• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.45-56
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• 2010

This paper reports a new mechanism for congestion controls. The proposed congestion detection algorithm can be provided with delay and unnecessary energy consumption. Conventional congestion control methods decide congestion by queue occupancy or mean packet arrival rate of MAC layer only, however, our method can perform precise detection by considering queue occupancy and mean packet arrival rate. In addition, the congestion avoiding method according to congestion degree and scheduling method using priority for real time packets are proposed. Finally, simulation results show that proposed congestion detection and control methods outperforms conventional scheduling schemes for wireless sensor network.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.5
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• pp.367-372
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• 2001

This paper proposes a hierachically structured navigation algorithm for multiple mobile robots under unknown dynamic environment. The proposed algorithm consists of three basic parts as follows. The first part based on the fuzzy rule generates the turning angle and moving distance of the robot for goal approach without obstacles. In the second part, using both fuzzy and neural network, the angle and distance of the robot to avoid collision with dynamic and static obstacles are obtained. The final adjustment of the weighting factor based on fuzzy rule for moving and avoiding distance of the robots is provided in the third stage. Some simulation results show the effectiveness of the proposed algorithm.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.457-467
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• 2004

In this paper, a robot is considered as an agent, a structure of robot is presented which consisted by multi-subagents and they have diverse capacity such as perception, intelligence, action etc., required for robot. Also, subagents are consisted by micro-agent($\mu$agent) charged for elementary action required. The structure of robot control have two sub-agents, the one is behavior based reactive controller and action selection sub agent, and action selection sub-agent select a action based on the high label action and high performance, and which have a learning mechanism based on the reinforcement learning. For presented robot structure, it is easy to give intelligence to each element of action and a new approach of multi robot control. Presented robot is simulated for two goals: chaotic exploration and obstacle avoidance, and fabricated by using 8bit microcontroller, and experimented.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.6
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• pp.581-590
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• 2016

This paper proposes an efficient collision avoidance algorithm that a group of RFID readers manage each of their affiliated active RFID tags in a space by establishing wireless network and avoids communication collision between RFID reader to reader and RFID tag to tag, and reader to tag. RF readers operate as wireless network nodes, create synchronous links each other, and can exchange messages. Active tags also are operated communicating each reader devices synchronously, and competing slot position between tags algorithm using unique tag identification number is implemented. Each reader node operates their own reader function different time slot network communication period to prevent collision between readers communication.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.199-201
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• 2003

전력산업의 경쟁도입 환경으로 인한 송전서비스에 대한 증가된 수요를 보여주고 있다. NERC의 1997-2000 신뢰도 평가 보고서에 의하면 과거 10년동안 대부분의 송전시스템 추가는 지역적 보강을 위해 이루어졌다. 전 계통의 시스템 능력을 강화시키는 큰 송전시스템의 증설은 거의 이루어지지 않았다. SPS는 비정상적 계통 상황을 검출하고 미리 계획된 동작을 수행함으로써 비정상적 상황을 회피하여 정상적 계통을 유지하게 한다. SPS는 계통의 송전능력을 증가시키는데 자주 이용된다. 새로운 송전설비 증설의 대안으로 비용면에서 값싼 SPS가 활용되어지는 것이다. SPS가 정확하게 동작한다면 상정사고에 대한 시스템 능력을 매우 향상된다. 그러나 미리 정의된 상황을 검출하는데 실패하거나 미리 계획된 교정동작을 수행하는데 실패한다면 매우 심각한 결과를 초래한다. IEEE-CIGRE 설문조사에서 보여주듯이 SPS 동작 실패는 비용면에서 매우 높은편으로 응답되었다. 따라서 단순 비용 평가를 통해 SPS를 도입을 결정할 수 없다. 경제적 위험 평가를 통해 SPS가 있을때와 없을때의 위험을 평가하여 의사결정에 반영하여야 한다. 본 논문에서는 SPS의 위험을 평가하는 절차를 보여주고 산업에서 SPS 경험들을 소개하도록 한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.587-593
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• 2017

In this paper, we propose a method to solve the difficulties in constructing an environment capable of practical training on the theoretical contents of robot control field. We make a two-wheeled mobile robot with Segway structure using LEGO block. In order to demonstrate the validity of using the developed robot as a practical application of advanced control theory of robotics education such as dynamic system and nonlinear system, the robot takes a stable posture while balancing the change of gravity during running. The results of the experiment are shown. By presenting the results, the robots made using the LEGO block are used for practical training of advanced control theory of robotics. It can be used as a tool.

• Annual Conference of KIPS
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• 2019.10a
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• pp.621-622
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• 2019

본 논문은 도심 환경하에서 운행 가능한 자율주행차량 시스템의 구현 방안에 대해 다루고 있다. 현대자동차가 주최한 2019 대학생 자율주행 경진대회는 도심 환경을 재현한 K-City 에서 열렸고, 도심 환경에서 발생할 수 있는 돌발 장애물 인지, 공사 구간 우회, 교차로 신호등 인지, 사고 차량 회피, 응급 차량에게 차선 양보 및 톨게이트 통과 등의 6 개의 미션을 자율주행차량이 무인운전으로 수행하는 것이었다. 이 대회를 위해 본 연구팀에서 개발한 자율주행 시스템은 리웍된 실제 차량에 탑재되어 대회장의 모든 주행 미션을 성공적으로 수행하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.200-201
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• 2016

Recently, according to era of Internet of Things was opened, various mobile devices connected to the internet using wireless communication. Many IoT devices have limited communication performance. Thus, these devices efficiently forward data using an abbreviated ID method. However, movement of devices causes abbreviated ID confliction, and These conflict degraded network performance. Therefore it is important management of ID conflict. In this paper, we proposed an abbreviated ID conflict management method to improve the efficiency of communication in the dynamic IoT network.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.4
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• pp.266-273
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• 2019

The efficiency and effectiveness of mission performance can be greatly changed according to the operating conditions such as the number of manned aircraft, flight altitude, and so on, in performing search and reconnaissance missions using a large number of small reconnaissance unmanned aerial vehicles. However, it is not easy to determine which operating conditions are most reasonable. Therefore, in this study, we developed an unmanned airplane flight simulation that can detect and identify the target while avoiding collision according to autonomous flight, suggesting a way to derive operating conditions when operating a large number of unmanned aerial vehicles.

• 대한공업교육학회지
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• v.43 no.2
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• pp.79-96
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• 2018

In this study, we look at the effect that the achievement goal of specialized high school students has on academic self-efficacy and the difference in academic self-efficacy depending on achievement goal orientation. The purpose of this research is to help students to efficiently increase their academic self-efficacy, develop research and study life guidance measures to improve negative factors, and select professors and learning methods. To achieve the purpose, survey was conducted with achievement goal orientation measurement tools(26 questions) and academic self-efficacy measurement tools(28 questions) for 745 students of 18 specialized technical high school students in 5 districts. The results of this study are as follows. First, preference to task difficulty and self-controlling efficacy have highly positive correlations with mastery goal orientation and confidence and mastery avoidance goal orientation have highly negative correlations each other. Second, achievement goal orientation form of specialized high school students were divided into 5 forms; 'execution avoidance(34.8%)', 'mastery orientation(20.8%)', 'approach(17%)', 'avoidance competition(14.9%)', and'mastery avoidance(12.5%)'. In preference to task difficulty, 'approach'group showed the highest average point and 'mastery avoidance'showed the lowest average point. The average point of 'approach' group was higher than other groups in confidence, but 'mastery orientation' group showed the highest average point. Through the results of this study, academic self-efficacy makes an effect by a certain direction in accordance with achievement goal orientation and it's necessary to access academic problems differently according to student's goal directivity. Therefore, it's necessary to provide educational method by student type based on explanation about academic self-efficacy of achievement goal orientation of specialized high school students and analysis on achievement goal orientation form.