• Journal of Korea Water Resources Association
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• v.45 no.3
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• pp.275-290
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• 2012

In this study, we have developed an optimal time distribution model through extraction of peaks over threshold (POT) series. The median values for annual maximum rainfall dataset, which are obtained from the magnetic recording (MMR) and the automatic weather system(AWS) data at Seoul meteorological observatory, were used as the POT criteria. We also suggested the improved methodology for the time distribution of extreme rainfall compared to Huff method, which is widely used for time distributions of design rainfall. The Huff method did not consider changing in the shape of time distribution for each rainfall durations and rainfall criteria as total amount of rainfall for each rainfall events. This study have suggested an extracting methodology for rainfall events in each quartile based on interquartile range (IQR) matrix and selection for the mode quartile storm to determine the ranking cosidering weighting factors on minutely observation data. Finally, the optimal time distribution model in each rainfall duration was derived considering both data size and characteristics of distribution using kernel density function in extracted dimensionless unit rainfall hyetograph.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.933-943
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• 2019

The purpose of this study is to identify determinants for preferred funeral methods depending on socio-economic characteristics. In South Korea, the Act on Funeral Services, Etc. categorizes funeral methods into burial, inurnment, and natural burial. This study empirically analyzes how and what socio-economic characteristics affect choices among these three categories. Data is collected from Social Survey 2017 and funeral facilities in the country. The data to be analyzed is developed in terms of a hierarchy which puts the burial and cremation methods in an upper class and the inurnment and natural burial methods in a lower class. Based on this data, a nested logit model is employed to conduct empirical analysis. The analysis indicates that those characteristics that have a statistically significant influence on preferred methods include gender, age, householder, marriage, satisfaction with life, class awareness, monthly income, housing type, housing tenure type, and living in city area. Each variable's modulus of calculated direct and cross elasticity need to be used to analyze the outcome of a nested logit model. In this study, the modulus of direct and cross elasticity are determined for the significant variables. The calculated direct elasticity is applied to analyze the likelihood of choosing each funeral method when there are changes in the significant variables. When a particular method has been selected, on the other hand, the cross elasticity is utilized to analyze changes to the likelihood of choosing the other methods. One of the most notable results is related to natural burial. In order to meet the demand for natural burial, it is necessary to provide more burial sites and raise awareness of natural burial. This will facilitate the efficient use of national territorial space.

• Journal of the Korea Society for Simulation
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• v.28 no.4
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• pp.57-65
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• 2019

Recently, the Korean military has been drastically reducing its active-duty troops due to rapid demographic changes and the reconciliatory mode between the two Koreas. Under these circumstances, the wartime reserve forces play an important role. In times of war, a successful personal mobilization is critical especially in early combat stage. Previous research has been carried out using insufficient data collected only within the military and there have been limitations on empirical analysis due to changes in the designation methods for personal mobilization. This study analyzes how much of the reserve forces can be filled at the prescribed time by analyzing the transportation route of the reserve forces in wartime by utilizing military-related data and credit card usage data of the reserve forces residing in Yong-in city. The analysis showed that all reserve forces could not be called up within the prescribed time. In particular, Gangwon Province has shown results of less than 70 percent call-ups, and could cause serious weakening of combat capabilities in the early stages of the war. The main reasons could be the difference between the actual residence and the residence address and the excessive time caused by the traffic congestion.

• The Korean Journal of Pain
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• v.33 no.2
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• pp.99-107
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• 2020

Chronic severe pain results in a detrimental effect on the patient's quality of life. Such patients have to take a large number of medications, including opioids, often without satisfactory effect, sometimes leading to medication abuse and the pain worsening. Spinal cord stimulation (SCS) is one of the most effective technologies that, unlike other interventional pain treatment methods, achieves long-term results in patients suffering from chronic neuropathic pain. The first described mode of SCS was a conventional tonic stimulation, but now the novel modalities (high-frequency and burst), techniques (dorsal root ganglia stimulations), and technical development (wireless and implantable pulse generator-free systems) of SCS are becoming more popular. The improvement of SCS systems, their miniaturization, and the appearance of new mechanisms for anchoring electrodes results in a significant reduction in the rate of complications and revision surgeries, and the appearance of new waves of stimulation allows not only to avoid the phenomenon of addiction, but also to improve the long-term results of chronic SCS. The purpose of this review is to describe the current condition of SCS and up-to-date technical advances.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.481-489
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• 2017

The study area,Cheonan Stream, is an urban river that flows through urban areas in close proximity to densely populated areas and multi-use facilities. The natural river improvement project from 2006 to 2015 improved the quality of life of local residents with the improvement of river function, the restoration of the natural ecosystem and the securement of hydrophilic space. A bike way in the constructed waterside space was built focusing on trails. This study suggests improvements appropriate for insufficient bike way function-related regulations. The problems of ramps, river crossing facilities, stairway facilities, safety facilities, signs, road markings, and parking facilities, etc.have arisen in the utilization situation and citizen consciousness survey. As an improvement, it was suggested that 12% or fewer ramps should be improved, a submerged bridge should be installed at 7 places separated by stepping bridges, and signs and road markings according to bike way-related regulations should be installed and bike parking facilities at Cheonan station and Cheonan bus terminal should be expanded. The bike way in the waterfront of ChoenanCheon(river) will increase the accessibility and utilization rate of short-distance transportation with the institutional expansion of bike use facilities and work organizations and the improvement of facilities in accordance with urban rivers and bike-related regulations. Therefore, it is expected that the development of the living space will be beneficial for the citizens due to the elimination of traffic in the city and the activation of bike traffic.

• Korean Journal of Remote Sensing
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• v.29 no.4
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• pp.361-373
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• 2013

The monitoring of urban area, target detection and building reconstruction have been actively studied and investigated since high resolution X-band SAR images could be acquired by airborne and/or satellite SAR systems. This paper describes an efficient approach to reconstruct artificial structures (e.g. apartment, building and house) in urban area using high resolution X-band SAR images. Building footprint was first extracted from 1:25,000 digital topographic map and then a corner line of building was detected by an automatic detecting algorithm. With SAR amplitude images, an initial building height was calculated by the length of layover estimated using KS-test (Kolmogorov-Smirnov test) from the corner line. The interferometric SAR phases were simulated depending on SAR geometry and changable building heights ranging from -10 m to +10 m of the initial building height. With an interferogram from real SAR data set, the simulation results were compared using the method of the phase consistency. One of results can be finally defined as the reconstructed building height. The developed algorithm was applied to repeat-pass TerraSAR-X spotlight mode data set over an apartment complex in Daejeon city, Korea. The final building heights were validated against reference heights extracted from LiDAR DSM, with an RMSE (Root Mean Square Error) of about 1~2m.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1227-1240
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• 2014

Abandoned mines often cause environmental problems, such as alteration of landscape, metal contamination, and landslides due to a heavy rainfall. Geotechnical and rheological tests were performed on waste materials corrected from Imgi waste rock dump, located in Busan Metropolitan City. Debris flow mobility was examined with the help of 1-D BING model which was often simulated in both subaerial and subaqueous environments. To determine flow curve, we used a vane-penetrated rheometer. The shear stress (${\tau}$)-shear rate (${\dot{\gamma}}$) and viscosity(${\eta}$)-shear rate (${\dot{\gamma}}$) relationships were plotted using a shear stress control mode. Well-known rheological models, such as Bingham, bilinear, Herschel-Bulkley, Power-law, and Papanastasiou concepts, were compared to the rheological data. From the test results, we found that the tested waste materials exhibited a typical shear shinning behavior in ${\tau}$-${\dot{\gamma}}$ and and ${\eta}$-${\dot{\gamma}}$ plots, but the Bingham behavior is often observed when the water contents increased. The test results show that experimental data are in good agreement with rheological models in the post-failure stage during shearing. Based on the rheological properties (i.e., Bingham yield stress and viscosity as a function of the volumetric concentration of sediment) of waste materials, initial flowing shape (5 m, 10 m, and 15 m) and yield stress (100 Pa, 200 Pa, 300 Pa, and 500 Pa) were input to simulate the debris flow motion. As a result, the runout distance and front velocity of debris flow are in inverse propositional to yield stress. In particular, when the yield stress is less than 500 Pa, most of failed masses can flow into the stream, resulting in a water contamination.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.4
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• pp.419-430
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• 2007

Purpose: This in vitro study evaluated shear bond strengths of surface treatment porcelains with four porcelain repair systems simulating intraoral bonding of composite resin to feldspathic porcelain or pressable porcelain. Material and methods: Eighty Porcelain disks were prepared. Group A: forty disk specimens were fabricated with Feldspathic Porcelain($Omega^{(R)}900$, Vident, Menlo Park, CA, USA). Group B: forty disk specimens were fabricated with Pressable Porcelain(IPS Empress 2 ingot, Ivoclar-Vivadent, Schaan, Liechtenstein, Germany). Each groups was divided into 4 subgroups and composite resin cylinders were bonded to specimen with one of the following four systems: Clearfil Porcelain Bond(L. Morita, Tustin, CA, USA), Ulradent Porcelain Etch. (Ultradent, Salt Lake City UT, USA), Porcelain Liner-M(Sun Medical Co., Kyoto, Japan), Cimara Kit(Voco, Germany). After surface conditioning with one of the four porcelain repair systems substrate surfaces of the specimen were examined microscopically(SEM). Shear bond strengths of specimens for each subgroup were determined with a universal testing machine (5mm/min crosshead speed) after storing them in distilled water at $37{\pm}1^{\circ}C$ for 24 hours. Stress at failure was measured in $MP_a$, and mode of failure was recorded. Differences among four repair systems were analyzed with two way ANOVA and Duncan test at the 95% significance level. Results: In the scanning electron photomicrograph of the treated porcelain surface, hydrofluoric acid etched group appeared the highest roughness. The shear bond strength of the phosphoric acid etched group was not significantly(p>0.05) different between feldspathic porcelain and pressable porcelain. But in no treatment and roughened with a bur group, the shear bond strength of the feldspathic porcelain was significantly higher than that of the pressable porcelain. In hydrofluoric acid etched group, the shear bond strength of the pressable porcelain was significantly higher(p<0.05). Conclusion: 1. Treatment groups showed significantly greater shear bond strengths than no treatment group(p<0.05). 2. Group with more roughened porcelain surface did not always show higher shear bond strengths. 3. In phosphoric acid etched group, there was no significant difference in shear bond strength between feldspathic porcelain and pressable porcelain(p>0.05). However in the other groups, there were significant differences in shear bond strengths between feldspathic porcelain and pressable porcelain(p<0.05).

• Biomedical Science Letters
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• v.5 no.1
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• pp.1-10
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• 1999

This study was attempted to generate a monoclonal antibody against human $\alpha$-fetoprotein (AFP) and to produce an immunoassay, recognizing AFP in plasma and amniotic fluid. AFP was purified from human amniotic fluid and used to immunize mice. Spleens were taken from the mice and the cells were fused with mouse myeloma cells (Sp2/0-Ag-14) for the production of monoclonal antibodies by employing the hybridoma technology. As a result, a hybridoma cell line producing anti-AFP monoclonal antibody was cloned out and designated as MabF22. From isotyping analysis, it was found that monoclonal antibody MabF22 was IgG type with IgG1 heavy chain and k light chain. The binding specificity of MabF22 was analyzed by immunoblotting as well as by ELISA. MabF22 was highly specific, reacting with only AFP-containing samples. The binding affinity was determined by ELISA (free-capture mode) and Scatchard analysis. As a result, the value of Kd was 0.8$\times$10$^{-10}$M. The validity of the MabF22 for AFP assay was examined by two kinds of ELISAs, i.e., non-competitive and competitive ELISA. Both assays revealed that MabF22 reacted well with AFP in sample in a concentration-dependent manner. Standard curve and antibody titration curve were obtained by using purified AFP and MabF22. These results indicate that the monoclonal antibody produced in this study would be useful not only for research purposes but also for further development of immune-diagnostic kit for the measurement of AEP concentration.

• Journal of Preventive Medicine and Public Health
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• v.42 no.5
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• pp.298-304
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• 2009

Objectives : The aim of this study was to investigate the association of blood pressure levels with the common carotid artery intima-media thickness (CCA-IMT) and carotid plaques. Methods : Data were obtained from 2,635 subjects, aged 50 years and over, who participated in the Community Health Survey (a population-based, cross-sectional study) in Dong-gu, Gwangju city between 2007 and 2008. Participants were categorized into three groups according to blood pressure levels; normotensives (<120/80 mmHg), prehypertensives (120-139/80-89 mmHg), and hypertensives ($\geq$140/90 mmHg). Prehypertensives were further categorized as low prehypertensives (120-129/80-84 mmHg) and high prehypertensives (130-139/85-89 mmHg). Carotid intima-media thickness and plaques were evaluated with a high-resolution B-mode ultrasound. Statistical analyses were performed using chi-square test, ANOVA, and multiple logistic regression. Results : Prehypertensives had significantly greater maximal CCA-IMT values than normotensives, with a multivariate adjusted odds ratio of 1.78 (95% CI=1.36-2.32) for abnormal CCA-IMT (maximal CCA-IMT$\geq$1.0 mm), and 1.45 (95% CI=1.19-1.77) for carotid plaques. The multivariate adjusted odds ratio of low prehypertensives was 1.64 (95% CI=1.21-2.21) for abnormal CCA-IMT, and 1.30 (95% CI=1.04-1.63) for carotid plaques compared with normotensives. Subject with hypertension had higher frequency of abnormal CCA-IMT (odds ratio, 2.18; 95% CI=1.49-3.18), and carotid plaques (odds ratio, 1.98; 95% CI=1.46-2.67) compared with normotensives after adjustment for other cardiovascular risk factors. Conclusions : Our results indicate that there is a significant increase in the prevalence of carotid atherosclerosis in subjects with prehypertension (even in low prehypertensives) compared with normotensive subjects. Further studies are required to confirm the benefits and role of carotid ultrasonography in persons with prehypertension.