• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.32-39
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• 2006

5.8GHz DSRC(Dedicated Short Range Communications) is a short to medium range communications service that supports both public safety and private operations in roadside to vehicle and vehicle communication. However the 5.8GHz frequency may cause the shadowing effect or communication blocking problem when there is an obstacle or another vehicle between RSE (Road Side Equipment) and OBE (On Board Equipment). In this paper, to solve this problem of the 5.8GHz DSRC, we propose a relay protocol based on the standard of DSRC radio communication between RSE and OBE in the 5.8GHz band made by TTA (Telecommunication Technology Association). By using the proposed relay protocol to DSRC system and intervehicle communication, we also consider a fixed relay protocol and mobile relay protocol. We expect to apply this relay protocol for the DSRC intervehicle communication and video communication between drivers and safe distance among vehicles in the near future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2604-2611
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• 2013

The Personal Rapid Transit(PRT) system has been highly interested in future transportation developments due to its on-demand and optimized door-to-door transport capability. However, the major impediments to the commercialization of PRT are the high cost for construction of infrastructures as opposed to the small transport capacity and difficulty in defining the role of PRT in building a balanced transportation system. In this study, the vertical transfer device for the PRT vehicle is developed to provide more flexible and better compatible urban mobility services between means of transportation, which is expected to meet particular demands in a particular environment. This apparatus was initially designed based on the basis of vertical circulating conveyors with steel chains, which is frequently used in logistics. Its advantages are capable of the non-stop loading and reduced head-way time. Most importantly, it was intensified by the additional idea to ensure the stable and reliable transfer of the PRT vehicle fully loaded with passengers. The 1/10-scale prototype was successfully tested to demonstrate a fundamental mechanism of vertical transfer and identify unexpected user requirements prior to a real manufacturing process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.53-59
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• 2019

To reduce the vibrations and shocks during the cargo transportation of high value-added goods, the vibration history was measured on the truck transportation section (Asan-Uiwang) and the freight train transportation section (Uiwang-Pusan). The internal vibrations of the container were obtained by attaching acceleration sensors in three axis directions (longitudinal, lateral. and vertical directions) on the front and rear bogies. The rail vibration profile (0.29Grms) proposed in ASTM D-4169 was approximately 50% higher than the truck vibration profile (0.54Grms). The overall vibration was 16% and 33 % lower in the longitudinal and transverse directions, respectively, compared to the ASTM truck transport vibration profile. On the other hand, the vertical vibration measurement history partially exceeded the ASTM truck transport vibration profile over the range, 4 - 15Hz, and over 60Hz. The vibration measurement history of the cargo train was similar to that of the road. The longitudinal and lateral vibration history was lower than the ASTM D-4169 rail vibration profile, while the vertical history was over 30Hz.

• Journal of Preventive Medicine and Public Health
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• v.1 no.1
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• pp.1-8
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• 1968

This paper describes the incidence of transport accident for the period, 1955-1965. Transport accidents were classified into three categories, viz. railway(WHO Classification of Diseases, E-802), watercraft (E 550-E 858) and motor vehicle accidents(E810-E835, E840-E841, E844-E845). Crude data on the subject were collected from the various souces of Government Statistical Books including Statistical Year Books edited by the Central Office of Economic Planning Board, Annual Police Reports by the Ministry of Home Affairs, and the national and local associations for road traffic safety. From the data incidence and mortality rates by year, month and local province were computed and other variables relevant to the epidemiology of accidents were observed. The following summary could be drawn: 1. Death rates due to transport accidents per 100,000 population were 12.3 for 1955 and 9.7 for 1965. The incidence of injury due to the same cause were 34.0 for 1955 and 35.9 for 1965. 2. Death rates by transportation vehicle showed 9.0 due to motor vehicle accidents, 1.7 due to water-crafts, and 1.6 due to railway trains for 1955. In 1965 death rates were 6.0 due to motor vehicles, 1.2 to water-crafts and 2.4 to railway. 3. Seasonal distribution of transport accidents revealed that car accidents occur more frequently in spring and fall fall seasons while ship accidents do in winter and train accidents more in summer. 4. Both car and ship accidents slightly decreased during the past decade, 1955-1965, whereas the accidents of railway trains showed a tendency of increase. 5. Although the survey on railway accidents excluded the injuries of passengers or railway employees corresponding to WHO classification of diseases, E 801, due to inaccuracy of data, it is roughly estimated that the same number of casualities as the incidence among pedestrians or any other than passengers or employees assumed to be at work(E 802).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.827-835
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• 2017

With the rapid progress of ageing several issues concurrently occur, and one important social issue that must be resolved is accidents involving Elderly drivers. Efforts to reduce the frequency of such accidents is a must in order to be prepared to face a superaged society. Currently people aged 65 or older are prescribed as an "Elderly person." Therefore, various studies concerning accidents involving Elderly drivers apply this age criteria to separate regular drivers and Elderly drivers. However, there is no criteria to practically discern Elderly drivers with certain physical features as vulnerable road users based on a level of acceptable accuracy. Therefore, this studies intends to compare the possibility of accidents by age group of Elderly drivers by correlation analysis to analyze the accident characteristics by age group. Results showed that for drivers aged 75 and older, their influence on major accident characteristics by vehicle type increased with higher age groups. In particular, passenger cars had a relatively low accident frequency rate for drivers aged between 70 and 80, but for drivers aged 75 to 84, they had higher influence on accidents for the same vehicle type. This demonstrates that as ageing progresses and the average life expectancy increases, the age span of elders continues to increase, meaning that characteristics differ by age group among the aged. This study confirmed that the influence on the possibility of accidents differs by age group among the aged.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.41-51
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• 2002

As Advanced Traveler Information System(ATIS) is the kernel of the Intelligent Transportation System, it is very important how to manage data from traffic information collectors on a road and have at borough grip of the travel time's change quickly and exactly for doing its part. Link travel time can be obtained by two method. One is measured by area detection systems and the other is estimated by point detection systems. Measured travel time by area detection systems has the limitation for real time information because it Is calculated by the probe which has already passed through the link. Estimated travel time by point detection systems is calculated by the data on the same time of each. section, this is, it use the characteristic of the various cars of each section to estimate travel time. For this reason, it has the difference with real travel time. In this study, Artificial Neural Networks is used for estimating link travel time concerned about the relationship with vehicle detector data and link travel time. The method of estimating link travel time are classified according to the kind of input data and the Absolute value of error between the estimated and the real are distributed within 5$\~$15minute over 90 percent with the result of testing the method using the vehicle detector data and AVI data of Namsan Tunnel $\#$1. It also reduces Time lag of the information offered time and draws late delay generation and dissolution.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.111-117
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• 2017

The purpose of forecasting the traffic accident is to reduce the traffic accident. Therefore, the goal of this study is to provide severity of the accident by Forecasting of Probability of Accident. In Korea, accident data are distributed to the public via internet that includes numbers of accident and fatality as well. And crude level of accident severity in accordance with weather information for metropolitan city level are available by weekly. However, It can not reflect personal needs at specific origin of the travel for a certain traveller. This study aims to consider 68 major intersections with precipitation data, and eventually introduces link based accident severity. In estimating the accident severity both dynamic data such as drivers' characteristics, driving conditions and static data such as geometry of road, intersection characteristics are considered. Also, we identifies accident severity according to the accident type - 'vehicle to vehicle,' 'vehicle to person.' Finally, the outcomes of this study suggests taylor-made accident severity information for a specific traveller for a certain route.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.1-6
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• 2019

The objective of this study was to investigate performance characteristics of thermal management system(TMS) in a fuel cell electric vehicle with 100kW Fuel Cell(FC) system. In order to build up analytic modelling for TMS, each component was installed and tested under various operating conditions, such as water pump, radiator, 3-Way valve, COD heater, and FC stack etc. and as the results of them, correlations reflecting component's characteristics with flow rate, air velocity were developed. Developed analytic modelling was carried out under various operating conditions on the road. To verify modelling's accuracy, after prediction for optimum coolant flow rate was fulfilled under certain operating conditions, such as FC system, water pump speed, opening of 3-way valve, and pipe resistance, analytic and experimental values were compared and good agreement was shown. In order to predict cold-start operating performance for analytic modelling, coolant temperature variation was analyzed with $-20^{\circ}C$ ambient temperature and duration was predicted to rise in optimum temperature for FC. Because there is appropriate temperature difference between inlet and outlet of FC stack to operate FC system properly, related analysis was performed with respect to power consumption for TMS and heat rejection rate and performance map was depicted along with FC operating conditions.

• Journal of Practical Engineering Education
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• v.14 no.3
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• pp.593-600
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• 2022

Various sensors such as lidar, radar, and camera are fused and used in autonomous vehicles. Rider and radar sensors are difficult to popularize because they are expensive equipment. In order to popularize autonomous vehicles, research that can replace expensive equipment is continuously being conducted. In this paper, we use a single camera that is inexpensive and can be easily mounted. We propose a method for detecting the wheels and adjacent lanes of a front-side vehicle of a driving vehicle and estimating distances. Our proposed method detects lanes and wheels from frame images after frame extraction via input images. In addition, the distance is measured and compared with the actual distance measured in the actual road environment. The distance could be calculated relatively accurately within the error range of ± 3 cm. Through this, it is expected that the camera can be used as an alternative means when the cost of autonomous vehicles is reduced or when the lidar or radar sensor fails.

• Korean Journal of Environment and Ecology
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• v.32 no.3
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• pp.323-331
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• 2018

This study was conducted to examine the effects of constructing streetside urban forests on particulate matter (PM) content in pedestrian paths and open spaces created between the main streets and buildings in a high-rise, high-density urban area. The study site is a 70m-wide open space between Busan City Hall and Jungang-street in Busan, Korea. The results showed that the density of PM differences between the open space and the adjacent main street were small in regions without linear trees and shrub rows during both the weekdays and weekend. On the other hand, the areas with linear trees and shrub rows were found to have significantly higher concentrations of PM compared to the roadway. In particular, sections with linear trees and shrub rows had higher PM levels both on roads and in adjacent open space, indicating that the composition of linear trees and shrub rows increased the concentration of PM in the off-street open space in areas with wide space between the roadway and building. The impact was more significant in the open space than the roadway. This phenomenon can be explained by the fact that PM generated by vehicles flows through the roadside shrubs by rapid wind flow but does not disperse widely in the pedestrian paths where the wind flow was reduced. In this study, we found that the roadside tree and shrub walls slowed the flow of wind, causing vehicle-emitted PM to accumulate if a wide open space was created between the road and building, resulting in higher concentration of PM in the open space. We confirmed that the distance between the road and building was a critical factor for constructing linear trees and shrub rows to reduce PM generated by vehicle traffic.