Crossover designs are efficient alternatives to parallel designs. Sample size reduction, comparing the 2x2 crossover to a two-arm parallel study, is approximately 4 to 1 in diabetes clinical trials. One challenge of using a crossover design is understanding and handling potential carryover effects. This paper will review the fundamentals of the crossover design, including design, model, and ana...

Differential evolution (DE) is a powerful algorithm to find an optimal solution in real world problems. Nevertheless, the binomial crossover parameter is an important issue for the success of the algorithm. The proper selection of the binomial crossover parameter depends on the problem at hand. In this work, the effect of the binomial crossover in the DE/Rand/1/bin, DE/Best/1/Bin and DE/Current...

Geometric crossover is a representation-independent generalization of the traditional crossover defined using the distance of the solution space. By choosing a distance firmly rooted in the syntax of the solution representation as a basis for geometric crossover, one can design new crossovers for any representation. Using a distance tailored to the problem at hand, the formal definition of geom...

despite the role of oral corticosteroids in management of sever asthma, use of these drugs needs careful awareness of its many side effects. there are controversies about the role of methotrexate in lowering the need for corticosteroides in these patients. in this study an attempt has been made to determine methotrexate effects in corticosteroid dependent asthma. six patients were entered in a ...

Several recombination operators have been proposed in evolutionary computation. Standard procedures include one-point, two-point, and uniform crossover. Little attention, however, has been given to a recombination operator that preceded each of these, which was offered in 1957 by Alex Fraser. Fraser’s recombination assigns a variable probability for crossing over between two solutions at each l...

In its recent guidance on bioequivalence, the U.S. Food and Drug Administration (FDA) recommends a two-sequence, four-period (2 x 4) replicated crossover design be used for assessment of population and individual bioequivalence [FDA. Guidance for Industry on Statistical Approaches to Establishing Bioequivalence; Center for Drug Evaluation and Research, Food and Drug Administration: Rockville, M...

In recent years, the number of studies using a cluster-randomized design has grown dramatically. In addition, the cluster-randomized crossover design has been touted as a methodological advance that can increase efficiency of cluster-randomized studies in certain situations. While the cluster-randomized crossover trial has become a popular tool, standards of design, analysis, reporting and impl...

Crossover designs are well-known to have major advantages when comparing the effects of various non-curative treatments. We compare efficiencies of several crossover designs along with the Balaam’s design with that of a parallel group design pertaining to longitudinal studies where event time can only be measured in discrete time intervals. With equally sized sequences, the parallel group desig...