• Structural Engineering and Mechanics
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• v.91 no.1
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• pp.39-47
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• 2024

Bridge deterioration shows the change of bridge condition during its operation, and predicting bridge deterioration is important for implementing predictive protection and planning future maintenance. However, in practical application, the raw inspection data of bridges are not continuous, which has a greater impact on the accuracy of the prediction results. Therefore, two kinds of bridge deterioration models are established in this paper: one is based on the traditional regression theory, combined with the distribution fitting theory to preprocess the data, which solves the problem of irregular distribution and incomplete quantity of raw data. Secondly, based on the theory of Long Short-Term Memory (LSTM) Recurrent Neural Network (RNN), the network is trained using the raw inspection data, which can realize the prediction of the future deterioration of bridges through the historical data. And the inspection data of 60 prestressed concrete box girder bridges in Xiamen, China are used as an example for validation and comparative analysis, and the results show that both deterioration models can predict the deterioration of prestressed concrete box girder bridges. The regression model shows that the bridge deteriorates gradually, while the LSTM-RNN model shows that the bridge keeps great condition during the first 5 years and degrades rapidly from 5 years to 15 years. Based on the current inspection database, the LSTM-RNN model performs better than the regression model because it has smaller prediction error. With the continuous improvement of the database, the results of this study can be extended to other bridge types or other degradation factors can be introduced to improve the accuracy and usefulness of the deterioration model.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.126-131
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• 2001

Materials property data are necessary to secure the reliability of failure prevention techniques such as inspection and remaining life assessment of civil infrastructure and industrial facilities. However, there is no properly collected data in Korea, and those foreign data are hard to use because of the scattering of the sources, the difference of standards, etc. In this paper, materials property database system which has been constructed at Korea Research Institute of Standards and Science is introduced. Constructed database contains 145,000 numeric data of materials property for 600 kinds of metals and can be retrieved on the internet. The database system provides graphical user interface-based information searching functions necessary for the life evaluation and safety analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.775-778
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• 2017

This research describes system implementation for automatic inspection on wind pressure sensor production based on reliability improvement. The reliability is minimized by the automatic inspection system on the wind pressure sensor against the manual system. The system consists of the control system and monitoring system to be scanning the inspection processing. The inspection system for reliability is evaluated in Gage Repeatability and Reproducibility. The experimental results are improved about 2 times speed, measured error ${\pm}0.02V$, effectiveness 15%, missing probability 17% and false alarm 12% respectively. The system will be also improved by database and the product barcodes for the total quality control system based on the effective reliability in the future.

• Smart Structures and Systems
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• v.25 no.6
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• pp.733-749
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• 2020

This study presents a computer vision-based approach for representing time evolution of structural damages leveraging a database of inspection images. Spatially incoherent but temporally sorted archival images captured by robotic cameras are exploited to represent the damage evolution over a long period of time. An access to a sequence of time-stamped inspection data recording the damage growth dynamics is premised to this end. Identification of a structural defect in the most recent inspection data set triggers an exhaustive search into the images collected during the previous inspections looking for correspondences based on spatial proximity. This is followed by a view synthesis from multiple candidate images resulting in a single reconstruction for each inspection round. Cracks on concrete surface are used as a case study to demonstrate the feasibility of this approach. Once the chronology is established, the damage severity is quantified at various levels of time scale documenting its progression through time. The proposed scheme enables the prediction of damage severity at a future point in time providing a scope for preemptive measures against imminent structural failure. On the whole, it is believed that the present study will immensely benefit the structural inspectors by introducing the time dimension into the autonomous condition assessment pipeline.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.512-525
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• 2010

A PDP(Plasma Display Panel) Frame is critical part of PDP and also produces couple hundred thousand every month. In the process of mass production, product inspection is very important process. Also to increase the reliance, inspection each part and every final product is asked quite often. Purpose of this paper is to use computer vision system to inspect the PDP parts which is Automated visual process inspection. This paper contains the system design for inspecting defects of hole, tab, stud, rivet of PDP Frame. The system also can inspect various kinds of PDP frames. Quick and accurate 100% inspection of all shapes can improve the manufacturing productivity. Inspection results can be stored in a database and analyzed to find the cause of defects. After applying the system to the industry, the result shows the possibility of fast and accuracy of the inspection.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.173-180
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• 2011

This paper aims to propose an image processing technique for measuring the static displacement of bridges from general inspection photograph; the color, shape, and spatial transformations of an arbitrary image stored in bridge management system database are used. This study is verified by using numerical analyses with experiments; the results demonstrate that the static displacement of bridges are measured by proposed technique. Moreover, this technique is able to obtain the static structural response of the bridge with changes in temperatures.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.10
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• pp.121-129
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• 1995

The objective of this research is to develop an effective inspection planning strategy for sculptured surfaces by using 3-dimensional Coordinate Measuring Machine (CMM). First, the CAD/CAM database is generated by using the Bezier surface patch mathod and variable cutter step size approach for design and machining of the workpiece model. Then, optimum measuring point locations are determained based on the mean curvature analysis to obtain more effective inspection results for the given sample numbers. An optimal probe sequence generation method is proposed by implementing the Traveling Salesperson (TSP) algorithm and new guide point selection methods are suggested based on the concepts of the variable distance between the first and second guide points. Finally, simulation study and experimental work show the effectiveness of the proposed strategy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1155-1160
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• 2017

This paper describes a system implementation for the automatic inspection on the ventilating electronic device based on the reliability improvement. To be enhancement, the inspection error is minimized by the automatic inspection system on the ventilating apparatuses against the manual inspecting system. The system consists of the control system, software structure and monitoring system to be scanning the inspection processing. The inspection system for reliability improvement is evaluated in Gage Repeatability and Reproducibility. The experimental results are improved about 2 times inspecting speed, measured error ${\pm}0.02V$, effectiveness of discriminating performance 15%, missing probability 17% and false alarm probability 12% respectively in comparing with the manual inspection based on the wind pressure sensor. The system will be also improved more by making database and product bar codes for the total quality control system to the effective reliability enhancement in the future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.263-269
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• 2012

Condition-based maintenance (CBM) has been used as a useful concept for optimizing maintenance plan and decreasing maintenance cost in several kinds of plant sites. This study introduced an example that developed an integrated management system for maintenance parameters and hydraulic turbine of hydro-power plant in order to improve its maintenance system as applying CBM techinique. The integrated management system consists of three parts. One is a hardware part including PDA inspection system and several kind of precision measuring instruments. Another is a vibration monitoring system on hydraulic turbine. The other is a software part that takes charge of making hierarchy tree of maintenance parameters and their inspection route, managing accumulated database, assessing health condition of components, and supporting interface with other enterprise management system. The system has been installed at Chuncheon Hydro-power plant for test and demonstration. It is expected that the system can contribute database construction for diagnostics and prognostics on facility health condition and systematic accumulation of know-how on operation and maintenance of plant.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.212-218
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• 2000

The importance and role of pre-/in-service inspection(PSI/ISI) for nuclear power plant(NPP) components are intimately related to plant design, safety, reliability, operation, etc. In this paper, for an effective and efficient management of large amounts of PSI/ISI data in NPPs, an intelligent database program(WS-IDPIN) for PSI/ISI data management of NPP was developed. WS-IDPIN program enables the prompt extraction of previously conducted PSI/ISI conditions and results so that the time-consuming data management, painstaking data processing and analysis in the past are avoided. Furthermore, development of ISI UT auto flaw evaluation and acceptance module based on ASME Code Sec. XI were presented. This module can be used for any angle beam examination from flat plate to spherical shapes as selected by the proper azimuthal angle. This program can be further developed as a unique PSI/ISI data management expert system.