This article refers to labor costs estimation of information system functional requirements design problem in a service-oriented architecture. Stochastic model of information system services identification process is offered for this purpose, which allows providing the estimation of expected project objects and interrelations amount using minimal initial data. This model is based on automated business-process decomposition representation as a branching random supercritical Galton-Watson process. Decomposition elements relation design is been modeled as connected random graph construction process by Erdosh-Renyi model. Model predictions have been confirmed through verification by experimental data.

In article questions of an evaluation of complexity of large-block cloud computing with enhanced accuracy are considered. This development is directed on the decision in a cloud of tasks of mathematical simulation with special requirements of accuracy. In particular it is about obtaining the precision and confidential solution of tasks with complex couplings between subtasks in the form of large blocks and the score time considerably exceeding transmission time of information in between. The methodology of an evaluation of complexity of tasks of this sort used for creation of the computing systems, optimum on productivity functioning in the cloudy environment is offered.

The paper discusses the issues related to ensuring the effective scaling of the job flow generated by problem-oriented distributed computing systems in heterogeneous Grid with hybrid nodes. Considers the multiagent methods and tools of the new generation, to ensure effective management of the combined job flow of scalable service-oriented software systems and load balancing for computing resources of runtime environment. Describes a high-level tools for developing services of scalable software systems. A distinctive feature of the presented methods and tools is use of elements of the economic theory (such as elements of regulation of supply and demand of resources) in the coordinated multiagent management of cluster Grid with hybrid nodes, both at the Grid level, and at the application level. The functions of problem-oriented computing environment (user application) is realized in the form of Grid-services using technology Web Services Resource Framework and patterns of interaction with local resource managers of Grid nodes. To create the agent of application is used development environment High-performance computing Service-oriented Multiagent System Framework, developed by the authors. A number of scientific services for experimental Grid are given as examples of organization of the problem-oriented computing environment (user application) using methods and tools considered in this paper. The results of their effective functioning is analyzed.

This paper is devoted to known plaintexts cryptanalysis of homomorphic cryptosystem proposed by Domingo-Ferrer. In previous works it was shown that at least pairs (plaintext, ciphertext) are necessary to recover secret key, where is a degree of polynomials representing ciphertexts. Here we analyze existing known plaintext attack. And also slightly modified attack on this cryptosystem is presented. It allows to reduce the necessary number of pairs meaningfully. In particular interception only of two pairs may be enough for successful key recovering with overwhelming probability. The running time of our attack depends polynomially on and logarithmically on plaintexts space size as well as for previous attack. We provide the results of computer experiments.

Fully homomorphic encryption (FHE) is a recognized tool to obtain the cryptographic protec-tion of cloud computing. However, the characteristics of existing FHE schemes are not suffi-cient for use in practice � the security of some FHE is unsatisfying, others require too much computational resources. For improvement the efficiency of the last one IBM researchers pro-posed a method for "ciphertexts batching", which was applied by them to public key FHE scheme whose security is based on the complexity of the lattice theory hardness assumptions. In this paper, we discuss several methods for embedding "ciphertexts batching" into recently proposed symmetric encryption scheme based on matrix polynomials. For one of this method we completely specify how cryptosystem algorithms should work. The results of computer experiments are given.

Direct numerical simulation of internal gravity waves focusing and developement of a wave attractor was performed with the help of two different numerical approaches. Mathematical formulation corresponds to experiments on exitations of inner waves in a trapezoidal container with salt solutions through forced oscillations of the left boundary. It was shown that numerical simulations reproduce the experiments after taking into account ther imperfection of linear salinity profile near the upper boundary. The amplitudes of resulting oscillations in both numerical simulations are increased as compared to the experiments due to loss of energy of the 3D wave generator in the experiments. Despite the fact that the general shape of the attractor is reproduced by both method, there are differences in velocity profiles near the left boundary. This fact requires further investigations since this discrepancy may in influence nonlinear dynamics of developing instabilities.

Vibrofluidization is widely used in various industrial processes. So the study of vibrofluidization modes is current research. In this paper we investigated the modes of vibrofluidized layer using the package OpenFOAM. The results of modelling of the vibrofluidized layer dynamics at different values of the amplitude and frequency of oscillations, the thickness of the filling, were presented. The modes in which layer becomes unstable were identified. Wavelets formed from granular material and the jetting channels appear in these modes

OpenFOAM is a proven engineering tool for applied hydrodynamics numerical modeling which is typically characterized by complex geometries and large grids of 107-108 cells. Since such calculations are often very long and resource-intesive, any way of speeding them up is of high practical interest. Based on one practical problem of a screw propeller characteristics modeling, optimizations to OpenFOAM via the originally developed SLAE solution plugin is proposed. The plugin is based on SparseLinSol (SLS) library, developed by the authors. The library uses Krylov subspace iterative methods with the Classic AMG preconditioner to effectively solve large SLAEs on supercomputers and features original hybrid communications model which implements MPI and Posix Shared Memory combination. The library also is able to utilize NVIDIA GPU accelerators for a significant part of the implemented algorithms. Test results on 128-node computational system equipped with NVIDIA X2070 accelerators show that: (i) OpenFOAM numerical modeling results are close to those achieved with Star-CCM package and experimental results; (ii) developed SLAE solution methods are more robust than those implemented in original OpenFOAM GAMG-based SLAE solver; (iii) hybrid communication model improves solver scalability a lot and the solver scales linearly up to the maximum number of nodes used in current tests; (iv) GPU usage makes calculations 1.4-3 times faster; (v) SLS solver is faster than hypre solver on the same set of implemented methods and test matrices

It is proposed to modify the Godunov computation method for modeling the gas-liquid bubble flow. To have a numerical scheme, effect of the coefficients - at the differential constituents in the hydrodynamic averaged equations set - on the hydrodynamic wave properties is discussed. Sspecific solution of Riemann problem has been obtined.

The paper is devoted to construction of a numerical model and computations of continuously stratified fluid flows in field of external mass forces accounting for dissipative factors, viscosity and diffusion. Mathematical model is based on the fundamental set of differential equations of inhomogeneous multicomponent fluid mechanics. Solution of the problem is constructed numerically in the completenon-linear formulation using finite volume method in frame of the open source package OpenFOAM. To take in to account the stratification and diffusion effects a new own solver, stratifiedFoam, was developed and tested using the standard and extended libraries of the package. A particular attention is focused at construction of a high quality computational grid which satisfies basic requirements for resolution of all the microscales of the problem in high-gradient regions of the flow. The calculations performed in parallel regime on computational facilities of the web-laboratory UniHUB demonstrated a pretty high efficiency of the proposed numerical model and a good agreement with the experimental data.

The paper compares the results of mathematical modeling of aerodynamics typical urban developments with different length of the streets. The calculations were performed using the redistributable package OpenFoam and remote console access to the control node computing cluster BL2x220 Cluster Console https://unihub.ru/resources/bl2x220cc Web-laboratory Unihub (www.unihub.ru) program "University cluster" (www.unicluster.ru). Consider a single street with houses of the same height at its sides, a single street with houses of different heights at its sides and two parallel streets located on a hillside. Comparison of simulation results in two-dimensional and three-dimensional approximation showed that the length of the street has a significant impact on the qualitative and quantitative flow pattern inside the streets and on buildings.