To the evolution model of network graph structure construction

In this paper the investigation of the structure of network graph is presented. The social network between the Russian towns is considered. It is shown, that the distribution of vertex powers is uniform. As a consequence there is a high dimension region with whole connection. The probability of special sub-graphs is estimated. The Liouville equation is used for modeling of the graph structure evolution.

Construction of a model of evolution of objects of small-sized fraction of space debris formed as a result of destruction

The paper proposes a approach for constructing a statistical model for the distribution of a small-sized fraction of space debris in near-earth space, based on a particular model of the evolution of objects of a small-sized fraction of space debris. An algorithm for predicting the evolution of objects of small-sized fraction of space debris formed as a result of the destruction of the parent space object over a long time interval is described, as well as a system of equations in variations for mass calculations and statistical estimates of the parameters of the distribution of space debris in near-earth space. At a time interval of 10 years, calculations were carried out to obtain a common understanding of the evolution and lifetime of fragments of space debris ranging in size from 0.01 to 1 mm in the orbits of real groups and individual spacecraft. The time of existence of objects of small-sized fraction of space debris of the specified sizes depending on the parameters of the orbit and the value of their area-to-mass ratio is determined.

Investigation of the properties of a quasi-gas-dynamic system of equations based on the solution of the Riemann problem for a mixture of gases

The accuracy and stability of an explicit numerical algorithm for modeling the flows of a mixture of compressible gases in the transonic regime are investigated by the example of solving the Riemann problem on the decay of a gas-dynamic discontinuity between different gases. The algorithm is constructed using the finite volume method based on the regularized gas dynamics equations for a mixture of gases. A method for suppressing nonphysical oscillations occurring behind the contact discontinuity is found.

Combined recommender algorithms for enterprises

The authors describe an approach to the implementation of combined algorithms for recommender systems considered with the example of a separate module of the information system of an enterprise. We propose four groups of criteria, which, using various approaches, allows one to explore and evaluate objects in relation to the problem of developing recommendations. During a research database schema required for the implementation of the algorithm has been developed, as well as the software.

Gravitational instability and the formation of planetary systems of solar-type stars

The fundamental principles of the protoplanetary ring model – the model of formation of planetary systems of stars, which is based on the origin and development of large-scale gravitational instabilities (protoplanetary rings) – are extended to the formation of regular planetary satellites. Based on these principles, a complete model of the formation of planetary systems, including their satellites, (model of gas and dust rings) for solar-type stars is proposed.

On the use of a cell-centered finite-volume scheme on prismatic meshes in boundary layers

We consider the cell-centered finite-volume scheme with the quasi-one-dimensional reconstruction and generalize it to anisotropic prismatic meshes suitable for high-Reynolds-number problems. We offer a new algorithm of flux computation based on the reconstruction along the wall surface, whereas in the original schemes it was along the tangent to the wall surface. We also study how does the curvature of mesh elements influence the accuracy if taken into account.

Review of space vehicle control and guidance methods at atmosphere reentry

Review of control methods for statically stable reentry vehicles with low lift-to-drag ratio at returning from the Moon is presented. We are considering algorithms that have been used in Soviet and American Moon programs, as well as advanced algorithms that now are developed. General trends of advanced domestic and foreign methods are determined.

On self-correcting logic circuits of unreliable gates

The following statements are proved: 1) for any integer m ≥ 3 there is a basis consisting of Boolean functions of no more than m variables, in which any Boolean function can be implemented by a logic circuit of unreliable gates that self-corrects relative to certain faults in an arbitrary number of gates; 2) for any positive integer k there are bases consisting of Boolean functions of no more than two variables, in each of which any Boolean function can be implemented by a logic circuit of unreliable gates that self-correct relative to certain faults in no more than k gates; 3) there is a functionally complete basis consisting of Boolean functions of no more than two variables, in which almost no Boolean function can be implemented by a logic circuit of unreliable gates that self-correct relative to at least some faults in no more than one gate.

Comparative analysis of the geometrized histogram method and the neural network method for road markings recognition

This paper compares two approaches to determining road markings from video sequences, namely, the method of finding the markings using geometrized histograms and the method based on neural networks. An independent open dataset TuSimple is used to conduct a comparative analysis of the algorithms. Since the investigated methods have different architectures, their work is evaluated according to the following metrics: Accuracy, speed (relative FPS), general computational complexity of the algorithm (TFlops).