• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.16 no.5
• /
• pp.45-52
• /
• 2002

This paper presents fault detection scheme of Brushless DC(BLDC) motor drive system by estimating BLDC motor resistance using motor input and output data which is transmitted from data acquisition board to host computer over serial communication channel. Since communication time delay has a serious effect on performance, we use periodic and fixed communication protocol. Hence, the delay time is priory known. Simplified BLDC motor model and recursive least square algorithm is used for estimating motor resistance. By experiment result, we confirm the proposed scheme.

• Journal of the Korea Computer Graphics Society
• /
• v.5 no.2
• /
• pp.1-7
• /
• 1999

We present an algorithm to reconstruct a pipe surface from a set of unorganized points. A pipe surface is defined by a spine curve and a radius of a swept sphere. In this paper, by using the shrinking and moving least-squares methods, a point cloud is reduced to a thin curve-like point set that can be easily approximated with a spine curve of a pipe surface. The distance between a point in the thin point cloud and a corresponding point in the original point set represents the radius of a swept sphere of a pipe surface.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.2
• /
• pp.164-171
• /
• 2009

This paper presents new learning algorithm of dynamic Bayesian networks (DBN) by means of constrained least square (LS) estimation algorithm and gradient descent method. First, we propose constrained LS based parameter estimation for a Markov chain (MC) model given observation data sets. Next, a gradient descent optimization is utilized for online estimation of a hidden Markov model (HMM), which is bi-linearly constructed by adding an observation variable to a MC model. We achieve numerical simulations to prove its reliability and superiority in which a series of non stationary random signal is applied for the DBN models respectively.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1865_1866
• /
• 2009

본 연구에서는 복잡하고 비선형 시스템의 모델을 동정하기 위해 Information Granulation에 기반한 퍼지추론 시스템의 새로운 범주를 소개한다. Information Granulation은 근접성, 유사성 EH는 기능성 등에 인하여 서로 결합되는 대상(특히, 데이터)의 연결된 모임으로 간주된다. HCM클러스터링에 의한 Information Granulation은 퍼지 규칙의 전반부 및 후반부에서 사용되는 멤버쉽 함수의 초기 정점과 다항식함수의 초기 값과 같은 퍼지 모델의 초기 파라미터를 결정하는데 도움을 준다. 그리고 초기 파라미터는 PSO 알고리즘과 최소자승법에 의해 효과적으로 동조된다. 제안된 모델은 Box와 jenkins가 사용한 가스로 공정[6]을 모델링하여 기존 퍼지 모델링 방법과 비교 평가한다.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1794_1795
• /
• 2009

본 논문에서는 안정도 단계(degree of stability)가 고려된 LQ 최적 제어에 대한 근사 다이나믹 프로그래밍 기법을 제안한다. 제안된 근사 다이나믹 프로그래밍 기법은 시스템 행렬(system matrix)를 모르는 경우에도 구현할 수 있으며, 특정 조건하에서 수렴성을 가짐을 수학적으로 증명하였다. 또한 제안된 알고리즘을 토대로 하는 최소 자승법 기반 실시간 구현 방법에 대해 소개하였으며, 컴퓨터 모의 실험을 통해 제안된 근사 다이나믹 프로그래밍의 성능을 입증하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.2
• /
• pp.26-30
• /
• 2000

In this paper, we obtain a mathematical model of a gas turbine control system from experimental data. The gas turbine in Gunsan power plant is selected as controlled system. The recursive least square algorithm is used to model the plant. For parameter estimation, plant is assumed as second order system and forgetting factor is 0.98 and the period of input and output signal period is 1sec. As a result, input and output characteristics of real system and modeling are identified.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.14-15
• /
• 2006

A saturation of magnetic flux in the core may occur when a large primary current flows when the iron-cored current transformer is used. This saturation makes the distorted secondary current of the CT. the distorted secondary current may cause the mal-operation or operation time delay of protective relays. CT compensation algorithm using The LSQ(Least Square) fitting method has a problem. It needs to acquire enough data for executing this algorithm without an error. In this paper, an enhanced algorithm using interpolation based LSQ(Least Square) Fitting Method is proposed. The Lagrange Interpolation Method is used for the interpolation and CT is simulated by EMTP. The results show that the proposed algorithm can accurately compensate a distorted secondary current more than existing Algorithm when the saturation severely occurs.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.199-201
• /
• 2006

풍력발전기에 있어서 블레이드의 Yaw방향 제어는 끊임없이 변화하는 풍향에 대해 효율의 극대화와 블레이드의 강도 및 진동측면에서 대단히 중요하다. 기존의 블레이드 Yaw 방향 측정은 접촉 및 비접촉 센서가 이용되어왔다. 본 논문에서는 풍력발전기의 원격모니터링 시스템에서 기본적으로 설치되는 카메라를 이용하여 블레이드의 Yaw방향을 측정하는 방법을 제안한다. 블레이드가 풍향에 따라 회전할 때 영상 누적을 행하고, 누적영상에 대해 경계점을 추정하여 타원의 궤적을 추정한다. 추정된 경계점들을 이용하고 최소자승법을 적용하여 타원방정식을 추정하고, 장축과 단축을 연산한다. 장축과 단축의 변화를 이용하여 카메라의 촬영방향의 기준점으로부터 Yaw방향의 변화를 정량적인 값으로 산출하여 이를 바탕으로 Yaw회전각을 추정한다. Yaw 방향 추정의 검증을 위해 블레이드 속도와 Yaw 방향의 제어가 가능한 모형풍력발전기를 제작하고 실험을 통하여 제안한 추정알고리즘의 유효성을 검증한다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.2
• /
• pp.346-355
• /
• 2002

This study will offer multimodal recognition instead of an existing monomodal bioinfomatics by using face, lips, to improve the accuracy of recognition. Each bioinfomatics vector can be found by the following ways. For a face, the feature is calculated by principal component analysis with wavelet multiresolution. For a lip, a filter is used to find out an equation to calculate the edges of the lips first. Then by using a thinning image and least square method, an equation factor can be drawn. A voice recognition is found with MFCC by using mel frequency. We＇ve sorted backpropagation neural network and experimented with the inputs used above. Based on the experimental results we discuss the advantage and efficiency.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.203-205
• /
• 2002

This paper presents the fault location estimation algorithm in transmission line using a recursive least square error method (RLSE). To minimize the computational burden of the digital relay a RLSE approach is used. Computer simulation results of the RLSE algorithm seem promising, indicating that it should be considered for further testing and evaluation.