• KIEE International Transactions on Electrophysics and Applications
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• v.2C no.5
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• pp.239-245
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• 2002

In this work, in order to realize the possible defects at the cable joint interface, four different types of artificial defects are provided : conducting, insulating substances, void and scratches. The analysis related to the PD patterns has been performed by means of conventional Phase Resolved Partial Discharge Analysis (PRPDA) and Chaotic Analysis of Partial Discharge (CAPD) as well which was proposed by our previous communication. As a result, it could be pointed out that each defect has shown particular characteristics in its pattern respectively and that the nature of defect causing partial discharge could be identified more distinctively when the CAPD is combined with the conventional statistic method, PRPDA.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.5
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• pp.199-204
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• 2002

In order to recognize the deterioration of insulation system by partial discharge (PD), the characteristics of PD patterns which are occurring at the interface between epoxy and rubber materials in extra high voltage cable joints, have been investigated. The artificial defects such as voids, metal particles, insulation fiber and water impregnated insulation fiber are planted between the interfaces. A high frequency partial discharge detection system was used for measuring PD signals. An analysis of the PD patterns is focused on the shape of PD pattern, phase, width and time-dependence for each artificial defect. The PD Patterns in each defect show the different behaviors and it is suggested that the precise discrimination of PD patterns could be used for the diagnosis of deterioration in the insulation systems.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.231-232
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• 2023

It is important to utilize an efficient quality management platform because the management of deadlines at construction sites requires rapid and accurate processing of numerous defect data in a short time. In this study, 30 domestic patents for defect management and image analysis were analyzed to examine the development status of quality management platforms using mobile devices. As a result of the analysis, research on automatically detecting defects using artificial intelligence has been actively underway in recent years, and advanced IT technologies have been converging in various ways into linked services.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.2
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• pp.144-150
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• 1992

This paper describes an application of artificial neural network to diagnose the defects of rotating machiner. Induction motor was used to the object of defect diagnosis. For defect diagnosis, the frequency spectrum of vibration was utilized. Learning method of applied neural network was back propagation. Neural network has following advantage; Once it has been learned, inference time is very short and it can provide a reasonable conclusion regardless of insufficient input data. So, this defect diagnosis system can be used superiorly to rule based expert system as quality inspection of rotating machinery in the shop.

• Journal of Power System Engineering
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• v.14 no.3
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• pp.46-51
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• 2010

A torsional guided wave was applied to detect a defect in petrochemical pipes. Phase and group velocity dispersion curves for the longitudinal and torsional modes of the inspected pipe were presented for the theoretical analysis. It was found through mode shape analysis that there was mode conversion when torsional wave is incident at an asymmetric defect. An artificial notch was fabricated in the pipe and the detectability was examined from the distance 2m of the end of the pipe by using magnetostrictive sensors. The relativities between the amplitude of the reflected signal and the size of the defect was examined. It was shown that the T(0,1) mode could be used for the long range inspection for the petrochemical pipes.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.136-146
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• 2022

Some surface defects make the weak quality of steel materials. To limit these defects, we advocate a one-stage detector model RetinaNet among diverse detection algorithms in deep learning. There are several backbones in the RetinaNet model. We acknowledged two backbones, which are ResNet50 and VGG19. To validate our model, we compared and analyzed several traditional models, one-stage models like YOLO and SSD models and two-stage models like Faster-RCNN, EDDN, and Xception models, with simulations based on steel individual classes. We also performed the correlation of the time factor between one-stage and two-stage models. Comparative analysis shows that the proposed model achieves excellent results on the dataset of the Northeastern University surface defect detection dataset. We would like to work on different backbones to check the efficiency of the model for real world, increasing the datasets through augmentation and focus on improving our limitation.

• 대한치과보철학회:학술대회논문집
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• 2002.11a
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• pp.117-118
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• 2002

• Archives of Craniofacial Surgery
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• v.17 no.4
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• pp.233-236
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• 2016

Scalp defect management is complicated secondary to reduced laxity in the scalp and forehead area. For reconstruction of larger defects with exposed bone and loss of the periosteal layer, free flap reconstruction is one option for single-stage surgery, although the procedure is lengthy and includes the possibility of flap loss. We successfully performed a single-stage reconstruction of a large scalp defect using a combination of artificial dermis, split-thickness skin graft, and full-thickness skin graft following wide excision of a cutaneous angiosarcoma, and present our method as one option for the treatment of large oncologic surgical defects in patients who are poor candidates for free flap surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.3
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• pp.227-232
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• 2007

The radial forearm fasciocutaneous flap(RFFF) is a well-known flap for the reconstruction of oral and maxillofacial defects. It was first described by Yang et al. in 1981 and Soutar et al. developed it for the reconstruction of intraoral defect. RFFF provides a reliable, thin, and pliable soft tissue/skin paddle that is amenable to sensate reconstruction. It also has a long vascular pedicle that can be anastomosed to any vessel in either the ipsilateral or contralateral neck. However, split thickness skin graft(STSG) is most commonly used to cover the donor site, and a variety of donor site complications have been reported, including delayed healing, swelling of the hand, persistent wrist stiffness, reduced hand strength, and partial loss of the graft with exposure of the forearm flexor tendon. Various methods for donor site repair in addition to STSG have been developed and practiced to minimize both functional and esthetic morbidity, such as direct closure, V-Y closure, full thickness skin graft, tissue expansion, acellular dermal graft. We got a good result of using artificial dermis($Terudermis^{(R)}$) and secondary STSG for the repair of RFFF donor site defect esthetically and report with a review of literature.

• Journal of the Korean Mathematical Society
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• v.50 no.5
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• pp.1129-1163
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• 2013

Based on finite element discretization, two linearization approaches to the defect-correction method for the steady incompressible Navier-Stokes equations are discussed and investigated. By applying $m$ times of Newton and Picard iterations to solve an artificial viscosity stabilized nonlinear Navier-Stokes problem, respectively, and then correcting the solution by solving a linear problem, two linearized defect-correction algorithms are proposed and analyzed. Error estimates with respect to the mesh size $h$, the kinematic viscosity ${\nu}$, the stability factor ${\alpha}$ and the number of nonlinear iterations $m$ for the discrete solution are derived for the linearized one-step defect-correction algorithms. Efficient stopping criteria for the nonlinear iterations are derived. The influence of the linearizations on the accuracy of the approximate solutions are also investigated. Finally, numerical experiments on a problem with known analytical solution, the lid-driven cavity flow, and the flow over a backward-facing step are performed to verify the theoretical results and demonstrate the effectiveness of the proposed defect-correction algorithms.