• 한국지역사회생활과학회지
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• 제28권3호
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• pp.391-401
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• 2017

This study was conducted to evaluate the relationships between exposure level to pyrethroid pesticide and wearing of protective equipment in 194 Chung-nam orchard male farmers. The urinary metabolites of pyrethroid pesticides, including Cis, Trans, DBCA, and 3-PBA, were analyzed by GC/MSD. As a result of this study, the detection rate and exposure level of 3-PBA was the highest among pyrethroid metabolites discovered by orchard farmers. As a result of analyzing the actual conditions of wearing protective equipment by the subjects of this study, the rate of agricultural farmers who wore four pieces of protective equipment compared to agricultural farmers wearing a single piece of protective clothing was as high as 35.1%. Pyrethroid exposure levels were low when farmers wore more personal protective equipment (PPE). In conclusion, training with regards to pesticide hazards and protective equipment for farmers who spray pesticides will help reduce pesticide exposure levels.

• International Journal of Aeronautical and Space Sciences
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• 제17권3호
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• pp.332-340
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• 2016

A design optimization is performed for the double-bolted joint in cylindrical composite structures by using a simplified analytical method. This method uses failure criteria for the major failure modes of the bolted composite joint. For the double-bolted joint with a zigzag arrangement, it is necessary to consider an interaction effect between the bolt arrays. This paper proposes another failure mode which is determined by angle and distance between two bolts in different arrays and define a failure criterion for the failure mode. The optimal design for the double-bolted joint is carried out by considering the interactive net-tension failure mode. The genetic algorithm (GA) is adopted to determine the optimized parameters; bolt spacing, edge distance, and stacking sequence of the composite laminate. A purpose of the design optimization is to maximize the burst pressure of the cylindrical structures by ensuring structural integrity. Also, a progressive failure analysis (PFA) is performed to verify the results of the optimal design for the double-bolted joint. In PFA, Hashin 3D failure criterion is used to determine the ply that would fail. A stiffness reduction model is then used to reduce the stiffness of the failed ply for the corresponding failure mode.

• 동굴
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• 제93호
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• pp.69-78
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• 2009

많은 학자들은 현대 사회의 관광 형태를 단순히 '보는 관광'을 지나 '체험관광'의 시대로 변화했다고 주장한다. 이와 같이 기존 관광상품에 체험적 요소를 가미하려는 시도가 동굴관광에도 도입되고 있다. 정선의 화암굴과 같이 하나의 주제에 맞춰 다양한 전시관을 준비함으로써 체험관광자를 유입할 수 있다. 따라서 본 연구는 동굴의 에듀테인먼트 관광자원으로서의 특성을 부각시키는 방안을 제시하는데 목적이 있다. 이를 위해 동굴의 특성과 관광자원으로서의 가치를 정립한 후 동굴의 역할과 에듀테인먼트 동굴의 사례를 살펴보고 이를 구체화할 수 있는 방안을 제시하였다.

• 말소리와 음성과학
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• 제5권1호
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• pp.91-98
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• 2013

This paper investigated Korean prosody as it relates to graded internal structure in an identification function. Within Korean prosody, variants regarded as dialectal variations can appear as different prosodic scales, which contain the range of within-category variations. The current experiment was intended to show how the prosodic scale corresponding to the range of within-category differences relates to f0 contours for speakers of two Korean dialects, North Kyungsang and South Cholla. In an identification task, participants responded by selecting an item from two answer choices. The probability of choosing the correct response from the two choices was computed by a logistic regression analysis using intercepts and slopes. That is, the correct response between two choices was used to show a linear line with an s-shape presentation. In this paper, to investigate the graded internal structure of labeling, 25%, 50%, and 75% of predicted probability were assessed. Listeners from North Kyungsang showed progressive variations, whereas listeners from South Cholla revealed random patterns in the internal structure of the identification function. In this paper, the results were plotted using scatterplot graphs, applying the range of within-category variation and predicted probability obtained from the logistic regression analyses. The scatterplot graphs showed the different degree of the responses for f0 scales (i.e., variations within categories). The results demonstrate that the gradient structures of native pitch accent users become more progressive in response to f0 scales.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.20-28
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• 2016

In this study, an efficient method of designing laminate composite radar absorbing structures (RAS) is proposed with consideration given to the structural shape so as to improve aircraft stealth performance. The calculation of the radar cross section (RCS) should be decreased to enhance the efficiency of the stochastic optimization when designing an RAS. In the proposed method, RAS are optimized to match up the input impedance of the minimal RCS, which is obtained by using physical optics and the transmission line theory. Single and double layer dielectric RAS for aircraft wings are employed as numerical examples and designed using the proposed method, RCS minimization and reflection coefficient minimization. The availability of the proposed method is assessed by comparing the similarity of the results and computation time with other design methods. According to the results, the proposed method produces the same results as the stochastic optimization, which adopts the RCS as the objective function, and can improve RAS design efficiency by reducing the number of RCS analyses.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.260-263
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• 2005

The effects of internal manifold designs the reactant feed-stream in Polymer Electrolyte Fuel Cells (PEFCs) is studied to figure out mass flow-distribution patterns over an entire fuel cell stack domain. Reactants flows are modeled either laminar or turbulent depending on regions and the open channels in the bipolar plates are simulated by porous media where permeability should be pre-determined for computational analysis. In this work, numerical models for reactant feed-stream in the PEFC manifolds are classified into two major flow patterns: Z-shape and U-shape. Several types of manifold geometries are analyzed to find the optimal manifold configurations. The effect of heat generation in PEFC on the flow distribution is also investigated applying a simplified heat transfer model in the stack level (i.e. multi-cell electrochemical power-generation unit). This modeling technique is well suited for many large scale problems and this scheme can be used not only to account for the manifold flow pattern but also to obtain information on the optimal design and operation of a PEMC system.

• 생약학회지
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• 제45권4호
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• pp.326-331
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• 2014

In this study, we investigated pharmacologic activity of rice bran ethyl acetate fraction (RBE), based on their osteoblast enhancing effects. It has been found that REB have a stimulatory effect on the commitment of bi-potential mesenchymal precursor C2C12 cells into osteoblasts in the presence of BMP-2. Furthermore, RBE enhanced the BMP-2-stimulated induction of ALP, an early phase biomarker of osteoblast differentiation. In addition, Western blot analysis showed RBE enhanced the BMP-2-stimulated phosphorylation of p38, but not those of ERK or JNK. These findings show RBE has the potential to enhance the BMP-2-mediated commitment of C2C12 cells into osteoblasts and their differentiation through p38 activation.

• 한국물환경학회지
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• 제28권4호
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• pp.538-550
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• 2012

This study suggests a general methodology which is designed for assessing RDOC behavior at the catchment scale by coupling properly a series of steam flow and water quality simulation models and actual monitoring data set. The modified TANK model in which a river routing function is incorporated to the conventional one is applied to simulate the long-term daily stream flow data, and the simulated stream flow data is combined with the 7-parameter log-linear model coupled to the minimum variance unbiased estimator to simulate the long-term daily water quality (BOD, COD and TOC) loads. Finally, the regression analysis between the usually monitored water quality data (BOD, COD and TOC) and RDOC is combined with the simulated water quality data to manifest the spatio-temporal variability of RDOC flux behavior at the Korean TMDL catchment scale.

• 신재생에너지
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• 제1권2호
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• pp.41-52
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• 2005

The effects of internal manifold designs on the reactants feed-stream in Polymer Electrolyte Fuel Cells [PEFCs] is studied to figure out flow and thermal distribution patterns over an entire fuel cell stack. Reactants flows are modeled either laminar of turbulent depending on regions and the open channels in the bipolar plates are simulated by porous media where permeability should be pre-deter-mined for computational analysis. In this work, numerical models for reactants feed-stream In the PEFC manifolds are classified Into two major flow patterns: Z-shape and U-shape. Several types of manifold geometries are analyzed to find the optimal manifold configurations. The effect of heat generation in PEFC on the flow distribution is also Investigated applying a simplified heat transfer model in the stack level (i.e. multi-cell electrochemical power-generation unit). This modeling technique Is well suited for many large scale problems and this scheme can be used not only to account for the manifold flow pattern but also to obtain Information on the optimal design and operation of PEFC systems.

• 한국콘텐츠학회논문지
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• 제13권6호
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• pp.67-76
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• 2013

본 연구의 목적은 내재적 동기 이론과 플로우 이론의 통합을 통해 비디오 게임 이용자들이 가진 동기와 행위 간의 관계를 설명하는 이론적 모델을 제시함에 있다. 이를 위해 본 연구는 기술과 도전의 최적균형, 플로우를 통한 즐거움, 내재적 동기, 그리고 비디오 게임 장르 이용행위라는 변수들을 제시하고 이들 간의 인과적 관계성들을 조사하였다. 경로분석을 통해 변수들 간의 관계성을 검증한 결과, 내재적 동기는 최적균형과 즐거움의 경험에 의해 직접적, 간접적 영향을 받는 것으로 나타났으며, 이 내재적 동기는 신체게임과 공상게임 장르의 이용행위를 유의미하게 예측하는 것으로 나타났다. 하지만 전통게임 장르의 경우 내재적 동기와 유의미한 관계성을 나타내지 못했다. 또한 본 연구는 남성과 여성 비디오 게임 이용자들 간에 내재적 동기의 강도는 다르나, 내재적 동기가 게임 장르 이용행위를 유도하는 근본적인 관계들은 남녀 간에 상이하지 않음을 발견하였다.