bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Discrete Odd Lindley Half-Logistic Distribution with Applications
Authors: Shamlan D , Baaqeel H , Fayomi A 
Published: February 2024

Abstract
In the reality, the most of lifetime data is discrete in nature, despite it is known that this data is continuous. As a consequence, the tendency to convert the continuous lifetime distributions to its discrete counterpart has raised. The nature of the most lifetime data in real life is discrete, thus, many of researchers interested to convert. This article aims to introduce a new one-parameter discrete distribution, namely Discrete Odd Lindley Half-Logistic (DOLiHL) distribution. The DOLiHL distribution is derived by discretizing the analogue continuous distribution, using a survival discretization technique. An intensive study of this distribution is provided, including characteristic functions and statistical properties. Moreover, the unknown parameter is estimated using different methods of estimation namely, the maximum likelihood method, method of moments, least squares method and Cramer-von Mises minimum distance estimation method. A simulation study is conducted to examine the distribution’s behavior and compare between the estimation methods at different sample sizes. To evaluate the efficiency of this distribution against other competitive distributions, an implementation on real data in different fields is performed. In conclude, the DOLiHL distribution has assured its efficiency of fitting in lifetime and count data from various fields in real life.
Arithmetic modeling of k-ary n-cubes and toroidal k-ary grids
Authors: Roig Pedro J. , Alcaraz Salvador , Gilly Katja , Bernad Cristina , Juiz Carlos 
Published: February 2024

Abstract
The use of toroidal topologies offers many advantages in the computing field when it comes to both pattern spotting and path finding strategies. The former is covered by de Bruijn shapes, which permit to uniquely locate a single pattern throughout the shape. However, the latter is mainly carried out by k-ary n-cubes, which label node identifiers in a sequential order according to rows, columns, layers, and so on. This scheme facilitates the movement among nodes by just applying arithmetic operations, such as integer divisions and arithmetic modulo n. On the othe hand, toroidal k-ary grids are an alternative available in some specific cases, where determined patterns appear in all dimensions of each node, thus allowing to use those patterns to dictate paths to move among nodes. In this paper, the arithmetic bases of both path finding strategies have been presented and some pseudocode algorithms have been designed.
Numerical study of the “two components” model and background effects in muonic hydrogen experiments
Authors: Danev P , Tonchev H , Boradjiev I , Stoilov M 
Published: February 2024

Abstract
In this study, we explore the X-ray time spectra of muonic oxygen in various H
2 + O
2 gaseous mixtures by means of numerical simulations based on a sophisticated kineticrate equations model. Our primary focus is on the “two components” hypothesis, which was put forward to account for the experimentally observed two successive exponential behaviors in the radiation time-distribution. To ensure an accurate representation of the physical processes in the experiments, we incorporate precise transition rate coefficients for the elastic and inelastic scattering between the muonic hydrogen atoms and other gas constituents, in our simulation code. Specifically, a crucial aspect in our approach is the utilization of the energy dependence of the muon transfer rate to oxygen, recently extracted from experimental data by the FAMU collaboration. The accurate knowledge of such muonic oxygen X-ray time spectra is vital for cutting-edge experiments like FAMU, where the hyperfine splitting in muonic hydrogen atoms is to be determined with high accuracy, as this time spectra serves as a significant part of the background for the desired signal.
A high order method for oscillatory delay differential equations
Authors: Luca Liliana , Ricciardello Angela , Ruggieri Marianna 
Published: February 2024

Abstract
This paper addresses the oscillatory properties of a class of second-order neutral delay differential equations (NDDEs) and introduces a numerical scheme based on a fourth-order predictor-corrector multistep method for solving NDDEs of this type. An example in the family of oscillatory equations has been integrated by using the proposed numerical scheme. Results confirm the theoretical assumptions.
Random Fourier Surrogate for simulation calibration
Authors: Mahyub M , Souza LS , Batalo B , Yamazaki K 
Published: February 2024

Abstract
In this paper we propose Random Fourier Surrogate (RFS) as a method for simulation calibration. Computer simulations are actively used in various fields to model and analyze complex real-world phenomena, enabling practitioners to explore situations inaccessible by other means. To create a simulation that accurately reflects the desired real-world scenario requires calibrating the simulation parameters, a non-trivial process that requires domain expertise and iterative trial-and-error. The model-bridge paradigm has been proposed to automatize this process, where a more computationally efficient surrogate model is used in lieu of the real simulation, and a bridge model is used to map the noninterpretable surrogate parameters to calibrated simulation parameters, which are physically interpretable. Recently an efficient solution called tangent slope-intercept (TSI) descriptors has been proposed, where tangent lines of a principal curve are used to represent the simulation in low dimensionality. However, we find that it has two key problems: it is prone to overfitting and is sensitive to initialization. We address these issues using Random Fourier Features to construct a surrogate model, thereby reducing calibration time by avoiding complex computations, while retaining high accuracy. We evaluate the effectiveness of our method with different experiments on synthetic signal simulations and physical simulations of turbulent flow dynamics.
Multiscaled inviscid Taylor-Green vortex flow for examining energy conservation error in incompressible flows
Authors: Gong Xuanyou , Suzuki Hiroki , Kouchi Toshinori 
Published: February 2024

Abstract
This study investigates kinetic energy conservation errors in incompressible flows using multiplexed inviscid Taylor-Green vortices. Fourth-order precision Runge-Kutta methods, specifically five- and six-step methods, were employed and an inviscid two-dimensional periodic flow field was used as a test case. This method allows the energy conservation error to be suppressed to a very low level. Recent previous studies have dealt with turbulence generation using a multi-scale turbulence grid. In this study, the Taylor-Green vortex of the analytical solution is multiplexed to generate a flow field with a number of wavenumbers. Visualisation results of the initial field and the energy distribution over time were obtained. It was observed that the errors in the time evolution of the fluid energy were extremely small, and that the errors actually increased with time. However, the influence of the time step range was limited and the analytical and numerical solutions were in general agreement. As a result, it was confirmed that the inviscid Taylor-Green vortex is effective in examining the energy conservation error for incompressible flows.
Simulation of the Knudsen Pump by means of Quasi Gasdynamic Equation System
Authors: Kudryashova T A , Polyakov S V , Shilnikov E V 
Published: February 2024

Abstract
The use of miniature micropumps based on the effect of thermal gas sliding along the walls with an applied temperature gradient (Knudsen pump) is very relevant when creating modern miniature devices. Currently, algorithmically complex methods such as DSMC are usually used to simulate gas flows in such pumps. Progress in the development of algorithms based on a quasi-gasdynamic system of equations, pushed the authors to apply such algorithm to modeling the flow of a binary gas mixture gases in one variant of a micropump. The equations of the QGD system are conservation laws with additional dissipative terms. These terms contain a coefficient determined by the characteristic time between particles collisions. In this paper, the problem of flow in a rectangular Knudsen pump is solved based on this algorithm for a gas mixture in a single-fluid approximation. Different variants of the composition of the gas mixture are considered. The Knudsen numbers for which it is possible to describe gas flows by the QGD system correspond to flows of dense or moderately rarefied gases. Calculations for not too large Knudsen numbers demonstrated a good agreement with the results obtained by the DSMC method which is much more complex and expensive.
Non-linear response of kinetic energy in an inviscid Taylor-Green flow obtained by OpenFOAM-LES with respect to time increments
Authors: Ono Akira , Suzuki Hiroki , Kouchi Toshinori 
Published: February 2024

Abstract
This study investigates the conservation error of kinetic energy with respect to time increment using OpenFOAM LES. The energy conservation error is verified using an inviscid Taylor-Green vortex and the effect on energy conservation is checked by varying the time increment by a factor of 30. Differences in the response of turbulent energy conservation between large and small time increments are also verified. Higher order accuracy for time increments is expected when the kinetic energy conservation accuracy is high, however the actual behaviour in OpenFOAM needs to be investigated: as the implicit time integration method is used in OpenFOAM, a non-linear response is expected. As a result, it is evident that kinetic energy is not fully conserved in the inviscid flow of OpenFOAM. The kinetic energy distribution is similar for different time increments, with a different relationship between the conservation error observed in the range of large and small time increments.
Experimental validation on a calibration position of a hot-wire anemometer for measuring multi-scale grid-generated turbulence
Authors: Yamaguchi Hiroto , Suzuki Hiroki , Kouchi Toshinori 
Published: February 2024

Abstract
This study aims to experimentally examine conditions that should be satisfied by a calibration position of a constant-temperature hot-wire anemometer. Specifically, this study addresses an appropriate measurement point when this calibration is performed downstream of a turbulent field generated by a multi-scale turbulence grid. The hot-wire measurement in this study is based on an I-type probe with a standard 5 μm tungsten wire. The hot-wire anemometer in this study is small and can be attached to a probe support. In this study, uncertainty in the calibration curve of the hot-wire measurement is first checked. Here, Pitot tube velocimetry to obtain the calibration curves is carried out using two bell-type micro-differential pressure gauges. Then, the characteristics of the obtained velocity fluctuations and turbulence will be examined. Based on this relative velocity fluctuation RMS value, the effects of the obtained streamwise velocity fluctuation on output voltage are obtained by asymptotically expanding a calibration curve. Using these results, the intensity of the free-stream turbulence, which has a negligible effect on output voltage giving a calibration curve, is clarified.
On stable and quasi-chaotic regimes in a one-dimensional unimodal mapping obtained by modeling the dynamics of a biological population
Authors: Polyanovsky V O , Kamenev I G 
Published: February 2024

Abstract
The paper considers the properties of the difference equation describing the dynamics of the animal population, obtained earlier in the framework of studies of tundra communities. We have considered a special case in which the model is represented by a one-parameter difference equation that defines a one-dimensional unimodal mapping of a segment into itself, similar to the well-known triangular (tent) mapping, supplemented by a region with a constant value. A change in the mapping parameter generates a bifurcation scenario, in which stability zones arise, characterized by orbits of a constant period, interspersed with zones with more complicated, “quasi-chaotic” regimes. Based on the properties of the n-iterated triangular mapping, a necessary and sufficient condition for the localization of cyclic orbits in the considered type of unimodal mappings is formulated, which makes it possible to identify stability regions for any given period n. On the basis of this condition an algorithm for detecting stability zones is proposed. The main subject of the study is the fractal properties of the set, which is the complement of the obtained set of stability regions to the entire domain of mapping definition. The dynamics of the DH
(n) value is obtained, the limit of which at n → ∞ is equal to the fractal dimension dH
. It is shown that in the studied range of n (2 ≤ n ≤ 22), the DH
(n) < 0.9, which suggest that dH
< 1. If so, then according to the definition of a fractal set, its topological dimension is dT
= 0, which means that the complement of the set of stability regions consists of isolated points.
Equivalent Radius for Well Inflow Calculations at Different Regimes in Reservoir Flow Simulations
Authors: Zhaglova Anna E , Ibragimov Akif I , Indrupskiy Ilya M , Zakirov Ernest S , Anikeev Daniil P 
Published: February 2024

Abstract
A problem of well representation in numerical simulation of fluid flows in porous media is considered. When modelling hydrocarbon reservoirs, underground gas storages and other natural porous media, there’s a large typical difference in scales of wells (about 10 cm) and inter-well distances (from hundreds to thousands meters), so wells aren’t resolved on the grid as explicit boundaries in large-scale reservoir simulations. Instead, wells are represented by sources/sinks. The problem is that the average pressure in a grid block containing the well (well block pressure, WBP) isn’t equal to the well pressure (bottomhole pressure, BHP). D. Peaceman showed that WBP can be interpreted as the pressure at equivalent radius inside the well grid block. He derived the classical formula for the equivalent radius for steady-state (SS) Darcy flow. Though Peaceman showed it could be used for pseudo steady-state (PSS) flow as well, his derivation for PSS was not accurate. In this paper we compute the equivalent radius for PSS and boundary dominated (BD) regimes of Darcy flow and examine the impact of flow regime and distance to external boundary (or inter-well distance) on it. The results are important for accurate well representation in numerical flow simulations of underground reservoirs.
Justification of Urgent Brain CT scans at Palestinian Government Hospitals
Authors: Nazzal Anas , Ahmad Muntaser S. , Mohammad Hjouj 
Published: February 2024

Abstract
CT In cases of mild brain injury emergencies, CT scans can be valuable. However, misuse can result in radiation exposure and increased costs. This study examines CT scan utilization in Palestinian government hospitals, using a comprehensive multi-hospital analytical approach. It involved 66 emergency doctors and residents from Darwish Nazzal, Al Hussein, and Palestine Medical Complex. Findings indicate disparities in CT scan ordering practices among emergency physicians. Only 33.3% adhere to recommended guidelines, while 10.6% request scans for non-medical reasons. A lack of awareness regarding radiation exposure is seen in 39.4% of clinicians. Moreover, there are variations in image interpretation and ordering practices between morning and night shifts. Cost concerns are expressed by 68.2% of doctors, and 14.5% of CT scans were unjustified, often due to vague requests. This study underscores the importance of educating clinicians on radiation risks and promoting adherence to current CT scan criteria. Local guidelines and checklists are needed to justify CT scans, and physicians should participate in seminars on radiation doses and maximum allowable levels to reduce unnecessary scans. The hiring of night-shift radiologists in public hospitals is also recommended to enhance patient records and reduce costs.
Electro-mechanical analogy for Prabhakar-like fractional viscoelasticity
Authors: Colombaro Ivano , Arnone Giuseppe 
Published: February 2024

Abstract
The aim of this paper is to set up a formal equivalence between a mechanical system and an electrical one. Specifically, we consider the Maxwell-Prabhakar linear viscoelastic model, based on Prabhakar fractional operators. Therefore, we find the analogous expression for the electric current due to a step potential. The expression for the resulting electric current depends on the variable characterizing the viscoelastic model and its behaviour is then discussed with the support of some interesting plots.
Evaluation of location-data based features using Gaussian mixture models for age group estimation
Authors: Kakimoto Yohei , Omae Yuto 
Published: February 2024

Abstract
Several studies have estimated the demographics and behavioral patterns of users of mobile devices, such as smartphones, using a variety of information obtained from such devices. However, most studies have estimated unknown demographics by correlating the geographical information of users with their mobile device usage histories and social networks. In such cases, significant costs are incurred in preprocessing the data before building an estimation model. Therefore, in this study, we verified whether user demographics can be estimated using only location data obtained from mobile devices. We constructed a machine-learning model that classifies user age groups into two classes, young and elderly, based on the input features generated from location information using a Gaussian-mixture model. By measuring the classification performance of the constructed model, we confirmed that location information contained the information necessary for user attribute estimation. Experimental results confirmed that the classification model constructed based on location information exhibited high classification accuracy for the two classes of equally sampled age groups. These findings indicate that location data contain the necessary information for estimating user demographics.
SIMBAD: a simplified emission-concentration model for a computationally efficient assessment of energy policies impact on air quality
Authors: Paolo Costa Matteo , De Angelis Elena , Pirovano Guido 
Published: February 2024

Abstract
The reconstruction of airborne pollutant concentration fields based on emission reduction scenarios is a complex task. Simulations with chemistry and transport models (CTM) are computationally expensive and not suited for iterative optimisation that could require the evaluation of a great number of scenarios. To address this, data-driven surrogate models have been used to approximate the relationship between emission and ambient air concentrations. In this study, a different approach is presented. SIMBAD is a simplified model based on CAMx (Comprehensive Air Quality Model with Extensions) and the Direct Decoupled Method (DDM) algorithm that estimates concentration changes due to variations in emission fields. SIMBAD was validated by comparing PM10 and NO2 concentrations with CAMx simulations implementing the same emission variations. The testing scenarios involved different emission reductions and precursor species to assess SIMBAD’s performance in both simple and complex cases. The model’s performance in reproducing the non-linear nature of atmospheric processes was satisfactory, showing an average Root Mean Square Error (RMSE) always lower than 0.2 μg/m3 and a normalised bias below 2%. Slightly lower accuracy was found in more complex scenarios involving multiple pollutants and sectors modified simultaneously. Overall, SIMBAD proved to be an efficient and accurate tool for evaluating the impacts of energy policies on air quality, providing valuable insights for policymakers and researchers alike.
CFD simulation of double-pass solar dryer with air return
Authors: Droguy Y N , Koffi P E , Sissoko A , Andji J , Soro Y , Gbaha P 
Published: February 2024

Abstract
An indirect solar dryer was designed and manufactured in Yamoussoukro, Côte d’Ivoire. It is equipped with three parameters including two air intake ports, a fan and a removable hot air recovery system. Vacuum CFD simulations were performed in order to observe the influence of these parameters on the effectiveness of the device. The fan switched off speeds of 9 m/s and made the air distribution uniform in the drying cabin. The natural convection operation made it possible to reach 62°C in the drying chamber compared to 55°C for the forced convection operation. The unique opening of the low air intake port in operation accentuates the temperature variations in the cabin compartments with differences of + 5°C from one level to another. The hot air return system has a positive impact on temperature trends because it allows values of 65°C to be reached inside the chamber, ideal for drying agri-food products. However, this recovery reduces the air velocity in the cabin, which is a disadvantage for the performance during products. This problem could be solved by increasing the fan power.
Features of numerical modeling electrical coalescence in a droplet-layer system using the arbitrary Lagrangian-Eulerian method
Authors: Elagin I A , Yagodin G S , Chirkov V A 
Published: February 2024

Abstract
The electrocoalescence of a water drop at the water-oil interface was numerically analyzed using the finite element method by solving a set of equations including hydrodynamics and electrostatics. The simulation was performed using COMSOL Multiphysics software, the interface movement was implemented using an arbitrary Lagrangian-Eulerian method (also called the moving-mesh method). The influence of the initial distance from the drop to the layer, as well as the size of the entire domain on the outcome of the process was studied. The electrical coalescence and non-coalescence of a single uncharged droplet with a layer under the action of the DC field were calculated in a wide range of electric field strength. The created computer model makes it possible to calculate the voltage dependence of the detached droplet volume and charge. Also, it can help to determine features of non-coalescence, including the stretching of the droplet along the interelectrode gap and spraying.
Numerical modeling of interaction of turbulent flow with trash screen in open channels
Authors: Kokkiligadda Gangadhar , Dhar Anirban , Reddy Hanmaiahgari Prashanth 
Published: February 2024

Abstract
Trash screens are widely employed at the entrance of hydraulic structures, water intakes, and pumping stations to trap flowing debris that could exasperate downstream troubles. The characteristics of the vertical trash screen flow are measured using a Three-Dimensional Acoustic Doppler Velocimetry instrument for different flow conditions. The governing equations of the flow are numerically solved using k–ω SST, k–ϵ STD, k–ϵ RNG, and Reynolds Stress Model (RSM) and Large Eddy Simulations (LES). ANSYS-Fluent is used for these numerical simulations. The free surface of the vertical trash screen flow is computed by the volume of fluid method. The Grid Convergence Index is used to analyze the impact of the chosen grid structure on the numerical results. Experimental measurements of the velocity field and free surface profiles are compared with the numerical results of 3D simulations for validation. This study aims to identify the behavior of flow through screens in more detail through experimental and numerical simulations. The computed flow profiles considering all five cases agree well with the measured profile, whereas streamwise velocity in most portions of the flow, the k-ω SST outperforms the other models, and the RSM turbulence model is the second most effective.