Научный архив: статьи

Introduction/purpose: The application of virtual reality (VR) and simulation technologies in military training offers cost-effective and versatile approach to training enhancement. However, prevalence of cybersickness (CS), characterized by symptoms such as nausea, limits their widespread use.

Methods: This study introduces objective parameters for the detection of CS using three-channel electrogastrogram (EGG) recording from one specific subject and assesses the independence and linear correlation for appropriate channel selection. The paper employs a 3-level discrete wavelet transformation (DWT) on the chosen channel to identify key parameters indicative of gastric disturbances. Furthermore, the paper investigates recovery from CS following VR and examines the application of unsupervised machine learning (ML) for segmenting EGG into baseline and CS, utilizing significant features previously identified.

Results and discussion: The analysis reveals no significant differences across EGG channels and moderate to low linear correlation between channel pairs. The feature selection demonstrates that the root mean square of the amplitude as well as the maximum and mean values of the power spectral density (PSD) calculated on all DWT coefficients, are effective for CS detection while the dominant EGG scale could not indicate CS for any level of decomposition. Furthermore, recovery signs appear approximately 8 minutes after the first VR experience supporting the idea of conducting multiple sessions the same day i. e., intensive VR-based training.

Conclusions: The unsupervised ML shows potential in identifying CSaffected EGG signal segments with feature extraction based on DWT, offering a novel approach for enhancing the prevention of CS occurrence in VR-based military training and other VR-related environments.

Introduction/purpose: Temperature and time-dependent effects such as concrete shrinkage and creep significantly affect the behavior of steel-concrete composite beams. Hence, taking into account the demands brought by these additional effects is necessary. This necessity has resulted in various theoretical and numerical research studies. This article proposes an analytical tool capable of predicting a new redistribution of stresses brought by the combined action of temperature and concrete shrinkage in composite steel-concrete beams in partial shear connection. In this work, the partial shear connection at the steel-concrete interface is taken into account according to the degree of connection (N/Nf).

Methods: This involves reformulating the model proposed in 2024 by Rahal et al analyzing the behavior of composite steel-concrete beams in full shear connection under the effect of temperature and concrete shrinkage. In this present study, the main contribution is the introduction of the effect of the connection degree (N/Nf) at the steel-concrete interface, thus leading to an analytical model capable of predicting additional stresses brought by shrinkage and temperature in composite steel-concrete beams in partial shear connection.

Results: When referred to the model proposed in 2024 by Rahal et al, the results from this current approach are satisfactory. They clearly show that the degree of connection significantly affects the forces brought about by the combined action of concrete shrinkage and temperature.

Conclusion: The results of the present approach and those of the existing model developed by Rahal et al are in good agreement. They clearly show the effect of concrete shrinkage and temperature as a function of the connection degree N/Nf on the behavior of composite steel-concrete beams.

This study aims to investigate the impact of avatar identification on the intention to share by examining the mediating role of user immersion and the moderating effect of perceived social distance. For this, we collected 228 higher education students in South Korea through a survey and used hierarchical regression with SPSS 24.0. In the results, first, it showed that participants who perceived higher levels of similarity identification, wishful identification, and embodied presence in their avatars in the metaverse platform were more immersed in their avatars. Second, participants who perceived greater embodied presence in their avatars had a stronger intention to share their avatars through immersion. Finally, the positive relationship between perceived embodied presence and immersion was more significant for participants in metaverse platforms with higher perceived social distance compared to those with lower perceived social distance. This study is the first to examine the integral model of avatar identification factors in the metaverse platform. And, this study’s results show the mechanism by which avatar identification enhances the intention to share.

A simple method is proposed to estimate the dynamic yield stress of materials using modified Taylor tests for high-velocity impact of profiled cylinders with a reduced diameter of the head part. Assuming the uniformity of deformations and stresses in the head part, formulas are derived for estimating the yield stress and strain rate from the change in the length of the reduced head part, as well as the mass of the sample and the impact velocity. This estimation is verified by comparison with the results of numerical calculations by the SPH method based on the dislocation plasticity model parameterized for cold-rolled oxygen-free copper. It is shown that the stopping time of the sample and the strain rate are reproduced with good accuracy, and the shear strength estimate gives an error that increases with the impact velocity. At velocities that do not lead to deformation of a wide part of the sample (up to 90 m/s in the case under consideration), the error increases linearly up to 30%, which can be taken into account by a correction factor. The proposed estimate, taking into account the correction factor, was applied to analyze the results of previous experiments; the obtained values correspond to the literature data on the rate dependence of the shear strength.

In this work we theoretically analyze the electromagnetic behavior of graphene-based metasurface, consisting on arranged array of graphene stripes, under attenuated total reflection conditions. We investigate surface plasmon-polaritons excitation at terahertz and sub-terahertz frequencies. We show that surface plasmon-polaritons may be excited in the metasurface for some orientation with respect to incident wave plane. Effectivity of surface plasmon-polaritons excitation depends on graphene chemical potential and graphene stripes width. We believe that our results open a new road for graphene metasurface based terahertz devices, such as modulator

Rossiya-Ukraina mojarosining kuchayishi va Rossiyaga qarshi G’arbning keyingi sanktsiyalari Evroosiyo aloqasiga chuqur va keng qamrovli ta’sir ko’rsatdi. Bir tomondan, ushbu holatlar Shimoliy va Markaziy Evroosiyo koridorlarining Xitoy va Evropa o’rtasidagi tranzit yo’llari rolini sezilarli darajada kamaytirdi va dengiz transportiga geosiyosiy omillar ham tahdid solmoqda. Shu bilan birga, Rossiya-Evropa energetika savdo tarmog’i va infratuzilma aloqalari muhim o’zgarishlarga duch kelmoqda, neft va gaz quvurlari tez-tez siyosiylashtirilib, ularga qarshi turish va tahdid qilish kabi maqsadlarda foydalaniladi va shu bilan Evroosiyo aloqasi xavfsizligini buzadi. Boshqa tomondan, bu geosiyosiy o’zgarishlar, shuningdek, Rossiya va Belarus kabi Xitoy va Yevroosiyo iqtisodiy Ittifoqi (EAEU) mamlakatlari o’rtasidagi hamkorlikni chuqurlashtirish, Trans-Kaspiy xalqaro Transport yo’nalishi (TITR, o’rta koridor), Xitoy-Qirg’iziston-Ikkinchi O’rta yo’lakning bir qismi sifatida O’zbekiston temir yo’li va xalqaro Shimoliy-Janubiy Transport yo’lagi (INSTC). Ushbu fonda Rossiya, Xitoy, Qo’shma Shtatlar va Evropa har biri o’zlarining ulanish strategiyalarini ishlab chiqdilar, bu Evroosiyo ichidagi turli sub-mintaqalarning geosiyosiy dinamikasiga qarab “ulanish urushlari” yoki hamkorlikdagi tarmoq qurilishining turli xil o’zaro ta’sir stsenariylariga olib keldi. Shu nuqtai nazardan, Markaziy Osiyoning Evroosiyo ulanishidagi hal qiluvchi roli tobora ommalashib bormoqda va uni Evroosiyo ichida yangi ulanish markazi sifatida paydo bo’lishi va butun qit’ani qamrab oladigan ulanish tarmog’ini qurishga rahbarlik qilmoqda.

Jahon iqtisodiyoti va diplomatiya universitetida energetik diplomatiya va geosiyosat markazi tashkil etilgan bo’lib, u O’zbekistonning barqaror rivojlanishi va mamlakat milliy manfaatlarini xalqaro maydonda ilgari surish uchun nafaqat ilmiy-nazariy, balki amaliy ahamiyatga ega tizimli tadqiqotlar olib borishga mo’ljallangan.

Ushbu “Yevropa bozoriga qanday eksport qilish kerak” jamoaviy monografiyasi asosan Jahon iqtisodiyoti va diplomatiya universiteti olimlari tomonidan “Toshkent Jan Monnet Yevropa tadqiqotlari mukammallik markazi” loyihasi homiyligida tayyorlangan (O’zbekiston Respublikasi oliy majlisi qonunchilik palatasi, xalq deputatlari viloyat, tuman va shahar kengashlariga qarashli 620528-EPP).-1-2020-1- UZ-EPPJMO-CoE)“EI ERASMUS + dasturi tomonidan qo’llab-quvvatlanadi.

Ushbu tadqiqot maqolasi Markaziy Osiyo mintaqasi doirasida O’zbekistonning murakkab energetika tizimini o’rganadi. Tahlil mamlakatning Markaziy Osiyo energetik landshaftini shakllantirishdagi rolini yorituvchi iqtisodiy faktlar, ta’sir etuvchi omillar va istiqbollarni qamrab oladi. Maqola O’zbekistonning energetika resurslari, infratuzilmasi va siyosatiga e’tibor qaratib, mamlakatning mintaqaviy energetika tizimidagi o’rnini har tomonlama tushunishga qaratilgan

Статья посвящена научной проработке управленческого инструментария ESG-менеджмента, несформированность которого препятствует практической реализации этого управленческого подхода к обеспечению устойчивого развития бизнеса. Для этого автором осуществляется регрессионное моделирование зависимости результатов управления, относящихся к устойчивости бизнеса, от применения управленческих инструментов с опорой на передовой международный опыт стран, являющихся глобальными лидерами в области ESG-менеджмента в 2023 г. В результате определен перспективный инструментария ESG-менеджмента, в состав которого вошло наращение объема финансирования менеджмента и повышение уровня управленческого образования. Раскрыта перспектива устойчивого развития бизнеса в России через совершенствование практики ESG-менеджмента, практическая значимость которой выражена в том, что она повышает точность планирования и прогнозирования управления устойчивостью отечественного бизнеса в период до 2030 г. Предложены практические рекомендации по применению сформированного управленческого инструментария, которые позволят повысить эффективность ESG-менеджмента в России в поддержку устойчивости отечественного бизнеса.

The Elgar Encyclopaedia of Cross-Cultural Management is a series of chapters written by academic experts on the study of culture in world business management. Edited by Professor Audra Mockaitis of Maynooth University in Ireland and Professor Christina Butler of Kingston Business School in Kingston University in the UK, the articles are written by seventy-eight university teachers from all over the world examining international business cultural management issues. The book contains 77 chapters, some as short as two pages long, and examines the role of cultural understanding in international business management, each chapter containing references to sources at the end.

The article considers extreme tourism, its definition, history of origin, species, directions, classifications. The issue of its development, popularity in Russia and all its aspects. All work is carried out on the basis of official scientific articles. According to the results of analysis of the information, conclusions are made about the course of extreme tourism in the future, its prospects in our country. To sum up the results, we can say that in Russia there are many prerequisites for the development of extreme tourism. The weather and climate allow, the state increasingly supports this kind of recreation, scientific infrastructures are increasingly paying more attention to such tourism. And the main factor of development is people: The more people want to be in the tone and spend a breath of time, the more extreme tourism will develop. Here, too, everything depends on us.