• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.166-166
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• 2004

운전자 보조시스템에는 적응순항제어 (adaptive cruise control), 차선변경 (lane change), 충돌경고 (collision warning), 충돌회피 (collision avoidance), 및 자동주차 (automatic parking) 등이 있다. 이런 운전자 보조시스템은 어떤 목적을 가지고 있다. 운전자의 부담을 줄이고 안전을 위하여 차량의 주행방향에 있는 장애물이나 차량을 감지하여 차량간의 안전거리론 유지하고 자동차가 일정 속도를 유지하도록 한다. 운전자 보조시스템의 효율은 센서들로부터 얻어진 정보의 해석에 달려있다.(중략)

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.526-528
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• 2022

실외 자율주행 청소 로봇을 위한 인공지능기반 자율주행 시스템을 개발하였다. 개발된 시스템은 ROS(Robot Operationg System) 기반으로 이루어졌으며, 3D 라이다와, 초음파 센서를 활용하여 주변의 장애물을 감지하고 GPS와 영상을 활용하여 로봇의 위치 인식을 하여 자율 주행을 진행하였다. 자율주행 실험결과 영상과 RTK-GPS를 사용하여 정해진 경로를 ±20cm이내의 오차를 가지고 추종하면서 청소를 진행하였다.

• Journal of KIISE:Software and Applications
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• v.36 no.4
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• pp.291-297
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• 2009

This paper introduces an electronic travel aid, named SmartWand, which detects obstacles using a ultrasonic sensor. In addition to obstacle detection, the SmartWand senses color information of objects and the environmental brightness. It is designed to be attached to a ordinary white cane in order to detect the obstacles at head-hight which cannot be covered by the cane. We have improved the first version of the SmartWand based on a user evaluation. The second version is much lighter and smaller than the previous one. It has been enhanced by two new functions. The SmartWand eliminates impact errors due to tapping the ground using a moving average filtering algorithm and restricts the detection range to the path in the moving direction using an acceleration sensor. We have tested these functions in various environments to determine the parameters for these functions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.6
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• pp.535-542
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• 2011

The Global Navigation Satellite System(GNSS) is being utilized in numerous applications. The research for autonomous guided vehicles(AGVs) using precise positioning of GNSS is in progress. GNSS based AGVs is useful for setting driving path. This AGV system is more efficient than the previous one. Escipecially, the obstacle is positioned the driving path. Previcious AGVs which follow marker or wires laid out on the road have to stop the front of obstacle. But GNSS based AGVS can continuously drive using obstacle avoidance. In this paper, we developed collision avoidance system for GNSS based AGV using laser scanner and collision avoidance path setting algorithm. And we analyzed the developed system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.11
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• pp.1653-1659
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• 2022

Virtual reality content provides users with a high sense of immersion by using HMD devices. However, while wearing the HMD device, it is difficult to determine the user's location or distance from obstacles, resulting in injuries due to physical collisions. In this paper, we propose a reminder module to prevent accidents by notifying the risk of collision with obstacles while wearing the HMD device. The proposed module receives the user's state from the acceleration and gyro sensor and determines the motion that is likely to cause a collision. If there is an obstacle in the expected collision range, a buzzer sounds to the wearer. As a result of the experiment, the accuracy of obstacle detection in the state of wearing the HMD was 86.6% in the 1st stage and 83.3% in the 2nd stage, confirming the performance of the accident prevention reminder.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.579-585
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• 2008

Recently, many researches on autonomous mobile system have been proposed, which are possible to recognize its surrounding environment and navigate to destination without supervisor's intervention. Various sensors are mounted on the autonomous systems in order for the systems to move to destination safely without any accident. In this paper, we design an ontology-based autonomous system mounted laser distance sensors and cameras, and propose a method to conceptualize sensing information. We show the validity of the proposed method through the experiments of the system's navigation.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.149-156
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• 2008

SLAM(Simultaneous Localization and Mapping) system is to find a global position and build a map with sensing data when an unmanned-robot navigates an unknown environment. Two kinds of system were developed. One is used distance measurement sensors such as an ultra sonic and a laser sensor. The other is used stereo vision system. The distance measurement SLAM with sensors has low computing time and low cost, but precision of system can be somewhat worse by measurement error or non-linearity of the sensor In contrast, stereo vision system can accurately measure the 3D space area, but it needs high-end system for complex calculation and it is an expensive tool. In this paper, we implement the SLAM system using a single camera image and a PSD sensors. It detects obstacles from the front PSD sensor and then perceive size and feature of the obstacles by image processing. The probability SLAM was implemented using the data of sensor and image and we verify the performance of the system by real experiment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.287-296
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• 2011

The white stick mainly used for visually impaired person has difficulty in providing location information and effective countermeasures for emergency situations encountered during walking as well as detecting floating obstacles on the ground. In this paper, we propose a machine-to-machine based intelligent walking assistance system for safe and convenient walking of the visually impaired. The proposed system consists of a walking assistance stick used by the visually impaired and a server supporting multiple stick users in remote places through mobile communication networks. The stick equipped with ultrasonic sensors, GPS(global positioning system) receiver and vibrator not only detects floating obstacles, but also offers stick users with present location identification utilizing a text-to-voice conversion technology. Besides providing geographic information, the server notifies the emergency locations of users to guardian and aid agency, and it provides log information during walking such as the place, time and the number of accidents. Test results with a developed prototype system have shown that the system properly performs the functions and satisfies overall system performance.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.494-500
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• 2002

본 연구의 목적은 DGPS와 자이로 센서를 장착하여 무인으로 콤바인을 직선주행, 선회 및 곡선주행, 직진주행 중 1 m 오프셋(offset) 주행시켰을 때, 무인 자율주행의 성능을 분석하고 개선하는데 있다. 콤바인의 무인자율주행 시스템은 콤바인의 현재위치를 인식하고, 주행하고 있는 콤바인의 주행방향을 감지하여 미리 설정된 경로를 따라 자율적으로 주행하며, 주행 중에 장애물이 검출되면 정지할 수 있도록 개발하였다. 콤바인의 무인 자율주행시스템은 DGPS의 입력 신호로부터 콤바인의 현재위치를 결정하고, 자이로 센서의 입력신호로부터 주행방향을 알 수 있다. 또한 장애물의 감지를 위한 초음파 센서, 콤바인의 주행방향을 조정하는 유압 작동부, 좌.우의 조향레버를 조정하는 서보모터 시스템, 마이크로 컴퓨터로 구성된 제어기와 입출력 인터페이스로 구성되어 있다. 콤바인 자율주행시스템의 프로그램은 DGPS 신호, 자이로 센서 등을 수신하는 수신 프로그램, DGPS 신호등으로부터 관련 변수들을 분석하여 콤바인의 조향수준을 결정하고, 유압실린더 등을 제어하는 제어 프로그램과 콤바인의 이동경로를 저장하는 저장 프로그램으로 구성되어 있다. 콤바인의 무인주행 실험결과 RMS 오차는 50 m 직선주행에서 7.52 cm, 20 m 직선주행 후 1 m 오프셋 된 30 m의 직선주행에서 21.85 cm, 20 m 직선주행 후 90$^{\circ}$선회하여 25 m 직선주행에서 7.55 cm, 반지름 23 m의 원주 사분면 곡선주행에서는 25.98 cm로 각각 나타났다. 소 구획의 포장에서 벼는 가로 방향으로 25~30 cm, 세로 방향으로 15~20 cm의 간격으로 심어져 있다. DGPS 신호에 의한 위치 결정을 할 때 자체 오차 10 cm를 고려하여도 콤바인이 직선구간 및 선회구간을 주행하며 수확작업이 가능함을 알 수 있었다. 그러나 곡선구간에서는 최대오차가 65.5 cm로 매우 크게 나타나, 콤바인을 무인 자율주행으로 수확하기에는 어려움이 있는 것으로 나타났다. 실제 포장은 이론적인 완전한 직선보다는 작은 굴곡이 있는 곡선의 형태가 이루어져 있으므로 주행 오차를 감소하기 위해서는 기계시각을 이용하면 보다 정밀한 조향을 이룰 수 있을 것으로 예상된다. 포장에서 DGPS 신호, 자이로 센서 등을 이용한 콤바인의 무인주행 장치는 무인 수확작업을 위한 가능성을 보여주었고, 일부의 센서의 기능을 개선하면 만족한 성능을 나타낼 수 있을 것으로 판단된다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.1
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• pp.9-18
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• 2010

Our country has so large mountain area that the tunnel construction is inevitable and the need of incident detection that provides safe management of tunnels is increasing. In this paper, we suggest a tunnel incident detection system using computer vision techniques, which can detect the incidents in a tunnel and provides the information to the tunnel administrative office in order to help safe tunnel operation. The suggested system enhances the processing speed by using simple processing algorithm such as image subtraction, and ensures the accuracy of the system by focused on the incident detection itself rather than its classification. The system is also cost effective because the video data from 4 cameras can be simultaneously analyzed in a single PC-based system. Our system can be easily extended because the PC-based analyzer can be increased according to the number of cameras in a tunnel. Also our web-based structure is useful to connect the other remotely located tunnel incident systems to obtain interoperability between tunnels. Through the experiments the system has successfully detected the incidents in real time including dropped luggage, stoped car, traffic congestion, man walker or bicycle, smoke or fire, reverse driving, etc.