A method for sequence optimization in protein models is presented. The approach, which has inherited its basic philosophy from recent work by Deutsch and Kurosky @Phys. Rev. Lett. 76, 323 ~1996!# by maximizing conditional probabilities rather than minimizing energy functions, is based upon a different and very efficient multisequence Monte Carlo scheme. By construction, the method ensures that ...

We describe two Go programs, and , developed by a Monte-Carlo approach that is simpler than Bruegmann’s (1993) approach. Our method is based on Abramson (1990). We performed experiments to assess ideas on (1) progressive pruning, (2) all moves as first heuristic, (3) temperature, (4) simulated annealing, and (5) depth-two tree search within the Monte-Carlo framework. Progressive pruning and the...

RÉSUMÉ. Nous présentons YOPT, un programme qui joue au Hex en utilisant des techniques de Monte-Carlo. Nous décrivons des heuristiques pour améliorer les simulations et les descentes d’arbre Monte-Carlo. Nous abordons aussi l’utilisation d’heuristiques pour améliorer la parallélisation du programme. Le niveau de YOPT atteint le niveau de SIX pour les temps utilisés en compétition. ABSTRACT. We ...

background: because of the adverse effects of ionizing radiation on fetuses, prior to radiotherapy of pregnant patients, fetal dose should be estimated. fetal dose has been studied by several authors in different depths in phantoms with various abdomen thicknesses (at). in this study, the effect of maternal at and depth in fetal dosimetry was investigated, using peripheral dose (pd) distributio...

introduction: the key characteristics of positron emission tomography (pet) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. therefore, accurate quantification is important. however, it can be sensitive to several physical factors. the aim of this investigation is the assessment of the e...

conclusions according to the results, the old dosimetry formalisms, overestimate the dose especially towards the applicator’s tip. while the tg-43u1 based software perform the calculations more accurately. results for a typical arrangement of 10 active pellets in the applicator, the percentage difference between doses obtained by the new algorithm at 1cm distance from the tip of the applicator ...

large quantities of radiopharmaceuticals prescribed for treatment and diagnosis are excreted through kidney. therefore, radiation unwanted dose is created in kidney. as a result, exact calculation of prescribed radiopharmaceuticals amount is important. monte carlo method is used for simulation of radiation transport in body due to random nature of radiation. in this research, for the first time...

the interaction between the solute and the solsent molecules play a crucial role in understanding the various molecular processes involved in chemistry and biochemistry, so in this work the potential energy of active site of azurin have been calculated in solvent by the monte carlo simulation. in this paper we present quantitative results of monte carlo calculations of potential energies of ...

Simulating samples from arbitrary probability distributions is a major research program of statistical computing. Recent work has shown promise in an old idea, that sampling from a discrete distribution can be accomplished by perturbing and maximizing its mass function. Yet, it has not been clearly explained how this research project relates to more traditional ideas in the Monte Carlo literatu...

for superficial lesions, the electrons may be used for radiation therapy. the high energy photons and electrons are produced by a linear accelerator (linac).   many of electron fields need the shielding of normal or critical organs. the electron shields are usually lead slabs with few millimeter thickness which should be placed near the skin, less than 1 centimeter away from skin. in the inspec...