• 한국재료학회지
• /
• 제15권6호
• /
• pp.370-374
• /
• 2005

Doppler broadening spectrometer for positron annihilation experiment(DBPAS) has been used to characterize nano size defect structures in materials. DBPAS measures the concentration, spatial distribution, and size of open volume defects in the rare-earth intensifying screen materials. The screens were exposed by X-ray varying the exposed doses from 3, 6, 9, and 12 Gy with 6 W and 15 MV respectively and also irradiated by 37 MeV proton beams ranging from 0 to $10^{12}ptls$. The S parameter values increased as the exposed time and the energies increased, which indicated the defects were generated more. The S parameters of the samples with X-rays varied from 0.5098 to 0.5108, on the other hand, as proton beams varied from 0.4804 to 0.4821.

• 한국진공학회지
• /
• 제13권2호
• /
• pp.92-98
• /
• 2004

양전자 소멸 분광법으로 시료에서 원자 크기 정도 결함의 특성을 조사하였다. 양전자와 전자의 쌍소멸에서 발생하는 511 KeV 감마선 스펙트럼의 수리적 해석 방법인 S-변수를 사용하여, 결함의 정도를 측정하였다. 임상에서 X-선 증감지로 0, 2, 4, 6년 동안 사용한 시료를 실험하였다. 각 시료들에서 측정된 S-변수는 0.4932부터 0.4956 정도의 변화를 보였다. 이에 상응하는 실험 방법으로 같은 시료에 X-선의 에너지와 조사시간 즉 6 MV 및 15 MV의 X-선을 사용하여 3, 6, 9, 그리고 12 Gy의 조사량을 변화시키면서 결함의 정도를 측정 비교하였다.

• 정보과학회 컴퓨팅의 실제 논문지
• /
• 제22권12호
• /
• pp.681-686
• /
• 2016

소프트웨어 결함 예측은 프로젝트의 효율적인 관리와 성공에 있어 중요한 요소이다. 이 결함은 심각도에 따라 프로젝트에 영향을 미치는 정도가 다르다. 그러나 기존 연구는 결함 유무만 관심을 두고 심각도를 고려하지 않는다. 본 논문에서는 소프트웨어 관리 효율과 품질 향상을 위해 FCM을 적용한 결함 심각도 기반 앙상블 모델을 제안한다. 제안된 모델은 FCM으로 NASA PC4의 결함심각도를 재분류한다. 그리고 RF(Random Forest)로 심각도에 영향을 주는 입력 column을 선별하여 데이터 핵심 결함 요인을 추출한다. 또한 10-fold 교차검증으로 파라미터를 변경해 모델 성능을 평가한다. 실험 결과는 다음과 같다. 첫째, 결함심각도가 58,40,80에서 30,20,128로 재분류되었다. 둘째, 심각도에 영향을 주는 중요한 입력 column은 정확도와 노드 불순도 측면에서 BRANCH_COUNT였다. 셋째, 성능평가는 트리수가 작고 고려할 변수가 많을수록 좋은 성능을 보였다.

• 한국재료학회지
• /
• 제12권5호
• /
• pp.359-362
• /
• 2002

DBPAS has been used to characterize atomic level defect structures in materials. In this investigation the numerical analysis of the Doppler spectra was restricted to the determination of the shape parameter, S, defined as the ratio between the total amount of counts in a central portion of the spectrum and the total amount of counts. As samples were exposed by X-ray increasing from 3, 6, and 9 Gy with 6 MV, and 10 MV each and also by E-beam increasing the energies with 6 MeV, 9 MeV, 12 MeV, and 20 MeV. The S-parameter values were increased as increasing the exposed time and the energies. The S-parameters of the large and small size grains in $CaWO_4$ were measured. The S-parameter of the small size grains in $CaWO_4$ was resulted in larger values.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2007년도 추계학술대회 논문집
• /
• pp.124-127
• /
• 2007

In this study, we focused on investigation of governing parameters affected on the fatigue properties in the hyper-eutectoid steel wires used for TBR tires. Steel wires are fabricated under different drawing strain from 3.36 to 3.80. Their diameters are 0.21 mm and 0.185mm, respectively. The fatigue properties was measured by hunter rotating beam tester, specially designed thin-sized steel wires. The results showed that the fatigue properites of steel wire, marked as A-1, were greater than the others, due to the low value of residual stress. In order to elucidate the variations of fatigue properties, the microstructure, surface defect and residual stress were observed and measured by useful analysis technique, such as TEM, 3D profiler and FIB.

• 제어로봇시스템학회논문지
• /
• 제14권5호
• /
• pp.415-419
• /
• 2008

Detecting and correcting defects on LCD glasses early in the manufacturing process becomes important for panel makers to reduce the manufacturing costs and to improve productivity. Many attempts have been made and were successfully applied to detect and identify simple defects such as scratches, dents, and foreign objects on glasses. However, it is still difficult to robustly detect low-contrast defect region, called Mura or blemish area on glasses. Typically, these defect areas are roughly defined as relatively large, several millimeters of diameter, and relatively dark and/or bright region of low Signal-to-Noise Ratio (SNR) against background of low-frequency signal. The aim of this article is to present a robust algorithm to segment these blemish defects. Early 90's, a highly robust estimator, known as the Model-Fitting (MF) estimator was developed by X. Zhuang et. al. and have been successfully used in many computer vision application. Compared to the conventional Least-Square (LS) estimator the MF estimator can successfully estimate model parameters from a dataset of contaminated Gaussian mixture. Such a noise model is defined as a regular white Gaussian noise model with probability $1-\varepsilon$ plus an outlier process with probability $varepsilon$. In the sense of robust estimation, the blemish defect in images can be considered as being a group of outliers in the process of estimating image background model parameters. The algorithm developed in this paper uses a modified MF estimator to robustly estimate the background model and as a by-product to segment the blemish defects, the outliers.

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

• Journal of Periodontal and Implant Science
• /
• 제39권4호
• /
• pp.385-390
• /
• 2009

Purpose: In this study we evaluated the morphologic aspects of defects created by a piezoelectric ultrasonic scaler with scaler tip on casting gold alloy using scanning electron microscope (SEM) images and defect surface profiles. Methods: 54 blocks of type III casting gold alloy (Firmilay, Jellenko Inc, CA, USA) were scaled by a piezoelectric ultrasonic scaler (P-MAX, Satelec, France) with scaler tip (No. 1 tip) on a sledge device. 2-dimensional profiles of defects on all samples were investigated by a surface profilometer (a-Step 500, KLA-Tencor, CA, USA). The selected working parameters were lateral force (0.5 N, 1.0 N, 2.0 N), mode (P mode, S mode), and power setting (2, 4, 8). SEM images were obtained. Defect surface profiles were made on Microsoft Excel program using data obtained by a surface profilometer. Results: Among P mode samples, there were similarities on defect surface profiles and SEM images regardless of lateral force. The defects created in P mode were narrow and shallow although the depth and the width increased as power setting changed low (2) to high (8). In P mode samples, the defect depth was the greatest when lateral force of 0.5 N was applied. However all the depths were smaller than 1 m. SEM images of Lateral force of 0.5 N, S mode, power setting 2 and 4 were similar to that of P mode, but the other SEM images of S mode showed discernible changes. Defect depth of S mode samples was the greatest when lateral force of 1.0 N was applied. Conclusions: Within the limitations of this study, it can be concoluded that removing capability of piezoelectric scaler with scaler tip becomes maximized as power level becomes higher but the capability is restricted when excessive lateral force is applied on scaler tip.

• 한국수자원학회논문집
• /
• 제36권2호
• /
• pp.223-235
• /
• 2003

Clark 모형의 매개변수 추정방법을 개선하기 위하여, 순간단위도를 gamma 분포형 함수로 가정하여 매개변수를 추정한 후 이를 Clark 모형의 매개변수로 전환하는 간접 추정방법을 제안하였다. 이 방법은 전통적인 Clark 모형의 매개변수 추정방법의 개연적인 부정확성을 개선하는 특징과 더불어 Nash 모형과의 상관성을 파악할 수 있는 장점을 갖고 있다. 제안된 매개변수 추정방법을 위천 유역에 적용한 결과 만족할 수 있는 수준의 추정값을 얻을 수 있었으며 또한 유역의 도달시간-유하면적 관계를 나타내는 합성함수를 구축할 수 있었다. 또한 제안된 매개변수 추정방법은 미계측 유역에 대한 추정에 있어서도 높은 적용성을 보였다. 따라서 제안된 방법론은 기존의 매개변수 추정방법을 보조할 수 있는 충분한 대안으로 판단된다.

• 치위생과학회지
• /
• 제15권2호
• /
• pp.98-105
• /
• 2015

본 연구는 외과적으로 형성된 흰쥐 하악골 결손부에 S.mutan에서 분리 정제된 mutan을 주사하고, ${\mu}CT$로 촬영하여 골결손부의 치유에 미치는 영향을 3차원 골 미세구조 지표로 평가하기 위하여 실시하였다. 흰쥐 치조골에 임계 크기 결손부인 1.5 mm 지름의 원형 결손부를 형성하여 대조군에는 동일량의 saline을 투여하고, 실험군으로 LPS와, mutan을 주사하여 골치유에 미치는 영향을 관찰하였다. 수술 후 4주에 희생하고 치유 결과를 3차원 미세구조의 형태 계측학적 지표값을 비교 분석하여 다음과 같은 결론을 얻었다. 실험동물의 체중변화는 총 12회 투여 기간 동안 일정한 증가를 나타냈다. 8회차부터 mutan 처리군은 대조군과 비교하여 유의한 차이를 보였으며(p<0.05), 9회차에는 mutan 처리군이 대조군과 LPS 처리군과 비교하여(p<0.05), 10~12회차에는 LPS 처리군과 비교하여 유의한 체중증가를 나타냈다(p<0.01). Mutan이 생체 내에서 하악의 골치유 효과를 알아보기 위해 ${\mu}CT$를 통해 형태계측학적 지표 분석 결과, 대조군에 비해 LPS 처리군에서 뚜렷한 골결손부 치유 지연 및 골흡수 양상을 보였으며, mutan 처리군 은 LPS의 작용보다 미약하지만 골치유를 지연시키는 것으로 확인되었다. ${\mu}CT$를 통해 골밀도 분석 결과, 대조군과 비교하여 LPS와 muatn 처리군에서 낮은 골밀도치를 나타냈고, mutan은 LPS 처리군보다 유의하게 높은 골밀도치를 보였다(p<0.01).