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Simulation of Vortex Interaction with a Shock Wave for Testing Numerical Algorithms

Mathematical Models and Computer Simulations 2023年第2期15卷 277-288页

作者： Kirushina, M.A. Elizarova, T.G. Epikhin, A.S. Keldysh Institute of Applied Mathematics Russian Academy of Sciences Moscow Russian Federation Ivannikov Institute for System Programming Russian Academy of Sciences Moscow Russian Federation

Abstract: The results of numerical simulation of the problem of the interaction of a vortex flow with a shock wave are presented on the example of using a quasi-gas dynamic (QGD) numerical algorithm, which is implemented as the QGDFoam solver. The algorithm is based on regularized equations of gas dynamics. The algorithm is implemented in the OpenFOAM open software package. The results are compared with the published data obtained based on the Godunov type method of a high order of accuracy and variants of the Kurganov–Tadmor method included in the open software package. © 2023, Pleiades Publishing, Ltd.

关键词： control volume method nonstationary supersonic ideal gas flow OpenFOAM package quasi-gas dynamic algorithm

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Generating dynamic 3D scenes for rendering benchmarks 13

Generating dynamic 3D scenes for rendering benchmarks

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13th International Conference on Interfaces and Human Computer Interaction 2019, IHCI 2019, 12th International Conference on Game and Entertainment Technologies 2019, GET 2019 and 13th International Conference on Computer Graphics, Visualization, Computer Vision and Image Processing 2019, CGVCVIP 2019

作者： Gonakhchyan, Vyacheslav Tarlapan, Oleg Semenov, Vitaly Ivannikov Institute for System Programming of the Russian Academy of Sciences Alexander Solzhenitsyn st. 25 Moscow109004 Russia

ISBN: (纸本)9789898533913

Performance comparison of different rendering methods is either based on synthetic 3D scenes or commonly used 3D scenes. A lot of static scenes exist but dynamic scenes are not common. Performance of modern rendering methods depends on the dynamic state of objects and varies with an increasing number of objects, degree of scene volatility. In this paper, two new methods of dynamic scene generation are proposed. We consider the bottlenecks of common rendering methods, based on which the parameters of the proposed methods are selected. We propose a method for dynamic scene generation, which allows to create scenes with a specified number of objects, vertices, different appearance order, temporal coherence of visibility, degree of spatial coherence of appearance and other parameters. We propose a method for converting of static scenes into dynamic scenes using space-filling curves to determine the order in which objects appear in a scene. The proposed methods will fill the gap in the field of rendering benchmarks and will allow to use the proven static scenes when evaluating the performance of methods with dynamic objects. © Copyright 2019 IADIS Press. All rights reserved.

关键词： Benchmarking

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Dedoc: A Universal system for Extracting Content and Logical Structure From Textual Documents

Dedoc: A Universal System for Extracting Content and Logical...

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2023 ivannikov ISPRAS Open Conference, ISPRAS 2023

作者： Belyaeva, Oksana Bogatenkova, Anastasiia Turdakov, Denis Ivannikov Institute for System Programming of the Russian Academy of Sciences Alexander Solzhenitsyn st. 25 Moscow109004 Russia

ISBN: (纸本)9798350349993

Document analysis has been a longstanding topic of research because of its great impact on a wide range of practical applications. The sheer number of different document formats and domains make this task particularly difficult. The existing solutions propose parsing documents of various formats, still there exists the problem of structure extraction for different document types. Dedoc is an open-source library that allows to extract document content in a unified representation and make it structuralized according to the specific domain of the document. The system architecture provides its scalability, i.e. the possibility to add new document formats and structure types handlers. © 2023 IEEE.

关键词： Extraction

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Symbolic Security Predicates: Hunt Program Weaknesses

Symbolic Security Predicates: Hunt Program Weaknesses

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2021 ivannikov Ispras Open Conference, ISPRAS 2021

作者： Vishnyakov, Alexey Logunova, Vlada Kobrin, Eli Kuts, Daniil Parygina, Darya Fedotov, Andrey Ivannikov Institute For System Programming Of The Ras Russia Lomonosov Moscow State University Russia Moscow Institute Of Physics And Technology Moscow Russia

ISBN: (纸本)9781665423304

Dynamic symbolic execution (DSE) is a powerful method for path exploration during hybrid fuzzing and automatic bug detection. We propose security predicates to effectively detect undefined behavior and memory access violation errors. Initially, we symbolically execute program on paths that don't trigger any errors (hybrid fuzzing may explore these paths). Then we construct a symbolic security predicate to verify some error condition. Thus, we may change the program data flow to entail null pointer dereference, division by zero, out-of-bounds access, or integer overflow weaknesses. Unlike static analysis, dynamic symbolic execution does not only report errors but also generates new input data to reproduce them. Furthermore, we introduce function semantics modeling for common C/C++ standard library functions. We aim to model the control flow inside a function with a single symbolic formula. This assists bug detection, speeds up path exploration, and overcomes overconstraints in path predicate. We implement the proposed techniques in our dynamic symbolic execution tool Sydr. Thus, we utilize powerful methods from Sydr such as path predicate slicing that eliminates irrelevant constraints. We present Juliet Dynamic to measure dynamic bug detection tools accuracy. The testing system also verifies that generated inputs trigger sanitizers. We evaluate Sydr accuracy for 11 CWEs from Juliet test suite. Sydr shows 95.59% overall accuracy. We make Sydr evaluation artifacts publicly available to facilitate results reproducibility. © 2021 IEEE.

关键词： Errors

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Sydr-Fuzz: Continuous Hybrid Fuzzing and Dynamic Analysis for Security Development Lifecycle

Sydr-Fuzz: Continuous Hybrid Fuzzing and Dynamic Analysis fo...

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2022 ivannikov Open Conference, ISPRAS 2022

作者： Vishnyakov, Alexey Kuts, Daniil Logunova, Vlada Parygina, Darya Kobrin, Eli Savidov, Georgy Fedotov, Andrey Ivannikov Institute for System Programming of the Ras Russia Moscow Institute of Physics and Technology Moscow Russia Lomonosov Moscow State University Russia

ISBN: (纸本)9798350398533

Nowadays automated dynamic analysis frameworks for continuous testing are in high demand to ensure software safety and satisfy the security development lifecycle (SDL) requirements. The security bug hunting efficiency of cutting-edge hybrid fuzzing techniques outperforms widely utilized coverage-guided fuzzing. We propose an enhanced dynamic analysis pipeline to leverage productivity of automated bug detection based on hybrid fuzzing. We implement the proposed pipeline in the continuous fuzzing toolset Sydr-Fuzz which is powered by hybrid fuzzing orchestrator, integrating our DSE tool Sydr with libFuzzer and AFL++. Sydr-Fuzz also incorporates security predicate checkers, crash triaging tool Casr, and utilities for corpus minimization and coverage gathering. The benchmarking of our hybrid fuzzer against alternative state-of-the-art solutions demonstrates its superiority over coverage-guided fuzzers while remaining on the same level with advanced hybrid fuzzers. Furthermore, we approve the relevance of our approach by discovering 85 new real-world software flaws within the OSS-Sydr-Fuzz project. Finally, we open Casr source code to the community to facilitate examination of the existing crashes. © 2022 IEEE.

关键词： Pipelines

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Double Layer Potential Density Reconstruction Procedure for 3D Vortex Methods 19th

Double Layer Potential Density Reconstruction Procedure for ...

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19th International Conference on Finite Elements in Flow Problems, FEF 2017

作者： Marchevsky, Ilia K. Shcheglov, Georgy A. Bauman Moscow State Technical University Moscow Russia Ivannikov Institute for System Programming of the Russian Academy of Sciences Moscow Russia

ISBN: (纸本)9783030307042

A new approach is developed for the no-slip boundary condition in vortex methods. The procedure of double layer potential density reconstruction is considered, which consist of two steps. Firstly the integral equation with respect to vortex sheet intensity is solved, which expresses the equality between the tangential components of flow velocity limit value and the body surface velocity. It is solved by using a Galerkin approach. Secondly, the least-squares procedure is implemented, which permits to find nodal values of the potential. It is shown that the developed algorithm makes it possible to improve significantly the quality of solution for the bodies with very complicated geometry and low-quality surface meshes. It can be useful for CFD applications and visual effects reproducing in computer graphics. © Springer Nature Switzerland AG 2020.

关键词： Boundary integral equations

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Adaptive Homing Sequences for Partial Weakly-initialized Observable FSMs

Adaptive Homing Sequences for Partial Weakly-initialized Obs...

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2021 IEEE East-West Design and Test Symposium, EWDTS 2021

作者： Vinarskii, Evgenii Tvardovskii, Aleksandr Yevtushenko, Nina Higher School of Economics Moscow Russia Tomsk State University Tomsk Russia Ivannikov Institute for System Programming of the RAS Moscow Russia

ISBN: (纸本)9781665445030

Finite State Machine (FSM) based state identification problem is widely used for analysis of discrete event systems. A homing sequence (HS) allows to determine the current state of an FSM under investigation. An HS is known to always exist and has polynomial length with respect to the number of states for a non-initialized reduced complete deterministic FSM where for each input sequence there is exactly one output sequence and any state can be an initial state. The HS problem becomes more complex if partial, non-deterministic or weakly-initialized machines are considered;for such FSMs an HS not always exists and can be much longer when existing. In particular, it has been proven that for a complete weakly-initialized non-deterministic FSM, length of a shortest adaptive HS (AHS) can be exponential with respect to the number of FSM states but HS length was not evaluated. In this paper, we consider the HS problem for partial observable possibly non-deterministic FSMs. In particular, we suggest a criterion for the existence of an AHS for a partial observable FSM and estimate the length of a shortest AHS. © 2021 IEEE.

关键词： Automata Discrete-event systems

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Numerical Simulation of Propeller Hydrodynamics Using the Open Source Software 1

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23rd International Conference on Computational Science, ICCS 2023

作者： Britov, Andrey Yarikova, Sofya Epikhin, Andrey Elistratov, Stepan Zhang, Qin Ivannikov Institute for System Programming of the RAS Moscow Russia Shirshov Institute of Oceanology of the RAS Moscow Russia Ocean University of China Qingdao China

ISBN: (数字)9783031360305

ISBN: (纸本)9783031360299

The paper presents the results of numerical simulation of the propeller Ka4-70 using the actuator line model in the OpenFOAM, AMReX and Nek5000 open-source software. The modifications of the tools for wind farm simulation for these packages are carried out. Features of these implementation are described. For numerical calculations the LES and IDDES turbulence models are used. A comparison of the computational costs and accuracy of flow structures are made for the actuator line model using different methods and the arbitrary mesh interface approach. The actuator line model provides force characteristics and flow structures with good enough accuracy. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

关键词： Actuators

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Advanced Grammar-Based Fuzzing

Advanced Grammar-Based Fuzzing

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2022 ivannikov Memorial Workshop, IVMEM 2022

作者： Sargsyan, Sevak Hakobyan, Jivan Mehrabyan, Matevos Mkoyan, Ruslan Sahakyan, Vardan Melkonyan, Vahagn Arutunian, Mariam Fahradyan, Arman Avetisyan, Arutyun Russian-Armenian University Center of Advanced Software Technologies Yerevan Armenia Programming of the RAS Ivannikov Institute for System Moscow Russia

ISBN: (数字)9781665492973

ISBN: (纸本)9781665492973

This article presents novel method for efficient fuzzing of programs accepting complex structured data. It generates input data based on formal grammar description. Data generator is periodically autoconfigured based on target programs code coverage. It means that the type of generated programs is dynamically changed to increase code coverage. Data generator uses descriptions of BNF (Backus-Naur Form) rules in ANTLR (ANother Tool for Language Recognition) platform. More than 250 languages and data formats are supported. Every rule of grammar is designed as universal pushdown automata, which allows automatically generate BNF compatible data by traversing automata. We added weights for each transition of automata to provide priority of highly efficient paths (sequence of transitions). These weights are automatically changed by fuzzing engine, which provides data generator adaptation based on the coverage of the target programs. According to experimental results, we were able to increase code coverage significantly for several widely used programs including compilers. © 2022 IEEE.

关键词： Automata theory

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The Algorithm of the Vortex Sheet Intensity Determining in 3D Incompressible Flow Simulation around a Body

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Mathematical Models and Computer Simulations 2020年第4期12卷 464-473页

作者： Marchevskii, I.K. Shcheglov, G.A. Bauman Moscow State Technical University Moscow Russian Federation Ivannikov Institute for System Programming Russian Academy of Sciences Moscow 109004 Russian Federation

Abstract: An original algorithm is developed for vortex methods of computational fluid dynamics for determining the intensity of the vortex sheet on the surface of a body in the flow of an incompressible medium. Unlike the common in the vortex methods approach to satisfying the no-slip boundary condition on a streamlined surface, which is based on ensuring that the normal velocity component of the medium is zero, the proposed procedure is based on a mathematically equivalent condition of equality to zero of the tangent velocity component on the body surface. The unknown intensity of the vortex sheet is assumed to be piecewise constant on triangular panels that approximate the surface of the body. The resulting integral equation is approximated by a system of linear algebraic equations, which dimension is twice the number of panels. The coefficients of the system matrix are expressed through double integrals over the panels. An algorithm is proposed for calculating these integrals for the case of neighboring panels, when these integrals are improper. An additive singularity exclusion is performed and analytical expressions for the integrals of them are obtained. The smooth parts of integrands are integrated numerically using Gaussian quadrature formulae. The proposed algorithm makes it possible to improve significantly the accuracy of the vortex sheet intensity reconstruction when flow simulating around complex-shaped bodies by using vortex methods for arbitrary triangular surface meshes, including essentially non-uniform and having cells with high aspect ratio. © 2020, Pleiades Publishing, Ltd.

关键词： Biot−Savart law boundary integral equation incompressible media vortex influence vortex method vortex sheet

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