• 비파괴검사학회지
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• 제25권6호
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• pp.459-466
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• 2005

The scanning laser source (SLS) technique has been proposed recently as an effective way to investigate small surface-breaking defects, By monitoring the amplitude and frequency changes of the ultrasound generated as the SLS scans over a defect, the SLS technique has provided enhanced signal-to-noise performance compared to the traditional pitch-catch or pulse-echo ultrasonic methods, An extension of the SLS approach to map defects in microdevices is proposed by bringing both the generator and the receiver to the near-field scattering region of the defects, To facilitate near-field ultrasound measurement, silicon microcantilever probes are fabricated using microfabrication technique and their acoustical characteristics are investigated, Then, both the laser-generated ultrasonic source and the microcantilever probe are used to monitor near-field scattering by a surface-breaking defect.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1669-1680
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• 2010

The phase-shifted version of the multichannel quantum-defect theory (MQDT) was reformulated by disentangling the interloper spectrum from the perturbed dense Rydberg series for a systems involving 2 closed and more than 1 open channel. The theory was applied successfully to Martins and Zimmermann's photoionization spectra of the Rydberg series Cu I $3d^9\;4s(^1D_2)\;nd^2G_{9/2}$ perturbed by the interloper, $3d^9\;4p^2\;^4F_{9/2}$, for which Cohen's 4 channel QDT had failed. The zero surface graphic of the perturbed Fano's asymmetry parameter q of the autoionization spectrum of dense Rydberg series by the interloper was determined by only two parameters for this system. It was used as a map to trace the transformation route of the 3 channel autoionization spectra to the 4 channel spectra when the channel coupling of the closed channels with a newly added open channel was turned on progressively.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.88-93
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• 2021

The automotive industry is developing day by day. Among them, it is very important to prevent accidents while driving. However, despite the importance of developing automobile industry technology, accidents due to road defects increase every year, especially in the rainy season. To this end, we proposed a road defect detection system for road management by converging deep learning and raspberry pi, which show various possibilities. In this paper, we developed a system that visually displays through a map after analyzing the images captured by the Raspberry Pi and the route GPS. The deep learning model trained for this system achieved 96% accuracy. Through this system, it is expected to manage road defects efficiently at a low cost.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.204-204
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• 2004

현재 정보통신의 강국으로 손꼽히고 있는 국내에서도 FPD(Flat Panel Display) 장치를 첨단산업 핵심 기술로 보고 기업 간에 치열한 기술경쟁을 벌이고 있는 실정이다. 현재 양산단계까지 접어든 TFT-LCD(Tin Film Transistor Liquid Crystal Display)와 PDP(Plasma Display Panel)는 경량화, 박형화 등의 장점으로 전자업계에서 최고의 캐시카우(Cash Cow)로 부각되고 있으며, 특히 소비자들의 대화면 선호도의 증가 추세에 힘입어 LCD보다는 콘트라스트 비(Contrast Ratio)와 시야각(View Angle) 측면에 있어 FPD 장치의 대면적화 관점에서 유리한 PDP가 다소 우위를 보이고 있는 추세이다.(중략)

• 제어로봇시스템학회논문지
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• 제2권1호
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• pp.26-34
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• 1996

One of the challenging tasks in visual inspection using CCD camera is to identify surface defects in an image with complex textured backgeound. In microscopic view, the surface of real objects shows regular or random textured patterns. In this paper, we present a visual inspection algorithm to extract abnormal surface defects in an image with textured background. The algorithm uses the space and frequency information at the same time by introducing the Dominant Frequency Map(DFM) which can describe the frequency characteristics of every small local region of an input image. We demonstrate the feasibility and effectiveness of the method through a series of real experiments for a 14" TV CRT mold. The method successfully identifies a variety of infinitesimal defects, whose size is larger than $50\mu\textrm{m}$, of the mold. The experimental results show that the DFM based method is less sensitive to the environmental changes, such as illumination and defocusing, than conventional vision techniques.ques.

• Journal of Periodontal and Implant Science
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• 제48권5호
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• pp.305-316
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• 2018

Purpose: The aim of the present study was to evaluate the biocompatibility and barrier function of mussel adhesive protein (MAP)-loaded collagen membranes in guided bone regeneration (GBR). Methods: Eight male New Zealand white rabbits were used. Four circular defects (diameter: 8 mm) were created in the calvarium of each animal. The defects were randomly assigned to 1) a negative control group, 2) a cyanoacrylate (CA)-loaded collagen membrane group (the CA group), 3) a MAP-loaded collagen membrane group (the MAP group), and 4) a group that received a polycaprolactone block with MAP-loaded collagen membrane (the MAP-PCL group). Specimens were harvested at 2 weeks (n=4) and 8 weeks (n=4) postoperatively for observational histology and histometric analysis. Results: In the histologic analysis, MAP was completely absorbed without any byproducts. In contrast, some of the CA adhesive remained, showing an inflammatory reaction, at 8 weeks. In the MAP-PCL group, the MAP-loaded collagen membranes served as a barrier membrane despite their fast degradation in GBR. No significant difference was found in the amount of new bone between the MAP-PCL and MAP groups ($1.82{\pm}0.86mm^2$ and $2.60{\pm}0.65mm^2$, respectively). Conclusions: The MAP-loaded collagen membrane functioned efficiently in this rabbit calvarial GBR model, with excellent biocompatibility. Further research is needed to assess clinical applications in defect types that are more challenging for GBR than those used in the current model.

• 컴퓨터교육학회논문지
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• 제16권6호
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• pp.71-81
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• 2013

본 연구는 온라인 학습에서 콘텐츠의 제시유형과 제시수준, 그리고 학습자의 메타인지가 학습에 미치는 영향을 살펴보고자 실시되었다. 이를 위해 온라인 학습 콘텐츠의 제시유형과 제시수준, 그리고 학습자의 메타인지에 따른 개념도 형성과 학습 과정을 살펴보았다. 온라인 학습 콘텐츠의 제시유형은 의미중심형과 맥락중심형으로, 제시수준은 기본형과 결핍형으로 구분하여 제공하였고, 학습자의 메타인지는 검사결과에 따라 상하 두 집단으로 구분하였다. 연구결과는 콘텐츠의 제시유형에서 의미중심형(M=45.00, SE=1.97)이 맥락중심형(M=34.71, SE=1.98)보다 더 높은 개념도 형성을 보였다. 콘텐츠의 제시수준별 집단간(F=.002, p>.05), 메타인지 상하 집단간에는 의의 있는 차이가 없었다. 그러나 제시수준과 메타인지 사이에 상호작용(F=6.225, p<.05) 효과가 있어 메타인지 상집단은 결핍형에서, 하집단은 기본형에서 보다 높은 개념도 형성을 보였다. 또한 온라인 학습 과정 분석을 통해 학습자의 메타인지가 콘텐츠의 결점과 결핍을 보완하여 학습을 실행하게 하는 중요요인임을 확인할 수 있었다.

• 한국정밀공학회지
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• 제29권1호
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• pp.48-55
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• 2012

Pressure vessels in vehicle industries, power plants, and chemical industries are often affected by flaw and defect generated inside the pressure vessels due to production processes or being used. It is very important to detect such internal defects of pressure vessel because they sometimes bring out serious problems. In this paper, an optical defect detection method using digital shearography is used. This method has advantages that the inspection can be performed at a real time measurement and is less sensitive to environmental noise. Shearography is a laser-based technique for full-field, non-contacting measurement of surface deformation (displacement or strain). The ultimate goal of this paper is to detect flaws in pressure vessels and to measure the lengths of the flaws by using unwrapping, phase images which are only obtained by Phase map. Through this method, we could decrease post-processing (next processing). Real length of a pixel can be calculated by comparing minimum and maximum unwrapping images with shearing angle. Through measuring several specimen defects which have different lengths and depths of defect, it can be possible to interpret quantitatively by calculating gray level.

• 비파괴검사학회지
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• 제30권5호
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• pp.423-428
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• 2010

본 논문에서는 ESPI 방법을 이용하여 자동차 엔진의 핵심 부품인 TPS의 열변형력에 따른 변외변형을 측정하여 열변형 특성을 분석하였다. 높은 해상도의 CCD와 줌렌즈를 사용하여 부품의 검사영역을 가로 세로 각각 5cm로 최소화하였다. 주행거리가 다른 TPS 부품들을 4-step 위상이동법과 위상 연속화를 통해 변형량이 연속적으로 변하는 위상도를 얻었고, 3차원으로 변형의 모양과 크기를 나타내었다. 약 $70^{\circ}C$의 온도를 유지하면서 TPS 부품에 열을 가한 경우 주행거리가 길어질수록 TPS 변형은 크게 측정되었고, 위로 볼록한 형태로 변형되었다. 그리고 내부결함이 있는 부품에서는 위상도에 불연속적인 무늬가 나타났고, 아래로 오목한 모양을 갖는 변형으로 나타났다.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.192-199
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• 2016

With changes in insulated defects, the environment, and so on, new partial discharge (PD) data are highly different from the original samples. It leads to a decrease in on-line recognition rate. The UHF signal and pulse current signal of four kinds of typical artificial defect models in gas insulated switchgear (GIS) are obtained simultaneously by experiment. The relationship map of ultra-high frequency (UHF) cumulative energy and its corresponding apparent discharge of four kinds of typical artificial defect models are plotted. UHF cumulative energy and its corresponding apparent discharge are used as inputs. The support vector machine (SVM) incremental method is constructed. Examples show that the PD SVM incremental method based on simulated annealing (SA) effectively speeds up the data update rate and improves the adaptability of the classifier compared with the original method, in that the total sample is constituted by the old and new data. The PD SVM incremental method is a better pattern recognition technology for PD on-line monitoring.