Tomas Bata University in Zlín
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Simple robust controller via evolutionary mu-synthesis using algebraic approach for oscillating plant with uncertain time delay and astatism
Get PDFApplication of Robust Control Toolbox for Time Delay Systems implemented in the Matlab system to the oscillating plant with uncertain time delay and astatism 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 for 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 proving 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.Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)]Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (LO1303, MSMT-7778/ 2014
Thiazide-associated hyponatremia: A retrospective cohort study comparing hydrochlorothiazide versus indapamide versus chlorthalidone
Get PDFHyponatremia is a crucial complication of therapy with thiazide diuretics. This study compares the epidemiological and biochemical profiles and hospital course of patients using hydrochlorothiazide (HCTZ), indapamide (INDA), and chlorthalidone (CTD) admitted with thiazide-associated hyponatremia (TAH). Data were obtained retrospectively from the hospital's digital registries. The epidemiological and biochemical parameters between the HCTZ, INDA, and CTD groups were compared. The correlation between dose and biochemical parameters in each group was performed. The thiazide groups without diuretic co-medication were compared (HCTZ vs. INDA), and the correlation between dose and biochemical parameters in each group was examined. A comparison of the HCTZ (n = 135), INDA (n = 125), and CTD (n = 27) groups identified differences in serum potassium (s-K; p = 0.03). The hyponatremia correction rate was slower in the CTD group at 96 h after admission (p < 0.001). After the exclusion of diuretic co-medication, the HCTZ group (n = 64/135) showed a higher prevalence of ARBs, s-K (both p < 0.001), and a lower median (IQR) equipotent dose (12.5 (o) mg vs. 2.5 (1.2) mg), prevalence of ACE-I (p < 0.001), and eGFR (p = 0.03), when compared to the INDA group (n = 109/125). In conclusion, except for s-K, we observed no significant difference in biochemical and epidemiological profiles between HCTZ, INDA, and CTD. After excluding the influence of other diuretics, we observed higher s-K in the HCTZ group compared to the INDA group, potentially explained by the lower equipotent dose of HCTZ. The CTD group showed a statistically significant trend of slower hyponatremia correction
Comparative analysis of polyphenolic acids from various zea mays parts in ultrasound-assisted extraction
Get PDFIn this study, we compared different parameters in the ultrasound-assisted extraction of polyphenolic acids from seven parts of Zea mays (kernels, leaves, stems, corn silks, roots, the whole plant, and the whole fermented plant) to identify its richest natural sources. Additionally, the correlation between extraction parameters and polyphenol yield was investigated. The extraction was performed using ultrasound at varying powers (480 or 240 W) and frequencies (80 or 37 kHz). Total phenolic content (TPC) was determined using the Folin–Ciocalteu assay, while radical scavenging activity (RSA) was assessed via the DPPH assay. The TPC values ranged from 0.69 ± 0.00008 mg GAE/g to 4.07 ± 0.0004 mg GAE/g in corn. RSA analysis revealed the highest scavenging activity in corn silk (80.06% ± 1.01) and the lowest in kernels (2.77% ± 0.90). High-performance liquid chromatography identified up to 22 different phenolic acids per sample, with the 5 most abundant being chlorogenic acid, protocatechuic acid ethyl ester, quercetin, sinapic acid, and trans-cinnamic acid. The study found small effects of power and frequency on the extraction efficiency. This suggests a practical advantage for industrial-scale applications, as using 240 W instead of 480 W under the same conditions can reduce energy consumption without compromising yield.Univerzita Palackého v Olomouci, UPInternal Student Grant Agency of the Palacky University in Olomouc, Czech Republic [IGA_PrF_2025_022
From Social Networks to Real Life: The Impact of Schoolboys’ Education on Respectful Behavior Towards Schoolgirls in the 4.0 era
Get PDFThis study investigated the impact of schoolboys’ education on fostering respectful behavior toward schoolgirls in the 4.0 era, characterized by pervasive digital technology and social networks. The research addressed a critical gap by focusing on boys' education as a means to promote gender respect and equality. Methodologically, the authors used a quantitative research approach, then developed an online survey using Google forms and a 5-level Likert scale to collect primary data from 260 respondents at local high schools, colleges, and Asian institutions where international students from various Asian regions study. The linear regression results revealed awareness and knowledge building play the most influential role in shaping schoolboys' education, with a strong impact score of .827. Skill development and practice also had a notable effect, scoring .69 in this digital age. Additionally, peer group norms acted as a key moderating factor (.55), enhancing the influence of awareness and knowledge building on schoolboys' education. The uniqueness of the study lay in its focus on the role of educating schoolboys to promote respect toward schoolgirls, particularly in the 4.0 era, where social media and digital technologies strongly shape perceptions and behaviors. This research specifically examined the impact of awareness-building, skill development, and the moderating role of peer group norms. Additionally, it integrated Social Learning Theory and the Theory of Planned Behavior, offering a novel framework to bridge the gap between online and real-world behaviors
Open and closed source models for LLM-generated metaheuristics solving engineering optimization problem
No full textThis paper explores the applicability of generative AI (genAI), specifically Large Language Models (LLMs), for the automatic generation and configuration of metaheuristic algorithms to address a real-world engineering problem: the optimal parameter estimation of time-delay systems in interconnected heating-cooling loops. The study introduces a pioneering workflow and iterative architecture with feedback within the emerging field of genAI-driven optimization for real optimization problems, eliminating the need for manually crafted or modified algorithms. This automated system empowers domain experts in engineering to solve complex optimization problems with minimal knowledge of optimization algorithms, lowering the barrier to entry for sophisticated algorithm use. We demonstrate how LLMs can generate effective optimizers under conditions like connstrained optimization problems where the solution lies near the boundaries of the search space. Four state-of-the-art LLMs (closed and open-sourced) have been selected for experiments. These are GPT-4o, GPT-4o mini, Claude Sonnet 3.5 and Llama 3.1. All studied LLMs generated metaheuristics that outperformed the initialization baseline optimization method (Random Search and CMA-ES). Notably, the Claude Sonnet 3.5 model generated a metaheuristic with the best mean results, almost matching the performance of the tuned state-of-the-art DISH algorithm, as an example of adaptive Differential Evolution.Fakulta aplikované informatiky, Univerzita Tomáše Bati ve Zlíně, FAI; Ministerstwo Edukacji i Nauki, MNiSW; AGH University of Krakow, (ARTIQ/0004/2021, UMO-2021/01/2/ST6/00004); Grantová Agentura České Republiky, GAČR, (GF21-45465L); Grantová Agentura České Republiky, GAČR; Univerzita Tomáše Bati ve Zlíně, UTB, (Zlin-IGA/CebiaTech/2023/004); Univerzita Tomáše Bati ve Zlíně, UTB; Narodowe Centrum Nauki, NCN, (2020/39/I/ST7/02285); Narodowe Centrum Nauki, NC
Chi-squared test particularly modified by paired test
No full textIn some cases, the statistical methods have limits, which has been brought problems with their computations. In this paper, the Chi-squared test is discussed with its limitations. The Chi-squared test is being computed by two default tables – the table of the empirical and theoretical frequencies. In case of fulfilling similarities, the zero hypothesis is failed to be rejected. In the opposite case, the zero hypothesis is rejected in favor of the alternative hypothesis. The two categorical variables are considered. The limitations based on the Chi-squared test usually have implicated the Fisher exact test, which is computationally difficult. In this paper, the situation is declared as view on the problem as the paired comparison using by the Wilcoxon or T paired test according to the normality testing
Biodegradable microplastics impact on soil: how poly-3-hydroxybutyrate alters microbial diversity and nitrogen mineralization processes
Get PDFBackground: Poly-3-hydroxybutyrate (P3HB) is a biodegradable plastic that may affect soil quality and plant growth. To explain the observed deterioration of plant growth, this study investigated the effects of P3HB microplastics on the soil microbiome and its activity related to content of nutrients and their transformation processes. A pot experiment was conducted using soil contaminated with five different doses of P3HB, both with and without maize. Soil mineral nitrogen forms, microbial properties as well as plant biomass were determined.
Results: P3HB significantly altered soil properties by stimulating microbial respiration, enhancing carbon turnover, and shifting nitrogen forms, notably reducing NO₃⁻ availability. The fungal community was more sensitive to P3HB compared to the bacterial one. Fungal genera such as Tetracladium, Exophiala, and Pseudogymnoascus were stimulated; others such as Gibberella and Gibellulopsis declined. In the bacterial community, P3HB promoted the growth of copiotrophic P3HB degraders (e.g., Actinobacteria, Alphaproteobacteria); increased the abundance of anaerobes (Clostridia); decreased nitrifying groups (Nitrososphaeria, Nitrospiria); and reduced oligotrophic taxa (Vicinamibacteria, Thermoleophilia). These changes led to altered nutrient cycling, including inhibited nitrification and reduced mineral nitrogen availability, contributing to decreased maize growth.
Conclusions: Soil contamination with ≥ 1% P3HB microplastics disrupts microbial structure and nutrient dynamics, with potential negative effects on soil fertility and plant productivity.Computational resources were provided by the e-INFRA CZ project (ID: 90254), supported by the Ministry of Education, Youth and Sports of the Czech Republic. The research was partially supported by European Union\u2019s Horizon 2020 Research and Innovation Program under Grant Agreement No. 862910 (SEALIVE), Horizon Europe project ARAGORN under grant agreement ID 101112723 and Ministry of Agriculture of the Czech Republic, institutional support MZE-RO1225. This work was also supported from OP JAC project (POCEK), number CZ.02.01.01/00/23_021/0009004.Ministry of Education, Youth and Sports of the Czech Republic [90254]; European Union [862910]; Horizon Europe project ARAGORN [101112723]; Ministry of Agriculture of the Czech Republic [MZE-RO1225]; OP JAC project (POCEK) [CZ.02.01.01/00/23_021/0009004
Fractional-order identification and analysis of elevation and azimuth dynamics in a twin rotor system
No full textAccurate modeling of complex systems is essential for the development of advanced control strategies. While traditional integer-order models have been widely applied, fractional-order modeling offers superior accuracy in capturing system dynamics. Despite its potential, research on the offline identification of fractional-order models for twin rotor systems remains limited, especially using real-time measurement data. This study addresses this gap by investigating the offline identification of fractional-order models for the elevation and azimuth angles of a twin rotor system based on real-time data. The Fractional-Order Modeling and Control (FOMCON) toolbox in MATLAB is utilized for time-domain model identification. A comparative analysis is conducted between fractional-order and integer-order models, employing MATLAB’s fminsearch function, the explicit (one-time) Least Squares Method (LSM), the Recursive Least Squares Method (RLSM), and its modified variants. Key findings demonstrate that fractional-order models yield superior performance in approximating the elevation and azimuth dynamics compared to integer-order models, achieving improved model fitness and enhanced stability. These results highlight the potential of fractional-order models to significantly improve control system design for twin rotor applications. Overall, the study contributes a robust framework for plant modeling, paving the way for more precise and adaptive control strategies in complex rotor systems.This study was supported by the Internal Grant Agency of the Tomas Bata University in Zl\u00EDn, Czech Republic, under the project number IGA/CebiaTech/024 /001
Comparison of the stiffnesses of three types of porous structures
Get PDFThe article deals with the investigation of the stiffness of selected porous structures. Three types of structures (Fisher-Koch S, Schoen IWP and Schoen F-RD) with cellular topology belonging to Triply Periodic Minimal Surfaces (TPMS) were modelled in PTC Creo software and additively manufactured by Direct Metal Laser Sintering (DMLS) technology. All samples were designed with a basic cell size of 10 x 10 x 10 mm at a specific mass of 0.5 g/cm3 to compare their properties. Based on the results, it was possible to see that the best bending stiffness was shown by the Schoen F-RD type structure.The article was prepared thanks to the support of the Ministry of Education of the Slovak Republic through the grants APVV-19-0550, APVV SK-AT-23-0008, KEGA 032TUKE-4/2022 and KEGA 042TUKE-4/2025
Graphene enhanced resonant Raman spectroscopy of gallium nitride nanocrystals
No full textThe scattering of lattice excitations (phonons) with the photoexcited charge carriers is of a major concern in optoelectronic devices. Here, the resonant Raman scattering will be utilized to study an exciton-phonon interaction in GaN nanocrystals, further enhanced by the underlying graphene. Raman spectroscopy using various excitation energies shows how the exciton-phonon interaction behaves, unveiling the scattering strength. The origin of the interaction is in the condition of resonance, which is directly observed in the temperature resolved spectra. Most importantly, the underlying graphene strongly enhances the coupling of phonons and excitons. Consequently, an enhanced resonant Raman spectrum of GaN nanocrystals possessing clearly observable phonon overtones up to the fourth order has been obtained. It has been demonstrated that the responsible effect is the electron transfer between nanocrystals and the underlying graphene. The utilization of such an increased coupling effect can be beneficial for a study of the charge carrier scattering in semiconducting nanomaterials, analysis of their crystal quality, improvement of sensor sensitivity, and in the subsequent development of new-generation optoelectronic devices.We acknowledge the support of Czech Science Foundation (Grant No. 23-07617S) and CzechNanoLab Research Infrastructure supported by MEYS CR (LM2023051). This work was also supported by the project Quantum materials for applications in sustainable technologies (QM4ST), funded as Project No. CZ.02.01.01/00/22_008/0004572 by OP JAK, call Excellent Research.Grantov Agentura Ccaron;esk Republiky10.13039/501100001824 [23-07617S]; Czech Science Foundation [LM2023051, QM4ST, CZ.02.01.01/00/22_008/0004572]; MEYS C