• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.1
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• pp.37-42
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• 2010

The stay cylinder weld at the steam generator of Korean Standard Nuclear Power Plants is safety class I component and is subjected to be inspected by the volumetric examination such as ultrasonic method. As accessibility of this area is limited due to the narrow space and high radiation, the existing manual inspection method involves various difficulties. Moreover operators may be exposed to internal contamination by contaminated dust during the surface buffing process to improve the inspection reliability of this area. Recently the new automatic inspection system for stay cylinder welds has been developed. The inspection system basically consists of a driving assembly, data acquisition device and signal processing units. The driving assembly is classified by 1) the scanner for inspecting and buffing the weld, 2) pillars for guiding the scanner and 3) the base frame for loading and supporting pillars. The scanner has 4 sensor modules to inspect in 4 refracted angles and 4 incident directions. These components can be inserted into the skirt of the stay cylinder through the manway hole and assembled easily by one-touch in the skirt. Data acquisition device and signal processing units developed in previous works are also newly upgraded for better processing of data analysis and evaluation. The system has been successfully demonstrated not only in the mock-up but also in the field. In this paper, newly developed inspection system for the stay cylinder weld of the steam generator is introduced and their field applications are discussed.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.45-53
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• 2017

PURPOSES: The objectives of this study are to develop a new cold-applied crack sealant and to evaluate its properties and field applicability by comparing with other conventionally used crack sealants. METHODS : A new cold-applied crack sealant was developed by using neoprene latex to improve material properties. The fundamental properties such as viscosity, residue %, penetration, and softening point of the developed crack sealant were tested by TxDOT criteria to evaluate crack sealing capability. Moreover, the performance of the developed cold-applied crack sealant was evaluated under both laboratory and field conditions. In the laboratory, the bond property was evaluated using the developed cold-applied crack sealant and conventional hot-applied crack sealant by the bond-properties test standardized under ASTM D 6690. In the field, test sections were constructed on three areas: a trunk road, bus-only lane, and motorway, with the developed crack sealant and three conventional crack sealants. After construction, early field-inspection was performed on the test sections. RESULTS AND CONCLUSIONS : Overall, the developed cold-applied crack sealant demonstrates reasonable storage stability, durability, and bond property compared to conventional hot-applied crack sealants. From the test sections, it was established that the developed cold-applied crack sealant does not pose construction issues. Moreover, the early performance was verified through field inspection. However, as the field inspection was conducted a week after the construction, it is necessary to conduct an inspection of performance from a long-term point of view.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.117-121
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• 2002

The purpose of this study was to Identification the Risk of construction method to protect and reduce the risk of construction period. For this study we are using the pre and during construction period Inspection list. The inspection list was used by construction company for check a flaw of Construction field. So we rearrange the individual item of inspection list to match the Risk factor. This inspection list usually has the difference of importance because this list is not made by Method which is not focused on Method. Therefore, To find the difference of these importance, We surveyed this matter by doing interview of specialist group. To find the application of field and the possibility of measurement of Risk status, We tested Risk occurring frequency and it's strength by checking the level of Risk. The results of this study were as follows; Each Method Check List made out through the rearrangement of Construction Inspection list which used in construction company. To solve and compensate the matter which happened by changing the each Method Check List to each General Inspection List, we added the each Method Check List by checking the importance of check list of each process. By doing this, The Check List for finding Risk level of Method was created by using the check list of each Method.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.668-670
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• 1999

We have developed a automatic surface inspection system for cold Rolled strips in steel making process for several years. We have experienced the various kinds of surface inspection systems, including linear CCD camera type and the laser type inspection system which was installed in cold rolled strips production lines. But, we did not satisfied with these inspection systems owing to insufficient detection and classification rate, real time processing performance and limited line speed of real production lines. In order to increase detection and computing power, we have used the Dark Field illumination with Infra_Red LED, Bright Field illumination with Xenon Lamp, Parallel Computing Processor with Area typed CCD camera and full software based image processing technique for the ease up_grading and maintenance. In this paper, we introduced the automatic inspection system and real time image processing technique using the Object Detection, Defect Detection, Classification algorithms. As a result of experiment, under the situation of the high speed processed line(max 1000 meter per minute) defect detection is above 90% for all occurred defects in real line, defect name classification rate is about 80% for most frequently occurred 8 defect, and defect grade classification rate is 84% for name classified defect.

• Fire Science and Engineering
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• v.22 no.4
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• pp.50-53
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• 2008

This study has been conducted for the purpose of considering the problems expected when checking the smoke detector at site and how to improve the smoke detector. We have conducted this study focused on checking the problems expected upon site inspection and finding out the way of improving the site inspection by analyzing the reliability and performance of instrument used upon site inspection. The test results show that some problems exist in the reliability and performance of instrument used for the site inspection of smoke detector way of inspecting the inspection instrument.

• Journal of the Korea Institute of Building Construction
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• v.2 no.4
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• pp.131-135
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• 2002

The purpose of this study was to Identification the Risk of construction method to protect and reduce the risk of construction period. For this study we are using the pre and during construction period Inspection list. The inspection list was used by construction company for check a flaw of Construction field. So we rearrange the individual item of inspection list to match the Risk factor. This inspection list usually has the difference of importance because this list is not made by Method which is not focused on Method. Therefore, To find the difference of these importance, We surveyed this matter by doing interview of specialist group. To find the application of field and the possibility of measurement of Risk status, We tested Risk occurring frequency and it's strength by checking the level of Risk. The results of this study were as follows; Each Method Check List made out through the rearrangement of Construction Inspection list which used in construction company. To solve and compensate the matter which happened by changing the each Method Check List to each General Inspection List, we added the each Method Check List by checking the importance of check list of each process. By doing this, The Check List for finding Risk level of Method was created by using the check list of each Method.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.11
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• pp.76-83
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• 2007

The dark-field laser scattering system has been developed to inspect surface defects in infrared cut-off filters and then laser scattering characteristics against the defects are investigated. The qualitative analysis for the reliable and accurate detection performance is described through the correlation between incident angles of a laser and viewing ones of a camera. In this paper, reliable and important information with laser scattering is given for the surface defect inspection of IR filters. Its performance has been verified through various experiments.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1442-1447
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• 2003

Computer is a very powerful machine which is widely using for data processing, DB construction, peripheral device control, image processing etc. Consequently, many researches and developments have progressed for high performance processing unit, and other devices. Especially, the core units such as semiconductor parts are rapidly growing so that high-integration, high-performance, microminiat turization is possible. The packaging in the semiconductor industry is very important technique to de determine the performance of the system that the semiconductor is used. In this paper, the inspection of the inner defects such as delamination, void, crack, etc. in the semiconductor packages is studied. ESPI which is a non-contact, non-destructive, and full-field inspection method is used for the inner defect inspection and its results are compared with that of C-Scan method.

• Journal of the Korean Society for Railway
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• v.5 no.2
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• pp.104-111
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• 2002

The purpose of interlocking system was to prevent the route for a train being set up and its protecting signal cleared if there was already another, conflicting route set up and the protecting signal for that route cleared. This paper proposed Interlocking Inspection System(IIS) consisting of interlocking simulator and field simulator to operate interlocking test of computer based Electronic Interlocking System(EIS) in this paper. Interlocking simulator consists of Design Edit System(DES), Logical Database Management Tool(LDMT) and real-time confirming system, field simulator is a equipment to simulate a control object of EIS and constitutes configuration operated in 19 inch standard rack. As a result of test to prove capacity of this IIS, the efficiency was shown as excellent. Therefore by using inspection system, we obtain every advantages. It has the functions for test data generation and automatic test execution based on personal computer. Time and cost for test work can be reduced more efficiently by using this developed inspection system

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.2
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• pp.151-161
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• 1998

In this study, an attempt is made to apply the concept of fuzzy-bayesian theory to the integrity assessment of RC highway bridge, and uncertainty states are represented in terms of fuzzy sets which define several linguistic variables such as "very good", "good", "average", "poor", "very poor", etc. Especially, the concept of fuzzy conditional probability aids to derive a new reliability analysis which includes the subjective assessment of engineers without introducing any additional correction factors. The fuzzy concept are also used as reliability indexes for the condition assessment based on the proposed models, the proposed fuzzy theory-based approach with the results of visual inspection and extensive field load tests are applied to the integrity assessment of a new RC highway bridge, namely, Jichok bridge.