• Journal of Korean Society of Transportation
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• v.18 no.5
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• pp.7-16
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• 2000

This paper is focused on verifying time-space repetition of the highway accident and finding the their causes and deterrents. We classify all months into several seasonal groups, develop the model for each seasonal group and analyze the results of these models for Joong-bu highway. The existence of seasonal effect is verified by the analysis or self-organizing map and the accident indices. Agglomerative hierarchical cluster analysis which is used to decide the seasonal groups in accordance with accident patterns, winter group, spring-fall group. and summer group. The accident features of winter group are that the accident rate is high but the severity rate is low. while those of summer group are that the accident rate is low but the severity rate is high. Also, the regression model which is developed to identify the accident Pattern or each seasonal group represents that the season-related factors, such as the amount of rainfall, the amount of snowfall, days of rainfall, days of snowfall etc. are strongly related to the accident pattern of evert seasonal group and among these factors the traffic volume, amount of rainfall. the amount of snowfall and days of freezing importantly affect the local accident Pattern. So, seasonal effect should be considered to the identification of high-risk road section. the development of descriptive and Predictive accident model, the resource allocation model of accident in order to make safety management plan efficient.

• Journal of Korean Society of Transportation
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• v.28 no.2
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• pp.135-150
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• 2010

This paper focuses on finding out which covenants are different among the concession agreements of Korean BTO projects and how these influenced IRR(Internal Rate of Return). That is, to figure out the political and economical determinants of IRR by analyzing the concession agreements which are the basic contract of implementing projects. As IRR is an index of profitability, so spread is an indicator of risk to collect debts. That's the reason why the analysis of spread is included. For the empirical analysis, the data of concession agreements for 75 projects and financial models are used. These 75 concession agreements are contracted from 1995 to 2008. The dependent variables are after tax nominal IRR and the spread of long term interest rates of 75 BTO projects. The independent variables are project's proceeding factors, the feasibility variables, the variables related to financial character and the variables related to covenants or the government's policy. The analysis shows that IRR has been influenced by the equity level of financial investors, the national government managed projects, the projects with minimum revenue guarantee (MRG), etc. And the equity level of financial investors, the national government managed projects and the implementation of supplementary project have an effect on spread also.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.471-476
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• 2021

Personal mobility (PM) is a new concept of transportation used by one or two people using electricity. Personal transportation aims to move quickly and conveniently over an ambiguous distance that is too close to the destination and too far to walk. In particular, as electric kickboard sharing services have become more common in recent years, they are receiving great popularity from citizens. However, it is necessary to come up with an alternative solution as it is acting as a risk not only to users but also to pedestrians and road drivers. Therefore, in order to present measures to establish and improve a safe personal mobility utilization environment, this research was conducted as follows. First, based on GPS data from shared electric kickboards, the usage status in everyday life was examined and analyzed in detail. Second, it is convenient to rent and return shared electric kickboards directly to applications regardless of time, and it is highly accessible to rent them from their location and reach their destination. Based on these findings, this study suggests that careful access to rental and return could have a more positive effect on users and pedestrians by installing a cradle in a place where there is more use than disorderly device placement and expansion.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.383-392
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• 2018

This study investigated the change of additional axial stress of rail and reaction force at bridge bearings due to the track-bridge interaction when laying CWR on non-ballasted railway bridges including truss bridges with relatively long span. According to the results of the present study, additional axial stresses of rail and reaction forces at bridge bearings showed a large increase when CWR is installed on the non-ballasted railway bridge. The additional axial stress of rail can be acceptable if sufficient lateral resistance can be obtained. However, if the reaction force increases, there is a risk of damage of the bearing or pier, and therefore, it is necessary to take measures to mitigate the reaction force. It is found that additional axial stress of rail decreases when considering the frictional resistance of the bridge movable support, but its effect on the bearing reaction force is very small. On the other hand, when the longitudinal track restraint decreases, both additional axial stress of rail and bearing reaction force are reduced to a large extent. Also, when the ZLR fastening devices are applied to the region where the additional axial stress of rail is highest, bearing reaction force as well as additional axial stress of rail greatly decreased. Therefore, the application of ZLR fastening devices with the reduction of the longitudinal track restraints is very effective for installing CWR on non-ballasted railway bridges.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.49-60
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• 2020

The number of traffic control equipment installed to prevent traffic accidents increases every year due to continuous installation by the National Police Agency and local governments. However, it is installed based on qualitative judgment rather than engineering analysis results. The purpose of this study was to present additional installations in the future by presenting the installation criteria considering the severity of accidents for each road type and calculating the appropriate number of installations. ARI indicators that can indicate the severity of traffic accidents were developed, and road types were classified through analysis of variance and cluster analysis, and accident information by road type was analyzed to derive ARI of clusters with high traffic accident severity. The ARI values required to determine the installation of equipment for each road type were presented, and 5,244 additional installation points were analyzed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.117-132
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• 2021

Due to the terrain in Korea, there are many road sections passing through mountainous areas. During the winter, there is a higher risk of traffic accidents, due to black ice caused by the lack of sunlight. Despite domestic road freezing safety measures, accidents caused by road freezing results in severe traffic accidents. Under these considerations, this study analyzed whether traffic safety signs that change in response to the external temperature help drivers recognize frozen road segments. The study was conducted through analysis of the effect of the signs on a driver's perspective. For the signs under development, out of the signs designed by experts, the sign design which received the highest visibility and effectiveness evaluation ratings from the general public was selected. The sign was implemented through Virtual Reality (VR) and installed on the right side of the road to analyze the effect on gazing and driving behavior. As a result of analyzing the driver's driving behavior, a speed reduction of about 7km/h or more was found in the sign section. Therefore, It was found that the existence of the sign had a strong relationship with the rate of the drivers' speed reduction.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.6
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• pp.375-380
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• 2022

High-speed railway bridges carry a risk of dynamic response amplification due to resonance caused by train loads, and running safety and riding comfort must therefore be reviewed through dynamic analysis in accordance with design codes. The running safety and ride comfort calculation procedure, however, is time consuming and expensive because dynamic analyses must be performed for every 10 km/h interval up to 110% of the design speed, including the critical speed for each train type. In this paper, a deep-learning-based prediction system that can predict the running safety and ride comfort in advance is proposed. The system does not use dynamic analysis but employs a deep learning algorithm. The proposed system is based on a neural network trained on the dynamic analysis results of each train and speed of the railway bridge and can predict the running safety and ride comfort according to input parameters such as train speed and bridge characteristics. To confirm the performance of the proposed system, running safety and riding comfort are predicted for a single span, straight simple beam bridge. Our results confirm that the deck vertical displacement and deck vertical acceleration for calculating running safety and riding comfort can be predicted with high accuracy.

• Journal of Platform Technology
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• v.11 no.3
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• pp.24-31
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• 2023

Recently, interest in UAM (Urban Air Mobility, UAM), which can take off and land vertically in the operation of urban air transportation systems, has been increasing. Therefore, various start-up companies are developing related technologies as eco-friendly future transportation with advanced technology. However, studies on ways to increase safety in the operation of UAM are still insignificant. In particular, efforts are more urgent to improve the safety of risks generated in the process of attempting to land in the city center by UAM equipped with autonomous driving. Accordingly, this study proposes a plan to safely land by avoiding dangerous region that interfere when autonomous UAM attempts to land in the city center. To this end, first, the latitude and longitude coordinate values of dangerous objects observed by the sense of the UAM are calculated. Based on this, we proposed to convert the coordinates of the distorted planar image from the 3D image to latitude and longitude and then use the calculated latitude and longitude to compare the pre-learned feature descriptor with the HOG (Histogram of Oriented Gradients, HOG) feature descriptor to extract the dangerous Region. Although the dangerous region could not be completely extracted, generally satisfactory results were obtained. Accordingly, the proposed research method reduces the enormous cost of selecting a take-off and landing site for UAM equipped with autonomous driving technology and contribute to basic measures to reduce risk increase safety when attempting to land in complex environments such as urban areas.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.634-643
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• 2020

Because of the continuous increase in the demand for and importance of marine space, marine exploration and survey activities are being actively conducted in Korea actively. Because the marine survey vessels used for these activities have special operational patterns depending on the purpose and probe vessels, research on maritime traffic risk is required. In this study, an attempt was made to determine the correlation of each factor with the effect of marine exploration and survey vessel operation on maritime traffic. The status of ocean exploration and survey vessels in operation in Korea was identified, as well as the special operational conditions of some of the ocean physical probes. Generally, the number of exploration and survey vessels involved per hour, total vessel length(including exploration equipment), operation, interval distance of exploration as per plan, and marine traffic conditions(traffic volume and speed) can be classified as operating factors. To compare the results of the environmental stress, a maritime traffic flow simulation based on the "ES" Model was performed with each of the identified operating factors as independent variables. The results of the analysis confirmed that the environmental stress significantly changed in the order of traffic volume, ship length and speed. In addition, it was confirmed that the environmental stress is reduced when the operation course is set at an angle with the nearby maritime traffic flow. Accordingly, it can help reduce the operator's burden if the survey vessel operator understands nearby maritime traffic conditions and reflects them in the operation method when setting the operation plan.

• 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.