• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.8
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• pp.62-69
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• 1999

This paper presents a vision-based real-time traffic surveillance system. Current research in machine vision applied to traffic is due to its potential for more powerful process, its flexibility and its lower cost. Our traffic surveillance system consists of FPA and TSM on the Internet. The FPA provides image data, vehicle speed and vehicle density for the TSM. Traffic parameters, the vehicle speed and density, are extracted over many frames using differences between the sampling points of a background image and those of incoming frames. The FPA works by just processing groups of pixels without any understanding of the image. Although this system has an accuracy limitation, it can be used in applications requiring an approximate vehicle density and vehicle speed in real-time.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.692-699
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• 2008

This paper describes optimal operation method using recognition of walker's will for a robotic walker. Recently, walking aid system has been required according to the increase of elder and handicapped person. However, most of walking aid system don't have actuator for its movement. Unfortunately, standard frames have weakness for the movement to upward/download direction of slope. So, active type walking aids are interested, but it is not easy to control. In this paper, we adapt user's will system that can recognize walking direction and speed. First, FSR(Force Sensing Register) is applied to measure user's will to walk. And then, fuzzy algorithm is used for determining optimal wheel velocity and direction of the walking aid. From the result, walking aid can move smoothly and safely following the user's will. The walking aid can help user to walk more optimally. Here, all the processes are verified experimentally in the real world.

• Journal of Advanced Navigation Technology
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• v.23 no.3
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• pp.228-236
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• 2019

Recently, multi-sensor integration techniques have been actively studied to obtain reliable and accurate navigation solution in GPS (Global Positioning System)-denied harsh environments such as urban canyons, tunnels, and underground roads. In this paper, we propose a low-cost ultrasonic-speedometer utilizing the characteristics of the ultrasonic propagation. An efficient integrated INS (inertial navigation system)/ultrasonic-speedometer navigation system is also proposed to improve the accuracy of positioning in GPS-denied environments. To evaluate the proposed system, car experiments with field-collected measurements were performed. By the experiment results, it was confirmed that the proposed INS/ultrasonic-speedometer system bounds the positioning error growth effectively even though GPS signal is blocked more than 10 seconds and a low-cost MEMS IMU (micro electro mechanical systems inertial measurement unit) is utilized.

• Computational Structural Engineering
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• v.7 no.3
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• pp.83-93
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• 1994

To design and study the dynamic performance of safety structures, crash tests are needed. Method to get the angular accelerations at the time of impact by integating the Euler equations are introduced. Numerically stable 9-array system contains several 7 and 8-array sub-systems in it. Numerical stability of those latent sub-systems are studied using test files. All of the 8-array subsystems were found to be numerically stable. Six of the 7-array sub-systems were stable and other six of the 7-array sub-systems were unstable. Using this findings fail-safe measurement system can be developed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1398-1404
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• 2009

This paper proposes a vehicle speed detector with anisotropic magnetoresistive (AMR) sensors and addresses experimental results to show the performance of the detector. The detector consists of two AMR sensors and mechanical and electronic apparatuses. The AMR sensor senses disturbance of the earth magnetic field caused by a vehicle moving over the sensor and then produces an output indicative of the moving vehicle. In this paper, vehicle speeds are calculated by using two AMR sensors built on a board. The speed of a vehicle is calculated by dividing the known distance between the two sensors with the time difference between two output signals from each sensor, captured sequentially while the vehicle is driving over the sensors. Some field tests have been carried to show the performance of the proposed detector and its usefulness.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.691-694
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• 2009

전세계적으로 운전자의 주행시 차선변경이나 정지시 돌발적으로 지나가는 옆차선의 차량을 감시함으로서 교통사고발생율을 대폭 감소시킬 수 있기 때문에 많은 시스템들이 개발되고 있다. 그러나 대부분 비젼시스템과 연결되는 고정형 타입으로서 운전자의 시각을 지원해 주는 경우가 많았다. 본 연구에서는 회전형으로 제작되어 사용자가 원하는 대로 감시영역을 축소시키거나 확대시킬 수 있는 방식으로서 사각지대 감지를 위한 서보모터의 회전속도/각도와 초음파센서의 측정거리 및 LED의 ON-OFF 등 각종 파라미터를 조절함으로서 최적의 사양을 선정하였고 시험을 통해 그 타당성을 증명하였다.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2507-2509
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• 2004

지능형 안전자동차에 비전센서를 채택하여 이의 응용시스템을 개발하기 위해서는 궁극적으로 많은 양의 영상데이터를 시스템의 제어목적에 부합하도록 실시간으로 처리하기 위한 노력과 구현하고자 하는 영상처리시스템을 정적인 실내환경과 달리 열악한 환경의 차량에 탑재가 용이하게 하기 위한 소형화의 노력이 요구된다. 본 논문에서 구현된 실시간 영상처리 하드웨어는 에지 연산 등의 반복된 전처리는 FPGA에서 처리하고, 상위단계의 영상처리는 RISC에서 수행하는 구조이다. 구현된 영상처리 하드웨어는 에지정보 기반의 차선정보추출 및 차선이탈 경보알고리즘을 적용하여 그 성능을 평가하였으며, 초당 25프레임 이상의 영상처리를 수행할 수 있는 연산속도를 보여 성공적인 결과를 얻을 수 있었다.

• Journal of the Korean Society for Railway
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• v.8 no.3
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• pp.216-221
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• 2005

In electric motor coaches, the rolling stocks move by the adhesive effort between rail and driving wheel. Generally, the adhesive effort is defined by the function of both the wright of electric motor coach and the adhesive effort between rails and driving wheel. The characteristics of adhesive effort is strongly affected by the conditions between rails and driving wheel. When the adhesive effort decreases suddenly, the electric motor coach has slip phenomena. This paper proposes a re-adhesion control based on disturbance observer and sensor-less vector control. The numerical simulation and experimental results point out that the proposed re-adhesion control system has the desired driving wheel torque response for the tested bogie system of electric coach. Based on this estimated adhesive effort, the re-adhesion control is performed to obtain the maximum transfer of the tractive effort.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.855-858
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• 2001

본 논문에서는 교통 정보 제공 시스템에서 기본적으로 필요로 하는 신뢰성 있는 교통데이터 획득을 위한 교통 영상검지기를 ASIC을 이용하여 효과적으로 구현할 수 있는 구조를 제안한다. 본 논문의 교통 영상검지기에서는 먼저 저가의 CMOS 이미지 센서를 이용하여 영상을 획득한다. 그 다음에 영상을 여러 개의 블록으로 분할하고 블록 매칭 기법을 이용하여 각 블록의 모션 벡터, 즉 각 블록이 다음 프레임에서 어느 방향으로 얼마만큼의 거리를 이동했는지를 추적한다. 그 다음에는 블록들의 모션 벡터로부터 자동차의 속도와 크기를 추출한다. 본 논문의 교통 검지기는 실시간으로 시내 도로나 고속도로에서 실시간으로 교통 정보를 검지할 수 있을 뿐만 아니라 보정이 필요 없어 설치가 매우 간편하다.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.80-85
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• 2011

This paper presents the design of the power-assisted controller for the in-wheel type smart wheelchair by using torque estimation that is predicted by relationship between input voltage and output wheel angular velocity. Nowadays, interest of the moving assistant aids is increased according to the increase in population of the elderly and the handicapped person. However some of the moving assistant aids have problems. For example, manual wheelchair has difficulty moving at the slope, because users lack the muscular strength of their arm. In electric wheelchair case, users should be weak by being decreased muscles of upper body. To overcome these problems, power-assisted electric wheelchair are proposed. Most of the power-assisted electric wheelchair have the special rims that can measure the user's power. In here, the rims have to be designed to install the sensors to measure user's power. In this paper, we don't design the rim to measure the man power. To predict the man power, we propose a control algorithm of the in-wheeled electric wheelchair by using torque estimation from the wheel. First, we measure the wheel velocity and voltage at the in-wheel electric wheelchair. And then we extract driving will forces by using proposed mathematical model. Also they are applied at the controller as the control input, we verify to be able to control in-wheel type smart wheelchair by using simulation.