A method for ab initio structure factor retrieval from large-angle rocking-beam electron diffraction data of thin crystals is described and tested with experimental and simulated data. No additional information, such as atomicity or information about chemical composition, has been made use of. Our numerical experiments show that the inversion of dynamical scattering works best, if the beam tilt...

We test the effectiveness of the multicanonical algorithm for the tertiary structure prediction of peptides and proteins. As a simple example we study Metenkephalin. The lowest-energy conformation obtained agrees with that determined by other methods such as Monte Carlo simulated annealing. But unlike to simulated annealing the relationship to the canonical ensemble remains exactly controlled. ...

It has been known that in anomaly-mediated SUSY breaking model Affleck-Dine baryogenesis does not work due to trapping of Affleck-Dine field into charge-breaking minima. We show that when finite-temperature effect is properly taken into account and if reheating temperature is relatively high, the problem of falling into charge breaking global minima can be avoided and hence Affleck-Dine baryoge...

The aim of this paper is to investigate from the numerical point of view the coupling of the Hamilton-Jacobi-Bellman (HJB) equation and the Pontryagin minimum principle (PMP) to solve some control problems. A rough approximation of the value function computed by the HJB method is used to obtain an initial guess for the PMP method. The advantage of our approach over other initialization techniqu...

The global minima of clusters bound by a Dzugutov potential form non-compact polytetrahedral clusters mainly composed of interpenetrating and face-sharing 13-atom icosahedra. As the size increases, these icosahedral units first form linear arrays, then two-dimensional rings, then three-dimensional networks. Characterization of the energy landscapes of these clusters shows that they are particul...

We apply the method known as simulated annealing to the following problem in convex optimization: minimize a linear function over an arbitrary convex set, where the convex set is specified only by a membership oracle. Using distributions from the Boltzmann-Gibbs family leads to an algorithm that needs only O∗( √ n) phases for instances in R. This gives an optimization algorithm that makes O∗(n4...

Deterministic global optimization plays an essential role in the solution of many diicult problems with applications ranging from economics and operations research to computational chemistry and molecular biology. In this chapter we explore the application of deterministic global optimization approaches to problems related to protein structure prediction. Due to the complex nature of protein in...

Model complexity in neural-network learning is investigated using tools from nonlinear approximation and integration theory. Estimates of network complexity are obtained from inspection of upper bounds on convergence of minima of error functionals over networks with an increasing number of units to their global minima. The estimates are derived using integral transforms induced by computational...

For the saturated carbonyl trimer Ru(3)(CO)(12) theoretical methods predict a doubly bridged Ru(3)(CO)(10)(mu-CO)(2) structure to lie only 0.3 kcal mol(-1) above the unbridged global minimum in accord with the fluxional properties observed experimentally by carbon-13 NMR on the very stable unbridged Ru(3)(CO)(12). For M(3)(CO)(11) and M(3)(CO)(10) the global minima for the Fe, Ru, and Os deriva...