• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.142-151
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• 2018

In the era of the 4th Industrial Revolution, research and development on autonomous vehicles have been actively conducted all over the world. Under these international trends, the Ministry of Land, Infrastructure and Transport is actively promoting the development of autonomous vehicles aiming at commercialization of autonomous vehicles at level 3 or higher by 2020. In the level 3 autonomous vehicle, it is essential to transfer control between the driver and the vehicle according to driving situations. Prior to the full-fledged autonomous vehicle age, this study developed a representative scenario for the safety evaluation on take-over on expressways. To accomplish this, we developed a highway driving scenario first, and then developed six control transition scenarios based on 2014 highway traffic accident data and take-over data. The variables to be considered in the developed scenarios are divided into drivers, vehicles, and environmental factors. A total of 36 variables are selected.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.3
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• pp.305-316
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• 2011

Cracked teeth are a common problem with incomplete fracture that typically shows pain on biting and temperature stimuli. The most common cause of crack is known to be the masticatory accident. Predisposing factors were aging, old restoration, and iatrogenic stress concentration, etc. Accurate diagnosis is needed for detecting the extent of crack and pulp vitality. There are many diagnostic tools like bite test, direct observation with transillumination, dye penetration, and radiographs. Immediate treatment for pain relief and occlusal adjustment would be needed. Composite resin and bonded amalgam showed favorable prognosis. Moreover, cusp protection is reliable permanent treatment for cracked teeth. The purpose of this article is to review the literature about the prevention, diagnosis, and treatment for cracked teeth.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.33-42
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• 2011

The types of the accidents caused by intra-city buses and the changing tendencies of driving attitudes are analyzed before-and-after semi-public management system of intra-city bus system is implemented. On the basis of analysis, the measures on the decrease of traffic accidents are considered and the results are as follows. First, it showed that the traffic accidents decreased generally as a result of definition of the progresses of traffic accidents of intra-city buses before-and-after the system is implemented and with the passing of time after the system was operated. Second, the factors which influence the decrease of traffic offenses before-and-after semi-public management system of intra-city bus are the decease of violation, safe driving duty and the job security. Also the cause which mostly influence to the decrease of traffic accidents is defined. Finally, the measures of decrease of traffic accidents are arranged and proposed as a result of PROXSCAL method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.425-430
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• 2008

To verify the system performance of portable AE leak diagnosis system which can measure with moving conditions, AE activities such as RMS voltage level, AE signal trend, leak rate degree according to AE database, FFT spectrum were measured during operation on total 11 valves of the secondary system in nuclear power plant. AE activities were recorded and analyzed from various operating conditions including different temperature, type of valve, pressure difference, valve size and fluid. The results of this field study are utilized to select the type of sensors, the frequency band for filtering and thereby to improve the signal-to-noise ratio for diagnosis for diagnosis or monitoring of valves in operation. As the final result of application study above, portable type leak diagnosis system by AE was developed. The outcome of the study can be definitely applied as a means of the diagnosis or monitoring system for energy saving and prevention of accident for power plant valve. The purpose of this study is to verify availability of the acoustic emission in-situ monitoring method to the internal leak and operating conditions of the major valves at nuclear power plants. In this study, acoustic emission tests are performed when the pressurized temperature water and steam flowed through glove valve(main steam dump valve) and check valve(main steam outlet pump check valve) on the normal size of 12 and 18 ". The valve internal leak monitoring system for practical field was designed. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. To improve the reliability, a judgment of leak on the system was used various factors which are AE parameters, trend analysis, frequency analysis, voltage analysis and amplitude analysis of acoustic signal emitted from the valve operating condition internal leak.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.701-708
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• 2018

Human error is an important cause of maritime accidents and the identification of human error is fundamental to maritime-accident preventions. In particular, the pattern of technical behavior taken in the circumstance of bridge teams(navigator & helmsman) provides important information to identify human error. The purpose of this study is to identify and analyze technical behavior pattern of bridge teams using Williamson's turn for rescue of persons overboard. The focus of this study is to build and analyze a cognitive model of the human behavior factors of the bridge teams in the process of implementing the experiments. The experimental environment was constructed using a ship-handling simulator and conducted an experiment on participants from 24 bridge teams. As a result of the experiment, it was able to identify the behavior pattern of the ship's maneuvering and maintain trajectory using the rudder and engine. This study is expected to correct human error in the bridge teams application to the certification and training of seafarers.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.91-98
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• 2020

Since disaster-safety accidents cause serious damage to human life and property, preparations and responses have been critically challenged by the country and industry. Recently, the government and industry have recognized its importance and are seeking solutions to the causes of disasters in various ways. If virtual reality technology is actively used, it will be easier to prepare and train for disasters, as the social costs will be reduced. However, academic research on this has not been actively studied. In particular, it seems difficult to seek data that comprehensively analyzes or organizes disaster-safety with virtual reality contents. In this paper, we analyze the current status of domestic and overseas focused on virtual reality disaster/safety contents, examine its characteristics, and point out the direction required for advanced service in the future. To this end, the implications of the numerical data of the accident type have been derived, and the direction of development of public institutions, academic research, and industry have also been investigated. Finally, technical considerations are presented as well.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.605-613
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• 2007

In order to overcome the difficulties of quantitative risk analysis such as complexity of model, we propose a systematic methodology for risk quantification of railway system which consists of 6 steps: The identification of risk factors, the determination of major scenarios for each risk factor by using event tree, the development of supplementary fault trees for evaluating branch probabilities, the evaluation of event probabilities, the quantification of risk, and the analysis in consideration of accident situation. In this study, in order to address the feasibility of the propose methodology, this framework is applied to the prototype risk model of nation-wide railway level crossings. And the quantification result based on the data of 2005 in Korea will also be presented.

• The Journal of Internal Korean Medicine
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• v.19 no.1
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• pp.97-113
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• 1998

BACKGROUND The purpose of this study was to investigate disability of the patients after stroke, clinical applicability and usefulness of the FIM in evaluating the functional abilities and to assess the characteristics of the patients after stroke. And this study examined difference by predictive factors on the treatment outcome. METHOD The study was composed of 31 stroke patients who were within 1 week after stroke and had been treated in hospital more than 4 weeks. Improving rate was measured by using the Functional Independence Measure(FIM), and the correlation was analyzed between Motor FIM and Cognitive FIM. We analyzed significant meaning statistically in the mean value of FIM. RESULT 1. There was no significant meaning statistically in the mean value of FIM that was between both at admission and after 2 weeks. But there was proportional correlation between both at admission and after 4 weeks, and significant meaning statistically. 2. There was proportional correlation between both FIM and Motor FIM, and significant meaning statistically. But there was no significant meaning statistically between both FIM and Cognitive FIM. 3. There was no significant meaning statistically between both FIM and sex, age, side of weakness, stroke subtype, hypertension, hypercholesterolemia, diabetes mellitus, heart disease, starting point of rehabilitation therapy and past history of cerebral vascular accident. While dysarthria affected functional recovery in stroke patients, and significant meaning statistically. CONCLUSION 1. FIM appeared to be a valid and reliable method to measure the functional abilities of the patients after stroke. 2. Only one thing between Motor FIM and score didn't influence FIM score. 3. Dysarthria affected functional recovery in stroke patients, and it is the statistically significant factor.

• Journal of Hydrogen and New Energy
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• v.25 no.2
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• pp.161-172
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• 2014

Hydrogen, which can be produced from abundant and widely distributed renewable energy resources, seems to be a promising candidate for solving the concerns for improving energy security, urban air pollution, and reducing greenhouse gas emissions. The two primary motivating factors for hydrogen economy are fossil fuel supply limitations and concerns about global warming. But the safety issues associated with hydrogen economy need to be investigated and fully understood before being considered as a future energy source. Limited operating experience with hydrogen energy systems in consumer environments is recognised as a significant barrier to the implementation of hydrogen economy. To prevent unnecessary restrictions on emerging codes, standards and local regulations, safety policies based on real hazards should be developed. This article studies briefly the direct impact-distances from hazard events such as hydrogen release and jet fire, and damage levels from hydrogen gas explosion in a confined space. Based on the direct impact-distances indicated in the accident scenarios and consumer environments in Korea, the safety policies, which are related to hydrogen filling station, hydrogen fuel cell car, portable fuel cell, domestic fuel cells, and hydrogen town, are suggested to implement hydrogen economy. To apply the safety policies and overcome the disadvantages of prescriptive risk management, which is setting guidance in great detail to management well known risk but is not covering unidentified risk, hybrid risk management model is also proposed.

• Journal of the Korean Society of Safety
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• v.31 no.1
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• pp.126-131
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• 2016

Although many studies have been conducted to find solutions to deal with human errors effectively, violations have been rarely studied in depth. The violation is a type of human error when an employee takes an action with intention but does not intend harmful outcomes. Violations have characteristics similar to other types of human errors but it is difficult to understand the intention of an employee from accident reports. The objective of this study is to develop a conceptual model of violation errors for preventing accidents/failures in a nuclear power plant from violation errors. Based on the previous studies, the characteristics of violations were collected in 9 categories and 136 items. They were classified into three-kinds of characteristics (human-related, task-related, organization-related characteristics) to construct conceptual models of routine/situational violations. The representative cases of accidents/failures in a nuclear power plant were analyzed to derive the specific types of routine/situational violation occurrence. Three types of conceptual model for each violation were derived according to whether the basic, human-related, and task-related characteristics are included or not. The conceptual models can be utilized to develop guidelines to support employees preventing routine/situational violations and to develop supportive system in nuclear power plant.