• 조명전기설비학회논문지
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• 제24권1호
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• pp.63-70
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• 2010

본 논문에서는 원자력발전소 증기세관 크기 예측을 위한 신경회로망 구조에 대해서 연구한다. 와류탐상 시험(ECT) 신호로부터 특징을 추출한 후, 결함크기 예측을 위해서 다층퍼셉트론 신경회로망을 이용한다. 결함크기 예측성능을 최대화하기 위해서는 신경회로망의 구조, 특히 은닉층 내의 뉴런의 개수를 신중히 결정하여야 한다. 본 논문에서는, 결함크기 예측을 위한 은닉층 내의 뉴런의 개수를 교차검증을 이용하여 매우 효과적으로 결정할 수 있음을 보인다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권2호
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• pp.97-107
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• 2019

Objectives: Small animal maxillofacial models, such as non-segmental critical size defects (CSDs) in the rabbit mandible, need to be standardized for use as preclinical models of bone regeneration to mimic clinical conditions such as maxillofacial trauma. The objective of this study is the establishment of a mechanically competent CSD model in the rabbit mandible to allow standardized evaluation of bone regeneration therapies. Materials and Methods: Three sizes of bony defect were generated in the mandibular body of rabbit hemi-mandibles: $12mm{\times}5mm$, $12mm{\times}8mm$, and $15mm{\times}10mm$. The hemi-mandibles were tested to failure in 3-point flexure. The $12mm{\times}5mm$ defect was then chosen for the defect size created in the mandibles of 26 rabbits with or without cautery of the defect margins and bone regeneration was assessed after 6 and 12 weeks. Regenerated bone density and volume were evaluated using radiography, micro-computed tomography, and histology. Results: Flexural strength of the $12mm{\times}5mm$ defect was similar to its contralateral; whereas the $12mm{\times}8mm$ and $15mm{\times}10mm$ groups carried significantly less load than their respective contralaterals (P<0.05). This demonstrated that the $12mm{\times}5mm$ defect did not significantly compromise mandibular mechanical integrity. Significantly less (P<0.05) bone was regenerated at 6 weeks in cauterized defect margins compared to controls without cautery. After 12 weeks, the bone volume of the group with cautery increased to that of the control without cautery after 6 weeks. Conclusion: An empty defect size of $12mm{\times}5mm$ in the rabbit mandibular model maintains sufficient mechanical stability to not require additional stabilization. However, this defect size allows for bone regeneration across the defect. Cautery of the defect only delays regeneration by 6 weeks suggesting that the performance of bone graft materials in mandibular defects of this size should be considered with caution.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.171-176
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• 2013

X-ray cross-sectional image-based inspection technique is one of the most useful methods to inspect the brazing joints of heat exchanger. Through X-ray cross-sectional image acquisition, image processing, and defect inspection, the defects of brazing joints can be detected. This paper presents a method to judge the type of detected defects automatically, and to display them three-dimensionally. The defect type is classified as unconnected defect, void, and so on, based on location, size, and shape information of defect. Three-dimensional display which is realized using OpenGL (Open Graphics Library) will be helpful to understand the overall situation including location, size, shape of the defects in a test object.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.195-198
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• 2001

Backside defect of plate structure may grow due to fatigue or overload to cause critical failure during operation, so it is important to detect this kind of defect in line. For this purpose, nondestructive, non-contact and highly sensitive method is required. ESPI and Shearography are considered as useful method to satisfy these requirements. In this paper, the possibility of application of ESPI and Shearography to detect the backside defect of steel plate and to quantify the defect size was tested. For the experiment, some steel plates with defect on the backside were prepared. Experimental results for these plates showed that location and size of defect could be detected correctly by both of ESPI and Shearography.

• Clinical and Experimental Pediatrics
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• 제46권9호
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• pp.871-875
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• 2003

목 적 : 소아에서 두 번째로 빈도가 높은 심방 중격 결손의 조기진단이 점차 증가하면서 그 자연 경과에 대한 재조명이 이루어지고 있으나 아직 미흡한 부분이 많으며 특히 결손의 크기 변화가 어떻게 되는지에 대해 보고가 많지 않은 현실이다. 이에 저자들은 소아에서 다른 선천성 심질환이 없는 순수한 이차성 심방 중격 결손 환아의 심초음파 추적 관찰을 통해 성장에 따른 결손크기의 변화에 대해 알아보고자 본 연구를 시행하였다. 방 법 : 1996년 1월부터 2000년 12월까지 5년간 연세 심장 혈관 병원 심장 소아과에서 새롭게 심방 중격 결손증으로 진단 받은 272명의 환아 중 다른 선천성 심질환이 있거나, 추적 관찰기간이 12개월 미만이었거나, 추적 관찰 도중 어떠한 이유든 수술이나 중재적 심도자술을 시행 받은 환아들을 제외한 89명을 대상으로 심초음파적 추적 관찰을 시행하였다. 심초음파적 크기는 늑골하 장, 단축면상에서 얻은 것으로 통일하였다. 진단 시 결손크기에 따라, 나이에 따라 각각 4개 군으로 나누어 각각의 군에서 결손의 자연 폐쇄 여부와 시간경과에 따른 결손의 크기변화(mm/월)를 알아보았다. 또한 폐쇄군과 비폐쇄군으로 나누어 각각의 군의 특징에 대해서 알아보았다. 결 과 : 대상 환아 89명 중 결손의 크기가 5 mm 미만인 군은 총 25명(28%), 이중 22명(88%)이 자연폐쇄 되었으며 평균 결손의 크기 변화는 -0.206(mm/월)이었다. 5-8 mm인 군은 총 22명(24.7%), 이중 10명(45.5%)이 자연 폐쇄되었으며 평균 결손의 크기변화는 -0.067이었다. 9-12 mm인 군은 총 26명(29.3%), 이중 3명(11.5%)이 자연 폐쇄되었으며 평균 결손의 크기변화는 +0.058이었다. 12 mm 초과인 군은 총 16명(18%), 이중 자연폐쇄는 없었으며 평균 결손의 크기변화는 +0.155이었다. 연령에 따른 분류에서 1, 2, 3, 5세를 기준으로 각각 기준 이하와 초과의 군으로 나누었을 때 3세까지는 자연 폐쇄와 결손의 크기변화가 통계학적으로 유의하게 차이가 있었으며(P<0.05) 5세가 되면 차이가 없어지는 것으로 조사되었다. 결손이 폐쇄된 군은 총 35명(39.3%), 폐쇄되지 않은 군은 54명(60.7%)으로 두 군 사이의 통계학적 차이는 진단 시 결손의 크기였다. 비폐쇄군의 절대적인 결손 크기변화는 +0.116(mm/월)으로서 통계학적으로 의미 있게 결손의 크기가 증가된 것으로 조사되었으나(P<0.005), 이를 체표면적으로 환산하였을 경우 통계학적 의미는 없었다. 결 론 : 소아의 단순 심방 중격 결손증에서 첫 진단 시 결손의 크기가 작을수록, 연령이 어릴수록 자연 폐쇄의 가능성이 높으며 자연 폐쇄되지 않는 경우 결손의 절대적 크기가 증가되나 체표면적으로 환산시 통계학적 의의는 없다. 결손의 자연 폐쇄는 평균 26.2개월에 이루어져 진단 후 약 2년 이상의 추적관찰이 필요하다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제42권1호
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• pp.20-30
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• 2016

Objectives: To validate a critical-size mandibular bone defect model in miniature pigs. Materials and Methods: Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks. Results: In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect. Conclusion: The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.

• 한국해양공학회지
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• 제1권2호
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• pp.74-82
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• 1987

This study has been made to investigate into the behavior of fatigue limit, of fatigue crack initiation, and of fatigue crack propagation under the condition of rotating bending stress; specifically on the independency of stress field as well as the crack behavior of surface micro hole defect, which is made artificially through the specimen. The results obtained can be summarized as followa; 1) For the single micro hole defect, initiation of fatigue crack is occurred at both tips of microhole defect simultaneosly along the slip which are produced in the range of maximum principal stress arround micro hole defect independent of the size of micro hole defect. 2) For the neighbored deuble micro hole defects with equal size, in the range ($\frac{L}{r}$)ratio $\gtrsim$ 3 defined as the size of micro hole defect(2r) to the distance between the centers of micro hole defects (2L), the crack behavior of the micro hole defects is same as single one. However, for the range of $\frac{L}{r}$<3, the interference effect becomes significant as the ratio approaches to 1.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권4호
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• pp.486-490
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• 2013

A defect which is axially oriented with small size is hard to detect in conventional system. CMFL(Cricumferential Magnetic Flus Leakage) type PIG(Pipelines Inspection Gauge) in the NDT(Nondestructive Testing), is operated to detect this defect called axially oriented cracks in the pipe. It is necessary to decompose the size and shapes of cracks for the manintenance of underground pipelines. This article is focused on the decomposing method of the size and shape of the axially oriented cracks by using inspection signal data for defect.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.163-165
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• 2009

Automatic Vision Inspection(AVI) systems automatically detect defect features and measure their sizes via camera vision. It is important to predict the performance of an AVI to meet customer's specification in advance. In this paper, we propose a statistical method for prediction of false alarm rate regarding inconsistency of defect size measuremet process. We only need are a simple experimental trial for repeated defect size measurement test. The statistical features from the experiement are utilized in the prediction process. Therefore, the proposed method is swift and easy to implement and use. The experiment shows a close prediction compared to manual inspection results.

• Archives of Reconstructive Microsurgery
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• 제25권2호
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• pp.25-28
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• 2016

Purpose: Reconstruction of small defects of the dorsal fingers and toes is a challenging task. Although adipofascial flap is widely used for these areas, additional refinements are warranted. In this paper, we define the appropriate defect size in the finger and toes that can be treated with the adipofascial flap, refine its surgical indications and present a few surgical tips. Materials and Methods: Twelve patients with dorsal defects of the fingers and toes were treated with a random-type adipofascial turn-over flap and skin graft. If the defect area exceeded the size that could be covered by a conventional design, the flap base was designed in oblique or curvilinear fashion to lengthen the flap. For accurate defect coverage, the width of the flap base was designed in an asymmetrical shape depending on the defect configuration, varying the width from 0.3 to 1.0 cm, as opposed to the standard 0.5 to 1.0 cm width. Moreover, the lateral limit of the flap was defined as the lateral axial line. The size of the defect ranged from $3.0{\times}1.7cm$ to $1.5{\times}1.3cm$. Results: All flaps survived completely. Gliding function of the hand was well preserved and there was no evidence of tendon adhesion. Conclusion: The small defect in the dorsal finger and toe can be defined as less than one phalanx-length, measuring about $3.0{\times}2.0cm$ in size. If the defect exceeds this dimension, it is recommended that a different option be considered. We believe the adipofascial flap is an excellent option for treating small defects.