• Journal of Wetlands Research
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• v.16 no.4
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• pp.477-486
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• 2014

Integrated sand control including sediment discharge from hinterland rivers is necessary to maintain coastal sand resources over a long term. In this regard, the following subjects should be considered; efficient ways to transfer discharged sand from a river to the neighboring coast, measures to improve storage efficiency of the discharged sand at the river delta and/or river terrace, measures to prevent the sand resources from being discharged into the deep sea during flooding. From the 1997 to January 2004, the jetty of 156 m length was constructed the Heoya-river mouth to protect the blockade of river mouth. Several tests were carried out to investigate the characteristics of sediment transport and morphological change due to the construction of the jetty at the Heoya-river mouth. Firstly, The sand discharge from Heoya river is quantified by one-dimensional numerical analysis assuming the mixed sand of three different particle diameters. Also the numerical mode system, which predicts the sea bed changes obtained from the Bailard's energy model(1981), was combined with the wave, wave-induced currents and sediment transport models. Then, to understand the changes to the blockade of the river mouth, several aerial photographs were compared, which showed that the changes were significant.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.315-321
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• 2008

Recently, in the light of environments and utilization, countermeasures to preserve beaches in coastal area are required without depending on such as jetties and breakwaters. The necessity of integrated sand management including not only coastal sediment but also sediment discharge from hinterland rivers is increased so as to establish long-term counterplan for sediment transport. In this regard, the following subjects are examined in this study; efficient ways for discharged sand to be transported from a river to the neighboring coast, the river terrace occurrence and its growth at the river delta, measures to improve storage efficiency of the discharged sand and measures to prevent the sand resources from being discharged into the deep sea during flooding. In recent, A jetty of 260 m length was constructed at Namdae River mouth in the year of 2005 as a countermeasure against the occurrence of sand-bar at river mouth and its close. In this study, a series of numerical experiments were carried out to investigate the characteristics of sediment transport and morphological change due to the construction of jetty at the entrance of Namdae River mouth. Firstly, The sand discharge from Namdae River is quantified by one-dimensional numerical analysis assuming the mixed sand of three different particle diameters. Then, in order to understand the transport behavior of the sand discharge from river and river mouth phenomena the numerical experiments were then conducted to examine the flow behaviors of river efflux and wind generated circulations in coastal area. And, after establishing the numerical model system, which predicts the sea bed changes obtained from the flux model combining with the wave propagation, wave-induced currents and sediment transport models, the sediment transport in the vicinity of Namdae River mouth is analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.64-73
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• 2018

The main purpose of this study is to assess the effectiveness of Meungri-Saju analysis concerning career counseling. Initially, we searched for 'fortune quality' of self-employed people whose works went out of business., We investigated what was weak or strong of 'fortune qaulity' because it gives you interests and talents as Holland says, and then we checked their one-year and 10-year personal circumstances, so called Saewoon, Deawoon that implies your own private circumstances as Super says. In addition to this, we exmained Woulgi because it predicts condition of change of the jobs. Study results were as follows: There were failed businesses that had serious weaknesses in wealth structures. In addition, Saewoon, Deawoon were terrible conditions because of Yongshin' Hap, Hyung, Chung. This study concluded that they had to be gone out of business. It is clear that you should check your wealth structure and Saewoon, Deawoon when you open your business. This study concludes that Meungri-Saju analysis is effective as a new model of career counseling.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.485-492
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• 2013

The point sand bars of Hahoi Village on Nakdong River have undergone considerable changes including fluvial and vegetation characteristics due to flood regulation by the dams constructed upstream. In this study, the numerical fluvial/sediment and water quality model, KU-RLMS, is applied to the aquatic area near Hahoi Village (middle/upper region of the Nakdong River) for clarifying the mechanisms of changes in hydraulic and aquatic characteristics. The fixed-bed hydraulic experiment was carried out for horizontal two-dimensional numerical model. The numerical simulation reveals that flow is accelerated near the left bank of Booyongdae downstream of the Hahoi Village area. Circulatory flow pattern was observed at the right bank downstream of Hahoi Village. The simulation was in good agreement with the hydraulic/physical experiment. For the discharge of design flood, at the area of circulatory flow pattern, the superelevation of about 1.0 m at the right bank was predicted compared to the left bank of high flow velocity, which is also in good agreement with hydraulic experiment.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.210-210
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• 2011

하도에서의 하천정비 및 안전하도 유지를 위해서는 하상변동 특성을 면밀히 파악하는 것이 중요하다. 상류유역에서 하천으로 내려온 유사(流砂)는 하천의 흐름과 생태환경에 영향을 미친다. 이중 하천흐름은 사련(ripple)이나 사구(dune)의 형성에 영향을 미쳐, 하천의 지형변동인 사주에 영향을 주고 하천 식생의 성장과 발달에 직 간접적으로 간섭하게 된다. 또한, 교량, 취수장의 취수장애, 호안블럭의 침식 등과 같이 수리구조물의 안정에 영향을 주게 된다. 하천의 유사량 변화에 따라 생태계의 서식환경이 변하게 된다. 또한, 저수지에서 유입 유사량의 변화에 따라 저수지의 용적이 변하게 되어 댐의 설계 및 운영에 많은 영향을 끼치게 되며 특히 저수지 탁수관리에 매우 중요하다. 본 연구에는 4개 대권역의 주요지천 및 댐 직 하류하천 지점 중 적정구간을 선택하여 하상재료조사를 실시하였다. 하상재료 조사는 하도를 구성하는 모래와 자갈의 물리적 성질 중 유사의 이동량 및 하상의 변동, 하도설계 등에 관련 있는 입도분포, 비중 등을 측정하며 자갈하천은 표층 하상재료를 조사하고, 모래 재료는 체분석, 실트이하 재료는 BW관 등을 이용한 침강속도 분석을 실시한다. 주요지점의 중 남강의 안의 수위 우량관측소 지점의 상 하류 2km 구간을 200m마다 21개 지점의 하상재료를 채취하여 입도분석을 실시하였다. 분석결과 남강 안의지점의 표층은 여느 하천과 마찬가지로 상 하류 굵은 자갈로 구성되어 있으며 전형적인 자갈하천의 특성을 보었다. 상류200m(2000m)에서는 최소 50mm(10mm), 최대 440mm(75mm), 평균입경은 174mm(34.7mm) 이었고, 하류200m(2000m)에서의 표층입경은 최소 8mm(25mm), 최대 50mm(110mm)이며 평균입경은 27.3mm(62.5mm)로 구성되어 있었다. 전체적으로 상류지역의 입경이 하류지역보다 큰 것을 관찰할 수 있었으며 유수 흐름의 일시적인 저항이 발생하는 안의교 지점의 자갈 입경이 인근 부근보다 큰 것을 확인할 수 있었다.

• Korean Journal of Remote Sensing
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• v.27 no.4
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• pp.403-410
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• 2011

Consistent observation with high temporal and spatial resolution is required for an efficient monitoring of coastal environments. Remote monitoring system installed on the ground is capable of simultaneous observation of wide coastal area and consistent observation with high frequency, which a small number of in-situ measurements cannot manage. This paper studies two typical ground based coastal monitoring system, marine radar and camera system. Marine radar can produce time series of frequency spectrum by integrating wave number spectrum calculated from spatial and temporal variation of waves in the radar image. The time averaged radar images of waves can analyze wave breaking zone, rip currents and location of littoral bars. Camera system can observe temporal variation of foam generation originated from coastal contamination as well as shoreline changes. By extracting the part of foams from rectified images, quantitative analysis of temporal foam variation can be done. By using the two above systems of different characteristics, synergetic benefit can be achieved.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.328-338
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• 2019

This paper presents the numerical simulations of future river bed changes using CCHE2D, a two-dimensional numerical model, for river confluences at the confluences of the Nakdong River and Gamcheon as well as Geum River and Mihocheon. The numerical simulations of future river bed changes were conducted for three years using hydrological data from August 30, 2012, to August 29, 2015 after the Four Major River Restoration Project. The simulation results demonstrated that river bed changes occurred actively near the confluence where sediment deposition was concentrated, resulting in the possibility of point bar formation. Through the numerical simulations, the characteristics of future river bed change was evaluated by investigating the characteristics of bed changes, average bed elevation changes, and the difference between deposition and erosion in the target section. The two-dimensional numerical model is expected to be used in the future to prepare effective stabilization plans for the tributary confluence.

• 한국노년학
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• v.29 no.1
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• pp.1-20
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• 2009

The purpose of the current research is to reconstruct the process in which changes in elderly support take place from the perspective of the elderly in rural areas. Six elderly couples were interviewed three times with the use of Schütze's 'autobiographical-narrative interview'. The entire interviews consisted of 17 sessions. Interviewed data was analyzed, following the method of Schütze's 'autobiographical-narrative interview analysis'. Research findings were as follows: Elderly support as experienced by the current elderly couples is mainly 'family support', which turned out to be 'dual structural shift' in the process of modernization. That is, there has been an 'internal structural shift' from 'family support on intergenerational, mutual support dimension' to 'family support on intragenerational self-support dimension' on the one hand. An 'external structural shift' has been noticed that realizes the 'socialization of family support' on the other hand. Additionally, a 'discrepancy' was captured between support norm and support behavior as occurred in the process of 'dual structural shift'. Perception on the 'dual structural shift' has proven 'ambivalent'. On the basis of these results, a critical discussion of modernization theory ensued, along with some implications for practice.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.250-257
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• 2023

Tree in river have environmental functions such as ecosystem preservation and flood control functions that protect the riverbank. On the other hand, excessive tree development can have the negative effect of fixing the sand bar and reducing the cross-sectional area. Nays2D simulation results performing two flow conditions (average dam operation discharge and two-year frequency discharge) and four tree density conditions (current, zero, low, high tree density) used as input data for PHABSIM to calculate WUA (Weighted Usable Area). The results show that riverbed changes occur more significantly in the zero tree density than presence of trees, which could have a positive impact on the biological habitat environment of Zacco platypus.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.897-908
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• 2008

황강에는 1989년 합천다목적댐과 본댐 하류 6.5km 지점에 조정지댐이 건설되었는데 조정지댐의 건설 목적은 본댐에서 피크 발전에 의해 방류되는 유량을 하류로 조절방류하기 위한것이다. 황강은 두댐의 건설후 하천폭, 하상재료, 식생 및 하천구간내 사주의 형성 등 많은 하천 지형학적 변화가 있었다. 이러한 변화는 댐 건설후 흐름 및 유사이송의 변화에 기인한다. 2002년 합천댐 저수지 퇴사량 조사에 의하면 합천댐은 연간 약 600천$m^3$의 유사를 차단한 것으로 파악되었다. 조정지댐은 연최대피크 방류량을 654.7$m^3/s$에서 126.3$m^3/s$로 감소시켰는데 이는 댐건설전의 19.3%에 해당하는 양이다. 댐건설로 인한 하류 하천의 지형적인 변화를 파악하기 위하여 합천조정지댐 하류로부터 낙동강 합류점까지 45 km에 대하여 조사하였다. 1982, 1993 및 2004년의 항공사진을 분석한 결과 비식생하도폭(non-vegetated active channel width)은 평균 152m 감소되었는데 이는 1982년의 약 53%에 해당한다. 비식생하도의 면적 역시 평균 6.6$km^2$가 감소하였다. 평균 중앙하상재료(D50)의 크기는 1983년 1.07mm에서 2003년 5.72mm로 증가한 반면 평균 하상구배는 1983년 0.000943에서 2003년 0.000847로 감소하였다. 총 하상 세굴깊이는 조정지댐 하류 20km 구간에서 평균 약 2.6m였다. 1차원 유사모형인 GSTAR-1D를 이용하여 예측된 최심하상고는 2013-2015년 사이 (댐건설후 약 25년 후)에 안정된 상태에 도달하는 것으로 나타났다. 합천 조정지댐이 본 댐에서의 피크 방류량을 상당히 감소시키고 있지만 홍수기에 조정지댐 수문의 급격하고 주기적인 개폐로 인하여 하류에 흐름의 펄스를 발생시키고 있다. 이러한 펄스가 하류 하천 지형변화에 미치는 영향을 파악하기 위하여 유사모형과 해석적인 방법을 개발 적용하여 구한 값과 비교 검토 하였다. 결과에 따르면, 일 흐름의 펄스(daily pulse)와 홍수피크(flood peak)는 각각의 평균값이 흐를 때와 비교하여 하천지형변화에 훨씬 큰 영향을 미치는 것으로 나타났다. 일 흐름 펄스와 홍수피크는 각각의 평균값의 21%와 15%의 토사 이송량 (tons/day) 증가를 보여주었다.