• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3943-3948
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• 2022

Single-photon emission computed tomography is one of the reliable pin-by-pin verification techniques for spent-fuel assemblies. One of the challenges with this technique is to increase the total fuel assembly verification speed while maintaining high verification accuracy. The aim of the present study, therefore, was to develop an artificial intelligence (AI) algorithm-based tomographic image analysis technique for partial-defect verification of fuel assemblies. With the Monte Carlo (MC) simulation technique, a tomographic image dataset consisting of 511 fuel-rod patterns of a 3 × 3 fuel assembly was generated, and with these images, the VGG16, GoogLeNet, and ResNet models were trained. According to an evaluation of these models for different training dataset sizes, the ResNet model showed 100% pattern estimation accuracy. And, based on the different tomographic image qualities, all of the models showed almost 100% pattern estimation accuracy, even for low-quality images with unrecognizable fuel patterns. This study verified that an AI model can be effectively employed for accurate and fast partial-defect verification of fuel assemblies.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.122-126
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• 2002

A diagnostic test of 15.4kV cross-linked polyethylene(XLPE) ultra high voltage power cables from generator in the Soyanggang hydro electric power plant was conducted over 3 months, beginning April 2001. According to the results, in the case of the power cables from generator 1, there was little possibility of proceeding rapid1y to failure or defect because the data from diagnosis doesn't indicate any failure, deterioration or partial discharge. However, in the case of the power cables from generator 2, the. polarization index show a slight abnormal condition of the insulator that is not severe, and the deterioration was also identified as not severe. However, the partial discharge had an abnormal condition which was severe.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1915-1917
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• 2000

Laboratory experiments and on site measurements were conducted to detect partial discharges in GIS(Gas Insulated Switchgear) using the UHF(Ultra High Frequency) technique that has been applied many places in the world. Experimental results were in good agreement with calculation in locating a partial discharge source using mock-up GIS. Defect type and its location were inferred after a measurement on 345 kV GIS that showed some abnormal phenomenon. Precise examination inside the GIS coincided with the results inferred from the measurement. High reliability of UHF technique for site application was confirmed.

• 한국전기전자재료학회논문지
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• 제20권11호
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• pp.959-964
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• 2007

To investigate the influence of partial discharge(PD) distribution characteristics due to various defects on the power cable joints interface, we used the K-means clustering method. As the result of PD number(n) distribution analyzing on $\Phi-n$ graph, the phase angle($\Phi$) of cluster centroid shifted to $0^{\circ}\;and\;180^{\circ}$ increasing with applying voltage. It was confirmed that the PD quantify(q) and euclidean distance of centroid were increased with applying voltage from the centroid distribution analyzing of $\Phi-q$ plane. The dispersion degree was increased with calculated standard deviation of the $\Phi-q$ cluster centroid. The PD number and mean value on $\Phi-q$ graph were some different by electric field concentration with defect types.

• Journal of Chest Surgery
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• 제21권3호
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• pp.574-582
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• 1988

Endocardial cushion defects is a rare congenital heart disease. We experienced two complete endocardial cushion defects[ECD] and three partial ones, which were successfully repaired between 1986 and 1987. In a patient of complete ECD, associated with secundum ASD, Pulmonary stenosis and Down`s syndrome, the atrial and ventricular septal defects were closed separately with bovine pericardium and Dacron patches respectively, and then pulmonary stenosis was relieved by transannular patch widening in addition to valvotomy and infundibulectomy. In another patient with complete ECD, small interventricular communication was closed with simple suture with pledget and primum ASD was closed with pericardial patch. In first patient of partial ECD, primum atrial septal defect was closed with pericardial patch. In second patient of partial ECD, associated with secundum ASD, direct closure of secundum ASD and patch closure of primum ASD were performed. In third patient of partial ECD, associated with patent foramen ovale[PFO], primum ASD was closed with bovine pericardial patch and PFO was closed directly. In all patient except third patient of partial ECD, mitral clefts were closed with three or four 5-0 prolene interrupted sutures. Transient A-V dissociation developed postoperatively in two patients and transient nodal rhythm developed postoperatively in other two patients. Heart failure in complete ECD with Down`s syndrome was overcome with medical treatment.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1093-1101
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• 2015

Partial Discharge (PD) is a physical phenomenon, which causes defects and damages to the insulation. This phenomenon is regarded as the most important source of fault and defect in power transformers. Therefore, methods of high speed and precision are considered of special importance for the maintenance of transformers in localization of the origin of partial discharge. In this paper, the transformer winding is first modeled in a transient state by using RLC ladder network and multiconductor transmission line (MTL) models. The parameters of the two models were calculated by Ansoft Maxwell software, and the simulations were performed by Matlab software. Then, the PD pulses were applied to the models with different widths of pulses. With regard to the fact that the signals received after the application of PD had a variable frequency nature over time, and based on the wavelet transform and signal energy, a new method was presented for the localization of PD. Ultimately; the mentioned method was implemented on a 20 kV winding distribution transformer. Then, the performances of the models used in this paper, including RLC and MTL models, were compared in different frequency bands for the correct distinction of partial discharge location.

• 조명전기설비학회논문지
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• 제29권10호
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• pp.97-103
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• 2015

This paper presents the characteristics of partial discharge and radiated electromagnetic waves in the existence of a poor contact for the insulation diagnosis of eco-friendly power equipment. AC surface discharge experiment was conducted to simulate the poor contact between a hive voltage electrode (anode) and a solid insulator in $N_2/O_2$ mixture gas under a non-uniform field. The partial discharge voltage to be measured at 0.3MPa increased with the increase of the poor contact gap and was saturated with the gap. In addition to the partial discharge characteristics, it was verified that the defect of the poor contact can be diagnosed using the radiated electromagnetic waves due to the partial discharge, which measured by a biconical EMC antenna and a spectrum analyzer.

• Archives of Plastic Surgery
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• 제43권1호
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• pp.26-31
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• 2016

Background The global prevalence of myelomeningocele has been reported to be 0.8-1 per 1,000 live births. Early closure of the defect is considered to be the standard of care. Various surgical methods have been reported, such as primary skin closure, local skin flaps, musculocutaneous flaps, and skin grafts. The aim of this study was to describe the clinical characteristics of myelomeningocele defects and present the surgical outcomes of recent cases of myelomeningocele at our institution. Methods Patients who underwent surgical closure of myelomeningocele at our institution from January 2004 to December 2013 were included in this study. A retrospective chart review of their medical records was performed, and comorbidities, defect size, location, surgical procedures, complications, and the final results were analyzed. Results A total of 14 patients underwent surgical closure for myelomeningocele defects. Twelve cases were closed with direct skin repair, while two cases required local skin flaps to cover the skin defects. Three cases of infection occurred, requiring incision and either drainage or removal of allogenic materials. One case of partial flap necrosis occurred, requiring secondary revision using a rotational flap and a full-thickness skin graft. Despite these complications, all wounds eventually healed completely. Conclusions Most myelomeningocele defects can be managed by direct skin repair alone. In cases of large defects, in which direct repair is not possible, local flaps may be used to cover the defect. Complications such as wound dehiscence and partial flap necrosis occurred in this study; however, all such complications were successfully managed with simple ancillary procedures.

• Imaging Science in Dentistry
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• 제37권4호
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• pp.211-215
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• 2007

Purpose: The purpose of this study was to evaluate the effect of the kV on fractal dimension of trabecular bone in digital radiographs. Materials and Methods: 16 bone cores were obtained from patients who had taken partial resection of tibia due to accidents. Each bone core along with an aluminum step wedge was radiographed with an occlusal film at 0.08 sec and with the constant film-focus distance (32 cm). All radiographs were acquired at 60, 75, and 90 kV. A rectangular ROI was drawn at medial part, distal part, and the bone defect area of each bone core image according to each kV. The directional fractal dimension was measured using Fourier Transform spectrum, and the anisotropy was obtained using directional fractal dimension. The values were compared by the repeated measures ANOVA. Results : The fractal dimensions increased along with kV increase (p < 0.05). The anisotropy measurements did not show statistically significant difference according to kV change. The fractal dimensions of the bone defect areas of the bone cores have low values contrast to the non-defect areas of the bone cores. The anisotropy measurements of the bone defect areas were lower than those of the non-defect areas of the bone cores, but not statistically significant. Conclusion: Fractal analysis can notice a difference of a change of voltage of x-ray tube and bone defect or not. And anisotropy of a trabecular bone is coherent even with change of the voltage of x-ray tube or defecting off a part of bone.

• Archives of Reconstructive Microsurgery
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• 제20권2호
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• pp.89-95
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• 2011

Purpose: The purpose of this study was to evaluate the clinical results of anterolateral thigh free flap on soft tissue defect following wide excision in malignant soft tissue tumor of lower extremities. Methods: Between February 2005 to April 2010, we followed up 19 cases who were undergoing anterolateral thigh free flap because of soft tissue defect following wide excision of malignant soft tissue tumor in lower extremity, including 9 cases were heel, 5 cases in foot, 3 cases in ankle, 2 cases in knee and leg. We observed that of implanted area's color, peripheral circulation at 3, 5, 7 days after operation and evaluated operating time, amount of hemorrhage, implanted skin necrosis, additional operations, complications. And we also evaluated the oncologic results, including local recurrence, metastasis, and morbidity. Results: Average operation time of wide excision and anterolateral thigh free flap was 7 hour 28 minutes. 18(94.7%) of total 19 cases showed successful engraftment, on the other hand, failure of engraftment due to complete necrosis of flap in 1 case. In 18 cases with successful engraftment, reoperation was performed in 4 cases. Among them, removal of hematoma and engraftment of flap after bleeding control was performed in 3 cases, because of insufficient circulation due to the hematoma. In the remaining 1 case, graft necrosis due to flap infection was checked, and grafted after combination of wound debridement and conservative treatment such as antibiotics therapy, also skin graft was performed at debrided skin defect area. Skin color change was mainly due to congestion with hematoma, flap was not observed global congestion or necrosis except 4 cases which shows partial necrosis on margin that treated with conservative therapy. Conclusions: Anterolateral thigh free flap could be recommended for reconstruction of soft tissue defect following wide excision of malignant soft tissue tumor in lower extremity.