• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.117-120
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• 1991

Cracks of concrete structure must be analyzed and estimated synthetically in order to have a maintenance and to insure the safety and the durability of structure. Concrete cracks have to be surveyed with respect to depth, width, shape and direction etc, but crack depth among these items is not measured easily. Occasionally, it needs to measure the crack depth of concrete structure for the purpose of evaulating the safe capacity and the necessity of repair. Therefore, this research is performed to verify the applicability and the accuracy of Ultra-sonic Pulse Velocity Technique(Tester), in non-destructive testing methods of concrete crack depth.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.537-538
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• 2011

본 논문에서는 전동 휠체어를 이용하여 이동할 때 안전운전을 위한 반 자율 보조 장치를 제안한다. 제안된 전동 휠체어 보조 장치는 장애물 감지를 위한 초음파 센서와 현재 방향과 위치를 확인하기 위한 엔코더를 사용하여 이동시 발생할 수 있는 안전사고를 미연에 방지할 수 있도록 설계하였다.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2492-2494
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• 2005

This study designed on the standard calibration facility for calibration about radar type, ultra-sonic type and floating type. We reviewed calibration facilities, analysis any problems, and proposed optimal plan which uses EDM and electrical level meter.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.434-439
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• 1993

This paper present a sensor based obstacle avoidance method which is based on a VFH(Vector Field Histogram) method. The basic idea of obstacle avoidance is to find a minimum obstacle direction and distance. From the minimum sonar index and the target direction high level system determine steering angle of mobile robot. The sonar sensor system consists of 12 ultra sonic sensor, and each sensor have its direction and safety value. This method has advantage on calculation speed and small memory. This method is implemented on indoor autonomous vehicle'ALiVE-2'.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.543-547
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• 2005

In this paper, we designed a intelligent autonomous driving robot by using Fuzzy algorithm. The object of designed robot is recognition of obstacle, avoidance of obstacle and safe arrival. We append a suspension system to auxiliary wheel for improvement in stability and movement. The designed robot can arrive at destination where is wanted to go by the old and the weak and the handicapped at indoor hospital and building.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.288-288
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• 2000

Reactor vessel is one of the most important equipment with regard to the safety of nuclear power plant. Thus nuclear regulation requires its periodical examination by certified inspection experts. Conventional reactor inspection machines are obsolete, hard to handle, and very expensive. To solve these problems we developed robotic reactor vessel inspection system which are small, easy to use for inspection, cost effective, and convenient in operation. This paper describes the main features of Main Control System which is one part of robotic inspection equipment we developed.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.279-288
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• 2011

• Journal of the Korea Concrete Institute
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• v.19 no.1
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• pp.75-81
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• 2007

Percentage that aggregate of materials that concrete composed about $70{\sim}80%$ of whole volume, therefore influence that quality of aggregate gets in concrete characteristics are very important. Schmidt hammer and ultra-sonic velocity method are commonly used for crushed sand concrete compressive strength test in a construction field. At present, various equations for prediction of strength are present, which have been used in a construction field. The purpose of this study is to evaluate the correlation between prediction strength by present equations and destructive strength to test specimen, and find out which is a suitable equation for the construction site, a strength test was carried out destructive test by means of core sampling and traditional test. The experimental parameters were concrete age, curing condition, and strength level. It is demonstrated that the correlation behavior of crushed sand concrete strength in this study good due to the perform analysis of correlation between core, destructive strength and non-destructive strength.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.12
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• pp.996-1001
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• 2005

Recently, with the development of service robots and with the new concept of ubiquitous world, the position estimation of mobile objects has been raised to an important problem. As pre-liminary research results, some of the localization schemes are introduced, which provide the relative location of the moving objects subjected to accumulated errors. To implement a real time localization system, a new absolute position estimation method for a mobile robot in indoor environment is proposed in this paper. Design and implementation of the localization system comes from the usage of active beacon systems (based upon RFID technology). The active beacon system is composed of an RFID receiver and an ultra-sonic transmitter: 1. The RFID receiver gets the synchronization signal from the mobile robot and 2. The ultra-sonic transmitter sends out the traveling signal to be used for measuring the distance. Position of a mobile robot in a three dimensional space can be calculated basically from the distance information from. Three beacons and the absolute position information of the beacons themselves. In some case, the mobile robot can get the ultrasonic signals from only one or two beacons, because of the obstacles located along the moving path. Therefore, in this paper, as one of our dedicated contribution, the position estimation scheme with less than three sensors has been developed. Also, the extended Kalman filter algorithm is applied for the improvement of position estimation accuracy of the mobile robot.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1897-1904
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• 2006

Home service robot must recognize and build map for indoor and components of the house such as furniture and chair etc. The previous researcher has developed a indoor map building system by using CCD camera and ultra sonic sensor. %no stems have some problem in such a way that (1) a distun resolution can be changed according to the number of pixel when we use a CCD camera system, (2) a measured distance can be decreased when it transmitted to the rubber because of being absorbed the sound energy. This paper represents an intelligent sensor controller of module has been developed by using optic PSD(Position Sensitive Detector) sensor any at a low price. To deduce the switching noise from beam power module and diffused reflection noise, we proposed a heuristic soft filter. The performance of the developed system was compared with ultra sonic sensor system by detecting the indoor wall environment. Some experiments were illustrated for the validity of the developed system.