• Journal of the Korean Mathematical Society
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• v.35 no.3
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• pp.727-740
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• 1998

Controlling traffic lights at a bottleneck, in [5] a time of open passage is called optimal, if it minimizes the first moment of the asymptotic distribution of the queue length. The discussion of the first moment as function of the time of open passage is based on an analysis of the behavior of a fixed point when varying control parameters and delivers theoretical and computational aspects of the traffic problem.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.560-567
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• 2019

South Korea, which has entered an aged society, is about to enter a super-aged society in 2025. With the increase of an aging population, traffic accidents by aged drivers have been settled as a social problem. Now, when Korea is facing a super-aged society to come, a study was conducted to prevent traffic accidents that occur while the elderly people are driving through a disaster prevention design. For theoretical research, this study examined the concept and necessity of disaster prevention design, the present condition of an aged society, aged drivers' physical and cognitive characteristics, and the policies related to the forms of traffic lights the elderly people see. In addition, to propose the design, this study investigated and analyzed the traffic safety forms and colors of the International Standards Organization and proposed the first and second forms of the design of traffic lights for the gradual improvement of the traffic lights based on that. The first improved design form is a plan for displaying a triangle, an arrow with a large area, and a quadrangle in the lens of the head of the existing traffic lights, and the second improved design form is a plan for introducing a new traffic light head and forming the traffic light with a bigger triangle, an arrow with a large area and a quadrangular lens. Since it has a visually clearer form than the present traffic lights, it is expected that aged drivers who have physical and cognitive characteristics due to aging can secure better visibility and conspicuity and that they can make better reflex responses than they can now, also in the change of driving environment (rain and heavy snowstorm, etc.). In addition, it is expected that this study would be a preceding study to prepare standard guidelines on traffic safety signs other than traffic lights to be prepared for the super-aged society.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.103-104
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• 2011

In this paper, an organic signal control method for the traffic lights system is suggested. To do this, Programmable Logic Controller(PLC) and position sensor are utilized to manufactured a traffic lights signal control system. An operating example of the manufactured traffic lights system in special situation is given to illustrate that the proposed method is effective better than the existing method.

• Journal of the Semiconductor & Display Technology
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• v.14 no.2
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• pp.29-34
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• 2015

Traffic lights are common in cities and are important cues for the path planning of intelligent vehicles. In this paper, we propose a robust and efficient algorithm for recognizing traffic lights from video sequences captured by a low cost off-the-shelf camera. Instead of using color information for recognizing traffic lights, a shape based approach is adopted. In learning and detection phase, Histogram of Oriented Gradients (HOG) feature is used and a cascade classifier based on Adaboost algorithm is adopted as the main classifier for locating traffic lights. To decide the color of the traffic light, a technique based on histogram analysis in HSV color space is utilized. Experimental results on several video sequences from typical urban environment prove the effectiveness of the proposed algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2129-2137
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• 2015

Lots of research and development works have been actively focused on the self-driving vehicles, locally and globally. In order to implement the self-driving vehicles, lots of fundamental core technologies need to be successfully developed and, specially, it is noted that traffic lights detection and recognition system is an essential part of the computer vision technologies in the self-driving vehicles. Up to nowadays, most conventional algorithm for detecting and recognizing traffic lights are mainly based on the color signal analysis, but these approaches have limits on the performance improvements that can be achieved due to the color signal noises and environmental situations. In order to overcome the performance limits, this paper introduces the morphological analysis for the traffic lights recognition. That is, by considering the color component analysis and the shape analysis such as rectangles and circles simultaneously, the efficiency of the traffic lights recognitions can be greatly increased. Through several simulations, it is shown that the proposed method can highly improve the recognition rate as well as the mis-recognition rate.

• Journal of Cadastre & Land InformatiX
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• v.52 no.1
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• pp.81-93
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• 2022

Recently, there have been many studies on object recognition around the vehicle and recognition of traffic signs and traffic lights in autonomous driving. In particular, such the recognition of traffic lights is one of the core technologies in autonomous driving. Therefore, many studies for such the recognition of traffic lights have been performed, the studies based on various deep learning models have increased significantly in recent. In addition, as a high-quality AI training data set for voice, vision, and autonomous driving is released on AIHub, it makes it possible to develop a recognition model for traffic lights suitable for the domestic environment using the data set. In this study, we developed a recognition model for traffic lights that can be used in Korea using the AIHub's training data set. In particular, in order to improve the recognition performance, we used various models of YOLOv4 and YOLOv5, and performed our recognition experiments by defining various classes for the training data. In conclusion, we could see that YOLOv5 shows better performance in the recognition than YOLOv4 and could confirm the reason from the architecture comparison of the two models.

• Journal of Korea Multimedia Society
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• v.20 no.12
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• pp.1901-1912
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• 2017

Traffic lights at night are usually framed in the image as bright regions bigger than the real size due to glow effect. Moreover, the colors of lighting region saturate to white. So it is difficult to distinguish between different traffic lights at night. Many related studies have tried to decrease the glow effect in the process of capturing images. Some studies drastically decreased the shutter time of the camera to reduce the adverse effect by the glow. However, this makes the video too dark. This study proposes a new idea which utilizes the glow effect. It examines the outer radial region of traffic light. It presents an algorithm to discriminate the color of traffic light by the analysis of the outer radial region. The advantage of the proposed method is that it can recognize traffic lights in the image captured by an ordinary black box camera. Experimental results using seven short videos show the performance of traffic light recognition reporting the precision of 96.4% and the recall of 98.2%. These results show that the proposed method is valid and effective.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.114-120
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• 2009

In outdoor visible light communication channels and LED road illumination communications for the intelligent transport systems (ITS), inter symbol interference (ISI) due to multipath propagation prevents high data rate transmission. Indoor wireless optical communication systems utilizing white LED lights and on the road illumination have been studying about it. Generally, plural lights are installed in room and considered to the traffic information system using existing LED traffic lights. Therefore, their optical path difference must be considered. In this paper, the influence of an optical path difference has been investigated and two approaches against this problem are introduced. One uses on-off keying, return-to-zero (OOK-RZ) coding and the other uses optical orthogonal frequency division multiplexing(OFDM).

• Journal of Information Processing Systems
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• v.7 no.1
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• pp.1-16
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• 2011

With the increasing number of vehicles in use in our daily life and the rise of traffic congestion problems, many methods and models have been developed for real time optimisation of traffic lights. Nevertheless, most methods which consider real time physical queue sizes of vehicles waiting for green lights overestimate the optimal cycle length for such real traffic control. This paper deals with the development of a generic hybrid model describing both physical traffic flows and control of signalised intersections. The firing times assigned to the transitions of the control part are considered dynamic and are calculated by a simplified optimisation method. This method is based on splitting green times proportionally to the predicted queue sizes through input links for each new cycle time. The proposed model can be easily translated into a control code for implementation in a real time control system.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.161-167
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• 2004

While most or fixed-time control systems such as UTCS produce the signal timing plans that either maximizing bandwidth or minimizing a disutility index of delay and stops, cannot consider the fluctuation of traffic flow. One category of the traffic-response control systems, which make small changes on a predefined signal plan such as SCOOT, cannot be easily modified for feedback real-time control schemes based on observation of variables other than traffic flow. The other category, which decide to whether switch the traffic lights or not at each step of time as in PRODYN, does not adequately consider the relations between traffic flows and traffic lights at each step of time. In this paper we present a complete formulation that adequately consider the relations between traffic flows and traffic lights at each step of time. The formulation is a binary mixed integer linear programing (BMILP) that obtain traffic lights at each step for minimizing delay. Since numarical examples for application of the proposed model illustrated that the model adequately produced dynamic traffic signal plans minimizing delay at each step, the model may be expected to contribute to advanced transportation management systems (ATMS) for dynamic traffic signal control.