• Journal of Power Electronics
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• 제11권4호
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• pp.418-423
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• 2011

This paper presents a simulation model and a parameter identification scheme of an induction motor drive for electric vehicle. The induction motor in automotive applications should operate in very high efficiency and achieve the maximum-torque-per-ampere (MTPA) feature even with saturated magnetic flux under very high torque. The indirect vector control which is typically adopted in traction drive system requires precise information of motor parameters, particularly rotor time constants. This work models an induction motor considering magnetic saturation and proposes an empirical identification method using the current controller in the synchronous reference frame. The proposed method is applied to a 22kW-rated induction motor for electric vehicle.

• Structural Engineering and Mechanics
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• 제71권4호
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• pp.391-405
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• 2019

Compared to the ambient vibration test mainly identifying the structural modal parameters, such as frequency, damping and mode shapes, the impact testing, which benefits from measuring both impacting forces and structural responses, has the merit to identify not only the structural modal parameters but also more detailed structural parameters, in particular flexibility. However, in traditional impact tests, an impacting hammer or artificial excitation device is employed, which restricts the efficiency of tests on various bridge structures. To resolve this problem, we propose a new method whereby a moving vehicle is taken as a continuous exciter and develop a corresponding flexibility identification theory, in which the continuous wheel forces induced by the moving vehicle is considered as structural input and the acceleration response of the bridge as the output, thus a structural flexibility matrix can be identified and then structural deflections of the bridge under arbitrary static loads can be predicted. The proposed method is more convenient, time-saving and cost-effective compared with traditional impact tests. However, because the proposed test produces a spatially continuous force while classical impact forces are spatially discrete, a new flexibility identification theory is required, and a novel structural identification method involving with equivalent load distribution, the enhanced Frequency Response Function (eFRFs) construction and modal scaling factor identification is proposed to make use of the continuous excitation force to identify the basic modal parameters as well as the structural flexibility. Laboratory and numerical examples are given, which validate the effectiveness of the proposed method. Furthermore, parametric analysis including road roughness, vehicle speed, vehicle weight, vehicle's stiffness and damping are conducted and the results obtained demonstrate that the developed method has strong robustness except that the relative error increases with the increase of measurement noise.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1667-1670
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• 1997

We consider the probelem of identifying and underwater vehicle. It is assumed that a priori information about the parameteric model structure and values of the hydrodynamic coefficients is available from some other schemes. The concept of relative esnsitivity is introduced to plan and efficinet identification procedure. An analysis of the sensitivity of the overall system to a particular hydrodynamic coefficinet provides a tool to evaluate the relative importance of the same coefficient in a particular maneuver. Then it can be made possible to reduce the filter size by selecting some dominatn hydrodynamic coefficients as parameters to be estimated for a given maneuver, and this fact may be used for establishing a gradual identification scheme. The main merit of a gradual identification is substantially reduced computer burden with increased nimerical stability. An illustrative simualtion result is given.

• 항공우주기술
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• 제7권2호
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• pp.31-37
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• 2008

항공기의 변수 추정을 위해서는 비행시험을 통해 얻어진 데이터를 이용해야한다. 비행 시험의 문제점으로 비행중에는 데이터를 재조정하기가 힘들다. 이러한 점을 감안하여 본 논문에서는 변수추정을 위한 비행시험을 대신해서 선회 비행 데이터를 사용하여 주파수영역에서 변수를 추정하는 상용화된 변수추정프로그램(CIFER)으로 스마트 무인기 40% 축소기의 동적 파라미터를 추정하였다.

• 자동차안전학회지
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• 제9권4호
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• pp.48-54
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• 2017

This paper presents the motorcycle inspection standards development on the vehicle identification, engine and transmission, tyres and wheels, steering and suspension, and brake system. 187 real-world motorcycles are visually and mechanically inspected according to the developed inspection standards. The non-compliance rate of the vehicle identification is 20.3% and main causes are insecure, damaged, and not clearly visible number plate. The non-compliance rate of the brake system is 15.5% and main cause is failing to meet the brake performance requirements. The motorcycle inspections standards are improved reflecting 187 cases of real-world motorcycle inspection results.

• 전자공학회논문지B
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• 제30B권6호
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• pp.100-108
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• 1993

In this paper, noticing the point of human's ability which appropriately cope with vague conditions, we design fuzzy traffic signal light controller similar to human's distinction ability and decide the optimum cycle most suited to any traffic junction using fuzzy identification algorithm. In this study, for the control output decision process we design fuzzy controller better than electronic vehicle actuated controller in performance. We propose the cycle decision method which is not limited by the variance of traffic junction vehicle number through overcoming the limit of Webster's method which is adopted by the fixed cycle controller. Simulated experimental results show that fuzzy controller and fuzzy identification algorithm are better than the existing electronic vehicle actuated controller and fixed cycle controller in delay time per vehicle.

• 한국정보통신학회논문지
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• 제9권1호
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• pp.160-164
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• 2005

자동차 번호판 자동인식에서 어두운 조명에서나 날씨가 좋지 않을 경ㅇ 차량의 형상이 왜곡 될 수 있고, 번호판을 식별하는데 어려움이 있다. 이에 본 논문에서는 움직이는 차량의 영상에서 흔들림이 없고, 밝은 햇빛에서 어두운 조명상태까지의 다양한 환경을 수용할 수 있는 자동차 번호판 인식방법을 제안하였다. 제안한 방법은 투시광선을 서로 다른 세기를 갖는 두 개의 빔(beam)으로 분리한 다음 CCD 카메라를 사용하여 두 개의 포착된 이미지를 조합하여 물체가 움직일 때도 동요 없는 이미지를 산출하였다. 실험결과로써 466 개의 움직이는 차량영상을 이용한 결과 98.7%의 인식률을 얻을 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권6호
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• pp.2098-2114
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• 2021

Light intensity variation is one of the key factors which affect the accuracy of vehicle face re-identification, so in order to improve the robustness of vehicle face features to light intensity variation, a Nonnegative Matrix Factorization model with the constraint of image acquisition time difference is proposed. First, the original features vectors of all pairs of positive samples which are used for training are placed in two original feature matrices respectively, where the same columns of the two matrices represent the same vehicle; Then, the new features obtained after decomposition are divided into stable and variable features proportionally, where the constraints of intra-class similarity and inter-class difference are imposed on the stable feature, and the constraint of image acquisition time difference is imposed on the variable feature; At last, vehicle face matching is achieved through calculating the cosine distance of stable features. Experimental results show that the average False Reject Rate and the average False Accept Rate of the proposed algorithm can be reduced to 0.14 and 0.11 respectively on five different datasets, and even sometimes under the large difference of light intensities, the vehicle face image can be still recognized accurately, which verifies that the extracted features have good robustness to light variation.

• 한국항공우주학회지
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• 제30권7호
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• pp.130-136
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• 2002

본 논문에서는 자동조종장치를 장착한 무인항공기의 시스템 식별을 위한 비행시험기법에 대해 기술하였다. 종운동 및 횡/방향운동 구동입력으로는 멀티스텝 입력을 이용하였다. 각 운동모드에 대해 주파수역 해석을 통해 최적의 입력시간을 설정하였다. 무인항공기의 자동조종장치를 탑재한 비행조종컴퓨터를 이용하여 프로그래밍 모드에서의 비행시험방법으로 종운동과 횡/방향운동의 분리를 통해 시스템 식별을 위한 최적의 자료를 제공하고 있다. 또한 설계치에 근사한 정확한 구동입력을 인가하여 보다 높은 입력주파수를 확보할 수 있었다. 비행시험에서는 안정된 대기상태에서 반복적인 시행을 수행하였으며, 향상된 비행체 탑재 자료저장장치를 이용하여 고품질의 비행자료를 확보하였다. 본 비행시험 기법을 적용하여 획득한 비행자료는 무인항공기의 시스템 식별을 위한 비행자료로 이용되었다.

• Structural Engineering and Mechanics
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• 제14권2호
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• pp.151-170
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• 2002

Moving force identification is a very important inverse problem in structural dynamics. Most of the identification methods are eventually converted to a linear algebraic equation set. Different ways to solve the equation set may lead to solutions with completely different levels of accuracy. Based on the measured bending moment responses of the bridge made in laboratory, this paper presented the time domain method (TDM) and frequency-time domain method (FTDM) for identifying the two moving wheel loads of a vehicle moving across a bridge. Directly calculating pseudo-inverse (PI) matrix and using the singular value decomposition (SVD) technique are adopted as means for solving the over-determined system equation in the TDM and FTDM. The effects of bridge and vehicle parameters on the TDM and FTDM are also investigated. Assessment results show that the SVD technique can effectively improve identification accuracy when using the TDM and FTDM, particularly in the case of the FTDM. This improved accuracy makes the TDM and FTDM more feasible and acceptable as methods for moving force identification.