• Archives of Pharmacal Research
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• v.28 no.5
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• pp.541-545
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• 2005

Flowers of Erigeron annuus L. were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH, and H$_2$O. Repeated silica gel and OD S column chromatography of the EtOAc fraction led to the isolation of a sterol, through activityguided fractionation, using ACAT inhibitory activity measurements. From the physico-chemical data, including NMR, MS, and IR, the chemical structure of the compound was determined to be an ergosterol peroxide (1), which has been isolated for the first time from this plant. This compound exhibited hACAT-1 and Lp-PLA$_2$ inhibitory effects, with inhibitory values of 51.6 ${\pm}$ 0.9 and 51 .7 ${\pm}$ 1.2%, at a treatment concentration of 0.23 mM.

• Restorative Dentistry and Endodontics
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• v.38 no.2
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• pp.65-72
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• 2013

Objectives: To evaluate the inhibitory effect of ursolic acid (UA)-containing composites on Streptococcus mutans (S. mutans) biofilm. Materials and Methods: Composite resins with five different concentrations (0.04, 0.1, 0.2, 0.5, and 1.0 wt%) of UA (U6753, Sigma Aldrich) were prepared, and their flexural strengths were measured according to ISO 4049. To evaluate the effect of carbohydrate source on biofilm formation, either glucose or sucrose was used as a nutrient source, and to investigate the effect of saliva treatment, the specimen were treated with either unstimulated whole saliva or phosphate-buffered saline (PBS). For biofilm assay, composite disks were transferred to S. mutans suspension and incubated for 24 hr. Afterwards, the specimens were rinsed with PBS and sonicated. The colony forming units (CFU) of the disrupted biofilm cultures were enumerated. For growth inhibition test, the composites were placed on a polystyrene well cluster, and S. mutans suspension was inoculated. The optical density at 600 nm ($OD_{600}$) was recorded by Infinite F200 pro apparatus (TECAN). One-way ANOVA and two-way ANOVA followed by Bonferroni correction were used for the data analyses. Results: The flexural strength values did not show significant difference at any concentration (p > 0.01). In biofilm assay, the CFU score decreased as the concentration of UA increased. The influence of saliva pretreatment was conflicting. The sucrose groups exhibited higher CFU score than glucose group (p < 0.05). In bacterial growth inhibition test, all experimental groups containing UA resulted in complete inhibition. Conclusions: Within the limitations of the experiments, UA included in the composite showed inhibitory effect on S. mutans biofilm formation and growth.

• Journal of the Economic Geographical Society of Korea
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• v.10 no.4
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• pp.427-443
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• 2007

The purpose of this study is to investigate spacio-temporal structures of traffic flows on the subway network in the Metropolitan Seoul, and the relationships between topological structures of traffic flows and land use patterns. In particular we analyze in the topological structures of traffic flows on the subway network in time dimension as well as in spatial dimension. For the purpose, this study utilizes data mining techniques to the one day T-card transaction data of the last four years, which has developed for exploring the characteristics of traffic flows from large scale trip-transaction databases. The topological structures of traffic flows on the subway network has changed considerably during the last four years. The volumes of traffic flows, the travel time and stops per trip have increased until 2006 and decreased again in 2007. The results are visualized by utilizing GIS and analyzed, and thus the spatial patterns of traffic flows are analyzed. The spatial distribution patterns of trip origins and destinations show substantial differences among time zones during a day. We analyze the relationships between traffic flows at subway stops and the geographical variables reflecting land use around them. We obtain 6 log-linear functions from stepwise multiple regression analysis. We test multicollinearity among the variables and autocollelation for the residuals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.13-22
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• 2012

The 119 emergency rescue-aid service operated by Korean government is a very valuable in a society and its importance is growing in Korea as an aging society. Especially, the emergency vehicle's arrival time to accidents place is an important variable which affects initial emergency measure for patients and it depends on the road network attributes, such as emergency service station's location, accessibility to accidents place and so on. This study aims to analysis the emergency vehicles' arrival delay and the dispatch station in the viewpoint of efficiency utilizing the real rescue-aid activity data. We analyzed the dispatch distribution of the emergency rescue-aid service at first. And we analyzed high accident rate locations not involved in the fixed radius of rescue-aid service stations and display GIS map showing regions have been delayed. The input data of the road network speed is based on the KTDB (Korea Transportation Database) and historical rescue-aid data is from Gyeongsangbuk-do's fire service headquarters.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.67-75
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• 2022

The purpose of this paper is to provide basic data to Si and Gun preparing for rural agreements in the future through consideration and case analysis for rural conventions, such things as living standards, hierarchical analysis methods, and general rural development projects. In the 1970s, sporadic and one-off projects focused on individual projects were repeatedly carried out in rural areas, which were undergoing dramatic changes in population movement, land use, landscape, economic growth and living. The keyword of the government's policy has changed to a way that existing rural development projects are planned and promoted by local governments themselves in conjunction with the issue of autonomy and decentralization. In addition, with the introduction of Rural Convention, the central and local governments are striving to achieve common policy goals. However, due to the lack of understanding of the Rural Convention introduced as a pilot project in 2020, the lack of living areas setting-standards, unclear classification of hierarchical structure, and excessive goal consciousness for general agricultural and fishing village development projects remain, fading the original purpose of the Rural Convention. Therefore, this study analyzed the seven reports of the Gyeongsang region selected in the 2021 Rural Convention to identify the characteristics of living area, hierarchical structure analysis, and detailed projects (rural center revitalization project, basic living base development project) and provided them as basic data. As a result of the study, first, according to the results of the hierarchical structure analysis, the first class was derived from 6 out of 7 Si and Gun. This is judged to be the result of the current rural population, social, and economic problems. Second, according to the results of the division of living areas, it was confirmed that except for one local government in seven cities and counties, the remaining six local governments were divided into three single living areas and three two living areas. This is the result obtained through a comprehensive review by overlapping the results of various analyses such as hierarchical analysis and resident surveys and OD data, and shows a different form from the existing upper or related plans. It is judged that this is the result of including qualitative contents such as residents' opinions along with various analyses when determining the living area. Third, the proportion of the budget for rural center revitalization and basic living base development projects to the total project cost subject to the Rural Convention was 59.6%, which was relatively higher than that of other general agricultural and fishing village development projects. It is judged that it is preferred because the unit project cost is relatively high in Si and Gun, and that quantitative results can be visually shown after the project is terminated.

• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.165-179
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• 2005

The object of this study is a development of a stochastic user equilibrium transit assignment algorithm for multiple user classes considering stochastic characteristics and heterogeneous attributes of passengers. The existing transit assignment algorithms have limits to attain realistic results because they assume a characteristic of passengers to be equal. Although one group with transit information and the other group without it have different trip patterns, the past studies could not explain the differences. For overcoming the problems, we use following methods. First, we apply a stochastic transit assignment model to obtain the difference of the perceived travel cost between passengers and apply a multiple user class assignment model to obtain the heterogeneous qualify of groups to get realistic results. Second, we assume that person trips have influence on the travel cost function in the development of model. Third, we use a C-logit model for solving IIA(independence of irrelevant alternatives) problems. According to repetition assigned trips and equivalent path cost have difference by each group and each path. The result comes close to stochastic user equilibrium and converging speed is very fast. The algorithm of this study is expected to make good use of evaluation tools in the transit policies by applying heterogeneous attributes and OD data.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.1 s.9
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• pp.1-12
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• 2006

In order to estimate a dynamic origin and destination demand between on and off-ramps in the freeways, a traffic flow theory can be used to calculate a link distribution proportion of traffics moving between them. We have developed a dynamic traffic estimation model based on the three-phase traffic theory (Kerner, 2004), which explains the complexity of traffic phenomena based on phase transitions among free-flow, synchronized flow and moving jam phases, and on their complex nonlinear spatiotemporal features. The developed model explains and estimates traffic congestion in terms of speed breakdown, phase transition and queue propagation. We have estimated the link, on and off-ramp volumes at every time interval by using traffic data collected from vehicle detection systems in Korea freeway sections. The analyzed results show that the developed model describes traffic flows adequately.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.100-115
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• 2020

Recently, with the development of various sensors and communication technologies, the market for wearable devices capable of recording physical activity in connection with a smartphone is expanding. The purpose of this study is to analyze physical activity for each transportation modes in order to utilize wearable devices in the field of transportation. This study consists of three steps: data collection, basic statistical analysis, and physical activity analysis. Four adult males and females were recruited as investigators, and physical activity and route information were collected through Fitbit, a commercial wearable device. From the collected physical activity information, a percentage of heart rate reserve (%HRR) using a heart rate was derived and used for analysis. As a results, it was found that there is a statistically significant difference in heart rate for each transportation mode, and physical activity intensity is the highest when walking. In addition, the results of physical activity analysis for the case of using different routes for the same OD were presented. The results presented in this study are expected to be used as basic data for preparing public transportation activation policies and providing customized services for the future.

• Journal of Korean Society of Transportation
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• v.30 no.2
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• pp.29-42
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• 2012

Recently, traffic congestion has become serious due to increase of private car usages. Carsharing or other innovative public transportation systems were developed to alleviate traffic congestion and carbon emissions. These measures can make the traffic environment more comfortable, and efficient. Cloud Transportation System (CTS) is a recent carsharing model. User can rent an electronic vehicles with various traffic information through the CTS. In this study, a concept, vision and scenarios of CTS are introduced. And, authors analyzed the location of CTS rental stations and estimated CTS demands. Firstly, we analyze the number of the population, employees, students and traffic volume in study areas. Secondly, the frequency and utilization time are examined. Demand for CTS in each traffic zone was estimated. Lastly, the CTS rental station location is determined based on the analyzed data of the study areas. Evaluation standard of the determined location includes accessibility and density of population. And, the number of vehicles and that of parking zone at the rental station are estimated. The result suggests that Haewoondae Square parking lot would be assigned 11 vehicles and 14.23 parking spaces and that Dongbac parking lot be assigned 7.9 vehicles and 10.29 parking spaces. Further study requires additional real-time data for CTS to increase accuracy of the demand estimation. And network design would be developed for redistribution of vehicles.

• The Korean Journal of Emergency Medical Services
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• v.1 no.1
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• pp.100-111
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• 1997

This is the first Korea study to evaluate the effects od the safety of ambulance driving and the occurrence of ambulance traffic accidents and to provide basic informaion for the description of various factors to reduce the ambulance traffic accidents. The major insturment of this study were Krean Self-Analysis Driver Opinionnaire. Questionnaire contains 8 items which measure driver's opinions or attitudes : driving courtesy, emotion, traffic law, speed, vehicle conditions, the use of drugs, high-risk behaviors, and human factors. To take the analysis of data, the total of 350 divers were investigated ambulance divers and others in Taejon City and others (6 City) from 1996. 1. July to 1996. 31. July. The data were analyzed by the descriptive statistics and the logistic regression - path analysis - with SPSS and SAS package program. The result are as follows : 1. There was desirable attitude group(16.2%) and undesirable attitude group(17.6%) on safety ambulance driving. 2. It have suggested that risk factors of ambulance traffic accidents much affected with emotion and speed control on safety ambulance driving < Y(Accdient) = -2.64 + 0.57 $X_1$ (Emotion Control) + 0.30 $X_2$(Seed control) + E > and motor traffic acident much affected with emotion control and high-risk behavior on safety driving < Y(Accident) = -1.11 + 0.33 $X_1$(Emotion Control) + 0.29 $X_2$(High-risk Behvior) + E > 4. The primary emphassis of ambulance drivers was make us realized that improthatnt factors on safety ambulance driving were 1)making way for emergent ambulance, 2)driver's career, 3)The ability of emergency medical technics, and the knowledge or under standing of ambulance way difficut(or easy) of accdess. 5. Almost 96.6% of respondents have agreed to necessity of emergency medical technics for ambulance drivers. 6. Almost 94.6% of respondents have consented to necessity of emergtency medical technicians for ambulance driving. 7. It have suggested that the proportion of traffic accident proportion by desitable attitude group(16.7%) was much less than that of undesirable attitude group(30.8%) on safety ambulance driving(P < 0.05)/Ps) Accidents are unplanned, unforesen incidents which can lead to harmful or unfortunate outcomes, Collisons are not accidents, since the basic cause of the majority of collisons invovles high-risk human behavior. Although there are many factors which contribute to accident causation, four basic factors seem to predominate in most traffic related situations. These four factors include: the human factor, the vehicle factor, the environmental factors and destination factor(Peto G. et al. 1995).