optimal designs
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Using numerical simulation, a search is carried out for designs of asymmetric barrier layers (ABLs) for a laser diode having GaAs waveguide and emitting at the wavelength λ = 980 nm. A pair of ABLs, adjoining the active region on both sides, blocks undesired charge carrier flows and suppresses parasitic spontaneous recombination in the waveguide layers. Optimal designs of ABLs based on AlGaAsSb and GaInP for blocking electrons and holes, respectively, are proposed that make it possible to reduce the parasitic recombination current down to less than 1% of the initial value. To suppress electron transport, an alternative structure based on three identical AlInAs barriers is also proposed. The GaAsP spacers separating these barriers from each other have different thicknesses. Due to this, its own set of quasi-bound (resonant) states is formed in each spacer that is different from the neighbor spacer set of states. As a result of this, the resonant tunneling channels are blocked: the parasitic electron flow is reduced by several tens of times in comparison with the case of spacers of equal thickness.

Various psychoactive substances that are in illegal circulation cause significant damage to the health of the population. Discussions among scientists about measures to reduce the level of drug use have not been stopped for many decades. The main goal of all researches is to search for effective anti-narcotic drugs and the implementation into practice of new technologies to counter drug crime. Following the scientists, a legislator tries to choose the most optimal designs that allow an objective and comprehensive assessment of the actions of violators, taking into account the need to save repressive measures. In the first edition, the current Criminal Code of the Russian Federation allowed the use of compulsory medical measures to persons with an established diagnosis of "drug addiction". Later, the measures of compulsory treatment were recognized as inhumane and abolished. They were replaced by the institution of imposing by the court on a drug addict the obligation to undergo treatment for drug addiction, medical and (or) social rehabilitation. As an interim measure, a legislator in 2013 put into effect Article 6.9.1 of the Code of Administrative Offences of the Russian Federation, which provides liability for evading a drug addict from the duty imposed by the court. Currently, a legislator offers to tighten the responsibility of a drug addict for evading treatment and rehabilitation by introducing an administrative prejudice. The conducted research has shown that it is possible to achieve the desired result by other means.

This study examines design preference in Completely Randomized (CR) split-plot experiments involving random whole plot factor effect and fixed sub-plot factor effect. Many previous works on optimally designing split-plot experiments assumed only factors with fixed levels. However, the cases where interests are on random factors have received little attention. These problems have similarities with optimal design of experiments for fixed parameters of non-linear models because the solution rely on the unknown parameters.  Design Space (DS) containing exhaustive list of balanced designs for a fixed sample size were compared for optimality using the product of determinants of derived information matrices of the Maximum Likelihood (ML) estimators equivalent to random and fixed effect in the model. Different magnitudes of components of variance configurations where variances of factor effects are larger than variances of error term were empirically used for the comparisons. The results revealed that the D-optimal designs are those with whole plot factor levels greater than replicates within each level of whole plot.

AbstractThe main intention of the present work is to outline the concept of equivariance and invariance in the design of experiments for generalized linear models and to demonstrate its usefulness. In contrast with linear models, pairs of transformations have to be employed for generalized linear models. These transformations act simultaneously on the experimental settings and on the location parameters in the linear component. Then, the concept of equivariance provides a tool to transfer locally optimal designs from one experimental region to another when the nominal values of the parameters are changed accordingly. The stronger concept of invariance requires a whole group of equivariant transformations. It can be used to characterize optimal designs which reflect the symmetries resulting from the group actions. The general concepts are illustrated by models with gamma distributed response and a canonical link. There, for a given transformation of the experimental settings, the transformation of the parameters is not unique and may be chosen to be nonlinear in order to fully exploit the model structure. In this case, we can derive invariant maximin efficient designs for the D- and the IMSE-criterion.