• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.689-699
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• 2000

This paper presents the integrated storage function model (ISFM) to improve the accuracy of the storage function model (SFM) which is widely employed for flood runoff analysis and its forecasting in Korea. In order to achieve this objective, the optimization method is applied for estimation of parameters of the model which dominate the accuracy of the analysis, which is usually taken by empirical formulae, and they are treated as time dependent variables. The fuzzy control technique is used to detennine the time variant parameters. In addition, the ISFM can be applied to the combined routing of the watershed and the channel with a residual watershed.ershed.

• Journal of Environmental Health Sciences
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• v.33 no.3
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• pp.207-210
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• 2007

The study was designed to determine the estrogenic effect of some penicillins on endocrine function in adult Japanese medaka (Oryzias latipes). Vitellogenin (Vtg) produced in male fish has been used for a biomarker to study endocrine disrupters. $17\beta-estradiol\;(E_2)$ was used a positive control that was induced Vtg in male fish. Result of total protein qantification and ELISA for female and male fish were exposed to $17\beta-estradiol$ 10ng/ml for $3\sim5$ days. As a result, male fish exposed to amoxicillin respectively appeared 0.75, 0.23, 8.21 and $9.36\%_{\circ}$ of 1, 10, 100 and 1000 ppm respectively, that value was elevated compared with control male fish. Male fish exposed to ampicillin respectively appeared 1.85, 4.68, 0.85 and $39.59\%_{\circ}$ of 1, 10, 100 and 1000 ppm respectively, that value was elevated compared with control male fish. This study is one of the first reports suggesting potential endocrine disruption of some penicillins in aquatic ecosystem. These results suggest that vitellogenin and estrogen receptor induction patterns alter in male medaka treated with selected estrogenic compounds, and that these results may be useful molecular biomarkers for screening estrogenic EDCs (endocrine-disrupting chemicals) in the shortest possible time.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.1-21
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• 2003

I introduce the Flexible Dam Operation (FDO) and some of sediment control techniques In dams which are implemented as trials to avoid or reduce environmental impact of dams on the downstream reaches. The FDO is a dam management method to improve river environment in the downstream reaches by means of the flushing flow, the maintenance flow and so on utilizing a vacant portion of capacity for flood control without interrupting prime flood control function during the rainy/typhoon season. It Is suggested by the guideline of the FDO that EDO should be implemented regularly after the trial for about three years. The basic conception of the FDO is described here. The example of excavation of deposited sediments in check dams and placement of sand ana gravel immediately downstream of the dams and the example of coordinated sediment flushing are described as some of sediment control techniques in dams. Now they are at the stage of experiment and trial. Therefore, it is important to increase examples and establish the technical methodology and the environmental evaluation method for them.

• Journal of Korean Biological Nursing Science
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• v.10 no.2
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• pp.176-183
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• 2008

Purpose: The purpose of this study was to identify the effect of Environmental Enrichment (EE) on improvement of motor function in animal models of Parkinson's Disease. Methods: Male C57BL6 mice weighing 25-30 g, at the age of 12 wks were used in this study. The animals were injected MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin, 20 mg/kg in saline, i.p.) 4 times a day at every 2 hr, and raised in EE cage for 14 days. On day 14, after behavior test, all mice were sacrificed for immunohistochemistry. All values were expressed as means$\pm$S.E.M. Statistical significance was evaluated using a one way ANOVA followed by Sheffe test. Results: There was a significant difference between the experimental group and the control group in the behavior test. Also EE significantly reduced of TH positive cell loss in Substantia nigra pars compacta as compared to the result of MPTP treatment. Conclusion: Based on these findings, it is reasonable to assume that the environmental enrichment prevents dopaminergic neuronal loss and improves disarrangement of motor function and behavioral disability induced by MPTP.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.1
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• pp.143-152
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• 2020

PURPOSE: This study examined the effects of videoconferencing-based telerehabilitation exercise program on the gait, knee function, and quality of life of patients with knee osteoarthritis. METHODS: Forty-eight subjects, who were diagnosed with osteoarthritis of the knee by the radiologic findings, history, and a physical examination, were assigned randomly to a Control group, Experiment group I, and Experiment group II. The control group did not perform any exercise program and were educated in understanding and managing the disease of knee osteoarthritis for only one hour. Experimental groups I and II were provided with an exercise guidelines book for knee osteoarthritis, and the same exercise programs were conducted by face-to-face visits and non-face-to-face using telerehabilitation for eight weeks, respectively. To verify the effectiveness of each exercise program, the gait speed, knee disability index, and health related quality of life were measured. All assessments were conducted twice before and after the intervention. RESULTS: The participants who underwent both face-to-face and telerehabilitation exercise programs showed an improved gait speed, knee function, and health-related quality of life. In particular, there was no significant difference between the telerehabilitation exercise group and the direct face-to-face exercise group in improving the knee joint function and health related quality of life. CONCLUSION: A these findings the telerehabilitation exercise program for patients with knee osteoarthritis can alternate or supplement the face-to-face exercise program. Therefore, the telerehabilitation exercise program should be used not only as a substitute supplement program but also as an intervention for various diseases.

• Geomechanics and Engineering
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• v.19 no.4
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• pp.343-352
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• 2019

For quality control and the economical design of grouted sand, the prior establishment of the unconfined compressive strength (UCS) estimating formula is very important. This study aims to develop an empirical UCS estimating formula for grouted sand based on the physical properties of sands and the UCS of cured pure grout. Four sands with varying particle sizes were grouted with both microfine cement and Ordinary Portland cement. Grouted specimens were prepared at three different relative densities and at three different water-to-cement ratios, and unconfined compression tests were performed. The results demonstrate that UCS of grouted sand can be expressed as the power function of the UCS of cured pure grout: $UCS_{grouted\;sand}/1MPa=A_{soil}{\cdot}(UCS_{pure}/1MPa)^N$. Because the exponent N strongly depends on the combination of pore area and pore size, N is expressed as the function of porosity (n) and specific surface ($S_a$). Additionally, because $S_a$ determines the area of the sand particle that cement particles can adsorb and n determines the number of cementation bondings between sand particles, $A_{soil}$ is also expressed as the function of n and $S_a$. Finally, the direct relationship between $A_{soil}$ and N is also investigated.

• Advances in concrete construction
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• v.7 no.3
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• pp.183-189
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• 2019

In this study, it has been tried to prepare an analytical fragility curves for isolated straight continues highway bridges by considering different spectral intensity measures. A three-span concrete isolated bridge has been selected and the seismic performance of the bridge has been improved by Lead Rubber Bearing (LRB). Incremental Dynamic Analysis (IDA) is applied to the bridge in longitudinal direction. A suite of 14 earthquake ground motions from medium to sever motions are scaled and used for nonlinear time history analysis. Fragility function considers the relationship of earthquake intensity measures (IM) and probability of exceeding certain Damage State (DS). A full three dimensional finite element model of the isolated bridge has been developed and analyzed. A wide range of different intensity measures are selected and the optimal intensity measure which has the less dispersion is proposed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.286-292
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• 2016

Objectives: This study aimed to evaluate the effects of chronical exposure to high-level dusts on cellular immune function. Methods: The subjects were 110 male workers, among whom 60 were chronically exposed to high-level dusts in mica, limestone and iron mines. The remaining 50 were office workers. Ambient total, respirable dust and crystalline silica in the workplace were sampled using personal air samplers and analyzed according to NIOSH method 0500. Serum levels of hydrogen peroxide, lipid peroxide and superoxide misutase activity were measured using absorption chromatography. The subpopulations of CD4+, CD8+, natural killer cells (CD16+) and CD3+ T-lymphocytes were examined by two-color staining using monoclonal antibodies. Results: The concentration of hydrogen peroxide was significantly higher in exposed workers and superoxide dismutase activity was significantly higher in control workers. No significant difference in numbers of T-lymphocyte subpopulations were observed between exposed and control workers. A significant correlation in exposed workers was observed among total dusts, respirable dusts and crystalline silica. Hydrogen peroxide was significantly correlated with total dust (r=0.720, p<0.01), respirable dust (r=0.770, p<0.01) and crystalline silica (r=0.678, p<0.01). Concentration of hydrogen peroxide showed a significantly negative correlation with numbers of CD8+ cells (r=-0.274, p<0.01), CD3+ cells (r=-0.222, p<0.01) and natural killer cells (r=-0.556, p<0.01). Conclusions: These results suggest that chronical exposure to high-level dust affects cellular immune function and effects might mediate through reactive oxygen species and inflammatory response.

• Smart Structures and Systems
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• v.21 no.5
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• pp.653-668
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• 2018

This work proposes and investigates re-centering negative stiffness dampers (NSDs) for vibration suppression in high-speed trains. The merit of the negative stiffness feature is demonstrated by active controllers on a high-speed train. This merit inspires the replacement of active controllers with re-centering NSDs, which are more reliable and robust than active controllers. The proposed damper design consists of a passive magnetic negative stiffness spring and a semi-active positioning shaft for re-centering function. The former produces negative stiffness control forces, and the latter prevents the amplification of quasi-static spring deflection. Numerical investigations verify that the proposed re-centering NSD can improve ride comfort significantly without amplifying spring deflection.

• Smart Structures and Systems
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• v.20 no.1
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• pp.23-33
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• 2017

Variable Curvature Friction Pendulum (VCFP) bearing is one of the alternatives to control excessive induced responses of isolated structures subjected to near-fault ground motions. The curvature of sliding surface in this isolator is varying with displacement and its function is non-spherical. Selecting the most appropriate function for the sliding surface depends on the design objectives and ground motion characteristics. To date, few polynomial functions have been experimentally tested for VCFP however it needs comprehensive parametric study to find out which one provides the most effective behavior. Herein, seismic performance of the isolated structure mounted on VCFP is investigated with two different polynomial functions of the sliding surface (Order 4 and 6). By variation of the constants in these functions through changing design parameters, 120 cases of isolators are evaluated and the most proper function is explored to minimize floor acceleration and/or isolator displacement under different hazard levels. Beside representing the desire sliding surface with adaptive behavior, it was shown that the polynomial function with order 6 has least possible floor acceleration under seven near-field ground motions in different levels.