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        검색결과 24

        7.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Reproductive potential decreases with age. A decrease in male fertility is due to a combination of morphological and molecular alterations in the testes. Transient receptor potential vanilloid receptor-1 (TRPV1) is associated with aging and lifespan, and its activation causes apoptotic cell death in various cell types. However, the effect of TRPV1 on testicular apoptosis in aged mice has not yet been reported. TRPV1 knockout (KO) mice had a longer lifespan than that of wild-type (WT) mice. Lifespan was increased by 11.8% in male TRPV1 KO mice compared to that in WT mice. TRPV1 KO males lived approximately 100 days longer than WT males on average, and the maximum lifespan was markedly extended in TRPV1 KO mice compared with that in WT mice. The TRPV1 expression levels were highly increased in the testes of older mice. TRPV1 was expressed in the entire testes region of the old mice. In addition, old TRPV1 KO mice had lower testicular apoptosis than that of WT mice. Our results show that TRPV1 induces testicular apoptosis and suggest that TRPV1 may be associated with testicular aging.
        4,000원
        12.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 기존에 제안되었던 공정 중심 모델링 방법을 개선하여 조선소의 다양한 생산 정보와 제약조건을 효과적으 로 표현할 수 있도록 개선된 공정 중심 시뮬레이션 모델링 방법을 제안하였다. 그리고 이를 이용하여 시뮬레이션 모델을 구축할 수 있도록 다이어그램 구성 요소와 모델링 방법을 상세히 기술하였다. 이 모델링 방법에서는 복수의 제품과 설비가 공정에 투입되었을 때 우선순위를 지정할 수 있으며, 계층 구조를 가진 시뮬레이션 모델을 표현할 수 있도록 레이어 개념이 적용되어 있다. 그리고 조선 소 생산 계획 정보를 바탕으로 절단 공정부터 대조립 블록 조립 공정까지를 본 논문에서 제안하는 방법으로 모델링하다. 이를 통하여 본 논문에서 제안하는 방법이 단일 설비가 여러 용도로 사용되는 경우에 기존의 모델링 방법에 비하여 유리한 것을 확인하였다. 결과 적으로, 개선된 공정 중심 시뮬레이션 모델링 방법은 기존의 공정 중심 시뮬레이션 모델링 방법에서 표현하기 힘들었던 제약 조건과 흐름을 효과적으로 표현할 수 있으며, 계층 구조를 가진 조선소 생산 계획 검증 시뮬레이션 모델을 체계적으로 구축하는데 활용할 수 있다.
        4,200원
        17.
        2014.06 구독 인증기관 무료, 개인회원 유료
        시스템다이내믹스는 사회과학, 자연과학을 통틀어 다양한 현상을 체계화 시키고 동태적인 인과관계의 과학성을 분석하는데 있어 유용한 분석 방법론이다. 단기적 혹은 장기적인 사회성장에 관한 전략을 제시하거나 사고를 미연에 방지하기 위해 사례를 모아 원인을 분석하고 종합적인 고려를 통해 사고가 재 발생되지 않게 하는 정책을 제시할 수 있게 한다.
        3,000원
        19.
        2017.06 서비스 종료(열람 제한)
        Despite the expectation that small green spaces provide high cooling effects, making air temperatures drop such effect in urban areas has been less explored in comparison to larger parks and urban forests. These knowledge gap has required advanced techniques to record spatial and temporal data and analysis small green spaces cooling effects. A temperature-sensing unit with ventilated double cylinder shelter (TVC) meets the needs and is known as an advanced device to record temperature data more accurately using a T-type thermocouple with a ventilator. This device also can be useful to develop guidance to describe thermal environment with a finer scale and an experimental research design for identifying air temperature data with spatial analysis using TVC. However, how we would conduct transect survey with this device and make a thermal map based on the collected data is not well known. The purpose of the study was to find out the usage of TVCs in collecting air temperature data and was to produce a thermal map of the study site and analyze temperature mitigation effect of each green space. The processes to create a thermal map required complicating, endeavoring and time-consuming works as well as skills to use computer programs for space drawing and spatial analysis. The overview of all the processed to get a thermal map should be helpful for researchers and students. Collected air temperature data and recorded time of them were downloaded, converted to Excel file (XLS) and ready to be analyzed through ArcGIS 9. In the mean time, recorded transect routes were drawn on the site map as polylines and made into spatial points through AutoCAD 2007. The routes consisted of five routes classified into the lawn, the rain garden, the residence, the prairie, and the forest. Separately, each route was drawn because it should reflect its spatial and temporal specification as for when the measurement was conducted. The spatial points of each route created by AutoCAD were converted to shape files (*.shp) and added fields of air temperature and time data in their attribute tables through ArcGIS. This work was done in each measurement hour and day. To create a thermal map, were shape files of each measurement time and the boundary of the site required. IDW (Inverse Distance Weighted) in ArcGIS was analyzed for each measurement hour (10h, 13h, 16h and 19h (20h)). In each analysis, the spatial points of measured air temperature were calculated to get an isotherm distribution for the measurement hour which we call a thermal map. The thermal maps show the air temperature distribution at 10h, 13h, 16h, and 20h. They also can show how land covers have an impact on the change of air temperature on their point and the surrounding areas. The air temperature of the prairie raises up in the morning (21℃) and continues to be cool during the day and after sunset. Meanwhile, the lawn starts at lower air temperature and goes to hotter. The residence is kept lower in its air temperature by big trees. The rain garden and the forest seem to have more time to discuss on why they are not sure their cooling effects.
        20.
        2017.06 서비스 종료(열람 제한)
        Research to reduce urban temperatures and mitigate the Urban Heat Island (UHI) effect has focused primarily on the role of large urban green spaces as cool islands (Oke, 2004;Park et al., 2017). However, the role of small green spaces (SGs) such as street trees and pocket parks has not been fully investigated. The purpose of this research is to assess the mitigating effect of SGs on micro-UHI through a comparative analysis of air temperatures of SGs and non-green spaces (NGs), that include building-shaded spaces (BS) and non-shaded, impervious, paved spaces (PS) completely exposed to sunlight. Six urban blocks were the study site and in a highly developed area, Jongnogu and Junggu, Seoul, 37°34′N 126°58′E, South Korea and also located in the same micro-climatic zone. They had SGs which were vegetation patches presented as distinct areas of tree cover. And they were mapped through aerial images analysis and field survey. The experiment was conducted across six urban blocks in a highly developed area in Seoul, South Korea during daytime in summer. Two researchers at each block simultaneously recorded air temperatures at 1.5 m above the ground level using mobile loggers at one-minute intervals for an hour. Measurements were repeated three times, and 1,296 temperature readings were collected in total and made 174 mean temperature data. ArcGIS was used to perform solar radiation analysis to highlight SGs, BSs, and PSs on a thermal map. The highest air temperatures and the lowest air temperatures of each block were extracted and classified. ANOVA and Kruskal-Wallis H test utilizing SPSS statistics were used to verify the significant differences in mean air temperatures between SGs (TSG), PSs (TPS), and BSs (TBS). As a result, ΔTPS-B (the thermal effect of PSs on a block‘s air temperature) ranged from –1.38 ℃ to 2.28 ℃ with fifty-six points, ΔTBS-B (the thermal effect of BSs on a block’s air temperature) ranged from –2.38 ℃ to 2.38 ℃ with fifty-eight points and ΔTSG-B (the thermal effect of SGs on a block’s air temperature) ranged from –1.98 ℃ to 1.62 ℃ with sixty points. 68% (N = 41) of SGs were a negative number of ΔTSG-B while 50% of BSs shows a negative number. The result means that SGs contribute to reducing microscopic UHI than BSs which have much more shade area than SGs have. The results showed that SGs contributed to significantly reducing TBi up to 2.9 ℃ while BS reduced TBi up to 2.7 ℃. The highest TBi was on a PS. The air temperature difference between SGs and NGs over all the blocks ranged from 0.9 ℃ to 2.9 ℃. The air temperature difference between PS and SG was significant and ranged from 0.2 ℃ to 2.0 ℃, while the difference between BS and SG was significant and ranged from 0.1 ℃ to 1.2 ℃.
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