introduction: ordered subset expectation maximization (osem), is an effective iterative method for spect image reconstruction. the aim of this study is the evaluation of the role of system matrix in osem image reconstruction method using four different physical beam radiation models with three detection configurations. methods: spect was done with an arc of 180 degree in 32 projections after i...

A smooth solution { (t)}t∈[0,T ] ⊂ Rd of a parabolic geometric flow is characterized as the reachability set of a stochastic target problem. In this control problem the controller tries to steer the state process into a given deterministic set T with probability one. The reachability set, V (t), for the target problem is the set of all initial data x from which the state process Xν x(t) ∈ T for...

We consider the computation of an approximating curve to fit a given set of points. Such a curve fitting is a common problem in CAGD and we review three different approaches based upon minimization of the squared distance function: the point distance, tangent distance and squared distance error term. We enhance the classic setup comprising a point cloud and an approximating B-Spline curve by ob...

A constant envelope space-time modulation seems to be an attractive option especially for very high frequency and mobile applications because of its resistance to a nonlinear distortion. The paper first analyzes the mean squared distance of the constant envelope space-time modulated signal in a Rayleigh slowly flat fading spatial diversity channel with independent coefficients. It is shown that...

in this research, the spatial distribution of electrical conductivity and ph of springs, ghanats and the base flow concentration places on the streams of central and south-west and central parts of the hamedan-bahar plain were evaluated. using different geostatistical methods such as kriging, minimum curvature, inverse distance, natural neighbor, local polynomial and radial basis functions, 108...