• Korean Journal of Remote Sensing
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• v.18 no.5
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• pp.255-261
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• 2002

Strong and coherent radar backscattering signals are observed over oyster sea farms that consist of artificial structures installed on the bottom. We successfully obtained 21 coherent interferograms from 11 JERS-1 SAR data sets even though orbital baselines (up to 2 km) or temporal baselines (up to 1 year) were relatively large. The coherent phases preserved in the sea farms are probably formed by double bouncing from sea surface and the sea farming structures, and consequently they are correlated with tide height (or instantaneous sea level). Phase unwrapping is required to restore the absolute sea level. We show that radar backscattering intensity is roughly correlated with the sea surface height, and utilize the fact to determine the wrapping counts. While the SAR image intensity gives a rough range of absolute sea level, the interferometric phases provide the detailed relative height variations within a limit of $2{\pi}$ (or 15.3 cm) with respect to the sea level at the moment of the master data acquisition. A combined estimation results in an instantaneous sea level. The radar measurements were verified using tide gauge records, and the results yielded a correlation coefficient of 0.96 with an r.m.s. error of 6.0 cm. The results demonstrate that radar interferometry is a promising approach to sea level measurement in the near coastal regions.

• Current Optics and Photonics
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• v.2 no.2
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• pp.179-184
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• 2018

Terahertz (THz) wave generation by periodically poled $BaTiO_3$ (PPBT) with a quasi-phase-matching (QPM) scheme based on cascaded difference-frequency generation (DFG) is theoretically analyzed. The cascaded DFG processes comprise cascaded Stokes and anti-Stokes processes. The calculated results indicate that the cascaded Stokes processes are stronger than the cascaded anti-Stokes processes. Compared to a noncascaded Stokes process, THz intensities from $20^{th}$-order cascaded Stokes processes increase by a factor of 30. THz waves with a maximum intensity of $0.37MW/mm^2$ can be generated by $20^{th}$-order cascaded DFG processes when the optical intensity is $10MW/mm^2$, corresponding to a quantum conversion efficiency of 1033%. The high quantum conversion efficiency of 1033% exceeds the Manley-Rowe limit, which indicates that PPBT is an excellent crystal for THz wave generation via cascaded DFG.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.396-405
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• 2021

In surgery to remove pancreatic cancer, it is important to figure out the shape of a patient's pancreas. However, previous studies have a limit to detect a pancreas automatically in abdominal CT images, because the pancreas varies in shape, size and location by patient. Therefore, in this paper, we propose a method of learning various shapes of pancreas according to the patients and adjacent slices using Faster R-CNN based on Inception V2, and automatically detecting the pancreas from abdominal CT images. Model training and testing were performed using the NIH Pancreas-CT Dataset, and intensity normalization was applied to all data to improve pancreatic detection accuracy. Additionally, according to the shape of the pancreas, the test dataset was classified into top, middle, and bottom slices to evaluate the model's performance on each data. The results show that the top data's mAP@.50IoU achieved 91.7% and the bottom data's mAP@.50IoU achieved 95.4%, and the highest performance was the middle data's mAP@.50IoU, 98.5%. Thus, we have confirmed that the model can accurately detect the pancreas in CT images.

• Applied Chemistry
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• v.15 no.1
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• pp.25-28
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• 2011

A highly sensitive spectrofluorimetric method was developed for the determination of levodopa based on the formation of a ternary complex with Eu³⁺ in the presence of ethylenediaminetetraacetic acid. It was found that this complex manifests intense fluorescence at 591 and 613 nm with excitation at 372 nm and maximum intensity was obtained at 613 nm. Under the optimum conditions, the enhanced fluorescence intensity was proportional to the concentration of levodopa over the range of 3×10^-9-2.5×10^-7 mol L^-1 with limit of detection (LOD) of 4.37×10^-10 mol L^-1. The method offers higher sensitivity and selectivity which could be effectively applied for the determination of levodopa in pharmaceutical and biological samples.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.149-162
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• 2005

The aim of this study was to measure the suprathreshold taste intensity for sucrose, NaCl, citric acid, and quinine HCl in Korean young people using a whole-mouth, sip-and-spit procedure, employing the method of magnitude matching. The results were analysed in terms of sex, taste preference, and smoker or nonsmoker. One hundred twenty three subjects (61 male and 62 female, mean age of 25.2$\pm$2.1 years) were included for the study. Subjects were instructed to give nonmodulus magnitude estimates to the intensities of five concentrations each of sucrose, NaCl, citric acid, and quinine HCl; distilled water; 6 loudness levels of a 1,000-Hz tone, using the same 9-point intensity scale. Each of the 21 taste stimuli and 6 auditory stimuli are presented in random order twice. The auditory function is used to assess the absolute intensity function of the subject's taste system. The results were as follows; 1. The perceived taste intensity for sucrose, NaCl, citric acid, and quinine HCl increased progressively as the concentrations of taste solutions were increased. Most of the subjects are standing within the zone of mean value $\pm$1standard deviation in their total perceived intensity score, and nobody is outside the limit of mean value - 2standard deviation. 2. There were not significant difference in total perceived intensities for sucrose, NaCl, citric acid, and quinine HCl between males and females. 3. There were not significant difference in total perceived intensities for sucrose, NaCl, citric acid, and quinine HCl according to the difference in taste preference. 4. There were not significant difference in total perceived intensities for sucrose, NaCl, citric acid, and quinine HCl between smokers and non-smokers in males.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.643-654
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• 2018

In order to understand and manage traffic flows in urban areas in the past, a variety of traffic engineering theoretical indicators such as intersection lag and highway speed have been applied. However, these theories and indicators have been developed under the constraints of traffic engineering research before the construction of intelligent transportation system. Since the ATIS system currently exists, it is necessary to introduce a separate traffic engineering technology that utilizes the data. In this paper, it is aimed to confirm whether it is applicable to intermittent flow (approach road, intersection, control group, main road axis) by using 'congestion intensity' which is already used in traffic engineering field. The results of this study are as follows: (1) The traffic signal improvement effect of urban road access road, intersection road, control group, Two verification studies were performed to verify the derived congestion intensity index. (1) verification of congestion intensity threshold value analysis and (2) crossing improvement using the congestion intensity. Through verification, it was confirmed that it is possible to apply the congestion intensity in the inter - city intermittent flow using the 5 - minute unit speed data so as to be able to escape from the existing traffic signal operation management which is past passive and manpower limit.

• Journal of Korean Physical Therapy Science
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• v.15 no.1
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• pp.1-9
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• 2008

Background and Purpose : This study serves the purpose to present the effective way on back pain therapy for women during their pregnancy by comparing and analyzing the effects influencing on pain index, limits on daily life, and diminution of lumbar curve, when having treated for 6 weeks, dividing into therapy group, applied by decompression therapy on spine without unnecessary effects on the pregnant women and their fetus and the existent general physiotherapy group, applied on diminution of their back pain. Subject & methods : We made impregnate women of 30(25${\sim}$34years), as the subject of this study, who understood, and agreed with, this study, among pregnant women who were diagnosed as back pain. Pain intensity, limit index on daily life, and lumbar curve test, prior to experiment was implemented as paired t－test, comparison of the difference of average by each group before and after experiment was analysed as independent t－test, and statistical examination level was set up as 0.05. Results : The difference of average of pain and limit on daily life between the group, SDTG(spinal decompression therapy group), and the group, GPTG(general physical therapy group), before and after experiment was diminished as much as 44.4% and 16.79% each after completed 6 weeks' experiment, limit on daily life in both groups showed as much as 37.2% and 21.5% each, in the end, they statistically showed conspicuous difference(p<.05). Comparison of lumbar curves between both groups, SDTG and GPTG, before and after experiment, were diminished from -23.13${\pm}$4.85 to -15.66${\pm}$3.71, and there was no remarkable difference(p<.05). Conclusion : As, in this study, decompression therapy is more effective than general physical therapy with pregnancy low back pain in pain, limitation of daily life, lumbar curve.

• Earthquakes and Structures
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• v.10 no.2
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• pp.367-388
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• 2016

Eccentrically braced frames (EBFs) represent an attractive lateral load resisting steel system to be used in areas of high seismicity. In order to assess the likely damage for a given intensity of ground shaking, fragility functions can be used to identify the probability of exceeding a certain damage limit-state, given a certain response of a structure. This paper focuses on developing a set of fragility functions for EBF structures, considering that damage can be directly linked to the interstorey drift demand at each storey. This is done by performing a Monte Carlo Simulation of an analytical expression for the drift capacity of an EBF, where each term of the expression relies on either experimental testing results or mechanics-based reasoning. The analysis provides a set of fragility functions that can be used for three damage limit-states: concrete slab repair, damage requiring heat straightening of the link and damage requiring link replacement. Depending on the level of detail known about the EBF structure, in terms of its link section size, link length and storey number within a structure, the resulting fragility function can be refined and its associated dispersion reduced. This is done by using an analytical expression to estimate the median value of interstorey drift, which can be used in conjunction with an informed assumption of dispersion, or alternatively by using a MATLAB based tool that calculates the median and dispersion for each damage limit-state for a given set of user specified inputs about the EBF. However, a set of general fragility functions is also provided to enable quick assessment of the seismic performance of EBF structures at a regional scale.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.857-864
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• 2012

A linear stability analysis of a diffusion flame with radiation heat loss is performed to identify linearly unstable conditions for the Damk$\ddot{o}$hler number and radiation intensity. We adopt a counterflow diffusion flame with unity Lewis number as a model. Near the kinetic limit extinction regime, the growth rates of disturbances always have real eigenvalues, and a neutral stability condition perfectly falls into the quasi-steady extinction. However, near the radiative limit extinction regime, the eigenvalues are complex, which implies pulsating instability. A stable limit cycle occurs when the temperatures of the pulsating flame exceed the maximum temperature of the steady-state flame with real positive eigenvalues. If the instantaneous temperature of the pulsating flame is below the maximum temperature, the flame cannot recover and goes to extinction. The neutral stability curve of the radiation-induced instability is plotted over a broad range of radiation intensities.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.163-169
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• 2017

Objectives: This study was conducted toestimate quartz concentrations and contents in the airborne respirable dust from various industries. Methods: A total of 818 samples were collected from 174 industries. Respirable dust samples were collected using a cyclone equipped with a 37 mm, $5{\mu}m$ pore size PVC filter. The quartz concentrations were identified using the intensity of the absorption peak of quartz at $799cm^{-1}$ by Fourie Transformed Infrared Spectroscopy(FTIR). Results: The respective geometric means for quartz concentrations in the respirable dust were 0.0050, 0.0049, 0.0025, and $0.0019mg/m^3$ in foundries, ceramics, construction, and cement/stone. The geometric mean of quartz contents analyzed by FTIR were respectively 3.43, 1.99, 1.04, and 0.82% for ceramics, foundries, cement/stone, and construction. The rate of exceeding the Korean Occupational Exposure Limit($0.05mg/m^3$) was 2.03%, but rate of exceeding the American Conference of Governmental Industrial Hygienist(ACGIH) Threshold Limit Value($0.025mg/m^3$) was 7.12%. Conclusions: Given that foundries had a higher quartz concentration, there is a need to reduce respirable dust, such as through wet operation. In order to protect the health of workers exposed to mineral dust, it is necessary to actively consider strengthening the Korean Occupational Exposure Limit.