Embedded devices may be significantly constrained in main memory, storage and CPU loads they can accommodate. The smaller the program, the faster it is loaded into memory. The smaller the system image, the cheaper can...
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Embedded devices may be significantly constrained in main memory, storage and CPU loads they can accommodate. The smaller the program, the faster it is loaded into memory. The smaller the system image, the cheaper can be production of the device. There are two ways to approach system image minification. The first way is to carefully write software adding no unnecessary parts from the start. The second way is to use existing software with unnecessary parts removed. In this work we implement the latter approach. Our work is concerned with eliminating unused code and data from dynamically linked programs; for statically linked programs, simple linker analysis is sufficient and has already been implemented.
Internal and inertial wave attractors appear as a result of propagation of waves obeying very specific dispersion relation. In closed containers, some boundaries of which are inclined with respect to the anisotropy di...
Internal and inertial wave attractors appear as a result of propagation of waves obeying very specific dispersion relation. In closed containers, some boundaries of which are inclined with respect to the anisotropy direction, this may result in domination of focusing of waves upon reflection, and after multiple reflections from the boundaries all the wave packets may be attracted by a closed loop or limit trajectory in physical space. It is well known that for wave attractors in plane geometries the change of the direction of anisotropy to the opposite will not change the geometry of the attractor and direction of flow of energy (in case of internal waves change of anisotropy direction means change of gravity direction and stratification growth). More complicated situation can arise for inertial wave attractors in fully 3D geometry. If we consider an annular layer with an inclined boundary, the change of the angle of inclination of a boundary to the opposite may also affect the geometry of the attractor, and the instability growth for higher amplitude of external forcing.
Open Source C++ code is developed for 2D incompressible flow simulation by using vortex methods. The code has modular structure, it permits users to simulate flow around airfoils (as well as around system of airfoils)...
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Open Source C++ code is developed for 2D incompressible flow simulation by using vortex methods. The code has modular structure, it permits users to simulate flow around airfoils (as well as around system of airfoils) and compute unsteady hydrodynamic loads acting the airfoils. It is also possible to simulate hydroelastic regimes of airfoil motion in the flow by using weakly coupled and strongly coupled algorithms. Well known vortex methods algorithms as well as original numerical schemes developed by authors are implemented, which makes it possible to raise the accuracy of simulation significantly in comparison to traditional algorithms of vortex methods. It is possible to run simulations in parallel mode, OpenMP and MPI technologies are supported. The source code of VM2D is available on GitHub under GNU GPL license (https://***/vortexmethods/VM2D).
We present the results of 3D-hydrodynamical simulations of accretion disk in close binary star system. The model includes the optical star filling its Roche lobe, a gas stream emanating from the inner Lagrangian point...
We present the results of 3D-hydrodynamical simulations of accretion disk in close binary star system. The model includes the optical star filling its Roche lobe, a gas stream emanating from the inner Lagrangian point of the binary system, and the accretion disc structure. A cold hydrogen gas stream is initially emitted towards a point-like gravitational centre. A stationary accretion disc is formed in about 5 orbital periods after the beginning of accretion. The model uses realistic cooling function for hydrogen. The simulation of accreting gas dynamics is performed using second order Runge — Kutta discontinuous Galerkin CFD solver for unstructured tetrahedral meshes. The monotonicity technique based on Hermite WENO solution reconstruction is implemented. Utilizing the hydrodynamical simulations the sinthetic light curves of the system are calculated as the volume emission of optically thin layers along the line of sight. The simulations results are in a good agreement with observations.
The next phase of LHC Operations – High Luminosity LHC (HL-LHC), which is aimed at ten-fold increase in the luminosity of proton-proton collisions at the energy of 14 TeV, is expected to start operation in 2027-2028 ...
The next phase of LHC Operations – High Luminosity LHC (HL-LHC), which is aimed at ten-fold increase in the luminosity of proton-proton collisions at the energy of 14 TeV, is expected to start operation in 2027-2028 and will deliver an unprecedented scientific data volume of multi-exabyte scale. This amount of data has to be stored and the corresponding storage system should ensure fast and reliable data delivery for processing by scientific groups distributed all over the world. The present LHC computing and data processing model will not be able to provide the required infrastructure growth even taking into account the expected hardware technology evolution. To address this challenge the new state-of-the-art computing infrastructure technologies are now being developed and are presented here. The possibilities of application of the HL-LHC distributed data handling technique for other particle and astro-particle physics experiments dealing with large-scale data volumes like DUNE, LSST, Belle-II, JUNO, SKAO etc. are also discussed.
This paper is devoted to a numerical simulation of 2D gas dynamics flows on uniform rectangular meshes using the Runge - Kutta - Discontinuous - Galerkin (RKDG) method. The RKDG algorithm was implemented with in-house...
This paper is devoted to a numerical simulation of 2D gas dynamics flows on uniform rectangular meshes using the Runge - Kutta - Discontinuous - Galerkin (RKDG) method. The RKDG algorithm was implemented with in-house C++ code based on the experience in the investigation of 1D case. The advantage of the RKDG method over the most popular finite volume method (FVM) is discussed: three basis functions being applied in the framework of the RKDG approach lead to a considerable decrease of the numerical dissipation rate with respect to FVM. The results of the acoustic pulse simulation on a sufficiently coarse mesh with the piecewise-linear approximation show a good agreement with the analytical solution in contrast to the FVM numerical solution. For the Sod problem, the results of the discontinuities propagation illustrate the dependence of the scheme resolution on the numerical fluxes, troubled cell indicator and the limitation technique choice. The possibility to resolve strong shocks is demonstrated with the Sedov cylindrical explosion test.
Visual spatial-temporal (4D) modeling technologies play an important role in the realization of complex construction projects and programs facing the problems of trustworthy planning, advanced communication among stak...
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The paper, basing on analysis of the Monte-Carlo Tree Search (MCTS) method and specific features of its behavior for various cases of usage, proposes a new variant of the method, which was called as Monte-Carlo Tree S...
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ISBN:
(纸本)9781509030071
The paper, basing on analysis of the Monte-Carlo Tree Search (MCTS) method and specific features of its behavior for various cases of usage, proposes a new variant of the method, which was called as Monte-Carlo Tree Search with Tree Shape Control (MCTS-TSC) and which uses original Depth-Width Criteria (DWCs) for both tree shape estimation and control during search and for estimation and selection of potentially better options for search continuation. Proposed Tree Shape Control (TSC) technique can be used with some other tuning, pruning, and learning techniques. Besides, it can provide better scheduling of MCTS parallelization.
Some problems connected to vortex methods development for 2D incompressible flow simulation around airfoils are discussed. In the numerical schemes and algorithms which are normally used in the vortex methods, the air...
Some problems connected to vortex methods development for 2D incompressible flow simulation around airfoils are discussed. In the numerical schemes and algorithms which are normally used in the vortex methods, the airfoil is approximated by a polygon consists of rectilinear panels, and the the vortex sheet intensity, which is placed on the airfoil surface line and simulates the airfoil's influence the flow, is assumed to be piecewise-constant or piecewise-linear function. The most accurate mathematical models and numerical algorithms, based on such approaches, provide the estimation for the order of the error between O(h) and O(h 2) for the average vortex sheet intensity over the panels (h is the maximal panel length). In the present research a new approach is developed, where the vortex sheet intensity is assumed to be discontinuous piecewise-linear or piecewise-quadratic function and the curvature of the panels is taken into account. In order to compute the coefficients of the main system of the algebraic equations, the least squares method is used instead of commonly used no-through or no-slip conditions at separate control points or over the panels in the average. It is shown, that the developed approach is much more accurate in comparison with previously known ones: for some test problems (flows around a circular airfoil, an elliptical airfoil and Zhukovsky airfoil) it permits to obtain numerical solution which has error of order O(h 4).
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