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        24.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper suggests a nonlinear pressure consideration scheme through an unsteady pipe network analyzer for leakage detection with a portable pressure wave generator. In order to evaluate the performance of a proposal scheme, linear input pattern has been simulated and experiments had been carried out under both no leakage and one leakage conditions in a reservoir-pipeline-valve system. This method using portable pressure wave generator showed that a leakage can be detected from a reflection where a leakage is originated through time domain analysis. Meaningful similarity in pressure response between nonlinear input pattern and experimental results were found both no leakage and a leakage conditions.
        4,000원
        28.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 가스추진 174K급 LNG 운반선의 가스 압축기실에서 발생하는 가스누출 모사를 통해 가스탐지기의 최적 위치를 분석 하였으며, 새로 개정된 IGC 코드에 명시된 안전규정을 만족하는 합리적인 방법도 함께 제안하였다. 가스압축기실에서의 LNG 가스누출 수치해석을 위해, 실제 ME-GI 엔진이 장착된 174K급 LNG 운반선의 압축기실 형상과 장비, 배관의 배치와 같은 치수로 3D 설계되었다. 가 스누설에 대한 시나리오는 305 bar의 높은 압력과 1 bar의 낮은 압력을 적용하여 진행하였다. 고압용 핀홀의 크기는 4.5, 5.0, 5.6 mm이고 저압용은 100, 140 mm이다. 해석 결과, 5.6 mm 핀홀(고압)과 100, 140 mm 핀홀(저압) 상태의 누출에 대한 환기평가에서 가연성 가스농도는 심 각한 위험이 없음을 확인하였다. 그러나 개정된 IGC 코드에 따라 설치된 압축기실의 가스 감지 센서의 실제 위치는 다른 지점으로 이동 해야 하고, 측정 지점이 현 규정에서 요구하는 것보다 더 추가되어야 함을 확인하였다.
        4,000원
        32.
        2018.10 구독 인증기관·개인회원 무료
        Although understanding dispersal ecology is important of Haemaphysalis longiconirs (Acari: Ixodidae) to control severe fever with thrombocytopenia syndrome, the small size of H. longicornis makes it challenging to study their behaviors. We examined the potential of fluorescent marking system (FMS) paired with an ultraviolet laser, an effective insect detection method, in tracking of H. longicornis. When we assessed potential effects of FMS on the survivorship and behavioral parameters including horizontal movement, vertical climbing height, and response to CO₂ of all development stages (larva, nymph, and adult) of H. longicornis, it did not induce any adverse effects on the hard ticks. Furthermore, we measured the detectable distance and detection rate of larvae, nymphs and adults to evaluate the detection efficacy of FMS. Using an ultraviolet laser, operators could detect the hard ticks from a distance ranging from 12 m (larva) to 29 m (adult). When the detection rate was measured in a grassland both during day and night, it was higher at night compared to day and increased with the body size. The detection rate was over 90% for all stages of the hard ticks at night, whereas larvae and nymphs showed that of 23% and 34% respectively during the day. However, the detection rate of adults was higher compared to other development stages regardless of time of experiment. Our results indicate that FMS can serve as a promising tool to track the hard ticks by providing reliable detection efficacy with no adverse effects on the marked individuals.
        33.
        2018.05 구독 인증기관·개인회원 무료
        Three CNN (Convolutional Neural Network) models of GoogLeNet, VGGNet, and Alexnet were evaluated to select the best deep learning based image analysis mothod that can detect pavement distresses of pothole, spalling, and punchout on expressway. Education data was obtained using pavement surface images of 11,056km length taken by Gopro camera equipped with an expressway patrol car. Also, deep learning framework of Caffe developed by Berkeley Vision and Learning Center was evaluated to use the three CNN models with other frameworks of Tensorflow developed by Google, and CNTK developed by Microsoft. After determing the optimal CNN model applicable for the distress detection, the analyzed images and corresponding GPS locations, distress sizes (greater than distress length of 150mm), required repair material quantities are trasmitted to local maintenance office using LTE wireless communication system through ICT center in Korea Expressway Corporation. It was found out that the GoogLeNet, AlexNet, and VGG-16 models coupled with the Caffe framework can detect pavement distresses by accuracy of 93%, 86%, and 72%, respectively. In addition to four distress image groups of cracking, spalling, pothole, and punchout, 22 different image groups of lane marking, grooving, patching area, joint, and so on were finally classified to improve the distress detection rate.
        34.
        2018.04 구독 인증기관·개인회원 무료
        Both a fluorescent marking system (FMS) and a portable harmonic radar system (PHRS) are effective insect tracking methods. Prior to comparing their efficacies, we tested the viability of FMS in detection of an agricultural pest, Riptortus pedestris (Hemiptera: Alydidae); previous studies showed the harmlessness of PHRS on R. pedestris and its detection distance. Fluorescent marking allowed the detection of marked R. pedestris from > 25 m, when illuminated with a laser in the dark, while affecting only the vertical walking distance of the insect. Then, we assessed the efficacy of the FMS and PHRS as well as combining both methods (BOTH) in detection of R. pedestris in a grass field and a bean field during day and night. PHRS and BOTH showed higher detection rates than FMS in all settings, except for in the bean field at night. Also, although BOTH did not enhance total detection time, it facilitated the retrieval of the sample at night compared to only using PHRS.
        35.
        2018.04 구독 인증기관 무료, 개인회원 유료
        최근에는 노후된 터널의 개수가 증가함에 따라 터널의 안전성 문제가 부각되고 있으며, 특히 안전사고가 발생하였을 때 신속하게 붕괴지점을 파악하고 붕괴된 지점에 매몰된 사람 및 장비등을 찾는 문제가 쟁점화 되고 있다. 터널의 안전성 문제를 계측하기 위한 시스템으로서 종래 기술은 주로 터널 공사 현장에서 작업자의 위치 계측이나, 공사의 진행 상황을 확인하기 위한 네트워크에 관한 것에 한정되었다. 또한 터널 안전과 관련된 시스템은 장기간 유지되어야하며 유지보수 기간이 길어야하는 특징이 있지만 기존 기술들은 배터리 소모 문제, 설치 비용 문제로 운용에 어려움이 많았다. 본 논문에서는 터널과 같은 폐쇄 구조물이 붕괴사고가 발생하였을 때 붕괴지점을 정확히 파악하고, 매몰된 사람 또는 장비등을 찾을 수 있는 모니터링 시스템을 제안하였다. 센서를 통해 터널 붕괴 지점을 인지하고, 붕괴 시점 및 붕괴 사고를 탐지하고, 사람이나 장비등의 위치 정보를 통해 정확한 매몰 위치 파악이 가능하게 하는 시스템을 제안한다. 또한 센서로부터 오는 정보를 수집하고, 기계학습 기반으로 분석하여 붕괴 사고의 징후를 예측할 수 있는 지능형 터널 붕괴 모니터링 시스템을 제안하였다.
        4,000원
        36.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We give a detailed description of the installation and operation of a double-station meteor detection system which formed part of a research & education project between Korea Astronomy Space Science Institute (KASI) and Daejeon Science Highschool. A similar system is currently not existing in South Korea. A total of six light-sensitive CCD cameras were installed with three cameras at SOAO and three cameras at BOAO observatory. A double-station observation of a meteor event enables the determination of the three-dimensional heliocentric orbit in space. This project was initiated in response to the Jinju reball event in March 2014. The cameras were installed in October/November 2014. The two stations are identical in hardware as well as software. Each station employes sensitive \Watec-902H2" cameras in combination with relatively fast f/1.2 lenses. Various elds of views were used for measuring di erences in detection rates of meteor events. We employed the SonotaCo UFO software suite for meteor detection and their subsequent analysis. The system setup as well as installation/operation experience is described and rst results are presented. We also give a brief overview of historic as well as recent meteor (fall) detections in South Korea. For more information please consult http://meteor.kasi.re.kr.
        6,300원
        37.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cherry leaf roll virus(CLRV)는 group IV positive sense ssRNA viruses, Nepovirus로 분류되는 식물병원성 바이러스이다. CLRV는 체리 등 목본 및 완두 등 콩과 작물을 자연 기주로 하며, 실험적으로 약 36개 과 이상의 넓은 기주 범위를 가지고 있어 국가적, 경제적 및 농가 개인적 피해를 야기 할 가능 성이 보고되고 있다. 현재 CLRV를 검출하는 방법으로 역전사(reverse transcription; RT)-nesdted 중 합효소연쇄반응(polymerase chain reaction; PCR) 이 활용되고 있으며, 다양한 기주로부터 CLRV를 검출하기 위해서는 검출 감도, 특이성, 반응 시간, 단순성 등이 중요 요소였다. 그러나 RT-nested PCR은 두 단계로 구성되어 있어 단순하지 않고, CLRV를 검출하는데 약 10시간 이상의 반응 시간이 소 요되었다. 이번 연구에서는 등온증폭법을 이용하여 단순하고 신속하게 CLRV를 검출하는 방법을 개발하 였다. 등온증폭 반응은 RT-nested PCR과 동등한 검출 감도로 CLRV를 검출 하였다. 그러나 반응 시간 을 약 2시간 수준으로 단축하였으며, 6개 영역을 사용하는 등온증폭 프라이머의 사용으로 더욱 특이적 으로 증폭 할 수 있었다.
        4,000원
        38.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 조타기 작동 신호에 대하여 AIS 통신을 이용하여 상호 교환함으로써 상대선의 선회정보를 보다 신속히 파악할 수 있는 선회조기감지시스템을 구축하였으며, 이를 실선에 적용하여 해당 시스템의 실효성을 검증하였다. 조타 신호가 조타기를 작동함과 동시에 AIS를 통하여 송신되어 상대선의 ECDIS에 사용된 타각만큼 유색으로 표시되는 것을 확인하였다. 선회조기감지시스템을 통하여 상대선의 변침 상황을 조기에 감지할 수 있었으며, 이를 통한 선박 상호간 충돌회피가 조기에 가능할 것으로 판단된다. 또한, 의심 선박에 대한 VTS의 적극적 관제가 가능하고, 해양안전종합정보시스템을 통한 해양사고 분석에도 활용 가능할 것이다.
        4,000원
        39.
        2016.10 구독 인증기관·개인회원 무료
        Early detection of Hanwoo cow’s estrus is an important issue in the management of group-housed livestock. In particular, failure to detect estrus in a timely and accurate way can become a limiting factor in achieving efficient reproductive performance. Although a rich variety of methods has been introduced for the detection of estrus, a more accurate and practical method is still required. The behavior of 50 estrus and 100 non estrus Hanwoo cows was video recorded and analysed in 2 Korean native cattle farm. All 50 estrus cattle (100%) showed the mounting or mounted behavior, but only 5 of 100 non estrus cattle (5%) showed the mounting or mounted behavior. One hundred and fifty Hanwoo cows with an age between 2 to 5 years that were expected to come into estrus within 3 days were randomly assigned to each compartment for the estrus group. The heated cows were video recorded for about 24 hours until after post estrus. The results showed that Hanwoo cows can be considered on estrus when it stand immobile during mounted by any other cow in more than or equal to 3.15 s and 3.22 s in chest-tail head mount and head-above back mount and that occurs consecutively at least three times within 876.4 s interval. The algorithm was also developed using the thresholds of the mount duration, mount interval and consecutive occurrence number. The Hanwoo cow’s estrus detection system using IR sensor (CEDSIRS) was composed of IR sensors, a controller, a CPU, a mobile, and so on. If total COUNT numbers per hour was above 1 and it was maintained more than 7 hours, we determined that a cow was in estrus and 16 h past the time from the first estrus detection was regarded as optimum AI time. The 55 of 57 estrus cows (96.5 %) were detected to estrus. Only 5 of 57 cows detected to estrus (8.8%) were decided to weak estrus and 2 of them were not detected. The total conception rate was 85.7%. The estimated price of CEDSIRS is 3,000,000 Won. Therefore, CEDSIRS will improve largely the average conception rate and economic benefits of Hanwoo cow farms.
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