• Journal of Korea Game Society
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• v.4 no.2
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• pp.13-20
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• 2004

We have been interested in solving escapee-chaser game. In this game, with avoiding chaser, the escapee must escape from given male. The winning strategies of the escapee are driving the chaser to an intended place and closely evading from chaser by using some walls. According to our experience, some stages of the game are too difficult to solve manually. So we take the model checking method to get a solution of the game. Because the model checking with breadth fist search manner exhaustively searches the all state space of the game, the solution using model checking is best solution, shortest path. Fortunately, during the process of finding solution path, the state space explosion problem didn't occur, and the results of the game solving was applied to embedded system, Lego Mindstorm. Two agents, escapee and chaser, were implemented into robots and several experiments conformed the correctness of our solution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1306-1312
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• 2017

The route request (RREQ) packet is selectively re-broadcasted in the routing protocols that improve the broadcast storm problem of the ad-hoc on-demand routing protocol (AODV). However, in a low node density scenario, the connectivity of these selective rebroadcast schemes becomes less than that of the AODV. In order to clarify the requirements of these selective re-broadcast routing protocols, it is necessary to investigate the relationship between the node density and the connectivity. In this paper, we drive a probability to preserve the connectivity of the GAODV at an intermediate rebroadcast node. In addition, we present an intuitive method to approximate the end-to-end connectivity of the GAODV. We draw the required node density to guarantee the connectivity of 0.9 and 0.99 through computer simulations, and verify the validity of the derived theoritical connectivity by comparing with the simulation results.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.162-172
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• 2011

This paper proposes embedded System of two wheeled inverted pendulum robot designed by model based design method, using MATLAB/SIMULINK and LEGO NXT Mindstorms. At first, stability and performance of controller is verified through modeling and simulation. After that direct conversion from simulation model to C code is carried and effectiveness of controller is experimentally verified. Two wheeled inverted pendulum robot has basic function about autonomous balancing control using principle of inverted pedulum and it is also possible to arrive at destination. In this paper, state feedback controller designed by quadratic optimal control method is used. And quadratic optimal control uses state feedback control gain K to minimize performance index function J. Because it is easy to find gain, this control method can be used in the controller of two wheeled inverted pendulum robot. This proposed robot system is experimentally verified with following performances - balancing control, disturbance rejection, remote control, line following and obstacle avoidance.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.190-205
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• 2017

The purpose of this study was to analyze domestic research trends of software education using robot, and find out implications for studies. The 108 articles from 2006 to 2016 in terms of software education using robot were analyzed. Results showd that there has been the growing number of articles, the development research was most frequently used in those studies. And most articles were studies on elementary school students. There used programming such as Scratch, NXT-G etc. and utilized robot likes Mindstorms series, Picocriket etc. Also, there applied to PBL, CPS etc. on software education using robot. Finally, Positive results were shown in learners' cognitive and affective domain. This research has an significance in terms of verifying the educational implications of software education using robot, and offering the direction of software education using robot in the future.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.42-53
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• 2020

With the development of social network services, graph structures have been utilized to represent relationships among objects in various applications. Recently, a demand of subgraph matching in real-time graph streams has been increased. Therefore, an efficient approximate Top-k subgraph matching scheme for low latency in real-time graph streams is required. In this paper, we propose an approximate Top-k subgraph matching scheme considering data reuse in graph stream environments. The proposed scheme utilizes the distributed stream processing platform, called Storm to handle a large amount of stream data. We also utilize an existing data reuse scheme to decrease stream processing costs. We propose a distance based summary indexing technique to generate Top-k subgraph matching results. The proposed summary indexing technique costs very low since it only stores distances among vertices that are selected in advance. Finally, we provide k subgraph matching results to users by performing an approximate Top-k matching on the summary indexing. In order to show the superiority of the proposed scheme, we conduct various performance evaluations in diverse real world datasets.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2975-2982
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• 2010

In this paper, embedded control system of segway robot using model based design is presented. Design of control program in embedded system can be implemented simply and easily by model based design method using MATLAB/SIMULINK. Segway robot is consisted of a NXT Mindstorms controller, two DC servo motors, a ultrasonic sensor, a gyro sensor, and a light sensor. It is a unstable nonlinear system and has a control problem of body pitch angle. So controller of segway robot is designed using state feedback LQR control. It is confirmed through design and experiment of controller that the model based design method, that is not depend on target processor, has merits compared with the text based design in aspects such as a program development, an error detection/modify, and an insight of software structure.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.146-151
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• 2009

A reward of the work which used physical computing in fields artistic modern installation is becoming large. But the example that used a robot cannot try to easily look it up on a tool of the drawing which isn't robot use for interaction. I will mention it about a user and a drawing system design and the developmental process which I can communicate with at these papers. I used a Mindstorm NXT system to have been said in Lego companies in the robot which composed working environment, and I classified it to virtual environments that I forecasted environmental actual drawing this, and I did simulate. I used an Icommand library to control a NXT system, and drawing used a processing library in actual environments for the purpose of in order to to express to virtual environment. I got image information, and I expressed to a vector method SVG file to bases for line drawing. This system can have already made it according to demand of a user as real-time communication is possible by bluetooth working together. These figures can work to one performance not being stopping to the results of already in processes doing drawing.

• Journal of The Korean Association of Information Education
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• v.11 no.2
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• pp.231-241
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• 2007

With a focus on LabView language to program Lego Mindstoms Robot in afterschool class to help children develop their special ability and aptitude. The purpose of this research was to make proposal for programming learning method using a robot as an algorithm learning tool to improve creative problem solving ability. To do this, robot programming training program in the amount of 30th period and teaching aids thereof were developed, and 6th grade primary school children were taught up to 30th period, then after, they were evaluated accordingly. Results from analysis of evaluation of achievement level with a focus on outcomes according to each period revealed that learners understood most of contents of curriculum. In view of such results from evaluation, it is judged that the curriculum as well as teaching aids that devised and created have been constituted in order that school children will be able to have developed a shared understanding of their learning sufficiently, and to put it into practice easily. Through these hands-on experiences in the course of researches, researcher could have confirmed the possibility of success for robot-programming training class as new creative algorithm learning tool in the primary school curriculum.

• Journal of The Korean Association of Information Education
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• v.17 no.3
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• pp.347-355
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• 2013

A robot assisted education has advantages to increase the students' flow degree. Especially, when we teach programming with robots we take advantages that the students can easily understand the programs because they are interested in the robots and they can see the movement of the robots. However, it is difficult to teach programming to meet our purposes because the students have reluctances to the robot programming with sensors and they take a lot of time building the robots. Therefore, in this paper I analysed the patterns of the robot programming and propose new robot programming education methods that the students need not to care to the sensors. According to this methods, we can teach the robot programming efficiently because we reduce the time to build and programming the robots.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.207-214
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• 2011

In this paper, using Zigbee-based wireless sensor networks and Lego MindStorms NXT robot, a remote monitoring and navigation system for mobile robot has been developed. Mobile robot can estimate its position using encoder values of its motor, but due to the existing friction and shortage of motor power etc., error occurs. To fix this problem and obtain more accurate position of mobile robot, a ultrasound module on wireless sensor networks has been used in this paper. To overcome disadvantages of ultrasound which include straightforwardness and narrow detection coverage, we rotate moving node attached to mobile robot by $360^{\circ}$ to measure each distance from four fixed nodes. Then location of mobile robot is estimated by triangulation using measured distance values. In addition, images are sent via a network using a USB Web camera to smart phone. On smart phones we can see location of robot, and images around places where robot navigates. And remote monitoring and navigation is possible by just clicking points at the map on smart phones.