• Journal of Electrical Engineering and Technology
• /
• v.1 no.2
• /
• pp.226-232
• /
• 2006

This paper presents the parameter measurement methods for high performance drive of induction motors, which are suitable for the self-commissioning function of commercial inverters. In this study, some factors that affect the accuracy of parameter measurement are examined. Measuring methods and conditions that are best fit to each parameter measurement procedure are then proposed. All the measurement procedures can be done without any auxiliary equipment, so that those can be easily adopted as self-commissioning functions of commercial inverters. To improve the measuring accuracy, least square approximation methods are adopted during the measurement procedure. The validity of the proposed methods are confirmed through experiments.

• 전기의세계
• /
• v.22 no.1
• /
• pp.42-51
• /
• 1973

The contriving equivalent circuit of single phase induction motor which does not separate the primary leakage reactance and the secondary leakage reactance by the revolving field theory, and the graphically calculating method of the characteristics with T-type circle diagram of three phase induction motor which does not suppose the primary leakage reactance can be drawn up only by the no load test, the lock test, and measuring the resistance of stator winding are suggested in this paper. The method which can calculate the parameters of the equivalent circuit and the characteristics with no load test, lock test and measuring resistance of stator windings is suggested in this paper. Considered the exciting current in lock test, we could calculate very accurate characteristics of the single phase induction motor.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.5
• /
• pp.7-13
• /
• 2010

The integrity and accuracy of the drilling hole are decided by positional error, diameter error, the roundness, the straightness, the cylindericity, size of the burr, the surface roundness and others. Among these parameters, positional error and diameter error have the most important parameters. The diameter error has been widely studied, but there has been little research done about the positional error due to the difficulty of measuring it. The measurement of hole location and diameter would be performed by CMM(Coordinate Measurement Machine). However, the usage of CMM requires much time and cost. In order to overcome the difficulties, we have developed a hole location and diameter error measuring device using machine vision. The developed measurement device attached to a CNC machine can determine hole quality quickly and easily.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.866-870
• /
• 2001

Measurement techniques for in-duct acoustic source parameters can be classified into the direct method and the load method, according to whether it utilizes an extra external source or not. It is reported that the load methods yield the negative source resistance and the purpose of this paper is to clarify that the time-varying nature of the source is the main cause of this physically implausible result. For this purpose, the direct and load methods for measuring the source characteristics of a simplified fluid machine are simulated using the time domain numerical analysis. In the numerical simulations, the method of characteristics is employed and the source characteristics are calculated from the resultant data. It is shown that the load method results in negative source resistance for some frequencies, whereas the direct method yields positive values for all frequencies considered. It is found that the result of load method is quite sensitive to the change of cylinder pressure or valve profile in contrast to the direct method.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.54 no.11
• /
• pp.680-688
• /
• 2005

The electrical current generated by heart creates not only electric potential but also a magnetic field. We have observed electrophysiological phenomena of the heart by measuring components of magnetocardiogram(MCG) using 61 channel superconducting quantum interference device(SQUD) system. We have analyzed the possibility and characteristics of MCG parameters for diagnosis of ischemic heart disease. A technique for automatic analysis of MCG signals in time domain was developed. The methods for detecting the position, the interval, the amplitude ratio, and the direction of single current dipole were examined in the MCG wave. The position and interval parameters were obtained by calculating the gradients of a envelope curve which could be formed by the difference between the maximum and minimum envelope of multi-channel MCG signals. We show some differences of the frequency contour map between the normal MCG and the abnormal (ischemic heart disease) MCG. The direction of single current dipole can be defined by rotating the magnetic field according to Biot-Savart's law at each point of MCG signals. In this study, we have examined the direction of single current dipole from searching for the centroids of positive and negative magnetic fields. The amplitude ratio parameters for measuring 57 deviation consisted of A$_{T}$/A$_{R}$ and other ratios. and We developed a new analysis method, which is based on the frequency contour map of electromagnetic field. Using theses parameters, we founded significant differences between normal subjects and ischemic patients in some parameters.

• Korean Journal of Acupuncture
• /
• v.26 no.4
• /
• pp.13-22
• /
• 2009

Objectives : Informations on pulse diagnosis in literature are based on diagnosing pulse waveforms on supine posture. However, today's pulse waveforms are measured on various postures for the convenience of patients or doctors. For objective measurement, the effect of posture on the pulse waveforms should be considered. The objective of this study was to find posture-related changes in the radial pulse waveforms. Methods : We used an instrument, DMP-3000(DAEYOMEDI Co., Ansan, Korea), measuring radial pulse waveforms noninvasively by tonometric method. 25 male subjects participated in the trial. Before measuring radial pulse waveforms subjects had rest for 5 min. The pulse waveforms were measured on the left wrist. Each subject underwent this course on the supine, sitting, and standing posture. We analyzed pulse waveforms with Height-parameters, Time-parameters, Energy, and Elastic rate. Results : Height-parameters(h1~h5) on the supine posture were bigger than those on the sitting and standing posture. In case of Time-parameters, the parameters making up systolic time decrease in order of on standing, sitting, and supine position. However, systolic time and diastolic time didn't have any changes. Energy of pulse was the biggest on supine posture and Elastic rate on standing posture. Conclusions : In this study we found that posture changes affect radial pulse waveforms. For quantification of the changes, more trials should be done. After analyzing much data we might apply parameters of pulse waveforms changed by posture. Also, we might diagnose special disease with properties of pulse waveforms by posture.

• Fashion & Textile Research Journal
• /
• v.19 no.4
• /
• pp.493-503
• /
• 2017

This study investigated water vapor permeability of the 73 breathable fabrics for sports-wear according to the materials, finishing methods and fabric structural parameters. The water vapor permeability by KS K 0594 method of PET breathable fabric was superior than that of nylon one, in addition, water vapor permeability of coated or laminated breathable fabrics were higher than those of hot melt or dot laminated fabrics. The water vapor permeability of breathable fabric was dependent on the thickness, weight and density, which was consistent with measuring method. However, water vapor permeability according to materials and finishing method showed different results according to measuring method. The correlation coefficient of WVP of PET breathable fabrics between ISO and KS K measuring methods was -0.83 and the correlation coefficient of WVP of coated breathable fabrics was -0.72 and -0.71 for KS K and ASTM and -0.72 for KS K and ISO in hot melt laminated breathable fabrics. According to regression analysis, WVP of PET breathable fabric by both KSK and ISO measuring methods was highly dependent upon on the density and weight. In addition, WVP of hot melt laminated breathable fabric was highly dependent upon thickness, weight and density. Therefore, relevant measuring method for WVP of breathable fabrics has to be adopted to measure precise breathability.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.29B no.2
• /
• pp.27-39
• /
• 1992

3 Dimensional measurement system using camera and laser slit-ray is studied. Precise calibration technique in this system is suggested. Calibration is accomplished with calibration die, calibration block and robot. For obtaining calibration parameters, the equations are solved using least square error method from a great many calibration points to reduce measuring error. Continuous measurement is possible for the object which is larger than one frame of camera. The efficiency and usability are proved by applying to the tire profile measuring system which measures tire profile using robot and this system.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2008.04a
• /
• pp.391-393
• /
• 2008

• Proceedings of the KIEE Conference
• /
• 1999.07f
• /
• pp.2553-2555
• /
• 1999

The paper contains design formulas and an execution algorithm for calculation of distributed parameters as well as wave and impedance parameters of a uniform transmission line using data of the line input impedance measurements by the OPEN-SHORT method. In difference from published before works on the OPEN-SHORT method application for line parameters determination, in which the lines with small losses are considered /1-3/, the obtained formulas allow to calculate parameters of transmission lines with arbitrary losses. It opens new possibilities of the OPEN-SHORT method utilization for development and application of the probe - type lossy dielectric media parameters meters based on transmission lines, including probe-type moisture material meters.