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        검색결과 4

        1.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to review a method to estimate the average travel speed of the Bus Rapid Transit(BRT) section using the bus departure and arrival time data collected using the Korean bus information system (BIS). METHODS : To determine an average travel speed estimation model suitable for the BRT system in Korea, the speed estimated using the speed estimation model of TCQSM, which is used in the U.S., and that using the proposed speed estimation model that used the bus departure and arrival time data were compared with the actual travel speed using a t-test. RESULTS : The average travel speed estimated using the proposed method was more suitable for the actual average travel speed than that estimated using the TCQSM model. CONCLUSIONS : As a result of estimating the average travel speed, if the length of the link is 900 m, SBRT can be constructed on the existing road, but at least 1,200 m must be ensured to build SBRT in the new city. The proposed bus average travel speed estimation model can be used to review the BRT operational efficiency considering the speed limit, traffic signal, and dwelling time at bus stops in the planning and operation stages of the BRT.
        4,200원
        4.
        2020.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We have developed an algorithm for tracking coronal mass ejection (CME) propagation that allows us to estimate CME speed and its arrival time at Earth. The algorithm may be used either to forecast the CME’s arrival on the day of the forecast or to update the CME tracking information for the next day’s forecast. In our case study, we successfully tracked CME propagation using the algorithm based on g-values of interplanetary scintillation (IPS) observation provided by the Institute for Space- Earth Environmental Research (ISEE). We were able to forecast the arrival time (Δt = 0.30 h) and speed (Δv = 20 km/s) of a CME event on October 2, 2000. From the CME-interplanetary CME (ICME) pairs provided by Cane & Richardson (2003), we selected 50 events to evaluate the algorithm’s forecast capability. Average errors for arrival time and speed were 11.14 h and 310 km/s, respectively. Results demonstrated that g-values obtained continuously from any single station observation were able to be used as a proxy for CME speed. Therefore, our algorithm may give stable daily forecasts of CME position and speed during propagation in the region of 0.2–1 AU using the IPS g-values, even if IPS velocity observations are insufficient. We expect that this algorithm may be widely accepted for use in space weather forecasting in the near future.