• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.131-137
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• 2009

Recent technological advances made a vehicle more intelligent to increase safety and comfort. An intelligent vehicle provides drivers with safety warning information through audible sounds, visual displays, and tactile devices. However, elderly drivers have been known to decrease the physical and cognitive abilities such as muscular strength, hearing, eyesight, short term memory, and spatial perception. Therefore, possible age-related deficits should be considered to design an effective warning system. This paper aims to evaluate the impact of advancing age on response performance on audible safety warnings which are widely used for alerting driving hazards. In order to understand the effect of age-related hearing loss and movement slowing, three sound characteristics (frequency, intensity, and period) and three age groups (younger, middle, and older) are considered. Data was drawn from 38 drivers who drove a simulated rural road in a driving simulator. Experimental results show that age influences driver's response performance. In conclusion, the appropriate range of a warning sound is suggested.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.668-676
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• 2016

The accelerated convergence of automobiles and ICT has led to an increase in in-vehicle electronic devices designed to enhance the safety and convenience of drivers. Consequently, the information presentation on in-vehicle display systems for drivers and passengers need to be taken into account in order to guarantee driving stability while satisfying the needs of UX-based design users. This study compared and evaluated requirements for information items shown on in-vehicle displays regarding driving safety and convenience by groups according to driving career. A total of 38 information items related to safety and convenience that can be displayed while driving and pulling over were collected. Their level of necessity was tested and evaluated by 234 drivers. Using the results, we conducted a comparative analysis on the requirements for information presentation on in-vehicle display systems by groups according to driving career.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.54-58
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• 2013

In recent days, vehicles have become equipped with electric systems that assist and help drivers driving safe by reducing possible accidents. LDWS(Lane Departure Warning System) and LKAS(Lane Keeping Assistant System) are involved in assist systems, especially for lateral motion of vehicles. Sudden and inattentive lateral motion of vehicles due to drivers' fatigue, illness, inattention, and drowsiness are major causes of accidents in highway. LDWS and LKAS provide drivers with warnings or assisting power to reduce any possibilities of accidents. In order to prevent or minimize the possibilities of accidents, lateral motion control of vehicles has been introduced in this research. DGPS/RTK(Differential Global Positioning System/Real Time Kinematics) and GIS(Geographic Information System) have been used to obtain the current position of vehicles and decide when activate controlling lateral motion of vehicles. The presented lateral motion control has been validated with actual vehicle tests.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.109-115
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• 2017

In order to increase the productivity of the logistics center and transportation, we try to articulate the priority ranking factors of the productivity influenced by the personality of the field workers (logistics center workers) and functional workers (drivers) via the AHP technique Individual personality was studied by applying the Big 5 model of psychological factors (openness, Conscientiousness, extroversion, Agreeableness, neuroticism). In this paper, extraversion was critically analyzed as a priority factor. A trait of extroversion is a strongly active and individual personality. In this study, the field workers are logistics center workers and the functional workers are drivers. They are interactively influenced in the In & Out operation. For example, when it comes to 'up and down work' and 'inspection work', the functional workers perform 'up and down work' and 'delivery work' and the field workers perform 'inspection work'. Stressing on the respective work has an affect on work productivity. Inspection workforce has something to do with inventory management. Functional workforce affects the delivery workforce. Delivery work is positively correlated with customer satisfaction. Nevertheless, as a result of research, extrovert personality that has something to do with an energetic activity would not affect on the implementation of their operation. In addition, personal extraversion of workers and drivers in the warehouse can have a significant impact on job commitment and productivity improvement.

• Journal of the Ergonomics Society of Korea
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• v.27 no.1
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• pp.1-7
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• 2008

Work related musculoskeletal disorders (WMSDs) have become a hot issue within the Korean workplace for the past several years. Recently, the effect of job related stress on WMSDs, cerebro-cardiovascular diseases, and psychiatric disorders has been steadily increasing. The study conducted questionnaire of Korea version job stress model, WMSDs from NIOSH, CES-D (Center for Epidemiologic Studies Depression Scale), and STAI (State-Trait Anxiety Inventory) against train drivers. The results of this study show that the job stress score of the train drivers is high in the areas of physical environment, job latitude, interpersonal conflict, job insecurity, and organization system. The relation between job stress and WMSDs nd, interpersonal conflict, job insecurity and organizational system. The relation between job stress and depressive disorders showed statistical significance in the areas of job demand, job insecurity and low reward. Finally, the relation between job stress and anxiety disorders showed statistical significance in areas of job demand, interpersonal conflict, job insecurity, organizational system and low reward.

• Journal of Power Electronics
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• v.6 no.1
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• pp.73-82
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• 2006

Plasma display panels (PDPs) have a serious thermal problem, because the luminance efficiency of a conventional PDP is about 1.5 1m/W and it is less than $3\~5\;lm/W$ of a cathode ray tube (CRT). Thus there is a need for improving the luminance efficiency of the PDP. There are several approaches to improve the luminance efficiency of the PDP and we adopted a driving PDP at high frequency range from 400kHz up to over 700kHz. Since a PDP is regarded as an equivalent inherent capacitance, many types of sustaining drivers have been proposed and widely used to recover the energy stored in the PDP. However, these circuits have some drawbacks for driving PDPs at high frequency ranges. In this paper, we investigate the effect of the parasitic components on the PDP itself and on the driver when the reactive energy of the panel is recovered. Various drivers are classified and evaluated based on their suitability for high frequency drivers. Finally, a current-fed driver with a DC input voltage bias is proposed. This driver overcomes the effect of parasitic components in the panel and driver. It fully achieves a ZVS of all full-bridge switches and reduces the transition time of the panel polarity. It is tested to validate the high frequency sustaining driver and the experimental results are presented.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.42-48
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• 2016

Light-emitting diode (LED) drivers are recently replacing fluorescent lamps; these drivers can operate adaptively with various ballasts without modifying and removing such ballasts. To satisfy these trends, a LED driver that is compatible with both electronic and magnetic ballasts is proposed in this study. Unlike conventional LED drivers, the proposed driver has a ballast recognition circuit and a mode selection circuit to operate ballasts at optimal conditions. Therefore, it features low voltage stress, high efficiency, and good compatibility with both electronic and magnetic ballasts. Moreover, it can be compatible with a wide selection of ballasts from various manufacturers. To confirm the validity of the proposed LED driver, results of the theoretical analysis and experimental verification performed on a 15 W-rated prototype are presented.

• Journal of the Ergonomics Society of Korea
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• v.18 no.1
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• pp.133-147
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• 1999

Traffic signs without a cognitive consideration in their design may cause information-processing problem that could result in a mental confusion among drivers often lead to a serious traffic accident. Therefore, in this study, several traffic signs currently used in Seoul Metropolitan area have been sampled and analyzed to identify design problems that usually caused by neglecting drivers cognitive ability. To classify the practical design problems, five major information-processing problems have been suggested: indistinguishable information, information conflict, missing information, sign-load mismatch, and information overload. In order to solve these cognitive problems, new traffic signs have been suggested in this study. An experiment was also performed to validate the new traffic sign. Twenty-four healthy subjects participated in the experiment. They were asked to answer the Question after observing the traffic signs continuously displayed on computer screen. The result indicated that subjects improved the accuracy in understanding the signs by 1.4 times when they used the suggested traffic sign compared to the old one. Based upon the results, a cognitive guideline was suggested for correct and speedy reading of traffic signs by improving information processing and reducing of human error. In conclusion, the traffic sign may well be applied to design an intelligent traffic sign system to increase the safety and comfort of drivers, especially in complex load condition.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.1-9
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• 2014

This study tried to propose plan to prevent human error of railroad driver among human error of railroad worker which takes great share in railroad accident. For this, in order to maintain correlation between the accident actually occurred after the opening of high-speed railroad and experience of accident that did not happened, survey on respondent was analyzed by conducting survey on KTX captain who is working in driving work of high-speed railroad, and instruction management team manager who manages KTX captain and captain. This thesis classified the factors by human factor, job factor, environment factor, organization factor, and established human error management model by comparing and analyzing how each factors have spatial interrelations with a railroad accident. The purpose of this study is to contribute to make safe railroad, and reliable railroad by preventing human error accident by minimizing human error of high-speed railroad drivers, and improving driving workers to cope accurately and fast with irregularities through various institutional improvement, improvement of driving facilities, improvement of operating room environment, and improvement of education system.

• Journal of Auto-vehicle Safety Association
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• v.7 no.3
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• pp.30-34
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• 2015

This study examined the Korean drivers' acceptance of SAS(Speed Assistance systems) and traffic sign conditions in Korea roads for SLIF(Speed Limit Information Function) that is a part of SAS. Exceeding the speed limit is a factor in the severity of many road accidents and SAS would help the driver to observe a speed limit by warning and/or effectively limiting the speed of the vehicle. SAS are in the initial phase in Korea, Korean drivers could not be familiar with automatical speed limiting during driving, SAS interface design would be considered to be more readily acceptable to the public. And advanced SAS have been introduced onto the market which are able to inform the driver of the current speed limit based on camera and/or digital maps based SLIF. These systems are based on external data using sensors, so environmental conditions are an important factor which could cause malfunction of SLIF functions.