Invariant Parameters Research Articles

J/ψ photoproduction and polarization in e+p collisions in the improved color evaporation model

We calculate the production and polarization of direct J/ψ in the improved color evaporation model in e+p photoproduction. We present the production as functions of transverse momentum, mass of the hadronic final state, and inelasticity. We also present the polarization parameters λϑ, λφ, and λϑφ in the helicity and the Collins-Soper frames, as well as the frame-invariant polarization parameter λ˜ as a function of transverse momentum and inelasticity. We find agreement with both J/ψ unpolarized cross sections and the invariant polarization parameters as a function of pT. Published by the American Physical Society 2024

Bayesian inference of frequency-specific functional connectivity in MEG imaging using a spectral graph model

Abstract Understanding the relationship between structural connectivity (SC) and functional connectivity (FC) of the human brain is an important goal of neuroscience. Highly detailed mathematical models of neural masses exist that can simulate the interactions between functional activity and structural wiring. These models are often complex and require intensive computation. Most importantly, they do not provide a direct or intuitive interpretation of this structure–function relationship. In this study, we employ the emerging concepts of spectral graph theory to obtain this mapping in terms of graph harmonics, which are eigenvectors of the structural graph’s Laplacian matrix. In order to imbue these harmonics with biophysical underpinnings, we leverage recent advances in parsimonious spectral graph modeling (SGM) of brain activity. Here, we show that such a model can indeed be cast in terms of graph harmonics, and can provide a closed-form prediction of FC in an arbitrary frequency band. The model requires only three global, spatially invariant parameters, yet is capable of generating rich FC patterns in different frequency bands. Only a few harmonics are sufficient to reproduce realistic FC patterns. We applied the method to predict FC obtained from pairwise magnitude coherence of source-reconstructed resting-state magnetoencephalography (MEG) recordings of 36 healthy subjects. To enable efficient model inference, we adopted a deep neural network-based Bayesian procedure called simulation-based inference. Using this tool, we were able to speedily infer not only the single most likely model parameters, but also their full posterior distributions. We also implemented several other benchmark methods relating SC to FC, including graph diffusion and coupled neural mass models. The present method was shown to give the best performance overall. Notably, we discovered that a single biophysical parameterization is capable of fitting FCs from all relevant frequency bands simultaneously, an aspect that did not receive adequate attention in prior computational studies.

Vibrational Frequencies of Tetrachloroethylene using Lie Algebraic Framework

This study employs a sophisticated computational approach to predict tetrachloroethylene's higher overtone vibrational frequencies (C2Cl4) up to the fourth overtone. We utilize a Lie algebraic framework within the context of the vibrational Hamiltonian. The method involves replacing tetrachloroethylene's carbon-chlorine (C-Cl) bonds with unitary Lie algebras. The resulting Hamiltonian is written in terms of Casimir and Majorana's invariant operators and parameters. The derived Hamiltonian operator effectively characterizes the stretching vibrations inherent to the molecular structure. This approach enhances our understanding of the vibrational dynamics of tetrachloroethylene at higher overtones, offering valuable insights for applications in diverse scientific and technological fields.

Probing 4 × 4 quark mixing matrix

Without adhering to any specific model, we have presented 4 [Formula: see text] 4 quark mixing matrix as an extension of the 3 [Formula: see text] 3 Particle Data Group (PDG) parametrization of the Cabibbo–Kobayashi–Maskawa (CKM) matrix Using unitarity constraints as well as the hierarchy among the elements of the 3 [Formula: see text] 3 CKM matrix, we have found the hierarchy among the fourth row and fourth column elements of the 4 [Formula: see text] 4 quark mixing matrix. Further, for the fourth generation case, we have explicitly found the nine independent rephasing invariant parameters [Formula: see text]. Also, using phenomenological estimates of the fourth row and fourth column elements, we have numerically evaluated these nine parameters.

Positional Variations of Ukrainian Back Vowel Formants

The purpose of this paper is to study variations in the location of formants of Ukrainian back vowels caused by different phonetic features. To do so, the oscillograms and two-dimensional spectrograms of recorded sounds in speech flow were analyzed. The corresponding invariant acoustic parameters being the ratios between frequencies of the formants rising due to the tube resonance are determined. It is shown that different phonetic environments cause different formant configurations in vowels which is a case of sound assimilation. The following phonetic features were found to give rise to variations of Ukrainian back vowels: coda, distant assimilation by the next or preceding vowel, and progressive assimilation by the preceding hard or palatalized consonant. In particular, high vowels make the other vowels in the phonetic word move higher, and the front ones make the back ones move forward. Such formant shifts are more pronounced in unstressed positions and especially in a coda.

Discriminating Lithospheric and Asthenospheric Anisotropy Beneath Northern Oman: Sharp Contrast Observed at the Semail Gap Fault Zone

AbstractTo gain a deeper understanding of the extensive and varied lithospheric deformations beneath northern Oman, we examine seismic anisotropy in this region using splitting analysis of teleseismic shear wave data. Our study utilizes data from a dense network consisting of 13 permanent and 45 temporary seismic stations, which were operational for approximately 2.5 years starting from October 2013. By examining the azimuthal distribution of shear wave splitting (SWS) parameters, we were able to divide the study area into three sub‐regions. The stations located to the west of the Hawasina window exhibit relatively azimuthally invariant SWS parameters suggesting a single anisotropic layer. On the other hand, most of the stations located in the central and eastern regions display variations versus back‐azimuth, indicating the potential presence of depth‐dependent anisotropy. The General NW‐SE trend of the Fast Polarization Directions (FPDs) of the one‐layer anisotropy in the west and FPDs of the upper layers in the east is concordant with the strike of the structures resulting from the collision between the continental and oceanic plates. A clear contrast in SWS parameters is observed in the Semail Gap Fault Zone (SGFZ), suggesting that the SGFZ can be a lithospheric‐scale structure that hampers the intrusion of mafic magma from the southeast. Furthermore, the FPDs of the lower layer in the east exhibit an NE‐SW trend, which may be indicative of the large‐scale mantle flow resulting from the present‐day plate motion.

Stochastic robustness analysis of wing-aileron flutter suppression systems

In this work a stochastic robustness analysis approach is used to compare the performances of two non-linear flutter suppression systems designed for stabilization of a wing-aileron lifting structure. A reduced order modelling approach based on an alternative aeroelastic beam finite element is presented and used for the flutter suppression systems design, which are driven by a simple adaptive controller and a sliding mode controller, respectively. A heuristic algorithm is used to determine the simple adaptive controller invariant parameters at the design point while a simple parametric study is performed to tune the sliding mode controller. The performances of each closed loop system are evaluated taking into account mass, stiffnesses, and aerodynamics uncertainties of the aeroelastic plant also considering the presence of discrete gust disturbances.

The Effect Of Optimizers On The Generalizability Additive Neural Attention For Customer Support Twitter Dataset In Chatbot Application

When optimizing the performance of neural network-based chatbots, determining the optimizer is one of the most important aspects. Optimizers primarily control the adjustment of model parameters such as weight and bias to minimize a loss function during training. Adaptive optimizers such as ADAM have become a standard choice and are widely used for their invariant parameter updates' magnitudes concerning gradient scale variations, but often pose generalization problems. Alternatively, Stochastic Gradient Descent (SGD) with Momentum and the extension of ADAM, the ADAMW, offers several advantages. This study aims to compare and examine the effects of these optimizers on the chatbot CST dataset. The effectiveness of each optimizer is evaluated based on its sparse-categorical loss during training and BLEU in the inference phase, utilizing a neural generative attention-based additive scoring function. Despite memory constraints that limited ADAMW to ten epochs, this optimizer showed promising results compared to configurations using early stopping techniques. SGD provided higher BLEU scores for generalization but was very time-consuming. The results highlight the importance of finding a balance between optimization performance and computational efficiency, positioning ADAMW as a promising alternative when training efficiency and generalization are primary concerns.

Конденсаторная установка для сельской распределительной сети 0,4 кВ: особенности построения

Reactive power compensation based on a capacitor plant connected to a rural 0.4 kV distribution network, when using non-specialized contactors, is accompanied by the occurrence of large starting currents of capacitors. In addition, the installation of a conductor connection with load current transformers requires structural modification of the capacitor plant. In order to eliminate these disadvantages, it is proposed to use a capacitor bank controlled by a time relay and protected from inrush currents by three RL circuits. In this case, the “on-off” mode of the capacitor bank must be switched to by an internal signal of the capacitor bank setting the time interval “on-off”. Using a mathematical model, as well as a three-phase physical model with a power of 1.2 kV, the authors studied the behavior of transient and steady-state currents at various values of the parameters of RL circuits.The initial invariant parameters of the model were the reactive resistances of capacitors and inductors. The nominal value of the phase current of the capacitor bank was 2.14 A. The variable parameters were the values of the active resistances of the RL circuits, which took the values of 0, 10, 20, 30 and ∞. The oscillogram of stationary and transient current was studied. As a result, it was found that in order to match the capacitor bank to the criterion of using circuit breakers and contactors of the 0.4 kV network, the resistance value of the RL circuit resistor of each phase of a three-phase capacitor bank should be tenfold higher than the reactance of the current-limiting coil of the RL circuit and be five times less than the reactance value of the power capacitor of the capacitor bank phase. In rural 0.4 kV electric networks, a single 25 kV capacitor plant with simple autonomous control can be installed to compensate for reactive power. Several capacitor plants can compensate for reactive loads of 50 and 75 kVAr.

Convergence analysis of a synchronous gradient estimation scheme for time-varying parameter systems

For the problem of time-varying parameter estimation and its convergence, this paper proposes an invariant matrix to represent the changing laws of time-varying parameters, which suggests a novel expression to describe the parameters by employing finite terms. A joint recursive least squares algorithm is derived by minimizing the criterion function associated with the unknown invariant matrix. For a class of time-varying systems, a joint stochastic gradient algorithm with the computational efficiency is obtained by analogy to achieve the estimation of invariant matrix and system parameters. The convergence analysis is explored to demonstrate that the time-varying parameter estimation error is bounded under the persistent excitation conditions. The simulation results also validate the effectiveness of the proposed synchronous parameter estimation approach.

Neutrino mass model in the context of Δ(54)⊗Z2 ⊗ Z3 ⊗ Z4 flavor symmetries with Inverse Seesaw mechanism

Our analysis involves enhancing the Δ(54) flavor symmetry model with Inverse Seesaw mechanism along with two SM Higgs through the incorporation of distinct flavons. Additionally, we introduce supplementary Z2⊗Z3⊗Z4 symmetries to eliminate any undesirable components within our investigation. The exact tri-bimaximal neutrino mixing pattern undergoes a deviation as a result of the incorporation of extra flavons, leading to the emergence of a non-zero reactor angle θ13 that aligns with the latest experimental findings. It was found that for our model the atmospheric oscillation parameter occupies the lower octant for normal hierarchy case. We also examine the parameter space of the model for normal hierarchy to explore the Dirac CP (δCP), Jarlskog invariant parameter (J) and the Neutrinoless double-beta decay parameter (mββ) and found it in agreement with the neutrino latest data. Hence our model may be testable in the future neutrino experiments.

A Brief History of General‐to‐specific Modelling*

We review key stages in the development of general‐to‐specific modelling (Gets). Selecting a simplified model from a more general specification was initially implemented manually, then through computer programs to its present automated machine learning role to discover a viable empirical model. Throughout, Gets applications faced many criticisms, especially from accusations of ‘data mining’—no longer pejorative—with other criticisms based on misunderstandings of the methodology, all now rebutted. A prior theoretical formulation can be retained unaltered while searching over more variables than the available sample size from non‐stationary data to select congruent, encompassing relations with invariant parameters on valid conditioning variables.

Simple adaptive wing-aileron flutter suppression system

In this work a simple adaptive flutter suppression system is designed in order to increase the operative speed range of a wing-aileron aeroelastic plant. The equivalent beam finite element based aeroelastic modeling of a wing equipped with a trailing edge aileron in incompressible flow is presented and its state space representation is provided. The almost strictly passivity of the plant is assured by means of a parallel feed-forward compensator implementation and the invariant controller parameters are tuned using a population decline swarm optimization algorithm that minimize the integral of the time absolute error on the wing tip torsion angle. The performance of the closed loop system are studied carrying out numerical simulations that reproduce different flight scenarios with the presence of speed variations, disturbances, and gusts proving the effectiveness of the proposed simple adaptive flutter suppression architecture.

Peculiarities of the mutual influence of Italian and Chinese musical theater tradition in historical development

Statement of the problem. Despite the fact that the musical is one of the leading theatrical genres of American musical culture, no attempt has yet been made to identify its invariant parameters. The purpose of the study is to determine the main features of the genre invariant of the musical and its interpretation in the musical “Wicked” by S. Schwartz. The scientific novelty of the research lies in the fact that for the first time S. Schwartz’s musical “Wicked” is considered from the point of view of embodying the features of the genre invariant. The follows methods were used in the study: structural and functional analysis, which helps to reveal the main components that make up the musical genre; genre-stylistic analysis – aimed at identifying a genre invariant; comparative analysis to juxtapose the features of the libretto and compositional and dramaturgical principles of the musical “Wicked” with the structure of the genre invariant. Research results. Based on the overview of the researches, we consider such invariant traits of the musical genre as: 1) a two-act structure with a more detailed first act and a shorter second act, because that the second act is aimed at the resolution and contains much less new material; 2)the presence of three key dramaturgical nodes – the finale of the first act, which brings with it a plot twist (or the development of the main character line), which should bring the audience back after the intermission; 3) the thematic unity of the musical, which is provided by repetitions of large musical fragments or whole numbers, which we propose to call the reprise system; 4) thematic unity at the micro level, which is ensured by the use of cross-cutting themes and leitmotifs; 5) the leading role of the duet as the main compositional

QCD mesonic screening masses using Gribov quantization

The screening masses of mesons provide a gauge invariant and definite order parameter of chiral symmetry restoration. Different mesonic correlation lengths for flavor non-singlets, at least up to NLO, are well-defined gauge invariant physical quantities calculated earlier using the perturbative resummation techniques. The NLO perturbative results match the available non-perturbative lattice QCD results at the high-temperature regime. We have studied the spatial correlation lengths of various mesonic observables using the non-perturbative Gribov resummation, both for quenched QCD and (2+1) flavor QCD. The study follows the analogies with the NRQCD effective theory, a well-known theory for studying heavy quarkonia at zero temperature.

The Evaluation of the Relationship Between Intercondylar and Intercanine Distances, Maxillary Central Incisor Width, and Various Facial Forms: A Comparative Study.

Background The intercondylar distance is a predictable and invariable parameter, which is not influenced by the soft tissue limitations and resorption unlike comparable anatomical markers. Limited studies are available on the use of intercondylar distance for the selection of teeth arrangement and its relationship with varying face forms. Aim The study aimed to evaluate the relationship between intercondylar distance and maxillary intercanine tip distances and central incisor width in square, tapering, and ovoid facial forms. Materials and methods The comparative cross-sectional study was performed between January 2021 and August 2022. A convenience sampling strategy was used to include subjects between the ages of 18 and 40 years who had all of their natural teeth.The facial forms of the subjects were detected using a face form indicator and grouped into ovoid (group A), tapering (group B), and square (group C) forms comprising 63 subjects in each group. The intercondylar and intercanine distances and maxillary central incisor width were measured using a digital caliper. The Statistical Package for Social Sciences (SPSS) software (IBM SPSS Statistics, Armonk, NY) was employed to determine the statistical difference between and across the groups using one-way analysis of variance (ANOVA) and post hoc analysis, respectively. The correlation between the variables was determined by the Pearson correlation test. Results The average age of the subjects was 24.55±3.47 years, and the age distribution was found to be statistically insignificant between the groups (p=0.63). The study consisted of 21% of males and 79% of females. The mean intercondylar distance was 125.2 mm in ovoid, 123.1 mm in tapering, and 125.9 mm in square face forms (p<0.01). The mean intercanine distance was 34.82 mm for ovoid, 37.11 mm for tapering, and 37.04 mm for square facial forms (p<0.01). Similarly, the mean central incisor width was 9, 7.84, and 8.51 mm for ovoid, tapering, and square facial forms, respectively (p<0.01). The ratio of intercondylar and intercanine distances in ovoid, tapering, and square faces was 1:3.59, 1:3.31, and 1:3.39, respectively. The ratio of intercondylar and central incisor width was 1:13.9, 1:15.7, and 1:14.7for the groups A, B, and C, respectively. There was a statistically significant negative correlation between square and ovoid incisor width, square intercanineand ovoid incisor width, tapering incisor width and intercondylar distance, tapering intercanine and intercondylar distances, and tapering incisor width and square intercanine distance. The relationship between intercondylar and intercanine distances and the central incisor width was also revealed to be statistically highly significant (p<0.01). Conclusion When face form is taken into account, tapering face form shows more positive result for the relationship of intercondylar distance with intercanine distance and central incisor width. In patients with edentulous conditions, the intercondylar distance may offer useful measurements for tooth selection.

Modeling of spatial spread of COVID-19 pandemic waves in Russia using a kinetic-advection model

Objectives. COVID-19 has a number of specific characteristics that distinguish it from past pandemics. In addition to the high infection rate, the high spread rate is due to the increased mobility of contemporary populations. The aim of the present work is to construct a mathematical model for the spread of the pandemic and identify patterns under the assumption that Moscow comprises the main source of viral infection in Russia. For this purpose, a twoparameter kinetic model describing the spatial spread of the epidemic is developed. The parameters are determined using theoretical constructions alongside statistical vehicle movement and population density data from various countries, additionally taking into account the development of the first wave on the examples of Russia, Italy and Chile with verification of values obtained from subsequent epidemic waves. This paper studies the development of epidemic events in Russia, starting from the third and including the most recent fifth and sixth waves. Our twoparameter model is based on a kinetic equation. The investigated possibility of predicting the spatial spread of the virus according to the time lag of reaching the peak of infections in Russia as a whole as compared to Moscow is connected with geographical features: in Russia, as in some other countries, the main source of infection can be identified. Moscow represents such a source in Russia due to serving as the largest transport hub in the country.Methods. Mathematical modeling and data analysis methods are used.Results. A predicted time lag between peaks of daily infections in Russia and Moscow is confirmed. Identified invariant parameters for COVID-19 epidemic waves can be used to predict the spread of the disease. The checks were carried out for the wave sequence for which predictions were made about the development of infection for Russia and when the recession following peak would occur. These forecasts for all waves were confirmed from the third to the last sixth waves to confirm the found pattern, which can be important for predicting future events.Conclusions. The confirmed forecasts for the timing and rate of the recession can be used to make good predictions about the fifth and sixth waves of infection of the Omicron variant of the COVID-19 virus. Earlier predictions were confirmed by the statistical data.

Application of acoustic emission criteria for the study of deformation processes and destruction of reinforced concrete structures

Introduction. The main results of the application of the method of acoustic emission criteria for the diagnosis of the pre-destructive state of reinforced concrete structures are presented. The paper considers the relationship between the origin and growth of microcracks in reinforced concrete beams with deviations of invariant ratios from stable values of acoustic emission parameters.The aim of the research is evaluate the possibility of using the invariant method for the diagnosis of reinforced concrete structures. Refinement of numerical values of time and amplitude invariants, time and amplitude information parameters for reinforced concrete beams. Determination of the relationship of invariants with the scale of destruction in reinforced concrete structures.Materials and methods. Experimental studies were carried out on reinforced concrete beams made of heavy concrete (compressive strength class B60, B90) and fiber concrete (compressive strength class B30, B60). In the process of testing the beams, acoustic emission measurements were carried out, the crack sizes were fixed.Results. The test results allowed us to establish numerical values of time and amplitude invariant criteria, time and amplitude information parameters for reinforced concrete beams. The numerical values of the time invariant have values close to 1, the amplitude invariant has a value of 0,1, and the information parameter of the time intervals and the amplitude information parameter are equal to 0 at the initial stage of loading the samples.Conclusions. Studies have shown the possibility of quantifying the size of cracks (the total length in the control zone) of the structure using the invariant method. The most informative are the time and amplitude invariant criteria.

An innovative approach considering active power and harmonics for modeling the electric arc furnace along with analyzing time-varying coefficients based on ARMA models

Electric arc furnace (EAF) is more and more applied in large industrial systems and represent one of the major sources of perturbations for the power system because it is highly non-linear and time-varying. New models are suggested in this research based on instantaneous EAF voltage and current measurements taken from EAFs at the Mobarakeh steel mill in Isfahan, Iran. This paper aims to develop two improved types of accurate models based on the Schavemaker model. The original Schavemaker model has three constant parameters. Unlike the original Schavemaker model which uses invariant parameters, the time-varying nature of the arc's parameters is considered in the proposed models. The first improved model has time-varying parameters. Additionally, to further enhance the model's accuracy, in the second improved model, a term has been added to the schavemaker model that includes time-varying parameters. Compared to the original Schavemaker model, all of the developed Schavemaker models are more precise. Finally, auto-regressive moving average (ARMA) models are used to attain the time variation characteristic of the parameters.

An Evolving Spacetime Metric Induced by a ‘Static’ Source

In a series of recent papers we developed a formulation of general relativity in which spacetime and the dynamics of matter evolve with a Poincaré invariant parameter τ. In this paper, we apply the formalism to derive the metric induced by a ‘static’ event evolving uniformly along its t-axis at the spatial origin x=0. The metric is shown to vary with t and τ, as well as spatial distance r, taking its maximum value for a test particle at the retarded time τ=t−r/c. In the resulting picture, an event localized in space and time produces a metric field similarly localized, where both evolve in τ. We first derive this metric as a solution to the wave equation in linearized field theory, and discuss its limitations by studying the geodesic motion it produces for an evolving event. By then examining this solution in the 4+1 formalism, which poses an initial value problem for the metric under τ-evolution, we clarify these limitations and indicate how they may be overcome in a solution to the full nonlinear field equations.