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A review of the various applications and security issues in IoT and its future aspects

International Journal of Security and Networks 2024年第3期19卷 109-127页

作者： Chopra, Sumit Bains, Gagandeep Singh Kaur, Simranjot Sharma, Rajesh Nayyar, Anchal School of Engineering Design and Automation GNA University Punjab Phagwara India School of Computational Science GNA University Punjab Phagwara India

In the era of the internet revolutionaries’ physical objects exchange data through technology. As a result, there is an exponential increase in the number of devices now connected to the internet. Devices such as smart televisions, smartphones and smartwatches are now common in nearly every household across the world. However, their battery life and data security mainly depend on the protocols used for data exchange. Also, the modern lifestyle is largely dependent on the internet of things (IoT) for daily tasks, hence the security of confidential data becomes an important issue, and in this paper, we are going to discuss IoT in detail explaining, how IoT works, along with its architecture, applications, and challenges it faces when it comes in terms of cyber security. In addition to this, the paper covers an overview of case studies where security has been compromised in IoT in previous years. Also, this paper discusses the future aspects that can help us make better and more secure IoT devices. Finally, it will cover the various security threats and counter measures in different layers of IoT network. Copyright © 2024 Inderscience Enterprises Ltd.

关键词： Fog computing

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Unlocking power of neighboring vacancies in boosting hydrogen evolution reactions on two-dimensional NiPS3 monolayer

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eScience 2024年第3期4卷 104-115页

作者： Hyun Gu Han Jae Won Choi Minsu Son Ki Chul Kim Computational Materials Design Laboratory Department of Chemical EngineeringKonkuk UniversitySeoul 05029The Republic of Korea Division of Chemical Engineering Konkuk UniversitySeoul 05029The Republic of Korea

This study investigates the effect of defect engineering on the catalytic activity of a NiPS3 monolayer catalyst for the hydrogen evolution reaction(HER).Three different types of vacancies on the basal plane of the monolayer are explored through a multi-step mechanism involving the dissociative adsorption of a water molecule and subsequent electrochemical adsorption of the dissociated ***-formation of vacancies in both Ni and S sites is found to be the most effective in enhancing the catalytic performance of the monolayer.A key resource for the reaction thermodynamics is the S-substitution-like physisorption of a water molecule on a vacant S site,followed by the dissociative occupation of OH and H into vacant sites of S and Ni elements,boosted by the NiS di-vacancy configuration with low activation energy *** reveals the highest contribution of bonding orbitals to the monolayer-H bond makes it the most desirable defect engineering approach for transition metal phosphorus chalcogenides with high HER ***,this study highlights the significance of controlled defect engineering in augmenting the catalytic performance of NiPS3 monolayer catalysts for HER.

关键词： Hydrogen evolution reaction Defect engineering Transition metal phosphorus trichalcogenide Density functional theory Reaction thermodynamics

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Numerical analysis of the correlation between fluid dynamic modes and hydrodynamic noise in flows around a three-dimensional circular cylinder

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Journal of Hydrodynamics 2024年第1期36卷 119-129页

作者： Jia-jia Qin Ming-xin Zou Yuan Zhuang De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Wuhan Second Ship Design and Research Institute Wuhan430205China

The flow around a circular cylinder for Re=1000 is characterized by flow separation and Karman vortex *** typical flow features can be captured to study the correlation between fluid fields and sound *** this paper,the three-dimensional circular cylinder is taken as the research object,and the probes of surface fluctuating pressure and far field sound pressure are arranged every 10°.The directional diagram and the coherence of fluctuating pressure and sound pressure are *** relationship between the flow mode and hydrodynamic noise is studied by using dynamic mode decomposition(DMD).The characteristics of the dipole and quadrupole sound source term of a long span cylinder are *** results show that at the angles between 30°–120°and 190°–350°,the fluctuating pressure contributes more to the generation of dipole *** quadrupole sound source shows three-dimensional effects,which is more obvious in a cylinder with large spanwise length.

关键词： Pressure coherence dynamic mode decomposition flow-sound correlation circular cylinder

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360-Degree Tri-Modal Scanning: engineering a Modular Multi-Sensor Platform for Semantic Enrichment of BIM Models

360-Degree Tri-Modal Scanning: Engineering a Modular Multi-S...

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2024 ISPRS Technical Commission I Mid-term Symposium on Intelligent Sensing and Remote Sensing Application

作者： Collins, Fiona C. Noichl, Florian Slepicka, Martin Cones, Gerda Borrmann, André Chair of Computational Modeling and Simulation School of Engineering and Design Technical University of Munich Munich80333 Germany

Point clouds, image data, and corresponding processing algorithms are intensively investigated to create and enrich Building Information Models (BIM) with as-is information and maintain their value across the building lifecycle. Point clouds can be captured using LiDAR and enriched with color information from images. Complementary to such dual-sensor systems, thermography captures the infrared light spectrum, giving insight into the temperature distribution on an object’s surface and allowing a diagnosis of the as-is energetic health of buildings beyond what humans can see. Although the three sensor modes are commonly used in pair-wise combinations, only a few systems leveraging the power of tri-modal sensor fusion have been proposed. This paper introduces a sensor system comprising LiDAR, RGB, and a radiometric thermal infrared sensor that can capture a 360-degree range through bi-axial rotation. The resulting tri-modal data is fused to a thermo-color point cloud from which temperature values are derived for a standard indoor building setting. Qualitative data analysis shows the potential for unlocking further object semantics in a state-of-the-art Scan-to-BIM pipeline. Furthermore, an outlook is provided on the cross-modal usage of semantic segmentation for automatic, accurate temperature calculations. © 2024 Fiona C. Collins et al.

关键词： Semantics

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Quantum spin Hall effect protected by spin U(1) quasisymmetry

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Physical Review B 2024年第16期110卷 L161104页

作者： Lu Liu Yuntian Liu Jiayu Li Hua Wu Qihang Liu Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE) Laboratory for Computational Physical Sciences (MOE) State Key Laboratory of Surface Physics and Department of Physics Shanghai Qi Zhi Institute Shanghai 200232 China Nanjing 210093 China Guangdong Provincial Key Laboratory of Computational Science and Material Design

Quantum spin Hall (QSH) insulators, with their unique helical edge states where counterpropagating edge channels possess opposite spins, have attracted broad interest across various fields. While the exact quantization of spin Hall conductance (SHC) is elusive in realistic materials due to intrinsic spin mixing effects, the near quantization, as a compromised definition of the QSH effect, cannot be captured by rigorous topological invariants. In this Letter, we present a universal symmetry indicator for diagnosing the QSH effect in realistic materials, termed spin U(1) quasisymmetry. Such a symmetry eliminates the first-order spin-mixing perturbation and thus protects the near-quantization of SHC, applicable to time-reversal-preserved cases with either Z2=1 or Z2=0, as well as time-reversal-broken scenarios. We propose that spin U(1) quasisymmetry is hidden in the subspace spanned by the doublets with unquenched orbital momentum and emerges when SOC is present, which can be realized in 19 crystallographic point groups. Our theory is applied to identify previously overlooked QSH phases such as time-reversal-preserved even spin Chern phase and time-reversal-broken phase, as exemplified by twisted bilayer transition metal dichalcogenides, monolayer RuBr3, and monolayer FeSe. Our work provides a comprehensive symmetry-based framework for understanding the QSH effect and significantly expands the material pool for the screening of exemplary material candidates.

关键词： Electronic structure First-principles calculations Symmetry protected topological states Topological materials Dichalcogenides Two-dimensional electron system Z_2 symmetry

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Advancing first-principles dielectric property prediction of complex microwave materials:an elemental-unit decomposition approach

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npj computational Materials 2024年第1期10卷 1408-1413页

作者： Yabei Wu Peihong Zhang Wenqing Zhang Department of Materials Science and Engineering and Guangdong Provincial Key Lab for Computational Science and Materials Design Southern University of Science and TechnologyShenzhenGuangdongChina Department of Physics University at BuffaloState University of New YorkBuffaloNYUSA

Tungsten-bronze-type material Ba_(6-3x)RE_(8+2x)Ti_(18)O_(54),(RE=rare earth elements)is an important microwave dielectric that has shown great promises for future miniaturization of microwave devices because of its high dielectric constant,low loss,and tunabilities,and there is still much room for *** their proven predictive power,first-principles calculations may greatly help accelerate materials optimization by reducing or eliminating the expensive and time-consuming experimental trial-and-error ***,microwave dielectrics such as the tungsten-bronzetype materials are rather complex systems with unit cells containing hundreds or thousands of atoms,making ab initio calculations prohibitively *** this work,we propose an elemental-unit decomposition(EUD)technique that can drastically reduce the computational effort of predicting the properties of complex microwave dielectrics and demonstrate its accuracy and *** approach facilitates first-principles prediction and design of complex microwave dielectric materials that would otherwise be extremely difficult.

关键词： microwave dielectric prediction

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Numerical investigations of focused wave interact with a moving cylinder

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Journal of Hydrodynamics 2023年第4期35卷 724-735页

作者： Yuan Zhuang Fu-chang Zhou Wen-jun Zhou De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Wuhan Second Ship Design and Research Institute Wuhan430205China Marine Design and Research Institute of China Shanghai200011China

This paper presents a numerical study on focused wave and current interactions with a *** cylinder is moving in the opposite direction to the wave *** effective computational decomposition method is adopted to reduce the calculation resources.A potential solver high-order spectral(HOS)method is applied to generate focused wave field,while our in-house computational fluid dynamics(CFD)solver naoe-FOAM-SJTU with overset grid takes the charge of achieving the viscous effect around the moving *** viscous domain moving with the cylinder thus the size and mesh grids in computational domain is greatly *** pressure on cylinder surface and wave fields around cylinder are compared with experimental data,shows a well ***,the scattering wave field and vortex shedding are *** the existence of moving cylinder,the classical scattering wave types are still observed.

关键词： Focused wave moving cylinder naoe-FOAM-SJTU solver computational decomposition method

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Transient Analysis of Graphene Reinforced FG-Porous Sandwich Plates Subjected to Underwater Blast 67th

Transient Analysis of Graphene Reinforced FG-Porous Sandwich...

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67th Congress of the Indian Society of Theoretical and Applied Mechanics, ISTAM 2022

作者： Shakir, Mohammed Talha, Mohammad Computational Design Lab School of Mechanical and Materials Engineering Indian Institute of Technology Mandi Himachal Pradesh Mandi175075 India

ISBN: (纸本)9789819704170

The present study performs the transient analysis of sandwich plates under the influence of underwater blast loading. The sandwich plate consists of a functionally graded (FG) porous core reinforced with graphene nanoplatelets (GnP), and two isotropic face sheets. To estimate the effective properties of the reinforced core, such as Young's modulus and mass density, the Halpin–Tsai model and rule of mixture are respectively utilized. The distribution of porosity and GnP employs continuous functions to accomplish gradation along the thickness direction. The governing equations based on the higher-order plate kinematic model are developed using a variational approach. The transient response in terms of nondimensional center displacement has been accessed by the finite element method along with Newmark’s time integration approach and the influence of various parameters such as porosity index, GnP’s weight fraction, type of porosity distribution, etc. is also explored. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Graphene

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Numerical analysis of turbulent fluctuations around an axisymmetric body of revolution based on wall-modeled large eddy simulations

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Journal of Hydrodynamics 2023年第6期35卷 1041-1051页

作者： Kang-jian He Fu-chang Zhou Wei-wen Zhao Jian-hua Wang De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Wuhan Second Ship Design and Research Institute Wuhan430205China

Wall-modeled large eddy simulation(WMLES)is used to investigate turbulent fluctuations around an axisymmetric body of *** study focuses on evaluating the ability of WMLES to predict the fluctuating flow over the axisymmetric hull and analyzing the evolution of turbulent fluctuations around the *** geometry is the DARPA SUBOFF bare model and the Reynolds number is 1.2×10^(7),based on the free-stream velocity and the length of the ***-wall flow structures and complex turbulent fluctuation fields are successfully ***-averaged flow quantities,such as time-averaged pressure and skin-friction coefficients,and time-averaged velocity profiles on the stern,achieved great agreements between WMLES results and experimental ***-similarity of time-averaged velocity defects within a self-similar coordinate up to twelve diameters from the tail.A comprehensive analysis of second-order statistics in the mid-body,stern,and wake regions is *** results agree well with experimental data and previous wall-resolved large eddy simulation(WRLES)results about root mean square(rms)of radial and axial fluctuating velocities at the *** fluctuations including turbulent kinetic energy(TKE)and second-order velocity statistics are identified as dual peak behavior and non-self-similar over the wake length,consistent with previous findings in the *** assessment enhances the understanding of WMLES capabilities in capturing complex fluctuating flow around axisymmetric geometries.

关键词： Turbulent fluctuations wall-modeled large eddy simulation(WMLES) turbulent boundary layer wake

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Assessment of subgrid-scale models in wall-modeled large-eddy simulations of turbulent channel flows

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Journal of Hydrodynamics 2023年第3期35卷 407-416页

作者： Wei-wen Zhao Fu-chang Zhou Guo-qing Fan De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Wuhan Second Ship Design and Research Institute Wuhan 430205China

Considering the demanding of grid requirements for high-Reynolds-number wall-bounded flow,the wall-modeled large-eddy simulation(WMLES)is an attractive method to deal with near wall ***,the effect of subgrid-scale(SGS)models for wall-bounded turbulent flow in combination with wall stress models is still *** this paper,turbulent channel flow at Reτ=1000 are numerically simulated by WMLES in conjunction with four different SGS models,i.e.,the wall-adapting local eddy-viscosity model,the dynamic Smagorinsky model,the dynamic SGS kinetic energy model and the dynamic Lagrangian *** mean velocity profiles are compared with the law of the wall,and the velocity fluctuations are compared with direct numerical simulation *** energy spectrum of velocity and wall pressure fluctuations are presented and the role of SGS models on predicting turbulent channel flow with WMLES is discussed.

关键词： Wall-modeled large-eddy simulation(WMLES) subgrid-scale(SGS)model turbulent channel flow energy spectra

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