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The PCA-seq method applied to analyze of the dynamics of COVID-19 epidemic indicators. Journal of Physics: Conference Series, 1715(1), [012025]. https://doi.org/10.1088/1742-6596/1715/1/012025
Journal of Physics: Conference Series. 2021. No. 1715 .
Efimov V. M., Polunin D. A., Kovaleva V. Y., Efimov K.
In time series analysis using the SSA method, a univariate series is converted into the multivariate one by shifts. The resulting trajectory matrix is subjected to principal component analysis (PCA). However, the principal components can also be computed using the PCA-Seq method if segments of the original series are selected as objects. The matrix of Euclidean distances between the objects can be obtained using any method, which offers additional opportunities for time series analysis compared to the conventional SSA. In this study, the PCA-Seq method was used to analyze the dynamics of COVID-19 epidemic indicators.
Gusev I., Maksaev A., Promyslov V., Journal of Mathematical Sciences 2025 Vol. 299 No. 6
The regular graph of the space of n × m matrices over a field F is defined as the undirected graph whose vertices are matrices of rank min(n, m), and distinct matrices A and B are connected by an edge if and only if rk(A + B) < min(n, m). In this paper, for |F| ...
Added: May 25, 2026
Tyukin I., Tyukina T., van Helden D. P. et al., Information Sciences 2024 Vol. 678 Article 120856
AI errors pose a significant challenge, hindering real-world applications. This work introduces a novel approach to cope with AI errors using weakly supervised error correctors that guarantee a specific level of error reduction. Our correctors have low computational cost and can be used to decide whether to abstain from making an unsafe classification. We provide ...
Added: May 23, 2026
Zaikin A., Sviridov I., Sosedka A. et al., Technologies 2026 Vol. 14 No. 2 Article 84
High-dimensional tabular data are common in biomedical and clinical research, yet conventional machine learning methods often struggle in such settings due to data scarcity, feature redundancy, and limited generalization. In this study, we systematically evaluate Synolitic Graph Neural Networks (SGNNs), a framework that transforms high-dimensional samples into sample-specific graphs by training ensembles of low-dimensional pairwise ...
Added: May 23, 2026
Kibkalo Vladislav, Chertopolokhov V., Mukhamedov A. et al., IEEE Access 2026 Vol. 14 P. 14369–14392
This study presents on-the-fly identification and multi-step prediction of nonlinear systems with delayed inputs using a dynamic neural network combined with a smooth projection onto ellipsoids. The projection enforces parameter constraints that guarantee stability, while a Lyapunov–Krasovskii analysis yields computable ultimate error bounds. Riccati-type matrix inequalities are derived, providing an efficient vectorization–projection–devectorization implementation suitable for ...
Added: May 22, 2026
Морозов С. В., Calcolo 2026 Vol. 63 No. 2 Article 23
The approximation of tensors in a low-para metric format is a crucial component in many mathematical modelling and data analysis tasks. Among the widely used low-parametric representations, the canonical polyadic (CP) decomposition is known to be very efficient. Nowadays, most algorithms for CP approximation aim to construct the approximation in the Frobenius norm; however, some ...
Added: May 22, 2026
Селянин Ф. И., Journal of Dynamical and Control Systems 2026 Vol. 32 No. 2 P. 1–16
A B-facet is a lattice -dimensional polytope in the positive octant with a positive normal covector, such that every -dimensional simplex with vertices in it is a B-simplex (i.e., a pyramid of height one with base on a coordinate hyperplane). B-facets were introduced in [2] in the context of the monodromy conjecture. In this paper, we complete the ...
Added: May 21, 2026
Ausubel L., Baranov O., Journal of Economic Theory 2026 Vol. 235 No. 106192
The Vickrey-Clarke-Groves (VCG) mechanism is one of the most compelling constructs in mechanism design, but the presence of complementary goods creates the possibility of non-core and even zero-revenue outcomes. In this article, we show that joint feasibility constraints on allocations offer a second pathway to ill-behaved outcomes in the VCG mechanism, even when all bidders ...
Added: May 20, 2026
Denis Seliutskii, Russian Journal of Mathematical Physics 2025 Vol. 32 No. 2 P. 399–407
In this paper, we find an upper bound for the first Steklov eigenvalue for a surface of revolution with boundary consisting of two spheres of different radii. Moreover, we prove that, in some cases, this boundary is sharp. ...
Added: May 19, 2026
Жакупов О. Б., European Journal of Mathematics 2025 Vol. 11 Article 84
We provide examples of smooth three-dimensional Fano complete intersections of degree 2, 4, 6, and 8 that have absolute coregularity 0. Considering the main theorem of Avilov, Loginov, and Przyjalkowski (CNTP 18:506–577, 2024) on the remaining 101 families of smooth Fano threefolds, our result implies that each family of smooth Fano threefolds has an element of absolute ...
Added: May 18, 2026
Gonchenko S., Lerman L., Turaev D., Regular and Chaotic Dynamics 2026 Vol. 31 No. 3 P. 349–369
We show that bifurcations of four-dimensional symplectic diffeomorphisms with a quadratic homoclinic tangency to a saddle periodic orbit with real multipliers produce 2-elliptic periodic orbits if the tangency is not partially hyperbolic. We show that a normal form for the rescaled first-return maps near such tangency is given by a four-dimensional symplectic H´enonlike map and study bifurcations of the ...
Added: May 15, 2026
Aleskerov F. T., Khutorskaya O., Stepochkina A. et al., Springer, 2026.
The book contains new models of bibliometric analysis based on centrality measures in network analysis, pattern analysis and stability analysis. A distinctive feature of these centrality measures is that they account for the parameters of vertices and group influence of vertices to a vertex. This reveals specific groups of publications, authors, terms, journals and affiliations ...
Added: May 15, 2026
Kuptsov P., Panyushev A., Stankevich N., Chaos 2026 Vol. 36 No. 5 Article 053138
We develop a machine-learning approach to reproduce the behavior of two versions of the van der Pol oscillator exhibiting a subcritical Andronov–Hopf bifurcation, with or without a codimension-2 Bautin point. We construct a neural-network model that functions as a recur rent map and train it on short segments of oscillator trajectories. The results show that, ...
Added: May 15, 2026
Dorovskiy A., / Series arXiv "math". 2026.
In this paper the structural stability of generic families of vector fields of the PC-HC class on the two-dimensional sphere is proved. A classification of these families up to moderate equivalence in neighborhoods of their large bifurcation supports is presented, based on such invariants as the configuration and the characteristic set. The realization lemma is proved. ...
Added: May 14, 2026
Lebedev V., Journal of Mathematical Analysis and Applications 2026 Vol. 563 No. 2 Article 130787
It is known that for every continuous real-valued
function $f$ on the circle $\mathbb T=\mathbb R/2\pi\mathbb Z$ there exists a
change of variable, i.e., a self-homeomorphism $h$ of $\mathbb T$, such that
the superposition $f\circ h$ is in the Sobolev space $W_2^{1/2}(\mathbb T)$.
We obtain new results on simultaneous improvement of functions by a single
change of variable in relation ...
Added: May 14, 2026
Blokh A., Oversteegen L., Selinger N. et al., Arnold Mathematical Journal 2026 Vol. 12 No. 1 P. 60–110
We describe a model for the boundary of the connectedness locus of the parameter space of cubic symmetric polynomials. We show that there exists a monotone continuous function from the connectedness locus to the model which is a homeomorphism if the former is locally connected. ...
Added: May 13, 2026
Petrov I., Автоматика и телемеханика 2026 № 6 С. 82–118
Системам связанных агентов и сетевому управлению посвящено большое число отечественных и зарубежных исследований. Исторически, наибольший интерес в теории управления возникал к усредняющим системам и, в частности, к задаче консенсуса. Однако сетевое взаимодействие может характеризоваться более специфическими функциями, отражающими зависимость от действий соседей по сети, что особенно явно проявляется в моделях стратегического взаимодействия на сети, которое ...
Added: May 12, 2026
Салагай О. О., Сахарова Г. М., Антонов Н. С. et al., Общественное здоровье 2024 Т. 4 № 4 С. 4–15
Introduction. The study is devoted to the analysis of the dynamics of the tobacco and alcohol use prevalence among the adult population during the COVID-19 pandemic.
The purpose of the study: to analyze the impact of the COVID-19 pandemic on the prevalence of tobacco and nicotine-containing products consumption among the adult population of the Russian Federation, men and ...
Added: April 9, 2026
Салагай О. О., Сахарова Г. М., Антонов Н. С. et al., Общественное здоровье 2022 Т. 2 № 2 С. 29–39
The fight against the COVID‑19 pandemic has led to the implementation of unprecedented measures in countries, including self-isolation, which have had a significant impact on people’s behavior and could lead to a change in the consumption of tobacco and nicotine-containing products. This article provides an overview of studies evaluating smoking behavior change and its impact ...
Added: April 9, 2026
Islentyeva Anna, Scheffler T., Discourse and Communication 2024 Vol. 18 No. 2 P. 216–243
This paper represents a comparative study that explores the governmental vaccine advertising campaigns that were authorised by two English-speaking and two German-speaking countries – namely Australia, Britain, Austria and Germany – within the context of the global SARS-CoV-2 pandemic. The data set in question comprises 40 vaccination posters issued by each country’s respective government between ...
Added: March 9, 2026
Bilqis L. C., Shishkina A., Journal of Globalization Studies 2025 Vol. 16 No. 2 P. 169–179
This article is devoted to the study of the phenomenon of digital nomadism in the period after the onset of the COVID-19 pandemic, which has accelerated the trend on transformation of many aspects of life, including labor market, due to digitalization. The authors discuss the significance of this phenomenon in the context of the intensified ...
Added: February 25, 2026
Semenova M., Loginova Y., Balsevich A. A., Pacific-Basin Finance Journal 2026 Vol. 97 Article 103118
This paper examines the effect of board gender diversity on bank performance during the COVID-19 crisis. Using a panel dataset of 173 European banks spanning the period 2010–2022, we find that the presence of female directors on bank boards is positively associated with profitability and solvency during the pandemic period. The positive impact is more ...
Added: February 22, 2026
Orlando G., Bufalo M., Nazarova V., Population Health Metrics 2025 Vol. 23 Article 71
The COVID-19 pandemic has disproportionately impacted vulnerable populations, such as low-income households, exacerbating existing health and economic challenges. In Cuba, the crisis exposed the effects of long-standing economic difficulties, worsened by sanctions, but the country’s robust public health system and independent vaccine development enabled an effective response. This study addresses the gap in understanding how ...
Added: February 3, 2026
Volkovskii D., Olga Filatova, , in: 26th Annual International Conference on Digital Government Research (dg.o 2025). Volume 26Vol. 26.: Delft: [б.и.], 2025.
Deliberation is a basic term about reaching a decision through balanced discussion, which openly raises the issues of consensus and its achievement through communication. The current article aims at studying the quality of online deliberation between citizens and Russian authorities on social media in the conditions of global health crisis COVID-19. Indeed, the quality of ...
Added: January 25, 2026
Monahhova E., Morozova A., Bredikhin D. et al., Neuroimage 2026 Vol. 327 Article 121727
Advances in deepfake technology raise concerns about disinformation spread. Novel deepfake technologies make it increasingly difficult to distinguish between real and fake media content. The current study investigated how speakers’ credibility, the participants’ traits and attitudes may influence the brain processing of audio deepfakes arguing for and against COVID-19 vaccination. We analyzed the electroencephalograms (EEGs) ...
Added: January 16, 2026