• 제목/요약/키워드: Scatter correction

검색결과 93건 처리시간 0.021초

CALIBRATION TRANSFER FROM REFLECTANCE TO INTERACTANCE-REFLECTANCE WITHOUT STANDARDS: USE OF MATHEMATICAL PRETREATMENTS

  • Fernandez Cabanas, Victor-M.;Varo, Garrido;Dardenne, Pierre
    • 한국근적외분광분석학회:학술대회논문집
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    • 한국근적외분광분석학회 2001년도 NIR-2001
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    • pp.1242-1242
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    • 2001
  • The use of fibre optic probes for NIR quality control in the industry is becoming very important, as it provides a powerful tool to reduce sample analysis time and it facilitates the implementation of on-line analyses. However, most of the applications of fibre optics and probes have been done on suspensions, clear liquids and films, chemical and pharmaceutical products and also on fruits and animal products. Traditional applications of near infrared spectroscopy in agriculture have been developed in reflectance mode and calibration transfer could be an interesting way to reduce efforts. Classical methods for calibration transfer between different instruments involve the use of sealed reference cups, but, as fibre optic analysis does not use cups, it is necessary to develop new methods for calibration transfer without standards (Blank et al., 1996). In this paper, we have studied how the most used mathematical pretreatments (three methods of Multiplicative Scatter Correction, Standard Normal Variate, Detrending and derivatives) and their combinations applied to calibration development can contribute to reduce spectral differences between instruments. Calibration equations were obtained for three sets of cereals (barley, wheat and maize) scanned in reflectance mode and then they were validated with samples analysed in reflectance and interactance-reflectance mode (fibre optic). Preliminary results show how some combination of pretreatments reduce the differences in the predicted values, measured as standard error of differences, facilitating the use of calibrations obtained in reflectance for samples analysed by interactance-reflectance. However, the application of pretreatments is not enough to satisfy the control limits for calibration transfer suggested by Shenk et al. (1992), and it should be necessary to combine them with a specific algorithm for instruments standardization.

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확장된 SSD에 기인한 Electron beam의 Output 및 특성 변화에 관한 연구 (A Study on clinical Considerations caused by inevitably Extended SSD for Electron beam therapy)

  • 이정우;김정만
    • 대한방사선치료학회지
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    • 제8권1호
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    • pp.29-35
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    • 1996
  • We are often faced with the clinical situations that is inevitably extended SSD for electron beam therapy due to anatomical restriction or applicator structure. But there are some difficulties in accurately predicting output and properties. In electron beam treatment , unlike photon beam the decrease in output for extended SSD does not follow inverse-square law accurately because of a loss of side scatter equilibrium, which is particularly significant for small cone size and low energies. The purpose of our study is to analyze the output in changing with the energy, cone size, air gap beyond the standard SSD and to compare inverse-square law factor derived from calculated effective SSD, mominal SSD with measured output factor. In addition, we have analyzed the change of PDD for several cones with different SSDs which range from 100cm to 120cm with 5cm step and with different energies(6MeV, 9MeV, 12MeV, 16MeV, 20MeV). In accordance with our study, an extended SSD produces a significant change in beam output, negligible change in depth dose which range from 100cm to 120cm SSDs. In order to deliver the more accurate dose to the neoplastic tissue, first of all we recommend inverse-square law using the table of effective SSDs with cone sizes and energies respectively or simply to create a table of extended SSD air gap correction factor. The second we need to have an insight into some change of dose distribution including PPD, penumbra caused by extended SSD for electron beam therapy.

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전문간호사 역할의 중요도, 만족도 및 기여도에 대한 의료인의 인식 - 전문의, 간호사, 전문간호사를 대상으로 - (Importance, Satisfaction and Contribution of Advanced Practice Nurses' Role Recognized by Health Care Professionals)

  • 조명숙;조용애;권인각;서민정;백혜진
    • 간호행정학회지
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    • 제17권2호
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    • pp.168-179
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    • 2011
  • Purpose: The purpose of this study was to identify level of recognition of the importance, satisfaction and contribution of APNs' role by physicians, nurses, and advanced practice nurses. Method: Perceived importance and satisfaction were measured with a 23-item questionnaire on APN role with 5 subcategories. APNs' contribution was investigated using a 13-item outcome questionnaire developed by the researchers. Between August 15 and October 31, 2009, the researchers collected data from 68 physicians, 265 nurses, and 23 APNs all working in a single tertiary hospital. Data were analyzed using descriptive statistics, Kruskal-Wallis Test with Bonferroni's Correction and scatter plot. Result: The importance (3.24~3.39, 4 point scale), satisfaction (3.02~3.13, 4 point scale), and contribution of APNs' role (3.39~4.12, 5 point scale) were well recognized by the health care professionals. All the three health care professional groups rated APNs' contribution high in medical service management, continuity of care, patient accessibility, improvement in patient satisfaction, and patient and family education. 'Importance-Satisfaction Analysis' showed that patient data management by APNs needed greater effort. Conclusions: The findings show that the importance, satisfaction, contribution of APNs' role are recognized, and indicate a need for further development of APNs' role through efforts to overcome the gaps identified through this research.

Non-destructive Method for Selection of Soybean Lines Contained High Protein and Oil by Near Infrared Reflectance Spectroscopy

  • Choung, Myoung-Gun;Baek, In-Youl;Kang, Sung-Taeg;Han, Won-Young;Shin, Doo-Chull;Moon, Huhn-Pal;Kang, Kwang-Hee
    • 한국작물학회지
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    • 제46권5호
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    • pp.401-406
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    • 2001
  • The applicability of non-destructive near infrared reflectance spectroscopic (NIRS) method was tested to determine the protein and oil contents of intact soybean [Glycine max (L.) Merr.] seeds. A total of 198 soybean calibration samples and 101 validation samples were used for NIRS equation development and validation, respectively. In the developed non-destructive NIRS equation for analysis of protein and oil contents, the most accurate equation was obtained at 2, 8, 6, 1(2nd derivative, 8 nm gap, 6 points smoothing, and 1 point second smoothing) and 2, 1, 20, 10 math treatment conditions with Standard Normal Variate and Detrend (SNVD) scatter correction method and entire spectrum (400-2500 nm) by using Modified Partial Least Squares (MPLS) regression, respectively. Validation of these non-destructive NIRS equations showed very low bias (protein: 0.060%, oil: -0.017%) and standard error of prediction (SEP, protein: 0.568 %, oil : 0.451 %) as well as high coefficient of determination ($R^2$, protein: 0.927, oil: 0.906). Therefore, these non-destructive NIRS equations can be applicable and reliable for determination of protein and oil content of intact soybean seeds, and non-destructive NIRS method could be used as a mass screening technique for selection of high protein and oil soybean in breeding programs.

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특징 추출을 이용한 다중 영상 정합 및 융합 연구 (Multimodality Image Registration and Fusion using Feature Extraction)

  • 우상근;김지현
    • 한국컴퓨터정보학회논문지
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    • 제12권2호
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    • pp.123-130
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    • 2007
  • 본 논문에서는 소동물 생체내 실험시 서로 다른 장비에서 획득된 영상의 융합 및 정합을 위한 방법을 제안한다. 마우스의 꼬리 정맥에 $[[^{18}F]FDG$를 주사하여 60분 섭취후 서로 다른 장비에서 동일한 위치의 영상을 획득하기 위하여 아크릴 재질의 소동물 가이드에 기준마크를 설정하고 microPET과 CT 영상을 획득하였다. MicroPET으로 획득된 리스트모드(list-mode) 데이터는 Fourier Rebinning(FRB) 방법을 사용하여 사이노그램(Sinogram)으로 변환 후 4 번의 반복횟수를 가지는 Ordered Subset Expectation Maximization(OSEM) 알고리즘으로 재구성하였다. MicroPET 영상획득후 PET/CT의 CT를 이용하여 CT영상을 획득하였다. MicroPET 영상에서 폐영역을 정확히 찾아내는 어려움이 있어. 해부학적 정보를 제공하는 CT 영상을 이용하여 폐 영역을 구분하였다. 영상 융합을 위한 불일치 부분을 해결하기 위하여 기준마크의 정보와 폐 영역의 정보를 이용하여 회전과 이동정보를 가지는 어파인 (affine) 변환 행렬 구하여 영상 정합에 사용하였다. 이 방법은 정량적 정확성과 영상 해석의 정확성을 개선할 것으로 기대된다.

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부분용적효과 제거를 위한 Filter 구현 (Implementation of Filter for the Removal of Partial Volume Effect)

  • 박민주;이상복
    • 한국방사선학회논문지
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    • 제9권3호
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    • pp.139-145
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    • 2015
  • SPECT를 이용한 환자의 검사 시 몸 안에서 방출되는 ${\gamma}$-선은 감쇠 또는 산란 등의 현상이 일어나며, 검출기에 도달할 때 조준기의 물리적 특성과 기학적인 모양에 따라 퍼지는 현상이 발생하여 정량분석이 불가능하였다. 체내에서 방출되는 ${\gamma}$-선의 정확한 정량분석을 위해서는 반드시 부분용적효과에 대한 보정이 고려되어야 한다. 본 논문에서는 SPECT의 종합적인 부분용적효과를 해결하기 위하여 Sinogram Filter를 구현하였다. 구현된 Filter를 적용하여 실험을 한 결과, SPECT에서 발생되는 부분용적효과를 제거하였다. 기존방법과 제안한 방법을 비교하기 위하여 PSNR을 시행한 결과 제안한 방법으로 한 경우 PSNR은 7 dB, 기존방법은 14 dB로 나왔다. 제안한 방법의 dB이 낮아진 이유는 산란선 제거를 많이 하여 MSE가 높아지기 때문에 PSNR값이 낮게 나타났다. 따라서 제안한 방법을 적용한다면 SPECT 영상의 부분용적효과를 제거하여 영상의 질이 좋아질 것이다.

근적외선을 이용한 온라인 석탄 성상분석 방법 (The Technology for On-line Measurement of Coal Properties by using Near-Infrared)

  • 김동원;이종민;김재성;김학종
    • Korean Chemical Engineering Research
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    • 제45권6호
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    • pp.596-603
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    • 2007
  • 실시간 온라인 석탄 성상분석은 효율적인 석탄 화력발전소 운영을 위해 반드시 필요한 기술이다. 온라인 석탄 성상분석 기술 개발을 위해 다변량 분석기법을 사용하여 확산 반사방식을 통해 얻은 석탄의 근적외선 스펙트럼과 석탄 성상(%)[수분, 회분, 휘발분, 고정탄소, 탄소, 수소, 질소, 산소, 황], 발열량(kcal/kg)간의 관계를 조사하였다. 현재 석탄 화력발전소에서 사용하는 40여종의 석탄에서 얻은 근적외선 스펙트럼을 전처리[2차 미분, MSC(multiplicative scatter correction)]를 통해 물리적 영향을 최소화하여 석탄 성상과의 관계를 PLS(partial least squares regression), PCA(principal component analysis)의 chemometrics 기법을 이용하여 정량 분석하였다. 분석 결과 본 기법을 통해 근적외선 스펙트럼으로 석탄 성상 중 회분, 질소 그리고 황을 제외한 나머지 성분에 대해 분석이 가능함을 확인할 수 있었다. 또한 PC(PLS component)의 값을 이용하여 석탄의 종류를 구별한 다음, 다변량 통계기법을 사용하여 정량 분석한 결과, 전체 석탄을 이용해서 정량 분석한 결과에 비해 비교적 좋은 결과를 얻었다. 수분, 발열량이 실시간으로 분석 가능하여 보다 효율적인 석탄 화력발전소 운영이 가능할 것으로 예상된다.

Discriminant analysis of grain flours for rice paper using fluorescence hyperspectral imaging system and chemometric methods

  • Seo, Youngwook;Lee, Ahyeong;Kim, Bal-Geum;Lim, Jongguk
    • 농업과학연구
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    • 제47권3호
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    • pp.633-644
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    • 2020
  • Rice paper is an element of Vietnamese cuisine that can be used to wrap vegetables and meat. Rice and starch are the main ingredients of rice paper and their mixing ratio is important for quality control. In a commercial factory, assessment of food safety and quantitative supply is a challenging issue. A rapid and non-destructive monitoring system is therefore necessary in commercial production systems to ensure the food safety of rice and starch flour for the rice paper wrap. In this study, fluorescence hyperspectral imaging technology was applied to classify grain flours. Using the 3D hyper cube of fluorescence hyperspectral imaging (fHSI, 420 - 730 nm), spectral and spatial data and chemometric methods were applied to detect and classify flours. Eight flours (rice: 4, starch: 4) were prepared and hyperspectral images were acquired in a 5 (L) × 5 (W) × 1.5 (H) cm container. Linear discriminant analysis (LDA), partial least square discriminant analysis (PLSDA), support vector machine (SVM), classification and regression tree (CART), and random forest (RF) with a few preprocessing methods (multivariate scatter correction [MSC], 1st and 2nd derivative and moving average) were applied to classify grain flours and the accuracy was compared using a confusion matrix (accuracy and kappa coefficient). LDA with moving average showed the highest accuracy at A = 0.9362 (K = 0.9270). 1D convolutional neural network (CNN) demonstrated a classification result of A = 0.94 and showed improved classification results between mimyeon flour (MF)1 and MF2 of 0.72 and 0.87, respectively. In this study, the potential of non-destructive detection and classification of grain flours using fHSI technology and machine learning methods was demonstrated.

Ionospheric peak parameter foF2 and its variation trend observed by GPS

  • Jin, Shuanggen;Park, Jong-Uk;Park, Pil-Ho;Choi, Byung-Kyu
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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    • pp.181-184
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    • 2006
  • Knowledge of the ionospheric peak parameter foF2 (the critical frequency of F2 layer) is one of key essential factors for predicting ionospheric characteristics and delay correction of satellite positioning. However, the foF2 was almost estimated using an empirical model of International Reference Ionosphere (IRI) or other expensive observing techniques, such as ionosondes and scatter radar. In this paper, the ionospheric peak parameter foF2 is the first observed by ground-based GPS with all weather, low-cost and near real time properties. Compared with the IRI-2001 and independent ionosondes at or near the GPS receiver stations, the foF2 obtained from ground-based GPS is in better agreement, but closer to the ionosonde. However, during nighttime, the IRI model overestimated the GPS observed values during winter and equinox months.Furthermore, seasonal variation trend of the foF2 in 2003 is studied using foF2 monthly median hourly data measured over South Korea. It has shown that the systematic diurnal changes of foF2 are apparent in each season and the higher values of foF2 are observed during the equinoxes (semiannual anomaly) as well as in mid-daytime of each season.

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지상용 초분광 스캐너를 활용한 사과의 당도예측 모델의 성능향상을 위한 연구 (Study of Prediction Model Improvement for Apple Soluble Solids Content Using a Ground-based Hyperspectral Scanner)

  • 송아람;전우현;김용일
    • 대한원격탐사학회지
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    • 제33권5_1호
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    • pp.559-570
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    • 2017
  • 본 연구에서는 야외에서 자료 취득이 가능하며 한 번에 다량의 사과를 촬영할 수 있는 지상용 초분광 스캐너를 활용하여 사과의 분광정보와 당도와의 부분최소제곱회귀분석(PLSR, Partial Least Square Regression)을 수행하였으며, 최적의 예측모델을 구축하기 위한 다양한 전처리기법의 적용가능성을 평가하고 VIP(Variable Importance in Projection)점수를 통한 최적밴드를 산출하였다. 이를 위하여 360-1019 nm영역에서 촬영된 515밴드의 초분광 영상에서 70개의 분광곡선을 취득하였으며, 디지털광도계를 이용하여 당도($^{\circ}Brix$)를 측정하였다. 사과의 분광특성과 당도사이의 회귀모델을 구축하였으며, 최적의 예측모델은 모델 예측치와 실측치간의 결정계수($r_p^2$, coefficient of determination of prediction)와 RMSECV(Root Mean Square Error of Cross Validation), RMSEP(Root Mean Square Error of Prediction)등을 고려하여 선정하였다. 그 결과 산란보정 기법의 대표적인 MSC(Multiplicative Scatter Correction)의 기반의 전처리기법이 가장 효과적이었으며, MSC와 SNV(Standard Normal Variate)를 조합한 경우 RMSECV와 RMSEP가 각각 0.8551과 0.8561로 가장 낮았고, $r_c^2$$r_p^2$은 각각 0.8533과 0.6546으로 가장 높았다, 또한 360-380, 546-690, 760, 915, 931-939, 942, 953, 971, 978, 981, 988, 992-1019 nm 등이 당도 측정을 위한 가장 영향력 있는 파장영역으로 나타났다. 해당 영역의 분광값을 가지고 PLSR을 수행한 결과, 전파장대를 사용할 때보다 RMSEP가 0.6841로 감소하고 $r_p^2$는 0.7795로 증가하는 것을 확인하였다. 본 연구를 통하여 사과의 당도측정에 있어 야외에서 취득한 초분광 영상자료의 활용 가능성을 확인하였으며, 이는 필드자료 및 센서 활용분야의 확장가능성을 보여준다.