• Spatial Information Research
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• v.17 no.2
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• pp.213-222
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• 2009

Finding exclusive closest pairs in road network is very useful to real applications such as, for example, finding a closest pair between a passenger and a nearby taxi in a road network. Few studies, however, have been interested in this problem. To match two close moving objects exclusively, one object must belong to only one result pair. Because moving objects in a road network change their position continuously, it is necessary to monitor closest pair results. In this paper, we propose a methodology to monitor k exclusive closest pairs via a road network. Proposed method only updates the results which are influenced by objects' movement. We evaluated the performance of the proposed method with various real road network data. The results show that our method produces better accuracy than normal batch processing methods.

• The Journal of the Korea Contents Association
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• v.13 no.7
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• pp.248-264
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• 2013

This study analyzed the differences of the person-environment fit, work stress and work satisfaction according to a demographic factors of elderly people under participation in job activities. And this study analyzed the relationship of the effects on person-environment fit, work stress and work satisfaction as well as the moderating effects of self-efficacy. The survey was conducted from February 15 to March 20, 2013 among the male taxi drivers aged 60 or older in the Seoul areas, and 358 responses were used in the data analysis. As a results, there were partially differences in the person-environment fit, work stress and work satisfaction according to a demographic factors. The person-environment fit had a negative impact on work stress, but it had a positive impact on work satisfaction. In addition, the self-efficacy had a moderating effects in the relationship of the person-organization fit and work stress.

• Spatial Information Research
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• v.7 no.2
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• pp.209-221
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• 1999

In this research, AVL-GIS(Automatic Vehicle Location System linked with Geographic Information System) system was developed using integration of core techniques of GIS engine written by Java language, GOS(Global Positioning System) and wireless telecommunication interfacing techniques. IDGPS(Inverted differential GPS) techniques was employed to estimate accurate position of mobile vehicle and to supervise their path from AVL-GLS control center system. Between mobile vehicle and AVL-GLS control center system which has spatial data analysis function, road network and rleate ddata base were connected wireless phone to communicate for position an dmessage in real time. The developed system from this research has more enhanced GIS functions rather than previous AVL oriented system which has MDT for message display and voice communication only. This system can support build-up application system such as fleet management like bus, taxi, truck, disaster and emergency and monitoring of transportation status for customer s order via web browser in filed of EC/CALS in low cost.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.265-272
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• 2019

In this paper, we selected commuting scenarios in the most congested metropolitan area in Korea, and conducted noise analysis during personal air vehicle (PAV) operation using aviation environmental design tool (AEDT)software which was developed by Federal Aviation Administration (FAA). Noise is the second important factor after safety in order to operate PAVs through concepts such as ODM (on-demand mobility) introduced by National Aeronautics and Space Administration (NASA). Noise analysis were performed by modeling low-noise ePAVs as commercial helicopters and predicted residential suitability in order to resolve problems in which accurate NPD (noise power distance) data from PAVs were not released. The application of noise reduction technology such as electric propulsion has significantly reduced noise exposure levels and has reached the conclusion that commuting with PAVs is feasible without noise problems in the metropolitan area.

• Journal of Korean Academy of Nursing
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• v.30 no.3
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• pp.659-669
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• 2000

Many patients of acute myocardial infarction showed delay time before seeking treatment although they needed immediate thrombolytic therapy once they perceived their symptoms. The objectives of this study were to identify the relationship between clinical symptoms and the delay, and to find the time spent before seeking the treatment. This study was a retrospective research. The delay time for the treatment consisted of the length of delay from symptom onset to patients' decision (T1), from patients' decision making to finding transportation (T2), and from taking transportation to the first hospital arrival(T3). The subjects were 89 patients who were admitted in the ICU and Cardiac Ward at Chonnam University Hospital with the first attack of acute myocardial infarction. Center, USA The data was collected for three months from March 1st to May 31st of 1998 through questionnaires and reviewing patients' charts: The chart information was suppled by two nurses working at the ICU and Cardiac Ward. The data was analyzed by using frequency, mean and ANOVA through the SAS program. The results of study summarized as follows: 1. Sixty two patients (69.7%) were male and twenty seven patients (30.3%) were female, the ratio of male to female was 2.3 : 1. 2. In daily life, the 70.8% of the patients felt chest pain and discomfort fatigue in 67.4%, dyspnea in 57.3%, and pain in arm, neck, and jaw in 52.8%. During the attack, 97.8% of the patients felt chest pain and discomfort dyspnea in 82.1%, pain in arm, neck, jaw in 67.4% and perspiration in 51.7%. 3. The length of time a patient spent seeking time for treatment (T1+T2+T3) was 94.6 minutes, in which the time for patients' decision making for treatment (T1) was 70.3 minutes, time for finding transportation (T2) was 8.2 minutes, and time for the transportation of the patient to the first hospital (T3) was 16.1 minutes. Time for patients' decision making to go to a hospital(T1) was 74.2% of the total time sought for treatment. 4. The differences of time sought for treatment between perceptions about the seriousness of the symptoms were significant (F= 6.5, p< .01). The more serious the heart symptoms they felt, the shorter the seeking time for treatment. 5. The differences of the time delay before treatment between the degree of the symptoms were significant (F= 2.9, p< .05). The patients with the typical chest pain and discomfort spent shorter the seeking time for treatment than those with the atypical symptoms of acute myocardial infarction. 6. The differences of transportation time to the first hospital between the types of cars that the patients used, were significant (F= 4.3, p< .01). When the patients used 119 or 129 they spent the least time (5.3 minutes) for transportation, and followed by way of an ambulance (15.6 minutes), private car (20.6 minutes), and taxi (24.8 minutes).

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.195-203
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• 2009

This research wished to risk type and examine closely driver special quality and relation of traffic accidents by occurrence type of traffic accidents and traffic accidents seriousness examine closely relation with Severity. Fractionate traffic accidents type by eight, and driver's special quality for risk group's classification did to distinction of sex, vehicle type, age etc. analyzed relation with injury degree adding belt used putting on availability for security the objectivity with wave. Used log-Linear model and Logit model for analysis of category data. A head-on collision and overtaking accident, right-turn accident are high injury or death accident and possibility to associate in relation with accident type and seriousness degree. In risk group analysis The age less than 20 years in motor-cycle driver, taxi driver in 41 years to 50 years old are very dangerous. The woman also was construed to the more risk group than man from when related to car, mini-bus, goods vehicle etc. Therefore, traffic safety education and Enforcement for risk group that way that can reduce accident that produce to reduce a loss of lives at traffic accidents appearance a head-on collision and overtaking accidents, right-turn accidents should be studied and as traffic accidents weakness class may have to be solidified.

• Journal of Korean Society of Transportation
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• v.32 no.2
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• pp.83-92
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• 2014

Weather condition is one of the crucial factors affecting travelers' mode choice. Nevertheless, there are numerous indefinite traffic phenomena under various weather conditions. This study was conducted to verify the hypothesis that transit riderships decrease as precipitation increases. To clarify the relationship between precipitation and transit ridership, a seemingly unrelated regression model was employed with data such as daily precipitation and daily transit riderships of 3 transit modes (bus, metro, and shuttle bus) collected in Busan for recent 24 months. The estimation results show that transit riderships decreased as the daily precipitation increased when the daily precipitation is greater or equal to 10mm/day (0.169%, 0.101%, and 0.172% reduction in bus, metro, and shuttle bus riderships, respectively, when the daily precipitation increased by 1mm). When comparing the impact of precipitation on transit riderships by modes using a cross-equation parameter restriction test, the decrease in metro ridership is relatively insensitive to the change in precipitation. However, the negative coefficient of precipitation in the metro ridership estimation model indicates that the transit users in Busan may alter their mode to taxi or automobile and/or may give up the trip itself in bad weather condition.

• The Journal of Society for e-Business Studies
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• v.21 no.4
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• pp.137-150
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• 2016

A variety of O2O (Online to Offline) services such as Uber, Airbnb, and KakaoTaxi that create new values by connecting offline and online have emerged in the world. O2O services support the convenience of online services and the real-life capability of offline services simultaneously. Thanks to the development of ICTs such as mobility, IoT (Internet of Things), Fin-tech, and big data technologies, the market size of O2O industry is growing very rapidly. This paper reviews various O2O services and industry trends in Korea. In addition, important issues on O2O services and industry promotion are reviewed and presented. Specifically, legislative issues regulating the O2O industry in Korea, interest conflicts between new O2O platform providers and existing traditional offline service providers, current technology infrastructures for O2O services, and negative or side effects of O2O services are reviewed and summarized. Finally, comprehensive policy directions are proposed based on these reviewed issues. It is expected that the proposed policy directions would be adopted by the government and this research could consequently contribute to strengthening the competitiveness of the O2O industry in Korea.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.442-454
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• 2016

Recently, due to the increment of national income and the living standard of citizens, the leasure business has been dramatically expanded. Among the business, inland water activities such as cruise tour or water taxi have drawn attention from the people. As more people come for a new pleasure, the frequency and the number of services continues to rise yet the safety of people values less recently. In fact, the number of relating accidents also has risen accordingly. In order to prevent such accidents in inland waters, the vessels' real time voyage data, the advanced warning system and the emergency rescuing system are required. In this paper, we have developed navigation guiding application for safety of passengers and vessels in inland waters. Navigation guiding applications not only provide Inland Electronic Navigational Chart(IENC) and vessel information but also allows communication between traffic service center and nearby vessels in case of an emergency situation. In order to implement Navigation guiding applications, developing Inland Electronic Navigational Chart was inevitable. Therefore, IENC of Han River, has developed based on measuring the water depth using multi-beam echo sounder system.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.505-511
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• 2018

Purpose : This study investigated the visual functions of drivers aged over 65 year olds and drivers aged 50~65 year olds. In addition, difference of visual functions between professional drivers and normal drivers were investigated. Methods : Forty Driver aged over 65 year olds and 67 drivers aged less than 67 year olds were participated. All participants had more than 5 years of driving experiences and had no ocular pathology. Demographic data(gender, job, age, body condition) and visual functions such as contrast sensitivity(CS), stereopsis, glare recovery time and discomfort glare index were measured. Results : Constrast sensivity under photopic condition was higher with bus driver group. In addition, difference of CS at 12cpd and 18cpd were signifcantly different between normal drivers(1.57) and bus drivers(1.70) (p<0.05). There was no significant difference for glare recovery time, despite of trend of longer recovery time with age. Discomfort glare index was significantly different that normal drivers with more than 65 year olds had 3, taxi and truck driver presented almost 5 index score (p<0.05). Conclusion : Analysis of visual function of elderly drivers, it was confirmed that their visual functions decreased with age. Therefore, visual function tests such as CS, discomfort glare index and stereopsis in addition to current available test may need to be considered for drivers aged over 65.