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In this research paper, a comprehensive analysis of particulate matter (PM10) and nitrogen dioxide (NO2) pollution concentrations in six different Lithuanian regions is presented. The analysis employs data smoothing, principal component analysis (PCA), exploratory data analysis, hypothesis testing, and time series analysis to provide a thorough examination. Functional data analysis approaches were used to find the origins and effects of these air pollutants by revealing their data patterns. The functional data analysis techniques demonstrate their effectiveness in revealing deep links within large datasets, assisting in the control of air quality problems. This research provides valuable insights into air quality challenges in Lithuanian regions. The study, aimed at comparing air quality across different regions, indicates that there are no significant differences in PM10 and NO2 between the two groups. Notably, reliable forecasts for 2023 data are attainable for PM10 in regions such as Vilnius Old Town, Vilnius Lazdynai, Šiauliai, and Klaipėda. For NO2, successful forecasting can be applied to Vilnius Old Town, Vilnius Lazdynai, and Šiauliai.

In this paper we consider a modification of the attack on the classic RSA cryptosystem aimed at factoring the public modulus n, which is a product of three primes. To improve the performance of the modified attack we introduce additional parameters. We present the theoretical upper bound on the search range parameter and define a shifting parameter based on the empirical results. Since these changes make our attack probabilistic, we investigate the dependence of the success on the values of the newly defined parameters.

Usually, proofs of mathematical statements involve both algebraic rearrangements and logical reasoning. But there are mathematical statements whose truth is obvious at first glance when there is a diagram illustrating that proof. Although the proofs based on the drawing are not necessarily full and complete, but the drawing helps to notice facts that are then easily supported by algebra and logic. The paper presents proofs of mathematical propositions where, upon careful study of the drawing, the main idea of the proof can be seen from the drawing, and the proof itself becomes beautiful and clear.

In this paper the error estimation for n-th order Filon quadrature formula is discussed.

BDI logic is widely used to describe agent based systems, since it can express a lot of different real world domains with three main operators: belief, desire and intention. There are lots of works where BDI logic is used as descriptive language, but authors do not talk about implementation issues [5,2,4,8,1]. There is even known general agent implementation scheme, which do not describe howto use formal logic for such scheme implementation [12]. The main aim of this paper is to show the bridge, which connects formal and practical parts of logic. We describe how sequent calculus can be used for implementing some parts of general scheme. In this paper, we show how flexible constraints can be implemented. Sequent calculus usage is illustrated with simple examples.

A hyperbolic system of first order partial differential equations with small parameter and periodical initial conditions is obtained. The uniformly valid in a long time interval asymptotical solution can be constructed using the averaging along characteristics of the system. The asymptotical estimation of the approximation is made in the paper. Some aspects of practical realization of the method are discussed in the work too.

In this paper we present estimated generalized least squares (EGLS) estimator for the coefficient vector β in the linear regression model y = βX + ε, where disturbance term can be heteroskedastic. For the heteroskedasticity of the changed segment type, using Monte-Carlo method, we investigate empirical properties of the proposed and ordinary least squares (OLS) estimators. The results show that the empirical covariance of the EGLS estimators is smaller than that of OLS estimators.

In this paper the local limit theorem for density of k-th maxima of independent identically distributed random variables is proved.

Large-scale aggregation and its inverse, disaggregation, problems are important in many fields of studies like macroeconomics, astronomy, hydrology and sociology. It was shown in Granger (1980) that a certain aggregation of random coefficient AR(1) models can lead to long memory output. Dacunha-Castelle and Oppenheim (2001) explored the topic further, answering when and if a predefined long memory process could be obtained as the result of aggregation of a specific class of individual processes. In this paper, the disaggregation scheme of Leipus et al. (2006) is briefly discussed. Then disaggregation into AR(1) is analyzed further, resulting in a theorem that helps, under corresponding assumptions, to construct a mixture density for a given aggregated by AR(1) scheme process. Finally the theorem is illustrated by FARUMA mixture densityÆs example.

The Baltic States equity market is a challenge for investors and financial analysts. Unfortunately strong assivity is observed in ``young'' markets, therefore any (Gaussian, α-stable etc) distribution fitting tests (Anderson–Darling, Kolmogorov–Smirnov, etc.) are poorly applicable. Improvement based on mixed distributions is proposed and its adequacy in the Baltic States market is tested. In this paper we use Koutrouvelis goodness-of-fit test and modified χ2 test.

The paper is devoted to multivariate statistical analysis of academic performance data. The phenomina of general grade inflation and the effect of the first passing of an egzam on grades of the egzam are investigated by making use of general linear (mixed) model and logistic regresion.

The paper describes shortly the main principles of representative examples development, provides the essence of the methodology to develop representative examples and an example of its application. The main contribution of the paper is the methodology to develop representative examples that could be used to evaluate the sufficiency of specification language for specification of software system requirements.

In this paper enrolment and study problems in the faculty of Mathematics and informatics of Vilnius Pedagogical university are discussed.

The analysis of heuristic algorithm for solving two dimensional cutting stock problem is presented in this paper.

The analysis of machine scheduling problem and possible algorithms for solving it are presented in this paper.

The subject of this work is the analysis of hazard distribution in the network systems. In the age when transport flows in the railway and road systems, information flows in the internet channels, etc. intensify, hazard distribution in the network systems becomes a more relevant and important issue. In the paper various theoretical hazard type distributions in the network systems are analysed. Mathematical model of hazard distribution and accumulation in the nodes of the network was created.

In this paper DNA sequents are modelled as discrete-state Markov chains. Statistical data is presented in contingency tables form. The generalized logit model is used to test the first-order Markov property for all coding and non-coding subsequences of DNA.

Poisson approximation for the sum of independent random variables is investigates in this paper.

This paper considered deterministic and stochastic delayed linear growth laws for the modeling of the process of growth. For the estimation of parameters the L1 distance procedure was proposed. As an illustrative experience was used a real data set from repeated measurements on permanent sample plots of pine stands in Lithuania.

In this paper the discrete logarithm problem in matrix in finite fields is formulated, possible ways of solution are given.

One of the ways to improve the accuracy of probability density estimation is multi-mode density treating as the mixture of single-mode one. In this paper we offer to use data clustering in the first place and to estimate density in every cluster separately. To objectively compare the performance, Monte Carlo approximation is used. While using various methods to evaluate the accuracy of probability density estimations we tried to use clustered and not clustered data. In this paper we also tried to reveal the usefulness of using clustering for data generated by single-mode and multi-mode distributions.

The reflective study models are quite frequent and well analyzed in the scientific literature. Still their realization premises being different in many countries keep forming a scientific issue which needs a special attention, especially in learning mathematics. In this context there arises a problem question: what are the realization limitations of the traditional and reflective mathematics learning models? The research paper consists of two parts. The first part clears a problems of the realization a traditional study model. The second part clears out the possible realization limitations of the above mentioned model in Lithuanian context.

This paper deals with an analysis of the electrochemical biosensors and their response to multi-component mixtures. The main task is to build a mathematical model for estimation the concentration of each mixture component from the biosensor response data. Two different types of biosensors: amperometric and potenciometric are analysed. Due to high dimensionality of biosensor output data the principal component analysis is applied. Additional multivariate analysis of variance is used to analyze the response sensitivity of each biosensor type. Finally a concentration estimation model based on ensemble of neural networks is presented.

Multiple criteria decision-making methods enable to choose the optimal decision, if his criterions is contradictorys. In herein paper is describe MAUT – multiattribute utility theory. This method is reasoned in theory. MAUT up for indeterminations situations, but can to use for determinations situations. In this method multiple criteria problem solvable with the help of unitary utility functions.

The analysis of ACO algorithm for transmitters locating problem is presented in this paper.

In this paper we present separate cases of Sturm–Liouville problem with nonlocal two-point boundary condition. The existence of positive eigenvalues and eigenfunctions is analysed. Obtained results we compare with results that are described in paper [1] and denote that in some cases they don’t coincide.

The paper reviews the visualisation problems of genetic sequences and of their analysis results as well as other related problems. A possible formulation of the problem based on similarity, complexity measure (distance) between DNA sequences is proposed. It is solved by making use of multidimensional scaling (MDS) of principal component analysis (PCA) methods.

The positioning problem considered in this paper is an attempt to find system’s of a few points position using accelerations. Today’s industry provides with various types of accelerometers suitable for acceleration measure. That data may be used to trace object movement. Final results showed that such movement trace is possible and may be applicable. The results also showed origins for errors which according to the results, are quite high globally. The final conclusion follows: the model created must be analized further in a deeper level, and error origins must be eliminated or at least minimized by either chosing different solving or modeling methods, either by revising used ones.

The present paper deals with efficiency improvement of backward proof-search of sequents of propositional linear temporal logic, using a loop-type sequent calculus. The improvement is achieved by syntactic transformation of sequents into equivalent to them simpler ones. It is proved that some formulas can be removed from sequents with no impact on their derivability.

In Plato’s later ethics, the key challenge to one’s personal progress is unorderly thoughts and motions of soul. This disorder should be corrected by recognising and repeating the orderly thoughts and motions of cosmic gods. This paper examines the theoretical assumptions of Plato’s later ethics. A closer analysis of the Timaeus reveals a peculiar conception of mathematics, according to which numbers and their relations not only reveal facts about the reality, but also express values and ideals. By learning mathematics human beings come to know the everyday ethical life of cosmic gods and become like them.

In this paper authors research the problem of traceability of assumptions in logical derivation. The essence of this task is to trace which assumptions from the available knowledge base of assumptions are necessary to derive a certain conclusion. The paper presents a new derivation procedure for propositional logic, which ensures traceability feature. For the derivable conclusion formula derivation procedure also returns the smallest set of assumptions those are enough to get derivation of the conclusion formula. Verification of the procedure were performed using authors implementation.

In this paper the multidimensional scaling, the principal coordinate and principal component methods for the Lithuanian population structure have investigated, taken that the proximity measures are Euclid, Gower, Bray-Curtis, Kulczynski, Jaccard and Morisita. The genome-wide single nucleotide polymorphism genetic data analyzed. A comparative analysis of proximity measures performed. The results of visualization are also presented.

In this paper, spatial data specified by auto-beta models is analysed by considering a supervised classification problem of classifying feature observation into one of two populations. Two classification rules based on conditional Bayes discriminant function (BDF) and linear discriminant function (LDF) are proposed. These classification rules are critically compared by the values of the actual error rates through the simulation study.

The article presents several observations about the examination papers of the state-level Maturity Examinations in Mathematics in the years 2014–2021 in Lithuania. Some inaccuracies were observed in the appendix of the paper titled ``Mathematical formulas'', in the wordings of the problems. Also the issue of proof problems in the examination is discussed. The purpose of these observations is to draw attention to areas for improvement in the examination system. The article presents the subjective opinion of the authors.

Floyd's triangle is often presented to computer science students as an exercise or example to illustrate the concepts of text formatting and loop constructs. The paper proposes to look at an object from a different angle and to examine limit theorems for the numbers of generalized Floyd's triangles. Tasks of this type can be used as exercises in study programs of mathematics and informatics (couses of probability theory and combinatorics). It would help to master the appropriate proof techniques and mathematical apparatus. The article proposes a series of possible problems and their proof schemes.

In this paper, relations between discrete Sturm--Liouville problem with nonlocal integral boundary condition characteristics (poles, critical points, spectrum curves) and graphs characteristics (vertices, edges and faces) were found. The previous article was devoted to the Sturm--Liouville problem in the case two-points nonlocal boundary conditions.

In recent years, a lot of research has focused on understanding the behavior of when synchronous and asynchronous phases occur, that is, the existence of chimera states in various networks. Chimera states have wide-range applications in many disciplines including biology, chemistry, physics, or engineering. The object of research in this paper is a coupled map lattice of matrices when each node is described by an iterative map of matrices of order two. A regular topology network of iterative maps of matrices was formed by replacing the scalar iterative map with the iterative map of matrices in each node. The coupled map of matrices is special in a way where we can observe the effect of divergence. This effect can be observed when the matrix of initial conditions is a nilpotent matrix. Also, the evolution of the derived network is investigated. It is found that the network of the supplementary variable $\mu$ can evolve into three different modes: the quiet state, the state of divergence, and the formation of divergence chimeras. The space of parameters of node coupling including coupling strength $\varepsilon$ and coupling range $r$ is also analyzed in this study. Image entropy is applied in order to identify chimera state parameter zones.

This paper presents an investigation of modeling and solving of differential equations in the study of mechanical systems with holonomic constraints. The 2D and 3D mathematical models of constrained motion are made. The structure of the models consists of nonlinear first or second order differential equations. Cases of free movement and movement with resistance are investigated. Solutions of the Cauchy problem of obtained differential equations were obtained by Runge–Kutta method.

This paper examines the Lithuanian consumer price inflation from 1996 January till 2006 December using a modern non-stationary time series and econometric theory. The multiple regressionmodels are proposed for inflation modeling. The stationarity of Lithuanian inflation and the main explored exogenous variables are analyzed using the augmented Dickey–Fuller test. All indicators are integrated of order one. Vector error correction (VECM) model of Lithuanian inflation processes is investigated and proposed for inflation modeling.

In this paper,we study a transformationof pure hybrid logic formulae,which do not have binding operator, into an equivalent normal form, which does not have any satisfiability operators in the scope of another satisfiability operator.

In the paper the global optimization problem of truss systems is studied. The genetic algorithms are employed for the optimization. As the objective function the structure mass is treated; the constraints include equilibrium, local stability and other requirements. All the truss system characteristics needed for genetic algorithm are obtained via finite element solution. Topology optimization of truss system is performed using original modified genetic algorithm, while the shape optimization – using ordinary genetic algorithm. Numerical solutions are presented. The obtained solutions are compared with global extremes obtained using full search algorithm. All the numerical examples are solved using original software.

The technology for automatization of lecturer’sworkplace is presented in the paper, enhancing and simplifying the preparation of assignments for practical works and their inspection. The main focus of paper is placed on the inspection of students’works. The informational system created and exploited at the department of EngineeringMechanics, Vilnius Gediminas TechnicalUniversity, is described. Similar principles may be employed also for analogical systems of generating of assigments for practical works as well as inspection of them for other subjects (mathematics, informatics, etc).

In this paper extreme learning machine and support vector regression are used for biosensors response to mixtures of compounds classification. The results are compared with the results obtained using artificial neural networks and others.

In this paper we investigate a simple AR(1) model by testing a presence of changed segment in a data. We suggest test statistics based on a behavior of partial sums of residuals.

The analysis of cutting stock problem and heuristic and metaheuristic algorithms for solving it are presented in this paper.

Programming Style is an important part of program quality and it should be taken into account while assessing programs designedby competitors in informatics. In InternationalOlympiad in Informatics grading is automated and based on testing results only, while programming style is not taken into account. However there exists practice in universities in programming courses where programming style of submitted programs is evaluated automatically. The paper reviews existing experience and discusses possibilities for automated grading of programming style in informatics olympiads.

The paper analyses graph oriented ontology transformation into conceptual data model. A number of methodswere proposed to develop conceptual datamodels, but only fewdealswith knowledge reuse. In this paperwe present an approach for knowledge represented by ontology automatic transformation into conceptual data model. The graph transformation language is presented and adapted for formal transformation of ontology into conceptualmodel. Details and examples of proposed ontology transformation into conceptual data model are presented.

Paper deals with statistical classification of spatial data as a part of widely applicable statistical approach to pattern recognition. Error rates in supervised classification of Gaussian random field observation into one of two populations specified by different constant means and common stationary geometric anisotropic covariance are considered. Formula for the exact Bayesian error rate is derived. The influence of the ratio of anisotropy to the error rates is evaluated numerically for the case of complete parametric certainty.

In this paper the problem of classification of an observation into one of two Gaussian populations with different means and common variance is considered in the case when equicorrelated training sample is given. Unknown means and common variance are estimated from training sample and these estimators are pluged in the Bayes discriminant function. The maximum likelihood estimators are used. The approximation of the expected error rate associated with Bayes plug-in discriminant function is derived. Numerical analysis of the accuracy of that approximation for various values of correlation is presented.