• Korean Journal of Culture and Social Issue
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• v.13 no.4
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• pp.101-112
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• 2007

We investigated the influences of 'Circumstance Insensibility', 'Unsafe Driving', 'Incautious Driving', and 'Self-efficacy of Driving', consisting of driving confidence level, on traffic accidents. 1055 drivers conducted Driving Confidence Level Questionnaire, items about their dangerous driving experience and traffic accidents. Among them, after checking the missing items, we analyzed data of 998 drivers. As a result, we found the relation between driving confidence levels and traffic accidents. Specially, 'Circumstance Insensibility' and 'Unsafe Driving' influenced traffic accidents. However 'Circumstance Insensibility' had negative effects, the other side 'Unsafe Driving' had positive effects on traffic accidents. This result means each factor of driving confidence levels have different relation with traffic accidents. 'Incautious Driving' and 'Self-efficacy of Driving' didn't have any effects on traffic accidents in this research. In future, it should be investigated 'Incautious Driving' and 'Self-efficacy of Driving'.

• Korean Journal of Culture and Social Issue
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• v.13 no.3
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• pp.111-125
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• 2007

This study focused on novice drivers. Novice drivers get involved in more traffic accidents than the other drivers because of less driving experience. The aim of this study is to investigate the relationship between driving confidence levels and speeding, drunken driving, and traffic accidents. 192 drivers responded driving confidence levels questionnaire and driving experience items. 'Circumstance Insensibility', 'Unsafe Driving', 'Incautious Driving', and 'Self-efficacy of Driving' had significant relations with speeding in novice divers group. Especially, 'Circumstance Insensibility' showed a significant relation with speeding, drunken driving and traffic accidents. In the result of path analysis, driving confidence levels explained 22% of the speeding, 12% of the drunken driving and 21% of the traffic accidents in novice drivers group. 'Circumstance Insensibility' was most effective for traffic accidents of novice drivers. We verified that 'Self-efficacy of Driving' affects on traffic accidents via speeding.

• Korean Journal of Culture and Social Issue
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• v.12 no.3
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• pp.23-47
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• 2006

The purpose of this research is to study the relation between the change of driver's driving confidence level in the age categories and driving behavior. To survey the driving confidence level, we used the 'Driving Confidence Scale' questionnaire and surveyed the drive career, mileage, driving days, violation of traffic regulation (drunk driving, overspeed), traffic accident experience (assaulter, sufferer) together. The subjects of investigation were from 19-year-old to 80-year-old and 1,055 persons were participated in the research totally. To examinethe structure of driving confidence level, we executed the factor analysis. We compared the driving confidence level in the age categories (under 29-year-old, 30~39, 40~49, 50~64, over 65-year-old) and studied the relation between driving confidence level and driving behavior. Driving confidence level was composed of 4 factors such as 'insensibility to situation', 'unsafe driving', 'careless concentration' and 'self-efficacy of driving', and there was decreasing tendency for driving confidence level and overall driving behavior according to increasing age. Driving confidence level had the interrelation with age range, assaulting accident, suffered accident, driving period, drunk driving, overspeed, driving career and so on. We examined the difference of driving confidence level and driving behavior by dividing the participated drivers' groups into the traffic accident experienced group, drunk driving group and overspeed driving group, and there was a significant difference on driving confidence level and driving behavior between the group who had not experienced the violation of traffic regulation or traffic accident and another group who had experienced the violation of traffic regulation or traffic accident.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.185-187
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• 1999

SRM의 상 스위칭 제어방식에서 상 스위치의 온, 오프 제어정도는 인코더의 분해능뿐만 아리라 마이크로프로세서의 샘플링 주기에 의해 제약을 받게되며, 전동기의 속도가 고속으로 됨에 따라 상 스위치의 온, 오프 제어정도는 더욱 떨어지게 되어 정상운전상태가 불안전하게 된다. 따라서 본 연구에서는 SRM 구동에 적합한 저가형 인코더를 제안하고, 제안된 인코더의 출력신호를 사용하여 간단한 논리회로에 의해 상 스위치 제어방식을 제안하였다. 제안된 상 스위치 제어방식은 스위치 온, 오프각 지연이 SRM의 운전속도와 관계없게 되어 안정된 고속운전이 가능하게 되었다.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.15-22
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• 2017

The pressure safety valve is very important device for securing the safety in the facilities which is operated by high pressure gases. The performance test should be periodically inspected by relate law because the failure of pressure safety valves might be main causes of serious accidents in the industrial fields. Shop test is mainly use for inspecting the performance test of pressure safety valves but the test method is not to be a solution for securing the safety. So, the development of alternative method is required. In this paper, there is a limit to securing the safety if the performance test is with just shop test. The limitation is checked from analysis result based on performance test results of pressure safety valves. The necessity for introducing the in-service test is reviewed to surmount the limitation. As a result, in-service test method should be developed and introduced to improve the inspection efficiency and economical loss. Also, it can be reduce the risk level.

• Korean Security Journal
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• no.37
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• pp.51-82
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• 2013

Traffic safety has been dramatically enhanced thanks to recent improvements in traffic environment. Nonetheless, many traffic accidents occur due to unchanging driving practices. Therefore, this study addresses the issues of traffic fine and penalty fine policies, and seek appropriate levels of traffic fines through a public attitude survey. For this purpose, a survey was conducted on 905 adult drivers over 20 years of age from 15 provinces and metropolitan cities. Analysis results are as follows. First, traffic environment in South Korea is generally not safe. Respondents perceive violation of traffic laws such as reckless driving, speeding and drunk and driving as an important cause. Second, 61.6% of respondents experienced over one speeding annually, but only 15.2% of respondents were caught in the last three years. Third, opposition to levels of traffic fines has decreased over the past, and responses were more positive when more information was provided. Fourth, to deter moral hazard of paying traffic fines to avoid traffic penalty points, traffic fines should be at least 50,000~70,000 won higher than penalty fines. Fifth, there was less opposition to implementation of accumulated penalty policy compared to income-based differential fine levels. Sixth, traffic fines for different types of traffic violations need to be reorganized. In conclusion, this study suggests the following policy improvements for the current traffic fine and penalty fine policies for violation of traffic laws. First, enough understanding and consensus must be developed for policy improvements. Second, administrative sanctions such as giving penalty points should be considered rather than financial sanctions. Third, there should be policy improvement for accumulative penalty. Current acts of traffic law violation should be reorganized.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.217-222
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• 2016

This study investigates the design, analysis, and implementation of the square-root extended Kalman filter by using an algorithm derived by combining the Potter or Carlson algorithm with the modified Gram-Schmidt algorithm, for sensorless speed control of a permanent-magnet synchronous motor. The sensitivity of the Kalman filter to round-off errors is a well-known problem. A possible way to address this limitation is by combining the square-root concept and Kalman filter that can improve the numerical performance and solve instability-related problems such as divergence. This paper presents the design and analysis of the implementation of such a square-root extended Kalman filter. To demonstrate the performance of the proposed filter, experimental results under several operating conditions, such as high and low speeds, reversal rotation, detuned parameters and load test, have been analyzed. Further, code sizes and operation times have been compared. Experimental results establish the performance of the proposed square-root extended Kalman filter-based estimation technique for sensorless speed control of a permanent-magnet synchronous motor.

• Journal of Navigation and Port Research
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• v.38 no.1
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• pp.29-37
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• 2014

In this paper, the author consider control system design problem of the surface vessel where any types of floating units are included. To keep their motion/position, the Dynamic Positioning System(DPS) is equipped in. Even though sometimes the thrust systems are installed on them, in general the mooring winch system with the rope/wire is used. Therefore, in this paper we consider a single type mooring winch control problem to keep the vessel's position. For this, we introduce an easy and useful control approach which is based on LQ control theory. In this approach, we introduce the frequency dependent weighting matrices which give the system filters to shape frequency characteristics of the controlled system and guarantee the control performance. Based on this, we will show that the proposed approach works well.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.658-670
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• 2007

Most railroad accidents are due to human errors. In particular, most of the causes of these accidents are faults of an engine driver, such as lack of signal confirmation, insecure braking, driving by guess or force of habit. This paper identifies a problem(s) by analyzing accidents for the past 10 years and also seeks a solution to train good engine drivers in order to prevent railroad accidents. In summary, what is needed are: 1) proper placement of various manpower, 2) proper training of engine drivers, 3) proper legislation for a 2-man on board system, and 4) proper reformation of personnel management.

• Fire Science and Engineering
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• v.27 no.5
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• pp.19-25
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• 2013

The fire took place in the synthetic heat transfer fluid boiler. This study uses simulation to investigate the first, second and third passes and the temperature in the fire burner. The boiler's internal fluid is more or less unsteady due to the out of order inverter. As the operation continues, the flame's flow and speed are unsteady. The synthetic heat transfer fluid leak spouted about 120 kg/min in the form of vapor in the early period of the fire. The flame extended to the second and third passes. The highest temperature of the second and third pass is $1059^{\circ}C$ and $1007^{\circ}C$, respectively. The simulation shows that the temperature is $767^{\circ}C$ in the low part of the third pass. The synthetic heat transfer fluid spouted through the cracked part of the fire box in the first pass and accumulated on the turn table. The temperature rises to $183^{\circ}C$ in the low part of the burner. Therefore, it is expected that the temperature of the interior of the fire box is above $1200^{\circ}C$. The temperature of the burner rises to a maximum level several times in a short period. On account of that, several explosions occur in the fire burner.