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        검색결과 31

        5.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study is to develop the innovative application methodology of Geofoam for sustainable design of eco-bridges under deep soil cover. Traditionally, the soft maerial zone has been located on the top or above the buried conduit to reduce the earth pressures, which is called imperfect trench installation (ITI). There, however have been no previous studies for the application of ITI on buried arch structures. This study investigated the structural effects of Geofoam surrouding buried arch bridges, which was named as embedded trench installation (ETI). Various shapes and locations of Geofoam have been investigated for both ETI and ITI. The findings from this study showed that ETI could effectively increase the stability and sustainability of deeply buried eco-bridges.
        4,000원
        6.
        2017.10 구독 인증기관·개인회원 무료
        This research focuses on a scheduling problem in the semiconductor probing facility. Probing facility is composed of identical parallel machines and the parallel machines form three workstations for the tests with different recipes. Each machine can be set to three different tests and sequence-dependent setup times are required between operations due to temperature and probe card loading/unloading. Precedence relationship exists between three tests of each wafer lot. The scheduling problem for the probing facility is a parallel machine scheduling problem with precedence relationship and sequence dependent setup time. We develop heuristic algorithm to minimize makespan for the scheduling problem and numerical experiments are conducted to evaluate the performance.
        7.
        2017.04 구독 인증기관·개인회원 무료
        Cylindrical steel shell sections have been applied in various engineering fields particularly in recent installations of wind turbine towers. Hence, many researchers are interested in studying cylindrical steel shell structures. However, studies on the effect of the presence or absence of openings are insufficient. Thus, the design criteria for the opening as well as the behavior of wind turbine tower are not clearly presented. Therefore, this study examines the ultimate strength and the behavior of wind tower in consideration of openings, presence of stiffeners, changes in opening width, and thickness variation of stiffeners. ABAQUS, a universal finite element analysis program, was used in to conduct this research. Finally, the results of this study can be a reference for the design and production of wind towers with openings.
        8.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        FEM 수치해석을 위한 사면체격자 생성을 위해서는 물체의 볼륨정보를 표현할 수 있는 Boundary Representation (B-Rep) 모델이 필요하다. 공학분야에서는 파라메트릭 솔리드 모델링(Parametric Solid Modeling) 방법을 사용하여 BRep 모델을 정의한다. 반면 지질모델링은 메쉬 기반의 불연속(discrete) 모델링 방법을 사용하는데 이를 지질솔리드모델 (Sealed Geological Model)이라 부르며 지층, 단층, 관입암, 모델 경계면과 같은 지질학적 인터페이스들을 이용해 지질 도메인을 정의한다. 공학분야의 파라메트릭 모델링과 불연속 모델링 방식의 자료구조의 차이로 인해 불연속 B-Rep 모 델은 공학분야에서 사용하는 다양한 오픈소스, 상용 메쉬제작 소프트웨어와 쉽게 호환되지 않는다. 이 논문에서는 공학 용 메쉬 제작 소프트웨어와의 호환성을 가지도록 지질솔리드모델을 대표적인 오픈소스인 Gmsh와 상용 FEM 해석 소 프트웨어인 COMSOL로 변환하는 프로그램을 제작하였다. 지질모델링 소프트웨어를 통해 제작한 복잡한 지질구조모델 을 사용자 편의성을 갖춘 다수의 상용 소프트웨어서 쉽게 활용할 수 있어 지열, 암석역학 등 다양한 지구과학 시뮬레 이션 연구에 도움이 될 것으로 생각된다.
        4,200원
        9.
        2016.04 구독 인증기관·개인회원 무료
        The initial production scale of wind tower is very few. But recently, the production scale of wind tower structure has increased gradually because it maximizes the efficiency in green energy. Many researchers are studying the wind tower, but there is no study about the difference of allowable buckling stress of the wind tower with and without opening. Guideline of codes and standards are very limited when designing a wind tower with an opening. It is also rarely that a study considers the design of the wind tower to be a tubular shell with or without an opening. ABAQUS, a general purpose finite element program, which provides safety evaluation and economical standards for the design and behavior of the wind tower considering the effect of opening was used in the study. Finally, results from this study can serve as reference for structural engineers, manufacturers and further studies of wind turbine when designing a tubular shell wind tower with an opening.
        11.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        효과적인 광물자원 탐사 기술을 개발하기 위하여 광물자원의 포텐셜 지도 구축 연구를 수행하였다. 대상 지역은 광상 성인모델이 알려진 가곡광산으로 선정하였다. 성인모델을 바탕으로 관계화성암, 단층, 탄산염암 등의 지질학적 요인들을 평가 인덱스로 선정하였다. 각 요인들과 광체간의 공간적 상관관계를 분석하여 각 지질 구조 들로부터의 거리에 따른 가중치를 해석, 가곡광산에 대한 포텐셜 지도를 구축하였다. 해석된 포텐셜 지도는 현재 알려진 광체의 위치에서 높은 포텐셜 값을 갖으며, 높은 포텐셜 영역의 패턴 역시 광체 패턴과 유사하게 나타나고 있다. 이 결과는 추후 수행될 자원 탐사 시 현재 알려진 광체와 유사한 지질환경을 갖는 영역을 효과적으로 제시할 수 있기 때문에 그 효용성이 높다 할 수 있다.
        4,000원
        12.
        2013.12 구독 인증기관 무료, 개인회원 유료
        This study aims to comparatively analyze lower extremity joint moment during the take-off phase in high jump and thus to provide the basic data for enhancement of highschool students' high jump skills. 2 highschool students - one males and one females - were chosen for the experiment in which the 3D image analyzer and ground reaction force measuring unit were adopted. The results are as follows: Similar to the changing patterns from lower extremity joint moment but, moment values it turned out that male were better than female. The flexion and extension moment of lower extremity were most significant, abduction and adduction, medial rotation and lateral rotation were relatively small. The moment value in sagittal plane, frontal plane, transverse plane were appeared larger in the order of hip joint-knee joint-ankle joint. The muscle activity of knee joint and hip joint were acts in conjunction with sequential knee joint-hip joint.
        4,000원
        13.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This research is to evaluate the effects of zig-zag marking. METHODS : Based on the literature review, This research adopt Comparison Group method which was developed by Hauer. RESULTS : The findings are as follows. Effectiveness of treatment at all site 1.06, intersection 0.92, median bus lane 1.93, school zone 0.50, below 6-lane 0.48, above 6-lane 1.19, cat vs person 0.57, car vs car 1.36, car only 1.29. CONCLUSIONS : Though the analysis, it was founded that zig-zag marking on the small scale road(below 6-lane) and school zone contribute to reduce traffic accidents(effectiveness of the treatment : 0.50, 0.48). But the accidents at large scale road and median bus lane where installed zig-zag marking demonstrated negative result.(effectiveness of the treatment indicates exceed 1.0).
        4,000원
        14.
        2012.06 구독 인증기관 무료, 개인회원 유료
        Population densities of aerobic heterotrophic bacteria by plate counting method were in the range of 3.5 ± 0.2 × 106~1.8 ± 0.7 × 107 cfu g−1 dry wt. from the grasses of Gunsan Country Club which sampled from August to October, 2011. We selected the celluloytic bacteria from aerobic heterotrophic bacteria and identified 6 strains among ninety-six isolates by using 16S rDNA analysis. As a result, four isolates belonged to Firmicute group, two isolates belonged to Gamma-proteobacteria group and Actinobacteria group, respectively. We also analysed the cabon sources utilization patterns of six isolates. D-cellobiose, D-Fructose, D-Galactose, D-Mannose, DMelibiose, D-Psicose, Gentiobiose, Lactulose, L-Arabinose, L-Fucose, Turanose, α-D-Glucose, and α-D-lactose among 95 carbon sources are utilized by all six isolates.
        4,000원
        15.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korea had experienced second epidemic highly pathogenic avian influenza (HPAI), and there were the seven affected farms, including two breeder duck farms, from 22nd November 2006 to 6th March 2007. Here, we reported the clinico-pathological characteristics of domestic breeder ducks farms naturally infected with HPAI virus (H5N1). Clinically, the most ducks showed various signs from depression, decreased egg production and feed consumption to even, death. The most commonly gross changes were hepatomegaly, splenomegaly, petechial and ecchymotic hemorrhage on the liver surface, a white stripe on the cardiac muscle, and severely hemorrhagic and deformed eggs. The most significant histopathological changes were necrosis of various cells such as neuron, lymphocytes, cardiac myocytes, hepatocytes, blood vessels and pancreatic acinar epithelium. The viral antigen was mainly detected in the endothelium of blood vessels of various organs and tissues, peripheral nerves and neuronal cells. Based on the above results, we identified that HPAI H5N1 induced systemic infection in the adult breeder ducks.
        4,000원
        16.
        2009.12 구독 인증기관 무료, 개인회원 유료
        To get more comprehensive understandings about the microbial diversity near the seawater of Ulleung Island, East sea of Korea, the bacterial identification base on 16S rDNA and their carbon source utilization patterns were analysed through the six surface water samples collected at June 23 to 25, 2007. The results are as follows; the population densities of aerobic heterotrophic and oligotrophic bacteria were from 1.9±0.6×104~6.3±0.7 ×104 cfu ml−1 and from 1.7±0.4×103~2.5±0.4×103 cfu ml−1 during sampling periods, respectively. Among 121 isolated stains, the dominant taxa are Pseudoalteromonas spp. (30 colonies) and Alteromonas spp. (17 colonies). Thirty-senven species-level strains base on 16S rDNA sequencing data are identified, which comprised Gammaproteobacteria (14 strains), Alphaproteobacteria (6 strains), Flavobacteria (6 strains), Actinobacteridae (4 strains), Firmicutes (4 strains), Deinococci (2 strains), Betaproteobacteria (1 strains). The carbon utilization patterns by assay of Biolog-microplate, α-D-glucose are used by 88.9% of the 27 strains of Gram-negative bacteria and more than 80% of them also consumed L-arabinose, D-trehalose, L-alanine, and pyruvic acid methyl ester. On the other hand, all the 10 strains of Gram-positive bacteria used α-D-glucose, and more than 80% of them also exploited maltose, palatinose, D-trehalose, turanose, D-xylose, and pyruvic acid.
        4,000원
        17.
        2008.06 구독 인증기관 무료, 개인회원 유료
        Samples were taken from the surface waters around Dokdo Island to measure the physico-chemical and microbiological water qualities from June 23 to 26, 2007. Water temperature and dissolved oxygen were in the range of 20.7~20.9oC and 7.01~7.74, respectively. Salinity and pH were in the range of 34.5~34.8‰ and 8.23~8.37, respectively. Population densities of aerobic oligotrophic bacteria and heterotrophic bacteria by plate counting method were in the range of 2.4±0.5×103~3.0±0.3×103 and 4.4±0.6×103~6.0±0.9×103 cfu ml−1, respectively. Among thirty-seven isolates isolated from surface waters around Dokdo island by using 16S rDNA analysis, dominant species were closely related to Actionobacteria (7 clones), α-proteobacteria group (6 clones), and γ-proteobacteria group (4 clones).
        4,000원
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