Published in Entropy
The approximated nonlinear least squares (ALS) method has been used for the estimation of unknown parameters in the complex computer code which is very time-consuming to execute. The ALS calibrates or tunes the computer code by minimizing the squared difference between real observations and computer output using a surrogate such as a Gaussian proce...
In this paper we consider two nested computer codes, with the first code output as one of the second code inputs. A predictor of this nested code is obtained by coupling the Gaussian predictors of the two codes. This predictor is non Gaussian and computing its statistical moments can be cumbersome. Sequential designs aiming at improving the accurac...
In the context of sensitivity analysis of complex phenomena in presence of uncertainty, we motivate and precise the idea of orienting the analysis towards a critical domain of the studied phenomenon. For this, target and conditional sensitivity analyses are defined.We make a brief history of related approaches in the literature, and propose a more ...
The Eulerian recurrent length of a graph G, e(G), is the maximum of the shortest subcycle length of Eulerian circuits of G. Upper and lower bounds on the Eulerian recurrent length of complete graphs was provided by the author as n-4leqq e(K_{n})leqq n-3 for odd integers ngeqq 15. In this article, the method of proving the inequality is improved.
A few properties of minimax and maximin optimal designs in a compact subset of R^d are presented, and connections with other space-filling constructions are indicated. Several methods are given for the evaluation of the minimax-distance (or dispersion) criterion for a given n-point design. Various optimisation methods are proposed and their limitat...
We consider the problem of constructing metamodels for computationally expensive simulation codes; that is, we construct interpolation/prediction of functions values (responses) from a finite collection of evaluations (observations). We use Gaussian process modeling and Kriging, and combine a Bayesian approach, based on a finite set of covariance f...
Published in Archives of Control Sciences
In many applications in sequencing and scheduling it is desirable to have an underlaying graph as equitably colored as possible. In this paper we survey recent theoretical results concerning conditions for equitable colorability of some graphs and recent theoretical results concerning the complexity of equitable coloring problem. Next, since the ge...
Published in Steel in Translation
To determine the best heat treatment of steel, thermokinetic diagrams of austenite decomposition are required. Experimental determination of those diagrams is extremely difficult. In the present work, a model of the phase transitions is proposed; the model takes account of the structure of powder steel. A method is developed for computer experiment...
Computer assisted optimal illumination design is crucial when developing cost-effective machine vision systems. Standard local optimization methods, such as downhill simplex optimization (DHSO), often result in an optimal solution that is influenced by the starting point by converging to a local minimum, especially when dealing with high dimensiona...
Published in Russian Journal of Genetics: Applied Research
A mathematical model is constructed which describes the impacts of a chaotically changing environment on the frequencies and productivity of partners in the legume-rhizobia symbiosis (LRS). The most sensitive for external impacts are the adaptively prospective bacteria strains which are specific with respect to hosts and are capable for the intensi...
