• Proceedings of the KSME Conference
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• 2001.06a
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• pp.529-533
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• 2001

NDI technique system using AC current is newly developed for inspection of defects. This technique is non-contact measurement system and can be applied for locating and sizing of surface defects in components. In this paper, the technique was applied for evaluating the location and size for 2-dimensional surface cracks and we had investigated the influence of frequency and lift-off. The results show that defects are able to detect with the variety of voltage, and the measuring voltage for the depth of defects are under the influence of the measuring frequency and the lift-off.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.153-157
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• 2008

The construction market has gradually become complexity, variety and specialization, and then owner's requirements about quality has become various. In order to solve the problem such as stated above, advanced constructions in United Kingdom, Japan and United States have introduced warranty contract which is warranted to quality and performance for need of owner in determined term to ensure the quality of construction since 1960s. However, the interior of a country encounter another problem result from defects liability what indefiniteness of defects standard, excess responsibility period, social recognition of be identical fraudulent work and defects, and contract with ascendancy of owners. etc, so builders concerned more excess defects liability than the quality of construction. The purpose of this study is to analysis of warranty contract in order to solve the problem such as stated above.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.81-85
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• 2001

The color vision was composed of the wavelength absorption of three R. G. B cone photo-receptors and the r-g, y-b channel of an opponent process. The color vision defects mechanism for the electric circuit made up a photo cell, relay switch and transformer. This mechanism very well applied to the color vision defects mechanism owing to be y-b chromatic valence function in case of a cone R or G defects and to be r-g chromatic valence function in case of a cone B defects.

• Transactions of Materials Processing
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• v.18 no.5
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• pp.422-427
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• 2009

Computed tomography(CT) has been applied to measure micro-defects in the aluminum knuckle parts manufactured by the thixoforming process. 6061 aluminum alloys were used to form knuckle samples in the semi-solid temperature after the SIMA processing of billets. Tensile specimens were cut from the different locations in a thixoformed knuckle. The size and the distribution of forming defects in tensile specimens were analyzed using CT scanning and image analysis technology before tensile tests. It has been qualitatively shown that the stress-strain curves were significantly affected by the size and the distribution of forming defects although the defect sizes lie in the range of micro-meters.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.990-995
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• 1989

Since 1984, 24 patients underwent repair of atrioventricular septal defect. Nineteen had a partial defect and 5 had a complete atrioventricular septal defect. There were 9 men and 15 women, ranging in age from 1 to 50 years [mean age, 13.3 years]. Four patients had a Downs syndrome. Additional congenital heart defects were present in 11 patients. One patient had palliative operation prior to total correction. In partial defects, the primum atrial septal defect was closed with Xenomedica patch and the mitral valve was repaired with simple closure of the septal commissure. Central incompetence from annular dilatation was repaired by a local annuloplasty. In complete defect, the septal defects were closed with two patches except one. Operative mortality was 5% in partial defects and 60% in complete defects and low cardiac output was the commonest etiology. In a mean follow-up period of 27.9 months [range, 4 to 63 months] there were no late death and no instances of late-onset complete heart block. One patient required reoperation [MVR] for residual mitral regurgitation. The majority of patients were asymptomatic and mean postop. NYHA functional class was 1.2.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.75-81
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• 2015

Modeling and analysis using a ray tracing method for internal defects were described. Reflection and refraction of rays on the interface of defects were modeled using the Harvey model and the Lambertian model. The diffraction on the interface of defects affected the incoming signals and it could evaluate any defects in the matter and its signal would be analyzed with the ray tracing simulation. The simulation results were compared with actual detecting signals and the ray tracing model was shown in good agreement with experimental data. This method has a possibility to be used as wave propagation modeling in non-destructive testing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.89-92
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• 2007

Since 1960s, advanced constructions have introduced warranty contract which is warranted to quality and performance for need of owner in determined term to ensure the quality of construction. However, the interior of a country encounter another problem result from Defects Liability what indefiniteness of defects standard, excess responsibility period, social recognition of be identical fraudulent work and defects, and contract with ascendancy of owners. etc, so builders concerned more excess defects liability than the quality of construction. The purpose of this study is to analysis of warranty contract in order to solve the problem such as stated above.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1930-1932
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• 2000

PD in defects of solid insulation system is very harmful since it leads to deteriorate insulation system by. the discharge electrons and ions bombarding the insulation surface and the action of chemical products that are formed by discharges. PD is used to detect and recognize defects and degradation of insulation system However, there are still marked difficulties to recognize defects by PD methode. In this paper, we investigated properties of PD of defects in solid insulation by using statical methods and classified PD patterns of surface discharge, electrical tree and void discharge with source of discharge, we used specific distributions such as $H_n(q)$, $H_{an}(\phi)$, $H_n(\phi)$, $H_a(\phi)$ to recognize defects of solid insulation system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.222-228
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• 1999

The two-microphone sound-intensity technique has been used for the detection of defects in radially loaded ball bearings. The difference in the sound-intensity levels measured for bearings with no defect and for those with intentionally introduced defects of different sizes in their elements under various operating conditions of loads and speeds is demonstrated. A change in the intensity frequency spectrum because of the defects is observed. The results show that the detectability of an outer-race defect is much better than that of on inner-race or ball defect. It is difficult to detect defects at lower speeds. Sound-pressure measurements were also performed fur comparison, and it is shown that the detectability of defects by sound-intensity measurements is better than that by sound-pressure measurements.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.6 s.261
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• pp.651-658
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• 2007

A new tree-structured neural network classifier is proposed for the automatic real-time inspection of cold-rolled steel strip surface defects. The defects are classified into 3 groups such as area type, disk type, area & line type in the first stage of the tree-structured neural network. The defects are classified in more detail into 11 major defect types which are considered as serious defects in the second stage of neural network. The tree-structured neural network classifier consists of 4 different neural networks and optimum features are selected for each neural network classifier by using SFFS algorithm and correlation test. The developed classifier demonstrates very plausible result which is compatible with commercial products having high world-wide market shares.