Interaction Problems Research Articles

DEVELOPMENT OF A WEB APPLICATION FOR INTELLIGENT ANALYSIS OF CUSTOMER REVIEWS USING A MODIFIED SEQ2SEQ MODEL WITH AN ATTENTION MECHANISM

Machine learning, and neural networks in particular, are having a huge impact on business and marketing by providing convenient tools for analytics and customer feedback. The article proposes an intelligent analysis of customer feedback based on the use of a modified seq2seq deep learning model. Since the basic seq2seq model has a significant disadvantage - the inability to concentrate on the main parts of the input sequence, the results of machine learning may give an inadequate assessment of customer feedback. This disadvantage is eliminated by means of a model proposed in the work called the “attention mechanism”. The model formed the basis for the development of a web application that solves the problem of flexible interaction with customers by parsing new reviews, analyzing them and generating a response to a review using a neural network.

Current issues of intercultural interaction: experience of western countries

The current difficulties of intercultural interaction, experience of counteracting xenophobia and other problems are considered in the framework of the article on the example of Western countries, mainly the United States, as a state with a significant proportion of its population, including in percentage ratio, occupied by representatives of different races and cultures. In the course of the research the relevance and acuteness of the problems of intercultural interaction are assessed, the problems of weakening of peoples' self-awareness and formation of complexes of the race accused of xenophobia, as well as attempts to introduce xenophobic ideas into science are considered. The author also touches upon the topic of selective tolerance. The research is based on the analysis of scientific and informational publications on the topic under study, both domestic and foreign, representing an inside view of the problem. The material considered in the article allows us to conclude that the problems of intercultural relations in the United States are becoming more and more complicated over time, and similar processes are taking place in other Western countries, which gives grounds to recognize the policy of fighting xenophobia as ineffective. These articles can be used as a basis for further research into the problems of intercultural interaction and the possible development of measures for the settlement and subsequent prevention of these problems.

Экспериментальные исследования динамической работы железнодорожных мостов при воздействии высокоскоростного подвижного состава

The issue of considering the dynamic interaction of the railway rolling stock and the structures of bridge structures is especially important when solving the tasks of increasing the speeds of trains on the existing railway lines, as well as when prescribing high-speed mode on designed bridges. Rational accounting of the parameters of dynamic interaction allows you to perform complete and reliable calculations of elements of bridge structures, which in turn has a beneficial effect on predicting the period and nature of the operation of structures and, because of the economic component of projects. The modern solution to the problem of dynamic interaction is reduced to determining the degree of influence of each component of the unified mechanical system of the bridge-travel. Objective: the purpose of this study is to determine the parameters of dynamic interaction through experimental measurements of stresses, accelerations, and displacements of structures of the bridge structure located on the existing railway line with an organized high-speed traffic movement. Methods: experimental measurement using high-frequency voltage sensors, accelerations and movements with subsequent statistical processing and analysis of the results. Results: graphs and tables displaying a change in the measured values of relative deformations, accelerations, and movements over time. Practical importance: The practical significance of this study is to assess the degree of influence of the components of the dynamic interaction of high-speed rolling composition and the bridge structure, which allows you to form a holistic picture of the nature of the process of dynamic interaction.

An efficient partitioned framework to couple Arbitrary Lagrangian-Eulerian and meshless vector form intrinsic finite element methods for fluid-structure interaction problems with deformable structures

The Vector Form Intrinsic Finite Element (VFIFE) is an advanced meshless Lagrangian structural solver. This study introduces a partitioned framework to integrate Arbitrary Lagrangian-Eulerian and VFIFE methods into fluid-structure interaction (FSI) problems featured by large structural displacements and deformations. The VFIFE method enables the FSI simulations with deformable structures due to the nature of Lagrangian particles, which is challenging for traditional computational fluid mechanics techniques. In addition, the VFIFE can be effectively equipped with the partitioned coupling schemes because of the versatility of governing equations. In this algorithm system, several matrix problems in finite element methods and mapping and interpolation in the fluid-structure interface can be avoided. The significant potential of this algorithm in tackling complex FSI problems is demonstrated through various benchmarks, encompassing scenarios like Taylor-Green vortex, flow over a rigid cylinder (Re = 40 ∼ 200), forced vibration of a rigid cylinder, vortex-induced vibration (VIV) of an elastically mounted cylinder, and VIV of a rigid cylinder with an attached flexible cantilever beam. Finally, an experiment on flow past a curtain in a water tank is conducted to further evaluate the precision and stability of the current coupling strategy in three dimensions, demonstrating the feasibility of such methods in flexible structures.

Модели организации деятельности полиции зарубежных государств в сфере взаимодействия с гражданским обществом

Introduction. In solving the problem of interaction between the police and civil society institutions in implementing the law enforcement function of the state, the policing experience of foreign countries can be actual for developing new conceptual provisions and dogmatic solutions adequate to contemporary conditions. The research of different models of police activity organisation in foreign countries will reveal common patterns and suggest more efficient and effective measures to organise interaction between the police and civil society institutions in Russia. Purpose of the research is to identify the most effective management mechanisms for the formation of interaction between the police and civil society institutions in implementing the law enforcement function of the state on the basis of theoretical and legal analysis of models of the organisation of police activities in foreign countries. Theoretical aspects of the organisation of local self-government, traditionally historically linked to policing, are reflected in the theses of E. S. Gorbatyuk, I. A. Gorsheneva, D. O. Ezevsky, A. M. Kononov and others. Comparative analysis of police activity of foreign states, including cooperation with civil society institutions, was carried out in the researches of I. A. Andreeva, A. V. Bykov , D. V. Vasiliev , A. V. Gubanov, E. V. Kirichok, A. K. Kiselev, O. B. Moroz, V. F. Saetgarayev, A. I. Stepanyan and others. The issues of interaction of the police and society were considered in the works of P. N. Kobets, N. S. Nizhnik, G. R. Rustemova, I. S. Prikhodko and others. The theory of the relationship between local political culture and the organisation of police activities (J. K. Wilson) was used to identify and evaluate the mechanisms of partnership between the police and society. Methods. The research is based on the system approach, general scientific methods (primarily analysis and synthesis), the method of materialistic dialectics; special methods: comparative-historical, formal-legal; historical-legal analysis, chronological method. Results. The studied models of police organisation in foreign countries are derived from the generic concept of “service model of police organisation”, are aimed at social cohesion, stability with a high level of citizen participation and are relevant for different countries. The priority task of the Russian Ministry of Internal Affairs is the social orientation of its activities, which allows police units to make their best in using the social and public potential of the Russian society in solving the tasks assigned to them.

HP3D-V2V: High-Precision 3D Object Detection Vehicle-to-Vehicle Cooperative Perception Algorithm.

Cooperative perception in the field of connected autonomous vehicles (CAVs) aims to overcome the inherent limitations of single-vehicle perception systems, including long-range occlusion, low resolution, and susceptibility to weather interference. In this regard, we propose a high-precision 3D object detection V2V cooperative perception algorithm. The algorithm utilizes a voxel grid-based statistical filter to effectively denoise point cloud data to obtain clean and reliable data. In addition, we design a feature extraction network based on the fusion of voxels and PointPillars and encode it to generate BEV features, which solves the spatial feature interaction problem lacking in the PointPillars approach and enhances the semantic information of the extracted features. A maximum pooling technique is used to reduce the dimensionality and generate pseudoimages, thereby skipping complex 3D convolutional computation. To facilitate effective feature fusion, we design a feature level-based crossvehicle feature fusion module. Experimental validation is conducted using the OPV2V dataset to assess vehicle coperception performance and compare it with existing mainstream coperception algorithms. Ablation experiments are also carried out to confirm the contributions of this approach. Experimental results show that our architecture achieves lightweighting with a higher average precision (AP) than other existing models.

Using Digital Financial Assets as Investments: Problems of the Legal Regulation

Introduction: the paper examines the problems with the legal regulation of using digital financial assets as investments. The emerging problems, according to the authors, are primarily related to the legal means inherent in the mechanism of the legal regulation of emerging legal relations, as well as to the significant specifics of relations arising on the Internet and other information and communication networks. Purpose: the purpose of the work was to identify the specific features of this relationship concerning the impossibility of geographically determining the residence of the party to the relationship and, as a result, determining the national law to be applied in relation to investing digital financial assets. Methods: the specifics of legal relations arising in the information and communication network between investors in digital financial assets and other entities have led to the use of special research methods. Among the general scientific tools, along with analysis, synthesis, deduction, and induction, the empirical method of legal modeling was used. Specific scientific methods were also used: dogmatic (formal-logical) and formal-legal, as well as the methods of legal forecasting, legal analogy, and technical-legal. Results: the paper substantiates the complex composition of legal relations, the parties to which are both “legal” and “technical” entities. The interrelationship between the actions of the parties causing legal consequences is shown. It is proposed to classify the parties to legal relations arising in the virtual network in the process of investing digital financial assets into the main ones, whose actions generate legal consequences, and the auxiliary (additional) ones, whose actions provide the possibility of legal consequences. It is argued that the process of emerging legal relations is influenced by the actions of all parties, both basic and auxiliary. An important problem of interaction in the virtual network in the process of investing digital financial assets is the identification and authentication of the parties. This complexity is directly related to the definition of the nationality of the party to the legal relationship and the definition of national law to be applied. It is indicated that in the Russian Federation, this issue has been practically resolved with the creation of a Unified identification and authentication system. However, in international and interethnic relations, it still needs to be worked out. Several ways to solve the problem of unified legal regulation of relations involving the investment of digital financial assets are analyzed. There are four main models that currently exist. First of all, it concerns the convergence of the national laws of different states. The disadvantages of this approach are indicated. The second model is related to the creation of a unified international regulation. The arguments “for” and “against” are given. The problem of creating a polycentric or decentralized law is considered. The third model is related to the use of technical norms in the regulation of relations along with the legal ones. The fourth approach justifies the existence of two levels of regulation: external and internal. Conclusions: the authors have proposed the fifth model of the legal regulation of relations for the investment of digital financial assets, characterized by the legal regulation of individual objects of digital communication, a combination of external state regulation with self-regulation, as well as the possibility of creating an information platform for its own legal regulation within the system (the intra-system regulation or platform law). The problem of the existence of internal local regulation of legal relations for investing digital financial assets is analyzed. The conclusion is made about the formation of a local platform law. The polycentricity of the supra-platform law is substantiated. The problem of prohibiting the counter-provision of a digital financial asset is solved. It is proposed to replace this ban with a ban on the use of a digital financial asset as a means of payment.

Numerical simulation and experimental study of fluid–structure interactions in elastic structures based on the SPH method

The study of fluid–structure interactions in elastic structures is highly important in hydraulic structural engineering. This paper adopts the smooth particle hydrodynamics (SPH) coupling method to simulate dam failure water impact elastic plate flow and solid coupling problems. In addition, a numerical simulation is performed on the study of the free surface flow impact of the elastic plate structure on the main dynamic characteristics, including the impact force distribution and the change process. Additionally, the elastic structure of the vibration amplitude and frequency change rule, as well as the drastic changes in free surface flow, are also carried out. In this paper, the synchronous finite element algorithm is used to analyze the problem to obtain FEM results Additionally, two-dimensional benchmark physical tests are designed for dam-break water flow impacting an elastic plate are conducted, focusing on a comparative analysis of the numerical results of the SPH method with the results of physical tests and verifying the validity, accuracy, and superiority of the SPH coupling method for solving the problem of fluid‒solid coupling in elastic structures. On this basis, to explore the relevant physical quantities that cannot be measured or described during the test process, the flow–solid coupling characteristics of the elastic plate impacted by water flow are further understood by analyzing the nature of the flow field, the change in the flow–solid force of the elastic plate and the change rule of the frequency spectrum. The results show the following: (i) The jumps in velocity between the streams and the strong curvature of the free liquid surface lead to the creation of vortices at the cavities. (ii) The flow solid force under the impact of water flow increases and then decreases, and the smaller the deformation of the elastic structure is, the greater the force is. (iii) The vibration frequency of the fixed end of the elastic structure gradually decreases along the free end frequency, and the larger the deformation of the free end of the elastic plate is, the weaker its vibration response is. In addition, the natural frequency of the elastic plate under water flow impact is slightly lower than that under free vibration of the elastic plate. The related research results provide reference and guidance for the fluid–structure interaction problem.

LGMRec: Local and Global Graph Learning for Multimodal Recommendation

The multimodal recommendation has gradually become the infrastructure of online media platforms, enabling them to provide personalized service to users through a joint modeling of user historical behaviors (e.g., purchases, clicks) and item various modalities (e.g., visual and textual). The majority of existing studies typically focus on utilizing modal features or modal-related graph structure to learn user local interests. Nevertheless, these approaches encounter two limitations: (1) Shared updates of user ID embeddings result in the consequential coupling between collaboration and multimodal signals; (2) Lack of exploration into robust global user interests to alleviate the sparse interaction problems faced by local interest modeling. To address these issues, we propose a novel Local and Global Graph Learning-guided Multimodal Recommender (LGMRec), which jointly models local and global user interests. Specifically, we present a local graph embedding module to independently learn collaborative-related and modality-related embeddings of users and items with local topological relations. Moreover, a global hypergraph embedding module is designed to capture global user and item embeddings by modeling insightful global dependency relations. The global embeddings acquired within the hypergraph embedding space can then be combined with two decoupled local embeddings to improve the accuracy and robustness of recommendations. Extensive experiments conducted on three benchmark datasets demonstrate the superiority of our LGMRec over various state-of-the-art recommendation baselines, showcasing its effectiveness in modeling both local and global user interests.

Nonlinear ice sheet/liquid interaction in a channel with an obstruction

The interaction between the flow in a channel with an obstruction on the bottom and an elastic sheet representing the ice covering the liquid is considered for the case of steady flow. The mathematical model based on the velocity potential theory and the theory of thin elastic shells fully accounts for the nonlinear boundary conditions at the elastic sheet/liquid interface and on the bottom of the channel. The integral hodograph method is employed to derive the complex velocity potential of the flow, which contains the velocity magnitude at the interface in explicit form. This allows one to formulate the coupled ice/liquid interaction problem and reduce it to a system of nonlinear equations in the unknown magnitude of the velocity at the interface. Case studies are carried out for a semi-circular obstruction on the bottom of the channel. Three flow regimes are studied: a subcritical regime, for which the interface deflection decays upstream and downstream; an ice supercritical and channel subcritical regime, for which two waves of different lengths may exist; and a channel supercritical regime, for which the elastic wave is found to extend downstream to infinity. All these regimes are in full agreement with the dispersion equation. The obtained results demonstrate a strongly nonlinear interaction between the elastic and the gravity wave near the first critical Froude number where their lengths approach each other. The interface shape, the bending moment and the pressure along the interface are presented for wide ranges of the Froude number and the obstruction height.

A Weakly Nonlinear System for Waves and Sheared Currents over Variable Bathymetry

The wave–current–seabed interaction problem is studied by using a coupled-mode system developed for modeling wave scattering by non-homogeneous, sheared currents in variable bathymetry regions. The model is based on a modal series expansion of wave velocity based on vertical eigenfunctions, dependent on local depth and flow parameters, including propagating and evanescent modes. The latter representation is able to accurately satisfy the wave flow continuity condition and the no-entrance boundary condition on the sloping parts of the seabed. A new derivation of a simplified nonlinear system is introduced using decomposition to a mean flow and a perturbative wave field. To force the system to consider incoming waves at the inlet, boundary knowledge of periodic, travelling nonlinear water waves over a flat bottom is required. For this purpose, specific solutions are derived using the semi-analytical method based on the stream function formulation, for cases of water waves propagating above linearly and exponentially sheared currents. Results obtained by the application of the CMS concerning the propagation of waves and currents—in particular, examples characterized by depth inhomogeneities—are presented and discussed, illustrating the applicability and performance of the method.

Dynamic Amplification of Railway Bridges under Varying Wagon Pass Frequencies

Train configurations give rise to a primary wagon pass forcing frequency and their multiples. When any one of these frequencies coincides with the natural frequency of vibration of the bridge, a resonant response can occur. This condition can amplify the dynamic response of the bridge, leading to increased levels of displacement, stresses and acceleration. Increased stress levels on critical bridge structural elements increases the rate at which fatigue damage accumulates. Increased bridge acceleration levels can affect passenger comfort, noise levels, and can also compromise train safety. For older bridges the effects of fatigue, and being able to predict the remaining life, has become a primary concern for bridge engineers. Better understanding of the sensitivity of fatigue damage to the characteristics of the passing train will lead to more accurate remaining life predictions and can also help to identify optimal train speeds for a given train–bridge configuration. In this paper, a mathematical model which enables the dynamic response of railway bridges to be assessed for different train configurations is presented. The model is based on the well established closed from solution of the Euler–Bernoulli Beam (EBB) model, for a series of moving loads, using the inverse Laplace–Carson transform. In this work the methodology is adapted to allow different train configurations to be easily implemented into the formulation in a generalised form. A generalised equation, which captures the primary wagon pass frequency for any train configuration, is developed and verified by presenting the results of the bridge response in the frequency domain. The model, and the accuracy of the equation for predicting the primary wagon pass frequency, is verified using independently obtained measured field train–bridge response data. The main emphasis of this work is to enable the practicing engineer, railway operators and bridge asset owners, to easily and efficiently make an initial assessment of dynamic amplification, and the optimal train speeds, for a given bridge and train configuration. This is visually presented in this work using a Campbell diagram, which shows dynamic amplification and compares this with those calculated based on the design code, across a range of train speeds. The diagram is able to identify train speeds at which a resonance response can occur, and the wagon pass frequency, or its multiples, which are causing the increased dynamic amplification. The model is implemented in Matlab and demonstrated by analysing a range of short- to medium-single span simply supported plate girder railway bridges, typically found on the UK railway network, using the standard BS-5400 train configurations. The model does not consider the effects of the train mass and suspension system as this would require a non-closed form numerical solution of the problem which is not practical for the purposes of an initial assessment of the train–bridge interaction problem.

Pathologies in the Asymptotics of low-Froude Free-surface Waves Over Smooth Bodies

In the study of low-speed or low-Froude flows of a potential gravity-driven fluid past a wave-generating object, the traditional asymptotic expansion in powers of the Froude number predicts a waveless free-surface at every order. This is due to the fact that the waves are, in fact, exponentially small and beyond-all-orders of the naive expansion. The theory of exponential asymptotics indicates that such exponentially-small water waves are switched-on across so-called Stokes lines—these curves partition the fluid-domain into wave-free regions and regions with waves. In prior studies, Stokes lines are associated with singularities in the flow field, such as stagnation points, or corners of submerged objects or rough beds. In this work, we present a smoothed geometry that was recently highlighted by Pethiyagoda et al. [Int. J. Numer. Meth. Fluids. 2018; 86:607–624] as capable of producing waves, yet paradoxically exhibiting no obvious Stokes line according to conventional exponential asymptotics theory. In this work, we demonstrate that the Stokes line for this smooth geometry originates from an essential singularity at infinity in the analytic continuation of free-surface quantities. We discuss some of the difficulties in extending the typical methodology of exponential asymptotics to general wave-structure interaction problems with smooth geometries.

Operational cost and wind power integration capacities of the integrated heat and power dispatch (IHPD) system under different heating regulation modes and time steps

The utilization of the district heating system (DHS) thermal inertia is greatly influenced by heating regulation modes and time steps, however, which has been rarely analysed in almost all integrated heat and power dispatch system (IHPD) models, for the purpose of wind power integration. In this study, an IHPD model considering the thermal inertia of the DHS was established, in which a data interaction problem amongst the power sources, heat sources and district heating networks was solved. Thereafter, four most commonly used heating operation modes and different heating regulation time steps were applied to the IHPD model, respectively, to analyse and compare their effects on the IHPD system under different operation conditions, mainly considering the operation cost and the wind power integration. Results of the case studies showed that the variable flow and variable supply temperature mode produced the lowest operation cost of the IHPD system during a whole heating season. Consequently, this mode is recommended to be applied in the optimization operation of the IHPD system with the wind power integration. Meanwhile, a heating regulation time step within 3 h could make full use of the DHS thermal inertia, thus to improve the operational flexibility of the IHPD system.

Modeling of transportation and technological processes in automated systems

The purpose of the study is to create a problem-oriented model of transport and technological processes in automated systems. To achieve this goal, it is necessary to develop methodological aspects of creating an automated modeling system. The content of the basic principles of problem-oriented modeling in the study of an integrated automated system for managing stocks and transport and technological processes is revealed in the paper. At the same time, methodological aspects of creating automated modeling systems, namely, a conceptual mathematical model for the analysis and standardization of technical and economic indicators are considered. The functioning of logistics systems, namely, system modeling (supply — transport) is also considered. The problems of interaction and relationships, optimization of resource flows, and increasing the efficiency of management decisions making have been solved. It is shown that modeling resource flows involves adjustments through iterative redistribution of interregional and intraregional supplies among suppliers and consumers. Combining product items into one delivery leads to savings in stocks formation costs by reducing the number of orders. To create effective automated control systems, it is necessary to study in detail the primary object — the logistics and technical support system itself. The creation of applied mathematical and software is a promising direction for solving this problem and developing it as an automated modeling system. In this regard, when creating such automated control systems, it is most advisable to use a model-oriented approach, which is based on the principles of system analysis, standardization, classification and modularity. Thus, it is shown that the use of the problem-oriented approach to creating an automated modeling system makes it possible to reduce the labor intensity of its development and implementation, to provide the opportunity to unify algorithms for solving a problem, but also to apply standard methods for processing experimental results.

Coupling of the immersed boundary and Fourier pseudo-spectral methods applied to solve fluid–structure interaction problems

The current manuscript addresses fluid–structure interaction (FSI) problems to the analysis of vortex-induced vibration (VIV), employing the methodology designated as IMERSPEC2D. The approach seamlessly integrates the Fourier pseudo-spectral method (FPSM) and the immersed boundary method (IBM) to solve the Navier–Stokes (NS) and continuity equations. Simultaneously, the effects of cylindrical structure, involving 1 and 2 degrees of freedom (d.o.f.) are simulated, by incorporating structural motion equations into NS via the IBM source term and implementing a two-way FSI algorithm. In the paper are presented the comparison of low and high-order temporal integration methods applied to solve the dynamic behavior of the structure and the dimensionless of the cylinder’s structural motion equations, resulting in an increase in computational time step from 1E(-9\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-9$$\\end{document}) to 1E(-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-3$$\\end{document}). Validation results to refined mesh simulations include the accurate representation of the lock-in phenomenon to simulations of 1 d.o.f. obtaining the range between reduced velocity 5.456 and 5.568 and the maximal amplitude is 0.352. Notably, the eight-shape pattern of the 2 d.o.f. cylinder displacement is obtained and the formation of C2S wake patterns is achieved, as presented by other authors. In conclusion, the dimensionless approach reduces computational time, while the high-order both of IMERSPEC methodology and time advancement integration to FSI improve the results of the cylinder’s motion and alters distinct vortex shedding patterns in fluid dynamics.

Exploiting multimodal synthetic data for egocentric human-object interaction detection in an industrial scenario

In this paper, we tackle the problem of Egocentric Human-Object Interaction (EHOI) detection in an industrial setting. To overcome the lack of public datasets in this context, we propose a pipeline and a tool for generating synthetic images of EHOIs paired with several annotations and data signals (e.g., depth maps or segmentation masks). Using the proposed pipeline, we present EgoISM-HOI a new multimodal dataset composed of synthetic EHOI images in an industrial environment with rich annotations of hands and objects. To demonstrate the utility and effectiveness of synthetic EHOI data produced by the proposed tool, we designed a new method that predicts and combines different multimodal signals to detect EHOIs in RGB images. Our study shows that exploiting synthetic data to pre-train the proposed method significantly improves performance when tested on real-world data. Moreover, to fully understand the usefulness of our method, we conducted an in-depth analysis in which we compared and highlighted the superiority of the proposed approach over different state-of-the-art class-agnostic methods. To support research in this field, we publicly release the datasets, source code, and pre-trained models at https://iplab.dmi.unict.it/egoism-hoi.

Strategic triangle ‘Russia — India — China’: Structure and problems of interaction

A contemporary world order is based on an increasingly complex system of interstate relations, which implies the need to thoroughly consider the international context, even when analyzing bilateral interactions. From this point of view, the concept of a ‘strategic triangle’, developed during the Cold War and applied primarily to analyze the dynamics of relationships between the USSR, the USA and the PRC, appears to have significant epistemological potential. In current conditions, it is of particular interest to use this concept to study the logic of relations in the ‘Russia–India–China’ (RIC) triangle. This research pursues two interrelated goals. On the one hand, it is aimed at identifying specific features of this new ‘strategic triangle’, its inner structure and logic of interactions between its participants. On the other hand, it assesses the applicability of the theoretical models developed during the Cold War to the relations within the framework of the RIC strategic triangle. The author examines the history, general dynamics and contemporary features of interaction within each pair of bilateral relations in this ‘triangle’. The research has confirmed the hypothesis that the relations between Russia, India, and China, indeed, form a specific subsystem of international relations, which can be described as a ‘strategic triangle’. At the same time, unlike the Sino-American-Soviet ‘strategic triangle’, it is the logic of cooperation, rather than rivalry, which generally prevails within the framework of the RIC.However, the RIC ‘triangle’ can also be described as an inherently inconsistent system. While China and Russia maintain close strategic cooperation in almost all areas, in the case of India and Russia, economic cooperation does not match the achieved level of political contacts, and Sino-Indian relations, despite the generally positive dynamics during the recent years, remain at a low level. All this points to the need to develop a new theoretical and methodological framework for analyzing trilateral relations between Russia, India and China as a special subsystem of the contemporary world politics, one that will be free from Cold War stereotypes.

Effect of prenatal stressful life event exposure on child emotional and behavioral problem at age 2-6 years

Objective: To investigate the influence of prenatal stressful life event (SLE) exposure on child emotional and behavioral problem at age 2-6 years and identify the most risk exposure period. Methods: A total of 2 524 mother-child pairs were selected from Shanghai Maternal-Child Pairs Cohort based on pregnant women form 2016 to 2018 in Shanghai. Prenatal SLE exposure was assessed by Life Events Scale for Pregnant Women Questionnaire during the first and third trimester of pregnancy. Child emotional and behavioral problem was evaluated by Strengths and Difficulties Questionnaire at age 2-6 years. Multivariate binary logistic regression model and generalized estimating equation were conducted to quantify the association between prenatal SLE exposure and child emotional and behavioral problem at age 2-6 years, and identify the pregnancy period with strongest adverse effect. Results: The 2 524 mother-child pairs were divided into 4 groups: group with consistent low exposure to SLE (61.8%), group with high exposure to SLE in the first trimester (13.2%), group with high exposure to SLE in the third trimester (13.2%) and group with consistent high exposure to SLE (11.8%). The detection rates of emotional problem, hyperactivity, peer interaction problem and total difficulty score in children aged 3-6 years were highest in the group with consistent high exposure to SLE. Generalized estimating equation analysis showed that after controlling the confounding factors, compared with the consistent low exposure group, the children in the group with high exposure to SLE in the first trimester had significant increased risk for conduct problem at age 2-6 years (aOR=1.41, 95%CI:1.07-1.87). The children in the group with consistent high exposure to SLE were at increased risk for emotional problem, peer interaction problem, and high total difficulty score with the aOR of 1.41 (95%CI: 1.09-1.83), 1.46 (95%CI: 1.15-1.86) and 1.51(95%CI: 1.17-1.93). Conclusion: These findings indicated that prenatal exposure to SLE have adverse effect on child emotional and behavioral problem at age 2-6 years, especially the exposure in the first trimester.

Analysis of influencing factors of penetration mechanism and vertical bearing characteristics of monopile in calcareous sand: Laboratory model testing and in-situ testing

The construction of islands and reef engineering structures in marine environments has been a hot topic in recent years, and calcareous sand, which possesses unique physical properties, is widely distributed on islands and reefs. Due to the properties of calcareous sand, engineering problems such as pile slipping while driving and a low bearing capacity during service can occur. To address the key problem of pile‒soil interactions in calcareous sand foundations, laboratory model and in situ tests were conducted, accounting for factors such as impact energy, relative density, pile-forming method, and pile aspect ratio. First, the penetration mechanism of hammered piles in calcareous sand was studied. Then, the differences in vertical bearing characteristics between hammered and pre-embedded piles under different conditions were explored. The pile driving test results showed that a higher impact energy and lower relative density are more conducive to pile sinking. Moreover, as the number of hammer drops and dynamic penetration resistance increase with increasing burial depth, the pile tip resistance is the main factor limiting pile penetration in calcareous sand. The vertical static loading test revealed that particle breakage accelerates soil redistribution around the pile and that compaction enhances the bearing capacity of the pile. The pile aspect ratio, relative density and pile-forming method also play major roles in the vertical bearing capacity of piles in calcareous sand. In addition, the skin friction of a pile rapidly increases to the ultimate value along a multisegment trend of polyline functions. Similarly, the pile tip resistance rapidly increases at the initial loading stage, exhibiting the behavior of an end-bearing pile. The in situ test results indicated that the pile penetration depth in coral calcareous sand is an important factor affecting the bearing capacity.