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The article describes the basic approaches of the calculation procedure of payload swim-out (objects of different function with own propulsor) from the underwater carrier a method of a self-exit using modern CFD technologies. It contains the description of swim-out by a self-exit method, its advantages and disadvantages. Also it contains results of research of convergence on a grid of a final-volume model with accuracy-time criterion, and results of comparison of calculation with experiment (validation of models). Validation of models was carried out using the available data of experimental definition of traction characteristics of water-jet propulsor of the natural sample in the development pool. Calculations of traction characteristics of water-jet propulsor were carried out via software package FlowVision ver. 3.10. On the basis of comparison of results of calculations for conditions of carrying out of experiments the error of water-jet propulsor calculated model which has made no more than 5% in a range of advance coefficient water-jet propulsor, realised in the process of swim-out by a selfexit method has been defined. The received value of an error of calculation of traction characteristics is used for definition of limiting settlement values of speed of branch of object from the carrier (the minimum and maximum values). The considered problem is significant from the scientific point of view thanks to features of the approach to modelling hydrojet moving system together with movement of separated object, and also from the practical point of view, thanks to possibility of reception with high degree of reliability of parametres swim-out of objects from sea bed vehicles a method of the self-exit which working conditions are assumed by movement in the closed volumes, already on a design stage.

A cluster method of mathematical modeling of interval-stochastic thermal processes in complex electronic systems (ES), is developed. In the cluster method, the construction of a complex ES is represented in the form of a thermal model, which is a system of clusters, each of which contains a core that combines the heat-generating elements falling into a given cluster, the cluster shell and a medium flow through the cluster. The state of the thermal process in each cluster and every moment of time is characterized by three interval-stochastic state variables, namely, the temperatures of the core, shell, and medium flow. The elements of each cluster, namely, the core, shell, and medium flow, are in thermal interaction between themselves and elements of neighboring clusters. In contrast to existing methods, the cluster method allows you to simulate thermal processes in complex ESs, taking into account the uneven distribution of temperature in the medium flow pumped into the ES, the conjugate nature of heat exchange between the medium flow in the ES, core and shells of clusters, and the intervalstochastic nature of thermal processes in the ES, caused by statistical technological variation in the manufacture and installation of electronic elements in ES and random fluctuations in the thermal parameters of the environment. The mathematical model describing the state of thermal processes in a cluster thermal model is a system of interval-stochastic matrix-block equations with matrix and vector blocks corresponding to the clusters of the thermal model. The solution to the interval-stochastic equations are statistical measures of the state variables of thermal processes in clusters - mathematical expectations, covariances between state variables and variance. The methodology for applying the cluster method is shown on the example of a real ES.

We describe an engineering-psychological experiment that continues the study of ways to adapt a person to the increasing complexity of logical problems by presenting a series of problems of increasing complexity, which is determined by the volume of initial data. Tasks require calculations in an associative or non-associative system of operations. By the nature of the change in the time of solving the problem, depending on the number of necessary operations, we can conclude that a purely sequential method of solving problems or connecting additional brain resources to the solution in parallel mode. In a previously published experimental work, a person in the process of solving an associative problem recognized color images with meaningful images. In the new study, a similar problem is solved for abstract monochrome geometric shapes. Analysis of the result showed that for the second case, the probability of the subject switching to a parallel method of processing visual information is significantly reduced. The research method is based on presenting a person with two types of tasks. One type of problem contains associative calculations and allows a parallel solution algorithm. Another type of problem is the control one, which contains problems in which calculations are not associative and parallel algorithms are ineffective. The task of recognizing and searching for a given object is associative. A parallel strategy significantly speeds up the solution with relatively small additional resources. As a control series of problems (to separate parallel work from the acceleration of a sequential algorithm), we use, as in the previous experiment, a non-associative comparison problem in cyclic arithmetic, presented in the visual form of the game “rock, paper, scissors”. In this problem, the parallel algorithm requires a large number of processors with a small efficiency coefficient. Therefore, the transition of a person to a parallel algorithm for solving this problem is almost impossible, and the acceleration of processing input information is possible only by increasing the speed. Comparing the dependence of the solution time on the volume of source data for two types of problems allows us to identify four types of strategies for adapting to the increasing complexity of the problem: uniform sequential, accelerated sequential, parallel computing (where possible), or undefined (for this method) strategy. The Reducing of the number of subjects, who switch to a parallel strategy when encoding input information with formal images, shows the effectiveness of codes that cause subject associations. They increase the speed of human perception and processing of information. The article contains a preliminary mathematical model that explains this phenomenon. It is based on the appearance of a second set of initial data, which occurs in a person as a result of recognizing the depicted objects.

The utilization of unmanned aerial vehicles (UAVs) in high-rise firefighting operations is the right solution for reaching the fire scene on high floors quickly and effectively. The article proposes a quadrotor-type firefighting UAV model carrying a launcher to launch a missile containing fire extinguishing powders into a fire. The kinematic model describing the flight kinematics of this UAV model is built based on the Newton – Euler method when the device is in normal motion and at the time of launching a firefighting missile. The results from the simulation testing the validity of the kinematic model and the simulation of the motion of the UAV show that the variation of Euler angles, flight angles, and aerodynamic angles during a flight are within an acceptable range and overload guarantee in flight. The UAV flew to the correct position to launch the required fire-extinguishing ammunition. The results of the research are the basis for building a control system of high-rise firefighting drones in Vietnam.

Actin is a conserved structural protein that is expressed in all eukaryotic cells. When polymerized, it forms long filaments of fibrillar actin, or F-actin, which are involved in the formation of the cytoskeleton, in muscle contraction and its regulation, and in many other processes. The dynamic and mechanical properties of actin are important for interaction with other proteins and the realization of its numerous functions in the cell. We performed 204.8 ns long molecular dynamics (MD) simulations of an actin filament segment consisting of 24 monomers in the absence and the presence of MgADP at 300 K in the presence of a solvent and at physiological ionic strength using the AMBER99SBILDN and CHARMM36 force fields in the GROMACS software environment, using modern structural models as the initial structure obtained by high-resolution cryoelectron microscopy. MD calculations have shown that the stationary regime of fluctuations in the structure of the F-actin long segment is developed 80–100 ns after the start of the MD trajectory. Based on the results of MD calculations, the main parameters of the actin helix and its bending, longitudinal, and torsional stiffness were estimated using a section of the calculation model that is far enough away from its ends. The estimated subunit axial (2.72–2.75 nm) and angular (165–168^◦) translation of the F-actin helix, its bending (2.8–4.7 · 10⁻²⁶ N·m²), longitudinal (36–47·10⁻⁹ N), and torsional (2.6–3.1·10⁻²⁶ N·m²) stiffness are in good agreement with the results of the most reliable experiments. The results of MD calculations have shown that modern structural models of F-actin make it possible to accurately describe its dynamics and mechanical properties, provided that computational models contain a sufficiently large number of monomers, modern force fields, and relatively long MD trajectories are used. The inclusion of actin partner proteins, in particular, tropomyosin and troponin, in the MD model can help to understand the molecular mechanisms of such important processes as the regulation of muscle contraction.

As the population of cities grows, the need to plan for the development of transport infrastructure becomes more acute. For this purpose, transport modeling packages are created. These packages usually contain a set of convex optimization problems, the iterative solution of which leads to the desired equilibrium distribution of flows along the paths. One of the directions for the development of transport modeling is the construction of more accurate generalized models that take into account different types of passengers, their travel purposes, as well as the specifics of personal and public modes of transport that agents can use. Another important direction of transport models development is to improve the efficiency of the calculations performed. Since, due to the large dimension of modern transport networks, the search for a numerical solution to the problem of equilibrium distribution of flows along the paths is quite expensive. The iterative nature of the entire solution process only makes this worse. One of the approaches leading to a reduction in the number of calculations performed is the construction of consistent models that allow to combine the blocks of a 4-stage model into a single optimization problem. This makes it possible to eliminate the iterative running of blocks, moving from solving a separate optimization problem at each stage to some general problem. Early work has proven that such approaches provide equivalent solutions. However, it is worth considering the validity and interpretability of these methods. The purpose of this article is to substantiate a single problem, that combines both the calculation of the trip matrix and the modal choice, for the generalized case when there are different layers of demand, types of agents and classes of vehicles in the transport network. The article provides possible interpretations for the gauge parameters used in the problem, as well as for the dual factors associated with the balance constraints. The authors of the article also show the possibility of combining the considered problem with a block for determining network load into a single optimization problem.

New numerical simulation technique to calculate electrical properties of rocks with two-phase “oil– water” saturation is proposed. This technique takes into account surface conductivity of electrical double layers at the contact between solid rock and aqueous solution inside pore space. The numerical simulation technique is based on acquiring of electrical potential distribution in high-resolution three-dimensional digital model of porous medium. The digital model incorporates the spatial geometry of pore channels and contains bulk and surface grid cells. Numerical simulation results demonstrate the importance of surface conductivity effects.

This paper formulates and solves a practical problem of data recovery regarding the distribution of languages on regional level in context of China. The necessity of this recovery is related to the problem of the determination of the linguistic diversity indices, which, in turn, are used to analyze empirically and to predict sources of social and economic development as well as to indicate potential conflicts at regional level. We use Ethnologue database and China census as the initial data sources. For every language spoken in China, the data contains (a) an estimate of China residents who claim this language to be their mother tongue, and (b) indicators of the presence of such residents in China provinces. For each pair language/province, we aim to estimate the number of the province inhabitants that claim the language to be their mother tongue. This base problem is reduced to solving an undetermined system of algebraic equations. Given additional restriction that Ethnologue database introduces data collected at different time moments because of gaps in Ethnologue language surveys and accompanying data collection expenses, we relate those data to a single time moment, that turns the initial task to an ’ill-posed’ system of algebraic equations with imprecisely determined right hand side. Therefore, we are looking for an approximate solution characterized by a minimal discrepancy of the system. Since some languages are much less distributed than the others, we minimize the weighted discrepancy, introducing weights that are inverse to the right hand side elements of the equations. This definition of discrepancy allows to recover the required variables. More than 92% of the recovered variables are robust to probabilistic modelling procedure for potential errors in initial data.

The paper contains numerical simulation of nonisothermal nonlinear flow in a porous medium. Twodimensional unsteady problem of heavy oil, water and steam flow is considered. Oil phase consists of two pseudocomponents: light and heavy fractions, which like the water component, can vaporize. Oil exhibits viscoplastic rheology, its filtration does not obey Darcy's classical linear law. Simulation considers not only the dependence of fluids density and viscosity on temperature, but also improvement of oil rheological properties with temperature increasing.

To solve this problem numerically we use streamline method with splitting by physical processes, which consists in separating the convective heat transfer directed along filtration from thermal conductivity and gravitation. The article proposes a new approach to streamline methods application, which allows correctly simulate nonlinear flow problems with temperature-dependent rheology. The core of this algorithm is to consider the integration process as a set of quasi-equilibrium states that are results of solving system on a global grid. Between these states system solved on a streamline grid. Usage of the streamline method allows not only to accelerate calculations, but also to obtain a physically reliable solution, since integration takes place on a grid that coincides with the fluid flow direction.

In addition to the streamline method, the paper presents an algorithm for nonsmooth coefficients accounting, which arise during simulation of viscoplastic oil flow. Applying this algorithm allows keeping sufficiently large time steps and does not change the physical structure of the solution.

Obtained results are compared with known analytical solutions, as well as with the results of commercial package simulation. The analysis of convergence tests on the number of streamlines, as well as on different streamlines grids, justifies the applicability of the proposed algorithm. In addition, the reduction of calculation time in comparison with traditional methods demonstrates practical significance of the approach.

The work continues research on the ability of a person to improve the productivity of information processing, using parallel work or improving the performance of analyzers. A person receives a series of tasks, the solution of which requires the processing of a certain amount of information. The time and the validity of the decision are recorded. The dependence of the average solution time on the amount of information in the problem is determined by correctly solved problems. In accordance with the proposed method, the problems contain calculations of expressions in two algebras, one of which is associative and the other is nonassociative. To facilitate the work of the subjects in the experiment were used figurative graphic images of elements of algebra. Non-associative calculations were implemented in the form of the game “rock-paper-scissors”. It was necessary to determine the winning symbol in the long line of these figures, considering that they appear sequentially from left to right and play with the previous winner symbol. Associative calculations were based on the recognition of drawings from a finite set of simple images. It was necessary to determine which figure from this set in the line is not enough, or to state that all the pictures are present. In each problem there was no more than one picture. Computation in associative algebra allows the parallel counting, and in the absence of associativity only sequential computations are possible. Therefore, the analysis of the time for solving a series of problems reveals a consistent uniform, sequential accelerated and parallel computing strategy. In the experiments it was found that all subjects used a uniform sequential strategy to solve non-associative problems. For the associative task, all subjects used parallel computing, and some have used parallel computing acceleration of the growth of complexity of the task. A small part of the subjects with a high complexity, judging by the evolution of the solution time, supplemented the parallel account with a sequential stage of calculations (possibly to control the solution). We develop a special method for assessing the rate of processing of input information by a person. It allowed us to estimate the level of parallelism of the calculation in the associative task. Parallelism of level from two to three was registered. The characteristic speed of information processing in the sequential case (about one and a half characters per second) is twice less than the typical speed of human image recognition. Apparently the difference in processing time actually spent on the calculation process. For an associative problem in the case of a minimum amount of information, the solution time is near to the non-associativity case or less than twice. This is probably due to the fact that for a small number of characters recognition almost exhausts the calculations for the used non-associative problem.