• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.336-340
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• 1997

For optimal design of micro stage, we were measured to displacement of piezo-electric transducer that was based on voltage value. And then researchers were analyzed to microstage through FEM with displacement data including voltage value of piezo-electric transducer. For verification of analyzing results, we were gauged on displacement by using Laser-interferometer. And researchers were confirmed to propriety of micro stage design with FEM, were obtained error rate that are 3.5% between measurement results and analyzing results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.920-924
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• 2003

This paper on measurement of curvature radius by the using of laser interferometer and prove. Mean value compared of ball and bearing It is developed program for date creation, and the verification using program. Measurement object center and curvature radius taking of LSC. when it is compared bearing prove with ball prove, the bearing prove can not proper by reason of big uncertainty and If laser setting error decrease, curvature radius get precision radius 10$\^$-5/.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1083-1086
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• 2003

Recently, the study on bearingless motors which integrate both motor and magnetic bearing function in one stator is very active, as many machines have high rotational speed, high precision, smaller size and lighter weight. In this paper, we propose a novel rotary actuator including function of axial bearing using Lorentz force as a preceding research for development of a bearingless motor. As using Lorentz force, this type has some merits such as the linearity of control force, freedom from flux saturation and high efficiency unlike conventional rotary actuators using a reluctance force. This type is cotrolled independently in levitation and rotational directions respectively. It shows by mathematical expression of levitation force and torque in the proposed rotary actuator. And also, the levitation force is generated by magnetic interaction between the magnetic materials and the rotational torque is generated by Lorentz force. Finally. for verification of this proposed system, a prototype is made and some experiments will be performed in the near future.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.158-162
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• 2002

In this paper, the usefulness of a three-dimensional forging simulation technique is verified through its application to process design in rotor pole forging. A simulator, AFDEX3D developed based on the rigid-plastic finite element method and hexahedral elements, is employed. The simulated results of an application example found in a precision forging company are compared with the actually forged ones in detail. It has been verified that the simulation results are in good agreement with the actual phenomena.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.165-165
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• 2003

• The KIPS Transactions:PartA
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• v.19A no.4
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• pp.181-186
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• 2012

The distributed measurement and control system require technology to solve complex synchronization problem among distributed devices. It can be solved by using IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems to synchronize real-time clocks incorporated within each component of the system. In this paper, we implemented the IEEE 1588v2 PTP emulator on BlueScope BL6000A using a delay request-response mechanism to measure clock synchronization.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.788-797
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• 2011

This paper analyzes the accuracy on the approach and landing of aircraft to an airport through comparison with airbase Precision Approach Radar and aircraft track data of DGPS equipped in aircraft. The proposed analysis result could be a basis for verifying the possibility that DGPS can be utilized in Airbase precision approach and landing. Position identification capability of widely used commercial DGPS is fairly accurate on latitude and longitude, while there is a slight error for being used in an airbase accurate approach and landing of Category I precision when it comes to altitude. Thus, we tested accuracy by analyzing actual flight track data of high performance aircraft to verify the accuracy of the airbase approach and landing using DGPS. Through the research, we developed instrumentation to compare PAR track data with DGPS track data, which can be used in reducing the number of PAR verification Flight utilizing it as a system measuring PAR accuracy at PAR installation phase.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.107-116
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• 2022

Recently, research has been actively conducted on the technology of inspection facilities through image-based analysis assessment of human-inaccessible facilities. This research was conducted to study the conditions of deep learning-based imaging data on bridges and to develop an evaluation prototype program for bridges. To develop a deep learning-based bridge damage detection prototype, the Semantic Segmentation model, which enables damage detection and quantification among deep learning models, applied Mask-RCNN and constructed learning data 5,140 (including open-data) and labeling suitable for damage types. As a result of performance modeling verification, precision and reproduction rate analysis of concrete cracks, stripping/slapping, rebar exposure and paint stripping showed that the precision was 95.2 %, and the recall was 93.8 %. A 2^nd performance verification was performed on onsite data of crack concrete using damage rate of bridge members.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.69-76
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• 2005

The laser interferometer system such as HP5529A is one of the most powerful equipment fur measurement of the straightness error in precision stages. The straightness measurement system, HP5529A is composed of a Wollaston prism and a reflector. In this system, the straightness error is defined as relative lateral motion change between the prism and the reflector and computed from optical path difference of two polarized laser beams between these optics. However, rotating motion of the prism or the reflector used as a moving optic causes unwanted straightness error. In this paper, a compensation method is proposed for removing the unwanted straightness error generated by rotating the moving optic and an experiment is carried out for theoretical verification. The result shows that the unwanted straightness error becomes very large when the reflector is used as the moving optic and the distance between the reflector and the prism is far. Therefore, the prism must be generally used as the moving optic instead of the reflector so as to reduce the measurement error. Nevertheless, the measurement error must be compensated because it's not a negligible error if a rotating angle of the prism is large. In case the reflector must be used as the moving optic, which is unavoidable when the squareness error is measured between two axes, this compensation method can be applied and produces a better result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.800-803
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• 2004

The refractive index of the laser interferometer is compensated using the simultaneously measured variations of room temperature and humidity in the method. In order to investigate the limit of compensation, the stationary test against two fixed reflectors mounted on the zerodur plate is performed firstly. From the experiment, it is confirmed that the measuring error of the laser interferometer can be improved from 0.12$\mu$m to 0.17$\mu$m by the application of the method. Secondly, for the verification of the compensating effect, it is applied to estimate the positioning accuracy of an ultra precision aerostatic stage. Two times of the refractive index compensation are performed to acquire the positioning error of the stage from the initially measured data, that is, to the initially measured positioning error and to the measured positioning error profile after the NC compensation. Although the positioning error of anaerostatic stage cannot be clarified perfectly, it is known that by the compensation method, the measuring error by the laser interferometer can be improved to within 0.15$\mu$m. English here.