Introduction: Quantitative evaluation is recommended to improve diagnostic ability and serial assessment of dopamine transporter (DAT) density scans. We decided to compare the ordered subsets expectation-maximization (OSEM) with filtered back-projection (FBP), and to investigate the impact of different iteration and cut-off frequencies on SBR values. Methods</stro...

We address the problem of learning good policies in poker games. The classical game theoretic approach to this problem specifies a Nash equilibrium solution, i.e., a pair of secure mixed (randomized) policies. We describe a new approach for calculating such secure policies based on coevolution. Here, populations of pure policies for both players are simultaneously evolved by repeated comparison...

AbstTactA state-dependent policy for call admission and routing in a multi-service circuit-switched network is synthesiced. To meet different requirements the objective function is defined as the mean value of reward from the network. Policy iteration is applied to find the optimal control. Assuming link independence the network reward process is decomposed into the set of link reward processes...

Asynchronous iterations arise naturally on parallel computers if one wants to minimize idle times. This paper reviews certain models of asynchronous iterations, using a common theoretical framework. The corresponding convergence theory and various domains of applications are presented. These include nonsingular linear systems, nonlinear systems, and initial value problems. c © 2000 Elsevier Sci...

Recall that a vector norm on R is a mapping ‖·‖ : R → R satisfying the following conditions: • ‖x‖ > 0 for x 6= 0. • ‖λx‖ = |λ|‖x‖ for x ∈ R and λ ∈ R. • ‖x+ y‖ ≤ ‖x‖+ ‖y‖ for all x, y ∈ R. Since the space Rn×n of all matrices is also a vector space, it is also possible to consider norms there. In contrast to usual vectors, it is, however, also possible to multiply matrices (that is, the matric...