• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.667-675
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• 2013

This paper presents vision-based techniques for underwater landmark detection, map-based localization, and SLAM (Simultaneous Localization and Mapping) in structured underwater environments. A variety of underwater tasks require an underwater robot to be able to successfully perform autonomous navigation, but the available sensors for accurate localization are limited. A vision sensor among the available sensors is very useful for performing short range tasks, in spite of harsh underwater conditions including low visibility, noise, and large areas of featureless topography. To overcome these problems and to a utilize vision sensor for underwater localization, we propose a novel vision-based object detection technique to be applied to MCL (Monte Carlo Localization) and EKF (Extended Kalman Filter)-based SLAM algorithms. In the image processing step, a weighted correlation coefficient-based template matching and color-based image segmentation method are proposed to improve the conventional approach. In the localization step, in order to apply the landmark detection results to MCL and EKF-SLAM, dead-reckoning information and landmark detection results are used for prediction and update phases, respectively. The performance of the proposed technique is evaluated by experiments with an underwater robot platform in an indoor water tank and the results are discussed.

• Journal of Korea Game Society
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• v.12 no.5
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• pp.5-12
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• 2012

The information represented by graphic is preferred more than by text to the game generation familiar to computer games in the cognitive style. The learning to solve the math problems represented by graphic is significantly effective to improve learner's problem-solving power in math education. In this paper, we proposed a method of graphic representation of mathematical sentences for effective learning of the game generation. The proposed method arranges the unit informations in the logical structure and represent the logical interrelation between the informations by symbols, line segments, or arrows using the graphic elements with good visibility for the game generation to recognize easily and to understand accurately the logical meaning. The proposed method is able to represent accurately the math sentences until the detail level that appears the tense and the voice of the sentences differently from the previous graphic representation method's ability. The proposed method could be used as learning tools and used widely to represent graphically mathematical informations for the instructional scaffolding of an educational game in oder that the game generation could learn effectively.

• Journal of the Korea Computer Graphics Society
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• v.17 no.2
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• pp.11-16
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• 2011

In computer graphics, shadows play a very important role as a hint of inter-object distance as well as themselves in terms of realism. To represent shadows, some traditional methods such as shadow mapping and shadow volume have been frequently used for the purpose. However, the rendering results are not natural since they assume the point light. On the contrary, an area light can render soft-shadows, but its computation is too burdensome due to integral over the whole light source surface. Many alternatives have been introduced, back-projection of occluder onto the light source to get visibility of light or filtering of shadow boundary by calculating size of penumbra. But they also have problems of light bleeding or ringing effects because of low order approximation, or low performance. In this paper, we describe a method to improve those problems using shadow atlas.

• Korean Journal of Oriental Medicine
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• v.12 no.3 s.18
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• pp.31-47
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• 2006

Nowadays Korean governments use Information Technology to improve the quality of life for a people. One of these tries is building the Food Tracing System based on Information Technology. Koreans have big concern about food that is good for health. The Food Tracing System means that the system can follows, traces, and records every steps of production and delivery of food and its ingredient. And this process should be identified and grouped by using tags, marks, and other methods. For example, producer of ingredient, processing steps of food, delivered place could be traced. In addition to food, medical herbs need consumer's trust in production and delivery. To trace and prosecute contaminated medical herbs, medical herbs also need this kind of Tracing System based on Information Technology. This study shows current medical herbs tracing ways and RFID(Radio Frequency IDentification) technology trend. As preceding study for future RFID based medical herbs tracing system, this study suggests the building plan and scenario of the Medical Herbs Tracing System. The determination of the main body for sticking RFID Tags is very important to design for RFID Traceability System. In this study, the starting point of information to medical herbs is an inspection agency. The Medical Herbs to product domestically or import moved to an inspection agency. An inspection agency bond the RFID Tags to packing of the Medical Herbs after examining the a basic its component. At the same time inspector give the information of production or importation to the Tags. This Tags are moved for logistical process to end point, the Korean medicine agency. The customer confirmed the traceability and certification information of the Medical Herbs. For success tracing of medical herbs, institutional support and close cooperation between related organizations is necessary besides good system design.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.69-76
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• 2015

With Various signs are installed at roadside to display the message which rather confuse the drivers. The technologies using advanced lighting system and LED have improved the visibility at nighttime but the problems with plural signs have yet to be resolved. In order to solve this problem, LED and the prismatic variable message sign have been applied. But, they have been provided limited information by the display limit. This research conducted to study patent and technical trend of the existing variable message signs to understand the present technology. And, we suggested next generation display to improve providing information. Therefore, we conducted to compare the LED and the OLED by technical and economical literature review. Also, this research conducted test of luminance contrast about the LED and the OLED display in order to understand the possibility of replacing road signs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.202-207
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• 2016

An auxiliary real-time train communications system among drivers, train-traffic controllers and field workers is necessary to share hazard information (i.e. rockfall detection, track maintenance) in low visibility zones (long tunnels and steep curved track). To develop the appropriate communication system, this paper proposes a new way of power line communication using the rail track (Rail - PLC), which has little noise and distortion of attenuation. Therefore, it is important to measure the impedance of the rail and to apply an impedance matching technique to increase the transmission characteristic of the Rail - PLC. This study would evaluate the reflection and the transmission characteristics of the rail using a network analyzer and an impedance matching transformer. The suitable impedance matching ratio was 1:3.28 from the result of back-to-back testing. The results confirmed that the transformer can improve the performance of the transmission signal in Rail - PLC using an impedance matching technique.

• Korean Journal of Cognitive Science
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• v.25 no.1
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• pp.51-71
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• 2014

This paper presents an image enhancement method in real road traffic scenes. The images captured by the camera on the car cannot keep the color constancy as illumination or weather changes. In the real environment, these problems are more worse at back light conditions and at night that make more difficult to the applications of the vision-based intelligent vehicles. Using the existing image enhancement methods without considering the position and intensity of the light source and their geometric relations the image quality can even be deteriorated. Thus, this paper presents a fast and effective method for image enhancement resembling human cognitive system which consists of 1) image preprocessing, 2) color-contrast evaluation, 3) alpha blending of over/under estimated image and preprocessed image. An input image is first preprocessed by gamma correction, and then enhanced by an Automatic Color Enhancement(ACE) method. Finally, the preprocessed image and the ACE image are blended to improve image visibility. The proposed method shows drastically enhanced results visually, and improves the performance in traffic sign detection of the vision based intelligent vehicle applications.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.199-209
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• 2011

In the study of traffic safety, the analysis on factors affecting crash severity and the understanding about their relationship is important to be planning and execute to improve safety of road and traffic facilities. The purpose of this study is to develop a hierarchical binomial logistic model to identify the significant factors affecting fatal injuries and vehicle damages of traffic crashes on freeway. Two models on death and total vehicle damage are developed. The hierarchical structure of response variable is composed of two level, crash-occupant and crash-vehicle. As a result, we have gotten the crash-level random effect from these hierarchical structure as well as the fixed effect of covariates, namely odds ratio. The crash on the main line and in-out section have greater damage than other facilities. Injuries and vehicle damages are severe in case of traffic violations, centerline invasion and speeding. Also, collision crash and fire occurrence is more severe damaged than other crash types. The surrounding environment of surface conditions by climate and visibility conditions by day and night is a significant factor on crash occurrence. On the orher hand, the geometric condition of road isn't.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.168-176
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• 2014

Detecting moving objects from a video sequence is a fundamental and critical task in video surveillance, traffic monitoring and analysis, and human detection and tracking. It is very difficult to detect moving objects in a video sequence degraded by the environmental factor such as fog. In particular, the color of an object become similar to the neighbor and it reduces the saturation, thus making it very difficult to distinguish the object from the background. For such a reason, it is shown that the performance and reliability of object detection and tracking are poor in the foggy weather. In this paper, we propose a novel method to improve the performance of object detection, combining a haze removal algorithm and a local histogram-based object tracking method. For the quantitative evaluation of the proposed system, information retrieval measurements, recall and precision, are used to quantify how well the performance is improved before and after the haze removal. As a result, the visibility of the image is enhanced and the performance of objects detection is improved.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.69-73
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• 2009

Network Virtual Environments (NVEs) is a virtual world where users exchanges messages via network connection. A limited visibility sphere called area of interest (AOI) is used to reduce the load created by the interactions between users. VON-Forwarding model is proposed as an effective methods to reduce network bandwidth in P2P network environment. Vorocast and Fibocast originated from Von-forwarding resolves the problems to receive the same messages repeatly. In this paper, We proposed an Extended Volocast scheme to improve the problem not to get consistency except a limited area near to the center of AOI. The proposed scheme maintains the consistency about the broad area into AOI by adjusting geometrical series $2^X$. We perform simulation experiments to show that the proposed scheme provide better performance compared to the other schemes.