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    Z3-Noodler 1.3: Shepherding Decision Procedures for Strings with Model Generation
    (Springer Verlag, 2025-05-03) Chocholatý, David; Havlena, Vojtěch; Holík, Lukáš; Hranička, Jan; Lengál, Ondřej; Síč, Juraj
    Z3-Noodler is a fork of the Z3 SMT solver replacing its string theory implementation with a portfolio of decision procedures and a selection mechanism for choosing among them based on the features of the input formula. In this paper, we give an overview of the used decision procedures, including a novel length-based procedure, and their integration into a robust solver with a good overall performance, as witnessed by Z3-Noodler winning the string division of SMT-COMP'24 by a  large margin. We also extended the solver with a support for model generation, which is essential for the use of the solver in practice.
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    Reconstruction and enhancement techniques for overcoming occlusion in facial recognition
    (Springer Nature, 2025-05-20) Pleško, Filip; Goldmann, Tomáš; Malinka, Kamil
    Face occlusions on CCTV cameras obscure important key facial features, preventing face recognition (FR) systems from recognizing people. This work mainly focuses on reconstructing these missing facial parts using Generative Adversarial Neural Networks (GANs) to improve FR accuracy while maintaining a low False Acceptance Rate (FAR). In addition, we are trying to improve the generated images further by using different image enhancement methods to test whether they can be used to improve the FR accuracy. To test the results, we perform experiments using state-of-the-art FR methods such as QMagFace and ArcFace to see whether image reconstruction and image enhancement help to improve FR accuracy.
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    Stokes problem with the Coulomb stick-slip boundary conditions in 3D: formulations, approximation, algorithms, and experiments
    (Elsevier, 2024-02-01) Haslinger, Jaroslav; Kučera, Radek; Šátek, Václav; Motyčková, Kristina
    The paper deals with the approximation and numerical realization of the Stokes system in 3D with Coulomb's slip boundary conditions. The weak velocity-pressure formulation leads to an implicit in- equality type problem which is discretized by the P1+bubble/P1 elements. To regularize the discrete non-smooth slip term and to release the discrete impermeability condition the duality approach is used. For numerical realization of the resulting saddle-point problem two strategies are proposed, namely i) its fixed-point formulation solved by the method of successive approximations ii) the direct numerical solu- tion of the saddle-point problem. The semi-smooth Newton method is used to solve non-smooth equations appearing in both these approaches.
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    Comparing Variable Handling Strategies in BDI Agents: Experimental Study
    (SciTePress - Science and Technology Publications, 2024-02-04) Vídeňský, František; Zbořil, František; Beran, Jan; Kočí, Radek; Zbořil, František
    BDI (Belief-Desire-Intention) agents represent a paradigm in artificial intelligence, demonstrating proficiency in reasoning, planning, and decision-making. They offer a versatile framework to construct intelligent agents capable of reasoning about their beliefs, desires, and intentions. Our research focuses on AgentSpeak(L), a popular BDI language, and its interpreter using late variable bindings. Unlike traditional interpreters, it defers substitution selection until execution, enhancing rationality by preventing premature, erroneous selections. To validate our approach, we conducted experiments in a virtual collectable card marketplace. We implemented a system that can use both late and early variable binding strategies, comparing their performance. In shared and independent experiments, the late bindings strategy outperformed the early bindings strategy, although overhead costs were observed. We also conduct a brief discussion of the situations in which it is appropriate to use late bindings given the structure of the declared plans.
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    Z3-Noodler: An Automata-based String Solver
    (Springer Verlag, 2024-04-04) Chen, Yu-Fang; Chocholatý, David; Havlena, Vojtěch; Holík, Lukáš; Lengál, Ondřej; Síč, Juraj
    Z3-Noodler is a fork of Z3 that replaces its string theory solver with a custom solver implementing the recently introduced stabilization-based algorithm for solving word equations with regular constraints. An extensive experimental evaluation shows that Z3-Noodler is a fully-fledged solver that can compete with state-of-the-art solvers, surpassing them by far on many benchmarks. Moreover, it is often complementary to other solvers, making it a suitable choice as a candidate to a solver portfolio.