• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.2
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• pp.87-93
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• 1993

This paper is described on the positioning accuracy of GPS which has observed from November. 1991 to September, 1992 in Korean southeast coast. The main results give as follows. 1) A daily variance of positioning error is irregularly, and the average error of the latitude and the longitude are 15.1m, 22.7m respectively. 2) The usable satellites in Korean southeast coast from Panggojin to Chisepo are SV satellite number 2, 3, 11～21, 23～26 and sv 28, of all these sv 3, 16, 17, 23, 24 and 26 can be observed in all the area. 3) A circle of the average radius enclose 95% of the measurement points are 72.9m and the average shift distances from standard position are 34.6m. 4) The variation of PDOP(HDOP) at each measurement points are coincide with the one of distance error.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.53.2-53
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• 2001

The Non-Contact Optical Sensor using the Hologram Laser for CD Pickup was developed to measure a shape of transparent objects and shown a good performance. Therefore the problems caused by the contact sensor are solved by using the Non-Contact Sensor. The Non-Contact Sensor has to move toward the objects and obtain the Focus Error Signal to measure a position of transparent objects. However, if the distance between the sensor and the object is shorter than the working distance of the objective lens, the sensor will be collided against the objects. In this paper we proposed a new algorithm to estimate the start position of the Focus Error Signal to solve the problems of collision between the sensor and the objects. In addition, we verified that the algorithm is free from the collision in the real time measurement.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.15-21
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• 1997

In this paper, a self-activated cable spooling system for seaborne winch is developed . The system consists of a hydraulic servo driving unit and a cable position measurement mechanism. To realize the cable spooling system, it is carried out the mathematical modelling of the system and designed the proportional controller through the system aalysis and the simulation. The cable spooling system is tested and evaluated to validate the performance of the controller. The test results shows a good traceability of the cable spooling system under disturbance of cable tension.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.295-306
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• 2002

The purpose of this study was analysis inter relative the ball velocity and isotonic torque of shoulder joint. The subject were twelve overthrow pitcher of professional baseball player. The measurement was used Cybex 6000. The results of this study were as follows : 1. As the siting position of maximal adduction torque of dominant, A group was higher than B group. As the non-dominant, B group was higher than A group for improved angular velocity. There is no significance difference between group. 2. As the siting position of maximal abduction torque of dominant and non-dominant, B group was higher than A group for all measurement. There is no significance difference between group. 3. As the layed position of maximal internal torque of dominant, A group was higher than B group. As the non-dominant was just higher at $180_{\circ}$/sec than B group, B group was higher at $60_{\circ}$/sec and $300_{\circ}$/sec than A group. There is no significance difference between group. 4. As the layed position of maximal external torque of dominant and non-dominant, A group was more higher than B group for all measurement. There is no significance difference between group. 5. As the standing position of maximal internal torque of dominant, A group was just higher at $60_{\circ}$/sec than B group, B group was higher at $180_{\circ}$/sec and $300_{\circ}$/sec than A group. As the non-dominant, B group was higher than A group. There is no significance difference between group. 6. As the standing position of maximal external torque of dominant, A group was higher $60_{\circ}$/sec and $180_{\circ}$/sec than B group. But B group was higher $300_{\circ}$/sec than A group. As the non-dominant, B group was higher than A group. There is no significance difference between group.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.2
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• pp.304-310
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• 2010

Chronic pain and herniated disk is a common disease that 80% of adults are experienced. There diseases rates of caused by the physical shock, such as the traffic accident, and the accidental fall is about 10%. And the most of these diseases is caused by having habitual incorrect position. People know that incorrect position would cause to accumulate continuous stress, but it is not easy to correct position. Because it does not recognize incorrect position repeated habitual consequently. This system collects data of user position after sensors that could measure position attach on use and presumes correct position used by position presumption algorithms. Its system purpose is continuing incorrect position could be aware to user and lead to change to correct position to prevent habituation of incorrect position. If habitual of correct position continues through accurate measurement and repeating cognitive learning, it would help for children and chronic patience.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.682-688
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• 2000

To improve the performance of a flexible robot arm one of the important things is the vibration displacement measurement of a flexible arm. Many types of sensors have been used to measure it, The most popular has been strain gauges which measures the deflection of the beam,. Photo sensors have also been for detecting beam displacement and accelerometers are often used to measure the beam vibration. But the vibration displacement can be obtained indirectly from these sensors. In this article a vision sensor is used as a displacement sensor to measure the vibration displacement of a flexible robot arm. Several schemes are proposed to reduce the image processing time and increase its accuracy. From the experimental results it is seen that the vision sensor can be an alternative sensor for measuring the vibration displacement and has a potential for on-line tip position control of flexible robot systems.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.222-231
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• 2010

This paper presents numerical analysis of measurement errors of ground electrode using the fall-of-potential method. In order to analyze ground resistance error according to the positions of auxiliary probes, firstly, national and international standards were researched. Secondly, numerical ground resistance error of hemispheric electrode was analyzed according to the locations of auxiliary probes and the angle between probes. Then, error-reduced positions of auxiliary probes were shown according to the distance to auxiliary current probe versus ground electrode size. Finally, error compensation method was presented. The results presented in this paper provide useful information regarding ground resistance error of alternative positions of auxiliary probes in case that the auxiliary probes could not be located at the proper position in such cases as there are buildings, roadblock or underground metallic pipe at that position.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.289-295
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• 2015

This paper describes a ground monocular vision-based measurement algorithm measuring relative range and position of aircraft using the information of wingspan and optical parameters for the camera. A technique obtaining an aircraft image is also described in this paper. This technique can be used as external measurement for autonomous landing instead of ILS. To verify the performance of these algorithms, flight experiment is performed using light sport aircraft with GPS and monocular camera. Finally we obtained the reasonable RMSE of 1.85m is obtained.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.742-747
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• 2004

Hard disk drives (HDD) in computer are used extensively as data storage capacity. PIV measurement system was used fur 2-dimensional visualization of the unsteady flow between co-rotating disks in air both with a shroud and both with a actual-like case. Geometric parameters are gap height (H) between disks in the case of shroud. The lobe- structured boundary between inner region and outer region was visualized, and the number of dominant vertices was determined clearly. It is found from flow visualization that the number of vortex cells can be correlated with Reynolds number based on H which is defined as R $e_{H}$ =ΩRH/v ranging from 7.96$\times$10$^2$ to 1.43$\times$10$^4$, and decreases as the disk speed increases. In the case of a actual-like case, the boundary between inner region and outer region appears cleary when head position located at outer diameter with no damper. It is detected with a case of head position middle diameter that the tip wake is generated behind HGA using PIV measurement and calculation.n.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4418-4437
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• 2017

In this paper a three-phase secure compressive sensing (CS) and received signal strength (RSS) based target localization approach is proposed to mitigate the effect of malicious node attack. RSS measurements are first arranged into a group of subsets where the same measurement can be included in multiple subsets. Intermediate target position estimates are then produced using individual subsets of RSS measurements and the CS technique. From the intermediate position estimates, the residual error vector and residual error square vector are formed. The least median of residual error square is utilized to define a verifier parameter. The selected residual error vector is utilized along with a threshold to determine whether a node or measurement is under attack. The final target positions are estimated by using only the attack-free measurements and the CS technique. Further, theoretical analysis is performed for parameter selection and computational complexity evaluation. Extensive simulation studies are carried out to demonstrate the advantage of the proposed CS-based secure localization approach over the existing algorithms.