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        검색결과 32

        22.
        2011.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study aims to provide preliminary review for standardization of methods for evaluating reduction performance of pollution-reducing building materials and to select commercially available pollution-reducing building materials for assessing their current status. The ISO 16000-23 and -24 standards were used as references for standardizing the test methods. The sub test categories—stability of the supply air concentration, type of the supply air, and supply air concentration—which were not included in the standards were selected and conducted for the purpose of this study. Five (5) wall materials and 2 ceiling materials were tested for formaldehyde reduction performance and 3 wall materials were tested for toluene reduction performance. The study included experimental review of the essential test criteria such as stability of the supply air, internal stability of the chamber, and recovery rate. The samples tested exhibited some reduction performance for formaldehyde but little reduction performance for toluene.
        4,300원
        24.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is realized that the extraterrestrial matter is in ionized state, plasma, so the matter of this kind behaves as not expected because of its sensitiveness to electric and magnetic fields and its ability to carry electric currents. This kind of subtle change can be observed by an instrument for the magnetic field measurement, the magnetometer usually mounted on the rocket and the satellite, and based on the ground observatory. The magnetometer is a useful instrument for the spacecraft attitude control and the Earth's magnetic field measurements for the scientific purpose. In this paper, we present the preliminary design and the test results of the two onboard magnetometers of KARl's (Korea Aerospace Research Institute) sounding rocket, KSR­III, which will be launched during the period of 2001-02. The KSR-III magnetometers consist of the fluxgate magnetometer, MAG/AIM (Attitude Information Magnetometer) for acquiring the rocket flight attitude information, and of the search-coil magnetometer, MAG/SIM (Scientific Investigation Magnetometer) for the observation of the Earth's magnetic field fluctuations. With the MAG/AIM, the 3-axis attitude information can be acquired by the comparison of the resulting dc magnetic vector fields with the IGRF (International Geomagnetic Reference Field). The Earth's magnetic field fluctuations ranging from 10 to 1,000 Hz can also be observed with the MAG/SIM measurement.
        4,000원
        25.
        2017.04 서비스 종료(열람 제한)
        In this study, preliminary analytical study on the middle scale impact test of SC(steel plate concrete) walls were carried out to evaluate the impact resistance performance of SC walls subjected to missile impact load. A total of 15 middle-scale impact tests will be carried out to investigate the impact behavior of SC walls. Pre-test impact analysis for all test cases were performed to decide the initial impact velocity. Calibrations of the analytical parameter were performed using preliminary test results.
        26.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        Drought is a reoccurring worldwide natural hazard that affects not only food production but also economics, health, and infrastructure. Drought monitoring is usually performed with precipitation-based indices without consideration of the actual state and amount of the land surface properties. A drought index based on the actual evapotranspiration can overcome these shortcomings. The severity of a drought can be quantified by making a spatial map. The procedure for estimating actual evapotranspiration is costly and complicated, and requires land surface information. The possibility of utilizing drone-driven remotely sensed data for actual evapotranspiration estimation was analyzed in this study. A drone collected data was used to calculate the normalized difference vegetation index (NDVI) and soil-adjusted vegetation index (SAVI). The spatial resolution was 10 m with a grid of 404 x 395. The collected data were applied and parameterized to an actual evapotranspiration estimation. The result shows that drone-based data is useful for estimating actual evapotranspiration and the corresponding drought indices.
        27.
        2012.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The problem of spacecraft attitude control is solved using an adaptive neuro-fuzzy inference system (ANFIS). An ANFIS produces a control signal for one of the three axes of a spacecraft’s body frame, so in total three ANFISs are constructed for 3-axis attitude control. The fuzzy inference system of the ANFIS is initialized using a subtractive clustering method. The ANFIS is trained by a hybrid learning algorithm using the data obtained from attitude control simulations using state-dependent Riccati equation controller. The training data set for each axis is composed of state errors for 3 axes (roll, pitch, and yaw) and a control signal for one of the 3 axes. The stability region of the ANFIS controller is estimated numerically based on Lyapunov stability theory using a numerical method to calculate Jacobian matrix. To measure the performance of the ANFIS controller, root mean square error and correlation factor are used as performance indicators. The performance is tested on two ANFIS controllers trained in different conditions. The test results show that the performance indicators are proper in the sense that the ANFIS controller with the larger stability region provides better performance according to the performance indicators.
        28.
        2010.12 KCI 등재 서비스 종료(열람 제한)
        이 연구는 칼라 디지털 카메라 영상 분석에 의한 유수분화기 벼 군락의 건물중 및 질소흡수량 추정 모델, 유수분화기 질소흡수량과 질소 수비량에 따른 유수분화기 이후 질소 흡수량 추정 모델, 유수분화기 질소 흡수량과 유수분화기 이후 질소 흡수량에 따른 수량 및 쌀 단백질함량 추정 모델을 구축하고 이를 종합하여 목표 수량 또는 단백질함량을 달성하기 위한 질소 수비량을 추천하는 원시 프로그램을 개발하여 현장 적용성 예비 검토를 실시하고자 한 것이다. 1. 군락피복도(CC)와 군락체적(CV)은 초장, 건물중 및 질소흡수량과 고도로 유의한정의 상관을 나타내었으며, R, G, B, NDI 및 명도 값은 이들과 유의한 부의 상관을 나타내었다. 한편 표준화된 색지표인 r은 잎 및 지상부 질소함량과 유의한 부의 상관을 나타내었으나 표준화 색지표 b와 g는 이들과 유의한 상관을 보이지 않았다. 2. 벼 군락의 디지털 카메라 영상분석을 이용한 벼 지상부 건물중 및 질소 흡수량을 추정하기 위한 비선형회귀 모델을 작성하였다. 지상부 건물중 추정 모텔에는 CC와 정규화된 R값(r, NorR)이 변수로 채택이 되었고, 질소흡수량 추정에는 CC와 정규화된 G값(g, NorG)이 채택되었으며, 이들 모델의 결정계수는 각각 0.81과 0.68이었다. 영성분석 색지표 이외에 초장을 모델에 도입하는 경우 모델의 결정계수는 더 높아졌다. 3. 유수분화기에 적정 질소 추비량을 처방하기 위해서는 유수분화기 식물체의 질소 영양 상태(질소 흡수량, PNup) 및 질소 시비량이 수량과 단백질함량에 미치는 영향을 정량화하여야 하는데, 이를 위하여 Npi와 PNup이 유수 분화기부터 성숙기까지의 지상부 질소흡수량에 미치는 영향 및 PNup과 PHNup이 벼 수량 및 쌀 단백질 함량에 미치는 영향을 검토하여 중회귀 모델을 작성하였으며 이 모델들은 결정계수가 모두 0.8이상으로 높았다. 4. 상기의 모델들을 종합하여 유수분화기 벼 군락 영상분석을 이용한 수비처방 원시 프로그램을 작성하여 예비 검증 실험을 하였다. 벼 수비 처방 프로그램에 의해 쌀단백질 함량 6.0%를 기준으로 처방된 수비질소 분시율이 19%~21%로 표준재배 분시율 30%에 비해 낮은 수준으로 처방되었으나 완전미 수량은 대등하였고, 단백질함량은 수비처방 목표단백질 함량 6%보다는 다소 낮은 5.7~5.8%였으며, 수량과 단백질함량의 변이 계수는 관행 수비 처방구에 비하여 프로그램 처방구에서 크게 낮아져서 프로그램 처방에 의하여 수량과 품질이 균질화되는 결과였다.
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