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Alias Analysis in C Compiler
Bolvanský, Dávid ; Zachariášová, Marcela (referee) ; Hruška, Tomáš (advisor)
This thesis is dedicated to the problem of alias analysis and possibilities of its improvement in the LLVM framework. The goal of this thesis is to improve the accuracy, which was achieved by extending the existing implementation of Andresen algorithm to be field sensitive. The terms related to alias analysis and algorithms of the alias analysis available in LLVM are explained. These algorithms are compared according to their base idea, features, and limitations. The implementation of the field sensitivity has been tested using compiler test suites. Its impact on program compilation speed and performance has been analyzed. The measured results show an increase in the accuracy of alias analysis in the LLVM framework.
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Simulator for Verifying the Properties of DAG-Based Consensus Protocols
Hladký, Tomáš ; Tamaškovič, Marek (referee) ; Malinka, Kamil (advisor)
V posledných rokoch sa vo výskumnej komunite venuje blockchainu významná pozornosť. Odvtedy bolo navrhnutých niekoľko návrhov na riešenie problému priepustnosti blockchainov založených na Proof-of-Work. V tejto práci študujeme existujúce návrhy blockchainu s acyklicky orientovaným grafom (DAG), ktoré navrhujú riešenie spomínaného problému, najmä protokol PHANTOM (a jeho optiamlizácia GHOSTDAG). Využívajú bitcoinový protokol a navrhujú náhodný výber transakcií, čo vedie k zvýšeniu priepustnosti transakcií. Simuláciou sa však dokázalo, že aktéri, ktorí využívajú stratégiu náhodného výberu transakcií, majú menší zisk ako aktéri, ktorí nedodržiavajú protokol a vyberajú transakcie racionálne (t.j. najziskovejšie). Tento dôkaz bol vykonaný na malej sieti desiatich uzlov s kruhovou topológiou. Cieľom tohto článku je rozšíriť, optimalizovať a automatizovať existujúci simulátor blockchainu. Implementujeme sieťovú topológiu podobnú bitcoinu s realistickou latenciou šírenia blokov. Okrem toho optimalizujeme simulátor tak, aby sme mohli spúšťať viac simulácií paralelne a rýchlejšie, vrátane automatizačných nástrojov, ktoré môžu upravovať vstupné konfigurácie, vykonávať kombináciu simulácii na viacerých jadrách CPU na základe vstupných parametrov a analyzovať zisky a kolízie transakcií. Nakoniec vykonáme experimenty na overenie výhod škodlivých aktérov v sieti podobnej Bitcoinu a vytvoríme výplatnú funkciu na potrestanie tohto správania.
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Traceability of Optimized Generated Code
Gavenda, Daniel ; Rychlý, Marek (referee) ; Křivka, Zbyněk (advisor)
The goal is to create an application that analyzes the optimizations applied during the translation of an input model into the corresponding generated code. This analysis will be provided to developers in order to show sources of potential automated review failures. In this case, the analysis reports should serve as a guide to a model designer to transform the model to avoid problematic optimizations.
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Design of sewer network rehabilitation of choice parts of urbanized areas
Horák, Ondřej ; Malaník, Stanislav (referee) ; Raclavský, Jaroslav (advisor)
The thesis approaches the problem of design of sewer network rehabilitation of urbanized area named Kamenná čtvrť. The thesis is divided into several parts. In the first part of the thesis there is the accompaying report, which describs characteristics of the area as a whole. The second part of the thesis is about describing each part of the network, clasification of defects according to the ČSN EN 13508 -2 and fothcoming TNV 75 6905 and photographs from network camera survey. In the third part of this thesis there is a chart with all defects located on the network. Also there is an evaluation of each part of network according to prepared TNV 75 6905. The fourth part of the thesis talks about evaluation of each part of the network as a whole. In the fifth part of the thesis we design possible choises of reahabilitation on the network. The sixth part of the thesis contains the economic aspects of possible alternatives and their comparsion. Last part of the thesis contains a hydrotechnical calculation, which means calculation of the current situation and the possible alternatives. There is an individual evaluation of the calculation and if its necessary optimizations of the network.
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Modelling of Load Impacts Acting on Transport and Handling Equipments with the Aim of their Optimization
Šťastný, Antonín ; Hrabovský, Leopold (referee) ; Kuľka,, Jozef (referee) ; Škopán, Miroslav (advisor)
This PhD thesis deals with employment of the state of the art methods of mathematical optimization and structural analysis in the field of load carrying steel structures of handling devices. The goal of the thesis is to compile a methodology which enables generating of optimal dimensions of conceptually designed load carrying parts of handling devices. The proposed methodology is composed of sub-methods which are successively applied to find an optimal configuration of structure according to a chosen criterion. The methodology incorporates sub-methods such as Design of Experiments, parametric finite-element modelling, the state of the art computational methods for stability assessment, mathematical approximation methods and state of the art optimization schemes based of both, heuristic and gradient principle. Recommendations from Eurocode 3 are used to introduce imperfections to the finite element model in order to perform the nonlinear buckling analysis. The practical part of this thesis is focused on optimization of welded beams. The principle of the methodology is in detail explained and demonstrated on an example of lifting spreader beam of load carrying capacity of 20 tons. The proposed methodology is practically realized by an algorithm created in Matlab software. Matlab is also utilized to implement some sub-methods including mathematical optimization schemes. Both, gradient and heuristic optimization algorithms are used for comparison and mutual verification. Structural analysis is performed by means of parametrical finite-element models which are built in the Ansys Parametric Design Language (APDL). The methodology takes into account buckling, which is inherent to thin walled structures under compressive load. The buckling analysis is performed by means of both, linear and non-linear procedures in Ansys. The output of the algorithm is an optimized configuration of the structure, which minimizes the objective function and complies with all requirements implemented in the form of design constraints.
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An Efficient Way to Allocate and Read Directory Entries in the Ext4 File System
Pazdera, Radek ; Michal, Bohumil (referee) ; Kašpárek, Tomáš (advisor)
Cílem této práce je zvýšit výkon sekvenčního procházení adresářů v souborovém systému ext4. Datová struktura HTree, jenž je v současné době použita k implementaci adresářu v ext4 zvládá velmi dobře náhodné přístupy do adresáře, avšak není optimalizována pro sekvenční procházení. Tato práce přináší analýzu tohoto problému. Nejprve studuje implementaci souborového systému ext4 a dalších subsystému Linuxového jádra, které s ním souvisí. Pro vyhodnocení výkonu současné implementace adresářového indexu byla vytvořena sada testů. Na základě výsledků těchto testů bylo navrženo řešení, které bylo následně implementováno do Linuxového jádra. V závěru této práce naleznete vyhodnocení přínosu a porovnání výkonu nové implementace s dalšími souborovými systémy v Linuxu.
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P4.16 Compiler Using High Level Synthesis
Neruda, Jakub ; Kekely, Lukáš (referee) ; Martínek, Tomáš (advisor)
The P4 language is currently a hot topic in the field of network administration due to its capability to program the functionality of network devices. This language is still in development and its last revision P416 drastically changed not only the language features and syntax, but also the underlying compiler. The CESNET association supports the development of the P4 language and thus they also need to support the new standard. This work examines possible problems tied to migration, namely issues related to translation of high-level user-defined actions into VHDL description, with the help of High-level Synthesis (HLS), instantiation of so-called extern objects and the support of atomic sections. The text discusses possible ways of interconnecting the HDL components and organisation of their memory space in order to support configuration from software at runtime. The architecture of the p4c compiler is also described, complete with code examples implementing core classes participating in the compilation process. The last part of the work showcases the usage of Vivado HLS for optimizing C++ code in order to get maximum performance from the resulting firmware.
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Traceability of Optimized Generated Code
Gavenda, Daniel ; Rychlý, Marek (referee) ; Křivka, Zbyněk (advisor)
The goal is to create an application that analyzes the optimizations applied during the translation of an input model into the corresponding generated code. This analysis will be provided to developers in order to show sources of potential automated review failures. In this case, the analysis reports should serve as a guide to a model designer to transform the model to avoid problematic optimizations.
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Simulator for Verifying the Properties of DAG-Based Consensus Protocols
Hladký, Tomáš ; Tamaškovič, Marek (referee) ; Malinka, Kamil (advisor)
V posledných rokoch sa vo výskumnej komunite venuje blockchainu významná pozornosť. Odvtedy bolo navrhnutých niekoľko návrhov na riešenie problému priepustnosti blockchainov založených na Proof-of-Work. V tejto práci študujeme existujúce návrhy blockchainu s acyklicky orientovaným grafom (DAG), ktoré navrhujú riešenie spomínaného problému, najmä protokol PHANTOM (a jeho optiamlizácia GHOSTDAG). Využívajú bitcoinový protokol a navrhujú náhodný výber transakcií, čo vedie k zvýšeniu priepustnosti transakcií. Simuláciou sa však dokázalo, že aktéri, ktorí využívajú stratégiu náhodného výberu transakcií, majú menší zisk ako aktéri, ktorí nedodržiavajú protokol a vyberajú transakcie racionálne (t.j. najziskovejšie). Tento dôkaz bol vykonaný na malej sieti desiatich uzlov s kruhovou topológiou. Cieľom tohto článku je rozšíriť, optimalizovať a automatizovať existujúci simulátor blockchainu. Implementujeme sieťovú topológiu podobnú bitcoinu s realistickou latenciou šírenia blokov. Okrem toho optimalizujeme simulátor tak, aby sme mohli spúšťať viac simulácií paralelne a rýchlejšie, vrátane automatizačných nástrojov, ktoré môžu upravovať vstupné konfigurácie, vykonávať kombináciu simulácii na viacerých jadrách CPU na základe vstupných parametrov a analyzovať zisky a kolízie transakcií. Nakoniec vykonáme experimenty na overenie výhod škodlivých aktérov v sieti podobnej Bitcoinu a vytvoríme výplatnú funkciu na potrestanie tohto správania.
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Alias Analysis in C Compiler
Bolvanský, Dávid ; Zachariášová, Marcela (referee) ; Hruška, Tomáš (advisor)
This thesis is dedicated to the problem of alias analysis and possibilities of its improvement in the LLVM framework. The goal of this thesis is to improve the accuracy, which was achieved by extending the existing implementation of Andresen algorithm to be field sensitive. The terms related to alias analysis and algorithms of the alias analysis available in LLVM are explained. These algorithms are compared according to their base idea, features, and limitations. The implementation of the field sensitivity has been tested using compiler test suites. Its impact on program compilation speed and performance has been analyzed. The measured results show an increase in the accuracy of alias analysis in the LLVM framework.
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