Complexity of testing morphic primitivity

We analyze the algorithm in [Holub, 2009], which decides whether a given word is a fixed point of a nontrivial morphism. We show that it can be implemented to have complexity in O(mn), where n is the length of the word and m the size of the alphabet

Establishment of the Linux internet gateway using advanced filtering

Práce Realizace internetové brány na Linuxu s pokročilým filtrováním se soustřeďuje na~instalaci operačního systému Linux na~starší počítače, který plní funkci jako brána pro připojení klientů ve~vnitřní síti do internetu. V práci je uveden popis vytvoření pokročilého filtrování s~pomocí iptables. Ukazuje některé typy bezpečnosti proti útokům z Internetu. V~dalších kapitolách jsou probrány pokročilé mechanismy řízení provozu (jako tc a qdisc). Tento systém front se ukazuje jako velice přínosný všude tam, kde je potřeba hierarchicky dělit provoz mezi uživatele. Jsou popsány typy front a~sestavena konfigurace pro klienty ve vnitřní síti. Dále je uvedeno použití dns serveru typu caching-only a také aplikace denyhosts, která zvyšuje celkovou bezpecnost systému. Mít vlastní DNS server se osvědčuje, zejména pokud chceme snížit datový provoz. Poslední kapitola se zabývá radius serverem a jeho implementací s použitím apache a databáze mysql. Popsány jsou možnosti některých konfiguračních voleb jednotlivých služeb a také uvedeny příklady konfigurací. Nakonec je předveden systém pro autentizaci uživatelů skrze RADIUS server. Celá práce se snaží poskytnout komplexní pohled na problematiku bezpečnosti a~filtrování.The thesis Establishment of the Linux internet gateway using advanced filtering focuses on~the installation of~the Linux operating system on~the older computers, that functions as a gateway to connect clients in the internal network to the Internet. The thesis describes creation an advanced filter with using iptables. Shows some types of security against attacks from the Internet. The other chapters are discussed, advanced traffic control mechanism (such as a TC and a qdisc). The system queue, it is highly beneficial where it is necessary to hierarchically divide traffic between users. It describes types of queue and assembled configurations for clients in the internal network. Next chapter describes the DNS server caching-only type and application denyhosts, which increases the overall security system. Have your own DNS server is certified, especially if we want to reduce the data traffic. Last chapter describes the RADIUS server and its implementation using Apache and MySQL database. Furthermore, the configuration options are described and the examples of the particular configurations are provided. Finally, it presented a system for authentication through the RADIUS server. The thesis seeks to provide a~complex view of security and filtering.

The present SP tests for determining the transition temperature TSP on "U" notch disc specimens

The principal difference between the small punch (SP) testing technique and standardized impact testing lies in the fact that the SP tests carried out in accordance with CWA 15627 Small Punch Test Method for Metallic Materials use disc-shaped test specimens without a notch. Especially in tough materials, the temperature dependence of SP fracture energy ESP in the transition area is very steep and lies close to the temperature of liquid nitrogen. In this case, the determination of SP transition temperature TSP can lead to significant errors in its determination. Efforts to move the transition area of penetration testing closer to the transition area of standardized impact tests led to the proposal of the notched disc specimen 8 mm in diameter and 0.5 mm in thickness with a "U" shaped notch 0.2 mm deep in the axis plane of the disc. The paper summarizes the results obtained to date when determining the transition temperature of SP tests TSP, determined according to CWA 15627 for material of pipes made of P92, P22, and a heat treated 14MoV6-3 steel in the as delivered state. Although the results obtained confirmed the results of other works in that the presence of a notch in a SP disc is insufficient to increase the transition temperature significantly and certainly not to the values obtained by Charpy testing, comparison of the different behaviors of the alloys tested reveals some evidence that the notch reduces the energy for initiation. This implies that the test on a notched disc is more a test of crack growth and would be a useful instrument if included in the forthcoming EU standard for SP testing.Web of Science105art. no. 49

Evaluation of Nuclear Fuel Safety and Reliability Using Research Reactors' In-Core Experiments

Cílem této práce je ukázat vztah mezi bezpečností jaderného paliva, experimenty ve výzkumných reaktorech a výpočetními kódy. Práce je zaměřena na výpočetní kód Transuranus. V práci jsou představeny čtyři experimenty, které byly modelovány v kódu Transuranus. Hlavní důraz je kladen na uvolnění plynných produktů štěpení, prodloužení palivového sloupce a změnu vnějšího průměru pokrytí. Z výsledků je možné stanovit rozdíly mezi verzemi Transuranu v1m1j09 a v1m3j12 a také vliv vybraných parametrů vstupního souboru kódu Transuranus na výsledky, tak že práce přinese poznatky k možnému vylepšení výpočtu bezpečnostní analýzy palivové vsázky počítané kódem Transuranus.The aim of this master thesis is to show a connection among nuclear fuel safety, experiments led in research reactors and calculation codes. This thesis focuses on the calculation code Transuranus. There are represented four experiments, which were calculated in Transuranus. The fission gas release, elongation and growth of fuel were particularly monitored. Is is possible to set differences among versions v1m1j09 and v1m3j12 from achieved results, as well as the influence of selected Transuranus parameters on the results, so the thesis may bring new pieces of knowledge for improvement of safety analysis calculation by Transuranus.

Short-term Response of Soil Iron to Nitrate Addition

The inhibition of soil Fe(III) reduction by fertilizer NO3 − applications is complex and not completely understood. This inhibition is important to study because of the potential impact on soil physicochemical properties. We investigated the effect of adding NO3 − to a moderately well-drained agricultural soil (Sadler silt loam) under Fe(III)-reducing (anoxic) conditions. Stirred-batch experiments were conducted where NO3 − was added (0.05 and 1 mM) to anoxic slurries and changes in dissolved Fe(II) and Fe(III), oxalate-extractable Fe(II), and dissolved NO3 − were monitored as a function of time. Addition of 1 mM NO3 − inhibited Fe(II) production sharply with reaction time, from 10% after 1 h to 85% after 24 h. The duration of inhibition in Fe(II) production was closely related to the presence of available NO3 −, suggesting preferential use of NO3 − by nitrate reductase enzyme. Active nitrate reductase was confirmed by the fivefold decline in NO3 − reduction rates in the presence of tungstate (WO4 2−), a well-known inhibitor of nitrate reductase. In addition, NO3 −–dependent Fe(II) oxidation was observed to contribute to the inhibition in Fe(II) production. This finding was attributed to a combination of chemical reoxidation of Fe(II) by NO2 −– and NO3 −–dependent Fe(II) oxidation by autotrophic bacteria. These two processes became more important at a greater initial oxalate-Fe(II)/NO3 − concentration ratio. The inhibitory effects in Fe(II) production were short-term in the sense that once NO3 − was depleted, Fe(II) production resumed. These results underscore the complexity of the coupled N–Fe redox system in soils

Identifying and Correcting Iron Deficiency in Field Crops.

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Automatic Segmentation of Cardiac Tissue Movement from ECG Record

Tato práce se zabývá automatickou segmentací periodického pohybu srdečního svalstva v EKG záznamu. Popisuje návrh a implementaci aplikace, jenž automaticky segmentuje EKG záznam na jednotlivé srdeční stahy. EKG záznam je uložen samostatně nebo je součástí videozáznamu. Tyto vstupní data jsou uložena v souborech ve formátu HDF nebo DICOM.This thesis deals with the automatic segmentation of the cardiac tissue movement from ECG record. It describes the design and implementation of application that automatically segments the record into individual ECG heart contractions. ECG record is stored separately or is included in the video. These input data are stored in files in the DICOM format or in the HDF format.