• Progress in Medical Physics
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• v.12 no.2
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• pp.133-140
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• 2001

The dose calculations for blocked fields were studied. The shielding block correction factors(K$_{b}$) as a function of collimator and blocked field size(r$_{c}$ and r$_{b}$) were measured. A simplified $K_{b}$ as a function of $A_{r}$ (the A/P ratio of r$_{b}$ to r$_{c}$) was determined by measured data and a fitting function for $K_{b}$ was obtained. We found that the corrections of $K_{b}$ for blocked fields in MU(monitor units) calculations need not take into account in common case of $A_{r}$ \ulcorner1 but the errors will be 3.5% in particular case such as $A_{r}$ = 0.5. These results imply that the shielding block correction for blocked fields in clinical dose calculations must be considered.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.317-322
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• 2003

Cytogenetic and hematological analysis was performed in peripheral blood from the Korean native goat bred in the nuclear power plant (Wolsong and Uljin) and control area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from goat was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dose of radiation was calculated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 to 4 Gy from the goat lymphocytes with in vitro irradiation. MN rates in goats from the Wolsong and Uljin nuclear power plant, and control area were 9.60/1000, 6.83/1000 and 9.88/1000, respectively. There were no significant differences in MN frequencies and hematological values in goats between nuclear power plant and control area. High level of platelet in the goat from Uljin nuclear power plant was observed, which seemed to be related to the goat management.

• The Research Journal of the Costume Culture
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• v.17 no.2
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• pp.203-215
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• 2009

The purpose of this study was to investigate current garment sizes of women's formal jackets, targeting plus-size women in online shopping malls, and to identify effective size information involved in online apparel purchase behaviors to overcome the short comings of current garment sizes from the perspectives of consumers. Basic 88 size formal jackets from the seven companies found on the 22 websites were collected and analyzed. The data were collected from March to October 2007, and analyzed using SPSS 14.0. The results were summarized as follows. First, there was no website using standard garment size labeling with 'bust-hip-height' set up by KS K 0051 among the 22 websites. Instead, all 22 websites used garment size labeling with figures such as 88, 99, 100, 110, and 120 or with letters such as L, XL, and XXL. The websites presented no body size, but listed garment size. Furthermore, the size information was presented differently, ranging from three items of bust circumference, upper arm length, and jacket length to six items of shoulder width, bust circumference, waist circumference, sleeve width, sleeve length, and jacket length. In addition, no website presented basic information for hip circumference, despite the jacket length covering the hips. Second, a total of 85.7% the websites listed bust circumferences in 88 garment sizes collected as 100cm. Shoulder widths were presented as 39cm or 37cm. Sleeve circumferences were addressed the same, 36cm, in all websites. Third, comparing the differences between guidance sizes and measurement sizes, only 28.5% of the web sites posted guidance sizes of shoulder widths the same as those of the measurement sizes. All web sites presented guidance sizes of bust circumstances as 1 to 5cm smaller than those of the measurement sizes.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.221-230
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• 2010

The purpose of this study was to analyze biomechanical factors of trail running shoes applied to korean shoe-lasts. 10 healthy male subjects with an average age of 37.2 years(SD=8.28), weight of 69.6 kg(SD=10.56) and a height of 171 cm(SD=4.93) were recruited for this study. Ten males walked on a treadmill wearing four different shoes. Foot pressure data was collected using a Pedar-X mobile system(Novel Gmbh., Germany) operating at the 1000 Hz. Surface EMG signals for tibialis anterior, gastrocnemius, vastus lateralis and biceps femoris were acquired at 1000 Hz using Noraxon TeleMyo DTS system(Noraxon Inc., USA). Foot pressure and leg muscle fatigue were measured and calculated during walking. The results are as follows: After walking 60 minutes, Type A showed a lower MPF. MPF values were significantly different from each muscle(p<.05). Therefore, Type A shoe might decrease muscle fatigue in the legs while walking. In addition, Type It showed that Type A shoe has the highest contact area and the lowest maximum pressure. As a result of the analysis, Trail running shoes will use a new design to reduce muscle fatigue and are expected to increase comfort and fitting.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.1-14
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• 2005

In this study, a Long Path Differential Optical Absorption Spectroscopy system (K-JIST LP-DOAS) has been used to simultaneously measure atmospheric monoaromatic hydrocarbons and other trace compounds. The validity of the K-JIST LP-DOAS for measuring atmospheric monoaromatic hydrocarbons was tested during a field campaign between 12 February and 14 March 2003 at an urban site in Seoul, Korea through inter-comparative measurements against a collocated on-line Gas Chromatography (GC) system. The concentrations of benzene, toluene, p-xylene, and m-xylene were measured with the K-JIST LP-DOAS system in the UV region (239～302 nm) over a 740 m beam path. For the other trace compounds, a longer spectral range (299～362 nm) was used. In order to remove the interference of atmospheric abundant species (such as oxygen, sulfur dioxide and ozone), two oxygen optical density spectra obtained at two pathlengths, 697 and 1133m, and reference spectra of sulfur dioxide and ozone were incorporated in the fitting procedure. The mean concentrations measured by our LP-DOAS during the measurement period were 0.77 ($\pm$0.38) ppbv for benzene, 3.68 ($\pm$1.90) ppbv for toluene, 0.41 ($\pm$0.19) ppbv for p-xylene, 0.54 ($\pm$0.24) ppbv for m-xylene. The concentration data of benzene, toluene, p-xylene and m-xylene obtained by our LP-DOAS were found to be in relatively good correlations with those of the online GC system. Pearson's coefficients in the observed concentrations between LP-DOAS and on-line GC were 0.84 for benzene, 0.83 for toluene and 0.65 for m,p-xylene. This study suggests that the LP-DOAS system can be used to provide reliable information on both the mixing ratios and temporal distribution characteristics of monoaromatic hydrocarbons in the urban air.

• Journal of Korean Society of Forest Science
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• v.88 no.3
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• pp.320-326
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• 1999

In this study, 15 survival functions in integral and difference forms for forest plantation were derived based on assumptions for the number of surviving trees and the differential forms of the mortality rate model. Then, performance of the models was evaluated by fitting to remeasurement data of unthinned white pine(Pinus strobes) forest plantation. As a result, three equations associated with a power function of age, $t^{\beta}$, are somewhat more suitable for describing the effect of self-thinning over time. On the other hand, a general survival function for Japanese larch(Larix leptolepts) forest plantation was derived in order to exam the effect of site quality on self-thinning procedures. The results indicate that the $N_{min}$ is negatively correlated with site index and, even though the same initial stand density was assumed, the survival function curves differ in shapes associated with site index values.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.12
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• pp.609-619
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• 2015

A preprocessing scheme utilizing multi-division of the ROI (region of interest) in a chemiluminescence image during inversion is proposed. The resulting inverted image shows the flame's structure, which can be useful for studying combustion instability. The flame structure is often quantitatively visualized with PLIF (planar laser-induced fluorescence) images as well. The chemiluminescence image, which is a line-integral of the flame, needs to be preprocessed before inversion, mainly due to the inherent noise and the assumption of axisymmetry during the inversion. The feasibility of the multi-division preprocessing technique has been tested with experimentally-obtained OH PLIF and $OH^*$ chemiluminescence images of jet and swirl-stabilized flames burning substitute natural gas (SNG). It turns out that the technique outperforms two conventional methods, specifically, the technique without preprocessing and the one with uni-division, reconstructing the SNG flame structures much better than its two counterparts when compared using corresponding OH PLIF images. The characteristics of the optimum degree of polynomials to be applied for curve-fitting of the flame region data for the multi-division method involving two flames has also been investigated.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.4
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• pp.1-8
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• 2009

Image compression schemes, such as JPEG and JPEG2000, degrade the Quality of a reconstructed image due to their lossy characteristics. Accordingly, this paper investigates the relationship between the compression ratio and the gamut variation for a reconstructed image using JPEG and JPEG2000. To analyze the relationship between compression ratio and gamut variation, i.e. the hue and chroma shift in the uniform color space, eighteen color samples from the Macbeth ColorChecker are initially used. Based on the color shift phenomenon for the color samples, twelve natural color images, classified into two groups depending on four color attributes, are also used to investigate the relationship between the level of compression and the variation in the gamut area. As a results, through the experiments, least square method is applied to obtain the fitting curves as an equation minimizing the error between the real data and its corresponding approximated values.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.397-403
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• 2015

In this paper, a method of ISAR geometric calibration is represented by using impulse-radio UWB radar. The ir-UWB is good for using a signal processing in time domain, so, it does not occur a multi-path or coupling problem. If a signal that between antennas and target is assumed a plane wave, a center of rotation in ISAR geometry model can be estimated by using point target. Before image is reconstructed with sinogram, the center of rotation can be calculated by using least square fitting. This method can be obtained a more contrast image, and a maximum value of entropy of image. The method, that estimates a center of rotation in received data, will be used a initial setup of instruments or a periodic compensation to reconstruct image. It would be useful in medical, security and surveillance imaging equipments that have a fixed geometry.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.36.2-37
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• 2016

We study the long-term radio variability of 43 radio bright AGNs by exploiting the data base of the University of Michigan Radio Astronomy Observatory (UMRAO) monitoring program. The UMRAO database provides high quality lightcurves spanning 25 - 32 years in time at three observing frequencies, 4.8, 8, and 14.5 GHz. We model the periodograms (temporal power spectra) of the observed lightcurves as simple power-law noise (red noise, spectral power $P(f){\propto}f^{-{\beta}}$ using Monte Carlo simulations, taking into account windowing effects (red-noise leak, aliasing). The power spectra of 39 (out of 43) sources are in good agreement with the models, yielding a range in power spectral index (${\beta}$) from ${\approx}1$ to ${\approx}3$. We find a strong anti-correlation between ${\beta}$ and the fractal dimension of the lightcurves, which provides an independent check of the quality of our modelling of power spectra. We fit a Gaussian function to each flare in a given lightcurve to obtain the flare duration. We discover a correlation between ${\beta}$ and the median duration of the flares. We use the derivative of a lightcurve to obtain a characteristic variability timescale which does not depend on the assumed functional form of the flares, incomplete fitting, and so on. We find that, once the effects of relativistic Doppler boosting on the observed timescales are corrected, the variability timescales of our sources are proportional to the black hole mass to the power of ${\alpha}=1.70{\pm}0.49$. We see an indication for AGNs in different regimes of accretion rate, flat spectrum radio quasars and BL Lac objects, having different scaling relations with ${\alpha}{\approx}1$ and ${\approx}2$, respectively. We find that modelling the periodograms of four of our sources requires the assumption of broken powerlaw spectra. From simulating lightcurves as superpositions of exponential flares we conclude that strong overlap of flares leads to featureless simple power-law periodograms of AGNs at radio wavelengths in most cases (The paper is about to be submitted to ApJ).