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Analysis of Selected Artefacts in Diffusion-Based Magnetic Resonance Measurements
Marcoň, Petr ; Král, Bohumil (referee) ; Frollo, Ivan (referee) ; Bartušek, Karel (advisor)
The presented dissertation thesis analyses artefacts in diffusion-weighted images. In medical practice, the artefacts can impede the diagnostics of pathological tissues and, therefore, need to be eliminated. As the first step within the thesis, an analysis of the most frequent artefacts in diffusion-weighted images is performed, and the hitherto known approaches to artefact elimination are described. In order to facilitate the reduction of artefacts caused by the inhomogeneity of the static magnetic field and induced by eddy currents, a novel three-measurement method is shown. This technique will find application especially in measuring the diffusion coefficient of isotropic materials. At this point, it is important to note that a significant and commonly found problem is the magnetic susceptibility artefact; different magnetic susceptibility values at the boundary between two materials can cause magnetic field inhomogeneities and even complete loss of the signal. Therefore, we designed a novel method for the measurement of magnetic susceptibility in various samples of magnetically incompatible materials, which do not produce any MR signal. The technique was experimentally verified using a set of differently shaped diamagnetic and paramagnetic samples. In addition to the magnetic susceptibility problem, the thesis presents artefacts such as noise, motion-induced items, hardware limitations, chemical shift, and the dependence of the diffusion coefficient on the temperature. To enable precise measurement of the diffusion coefficient, we proposed a thermal system; in the experiment, it was determined that when the measurement error does not exceed 5%, the temperature change should not be higher than 0,1 °C. In the final sections of the thesis, practical application examples involving the designed methods are shown.
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New Optimization Algorithms for a Digital Image Reconstruction in EIT
Kříž, Tomáš ; Koňas, Petr (referee) ; Král, Bohumil (referee) ; Dědková, Jarmila (advisor)
This doctoral thesis proposes a new algorithm for the reconstruction of impedance images in monitored objects. The algorithm eliminates the spatial resolution problems present in existing reconstruction methods, and, with respect to the monitored objects, it exploits both the partial knowledge of configuration and the material composition. The discussed novel method is designed to recognize certain significant fields of interest, such as material defects or blood clots and tumors in biological images. The actual reconstruction process comprises two phases; while the former stage is focused on industry-related images, with the aim to detect defects in conductive materials, the latter one concentrates on biomedical applications. The thesis also presents a description of the numerical model used to test the algorithm. The testing procedure was centred on the resulting impedivity value, influence of the regularization parameter, initial value of the numerical model impedivity, and effect exerted by noise on the voltage electrodes upon the overall reconstruction results. Another issue analyzed herein is the possibility of reconstructing impedance images from components of the magnetic flux density measured outside the investigated object. The given magnetic field is generated by a current passing through the object. The created algorithm for the reconstruction of impedance images is modeled on the proposed algorithm for EIT-based reconstruction of impedance images from voltage. The algoritm was tested for stability, influence of the regularization parameter, and initial conductivity. From the general perspective, the thesis describes the methodology for both magnetic field measurement via NMR and processing of the obtained data.
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STUDY OF CHANGES OF BIOLOGICAL MATERIAL CHARACTERISTICS IN ELECTROMAGNETIC FIELDS
Vlachová Hutová, Eliška ; Král, Bohumil (referee) ; Kolářová, Jana (referee) ; Bartušek, Karel (advisor)
Presented dissertation discusses the influence of electromagnetic fields on the weight of the particles, which are considered in this work as substances with the hub. Theoretical knowledge was practically tested on plant organisms (early somatic embryos, fungal pathogens), theoretically the influence of electromagnetic field on cell structure was modeled. It was subsequently confirmed by a practical experiment assumption about the influence of electromagnetic fields on the weight of the particles. These experiments were preceded by a theoretical study of the problem and the formulation of a solution using Maxwell's equations, from which other descriptive equations and formulas were derived. The results of the experiments were presented at several professional conferences and published in professional journals and proceedings.
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Designing a controlling concept using the business intelligence system
Hejdánek, Michal ; Král, Bohumil (advisor) ; Houser, Václav (referee)
The Master Thesis deals with the use of the controlling concept in business management, Business Intelligence systems and their interconnection. The aim is to propose this integration link on the example of a particular company and at the same time to give management recommendations in areas that will be evaluated in the analysis as insufficient. The theoretical part of this thesis is divided into three main chapters. The first deals with the definition of controlling, its tools and organizations. The second one describes business intelligence, not just the basic principles of this technology, but also the choice of tools and the implementation process are explained. The following chapter lists two software tools that combine controlling and business intelligence in practice. The practical part is divided into a general description of the company, analysis of the applied elements of controlling and then the proposal of solution of insufficient areas and the process of BI implementation, which contains 12 steps which would enable to implement the BI concept.
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Design of multidimensional performance measurement system
Piechaczek, Petr ; Menšík, Michal (advisor) ; Král, Bohumil (referee)
The thesis deals with the design of multidimensional performance measurement system. The aim of the thesis is to propose a multidimensional performance measurement system for the company providing services in recruiting new employees. The performance measurement system is based on the Balanced Scorecard. The thesis is divided into two parts. The first one is about theoretical basis for design the multidimensional performance measurement system, the second one deals with the proposal of this system for the company PŘEDVÝBĚR.CZ s.r.o. Firstly, the enterprise is introduced from the point of view of basic information, provided services, organizational structure, target market segments, and competitors. Following this information, a SWOT analysis of the company is made. This is the basis for the company´s strategy. Then, a strategy map is created. It captures the key causal relationships in the company. After the strategy map, a performance measurement system is designed into four perspectives of the Balanced Scorecard.
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Financial responsibility management of divisionalized companies
Navrátil, Jakub ; Wagner, Jaroslav (advisor) ; Král, Bohumil (referee)
An opening part of the thesis explains the role of responsibility accounting within overall management control system of a company. Individual chapters are focused on the key specific aspects of businesses with a divisionalized organizational structure. A description of principal characteristics related to this type of an organizational structure is followed by a detailed explanation of various types of responsibility centers. A subsequent chapter deals with bookkeeping aspects of responsibility accounting as well as with transfer prices. A theoretical part is concluded after a comprehensive analysis of a characteristic features related to responsibility centers' financial management on different levels of a corporate's hierarchy. An application part of the thesis is based on an assessment of responsibility accounting environment within a chosen responsibility center inside a real divisionalized corporation.
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Customer Profitability Analysis in the Service Industry
Kushnarevich, Olga ; Matyáš, Ondřej (advisor) ; Král, Bohumil (referee)
"Customer Profitability Analysis in the Service Industry" aims to describe the practical application of customer profitability analysis techniques in holding XYZ, which provides ICT services to the hospitality industry. The thesis starts with a theoretical part. It describes several management accounting techniques for measuring customer profitability. The second part of the thesis demonstrates the application of some of these techniques in a real-life environment. Implementing management accounting tools, business processes and changing the accounting data structure are described step by step.
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Comparison of the Management Accounting and Controlling Practices in the People’s Republic of China and Germany
Häuser, Florian ; Wagner, Jaroslav (advisor) ; Král, Bohumil (referee)
This master thesis compares management accounting (MA) in China and Germany. It starts by analyzing the conceptual development over time. Afterwards, it categorizes the spread of the methods and explains conceptual differences in more detail. Subsequently, macroeconomic factors that have influenced the development of MA are described, evaluated, and future implications for the further development of MA are derived. For this purpose a traditional literature review is used. The MA practice in Germany is further disseminated than in China. Moreover, German management accountants are characterized as business partners while Chinese management accountants are perceived as analysts and inspectors. Other conceptual differences in terms of MA are the data source, the overall orientation, country-specific techniques, and the organizational structure. Most of the differences between German and Chinese MA can be allocated to political, economic, foreign, educational, academic, and cultural influences. The future implications for the further development depend on each factor individually.
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Optimization of the experimental NQR spectrometer
Segiňák, Ján ; Král, Bohumil (referee) ; Steinbauer, Miloslav (advisor)
The thesis deals with the NQR spectroscopy, which is one of the modern non-destructive measurement and diagnostic methods for the characterization of various materials. It is using a quadrupole moment - a property of atomic nuclei of certain isotopes. A method of nuclear quadrupole resonance (NQR) is in principle very similar to nuclear magnetic resonance (NMR). Thesis in the theoretical part analyse the principles of NMR and NQR, describes the possible use of this method to detect for example explosives, drugs, and other chemicals. In the following chapters are analysed the key parameters of NQR spectrometer and the principle of the chosen measurement method. The practical part deals with the individual components of NQR spectrometer, the design of possible improvements and programming of the measuring sequence. In the final chapter are processed the measurements of the submitted samples.
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Partial Discharges Detection and Spatial Localization in High Power Transformers Using UHF Method
Čáp, Martin ; Král, Bohumil (referee) ; Zemánek,, Ivan (referee) ; Drexler, Petr (advisor)
The thesis discusses the design and experimental verification of a new method for detecting partial discharges in oil-cooled high-power transformers, emphasizing the origin of the measured signal from the outer and inner regions of the transformer tank. The detection and spatial localization of partial discharges utilizes UHF (Ultra High Frequency) electromagnetic signal measurement. The UHF partial discharge detection method, also referred as UHF PD, is one of the most advanced techniques for the accurate spatial localization of the signal source position. The focus of the thesis lies in the development of technical and software solutions for the separation of partial discharge signals originating from the internal space of the transformer and the spurious signals from the connection lines. The proposed technical and program solutions constitute a signal discriminatory method. The precise and repeatable diagnostics of the transformer state are guaranteed by observing the measurement methodology and special setting of the diagnostic system. The functionality of the signal discriminatory method was verified during real measurement of the oil-cooled power transformers at the Dukovany nuclear power plant in operation. The output of the designed methodology is to set up a calibration procedure and follow-up steps to ensure objective, repeatable, and comparable measurements for the purposes of regular predictive maintenance in transformers.
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