This study conducts a comprehensive bibliometric analysis of binary logistic regression research spanning from 1974 to 2024. It examines 15,409 documents authored by 77,557 researchers across 137 countries and published in 4,669 different sources. The results reveal a strong and sustained annual growth rate of publications, with a marked surge after 2010, and a global shift toward interdisciplinary applications. China leads in volume of publications (10,553 articles), while the United Kingdom and the Netherlands demonstrate the highest citation impact (approx. 23.5 citations per article). Ethiopia emerges as a notable contributor from the Global South, with more than 8,000 publications. At the journal level, PLOS One and BMC Public Health stand out as the most prolific outlets, whereas the works of Hosmer and Lemeshow remain the most influential references in the field. Thematic mapping highlights clusters in public health, epidemiology, and artificial intelligence, underscoring the central role of binary logistic regression in both methodological and applied domains. These findings provide a panoramic view of the field, highlighting key contributors, trends, and opportunities for future research. The analysis was performed using R-4.4.1 and VOSviewer 1.6.20 software.
Vector autoregressive (VAR) models are used to capture the dynamic relationships among multivariate time series. On the other hand, multivariate stochastic volatility (MSV) models allow modeling the variance as it changes over time. Student’s t-distribution is used to model extreme values in time series. Therefore, this article proposes the integration of a VAR model, an MSV model, and a Student’s t-distribution (VAR-MSV-t). The selection of the most appropriate VAR-MSV-t order is carried out using the Deviance Information Criterion (DIC). Formulas are presented to estimate the Mardia skewness and the Koziol kurtosis of the model. The model is applied to three key macroeconomic variables for the United States. The S&P 500 stock market index is added, and the results are interpreted. Parameter estimation is carried out using Markov chain Monte Carlo (MCMC) methods. The results indicate that the model effectively captures the dynamic relationships, time-varying variance, and extreme magnitude values.
The objective of this review article is to synthesize and present, in a detailed manner, the technique of specialization of curves. Specifically, we review and analyze key examples on how certain curves of degree 4 and arithmetic genus 0 (parametrized by the Hilbert scheme Hilb4m+1(ℙ3)) can transform or degenerate into other curves. The computational calculation procedure is detailed and illustrated through the use of the Macaulay2 software. Finally, the utility of specializations for explicitly describing and classifying the irreducible components of Hilbert schemes and their corresponding Chow varieties is evaluated. The technique of specialization of families of curves has established itself as a powerful and rigorous method in algebraic geometry. By providing a well-defined stratification diagram, this tool allows for a precise classification of curves and an understanding of the connectivity of the components of the Hilbert scheme.
In this work, we present a concise and educational study of gravitational lensing by transparent matter distributions. We focus on the calculation of image properties for several idealized mass profiles, including the uniform transparent sphere, the isothermal gas sphere, the non singular isothermal sphere, and the transparent King profile. Using numerical techniques and the XFGLenses software, we compute and visualize the resulting lensed images, along with the associated critical curves and caustics. The results are consistent with established theoretical predictions for transparent lenses, for example, the occurrence of an odd number of images, and the reduction of two images as the source crosses a caustic. The caustic geometries observed include diamond-shaped, elliptical, and lemniscate-like structures. Among the critical curves, ellipses were most commonly observed, while lemniscatelike forms emerged specifically in the transparent non-singular isothermal sphere case, in agreement with known behaviors in gravitational lensing by smooth matter distributions.
This article presents a construction in the category of symmetrical operads in differential graded modules, which takes an operad defined in a sub S -module and extends it to an operad, whose underlying S -module includes the original. We call this the polynomial operad. This construction depends on the existence of colimits on the category of operads so a detailed review of this result is included.
We present analytical solutions for a universe with a scalar field equivalent to a mixture of three perfect fluids: dark energy, dust and stiff matter. The space-time is an anisotropic and homogenous universe of Petrov Type D that expands isotropically in two spatial axes. We also determine the singularities with the Kretschmann scalar, the Hubble parameter, the deceleration parameter, and the temperature in terms of time. Finally, we study the Jacobi stability of the universe with the scalar field and conclude that the model is stable at all times.
En este estudio se selecciona un espacio físico con geometría rectangular y se realiza un análisis comparativo entre los parámetros acústicos generados a partir de la medición in situ de sus respuestas impulsionales, utilizando un parlante unidireccional y los parámetros acústicos obtenidos a partir de métodos numéricos en un programa de simulación, donde se utiliza un parlante omnidireccional como fuente de sonido. Se evalúa también el posible beneficio de aproximar una fuente sonora onmidireccional mediante la rotación de una fuente unidireccional en el plano horizontal. Los resultados obtenidos indican que las mediciones realizadas con el parlante unidireccional permiten obtener una caracterización general de la acústica del espacio, con niveles de error que podrían ser tolerados, sobre todo a frecuencias medias, con la ventaja de tener un costo menor.
This article introduces a two-level overlapping additive Schwarz algorithm tailored for solving elliptic problems discretized with the symmetric interior penalty discontinuous Galerkin method. The proposed algorithm allows for the use of irregular subdomains, overcoming limitations of other approaches where the coarse mesh was based on triangular elements. Additionally, we provide a brief description of the numerical implementation of the Galerkin method. We present numerical results validating the relevance of our algorithm, including cases where the coefficient of the differential equation is discontinuous—a feature that is particularly relevant to various practical applications.
Telecommunications is currently one of the most important technologies, utilizing various infrastructure elements to enable communication over the Internet. When an internet connection is established, traffic packets are routed from one device to another, taking different paths through routers that process each packet. These networks present multiple challenges in processing, distributing and connecting traffic. To address these challenges it is necessary, on the one hand, to have models that describe the behavior of traffic and its evolution over time, such as the Generalized Markov Fluid Model. On the other hand, it is essential to reserve part of the available resource at each node for ongoing connections. To carry out this reservation process, the Effective Bandwidth is employed. In this paper, we describe the distribution of the buffer in equilibrium for traffic sources modeled by a Generalized Markov Fluid Model, using a system of differential equations. As the main result of this paper, we prove that it is possible for this model to characterize the effective bandwidth when the most probable duration of the buffer busy period prior to overflow becomes larger and larger. Finally, we verify this result numerically from simulated traffic traces.
In this paper, we present a robust stability criterion for a heat equation with axial symmetry and with a general time-conformable fractional derivative defined on a sphere. The heat equation is assumed to have a heat source that is represented as a Fourier series with coefficients described by bounded, piecewise continuous functions. The robust stability criterion establishes conditions to guarantee that the solution of the heat equation, along with its partial derivative with respect to the radial axis and its general timeconformable fractional derivative, remains bounded by a predetermined value. The robust stability criterion is obtained by extending the concept of stability under constant-acting perturbations applied to systems of ordinary differential equations. The results are illustrated numerically.
En característica prima, el umbral F-puro es un invariante numérico que mide singularidades. Se conocen pocas estimaciones de este número. En esta nota, calculamos explícitamente el umbral F-puro del ideal homogéneo máximo en un anillo de Stanley-Reisner y demostramos que este número y la dimensión de escisión son iguales.
Unsupervised learning techniques are employed to study the relationship between atmospheric circulation and precipitation over Central America and its surrounding areas. Specifically, the clustering algorithm k-means++ is applied to three coarse-grained datasets from ERA-interim reanalysis that are the candidates for representing the atmospheric state vector, each candidate contains its full temporal variability. Datasets are composed of: a) wind fields at 925, 800 and 200 hPa, b) same as “a)” plus convective available potential energy and c) same as “a)” plus total column water vapor. Clustering metrics, namely the variance ratio criterion, the silhouette criterion and the mean squared error, are computed to quantify clustering quality. Clusters are interpreted as weather types, recurrent configurations of the atmospheric state vector associated with observable weather states. The correct number of clusters for each dataset is determined with a Monte Carlo test of normality, to assure cluster existence. The main objective is to obtain a set of weather types containing elements that characterize the transition from and to the rainy season over the Pacific side of Central America as well as other elements of the seasonal cycle of regional precipitation, such as the Mid-Summer Drought. Besides the statistical metrics, in order to select between candidate datasets and plausible number of clusters, focus is given to the temporal characteristics of the clusters. Existing literature does not provide a set of weather types suitable to analyze seasonal transitions and the differences in the mechanisms associated with rainfall maxima.
El modelo GARCH (modelo autorregresivo condicional heterocedástico generalizado) es un modelo estadístico para series de tiempo usado para describir la varianza del error como una función de los errores al cuadrado pasados y de las varianzas. Estos modelos GARCH son usados para modelar la volatilidad variando en el tiempo y los clusters de volatilidad. Si además el efecto de la varianza es incluido en las observaciones para predecir la media, se tiene un GARCH-M (GARCH en media). En este artículo, se analizan estos modelos en un contexto bayesiano para series de tiempo bivariadas, donde las observaciones son asumidas de comportarse como un modelo VAR-GARCH-M. Una aplicación del modelo bivariado es ajustado para medir el efecto de la variabilidad de la inflación y crecimiento del producto en la media de la inflación y crecimiento del producto.
A finales de los años 70, el término análisis de Clifford fue empleado por primera vez por el matemático norteamericano John Ryan. Han pasado varias décadas y esta autónoma disciplina en el análisis matemático resulta sumamente efectiva para reescribir muchas de las ecuaciones de la física matemática. En el presente artículo se obtendrán algunos resultados interesantes sobre operadores lineales que se relacionan con espacios funcionales que surgen específicamente en álgebras de Clifford. La conexión de algunos de estos operadores con el conocido sistema de Lamé-Navier en elasticidad lineal posibilita que se estudien propiedades esenciales y generalizaciones naturales a altas dimensiones. Al finalizar, se considerarán nuevos operadores de Dirac construidos con bases ortonormales arbitrarias del espacio euclidiano.
Despite their widespread use in advanced analytical and numerical techniques, gradient field methods are often underrepresented in the foundational training of economists and social scientists. As machine learning and sophisticated analytical and numerical approaches gain traction, the importance of gradient methods in optimization processes becomes increasingly apparent. This oversight in academic and practical toolsets is suboptimal. This paper aims to address this gap by introducing gradient field methods both intuitively and rigorously, situating them within the context of problems commonly encountered by economists and social scientists, with a particular focus on equality constrained optimization.
El uso de wavelets adaptadas para el reconocimiento de patrones es muy atractivo por la multiescalaridad de la transformada wavelet. Sin embargo, el buen desempeño de estos algoritmos en la detección de patrones depende fuertemente de la construcción de los filtros adaptados al patrón de interés. La Transformada Shapelet Discreta II [9] (DST-II) es un algoritmo inspirado en la transformada wavelet, que permite el diseño de filtros a la medida para la detección de patrones en señales unidimensionales. La construcción de estos filtros requiere la solución de un sistema de ecuaciones no lineales, que según [9] se puede efectuar mediante cualquier método iterativo. Esta investigación presenta un novedoso y exhaustivo estudio numérico que demuestra el impacto de la elección del método numérico adecuado para la solución del sistema no lineal en la DST-II. La eficacia de los filtros estimados repercute en el desempeño de esta transformada en la detección de patrones. Los mejores resultados se obtienen al combinar el método de Newton con preiteración mediante el algoritmo de continuación. La convergencia alcanzada para el 55, 37% de los patrones sugiere que la DST-II podría ser adecuada para patrones con formas específicas, de utilidad en aplicaciones sobre señales biomédicas.
Este trabajo presenta un resultado sobre unicidad para problemas de cuasiequilibrio (QEP), que no requiere de la hipótesis de Hölder continuidad, que según nuestro conocimiento es la hipótesis sobre el cual se ha garantizado unicidad para QEP hasta la actualidad. La idea básica de nuestro enfoque consiste en iniciar con un QEP simple, por ejemplo un problema de equilibrio (EP), que denotaremos por QEP(t0) con t0 ∈ [0, 1), del cual asumiremos unicidad de la solución, bajo algunas condiciones suficientes de no-singularidad dadas por nuestras hipótesis garantizamos la existencia de un camino continuo de soluciones únicas de QEPs parametrizados que empiezan en la solución del QEP(t0) y finalizan en la solución del QEP(1) que es el QEP original. Finalmente estudiamos estas condiciones basadas en cierto tipo de matrices, para casos particulares de QEPs que son populares en la literatura.
First-mile problems have become a major problem for the automobile industry since moving cars from production plants to selling destinations is characterized by using vehicle carriers with limited space. Although supply chain processes have automatized last-mile operations to improve productivity and increase benefits, first-mile analysis has been widely ignored. For example, in the automotive industry, cars are stored in parking lots until they are demanded, which negatively impacts delivery times and increases transportation costs. The previous issues impact the first-mile logistics of the automobile industry to the detriment of copying with delivery times and increasing the operation cost. In this paper, we deal with the previous issues by modeling the movement of cars from the parking lot to the car Carrier as an optimal control problem. Considering that not all cars should leave the parking lot, we search for conditions that guarantee the existence of a unique optimal path when the cars’ requisition is uncertain. Theoretical results provide a closed-form solution that indicates the optimal path to fill the car carrier in a time window. Such solutions allow us to study the impact of exogenous parameters (such as the parking lot size, the starting point, andmarginal costs) on the behavior and features of the optimal path.
En este artículo de recolección e investigación se estudia la propagación de ondas ultrasónicas en líquidos con burbujas de gas. Estos medios son extremadamente no lineales, una pequeña fracción de vacío cambia drásticamente las propiedades acústicas del medio. Las burbujas de gas no solo producen una alta no linealidad, sino que también producen fenómenos de dispersión y atenuación que son muy importantes para el comportamiento ultrasónico. Se presentan aquí varios resultados obtenidos mediante un modelo numérico desarrollado previamente (basado en el método de los volúmenes finitos en la dimensión espacial y en el método de las diferencias finitas en el dominio temporal) que permite analizar algunos efectos complejos asociados a este problema. El modelo resuelve un sistema diferencial que acopla las oscilaciones no lineales de las burbujas y el campo acústico. Nos centramos principalmente en entender como potenciar la generación de nuevas frecuencias (armónicos y subarmónicos a partir de una fuente de una frecuencia y frecuencias suma y diferencia a partir de una fuente de dos frecuencias) teniendo en cuenta algunos aspectos como el tipo de cavidad, el suavizado y optimización del medio.
This expositive paper aims at the study of nonlinear equations, focused on the van der Pol equation, including deduction, qualitative analysis, and numerical examples. The van der Pol equation is deduced using an electrical circuit as a physical model. The qualitative analysis is divided into two parts: the theoretical enunciation and its application. The main theorems used in this study are Poincaré-Bendixson’s and Lyapunov’s. The construction of a Lyapunov function is also performed. Finally, a series of numerical examples are graphically presented using computational tools such as Python and Octave. The phase portraits and temporal behavior of the van der Pol equation are exhibited, along with the basin of attraction obtained experimentally, compared with the basin of attraction yielded by the Lyapunov function. Therefore, the numerical study provides a visual representation of the results stated in the qualitative analysis
