• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.685-691
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• 2009

The purpose of this paper is to classify the traffic condition in freeway by the impacts of road weather. The factor analysis showed that weather factors, which are considered as influential, are identified as weather condition (rain or clear), temperature and sight distance with RWIS and VDS data in Seohae bridge used. The result of ANOVA shows that weather is dividedinto clear and rainy; temperature into below and equal or above $5^{\circ}C$ and sight distance into below or equal or above 10km. Based on those factors, the freeway traffic condition has been classified as five different types. The flow-speed model for each traffic conditions was proposed, which was not significant due to the lack of smaple data. Although not sufficient, the methodology to categorize traffic situation model presented in this paper may shed light on the idea for the future and can be used for proper traffic management for each weather condition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.357-366
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• 2008

This study addresses the analysis of the behavioral characteristics of bridge expansion joints under wheel loading through wheel load test and the proposal of relevant wheel load specifications for expansion joints. To that goal, specimens of rail and finger expansion joints that are widely used in Korea were fabricated and subjected to static wheel load test using a real tire wheel. The wheel load distribution factor in the rail and finger expansion joints in contact with the wheel load was evaluated. The evaluation revealed that the portion of load sustained by the central rail of rail expansion joint was decreasing with larger wheel load, and that the portion of load sustained by the finger expansion joint was practically insensitive to the increase of the contact area and remained nearly constant. Since the wheel load characteristics showed large difference compared to former design specifications, it appears necessary to prepare rational specifications relative to the distribution of the wheel load contact pressure for the design of expansion joints.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5C
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• pp.343-350
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• 2006

The resistance bias factors for driven steel pipe piles are evaluated as a part of study to develop the LRFD(Load and Resistance Factor Design) for foundation structures in Korea. The 43 data sets of static load tests and soil property tests performed in the whole domestic area were collected and analyzed to determine the representative bearing capacities of the piles using various methods. Based on the statistical analysis of the data, the Davisson's criterion is proved to be the most reasonable method for estimation of pile bearing capacity among the methods used. The static bearing capacity formulas and the Meyerhof method using N values are applied to calculate the design bearing capacity of the piles. The resistance bias factors of the driven steel pipe piles are evaluated respectively as 0.98 and 1.46 by comparison of the bearing capacities for both of the static bearing capacity formulas and the Meyerhof method. It is also shown that uncertainty of the static bearing capacity formulas is relatively less than that of the Meyerhof method.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.4
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• pp.387-398
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• 2023

Conventional aquaculture faces declining productivity, shifting to recirculating aquaculture system (RAS), known for minimizing water usage and maintaining consistent water temperatures for year-round fish growth. Rainbow trout (Oncorhynchus mykiss), a globally important cold-water species and the third most farmed fish in inland waters of Korea, valued for its fecundity and rapid growth. Dissolved oxygen, an important environmental factor affecting fish production and economics, highlights the need for smart aquaculture practices. Since 2018, the rise of intelligent aquaculture platforms, incorporating information and communications technology (ICT), emphasizes the essential role of RAS implementation. This eight-week study aimed to determine the optimal dissolved oxygen concentration for rainbow trout in RAS, utilizing a device for continuous monitoring, control and record. Dissolved oxygen concentrations were set at 5-6 mg/L, 9-10 mg/L, 14-15 mg/L and 17-18 mg/L. The growth rate significantly decreased at 5-6 mg/L, with no significant differences in other experimental groups. In hematological analysis, growth hormone (GH) was significantly highest at 5-6 mg/L, followed by 9-10 mg/L while Insulin-like growth factor-1 (IGF-1) was significantly lowest at 5-6 mg/L. In conclusion, the optimal dissolved oxygen concentration for rainbow trout in RAS is approximately 9-10 mg/L. Higher concentrations do not contribute to further growth or profitability.

• Korean Journal of Radiology
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• v.24 no.6
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• pp.590-598
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• 2023

Objective: To investigate whether the levels of inflammation detected by 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) can predict disease relapse in immunoglobulin G4-related disease (IgG4-RD) patients receiving standard induction steroid therapy. Materials and Methods: This prospective study analyzed pretherapy FDG PET/CT images from 48 patients (mean age, 63 ± 12.9 years; 45 males and 3 females) diagnosed with IgG4-RD between September 2008 and February 2018, who subsequently received standard induction steroid therapy as the first-line treatment. Multivariable Cox proportional hazards models were used to identify the potential prognostic factors associated with relapse-free survival (RFS). Results: The median follow-up time for the entire cohort was 1913 days (interquartile range [IQR], 803-2929 days). Relapse occurred in 81.3% (39/48) patients during the follow-up period. The median time to relapse was 210 days (IQR, 140-308 days) after completion of standardized induction steroid therapy. Among the 17 parameters analyzed, Cox proportional hazard analysis identified whole-body total lesion glycolysis (WTLG) > 600 on FDG-PET as an independent risk factor for disease relapse (median RFS, 175 vs. 308 days; adjusted hazard ratio, 2.196 [95% confidence interval: 1.080-4.374]; P = 0.030). Conclusion: WTLG on pretherapy FDG PET/CT was the only significant factor associated with RFS in IgG-RD patients receiving standard steroid induction therapy.

• Journal of Korean Society of Rural Planning
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• v.13 no.2
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• pp.63-74
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• 2007

This study aims to develop rural house maintenance technique by researching and analyzing the demand for rural house by urban retirees or urbanites who are planning to retire. The target for the survey consisted of urban retirees or urbanites who are planning to retire at the ages between 40 and 65, and were divided into group A, the attendants in rural-related education, and group B, the non-attendants in rural-related education. The contents of the survey included the plan and purpose for rural settlement, the utilization form or residential form of rural house and its expected size, necessary in-house facilities, necessary community facilities, improvement and maintenance factors of rural house, political and legal support for the application of rural house maintenance, etc. The results findings of this study are as follows; 1)For both group, the major purpose of rural settlement appeared to be 'for rural life', utilization form of rural house to be 'acquired ownership or use of empty house', residential form to be 'cohabitation', expected size to be 'under $20{\sim}30$ pung', and expenditure to be 'under $50{\sim}100\;million$'. 2)Most wanted necessary in-house facilities included backyard, multipurpose storage room for group A, and backyard, garden for group B. Necessary community facilities included boardwalk, sewage disposal unit for group A, and boardwalk, shop for group B. 3)Improvement factor for rural house showed 'poor insulation' as first factor for both groups, and for maintenance factor, 'backyard', 'under-floor heating' for group A, and 'environmental-friendly materials', 'backyard' for group B. 4)Most wanted overall political and legal support included 'support on land and real estate supply' for group A, and 'medical and transportation service' for group B. For both group, most wanted support when purchasing a house included 'provision of information on house and realestate purchase', and for legal support, 'legal support for guaranteed house and maintenance' as first factor. The results of this study could be utilized to restructure the rural residence, which would meet the diverse demand of both rural residents and urbanites by providing an opportunity for urbanites to enjoy rural life.

• Atmosphere
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• v.25 no.2
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• pp.221-233
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• 2015

Pollen is closely related to health issues such as allergenic rhinitis and asthma as well as intensifying atopic syndrome. Information on current and future spatio-temporal distribution of allergenic pollen is needed to address such issues. In this study, the Community Multiscale Air Quality Modeling (CMAQ) was utilized as a base modeling system to forecast pollen dispersal from oak trees. Pollen emission is one of the most important parts in the dispersal modeling system. Areal emission factor was determined from gridded areal fraction of oak trees, which was produced by the analysis of the tree type maps (1:5000) obtained from the Korea Forest Service. Daily total pollen production was estimated by a robust multiple regression model of weather conditions and pollen concentration. Hourly emission factor was determined from wind speed and friction velocity. Hourly pollen emission was then calculated by multiplying areal emission factor, daily total pollen production, and hourly emission factor. Forecast data from the KMA UM LDAPS (Korea Meteorological Administration Unified Model Local Data Assimilation and Prediction System) was utilized as input. For the verification of the model, daily observed pollen concentration from 12 sites in Korea during the pollen season of 2014. Although the model showed a tendency of over-estimation in terms of the seasonal and daily mean concentrations, overall concentration was similar to the observation. Comparison at the hourly output showed distinctive delay of the peak hours by the model at the 'Pocheon' site. It was speculated that the constant release of hourly number of pollen in the modeling framework caused the delay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.35-44
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• 2018

The purpose of this study was to derive the factors that affect the development cost and the priority/weight of effectiveness in the pre-development stage of a service robot to estimate the development cost. In particular, the functions of service robots vary according to the field of application, and their prices are not only different but most of them are small-scale production; hence, a cost estimation is necessary. In this research, the factors affecting the service robot development cost in the process of service robot development and adding functions are classified as a functional factor while the factors that affect the entire development cost due to environmental causes, in which the service robot is operated or in the development process, are classified as an adjustment factor. The FGI was conducted to derive the factors and a Delphi survey was conducted among 84 domestic experts to determine the weights of the factors. As a result of the analysis, six functional factors (41 detailed criteria) and five adjustment factors (17 criteria) were derived, the cost weight and rank of the factors were suggested. This study suggests that the development cost of the service robot can be used as a decision-making strategy to select the operation functions in the development process, and can be utilized as an essential tool for the service robot development.

• Journal of the Korea Convergence Society
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• v.6 no.6
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• pp.27-34
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• 2015

Abstract The purpose of this study is to analyze the changes in job satisfaction and turnover intention according to the level of Emotional labor and the mediating effect in dental hygienists. Higher levels of emotional labor resulted in lower levels of job satisfaction, as well as higher levels of turnover intention. We used the logistic regression analysis to compare change of job satisfaction, turnover intention according to the level of emotional labor. In logistic regression analyses, social support was the largest mediating factor between emotional labor and job satisfaction and the odds(Likely to with low job satisfaction) was down by 16% after adjustment for supervisor, colleague. In case of turnover intention, largest mediating factor were drinking, physical condition, supervisor, colleague and the odds(Likely to with high turnover intention) was down by 52% after adjustment for mediating factors. The results of this study were as follows. Emotional labor was negatively impact on job satisfaction and turnover intention. To increase the job satisfaction and lower the turnover intention, it is necessary to do more efforts to improve social support(supervisor and colleague) and management personal factor(drinking, physical condition) for the dental hygienists should be made to reduce such negative effects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.1
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• pp.53-62
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• 1982

An effort of preliminary type has been made to develope a practical method for the waterway area determination of a drainage outlet in rural or agricultural areas. The Seoul meteorological station was selected as tile index station, and the maximum rainfalls-duration-frequency (R-D-F) relation of short-time intense rainfalls was first established. A frequency analysis of the daily rainfalls for the 75 stations selected throughout the country resulted the 50-year daily rainfall for each station. The rainfall factor, which is defined here as the ration of 50-year daily rainfalls of individual station and the index station, was determined for the 8 climatological regions divided in this study. Following the US SCS method the runoff number of a watershed was given based on the soil type, land-use pattern, and the surface treatment. With this runoff number and the R-D-F relationship the runoff factors for the index station were computed and hence a nomogram could be drawn which makes it possible to determine the runoff factor for a given rainfall number and a rainfall of specific duration and frequency. With this done, the potential runoff of a watershed for a given rainfall duration could be calculated, based on the unit hydrograph theory, by multiplying the rainfall factor, the runoff factor, and the drainage area of the watershed under consideration. Then, the maximum runoff potential was determined by varying the rainfall duration and finding out the duration which results the peak discharge of a gived return period.