• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.137-141
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• 2008

Biochip, which implements bioanalytical process on a tiny surface, is one of candidates for medical diagnosis, drug screening, and molecular sensing. In general, a type of biochip based on microfluidics is composed of microcomponents including microchannel, pump, and valve, which require complicated processes. In this study, gray-scale photolithography(GSPL) was applied to fabricate a biochip with multiple layers. A mould for casting PDMS(polydimethylsiloxane) channel, was fabricated using GSPL. A gray-photomask was prepared by printing gray patterns on a high-quality glossy paper followed by photoreducing by 10:1 onto the photo-film. The formation of multiple layers was studied according to the change of gray level of pattern and the developing time. A biochip composed of a weir(multiple layer structure) and a reaction chamber in a single microchannel was fabricated in a glass plate. Finally, we investigated the application of biochip to antigen-antibody reaction by packing the microbead coated with antibody.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.159-159
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• 2019

In this study, the simulation of sediment deposition at Sangju weir reservoir, South Korea, was carried out using artificial neural networks. The ANNs have typically been used in water resources engineering problems for their robustness and high degree of accuracy. Three basic variables namely turbid water inflow, outflow, and water stage have been used as input variables. It was found that ANNs were able to establish valid relationship between input variables and target variable of sedimentation. The R value was 0.9806, 0.9091, and 0.8758 for training, validation, and testing phase respectively. Comparative analysis was also performed to find optimum structure of ANN for sediment deposition prediction. 3-14-1 network architecture using BR algorithm outperformed all other combinations. It was concluded that ANN possess mapping capabilities for complex, non-linear phenomenon of reservoir sedimentation.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.138-138
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• 2022

Understanding a stream's or river's discharge is essential for a variety of hydrological and geomorphological applications at various sizes. However, depending on the stream environment and flow conditions, it is crucial to use the appropriate techniques and instruments. This will ensure that discharge estimations are as reliable as possible. This study presents developed smart system for continuous measurement of open channel discharge and evaluate streamflow measurement over various techniques. This includes developed smart flow meter as flow point measurements, smart water level sensor (installed on Hydraulic Structure ? Weir) and current meters. Advantages and disadvantages of each equipment are presented to ensure that the most appropriate method can be selected. we found that smart water level sensor is more prominent once used during flood event as compared to smart flow meter and current meters, while current meters seems to show better accuracy once applied for open channel.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.4
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• pp.2090-2123
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• 1970

This paper is a report on the research of experimental model test of Andong Fill Dam, which has been planned by the Government of Korea as a project, of its over-flowing capacity in spillway, creation of minus pressure and structure of anti-water impulse in over-flow weir. Andong Fill Dam is one of the project of master development plant for water resources, locating at Nakdong River side of Korea, and is aimed to have a multi-purpose dam for flood-control, irrigation, water power, urban and industrial water supply. This dam is planned to erect in fill-dam type due to the improper soil foundation and condition for concrete dam. The refore for the proper and advantageous points, this is designed as center core fill dam. By a model minimized of Andong Fill Dam, held an experimental model test on water quentity of reservir, discharges of overflow part, low pressure and anti-water impulse of overflow part, which was conducted an experiment by flowing aspects through each section of spillway to find the changes of water pressure and that of water level, and corrected the section of each part in order to conduct a check on the creation of minus pressure not to be over acted to the allowable bundary of the section structure; and for the prevention of concentated scouring at the down stream side of flow.

• Earthquakes and Structures
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• v.22 no.4
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• pp.387-399
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• 2022

To study the seismic damage of masonry structures and understand the characteristics of the multi-intensity region, according to the Dujiang weir urbanization of China Wenchuan earthquake, the deterioration of 3991 masonry structures was summarized and statistically analysed. First, the seismic damage of multistory masonry structures in this area was investigated. The primary seismic damage of components was as follows: Damage of walls, openings, joints of longitudinal and transverse walls, windows (lower) walls, and tie columns. Many masonry structures with seismic designs were basically intact. Second, according to the main factors of construction, seismic intensity code levels survey, and influence on the seismic capacity, a vulnerability matrix calculation model was proposed to establish a vulnerability prediction matrix, and a comparative analysis was made based on the empirical seismic damage investigation matrix. The vulnerability prediction matrix was established using the proposed vulnerability matrix calculation model. The fitting relationship between the vulnerability prediction matrix and the actual seismic damage investigation matrix was compared and analysed. The relationship curves of the mean damage index for macrointensity and ground motion parameters were drawn through calculation and analysis, respectively. The numerical analysis was performed based on actual ground motion observation records, and fitting models of PGA, PGV, and MSDI were proposed.

• Korean Journal of Environment and Ecology
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• v.27 no.4
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• pp.437-448
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• 2013

The ichthyofauna and fish community were studied in Daecheon Stream from April to October 2012. During the survey period a total of 42 species belonging to 13 families were collected. Dominant species by number was Zacco platypus(32.3%) and Tridentiger brevispinis(12.8%). In biomass, the dominant species was Z. platypus(27.7%) and Chelon haematocheilus(11.9%). Also, eight Korean endemic fish species and one endangered species (Rhodeus pseudosericeus) were collected. In addition, two exotic species(Carassius cuvieri and Micropterus salmoides) and migration fish species(Anguila japonica) were observed. Based on the length-weight relationship of Z. platypus, the b value was 3.21~3.29, and the condition factor(K) was 0.89 on average with stable condition. According to similarity analysis, fish communities in Daecheon Stream were divided into three groups; the upper reaches near a reservoir(St. 1), the middle reaches (St. 2 to 4) and the lower reaches near a weir(St. 5). Dominant species at each group were Zacco koreanus(St. 1), Z. platypus(St. 2 to 4) and T. brevispinis(St. 5). This result suggested that artificial structures such as dam and a weir have a marked effect on the distribution of fish communities in Daecheon Stream.

• Journal of Korea Water Resources Association
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• v.42 no.7
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• pp.559-569
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• 2009

Due to environmental, economical and the other limitations, it has been more difficult to construct new large hydraulic structure such as dam. For this reason, it has been tried to use small hydraulic structure such as washland as alternative of hydraulic facility. Because the flood control effect of small hydraulic structure are affected by runoff volume, hydrograph, storage capacity and weir crest elevation, and design frequency must be predetermined for the design of the hydraulic structure. Multiple washlands will be required to satisfy enough peak reduction effect so that considering washlands as a network, rather than individually, are critical to analysis of flood reduction effect. In this study, new index for determination of optimal location for washlands is presented and the existing model for this determination is modified by adopting the new index. Developed new model is applied to Ansung river basin for examination and the new model shows its' applicability as a decision making criteria for the determination of optimal location for washlands.

• Animal Bioscience
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• v.34 no.5
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• pp.789-800
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• 2021

Objective: Conservation and genetic improvement of cattle breeds require information about genetic diversity and population structure of the cattle. In this study, we investigated the genetic diversity and population structure of the three cattle breeds in the Korean peninsula. Methods: Jeju Black, Hanwoo, Holstein cattle in Korea, together with six foreign breeds were examined. Genetic diversity within the cattle breeds was analyzed with minor allele frequency (MAF), observed and expected heterozygosity (HO and HE), inbreeding coefficient (FIS) and past effective population size. Molecular variance and population structure between the nine breeds were analyzed using a model-based clustering method. Genetic distances between breeds were evaluated with Nei's genetic distance and Weir and Cockerham's FST. Results: Our results revealed that Jeju Black cattle had lowest level of heterozygosity (HE = 0.21) among the studied taurine breeds, and an average MAF of 0.16. The level of inbreeding was -0.076 for Jeju Black, while -0.018 to -0.118 for the other breeds. Principle component analysis and neighbor-joining tree showed a clear separation of Jeju Black cattle from other local (Hanwoo and Japanese cattle) and taurine/indicine cattle breeds in evolutionary process, and a distinct pattern of admixture of Jeju Black cattle having no clustering with other studied populations. The FST value between Jeju Black cattle and Hanwoo was 0.106, which was lowest across the pair of breeds ranging from 0.161 to 0.274, indicating some degree of genetic closeness of Jeju Black cattle with Hanwoo. The past effective population size of Jeju Black cattle was very small, i.e. 38 in 13 generation ago, whereas 209 for Hanwoo. Conclusion: This study indicates genetic uniqueness of Jeju Black cattle. However, a small effective population size of Jeju Black cattle indicates the requirement for an implementation of a sustainable breeding policy to increase the population for genetic improvement and future conservation.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.195-206
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• 2021

In 2020, South Korea initiated research and development of a longitudinal connectivity evaluation between upstream and downstream based on stream ecosystem health. This study analyzed the migration of upstream and downstream migratory fish species, fish distribution characteristics, trophic guilds, tolerance guilds, and species composition changes from 2015 to 2020 at Songrim weir in Yeongok stream, where the cross-structure of an ice harbor-type fishway for fish movement was recently improved. A total of 5,136 fish, including 36 species, were collected and three major migratory fishes were identified, namely, Tribolodon hakonensis, Plecoglossus altivelis altivelis, and Oncorhynchus keta. According to the comparative analysis before (Pre-I) and after (Post-I) improvement of the fishway, the relative abundance of primary freshwater fish increased in the upstream section, while the number of migratory fishes decreased. The fish species that used the fishway in the Songrim weir were Tribolodon hakonensis (58.4%) and Plecoglossus altivelis altivelis(11.8%). According to the Wilcoxon Signed-Rank Test migratory fish showed a statistically significant difference (p<0.05) in the upstream and downstream, showing a biological improvement effect of the crossstructure. On the other hand, the annual change of migratory fish based on the MannKendall trend test did not significantly increase or decrease (p>0.05). Therefore, in the fish passage improvement project, it is necessary not only for physical, hydrological, and structural tests, but also for pre- and post-biological tests on the use and improvement effect of fishway.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.124-143
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• 2010

Cofferdam is a temporary levee or dam structure built by using sheet pile or earth materials to prevent water infiltration during construction work of bridge, dam, harbour dock, or hydraulic structures in the river. In this regard, it is required to secure cutoff ability for dry work and workability for rapid installation and removal of the temporary dam or levee structures. In this paper, case studies for design and construction of cofferdam were performed, and water diversion method was briefed with some examples of cofferdam type as well. For the case study details of design and construction were reviewed based on cofferdams under construction related to 16 submerged weirs of "The 4-river restoration project" and dam type cofferdam respectively. From the review, it was known that the method for changing the water flow is selected based on the data from geological and geo-hydraulic site investigation in order to mitigate environmental effects by making sure if the design cross-sectional area of flow and maximum working days are sufficiently guaranteed. Finally, the primary findings and main conclusion derived are summarized that determination of applicable type of cofferdam should be checked by case study and meet design requirements such as water inflow control, constructability.