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Analysis of network instantaneous availability based on percolation theory

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Analysis of network instantaneous availability based on perc...

Direct visualization of percolating metal-insulator transition in V_(2)O_(3) using scanning microwave impedance microscopy

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作者： Yi Yang Sixin Wang Wei Xu Kunlun Wei School of Reliability and Systems Engineering Beihang University Department of Electrical and Computer Engineering University of British Columbia

In this paper,a new method of the instantaneous availability（IA） of network system is proposed,combining percolation theory and Markov *** this new method,a network failure is regarded as a percolation process,and the percolation threshold is taken as network system failure *** on percolation theory,IA model of network systems is established using Markov *** Laplace transformation,the analytic solution can be worked out,and one numerical example is given to prove the accurateness of the model comparing with existing ***,the main influencing factors and ways of network IA by numerical simulation are acquired,and there is no fluctuation of the IA under exponential distribution of nodes in network system.

关键词： Instantaneous availability Random network percolation theory Markov process

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Science China(Physics,Mechanics & Astronomy) 2022年第9期65卷 112-118页

作者： Weiyan Lin Huanyu Zhang Yoav Kalcheim Xinchen Zhou Fubao Yang Yang Shi Yang Feng Yihua Wang Jiping Huang Ivan KSchuller Xiaodong Zhou Jian Shen State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200433China Department of Physics Fudan UniversityShanghai 200433China Department of Physics University of California San DiegoLa Jolla 92093USA Center for Advanced Nanoscience University of California San DiegoLa Jolla 92093USA Key Laboratory of Micro and Nano Photonic Structures(MOE) Fudan UniversityShanghai 200433China Beijing Academy of Quantum Information Science Beijing 100193China Shanghai Research Center for Quantum Sciences Shanghai 200433China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China Shanghai Qi Zhi Institute Shanghai 200232China Zhangjiang Fudan International Innovation Center Fudan UniversityShanghai 201203China

Using the extensively studied V_(2)O_(3) as a prototype system, we investigate the role of percolation in metal-insulator transition(MIT). We apply scanning microwave impedance microscopy to directly determine the metallic phase fraction p and relate it to the macroscopic conductance G, which shows a sudden jump when p reaches the percolation threshold. Interestingly, the conductance G exhibits a hysteretic behavior against p, suggesting two different percolating processes upon cooling and warming. Based on our image analysis and model simulation, we ascribe such hysteretic behavior to different domain nucleation and growth processes between cooling and warming, which is likely caused by the decoupled structural and electronic transitions in V_(2)O_(3) during MIT. Our work provides a microscopic view of how the interplay of structural and electronic degrees of freedom affects MIT in strongly correlated systems.

关键词： electronic phase separation metal-insulator transition percolation theory scanning microwave impedance microscopy

Determination of a Pore Structure Parameter of Porous Media by Analysis of percolation Network Model

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Chinese Journal of Chemical Engineering 2000年第4期8卷 287-293页

作者：辛峰王富民廖晖李绍芬天津大学化工学院天津

According to the simulation of nitrogen sorption process in porous media with three-dimensional network model, and the analysis for such a process with percolation theory, a new method is proposed to determine a pore structure parameter--mean coordination number of pore network, which represents the connectivity among a great number of pores. Here the 'chamber-throat' model and the Weibull distribution are used to describe the pore geometry and the pore size distribution respectively. This method is based on the scaling law of percolation theory after both effects of sorption thermodynamics and pore size on the sorption hysteresis loops are considered. The results show that it is an effective procedure to calculate the mean coordination number for micro- and meso-porous media.

关键词： coordination number porous media percolation theory network model sorption

Effect of mechanical ball milling on the electrical and powder bed properties of gas-atomized Ti-48Al-2Cr-2Nb and elucidation of the smoke mechanism in the powder bed fusion electron b eam melting process

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Journal of Materials Science & Technology 2023年第6期137卷 36-55页

作者： Seungkyun Yim Kenta Aoyagi Keiji Yanagihara Huakang Bian Akihiko Chiba Institute for Materials Research Tohoku University2-1-1 KatahiraSendaiMiyagi 980-8577Japan

Smoke is unexpected powder-splashing caused by electrostatic force and is one of the main problems hindering the process stability and applicability of the powder bed fusion electron beam(PBF-EB)*** this study,mechanical stimulation was suggested to suppress smoke of gas-atomized(GA)Ti-48Al-2Cr-2Nb powder using Al_(2)O_(3) and WC ball *** deformation mechanism of the GA powder depending on the ball milling media was discussed based on the developed particle morphology distribu-tion map and contact mechanics *** was revealed that the rapid decrement of flowability and packing density after WC ball milling owing to the formation of angular fragments by the brittle *** variation of surface and electrical properties by mechanical stimulation was investigated via XPS,TEM,and Impedance *** electrical resistivity of the ball-milled powders gradually decreased with increasing milling duration,despite the increased oxide film thickness,and the capacitive response disappeared in Al-60 and WC-30 via metal-insulator *** could be due to the accumulation of strain and defects on the oxide film via mechanical *** smoke mechanism of ball-milled powders was discussed based on the percolation *** the smoke experiment,smoke was more suppressed for WC-10 and WC-20 than that for Al-40 and Al-50,respectively,despite the longer charge dissipation *** could be due to the high probability of contact with conductive *** the Al-60 and WC-30 powders,smoke was further restricted by the formation of a percolation cluster with metal-like electrical *** believe that this study will contribute to a better understanding of the smoke mechanism and process optimization of the PBF-EB.

关键词： Metal-insulator transition Electron beam melting additive manufacturing Packing density Flowability Smoke mechanism percolation theory

Analytical model for the sealant performance of tunnel gasketed joints based on multi-scale contact and percolation theories

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Underground Space 2024年第1期14卷 319-337页

作者： Jiachong Xie Xin Huang Guolong Jin Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Geotechnical and Underground Engineering Ministry of EducationShanghai 200092China College of Civil Engineering&Architecture Xinjiang UniversityUrumqi 830047China China Shipbuilding NDRI Engineering Co. Ltd.Shanghai 200063China

The localised leakage in shield tunnels that mainly occurs at segment joints may induce other defects,which threatens operational *** obtain a universal solution for the sealant performance of gasketed joints,we proposed a novel analytical model based on the multiscale contact and percolation theories,in which the obtained percolation pressure and interfacial separation can be utilized to derive the critical water leakage pressure and leakage *** evolutionary process of leakage was divided into three stages(i.e.,the percolation,leakage and breakdown),which explicitly reveal the progressive hydraulic deterioration of gasketed *** gaskets still own partial waterproof capacity until the end of the leakage stage due to the remaining contact pressure at surface *** proposed model was first verified by several sets of experimental data,based on which the determination of three key model parameters(i.e.,self-sealing slope,sealing coefficient,and expel pressure)were discussed in *** parametric study indicates that the waterproof capacity is significantly affected by the joint opening,offset,and the surface roughness of the *** variation in waterproof capacity with joint opening is mainly due to the nonlinearity of the gasket’s modulus and self-sealing *** increase in joint offset can result in a lower waterproof capacity as well as a larger leakage ***’s surface roughness affects the percolation pressure and interfacial separation,which contributes to the long-term sealant performance.

关键词： Shield tunnel Gasketed joint Sealant performance Hydraulic deterioration percolation theory Surface roughness Leakage rate

Leveraging data fusion to improve barrier coverage in wireless sensor networks

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The Journal of China Universities of Posts and Telecommunications 2013年第1期20卷 26-36,53页

作者： ZHANG Zhao-liang LI Dong HUANG Ting-pei CUI Li Institute of Computing Technology Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences

Intruder detection and border surveillance are amongst the most promising applications of wireless sensor networks. Barrier coverage formulates these problems as constructing barriers in a long-thin region to detect intruders that cross the region. Existing studies on this topic are not only based on simplistic binary sensing model but also neglect the collaboration employed in many systems. In this paper, we propose a solution which exploits the collaboration of sensors to improve the performance of barrier coverage under probabilistic sensing model. First, the network width requirement, the sensor density and the number of barriers are derived under data fusion model when sensors are randomly distributed. Then, we present an efficient algorithm to construct barriers with a small number of sensors. The theoretical comparison shows that our solution can greatly improve barrier coverage via collaboration of sensors. We also conduct extensive simulations to demonstrate the effectiveness of our solution.

关键词： wireless sensor networks coverage deployment data fusion percolation theory

Temperature- and voltage-dependent trap generation model in high-k metal gate MOS device with percolation simulation

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Chinese Physics B 2016年第8期25卷 352-356页

作者：徐昊杨红王艳蓉王文武罗维春祁路伟李俊峰赵超陈大鹏叶甜春 Key Laboratory of Microelectronics Devices & Integrated Technology Institute of Micro ElectronicsChinese Academy of Sciences

High-k metal gate stacks are being used to suppress the gate leakage due to tunneling for sub-45 nm technology *** reliability of thin dielectric films becomes a limitation to device manufacturing,especially to the breakdown *** this work,a breakdown simulator based on a percolation model and the kinetic Monte Carlo method is set up,and the intrinsic relation between time to breakdown and trap generation rate R is studied by TDDB *** is found that all degradation factors,such as trap generation rate time exponent m,Weibull slope β and percolation factor s,each could be expressed as a function of trap density time exponent α.Based on the percolation relation and power law lifetime projection,a temperature related trap generation model is *** validity of this model is confirmed by comparing with experiment *** other device and material conditions,the percolation relation provides a new way to study the relationship between trap generation and lifetime projection.

关键词： high-k metal gate TDDB percolation theory kinetic Monte Carlo trap generation model

Modern methods of underground hydromechanics with applications to reservoir engineering

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Journal of Hydrodynamics 2016年第6期28卷 937-946页

作者： Hua XIANG Valery V.KADET Department of Petroleum and Underground Hydromechanics Gubkin Russian State University of Oil and Gas

In the report the basic principles of new approach to the study of transport processes in porous medium are represented. The ＂percolation＂ approach has arisen as an attempt to overcome the traditional phenomenological approach in the underground hydromechanics, based on the assumption of continuity of saturated porous media, which does not allow to explain and to model a number of effects arising from the fluids flow in porous media. The results obtained are very interesting not only from the scientific point of view but as the scientific basis for a number of enhanced oil recovery technologies.

关键词： fluid flow in porous media percolation theory relative phase permeability oil field development low salinity waterflooding

Performance Analysis of Wireless Network Coding via percolation

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Chinese Journal of Electronics 2014年第1期23卷 179-185页

作者： SHANG Tao FAN Yong WANG Chao LIU Jianwei College of Electronic and Information Engineering Beihang University

In order to investigate the effect of network connectivity on the performance of wireless network coding, we introduce percolation theory to construct the system model of multi-hop wireless network for asymptotic connectivity. Concretely, we proposed a normalization algorithm for random network to layer the nodes of the largest connected component in multi-hop wireless network, and derived the theoretical conditions of percolation occurrence for the normalized hierarchical network of the largest connected component. Furthermore, according to the critical threshold of percolation phenomenon,we derived the performance of wireless network coding for the largest connected component. The mean delay and throughput were quantified in terms of network coding parameters such as coding window size, transmission radius, and node density. These conclusions clarify the effective performance of wireless network coding for random network, and will contribute to the evaluation of optimal performance of wireless network coding.

关键词： Network coding percolation theory Random network Connectivity Node density