• Animal cells and systems
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• v.16 no.1
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• pp.69-76
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• 2012

This study was conducted to examine how a low-head dam removal (partial removal) could affect benthic macroinvertebrate communities in a stream. Benthic macroinvertebrates and substrates were seasonally sampled before and after dam removal (March 2006-April 2007). Benthic macroinvertebrates and substrates were quantitatively sampled from immediately upstream (upper: pool) and downstream (lower: riffle) sites, the location of the dam itself (middle), and immediately above the impoundment (control: riffle). After the removal, species richness and density of benthic macroinvertebrates as well as the EPT group (Ephemeroptera, Plecoptera and Trichoptera) increased to higher levels than those before the removal, while functional feeding groups and habitat orientation groups changed more heterogeneously at the upper site. At the lower site, species richness and density decreased somewhat immediately after dam removal, which was associated with an increase of silt and sand, but recovered after monsoon floods which helped to enhance substrate diversity at the upper site. Decreased dominance index and increased diversity index in both the upper and lower sites are evidence of positive effects from the dam removal. In conclusion, we suggest that even a partial removal of a dam, resulting in increased substrate diversity in the upper site, could sufficiently help rehabilitate lost ecological integrity of streams without major habitat changes.

• 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.

• 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 the Korean Society for Aeronautical & Space Sciences
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• v.44 no.2
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• pp.189-194
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• 2016

This paper deals with the economic effects for the Surion(KUH-1) research and development program. The economic effects was measured by Inter-industry analysis method for production-inducing effects, value-added inducement effects, and job-creation effects and by estimating actual domestic input cost. In addition, technical riffle effects was analyzed for aerospace industry, defense industry and commercial industry market through similarity and contribution of technology.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.751-753
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• 1995

Practical controllers of industrial systems are usually designed and realized in continuous time domain. However, due to the programmable and flexible nature of digital computers and the speed and stability superioity of digital components over analog ones, it seems more effective to adapt digital controllers. When an existing analog controller performs satisfactory, it is often advantageous to use the digital redesign techinque to obtain an equlivalent digital controller which substitutes the analog one. One method of the digital redesign is to use a periodic gain. This method gives a riffle effect on the steady state response, although it's transient response is satisfactory. This paper suggests a method which eliminates or deminishes periodic ripples generated by the periodic function.

• Journal of Environmental Policy
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• v.10 no.3
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• pp.49-71
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• 2011

Water is an essential element required for the survival of 6 billion human beings around the world, and it has limited mobility. The importance of water industry has grown considerably, as its forecasted market size is expected to increase from $336 billion in 2007 to $865 billion in 2025, respectively. In 2003, the domestic water market was estimated to be worth 11 trillion won. However, according to the estimates of this research, the result above was overestimated by 2 trillion won. The economic ripple effects of newly defined water industry based on the input-output data from 2000 to 2008 were trivial, as the price effects of water industry was considerably minor at only 0.12%. To successfully implement policies to enhance the water industry, the market price mechanism must operate and function properly. Nevertheless, the impact of water's market prices on the economy upon application is projected to be trivial.

• Journal of Environmental Policy
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• v.14 no.2
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• pp.3-25
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• 2015

Our goal is to verify how changes in water's hydraulic characteristics after urban regeneration stream can affect any possible transformation of its thermal environment. To that end, we analyzed changes in numerous physical characteristics the subject stream along with the meteorological factors and thermal environment affected by it. Cheonggyecheon was selected as our subject as it is a great example of successful urban regeneration stream. As for physical characteristics, we allocated Type I (0.0%) and Type II (20.2%), depending on the green coverage ratio. As for numerical characteristics, at the point of Ba in which the riffle ends, the water temperature fell by $0.2^{\circ}C$ and the flow increased from 0.7m/s to 0.9 m/s with the dissolved oxygen increasing from 0.5mg/L to 0.6mg/L. As for meteorological factors surrounding the subject stream, the temperature dropped from $1.1^{\circ}C$ to $1.4^{\circ}C$ on average and relative humidity increased from 6.6% to 8.7%. Furthermore, there was an irregular change in wind velocity. According to the result of the Wet Bulb Globe Temperature (WBGT), the change in the values of Type I and II inside and on the surface of the subject stream was negligible. The downstream temperature in Type I fell from $0.3^{\circ}C$ to $0.6^{\circ}C$ and by $0.8^{\circ}C$ in Type II. As for vertical cooling effect, the change of water level was 120cm in Type I and 140cm in Type II. As for horizontal cooling effects, the value of Type I was increased from the point of Ba where the riffle ends and the value of Type II was on a steady decline.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.517-529
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• 2020

Various facilities in the river working in a complex interdependence network result in both desired and adverse effects. Among these, the weir crossing the river continuously acts in various ways, such as securing river maintenance flow and water level during dry-period, and rising flood level during rainy period. Until now, weir planning was only limited to flood mitigation management. Recently, the demand for securing river environment functions is increasing. Therefore, the necessity for an environmental flow has emerged. Nevertheless, there is no analysis and evaluation of the ecological functional aspects applying the environmental flow when planning facilities. Therefore, this study aimed to develop and systematize an assessment method that considers not only flood control but also river environment. Environmental flow was applied to the weir named Dondaet-bo and hydraulic analysis was conducted for each retention, demolition, and re-installation case. Also, this research was conducted to minimize the impact on the surrounding river facilities and flood assessments from previous perspectives were performed. The study result demonstrated a plan to reinstall the weir as a natural riffle. Through this study, it is expected that the flood control and environmental functions of rivers can be secured in combination.

• Journal of the Korean housing association
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• v.25 no.6
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• pp.67-74
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• 2014

Dongseong-ro public design was reformed for a short time to be short of connection and riffle effect of another project and to have limitation on long term and integrated development, so that systematic plan from beginning of the project was needed to produce synergy effects. The purpose of the study was to investigate reformation of Dongseong-ro public design and to check on existing development project again and to take actions against future projects in advance and to reexamine and make long term plan from point of view of development of downtown. This study investigated reformation of Dongseong-ro public design of Junggucheong office of Daegu that was done from May 2007 to December 2010. The study consisted of purpose of the project, scope, time, the committee of promotion, questionnaire survey, residents' participation and follow up to suggest reformation based on questionnaire survey. This study had limitation of investigation into internal materials of 'Dongseong-ro public design reformation's master planning service' of Junggucheong office of Daegu. Further studies were needed to investigate empirically.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.623-631
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• 2006

A new model, the periodic transient storage zone model, is developed to describe solute transport mixing in natural streams and rivers with various bottom boundaries. To assess the effects of storage zones structure on transient storage exchange, we analyze data from salt and dye injection experiments in a recirculating laboratory flume with four spatially periodic pool-riffle sequences characteristic of natural river systems under low flow conditions. Dye injections show that solute transport mixing controlled by surface shapes of both the bed and the side in channels. As no existing transient storage model could represent these effects, we developed a new axially periodic transient storage zone model that better represent the effects of channel characteristics in natural river systems. The new model is also fitted to data from salt tracer injection experiments in four reaches of the upper Sabin River, Texas, USA. The proposed model is in good agreement with the field experimental data.