• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.159-162
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• 1998

폐수의 형태 및 성장과 막의 특성에 의해 한외여과는 처리수의 직접배출 또는 재 이용을 위해 사용되고 있다. 일본의 Masuda등은 1축 RDM을 사용하여 순수에서 회전에 따른 압력 강하를 관찰하고, 또 도시 하수처리 공정의 활성슬러지를 분리하기 위해 Aqua Renaissance '90프로젝트의 일환으로 도시 하수처리에 2축 RDM이 사용되었다. 동력학적 여과의 투과모델은 김제우 등에 의해 정립된 식을 이용하여 동력학적 여과기의 투과율(J)은 일반적으로 유효압력차($\DeltaP_T$), 벌크의 농도($C_B$) 그리고 회전속도 등에 의해 결정되어진다. 기존에 제시된 회전원판 모듈의 순수 투과에서 permeate side의 저항(Rp)값은 막자체의 저항(Rm)에 비해 상대적 작아 무시되었다. 본 연구는 1축 RDM 한외여과에서 투과율에 영향을 미치는 저항(R)에서 판자체에 변형을 주어 permeate side에서 저항(Rp)에 대한 영향에 관하여 연구를 수행하였다.

• Journal of the Korean Chemical Society
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• v.22 no.6
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• pp.386-395
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• 1978

The rates of the forward mutarotation of poly(trans-5-methyl-L-proline) in trifluoro-ethanol and of the reverse mutarotation in trifluoroethanol-n-butanol (1:4 v/v) have been measured at a number of temperatures and polymer concentrations. It was found that both mutarotations are of first-order with respect to the polymer concentration. A modified Arrhenius equation to evalute the activation energy was derived for the reaction kinetics, in which the relation between the measured physical properties and concentration, and the order of tle reaction are uncertain. The activation energies for the forward and reverse mutarotation were found to be 32.5 and 33.5 kcal per residue mole, respectively, which are about 10 kcal per residue mole higher than the $E_a$ for the mutarotation of polyproline (the resonance energy of amide bonds). The excessive quantity of the activation energy was attributed to the steric barrier between carbonyl and methyl groups during the cis-trans isomerization of amide bonds in the polymer.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.1
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• pp.23-31
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• 2011

In this paper, the intelligent smart monitor system is implemented for the next generation vehicle. to mitigate the numerous effects of distractions within the vehicle, it is vital to put critical information where the driver can use it without affection focus on the road ahead. Audible alarms are useful supplements when used in conjunction with visual displays. But driving is an overwhelmingly visual task. To optimize a vehicle's active safety systems, more than just audible alarms are necessary. The driver needs a visual interface that focuses his or her attention on the road ahead. The most commonly viewed information in a vehicle is from the instrument cluster, where speed, tachometer, fuel, engine temperature, fuel gauge, turn indicators and warning lights provide the driver with an array of fundamental information. TFT LCD, LCD Back light led, plane mirror, lens and controllers parts were designed to intelligent integrated smart monitor system. Finally, in this paper, we analyze intelligent integrated smart monitor system for driver safety vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.9
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• pp.681-689
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• 2020

This paper presents methods and results of both flight test examining roll angle estimation performance of slowly rolling munition forced to spin in the air, and fabricating a replica of guided munition. Guided munition was deployed from multi rotor type UAV mother ship whose altitude and velocity was conveyed to it as initial state. Flight test scenario is composed of a sequence of munition drop(deployment), munition spin, roll angle estimation and stabilization. Munition was deployed from mother ship at around 200m high with horizontal velocity of 15m/s, and was made spun using internal reaction wheel. Performance analysis on roll angle estimation is provided in comparison with commercial aerospace graded GPS/INS. Moreover, several mechanisms that rotates munition using reaction wheel, and actual product that realizes one of them are introduced.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1036-1037
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• 2015

지상1차 선형동기전동기는 속도와 위치센서가 회전축에 설 부착되어져 있는 회전형 동기전동기와 달리 가이드웨이를 따라 위치센서 관련부품이 설치되어져 있다. 차상 자기부상열차로부터 전송되는 위치신호는 지상 추진인버터의 실시간 추진제어에 필요한 정보에 미흡하다. 본 논문에서는 지상1차 선형동기전동기를 구동하는 추진인버터에 대한 위치신호 추정기에 대하여 제시하였다. 지상 추진인버터가 요구하는 수준의 높은 분해능의 위치신호를 얻기위하여 직류모터 모델의 블록선도로부터 폐루프 위치관측기를 설계하고 시뮬레이션 및 실험을 통해 가용 성능 확인하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.1
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• pp.57-64
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• 2021

The speed change lane is installed at the point where the roads are connected on the urban roads, reducing the relative speed to facilitate traffic communication. However, in the case of the speed limit of 30 km/h in accordance with the implementation of the safe speed "5030" in the city, the standard is ambiguous, and there are criticisms about the installation of the transmission lane. This study conducted a pilot study on the traffic patterns of the speed change lanes, focusing on the section where the safe speed "5030" policy was scheduled to be implemented after theoretical consideration of the speed change lanes. After on-site investigation, as a result of analyzing the traffic pattern according to the travel speed of the main road according to road conditions and traffic conditions, the effectiveness of the speed change lane according to the safety speed "5030" was analyzed. In this study, the installation criteria for speed change lane by speed were presented. The criteria is that "speed change lanes should not be installed when the speed limit is 30 km/h, and speed change lanes should be installed when the speed limit is 50 km/h." The criteria will be considered as a reference when establishing engineering standards for connection of other facilities in urban areas in the future. It is expected that unnecessary restrictions on individuals' exercise of private property rights will be minimized, smooth traffic flow and secure safety by the installation of speed change lanes and expansion of turning radius.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.80-89
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• 2016

The median exclusive bus lanes with the purpose of improving public transport as part of a public transport promoting policy propel to improves the speed of the bus and guarantee punctuality security of public transportation for citizen satisfaction. In Median Exclusive bus lanes, Intersection operational methods are classified as turn prohibition, left turn, left turn U-Turn after turn prohibition. However, there are not clear criteria for applying for turn left U-Turn and related researches. The purpose of this study is to search a method for more safely operation when we operate turn left U-Turn in median exclusive bus lanes intersection. As a result, Bus stop in median exclusive bus lane should set back 12m for left turn, 17m for left turn U-turn during 60km/h and set back 13m for left turn, 17m for left turn U-turn during 50km/h.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.77-83
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• 2011

This study deals with the effectiveness of roundabout. The goal is to comparatively analyze the operational effectiveness related to the conversion of rotary to roundabout in Korea. In pursuing the above, this study gives particular attentions to investigating the existing 20 rotaries and developing the networks of before-and-after improvement using VISSIM, and comparatively analyzing the effectiveness. The domestic rotaries were analyzed to need many improvements of geometric structure for the effective operation of roundabout. The main results are as follow. First, when the present condition of traffic volume were applied, the operational effect of rotary were evaluated to be better than roundabout, but the difference analyzed to be small. Second, the average delay per vehicle in the rotaries of urban area were analyzed to rapidly increase according to the growth of traffic volume. Finally, the average speed of roundabout were evaluated to be less (about 10km/h) than that of rotary, because the traffic volume of rural area were less than that of urban area.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.115-124
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• 2001

In this paper, authors propose a new nonlinear rotor flux observer for rotor field oriented control of an induction motor which is designed based on the extended Luenberger Observer theory. Extended Luenberger Observer requires minimal solution of nonlinear partial differential equation on its coordinate transformation and linearization needed on a nonlinear observer design in general. The proposed rotor flux observer is derived from the 2 phase model of induction motor on the orthogonal coordination and it has the reduce gain matrix. Simulation and experimentation were performed under the conventional indirect vector control and direct vector control with the proposed observer at different rotor resistance. Simulation results show that the convergence of the proposed observer is influenced by the chosen eigenvalues. Experimentation results on load operation show the direct vector control with the proposed observer is better than the indirect vector control to maintain the characteristics of the vector control.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.1
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• pp.1-11
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• 2012

Performance analysis was performed for an autorotating rotor. For a given airspeed, shaft angle, and collective pitch, the steady state of autorotation was judged by using the transient simulation method(TSM), then the thrust, lift, and drag coefficient for that state were computed. Average thrust was calculated from the instantaneous thrusts, in which the TSM was used in blade thrust integration. The analysis method was applied to the model rotor that had been tested by wind tunnel. Some comparison between analysis and test was provided. Two types of two-dimensional airfoil aerodynamic data were utilized in analysis, and they were made by Navier-Stokes Solver in terms of Reynolds and Reynolds-Mach number. The quantitative difference of results using two data set was examined and compared.