Tomas Bata University in Zlín
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Robust controller design with two-degree-of-freedom feedback loop factorization for oscillating plant with uncertain time delay
No full textApplication of Robust Control Toolbox for Time Delay Systems implemented in the Matlab system to the oscillating plant with uncertain time delay using the D-K iteration and algebraic approach. The algebraic approach combines the structured singular value, algebraic theory and algorithm of global optimization solving remaining issues in structured singular value framework. The algorithm of global optimization can be alternated with direct search methods such as Nelder-Mead simplex method giving solutions for problems with one local extreme. As a global optimization method, Differential Migration is used proved to be reliable in solving this type of problems. The D-K iteration represents a standard method in the structured singular value theory. The results obtained from the D-K iteration are compared with the algebraic approach.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (LO1303, MSMT-7778/ 2014
Communication system for sharing and providing information about threats and incidents on transport infrastructure elements
No full textTransport infrastructure currently faces many anthropogenic threats, resulting in an increasing number of security incidents. These are, for example, attacks with explosives or firearms in the premises of railway stations and connected transport infrastructures, e.g. in the premises of airports or bus terminals. For this reason, it is essential that the owners or operators of these transport infrastructure elements have an effective tool for the timely sharing and provision of information about threats and incidents on transport infrastructure elements. For this purpose, this article presents a list of the affected entities of the transport infrastructure and the content page of the information that should be shared and transmitted between these entities. The supporting part of the article is the design of the sharing process and providing information about threats/incidents and the design of a communication system and suitable technical means for sharing and providing information about threats.Ministerstvo Vnitra České Republiky, (VK01030014
Fuzzy multicriteria evaluation model of cross-border cooperation projects under resource curse conditions
No full textThe main goal of this study is to develop a fuzzy multicriteria evaluation model of heterogeneous cross-border cooperation projects to ensure sustainable development of neighbouring regions, taking into account the goals of the announced competition and the possibility of avoiding the resource curse. The model allows you to compare projects of cross-border cooperation of different categories, takes into account expert linguistic conclusions on projects, considers the compliance of the challenge project, moves from expert conclusions to quantitative assessments. At the output of the model, we have an aggregated quantitative assessment of the project and a ranking of cross-border projects is built for their selection and financing. The results of the study can be useful for managers of cross-border project tenders, with the aim of improving the validity of supporting decision-making and sustainable development of neighbouring regions through the prism of the curse, both natural and human resources.European Commission, EC; Univerzita Tomáše Bati ve Zlíně, (RO/FaME/2022/05
Fractional order PD controller design for third order plants including time delay
Get PDFDue to the lack of integral operator, proportional derivative controllers have difficulties in providing stability and robustness. This difficulty especially felt in higher order systems. In this publication, analytical design method of fractional proportional derivative controllers presented to ensure the stability of third order systems with time delay. In this method, it is aimed to achieve the frequency characteristics of standard control system to ensure stability. It is aimed to provide the desired gain crossover frequency, phase crossover frequency and phase margin properties of the system. In this way, the stability and robustness of the system can be obtained by choosing the appropriate values. The reason for choosing a fractional order controller is that the controller parameters to provide these features can be tuned more accurately. order for the obtained stability to be robust to unexpected external effects, it is aimed to flatten the system phase. In the literature, phase flattening is performed by setting the phase derivative to zero at specified frequency value. This can lead to mathematical complexity. this publication, the phase flattening process is provided graphically by correctly selecting the frequency characteristics given above. Thus, an accurate and reliable controller design method is presented, avoiding mathematical complexity. The effectiveness of the proposed method has been demonstrated on three different models selected from the literature. The positive contribution of the method to the system robustness has been proven by changing the system gain at certain rates
Evolution of the polyphenolic content of Moravian white grape variety wines of different vintages during storage
Get PDFWine is known as a source of bioactive compounds and is one of the alcoholic beverages with the highest phenolic content. There has been growing interest in the composition of wine due to its beneficial properties for human health. This work focuses on biologically active and sensory attributes of white wine and presents research on wine chemical profiles in relation to their geographical origin, varieties and storage. The aim of this study was to investigate the phenolic compound evolution of 35 selected white wine varieties from the Moravian region in the Czech Republic. To separate and identify individual phenolic compounds in the wines, the high-performance liquid chromatographic method was used. A spectrophotometric method was applied for the determination of total polyphenol and total flavonoid content. This research presents results for the total benzoic and cinnamic acid derivatives, flavonols, flavanols and stilbene content of Moravian white grape varieties. Differences were found in the content of these compounds, and the results show that the phenolic concentrations depend on grape variety and storage time.Tomas Bata University in Zlin, TBU, (IGA/FT/2023/003)project of the Internal Grant Agency of Tomas Bata University in Zlin [IGA/FT/2023/003
Further experimental results on modelling and algebraic control of a delayed looped heating-cooling process under uncertainties
Get PDFThe aim of this research is to revise and substantially extend experimental modelling and control of a looped heating-cooling laboratory process with long input-output and internal delays under uncertainties. This research follows and extends the authors' recent results. As several significant improvements regarding robust modelling and control have been reached, the obtained results are provided with a link and comparison to the previous findings. First, an infinite-dimensional model based on mathematical-physical heat and mass transfer principles is developed. All important heat-fluid transport and control-signal delays are considered when assembling the model structure and relations of quantities. Model parameter values optimization based on the measurement data follows. When determining static model parameter values, all variations in steady-state measured data are taken into account simultaneously, which enhances previously obtained models. Values of dynamic model parameters and delays are further obtained by least mean square optimization. This innovative model is compared to two recently developed process models and to the best-fit model that ignores the measured variations. Controller structures are designed using algebraic tools for all four models. The designed controllers are robust in the sense of robust stability and performance. Both concepts are rigorously assessed, and the obtained conditions serve for controller parameter tuning. Two different control systems are assumed: the standard closed-loop feedback loop and the two-feedback-controllers control system. Numerous experimental measurements for nominal conditions and selected perturbations are performed. Obtained results are further analyzed via several criteria on manipulated input and controlled temperature. The designed controllers are compared to the Smith predictor structure that is wellestablished for time-delay systems control. An essential drawback of the predictor regarding disturbance rejection is highlighted.College of Polytechnics Jihlava; National Foreign Expert Project, (G2022178023L); Tomas Bata University in Zlin, TBU; Grantová Agentura České Republiky, GA ČR, (GAČR 21–45465L)Czech Science Foundation [GAC?R 21-45465L]; National Foreign Expert Project [G2022178023L
Effect of fusion temperature on the crystallization kinetics of poly(butylene terephthalate)
No full textA tremendous effect of fusion temperature on the crystallization kinetics of poly(butylene terephthalate) (PBT) was discovered. The crystallization peak shifted by 22 °C towards lower temperatures, and the kinetics changed about ten times. Nonisothermal crystallization experiments revealed that an increase in fusion temperature led to a noticeable shift in the heat flow curve towards lower temperatures, indicating a significant change in the number of nucleation centres. This shift was observed within the temperature range of 232 °C to 246 °C, beyond which the heat flow curve stabilized. The analysis of relative crystallinity showed a decrease in crystallinity with increasing fusion temperature up to 246 °C, accompanied by a shift of the S-curve towards lower temperatures. Detailed analysis revealed that the peak position of the heat flow curve decreased significantly from 232 to 240 °C and then continued to decrease slightly until 246 °C, and then in the range 246-260 °C, it remained constant. The influence of cooling rate on relative crystallinity was also investigated, revealing that faster cooling rates shifted the relative crystallinity curve towards lower temperatures. The Ozawa model was linear and demonstrated the significant effect of the cooling rate (for 15, 20 and 25 °C min−1) on the nonisothermal crystallization kinetics. The Avrami model is perfectly implemented to evaluate the isothermal crystallization kinetics. Isothermal crystallization experiments confirmed the trends observed in the nonisothermal experiments, with the fastest crystallization occurring at lower fusion temperatures. During the isothermal crystallization experiment, the kinetics gradually decreased in the fusion temperature range 232-242 °C, and then in the range 242-250 °C, it remained constant. Overall, the study provides insights into the crystallization behaviour of PBT at different fusion temperatures and cooling rates.Tomas Bata University in Zlin, TBU, (IGA/FT/2023/008)University of Tomas Bata in Zlin [IGA/FT/2023/008
The moderating role of gamification toward intentions to use mobile payments applications in Bahrain: an integrated approach
Get PDFPurpose: Using an integrated theoretical model, this study aims to examine the moderating role of gamification in influencing intentions to use mobile payment applications in Bahrain.
Design/methodology/approach: The current examination happens to be the first approximation in the context of Bahrain wherein an extended TPB-based model integrating variables from TAM and UTAUT2 is used along with gamification and situational influence to examine the intentions to use m-payment applications.
Findings: The findings revealed that among the variates of the TPB, AT and PB significantly affect the intentions (IN) to use m-payment applications in Bahrain, but SN fails to affect intentions, similarly SI also fails to affect intentions thereby proving that the pandemic fails to drive the intention of the population under study toward using m-payment applications. However, when the application offers gamification (GM) features, SI significantly affects intentions through GM, thus experience along with situation drives intentions and this becomes the major theoretical contribution of the study.
Practical implications: This examination offers useful practical implications in the form of the findings revealing that GM affects intentions to use m-payment applications and that GM moderates the relationship between perceived risk (PR) and IN, as well as SI and IN, which can be used by the service providers to improve the user experience and achieve better acceptance of their application.
Originality/value: The novelty of the study lies in testing the integrated theoretical model in the context of a GCC nation, Bahrain
Job insecurity across various occupation in Czech Republic
Get PDFJob security for most working population is crucial in ensuring living standards. The main goal of this article is to find out, based on the analysis of employment, unemployment, vacancies, and wages in various job categories in the Czech Republic between 2015 and 2022, which job groups are most prone to job insecurity and job loss. Data from the Information System on Average Earnings (ISPV) and MLSA portal were used to analyse the structure of job seekers and job vacancies and to establish employment and wages. Data were processed using descriptive statistical methods. An evaluation of the variance was performed among the selected variables. A t-test was used to measure differences in job security between the observed employment categories. The results show that higher-skilled worker requirements characterize the best job classes regarding job security and wages. On the other hand, the unstable job categories with high unemployment rates and low wage rates were support and unqualified jobs and service and sales jobs. A final important finding is that firms are creating jobs with low educational requirements, which may indicate stagnation in future job innovation.Tomas Bata University in Zlin [IGA/FaME/2022/007
Information ecology, problems and negative impacts in the context of information technologies
No full textInformation ecology is the presentation of a middle way between theories of the influence of new technologies on human life and culture. We know from practice that technology is either taken as the salvation of humanity or as a tool to exterminate life on planet Earth. The article primarily presents the relatively unknown concept of information ecology, aiming to define the idea of information ecology in modern information science. It also describes other closely related concepts of digital well-being and digital ecology. Information ecology wants to teach us to use, but not abuse, technical inventions. Although we are partly dependent on technology, we must not let this dependence grow unhealthy. Theoretically, the article analyzes the main problems of the information environment and discusses the consequences of informationally 'unhealthy' behavior