Introduction: The main goal of SPECT imaging is to determine activity distribution inside the organs of the body. However, due to photon attenuation, it is almost impossible to do a quantitative study. In this paper, we suggest a mathematical relationship between activity distribution and its corresponding projections using a transfer matrix. Monte Carlo simulation was used to find a precise tr...

Given a complex Hilbert space H and the von Neumann algebra L(H) of all bounded linear operators in H, we study the Grassmann manifold M of all projections in L(H) that have a fixed finite rank r. To do it we take the Jordan-Banach triple (or JB *-triple) approach which allows us to define a natural Levi-Civita connection on M by using algebraic tools. We identify the geodesics and the Riemann ...

Let A be a von Neumann algebra acting in a separable complex Hilbert space H and let A be the set of all orthogonal projections (=idempotents) from A. A subset M ⊆ A is said to be ideal of projections if: a) p ≤ q where p ∈ A, q ∈ M ⇒ p ∈ M; b) p, q ∈ M and ‖pq‖ < 1 ⇒ p ∨ q ∈ M; c) sup{p : p ∈ M} = I. Put Mp := {q : q ∈ M, q ≤ p}, ∀p ∈ A . Note that A is the ideal of projections, 0 ∈ Mp, ∀p, an...

Sea-level rise due to both climate change and non-climatic factors threatens coastal settlements, infrastructure and ecosystems. Projections of mean global sea level (GSL) rise provide insufficient information to plan adaptive responses; local decisions require local projections that accommodate different risk tolerances and time frames and that can be linked to storm surge projections. Here we...

The problem of reconstructing a discrete set from its horizontal and vertical projections (RSP) is of primary importance in many different problems for example pattern recognition, image processing and data compression. We give a new algorithm which provides a reconstruction of convex polyominoes from horizontal and vertical projections. It costs atmost O(min(m, n) · mn log mn) for a matrix tha...

we study the problem of reconstructing binary images from four projections data in a fuzzy environment. given the uncertainly projections,w e want to find a binary image that respects as best as possible these projections. we provide an iterative algorithm based on fuzzy integer programming and linear membership functions.

1 Abstract Contact chemoreceptors (basiconic sensilla) located on the ovipositor and genital segments of the locust serve to control the chemical features of the substrate before and during oviposition. They occur dispersed and also crowded in fields between mechanosensory exteroceptors sensitive to touch or wind (trichoid and filiform sensilla). The central nervous projections of their four ch...

the problem of utilizing undesirable (bad) outputs in dea models often need replacing the assumption of free disposability of outputs by weak disposability of outputs. the kuosmanen technology is the only correct representation of the fully convex technology exhibiting weak disposability of bad and good outputs. also, there are some specific features of non-radial data envelopment analysis (dea...

The problem of utilizing undesirable (bad) outputs in DEA models often need replacing the assumption of free disposability of outputs by weak disposability of outputs. The Kuosmanen technology is the only correct representation of the fully convex technology exhibiting weak disposability of bad and good outputs. Also, there are some specific features of non-radial data envelopment analysis (DEA...