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Ivannikov ISPras Open Conference (ISPras)

作者： Timofey Mezhuev Ilay Kobrin Alexey Vishnyakov Daniil Kuts Ivannikov Institute for System Programming of the RAS Moscow Russia Lomonosov Moscow State University Moscow Russia Yandex Cloud Moscow Russia

Numeric truncation is a widely spread error in software written in languages with static data typing, such as C/C++ or Java. It occurs when the significant bits of the value with a bigger type size are truncated during value conversion to the smaller type. Utilizing one of the most powerful methods for path exploration and automated bug detection called dynamic symbolic execution (DSE), we propose the symbolic security predicate for numeric truncation error detection, developed on top of DSE tool Sydr. Firstly, we execute the program on the data, which does not lead to any errors. During program execution we update symbolic shadow stack and shadow registers to track symbolic sizes of the symbolic variables to avoid false positives. Then, if we meet the instruction, which truncates the symbolic variable, we build the security predicate, try to solve it with the SMT-solver and in case of success save new input file to reproduce the error. We tested our approach on Juliet Dynamic test suite for CWE-197 and achieved 100% accuracy. We approved the workability of our approach by detecting 12 new errors of numeric truncation in 5 different real-world open source projects within OSS-Sydr-Fuzz project. All of the errors were reported, most of the reports were equipped with appropriate fixes, successfully confirmed and applied by project maintainers.

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Sydr: Cutting Edge Dynamic Symbolic Execution

Sydr: Cutting Edge Dynamic Symbolic Execution

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Ivannikov ISPras Open Conference (ISPras)

作者： Alexey Vishnyakov Andrey Fedotov Daniil Kuts Alexander Novikov Darya Parygina Eli Kobrin Vlada Logunova Pavel Belecky Shamil Kurmangaleev Ivannikov Institute for System Programming of the RAS Moscow Russia Lomonosov Moscow State University Moscow Russia Moscow Institute of Physics and Technology Moscow Russia

ISBN: (数字)9781665412919

ISBN: (纸本)9781665448215

The security development lifecycle (SDL) is becoming an industry standard. Dynamic symbolic execution (DSE) has enormous amount of applications in computer security (fuzzing, vulnerability discovery, reverse-engineering, etc.). We propose several performance and accuracy improvements for dynamic symbolic execution. Skipping non-symbolic instructions allows to build a path predicate 1.2-3.5 times faster. Symbolic engine simplifies formulas during symbolic execution. Path predicate slicing eliminates irrelevant conjuncts from solver queries. We handle each jump table (switch statement) as multiple branches and describe the method for symbolic execution of multi-threaded programs. The proposed solutions were implemented in Sydr tool. Sydr performs inversion of branches in path predicate. Sydr combines DynamoRIO dynamic binary instrumentation tool with Triton symbolic engine. We evaluated Sydr features on 64-bit Linux executables.

关键词： Instruments Switches Tools Maintenance engineering Performance analysis Engines Standards

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Multi-objective Optimization of Vehicle Routing with Environmental Penalty 10th

Multi-objective Optimization of Vehicle Routing with Environ...

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10th International Conference on Supercomputing, ISUM 2019

作者： Pulido-Gaytan, Luis Bernardo Tchernykh, Andrei Nesmachnow, Sergio Cristóbal-Salas, Alfredo Avetisyan, Arutyun Barrera, Harold Enrique Castro Hernandez, Carlos Jaime Barrios CICESE Research Center EnsenadaBC22860 Mexico Universidad de la República Montevideo Uruguay Universidad Veracruzana Veracruz Mexico Ivannikov Institute for System Programming of the RAS Moscow Russia University of Los Andes Bogotá Colombia Industrial University of Santander Bucaramanga Colombia

ISBN: (纸本)9783030380427

Cities host more than half of the population in only 2% of the earth’s surface and consume 75% of the resources extracted from the planet, this abrupt demographic growth in urban areas has worsened the level of pollution in the city, as well as the problems of road congestion. Therefore, smart cities propose the incorporation of technologies to optimize the use of existing infrastructure and thus, achieve a sustainable and inclusive city. In this context, we propose an optimization method based on a multi-objective cellular genetic algorithm to determine an adequate routing of vehicles that allows to diminish the environmental impact in highly concurred areas, while providing alternative routes that minimize the associated costs of moving from one place to another, this under the premise that not always the shortest path represents the best solution. The presented algorithm simultaneously minimizes three important objectives: the time, the amount of pollutants emitted and an environmental penalty, where the latter represents the implicit cost of moving through a certain segment of the map. That is, an approximate set of Pareto is obtained, which contains alternative routes that avoid traveling through areas with a high degree of pollution and that, in turn, minimize the time and quantity of emissions when traveling through a certain network of routes. Our experimental analysis based on several quality indicators, like Hypervolume and Spread, shows a competitive performance of the proposed approach in terms of convergence and diversity, this with respect to NSGA II and SPEA2, well-known multi-objective algorithms in the literature. © Springer Nature Switzerland AG 2019.

关键词： Multiobjective optimization

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Simulation of viscoelastic flow past circular airfoil by using the modified LS-STAG immersed boundary method 10

Simulation of viscoelastic flow past circular airfoil by usi...

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10th All-Russian Conference on Irreversible Processes in Nature and Technology

作者： Puzikova, Valeria V. Applied Mathematics Department Bauman Moscow State Technical University 2-ya Baumanskaya st. 5 str. 1 Moscow105005 Russia Compiler Technology Department Ivannikov Institute for System Programming of the RAS Alexander Solzhenitsyn st. 25 Moscow109004 Russia

The LS-STAG immersed boundary cut-cell method modification for viscoelastic flow computations is presented. Rate type viscoelastic flow models (linear and quasilinear) are considered. Rate type viscoelastic flow models (linear and quasilinear) are considered. The obtained numerical method is implemented in the LS-STAG software package developed by the author. This software allows to simulate viscous incompressible flows by using the LS-STAG method and it modifications. The LS-STAG-discretization of extra-stress equations for viscoelastic Maxwell, Jeffreys, upper-convected Maxwell, Maxwell-A, Oldroyd-B, Oldroyd-A, Johnson Segalman fluids was developed. Formulae for differential types of convected time derivatives (Oldroyd, Cotter-Rivlin, Jaumann-Zaremba-Noll derivatives) the LS-STAG discretization was obtained. Normal non-newtonian stresses are computed at the centers of base LS-STAG mesh cells and shear non-newtonian stresses are computed at the cell corners. Time-stepping algorithm is based on the first order predictor-corrector scheme. To validate developed numerical method the test problem about viscoelastic Oldroyd-B flow past a circular airfoil was used. Computational experiments were carried out at Weissenberg number in the range from 0 to 4. The computed values of the drag coefficients and the wake length are in good agreement with the experimental data. © Published under licence by IOP Publishing Ltd.

关键词： Airfoils

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Convergence analysis of stochastic gradient descent with adaptive preconditioning for non-convex and convex functions

arXiv

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arXiv 2023年

作者： Pasechnyuk, Dmitrii A. Gasnikov, Alexander Takáč, Martin Mohamed bin Zayed University of Artificial Intelligence United Arab Emirates Moscow Institute of Physics and Technology Russia Kharkevich Institute for Information Transmission Problems RAS Russia Ivannikov Institute for System Programming RAS Russia

Preconditioning is a crucial operation in gradient-based numerical optimisation. It helps decrease the local condition number of a function by appropriately transforming its gradient. For a convex function, where the gradient can be computed exactly, the optimal linear transformation corresponds to the inverse of the Hessian operator, while the optimal convex transformation is the convex conjugate of the function. Different conditions result in variations of these dependencies. Practical algorithms often employ low-rank or stochastic approximations of the inverse Hessian matrix for preconditioning. However, theoretical guarantees for these algorithms typically lack a justification for the defining property of preconditioning. This paper presents a simple theoretical framework that demonstrates, given a smooth function and an available unbiased stochastic approximation of its gradient, that it is possible to refine the dependency of the convergence rate on the Lipschitz constant of the *** Codes 65K10 © 2023, CC BY.

关键词： Stochastic systems

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Dynamic Diluted Taint Analysis for Evaluating Detected Policy Violations

Dynamic Diluted Taint Analysis for Evaluating Detected Polic...

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Ivannikov ISPras Open Conference (ISPras)

作者： Maksim Bakulin Maria Klimushenkova Danila Egorov Ivannikov Institute for System Programming of the RAS The Yaroslav-the-Wise Novgorod State University. Faculty of Computational Mathematics and Cybernetics Moscow State University

Dynamic taint analysis is a well-known technique. This article describes some difficulties that have to be dealt with when using dynamic taint analysis with full-system emulation. A new method is proposed to evaluate the risk of a detected policy violation. The method is called Diluted Taint: each tainted byte has an assigned integer value that shows how much taint resides in this byte. High value represents fresh taint, that possesses more threat, low value means that many operations occurred with this fragment of data and it is not that dangerous. When a policy violation occurs, these values are used by an expert to quickly evaluate the potential threat and prioritize fixing dangerous ones first.

关键词： Engines Security Instruments Registers Electronic mail Microsoft Windows

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Large language models in source code static analysis

Large language models in source code static analysis

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Ivannikov Memorial Workshop (IVMEM)

作者： V. N. Ignatyev N. V. Shimchik D. D. Panov A. A. Mitrofanov Ivannikov Institute for System Programming of the Russian Academy of Sciences (ISP RAS) Moscow Russian Federation Lomonosov Moscow State University Moscow Russian Federation

ISBN: (数字)9798331504663

ISBN: (纸本)9798331504670

Applications of Large Language Models (LLM) for source code analysis and related tasks arising during the development of an industrial static analyzer are becoming increasingly relevant due to the rapid development of LLM capabilities. The paper investigates several problems in the field of industrial static analysis, for which the use of LLM may be promising, provides quality evaluation of the results, key limitations and advantages for each one. Among the problems, the detection of “variable misuse” logic errors and the verification of warnings generated by the the static analysis tools are considered. In addition to tasks directly related to source code error detection, several methods have been developed to address supporting tasks in static analysis. These include generating specifications for library functions based on documentation and source code, as well as translating static analyzer tests developed for one programming language into another. All the methods were implemented within the infrastructure of the industrial static analyzer Svace and were tested on the dataset, which is used for Svace evaluation. Conclusions of results evaluation and possible integration to Svace for all proposed methods are discussed in the paper.

关键词： Computer languages Codes Source coding Large language models Conferences Static analysis Documentation

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Validation of a newly developed implementation of the PFEM-2 method using an open-source framework

Validation of a newly developed implementation of the PFEM-2...

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Ivannikov ISPras Open Conference (ISPras)

作者： Andrey Popov Ilia Marchevsky Georgy Serbin Bauman Moscow State Technical University Moscow Russia Ivannikov Institute for System Programming of the RAS Bauman Moscow State Technical University Moscow Russia

ISBN: (纸本)9781665423311

A description of a newly developed implementation of the Particle Finite Element Method, 2 nd generation (PFEM-2) is given. Main steps of the FEM and particles' parts of the algorithm are outlined. The results of its validation for a benchmark computation of a laminar flow are presented. Comparison with results obtained in the OpenFOAM code is also given.

关键词： Costs Codes Software packages Benchmark testing Libraries Finite element analysis Computational efficiency

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Boundary integral equation solving in vortex method using the Barnes-Hut/multipole algorithm

Boundary integral equation solving in vortex method using th...

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Ivannikov ISPras Open Conference (ISPras)

作者： Evgeniya Ryatina Ilia Marchevsky Alexandra Kolganova Bauman Moscow State Technical University Moscow Russia Bauman Moscow State Technical University Ivannikov Institute for System Programming of RAS Moscow Russia

The problem of efficient solution of the boundary integral equation arising at each time step in problems of 2D outer flow simulation by using the Vortex Particle Method is considered. It is necessary to develop an efficient approach to the corresponding linear system solving with the dense and non-symmetric matrix. For this purpose, an adaptation of the Barnes-Hut-based fast method, which has been initially developed for vortex particles velocities calculation, is suggested. The proposed modification is applied to the second-order numerical scheme with piecewise-linear solution representation since it allows considering vorticity distribution over far-placed panels, and performing integration of the local expansion coefficients over control panels that provides the satisfaction of the boundary condition in Galerkin sense. Besides the speedup effect, it does not require full matrix computation and storage, thus only about 1 % of matrix coefficients should be stored, which are calculated directly.

关键词： Linear systems Adaptation models Integral equations Boundary conditions Mathematical models Method of moments

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Local SGD for Near-Quadratic Problems: Improving Convergence under Unconstrained Noise Conditions

arXiv

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arXiv 2024年

作者： Sadchikov, Andrey Chezhegov, Savelii Beznosikov, Aleksandr Gasnikov, Alexander Moscow Institute of Physics and Technology Moscow Russia Ivannikov Institute for System Programming RAS Moscow Russia Sber AI Lab Moscow Russia Innopolis University Innopolis Russia

Distributed optimization plays an important role in modern large-scale machine learning and data processing systems by optimizing the utilization of computational resources. One of the classical and popular approaches is Local Stochastic Gradient Descent (Local SGD), characterized by multiple local updates before averaging, which is particularly useful in distributed environments to reduce communication bottlenecks and improve scalability. A typical feature of this method is the dependence on the frequency of communications. But in the case of a quadratic target function with homogeneous data distribution over all devices, the influence of frequency of communications vanishes. As a natural consequence, subsequent studies include the assumption of a Lipschitz Hessian, as this indicates the similarity of the optimized function to a quadratic one to some extent. However, in order to extend the completeness of the Local SGD theory and unlock its potential, in this paper we abandon the Lipschitz Hessian assumption by introducing a new concept of approximate quadraticity. This assumption gives a new perspective on problems that have near quadratic properties. In addition, existing theoretical analyses of Local SGD often assume bounded variance. We, in turn, consider the unbounded noise condition, which allows us to broaden the class of studied problems. Copyright © 2024, The Authors. All rights reserved.

关键词： Stochastic systems

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