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High-Level Programming Language Transpilers
Mokriš, Andrej ; Havel, Martin (referee) ; Meduna, Alexandr (advisor)
Rýchly vývoj programovacích jazykov priniesol radu praktických problémov, napríklad obmedzenú spätnú kompatibilitu. Časť týchto problémov môže byť riešená transpilátormi. Táto práca predstavuje základné koncepty z teórie formálnych jazykov, prekladačov a prístupov k syntaktickej analýze. Cieľom práce je navrhnúť a implementovať transpilátor, ktorý prekladá podmnožinu jazyka PHP do jazyka JavaScript.
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Development of YARA-X ecosystem
Ďuriš, Tomáš ; Křivka, Zbyněk (referee) ; Regéciová, Dominika (advisor)
The aim of this work is to extend and create an unified ecosystem of tools for the YARA language. The focus is on incorporating modules that can gather information about the structure of executable files. Additionally, a module that can present obtained information to the user in multiple formats is also being proposed. An interactive environment has been created for evaluating YARA rules and enhancing the overall ecosystem by using an error-tolerant parsing algorithm. The proposed solution enables the seamless integration and utilization of existing tools while addressing the limitations of the original YARA ecosystem. The output of the work is an extended system with tools that facilitate the debugging of YARA rules, obtaining information from executable files, and visualizing them. The final solution has been thoroughly tested, utilized by analysts, and integrated into main YARA-X branch.
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Applying formal methods to analysis of semantic differences between versions of software
Nečas, František ; Vojnar, Tomáš (referee) ; Malík, Viktor (advisor)
Cílem této práce je navrhnout integraci formálních metod pro DiffKemp, nástroj pro statickou analýzu sémantických rozdílů v rozsáhlých programech napsaných v jazyce C. Cílem tohoto rozšíření je umožnit analýzu složitějších změn, které by typicky byly analyzovatelné spíše nástroji založenými na formálních metodách, a zároveň zachovat škálovatelnost nástroje DiffKemp na velké projekty. Principem navrženého řešení je při analýze v případě nalezení možné sémantické změny zakódovat problém ekvivalence příslušných instrukcí jako instanci problému SMT. Tím je možné sémantický rozdíl potvrdit, nebo vyvrátit s pomocí SMT solveru. Navržené řešení bylo implementováno v nástroji DiffKemp a experimenty provedené na sadě programů zvané EqBench ukazují, že rozšiřuje schopnosti nástroje DiffKemp, převážně v oblasti přesné analýzy úprav aritmetických výrazů.
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Určení spolehlivosti výsledků statické analýzy pomocí strojového učení
Beránek, Tomáš ; Fiedor, Jan (referee) ; Vojnar, Tomáš (advisor)
Statický analyzátor Meta Infer je nástrojem pro hledání různých typů chyb ve zdrojovém kódu. Jeho výsledky však obsahují více než 95 % falešných hlášení. Tato teze navrhuje řešení, které řadí hlášení od Meta Inferu pomocí grafových neuronových sítí (GNN) podle pravděpodobnosti, že se jedná o skutečnou chybu, a redukuje tak problém s falešnými hlášeními. Systém se skládá z trénovací části, která převádí datovou sadu D2A – sadu roztříděných hlášení z Meta Inferu – na rozšířené grafy vlastností kódu (ECPG) a z modelů GNN natrénovaných na ECPG grafech. Výsledky experimentů ukazují, že vytvořené modely GNN mohou konkurovat a v některých případech dokonce překonat existující řešení vyvíjené silnými průmyslovými týmy. Tato existující řešení mají navíc uzavřený zdrojový kód, a tak řešení vytvořené v této tezi poskytuje slibnou alternativu s otevřeným zdrojovým kódem.
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Impact of AI Tools on Code Quality and Security
Vinarčík, Peter ; Holop, Patrik (referee) ; Malinka, Kamil (advisor)
Táto práca predstavuje novovytvorenú aplikáciu, ktorá je schopná vykonávať large scale výskum pre hodnotenie bezpečnosti a kvality kódu generovaného AI. Tiež bol predstavený nový spôsob vyhodnocovania bezpečnosti kódu generovaného AI, za využitia MITRE's metodológie v kombinácii so SAST toolmi vykonávajúcimi statickú analýzu nad kódom. Aplikácia je navyše rozšírená o vylepšeného AI chatbota, ktorého výstup je obohatený o výsledky statickej analýzy v čase generovania. Užívateľ vloží dataset promptov do aplikácie, a v prípade, že bol pre určitý prompt vygenerovaný kód so zraniteľnosťou, je táto zraniteľnosť ohodnotená zavedenou metodológiou a užívateľ dostáva informáciu nie len o tom, že kód je zraniteľný, ale ako veľmi. Súčasťou riešenia je aj oproti existujúcim výskumom veľké, pilotné testovanie popularných AI ako ChatGPT-4 či Gemini, nad datasetom promptov s využitím novej aplikácie. Výsledky ukázali dominanciu ChatGPT-4 bežiacom na modeli GPT-4, oproti ostatným testovaným AI.
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Lab tasks for dynamic code analysis
Košina, Petr ; Přinosil, Jiří (referee) ; Sysel, Petr (advisor)
The thesis focuses on static and dynamic analysis in software engineering. Static analysis involves examining the source code without executing it, whereas dynamic analysis focuses on executing the code and testing its runtime behavior. The thesis explores various techniques and tools for both types of analysis, including their advantages and limitations. Additionally, the content includes research on the implementation of dynamic code analysis methods across different operating systems. Emphasis is placed on comparing both methods and their application in real-world software environments. Specifically, it provides practical laboratory exercises designed to help students better understand the issues related to dynamic analysis.
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Using optimization methods to design machine parts
Kubrický, Daniel ; Pokorný, Přemysl (referee) ; Zeizinger, Lukáš (advisor)
This bachelor thesis describes using structural optimization methods to design machine parts. In the first part of the thesis, a description of the current state of knowledge of the optimization process was made together with its theoretical background. In the second part of the thesis, a static analysis and topology optimization or Generative design was developed using the example of a bell crank in six commercial software. In the third part, the resulting models of each software were compared with each other, and the results were compared using the von Mises maximum stress criterion and the overall model deformation. Finally, this work was concluded with an evaluation of the use of the structural optimization software.
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Form finding of shell structures
Musil, Jiří ; Bažant, Zdeněk (referee) ; Vítek,, Jan (referee) ; Stráský, Jiří (advisor)
The theme of this doctoral thesis is the design of concrete shell structures with the focus on finding their optimal shape. The optimal shape of a concrete shell is the shape in which for a given load (usually the dead weight of the structure) no significant bending moments are generated in the shell and the structure is in the so-called membrane state. The inspiration for this thesis is the work of Swiss engineer Heinz Isler, who developed the shapes of shell structures using model tests of appropriately loaded flexible membranes. He developed the shell structure for large spans by inverting the resultant shape, which carried its weight almost entirely via membrane forces. The numerical solution of the above experiments using Midas Civil is presented herein. The basic principles of the method are demonstrated on the example of sagged cable. The numerically found shapes are compared with the analytical solution. A shell is designed based on the numerically found shapes and its stress response to dead load is described, particularly in relation to the membrane action. In the next part, the acquired knowledge and methods were used to design three relatively complicated shell structures. Each structure was statically analysed and its static behaviour was described. Structures with perfectly rigid or flexible supports, which simulate real behaviour of the supports, were studied. In the final phase, the results of static analysis of the selected shell were experimentally verified on a physical model in a scale of 1: 55.56. The model has been built using 3D printing. The thesis describes the use of a modelling similarity, the model design, the production process, and the experiment. The load test confirmed the optimal design of the shell structure and the validity of the numerical method for finding their shapes.
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Influence of seismic load on behavior of reinforced concrete frame.
Zlámalová, Pavlína ; Nováček, Jan (referee) ; Zich, Miloš (advisor)
The aim of this work is a static analysis of the reinforced concrete frame structure loaded by the effects of seismic loading. The work deals with the solution of multi-storey reinforced concrete structure designed for common loading conditions and further for possibilities of strengthening of the structure on effect of seismic loading. In the first phase of the work, the static analysis and the design of the main load-bearing elements of the frame structure (columns and main girder) were carried out for the ultimate limit state for the standard design load. In the second phase, the static analysis of the structure for the effects of accidental actions from low and high seismicity was performed and it was assessed whether the main load-bearing elements of the structure would continue to comply. Given that the structure did not satisfy the accidental actions of seismic loading, various ways of structure strengthening were designed and analyzed for their impact on the global and local behaviour of the structure. Also the designing of additional steps for structural reliability were performed. Static analyzes were performed in Scia Engineering and RFEM Dlubal software.
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Analysis of Mechanical Stress during Short Circuit in an Air-Insulated MV Switchgear
Bártů, Jan ; Bajánek, Tomáš (referee) ; Orságová, Jaroslava (advisor)
This Master thesis is based on problems of force effects of the magnetic field of short-circuit current. Firstly, I analysed the force action of the three phase busbars during the three-pole short circuit. The analysis was performed in the Ansys Maxwell program and I verified the correctness of the analysis by numerical calculation. The second practical part was executed for ABB company. The main task was to analyse the force effects of the short-circuit current in the HV switchgear with focusing on the arms and contact system of the circuit breaker. The simulations of the following configurations were performed in more details: three configurations of the simplified VD4 circuit breaker, two types of VD4 circuit-breaker contact systems and a linear circuit breaker configuration model. The objective was to calculate the forces acting on the current path of the arms and contact system of the VD4 circuit breaker during the three-phase short-circuit and to simulate the effects of forces on these current parts. For modelling of individual assemblies, calculations and simulations I used: SolidWorks 2014, Ansys Maxwell 16.0 and Ansys Workbench 14.5 programs. With SolidWorks 2014 3D CAD software were modelled simplified assemblies of circuit breakers and contact systems. These systems were imported into the Ansys Maxwell software, where the force effects of the magnetic field of the short-circuit current were calculated. In Ansys Workbench programme was simulated the effect of forces on the current circuit breakers. Moreover, the final deformations of the materials (with respect to the mechanical properties of the structure) were plotted. The analysis of force effects of the magnetic field was performed for the specified static short - circuit current value.
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