Розробка та дослідження бази даних для систем обробки статистичної інформації

Дана стаття присвячена проблемам розробки та оптимізації специфічних баз даних. Проведено аналіз існуючих загальних підходів та методів оптимізації баз даних, обґрунтовано необхідність якісно іншого підходу в рамках специфічної проблематики оптимізації баз даних статистичної інформації. Запропоновано та проілюстровано реалізацію методу рішення поставленої задачі.Данная статья посвящена проблемам разработки и оптимизации специфических баз данных. Проведён анализ существующих общих методов и подходов к оптимизации баз данных, обоснована необходимость качественно иного подхода в рамках специфики проблематики оптимизации баз данных статистической информации. Предложена и проиллюстрирована реализация метода решения поставленной задачи.This article is devoted to problems of development and optimization of specific databases. The analysis of the existing general methods and approaches of database optimization has been given and the need for a qualitatively different approach within the specifics of optimizing statistical information databases has been justified. The implementation of the method of the problem solution has been proposed and illustrated

LiY(SO4_4)2_2: A Superionic Material Synthesized by Superionic State Hidden in no-Superionic Literature

A potential superionic material LiY(SO$_4$)$_2$ has been excavated from the published literatures because its synthesis method and experiment data implied it exists the superionic state. We use \textit{ab initio} calculation to analyzing the differences between solid state and superionic state. We found the diffusion of Li$^+$ from the lattice site to the interstitial site will change the nearest neighbor numbers of O atom from 4 to 8. In order to reduce energy, the reorientation of SO$_4^{2-}$ must exist accompany with the diffusion of Li$^+$ so the nearest neighbor number of O will keep about 5 in the superionic state. Our work not only presents an example for discovering materials from literatures based on prior knowledge but also reveals the micromechanism of cation-anion coupled dynamics for superionic state.Comment: 18pages 5figure

A Galerkin Finite Element Method for Numerical Solutions of the Modified Regularized Long Wave Equation

A Galerkin method for a modified regularized long wave equation is studied using finite elements in space, the Crank-Nicolson scheme, and the Runge-Kutta scheme in time. In addition, an extrapolation technique is used to transform a nonlinear system into a linear system in order to improve the time accuracy of this method. A Fourier stability analysis for the method is shown to be marginally stable. Three invariants of motion are investigated. Numerical experiments are presented to check the theoretical study of this method

Joint Precoding and Phase Shift Design in Reconfigurable Intelligent Surfaces-Assisted Secret Key Generation

Physical layer key generation (PLKG) is a promising technique to establish symmetric keys between resource-constrained legitimate users. However, PLKG suffers from a low key rate in harsh environments where channel randomness is limited. To address the problem, reconfigurable intelligent surfaces (RISs) are introduced to reshape the channels by controlling massive reflecting elements, which can provide more channel diversity. In this paper, we design a channel probing protocol to fully extract the randomness from the cascaded channel, i.e., the channels through reflecting elements. We derive the analytical expressions of the key rate and design a water-filling algorithm based on the Karush-Kuhn-Tucker (KKT) conditions to find the upper bound. To find the optimal precoding and phase shift matrices, we propose an algorithm based on the Grassmann manifold optimization methods. The system is evaluated in terms of the key rate, bit disagreement rate (BDR) and randomness. Simulation results show that our protocols significantly improve the key rate as compared to existing protocols. Compared to multiple-antennas systems without a RIS, our proposed method achieves an average 9.51 dB performance gain when the side length of an element is 1/4 wavelength and the Rician factor is 0 dB

Reconfigurable Intelligent Surface-Assisted Key Generation for Millimetre-Wave Multi-User Systems

Physical layer key generation (PLKG) leverages wireless channels to produce secret keys for legitimate users. However, in millimetre-wave (mmWave) frequency bands, the presence of blockage significantly reduces the key rate (KR) of a PLKG system. To address this issue, we introduce reconfigurable intelligent surfaces (RISs) as a potential solution for constructing RIS-reflected channels, thereby enhancing the KR. Our study focuses on the beam-domain channel model and exploits the sparsity of mmWave bands to enhance the randomness of secret keys. To relieve pilot overhead in multi-user systems, we employ a compressed sensing (CS) algorithm to estimate angular information and propose a channel probing protocol with the full-array configuration for acquiring the beam-domain channel. We derive the analytical expressions for the KR in the case of full-array configuration. To optimize the KR, we design the phase shift and precoding vectors based on the obtained angular information. Furthermore, we employ a water-filling algorithm that relies on the Karush-Kuhn-Tucker (KKT) conditions to optimize power allocation for estimating the beam-domain channel with the same channel variance. When channel variances of the beam-domain channel differ, we design a deep-learning-based power allocation method for a more complex problem. What is more, we design a sub-array configuration scheme that exploits the difference in spatial angles between users to reduce pilot overhead and derive the analytical expression for the KR. Through extensive simulations, we demonstrate that our proposed PLKG schemes outperform existing methods

Karst landslides detection and monitoring with multiple SAR data and multi-dimensional SBAS technique in Shuicheng, Guizhou, China

Shuicheng District is a karst mountain area, located in Guizhou Province, China. Its fragile stratum and frequent underground mining activities makes it prone to landslides. Owning to its wide coverage and frequent revisit, the InSAR technology has advantages in potential landslide identification and deformation monitor. However, affected by dense vegetation and atmospheric delay, it is much difficult to get sufficient effective targets to derive the deformation in this area. Besides, deformation derived from single orbit SAR data can result in the missing identification of some potential landslides and the misinterpreting of the real kinematics process of landslides. In this study, the multi-source SAR data, atmospheric error correction by quadratic tree image segmentation method, and phase-stacking method were selected to derive the surface deformation of this area. Besides, DS-InSAR and MSBAS method were combined to derive the deformation of Pingdi landslide. First, the potential landslides in this area were identified, surface deformation result, optical remote sensing images and geomorphological features were jointly considered. Then, the landslide distribution characteristics was analyzed in terms of slope, elevation and stratum. After that, the deformation along the LOS direction was acquired using the DS-InSAR method. The MSBAS method was used to retrieve the two-dimensional deformation of Pingdi landslide. Finally, the comprehensive analysis of triggering factors and failure process were conducted according to the spatial-temporal deformation characteristics and field investigation. The results indicated that landslides in Shuicheng district were mostly located in the junction of T1 and P3 stratum and mining related. Mining activity was the main cause of the Pingdi landslide deformation, the precipitation was the driving factor of the landslide instability. The research provides an insight into the explore the unstable slope distribution characteristic and the failure process of the landslides

The tone atlas of perceptual discriminability and perceptual distance: Four tone languages and five language groups

Available online 4 April 2022Some prior investigations suggest that tone perception is flexible, reasonably independent of native phonology, whereas others suggest it is constrained by native phonology. We address this issue in a systematic and comprehensive investigation of adult tone perception. Sampling from diverse tone and non-tone speaking communities, we tested discrimination of the three major tone systems (Cantonese, Thai, Mandarin) that dominate the tone perception literature, in relation to native language and language experience as well as stimulus variation (tone properties, presentation order, pitch cues) using linear mixed effect modelling and multidimensional scaling. There was an overall discrimination advantage for tone language speakers and for native tones. However, language- and tone-specific effects, and presentation order effects also emerged. Thus, over and above native phonology, stimulus variation exerts a powerful influence on tone discrimination. This study provides a tone atlas, a reference guide to inform empirical studies of tone sensitivity, both retrospectively and prospectively.Project conception (dB), and project management and data collection by the sixth author, BK, at the MARCS Institute for Brain, Behaviour and Development in Sydney Australia were supported by Australian Research Council Discovery Project grants (DP0988201, DP110105123) to the final author, dB. Data collection in Hong Kong was supported by Dr. Stanley Ho Medical Development Foundation. Data collection at the National University of Singapore was supported by an ODPRT grant for research excellence to LS. LL’s writing was supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 798658 hosted by Center for Multilingualism across the Lifespan at the University of Oslo, financed by Research Council of Norway through its Centers of Excellence funding scheme grant agreement No. 223265. MK’s writing was supported by the Basque Government through the BERC 2018-2021 program, by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship, PID2019-105528GA-I00, and by the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation CEX2020-001010-S. We would like to thank Kay Wong for data collection in Hong Kong, Ms. Juthatip Duangmal and Ms. Nawasri Chonmahatrakul at MARCS-CILS NokHook BabyLab, Thammasat University for data collection in Thailand, Charlene Fu and Dilu Wewalaarachchi for data collection in Singapore; and Antonia Götz for discussions about analyses in R