• 대한교통학회지
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• 제33권5호
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• pp.461-469
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• 2015

최근 차세대 고속열차에 대한 기술적 검토가 마무리됨에 따라, 실용화 방안에 대한 연구가 본격적으로 진행되고 있다. 차세대 고속열차를 도입하기 위해서는 수요예측을 통한 타당성 분석이 선행되어야 한다. 이에 본 연구에서는 차세대 고속열차 운행특성을 고려한 적정 수단분담모형을 개발하는 것을 목적으로 하고 있다. 즉, 차세대 고속열차의 경우 기존 고속열차와의 관계에 따라 다항로짓모형과 네스티드로짓모형 중 적절한 모형을 선택하는 과정이 필요하다. 수단분담모형 구축을 위해 지역 간 통행자의 통행행태 조사를 통해 현재 및 장래 수단선호도 조사를 실시하였다. 통행시간과 통행비용으로 구성된 효용함수를 추정하기 위하여 Limdep 8.0 NLOGIT 3.0 package를 이용하여 다항로짓모형과 네스티드로짓모형을 개발하였다. 구축된 각 모형의 경우 통계적 유의성은 어느 정도 확보되는 것으로 나타났다. 다만, IIA TEST에서 IV Parameter가 약 0.521로 0과 1사이에 위치하여, 향후 모형적용 시 네스티드로짓모형이 적합한 것으로 분석되었다. 또한, 차세대 고속열차가 도입될 경우 모형의 적용과정에서 국가교통DB의 수정보완 필요성과 적용방안을 제시함으로써, 합리적인 수요분석을 위한 토대를 마련하는데 기여를 할 것으로 기대된다.

• Structural Engineering and Mechanics
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• 제64권1호
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• pp.33-44
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• 2017

In this paper, the dynamic responses of train-bridge system under one-way and two-way high-speed train passing are studied. The 3D finite element modeling is used and the bridge and train are modeled considering their details. The created model is validated by the results of the dynamic field test. To study the effect of train speed, different train passing scenarios are analyzed, including one-way passing, two-way passing in different directions at same speeds, and two-way passing in different directions at different speeds. The results show that the locations of maximum acceleration are different in one-way and two-way passing modes, and the maximum values in two-way passing mode are higher than those in one-way passing mode, while the maximum accelerations in both modes are almost identical. The displacement and acceleration values in different scenarios show peaks at speeds of 260 and 120 km/h, due to the proximity of the natural frequencies of the bridge and loading frequencies of the train at these speeds.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.1-5
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• 2005

High-speed trains with maximum speed of 300km/h, named KTX, have started revenue services since April 2004. Is becoming big problem where currently the KTX train because excessive braking noise at a station platform. The KTX braking noise follows in operating mode of KTX train and important railroad station where the quality appears different, the quality against hereupon from the commerce vehicle from the research which it sees it executes and comparison to analyze.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권8호
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• pp.457-466
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• 2002

The speed and position control of SRM(Switched Reluctance Motor) needs the encoder or resolver to obtain the rotor position information. These position sensors can be affected by the EMI, dusty, and high temperature surroundings. Therefore the speed and position sensorless control has been studied widely In this paper, the binary observer of the SRM which has two feedback compensation loops to control the speed of SRM is proposed. One loop reduces the estimation error like the sliding mode observer, and the other removes the estimation error chattering occurred in the sliding mode observer. This observer is constructed on the basis of variable structure control theory and has the inertial term to exclude the chattering. This method has a good estimation performance in spite of nonlinear modeling of SRM. The advantages of the proposed method are verified experimentally.

• ETRI Journal
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• 제37권6호
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• pp.1154-1164
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• 2015

This paper proposes a fully sensorless driver for a permanent magnet synchronous motor (PMSM) integrated with a digital motor controller and an analog pre-driver, including sensing circuits and estimators. In the motor controller, a position estimator estimates the back electromotive force and rotor position using a sliding-mode observer. In the pre-driver, drivers for the power devices are designed with a level shifter and isolation technique. In addition, a current sensing circuit measures a three-phase current. All of these circuits are integrated in a single chip such that the driver achieves control of the speed with high accuracy. Using an IC fabricated using a $0.18{\mu}m$ BCDMOS process, the performance was verified experimentally. The driver showed stable operation in spite of the variation in speed and load, a similar efficiency near 1% compared to a commercial driver, a low speed error of about 0.1%, and therefore good performance for the PMSM drive.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.165-173
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• 2014

The method of emission inspection for Heavy-duty diesel vehicles has been engine speed type Lug-down 3mode. This method could bring damage to decrepit vehicles under high speed and high load condition and it could not apply the driving pattern on the road. For these reasons, this study has started to create new emission inspection which is appropriate for Korea's road infrastructure. KD 147 would be applied to light-duty diesel vehicles from july 2010 after model operations. Therefore, this study has investigated new emission inspection system for heavy-duty diesel vehicles, except for light-duty diesel vehicles. In consideration of domestic conditions to meet the new load test method in this study, the Lug-down3 mode vehicle speed method was developed for the first time in korea.

• 한국소음진동공학회논문집
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• 제14권2호
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• pp.105-110
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• 2004

The objective of this study is to obtain the instability characteristics of the plane jet impinging on circular cylinder associated with the cylinder-tone. It is found that the characteristics depends upon he ratio of the cylinder diameter to the nozzle width, D/h, and the jet velocity. When the ratio is oderate the cylinder-tone is similar to the edge-tone. With increase of the ratio, its characteristics ecomes similar to that of the plate-tone in which only the high-speed tone associated with turbulent et is generated. When D/h 〈1. the frequency range, especially the lower limit of frequency, is ignificantly influenced by the cylinder diameter. At around D/h = 1/2, while low speed tones are nduced with the antisymmetric mode of instability and affected by the vortex shedding from the ylinder, high-speed tones are generated, at first, with the symmetric mode of instability. and then, ith antisymmetric mode, as the jet velocity increases.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.984-989
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• 2008

An estimation of high-order damping in flexible multibody dynamic simulation is introduced in this paper. The suggested damping model based on the experimental modal analysis leads to more accurate correlation results comparing to the traditional linear damping model because it directly uses the modal parameters of each mode achieved from experiment even high frequency modes. The modal parameters until the 5th mode are extracted from the experimental modal testing of the flexible beam using a high speed camera. And using the measured damping ratio and natural frequency until the 5th mode, the generic damping model is constructed. Then, the ANCF (absolute Nodal Coordinate Formulation) simulation results are compared to experimental results until the 5th mode.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.813-816
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• 1999

In this paper is Proposed a VSC(variable structure controller) for a high-speed and high-precision position control of a XY Table, which is based on the PI type reaching mode. Also the comparative study between the proposed method and the conventional PID controller is presented as well. Designed and tuned under repeated experiments, the proposed method showed a better reasonable performance than PID controller in the aspect of tracking error.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권3호
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• pp.154-161
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• 2006

This paper describes the new types of ngative differential resistance (NDR) IC applications which use a monolithic quantum-effect device technology based on the RTD/HBT heterostructure design. As a digital IC, a low-power/high-speed MOBILE (MOnostable-BIstable transition Logic Element)-based D-flip flop IC operating in a non-return-to-zero (NRZ) mode is proposed and developed. The fabricated NRZ MOBILE D-flip flop shows high speed operation up to 34 Gb/s which is the highest speed to our knowledge as a MOBILE NRZ D-flip flop, implemented by the RTD/HBT technology. As an analog IC, a 14.75 GHz RTD/HBT differential-mode voltage-controlled oscillator (VCO) with extremely low power consumption and good phase noise characteristics is designed and fabricated. The VCO shows the low dc power consumption of 0.62 mW and good F.O.M of -185 dBc/Hz. Moreover, a high-speed CML-type multi-functional logic, which operates different logic function such as inverter, NAND, NOR, AND and OR in a circuit, is proposed and designed. The operation of the proposed CML-type multi-functional logic gate is simulated up to 30 Gb/s. These results indicate the potential of the RTD based ICs for high speed digital/analog applications.