• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.560-574
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• 2016

This paper presents a novel method for power system harmonic estimation based on the Park transform. The proposed method firstly extends the signal to a group of three-phase signals in a-b-c coordinate. Then, a linear fitting based method is adopted to estimate the fundamental frequency. Afterwards, the Park transform is utilized to convert the three-phase signals from a-b-c coordinate to d-q-0 coordinate. Finally, the amplitude and phase of a harmonic component of interest can be calculated using the d-axis and q-axis components obtained. Simulation studies have been conducted using matrix laboratory (MATLAB) and power system computer aided design/electromagnetic transients including direct current (PSCAD/EMTDC). Simulation studies in MATLAB have considered three scenarios, i.e., no-frequency-deviation scenario, frequency-deviation scenario and the scenario in the presence of inter-harminics. The results have demonstrated that the proposed method achieves very high accuracy in frequency, phase and amplitude estimation under noisy conditions, and suffers little influence of the inter-harmonics. Moreover, comparison studies have proved that the proposed method is superior to FFT and Interpolated FFT with the Hanning Window (IpFFTHW). Finally, a popular case in PSCAD/EMTDC has been employed to further verify the effectiveness of the proposed method.

• Journal of IKEEE
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• v.19 no.3
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• pp.335-341
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• 2015

Recently a demand for high precision absolute position transducer is increasing in order to control thickness in steel industry. LVDT (linear variable differential transformer) is widely used to measure the absolute position in the linearly moving cylinder under poor factory environment. In this paper we implement the three phase LVDT with a high resolution of one micron and L/D (LVDT to digital) converter. First we designed U, V, and W three phase signaling using FPGA. Second a pulse output algorithm is designed for position information with A and B phase waveforms. Finally the performance is compared with previous sensors. Experiments show that the linearity deviation error is 0.009788 [mm] and the average sinusoidal THD is 0.0751%, which means 2.2% and 33% more improved result than the previous sensors respectively.

• Fashion & Textile Research Journal
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• v.12 no.4
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• pp.467-476
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• 2010

The purpose of this study was to develop a plausible methodology based on experimental data how to set up darts and split lines on 3D parametric body dressed with tight-fit garment. The results were as following: Through the process of making convex hull, the concave parts were straightened to make a convex hull, especially in the center part of bust, under breast part and scapular part. To figure out the optimum positions of darts and split lines, the inflection points of curve ratio were searched along the horizontal polylines of waist and bust. This procedures produced reliable results with low deviation. Using Rapidform, CATIA and Unigraphics, six patches of bodice patterns were drawn and aligned. Paired t-test results showed the outline and area between 3D surface and 2D were not significantly different, meaning this method could be adaptable when flattening 3D surfaces. The amount of waist dart measured on the pattern showed that the highest portion was allocated on 2nd dart(back), followed by 1st dart(back), 1st dart(front), 2nd dart(front)/side dart, and center back dart. A series of findings suggested that curve ration inflection point could be used as a guide to set up darts and split line on 3D parametric model with low deviation.

• Journal of Sericultural and Entomological Science
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• v.3
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• pp.61-67
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• 1963

This report is prepared to find how the filament of cocoon bave size deviation relates with the raw silk made by them which are intensively cultured in this country. Three recommended hybrid varieties and two varieties under working at Suwon Sericultural Experiment Station were selected as specimens. The cocoons were reeled as an individual filament of every fifty meters long skein with a wrap reel to weigh the denier and to investigate the relationship of the above statement so that it may be used for the quality estimation before processing it into raw silk. The conclusions obtained are as follows. (1) The variation of Pk${\times}$Sn was found as best cocoon for 21 denier raw silk use, but the number of cocoon to make the denier has to be eight which might cause more labor cost. (2) Baektoo-Kumkang and Myohiang-Chongchon were found as economical varieties for 21 denier use. (3) Seulak-Soyang is a proper variety for the use of 14 or 28 denier silk use. (4) Myohiang-Chongchon did not confirm a good property from the aspect of denier deviation. (5) It was found that there was a fairly strong corelationship between the mean cocoon bave size deviation as indicated by Ono's report. (6) Three graphs were prepared to estimate the cocoon quality before processing into various sizes of raw silk using the mean cocoon bave size and the raw silk size to be prepared. (7) Mean time, the graph which is able to estimate the expectable grade of the raw silk size deviation was designed for the practical use. (8) The expectable grade of the varieties used in this report were found as following data. Notice (A......cocoon number to make raw silk (B......total cocoon bave size deviation (C......expectable silk grade (9) The result of the work concerning the expectable denier deviation on 21 denier silk was the same with the statistical actual testing result as 1.25 D while the distribution showed farther necessity of improvement in technically.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.523-532
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• 2008

In this paper, we proposed a U-shaped RFID tag antenna with isotropic radiation characteristic for the stable operation of RFID system. The proposed antenna is composed of a U-shaped half wavelength dipole and a rectangular-shaped feed. In order to have good impedance matching with a tag chip, the commercial tag chip is attached to the lower center of the feed. A gain deviation characteristic of the U-shaped tag antenna can be further improved by inserting a rectangular slit in the lower center of the U-shaped antenna body. On the condition of VSWR<2, the tag antennas of two structures satisfy the Korea UHF RFID bandwidth and showed the gain deviation of less than 1.63 dB and 0.74 dB for without slit and with slit, respectively. On the condition of VSWR<5.8, the U-shaped tag antenna showed the gain deviation of less than 3.8 dB and 1.2 dB for without slit and with slit, respectively.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.653-662
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• 2011

As technology in 3D industry has rapidly advanced, a lot of studies primarily focusing on visual function and cognition have become vigorous. However, studies on effect of 3D visual fatigue on autonomic nervous system have not less been conducted. Thus, this study was to identify and determine the effect that might have a negative influence on sympathetic nervous system, parasympathetic nervous system, and cardiovascular system. Fifteen undergraduates (female: 9, mean age: $22.53{\pm}2.55$) participated and were sat on a comfortable chair, viewing a 3D content during about 1 hour. Cardiac responses like SDNN(standard deviation of RR intervals), RMS-SD(root mean squared successive difference), and HF/LF ratios extracted from the measured PPG(Photo-PlethysmoGram) before viewing 3D were compared to those after viewing 3D. The results showed that after subjects watched the 3D, responses in sympathetic nervous system and parasympathetic nervous system were activated and deactivated, respectively relative to those before watching the 3D. The results showed that HF/LF ratio, Ln(LF), and Ln(HF) after viewing 3D were significantly reduced relative to those before viewing 3D. No significant effects were observed in SDNN and RMS-SD. Results obtained in this study showed that visual fatigue induced by watching 3D adversely influenced autonomic nervous system, and thereby reduced heart rate variability causing sympathetic nervous acceleration.

• Journal of Photoscience
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• v.4 no.3
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• pp.105-112
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• 1997

The fluorescence quenching of 2, 5-di-(5-tert-butyl-2-benzoxazolyl)-thiophene (BBOT) by aniline in five different solvents namely heptane, hexane, cyclohexane, dioxane and acetonitrile has been carried out at room temperature with a view to understand the quenching mechanisms. The experimental results show positive deviation in the Stern-Volmer plots in all the solvents. In order to interpret these results we have invoked the Ground state complex and sphere of action static quenching models. Using these models various rate parameters have been determined. The magnitudes of these parameters suggest that sphere of action static quenching model agrees well with the experimental results. Hence this positive deviation is attributed to the static and dynamic quenching. Further, with the use of Finite Sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R$^1$ and mutual diffusion coefficient D. Finally an attempt has been made to correlate the values of R$^1$ and D with the values of the encounter distance R and the mutual diffusion coefficient D determined using the Edward's empirical relation and Stokes-Einstein relation.

• The Research Journal of the Costume Culture
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• v.16 no.3
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• pp.502-517
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• 2008

The purpose of the study lies in the measurements of breast shapes and upper body types for the women in their 40's, with the use of 3D measurement system, and in the presentation of brassiere patterns fit for their body types. As for the study method, 3D human body types were analyzed with RapidForm 2006, and the upper-body types and breast shapes were statistically classified through technical statistics analysis, cluster analysis, t-test, variance analysis, and cross analysis. The wearing tests went through the comparison of the brassieres of three makers in the market and the experiment brassieres(first and second) and then the evaluations were made by the subjects, the outer appearance assessment by experts, and 3D measurements. The findings of the study indicated that the evaluation of experiment brassieres was excellent in every item, and he significant difference was found out particularly in the items of pressure, rear center, front center, breast underneath, adequate level by wing, and adequate level by armhole. According to the results of 3D evaluation, experiment brassieres had a highest point in fitness with no physical pressure at the wing part and no overall deviation at the cup art. The pattern comparison showed the differences in the parts of total cup angle, cup circumference length, lower cup height, wing length, and wing angle.

• The Research Journal of the Costume Culture
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• v.16 no.3
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• pp.488-501
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• 2008

The purpose of this study presents bra pattern using the 3D measurements of the upper body subject to women in their 30's. Brassieres available in the market are mostly designed for straight body shape and many women seem to have experienced bearing discomfort in a great extent as they grow older. Brassieres should be designed to cover diverse body types and the accurate measurement of body type and breast shape is needed to accomplish that. As for the study method, 3D human body types were analyzed with RapidForm 2006, and the upper-body types and breast shapes were statistically classified through technical statistics analysis, cluster analysis, t-test, variance analysis, and cross analysis. The wearing tests went through the comparison of the brassieres of three makers in the market and the experiment brassieres(first and second) and then the evaluations were made by the subjects, the outer appearance assessment by experts, and 3D measurements. The results of this study showed that the evaluation of experiment brassieres was excellent in every item, and the significant difference was found out particularly in the items of pressure, rear center, front center, breast underneath, adequate level by wing, and adequate level by armhole. According to the results of 3D evaluation, experiment brassieres had a highest point in fitness with no physical pressure at the wing part and no overall deviation at the cup part.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.1
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• pp.23-31
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• 1986

Meteorological Measurement was performed for evaluation of the horizontal vertical standard deviation $(\sigma_y, \sigma_z)$, surface roughness length and stmospheric stability during the period of March to October 1985 The major results are as follows; 1) The average value of surface roughness length was 144cm at NEPI. 2) In frequency distribution of atmospheric stability, neutral state (D class) was dominent in Seoul (29%) and Pusan (30%). Unstable states (A. B. C. class) were 26% in Seoul and 24% in Pusan. Also, stable states (D. E. F class) were 74% in Seoul and 76% in Pusan. 3) Standard deviations of horizontal ad vertical direction were evaluated as a function of downwind distance and atmospheric stability at NEPI, Jamsil and Pujeondong (Pusan). Standard deviation of horizontal direction was largest at NEPI among 3 areas because of mechanical turbulence resulting from difference of surface roughness length.