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Journal of Integrative Agriculture 2018年第8期17卷 1888-1899页

作者： SONG Chun-xiao Les oxley MA Heng-yun College of Economics and Management Henan Agricultural University Department of Economics and Finance University of Waikato

Water availability is a major constraint on grain production in China, therefore, improving irrigation efficiency is particularly important when agriculture faces extreme weather events. This paper first calculates irrigation efficiency with a translog stochastic frontier production function and then investigates what happens when extreme weather events occur via a Tobit model. The estimated results reveal several important features of irrigation practices: i) irrigation efficiency is lower when extreme weather events occur; ii) large variations in irrigation efficiency occur across irrigation facilities; iii) the farm plots exhibit an extreme distribution across efficiency levels; and iv) water-saving techniques, technology adoption, and the maintenance of farmers’ economic resilience are major determinants of irrigation efficiency. Based on these results we propose the following recommendations: i) farmers should balance crop yield and water use; undertake relevant training programs and adopt water-saving techniques; ii) local governments and researchers should help farmers to find the optimal level of irrigation water use based on their own circumstances and provide better water-saving techniques and training programs rather than simply encouraging farmers to invest in irrigation facilities in the most extreme weather years; and iii) the income level of farm households should be increased so as to improve their resilience to natural disasters.

关键词： irrigation efficiency determinants irrigation facilities water-saving techniques extreme weather events

Do farmers care about climate change? Evidence from five major grain producing areas of China

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Journal of Integrative Agriculture 2019年第6期18卷 1402-1414页

作者： SONG Chun-xiao LIU Rui-feng Les oxley MA Heng-yun College of Economics and Management Henan Agricultural UniversityZhengzhou 450002P.R.China Department of Economics and Finance University of WaikatoHamilton 3240New Zealand

Using a logistic model,this paper empirically investigated farmers’perception of climate change and its determinants based on a field survey of 1 350 rural households across five major grain producing provinces in *** results show:i)There is an apparent difference in perception levels for long-term temperature and precipitation ***,57.4%of farmers perceived the long-term temperature change correctly,but only 29.7%of farmers perceived the long-term precipitation change correctly;ii)The factors influencing the farmers’perceptions are almost completely different between precipitation and temperature,the former are mostly agriculture related,while latter are mostly non-agriculture related,except for farm size;and iii)Farmers are not expected to pay more attention to long-term precipitation changes over the crop growing seasons,because less than 30%of farmers can correctly perceive long-term precipitation ***,to improve the accuracy of farmers’perceptions of climate change,the government is recommended to:i)enhance education and training programs;ii)speed up land transfer and expand household land farm size;iii)develop farmer cooperative organizations;iv)invest more in agricultural infrastructure,specifically in major grain producing regions;and v)improve the agricultural environment and increase farming income.

关键词： China major grain producing areas determinants climate change perception irrigation areas

Automated bolting and meshing on a continuous miner for roadway development

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International Journal of Mining Science and Technology 2013年第1期23卷 55-61页

作者： van Duin Stephen Meers Luke Donnelly Peter oxley Ian University of Wollongong Northfields Avenue Gwynneville NSW Australia

Automated installation of primary roof support material can potentially increase productivity and operator safety in the roadway development process within underground coal mining. Although the broader manufacturing sector has benefited from automation, several challenges exist within the Australian underground coal industry which makes it difficult to fully exploit these technologies. At the University of Wollongong a series of reprogrammable electromechanical manipulators have been designed to overcome these challenges and automatically handle the installation of roof and rib containment consumables on a continuous miner. The automated manipulation removes personnel from hazards in the immediate face area, particularly those associated with working in a confined and unstable working environment in close proximity to rotating and moving equipment. In a series of above ground trials the automated system was successfully demonstrated without human intervention and proven to be capable of achieving cycle times at a rate of 10 m per operating hour, consistent with that required to support high capacity longwall mines. The trials also identified a number of refinements which could further improve both cycle times and system reliability when considering the technology for underground use. The results have concluded that conventional manual handling practices on a continuous miner can be eliminated, and that the prototypes have significantly reduced the technical risk in proceeding to a full underground trial.

关键词： Automation Robotics Roadway development Manipulation Roof support

The puzzle of the missing meat: Food away from home and China's meat statistics

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Journal of Integrative Agriculture 2015年第6期14卷 1033-1044页

作者： XIAO Hong-bo CHEN Qiong WANG Ji-min Les oxley MA Heng-yun School of Economics and Management Beijing University of Agriculture Institute of Rural Economy and Agricultural Regional Planning Tianjin Academy of Agricultural Sciences Institute of Agricultural Economics and Development Chinese Academy of Agricultural Sciences Department of Economics University of Waikato College of Economics and Management Henan Agricultural University

From 1985, an increasing gap has emerged between the official statistical measures of meat production and meat consumption in China, which has raised concerns from many researchers using such data. In this paper we report the results of 428 observations（survey of 107 urban and rural households×4 quarters） from 7 provinces conducted in 2010, and compare them with the official statistical data from the National Bureau of Statistics of China（NBSC）. We conclude that the main reason for the discrepancy is due to the underreporting of consumption, which is due mainly to the omission of consumption away from home.

关键词： consumed quarters capita official household income missing puzzle Bureau raised

Probing atomic-scale symmetry breaking by rotationally invariant machine learning of multidimensional electron scattering

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npj Computational Materials 2021年第1期7卷 595-600页

作者： Mark P.oxley Maxim Ziatdinov Ondrej Dyck Andrew R.Lupini Rama Vasudevan Sergei V.Kalinin Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTNUSA Computational Sciences and Engineering Division Oak Ridge National LaboratoryOak RidgeTNUSA

The 4D scanning transmission electron microscopy(STEM)method maps the structure and functionality of solids on the atomic scale,yielding information-rich data sets describing the interatomic electric and magnetic fields,structural and electronic order parameters,and other symmetry breaking distortions.A critical bottleneck is the dearth of analytical tools that can reduce complex 4D-STEM data to physically relevant *** propose an approach for the systematic exploration of 4D-STEM data using rotationally invariant variational autoencoders(rrVAE),which disentangle the general rotation of the object from other latent *** implementation of purely rotational rrVAE is discussed as are applications to simulated data for graphene and zincblende *** rrVAE analysis of experimental 4D-STEM data of defects in graphene is illustrated and compared to the classical center-of-mass *** approach is universal for probing symmetry-breaking phenomena in complex systems and can be implemented for a broad range of diffraction methods.

关键词： symmetry breaking rotational

Deep learning ferroelectric polarization distributions from STEM data via with and without atom finding

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npj Computational Materials 2021年第1期7卷 1342-1352页

作者： Christopher T.Nelson Ayana Ghosh Mark oxley Xiaohang Zhang Maxim Ziatdinov Ichiro Takeuchi Sergei V.Kalinin Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTNUSA Computational Sciences and Engineering Division Oak Ridge National LaboratoryOak RidgeTNUSA Department of Materials Science and Engineering University of MarylandCollege ParkMDUSA

Over the last decade,scanning transmission electron microscopy(STEM)has emerged as a powerful tool for probing atomic structures of complex materials with picometer precision,opening the pathway toward exploring ferroelectric,ferroelastic,and chemical phenomena on the atomic *** to date extracting a polarization signal from lattice coupled distortions in STEM imaging rely on discovery of atomic positions from intensity maxima/minima and subsequent calculation of polarization and other order parameter fields from the atomic ***,we explore the feasibility of polarization mapping directly from the analysis of STEM images using deep convolutional neural networks(DCNNs).In this approach,the DCNN is trained on the labeled part of the image(i.e.,for human labelling),and the trained network is subsequently applied to other *** explore the effects of the choice of the descriptors(centered on atomic columns and grid-based),the effects of observational bias,and whether the network trained on one composition can be applied to a different *** analysis demonstrates the tremendous potential of the DCNN for the analysis of high-resolution STEM imaging and spectral data and highlights the associated limitations.

关键词： Deep network ferroelectric

Manifold learning of four-dimensional scanning transmission electron microscopy

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npj Computational Materials 2019年第1期5卷 1097-1104页

作者： Xin Li Ondrej E.Dyck Mark P.oxley Andrew R.Lupini Leland McInnes John Healy Stephen Jesse Sergei V.Kalinin Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Institute for Functional Imaging of Materials Oak Ridge National LaboratoryOak RidgeTN 37831USA Tutte Institute for Mathematics and Computing OttawaCanada

Four-dimensional scanning transmission electron microscopy(4D-STEM)of local atomic diffraction patterns is emerging as a powerful technique for probing intricate details of atomic structure and atomic electric ***,efficient processing and interpretation of large volumes of data remain challenging,especially for two-dimensional or light materials because the diffraction signal recorded on the pixelated arrays is *** we employ data-driven manifold leaning approaches for straightforward visualization and exploration analysis of 4D-STEM datasets,distilling real-space neighboring effects on atomically resolved deflection patterns from single-layer graphene,with single dopant atoms,as recorded on a pixelated *** extracted patterns relate to both individual atom sites and sublattice structures,effectively discriminating single dopant anomalies via multimode *** believe manifold learning analysis will accelerate physics discoveries coupled between data-rich imaging mechanisms and materials such as ferroelectric,topological spin,and van der Waals heterostructures.

关键词： manifold straight details

Deep Bayesian local crystallography

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npj Computational Materials 2021年第1期7卷 1649-1660页

作者： Sergei V.Kalinin Mark P.oxley Mani Valleti Junjie Zhang Raphael P.Hermann Hong Zheng Wenrui Zhang Gyula Eres Rama K.Vasudevan Maxim Ziatdinov Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Bredesen Center for Interdisciplinary Research The University of TennesseeKnoxvilleTN 37996USA Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Materials Science Division Argonne National LaboratoryArgonneIL 60439USA Computational Sciences and Engineering Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Present address:State Key Laboratory of Crystal Materials&Institute of Crystal Materials Shandong UniversityJinanShandong 250100China

The advent of high-resolution electron and scanning probe microscopy imaging has opened the floodgates for acquiring atomically resolved images of bulk materials,2D materials,and *** plethora of data contains an immense volume of information on materials structures,structural distortions,and physical *** this knowledge regarding local physical phenomena necessitates the development of the mathematical frameworks for extraction of relevant ***,the analysis of atomically resolved images is often based on the adaptation of concepts from macroscopic physics,notably translational and point group symmetries and symmetry lowering ***,we explore the bottom-up definition of structural units and symmetry in atomically resolved data using a Bayesian *** demonstrate the need for a Bayesian definition of symmetry using a simple toy model and demonstrate how this definition can be extended to the experimental data using deep learning networks in a Bayesian setting,namely rotationally invariant variational autoencoders.

关键词： symmetry local resolved

A New Procedure to Test for Fractional Integration

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Open Journal of Statistics 2016年第4期6卷 651-666页

作者： William Rea Chris Price Les oxley Marco Reale Jennifer Brown Department of Economics and Finance University of Canterbury Christchurch New Zealand Department of Mathematics and Statistics University of Canterbury Christchurch New Zealand Waikato Management School University of Waikato Hamilton New Zealand

It is now widely recognized that the statistical property of long memory may be due to reasons other than the data generating process being fractionally integrated. We propose a new procedure aimed at distinguishing between a null hypothesis of unifractal fractionally integrated processes and an alternative hypothesis of other processes which display the long memory property. The procedure is based on a pair of empirical, but consistently defined, statistics namely the number of breaks reported by Atheoretical Regression Trees (ART) and the range of the Empirical Fluctuation Process (EFP) in the CUSUM test. The new procedure establishes through simulation the bivariate distribution of the number of breaks reported by ART with the CUSUM range for simulated fractionally integrated series. This bivariate distribution is then used to empirically construct a test which rejects the null hypothesis for a candidate series if its pair of statistics lies on the periphery of the bivariate distribution determined from simulation under the null. We apply these methods to the realized volatility series of 16 stocks in the Dow Jones Industrial Average and show that the rejection rate of the null is higher than if either statistic was used as a univariate test.

关键词： Long-Range Dependence Strong Dependence Global Dependence Regression Trees CUSUM Test Volatility

Design,characterization and fabrication of an In_(0.53)Ga_(0.47)As planar Gunn diode operating at millimeter waves

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太赫兹科学与电子信息学报 2015年第3期13卷 507-510页

作者： Mohamed Ismaeel Maricar A Khalid D S R Cumming C H oxley School of Engineering and Computing Science University of Durham Microsystem Technology Research Group University of Glasgow Department of Electronics Engineering De Montfort University

This paper describes the design,characterization and fabrication of a planar In0.53Ga0.47As based planar Gunn diode on an In P semi-insulating *** planar Gunn diode was designed in Coplanar Waveguide(CPW)format with an active channel length and width of 4μm and 120μm respectively,and modeled using the Advanced Design System(ADS-2009)simulation *** initial experimental measurements have given a fundamental oscillation frequency of 63.5 GHz with a RF output power of-6.6 d Bm,which is the highest recorded power for an In P based planar Gunn diode.

关键词： indium phosphide planar Gunn devices millimeter-wa