• Structural Engineering and Mechanics
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• 제52권4호
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• pp.663-686
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• 2014

This paper deals with free vibration analysis of bidirectional functionally graded annular plates resting on a two-parameter elastic foundation. The formulations are based on the three-dimensional elasticity theory. This study presents a novel 2-D six-parameter power-law distribution for ceramic volume fraction of 2-D functionally graded materials that gives designers a powerful tool for flexible designing of structures under multi-functional requirements. Various material profiles along the thickness and in the in-plane directions are illustrated by using the 2-D power-law distribution. The effective material properties at a point are determined in terms of the local volume fractions and the material properties by the Mori-Tanaka scheme. The 2-D differential quadrature method as an efficient and accurate numerical tool is used to discretize the governing equations and to implement the boundary conditions. The fast rate of convergence of the method is shown and the results are compared against existing results in literature. Some new results for natural frequencies of the plates are prepared, which include the effects of elastic coefficients of foundation, boundary conditions, material and geometrical parameters. The interesting results indicate that a graded ceramic volume fraction in two directions has a higher capability to reduce the natural frequency than conventional 1-D functionally graded materials.

• 생약학회지
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• 제50권1호
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• pp.59-64
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• 2019

Cudrania tricuspidata Bureau (Moraceae) has been used for physical weakness, impotence and insomnia in traditional Korean medicine. In this study, cudratricusxanthone A and cudraxanthone D were isolated from roots of C. tricuspidata and quantification were achieved by using high performance liquid chromatography (HPLC) method with diode array detector. The isolated compound was identified by NMR analysis and HPLC method was validated by linearity, precision and specificity test. The results showed that calibration curves of two compounds indicated great linearity with a correlation coefficient ($R^2$) of 0.9976 and 0.9995. The limits of detection (LOD) for cudratricusxanthone A and cudraxanthone D were 1.15, $0.11{\mu}g/ml$. Intra-day precision of cudratricusxanthone A and cudraxanthone D were 0.32~1.99%, 0.09~3.32% and inter-day precision were 0.59~2.40%, 0.28~1.55% RSD (%) values, respectively. The specificity was confirmed by chromatograph and quantitative contents of cudratricusxanthone A and cudraxanthone D were $0.46{\pm}0.02%$ and $1.53{\pm}0.06%$. Therefore, this study can be used as a basic research data for the quantitative analysis of derived compounds from roots of C. tricuspidata.

• Journal of Multimedia Information System
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• 제9권2호
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• pp.127-136
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• 2022

In MMORPGs, there are many problems with the Grinding player experience. This research divides the Grinding player experience into four dimensions: Grinding in-Autonomy, Competence, Relatedness and Positive affect through theoretical investigation of game experience. Through the study of Litman (2008), Curiosity is divided into two dimensions, I-Type Curiosity and D-Type Curiosity, and the relationship between Curiosity and Grinding player experience is studied. By distributing questionnaires, collecting data, and using SPSS software to conduct reliability analysis, validity analysis, correlation analysis and multiple regression analysis on the data, it is verified that in MMORPG, I-Type Curiosity can positively affect Grinding in-Autonomy, Competence, Relatedness and Positive affect. D-Type Curiosity can positively affect Grinding in-Autonomy, Competence and Positive affect, but D-Type Curiosity has no statistical relationship with Grinding in-Relatedness. And through the standardized coefficient (Beta) value, between the Curiosity factors, I-Type Curiosity has a greater impact on Grinding in-Autonomy and Positive affect, and D-Type Curiosity has a greater impact on Grinding in-Competence. Finally, from the perspective of I-Type Curiosity and D-Type Curiosity, combined with the drawbacks of the MMORPG Gringding mechanism, some concrete and feasible suggestions and optimization schemes are put forward to improve the Grinding player experience. This research result can provide some feasible suggestions for MMORPG developers and designers, optimize the MMORPG Grinding mechanism from the perspective of I-Type Curiosity and D-Type Curiosity, and improve the Grinding player experience. It can provide appropriate assistance for the improved development of MMORPG games.

• KSBB Journal
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• 제16권5호
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• pp.435-441
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• 2001

In spite of the powerfulness for the simultaneous study of proteome expression and post-translational modification, 2-D PAGE has inevitable limitation on detect low aboundant proteins. Since many of the low abundant proteins are likely to have very important regulatiory functions in cells, separation and analysis of low copy number proteins is an important issue in proteome studies and challenge for 2-D techniques. Among various methods developed to detect low abundant proteins, electrophoretic protein prefractionation, chromatographic protein prefractionation, and subcellular fractionation are explained in this paper. Their practical strengths and weaknesses are also explained with current research trends.

• 한국전자거래학회지
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• 제26권2호
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• pp.45-59
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• 2021

4차 산업혁명의 핵심 동인으로서 Software(이하 SW)의 중요성이 더욱 커짐에 따라, 정부는 국가 경쟁력 강화를 위해 SW R&D 투자를 늘리고 SW 관련 정책을 지속적으로 수립하고 있다. 하지만 SW 연구개발에 대한 정부의 지속적인 투자에 비해, SW 연구개발 투자성과에 대한 체계적 분석은 부족한 실정이다. 본 연구에서는 Data Envelopment Analysis(DEA) 기법을 이용하여 SW 국가연구개발 사업의 분야별 효율성을 분석하였다. 2008년~2018년까지 정보통신산업진흥원(NIPA)에서 수행된 1,463개 과제정보를 토대로 효율성을 정태적/동태적 관점에서 측정하였다. 정태적 관점의 규모효율성 측정을 통해 비효율성 원인을 규모와 기술문제로 분석하였다. DEA/Window 모형을 이용한 동태적 효율성 분석 결과를 제시하고 효율성-안정성 매트릭스를 이용해 분야별 대응 모델을 제시하였다. 본 연구는 SW 국가연구 개발사업 전체를 대상으로 효율성 분석을 수행했다는 점에 의의가 있으며, 정태적/동태적 효율성 분석결과는 향후 SW 국가연구개발사업 기획 시 기초자료로 활용이 가능할 것으로 기대된다.

• 한국지반신소재학회논문집
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• 제4권4호
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• pp.3-11
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• 2005

본 연구에서는 지오텍스타일 백으로 보강된 철도노반 강화효과를 확인하기 위하여 실대형실험 및 2차원 평면 수치해석을 수행하였다. 선정된 지오텍스타일 백 축조노반위에 모사열차하중을 고려한 정적하중을 재하하여 무보강 노반과의 비교를 통해 정량적인 보강효과 및 성능을 평가하였으며, 2차원 평면 수치해석은 실대형실험과 동일 조건하에서 범용 FEM 프로그램인 Pentagon 2D를 이용하여 수치해석을 수행하여 비교 분석하였다. 각각의 실대형실험 및 2차원 수치해석결과 지오텍스타일 백의 재료특성, 인장특성, 지오텍스타일 백간의 마찰특성등에 의해 하중분산효과 및 침하저감효과를 확인하였으며, 2차원 수치해석결과가 실대형 실험결과 보다 전반적으로 작게 나타남을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.139-142
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• 2012

2D 콘텐츠 상품의 가치를 반영하기 어렵다. 3D 홀로그램 DID를 이용하면 상품의 매력도, 구매력, 인지도 등 DID영상 시스템이 필요하다. 본 연구에서는 3D 홀로그램, DID영상 시스템, 터치스크린, CMS를 설계하고 3D 홀로그램 콘텐츠 DID 영상시스템을 구현한다. 또한 2D 콘텐츠와 3D 콘텐츠와 3D 홀로그램 DID에 대해 매력도, 구매력, 인지도, 만족도 등을 비교분석한다.

• Nutrition Research and Practice
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• 제15권3호
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• pp.329-345
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• 2021

BACKGROUD/OBJECTIVES: Evidence has suggested an association between serum vitamin D and metabolic syndrome (MetS), but prospective studies are very limited. The objective was to assess the dose-response association between serum vitamin D concentration and MetS risk using a systematic review and meta-analysis of updated observational studies. MATERIALS/METHODS: Using MEDLINE, PubMed, and Embase, a systematic literature search was conducted through February 2020 and the references of relevant articles were reviewed. A random-effects model was used to estimate the summary odds ratio/relative risk and 95% confidence interval (CI). Heterogeneity among studies was evaluated with I² statistic. In total, 23 observational studies (19 cross-sectional studies, and four cohort studies) were included in the meta-analysis. RESULTS: The pooled estimates (95% CI) for MetS per 25-nmol/L increment in serum vitamin D concentration were 0.80 (95% CI, 0.76-0.84; I² = 53.5) in cross-sectional studies, and 0.85 (95% CI, 0.72-0.98; I² = 85.8) in cohort studies. Similar results were observed, irrespectively of age of study population, study location, MetS criteria, and adjustment factors. There was no publication bias for the dose-response meta-analysis of serum vitamin D concentrations and MetS. CONCLUSIONS: Dose-response meta-analysis demonstrated that a 25-nmol/L increment in the serum vitamin D concentration was associated with 20% and 15% lower risks of MetS in cross-sectional studies and cohort studies, respectively.

• 한국BIM학회 논문집
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• 제9권3호
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• pp.30-40
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• 2019

Extraction of fabrication documents is very important because it provides information related to tasks of fabrication and construction. Therefore, in the case of a prefabricated member such as a steel structure, it is necessary to improve the productivity of fabrication documents through 3D BIM. However, research and evidence data on direct comparison analysis of 3D BIM-based documents extraction versus 2D CAD-based documents extraction are hard to find. Thus, this study focuses on productivity analysis of 3D BIM based fabrication documents extraction. In this study, the productivity data of fabrication documents extraction for module construction of EPC project was analyzed. For the productivity analysis, a case study on the fabrication documents of Module A (1,965 sheets) and Module B (1,216 sheets) was conducted. Fabrication documents for each module include general arrangement drawing, assembly drawing, single part drawing and single plate drawing. Comparison of 2D CAD based fabrication documents extraction and 3D BIM based fabrication documents extraction, the productivity for the entire work was improved from 17 hours to 16 hours for Module A and 12 hours to 7 hours for Module B. Especially, the productivity of the assembly drawings, which occupies a large part of the fabrication documents, was improved by about 48.75% from the total time required from 281 hours to 144 hours.

• 한국소음진동공학회논문집
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• 제24권6호
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• pp.462-469
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• 2014

After drilling operations at the offshore plant, crude oil is producted under high pressure. After that time, oil recovery is reduced, because the pressure of the pipe inside is low during the secondary produce. At that time injection sea water at the pipe inside through water injection pump that the device increase to recovery. A variety of mathematical analysis during the detailed design analysis was not made through the dynamics characteristic at the domestic company. 2D model has reliability of analysis results for the uncomplicated model. Also element and the node the number of significantly less than in the 3D model. So, the temporal part is very effective. In addition, depending on the quality of mesh 3D is a real model and FEM model occurs error. So, user needs a lot of skill. In this paper, a 2D finite element analysis was performed through the dynamics analysis and the study model was validated.