• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.101-109
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• 2008

Several numerical models for predicting beach profile changes have been developed by many researchers. Many of the earlier models are known to simulate the erosional profiles with the formation of offshore bar. However, most of the models don't have proper mechanism to incorporate the recovery process of the eroded profiles after a storm and can not simulate the beach accretion with acceptable accuracy. In order to overcome these shortcomings, we propose a new numerical model which has new features to simulate the accretional phase of beach recovery process after storm including such as redistribution of suspended sand particles near the breaking point. The simulation results of the proposed model were compared with LWT (Large Wave Tank) experiments performed at CRIEPI (Central Research Institute of Electric Power Industry in Japan) and CE (the Us Army Corps of Engineers) and it was shown to have performed better compared to SBEACH (Storm-induced BEAch CHange).

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.102-108
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• 2010

The internal structure of a river embankment must be delineated as part of investigations to evaluate its safety. Geophysical methods can be most effective means for that purpose, if they are used together with geotechnical methods such as the cone penetration test (CPT) and drilling. Since the dyke body and subsoil in general consist of material with a wide range of grain size, the properties and stratification of the soil must be accurately estimated to predict the mechanical stability and water infiltration in the river embankment. The strength and water content of the levee soil are also parameters required for such prediction. These parameters are usually estimated from CPT data, drilled core samples and laboratory tests. In this study we attempt to utilise geophysical data to estimate these parameters more effectively for very long river embankments. S-wave velocity and resistivity of the levee soils obtained with geophysical surveys are used to classify the soils. The classification is based on a physical soil model, called the unconsolidated sand model. Using this model, a soil profile along the river embankment is constructed from S-wave velocity and resistivity profiles. The soil profile thus obtained has been verified by geotechnical logs, which proves its usefulness for investigation of a river embankment.

• Journal of the Speleological Society of Korea
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• v.3 no.3
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• pp.46-46
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• 1978

한국중앙문화부로부터 7~8년전에 부사산용암동혈연구회에 기증된 제주도의 $\ulcorner$용암동굴$\lrcorner$의 부도인 측량도에는 평면도 밖에 기재되어 있지 않았다. 이것은 일본과 마찬가지로 한국에 있어서도 종전까지 주로 종유동굴에만 관심이 있었기 때문일 것이다.(중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.10b
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• pp.89-93
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• 2000

광파장 및 조사시기에 따른 오이묘의 생육 반응을 검토하였다. 광원에 따른 오이 묘의 생육상태를 조사해본 결과 청색광, 적색광을 처리한 것이 생체중, 하배축 무게, 근중이 증가하면서 하배축의 신장이 억제되었고, 청색광과 적색광을 혼합하여 야간 12시간씩 조사하여 30일간 육묘해 본 결과 뿌리의 발육도 우수하고, 줄기와 잎의 생육 정도에서도 우량묘의 소질을 보였다. 청색광과 적색광을 혼합하여 야간 6시간과 12시간씩을 조사하여 30일간 육묘한 결과 하배축의 길이는 각각 60.0mm와 44.9mm였고, 하배축의 무게는 0.59g, 0.62g으로 나타나 12시간 조사구가 하배축의 신장억제효과가 큰 것으로 나타났다. 하배축의 엽록소 함량은 청색광과 적색광의 조사시간이 길어질수록 뚜렷이 증가하였고, 식물체도 진한 녹색을 나타냈다. 광처리구와 무처리구의 오이묘 하배축의 횡단면과 종단면을 검경하여 세포구조를 비교해 본 결과 광처리구의 횡단면 표피조직은 단층의 밀착된 세포로 되어 있으며, 바깥쪽 세포는 현저하게 두꺼웠다. 후각조직의 세포는 작고 부정형이며, 세포간극이 조밀하였으며, 세포구조도 치밀한 특성을 보였다. 종단면은 광처리구에서 세포가 짧고 세포간에 간극이 없는 반면 무처리구는 세포가 길고 뚜렷이 구분되지 않은 것이 관찰되어 대체로 광처리구는 무처리구에 비해 세포신장이 억제되는 대신 세포구조가 치밀하여 식물체의 도장이 억제된다는 것을 알 수 있었다.

• Journal of Wetlands Research
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• v.11 no.2
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• pp.89-98
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• 2009

This study determines the stream mean slope, stream slope and longitudinal stream profile based on the concept of informational entropy. Maximizing the entropy will make the probability distribution of longitudinal stream profile as uniform as possible while satisfying the constraints. Using this relationships the mean stream slope, stream slope and longitudinal stream profile formulas were derived. The parameters of the applied streams were estimated by the least square method using the geomorphological factors of Dalchon stream basin obtained from Chungcheong Buk-Do local stream consolidation scheme drawings. The comparative investigation was performed between the observed and simulated mean stream slope and longitudinal stream profile, and are in good agreement with the measured data. It is noted that this results can be used in the estimation of stream mean slope and longitudinal stream profile.

• Journal of Industrial Convergence
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• v.20 no.5
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• pp.21-28
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• 2022

Unlike previous studies, this study looked at the effect of the ideological tendencies of local government heads on the social welfare budget as a longitudinal study. This study was made possible by the election of the head of a progressive group in Gumi-si, a stronghold of conservatives, after the implementation of the local self-government system. Therefore, in this study, the change process of the political ideological orientation of Gumi-si's heads and the social welfare budget by year were listed and time-series analysis was conducted using actual cases of Gumi-si, Gyeongbuk for more than 12 years. As a result of the analysis, first, as in the cross-sectional analysis, in the longitudinal study, the change in the rate of increase in the social welfare budget according to the political ideological tendencies of the head of the local government showed a meaningful difference. Second, as in the previous cross-sectional analysis, the social welfare budget increased in the year before the election. Third, the same change in the growth rate as in the second did not appear at the end of the third elected term. All studies on the relationship between the political ideological tendencies of local government heads (including local councils) and the social welfare budget have been cross-sectional. However, this study has great implications in terms of the results of the first longitudinal cross-sectional analysis.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.147-158
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• 2015

In this study, sewer backfill material was developed to prevent sewer damage and ground subsidence. Laboratory test was performed in the field of CA replacement ratio, accelerator type and replacement ratio and W/M. The compression strength of backfill material was 0.55~0.64MPa below in W/M 70% and 0.20MPa over W/B 80%. Ice block was used to simulate the ground cavity and subsidence caused by sewer damage in application study. The existing sand compaction and the new backfill material was comparative estimated in field. The ground settlement of cross section was 23.4cm and that of longitudinal section was 27cm in sand compaction section, but the ground had not sunk in backfill material section.

• Journal of Korea Water Resources Association
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• v.43 no.5
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• pp.421-431
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• 2010

The hydromorphological structure assessment of the urban streams of Anyang stream, Yangjae stream, Osan stream, Jangsu stream, and Hakui stream 5 years the after close to nature stream restoration work was performed using LAWA (Laenderarbeitsgemeinschaft Wasser) for the investigation of the ecology of streams in urban areas. Based on the results, the effectiveness of stream restoration in urban areas was least in spite that existing various types of stream improvements were applied. Significantly, the grade of the longitudinal, the waterfront, and the use of land nearby waterfront was poorly evaluated. It would be estimated that this trend was due to the discontinuity of the longitudinal, the lack of diversity in waterfront, the installation of facilities nearby waterfront, and was due to the use of hard materials as like stones, blocks, frames, and mats in waterfront. The further studies on the implementation of structural diversity in waterfront should be performed for the improvement of the ecology of urban streams.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2098-2102
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• 2009

본 연구에서는 국내에서 자연형 하천의 복원이 이루어진지 5년 이상이 된 도시지역의 하천을 LAWA(Laenderarbeits-gemeinschaft Wasser = 연방물관리연구공동체)(2000)를 이용하여 하천의 물리적 구조를 평가하였다. 물리적 구조 평가에서는 하천의 종적특성 및 종단면, 횡단면, 하상구조, 하안구조 및 하천변의 토지 이용성 등 6개항의 25개 세부항목으로 구성된 하천의 자연성과 하천의 인공성 정도를 가늠하였다. 그 결과 기 조성된 국내의 하천의 생태성이 크게 개선되어지지 않았음을 알 수 있었다. 이러한 결과를 근거로 볼 때에 과거의 자연형 하천 조성방법에 대한 근본적인 문제점을 살펴보고 개선책을 찾아야할 것으로 사료된다. 특히 도심하천의 경우 이, 치수의 기능 위주로 정비가 되어 있었기 때문에 자연형 하천으로의 복원 후에도 주변의 좋지 않은 구조물들에 의해서 물리적 등급이 낮게 평가되었다. 따라서 앞으로 하천 스스로 생태성, 자연성을 회복할 수 없는 구간에 대한 하천설계에서는 물리적 구조 향상을 위한 적극적인 방안이 시도 되어야 할 것으로 사료된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1098-1104
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• 2011

This paper presents the development of the surface profile sensing system (SPSS) and its application to analysis of road surface. The SPSS which can robustly reconstruct the road input profiles from the intermixed data with the vehicle's dynamic motion, is implemented using the multi-sensor system with the optimally shaped transfer function. The performance of this system is evaluated by a series of experimental works in the devised simulator. And a real car test equipped with the proposed system is performed in the proving ground over both deterministic and random road surfaces. Finally, a feasibility of the system is investigated considering the road model.