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        검색결과 18,293

        5321.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구의 목적은 과학 글쓰기를 통해 고등학생의 지구 시스템에 대한 이해와 시스템 사고 과정을 분석하는 것 이다. 글쓰기 활동에 활용한 자료는 지구과학 I 교과 내용 중 지구환경 변화에 관련된 3가지 주제(지구 온난화, 화산 분출, 사막화)이며 이와 관련된 과제를 개발하였다. 개발한 자료는 고등학교 2학년 학생 8명을 대상으로 투입하였으며 작성한 과학 글쓰기 내용을 바탕으로 DAET-C 체크리스트와 지구 시스템에 관련된 개념을 구성요소로 하여 인과지도 를 작성한 후, 이를 근거로 하여 시스템 사고의 관점에서 분석하였다. 그 결과로 첫째, 학생들은 지구 시스템의 구성, 지구 시스템의 상호작용, 지구과학적 소양, 시스템 순으로 지구 시스템을 이해하는 것으로 조사되었다. 둘째, 학생들의 과학 글쓰기 내용을 바탕으로 각각의 주제별로 인과지도를 작성한 결과 피드백 순환 고리가 나타난 학생은 연구에 참 여한 8명 중 지구 온난화 관련 주제에서는 4명, 화산 분출 관련 주제에서는 1명, 사막화 관련 주제에서는 4명의 학생 이 지구 시스템에서 하위 요소 간의 상호작용을 고려하는 시스템 사고를 하고 있는 것으로 조사되었다. 결론적으로 연 구에 참여한 학생들은 지구환경 변화가 지구계 하위 요소 사이의 상호작용을 통해 복잡한 과정 속에서 복합적으로 이 루어지고 있다는 사고를 하고 있었으나, 지구 시스템의 순환에 대한 과정에서 시스템 사고는 미흡한 것으로 나타났다. 과학 글쓰기 활동을 활용하여 지구 시스템 교육과 시스템 사고를 향상 시킬 수 있는 다양한 연구가 필요할 것이다.
        4,600원
        5322.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed the correlation between Chl-a and water quality factors using characteristics of climate data, water quality factors, and various statistical analysis techniques during the summer season in the Nakdong River during the 2-year period. The purpose of this study is to provide the basic data for establishing water quality management policy in the Changnyeong-Haman weir section. From the end of July to the middle of August when algae mainly occur, both the years 2015 and 2016 are in the temperature range of 25 ~ 30 °C, and the total precipitation of 2015 is less than that of 2016 in this period. As a result of comparing the concentration of Chl-a, the average Chl-a concentration of 2015 was higher than that of 2016, which seems to be related to the total precipitation in the occurrence of algae. The results of the correlation analysis showed that the correlation with PO4-P was significant at most points. As a result of the factor analysis, the first principal factor group classified PO4-P, NH3-N, TP, pH, flow rate, TN and this section seems to be influenced by phosphorus and nitrogen and flow rate.
        4,000원
        5323.
        2017.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Ink-jet printing techniques with ceramic ink, which contains ceramic pigments as colorant, are in increasingly use in the ceramic industry. Generally, ceramic pigments that are produced by conventional method show diameters of several micrometers; these micrometer sized particles in the ink-jet printing process can cause undesirable behavior such as print head nozzle clogging. To prevent this problem, a particle size reduction process is required. In this study, CMYK (cyan, magenta, yellow, black) pigments were synthesized via solid state method. Each pigment particle was milled to submicron size by an attrition mill. The effects of micronizing on the morphology, mechanical property, crystal structure and color property of the CMYK ceramic pigments were investigated by field emission scanning electron microscopy (FE-SEM), particle size analysis (PSA), X-ray diffraction (XRD) and CIE L*a*b*.
        4,000원
        5324.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The goal of this study is to analyze the operational efficiencies of special roundabouts using simulated programs. METHODS: This study primarily focuses on comparing the delays and traffic flow disturbances occurring at special roundabouts. In this study, the operational efficiencies of 450 scenarios (5 roundabout types × traffic volumes × directional ratios × measures) are analyzed according to the corresponding delays and traffic flow disturbances using VISSIM and SSAM. RESULTS : The main results are as follows: 1) the Hamburger roundabouts are determined to yield the least common-type delays, 2) the amount of delays at Turbo and Flower roundabouts with respect to relatively increased right-turn-type delays, in addition to the amount of delays at the Left-turn slip-lane roundabout with respect to relatively increased left-turn-type delays, are found to be reduced as compared to the common-type delays. Lastly, common- and increased right-turn-type traffic flow disturbances at the Turbo roundabout and increased left-turntype traffic flow disturbances at the Left-turn slip-lane roundabout are determined to be the most infrequent. CONCLUSIONS: This study comparatively analyzes five roundabout types: standard, Flower, Turbo, Hamburger, and Left-turn slip-lane. The effectiveness of roundabouts can increase according to given traffic volume, directional ratio, and measure of effectiveness.
        4,000원
        5325.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to extract ginsenosides in by-products from honeyed red ginseng. Response surface methodology (RSM) was used to optimize the extraction conditions. Based on D-optimal design, independent variables were ethanol (extraction solvent) concentration (30-90%, v/v), extraction temperature (25-70oC), and extraction time (5-11 h). Extraction yield (Y1) and total ginsenosides (Y2) in the extract were analyzed as dependent variables. Results found that extraction yield increased with increasing extraction temperature and time, whereas it was decreased with increasing ethanol concentration. Similar trends were found for the content of ginsenosides in the extracts, except for ethanol concentration, which was increased with increasing ethanol concentration. Regression equations derived from RSM were suggested to coincide well with the results from the experiments. The optimal extraction conditions for extraction yield and total ginsenosides were an extraction temperature of 56.94oC, ethanol concentration of 57.90%, and extraction time of 11 h. Under these conditions, extraction yield and total ginsenoside contents were predicted to be 84.52% and 9.54 mg/g, respectively.
        4,000원
        5326.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The concern on the greenhouse gas emissions is increasing globally. Especially, the greenhouse gas emission from fisheries is an important issue due to Cancun Agreements Mexico in 1992 and the Kyoto protocol in 2005. Furthermore, the Korean government has a plan to reduce the GHG emissions as 5.2% compared to the BAU in fisheries until 2020. However, the investigation on the GHG emissions from Korean fisheries has not been executed much. Therefore, the quantitative analysis of GHG emissions from Korean fishery industry is needed as the first step to find a relevant way to reduce GHG emissions from fisheries. The purpose of this research is to investigate which degree of GHG emitted from the major coastal fisheries such as coastal gillnet fishery, coastal dual purpose fishery, coastal pots fishery and coastal small scale stow net fishery. Here, we calculated the GHG emission from the fisheries using the LCA (Life Cycle Assessment) method. The system boundary and input parameters for each process level are defined for LCA analysis. The fuel use coefficients of the fisheries are also calculated according to the fuel type. The GHG emissions from sea activities by the fisheries will be dealt with. Furthermore, the GHG emissions for the unit weight of fishes are also calculated with consideration to the different consuming areas. The results will be helpful to understand the circumstances of GHG emissions from Korean fisheries.
        4,300원
        5327.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the risk of overweight and obesity in adolescents consuming snacks frequently from 2007~2009, Korean National Health and Nutrition Examination Survey (KNHANES). The subjects (12~14 years: n=523; 15~18 years: n=614) were presented with food frequency questionnaires, and they were classified according to their gender and frequency of snack consumption. In the age group of 12~14 years, boys and girls (boys OR: 1.11, 95% CI: 0.52~2.39, girls OR: 12.45, 95% CI: 2.26~68.51) who consumed yogurt frequently had a higher risk of overweight and obesity at the highest quartile frequency compared with the lowest quartile after adjustments for multiple confounding factors, including age, physical activity, frequency of eating out and snack consumption, and energy intake. In the age group of 15~18 years, girls (OR: 1.01, 95% CI: 0.34~2.99) consuming fried foods had a higher risk of overweight and obesity at the highest quartile frequency compared with the lowest quartile after adjustments for multiple confounding factors, including age, physical activity, frequency of eating out and snack consumption, and energy intake. Thus, we conclude that frequent consumption of yogurt and fried foods increases the risk of overweight and obesity in adolescents. These findings suggest that the risk of overweight and obesity is associated with the frequency of snack consumption.
        4,000원
        5328.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        BIM 설계에서 라이브러리의 구축 및 활용은 매우 중요하다. 기존 컨텐츠의 재활용이 가능하므로, 설계를 보다 효과적이 고 효율적으로 진행할 수 있다. 건축분야와 달리 토목분야, 특히 철도시설분야에서는 라이브러리의 구축 및 표준화가 미진하 다. 따라서 본 연구에서는 철도시설분야에 3차원 객체 라이브러리를 구축하고 표준화하고자 한다. 철도시설물 분류체계 및 관련도면을 수집 및 분석한다. 분석된 표준도면의 항목과 분류체계 항목을 매칭하였다. 각 항목별로 라이브러리가 필요한지 여부와 그럴 경우 어떤 소프트웨어가 적절한지를 검토하였다. 사용가능한 소프트웨어는 주로 Civil 3D와 Revit 등으로 나타 났다. 향후 이를 바탕으로 철도인프라 3차원 라이브러리의 속성 항목 및 명세서를 설계하고 라이브러리를 구축할 예정이다
        4,000원
        5329.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the perception about the popularization of temple food, known as health food and adult disease prevention food as an object of total 248 residents in Youngnam region. From the result of this research above, it may be summed up as follows. This study has found out that the advantages of temple food showed the statistical significant difference according to the gender, age, and size of family (p<0.01). The reason 'because of health food' (66.7%) had such high percentage. The necessity of popularization of temple food had big difference according to the gender and age (p<0.01). In addition, this study has shown the statistical significant difference in the cooking form for popularization by age, and future improvement for popularization by age and size of family (p<0.001). And, this study has found out that the 'traditional way as it is' (57.3%) was high in the cooking form, and 'use of various materials' (27.4%) in the improvement. Furthermore, the necessity of using meat for temple food had significant difference according to the gender and age, and 'need' (33.9%) showed rather higher tendency. The necessity of using osinchae, five forbidden pungent roots like garlic, green onions, Korean leeks, wild chives, and asafetida had significant difference according to the gender, age and size of family (p<0.05, P<0.001). The 'need' (61.3%) was considerably high. Based on the above results, general customers thought that the need for popularization of temple food and use of osinchae was very positive.
        4,000원
        5330.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to investigate the fundamental behaviors such as stresses and deflections of the middle slab in a double-deck tunnel for the development of a middle slab design guide. METHODS : The middle slab has been divided into the following three different sections as according to its structural differences: the normal section, expansion joint section, and emergency passageway section. The normal section of middle slab represents the slab supported by brackets installed continuously along the longitudinal direction of tunnel lining. The expansion joint section refers to a discontinuity of middle slab due to the existence of a transverse expansion joint. The emergency passageway section has an empty rectangular space in the middle slab that acts as an exit in an emergency. The finite element analysis models of these three sections of middle slab have been developed to analyze their respective behaviors. RESULTS: The stresses and deflections of middle slab at the three different sections decrease as the slab thickness increases. The emergency passageway section yields the largest stresses and deflections, with the normal section yielding the smallest. CONCLUSIONS: The stress concentrations at the corners of the passageway rectangular space can be reduced by creating hunch areas at the corners. The stresses and deflections in the emergency passageway section can be significantly decreased by attaching beams under the middle slab in the passageway area.
        4,000원
        5331.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For economic evaluation of integrated operation to sewage facilities, benefit-cost analysis was performed to watershed sewage works project in 7 watershed areas, 156 facilities. In this study, the cost before and after integrated operation was compared and benefits are calculated from the reduction of operators, increasement treated pollution loads, reduction cost through operation convenience, reduction water consumption through effluent reuse, and improvement of life benefit. The result showed that cost was 8,500million won and benefit was 16,747million won, so benefit was 49% higher than cost. B/C analysis result showed that B/C ratio was 1.97 and it is similar to other researches. The benefits of integrated operation included convenience of data management, increase of emergency response, decrease of complains with sewage which was not reflected numerically, so the benefits of integrated operation were expected much greater than this result.
        4,000원
        5332.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of 27.12 MHz radio frequency (RF) heating on heat transfer phenomena during the thawing process of frozen food. To determine the velocity of the RF thawing machine, samples were frozen at -80oC and subjected to different power treatments. The phase change times (-5 to 0oC) of frozen radish were 30, 26, 13, and 8 min; those of pork sirloin were 38, 25, 11, and 5 min; those of rump were 23, 17, 11, and 6 min; those of chicken breast were 42, 29, 13, and 9 min; and those of tuna were 25, 23, 10, and 5 min at 50, 100, 200, and 400 W, respectively. The heating limit temperatures of the radish, pork sirloin, rump, chicken breast, and tuna samples were 19.5, 9.2, 21.8, 8.8, and 16.8oC at 50 W; 23.5, 15.5, 27.3, 12.3, and 19oC at 100 W; 42, 26.9, 45.7, 22.1, and 39.4oC at 200 W; and 48.5, 54.7, 63.6, 57.3, and 44.9oC at 400 W. These results suggest that high-power RF improves thawing velocity and heating limit temperatures, and that an improvement on the operation of the RF thawing machine, according to food temperatures, is needed.
        4,000원
        5333.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        연구에서는 고분자전해질 연료전지(PEMFC)의 전해질막의 성능향상을 위하여 sulfonated graphene oxide (sGO)와 Nafion을 이용하여 복합막을 개발하였다. sGO/Nafion 복합막 안의 sGO의 균일한 분산을 위해 각기 다른 용매를 사 용한 sGO 분산액과 Nafion 현탁액을 혼합하여 복합막들을 제조하였다. 제조된 복합막들의 물성 및 전기화학적 특성을 평가 하기 위해 SEM, FT-IR, 이온 전도도, 이온 교환 용량, 함수율, 열안정성 등을 수행하였다. 연구 결과 ODB와 DMAc 혼합 용 매로 sGO를 분산하여 고분자 용액 내에서의 분산도를 향상시켰으며, 이 결과 11 wt%의 낮은 함수율에도 불구하고, 0.06 S cm-1의 기존 연구와 유사한 이온 전도도를 나타내었다.
        4,000원
        5334.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This transport cask for radioactive materials will be used in the Gijang reactor. It will transport the Ir-192 10,000 Ci or I-131 80 Ci. In this case, the safety evaluation, such as protection of leakage of radioactive material, and radiation shield should be carried out before it is used in the research reactor. The safety regulation requires various tests, such as water spray, free drop, penetration, and water immersion. But this paper considers only the regulations related with thermal-stress and drop impact under the normal conditions because it will be used only in the research reactor building. In this paper, coupled numerical analysis was performed using finite element simulation to investigate the effect of position of tungsten and lead to enhance the safety of transport cask. As a result of simulation, it was verified that the Tungsten-Lead structure is the most durable among the cases considered in the study with a viewpoint of thermal-stress and drop impact.
        4,000원
        5335.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 산림소유자의 숲가꾸기 사업에 대한 인식 및 요구사항 등을 설문조사를 통해 분석하여 향 후 정책적 개선방안 수립의 기초자료를 제공하기 위해 수행되었다. 산림소유년수에서는 부재산주, 소재 산주 모두 10년 이상이 가장 높았고, 소유목적에서 부재산주는 묘지이용, 소재산주는 목재생산이 가장 높게 나타났다. 소유산림을 경영하지 않는 이유는 소득 미발생, 소득원에 대한 정보부족, 경영기술 부 족이 원인인 것으로 분석되었다. 향후 경영계획에 대해 부재산주는 목재생산과 산림휴양 및 체험, 소재 산주는 목재생산, 산림휴양 및 체험, 조경수재배의 비율이 높은 것으로 나타났다. 숲가꾸기 사업에 대 해 산림소유자는 전반적으로 만족하는 것으로 나타났다. 숲가꾸기 사업에 대해 불만족하는 요인으로 부 재산주는 소득 미발생과 담당자의 전문성 부족, 소재산주는 사전설명 불충분, 소득 미 발생, 담당자의 전문성 부족을 들었다. 숲가꾸기 사업에 동의하기 위해 부재산주는 정부지원금 확대, 소재산주는 산주 의 요구수용을 가장 중요한 조건으로 제시하였다. 본 연구결과는 앞으로 지속적인 숲가꾸기 사업을 통 해 품질향상을 위한 기초자료로 활용될 수 있을 것이다.
        4,300원
        5336.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze the current status relating to food packaging and design for status of small and medium food enterprises. A company survey was conducted from June to October, 2015 and targeted 1300 small and medium domestic food enterprises. Finally, a total of 1300 (recovery rate 100%) useable data were selected. Statistical analyses were performed on the data utilizing the SPSS PASW Statistics 18.0 for Windows, such as descriptive statistics and frequency analysis. According to the results, awareness and importance of food labeling were high, but performance of English inscription of product name was relatively low. The most important reason for food labeling was ‘providing correct information on food’ 910 (72.8%). Accordingly, a system which can provide the latest information by continuously monitoring mandatory disclosure requirements for types of foods in individual countries is needed.
        4,500원
        5337.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 벤처창업기업의 대표자 기술혁신역량과 경영진의 전문화, 기술사업 투 자계획의 타당성 등이 기업의 경영성과인 재무건전도와 나아가 부실화가능성에 미치는 영향에 대하여 구조방정식 모델(SEM)을 이용한 실증분석을 실시하였다. 본 연구는 2011년∼2012년 2 년 동안 1,419개 표본기업에 대한 기술보증기금 기술평가 전문가들의 현장평가 데이터와 기업 현황 조사정보 및 재무정보 등을 활용하였으며, 설립후 7년이내 기술력 기반의 벤처기업들 속성 상 ‘고위험⋅고수익’으로써 여타기업보다 부실화가능성이 높은 기업군인 점을 감안하여 이들 기 업을 연구대상으로 설정하였다. 분석 결과, 대표자의 풍부한 경험과 기술지식 등 기술혁신역량 과 경영진의 분야별 전문화를 바탕으로 한 체계적 조직운영, 그리고 적정규모의 기술사업 투자 ⋅재무관리 계획수립 및 합리적 추진 등을 통하여 기업의 성장성과 수익성 등 기업의 전반적인 재무건전도를 향상시키고, 나아가 단기적 부실화리스크도 감축시키는 것으로 확인되었다.
        5,600원
        5338.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study mechanically analyzed the performance of road substructures with focus on infiltration trenches of pavement substructures. METHODS: Water contents and response times for precipitation of pavement substructures were investigated via sensors buried near the infiltration trench to measure water contents. RESULTS : The results of the water contents of pavement systems constructed with an infiltration trench yield levels that were slightly increased by approximately 2% compared to those measured from general pavement systems. This water content difference of 2% resulted in a decrease in service life of less than two years. CONCLUSIONS: Service life reduction due to an infiltration trench is minimal, particularly when the trench is installed with proper caution.
        4,000원
        5339.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        선박의 대형화, 고속화 및 선종의 다양화는 운송수단 중 해양 운송수단의 비중을 크게 증가시켰다. 선박사고 유형 중 기관손상 다음으로 충돌이 사고발생 빈도가 높았으며, 인적 요인에 의한 사고비율이 높은 것으로 보고되고 있다. 선박 충돌사고는 한 가지 원인요소로 발생하는 경우보다 복합적인 원인요소로 발생하게 되며 여러 개의 원인요소를 재결서를 통하여 원인요소를 조사할 필요가 있다. 본 연구에서는 해양안전심판원에서 제공하는 재결서 중 선박 충돌사고에 대해서 인적 요인을 바탕으로 선박 충돌사고의 원인요소를 도출하였으며, 상관관계분석을 통하여 원인요소들을 규명하였다. 또한, 선박충돌을 인지한 시점에서부터 충돌이 일어난 시점까지 걸린 시간을 바탕으로 충돌을 피할 수 없는 충돌시점에서의 발생되는 주요 원인요소와 20분 내에 발생하는 선박 충돌사고의 원인요소를 분석하여 선박 충돌사고를 예방하고자 하였다. 상관분석은 상용소프트웨어인 Statistical Package for Social Sciences(SPSS Ver21.0)을 사용하였다. 시간 분석은 재결서를 바탕으로 상대방 선박을 인지한 시점에서부터 충돌이 일어난 시점까지 걸린 시간을 분석하였다. 선박 충돌사고의 원인요소는 2가지 이상에 의해 발생한 사고가 많았으며, 상대선박 감시소홀은 항해업무 외 다른 작업과 높은 상관관계가 있었다. 충돌을 피할 시간 여력이 없는 경우(0분)이 36.1 %이며, 경계 또는 상대 선박 감시소홀과 졸음항해 또는 음주가 원인요소이었다.
        4,000원
        5340.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        입자 복합재료는 입자의 형상, 크기 그리고 분포의 산포특성으로 인해 물성치의 편차가 존재하고, 입자 복합재료를 사용 한 시스템의 거동 또한 산포가 존재한다. 하지만 입자의 산포특성을 고려하기 어려우므로 균질화법을 사용하여 시스템의 거 동을 해석하거나 국부영역에서 미세구조를 적용하여 해석한다. 본 연구에서는 입자의 랜덤적 산포특성을 고려하기 위해 RMDFs(random morphology description functions)를 사용하여 랜덤 미세구조를 생성하였고, 단면 1차 모멘트를 사용하여 가우시안 함수의 수(N)와 입자의 산포특성의 관계를 분석하였다. 그리고 랜덤 미세구조 구조물의 거동을 분석하기 위하여 랜덤 미세구조를 전체에 반영한 외팔보에 multi-scale 해석을 수행하였다. 그 결과 입자의 산포특성과 외팔보의 처짐의 편차 는 N의 증가에 따라 감소하고 N=200에서 수렴하는 것을 확인하였다.
        4,000원