نتایج جستجو برای: object scatter

تعداد نتایج: 310250  

1998
M S Brotherton Paul J Francis

Statistical investigations of samples of quasars have established that clusters of properties are correlated. The strongest trends among the ultraviolet emission-line properties are characterized by the object-to-object variation of emission from low-velocity gas, the so-called " intermediate-line region " or ILR. The strongest trends among the optical emission-line properties are characterized...

2007
Paul J. Francis

Statistical investigations of samples of quasars have established that clusters of properties are correlated. The strongest trends among the ultraviolet emission-line properties are characterized by the object-to-object variation of emission from low-velocity gas, the so-called \intermediate-line region" or ILR. The strongest trends among the optical emission-line properties are characterized b...

Journal: :Medical physics 2013
A Sisniega W Zbijewski A Badal I S Kyprianou J W Stayman J J Vaquero J H Siewerdsen

PURPOSE The proliferation of cone-beam CT (CBCT) has created interest in performance optimization, with x-ray scatter identified among the main limitations to image quality. CBCT often contends with elevated scatter, but the wide variety of imaging geometry in different CBCT configurations suggests that not all configurations are affected to the same extent. Graphics processing unit (GPU) accel...

Feature extraction performs an important role in improving hyperspectral image classification. Compared with parametric methods, nonparametric feature extraction methods have better performance when classes have no normal distribution. Besides, these methods can extract more features than what parametric feature extraction methods do. Nonparametric feature extraction methods use nonparametric s...

Ahmad Mostaar, Ghazaleh Sadrieh Khajoo Mahdi Salehi Barough Mohammad Ali Ostadrahimi

Introduction: In the last few decades, a lot of monte carlo codes have been introduced for medical applications. this is important because through simulation, we are fully independent of the spectral scattering factor that we are not able measure in real terms. The effect of the radiation energy, the dimension of the radiation field, the sensitive volume of the ion chamber on t...

Journal: :مدیریت صنعتی 0
علی مروتی شریف آبادی استادیار گروه مدیریت صنعتی، دانشکدۀ اقتصاد، مدیریت و حسابداری دانشگاه یزد، یزد، ایران مهناز باروت کوب کارشناس‎ارشد مدیریت صنعتی، دانشکدۀ اقتصاد، مدیریت و حسابداری دانشگاه یزد، یزد، ایران

one of methods of improvement of the material flow is cross docking that in is considered as a good method to reduce inventory and improve customer satisfaction. too, the vehicle routing problem is one of the important problems in distribution management and its goal is to find paths for delivering various cargos. therefore, this study was conducted in order to vehicle routing problem with cros...

Journal: :iranian journal of basic medical sciences 0
shabnam oloomi department of medical physics, mashhad university of medical science, mashhad, iran hadi noori eskandari department of applied mathematics, school of mathematical sciences, ferdowsi university of mashhad, mashhad, iran seyed rasoul zakavi nuclear medicine research center, imam reza hospital, faculty of medicine, mashhad university of medical sciences, mashhad, iran peter knoll department of nuclear medicine wilhelminenspital vienna, austria faraz kalantari research center for nuclear medicine, tehran university of medical sciences, tehran, iran mohsen hajizadeh saffar department of medical physics, mashhad university of medical science, mashhad, iran

objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...

Journal: :Astronomy and Astrophysics 2023

We investigate the statistical properties and origin of scatter within spatially resolved surface brightness profiles CHEX-MATE sample, formed by 118 galaxy clusters selected via SZ effect. These objects have been drawn from Planck catalogue cover a wide range masses, M$_{500}=[2-15] \times 10^{14} $M$_{\odot}$, redshift, z=[0.05,0.6]. derived emission measure determined full sample. found that...

2008
Robert E. Dickinson Liming Zhou Yuhong Tian Qing Liu Thomas Lavergne Bernard Pinty Crystal B. Schaaf Yuri Knyazikhin

[1] Advanced climate models require a more realistic description of canopy radiation with reasonable computational efficiency. This paper develops the mathematics of scattering from a spherical object conceptualized to be a spherical bush to provide a building block that helps to address this need of climate models. It is composed of a homogeneous distribution of individual smaller objects that...

Journal: :iranian journal of nuclear medicine 2013
mohsen hajizadeh saffar shabnam oloomi peter knoll hadi taleshi

introduction: scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. accurate estimation of scatter in projection data of spect is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. methods: the objective of this paper is to develop and validate a scatter correction technique ...

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