• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.28-34
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• 2003

In the present study, three-dimensional finite element analysis was performed to investigate the effects of internal wall thinning defect on the failure pressure of elbow in the piping system and to develop the failure pressure evaluation model. From the results of finite element analysis, the failure pressure was derived by employing local stress criteria, and the effects of thinning location, bend radius, and defect geometry on the failure pressure of internally wall thinned elbow were investigated. Also, based on these investigations and previous model developed to estimate the failure pressure of elbow with an external pitting defect, the failure pressure evaluation model to be applicable to the elbow containing an internal thinning defect was proposed and compared with the results of finite element analysis. The failure pressure calculated by the model agreed well with the results of finite element analysis.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.295-299
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• 2012

Defect generation during organic bottom anti-reflective coating (BARC) in the photo lithography process is closely related to humidity control in the BARC coating unit. Defects are related to the water component due to the humidity and act as a blocking material for the etching process, resulting in an extreme pattern bridging in the subsequent BARC etching process of the poly etch step. In this paper, the lower limit for the humidity that should be stringently controlled for to prevent defect generation during BARC coating is proposed. Various images of defects are inspected using various inspection tools utilizing optical and electron beams. The mechanism for defect generation only in the specific BARC coating step is analyzed and explained. The BARC defect-induced gate pattern bridging mechanism in the lithography process is also well explained in this paper.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.702-704
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• 2003

In this paper, analysis of bobbin probe signal in steam generator tube with bulge defect on CE system 80 nuclear power plant is represented. The CE system 80 steam generator is adopted in ULJIN-4 nuclear power plant. From Maxwell's equation, the electromagnetic governing equation for eddy current problem is derived and by performing the finite element formulation the 3-dimensional finite element code with brick element is developed. For the ease of the comparison the numerical results with experimental ones, the calculated signals are adjusted by using the ASME standard 100[%] through hole signal. For analysis of the effect of variation of the bulge depth on the impedance signal 0.2[mm] and 0.4[mm] depth of bulge defect signals are calculated and analyzed. As the depth of the bulge defect is increased, the magnitude of the signal is increased, too. But the rate of the increment of the signal is less than that of the depth of defect. From the result of this paper, we can obtained the information of the effect of bulge defect on the impedance signal.

• KIEAE Journal
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• v.7 no.6
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• pp.127-132
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• 2007

Recently, the cases of lawsuit are growing on residential defects. Though, mostly residential construction companies are trying to mitigate resident's dissatisfaction due to keep the company's brand image by operating customer service team, some representatives of apartment buildings initiate litigations without any negotiation with countrepartner companys incited by planned suit lawyers. But lawsuit takes longtime to sentence(about more than one year), and judged amount of money are very few (averaging about 14%) compared with asserted amount of it. To suggest the improving alternatives, the types and problems of defect lawsuit on apartment complex are analyzed.

• Journal of Chest Surgery
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• v.16 no.3
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• pp.310-315
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• 1983

The combined anomaly of pulmonary stenosis with atrial or ventricular septal defects is usually associated with decreased pulmonary blood flow and right to left shunt, and result in generalized cyanosis. Non-cyanotic pulmonary stenosis patients have generally been considered to have isolated pulmonary stenosis with intact septa. We are going to report a case of pulmonary stenosis with septal defects who have no frank cyanosis at rest because of the predominant intracardiac shunt from left to right. Recently, we managed surgically a case of pulmonary valvular stenosis combined with secundum type atrial septal defect, type II ventricular septal defect, and patent ductus arteriosus. The clinical manifestations of this patient were exertional dyspnea, frequent upper respiratory infection, chest discomfortness and lethargy since late childhood and these had been progressively aggravated. Pulmonary valvular stenosis, atrial septal defect and ventricular septal defect were closed through simply right atriotomy and patent ductus arteriosus through pulmonary arteriotomy. Immediate postoperative course was uneventful and one year follow up is excellent.

• Journal of Veterinary Clinics
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• v.35 no.6
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• pp.286-289
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• 2018

A 4-year-old castrated male Maltese was referred to our hospital with heart murmur. The client did not recognize any symptoms. Auscultation revealed systolic murmur located at the left heart base. Radiographs showed right-sided cardiomegaly with the main pulmonary artery bulging and enlargement of pulmonary vessels. Echocardiogram revealed a small ventricular septal defect and a large atrial septal defect. There was also a common atrioventricular valve. Based on diagnostic imaging studies, the dog was diagnosed with transitional atrioventricular septal defect.

• Smart Structures and Systems
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• v.23 no.1
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• pp.71-79
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• 2019

In general, it may be advantageous to measure the pressure pulsation near a valve to detect a valve defect in a linear compressor. However, the acceleration signals are more advantageous for rapid classification in a mass-production line. This paper deals with the performance improvement of fault classification using only the compressor-shell acceleration signal based on the relation between the refrigerant pressure pulsation and the shell acceleration of the compressor. A transfer function was estimated experimentally to take into account the signal noise ratio between the pressure pulsation of the refrigerant in the suction pipe and the shell acceleration. The shell acceleration signal of the compressor was modified using this transfer function to improve the defect classification performance. The defect classification of the modified signal was evaluated in the acceleration signal in the frequency domain using Fisher's discriminant ratio (FDR). The defect classification method was validated by experimental data. By using the method presented, the classification of valve defects can be performed rapidly and efficiently during mass production.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.215-223
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• 2021

The domestic CANDU nuclear power plants have been operated for a long time and various unforeseen spent fuel defects have been discovered. As the spent fuel defects are important factors in the safety of the nuclear power plant, a study on the analysis of the spent fuel defects to prevent their recurrence is necessary. However, in cases where the fuel rods inside the fuel assembly are defected, it is difficult to dismantle the fuel assembly owing to their welded structure and the facility conditions of the plant. Therefore, it is impossible to analyze the spent fuel defect because it is difficult to visually check the shape of the fuel defect. To resolve these problems, an analysis technology that can predict the number of defected fuel rods and defect size was developed. In this study, we developed a methodology for investigating the root cause of spent fuel defects using a database of the earlier fuel defects in the plants. It is anticipated that in the future this analysis technology will be applied when spent fuel defects occur.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.64-69
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• 2021

In this paper, a method for improving the defect classification performance in low contrast, ununiformity and featureless steel plate surfaces has been studied based on deep convolution neural network and transfer-learning neural network. The steel plate surface images have low contrast, ununiformity, and featureless, so that the contrast between defect and defect-free regions are not discriminated. These characteristics make it difficult to extract the feature of the surface defect image. A classifier based on a deep convolution neural network is constructed to extract features automatically for effective classification of images with these characteristics. As results of the experiment, AlexNet-based transfer-learning classifier showed excellent classification performance of 99.43% with less than 160 seconds of training time. The proposed classification system showed excellent classification performance for low contrast, ununiformity, and featureless surface images.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.149-154
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• 2022

In recent years, the application of deep learning method to computer vision has shown to achieve great performances. Thus, many research projects have also applied deep learning technology to railroad defect detection. In this paper, we have reviewed the researches that applied computer vision based deep learning method to railroad defect detection and inspection, and have discussed the current trend and the direction of those researches. Many research projects were targeted to operate automatically without visual inspection of human and to work in real-time. Therefore, methods to speed up the computation were also investigated. The reduction of the number of learning parameters was considered important to improve computation efficiency. In addition to computation speed issue, the problem of annotation was also discussed in some research projects. To alleviate the problem of time consuming annotation, some kinds of automatic segmentation of the railroad defect or self-supervised methods have been suggested.