Katarína Žáková

Dr. Katarína Žáková

Slovak University of Technology in Bratislava
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Research Focus & Metrics

Academic Career Length

30Years (1997-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 November 2024 in Education and Information Technologies
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KŽKatarína Žáková
Katarína Žáková
Diana UrbanoDiana Urbano
Diana Urbano
RCRicardo João Cruz-Correia
Ricardo João Cruz-Correia
José Luis GuzmánJosé Luis Guzmán
José Luis Guzmán
JMJakub Matišák
Jakub Matišák
Understanding how students interact with AI bots is a first step towards integrating them into instructional design. In this report, the results of a survey conducted in three European higher education institutions, and in the context of four different areas are presented. Among other things, they reveal for what purposes students use ChatGPT, whether they trust and feel satisfied with the interaction, how they perceive ChatGPT as a tool to support learning, and if they intend to use it in the future. The study compares results across groups by analyzing data obtained from convenience samples, which include participants of three European countries, with diverse backgrounds, varying technology and science-related fields, as well as academic program levels. Students’ opinions regarding the utilization of ChatGPT in assessments are also documented, along with their perspectives on the potential future applications of these AI tools. The authors, teaching different subjects at different levels of higher education programs, describe their views on integrating ChatGPT and similar AI bots into instructional design.

4 November 2021 in Applied Sciences
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ŠCŠtefan Chamraz
Štefan Chamraz
MHMikuláš Huba
Mikuláš Huba
KŽKatarína Žáková
Katarína Žáková
This paper contributes toward research on the control of the magnetic levitation plant, representing a typical nonlinear unstable system that can be controlled by various methods. This paper shows two various approaches to the solution of the controller design based on different closed loop requirements. Starting from a known unstable linear plant model—the first method is based on the two-step procedure. In the first step, the transfer function of the controlled system is modified to get a stable non-oscillatory system. In the next step, the required first-order dynamic is defined and a model-based PI controller is proposed. The closed loop time constant of this first-order model-based approach can then be used as a tuning parameter. The second set of methods is based on a simplified ultra-local linear approximation of the plant dynamics by the double-integrator plus dead-time (DIPDT) model. Similar to the first method, one possible solution is to stabilize the system by a PD controller combined with a low-pass filter. To eliminate the offset, the stabilized system is supplemented by a simple static feedforward, or by a controller proposed by means of an internal model control (IMC). Another possible approach is to apply for the DIPDT model directly a stabilizing PID controller. The considered solutions are compared to the magnetic levitation system, controlled via the MATLAB/Simulink environment. It is shown that, all three controllers, with integral action, yield much slower dynamics than the stabilizing PD control, which gives one motivation to look for alternative ways of steady-state error compensation, guaranteeing faster setpoint step responses.

1 January 2019 in IFAC-PapersOnLine
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John RossiterJohn Rossiter
John Rossiter
KŽKatarína Žáková
Katarína Žáková
MHMikuláš Huba
Mikuláš Huba
ASA. Serbezov
A. Serbezov
Antonio VisioliAntonio Visioli
Antonio Visioli

29 June 2021 in Mathematics
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MHMikuláš Huba
Mikuláš Huba
PBPavol Bistak
Pavol Bistak
Damir VrančićDamir Vrančić
Damir Vrančić
KŽKatarína Žáková
Katarína Žáková
The article reviews the results of a number of recent papers dealing with the revision of the simplest approaches to the control of first-order time-delayed systems. The concise introductory review is extended by an analysis of two discrete-time approaches to dead-time compensation control of stable, integrating, and unstable first-order dead-time processes including simple diagnostics of the model used and focusing on the possibility of simplified but reliable plant modelling. The first approach, based on the first historically known dead-time compensator (DTC) with possible dead-beat performance, is based on the reconstruction of the actual process variables and the compensation of input disturbances by an extended state observer (ESO). Such solutions play an important role both in a disturbance observer (DOB) based control and in an active disturbance rejection control (ADRC). The second approach considered comes from the Smith predictor with two degrees of freedom, which combines feedforward control with output disturbance reconstruction and compensation by the parallel plant model. It is shown that these two approaches offer advantageous properties in the case of actuator limitations, in contrast to the commonly used PID controllers. However, when applied to integrating and unstable first-order systems, the unconstrained and possibly unobservable output disturbance signal of the second solution must be eliminated from the control loop, due to the hidden structural instability of the Smith predictor-like solutions. The modified solutions, usually referred to as filtered Smith predictor (FSP), then no longer provide a disturbance signal and thus no longer fully fit into the concept of Industry 4.0, which is focused on further optimization, predictive maintenance in dynamic systems, diagnosis, fault detection and fault identification of dynamic processes and forms the basis for the digitalization of smart production. Nevertheless, the detailed analysis of the elimination of the unstable disturbance response mode is also worth mentioning in terms of other possible solutions. The application of both approaches to the control of a thermal process shows almost equivalent quality, but with different dependencies on the tuning parameters used. It is confirmed that a more detailed identification of the controlled process and the resulting higher complexity of the control algorithms does not necessarily lead to an increase in the resulting quality of the transients, which underlines the importance of the simplified plant modelling for practice.

10 November 2011 in International Journal of Online and Biomedical Engineering (iJOE)
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MJMiroslav Jano
Miroslav Jano
KŽKatarína Žáková
Katarína Žáková
The paper deals with the web-based implementation of the control system of a thermo-optical plant. The control of the plant is based on the SciLab software which originally is not designed for web-based applications. The paper shows a possible way to circumvent this limitation. The ultimate goal is to enable remote controlled experiment using SciLab. The paper also describes possible tools for communication and control of the real plant and visualization of results.

12 February 2021 in Applied Sciences
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MHMikuláš Huba
Mikuláš Huba
Paulo Moura OliveiraPaulo Moura Oliveira
Paulo Moura Oliveira
PBPavol Bistak
Pavol Bistak
Damir VrančićDamir Vrančić
Damir Vrančić
KŽKatarína Žáková
Katarína Žáková
The paper develops and investigates a novel set of constrained-output robust controllers with selectable response smoothing degree designed for an integrator-plus-dead-time (IPDT) plant model. The input-output response of the IPDT system is internally approximated by several time-delayed, possibly higher-order plant models of increasing complexity. Since they all contain a single integrator, the presented approach can be considered as a generalization of active disturbance rejection control (ADRC). Due to the input/output model used, the controller commissioning can be based on a simplified process modeling, similar to the one proposed by Ziegler and Nichols. This allows it to be compared with several alternative controllers commonly used in practice. Its main advantage is simplicity, since it uses only two identified process parameters, even when dealing with more complex systems with distributed parameters. The proposed set of controllers with increasing complexity includes the stabilizing proportional (P), proportional-derivative (PD), or proportional-derivative-acceleration (PDA) controllers. These controllers can be complemented by extended state observers (ESO) for the reconstruction of all required state variables and non-measurable input disturbances, which also cover imperfections of a simplified plant modeling. A holistic performance evaluation on a laboratory heat transfer plant shows interesting results from the point of view of the optimal least sensitive solution with smooth input and output.