Informatica

The paper deals with the analysis of the two survival models of the accelerated failure‐time using two‐parametrical log‐logistic and Weibull distributions, and survival models using conditional generalized Weibull, log‐logistic, and Smith and Bain distributions. The observed survival (number of deaths during the 30‐year follow‐up period among the study cohort) and the survival predicted by regression models (predicted number of deaths for the same period of time) were compared. Data on deaths occurring in random sample of men were obtained from the death register of the city of Kaunas. The best agreement between the predicted and observed survival was obtained with one of the modified Smith and Bain models.

The paper analyzes the performance of parallel global optimization algorithm, which is used to optimize grillage-type foundations. The parallel algorithm is obtained by using the automatic parallelization tool. We describe briefly the layer structure of the Master–Slave Template library and present a detailed mathematical formulation of the application problem. Experiments are done on the homogeneous computer cluster of 7 IBM machines RS6000. The results of experiments are presented.

This article is an introduction to the simplest mathematical model, which describes the hormone interaction during the menstrual cycle. Modifications of the mathematical model of the menstrual cycle including the mathematical model with the time delay depending on function researched and the mathematical model with the dispersed time delay are researched and described here. A numerical investigation was conducted, during which solutions for the above mentioned models were calculated. The solutions found are compared mutually and with the clinical data.

A system of two nonlinear difference-differential equations which is a mathematical model of self-regulation of glucose level in blood with time delay into consideration of insulin “age structure” is presented. The analysis carried out by qualitative and numerical methods allows us to conclude, that the mathematical model explains the functioning of the physiological system “insulin-blood glucose” in normal and pathological cases.