• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.26-34
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• 2014

This study focuses on development of a risk level evaluation model for the intersection dilemma zone based on vehicle speed distribution approaching the intersection. The study results show that dilemma zone exists for all approaches selected for the study because the values of amber time have not been properly set, and that re-optimized values significantly reduce the dilemma zone risk level. It is also found that when normal distribution is assumed for vehicle approach speed the risk values similar to those for actual speed distributions can be obtained. When the risk level is found to be high, the amber time must be adjusted to reduce the length of the dilemma zone, or speed calming measures must be introduced so that vehicle speed be maintained under the speed value used when determining the amber time.

• Journal of Information Processing Systems
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• v.16 no.5
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• pp.1064-1073
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• 2020

The general situation of system composition and safety management of high-speed railway terminal is investigated and a comprehensive evaluation index system of operational security is established on the basis of railway laws and regulations and previous research results to evaluate the operational security management of the high-speed railway terminal objectively and scientifically. Index weight is determined by introducing interval eigenvalue method (IEM), which aims to reduce the dependence of judgment matrix on consistency test and improve judgment accuracy. Operational security status of a high-speed railway terminal in northwest China is analyzed using the traditional model of fuzzy comprehensive evaluation, and a general technique idea and references for the operational security evaluation of the high-speed railway terminal are provided. IEM is introduced to determine the weight of each index, overcomes shortcomings of traditional analytic hierarchy process (AHP) method, and improves the accuracy and scientificity of the comprehensive evaluation. Risk factors, such as terrorist attacks, bad weather, and building fires, are intentionally avoided in the selection of evaluation indicators due to the complexity of risk factors in the operation of high-speed railway passenger stations and limitation of the length of the paper. However, such risk factors should be considered in the follow-up studies.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.102-113
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• 2023

With the increasing use of E-scooters, there is an urgent need for research into their driving risks because of the rising number of related accidents. Existing theoretical analysis methods are primarily vehicle-centered and do not adequately reflect the lightweight and compact characteristics of E-scooters. This study was conducted on real roads to analyze the risk and stable speeds of drivers on longitudinal slopes, considering the unique attributes of E-scooters. The risk speed on slopes was, on average, 21 km/h, with the initial risk speed decreasing as the slope became steeper. The stable speed was determined to be an average of 17 km/h, except on slopes of 1-2%, which presented a relatively low risk. These results are expected to contribute to the academic foundation for policies aimed at reducing the top speed of personal mobility, as is currently being promoted in Korea.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.1
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• pp.115-129
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• 2003

This paper Is concerned with a new techno-economic model Ing of ATM based h19h-speed networks. Coupled with advances of technology, the rapid development of new telecommunication services significantly increases the magnitude of risk in making an Investment decision. Naturally, the success of techno-economic modeling depends on how effectively we manage underlying risk factors such as cost and technology To deal with risk factors, we need to rely on modern decision and risk analysis while Implementing mathematical optimization for solving a complex capacity expansion problem of telecommunication systems during the planning period. We provide a case study that will enhance our understanding of the techno-economic analysis for emerging telecommunication systems.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.6
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• pp.1007-1019
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• 2015

The determination of the required seawall height is usually based on the combination of wind speed (or wave height) and still water level according to a specified return period, e.g., 50-year return period wind speed and 50-year return period still water level. In reality, the two variables are be partially correlated. This may be lead to over-design (costs) of seawall structures. The above-mentioned return period for the design of a seawall depends on economy, society and natural environment in the region. This means a specified risk level of overtopping or damage of a seawall structure is usually allowed. The aim of this paper is to present a conditional risk probability-based seawall height design method which incorporates the correlation of the two variables. For purposes of demonstration, the wind speeds and water levels collected from Jiangsu of China are analyzed. The results show this method can improve seawall height design accuracy.

• The Korean Journal of Emergency Medical Services
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• v.4 no.1
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• pp.95-100
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• 2000

This is a study to evaluate the effects of the safety of ambulance driving and traffic accidents and to provide statistic information for the various factors to reduce the ambulance traffic accidents. The major instruments of this study were Korean Self-Analysis Driver Opinionnaire. This Questionnaire contains 8 items which measure drivers' opinions or attitudes: driving courtesy, emotion, traffic law, speed, vehicle condition, the use of drugs, high-risk behavior, human factors. The total of 145 divers were investigated ambulance drivers in Taejon City and others(6 City) from 2000. 5. July to 2000. 11. July. The data were analyzed by the path analysis - with SPSS and AMOS package program. The result are as follows : 1. It have suggested that risk factors of ambulance traffic accident much affected with emotion and speed control on safety ambulance driving(Y(Accident) = $0.88{\times}1$(Emotion Control) + $0.92{\times}2$(Speed) - $0.46{\times}3$(Traffic Law)+E). 2. It have suggested that risk factors of ambulance traffic accident much affected with emotion and speed control on safety ambulance driving(Y(Accident) = $0.398{\times}1$(Emotion Control) + $0.500{\times}2$(Speed) - $0.263{\times}3$(Traffic Law)+E) by coefficiecial structural analysis.

• Wind and Structures
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• v.14 no.1
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• pp.71-80
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• 2011

This study presents a decision making process for installation of wind barrier which is used to reduce the wind speed applied to running vehicles on expressway. To determine whether it is needed to install wind barrier or not, cost and benefit from wind barrier are calculated during lifetime. In obtaining car accidental risk, probabilistic distribution of wind speed, daily traffic volume, mixture ratio in the volume, and duration time for wind speed range are considered. It is recommended to install wind barrier if benefit from the barrier installation exceed construction cost. In the numerical examples, case studies were shown for risk and benefit calculation and main risky regions on Korean highway were all evaluated to identify the number of installation sites.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.395-403
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• 2017

An efficient evaluation method for the probability of a tornado missile strike without using the Monte Carlo method is proposed in this paper. A major part of the proposed probability evaluation is based on numerical results computed using an in-house code, Tornado-borne missile analysis code, which enables us to evaluate the liftoff and flight behaviors of unconstrained objects on the ground driven by a tornado. Using the Tornado-borne missile analysis code, we can obtain a stochastic correlation between local wind speed and flight distance of each object, and this stochastic correlation is used to evaluate the conditional strike probability, $Q_V(r)$, of a missile located at position r, where the local wind speed is V. In contrast, the annual exceedance probability of local wind speed, which can be computed using a tornado hazard analysis code, is used to derive the probability density function, p(V). Then, we finally obtain the annual probability of tornado missile strike on a structure with the convolutional integration of product of $Q_V(r)$ and p(V) over V. The evaluation method is applied to a simple problem to qualitatively confirm the validity, and to quantitatively verify the results for two extreme cases in which an object is located just in the vicinity of or far away from the structure.

• Journal of the Ergonomics Society of Korea
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• v.34 no.5
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• pp.363-375
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• 2015

Objective: This study aims to recognize the risk of current traffic systems and to investigate a method to decrease risk by doing exercise using an elastic-band and cognitive rehabilitation. Background: The existing traffic system usually focuses on the ordinary citizens, which may not be appropriate to the elderly. It may affect the cognition and walking speed of the elderly. This study tries to examine whether cognition and muscle training is appropriate to improve their vulnerability. Therefore this study will provide human ergonomics - based basic data in relation to the elderly to identify the risk of current signal system and to mitigate the risk. Method: A total of 30 elderly participants were divided into two groups: experimental and control groups. Experimental group (n=15) was trained to strengthen their muscles and to promote cognition, whereas control group (n=15) was not. The training was conducted twice a week for three weeks. To strengthen muscles, a yellow colored elastic-band was used, and a computer program for cognitive rehabilitation was used to develop cognition. In the experimental group, there were significant differences between pre and post exercises However, the control group didn't show any significant difference. The increase in cognition and walking speed was found in the experimental group, whereas there were no differences in the control group. Statistically there was no significant difference between the two groups. Results: The results of this study show that the exercise program using the elastic-band gave a positive effect on gait training thanks to the development of muscle power and balance. Conclusion: This study did not show any statistical difference or significant differences between the two groups, since time was restricted, we believe. Application: The results of the walking speed will help to prevent traffic collision.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.2
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• pp.188-198
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• 2013

In constructing a collision avoidance system, it is important to determine the time for starting collision avoidance maneuver. Many researchers have attempted to formulate various indices by applying a range of techniques. Among these indices, collision risk obtained by combining Distance to the Closest Point of Approach (DCPA) and Time to the Closest Point of Approach (TCPA) information with fuzzy theory is mostly used. However, the collision risk has a limit, in that membership functions of DCPA and TCPA are empirically determined. In addition, the collision risk is not able to consider several critical collision conditions where the target ship fails to take appropriate actions. It is therefore necessary to design a new concept based on logical approaches. In this paper, a collision ratio is proposed, which is the expected ratio of unavoidable paths to total paths under suitably characterized operation conditions. Total paths are determined by considering categories such as action space and methodology of avoidance. The International Regulations for Preventing Collisions at Sea (1972) and collision avoidance rules (2001) are considered to solve the slower ship's dilemma. Different methods which are based on a constant speed model and simulated speed model are used to calculate the relative positions between own ship and target ship. In the simulated speed model, fuzzy control is applied to determination of command rudder angle. At various encounter situations, the time histories of the collision ratio based on the simulated speed model are compared with those based on the constant speed model.