• 조명전기설비학회논문지
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• 제17권5호
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• pp.141-148
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• 2003

최근 자동제어 시스템의 다양한 분야에서 선형운동용 디지털 액튜에이터인 하이브리드형 선형 스텝핑 전동기(HLSM)의 필요성이 증대되고 있다. HLSM은 기계적인 운동변환기구가 필요하지 않는 직접 구동방식이기 때문에 효율과 경제적인 측면에서 회전형 스텝핑 전동기에 비해 매우 유리한 장점이 있다. 본 논문에서는 현재 가장 많이 연구되고 있는 자속종방향(LFM)형 HLSM의 개발을 위하여 2차원 유한요소법(FEM)으로 최적의 치 형상을 설계하고 추력과 수직력을 계산하였다. 그리고 직접 LFM형 HLSM의 시작기를 제작하고, LFM형 HLSM의 추력 특성을 실험하였다.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.292-304
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• 2005

In this paper we present the linearized equations of motion for a bicycle as a benchmark. The results obtained by pencil-and-paper and two programs are compared. The bicycle model we consider here consists of four rigid bodies, viz. a rear frame, a front frame being the front fork and handlebar assembly, a rear wheel and a front wheel, which are connected by revolute joints. The contact between the knife-edge wheels and the flat level surface is modelled by holonomic constraints in the normal direction and by non-holonomic constraints in the longitudinal and lateral direction. The rider is rigidly attached to the rear frame with hands free from the handlebar. This system has three degrees of freedom, the roll, the steer, and the forward speed. For the benchmark we consider the linearized equations for small perturbations of the upright steady forward motion. The entries of the matrices of these equations form the basis for comparison. Three diffrent kinds of methods to obtain the results are compared : pencil-and-paper, the numeric multibody dynamics program SPACAR, and the symbolic software system Auto Sim. Because the results of the three methods are the same within the machine round-off error, we assume that the results are correct and can be used as a bicycle dynamics benchmark.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.635-637
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• 2000

To analyze the transient state of an induction motor, there have been studies for using the magnetic equivalent circuit method (MECM) instead of the time differential finite-element method, MECM which analyzes magnetic equivalent circuits after converting each part of an electric machine into the magnetic circuit elements. has the merits of short calculation-time and comparatively accurate results. To analyze an electric machine with MECM, we have to replace stator and rotor with the magnetic elements and express the air gap, where electromechanical energy conversion takes place, with the permeance. So in this paper, to analyze an Induction Motor with MECM, we express the magnetic equivalent circuit as algebraic equations and then as the matrix for solving easily them.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.330-332
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• 2000

To analyze the transient state of an induction motor, there have been studies for using the magnetic equivalent circuit method(MECD) instead of the time differential finite-element method. MECD which analyzes magnetic equivalent circuits after converting each part of an electric machine into the magnetic circuit elements, has the merits of short calculation-time and comparatively accurate results. To analyze an electric machine with MECM, we have to replace stator and rotor with the magnetic elements and express the air gap, where electromechanical energy conversion takes place, with the permeance. So in this study, to analyze an Induction Motor with HECM, we express the magnetic equivalent circuit as algebraic equations and then as the matrix for solving easily them. In particular, all relations are formed with matrixes to solve Mathematically them in the programming process later. As a result, this theory will be the basis on the static and dynamic analysis of an Induction Motor.

• Journal of Information Processing Systems
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• 제13권5호
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• pp.1135-1148
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• 2017

Speech recognition is one of the fascinating fields in the area of Computer science. Accuracy of speech recognition system may reduce due to the presence of noise present in speech signal. Therefore noise removal is an essential step in Automatic Speech Recognition (ASR) system and this paper proposes a new technique called combined thresholding for noise removal. Feature extraction is process of converting acoustic signal into most valuable set of parameters. This paper also concentrates on improving Mel Frequency Cepstral Coefficients (MFCC) features by introducing Discrete Wavelet Packet Transform (DWPT) in the place of Discrete Fourier Transformation (DFT) block to provide an efficient signal analysis. The feature vector is varied in size, for choosing the correct length of feature vector Self Organizing Map (SOM) is used. As a single classifier does not provide enough accuracy, so this research proposes an Ensemble Support Vector Machine (ESVM) classifier where the fixed length feature vector from SOM is given as input, termed as ESVM_SOM. The experimental results showed that the proposed methods provide better results than the existing methods.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.230-234
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• 1997

Reverse engineering involves digitizing a three-dimensional model or part converting the data to a CAD database description and manufacturing by CNC. Currently, the digitization is done through measurements taken manually by a CMM or touch probe mounted on a CNC machinetool. Some reverse engineering techniques require close integration between the data collection method and the surface-fitting algorithms. Accurate surface data are collected by input to the surface fitting method. This study has been found that both the smoothness of surfaces and accuracy of surface fitting are related with the degree of the interpolated surfaces.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 춘계학술발표논문집
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• pp.124-131
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• 2006

It is well known that smoother surface in substrate for coating or converting can obtain better results. Generally paper substrate is taking machine calendar process in papermaking system to give more uniformity and to get better coating runnability. This paper was prepared to find better idea for obtaining smoother surface after precalendering precoated paper as a substrate of double coating system. It was shown precalendering had effect on roughness improvement for precoating layer but was difficult to say it was effected to supercalendering results for double coating. The porosity and ink evaluation with precalendered double coated paper is needed to identify more essential clue for precalendering effect.

• 대한기계학회논문집A
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• 제30권5호
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• pp.609-614
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• 2006

Recently linear motor has been used mainly for high speed feeding performance of machine tools. The advantages of linear motor are not only high speed but high accuracy, because it is not required the coupling and ballscrew for converting rotary to liner motion. Before applying in different moving system, the dynamometer is necessary to test the performance. In Korea, the linear motor is producing in a couple of company However, the liner motor dynamometer is not commercialized yet, like as rotary motor dynamometer. In this paper, a linear motor dynamometer is designed and manufactured using a MR damper. The dynamometer system developed in this study could be used for testing the positioning accuracy fur different loading conditions, traction forces, dynamic performance and so on.

• 한국공작기계학회논문집
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• 제11권1호
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• pp.61-69
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• 2002

This paper describes a converting algorithm between programmable languages of a software PLU. It is based on IEC 61131-3 standard and PC. The proposed control logic is designed by the software model and common element with data type, variables, POUs(program organization unit) and execution control unit commonly used within programmable languages of IEC 61131-3 Standard. The generation method of object file is proposed on five programmable language based on IEC 61131-3. It is represented as fo11ows; 1) the generation method using conversion algorithm from LD to IL with FBD(function block diagram), 2) the generation method using f code generation algorithm from SFC using the SFC execution sequence with FBD and ST(structured text). The proposed control logic generator was implemented by Visual C++ 6.0 and MFC on MS-windows NT 4.0.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.213-215
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• 2006

A static frequency converter(SFC) in a pumped storage power plant is important equipment for converting electric motor kinetic energy into electric Bower. A SFC monitoring system consists of high voltage thyristor firing equipment, fault detection module, data gathering module, real time data processing equipment and man machine Interface system. This paper describes SFC system overview, developed SFC monitoring system configuration including system characteristics. and successful application result to San-Cheong pumped storage power plant.