁위원회는 이번 결정의 주된 이유로 우선 기설치된 자판기에 대한 철거는 재산권 침해로 위헌 소지가 있음을 들고 있다. 또한 흡연자를 위한 흡연구역내에서마저 자판기 설치를 금지하는 등의 규제는 과도하며 흡연자의 권익보호 역시도 필요함을 인정하고 있다. 따라서 전면적인 규제보다는 청소년 이용통제 가능한 흡연구역에 한하여 담배자판기를 설치토록한 현행규정의 실질적 관리를 강화하며, 전체적으로 흡연구역을 축소 제한하는 방향으로 추진함이 바람직하다는 의견을 제시했다. 규제개혁위원회의 이번 결정으로 흡연구역 내 담배자판기의 설치는 현행법의 적용을 받게 되며, 산업계의 자율대책대로 성인인증 장치를 부착한 담배자판기의 설치 확대가 크게 촉발될 수 있을 것으로 기대된다. 담배자판기가 적극적이고 능동적인 사회적 역할을 할 수 있을 때 자연 이를 반대할 수 있는 명분도 약해질 수 밖에 없다. 산업계는 보다 신뢰성 있게 청소년 이용을 차단할 수 있는 담배자판기 관련 기술 수준을 향상시켜야 할 것이며, 협회에서는 담배자판기의 공공성과 역할에 대한 지속적인 계몽 홍보를 통해 소비자 인식을 고양시켜 나갈 수 있게 해야 할 것이다. 비록 전면 규제 완화가 어렵고 힘든 길이기는 하지만 소비자에게 신뢰성을 부여하고 청소년의 담배 구입 루트 차단에 혁혁한 역할을 다할 수 있게 된다면 그 입지기반을 재평가 받을 수 있게 될 것이다. 담배자판기의 내일은 이제 암울함이 아닌 서서히 희망을 비치는 쪽으로 급선회되고 있다.