• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.897-905
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• 2015

This research suggested the traffic signal calculation model of active transit signal priority using a shockwave model. Using this signal priority timing optimization model, the shockwave area is computed under the condition of Early Green and Green Extension among active transit signal priority techniques. This study suggested the speed estimation method of backward shockwave using average travel time and intersection passing time. A shockwave area change is calculated according to signal timing change of transit signal priority. Moreover, this signal timing calculation model could determine the optimal signal priority timings to minimize intersection delay of general vehicles. A micro simulation analysis using VISSIM and its user application model ComInterface was applied. This study checked that this model could calculate the signal timings to minimize intersection delay considering saturation condition of traffic flow. In case studies using an isolated intersection, this study checked that this model could improve general vehicle delay of more over ten percentage as compared with equality reduction strategy of non-priority phases. Recently, transit priority facilities are spreading such as tram, BRT and median bus lane in Korea. This research has an important significance in that the proposed priority model is a new methodology that improve operation efficiency of signal intersection.

• Science of Emotion and Sensibility
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• v.17 no.4
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• pp.29-40
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• 2014

The positive relationship between older driver's mobility and life satisfaction is well established(e. g., Collins, 2008). The present study showed that this relationship can be changed by older drivers' motivation, aspects of mobility, and affectivity. Specifically, this study examined whether aspects of mobility(amount of driving measured by travel distance and time: 'AD' or amount of driving for social activity: 'DSA') can be differed as a function of approach/avoidance motivation(measured by BIS/BAS scale, Carver et al., 1994) and positive/negative affect(PA/NA; measured by SPANAS, Diener et al., 2009) mediate the relationship between the aspects of mobility and life satisfaction(measured by SWLS, Diener et al., 1985). Self-reported scores of the variables of 132 older drivers(ages of over 65) were analyzed using correlation analysis and path analysis. The results can be summarized as followings. First, the older driver's BAS was found to be positively related to DSA, but BIS was negatively to AD. In particular, DSA positively mediated the relationship between BAS and PA. Second, PA, in turn, positively mediated the relationship between DSA and life satisfaction. The results can provide useful insights to understand the relationship between older driver's driving property, motivation, affectivity and life satisfaction.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.19-31
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• 2007

When estimating the benefits from an investment project in the transportation sector, errors caused by many factors may exist. This study focuses on user equilibrium traffic assignment methods and stopping criteria. According to previous studies, when using a user equilibrium assignment model, the benefits of travel time savings can be effected by the relative gap value. As the stopping criteria decreases, the time needed for traffic assignment increases, so that lowering the criteria cannot be the best solution. Therefore, an effort is necessary to reduce this change rate and thus improve reliability. This paper considers three methods: reducing the links subject to benefit calculation, extracting sub-area O/D tables and networks, and applying the mean value of successive traffic assignment results. The results of the analysis show that the method using the mean value of five results is more proper than the other methods. Using the sub-area analysis method, if the study area is small the benefits of a project might be over- or under-estimated. This paper used a nationwide O/D table and network at peak time as a case study. The resulting patterns can differ according to basic data to be used in analysis. So further analysis using the data from metropolitan areas are needed.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.317-325
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• 2010

This study aims to deduct the extensive improvement types of leisure activities of private security agents using PPA technique and to examine the influence of leisure constraint on the index of participation. Through this process, this study consequently will draw the priority list of investment on the policy for improving the welfare status of private security agents. In this study, judgement sampling was applied to 6 security agencies located in Seoul, 2010, and 267 cases were used in the final analysis. Collected data went through factor analysis, reliability analysis, paired t test, PPA analysis, and regression analysis by using SPSSWIN 17.0. The conclusions were drawn as follows. In regard to the reliability, Cronbach's $\alpha$ was over .768. First, there was a difference between the preference rate and the participation rate which are the participation index of the private security agents' leisure activities. concentrate here in leisure types turned out to be fitness activities, walking/jogging, tourism, a day-long travel, and keep up the cood work in leisure types are movies, domestic tourist attractions, dating, eating out, personal relationship, watching sports, reading, karaoke, TV video watching, drinking etc. low priority in leisure types are water sports, hiking, biking, soccer, photography, ball games, sky sports, playing go/janggi, inline skates, and cooking. Second, the leisure constraint affects the participation index of leisure activities. As the personal constraint, and surrounding conscious constraint which are the subordinate factors of the leisure constraint get bigger, the participation index of favored leisure activities become lower. In contrast, when the difficulties such as structural constraint, time and economical constraint are overcome, participation index of leisure activities go on the rise.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.17-24
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• 2008

Traffic accident forecasting model has been developed steadily to understand factors affecting traffic accidents and to reduce them. In Korea, the length of highways is over 3,000km, and it is within the top ten in the world. However, the number of accidents-per-one kilometer highway is higher than any other countries. The rapid increase of travel demand and transportation infrastructures since 1980's may influence on the high rates of traffic accident. Accident severity is one of the important indices as well as the rate of accident and factors such as road geometric conditions, driver characteristics and type of vehicles may be related to traffic accident severity. However, since all these factors are interacted complicatedly, the interactions are not easily identified. A structural equations model is adopted to capture the complex relationships among variables. In the model estimation, we use 2,880 accident data on highways in Korea. The SEM with several factors mentioned above as endogenous and exogenous variables shows that they have complex and strong relationships.

• Journal of Korean Society of Transportation
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• v.36 no.1
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• pp.38-50
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• 2018

Emerging automated driving environments will lead to a mixed traffic flow depending on the interaction between automated vehicles (AVs) and manually driven vehicles (MVs) because the market penetration rate (MPR) of AVs will gradually increase over time. Understanding the characteristics of mixed traffic conditions, and developing a method to control both AV and MV maneuverings smoothly is a backbone of the traffic management in the era of automated driving. To facilitate smooth vehicle interactions, the maneuvering of AVs should be properly determined by various traffic and road conditions, which motivates this study. This study investigated whether the aggressiveness of AV maneuvering, defined as automated driving aggressiveness (ADA), affect the performance of mixed traffic flow. VISSIM microscopic simulation experiments were conducted to derive proper ADAs for satisfying both the traffic safety and the operational efficiency. Traffic conflict rates and average travel speeds were used as indicators for the performance of safety and operations. While conducting simulations, level of service(LOS) and market penetration rate(MPR) of AVs were also taken into considerations. Results implies that an effective guideline to manage the ADA under various traffic and road conditions needs to be developed from the perspective of traffic operations to optimize traffic performances.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.249-255
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• 2017

The domestic tourism industry mostly relies on quantitative surveys for customer satisfaction. However, customer participation of the questionnaires is extremely low and the improvement of the dissatisfactory factors is not being performed promptly. In this paper, we propose a new topic map system and prove its empirical effectiveness to improve the accuracy of customer feedback information and the efficiency of the analysis process. The topic map system is a system for analyzing large amounts of customer feedback data in real time. It uses text mining and ontology techniques by integrating data collected over a certain period from real-time SNS and quantitative data obtained from existing survey systems. The effect after improving the analyzed factors of dissatisfaction is also a new and innovative evaluation system for monitoring customer satisfaction in real time. The classification based on this integrated data is a classification system that is specific to the product or the customer. According to this classification, it is possible to measure the effect of the recognition and improvement of the complaint factor in real time on the topic map system. This provides a sophisticated prioritization of the improvement factors and enables customer satisfaction quality control as a PDCA feedback system. In addition, the survey period and costs are greatly shortened, and responses can be more precise to the existing survey method. As a practical application, this system is applied to the largest H travel agency in Korea to prove the accuracy and efficiency of the proposed system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.77-82
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• 2012

To share the lanes with conventional vehicles, traffic operation strategy is needed for NEV (Neighborhood Electric Vehicle). Because NEV cannot accelerate sharply as fast as common car include gasoline, diesel and LPG cars, they may interrupt traffic conditions and make traffic delay. After green lights turn on, all vehicles run through the street including NEV, but NEV have a maximum speed which is 50km/h. It can be an obstacle for following vehicles and will make traffic delay of the intersection. In this reason, we need to organize traffic systems like queue jump with priority traffic signal. To analyze the necessity for NEV road operations, we simulate three scenarios in congested and non-congested conditions. First is that we examine the condition which is mixed NEV and cars on the road, the second one is that we set up lane only NEV can accepted in simulation and last one is making queue jump lane and providing priority signal for NEV. In conclusion, we can conclude that making lane only for NEV is effective to improve travel speed when rate of NEVs is over 20%. Also queue jump lane and priority signal cannot make good effect to intersection delay and average speed.

• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.15-21
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• 1996

Effects of acid deposition on the acidification of surface water over a short term period were studied during June~October, 1995. A reservoir located in Chunchon, Kangwondo was selected for this study because this reservoir had received little man-made pollutants. Geological survey within the study area was carried out and the pH of a small and shallow stream flowing from the mountain valley down to the reservoir was monitored. Rainfall was measured by using a rain gauge and the precipitation was collected by automatic precipitation sampler. During the study period, rain pH was in the range of 3.81~5.77 with an average of 4.8. The EC was in the range of 5~189$\mu$S/cm with an average of 10.6$\mu$S/cm. ionic composition of the rainfall showed that of the anions, deposition of ${SO_4}^{2-}$, was highest with 3,119.7 kg/$\textrm{km}^2$, and it was $NH^{4+}$ with 1,053.2kg/$\textrm{km}^2$ for cations. The surface water pHs were maintained neutral or weak basic representing little evidence of acidification regardless of the acidic rainfall pH. Every time of sampling, however, the pHs exhibited increasing tendency as elevation of measuring site of the stream became lowered, which indicated the impacts of acid-base reactions by acidic or basic substances during travel of water downstream. This result suggested the necessity of further research to determine the respective buffering capacity of soil and underlying rocks.

• Asian Journal for Public Opinion Research
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• v.5 no.3
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• pp.228-249
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• 2018

In 2015, the population of elderly people in Thailand was 16% of the total population and is predicted to be over 20% by 2021 and nearly 28% by 2031. The increase of the elderly population in Thailand has also increased the proportion of dependent elderly people, and caring for them poses many challenges for both families and the government. This descriptive method research aimed to survey the health status of dependent older people in the rural community of Lampang province in northern Thailand. The participants consisted of 62 older people and 62 primary family caregivers from Hong Ha Health Promoting Hospital, Lampang, Thailand (totaling 124 people). The researchers assessed the health status of older people and their activities of daily living (ADL). In addition, researchers assessed the health status and stress of caregivers. All the participants were interviewed about their experiences with caregiving. The results showed that most of the older respondents were female with an average age of 78.15 years. Based on the ADL assessment, 50 of the 62 older persons were homebound while the rest were bedridden. The majority of older people had chronic or long-term conditions that required hospitalization from time to time. Their frequent health problems included oral disorders such as tooth decay or caries/gum disease/no teeth, reduced sight, psychological disorders, knee pain and risk of falling, low BMI, risk of malnutrition, and urinary leakage and incontinence (58.06%, 66.13%, 62.90%, 70.97%, 38.71%, 66.13%, and 37.10%, respectively). Usual care provided by the family members included personal hygiene care, food preparation and feeding, medication management, housekeeping and organizing necessary equipment, supply of needed equipment, prevention of falls, helping with travel for medical checkups and treatment, and providing companionship. Families experienced shortages of medical supplies, daily use equipment, lack of employment, inadequate income, and difficulty accessing health care services due to lack of transportation. Some caregivers experienced caregiving stress related to a lack of social interactions as well as routine caregiving activities. Families need different types of support in order to promote the well-being of older people and caregivers. This highlights the need for a community participation model for the care of older people in order to reflect sustainable long-term outcomes.