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متن کامل


اطلاعات دوره: 
  • سال: 

    0
  • دوره: 

    -
  • شماره: 

    11
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    2
  • بازدید: 

    525
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 525

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نویسندگان: 

SHAHDOOSTI H.R. | GHASSEMIAN H.

اطلاعات دوره: 
  • سال: 

    2011
  • دوره: 

    11
  • شماره: 

    3
  • صفحات: 

    19-27
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    371
  • دانلود: 

    0
چکیده: 

An ideal fusion method preserves the spectral information in fused image without spatial distortion. The PCA is believed to be a well-known pan-sharpening approach and being widely used for its efficiency and high spatial resolution. However, it can distort the spectral characteristics of multispectral images. The current paper tries to present a new fusion method based on the same concept. In the conventional standard PCA method, PCA transform is applied to spectral bands of multispectral images, but we applied the PCA transform to pixel blocks instead. Since PCA coefficients are extracted from statistical properties of the image, it is more consistent with type and texture of remotely sensed image compared to other kernels such as wavelets. After that, a new hybrid algorithm is proposed which uses both the spatial PCA and the spectral PCA method to improve the quality of the merged images. Visual and statistical analyses show that the proposed algorithm clearly improves the merging quality in terms of RASE, ERGAS, SAM, correlation coefficient and UIQI; compared to fusion methods such as IHS, Brovey, PCA, HPF, and HPM.

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بازدید 371

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نویسندگان: 

OFTADEH M. | MADADI MAHANI N.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    2
  • شماره: 

    2
  • صفحات: 

    131-136
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    350
  • دانلود: 

    0
چکیده: 

To improve drug selectivity toward target cells, one interesting approach for drug delivery is to use polymer nanoparticles. A two-layered ONIOM Becke3-LYP: UFF calculation was carried out to study the structural and thermodynamic properties of the interaction between acetamide derivatives and the PCA-PEG-PCA copolymers. The Interaction enthalpies and the Gibbs free energies between acetamide derivatives as anti-HIV and polymeric nanoparticles in the gas and solution phases were calculated. The structure as well as the thermodynamics of optimized complexes was discussed from the biological point of view. In the gas phase, substitutes of phenyl, flurophenyl, 4-acetyl-2-bromophenyl, and 3-methyl-acetate-thiophen-2-yl had the highest energies, and in the water phase, the enthalpies and Gibbs free energies of the interaction for most compounds were almost identical. In the both phases the interaction is relatively weak and copolymers can be used for drug delivery.

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
نویسنده: 

Shabbak A. | Khakestari M.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    12
تعامل: 
  • بازدید: 

    162
  • دانلود: 

    0
چکیده: 

THE CLASSICAL MULTIVARIATE HOTELLING T 2 CONTROL CHART, WHICH IS WIDELY USED IN PRACTICE, IS VERY SENSITIVE TO THE DEVIATION FROM MULTIVARIATE NORMAL DISTRIBUTION, ESPECIALLY AS A RESULT OF OUTLIERS. ALTERNATIVELY THE ROBUST VERSION OF THIS CONTROL CHART WHICH ARE USUALLY BASED ON ROBUST ESTIMATORS OF LOCATION AND DISPERSION PARAMETERS, ARE USED TO REMEDY THIS PROBLEM. TWO OF THE MOST IMPORTANT OF THESE ROBUST ESTIMATORS ARE MINIMUM VOLUME ELLIPSOID (MVE) AND MINIMUM COVARIANCE DETERMINANT (MCD). ALTHOUGH THE ROBUST MULTIVARIATE CONTROL CHARTS, HAVE AN ACCEPTABLE PERFORMANCE IN LOW VARIABLES DIMENSION SPACE, THEIR CAPABILITY OF OUTLIERS' DETECTION DECREASE AS THE NUMBER OF VARIABLES INCREASES. DUE TO THIS REASON IN THIS PAPER, THE PRINCIPAL COMPONENT ANALYSIS (PCA) IS SUGGESTED TO EMPLOY AS A STATISTICAL TECHNIQUE FOR REDUCING THE DIMENSION OF DATASET.

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بازدید 162

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نویسندگان: 

MINKA T.P.

اطلاعات دوره: 
  • سال: 

    2000
  • دوره: 

    -
  • شماره: 

    514
  • صفحات: 

    1-16
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    194
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 194

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اطلاعات دوره: 
  • سال: 

    1385
  • دوره: 

    2
تعامل: 
  • بازدید: 

    1520
  • دانلود: 

    420
چکیده: 

در این مقاله مدلی جهت ارزیابی تامین کنندگان با استفاده از روش (Principle Component Analysis) PCA ارایه شده است. این مدل به رتبه بندی تامین کنندگان با توجه به شاخص های مدل می پردازد. این روش در یک شرکت تولیدی پیاده سازی شده است.

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بازدید 1520

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
نویسندگان: 

Yazdani Hamid Reza | Shojaeifard Ali Reza

اطلاعات دوره: 
  • سال: 

    2023
  • دوره: 

    4
  • شماره: 

    1
  • صفحات: 

    29-35
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    40
  • دانلود: 

    0
چکیده: 

Face recognition is an essential field of image processing and computer vision. In this paper, we have developed a facial recognition system that can detect and recognize the face of a person by comparing the characteristics, and features of the face to those of known faces. Our approach considers the face recognition problem as an intrinsically two-dimensional recognition problem rather than requiring recovery of three-dimensional geometry, considering that eigenvectors generally describe human faces in the face space. The system works by projecting face images onto a feature space that spans the significant variations among known face images that are called eigenvectors (or principal components of the face set). Our technique can learn and recognize new faces in an unsupervised style—this approach is based on eigenfaces and principal component analysis (PCA).

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اطلاعات دوره: 
  • سال: 

    1395
  • دوره: 

    13
  • شماره: 

    56
  • صفحات: 

    143-153
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1047
  • دانلود: 

    432
چکیده: 

بازرسی ترک پوسته تخم مرغ در گذشته به طور معمول در صنعت با نورآزمایی صورت می گرفته است. این عمل با گذر زمان سبب خستگی چشم، قضاوت نادرست و تشخیص سخت ترک های موئی می گردد. پژوهش های اخیر به مطالعه تشخیص ترک پوسته تخم مرغ بر اساس تشخیص نوری و مکانیکی به طور خودکار متمرکز می باشد. در این پژوهش، پوسته تخم مرغ ها به وسیله یک ضربه زن مکانیکی سبک در مکان های مختلف تحریک شدند و پاسخ فرکانسی ارتعاش پوسته تخم مرغ همراه با شناسایی الگو برای تشخیص تخم مرغ سالم از ترک دار استفاده گردید. روش های شناسایی الگو مورد استفاده PCA و SVM بودند. تعداد بهینه مولفه های اصلی با توجه به مقدار خطای مدل پیشگو و حداکثر تمییز میان تخم مرغ سالم از ترک دار 7 بدست آمد. نتایج پژوهش نشان داد که روش تحلیل ارتعاشی پاسخ ضربه پوسته توانایی تشخیص تخم مرغ سالم و با پوسته ترک دار به ترتیب با دقت 100% و %87.5 را دارد.

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نشریه: 

علوم کشاورزی

اطلاعات دوره: 
  • سال: 

    1378
  • دوره: 

    5
  • شماره: 

    18-17
  • صفحات: 

    43-62
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    464
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 464

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نشریه: 

AMIRKABIR

اطلاعات دوره: 
  • سال: 

    2008
  • دوره: 

    18
  • شماره: 

    67-A (TOPICS IN: GROUPS OF ENGINEERING, ELECTRONIC, BIOMEDICAL, COMPUTER)
  • صفحات: 

    25-33
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    274
  • دانلود: 

    0
چکیده: 

In this paper, an efficient method is proposed for load estimation of distribution networks with limited real-time data based on principal component analysis. The principal components of load variables are first detected off-line from historical data. Next, the interrelations between the load variables are developed using a new concept that we call Inverse PCA (IPCA) method; this leads to some proper models devised so that the distribution network becomes observable. Finally, through incorporation of a certain finite set of real time data measurements, the loads of all network nodes in real-time are estimated with a desired degree of accuracy via the IPCA method. A case study on a real network is considered in the paper to highlight better the merit of the proposed method. The experimental results easily show that the proposed method outperforms the previously cited techniques.

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بازدید 274

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