• Journal of Power System Engineering
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• v.19 no.2
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• pp.33-39
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• 2015

In conducting indoor positioning by code division multiple access using spread spectrum ultrasonic waves, it is required to detect signals under the influence of near-far problem occurred by difference on signal power, caused by distance between transmitter and receiver. For discussing robustness to the problem, we verified measuring accuracy on distance from an experiment on a real space with a hardware device where our proposed method is mounted. The proposed method performs automatic signal detection by setting threshold level dynamically. As an experimental result, measurable distance were improved by the proposed method, and measurement errors were up to 50mm in distances from 1000mm to 6000mm; therefore, enough accuracy to realize self-localization or navigation for autonomous mobile robot or human was obtained.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1810_1811
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• 2009

자율주행 로봇은 자신위치와 장애물의 위치 등 주변 환경을 인지하여 원하는 지점까지 스스로 이동 및 임무 수행이 가능한 로봇 이다. 목표위치를 탐색하기 위하여 GPS 및 초음파 센서를 이용하여 이동 방향 설정 및 주변 장애물 위치를 파악할 수 있도록 하였다. 특히, WLAN을 이용하여 이동 로봇에 대한 위치 정보의 설정 및 위치 데이터의 교신이 가능하도록 하였고 이동로봇을 이용한 실제 실험을 통하여 원하는 위치 탐색과 장애물 회피가 효과적으로 수행됨을 확인한다.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.59-60
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• 2011

요즘 스마트 디바이스의 보급으로 스마트 디바이스를 통한 다양한 정보제공 서비스 또한 빠르게 증가하고 있다. 본 논문에서는 GPS(Global Positioning System) 센서 이용이 제한적인 실내와 같은 좁은 공간에서 스마트 디바이스 통한 내비게이션시 다양한 정보를 제공할 수 있는 실내 조명변화에 강한 마커 인식 방법을 제안한다. 제안 방법은 형태가 비슷한 실내 공간과 조명이 제한적이거나 급격하게 변하는 상황에서 견고하고 정밀한 위치 추적을 통해 정확한 서비스를 제공할 수 있게 해 줄 것이다.

• The Journal of Korea Robotics Society
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• v.2 no.1
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• pp.93-102
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• 2007

It is essential to estimating positions of multiple robots in order to perform cooperative task in common workspace. Accordingly, we propose a new approach of cooperative localization for multiple robots utilizing correlation among GPS errors in common workspace. Assuming that GPS data of individual robot are correlated strongly as the distance among robots are close, it is confirmed that the proposed method provides improved localization accuracy. In addition, we define two operational parameters to apply proposed method in multiple robot system. With mentioned two parameters, we present a practical solution to accumulated position error in traveling long distance.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.527-529
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• 2006

In this paper, we find a robot's path using a Virtual Reality Modeling Language and overlay vision. For correct robot's path we describe a method for localizing a mobile robot in its working environment using a vision system and VRML. The robt identifies landmarks in the environment, using image processing and neural network pattern matching techniques, and then its performs self-positioning with a vision system based on a well-known localization algorithm. After the self-positioning procedure, the 2-D scene of the vision is overlaid with the VRML scene. This paper describes how to realize the self-positioning, and shows the overlap between the 2-D and VRML scenes. The method successfully defines a robot's path.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.446-448
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• 1994

This paper proposes some dynamic navigation strategy for a mobile robot among multiple moving obstacles. The control force of the robot which consists of repulsive and attractive force is based on the artificial potential field. The artificial potential fields is derived with position or(and) velocities of the objects. The simulation results shows the properties of the proposed strategies.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.164-170
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• 2011

This paper proposes a novel monocular vision-based SLAM (Simultaneous Localization and Mapping) method using both position and orientation information of ceiling lamps. Conventional approaches used corner or line features as landmarks in their SLAM algorithms, but these methods were often unable to achieve stable navigation due to a lack of reliable visual features on the ceiling. Since lamp features are usually placed some distances from each other in indoor environments, they can be robustly detected and used as reliable landmarks. We used both the position and orientation of a lamp feature to accurately estimate the robot pose. Its orientation is obtained by calculating the principal axis from the pixel distribution of the lamp area. Both corner and lamp features are used as landmarks in the EKF (Extended Kalman Filter) to increase the stability of the SLAM process. Experimental results show that the proposed scheme works successfully in various indoor environments.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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• pp.400-405
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• 2009

A new method for the catadioptric omnidirectional stereo vision with single camera is presented in this paper. The proposed method uses a concave lens with a convex mirror. Since the optical part of the proposed method is simple and commercially available, the resultant omnidirectional stereo system becomes versatile and cost-effective. The closed-form solution for 3D distance computation is presented based on the simple optics including the reflection and the reflection of the convex mirror and the concave lens. The compactness of the system and the simplicity of the image processing make the omnidirectional stereo system appropriate for real-time applications such as autonomous navigation of a mobile robot or the object manipulation. In order to verify the feasibility of the proposed method, an experimental prototype is implemented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.214-220
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• 2002

If neither a map, nor geographic-information processing equipment or a micro browser was prepared in a move terminal in the case of the old system, traffic guidance processing was not able to be carried out. Even if this system was required and did not carry out above -mentioned equipment or an above-mentioned system with a move terminal or a cellular phone, it could be made to do it. Traffic information guidance processing is possible to be completed only by the general telephone or electronic mail transmission.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.327-332
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• 2007

모바일폰의 컨버전스가 가속화됨에 따라 사용자가 습득해야 할 정보량이 증가하였고, 사용자들이 이를 이용하기 위하여 학습과 숙련의 과정을 거쳐야 하는 부담이 발생하게 되었다. 모바일폰의 주 사용자층인 20-40대 외에 10대와 50대 이상의 이동전화 이용률이 꾸준히 증가하여 실버폰과 키즈폰 시장이 형성될 조짐을 보이고 있지만, 제조사에서는 획일적인 인터페이스 디자인만을 제공하여 다양한 사용자 층의 요구와도 서로 맞지 않고 있다. 이에 본 연구에서는 모바일폰의 휴먼인터페이스 요소 중 메뉴요소에 해당하는 메인메뉴의 네비게이션 방식에 중점을 두어 각 사용자 유형별로 사용성을 측정하였다. 국내외 모바일폰 제조사에서 2006년 출시된 제품에서 메인메뉴 네비게이션 방식을 추출하여 8가지로 분류하였으며, 이를 토대로 플래시 기반의 시뮬레이터를 제작하여 사용성 측정에 이용하였다. 모바일 사용성 평가를 위한 요인을 중심으로 10대부터 60대 이상의 다양한 사용자를 대상으로 시뮬레이터 사용을 관찰하여 분석하였으며 또한 기존에 사용하고 있는 모바일폰 기종을 고려하여 설문지로 사용성에 대한 만족도를 평가하는 방식도 병행하였다. 본 연구에서는 사용자 유형별로 사용성이 높은 인터페이스를 선별하고 사용자의 개성과 선호도를 고려한 선택적인 UI 개발방향을 제안하였다.