Search of the optimal strategy for refinement of atomic models
نویسندگان
چکیده
Recently it has been shown (Afonine et al, 2001; Lunin et al., 2002) that the approximation of the maximum likelihood criterion (ML) by a quadratic functional (Lunin & Urzhumtsev, 1999) allows to understand the features of the ML refinement and its advantages with respect to the traditional least-squares (LS) refinement. In this latter, the magnitudes { } S calc F ∈ s s of structure factors calculated from the current atomic model are fitted to the observed structure factor magnitudes { } S obs F ∈ s s by minimisation of ( ) ∑ ∈ − =
منابع مشابه
A GUIDED TABU SEARCH FOR PROFILE OPTIMIZATION OF FINITE ELEMENT MODELS
In this paper a Guided Tabu Search (GTS) is utilized for optimal nodal ordering of finite element models (FEMs) leading to small profile for the stiffness matrices of the models. The search strategy is accelerated and a graph-theoretical approach is used as guidance. The method is evaluated by minimization of graph matrices pattern equivalent to stiffness matrices of finite element models. Comp...
متن کاملA Differential Evolution and Spatial Distribution based Local Search for Training Fuzzy Wavelet Neural Network
Abstract Many parameter-tuning algorithms have been proposed for training Fuzzy Wavelet Neural Networks (FWNNs). Absence of appropriate structure, convergence to local optima and low speed in learning algorithms are deficiencies of FWNNs in previous studies. In this paper, a Memetic Algorithm (MA) is introduced to train FWNN for addressing aforementioned learning lacks. Differential Evolution...
متن کاملNew Provider Models for Sweden and Spain: Public, Private or Non-profit?; Comment on “Governance, Government, and the Search for New Provider Models”
Sweden and Spain experiment with different provider models to reform healthcare provision. Both models have in common that they extend the role of the for-profit sector in healthcare. As the analysis of Saltman and Duran demonstrates, privatisation is an ambiguous and contested strategy that is used for quite different purposes. In our comment, we emphasize that their analysis leaves questions ...
متن کاملA Monte Carlo-Based Search Strategy for Dimensionality Reduction in Performance Tuning Parameters
Redundant and irrelevant features in high dimensional data increase the complexity in underlying mathematical models. It is necessary to conduct pre-processing steps that search for the most relevant features in order to reduce the dimensionality of the data. This study made use of a meta-heuristic search approach which uses lightweight random simulations to balance between the exploitation of ...
متن کاملDetermining the Optimal Strategy of Multi Virtual Power Plants using GA-GT
abstract: In the present work, determining the optimal strategy(profit based) of multi virtual power plants (VPPs) as well as the objective of maximizing profit through the multi-level control of VPPs are discussed by the micro-grid utilization center including virtual power plants. VPPs include renewable resources such as wind farms, photovoltaic, and conventional resources such as fuel cell, ...
متن کامل