Technical University of Košice

Dynamic systems of an arbitrary real order (fractional-order systems) are considered. The concept of a fractional-order PI/sup /spl lambda//D/sup /spl mu//-controller, involving fractional-order integrator and fractional-order differentiator, is proposed. The Laplace transform formula for a new function of the Mittag-Leffler-type made it possible to obtain explicit analytical expressions for the unit-step and unit-impulse response of a linear fractional-order system with fractional-order controller for both open- and closed-loops. An example demonstrating the use of the obtained formulas and the advantages of the proposed PI/sup /spl lambda//D/sup /spl mu//-controllers is given.

Many real dynamic systems are better characterized using a non-integer order dynamic model based on fractional calculus or, differentiation or integration of non-integer order. Traditional calculus is based on integer order differentiation and integration. The concept of fractional calculus has tremendous potential to change the way we see, model, and control the nature around us. Denying fractional derivatives is like saying that zero, fractional, or irrational numbers do not exist. In this paper, we offer a tutorial on fractional calculus in controls. Basic definitions of fractional calculus, fractional order dynamic systems and controls are presented first. Then, fractional order PID controllers are introduced which may make fractional order controllers ubiquitous in industry. Additionally, several typical known fractional order controllers are introduced and commented. Numerical methods for simulating fractional order systems are given in detail so that a beginner can get started quickly. Discretization techniques for fractional order operators are introduced in some details too. Both digital and analog realization methods of fractional order operators are introduced. Finally, remarks on future research efforts in fractional order control are given.

A solution to the more than 300-years old problem of geometric and physical interpretation of fractional integration and differentiation (i.e., integration and differentiation of an arbitrary real order) is suggested for the Riemann-Liouville fractional integration and differentiation, the Caputo fractional differentiation, the Riesz potential, and the Feller potential. It is also generalized for giving a new geometric and physical interpretation of more general convolution integrals of the Volterra type. Besides this, a new physical interpretation is suggested for the Stieltjes integral.

This paper describes the methodology and application of the very popular nonparametric test which is a rank based test named as Kruskal-Wallis. This test is useful as a general nonparametric test for comparing more than two independent samples. It can be used to test whether such samples come from the same distribution. This test is powerful alternative to the one-way analysis of variance. Nonparametric ANOVA has no assumption of normality of random error but the independence of random error is required. If the Kruskal-Wallis statistic is significant, the nonparametric multiple comparison tests are useful methods for further analysis. The statistical analysis of the application data in this paper was performed with software MATLAB.

This article reviews the using of the original Modal Assurance Criterion (MAC). The Modal Assurance Criterion is a statistical indicator that is most sensitive to large differences and relatively insensitive to small differences in the mode shapes. This yields a good statistic indicator and a degree of consistency between mode shapes. The MAC considers only modal shapes which mean that a separate frequency comparison must be used in conjunction with the MAC values to determine the correlated mode pairs. The MAC is often to used to pair modes shapes derived from analytical models with those obtained experimentally. It is easy to apply and does not require an estimate of the system matrices. It is bounded between 0 and 1, with 1 indicating fully consistent mode shapes. It can only indicate consistency and does not indicate validity or orthogonality. A value near 0 indicates that the modes are not consistent.

This paper is concentrated on the polynomial regression model, which is useful when there is reason to believe that relationship between two variables is curvilinear. The polynomial regression model has been applied using the characterisation of the relationship between strains and drilling depth. Parameters of the model were estimated using a least square method. After fitting, the model was evaluated using some of the common indicators used to evaluate accuracy of regression model. The data were analyzed using computer program MATLAB that performs these calculations.

Nowadays, the material recycling is a growing trend in development of building materials and therefore using of secondary raw materials for production new building materials is in accordance with sustainable development in civil engineering. Therefore, it is increasingly becoming crucial to accelerate the transition from application of non-renewable sources of raw materials to renewable raw materials. One fast renewable resource is natural plant fibers. The use of the cellulosic fibers as environmentally friendly material in building products contributes to the environmental protection and saves non-renewable resources of raw materials. Wood fibers and recycled cellulose fibers of waste paper appear as suited reinforcing elements for cement-based materials. In this paper, there is used application of Fourier transform infrared spectroscopy (FTIR) on cellulose fibers coming from different sources. FTIR spectra of cellulose fiber samples are investigated and compared with reference sample of cellulose.

Abstract At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark–gluon plasma (QGP) 1 . Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed 2,3,4,5,6 . Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions 7 , is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton–proton (pp) collisions 8,9 , but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton–proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The measurements are in remarkable agreement with the p–Pb collision results 10,11 , indicating that the phenomenon is related to the final system created in the collision. In high-multiplicity events strangeness production reaches values similar to those observed in Pb–Pb collisions, where a QGP is formed.

OBJECTIVE: To compare the safety and efficacy of parenteral methotrexate (MTX) at an intermediate dosage (15 mg/m(2)/week) versus a higher dosage (30 mg/m(2)/week) in patients with polyarticular-course juvenile idiopathic arthritis (JIA) who failed to improve while receiving standard dosages of MTX (8-12.5 mg/m(2)/week). METHODS: In the screening phase, 595 patients who were newly started on a standard dose of MTX were followed up for 6 months. Subsequently, the nonresponders, defined according to the American College of Rheumatology (ACR) pediatric 30% improvement criteria (pediatric 30), were randomized to receive an intermediate dose or higher dose of parenteral MTX for an additional 6 months. Improvement in the screening and randomization phase was defined by the ACR pediatric 30 response, as well as by the 50% and 70% response levels (ACR pediatric 50 and ACR pediatric 70, respectively). RESULTS: In the screening phase, after receiving standard doses of MTX, 430 patients (72%) improved according to the ACR pediatric 30, while 360 (61%) met the ACR pediatric 50 and 225 (38%) met the ACR pediatric 70; among these patients, 69 (12%) also met the definition of complete disease control. Of the 133 nonresponders, 80 were randomized to receive an intermediate dose or higher dose of MTX. In the randomization phase, the ACR pediatric 30 response rate was 25 of 40 children (62.5%) in the intermediate-dose group versus 23 of 40 children (57.5%) in the higher-dose group. An ACR pediatric 50 response rate was attained by 23 patients (57.5%) receiving an intermediate dose versus 22 (55%) in the higher-dose group. An ACR pediatric 70 response rate was seen in 18 children (45%) receiving an intermediate dose versus 19 (47.5%) receiving a higher dose. Five children (12.5%) in the intermediate-dose group versus 4 (10%) receiving the higher dose of MTX also met the definition of complete disease control. None of the intergroup differences in response rate were significant. There were no significant differences in the frequency of adverse events or laboratory abnormalities between the 2 randomized groups. CONCLUSION: This study shows that the plateau of efficacy of MTX in JIA is reached with parenteral administration of 15 mg/m(2)/week and that a further increase in dosage is not associated with any additional therapeutic benefit. MTX should be administered for up to 9-12 months to appreciate its full therapeutic effect.

OBJECTIVE: Juvenile localized scleroderma is usually considered a disease that is confined to the skin and subcutaneous tissue. We studied the prevalence and clinical features of extracutaneous manifestations in a large cohort of children with juvenile localized scleroderma. METHODS: Data from a multinational study on juvenile scleroderma was used for this in-depth study. Clinical features of patients with extracutaneous manifestations were compared with those of patients who had exclusively skin involvement. RESULTS: Seven hundred fifty patients entered the study. One hundred sixty-eight patients (22.4%) presented with a total of 193 extracutaneous manifestations, as follows: articular (47.2%), neurologic (17.1%), vascular (9.3%), ocular (8.3%), gastrointestinal (6.2%), respiratory (2.6%), cardiac (1%), and renal (1%). Other autoimmune conditions were present in 7.3% of patients. Neurologic involvement consisted of epilepsy, central nervous system vasculitis, peripheral neuropathy, vascular malformations, headache, and neuroimaging abnormalities. Ocular manifestations were episcleritis, uveitis, xerophthalmia, glaucoma, and papilledema. In more than one-fourth of these children, articular, neurologic, and ocular involvements were unrelated to the site of skin lesions. Raynaud's phenomenon was reported in 16 patients. Respiratory involvement consisted essentially of restrictive lung disease. Gastrointestinal involvement was reported in 12 patients and consisted exclusively of gastroesophageal reflux. Thirty patients (4%) had multiple extracutaneous features, but systemic sclerosis (SSc) developed in only 1 patient. In patients with extracutaneous involvement, the prevalence of antinuclear antibodies and rheumatoid factor was significantly higher than that among patients with only skin involvement. However, Scl-70 and anticentromere, markers of SSc, were not significantly increased. CONCLUSION: Extracutaneous manifestations of juvenile localized scleroderma developed in almost one-fourth of the children in this study. These extracutaneous manifestations often were unrelated to the site of the skin lesions and sometimes were associated with multiple organ involvement. The risk of developing SSc was very low. This subgroup of patients with juvenile localized scleroderma should be evaluated extensively, treated more aggressively, and monitored carefully.

Abstract In recent years, magnetism has gained an enormous amount of interest among researchers for actuating different sizes and types of bio/soft robots, which can be via an electromagnetic‐coil system, or a system of moving permanent magnets. Different actuation strategies are used in robots with magnetic actuation having a number of advantages in possible realization of microscale robots such as bioinspired microrobots, tetherless microrobots, cellular microrobots, or even normal size soft robots such as electromagnetic soft robots and medical robots. This review provides a summary of recent research in magnetically actuated bio/soft robots, discussing fabrication processes and actuation methods together with relevant applications in biomedical area and discusses future prospects of this way of actuation for possible improvements in performance of different types of bio/soft robots.

Current research examines the impact of academic and familial stress on students' depression levels and the subsequent impact on their academic performance based on Lazarus' cognitive appraisal theory of stress. The non-probability convenience sampling technique has been used to collect data from undergraduate and postgraduate students using a modified questionnaire with a five-point Likert scale. This study used the SEM method to examine the link between stress, depression, and academic performance. It was confirmed that academic and family stress leads to depression among students, negatively affecting their academic performance and learning outcomes. This research provides valuable information to parents, educators, and other stakeholders concerned about their childrens' education and performance.

The activation function plays an important role in the training and the performance of an Artificial Neural Network. They provide the necessary non-linear properties to any Artificial Neural Network. In this work, we provide a review of the most common and recent activation functions used in the hidden layer of an artificial Neural Network.

Abstract A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate‐resilient energy systems and infrastructures brings with it a long‐term direction, so as a result the long‐term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind “Corrosion Challenges Towards a Sustainable Society” presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics.

The pseudorapidity density of charged particles, $d{N}_{\mathrm{ch}}/d\ensuremath{\eta}$, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of $\sqrt{{s}_{NN}}=5.02\text{ }\text{ }\mathrm{TeV}$. For the 5% most central collisions, we measure a value of $1943\ifmmode\pm\else\textpm\fi{}54$. The rise in $d{N}_{\mathrm{ch}}/d\ensuremath{\eta}$ as a function of $\sqrt{{s}_{NN}}$ is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of $d{N}_{\mathrm{ch}}/d\ensuremath{\eta}$ as a function of the average number of participant nucleons, $⟨{N}_{\text{part}}⟩$, calculated in a Glauber model, is compared with the previous measurement at $\sqrt{{s}_{NN}}=2.76\text{ }\text{ }\mathrm{TeV}$. A constant factor of about 1.2 describes the increase in $d{N}_{\mathrm{ch}}/d\ensuremath{\eta}$ from $\sqrt{{s}_{NN}}=2.76$ to 5.02 TeV for all centrality classes, within the measured range of 0%--80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.

The effect of chemical treatment of hemp hurds slices in three solutions (EDTA (Ethylenediaminetetraacetic acid), NaOH and Ca(OH)₂) on the properties of natural material was discussed in this paper. Changes in the morphology, chemical composition and structure as well as thermal stability of hemp hurds before and after their modification were investigated by using FTIR (Fourier transform infrared spectroscopy), XRD (X-ray powder diffraction analysis) and TG (thermogravimetry)/DSC (differential scanning calorimetry). Size exclusion chromatography (SEC) measurements were used for determination of degree of cellulose polymerization of hemp hurd samples. Chemical modification is related to the partial removal of non-cellulosic components of lignin, hemicellulose and pectin as well as waxes from the surface of hemp hurd slices. Another effect of the chemical treatment applied is connected with increasing the crystallinity index of cellulose determined by FTIR and XRD methods. Decrease in degree of cellulose polymerization and polydispersity index in chemically modified hemp hurds compared to the original sample was observed. Increase in thermal stability of treated hemp hurd was found. The most significant changes were observed in alkaline treated hemp hurds by NaOH.

Customer satisfaction (CS) has become an important issue for commercial and public service organisations. Companies win or lose based on what percentage of their customers they can keep. Success is largely about retention of customers, which again depends on CS level. It would be a great help to be able to comprehensively measure the quality of product and service, by relating the measures of quality to real customer behaviour. Some companies get feedback about CS through the percentage of complaints, some through non‐systematic surveys, again some do not measure CS at all, because “the system would not add anything useful and is very time‐consuming”. Give three managers in the same company the same objective: to improve CS, however it may be measured, and they will come up with three distinctly different and incompatible plans. CS requires a number of ingredients, all of which need to be considered. Aims to develop and simplify measurement systems by using a general formula that makes quantitative measurement of CS possible. Considers four important aspects that have a negative or positive influence on profitability related to CS.

The ALICE Collaboration reports unique data on particle production in Pb-Pb and inelastic $p$-$p$ collisions at the LHC at 5.02 TeV. The measurements range from very peripheral to the most central collisions, and cover particles with transverse momenta from hundreds of MeV/$c$ to 20 GeV/$c$. The precision and breadth of the data provide tight constraints on our understanding of particle production mechanisms in these collisions.

This paper presents the results of modelling the heat transfer process in heterogeneous media with the assumption that part of the heat flux is dispersed in the air around the beam. The heat transfer process in a solid material (beam) can be described by an integer order partial differential equation. However, in heterogeneous media, it can be described by a sub- or hyperdiffusion equation which results in a fractional order partial differential equation. Taking into consideration that part of the heat flux is dispersed into the neighbouring environment we additionally modify the main relation between heat flux and the temperature, and we obtain in this case the heat transfer equation in a new form. This leads to the transfer function that describes the dependency between the heat flux at the beginning of the beam and the temperature at a given distance. This article also presents the experimental results of modelling real plant in the frequency domain based on the obtained transfer function.

Albertsson, Kim; Altoe, Piero; Anderson, Dustin; Andrews, Michael; Araque Espinosa, Juan Pedro; Aurisano, Adam; Basara, Laurent; Bevan, Adrian; Bhimji, Wahid; Bonacorsi, Daniele; Calafiura, Paolo; Campanelli, Mario; Capps, Louis; Carminati, Federico; Carrazza, Stefano; Childers, Taylor; Coniavitis, Elias; Cranmer, Kyle; David, Claire; Davis, Douglas; Duarte, Javier; Erdmann, Martin; Eschle, Jonas; Farbin, Amir; Feickert, Matthew; Castro, Nuno Filipe; Fitzpatrick, Conor; Floris, Michele; Forti, Alessandra; Garra-Tico, Jordi; Gemmler, Jochen; Girone, Maria; Glaysher, Paul; Gleyzer, Sergei; Gligorov, Vladimir; Golling, Tobias; Graw, Jonas; Gray, Lindsey; Greenwood, Dick; Hacker, Thomas; Harvey, John; Hegner, Benedikt; Heinrich, Lukas; Hooberman, Ben; Junggeburth, Johannes; Kagan, Michael; Kane, Meghan; Kanishchev, Konstantin; Karpiński, Przemysław; Kassabov, Zahari; Kaul, Gaurav; Kcira, Dorian; Keck, Thomas; Klimentov, Alexei; Kowalkowski, Jim; Kreczko, Luke; Kurepin, Alexander; Kutschke, Rob; Kuznetsov, Valentin; Köhler, Nicolas; Lakomov, Igor; Lannon, Kevin; Lassnig, Mario; Limosani, Antonio; Louppe, Gilles; Mangu, Aashrita; Mato, Pere; Meinhard, Helge; Menasce, Dario; Moneta, Lorenzo; Moortgat, Seth; Narain, Meenakshi; Neubauer, Mark; Newman, Harvey; Pabst, Hans; Paganini, Michela; Paulini, Manfred; Perdue, Gabriel; Perez, Uzziel; Picazio, Attilio; Pivarski, Jim; Prosper, Harrison; Psihas, Fernanda; Radovic, Alexander; Reece, Ryan; Rinkevicius, Aurelius; Rodrigues, Eduardo; Rorie, Jamal; Rousseau, David; Sauers, Aaron; Schramm, Steven; Schwartzman, Ariel; Severini, Horst; Seyfert, Paul; Siroky, Filip; Skazytkin, Konstantin; Sokoloff, Mike; Stewart, Graeme; Stienen, Bob; Stockdale, Ian; Strong, Giles; Thais, Savannah; Tomko, Karen; Upfal, Eli; Usai, Emanuele; Ustyuzhanin, Andrey; Vala, Martin; Vallecorsa, Sofia; Vasel, Justin; Verzetti, Mauro; Vilasis-Cardona, Xavier; Vlimant, Jean-Roch; Vukotic, Ilija; Wang, Sean-Jiun; Watts, Gordon; Williams, Michael; Wu, Wenjing; Wunsch, Stefan; Zapata, Omar