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Dynamic Cluster Head for Lifetime Efficiency in WSN

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International Journal of Automation and computing 2009年第1期6卷 48-54页

作者： Hesham Abusaimeh Department of Computer Science Loughborough University Loughborough

Saving energy and increasing network lifetime are significant challenges in wireless sensor networks （WSNs）. In this paper, we propose a mechanism to distribute the responsibility of cluster-heads among the wireless sensor nodes in the same cluster based on the ZigBee standard, which is the latest WSN standard. ZigBee supports ad hoc on-demand vector （AODV） and cluster-tree routing protocols in its routing layer. However, none of these protocols considers the energy level of the nodes in the network establishing process or in the data routing process. The cluster-tree routing protocol supports single or multi-cluster networks. However, each single cluster in the multi-cluster network has only one node acting as a cluster head. These cluster-heads are fixed in each cluster during the network lifetime. Consequently, using these cluster-heads will cause them to die quickly, and the entire linked nodes to these cluster-heads will be disconnected from the main network. Therefore, the proposed technique to distribute the role of the cluster head among the wireless sensor nodes in the same cluster is vital to increase the lifetime of the network. Our proposed technique is better in terms of performance than the original structure of these protocols. It has increased the lifetime of the wireless sensor nodes, and increased the lifetime of the WSN by around 50% of the original network lifetime.

关键词： Cluster-tree routing protocol cluster head energy consumption ad hoc on-demand distance vector (AODV) networklifetime wireless sensor networks (WSNs).

Recursive Filter with Partial Knowledge on Inputs and Outputs

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International Journal of Automation and computing 2015年第1期12卷 35-42页

作者： Jinya Su Baibing Li Wen-Hua Chen Department of Aeronautical and Automotive Engineering Loughborough University School of Business and Economics Loughborough University

This paper investigates the problem of state estimation for discrete-time stochastic linear systems, where additional knowledge on the unknown inputs is available at an aggregate level and the knowledge on the missing measurements can be described by a known stochastic distribution. Firstly, the available knowledge on the unknown inputs and the state equation is used to form the prior distribution of the state vector at each time step. Secondly, to obtain an analytically tractable likelihood function, the effect of missing measurements is broken down into a systematic part and a random part, and the latter is modeled as part of the observation noise. Then, a recursive filter is obtained based on Bayesian inference. Finally, a numerical example is provided to evaluate the performance of the proposed methods.

关键词： Bayesian inference Kalman filter missing measurements state estimation unknown inputs

Robust Assignment of Airport Gates with Operational Safety Constraints

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International Journal of Automation and computing 2016年第1期13卷 31-41页

作者： Shuo Liu Wen-Hua Chen Jiyin Liu Department of Aeronautical and Automotive Engineering Loughborough University School of Business and Economics Loughborough University

This paper reviews existing approaches to the airport gate assignment problem （AGAP） and presents an optimization model for the problem considering operational safety constraints. The main objective is to minimize the dispersion of gate idle time periods （to get robust optimization） while ensuring appropriate matching between the size of each aircraft and its assigned gate type and avoiding the potential hazard caused by gate apron operational conflict. Genetic algorithm is adopted to solve the problem, An illustrative example is given to show the effectiveness and efficiency of the algorithm. The algorithm performance is further demonstrated using data of a terminal from Beijing Capital International Airport （PEK）.

关键词： Gate assignment problem operational safety constraints robust optimization conflict avoidance genetic algorithm.

Preparation of microparticles and nanoparticles using membrane-assisted dispersion,micromixing,and evaporation processes

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Particuology 2024年第1期84卷 30-44页

作者： Goran T.Vladisavljevic Chemical Engineering Department Loughborough UniversityLoughboroughLeicestershire LE113TUUnited Kingdom

Synthetic microporous membranes are increasingly used for energy-efficient and controlled production of micro-and nanoparticles and micro-and nanoemulsions with tuneable morphology and physico-chemical properties through various micromixing,emulsification,and evaporation *** emul-sification processes,the membrane pores are used for dispersed phase injection and size-controlled generation of droplets and droplet-templated *** micromixing processes,membrane is utilised as a micromixer for mixing two miscible liquids,usually solvent and antisolvent-rich solutions,which leads to the creation of supersaturation and subsequent nanoprecipitation or *** mem-brane evaporation processes,membrane is used to prevent phase dispersion while allowing efficient molecular diffusion of solvent and/or antisolvent vapour through gas-filled *** dispersion processes can be operated continuously by decoupling shear stress on the membrane surface from cross flow using tube insets,flow pulsations,swirling flow,membrane oscillations or membrane *** generation and solidification can be performed continuously in a single pass by connecting membrane module with a downstream *** dispersion processes can be used for pro-duction of nanoparticles such as nanovesicles(liposomes,micelles,ethosomes,and niosomes),nanogels,polymeric,lipid and metallic nanoparticles,and *** main advantages of membrane-assisted particle generation are in low energy consumption,controlled geometry and hydrodynamic conditions at the microscale level,flexible throughput due to modular and scalable design of membrane devices,and a wide choice of available microporous membranes with various wall porosities,wetta-bilities,pore sizes,and pore morphologies to suit different applications.

关键词： Nanoparticles Microparticles Nanoemulsions Microemulsions Microporous membrane Crystallisation Flash nanoprecipitation Emulsification Zero liquid discharge

Turbulence modelling of the aerodynamic interaction ofOGV wakes and diffuser flow

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航空动力学报 2011年第10期26卷 2302-2312页

作者： Page Gary McGuirk Jim Department of Aeronautical and Automotive Engineering Loughborough University

Different turbulence closures were used to predict the flow interaction between the wakes created by compressor outlet guide vanes(OGVs) and a downstream annular *** statistical turbulence models were tested based on the classical Reynolds-averaged Navier-Stokes(RANS) *** high-Re and low-Re(Launder-Sharma) versions of the k-ε model were applied to a selected test problem for OGV wake/diffuser *** test problem was specifically chosen because experimentally determined inlet conditions and both profile and performance data were available to validate predictions.A preliminary study was also reported of the more advanced large eddy simulation(LES) *** LES sub-grid-scale(SGS) model was the basic Smagorinsky eddy viscosity assumption,with a Van-Driest damping function for improved capture of near-wall viscous *** between the two RANS models showed little difference in terms of velocity contours at OGV trailing edge and diffuser *** terms of overall diffuser performance(static pressure recovery and total pressure loss coefficients),the high-Re model was shown to agree well with experimental *** preliminary LES study indicates the highly unsteady character of the OGV wake flow,but requires improved treatment of inlet conditions.

关键词： outlet guide vane(OGV) wakes diffuser flow interaction Reynolds-averaged Navier-Stokes(RANS) modelling large eddy simulation(LES) modelling

Flexible Strip Supercapacitors for Future Energy Storage

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International Journal of Automation and computing 2015年第1期12卷 43-49页

作者： Rui-Rong Zhang Yan-Meng Xu David Harrison John Fyson Fu-Lian Qiu Darren Southee College of Engineering Design and Physical Sciences Brunel University London loughborough Design School Loughborough University

Flexible strip supercapacitors are developed and their electrochemical properties are characterized. Activated carbon is used as the electrode material and it is found to have a good porous structure which provides a large surface area for energy ***, this activated carbon performs well. The manufacturing processes for the supercapacitors are described in detail and the preparation process has good reproducibility. The strip supercapacitors are combined in series and parallel to measure their electrical properties. The performances of these two samples in series or in parallel both follow the theoretical models. The electrochemical potential window of a series circuit of these two strip supercapacitors is 4.8 V. The energy and power of the series or parallel circuits are equal to the sums of the two strip supercapacitors.

关键词： Strip supercapacitors activated carbon flexible energy storage characterisation

Adaptive fuzzy tracking control for a class of uncertain MIMO nonlinear systems using disturbance observer

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Science China(Information Sciences) 2014年第1期57卷 246-258页

作者： CHEN Mou CHEN WenHua WU QinXian College of Automation Engineering Nanjing University of Aeronautics and Astronautics Department of Aeronautical and Automotive Engineering Loughborough University Loughborough

In this paper,the adaptive fuzzy tracking control is proposed for a class of multi-input and multioutput(MIMO)nonlinear systems in the presence of system uncertainties,unknown non-symmetric input saturation and external *** logic systems(FLS)are used to approximate the system uncertainty of MIMO nonlinear ***,the compound disturbance containing the approximation error and the timevarying external disturbance that cannot be directly measured are estimated via a disturbance *** appropriately choosing the gain matrix,the disturbance observer can approximate the compound disturbance well and the estimate error converges to a compact *** control strategy is further extended to develop adaptive fuzzy tracking control for MIMO nonlinear systems by coping with practical issues in engineering applications,in particular unknown non-symmetric input saturation and control *** this setting,the disturbance observer technique is combined with the FLS approximation technique to compensate for the efects of unknown input saturation and control *** approach based analysis shows that semi-global uniform boundedness of the closed-loop signals is guaranteed under the proposed tracking control *** simulation results are presented to illustrate the efectiveness of the proposed tracking control schemes.

关键词： MIMO nonlinear system input saturation disturbance observer fuzzy logic systems tracking control

Investigation of wake-induced vibration interference between two staggered wave-cone cylinders at subcritical Reynolds number

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Journal of Hydrodynamics 2024年第2期36卷 378-393页

作者： Lin Zou Di-wei Liu Jian Liu Hong-cheng Zuo Yin-huan Zheng Hao Xia School of Mechanical and Electronic Engineering Wuhan University of TechnologyWuhan430070China Department of Aeronautical and Automotive Engineering Loughborough UniversityLoughboroughUK

The wake induced vibration(WIV)of a one-and two-degree-of-freedom(1DOF,2DOF)downstream wave-cone cylinder(WCC)behind a stationary equal-size upstream wave-cone cylinder in the staggered arrangement is numerically investigated at subcritical Reynolds number of 3900 by using shear stressed transfer(SST)k-ωturbulence *** streamwise pitch ratios(P/Dm)vary from 4 to 6 with a fixed incident angleα=8°.Experimental measurements were also performed for the validation of the present numerical *** is found that the largest vibration amplitude in crossflow direction occurred at P/Dm=4,Ur=8 with small difference of streamwise vibration at P/Dm=4,*** from single wavy-cone cylinder(SWCC),the downstream flexible one of a pair staggered WCCs got larger vibration amplitude during phase switching stage instead of in-phase *** upstream wake will suppress the triple frequency of main frequency in the power spectra density(PSD)functions of Cl but stimulate the double one of *** intriguing vibration mechanism happened in all 2DOF cases where the trajectory of downstream WCC is a significant ellipse rather than a figure of *** transformation of phase switching and the variation of the main frequency of drag coefficient(Cd)can be explained by the vortex-shedding modes of downstream WCC.

关键词： Two wave-cone cylinders staggered arrangement wake induced vibration phase switching vortex shedding

Mechanical behavior of advanced nano-laminates embedded with carbon nanotubes-a review

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International Journal of Smart and Nano Materials 2010年第2期1卷 136-171页

作者： G.Zhou G.Xie X.Bao Department of Aeronautical and Automotive Engineering Loughborough UniversityLoughboroughLE113TUUK Department of Materials Loughborough UniversityLoughboroughLE113TUUK

Embedding carbon nanotubes(CNTs)in load-bearing composite laminate hosts to turn them into nano-laminates is a rapidly emerging field and has tremendous potential in enhancing the mechanical performance of the host *** state-of-the-art review intends to provide a physical insight into the understanding of the enhancing mechanisms of the processed and controlled CNTs in the *** focuses on four aspects:(1)physical characteristics of CNTs,including CNT length,diameter,weight percentage and surface functionalization;(2)processing and control techniques of CNTs in the fabrication of nano-laminates,including distribution,dispersion and orientation controls of CNTs;(3)mechanical properties along with their testing methods,including tension,in-plane compression,in-plane and interlaminar shear(ILS),flexure,mode I and mode II fracture toughness as well as compression-after-impact(CAI),ballistic protection and fatigue;and(4)CNT-matrix load transfer and enhancing mechanisms along with a few major governing *** selective and uniform production of CNTs with specific dimensions and physical properties has yet to be achieved on a consistent ***,the processing details of CNTs vary very significantly among different researchers so that the processed CNTs share little common *** is little control over the CNT orientations in most fabrication processes of the nano-laminates except for some cases associated with chemical vapor deposition(CVD).There are only two reports on in-plane compression and there is only one on in-plane *** reinforcement-dominated mechanical properties such as longitudinal tension and flexure,there was little enhancement ***,the substantial enhancement in in-plane compression strength was also *** matrix-dominated mechanical properties,such as transverse tension,in-plane shear,ILS strength and mode I and mode II fracture toughness,a significant enhancement,albeit with substan

关键词： carbon nanotube(CNT) nano-laminate mechanical properties