• Environmental Analysis Health and Toxicology
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• v.21 no.1 s.52
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• pp.27-34
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• 2006

Numerous studies reported the significant association between genetic polymorphisms in the vitamin D receptor (VDR) gene and various bone phenotypes such as bone mineral density (BMD) and bone quality, although conflicting results were produced. The objective of this study was to investigate the association between a TaqI RFLP in the VDR gene and calcaneal BMD in Korean vegetarian men, and its interaction with nutrition status as an environmental factor. BUA (broadband ultrasound attenuation), SOS (sound of speed) and stiffness index of the calcaneus were measured using an ultrasound bone densitometer in 266 Korean men (age: $mean{\pm}SD;\;50.9{\pm}12.0$ year), and a TaqI RFLP in the VDR gene analysed by PCR-RFLP method. In total subjects, the distribution of TT, Tt and tt genotypes occurred with frequencies of 90.8%, 8.8% and 0.4%, respectively. There were no significant associations between this polymorphism and osteopenia-osteoporosis or several bone phenotypes in our subjects irrespectively of nutrition status (P>0.05). Therefore, our results suggest that a TaqI RFLP in the vitamin D receptor gene does not contribute to the susceptibility to the calcaneal BMD in Korean men.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.656-659
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• 2017

In this paper, we propose a digital method for transmitting audio signals using LED visible light communication system. In the proposed method, we compare the method for transmitting audio signal in analog signal and the method for transmitting by digital signal. When amplifying the audio sound and transmitting the analog signal using the LED visible light communication, attenuation corresponding to the transmission distance occurs, and there is a disadvantage that it is noisy. In order to overcome this, we propose a method for transmitting digital audio signals. The proposed method has the advantage of reducing the influence of noise, but it turned out that it is affected much by the LED blinking speed. Various methods to overcome this need to be continuously studied.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.833-839
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• 2014

The shooting noise caused by shooting training, which has strength and impacts, is becoming a serious damage to the residents around the shooting range and, consequently, the number of civil appeals against the shooting noise is on the constant increase. For this reason, the military examines the effects of the shooting noise at the stage of design in constructing a shooting range and tries to build a soundproof shooting range to minimize civil appeals. However, the lack of research and data concerning propagation and attenuation, both of which characterize the shooting noise from within a soundproof shooting range, even makes it so difficult to design a soundproof shooting range in constructing it. So this study used an acoustic simulation in a soundproof shooting range to identify acoustic and propagation characteristics within the shooting range and, on this basis, predicted the noise level at an exit of the soundproof shooting range. As a result, if the form and specifications of a soundproof shooting range were decided on at the stage of design, it was possible to use a simulation to design a soundproof shooting range with optimized acoustic performance and, on this basis, to predict a sound pressure level at an exit of the soundproof shooting range. On the basis of these data, it is probably possible to determine the degree of the effects of the shooting noise on the villages around a shooting range and the extent of damage to it and to minimize civil appeals against the shooting noise and resolve the issues of compensation and agreement with ease. This study is expected to provide useful data for designing and constructing a similar soundproof shooting range.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.484-493
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• 2012

Since the 1980s, there have been many research activities devoted to quantitatively characterizing and imaging human tissues based on sound speed, attenuation coefficient, density, nonlinear B/A parameter, etc., but those efforts have not yet reached the stage of commercialization. However, a new imaging technology termed elastography, which was proposed in the early 1980s, has recently been implemented in commercial clinical ultrasound scanners, and is now being used to diagnose prostates, breasts, thyroids, livers, blood vessels, etc., more quantitatively as a complementary adjunct modality to the conventional B-mode imaging. The purpose of this article is to introduce and review various elastographic algorithms for use in quasistatic or static compression type elasticity imaging modes. Most of the algorithms are based on the crosscorrelation or autocorrelation function methods, and the fundamental difference is that the time shift is estimated by changing the lag variable in the former, while it is directly obtained from the phase shift at a fixed lag in the latter.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.103-109
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• 2016

Efficacy of cosmetics has been mainly evaluated by qualitative and quantitative methods based on visual sense, tactile sense and skin structure until now. In this study, we suggested a novel evaluation method for skin status based on sound; measuring and analyzing the rubbing noise generated by applying cosmetics. First, the rubbing noise was measured at a close range by a high-sensitivity microphone in anechoic environment, and the noises were analyzed by 1/3 octave band analysis in frequency-domain. Three conditions, 1) before washing, 2) after washing and 3) after application of cosmetics, were compared. As a result, sound pressure level (SPL) of rubbing noise after washing was larger than that of before washing, and the SPL of rubbing noise after cosmetic application was the smallest. Furthermore, the energy of rubbing noise after application was higher than that of the before and after washing conditions in a low frequency band (lower than 2 kHz region). Conversely, the energy of rubbing noise after application was much lower than the others in a high-frequency band (upper than 2 kHz region). This change of energy distribution was described as a balloon-skin model. High SPL in the low frequency region after the cosmetic applications was due to the increase of "flexibility index", while SPL in the high frequency region significantly decreased because of the attenuation which is related to "softness index". Therefore, we developed two indices based on the spectrum-energy difference for evaluating skin conditions. This proposed method and indices were verified via skin flexibility and roughness measurement using cutometer and primos respectively. These results suggest that acoustic measurement of skin friction noise may be a new skin status evaluation method.

• Tuberculosis and Respiratory Diseases
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• v.52 no.2
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• pp.179-185
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• 2002

A bronchus-associated lymphoid tissue(BALT) lymphoma of the lung is a rare disorder of patients with Sj$\ddot{o}$gren's syndrome. A 49-year-old woman was admitted for an evaluation of exertional dyspnea and general weakness which had persisted for two years. The patient had suffered from dry mouth and dry eyes for five years. The physical examinations showed a coarse breath sound with inspiratory crackles on the whole lung field, particularly on the both basal lungs. The laboratory data disclosed high titers of anti-nuclear antibodies, and anti-SSA (Ro), and anti-SSB (La) antibodies. Chest radiographs demonstrated the presence of bilateral, diffuse, reticulonodular densities in both lungs. Thin-section CT scans showed diffusely distributed mosaic pattern of an inhomogeneous attenuation extending over the entire lung zone. The histological findings from an open-lung biopsy specimen revealed an accumulation of lymphoid cells around the bronchioles and an extension of malignant lymphoma cells from the bronchiolar epithelium toward the alveolar space. Immunohistochemically, the neoplastic cells reacted positively to the CD 20 antigen and were focally positive for the UCHL 1 antigen. The histological diagnosis was consistent with a low grade marginal zone B-cell lymphoma originating in the BALT. Here, we present a case of a histologically proven BALT lymphoma of the lung in a patient with primary Sj$\ddot{o}$gren's Syndrome.

• Journal of radiological science and technology
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• v.31 no.2
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• pp.135-140
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• 2008

Purpose: Fatty liver is one of the most commonly found disease by abdominal ultrasonography. The status of fatty liver is classified into mild, moderate and severe degrees. The study was conducted to investigate the clinical significance of fatty liver using ultrasonography. Materials and method: Test set consisted of 2,185 patients who visited D healthcare center in Daejeon to receive an abdominal ultrasonic test from January to December 2007. Out of the 2185 patients, 524 patients was diagnosed as fatty liver (290 male and 234 female patients). They were divided into three groups, group I for mild degree. II for moderate degree, and III for severe degree, depending on the echo of liver parenchyma, the sound attenuation, and the visibility of intrahepatic blood vessels and diaphragm. Then the correlation of obesity indices, liver function tests and metabolic syndrome was analyzed for males and females separately. Results : As for the degree of fatty liver, 350 cases (66.8%) were classified as group I, 153 cases (29.2%) as group II, and 21 cases (4.1%) as group III. In addition, severe degree of fatty liver was more frequently found in males than in females. The mean ages of three groups for males were 46.1, 44.5, and 39.1, and those for females were 48.8, 50.2, 52.4, respectively. Males with lower mean ages have severely of fatty liver for both males and females. Conclusion: The results in this study show that the classification into three degrees of fatty liver in ultrasonography practice is helpful to treat and observe the progress of fatty liver. In addition, careful examination is required to measure the severity of fatty liver as well as detection of it. A standardized method to classify the degree of fatty liver is also needed for more objective measurement.

• Journal of Environmental Impact Assessment
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• v.26 no.1
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• pp.11-26
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• 2017

Approximate empirical equations obtained by measuring overall noise levels at different distances have been used to evaluate environmental influence of the railway noise though the accurate prediction of noise levels is important. In this paper, a noise prediction model considering the frequency characteristics of noise sources and propagation was suggested to improve the accuracy of noise prediction. The railway noise source was assorted into track, wheel, traction and aerodynamic components and they were characterized with the source strength and speed coefficient at each octave-band frequency. Correction terms for the acoustic roughness and the track/bridge condition were introduced. The sound attenuation from a source to a receiver was calculated taking account of the geometrical divergence, atmospheric absorption, ground effect, diffraction at obstacles and directivity of source by applying ISO 9613-2. For obtaining the source strength and speed coefficients, the results of rolling noise model, numerical analysis and measurements of pass-by noise were analyzed. We compared the predicted and measured noise levels in various vehicles and tracks, and verified the accuracy of the present model. It is found that the present model gives less error than the conventional one, so that it can be applied to make the accurate prediction of railway noise effect and establish its countermeasures efficiently.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.751-758
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• 2015

Noise prediction for HVAC(Heating, Ventilating and Air Conditioning) systems are normally performed by empirical method suggested by NEBB(National Environmental Balancing Bureau, 1994). However, the method is not suitable for large ducts in ships. In this paper, computational analysis methods are used to develop a noise prediction method for the large ducts in ships. To develop regression formula of attenuation of sound pressure level in large ducts, Boundary Element Method(BEM) is used. BEM and Computational Fluid Dynamics(CFD) are applied to the analysis of flow-induced noise in ducts with stiffeners inside. Loud noise above 100 dB can be generated in some cases. Breakout noises of large ducts are also analyzed by using BEM and Finite Element Method(FEM). The acoustic pressure level shows about 10-15dB difference between inside and outside of the duct. Utilizing the results of this study, it is expected that shipyard planners can predict noise of the HVAC system for ships.

• The Journal of the Acoustical Society of Korea
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• v.29 no.4
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• pp.223-228
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• 2010

High-frequency bottom loss measurements for grazing angle of $82^{\circ}$ in frequency range 17-40 kHz were made in Jinhae bay in the southern part of Korea. Observations of bottom loss showed the strong variation as a function of frequency, which were compared to the predicted values using two-layered sediment reflection model. The geoacoustic parameters including sound speed, density and attenuation coefficient for the second sediment layer were predicted from the empirical relations with the mean grain size obtained from sediment core analysis. The geoacoustic parameters for the surficial sediment layer were inverted using Monte Carlo inversion algorithm. A sensitivity study for the geoacoustic parameters showed that the thickness of surficial sediment layer was most sensitive to the variation of the bottom loss.