• Title/Summary/Keyword: Rising Time

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A Study on the Development of Decision Support Program for the Survey of Land Supply and Demand (토지 공급 및 수요조사를 위한 의사결정지원 프로그램 구축 연구)

  • Lee, Sanghun;Kim, Misuk;Lee, Yunsang
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.14 no.2
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    • pp.79-90
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    • 2018
  • This study aims to provide the system to help decision making by finding key indicators used in land supply and demand surveys, and by developing storage priority areas and projects. As problems arose such as the rising cost of public projects or disruptions to business progress due to the rapid rise in land prices and the cost of compensation for public projects in the past, a new land policy was adopted and the land reserve system was established in 2009. At that time, The bank's goal was to conserve 2 trillion won of land per year, but the result was sluggish as it accumulated a total of 1.6 trillion won from 2009 to 2015. The reason for this sluggish result is that the type and quantity of indicators are still extensive and the survey of land supply and demand has a problem of poor utilization. In order to make up for the sluggishness, we made key indicators used in land supply and demand surveys using the question investigation, and analyzed the priority of the project areas. This study provide the system to help decision making by finding key indicators used in land supply and demand surveys, and the priorities of project areas.

Physics of Solar Flares

  • Magara, Tetsuya
    • Bulletin of the Korean Space Science Society
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    • 2010.04a
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    • pp.25.1-25.1
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    • 2010
  • This talk outlines the current understanding of solar flares, mainly focusing on magnetohydrodynamic (MHD) processes. A flare causes plasma heating, mass ejection, and particle acceleration that generates high-energy particles. The key physical processes related to a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence), formation of current-concentrated areas (current sheets) in the corona, and magnetic reconnection proceeding in current sheets that causes shock heating, mass ejection, and particle acceleration. A flare starts with the dissipation of electric currents in the corona, followed by various dynamic processes which affect lower atmospheres such as the chromosphere and photosphere. In order to understand the physical mechanism for producing a flare, theoretical modeling has been developed, in which numerical simulation is a strong tool reproducing the time-dependent, nonlinear evolution of plasma before and after the onset of a flare. In this talk we review various models of a flare proposed so far, explaining key features of these models. We show observed properties of flares, and then discuss the processes of energy build-up, release, and transport, all of which are responsible for producing a flare. We come to a concluding view that flares are the manifestation of recovering and ejecting processes of a global magnetic flux tube in the solar atmosphere, which was disrupted via interaction with convective plasma while it was rising through the convection zone.

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Analysis of An Improved Short-circuit Protection for Multilevel PWM ac/dc Converter (멀티레벨 PWM ac/dc 컨버터의 향상된 단락보호기법 해석)

  • Kang S. K.;Nho E. C.;Kim I. D.;Joe C. J.;Chun T. W.;Kim H. G.
    • Proceedings of the KIPE Conference
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    • 2001.07a
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    • pp.193-196
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    • 2001
  • This paper describes an improved short-circuit protection for a multilevel ac/dc power converter The output do power of the proposed converter can be disconnected from the load within several hundred microseconds at the instant of short-circuit fault. Once the fault has been cleared the dc power is reapplied to the load. The rising time of the do load voltage is as small as several hundred microseconds, and there is no overshoot of the dc voltage because the do output capacitors hold undischarged state. Therefore, the proposed converter can be used for a power supply, which requires a rapid disconnection of the load from the power supply in the case of a short circuit, as well as a rapid connection the load to the power supply after the clearance of the short circuit condition.

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Improving Traffic Infrastructure in a Developing Country: An Investigation into the Usage of Public Bus Transport in Malaysia

  • Soh, Keng Lin;Wong, Wai Peng;Chong, Chu Le;Hiew, Yan Hwan
    • Industrial Engineering and Management Systems
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    • v.13 no.2
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    • pp.172-184
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    • 2014
  • Economic growth with rising household income has put more vehicles on the roads worsening traffic congestion, road accidents, and air and noise pollution. This situation is further aggravated by the potential working population who choose to drive to work instead of taking public transportation. Public bus transport (PBT) plays an important role in alleviating these problems. PBT is underutilized in Malaysia, and there is an opportunity to increase ridership without substantial investment. Therefore, this study was conducted to investigate the factors that influence the use of PBT in Malaysia. The data were collected using structured questionnaires from 400 respondents. The results of the analysis show that the twin factors consisting of perceived satisfaction of and perceived importance by users towards safety and comfort of facilities and services offered by PBT are significantly related to intention to use those services. The satisfaction of availability of season tickets, the importance of reliability of bus schedule and time table, and the importance of ticket pricing are also significant. By providing insights for both public bus operators and the government, this paper contributes to mitigate the underutilization of PBT in Malaysia and the consequences of putting more vehicles on the roads. From the theory perspective, this paper also contributes by extending the theory of reasoned-action to transportation studies.

A Study of Discharge Shape Changes by Magnet Arrangements in a Magnetron Cathode (마그네트론 음극의 자석 배열에 따른 방전의 형상 변화 연구)

  • Jee, Jung-Eun;Joo, Jung-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.41 no.3
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    • pp.94-101
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    • 2008
  • A new convenient magnet array module is designed to investigate effects of magnetic field array on magnetron discharge characteristics. Magnetic field analysis showed good agreement of measured discharge region by a CCD device which has a high quantum efficiency over visible wavelength range. OES (optical emission spectroscopy) showed major emission peaks are from electronic transitions in 400 nm range and 800 nm range. Effects of driving voltage characteristics were analyzed in a point of electron drift trajectories and ionizing collision frequencies. Pulsed dc with a fast rising and falling time was analyzed to have potential to increase ionization collisions by putting a burst of hot electrons and to raise sheath potential. From measured voltage and current waveform, maximum of -1000 V peak was generated with $-400\;V_{rms}$ conditions. Possibility of a properly designed magnetron cathode was shown to be used as a melting device. Cu was successfully melted with power density of a several tens of $W/cm^2$.

Life Time Diagnosis and Partial Discharge Characteristics due to shift of Void Position in XLPE (XLPE 내부 보이드 위치변화에 따른 부분방전 특성 및 수명예측)

  • Kim, Tag-Yong;Cho, Kyung-Soon;Shin, Hyun-Taek;Kim, Kwi-Yeol;Lee, Kang-Sung;Lee, Chung-Ho;Hong, Jin-Woong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.256-257
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    • 2005
  • To estimate a electrical performance of the extra high voltage XLPE cable the discharge properties due to shift of void position were investigated. The $\Phi-q-n$ properties have been measured at room temperature by rising voltage ratio of 0.5[kV]. An obtained data was stored to personal computer through A/D converter. The period of applied wave form and discharge values were divided into 64 parts and discharge values generated during 10 seconds were accumulated by phases. As a result, it was confirmed that the charge, phase angle and counts of discharge changed due to void position.

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A Kinematical Analysis of the Kenmotsu on the Parallel Bars (평행봉 Kenmotsu 동작의 운동학적 분석)

  • Kong, Tae-Ung;Kim, Young-Sun;Yoon, Chang-Sun
    • Korean Journal of Applied Biomechanics
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    • v.15 no.3
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    • pp.61-70
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    • 2005
  • The purpose of study was to investigate the kinematic variables of Kenmotsu motion in Parallel bars. To this study, by 3 dimensional kinematical analysis of 4 male national gymnasts participants in the 28th Athens Olympic Game in 2004, kinematic data collected using video camera. Coordinate data were smoothed by using a fourth-order Butterworth low pass digital filter with cutoff frequency of 6Hz. The conclusions were as follows. 1. In P2, because the constrained swing movement made the movement of a rising back difficult7, the movements of Reg. were performed at low position after Air phase. 2. In E5 event, for the shake of a stable handstand and applied techniques like a Belle(E-value), a Belle Piked(super E-value), a vertical velocity in E2, a horizontal velocity in E3 and a vertical velocity in E4 were necessary for high velocities. 3. In E4 event, it was appeared that for a flexible body's movement of a vertical up-flight, the large angle of the shoulder joint and the flexion & extension of the hip joint were necessary in Air phase and a long flight time and vertical displacement made Reg. movements stable at the high position.

The Implementation of Current Compensation Controller in Driving Voltage type Converter considering the Unbalance of Reactor at the Source Side (전원측 리액터 불평형을 고려한 전압형 컨버터의 전류 보상 제어기 구현)

  • Chun Ji-Yong;Cho Yu-Hwan;Lee Geun-Hong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.5 no.5
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    • pp.413-420
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    • 2004
  • In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining method of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. In order to solve the problem which the unbalanced system control is used to leakage transformer not equaled reactance by each phase in rectifier system. The proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.

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Prediction of the Salinization in Reclaimed Land by Soil and Groundwater Characteristics

  • Jeon, Jihun;Kim, Donggeun;Kim, Taejin;Kim, Keesung;Jung, Hosup;Son, Younghwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.63 no.6
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    • pp.131-140
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    • 2021
  • It is becoming more important to utilize reclaimed lands in South Korea, due to the increasing competition for its usage among different sectors. However, the high groundwater level and poor permeability are exposing them to deterioration by salinization. Salinization is difficult to predict because the pattern changes according to various characteristics of soil and groundwater. In this study, the capillary rising time was studied by the water content profile in the soil. The prediction equation of soil salinity was developed based on simulation result of the CHEMFLO model. to enable prediction considering various soil water content and groundwater level. The two terms constituting the equation showed the coefficients of determination of 0.9816 and 0.9824, respectively. Using the prediction equation of the study, the surface salinity can be easily predicted from the initial surface salinity and the salinity of the groundwater. In the future, more precise predictions will be possible with the results of studies on the hydraulic characteristics of various reclaimed soils, changes in water content profile by seasonal and climate events.

Analyzing Sport Documentary Online - Focus on All or Nothing: Manchester City on Prime Video

  • Han, Sukhee
    • International journal of advanced smart convergence
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    • v.8 no.3
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    • pp.20-26
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    • 2019
  • This study multi-dimensionally analyzes a sport documentary, All or Nothing: Manchester City, which is an original content on Prime Video, an American Over-The-Top (OTT) platform. Due to the success of South Korean soccer player Heung-min Son who plays Tottenham Hotspur of England, the popularity of the English Premier league is recently the greatest in South Korea along with the fact that soccer has been a popular sport for a long time. This study focuses on the success of the soccer club, Manchester City, which has become a rising star with its huge investment from United Arab Emirates; Manchester City won the league four times since 1992/1993 season. Also, during the 2017/2018 season, the background the documentary, Manchester City won the league title with new records, which shows the greatness of Manchester City. Especially, this study examines the documentary by 1) Story 2) Type of Scene 3) How to watch. Thus, this study explores not only the aspects of team-themed sport documentary that shows how and why Manchester City is excellent, but also the traits of the original content that explores the structure of the media platform.