검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 116

        83.
        2017.09 서비스 종료(열람 제한)
        Recently, researches on FRP bars have been carried out as a solution to improve the durability of reinforcing steel bars. In the study, an experimental program was conducted to evaluate the development performance of GFRP bars for SFRC beams. Specimens were failed by splitting fracture. The development performance by the center lap joint was larger than the development of end of beam. As the lap length increased, the development performance was increased but not proportional.
        85.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        A statistical change-point analysis examined the existence of climate regime shift in the time series of the Asian dust frequency in Seoul during spring. As a result, the Asian dust frequency in Seoul during spring has sharply increased since 1993. To investigate the cause of the increasing Asian dust frequency in Seoul during spring, therefore the averages during the period of 1993 to 2011 and the differences in large-scale environment during the period of 1974 to 1992 were analyzed. According to the analysis results for 850 hPa, 500 hPa, and 200 hPa stream flows, northwesterly anomaly was formed from the Lake Baikal to the Korean Peninsula due to the intensification of anomalous anticyclonic circulation in Northern China. This northwesterly anomaly has become a major circulation that moves the sand particles from Northern China to Seoul.
        86.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        A new extraction method-heated ultrasonic extraction was qualitatively and quantitatively analyzed for the extraction of major ginsenosides from ginseng extract; this new high-performance liquid chromatography (HPLC) method was compared with the official extraction method of Korean industrial standards and standard for health functional food. Methods and Results : Ginsenoside compounds were analyzed for 35 minutes by the new HPLC analysis method using a Halo® RP-Amide column. The new HPLC analysis method was validated by the measurement of intra-day and inter-day precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ) of each ginsenoside. The correlation coefficients (r2) for the calibration curves of the ginsenoside compounds were over 0.9997 in terms of linearity. The heated ultrasonic extraction method using ultrasonication for 30 minutes at 50℃ yielded higher amount of ginsenosides than the extraction method of the Korean industrial standards owing to the enhancement of extraction efficiency. Conclusions : Compared to the other extraction methods, the heated ultrasonic extraction method yielded a higher amount of ginsenoside Rb1 than Rg1 index compounds for the quality evaluation of ginseng roots.
        87.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        This study analyzed the frequency of heatwave occurrences in Jeju Island in summer season (June to September) for the recent 46 years (1968-2013). The frequency showed an increasing trend up until now and we applied statistical change-point analysis in order to determine whether this increasing trend had a climate regime shift. As a result, it was discovered that frequency of heatwave occurrences has rapidly increased since 1990. Thus, to determine the causes of rapid increase in frequency of heatwave occurrences in Jeju Island since 1990, a difference in mean values of June to September between a period of 1990-2013 and a period of 1968-1989 was analyzed. The analysis result of differences between two periods about stream flows showed that large anomalous anticyclonic circulations were strengthened in the subtropical western Pacific and the center of the small anomalous anticyclone, which was branched westwardly out of the anticyclonic circulations was located within the southern part of the Korean Peninsula. This strengthening of the anomalous anticyclone in the Korean Peninsula was also shown at the middle and upper troposphere. The anomalous anticyclonic circulations, which were expanded to the Korean Peninsula from the subtropical western Pacific in recent years was due to strengthening of the western North Pacific subtropical high (WNPSH) in the Korean Peninsula. Hot and humid air can be introduced into the Korean Peninsula due to the strengthening WNPSH in the Korean Peninsula. Furthermore, a difference in daily maximum temperature at 2m height as well as sensible heat net flux between two periods were analyzed in order to determine the degree of the heat at the ground. There was positive anomalies found along the coast in East Asia and the center of the positive anomalies was linked to the Korean Peninsula via the northern part of China. Thus, the Korean Peninsula including Jeju area had more heat than usual in recent years.
        88.
        2015.11 KCI 등재 서비스 종료(열람 제한)
        This study analyzes the characteristics of Western North Pacific (WNP) tropical cyclone (TC) activity and large-scale environments according to the Western Pacific (WP) teleconnection pattern in summer. In the positive WP phase, an anomalous cyclone and an anomalous anticyclone develop in the low and middle latitudes of the East Asia, respectively. As a result, southeasterlies are reinforced in the northeast area of the East Asia including Korea and Japan which facilitates the movement of TC to this area, whereas northwesterlies are reinforced in the southwest area of the East Asia including South China and Indochina Peninsula which blocks the movement of TC to this area. Due to the spatial distribution of this reinforced pressure system, TCs develop, move, and turn more to the northeast of WNP than those in the negative WP phase. Consequently, the characteristics of this TC activity in the positive WP phase are associated with the location of upper tropospheric jet further to the northeast. Meanwhile, TCs in the negative WP phase mainly move to the west from Philippines toward south China and Indochina Peninsula. Furthermore, due to the terrain effect caused by the high passage frequency of TCs in the mainland China, the intensity of TCs are weaker than those in the positive WP phase.
        89.
        2015.07 KCI 등재 서비스 종료(열람 제한)
        This study analyzes the correlation between Western Pacific (WP) teleconnection pattern index (WPI) in April during 1954-2008 and rainfall amounts in the same month. Based on the results, it is identified that there have been strong positive correlations between central China, Korea and the southwestern part of Japan in the East Asian region. Through differences between 10 positive WP years and 10 negative WP years selected from the April WPI excluding ENSO years, it is found that rainfall amounts increase in April of positive WP years due to the following characteristics. Increases in rainfall amounts are evident in the East Asian middle latitudinal region where the positive correlation between the two variables is the highest and this is because anomalous southwesterlies are strengthened in the East Asian middle latitudinal region due to the spatial pattern of a south-low-north-high anomalous pressure system centered on this region that is made by anomalous anticyclones centered on the southeastern side of the region and other anomalous anticyclones centered on the northeastern side of the region. In addition, anomalous westerlies (jet) are strengthen in the upper troposphere of the East Asian middle latitudinal region and as a result, anomalous upward flows are strengthened in this region and thus anomalous warm air temperatures are formed in the entire level of the troposphere in the region. In addition to atmospheric environments, anomalous warm sea surface temperatures are formed in the seas in the East Asian middle latitudinal region to help the rainfall amount increases in the East Asian middle latitudinal region.
        90.
        2015.07 KCI 등재 서비스 종료(열람 제한)
        This study analyzed the climate regime shift using statistical change-point analysis on the time-series tropical cyclone (TC) frequency that affected Japan in July to September. The result showed that there was a significant change in 1995 and since then, it showed a trend of rapidly decreasing frequency. To determine the reason for this, differences between 1995 to 2012 (9512) period and 1978 to 1994 (7894) period were analayzed. First, regarding TC genesis, TCs during the 9512 period showed a characteristic of genesis from the southeast quadrant of the tropical and subtropical western North Pacific and TCs during the 7894 period showed their genesis from the northwest quadrant. Regarding a TC track, TCs in the 7894 period had a strong trend of moving from the far east sea of the Philippines via the East China Sea to the mid-latitude region in East Asia while TCs in the 9512 period showed a trend of moving from the Philippines toward the southern part of China westward. Thus, TC intensity in the 7894 period, which can absorb sufficient energy from the sea as they moved a long distance over the sea, was stronger than that of 9512. Large-scale environments were analyzed to determine the cause of such difference in TC activity occurred between two periods. During the 9512 period, anomalous cold and dry anticyclones were developed strongly in the East Asia continent. As a result, Korea and Japan were affected by the anomalous northerlies thereby preventing TCs in this period from moving toward the mid-latitude region in East Asia. Instead, anomalous easterlies (anomalous trade wind) were developed in the tropical western Pacific so that a high passage frequency from the Philippine to the south China region along the anomalous steering flows was revealed. The characteristics of the anomalous cold and dry anticyclone developed in the East Asia continent were also confirmed by the analysis of air temperature, relative humidity and sensible heat net flux showing that most regions in East Asia had negative values.
        91.
        2015.06 KCI 등재 서비스 종료(열람 제한)
        This study analyzed a correlation between South China Sea summer (June to September) monsoon (SCSSM) and the ENSO for the last 32 years (1979 to 2010). There was a correlation that the higher (lower) the SST in the Niño-3.4 region was, the weaker (stronger) the SCSSM intensity was. To identify the reason for this correlation, a difference of means between 8 El Niño years and 8 La Niña years (June to September). The analysis on the difference between two groups with respect to the 850 hPa stream flows showed that there were anomalous huge cyclones in the subtropical Pacific in the both hemispheres so that cold and dry anomalous northerlies were strengthened in the South China Sea relatively while anomalous westerlies were strengthened from the Maritime Continent to the off the coast of Chile. The analysis on the difference between two groups with respect to the 200 hPa stream flows showed that the opposite anomalous pressure system pattern to that in the 850 hPa stream flows were shown. In the subtropical Pacific of the both hemispheres, anomalous anticyclones existed so that anomalous easterlies were strengthened from the Maritime Continent to the equatorial central Pacific. Considering the anomalous atmospheric circulations in the upper and lower layers of the troposphere, upward airflows from the equatorial central and eastern Pacific were downward in the South China Sea and the Maritime Continent, which was a structure of anomalous atmospheric circulations. This means that the Walker Circulation was weakened and it was a typical structure of atmospheric circulations revealed in El Niño years.
        93.
        2015.04 서비스 종료(열람 제한)
        This research investigated the effect of fiber orientation on the tensile strength of PVA, PE and Basalt fiber. Test results showed that the fiber strength reduction coefficients of PVA, PE, and Basalt fibers were 0.171, 0.485, and 1.54, respectively.
        94.
        2015.04 서비스 종료(열람 제한)
        This research is in developing a seismic isolation system for protecting a structure such as small non-structural assets at this point of time where seismological observation is on the rise in internal and external. this seismic isolation system was produced by using the damper with restoring force and damping force, and the LM guide which enable linear behavior, and progressed performance test.
        95.
        2015.02 서비스 종료(열람 제한)
        전기화재의 주요 요소는 전기아크와 스파크로 인한 것으로, 전기화재를 효과적으로 예방하려면 아크차단기(AFCI)의 설치를 법령으로 의무화 되어야 한다. 그러나 우리나라에서는 경제적인 이유와 합리적인 대안의 부재로 인해 현실적으로 어려운 실정으로 추진체계 또한 오랜 시간이 소요될 것으로 예상된다. 이에 대한 합리적인 대안으로 본 연구에서는 응답성과 신뢰성이 우수한 디지털 소자와 반도체 스위칭 소자 등을 이용하여, 선로전압을 상시 감지하고 일정 시간 내 아크나 스파크로 판단되는 이상 파형이 감지되면 화재의 징후로 인식하여 신속하게 전로를 차단하는 직력 아크사고의 감지시스템을 개발하고자 한다. 제안한 전기화재 보호장치는 제어방식이 간단하고 경량, 소형으로 제작이 가능하게 때문에 어디에서나 쉽게 적용이 가능한 장점이 주어진다.
        96.
        2014.10 서비스 종료(열람 제한)
        In this study, the applicability evaluation of basalt fiber surface treatment with fluorination. Test results showed that significantly reduce the tensile strength through the basalt fiber surface treatment with fluorination.
        97.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        Purpose: of the study was to investigate whether aerobic exercise has a positive effect on executive function and EEG with Attention Deficit Hyperactivity Disorder(ADHD) children and provides a basic data for relieving symptom and treatment to ADHD children. Methods: Research participants were totally 44 children. The group distribution was combination of exercise and methylphenidate group(n=16), methylphenidate group(n=14), and the control group(n=14). Research subjects pre․post measurement was made equally on executive function(WCST), and brain wave(EEG). Also, exercise program was progressed 3 times a week(every 60 minutes) during totally 8 weeks. Data processing in the experimental result was used PASW-PC 18.0 statistical program. The basic test on general characteristics and psychological variables in ADHD children before exercise was carried out one-way ANOVA. Also, a change in difference according to three groups and measurement period was carried out repeated measure analysis. To correctly analyze a change by factor, the paired t-test and repeated measured one-way ANOVA were carried out. Results: The 8-week aerobic exercise participation of children with ADHD was indicated to have positive effect on a change in executive function and EEG. Also, aerobic exercise was helpful to executive function and EEG. Based upon those results, we might expect to use for relax and improvement of negative symptoms with ADHD children.
        98.
        2011.02 서비스 종료(열람 제한)
        자연재해를 비롯한 인적재난 등 방재정보에 대한 관리기관이 상이하고, 일부 보안이 요구되는 재난 정보의 특수성으로 인하여 적시적소의 자료 공유와 활용, 자료의 정확도 및 표준화 등 다양한 문제점들이 발생하고 있다. 본 연구에서는 소방방재청만의 고유주제도 개발을 위하여 기구축된 국가재난관리시스템(NDMS) 및 방재 관련 유관기관 자료에 대하여 자료 정확성 검토 및 수정작업을 수행하였으며, 이를 기초로 시범지역에 대한 방재기본도 및 방재주제도 작성을 위한 정량적 방법을 제시하였다. 아울러 구축된 방재기본도 및 방재주제도 자료들에 대한 효율적인 활용을 위하여 소방방재 지리정보시스템의 프로토타입을 개발하였다.
        99.
        2011.02 서비스 종료(열람 제한)
        최근 지구온난화와 이상기후로 대규모 자연재해가 빈번히 발생하고 있으며, 그 피해규모가 점차 대형화·광역화되고 있는 추세이다. 또한 광범위한 재난상황에 대한 신속한 대응체계의 부재로 대규모 재난으로 인한 재난현장의 상황 파악이 곤란한 실정이다. 따라서 위성영상 기반 재해우려지역의 주기적 모니터링을 통한 사전 재해위험감지 및 선제적 대응능력 강화 필요성이 대두되고 있으며, “국가우주개발중장기기본계획”에 따른 위성영상을 활용한 국가재난관리체계 구축이 요구되고 있다. 본 연구에서는 최근 빈발하고 있는 자연재해를 효과적으로 모니터링 하기 위해 위성센서와 운영체계 분석을 통해 재난대응 위성영상정보 활용성을 검토하고 위성영상을 활용한 국가재난관리 정보를 일괄·지속적으로 분석·제공·운용할 수 있는 방재위성센터 구축을 위한 단·중·장기 종합계획 수립을 통해 재난대응을 위한 위성영상정보 활용체계 구축 방안을 도출하였다.
        100.
        2011.02 서비스 종료(열람 제한)
        전 세계적으로 홍수, 지진, 지진해일 등 복합적이고 광역적인 재해·재난이 발생함에 따라 많은 인적·물적 피해가 발생하고 있으며, 이에 대한 신속한 재난대응 및 피해지역에 대한 조기분석에 대해 국내외적으로 다양한 기술개발과 재난관리 적용성에 관한 연구개발이 진행되고 있다. 그 가운데 위성영상을 활용한 분석 결과에 대한 가치와 활용도가 증가하고 있는 추세이다. 국내에서도 재해·재난분야의 위성영상 활용성을 인지하여 정부기관 고유 업무에 대한 실무적 대안 마련이 검토되고 있으며, 특히 재난발생시 위성영상 분석을 통한 의사결정지원에 대한 인식이 높아지고 있는 실정이다. 이와 관련하여 본 논문에서는 고해상상도 위성영상인 Kompsat-2 영상과 GeoEye 영상의 피해 전·후 영상을 육안 분석하여 2010년 1월 12일에 진도 7규모의 지진이 발생한 HAITI의 수도인 포르토프랭스 중심으로 건물피해 분석 및 피해밀집도를 분석하였다. 또한 이를 검증하기 위해 국외 위성영상 분석 전문기관인 UNOSAT 및 SERTIT의 영상촬영, 취득, 분석, 건물피해에 대해 비교·분석하여 결론을 도출하였다.
        1 2 3 4 5