• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2055-2061
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• 2022

In the event of a short-circuit accident on a 4.16 kV non-safety bus, the voltage is temporarily lowered as backflow occurs on the safety bus. In such cases, the undervoltage relay of the safety bus shall not pick up the undervoltage so as not to interfere with the operation of the safety motors. The aim of this study is to develop an adaptive undervoltage protection scheme for the 4.16 kV safety bus considering the faults on the 13.8 kV and 4.16 kV non-safety buses connected to secondary windings of the three winding transformers, UAT and SAT. The result of this study will be the adaptive undervoltage protection scheme for the safety bus of nuclear power plants satisfying functional requirements of the safety related medium voltage motors. The adaptive undervoltage protection scheme can be implemented into an integrated digital protective relay to make user friendly and reliable protection scheme.

• Journal of Auto-vehicle Safety Association
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• v.14 no.1
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• pp.26-31
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• 2022

Changwon City has the second highest accident rate with 79.6 according to the city bus accident rate. In fact, 250,000 people use the city bus a day in Changwon, The number of accidents is increasing gradually. In addition, a recent fire accident occurred in the engine room of a city bus (CNG) in Changwon, which has gradually expanded the public's anxiety. In the case of business vehicles, the government conducts inspections with a short inspection cycle for the purpose of periodic safety inspections, etc., but it is not in the monitoring stage. In the case of city buses, the operation records are monitored using Digital Tacho Graph (DTG). As such, driving records, methods, etc. are continuously monitored, but inspections are conducted every six months to ascertain the safety and performance of automobiles. It is difficult to identify real-time information on automobile safety. Therefore, in this study, individual automobile management solutions are presented through machine learning techniques of inspection results based on driving records or habits by linking DTG data and Vehicle Inspection Management System (VIMS) data for city buses in Changwon from 2019 to 2020.

• International Journal of Highway Engineering
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• v.18 no.5
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• pp.105-115
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• 2016

PURPOSES : This study was initiated to analyze the characteristics of bus traffic accidents, by bus types, using the decision tree in order to establish customized safety alternatives by bus types, including the intra-city bus, rural area bus, and inter-city bus. METHODS : In this study, the major elements involved in bus traffic accidents were identified using decision trees and CHAID algorithm. The decision tree was used to identify the characteristics of major elements influencing bus traffic accidents. In addition, the CHAID algorithm was applied to branch the decision trees. RESULTS : The number of casualties and severe injuries are high in bus accidents involving pedestrians, bicycles, motorcycles, etc. In the case of light injury caused by bus accidents, different results are found. In the case of intra-city bus accidents, the probability of light injury is of 77.2% when boarding a non-owned car and breaching of duty to drive safely are involved. In the case of rural area bus accidents, the elements showing the highest probability of light injury are boarding an owned car, vehicle-to-vehicle accidents, and breaching of duty to drive safely. In the case of intra-city bus accidents, boarding owned car, streets, and vehicle-to-vehicle accidents work as the critical elements. CONCLUSIONS : In this study, the bus accident data were categorized by bus types, and then the influential elements were identified using decision trees. As a result, the characteristics of bus accidents were found to be different depending on bus types. The findings in this study are expected to be utilized in establishing effective alternatives to reduce bus accidents.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.28-35
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• 1997

Occupant injuries are always possible in a rollover accident, one of the major accidents in a bus. Thus the structure of body frame should have sufficient strength to protect passengers under accidental loads,. ECE(Economic Commission for Europe) regulation No.66 prescribes that residual space shall be preserved in the passenger compartment during and after the structure has been subjected to the prescribed rollover test. Rollover test on a bus section was completed according to the regulation. The coordinates of body section before and after rollover were measured, and it was checked that the structure still complied with the requirements of residual space. Direct measurement on a bus is difficult because of its large size. Thus photogrammetry by photographing and 3 dimensional digital modeling was introduced, and the coordinates of each point were measured through this method.

• International Journal of Highway Engineering
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• v.15 no.6
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• pp.135-141
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• 2013

PURPOSES : The lack of details of design guideline for zig-zag shaped section approaching central bus stop leads an traffic accident proneness. So, this study analysed the geometric elements of central bus stop area in terms of vehicle dynamics and suggested design alternatives. METHODS : The study analysed a dynamic behaviour of bus moving in and out of zig-zag shaped section using Auto-Turn under scenarios. Based upon dynamic analysis, the study found out the width of overtaking lane is the most influential factor for a safe moving at zig-zag alignment. RESULTS : The width of overtaking lane at design speed of 40, 50, and 60 km/h respectively was suggested given taper ratio of 1 to 10 required for Bus Rapid Transit (BRT), and the lane width is not wider than 4.0m which possibly makes two vehicles using the same lane. Also, the width of overtaking lane which mitigates the taper ratio was suggested with the same restriction about the maximum lane width. CONCLUSIONS : The results of the study can be used to prepare a design guideline on zig-zag shaped alignment of central bus exclusive lanes. The more stable moving is expected by applying the design alternatives suggested, therefore the lower rate of traffic crashes at the vicinity of central bus stops.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.153-160
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• 2012

Various social problems such as traffic congestion, car accidents and environmental problems(air pollution, noises etc.) have been happening in the Seoul metropolitan area that has the car oriented traffic system providing cars continuously. Along with this, the financial burden caused by current oil price anxiety made paradigm shift from caroriented to public transportation-oriented. Its typical example is an arterial branch bus system changing(bus lane through the center of main road) started in Seoul in July, 2004. But study on safety analysis of bus lane and characteristic of accidents are not sufficient enough to now. The bus lanes are expanded to provide roads for better traffic operation and accidents between buses and pedestrians or ordinary vehicles are considered main problems. This study divided each bus route of median bus lane(bus-only lane through the center of main roads) and bus lane at roadside by intersection and collected and analysed data about influence variables of bus accidents chosen in each section. We constructed a logistic model using collected data. As a result, bus lane at roadside are used by both buses and other kinds of vehicles differently from median bus lane and showed such characteristic in accident influence. Therefore access management to factors causing conflict and improvement of operation management are required. In case of median bus lane, the more buses moving general vehicle lane and traffic volume of section were, the more accidents happened. In case that stop line of center lane is not backward, view blocking of vehicles turning left caused accidents.

• Journal of Korean Society of Transportation
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• v.32 no.1
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• pp.63-72
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• 2014

In this paper, characteristics and types of vehicle accidents involving buses that differ from common passenger cars are analyzed. When heavy vehicles are involved in collision accidents, the external impulse conveyed through bus tire from road surface cannot be ignored, so the conventional rigid-body impact model cannot be applied. As a solution, an analysis model which directly considers the tire impulse or considers the bus as moving barrier has been proposed. Also, as there are many instances in which the location of contact point or coefficients related to rotational motion cannot be estimated, utilization of point-mass collision model has been sought. By applying the proposed analysis model to an actual accident case and comparing with the result of the conventional analysis which does not consider the tire impulse, it is shown that the velocity of bus and other values close to the actual amount can be obtained.

• Journal of Korean Medicine Rehabilitation
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• v.26 no.2
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• pp.133-144
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• 2016

Objectives This study was designed to find out influential factors associated with Hospitalization of the patients from traffic accident by Groups. Methods Based on the medical charts, we analyzed statistical study of 486 patients putting them into two groups to identify the factors associated with the duration of hospitalization involving age, sex, elapse day (Interval between time of injury and visit to hospital), and the types of accident. Patients in group A were diagnosed with a mere 'sprain', and patients in Group B had other symptoms accompanied by 'sprain'. Results 1. In group A, cervical sprain was the most and male patients with the symptom outnumbered female patients. In group B, headache was most where female patients had the symptom 1.7 times more than male patients. 2. Female patients in group B were found to stay for a longer period of time in the hospital than the male counterparts (p<0.05). 3. Both group A and B have positive correlation between length of hospital stay and age though group B exhibited stronger correlation. 4. Patients who had accident while riding bus in group A and those who were pedestrians in group B were found to stay in the hospital for a significantly longer period of time than those who had any other types of accident (p<0.05). Conclusions We noticed that hospital stay lengthened when the patients were older and when they had accidents while riding bus in Group A whereas in Group B, patients stayed longer when they were females and older as well as when they were pedestrians in accidents.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.1-15
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• 2016

This study aims to develop a model by which city bus drivers who are likely to cause an accident can be figured out based on the information about their actual driving records. For this purpose, from the information about the actual driving records of the drivers who have caused an accident and those who have not caused any, significance variables related to traffic accidents are drawn, and the accuracy between models is compared for the classification models developed, applying a discriminant analysis and logistic regression analysis. In addition, the developed models are applied to the data on other drivers' driving records to verify the accuracy of the models. As a result of developing a model for the classification of drivers who are likely to cause an accident, when deceleration ($X_{deceleration}$) and acceleration to the right ($Y_{right}$) are simultaneously in action, this variable was drawn as the optimal factor variable of the classification of drivers who had caused an accident, and the prediction model by discriminant analysis classified drivers who had caused an accident at a rate up to 62.8%, and the prediction model by logistic regression analysis could classify those who had caused an accident at a rate up to 76.7%. In addition, as a result of the verification of model predictive power of the models showed an accuracy rate of 84.1%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.446-452
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• 2020

As the use of children's school buses increases, accidents caused by the negligence of school bus drivers and ride carers have also increased significantly. To prevent such accidents, the government is coming up with various policies. We propose an accident prevention and safety management system for children's school buses. Through this system, bus drivers can easily check whether each child is seated and whether the seat belt is used, so it is possible to quickly respond to children's conditions while driving. With the ability to recognize faces by analyzing camera images, children can use a seat belt that is automatically adjusted to their height. It is therefore possible to prevent secondary injuries that may occur in the event of a traffic accident. In addition, a sleeping child-check system is provided to confirm that all children get off the bus, and a text service is provided to inform parents of their children's locations in real time. Based on Raspberry Pi, the system is implemented with cameras, pressure sensors, motors, Bluetooth modules, and so on. This proposed system was attached to a bus model to confirm that the series of functions work correctly.