• 대한인간공학회지
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• 제31권2호
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• pp.371-377
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• 2012

Objective: The aim of this study is to investigate effect of driver's cognitive distraction on driver's physiological state and driving performance, and then to determine parameters appropriate for detecting the cognitive distraction. Background: Driver distraction is a major cause of traffic accidents and poses a serious threat to traffic safety due to ever increasing use of in-vehicle information systems and mobile phones during driving. Cognitive distraction, among four different types of distractions, prevents a driver from processing traffic information correctly and adapting to change in surround vehicle behavior in time. However, the cognitive distraction is more difficult to detect because it normally does not involve significant change in driver behavior. Method: A full-scale driving simulator was used to create virtual driving environment and situations. Participants in the experiment drove the driving simulator in three different conditions: attentive driving with no secondary task, driving and conducting secondary task of adding numbers, and driving and conducting secondary task of conversing with an experimenter. Parameters related with driver's physiological state and driving performance were measured and analyzed for their change. Results: The experiment results show that driver's cognitive distraction, induced by secondary task of addition and conversation during driving, increased driver's cognitive workload, and indeed brought change in driver's physiological state and degraded driving performance. Conclusion: The galvanic skin response, pupil size, steering reversal rate, and driver reaction time are shown to be statistically significant for detecting cognitive distraction. The appropriate combination of these parameters will be used to detect the cognitive distraction and estimate risk of traffic accidents in real-time for a driver distraction warning system.

• Journal of Power Electronics
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• 제12권4호
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• pp.519-527
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• 2012

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1340-1343
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• 1996

In this study, we developed the drowziness prevention system to detect the driver's drowziness and relieve the driver. A computer vision method was proposed to detect the driver's drowziness. We extracted the eyes and mouth in the face image and tracked the positions from the image sequencies in real time. The eye blink duration and yawning was used as the parameters of drowziness. Wehn the drowziness state of a driver is detected, the driver is refreshed by the scent generator and the alarm. Also, the driver's bio-signal is acquired and analysed the vigilance state.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.822-824
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• 2007

This paper investigated a gate driver circuit with amorphous silicon for mobile TFT-LCD. In the conventional circuit, the fluctuation of the off-state voltage causes the fluctuation of gate line voltages in the panel and then image quality becomes worse. Newly designed gate driver circuit with dynamic switching inverter and carry out signal reduce the fluctuation of the off-state voltage because dynamic switching inverter is holding the off-state voltage and the delay of carry signal is reduced. The simulation results show that the proposed a-Si:H gate driver has low noise and high stability compared with the conventional one.

• 대한의용생체공학회:의공학회지
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• 제18권3호
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• pp.315-323
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• 1997

Driving is a complex vigilance task that includes improper lookout, excessive speed and inattention. The primary objective of this research is to detect driver drowsiness so that the driver can be alerted to an impending traffic accident in performance. We developed the automatic detection and warning system during drowsy driving. A drowsiness detection system must be able to monitor driver status and detect the detrimental changes of a driver performance. Eyeblink has been found to be a reliable factor of drowsiness detection in earlier studies. As an additional parameter, we also considered the yawning which often occurs in a low vigilance state and predicts the drowsy state. We used a computer vision method to extract the eyeblink and yawning in the face image sequences. When the drowsy state was detected, the driver was refreshed by alarming device and menthol scent generator after deciding the warning level by fuzzy logic. For the evaluation of our system, we measured the physiological parameters such as EOG and EEG. The results indicated that it is possible to detect and alert the driver drowsiness temporarily or continuously by using our system.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.90-94
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• 1996

We studied the problem of driver's low vigilance state which is related to the one reason of traffic accidents. In this paper, we developed the drowsiness warning system for a drowsy driver. To extract the eyes and mouth from the driver's facial image in real time, a computer vision method was used. The eye blink duration and yawning were used as measurement parameters of drowsiness detection. When the drowsy state of a driver was detected, the driver was refreshed by the scent generator and the alarm. Also, the driver's bio-signal was acquired and analyzed to measure the vigilance state.

• 한국멀티미디어학회논문지
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• 제19권6호
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• pp.1024-1033
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• 2016

In this study, a system is proposed for analyzing whether driver's eyes are open or closed on the basis of images to determine driver's drowsiness. The proposed system converts eye areas detected by a camera to a color space area to effectively detect eyes in a dark situation, for example, tunnels, and a bright situation due to a backlight. In addition, the system used a thickness distribution of a detected eye area as a feature value to analyze whether eyes are open or closed through the Support Vector Machine(SVM), representing 90.09% of accuracy. In the experiment for the images of driver wearing glasses, 83.83% of accuracy was obtained. In addition, in a comparative experiment with the existing PCA method by using Eigen-eye and Pupil Measuring System the detection rate is shown improved. After the experiment, driver's drowsiness was identified accurately by using the method of summing up the state of driver's eyes open and closes over time and the method of detecting driver's eyes that continue to be closed to examine drowsy driving.

• 산업기술연구
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• 제21권B호
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• pp.273-280
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• 2001

In this study, a driver model based on the lead-lag controller for stable maneuver of a highly nonlinear, multi-dimensional, numerically stiff multibody vehicle model according to the various handling test requirements such as steady-state cornering, double lange change, etc. is presented The lead-lag controller is developed with lead and lag compensation. which use the transfer function with cross-over frequency by frequency response method. The proposed driver model is applied to a vehicle model in steady-state and slalom maneuver to verify its effectiveness and validity. The results show that the proposed path control strategy is excellent both in pursuing the desired course and stability of the vehicle.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.272-278
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• 2008

This paper investigated the a-si:H gate driver with the stepwise gate signal. In 1-chip type mobile LCD application the stepwise gate signal for low power consumption can be used by adding simple switching circuit. The power consumption of the a-Si:H gate driver can be decreased by employing the stepwise gate signal in the conventional circuit. In conventional one, the effect of stepwise gate signal can decrease slew rate and increase the fluctuation of gate-off state voltage, In order to increase the slew rate and decrease the gate off state fluctuation, we proposed a new a-Si:H TFT gate driver circuit. The simulation data of the new circuit show that the slew rate and the gate-off state fluctuation are improved, so the circuit can work reliably.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.661-662
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• 2006

This paper introduces a CMOS clock driver that shows a high efficiency of electric power (lower power consumption) with the supply of lower voltage(VDD), by taking advantage of charge recycling technology. Comparing with the existing structure, this driver showed the improved maximum efficiency of electric power; 72% and 68%, with the supplied voltage of 1.8v and 1.2v, respectively. Since the output waveform shows the tri-state operating region, utilization is expected in the digital integrated circuits.