• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.1136-1142
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• 1999

A difficulty of the visual inspection for translated, magnified and rotated objects exists owing to the limitation of recognition rate. In this paper, we perform to define Integral Logarithm Transform(ILT), to consider its characteristic for implementation of Translation-, Magnification- and Rotation-invariant inspection system, and to compare with other methods in inspection error rate. By using magnification and rotation invariance properties of ILT, it makes easier than other methods to extract the rotation degree. The new method employs the ILT for the good/bad inspection of translated, magnified and rotated objects and experiment is performed to achieve translation, magnification and rotation invariance. In other methods both magnification and rotation invariance can't be available. As the result of he experiment, it is not better than the self-organizing map in the improvement of recognition rate, but it shows us the possibility to be used as a tool for the good/bad inspection system.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.372-378
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• 2013

In this paper, we research the localization problem of the crawler-type inspection robot for underwater structure which travels an outer wall of underwater structure. Since various factors of the underwater environment affect an encoder odometer, it is hard to localize robot itself using only on-board sensors. So in this research we used a depth sensor and an IMU to compensate odometer which has extreme error in the underwater environment through using Extended Kalman Filter(EKF) which is normally used in mobile robotics. To acquire valid measurements, we implemented precision sensor modeling after assuming specific situation that robot travels underwater structure. The depth sensor acquires a vertical position of robot and compensates one of the robot pose, and IMU is used to compensate a bearing. But horizontal position of robot can't be compensated by using only on-board sensors. So we proposed a localization algorithm which makes horizontal direction error bounded by using kinematics relationship. Also we implemented computer simulations and experiments in underwater environment to verify the algorithm performance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.4
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• pp.129-137
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• 2007

An algorithm is proposed for estimating axle loads of trucks moving over a bridge by measuring dynamic responses. The bridge was modeled by a beam structure in the current applications of the proposed algorithm. Among the state vectors, measured acceleration was used and displacement was computed from measured strain at the same location. Nodal force vectors were computed by using a ready-made database of equivalent nodal force transformation matrix. The algorithm was examined through simulation studies and laboratory experiments. The effects of measurement noise and velocity error were investigated through simulation studies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.4
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• pp.137-147
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• 1998

The neural net application was tried to develop the technique for monitoring the health status of a steel truss bridge which was scaled down to 1/15 of the real bridge for the laboratory experiments. The damage scenarios were chosen as 7 cases. The dynamic behavior, which was changed due to the breakage of the members, of the bridge was investigated by finite element analysis. The bridge consists of single spam, and eight (8) main structural subsystems. The loading vehicle, which weighs as 100 kgf, was operated by the servo-motor controller. The accelerometers were bonded on the surface of 7 cross-beams to measure the dynamic behavior induced by the abnormal structural condition. Artificial neural network technique was used to determine the severity of the damage. At first, the neural net was learnt by the results of finite element analysis, and also, the maximum detection error was 3.65 percents. Another neural net was also learnt, and verified by the experimental results, and in this case, the maximum detection error was 1.05 percents. In future study, neural net is necessary to be learnt and verified by various data from the real bridge.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.156-165
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• 2009

This study is to consider the character of cables in six World-Cup stadiums constructed in 2002 and to inspect problems on measurement natural frequencies interpretation and application of existing theory. The results of the experiment were shown that it was possible to determine the tension force of the real cables with an accuracy of 8% by taking the cable bending stiffness. But for the range of cable affected greatly by bending stiffness(${\xi}{\leq}7$), it was appeared the tendency to increase estimated error and was considered to need additional study of this range. Estimated tension error could not be improved so much in comparison to the case using single mode of vibration even through multiple modes of vibration were used.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.2
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• pp.153-158
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• 2021

In order to mitigate the vulnerability of the satellite navigation system against radio frequency interference, South Korea has been developing advanced terrestrial navigation system (eLoran) technology since 2016. The eLoran system synchronizes the transmission time of the pulse used in the existing Loran-C system with UTC and transmits correction information that can improve the position error. The eLoran system is known to reduce the position error of about 460 m of the existing Loran-C system to 20 m, and for this, the transmitter must be able to transmit eLoran signals according to more stringent standards. For this reason, an international standard that further developed the Loran-C signal standard established by US Coast Guard was established by Society of Automotive Engineers (SAE) International. In this paper, based on the analysis of the SAE9990 document, the international standard for eLoran transmission signals, a standard inspection process was produced to check whether the eLoran transmitter is transmitting signals in accordance with the standard.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.302-302
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• 2000

This paper presents the measurement and correction of PCB alignment errors for PCB-manufacturing machines. The conventional PCB-manufacturing machine doesn't have enough accuracy to accommodate the demand for high-resolution circuit pattern and high-density mounting capacity of electronic chips. It is because of alignment errors of PCB loaded to the PCB-manufacturing machine. Therefore, this study focuses on the development of the system which is able to measure and correct alignment errors whit high-accuracy. An automatic optical inspection part measures the PCB alignment error using two cameras, and the high-accuracy 3-axis stage makes correct of these error. The operating system is run in the environment of Window 98 (or NT). Finally we implemented this system to PCB screen printer and PCB exposure system.

• Korean Journal of Occupational Health Nursing
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• v.29 no.1
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• pp.78-87
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• 2020

Purpose: The purpose of this study was to identify the relationship between nursing error experience, coping behavior and job stress in operating room. Methods: A descriptive research design was used in this study. The participants were 228 operating room nurses in G city who surveyed between October 25 and November 25, 2017 using self-report questionnaires. The data were analyzed using IBM SPSS/WIN 24.0/AMOS WIN 24.0 Program, which determined frequency, percentage, mean, standard deviation, Pearson correlation coefficient, and structural equation model. Results: There were significant positive correlations between six sub-categories of nursing errors and job stress. We found negative correlations between coping behavior and job stress. There was a mediating effect of active coping between knowledge of nursing error and job stress. We found passive coping between inspection & monitoring related error and job stress. Conclusion: Study findings suggest that adequate education and the improvement in hospital environment and system should be required to reduce the nurses' job stress related to the patients' safety in operating room.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.132-140
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• 2019

In this study, a specimen composed of columns, walls, beams, and slabs was fabricated to investigate the estimated reliability using nondestructive test method for the location of structural members of reinforced concrete single layer structures. And for accurate analysis in the comparison process with the existing estimation formula, we try to analyze the reliability through statistical approach by using error rate comparison and Confidence interval estimation. As a result, The average error rate of the core test was 18.8% compared with the result of estimating the compressive strength using the ultrasonic pulse velocity method. The average error rate of the core test results compared with the result of estimating the compressive strength using the rebound hardness method was 20.1%, confirming the field applicability. it is judged that the reliability of the compressive strength estimation can be derived from the wall member to make a quick and efficient structure safety diagnosis using the ultrasonic pulse velocity method. In addition, it is judged that the reliability of the compressive strength estimation can be derived from the beam member to make a quick and efficient structure safety diagnosis using the rebound hardness method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.195-201
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• 2012

According to many customers' requests, optical measurement module (OMM) applications using automatic measuring devices to measure the machined part rapidly on a machine tool have increased steeply. Touch trigger probes are being used for job setup and feature inspection as automatic measuring devices, and this makes quality checking and machining compensation possible. Therefore, in this study, the use of touch trigger probes for accurate measurement of the machined part has been studied and a macro program for a hole measuring cycle has been developed. This hole is the most common feature to be measured, but conventional methods are still not free from measuring error. In addition, the eccentricity change of the least square circle was simulated according to the roundness error in a hole measurement. To evaluate the reliability of this study, the developed hole-measuring program was executed to measure the hole plate on the machine and verify the roundness error in the eccentricity simulation result.