Potential Problems Research Articles

Effects of steady flow and side hull layouts on motions and added resistance of a trimaran sailing in waves

As a high-performance ship, the trimaran holds significant potential in military and civilian fields. This study proposes a novel numerical method based on the Rankine panel method for predicting the time domain motion and wave loads of trimarans navigating in waves. This approach incorporates a more accurate steady flow model for trimarans and meticulously derives the boundary value problem for the unsteady disturbance potential, while retaining the steady terms related to steady flow throughout the process. This approach ensures a comprehensive consideration of the impacts of speed effect and ship wave. The method was innovatively validated using the trimaran hull form, and its accuracy and reliability were confirmed through comparisons with experimental data. Then, the influence of steady flow on time domain motions and added resistance of trimarans was thoroughly investigated. Comparative analysis of different steady flow models demonstrates that the steady flow model for trimaran proposed provides high precision and advantages in predicting the time domain motions of high-speed trimarans in waves. Furthermore, a systematic investigation into the effects of ship speed and side hull layouts on trimaran's motion and added resistance in waves has been conducted, offering crucial technical support for trimarans' seakeeping optimal solution selection.

Multilevel interpolations for the generalized Nikishin system on a tree graph

We study a multilevel interpolation problem for a system of Markov functions defined by a tree graph. The normality of all indices has been proven. Asymptotic properties are studied in terms of the vector equilibrium problem for logarithmic potential.

Проблема интеллектуального потенциала педагога

<p><em>The article discusses the problem and place of intellectual abilities in the psychological pedagogical activity of a teacher. Attention is focused on the absence of the category “intellectual abilities” within the framework of traditional classifications of pedagogical abilities developed in Soviet and Russian educational psychology (N.V. Kuzmina, V.A. Krutetsky, A.K. Markova, etc.). The exception is the studies of L.M. Mitina, in which intelligence is obtained in the accumulation of cognitive and personal characteristics of the teacher’s activities. In view of this, this integration includes concepts and theories of psychology, abilities and intelligence for the role of understanding and intellectual abilities in the stage-by-stage psychological activity of the teacher. The possibilities of V.D. Shadrikov theory of abilities are described to understand the essence of a teacher’s intellectual abilities. The key advantage of this theory for solving the problems of teaching abilities and pedagogical intelligence is the understanding of intelligence as a systemic manifestation of human cognitive abilities.</em></p>

Nonautonomous Volterra Series Expansion of the Variable Phase Approximation and its Application to the Nucleon-Nucleon Inverse Scattering Problem

Abstract In this paper, the nonlinear Volterra series expansion is extended and used to describe certain types of nonautonomous differential equations related to the inverse scattering problem in nuclear physics. The nonautonomous Volterra series expansion lets us determine a dynamic, polynomial approximation of the variable phase approximation (VPA), which is used to determine the phase shifts from nuclear potentials through first-order nonlinear differential equations. By using the first-order Volterra expansion, a robust approximation is formulated to the inverse scattering problem for weak potentials and/or high energies. The method is then extended with the help of radial basis function neural networks by applying a nonlinear transformation on the measured phase shifts to be able to model the scattering system with a linear approximation given by the first-order Volterra expansion. The method is applied to describe the ${}^1S_0$ NN potentials in neutron+proton scattering below 200 MeV laboratory kinetic energies, giving physically sensible potentials and below $1\%$ averaged relative error between the recalculated and the measured phase shifts.

Prospects of Interdisciplinary Research into the Problem of Resource Mobilization of Academic Staff

Introduction. Mobilization of the resource potential of academic staff is a key task of university management. The development of management approaches to its solution should be preceded by a comprehensive study of both the academic staff resources and management practices. The possibilities of research are provided by an interdisciplinary theoretical and methodological framework. The purpose of the article is to substantiate the possibilities of developing interdisciplinary foundations for the study of the mobilization of the academic staff resource potential and the prospects for empirical study. Materials and Methods. The theoretico-methodological nature of the article required the use of methods for generalizing and systematizing the provisions of interdisciplinary and disciplinary approaches and theories that have been developed by social and humanitarian science. The main directions for the exploration of the problem of academic staff resource potential in modern socio-humanitarian knowledge have been identified through the method of systematic analysis of literature. Results. The main result of the research is the substantiation of the theoretical and methodological framework for an interdisciplinary study of the mobilization of the academic staff resources. This justification is based on the “revision” of theoretical and methodological provisions of theories of education. The basic interdisciplinary theories are the theories of adult continuing education, professional development and education, non-cognitive human capital, social networks, scientific and educational knowledge. Community-based, resource-based, institutional, normative, and communicative approaches are in demand. The provisions of these theories and approaches are adapted to the subject of the study. An important result of the research is the substantiation of the interdisciplinary synthesis in the practices of university management. Discussion and Conclusion. The prospects for using the interdisciplinary framework in an empirical study dealing with evaluation and activation of academic staff resources are shown. The practical significance of the results lies in the development of a model of mobilization management of the academic staff resources.

Changes in the resource potential of older generations of Russians (based on materials from longitudinal studies)

The increase in life expectancy is a global trend in the field of population. The purpose of the article is to identify the changes in the components of the resource potential of Russians belonging to different real generations but being in the same age phase of 50–69 years. The first cohort reached the age of 50–69 years in 1993, the second in 2021. Within the framework of the study, resource potential is understood as a set of significant socio-psychological, economic and personal characteristics necessary for leading an active social and everyday life. E. Rosset’s position on the lengthening of the period of adulthood with an increase in life expectancy is taken as the methodological basis of the study. The provisions of the theory of social activity and the sociological approach to personal self-sufficiency are used to identify qualitative changes in the social and personal characteristics of Russians who are at a transitional stage of their life path from maturity to old age. The research hypothesis about gradual changes in the ways of organizing life, attitudes and behavior in people in transition from adulthood to old age is tested based on a comparison of data from two studies – RUSSET, Wave 1, 1993; the National Survey of the Older Generation under the SHARE program (population 50+), 2021. The social characteristics and attitudes of respondents who are in the same age phase (50–69 years old), but belong to different age cohorts that differ by generation length, are compared. The intensity and severity of family, professional, communication, etc. differentiates life choices on a scale from “active life” to “survival”. The main result of the study was the differentiation of the components of the resource potential of the older generation into changeable and stable ones. Trends were identified that reflect qualitative changes in the resource potential of older generations of Russians. They cannot be unambiguously characterized as positive or negative. In the context of the problem of human potential, the most significant change is associated with an increase in the level of education of older Russians. Older Russians are a highly educated population with high demands on society and an active social position. The rigidity of attitudes towards retirement age and professional employment constrains the resource potential of older Russians. In conclusion, it is concluded that the results obtained during the study can serve as an additional basis for the practical implementation of tasks related to the mobilization of the human resource of older Russians.

Understanding Compartmentation Failure for High-Rise Timber Buildings

The traditional concept of compartmentation guaranteed by fire resistance is mainly concerned with the problem of destructive internal spread potential. External convective spread potential pertains to the loss of compartmentation associated with windows and facade systems. As such, it is assumed that internal fire spread occurs following mechanisms of excessive heat conduction and/or successive failure of the compartment boundaries, which can be, in most cases, conservatively characterised using traditional methods of performance assessment such as fire resistance. Nevertheless, external fire spread represents a potentially more effective route by which fire can spread through the convective advancement of flames and hot gases. This is particularly important in cases such as timber construction, where the presence of exposed timber can result in increased convective spread potential and where loss of compartmentation can result in disproportionate consequences. A simplified compartment fire model is proposed with the objective of quantifying the fuel contribution of exposed timber elements to the compartment fire and determining the impact of variable percentages of exposed timber on the convective spread potential. The overall results show that the convective fire spread potential increases with the increasing percentage of available timber.

Inverse problem in energy-dependent potentials using semiclassical methods

Wave equations with energy-dependent potentials appear in many areas of physics, ranging from nuclear physics to black hole perturbation theory. In this work, we use the semiclassical Wentzel-Kramers-Brillouin (WKB) method to first revisit the computation of bound states of potential wells and reflection/transmission coefficients in terms of the Bohr-Sommerfeld rule and the Gamow formula. We then discuss the inverse problem, in which the latter observables are used as a starting point to reconstruct the properties of the potentials. By extending known inversion techniques to energy-dependent potentials, we demonstrate that so-called width-equivalent or WKB-equivalent potentials are not isospectral anymore. Instead, we explicitly demonstrate that constructing quasi-isospectral potentials with the inverse techniques is still possible. Those reconstructed, energy-independent potentials share key properties with the width-equivalent potentials. We report that including energy-dependent terms allows for a rich phenomenology, particularly for the energy-independent equivalent potentials. Published by the American Physical Society 2024

Revisiting O(N) σ model at unphysical pion masses and high temperatures

Roy-equation analysis on lattice data of ππ scattering phase shifts at mπ=391 MeV reveals that the lowest f0 meson becomes a bound state under this condition. In addition, there is a pair of complex poles below threshold generated by crossing symmetry [X.-H. Cao , ]. We use the N/D method to partially recover crossing symmetry of the O(N) σ model amplitude at leading order of 1/N expansion, and qualitatively reproduce the pole structure and pole trajectories with varying pion masses as revealed by Roy-equation analyses. The σ pole trajectory with varying temperature is also discussed and found to be similar to its properties when varying mπ. As the temperature increases, the complex σ poles firstly move from the second Riemann sheet to the real axis becoming two virtual state poles, and then one virtual state pole moves to the first sheet turning into a bound state pole and finally tends to the pion pole position at high temperature which is as expected from the chiral symmetry restoration. Our results provide further evidence that the lowest f0 state extracted from experiments and lattice data plays the role of the σ meson in the spontaneous breaking of chiral symmetry. Finally, we also briefly discuss the problems of the effective potential in the situation when mπ and the temperature become large. Published by the American Physical Society 2024

Determination of the Energy Eigenvalues of the Varshni-Hellmann Potential

In this paper, we solve the bound state problem for the Varshni-Hellmann potential via a useful technique. In our technique, we obtain the bound state solution of the Schrödinger equation for the Varshni-Hellmann potential via ansatz method. We obtain the energy eigenvalues and the corresponding eigenfunctions. Also, the behavior of the energy spectra for both the ground and the excited state of the two body systems is illustrated graphically. The similarity of our results to the accurate numerical values is indicative of the efficiency of our technique.

Accounting and silence: The unspeakable, the unsaid, and the inaudible

AbstractThis paper studies accounting and silence. Building on studies of accounting talk and introducing theories of “silencing,” we highlight the role of accounting silences in the production of engaging organizational conversations. Through a qualitative case study, we identify three forms of silence—the unspeakable, the unsaid, and the inaudible—and their links to accounting. Silences create motivations to engage in further accounting talk, but they also deny certain groups a voice in those conversations. An impression of participation, openness, and transparency emerges despite unequal access and the silencing of certain groups. Accounting itself can be silenced to avoid uncomfortable topics, potential problems, and anxiety‐inducing uncertainties. This silencing may serve to preserve a useful ignorance, avoid being in the know, and build alluring narratives and engaging conversations. Accounting silences sustain such conversations by protecting them from alternative voices, unsettling knowledge, and narratives that are incompatible with the organization's preferred story.

Binary Graph Convolutional Network With Capacity Exploration.

The current success of Graph Neural Networks (GNNs) usually relies on loading the entire attributed graph for processing, which may not be satisfied with limited memory resources, especially when the attributed graph is large. This paper pioneers to propose a Binary Graph Convolutional Network (Bi-GCN), which binarizes both the network parameters and input node attributes and exploits binary operations instead of floating-point matrix multiplications for network compression and acceleration. Meanwhile, we also propose a new gradient approximation based back-propagation method to properly train our Bi-GCN. According to the theoretical analysis, our Bi-GCN can reduce the memory consumption by an average of ∼31x for both the network parameters and input data, and accelerate the inference speed by an average of ∼51x, on three citation networks, i.e., Cora, PubMed, and CiteSeer. Besides, we introduce a general approach to generalize our binarization method to other variants of GNNs, and achieve similar efficiencies. Although the proposed Bi-GCN and Bi-GNNs are simple yet efficient, these compressed networks may also possess a potential capacity problem, i.e., they may not have enough storage capacity to learn adequate representations for specific tasks. To tackle this capacity problem, an Entropy Cover Hypothesis is proposed to predict the lower bound of the width of Bi-GNN hidden layers. Extensive experiments have demonstrated that our Bi-GCN and Bi-GNNs can give comparable performances to the corresponding full-precision baselines on seven node classification datasets and verified the effectiveness of our Entropy Cover Hypothesis for solving the capacity problem.

Consistency, precision, and accuracy assessment of the collocation boundary element method for two-dimensional problems of potential and elasticity

Consistency, precision, and accuracy assessment of the collocation boundary element method for two-dimensional problems of potential and elasticity

Approaching certain central-field Schrödinger problems through the harmonic oscillator green's function

We propose a method to analytically solve the Schrödinger equation with central potentials. By means of Sturm–Liouville expansion, the Green's function (GF) of the Schrödinger differential operator can be represented in the GF of the isotropic harmonic oscillator. Applying this straightforward approach, we solve the Schrödinger problem for the Coulomb potential, for the Morse potential, and for the respective inverted potentials. Using the obtained results, we formulate a method to analytically solve Schrodinger equations for multi-well potentials, demonstrating that classically forbidden regions can be treated as inverted harmonic oscillators, whereas harmonic oscillators or Morse potentials can approximate the wells.

A Numerical Study of Quantum Entropy and Information in the Wigner-Fokker-Planck Equation for Open Quantum Systems.

Kinetic theory provides modeling of open quantum systems subject to Markovian noise via the Wigner-Fokker-Planck equation, which is an alternate of the Lindblad master equation setting, having the advantage of great physical intuition as it is the quantum equivalent of the classical phase space description. We perform a numerical inspection of the Wehrl entropy for the benchmark problem of a harmonic potential, since the existence of a steady state and its analytical formula have been proven theoretically in this case. When there is friction in the noise terms, no theoretical results on the monotonicity of absolute entropy are available. We provide numerical results of the time evolution of the entropy in the case with friction using a stochastic (Euler-Maruyama-based Monte Carlo) numerical solver. For all the chosen initial conditions studied (all of them Gaussian states), up to the inherent numerical error of the method, one cannot disregard the possibility of monotonic behavior even in the case under study, where the noise includes friction terms.

Measuring health-related quality of life in children with suspected genetic conditions: validation of the PedsQL proxy-report versions.

Measuring health-related quality of life (HRQoL) of children with suspected genetic conditions is important for understanding the effect of interventions such as genomic sequencing (GS). The Pediatric Quality of Life Inventory (PedsQL) is a widely used generic measure of HRQoL in pediatric patients, but its psychometric properties have not yet been evaluated in children undergoing diagnostic GS. In this cross-sectional study, we surveyed caregivers at the time of their child's enrollment into GS research studies as part of the Clinical Sequencing Evidence Generating Research (CSER)consortium. To evaluate structural validity of the PedsQL 4.0 Generic Core Scales and PedsQL Infant Scales parent proxy-report versions, we performed a confirmatory factor analysis of the hypothesized factor structure. To evaluate convergent validity, we examined correlations between caregivers' reports of their child's health, assessed using the EQ VAS, and PedsQL scores by child age. We conducted linear regression analyses to examine whether age moderated the association between caregiver-reported child health and PedsQL scores. We assessed reliability using Cronbach's alpha. We analyzed data for 766 patients across all PedsQL age group versions (1-12months through 13-18years). Model fit failed to meet criteria for good fit, even after modification. Neither age group (categorical) nor age (continuous) significantly moderated associations between PedsQL scores and caregiver-reported child health. Cronbach's alphas indicated satisfactory internal consistency for most PedsQL scales. The PedsQL Generic Core Scales and Infant Scales may be appropriate to measure HRQoL in pediatric patients with suspected genetic conditions across a wide age range. While we found evidence of acceptable internal consistency and preliminary convergent validity in this sample, there were some potential problems with structural validity and reliability that require further attention.

A dual-reciprocity boundary element method based transient seepage model with nonlinear distributed point source dual-porosity gas reservoir

As a result of advancements in gas reservoir development technologies and a deeper understanding of seepage theory, numerous nonlinear seepage problems have emerged. Consequently, conventional analytical solution models are no longer applicable. Moreover, existing semi-analytical and numerical solution models suffer from issues like high computational complexity and limited flexibility, significantly constraining their practical utility. For this purpose, a gas reservoir transient seepage model is established based on the dual-reciprocity boundary element method (DRBEM). This model couples the wellbore storage coefficients with skin factor and introduces a novel dual-porosity transient interporosity seepage algorithm, enabling the resolution of transient seepage problems in dual-porosity gas reservoirs with nonlinear point source distributions. Additionally, it investigates the dynamic behavior of bottomhole pressure during the early production stage of gas wells, while capturing the dynamic pressure distribution within the seepage field. This approach offers the advantages of semi-analyticity, meshless, and eliminates the need for Laplace transforms, resulting in a significant reduction in computational complexity. Ultimately, the application of our model to well-pattern production with the production system transition issues, in conjunction with the log-log type curves of bottomhole pressure, and the dynamics of gas reservoir pressure, enables the analysis of interference characteristics between injection-production wells. This showcases the practical advantages of the model's application. The findings of this study provide valuable assistance for modeling and solving transient seepage problems in dual-porosity oil and gas reservoirs production. The application of DRBEM in unsteady-state diffusion, heat conduction, stress fields, and other potential field problems is relevant for reference.

Optimal inverse problems of potentials for two given eigenvalues of Sturm–Liouville problems

The present paper is concerned with the infimum of the norm of potentials for Sturm–Liouville eigenvalue problems with Dirichlet boundary condition such that the first two eigenvalues are known. The explicit quantity of the infimum is given by the two eigenvalues.

Three-Dimension Calculation for the Scattering Problem for Non-Spherical Potential

The interaction of the 238U with a neutron is studied. Correct accounting for the non-spherical shape of the uranium nucleus is in focus. The optical potential is used as a model. It is shown that the spherically symmetric and non-spherical potentials give different scattering patterns, in particular different resonance features of the cross-section. The possibility of using the method as an extension of the particle–rotor model of the nucleus is illustrated.

Inverse Resonance Problems for Energy-Dependent Potentials on the Half-Line

Inverse Resonance Problems for Energy-Dependent Potentials on the Half-Line