• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.573-578
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• 1988

The objectives of this paper are to establish an equivalent magnetic circuit of the hybrid PM step motor and to apply the canonical piecewise linear eqation and the Kazenelson algorithm of solving the nonlinear magnetic circuit, so that the static holding torque and the magnetic properties of the motor are determined. The results of that are applied to the design of the hybrid step motor.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.2012-2015
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• 2002

Synchronization phenomena of chaos observed in a dual-structured system is presented. The system is consisting of two identical piecewise-linear systems and the simple coupling between the two systems enables the synchronization of the chaotic behavior. An application of the proposed dual-structure to a real power system for the parameter value identification is also presented.

• 대한전자공학회논문지
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• 제26권12호
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• pp.2001-2009
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• 1989

This study suggests the use of fuzzy model in the semiconductor devices modeling as a black box approach. When membership functions of fuzzy sets used in a fuzzy model are simple piecewise-linear functions, the fuzzy model can be reresented in a simple equation. To show that the fuzzy model can be very realistic and simple when used in semiconductor devices modeling, we construct fuzzy models for bipolar transistor, MOSFET and GaAs FET, and compare those with canonical piecewise-linear models.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.105-106
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• 2007

We present a fast reconstruction technique for elliptic objects, which can be applied to real-time computer tomography (CT) for simple geometric objects. It will be also shown that only 3 projections are needed to reconstruct an ellipse. A piecewise quadratic model is also proposed for more efficient Kalman filter based support estimation, which is used for the fast reconstruction technique. The performance of the piecewise quadratic model is compared with that of the existing piecewise linear model. Simulation results for the fast reconstruction are also presented.

• 전자공학회논문지A
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• 제31A권12호
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• pp.142-151
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• 1994

This paper proposes new algorithms to solve canonical piecewise-linear equations with linear partitions and illustrates their efficiency through the analysis of resistive network. The basic idea of the proposed algorithm is to find the best next guess, closest to the actual solution, at each Newton-Raphson (N-R) iteration by comparing the images of nest guess candidates and that of the actual solution. The proposed algorithm can reduce the number of the N-R iterations rquired for convergence greatly, compared to the actual solution, at each Newton-Raphson (N-R) iteration by comparing the images of next guess candidates and that of the actual solution. The proposed algorithm can reduce the number of the N-R iterations required for convergence greatly, compared to the Katzenelson algorithm. When applied to analyzing test circuits, the proposed algorithm required 8 to 20 times fewer N-R iterations and 5 to 10 times less CPU time than the Katzenelson algorithm, depending on the size of the circuits. The experimental results also exhibit that the efficiency of the proposed algorithm over the Katzenelson algorithm increases as the number of the piecewise-linear regions for the representation of the circuit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2516-2518
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• 2004

This paper proposes a stability condition in discrete-time affine Takagi-Sugeno (T-S) fuzzy systems with parametric uncertainties and then, introduces the design method of a fuzzy-model-based controller which guarantees the stability. The analysis is based on Lyapunov functions that are continuous and piecewise quadratic. The search for a piecewise quadratic Lyapunov function can be represented in terms of linear matrix inequalities (LMIs).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.461-467
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• 2000

Mechanical problems are basically three dimensional nonlinear dynamic problems, which makes it difficult to solve. The difficulties are tried to overcome by modeling, i.e., simplifications of the system with the assumptions or negligence of minute effects. However, the correctness or usefulness of the model should be verified through the comparison with experimental results, which is the process of physical understanding of the system. The understanding of physics of the system make it possible to design or operation of the system. The effects of clearance and friction are always difficult problems in mechanical system due to its nonlinearity. The nonlinearity comes from piecewise-linear characteristics of the stiffness and damping of the system. The modeling of piecewise-linearity and the experimental result are discussed in this paper for impact and friction oscillator and rotor rubbing problem, which is the combination of impact and friction problems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.33.1-33
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• 2001

We address a novel approach to identify a nonlinear dynamic system for Wiener models, which are composed of a linear dynamic system part followed by a nonlinear static part. The aim of system identification here is to provide the optimal mathematical model of both the linear dynamic and the nonlinear static parts in some appropriate sense. Assuming the nonlinear static part is invertible, we approximate the inverse function by a piecewise linear function. We estimate the piecewise linear inverse function by using the evolutionary computation approach such as genetic algorithm (GA) and evolution strategies (ES), while we estimate the linear dynamic system part by the least squares method. The results of numerical simulation studies indicate the usefulness of proposed approach to the Wiener model identification.

• 한국통신학회논문지
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• 제39A권6호
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• pp.322-332
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• 2014

본 논문에서는 굴곡진 도로를 구간 선형 모델로 근사화한 차선 검출 알고리즘을 제안한다. 기존의 차선 검출 알고리즘들은 지표면이 평면이라는 가정을 이용하기 때문에, 도로면이 굴곡진 실제 도로에서는 강건한 차선 검출이 어렵다. 제안하는 방법에서는 이 문제를 전체 차로를 구간으로 분할하고, 각 구간 내에서 차로를 가장 잘 근사하는 평면 차로를 구함으로써 해결한다. 이를 위해 각 구간 내에서 다양한 각도와 위치를 가지는 평면 형태의 구간 차로 후보들을 생성하였다. 구간 차로 후보들의 연결 조합 중 실제 차로에 가장 가까운 조합을 다이나믹프로그래밍을 이용하여 찾음으로써 굴곡진 차로를 근사한다. 평면 도로 뿐 아니라, 상하, 좌우의 굴곡이 있는 도로 영상으로 구성된 데이터세트에 대하여 제안하는 방법의 차선 검출 성능을 검증하였다. 평면 도로를 가정한 기존의 방법들이 80%에서 90% 초반의 검출률을 보이는 반면, 제안하는 방법은 90% 후반의 검출률을 보임을 통해 굴곡진 도로에서의 차선 검출의 강건성을 입증하였다.

• 한국전자파학회논문지
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• 제15권10호
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• pp.977-982
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• 2004

본 논문에서는 유한 시간 차분법(FDTD) 내에서 PLRC(Piecewise Linear Recursive Convolution)법을 이용한 분산성 물질에 대한 비등방성 흡수체(APML)를 제안한다. 제안된 흡수체는 비선형, 분산성 매질 해석시 무한 경계조건을 표현하기 위해 사용될 수 있다. 제안된 흡수체는 기존의 APML 정식화 과정에서 분산 특성을 고려한 것이며 PLRC법의 장점인 빠른 계산시간, 저 메모리 사용, 다극 감수율의 간편한 정식화 등의 장점을 가지고 있다. 개발된 분산성 APML은 드바이(Debye)매질과 로렌츠(Lorentz) 매질 등의 분산성 물질의 해석에 적용하였으며 수치실험을 통해 흡수경계에서 뛰어난 흡수율을 가짐을 보였다.