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Measuring the Parameters of Piezo Energy Harvesters
Kunz, Jan ; Novák,, Martin (referee) ; Hadaš, Zdeněk (referee) ; Beneš, Petr (advisor)
This dissertation deals with the measurement of piezoenergy harvester parameters, in particular the measurement of their efficiency. The first part of the thesis summarizes important metrics for their comparison and reviews existing measurement systems for measuring harvester performance parameters. The measurement of harvester efficiency is simplified due to the complexity of power measurement and harvester efficiency is calculated from its parameters. However, this method is not accurate because it neglects mechanical losses and has a large measurement uncertainty. For this reason, the main objective of this work is to find a way to directly measure the harvester power input and thus measure its efficiency by definition, i.e. including mechanical losses. By analyzing the power flow in the harvester power chain, a way to achieve this goal has been found. Then, I have created an automated measurement system that allows to measure the harvester power parameters and also its efficiency including the determination of measurement uncertainties. In the last section, the performance, parameters and especially the two types of efficiency for commercially available harvesters are compared. As expected, the efficiency evaluated according to the definition come out smaller than in the case of its simplified version. However, this ratio varies widely for different harvester types, with the new efficiency being approximately one-third for PZT harvesters but only one-hundredth for PVDF harvesters. This significant difference shows that the different types of harvesters have large differences in mechanical losses, this difference could not be measured until now and thus remained neglected.
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Comparison of integrated circuits for management of single cell Li-ion battery
Novák, Štěpán ; Burian, František (referee) ; Kunz, Jan (advisor)
Lithium-ion batteries are now widely used as power sources for mobile devices, electric vehicles, consumer electronics and other applications. For proper operation and extended service life of Li-ion batteries, it is important that the parameters specified by the manufacturer are met. This is ensured by means of appropriate circuits, the accuracy of which is the focus of this paper. This work provides an overview and comparison of different types of circuits for Li-ion battery management and charging and explains the basic principles of their operation.
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Mapování a zvýšení efektivity výrobních procesů v podniku
Dobešová, Bohdana
This master’s thesis deals with mapping and measuring manufacturing processes in a selected business. Theoretical part explains basic terms from area of manufacturing processes, describes performance measurement methods and risks possibly affecting the efficiency of the whole process. Practical part maps and measures manufacturing processes in the selected business. Based on the measurement results, the riskiest processes are evaluated, and possible efficiency improvements are drawn up. Manufacturing processes are graphically presented in process model schemes.
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Measuring the Parameters of Piezo Energy Harvesters
Kunz, Jan ; Novák,, Martin (referee) ; Hadaš, Zdeněk (referee) ; Beneš, Petr (advisor)
This dissertation deals with the measurement of piezoenergy harvester parameters, in particular the measurement of their efficiency. The first part of the thesis summarizes important metrics for their comparison and reviews existing measurement systems for measuring harvester performance parameters. The measurement of harvester efficiency is simplified due to the complexity of power measurement and harvester efficiency is calculated from its parameters. However, this method is not accurate because it neglects mechanical losses and has a large measurement uncertainty. For this reason, the main objective of this work is to find a way to directly measure the harvester power input and thus measure its efficiency by definition, i.e. including mechanical losses. By analyzing the power flow in the harvester power chain, a way to achieve this goal has been found. Then, I have created an automated measurement system that allows to measure the harvester power parameters and also its efficiency including the determination of measurement uncertainties. In the last section, the performance, parameters and especially the two types of efficiency for commercially available harvesters are compared. As expected, the efficiency evaluated according to the definition come out smaller than in the case of its simplified version. However, this ratio varies widely for different harvester types, with the new efficiency being approximately one-third for PZT harvesters but only one-hundredth for PVDF harvesters. This significant difference shows that the different types of harvesters have large differences in mechanical losses, this difference could not be measured until now and thus remained neglected.
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Analysis of ways improving efficiency in the public sector by using example of a semi-budgetary organization Czech Geological Survey.
Horáková, Lucie ; Peková, Jitka (advisor) ; Matula, Miloš (referee)
This paper is focused on evaluation and improvement of the allocative efficiency of the public sector. The introductory chapters give us information about the necessity of existence, operation and financing of the public sector and its representation in public finances. Rules for establishing, financing and management of semi-budgetary organizations are discused in a more elaborated manner. The theoretical part explains the concept of efficiency and provides a detailed overview of methods of measuring the efficiency in the public sector by various authors. In the practical part, the theoretical approaches are demonstrated on the example of the Czech Geological Survey (ČGS). ČGS is a semi- budgetary organization established by the Ministry of the Environment, but partly also works as a research organization. Also there are given the competences and organizer's requirements. Financing of the organization is provided from several sources, whereas the contribution from the organizers part is reduced on a year to year basis and the organization is forced to cover the loss by research activities and providing services to foreign customers. The effectiveness analysis is based on the concept of Sintonen. However it is complicated by the fact that ČGS is on one hand A semi-budgetary organization and on the other A research organization. For the semi-budgetary organizationS the appropriate approach is to minimize costs, but for the research organization it is rather about increasing revenues. For the highest efficiency possible it is necessary to find a combination of both approaches.
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Efficiency of recruiting employees for ExxonMobil
Janečková, Radka ; Dvořáková, Zuzana (advisor) ; Cetkovský, Pavel (referee)
The thesis focuses on the evaluation of the efficiency of recruiting employees in ExxonMobil Corporation. The main aim is to evaluate methods that are used to reach MPT Experienced hires. The theoretical part describes the recruitment process and the traditional and modern methods of attraction. The practical part introduces the reader to the situation on the labour market in the petrochemical industry, presents ExxonMobil Corporation and evaluates methods of attraction, which are used in six selected states of the European Union for filling positions with MPT experienced hires. In the end the ideas that could contribute to the development of regional sourcing strategy of MPT experienced hires will be suggested.
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Efficiency of recruiting and selection of the employees
Skrášková, Monika ; Dvořáková, Zuzana (advisor) ; Černý, Leoš (referee)
The thesis focuses on efficiency method measurement in the process of recruiting and selection of the employees. The main goal of the thesis is to describe the options and to measure the efficiency of recruiting and selection of the employees. The theoretical part of the work focuses on methods of the recruitment and describes efficiency measurement of recruitment. The part two focuses on certain efficiency of e - recruitment in different business companies and evaluates the influence of the HR information systems on recruitment efficiency.
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