Utilization of Evolutionary Algorithms in Symbolic Regression Problem

Evoluční techniky jsou neustále se vyvíjející a progresivní část informatiky. Evoluční algoritmy se v praxi používají k řešení mnohých druhů problémů od optimalizace až k plánování. Tato práce se zabývá genetickým a kartézským genetickým programováním, které patří mezi nejčastěji používané algoritmy. Cílem práce je implementovat jednotlivé přístupy a vyhodnotit jejich účinnost v úloze symbolické regrese.Evolutionary algorithms are constantly developing and progressive part of informatics. These algorithms serve to solve many kinds of problems from optimal control to planning. This study discusses genetic and cartesian genetic programming, which belong among the most successful types of evolutionary algorithms. The goal of this work is to develop two aplications of genetic and cartesian genetic programming and evaluate efficiency of these two types of evolutionary algorithms in solving symbolic regression problems.

Optimal Trade Execution Under Endogenous Pressure to Liquidate: Theory and Numerical Solutions

We study optimal liquidation of a trading position (so-called block order or meta-order) in a market with a linear temporary price impact (Kyle, 1985). We endogenize the pressure to liquidate by introducing a downward drift in the unaffected asset price while simultaneously ruling out short sales. In this setting the liquidation time horizon becomes a stopping time determined endogenously, as part of the optimal strategy. We find that the optimal liquidation strategy is consistent with the square-root law which states that the average price impact per share is proportional to the square root of the size of the meta-order (Bershova and Rakhlin, 2013; Farmer et al., 2013; Donier et al., 2015; T´oth et al., 2016). Mathematically, the Hamilton-Jacobi-Bellman equation of our optimization leads to a severely singular and numerically unstable ordinary differential equation initial value problem. We provide careful analysis of related singular mixed boundary value problems and devise a numerically stable computation strategy by re-introducing time dimension into an otherwise time-homogeneous task

Multimedia Diff - Audio Documents

Tato práce se zabývá vývojem nástroje, který umožňuje funkci diff nad audio soubory obsahujícími obecný zvuk jako hudbu, řeč a jiné zvuky. Jsou zde uvedeny poznatky z různých oblastí vědy zabývající se zvuky jako například psychoakustiky, zpracování řeči a automatické kategorizace hudby podle žánru. Jsou zde popsány některé algoritmy diffu a také externí nástroje potřebné pro vývoj cílové aplikace. Dále tato práce uvádí návrh a implementaci výsledné aplikace, nastavení použitá pro extrakci charakteristických znaků zvuku a zhodnocení dosažených výsledků.This work describes development of a diff tool working with audio files containing general sound such as music, speech and other sounds. There are presented facts from different domains of science related to sound, such as psychoacoustics, speech recognition and automatic music genre categorisation. This paper also contains description of some diff algorithms and external tools needed for development of the goal application. Moreover, there is introduced design and implementation of the application, settings used for sound features extraction and evaluation of attained results.

IEEE 802.15.4 range measurements

Diplomová práce Měření dosahu IEEE 802.15.4 měla v první části za cíl zjistit, zda mají vliv na bezdrátovou komunikaci mezi dvěma moduly ZigBee různé atmosférické podmínky. Odpověď jsem chtěl najít pomocí dlouhodobého měření, protože ale nebylo možné najít vhodné místo pro měření, odpověď jsem hledal v literatuře. V druhé části diplomové práce jsem měřil vliv na kvalitu signálu, jestliže jeden modul byl umístněný v automobilu. V rámci měření jsem umístnil moduly do různých částí auta, na palubní desce, na sedadle spolujezdce, v přihrádce před spolujezdcem a v zavazadlovém prostoru. Automobil pro měření byl použit Renault Scénic r.v. 2004.In the master’s thesis IEEE 802.15.4 Range measurements I want to find out, whether atmospheric conditions have influence over the quality of communication between two ZigBee modules. I would like found the answer by long-time test, because I can’t found the proper place for the measuring, I must found the answer in the literature. In the second part of the master’s thesis I measuring, whether placing one of the module in the car have influence over the quality of communication. The module was placing in the various places in the car, on a dashboard, on a guest-passenger’s seat, in a pocket before guest-passenger and in luggage compartment. The car for the measuring was used Renaul Scénic my. 2004.

Cationic Polymerization of 1,2-Epoxypropane by an Acid Exchanged Montmorillonite Clay in the Presence of Ethylene Glycol

Abstract: The polymerization of propylene oxide (PO) catalysed by maghnite-H+ (mag-H+) in the presence of ethylene glycol was investigated. Mag-H+ is a montmorillonite silicate sheet clay was prepared through a straight forward proton exchange process. It was found that the cationic polymerization of PO was initiated by mag-H+ at 20 °C both in bulk and in solution. The effect of the amount of mag-H+ and solvent was studied. These results indicated the cationic nature of the polymerization A possible initiation pathway, via the transfer of protons from mag-H+ to the monomer, is proposed

Selective methoxylation of α-pinene to α-terpinyl methyl ether over Al3+ ion-exchanged clays

In this study, we report the use of clay-based catalysts in the methoxylation of α-pinene, for the selective synthesis of α-terpinyl methyl ether, TME. The main reaction products and intermediates were identified by GC-MS. The reaction conditions (stirring rate and catalyst load) that afford a kinetic regime were established. SAz-1 (Cheto, Arizona, USA) source clay and a montmorillonite (SD) from Porto Santo, Madeira Archipelago, Portugal, were modified by ion-exchange with Al3+ to produce catalysts with markedly different acidities and textural properties. The catalysts based on the high layer-charge SAz-1 montmorillonite proved to be the most active. Ion-exchange with Al3+, followed by thermal activation at 150°C, afforded the highest number of Brønsted acid sites - a significant proportion of which were located in the clay gallery - and this coincided with the maximum catalytic activity. The influence of various reaction conditions, to maximize α-pinene conversion and selectivity, was studied over AlSAz-1. When the reaction was performed for 1 h at 60°C, the conversion reached 65% with 65% selectivity towards the mono-ether, TME. Similar conversions and selectivities required up to 50 h over zeolites and other solid acid catalysts. The kinetic dependencies of this reaction on temperature and reagent concentration, over the selected clays were also investigated. It was established that, in the temperature and reagent concentration regime studied, the reaction was first order with respect to α-pinene. The apparent activation energies over the two catalysts, calculated from Arrhenius plots, were almost identical at 72 kJ mol-

Robust lithium-ion anodes based on nanocomposites of iron oxide-carbon-silicate

Robust composite particles containing Fe3O4 cores and porous conductive carbon-silicate layers were synthesized using an aerosol-assisted process followed by vapor coating using organosilanol as the precursor. Such unique synthesis enables the composites with high capacity and good cycle performance, and can be extended towards other oxide composites for energy storage.close5