• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.411-413
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• 2002

In this paper we researched about the ultrasonic cane which aids the blind to walk. We used ultrasonic in recognizing the object and implemented pulse counting method in measuring the distance. The distance measuring system consists of transmitter unit, receiver unit and micro-processor. We used broadband ultrasonic sensors in transmitter unit and receiver unit. The blind is able to recognize the distance between obstacles and himself as it used a vibration system.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.241-245
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• 2003

This paper introduces a method that can derive information about the movement of a spreader and skew in order to drive ALS(Automatic Landing System) in the crane used at a harbor. Some methods that use LDL Corner detectors a kind of 2D Laser scanner sensor or Laser distance measuring units to obtain the information in ALS are used presently. But these have some defects in economic efficiency and performance. Therefore, to correct these defects, we propose a method to acquire the information for the movement of a spreader, skew and sway angle using CCD camera image data and Laser distance measuring unit data.

• Journal of Mechanical Science and Technology
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• v.15 no.10
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• pp.1369-1379
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• 2001

This paper focuses on a development of a sensor system measuring locations of a vehicle to localize a mobile robot while it tracks on the track (location sensor) . Also it focuses on a system configuration identifying the vehicle's orientation and distance from the object while it is stationary at certain station (position sensor) . As for the location sensor it consists of a set of sensors with a combined guiding and counting sensor, and an address-coded sensor to localize the vehicle while moving on the rail. For the position sensor a PSD (Position Sensitive Device) sensor with photo-switches sensor to measure the offset and orientation of the vehicle at each station is introduced. Both sensor systems are integrated with a microprocessor as a data relay to the main computer controlling the vehicle. The location sensor system is developed and its performance for a mobile robot is verified by experiments. The position measuring system is proposed and is robust to the environmental variation. Moreover, the two kinds of sensor systems guarantee a low cost application and high reliability.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.189-198
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• 2021

In this paper, we introduce the software/hardware system that can reliably calculate the distance from sensor to the model regardless of point cloud density. As the 3d point cloud map is widely adopted for SLAM and computer vision, the accuracy of point cloud map is of great importance. However, the 3D point cloud map obtained from Lidar may reveal different point cloud density depending on the choice of sensor, measurement distance and the object shape. Currently, when measuring map accuracy, high reflective bands are used to generate specific points in point cloud map where distances are measured manually. This manual process is time and labor consuming being highly affected by Lidar sparsity level. To overcome these problems, this paper presents a hardware design that leverage high intensity point from three planar surface. Furthermore, by calculating distance from sensor to the device, we verified that the automated method is much faster than the manual procedure and robust to sparsity by testing with RGB-D camera and Lidar. As will be shown, the system performance is not limited to indoor environment by progressing the experiment using Lidar sensor at outdoor environment.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.240-245
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• 2019

This paper is a study result on long distance transmission of underwater acoustic sensor data over cable. The data transceiver is designed using the LVDS (Low Voltage Differential Signaling) transmission scheme, and the jitter characteristics are analyzed by measuring the long distance transmission signal through the cable. In order to reduce the jitter, a pre-emphasis technique is applied to compensate the transmitting signal to be attenuated by long distance transmission, and the transmission characteristics were verified according to the distance.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1100-1109
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• 2006

In this study, two different technologies which can measure temperature simultaneously at many points are introduced. One is to use a thermal sensor cable that is comprised of addressable thermal sensors connected in parallel within a single cable. The other is to use an optic fiber with Distributed Temperature Sensing (DTS) system. The difference between two technologies can be summarized as follows. A thermal sensor cable has a concept of 'point sensing' that can measure temperature at accurate position of a thermal sensor. So the accuracy and resolution of temperature measurement are up to the ability of the thermal sensor. Whereas optic fiber sensor has a concept of 'distributed sensing' because temperature is measured by ratio of Stokes and anti-Stokes component intensities of Raman backscatter that is generated when laser pulse travels along an optic fiber. It's resolution is determined by measuring distance, measuring time and spatial resolution. The purpose of this study is that application targets of two temperature measurement techniques are checked in technical and economical phases by examining the strength and weakness of them. Considering the functions and characteristics of two techniques, the thermal sensor cable will be suitable to apply to the assessment of groundwater flow, geothermal distribution and grouting efficiency within 300m distance. It is expected that the optic fiber sensor can be widely utilized at various fields (for example: pipe line inspection, tunnel fire detection, power line monitoring etc.) which need an information of temperature distribution over relatively long distance.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.453-458
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• 2004

A capacitate sensor is a proper device for measuring high small displacement. General design parameters and procedure are discussed and a test sensor was built to have a measuring range of 100$\mu\textrm{m}$ and a sensitivity about 30nm. This sensor has too opposing electrode of comparably large area and has nominal gap distance about 150$\mu\textrm{m}$. So as to achieve a nano order displacement sensitivity, both sensor and target system have to be considered. This is important for the sensitivity can be achieved by minimizing a system total noise level in electronic type sensor application. Typical performance of the developed sensor is demonstrated in precision moving stage having 0.1$\mu\textrm{m}$ moving resolution.

• Journal of Biosystems Engineering
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• v.23 no.1
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• pp.83-90
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• 1998

In this paper the automatic system for dairy cattle has been desisted such as body temperature measuring unit, feed supplying unit and temperature control unit. Since e disease is strongly related to the body temperature of cattle, early detection of the abnormal temperature would prevent the severe problems which nay occur in dairy farms. An electronic component AD590J is used as temperature sensor for the system, The device is highly robust against the noise since the output signal is the current so it can be applied to a long distance sensing The resolution of signal is 0.1$^{\circ}C$ and the current is 10㎷ Also 12-bit A/D converter is desisted fir interfacing the sensor with a one-chip microprocessor. A temperature measuring experiment using the developed system has been done for measuring the temperature of human beings and the system was proven to be useful for measuring the body temperature of dairy cattle properly. A geared AC motor is used for the feed supplying unit The heater and fm are used as temperature control unit. The feed supplying unit and temperature control unit are well operating in the laboratory experiment.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.836-839
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• 1996

Throughout CGL (Continuous Galvanizing Line) in steel works, zinc-coated steel sheets are produced which are used where long-running corrosion resistivity is required. During the galvanizing process, top dross is created and floated on the zinc pot. Because the dross leaves ill patterns on the coated sheets, a robot system is developed to automatically collect and remove the top dross. It consists of a robot and its carriage system, a pot level sensor, a system controller, and special robot tools. For the first time the level of zinc pot must be measured and fed back to the robot controller to avoid submersion of the robot hand into the hot zinc pot. In this paper, acoustic distance sensor is tested as a candidate for the pot level sensor in the view point of hot environment. Some considerations on the use of the acoustic distance sensor will be denoted.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.118.2-118
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• 2001

This research describes a development of laser distance sensor with precise resolution even in the case that the object surface has some curvature. There are typical two methods in measuring the distance by using laser light source, so called time of flight and optic-triangular methods. Both methods have an advantage and a disadvantage each other. In general, the time of flight method produces wide range of the measurement, but low accuracy. The other method is vice versa. In this research, the optic-triangular methods with one-dimensional CCD cell are proposed to obtain the precise distance measure from the sensor the surface of the curved object ...