• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.11a
• /
• pp.121-127
• /
• 2004

Electric ballast is widely used to turn on the fluorescent. Electric ballast measure occurrence of harmonic through the actual measurement and it is simulated by modeling equivalent circuit for harmonic analysis. The purpose of this paper is to give an equivalent circuit modeling methodology for the harmonic currents generated by single-phase personal computer loads to evaluate a commercially available series resonant filter for the harmonic currents compensation based on the IEC std 61000-3-2 and IEEE 519 standards for limiting harmonic distortion.

• Journal of the Optical Society of Korea
• /
• v.20 no.1
• /
• pp.140-149
• /
• 2016

For visual measurement under dynamic scenarios, a zoom lens camera is more flexible than a fixed one. However, the challenges of distortion prediction within the whole focal range limit the widespread application of zoom lens cameras greatly. Thus, a novel sequential distortion correction method for a zoom lens camera is proposed in this study. In this paper, a distortion assessment method without coupling effect is depicted by an elaborated chessboard pattern. Then, the appropriate distortion correction model for a zoom lens camera is derived from the comparisons of some existing models and methods. To gain a rectified image at any zoom settings, a global distortion correction modeling method is developed with bundle adjustment. Based on some selected zoom settings, the optimized quadratic functions of distortion parameters are obtained from the global perspective. Using the proposed method, we can rectify all images from the calibrated zoom lens camera. Experimental results of different zoom lens cameras validate the feasibility and effectiveness of the proposed method.

• Fibers and Polymers
• /
• v.6 no.4
• /
• pp.348-354
• /
• 2005

These days consumers' various demands are accelerating research on apparel manufacturing system including automatic measurement, pattern generation, and clothing simulation. Accordingly, methods of reconstructing human body from point-clouds measured using a three dimensional scanning device are required for apparel CAD system to support these functions. In particular, we present in this study a human body reconstruction method focused on two issues, which are the decision of the number of control point for each sectional curve with error bound and the local knot removal for reducing the unusual concentration of control points. The approximation of sectional curves with error bounds as an approximation criterion leads all sectional curves to their own particular shapes apart from the number of control points. In addition, the application of the local knot removal to construction of human body sectional curves reduces the unusual concentration of control points effectively. The results may be used to produce an apparel CAD system as an automatic pattern generation system and a clothing simulation system through the low level control of NUBS or NURBS.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.2
• /
• pp.35-41
• /
• 2005

Electric ballast is widely used to turn on the fluorescent. Electric ballast measure occurrence of harmonic through the actual measurement and it is simulated by modeling equivalent circuit for harmonic analysis. The purpose of this paper is to give an equivalent circuit modeling methodology for the harmonic currents generated by single-phase loads to evaluate a commercially available series resonant filter for the harmonic currents compensation based on the IEC 61000-3-2 and IEEE Std 519-1992 standards for limiting harmonic distortion.

• Journal of the Korean Solar Energy Society
• /
• v.26 no.1
• /
• pp.65-71
• /
• 2006

This study describes to analyze variation of carbon dioxide gas concentration by experimental and theoretical method according to the using patterns of ventilation system in a model classroom. Concentration of $CO_2$ gas varied by the occupancy and the ventilation systems are operating or not. More than 850 CMH ventilation system can maintain $CO_2$ gas concentration lower than 1,000 ppm along the class time and can be adopted the government guideline. Theoretical modeling of the concentration was performed at well-mixed ideal condition. Delays of concentration decay were shown at each case compared to actual.

• Smart Structures and Systems
• /
• v.1 no.2
• /
• pp.121-140
• /
• 2005

This paper presents a systematic investigation of the effect of sensor location on the data quality and subsequently, on the effectiveness of machine health monitoring. Based on an analysis of the signal propagation process from the defect location to the sensor, numerical simulations using finite element modeling were conducted on a bearing test bed to determine the signal strength at several representative sensor locations. The results showed that placing sensors closely to the machine component being monitored is critical to achieving high signal-to-noise ratio, thus improving the data quality. Using millimeter-sized piezoceramic plates, the obtained results were evaluated experimentally. A comparison with a set of commercial vibration sensors verified the developed structural dynamics-based sensor placement strategy. It further demonstrated that the proposed shock wave-based sensing technique provided an effective alternative to vibration measurement, while requiring less space for sensor installation.

• Tunnel and Underground Space
• /
• v.14 no.4
• /
• pp.295-303
• /
• 2004

For the deep underground excavation site with the geological complexity of soft seam and hard rock, the numerical analysis and in-situ measurement on the behaviors of roadway and surrounding rock according to stepwise excavation of the steep soft seam are carried out. The strata behavior is modeled using elasto-plastic FEM considering the empirical failure criteria of Hoek ＆ Brown and the strain-softening model. Hydraulic pressure capsule, MPBX and tape extensometer are installed around the roadway for the in-situ measurement of rock stress and deformation. Despite the complexity of geology and excavation procedure, the elasto-plastic analysis considering the empirical failure criteria of Hoek ＆ Brown and the strain-softening model shows good agreement with the in-situ measurement. Comparison of numerical modeling with in-situ measurement enables to predict the behaviors of the roadway and to obtain design parameters for the excavation and support at depth.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.16 no.3
• /
• pp.331-337
• /
• 2018

The decommissioning of nuclear power plants is generally executed in five steps, including preparation, decontamination, cutting/demolition, waste disposal and environmental restoration. So, for efficient decommissioning of nuclear power plants, worker safety, effects compared to cost, minimization of waste, possibility of reuse, etc., shall be considered. Worker safety and measurement technology shall be secured to exert optimal efficiency of nuclear power plant decommissioning work, for which accurate measurement technology for systems and devices is necessary. Typical In-Situ methods for decommissioning of nuclear plants are CZT, Gamma Camera and ISOCS. This study used ISOCS, which can be applied during the decommissioning of a nuclear power plant site without collecting representative samples, to take measurements of the S/G Water Chamber. To validate the measurement values, Microshield and the GEANT4 code was used as the actual method were used for modeling, respectively. The comparison showed a difference of $1.0{\times}10^1Bq$, which indicates that it will be possible to reduce errors due to the influence of radiation in the natural environment and the precision of modeling. Based on the research results of this paper, accuracy and reliability of measurement values will be analyzed and the applicability of the direct measurement method during the decommissioning of NPPs will be assessed.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.20 no.2
• /
• pp.91-101
• /
• 2000

Modeling of radiation beam from ultrasonic transducers has been investigated extensively, since it is one of the most important, fundamental issues that have great influence on the accuracy of an ultrasonic measurement model. Here, three popular radiation models, namely the Rayleigh-Sommerfeld integral model, the boundary diffraction wave model and the edge element model, are discussed briefly, and the radiation beam fields from ultrasonic transducers with planar, circular and rectangular cross-sections are calculated using these three models. Then, the accuracy and the time-efficiency of these methods are compared based on the calculation results.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.2
• /
• pp.263-269
• /
• 2012

In order to present that the electromagnetic compatibility standards following the frequency goes up which is based automotive electronics, in this paper, a hybrid/electric vehicle battery which reflects the frequency of the equivalent circuit model is introduced. By using this circuit modeling, the impedance characteristics can be analysed and an analyze of battery one cell is finished. Using this model, each different from the discharging situation, the discharge characteristic curve could be led. Basic theoretical approaches and measuring results through MATLAB and experimental validation of the EIS measurement equipment was used.