Creation of a Supercomputer Simulation of a Society with Different Types of Active Agents and Its Approbation.

This article continues a series of works devoted to the creation of large agent-based models, built as an artificial society, and the development of software for their implementation-the MÖBIUS design system for scalable agent-based models. The basic core of the system is a demographic model that simulates the natural movement of the population. A new stage in the development of the work discussed in this article was the creation on the basis of this core of an agent-based model of Russia, which includes families as agents of a new type, hierarchically connected with human agents. In addition, objects of a new type were introduced into the model-projects that provide for the creation in an artificial environment of analogues of complex control actions aimed at stimulating fertility. Developed on the basis of simulating the reaction of individual families to the introduced regional support measures, the model makes it possible to track their impact on key demographic indicators. The agent-based model of Russia was tested on data for a long retrospective period using the example of the launch of maternal capital programs and showed good agreement with official statistics.

Reconciling simulated melting and ground-state properties of metals with a modified embedded-atom method potential.

We propose a modification of the embedded-atom method-type potential aiming at reconciling simulated melting and ground-state properties of metals by means of classical molecular dynamics. Considering titanium, magnesium, gold, and platinum as case studies, we demonstrate that simulations performed with the modified force field yield quantitatively correctly both the melting temperature of the metals and their ground-state properties. It is shown that the accounting for the long-range interatomic interactions noticeably affects the melting point assessment. The introduced modification weakens the interaction at interatomic distances exceeding the equilibrium one by a characteristic vibration amplitude defined by the Lindemann criterion, thus allowing for the correct simulation of melting, while keeping its behavior in the vicinity of the ground state minimum. The modification of the many-body potential has a general nature and can be applicable to metals with different characteristics of the electron structure as well as for many different molecular and solid state systems experiencing phase transitions.