• Composites Research
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• v.35 no.1
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• pp.8-12
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• 2022

Analysis of defect signals inside glass fiber reinforced polymer (GFRP) was conducted through deconvolution of terahertz (THz) wave. The GFRP specimen with internal defects was manufactured and the THz signal was measured through the reflection mode of the Terahertz Time-Domain Spectroscopy (THz-TDS) system. For deconvolution of the measured THz signal, the peak position of the THz signal was amplified through Normalized Cross Correlation (NCC) of the incident and detected THz signals. The position and intensity of the amplified peak were extracted as impulse, and the extracted signal of the impulse position was removed from the THz original signal. By repeating the process, the critical impulses, which represent boundary of the specimen, were derived. The deconvolution process was verified by confirming that the original THz signal without noise can be restored through the convolution of the critical impulses and the incident signal. From the derived critical impulses, the thickness of the internal defect in the GFRP was calculated through the detection time of impulses within 15 ㎛ accuracy.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.1-12
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• 2023

To make semiconductor chips, a number of complex semiconductor manufacturing processes are required. Semiconductor chips that have undergone complex processes are subjected to EDS(Electrical Die Sorting) tests to check product quality, and a wafer bin map reflecting the information about the normal and defective chips is created. Defective chips found in the wafer bin map form various patterns, which are called defective patterns, and the defective patterns are a very important clue in determining the cause of defects in the process and design of semiconductors. Therefore, it is desired to automatically and quickly detect defective patterns in the field, and various methods have been proposed to detect defective patterns. Existing methods have considered simple, complex, and new defect patterns, but they had the disadvantage of being unable to provide field engineers the evidence of classification results through deep learning. It is necessary to supplement this and provide detailed information on the size, location, and patterns of the defects. In this paper, we propose an anomaly detection framework that can be explained through FCDD(Fully Convolutional Data Description) trained only with normal data to provide field engineers with details such as detection results of abnormal defect patterns, defect size, and location of defect patterns on wafer bin map. The results are analyzed using open dataset, providing prominent results of the proposed anomaly detection framework.

• Journal of the Korean Society of Safety
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• v.38 no.6
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• pp.1-8
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• 2023

The health state of the oil transformer is evaluated by the age of use and the state of internal defects. Mineral Oil, used as an insulator for oil transformers, creates specific gases and compounds through chemical reactions caused by heat, moisture, and partial discharge inside the transformer. It is possible to determine the aging and defect of the transformer through these gases and compounds. So, it is an important indicator to evaluate the health of a transformer. In this study, factors for assessing the health of transformers were hierarchically categorized, and key factors for each hierarchy were selected for design weighting. These weights were determined through surveys conducted with experts in the fields of transformer design, operation, and quality. For the health of a transformer, defect-related factors are approximately three times more important than factors related to aging. Additionally, defect-related factors showed a higher weighting for gases generated at high temperatures. Furthermore, Furan was determined to have a high weight, directly associated with insulating paper aging. Based on these findings, a health index was proposed, and a comparative analysis was conducted by categorizing 40 operational transformers into normal and comparison groups to evaluate and validate it.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.11
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• pp.23-29
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• 2010

This paper presents a method for constructing a memory system using defective memory chips comprising faulty storage blocks. The three-dimensional memory system introduced here employs a die-stacked structure of faulty memory chips. Signals lines passing through the through-silicon-vias (TSVs) connect chips in the defect tolerant structure. Defective chips are classified into several groups each group comprising defective chips having faulty blocks at the same location. A defect tolerant memory system is constructed using chips from different groups. Defect-free storage blocks from spare chips replace faulty blocks using additional routing circuitry. The number of spare chips for defect tolerance is $s={\ulcorner}(k{\times}n)/(m-k){\urcorner}$ to make a system defect tolerant for (n+s) chips with k faulty blocks among m independently addressable blocks.

• Journal of the Korean Professional Engineers Association
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• v.33 no.5
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• pp.59-64
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• 2000

This improvement case to be introduced of all welders, welding operator, tack welders and welding inspector for reducing of welding defect rate and good quality.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.125-130
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• 2021

Scaffold is used to produce bio sensor. Scaffold is required high dimensional accuracy. 3D printer is used to manufacture scaffold. 3D printer can't detect defect during printing. Defect detection is very important in scaffold printing. Real-time defect detection is very necessary on industry. In this paper, we proposed the method for real-time scaffold defect detection. Real-time defect detection model is produced using CNN(Convolution Neural Network) algorithm. Performance of the proposed model has been verified through evaluation. Real-time defect detection system are manufactured on hardware. Experiments were conducted to detect scaffold defects in real-time. As result of verification, the defect detection system detected scaffold defect well in real-time.

• Journal of Chest Surgery
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• v.19 no.4
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• pp.678-682
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• 1986

A case of ventricular septal defect associated with aorticopulmonary septal defect, left superior vena cava, and pulmonary hypertension in 6 years old boy is presented. Teflon patch closure of ventricular septal defect through transtricuspital procedure and division and suture closure of aorticopulmonary window performed under cardiopulmonary bypass with cardioplegia. The postoperative course was uneventful and discharged with good general condition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.210-213
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• 1995

In this study,the effect of both process parameters (wheel velocity, friction coefficients between die and billet, etc) and die-shape (abutment height and shape, flash gap, etc.) on the surface defect on forming process is theoretically investigated. For this work, computer simulation was performed by using the DEFORM, a commercial FEM code. Through numerous simulations with different parameters and die shapes, We propose one optimal die shape for CONFORM process which can remove surface defect.

• Journal of Chest Surgery
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• v.12 no.2
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• pp.113-118
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• 1979

The muscular variety of congenital ventricular septal defect [Type IV VSD] comprises from 2 to 18% of the total number of patients and has multiple defects. It is difficult to diagnose by usual angiographic study. Out of 116 cases of isolated ventricular septal defects repaired at this hospital in 20 years period from 1959 and to May 8, 1979, 2 cases had muscular defect which was treated through vertical right ventriculotomy without any problems. Single defect was found in both cases and in one case PDA was associated with Type IV VSD.

• Archives of Reconstructive Microsurgery
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• v.16 no.2
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• pp.119-124
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• 2007

Purpose: We reconstructed the skin defect of lower legs exposing muscles, tendons and bone with fasciocutaneous sural artery flap and report our cases. Materials and Methods: Between March 2005 and September 2006, 8 cases of skin defect were reconstructed with fasciocutaneous sural artery flap. Defect site were 4 case of ankle and foot and 4 cases of lower leg. The average defect size was $4{\times}4\;cm^2$. There were 5 men and 3 women and mean age was 52.2 years. We evaluated the viability of flap, postoperative complication, healing time, patient's satisfaction. Results: There was no flap failure in 8 cases. But recurrent discharge in 2 cases was healed through several times adequate debridement and delayed suture without complication. Flap edema may be due to venous congestion was healed through leg elevation and use of low molecular weight heparin. Mean time to heal the skin defect was 4 weeks. No infection and recurrence in follow up period. Cosmetic results as judged by patients were that 5 cases are good and 3 cases are fair. Conclusion: Sural artery flap is good treatment method among the numerous methods in the cases of skin defect, with soft tissue exposed, which is not covered with debridment and skin graft. Sural artery flap is useful method for the skin defect of lower legs because it is simple procedure, has constant blood supply and relatively good cosmetic effect.