Modelling strategies for value-added multilevel models are examined. These types of models typically include an endogenous variable and this causes difficulties for the standard estimation techniques that are commonly used to analyse multilevel models. Two alternative estimation strategies are proposed: one using an instrumental variable approach and the other using a Bayesian analysis as avail...

Introduction: Brain tumorr is a deadly disease but patients can have positive growth psychologically. It is important to find factors that lead psychological growth of patients. Therefore, this study was aimed to predict the post traumatic growth based on social support, coping styles and optimism in patients with brain tumor. Methods: In this correlational and descriptive study, the statistic...

A set of ordered rules for generating variants of a variable determines (a) underlying/surface distinctions among some of the variants and (b) a hierarchical classification of the variants. In the analytical framework of variable rules, frequency data on variant occurrences in context bear only on (b) and not on (a). We provide a combinatorial characterization and enumeration of the set of clas...

The traditional variable selection problem has attracted renewed attention from statistical researchers due to the recent advances in data collection, especially in fields such as bioinformatics and marketing. In this paper, we formulate regression variable selection as an optimization problem, propose and study several deterministic and stochastic sequential optimization methods with lookahead...

State of the art methods for state estimation and perception make use of least-squares optimization methods to perform efficient inference on noisy sensor data. Much of this efficiency is achieved by using sparse matrix factorization methods. The sparsity structure of the underlying matrix factorization which makes these optimization methods tractable is highly dependent on the choice of variab...

Objective: To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Methods: Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "...

We analyze five parallelization strategies for the Variable Neighborhood Search (VNS) meta-heuristic. They are based on asynchronous cooperation of several search threads. We tested parallelization on various levels, from a low-level parallel neighborhood exploration, through medium-grained asynchronous execution of basic VNS steps (shaking and local search), to the coarse-grained asynchronous ...