• KDI Journal of Economic Policy
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• v.35 no.4
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• pp.31-61
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• 2013

The purpose of this study is to calculate the economic value of transport demand forecasting risks in the road PPP project. Under the assumption that volatility of the road PPP project value occurs only in regard with uncertainty of traffic volume forecasting, this study calculates the economic value of the traffic forecasting risks in the case of the road PPP project. To that end, forecasted traffic volume is assumed to be a stochastic variable and to follow the Geometric Brownian motion as time passes. In particular, this study attempts to differentiate itself from existing studies that simply use an arbitrary assumption by presenting the application of different traffic volume growth volatility and the rates before and after the ramp-up period. Analysis of the case projects reveals that the risk premium related to traffic volume forecast of the project turns out as 7.39~8.30%, without considering option value-such as minimum revenue guarantee-while the project value volatility caused by transport demand forecasting risks is 17.11%. As the discount rate grows higher, the project value volatility tends to decrease and volatility in project value is always suggested to be larger than that in transport volume influenced by leverage effect due to fixed expenditure. The market value of transport demand forecasting risk-calculated using the project value volatility and risk premium-is analyzed to be between 0.42~0.50, implying that a 1% increase or decrease in the transport amount volatility would lead to a 0.42~0.50% increase or decrease in risk premium of the project.

• Clean Technology
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• v.23 no.4
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• pp.429-434
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• 2017

To investigate the effect of magnesium oxide addition, $Cu/ZnO/MgO/Al_2O_3$ (CZMA) catalysts were prepared using co-precipitation method with fixed molar ratio of Cu/Zn/Mg/Al as 45/45/5/5 mol% for low-temperature water gas shift reaction. Synthesized catalysts were characterized by using BET, $N_2O$ chemisorption, XRD, $H_2-TPR$ and $NH_3-TPD$ analysis. The catalytic activity tests were carried out at a GHSV of $28,000h^{-1}$ and a temperature range of $200{\sim}320^{\circ}C$. At the same condition, magnesium oxide added catalyst (CZMA 400) showed that the lowest reduction temperature and stable presence of $Cu^+$, that is active species and abundant weak acid site. Also magnesium oxide added catalysts (CZMA) showed higher catalytic activity at temperature range above $240^{\circ}C$ than the catalyst without magnesium oxide (CZA). Consequently, CZMA 400 catalyst is considered to be excellent catalyst showing CO conversion of 77.59% without deactivation for about 75 hours at $240^{\circ}C$, GHSV $28,000h^{-1}$.

• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.1-12
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• 2003

The purpose of this study was to investigate the effect of high voltage pulsed current stimulation (HVPCS) on the healing rate of a dermal wound in a rat. We also determined the mechanism of promoting healing by HVPCS. Twenty male Sprague-Dawley rats were randomly divided into two group; HVPCS group (n=10) and control group (n=10). The HVPCS rats received electrical stimulation with a current intensity of 50 V at 100 pps for a duration of 30 minutes, while the control group was given the same treatment without electricity for a week. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with Masson's trichrome, hematoxylin and eosin (H&E). The fibroblasts and collagen density were counted using a light microscope and computerized image analysis system and calculated as the density and the percent. A Student t-test showed a significantly higher wound healing rate of the HVPCS group than control (t=-4.161, p<0.001). The fibroblasts in the HVPCS group were higher than in the control group (t=-4.921, p<0.001). The density of collagen in the HVPCS group was also higher than in the control group (t=-4.367, p<0.001). These results indicate that the HVPCS accelerated the rate of healing in dermal wound, and increased fibroblasts and collagen density in the regenerative dermis. These findings suggest that the HVPCS may activate fibroblasts by alteration of the electrical environment, and it may increase collagen synthesis in the regenerative dermal wound.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.115-123
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• 1998

Vinyl chloride monomer exists as gas phase at normal temperature and reacts with oxygen and strong oxidant in the air to form oxidized materials. Because of being easily synthesized, it is used as a main source at the synthetic reaction process of PVC synthesis factories. Ministry of Labor regulates its usage as a carcinogen and its exposure level as 1 ppm. But the amount of VCM production in PVC and VCM production process hasn't been exactly estimated. In addition, facilities of this factory are located in outdoor. Therefore, this study was designed to investigate effects of temperature on breakthrough of charcoal tube at a fixed concentration and temperature during VCM sampling based on NIOSH and OSHA methods which were used as methods of occupational environment measuring and analysis. During the sampling of VCM, methods of OSHA and NIOSH require flow rate of 0.05 lpm and sampling volume of $3{\ell}$, $5{\ell}$ respectively, at this time carbon molecular sieve tube and coconut shell charcoal tube are used to observe the breakthrough along with concentration and temperature. As a result, significant difference between average adsorbed amounts of OSHA methods but that of NIOSH methods cannot be found. NIOSH method is likely to be effected by high temperature and normal temperature in high concentration. Breakthrough is not found in the method of OSHA at different conditions of temperature and concentration. As the result of this study we could verify that breakthrough occurred in the process of sampling VCM with NIOSH methods. Therefor in summer time, breakthrough should be considered and research on the breakthrough volume should be done. It is considered the research about the specificity of the coconut shell charcoal and carbon molecular sieve sorbent should be done when sampling VCM in comming days.

• 한국해양학회지
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• v.26 no.2
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• pp.117-132
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• 1991

Marine total magnetic intensity over the southern part of the Ulleung Basin and geomagnetic data measured at a land base station are analyzed. Fourteen days observation of geomagnetic field at a fixed on-land base station showed how the geomagnetic field around the study area behaves. geomagnetic data at the base station can also be used as correction data for a diurnal variation. Magnetic anomalies in the study area do not reflect an effect of sea bottom topography but mainly subsurface basement. The southern part of the Ulleung Basin can be devided into two zones according to a different anomaly pattern; along the coastal shelves the isolated anomalies with a short wave and a strong amplitude are dominant, and toward the open sea the anomalies become much more subdued. The high anomaly zone adjoined to land is interpreted to be caused by granitic intrusives or volcanic rocks, and the weak anomaly zone to the outer sea to be arisen from an existence of deep basement. A spectrum analysis is applied to estimate magnetic basement depths from three anomaly profiles with a long period and a weak amplitude toward the outer sea. The calculated depths are 7.0km, 5.0km, and 2.6km respectively from outer profile. The basement might be correlated with the mixed layer of tuff, basalt, and sediment, which had been defined as L-2 layer in the Yamato basin and the Japan Basin.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.4
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• pp.255-260
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• 2013

In this paper, we propose the effective bit expansion of FFT module for improving the accuracy of correlation result of the Daejeon correlator. The Daejeon correlator based on FPGA was implemented in order to fast data processing with the fixed-point of FFT operation. In correlation result, however, the phenomenon of phase concentration to 0 degree was appeared in lower frequency area of bandwidth due to lack of operational bit. This phenomenon has an affect on the accuracy of correlation result by introducing the effect of data loss because of excluding phase concentration during analysis of observed radio source. In order to improving the accuracy of correlation result we carried out the simulation by expanding bit-number than 16-bit operation of previous FFT module within given resource limits of FPGA. Through the simulation results, the effective bit number for FFT module within used FPGA resource limits is able to expand, and we confirmed that the operational 20-bit of FFT module is effective for improving accuracy of correlation result by comparing with experimental result.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.1-7
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• 2000

The purpose of this study was to determine the effect of microamperage electrical stimulation on the number of argyrophilic nucleolar organizer region (AgNOR) in rat skin. Twenty four male Sprague-Dawley rats were divided into electrical stimulation and control group. Bach animals hair on the back was removed. The electrical stimulation group received an positive rectangular positive electrical stimulation with $500{\mu}A$, while the control group was given the same treatment without electricity. The rats were sacrificed at 4 and 7 day of stimulation, respectively. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with silver nitrate. The AgNOR were counted using a light microscope and computerized image analysis system and calculated as the mean number of AgNOR per nucleus in the epidermal keratinocyte. In control skin, the mean AgNOR count of epidermal keratinocyte at 4 and 7 day were 1.67 and 1.72, whereas electrical stimulated rat had mean AgNOR counts of 2.0 and 2.14, respectively. A Student's t-test showed a significantly higher mean AgNOR number at 4 ana 7 day in the electrical stimulated rats than control rats (p<0.05). The microamperage electric current stimulation increased the epidermal AgMOR expression in incisional wound skin. These results suggest that the microamperage electrical stimulation may promote migration and proliferative activity of epidermal keratinocyte in surgical wound.

• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.402-408
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• 2005

The purpose of this study was to investigate the effects of estrogen deficiency on pulpodentinal complex of tooth in ovariectomized rats. Thirty female Sprague-Dawley rats, 10 weeks old, were used. Rats were grouped into two groups. One group (n = 15) was subjected to sham surgery (SHAM) and the other group (n = 15) was ovariectomized bilaterally (OVX). Animals were sacrificed 12 weeks later, and their mandibular molars and associated periodontal supporting tissues were dissected out, and fixed in $10\%$ buffered formalin. For comparison of groups, immunostained for osteonectin. Histomorphometrical measurement of change of teeth was performed using an image analysis system and paired t-test was used and the level of significance for overall differences was set at p < 0.05. In immunostaining of osteonectin, they were significantly different from each other. The predentin thickness in OVX rats was wider than in SHAM rats. And in SHAM rats, osteonectin was more specifically stained in predentin areas than in OVX rats. These results indicate that estrogen deficiency increased the unmineralized predentin areas and decreased osteonectin content in pulpal tissues in rats. If our result is applicable to human studies, odotoblast is affected by estrogen deficiency.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.183-190
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• 2011

Loan amount of housing mortgage is composed of various factors. This study paper studies focuses on estimating the determinants of a loan amount of housing mortgage. The region for analysis consist of seven groups, that is, metropolitan city (such as Busan, Daegu, Incheon, Gwangiu, Daejeon, Ulsan.) and Seoul. Analyzing period be formed over a 45 time points(2007. 01.~ 2010. 09). In this paper the dependent variable setting up loan amount of housing mortgage, explanatory(independent) variables are composed of the consumer price index, unemployment rate, average monthly household income per household, expenditure rate of health care, composite stock price index and overdue rate of household loans for commercial bank. In looking at the factors which determine loan amount of housing mortgage, evidence was produced supporting the hypothesis that there is a significant positive relationship between the consumer price index and unemployment rate. The study also produced evidence supporting the view that there is a significant negative relationship between expenditure rate of health care. The study found that average monthly household income per household, expenditure, composite stock price index and overdue rate of household loans for commercial bank were not significant variables. The implications of these findings are discussed for further research.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.417-423
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• 2014

The aim of this study was to evaluate the relationship between prosthetic status and health related quality of elderly by using EuroQol-5 dimension (EQ-5D) which is a standardized instrument used as a measure of health outcome. Data from 1,179 elderly subjects (over 65 years old) from the fifth Korea National Health and Nutrition Examination Survey were used in our analysis. Oral examination were conducted to obtain wearing prosthetic and needed prosthetic. EQ-5D is a widely used health condition measuring instrument. It consists of the five dimensions: Mobility, Self-care, Usual activities, Pain/discomfort and Anxiety/depression. EQ-5D index is a score calculated out of a weighting system. In this study, the mean score of the EQ-5D index among the elderly was 0.86. For EQ-5D index gender, female showed statistically significantly lower quality of life than male. The related factors EQ-5D index, when the lower demand for fixed prosthodontics and full denture. Wearers in partial and complete denture than non-wearers showed higher EQ-5D index. In order to improve EQ-5D index among the elderly who demand prosthetic status, which has lost its function through providing proper dental prostheses.