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The diploma thesis named Continuous monitoring of a machine tool wear deals with the issue of tool wear of machining. The thesis is divided into segments and the first segment deals with the areas of tool wear, the specific trends in the field of eliminating the tool wear and prolonging durability of tools, non-destructive test methods. These segments are a critical parts of the research, in the following part concentrates on the testing performed by the method of acoustic emission. The last part concentrates on the critical evaluation of the testing results.

We investigate possible usage of Errors-in-Variables estimator (EIV), when esti- mating structural equations models (SEM). Structural equations modelling pro- vides framework for analysing complex relations among set of random variables where for example the response variable in one equation plays role of the predic- tor in another equation. First an overview of SEM and some common covariance based estimators is provided. Special case of linear regression model is investi- gated, showing that the covariance based estimators yield the same results as ordinary least squares. A compact review of EIV models follows, Errors-in-Variables models are re- gression models where not only response but also predictors are assumed to be measured with an error. Main contribution of this paper then lies in defining modifications of the EIV estimator to fit in the SEM framework. General opti- mization problem to estimate the parameters of structural equations model with errors-in-variables si postulated. Several modifications of two stage least squares are also proposed for future research. Equation-wise Errors-in-Variables estimator is proposed to estimate the coeffi- cients of structural equations model. The coefficients of every structural equation are estimated separately using EIV estimator. Some theoretical conditions...

Monte Carlo simulation methods are very universal tool, which is applicable in many different cases. Major part of this work is devoted to variance reduction techniques and other improvements of Monte Carlo estimate. Practical examples of financial derivative pricing will be shown. 1

The subject of diploma thesis is the pension system in the Czech Republic. We warn about the deficit increase in the future and suggest taking the number of children raised into consideration in the pension system construction. Pension system in the Czech Republic is described in detail. The first "pay-as-you-go" pillar represents the main part of the system. It could bring financial problems (if the retirement pension and pension income tax will stay at the same level as now) considering the expected trends in demography. Population projection was calculated using cohort component method (including migration). The threshold for the projection is year 2011, projection is calculated with 100-year horizon. There were also calculated revenues and expenses of the pension system for each projected year. If the expected parameters of the projection will be realized, the deficit of pension system in the hundred year period will reach 9.5 billion Kč (prices 2011). It represents the deficit 95.3 milliard Kč each year in the average. To reduce the deficit it is possible to increase the pension tax paid by productive people. But it could also bring the decline of fertility, because lower income could make people decide to reduce number of children. It would deepen the problems in the pay-as-you-go system. The financial problem of pension system could be solved by taking the number of children raised into consideration of the pension system construction. It would eliminate the situation that it is economically more favourable to be childless during the life. It could also bring the fertility increase. In the diploma thesis the value of the deficit is simulated for the various parameters of pension system and for the various demographic development in the future.

Příspěvek představuje numerickou analýzu průběhu porušení těles zatěžovaných v modifikované zkušební konfiguraci testu excentrickým tahem (Compact Tension test, CT), plánovaných pro použití při zjišťování lomových parametrů kvazikřehkých materiálů na bázi cementu, a to včetně rozsahu lomové procesní zóny. Série těles zahrnující tři velikosti, určená pro experimenty za využití rentgenografie, byla modelována v programu ATENA 2D. Zváženy byly různé varianty excentricity tahové síly, jejího vnesení do tělesa a délek iniciačního zářezu pro optimalizaci počtu náročných experimentů. The paper introduces a numerical analysis of failure process in specimens loaded in modified Compact Tension (CT) test configuration which are intended to be used for estimation of fracture parameters of quasi-brittle cement-based materials, including the extent of the fracture process zone. Specimen set (consisting of three sizes), designated to future testing in lab by X-ray imaging, was modelled in ATENA 2D software. Several variants of the tensile load eccentricity, the way of the load application and the initial crack length were considered in order to optimize the range of demanding experiments.

Different formats of PCAP (Packet CAPtures) files are nowadays widely used for storing computer network communications. This paper outlines information about PCAP formats with focus on packets precise timing and order. In thjs paper we compare capabilities of different open-source tools for handling PCAP files and introduce our own tool for merging multiple PCAPs. Finally, we evaluate the performance of the implemented tool and compare it with existing implementations.

Příspěvek se zabývá analýzou polí napětí a deformací v tělese s trhlinou. Záměrem autorů je určení dostačujícího počtu členů Williamsova mocninného rozvoje pro přesnou aproximaci těchto polí v okolí vrcholu trhliny, využitelnou dále např. pro odhad rozsahu lomové procesní zóny v kvazikřehkých materiálech. Hodnoty koeficientů těchto členů jsou určovány regresí z výsledků numerických simulací; jsou vyjádřeny jako funkce relativní délky trhliny. Řešeným případem je lomový test štípání klínem upraveného standardního krychlového tělesa pro zkoušení cementových kompozitů; numerická studie je provedena v MKP výpočetním systému ANSYS. The paper deals with an analysis of the stress and displacement fields in a cracked body. The intention of the authors is to determine the sufficient number of terms of the Williams power series for an accurate approximation of the near-crack-tip fields which can be subsequently used e.g. for estimation of the extent of the fracture process zone in quasi-brittle materials. Values of coefficients of these terms are determined via regression from results of numerical simulations; the coefficients are expressed as functions of the relative crack length. The analysis is conducted on a 2D numerical model of the wedge-splitting test on a modified standard cube-shaped specimen used commonly for testing of cementitious composites; ANSYS FE computational system is employed.

V příspěvku se sleduje iniciace lomu kvazikřehkého materiálu při simulovaném štípacím testu krychle s proměnnou relativní délkou zářezu. K numerické simulaci testu se využilo softwaru metody konečných prvků ATENA; byly tak získány diagramy zatížení vs. otevření ústí trhliny, které posloužily k průzkumu a ověření funkčnosti lomového modelu „dvojí K“. Pomocí tohoto modelu byly stanoveny hodnoty kohezivní a následně iniciační složky lomové houževnatosti, což v uvažovaném materiálu umožňuje kvantifikovat úroveň iniciace/propagace trhliny. Fracture initiation in quasi-brittle material during a simulated wedge splitting testing of a cube-shaped specimen with different relative notch lengths is presented in this paper. The numerical simulation of the test was performed using the ATENA finite element method software. Thus, load vs. crack mouth opening diagrams were obtained, which served to verify the functionality of the double-K fracture model. Using this model, the values of the initiation and cohesive components of fracture toughness were determined, allowing description of the level of crack initiation/propagation in quasi-brittle material.

Bachelor thesis describes differences and similarities in the demographic development between the Czech Republic and Sweden. The first part is focused on the systems of family policy in both countries. In the Czech Republic the main tool is the financial support for families with children. In Sweden the main aim is to provide mothers opportunities for both child care and their profession. In the next part it is written down the development of demographical indicators in the last 20 years. In the Czech Republic there is obvious the aging of population, while in Sweden the aging is not so strong. In the last 20 years the value of total fertility rate dropped at first, but later it rose again. In both countries women postpone childbearing into their higher ages. After standardization it's obvious that mortality in Sweden is much lower than in the Czech Republic. Life expectancy is rising in both countries. Both countries belong to the top of the world according to infant and neonatal mortality. Due to the decline in number of marriages after the year 1990 in the Czech Republic nowadays the marriage rate is at the similar level as in Sweden. Migration increase is quite variable, but both countries show permanently positive values. Both countries are compared according to the proportion of social protection expenditures on GDP or according to the total tax rate. In both indicators Sweden belongs to the countries with the highest level in Europe. At the end of the thesis the relationship between social policy and development of demographic indicators (especially birth rate) is shown. For the Czech Republic it's recommended to increase the number of nursery schools and to support part-time job.

The paper outlines a technique for estimation of the size and shape of an inelastic zone evolving around a crack tip during the tensile failure of structures/structural members made of quasi-brittle building materials, particularly cementitious composites. The technique is based on an amalgamation of several concepts dealing with the failure of structural materials, i.e. multi-parameter linear elastic fracture mechanics, classical non-linear fracture models for concrete (equivalent elastic crack and cohesive crack models), and the plasticity approach. The benefit of this technique is expected to be seen in the field of the determination of fracture characteristics describing the tensile failure of quasi-brittle silicate-based composites. The method is demonstrated using an example of a (numerically simulated) fracture test involving the three-point bending of a notched beam and validated by experimentally obtained results of three-point bending and wedge-splitting tests taken from the literature.

The paper is focused on a detailed numerical analysis of the stress field in specimens used for the wedge splitting test (WST) which is an alternative to the classical fracture tests (bending, tensile) within the fracture mechanics of quasi-brittle building materials, particularly cementitious composites. The near-crack-tip stress field in the WST specimen is described by means of constraint-based two-parameter fracturemechanics in the paper. Different levels of constraint in the vicinity of the crack tip during fracture process through the specimen ligament are characterized by means of the T -stress. Two basic shapes ofWST specimen – the cube-shaped and the cylinder-shaped one – are investigated and the determined near-crack-tip stress field parameters are compared to those of compact tension (CT) specimens according to the ASTM standard for classical and round geometry. Particular attention is paid to the effect of the compressive component of the loading force (complementing the splitting force) acting on the loaded side of the specimen and its reaction from the opposite part of the specimen on the stress field in the cracked body. Several variants of boundary conditions on the bottom side of the specimen used for this kind of testing procedure are also considered. The problem is solved numerically by means of the finite element method and results are compared with data taken from the literature.

Values of fracture parameters of quasi-brittle building materials are usually determined from results of tests performed on notched testing specimens. The contribution deals with the influence of various shapes of tips of notches prepared by a diamond saw in three point bending (3PB) specimens. The influence of the notch tip shape on the applied force corresponding to a failure initiation at the notch tip and also on the critical applied force appropriate to the maximal load-bearing capacity of the specimen is studied. Calculations are performed in two finite element method (FEM) systems (ATENA, ANSYS) based on two different approaches to fracture description (Cohesive crack models and LEFM, respectively). The numerical results obtained by both FEM systems are compared. The influence of notch shapes and width is quantified.