• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.59-72
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• 2007

This study executed to offer the basis for dental technology student who chanced better clinical training. This investigation conducted on 267 of seniors who have been taken clinical training to self written a questionnaire. We used and dealt a spss 12.0 program. Study results below 1. In a question about relationship, one answered "Harmonious" took largest proportion by 40.9% during training, and about the degree of satisfaction of campus life who answered :normal: were the most with 50.0% 2. In a question about clinical training place, most(50.0%) choose place less than 10 for clinical training, and more than 10 for clinical training with 29.7%. Residue statues was most of them resided own home with 78.6%. About their commuting time from home to training place, 50.0% was under 30min, 34.1% took time 30$\sim$60min. 3. In a question about clinical trainer, most (34.4%) choose as dental lab president, as each part manager with 34.1%, a senior with 7.6% and not exist to clinical trainer with 7.6%. 4. A perfect score about teaching efficiency and satisfaction of clinical practice of dental technology students was 5. The average of score about satisfaction of clinical practice was 3.25 and circumstance of clinical training got 3.50 as a highest score. the lowest score was 2.87 that is about satisfaction of clinical training period. The average of score of teaching efficiency was 3.25. 'a Role model' got 3.55 as the highest score and 'utility for student' got 3.12 as the lowest 3.12. 5. The result of T-test to see of the satisfaction according to the general character and clinic training condition between teaching efficiency is that the degree of satisfaction of clinical training showed statistical significance only in the degree of satisfaction of college life(p<0.05), teaching efficiency has a statistical significance with age and satisfaction of college life(p<0.05). 6. The relation between of teaching efficiency of clinical training and satisfaction of clinical training of dental technologic student has a statistical relation r=0.551 and a statistical meaning in significance leveler 0.01.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.121-133
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• 2017

Since the mid 1990s, policies have been actively promoted to improve safety and pedestrian environment around the school such as the improvement of School zone. However, the prevention of accidents was not effective because it did not extend to the school road where the main transportation route for children's commuting takes place. In addition, due to the rapid increase of automobiles, trunk road traffic in the peak time bypasses the back roads, which threatens children's safety and the environment by invading the school area, which is the main living space of children. In this study, the characteristics of domestic children's traffic accidents were investigated and the problems were analyzed by conducting a field survey on Yeouido Secondary School in Seoul and Unjung Elementary School in Gyeonggi Province. In addition, Variable speed limit signs and Beacons were installed in the pedestrian road of comunity including School zone, and the effects of facilities on the speed of vehicles were analyzed. As a result of the analysis, the Variable speed limit sign showed a deceleration effect of about 8.3km/h, and the Beacon showed a phenomenon in which the traveling speed of 0.8km/h increased only slightly. In addition, the traffic violation rate of passenger cars, buses, and lorries decreased by about 3% as a result of investigating the number of traffic violation vehicles before and after installation.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.1
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• pp.59-77
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• 2008

The purpose of this study is to investigate the impact of traffic-related air pollution on the urban population in the Metropolitan Seoul area. In particular, this study analyzes urban population exposure to traffic-related particulate materials(PM). For the purpose, this study examines the relationships between traffic flows and PM concentration levels during the last fifteen years. Traffic volumes have been decreased significantly in recent year in Seoul, however, PM levels have been declined less compare to traffic volumes. It may be related with the rapid growth in the population and vehicle numbers in Gyenggi, the outskirt of Seoul, where several New Towns have been developed in the middle of 1990's. The spatial pattern of commuting has changed, and thus and travel distances and traffic volumes have increased along the main roads connecting CBDs in Seoul and New Towns consisting of large residential apartment complexes. These changes in traffic flows and travel behaviors cause increasing exposure to traffic-related air pollution for urban population over the Metropolitan Seoul area. GIS techniques are applied to analyze the spatial patterns of traffic flows, population distributions, PM distributions, and passenger flows comprehensively. This study also analyzes real time base traffic flow data and passenger flow data obtained from T-card transaction database applying data mining techniques. This study also attempts to develop a space-time model for assessing journey-time exposure to traffic related air pollutants based on travel passenger frequency distribution function. The results of this study can be used for the implications for sustainable transport systems, public health and transportation policy by reducing urban air pollution and road traffics in the Metropolitan Seoul area.

• Korean Journal of Biological Psychiatry
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• v.24 no.2
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• pp.59-67
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• 2017

Shift workers experience a disruption in the circadian sleep-wake rhythm, which brings upon adverse health effects such as fatigue, insomnia and decreased sleep quality. Moreover, shift work has deleterious effects on both work productivity and safety. In this review, we present a brief overview of the current literature on the consequences of shift work, especially focusing on attention-associated cognitive decline and related behavioral changes. We searched two electronic databases, PubMed and RISS, using key search terms related to cognitive domains, deleterious effects, and shift work. Twenty studies were eligible for the final review. The consequences of shift work can be classified into the following three categories extracted from the literature review : 1) work accidents ; 2) commuting accidents such as car accidents that occur on the way to and from work ; and 3) attendance management at work (i.e., absenteeism, tardiness, and unscheduled early departure). These cognitive and behavioral consequences of shift work were also found to be associated with sleep disorders in shift workers. Thus, improvements in the shift work system are necessary in order to enhance workers' health conditions, work productivity, and safety.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.12-25
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• 2016

The purpose of this study is providing an evaluation criteria for appropriateness of bicycle riding path considering trip purpose based on cyclist's response of importance and satisfaction. The survey presents a quantified criteria of evaluating appropriateness of the bicycle path by investigating difference of impotance and satisfaction between two purposes among 5 selected influence factors about bicycle lane and bicycle parking facility, and in case of commuting purpose, information of destination is additionally considered. All the influence factors are analyzed by Analytical Hierarchy Process (AHP) which yields importance. For the factors which have a huge difference between two purposes, evaluation criteria using a GIS Data of respondent's path and satisfaction of each factors is developed, and other factors are made it by reviewing literature. The importance analyzed by AHP and evaluation criteria can provide a path based LOS for cyclist, and this information can be improved through user's response from app or search engine in the future. and by considering individual's evaluation, it can provide individually specified information.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.445-450
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• 2012

From 2015, PM2.5 standards will be added to Korean national ambient air quality standards. To characterize PM2.5 levels in Cheonan, annual PM2.5 concentrations along with PM10 concentrations were investigated between February 2010 and January 2011 using a dust monitor. The annual PM2.5 concentration was $40.45{\mu}g/m^3$ and over the standards($25{\mu}g/m^3$). The daily average PM2.5 concentrations ranged from 2.43 to $178.84{\mu}g/m^3$, and 26% days exceeded the daily PM2.5 standard($50{\mu}g/m^3$). During the same periods, only 11% days exceeded the daily PM10 standard, showing that PM2.5 were more concerning levels than PM10. Seasonal variations showed the highest concentrations in spring and winter, and lowest concentration in summer due to heavy rain fall. Changes in PM2.5 concentrations during the day were remarkable and showed the highest concentrations in commuting periods. The results indicated that the concentrations of PM2.5 in Cheonan were at the concerning level, and mainly from the mobile sources.

• Journal of Power Electronics
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• v.11 no.4
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• pp.408-417
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• 2011

The plug-in hybrid electric vehicles (PHEVs) are specialized hybrid electric vehicles that have the potential to obtain enough energy for average daily commuting from batteries. The PHEV battery would be recharged from the power grid at home or at work and would thus allow for a reduction in the overall fuel consumption. This paper proposes an integrated power electronics interface for PHEVs, which consists of a novel Eight-Switch Inverter (ESI) and an interleaved DC/DC converter, in order to reduce the cost, the mass and the size of the power electronics unit (PEU) with high performance at any operating mode. In the proposed configuration, a novel Eight-Switch Inverter (ESI) is able to function as a bidirectional single-phase AC/DC battery charger/ vehicle to grid (V2G) and to transfer electrical energy between the DC-link (connected to the battery) and the electric traction system as DC/AC inverter. In addition, a bidirectional-interleaved DC/DC converter with dual-loop controller is proposed for interfacing the ESI to a low-voltage battery pack in order to minimize the ripple of the battery current and to improve the efficiency of the DC system with lower inductor size. To validate the performance of the proposed configuration, the indirect field-oriented control (IFOC) based on particle swarm optimization (PSO) is proposed to optimize the efficiency of the AC drive system in PHEVs. The maximum efficiency of the motor is obtained by the evaluation of optimal rotor flux at any operating point, where the PSO is applied to evaluate the optimal flux. Moreover, an improved AC/DC controller based Proportional-Resonant Control (PRC) is proposed in order to reduce the THD of the input current in charger/V2G modes. The proposed configuration is analyzed and its performance is validated using simulated results obtained in MATLAB/ SIMULINK. Furthermore, it is experimentally validated with results obtained from the prototypes that have been developed and built in the laboratory based on TMS320F2808 DSP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.822-827
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• 2019

There is a high demand for off-base dwellings around Camp Humphreys in Pyeongtaek in accordance with the USFK base relocation project, but their residential planning needs to reflect their requirements. On the other hand, no studies that examined their requirements directly have been found. This study examined the requirements of USFK stationed in Camp Humphreys to identify their requirements. In general, residential planning requires a determination of the demand-based location and size, identification of the facility elements required for the site plan, and analysis of detailed architectural planning elements required for the building plan. Among these, preference analysis of the off-base dwelling demand, location, and site planning elements were performed in this study, and the architectural planning elements were left as following studies. The analysis showed that the demand for off-base dwellings is high, rental houses are preferred, and the commuting time is the most important factor in the location. In addition, while enjoying urban convenience, the location of the foothills near nature is preferred, the importance of the orientation is low and living with Koreans is not a problem. In addition, the demands for exercise facilities in the complex are relatively high.

• Journal of the Korean association of regional geographers
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• v.8 no.4
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• pp.430-450
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• 2002

This study empirically analyses the spatial features of land use and transportation, and residential characteristics of the cases of the Sangin and Siji newly developed districts in Taegu. Before the development, the areas consisted mainly of rice paddies and fields; these areas are now filled with high-density residential complexes, with a proliferation of commerce and service functions. In Sangin, restaurants, retail services, bars and bakeries are the main developments, but Siji developed retail services, restaurants, private institutions for students, and facilities for convenience goods. While the public transportation system is oriented to CBD, the inter-districts transportation network is lacking. The residents are mainly in their 40s to 50s, with white collar jobs. They have a relatively high level of education with high income. They have migrated a relatively short distance to the district. The locational(pull) factors influencing the decision to migrate, for Sangin are transportation, the physical environment and access to the working place, but for Siji it has been the physical environment, the school group, and access to the working place. The main dissatisfaction factors for Sangin are the management fee, the school group and for Siji they are commuting, the management fee and transportation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.157-166
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• 2020

The city of Suwon has introduced a dockless bike for the first time in Korea. In this study, a questionnaire was conducted for citizens to suggest improvement through satisfaction analysis. As a result of the survey, 88 % of respondents awarded the presence of a bike, and 90 % answered positively in terms of bike policy; whereas mature civic ethics showed an low satisfaction. For the purpose of usage, approximately 75 % of users mainly used for commuting, business, shopping, and the connection with mass transit. In the result of the primary means of a trip, a private car was most preferred before operation; However, it was found that mode transition has been actively carried out. This suggests significant implications for implementing sustainable urbanism. Meanwhile, The level of satisfaction significantly differed in the field of payment method, charge, usage guidance and publicity by an occupation and age groups commonly. Satisfaction in bike maintenance was statistically differed by an occupation. Satisfaction in Rental-return and registration procedures showed differences by an age groups. The results of this study will contribute to establishment related policies and to more activate dockless shared bike.