<p>Regional analysis is often used for flood quantile estimation in ungauged catchments. The regionalization procedure has two phases: the formation of homogeneous regions and flood quantile estimation. The presented research results consider the first phase of the regional analysis for 41 catchments in Serbia. The catchment similarity attributes are catchment area and catchment mean elevation. The number of formed regions and the number of stations within the regions are determined by maximising the mean silhouette width of the region. Regions were first obtained by cluster analysis and then adjusted to comprise catchments with a positive silhouette width. For the three formed regions, homogeneity was checked by the Gini index - GI.</p>

<p>Modern data collection, storage, and processing rely on diverse techniques to handle various types of information, ranging from structured tables to free-form text. This paper explores the captivating application of Natural Language Processing (NLP) for categorizing titles from Google Forms or any other textual data. The process of training an NLP model will be demonstrated through a specific example. Just as we learn from our past experiences, NLP models need to be fed with relevant data and labels. This ensures accurate and efficient processing even when new titles are introduced. We will conclude with a fascinating demonstration of how NLP algorithms analyze the structure and meaning of titles. By identifying keywords and understanding the context, they can automatically classify titles into relevant categories. This dramatically simplifies data organization and analysis, empowering us to extract valuable insights faster.</p>

In this paper we investigate measure-theoretic properties of the class of all weakly mixing transformations on a finite measure space which preserve measurability. The main result in this paper is the following theorem: If $\phi $ is a weakly mixing transformation on a finite measure space $( S, \mathcal A , \mu )$ with the property that $\phi (\mathcal A ) \subseteq \mathcal A ,$ then for every $A, B $ in $\mathcal A$ there is a subset $J(A,B)$ of the set of non-negative integers of density zero such that $\lim _{m \to \infty ,m \notin J(A,B)} \mu (A \cap \phi ^m(B)) = (\mu (A) / \mu (S))\lim _{n \to \infty } \mu \,(\phi^n(B)).$ Furthermore, we show that for most useful measure spaces we can strengthen the preceding statement to obtain a set of density zero that works for all pairs of measurable sets $A$ and $ B.$ As corollaries we obtain a number of inclusion theorems. The results presented here extend the well-known classical results (for invertible weakly mixing transformations), results of R. E. Rice [17] (for strongly mixing), a result of C. Sempi [19] (for weakly mixing) and previous results of the author [8, 10] (for weakly mixing and ergodicity).   2000 Mathematics Subject Classification. Primary: 28D05, 37A25; Secondary: 37A05, 47A35

Because the maternal immune system is suppressed during pregnancy, pregnant women are a risk group for COVID-19 infection. Thus, this study investigates the pregnancy outcomes of COVID-19-infected women during childbirth.Methods: A retrospective study was performed at the Department of Obstetrics and Gynecology, University Hospital Mostar, that included a total of 65 COVID-19-positive women who delivered between March 2020 and April 2022. The control group consisted of COVID-19-negative women with no detected SARS-CoV-2 infection during pregnancy or labor (n=65). The data for maternal and newborn outcomes were collected from database and medical records.Main findings: The pregnancies of COVID-19-positive women were more often completed by cesarean section (35.4%), compared to the control group (26.2%). There were no significant differences in pregnancy complications such as preterm birth, preeclampsia, gestational hypertension, preterm premature rupture of membranes, fetal growth restriction or perinatal asphyxia between the COVID-19-positive mothers and the control group. The percentage of infected newborns was 4.6% in the COVID-19-positive group.Principal conclusion: The study concludes that COVID-19-positive women experienced more adverse perinatal outcomes compared to the control group, but without statistical significance. Accordingly, the importance of perinatal surveillance of COVID-19-positive pregnancies should be emphasized. Key words: childbirth, maternal and newborn outcomes, COVID-19 infection

In this paper $\left( S(t)\right) _{t\geq 0}$ is an exponentially bounded integrated semigroup on a Banach space $X,$ with generator $A.$ We present some relations between an integrated semigroup and its generator $A,$ or its resolvent.   2000 Mathematics Subject Classification. 47D60, 47D62

In this paper we analyze the values and the properties of the function $S(n,l):=\sum_{k=0}^{n}(-1)^{k}\binom{n}{k}(n-k)^{l}\ \(n,l\in \mathbb{N\cup }\left\{ 0\right\} ),$ for $n<l.$ At first, we obtain two recurrence relations. Namely, we prove that forevery $n\in \mathbb{N\cup } \left\{ 0\right\} $ and every $l\in \mathbb{N}$ such that $l>n,$ we have\begin{equation*}S(n+1,l)=\sum_{k=1}^{l-n}\binom{l}{k}S(n,l-k),\end{equation*}and also, for every $n\in \mathbb{N\cup }\left\{ 0\right\} $and every $l\in \mathbb{N}$, we have\begin{equation*}S(n+1,l)=(n+1)S(n,l-1)+(n+1)S(n+1,l-1).\end{equation*}Further, we conclude that for every $n\geq 2$ and every $l\geq n$ the following representation formula holds\begin{multline*}S(n,l) =\sum\limits_{k_{1}=1}^{l-(n-1)}\binom{l}{k_{1}}\sum\limits_{k_{2}=1}^{l-k_{1}-(n-2)}\binom{l-k_{1}}{k_{2}}\\\cdot\sum\limits_{k_{3}=1}^{l-k_{1}-k_{2}-(n-3)}\binom{l-k_{1}-k_{2}}{k_{3}}\dots\sum\limits_{k_{n-1}=1}^{l-\sum\limits_{i=1}^{n-2}k_{i}-1}\binom{l-\sum\limits_{i=1}^{n-2}k_{i}}{k_{n-1}}.\end{multline*}We obtain an explicit formula for the calculation $S(n,l),$ especially for $ l=n+1,\dots,n+5,$ and later we give a general result.   2000 Mathematics Subject Classification. 40B05, 11Y55, 05A10

In this paper we describe five methods for the calculation of the moments\begin{equation*}\label{Momenti}\mathbb{M}_{n,m}=\int_{0}^{m}\varphi_{m}(t)t^{n}dt,n\in\mathbb{N}_{0},\end{equation*}where weight function $\varphi_{m}(\cdot)$ is the cardinal B-spline of order $m,m\in\mathbb{N}.$   2000 Mathematics Subject Classification. 65D07, 41A15

We examine the class of finite paragraded groups which we will denote by $\mathcal{P}.$ After observing that the class $\mathcal{P}$ is closed with respect to subgroups and direct products (\cite{7}), we define the notion of a pro-$\mathcal{P}$ group and consider the completion of such a group.   2000 Mathematics Subject Classification. 08A05, 16W50, 20L05, 20E18, 20-99

Single axis trackers have their application in the efficiency improvement process of photovoltaic systems. In spite of large investment costs, their application is necessary in the areas with a low amount of available solar irradiation. This is applicable only if it is required to exploit all available energy sources at any cost. With optimization and improvement of these systems it is possible to increase their efficiency, reduce energy usage for their movement and improve system reliability. Motion parameters are significant for the optimization of the system. It is necessary to set and monitor the right parameters as a prerequisite for system optimization. The process of calibration of single axis tracker prototype is shown in this paper. It is shown that proper calibration and system adjustment could improve efficiency of the system.

This paper deals with the development and testing of an intelligent vibration damping system that can real-time analyze the vibration of the system, of which it is an integral part, and acting on vibration decreasing. Damping system is based on the pendulum tuned mass damper. The system can determine combinations of changes in mechanical properties and introduce additional disturbances to achieve optimal reduction of induced vibrations. The system's performances were evaluated through experiments conducted on an experimental model. The experiment involved variations in pendulum to observe the system's response for initial perturbance. The embedded system was implemented using an Arduino controller and accompanying components such as an actuator, data acquisition device, accelerometer, and PC. The paper also discusses a proposed adaptive pendulum mass damper with real-time tuning capability for controlling structural vibrations. Combining experimental and simulation results, the paper demonstrates the effectiveness of the developed system and the adaptive pendulum mass damper in actively damping vibrations in structures.

This paper introduces a novel chaotic strategy for controlling the acceleration coefficients within the particle swarm optimization (PSO) algorithm. The PSO algorithm with chaotic exponential-based acceleration coefficients is developed to enhance the exploration of the search space and avoid premature convergence, a common issue associated with the standard PSO algorithm. The PSO algorithm with chaotic exponential-based acceleration coefficients is applied to multilevel image thresholding. The attained experimental results demonstrate that the PSO algorithm utilizing the chaotic strategy to control the cognitive and social acceleration coefficients can be successfully utilized for the selection of image thresholds across a variety of images.

We investigate the global character of the difference equation of the form $$ x_{n+1} = f(x_n, x_{n-1},\ldots, x_{n-k+1}), \quadn=0,1, \ldots $$ with several equilibrium points, where $f$ is increasing in all its variables. We show that a considerable number of well known difference equations can be embeded into this equation through the iteration process. We also show that a negative feedback condition can be used to determine a part of the basin of attraction of different equilibrium points, and that the boundaries of the basins of attractions of different locally asymptotically stable equilibrium points are in fact the global stable manifolds of neighboring saddle or non-hyperbolic equilibrium points.   2000 Mathematics Subject Classification. 39A10, 39A11

We consider the following system of rational difference equations in the plane: $$\left\{\begin{aligned}%{rcl}x_{n+1} &= \frac{\alpha_1}{A_1+B_1 x_n+ C_1y_n} \\[0.2cm]y_{n+1} &= \frac{\alpha_2}{A_2+B_2 x_n+ C_2y_n}\end{aligned}\right. \, , \quad n=0,1,2,\ldots $$ where the parameters $\alpha_1, \alpha_2, A_1, A_2, B_1, B_2, C_1, C_2$ are positive numbers and initial conditions $x_0$ and $y_0$ are nonnegative numbers. We prove that the unique positive equilibrium of this system is globally asymptotically stable. Also, we determine the rate of convergence of a solution that converges to the equilibrium $E=(\bar{x},\bar{y})$ of this systems.   2000 Mathematics Subject Classification. 39A10, 39A11, 39A20

We investigate the period-two trichotomies of solutions of the equation $$x_{n+1} = f(x_{n}, x_{n-1},x_{n-2}), \quad n=0, 1, \ldots $$ where the function $f$ satisfies certain monotonicity conditions. We give fairly general conditions for period-two trichotomies to occur and illustrate the results with numerous examples.   1991 Mathematics Subject Classification. 39A10, 39A11