Interaction Problems Research Articles

A multi-frequency interpolation method for bi-material topology optimization of vibro-acoustic problems

In practical vibro-acoustic problems, external excitation normally contains a certain frequency band structure, and system optimization needs to be performed through frequency band analysis. To reduce the high computation burden in frequency band optimization, we propose a multi-frequency interpolation method for bi-material topology optimization of the vibro-acoustic interaction system. A highly accurate solution of the vibro-acoustic interaction problem is achieved by combining the advantages of the structural finite element method and the acoustic boundary element method. A structural material interpolation model is established using the solid isotropic material with penalization method, and the topological sensitivity formulation is derived based on the adjoint variable method. On the basis of the smoothness property of the radiation impedance matrix, the matrix interpolation method is adopted to obtain the objective function at the frequency points in the frequency band of interest, thus improving the computational efficiency of frequency band topology optimization. The zero points of the Chebyshev polynomial are selected as the interpolation nodes to improve calculation accuracy. The effectiveness of the proposed multi-frequency interpolation method is verified by several numerical tests, and the radiated sound power is reduced considerably after the developed bi-material topology optimization.

Transient computational homogenization of heterogeneous poroelastic media with local resonances

AbstractA computational homogenization framework is proposed for solving transient wave propagation in the linear regime in heterogeneous poroelastic media that may exhibit local resonances due to microstructural heterogeneities. The microscale fluid‐structure interaction problem and the macroscale are coupled through an extended version of the Hill‐Mandel principle, leading to a variationally consistent averaging scheme of the microscale fields. The effective macroscopic constitutive relations are obtained by expressing the microscale problem with a reduced‐order model that contains the longwave basis and the so‐called local resonance basis, yielding the closed‐form expressions for the homogenized material properties. The resulting macroscopic model is an enriched porous continuum with internal variables that represent the microscale dynamics at the macroscale, whereby the Biot model is recovered as a special case. Numerical examples demonstrate the framework's validity in modeling wave transmission through a porous layer.

Determinants of speech and language delay among children aged 12 months to 12 years at Yekatit 12 Hospital, Addis Ababa, Ethiopia: a case–control study

BackgroundSpeech and language delay among children can result in social interaction problems, attention difficulties, decreased writing and reading abilities, and poor cognitive and behavioral development. Despite the mounting prevalence of speech and language delays in Ethiopia, there is a lack of literature addressing the factors contributing to this delay. Consequently, this study aims to identify determinants of speech and language delay among children aged 12 months to 12 years at Yekatit 12 Hospital in Addis Ababa, Ethiopia.MethodsWe conducted an institutional-based at Yekatit 12 Hospital, unmatched case–control study with 50 cases and 100 controls aged 12 months to 12 years. Interviewer-administered questionnaires were used to collect data from the parents or caregivers of the participating children. Epi Info v7 was used for sample calculation, and SPSS v26 was used for analysis. The chi-square test was performed to determine the relationship between speech and language delay and determining factors, which was then followed by logistic regression. The significant determining factors were identified based on the adjusted odds ratio (AOR), with a 95% CI and p-value (< 0.05).ResultsCase group constituted 23 males and 27 females, totaling 50 children. Upon completing the multivariate analysis, birth asphyxia [AOR = 4.58, 95CI (1.23–16.99)], bottle-feeding [AOR = 4.54, 95CI (1.29–16.04)], mother–child separation [AOR = 2.6, 95CI (1.05–6.43)], multilingual family [AOR = 2.31, 95CI (1.03–5.18)], and screen time greater than two hours [AOR = 3.06, 95CI (1.29–7.28)] were found to be statistically significant determinants of speech and language delay.ConclusionsOur study found that birth asphyxia, bottle-feeding, mother–child separation, being from a multilingual family, and excessive screen time contribute significantly to speech and language delay. As a result, it is important to develop interventions that target these modifiable factors, while also ensuring that early diagnosis and treatment options are readily accessible.

Проблемы взаимодействия преподавателя и студента в учреждении профессионального образования

Продуктивное взаимодействие между преподавателями и студентами имеет важное значение для эффективного обучения и развития студентов. Оно важно для обогащения образовательного процесса, стимулирования активного участия студентов в жизни университета и их личностного развития. Выявлено, что позитивное взаимодействие преподавателя и студентов способствует улучшению качества обучения и созданию благоприятной обучающей среды. Подчеркивается, что в ходе взаимодействия проявляется мотивация на понимание, развитие критического мышления, развитие социальных и коммуникативных навыков, укреплению самооценки и уверенности в своих собственных знаниях и умениях. В статье проведена логическая связь между понятиями «взаимодействие» и «общение». Определены функции общения: прагматическая, функция подтверждения, внутриличностная функция общения. Проведено исследование мнений студентов о типах и стилях общения преподавателей и обучающихся. Результаты показали, что имеет место существование не только доверительных и поддерживающих отношений, но и наличие коммуникативных барьеров, что является своеобразным психологическим препятствием на пути к адекватной передаче информации между партнерами по общению. Выявлены причины наличия коммуникативных барьеров: различия в коммуникативных стилях, недостаточное внимание к аспектам психологии обучения, недостаточная обратная связь, эмоциональное напряжение. Выделены пути преодоления коммуникативных барьеров: общая деятельность и согласованность действий, жизнетворчество, субъектность и диалогичность, совместная деятельность. Productive interaction between teachers and students is essential for effective learning and development of students. It is important for enriching the educational process, stimulating students' active participation in the life of the university and their personal development. It is revealed that positive interaction between teacher and students contributes to improving the quality of learning and creating a favorable learning environment. It is emphasized that during the interaction the motivation for understanding, development of critical thinking, development of social and communicative skills, strengthening of self-esteem and confidence in their own knowledge and skills are manifested. The article makes a logical connection between the concepts of "interaction" and "communication". The functions of communication are defined: pragmatic, confirmation function, intrapersonal function of communication. The study of students' opinions about the types and styles of communication between teachers and students was conducted. The results showed that there is not only the existence of trusting and supportive relationships, but also the presence of communicative barriers, which is a kind of psychological obstacle to the adequate transfer of information between communication partners. The reasons for the presence of communicative barriers are revealed: differences in communicative styles, insufficient attention to aspects of learning psychology, insufficient feedback, emotional tension. The ways of overcoming communicative barriers are identified: common activity and coordination of actions, life creativity, subjectivity and dialogicality, joint activity.

Space–time finite element method with domain reduction techniques for dynamic soil–structure interaction problems

AbstractDesign of earth structures, such as dams, tunnels, and embankments, against the vibrational loading caused by high‐speed trains, road traffic, underground explosions, and, more importantly, earthquake motion, demands solutions of the dynamic soil–structure Interaction (SSI) problem. This paper presents a velocity‐based space–time finite element procedure, v‐ST/finite element method (FEM), to solve dynamic SSI problems. The main goal of this study is to present the computation details of implementing viscous boundary conditions of Lysmer–Kuhlemeyer to truncate the unbounded soil domain. Furthermore, additional time‐dependent boundary conditions, in terms of the free‐field response, are included to facilitate energy flow from the far field to the computation domain at the vertical truncated boundaries. In the FEM, seismic input motion is applied to an effective nodal force vector, which can be obtained explicitly in the numerical simulations. Finally, the response of a concrete gravity dam resting on an elastic half‐space to the horizontal component of earthquake motion is computed and successfully compared with the results of semidiscrete FEM using the Newmark‐ method.

Experimental and numerical investigations to the aeroelastic response of flexible thin airfoil

The paper investigates the phenomenon of the aeroelastic response of flexible thin airfoils under various angles of attack (AOAs) and flow velocities through wind tunnel experiments and numerical simulations. The vibration modal characteristics are explored, including vibration frequencies, amplitudes, modal transition, and instantaneous characteristics. Vibration is directly measured using non-contact laser sensors, and the numerical model is appropriately configured to simulate the fluid–structure interaction (FSI) problem under large deformation. Experiments cover a range of AOAs (1°–20°) and incoming velocities (from 10 to 73 m/s), with dynamic responses measured using four laser sensors. Both average and instantaneous modal response features are analyzed, revealing multi-modal characteristics as velocity and AOA increase. The vibration mode transitions from pure bending to higher-order modes as incoming velocity increases. Specifically, at higher velocities and increased AOA, the high-order vibration component shifts from bending-torsional coupled mode to pure-torsional mode. Comparison of vibration frequencies between experimental measurements and finite element method simulations highlights significant shifts, particularly in the pure-torsional mode. Furthermore, employing commercial software ANSYS CFX and ANSYS Mechanical, a two-way three-dimensional FSI model successfully replicates flutter boundaries observed experimentally at 1° AOA and approximately incoming velocity 73 m/s. This FSI model is extended to simulate the multi-modal vibrations at 15° AOA, yielding insights into flow phenomena contributing to multi-modal vibration at this AOA. An explanation is provided for the multi-modal vibration phenomenon observed in the experiments based on the above insight. Finally, the differences between the experimental and numerical simulations are speculated upon.

Effects of synthetic site water on bentonite-concrete system for a potential nuclear waste repository

In high-level nuclear waste (HLW) repositories, concrete and compacted bentonite are designed to be employed as buffer materials, which may raise a problem of interactions between concrete and bentonite. These interactions would lead to mineralogy transformation and buffer performance decay of bentonite under the near field environment conditions in a repository. A small-scale experimental setup was established to simulate the concrete-bentonite-site water interaction system from a potential nuclear waste repository in China. Three types of mortars were prepared to correspond to the concrete at different degradation states. The results permit the determination of the following: (1) The macro-properties of Gaomiaozi (GMZ) bentonite (e.g. swelling pressure, permeability, the final dry density, and water content of reacted samples); (2) The composition evolution of fluids from the synthetic site water-concrete-bentonite interaction systems; (3) The sample characterization including Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). Under the infiltration of the synthesis Beishan site water (BSW), the swelling pressure of bentonite decreases slowly with time after reaching its second swelling peak. The flux decreases with time during the infiltrations, and it tends to be stable after more than 120 d. Due to the cation exchange reactions in the BSW-concrete-bentonite systems, the divalent cations (Ca and Mg) were consumed, and the monovalent cations (Na and K) were released. The dissolution of minerals in the bentonite such as albite causes Si increasing in the pore water. It was concluded that the hydro-mechanical property degradation of bentonite takes place when it comes into contact with concrete mortar, even under low-pH groundwater conditions. The soil dispersion, the uneven water content, and the uneven dry density in bentonite samples may partly contribute to the swelling decay of bentonite. Therefore, the direct contact with concrete has an obvious effect on the performance of bentonite.

Wavy approach for fluid–structure interaction with high Froude number and undamped structure

This paper addresses the fluid–structure interaction problem, with an interest on the interaction of a gravity wave with a flexible floating structure, anchored to a seabed of constant depth. To achieve this goal, we make use of the model equations, namely, the Navier–Stokes equations and the Navier–Lamé equation, as well as the associated the boundary conditions. Applying the multi-scale expansion method, these set of equations are reduced to a pair of nonlinearly coupled complex cubic Ginzburg–Landau equations (CCGLE). By applying the proposed modified expansion method, the group velocity dispersion and second-order dispersion relation are deduced. In the same vein, modulation instability (MI) is investigated as a mechanism of formation of pulse trains in fluid–structure system using a CCGLE. For the analytical analysis, we made use of the inverse scattering method to find analytical solutions to the coupled nonlinear equations. Through that method, the obtained solutions depict rogue-shaped waves. Our results suggest that uncontrolled MI within the interaction between a flexible body and gravity waves in viscous flow may be considered as the principal source of many structural ruptures, which are the first cause of critical damage due to the great energy and unpredictability of rogue waves. The present work aims to provide tools to model a wide range of physical problems regarding the interaction of surface gravity waves and an offshore-anchored structure, and it aims to be essential to our understanding of the nonlinear characteristics of offshore structures in real-sea states.

Recommendations on finite element modelling of non-seismic excitation in soil-structure interaction problems

Recommendations on finite element modelling of non-seismic excitation in soil-structure interaction problems

Exploring the Composer-Performer-Teacher Role Complex in Fostering Creativity in Music Education

The article considers the interaction system between the processes of creating a musical composition, performance and pedagogy, which is currently a particularly topical issue. The main purpose of the article is to actualise the attention to this dilemma of representatives of the Ukrainian musical and pedagogical community, including composers, performers, teachers, and to comprehend the importance of the triune role complex. The article analyses the block “composer – performer – teacher” using the methods of historical and interdisciplinary approaches. Data different in nature, directions of musical activity constitute a single whole in real practice. The system of the educational process in various educational institutions, the problems of interaction between the teacher and the student, the specifics of the self-realisation of the individual in the creative musical area were also covered. In the course of the study, it was determined that composer creativity, performance and music education are carried out in the interaction process of such objects as music and pedagogy, teacher and student, various kinds of contacts among employees on creative and educational activities in terms of world and, in particular, Ukrainian culture. The practical significance of the study is to update and expand the scope of the modern educational system through the application of the trinity principles “composer – performer – teacher” in the process of mastering the curriculum. It is designed to make the interaction of professional musicians with the audience and students more effective, to create the conditions necessary for the training of musical personnel of the highest level, and also to form an awareness of the importance and equivalence of each of the components of this triad.

Interaction problems of drugs and food in older patients. Short Review

The interaction between drugs and food in the body of older patients is an important therapeutic problem. As a result of this interaction, both the assimilation of food by the patient's body and the effectiveness and safety of drug therapy can change. Older patients may develop several complications and adverse reactions that change the underlying disease course against the background of age-related metabolic and functional disorders that change both the drugs' pharmacokinetics and pharmacodynamics and the metabolism of food substances. Considering the compatibility mechanisms of medicinal substances with certain food products, compliance with appropriate food regimes is a necessary condition for the effectiveness and drug therapy safety for older patients. __________________________________________________________________________________________ Keywords: older patients; drugs; food; therapeutic problem; pharmacokinetics; pharmacodynamics

Skip connection information enhancement network for retinal vessel segmentation.

Many major diseases of the retina often show symptoms of lesions in the fundus of the eye. The extraction of blood vessels from retinal fundus images is essential to assist doctors. Some of the existing methods do not fully extract the detailed features of retinal images or lose some information, making it difficult to accurately segment capillaries located at the edges of the images. In this paper, we propose a multi-scale retinal vessel segmentation network (SCIE_Net) based on skip connection information enhancement. Firstly, the network processes retinal images at multiple scales to achieve network capture of features at different scales. Secondly, the feature aggregation module is proposed to aggregate the rich information of the shallow network. Further, the skip connection information enhancement module is proposed to take into account the detailed features of the shallow layer and the advanced features of the deeper network to avoid the problem of incomplete information interaction between the layers of the network. Finally, SCIE_Net achieves better vessel segmentation performance and results on the publicly available retinal image standard datasets DRIVE, CHASE_DB1, and STARE.

Юридическая логика: генезис, значение и место в современной теории государства и права

This paper examines the theoretical and historical issues of the emergence, formation and development of special legal logic, and predicts possible trends in the further development of legal logic as a special theory of state and law. The question of the relationship between special legal logic and general formal logic is considered. The author's view on the periodization of the formation and historical development of legal logic as a scientific discipline about the laws of legal thinking is given. Within the framework of this work, the question of the relationship and role of metaphysical and dialectical methods in legal research, which is important for the methodology of legal science, is examined, the historical relationship of these methods is considered, an attempt is made on the basis of scientific sources on which the authors relied when preparing this study, as well as with taking into account the author’s own position developed when working on this research, forecast trends in the further development of legal logic and identify emerging trends in the development of legal methodological research. For the purpose of studying the problems of interaction between logical and legal sciences, determining the subject of legal logic by considering historical examples of attempts to “logize” state legal phenomena using universal logical constructions, the result of which, contrary to the expectations of the researchers carrying them out, was the reverse process of “legalization” of the applied universal logical constructions, their enrichment with the specifics of state-legal phenomena and institutions, justifying the independence of the subject area of legal logic, special attention in this work is paid to the study of the process of transformation of the metaphysical theory of G.V.F. Hegel into his political dialectics. For the purpose of identifying trends in the development of the methodological foundation of legal logic, this work examines the problems of the relationship between rationalistic and empirical approaches in legal research. At the conclusion of this study, the authors consider the question of the possibility of forming special theories of state and law, which was previously raised by Professor A.B. Vengerov, outlines the author's approach to this issue, and proposes an approach to the question of the place of legal logic in the system of scientific knowledge as a special theory of state and law.

Numerical Validation of Fully Coupled Nonlinear Seismic Soil–Pile–Structure Interaction

While many researchers have broadly studied soil–structure interaction (SSI) problems to comprehend SSI effects on the overall system’s behavior, some critical numerical modeling issues have not been sufficiently investigated to achieve the most accurate results. Furthermore, most scholars have not provided detailed explanations of the validation process for their proposed numerical models. Modeling pile foundations in a three-dimensional (3D) continuum system in a fully coupled manner is often challenging for engineers who do not specialize in structural and geotechnical earthquake engineering, as it can be very time-consuming and complicated. Therefore, this work aims to validate a finite element model of seismic soil–pile–structure interaction (SPSI) problems in a continuum soil body by comparing the results of numerical models with those of a centrifuge test and computed numerical simulations available in the literature. In this regard, several newly developed elements in OpenSees (Version 3.6.0) are tested. The results of this work demonstrate a closer alignment with prior experimental research findings. It is believed that providing detailed numerical modeling and validation processes will assist researchers in better understanding crucial issues in modeling soil–pile–structure interaction problems.

Нарратив как смыслообразующий элемент политической символизации

The article deals with a theoretical analysis of the concept of political narrative as a political reality, which is not reducible to a set of positivistically established facts. In the context of political symbolization, narratives as elements of interpretation of politics implicate political meanings through verbal situations that develop as an interaction of judgments. Political narratives function as mediators in social activities and not only communicate information, but do it incrementing new meanings, as political narratives are conveyed through deliberation. The “narrative identity” is formed as a reference to metanarratives and their creators. The author shows that any symbolic political reality is a constellation of involvement narratives that create verbal situations of interactions between community members and the collective history as a narration. Therefore, a narrative introduces individuals into a political context. This enables to fix the narrative “footprint” of joint social practices that are named “culture”, “nation”, “country”, etc. At the same time, the author substantiates that the form and the content of political narratives have the meaning of retrospective inner causality, since the inherited array of political interpretations is constantly «retold» in the present reality. It is concluded that in the context of political symbolization, narrative can be an analytical solution of the problem of interaction between individual consciousness and a society.

Relationship between the Significant Solutions of Static Traffic Assignment Problems for Mixed Traffic Flow of Connected and Automated Vehicles and Human-Driven Vehicles

Connected and automated vehicles can reduce the traffic congestion level of the entire network through platoon-driving technologies compared to human-driven vehicles. One promising approach to enhancing platoon-driving technology’s efficiency is deploying dedicated lanes or roads for connected and automated vehicles. Since asymmetric interactions between different vehicle types increase road congestion, it is necessary to distinguish routes for efficient traffic management. However, the traditional traffic assignment problem, which uses only user equilibrium as a constraint with no difference in travel time between users, could not be proposed as a globally optimal solution because it generates an infinite number of locally optimal solutions. Recent studies have attempted to overcome the limitations by considering the sum of system-wide travel times as an additional constraint. Their research sought to help propose optimal deployment strategies through the lowest total travel time solution (best-case) or design robust transport planning strategies through the highest total travel time solution (worst-case). However, past studies have not focused on the possibility of the best/worst case appearing in reality. This study focused on the relationship between the two solutions pointed out in past studies and traffic patterns likely to appear in reality. This study interprets the Karush–Kun–Tucker condition of the static traffic assignment problem, considering the asymmetric interaction, and proposes a solution algorithm using discrete dynamics. The proposed algorithm extends the most widely used method in transportation planning research, which can overcome the limitations of asymmetric interaction problems through simple variations. The proposed algorithm can reliably derive two solutions, and entropy theory shows that both solutions are unlikely to appear in reality without additional policies such as dedicated lanes or roads.

Implementation and Validation of an Original OpenFOAM Code for Fluid–Structure Interaction Problems in Compressible Flow

Implementation and Validation of an Original OpenFOAM Code for Fluid–Structure Interaction Problems in Compressible Flow

Theoretical and Legal Principles of Interaction between Public Authorities and the Public Under the Legal Regime of Martial Law

The concept of civil society became relevant again at the end of the twentieth century due to the development of democratization, digitalization, and globalization. Today, the issue of public participation in addressing issues of public importance is increasingly associated with electronic petitions, public consultations and discussions, public expertise, etc. The problem of interaction between public authorities and the public in the field of regional planning requires a broad interdisciplinary understanding not only at the level of infrastructure projects, but also in the field of mobilization training and mobilization, identification and solution of humanitarian problems of the population in the de-occupied territories under martial law. Along with public authorities and the public, the world of technology and artificial intelligence is gaining more and more independence, which is becoming more and more independent of the regulatory and coordinating influence of a person, organization, or state from the platform of interaction, the object of influence. At the same time, social networks are reaching an increasing number of people and are being monetized, which necessitates a more comprehensive, strategic vision of the interaction of public authorities with social networks. For the sake of better understanding of the theoretical and legal framework for interaction between public authorities and the public under martial law, an attempt was made to comprehend the problems that occurred in the field of public relations under study before the introduction of martial law in Ukraine, and which also emerged as a new challenge during the period under study, generating the relevant social transformations.

THE ETHICAL IMPORTANCE OF ARTIFICIAL INTELLIGENCE IN B2B MARKETING: A CRITICAL ANALYSIS

The article discusses some relevant philosophical and methodological aspects of the analysis of the processes of digitalization of markets and the introduction of digital technologies in business management related to digital ethics. The empirical research conducted by the author is aimed at identifying current trends in the implementation of artificial intelligence in marketing, the attitude of company management to the implementation of these processes, awareness of ethical aspects and problems of interaction with consumers. The goal of the work is to advance the issues of determining the attributes of digital ethics for the use of artificial intelligence in business: assessing the awareness of new opportunities and risks in Russian entrepreneurship. These issues naturally attract the attention of Russian. In this regard, a number of ethical problems relevant to the digital space are identified, such as problems of information wars and cyber attacks, problems of information security, privacy of private life, primacy of information sources, digital education technologies, transformation of moral values, in particular , perceptions of cruelty and violence in the digital entertainment industry, ethics of virtual communities, the use of artificial intelligence and virtual reality in production teams. The issues of developing the business environment, in particular, the reputational risks of companies in the context of the emergence of a new digital ethics, also deserve special attention . The wide public response to the ethical aspects of digitalization of various aspects of public relations has led to the development of a number of international and Russian documents that bring to the fore the observance of ethical principles and norms in the new environment of life and development of society. About two dozen large Russian companies and organizations signed the first Russian “Code of Ethics for Artificial Intelligence” at the end of 2021. The Artificial Intelligence Code states that responsibility in the application of this technology must always remain with humans. Its development is provided for by the AI Development Strategy until 2030 and the federal project “Artificial Intelligence”. For now, compliance with the norms of this document is voluntary. There are similar documents in 20 countries, 35 large companies in the world already have their own codes, in Russia - Sberbank and Yandex (Artificial Intelligence...). At the end of 2022, the European Union adopted the European Declaration on European Digital Rights and Principles (European Digital Rights.). Keywords: digital ethics, business ethics, artificial intelligence, marketing, parasocial relationships.

Stability of Beam Bridges Under Bridge-Vehicle Interaction

In this paper, we provide an accurate and reliable formulation for simulating the interactions of both train/bridge subsystems and suitable for high-speed railway lines as well as for existing lines worldwide that are being renewed or modernized. We model the train as a series of suspended masses, taking into account the energy dissipation and the suspension system for each train vehicle. On the other hand, the bridge supporting the rails with irregular elevations will be modeled as an Euler-Bernoulli beam. The mathematical formulation of the interaction problem between the two subsystems requires the writing of two sets of equations, which interact with each other through contact forces. Using a one-dimensional finite element formulation, a series of equations are constructed by Modeling the beam structure. In addition, the suspended mass equations are first discretized using Newmark's finite difference formulas, which then reduce the degrees of freedom (DOF) of the vehicle to those of the bridge element. This solves the coupling problem between the two subsystems. The derived component is known as the vehicle/bridge interaction (VBI) element. On the other hand, an iterative procedure will be used subsequently to solve the non-linearity problem of the resulting system of differential equations. MATLAB programs provide results that identify the critical parameters influencing the bridge's dynamic stability.