• International Area Studies Review
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• v.14 no.1
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• pp.33-53
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• 2010

This study has analysed riffle effect of shipbuilding business on regional economy in Jeonnam. For the analysis on connection to regional business, the most favored way to estimate economic effect of a certain industry in the nation and overseas, has been adopted. As a result of analysis, in case of 1,908,800 million won turnover in shipbuilding in Jeonnam, it would induce about 3,038,624 million won of production, about 940,656 million won of added value, about 13,361 employment and about 702,056 million won of income. Seeing production riffle effects of shipbuilding industry in Jeonnam on other businesses in the same area, it is found out to influence in order of on the primary industry metal products 458,784 million won, chemical products 128,250 million won, metal products 71,498 million won and on petrol and coal products 50,829 million won. Like this, shipbuilding industry is highly connected with metal and chemical industries, which make a cluster in eastern area of Jeonnam, suggesting that growth of shipbuilding industry in Jeonnam would maximize inter-industrial synergy effect in the region.

• Ecology and Resilient Infrastructure
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• v.4 no.2
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• pp.105-114
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• 2017

This study performed physical habitat simulation for fish and macroinvertebrate species in the Gongneung River. Target fishes were selected as Rhinogobius brunneus and Zacco platypus. Target macroinvertebrate species were selected as Hydropsyche kozhantschikovi and Chironomidae. Habitat suitability curves were constructed by using monitoring data from the monitoring project which is called "the survey and evaluation of aquatic ecosystem health". For calculation of CSI, weighted mean method was used. For macroinvertebrates species, the weighting factor derived from analytic hierarchy method was considered. River2D, which is capable to simulate flow in two-dimensional space, was selected for flow computation. Composite suitability index was simulated for target fish and macroinvertebrate species for discharge of drought, low, normal, and averaged-wet flow. Simulation results show that Chironomidae and Hydropsyche kozhantschikovi prefer the pool and riffle habitat, respectively. Rhinogobius brunneus and Zacco platypus show high suitability in riffle habitat.

• Korean Journal of Environment and Ecology
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• v.25 no.1
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• pp.71-80
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• 2011

The fish fauna and characteristics of population of Zacco platypus in the 9 microhabitat at the Tan Stream was investigated from August, 2009 to April, 2010. The collected species during the survey period were 17 species belong to 7 families. Korea endemic species were Hemiculter eigenmanni and Odontobutis interrupta, which showed a ration of 11.8% in collected species. Dominant species was Z. platypus and subdominant species was Carassius auratus. Dominated species of C. auratus was at the dam-type pool, Meander-type pool, run, and rock-type pool, Pseudogobio esocinus was side channel, Rhinogobius brunneus was riffle, and Z. platypus was channel connected pool, substrate-type pool and channel unconnected pool. Length-weight relationship in the population of Z. platypus was 3.29. PCA analysis was in to the 3 groups identified. Bary-curtis cluster analysis indicated that the substrate-type pool and channel unconnected pool 65.9% showed the most similar, riffle, and dam-type 30.4% were identified as the most contrast.

• Journal of Korea Water Resources Association
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• v.51 no.8
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• pp.713-727
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• 2018

This study is to develop an assessment system for stream physical environments by considering stream characteristics. Comprehensively, the descriptions of and steam classification, assessing reach selection, contents of assessment categories and indexes are summarized. Since the physical structure of stream is results of reaction by stream power, streams were classified into three types (as high gradient stream, mid gradient stream and low gradient stream) according to the slope of channel, the grain size of bed material and the characteristics of channel topography. The scale of assessment reach was selected based on 10 or 25 times of channel width according to typical characteristics such as interval of step or riffle and sinuosity in each stream type. The assessment indexes were organized into common indicators such as channel stability, flow status, cross-section shape, bank stability, channel alteration and stream crossing structure, and characteristic indicators by stream type such as effective habitats, bed embeddedness, diversity of flow and frequency of step or riffle. To evaluate the applicability, the assessment system was applied to 9 streams and the results were analyzed and presented.

• Journal of Environmental Science International
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• v.22 no.3
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• pp.309-318
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• 2013

This study was conducted for determining the influence of artificial structures on benthic macroinvertebrate communities in stream. Sampling was taken at upper(pool), down(riffle) and control(riffle) from two check dams, two weirs, one agricultural reservoir, and one multipurpose dam in northern part of Gyeongsangbuk-do. The benthic macroinvertebrate communities of these structures were surveyed during 2009 to 2011. The simple habitat of benthic macroinvertebrates occurred at the upper sites due to pooling effects from artificial structures. Specifically, Check dam1, Jusanji, Imha dam showed very low biological attribute values compared to the down and control sites, which have greater difference in substrate characteristics. However, in the upper sites of Check dam2, Weir1 and Weir2, the difference of values of biological attributes was relatively smaller. Also, proportion of functional feeding groups and functional habit groups were relatively simpler at upper stream and the degree of community differences was greater between upper and down, control sites. Spearman's correlation between biological attributes and substrate characteristics, water quality parameters had significant correlations; particularly, the substrate characteristics were more significantly related. In conclusion, the pool caused by artificial structures had negative effects on benthic macroinvertebrate communities thus leading to simplified stream habitats at upper stream ecosystems.

• Journal of Korea Water Resources Association
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• v.33 no.1
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• pp.3-14
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• 2000

The primary objective of this study is to estimate the suitable flow in need for conservation and restoration of the fish habitat in running water ecosystem, which has very important status in the instream flow for stream environment. Year, monthly low flows are estimated to properly maintain the fish habitat. Water depth and velocity are simulated, and also water temperature and Dissolved Oxygen(DO) are predicted at gradually varied flow using estimated low flows. These simulated conditions for each low flow are graphically compared with the requirements to maintain fish habitat at each life stage. These processes were applied to 3 riffle transects located at Dalcheon(Dal stream) in the South Han river. Pirami (Zacco platypus) was selected as a representative fish species in Dalcheon. It was shown that the suitable flow for maintaining the representative fish habitat at each life stage depends on hydraulic conditions rather than water quality conditions, and the flow ranges from the 10-year minimum low flow to consecutive 7-day 2.33-year low flow.w flow.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.791-799
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• 2019

This study explained the historical changes in the habitat structures based on the aerial photographs (1948, 1967, 1973, 1989 and 2010) of the mid-stream reach of the Mangyeong River. The habitat structure was divided into landforms and aquatic habitats. The landform was classified into bare land, vegetated land, water surface, farmland and artificial land. The aquatic habitat was classified into natural riffle, artificial riffle, run, head wando, tail wando, mid wando, pond and chute channel. The ratio of bareland decreased, and water surface and vegetated land increased after the excavation in 1970s and since the construction of weir in 1980s. As historical changes of aquatic habitat, ratio of run decreased sharply while mid wando increased sharply. aquatic habitats such as head wando, tail wando, and pond located on bars decreased dramatically.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.479-479
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• 2018

하천의 수심, 유속, 하상경사, 하상재료, 만곡도 등과 같은 물리적 특성에 따라 생물서식처로서 다양한 특성을 나타내고 그 특성들에 의해 서식처의 유형을 구분할 수 있다. 이러한 서식처 유형에 따라 수중음향의 특성이 달라지며, 수중음향의 서식지의 양적 표시자로서 잠재력으로 인해 최근 많은 연구들이 시도되고 있다. 본 연구에서는 인공적인 영향을 적게 받은 자연하천으로 양양 남대천 12개 지점을 대상으로 하여 서식지의 형태에 따른 수중음향과 하천의 수리적 인자에 따른 관계를 파악하고자 하였다. 서식처 유형으로는 빠른 유속에 얕은 수심을 가지고 있는 여울(riffle), 수심이 깊고 유속이 느린 소(pool), 낙차가 있는 계단형 여울(step riffle)에 대해 조사하였다. 수중배경음은 여울과 계단형 여울이 유사하게 나타났으며 소는 상대적으로 낮은 배경음을 나타내었다. H2, H4, H5, H9, H10 지점은 여울 형태로 유속에 따라 H2, H5, H4, H9 지점 순으로 음압레벨이 낮아지는 경향을 보였으며, H10지점은 H9, H4 지점에 비해 낮은 유속임에도 높은 음압레벨을 보였다. 이는 H10 지점의 하상이 조도가 매우 큰 전석으로 이루어져 나타나는 현상으로 판단된다. H3, H6, H7, H8, H12 지점은 소 형태로 H12 지점을 제외하고 대체로 낮은 음압레벨을 보였으며, H3과 H6지점에서는 저주파수에서 높은 음압레벨을 보였다. 이는 수심이 깊은 경우 상류의 저주파수의 음파가 잘 전달되기 때문으로 판단된다. H1과 H11지점은 계단형 여울로 낮은 수심에서 빠른 유속을 가진 H11지점과 느린 유속을 가진 H1 지점에서 대체로 높은 음압레벨을 나타내었다. 이는 낙차에 의한 수중음향 발생에 의한 것으로 판단된다. 세 가지 유형에 따른 수중 음향을 비교하였을 때 음압레벨은 계단형 여울, 여울, 소 순서로 높게 나타났다. 결과적으로 수중음향이 서식처의 수리적 특성에 따라 다양한 특성을 나타내고 있으며, 이를 통해 생물서식처를 평가하기 위한 새로운 방법으로 수중음향의 활용 가능성을 제시하였다.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.356-359
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• 2006

Dispute is construction itself. Serious difficulties ore occurred between contract parties when These disputes have occurred. Authority may fear the defective work if the requirement of contractor is fully reflected in the adjustment of contract. On the other hand the contractor may have fears that no payment or some payment of the extra work or the additional work done will be required. Therefore these problems must be resolved before these result in an enlarged riffle effect. To reduce the fear of the contract parties, ADR(Alternative Dispute Resolution) process were suggested.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.21-24
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• 2005

A by-product of construction can be easily reused through properly treatment. On the contrary, the level of technique to reuse the by-product is not so high. Especially, the bulky of trash concrete is huge. The demand and treatment cost of them is on the increase. So, the riffle effect of the recycle of the trash concrete cannot be bypassed. But the research on the recycle of them is few. Therefore, the reuse of recycled concrete, the treatment of them, and the promotion plan of them were suggested in this study