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Wireless Acoustic Sensor Networks and Edge Computing for Rapid Acoustic monitoring

IEEE/CAA Journal of Automatica Sinica 2019年第1期6卷 64-74页

作者： Zhengguo Sheng Saskia Pfersich Alice Eldridge Jianshan zhou Daxin Tian Victor C.m.Leung the Department of Engineering and Design University of Sussex Infineon Technologies AG the Department of music University of Sussex Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC) Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems & Safety ControlSchool of Transportation Science and EngineeringBeihang University the Department of Electrical and Computer Engineering The University of British Columbia

Passive acoustic monitoring is emerging as a promising solution to the urgent, global need for new biodiversity assessment methods. The ecological relevance of the soundscape is increasingly recognised, and the affordability of robust hardware for remote audio recording is stimulating international interest in the potential for acoustic methods for biodiversity *** scale of the data involved requires automated methods,however, the development of acoustic sensor networks capable of sampling the soundscape across time and space and relaying the data to an accessible storage location remains a significant technical challenge, with power management at its core. Recording and transmitting large quantities of audio data is power intensive,hampering long-term deployment in remote, off-grid locations of key ecological interest. Rather than transmitting heavy audio data, in this paper, we propose a low-cost and energy efficient wireless acoustic sensor network integrated with edge computing structure for remote acoustic monitoring and in situ *** and computation of acoustic indices are carried out directly on edge devices built from low noise primo condenser microphones and Teensy microcontrollers, using internal FFT hardware support. Resultant indices are transmitted over a ZigBee-based wireless mesh network to a destination *** tests of audio quality, indices computation and power consumption demonstrate acoustic equivalence and significant power savings over current solutions.

关键词： Acoustic sensor networks edge computing energy efficiency

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modelling and mapping soil erosion potential in China

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Journal of Integrative Agriculture 2019年第2期18卷 251-264页

作者： TEng Hong-fen HU Jie zhou Yue zhou Lian-qing SHI zhou College of Environmental and Resource Sciences Zhejiang UniversityHangzhou 310058P.R.China State Key Laboratory of Soil and Sustainable Agriculture Chinese Academy of SciencesNanjing 210008P.R.China

Soil erosion is an important environmental threat in ***,quantitative estimates of soil erosion in China have rarely been reported in the *** this study,soil loss potential in China was estimated by integrating satellite images,field samples,and ground observations based on the Revised Universal Soil Loss Equation(RUSLE).The rainfall erosivity factor was estimated from merged rainfall data using Collocated CoKriging(ColCOK)and downscaled by geographically weighted regression(GWR).The Random Forest(RF)regression approach was used as a tool for understanding and predicting the relationship between the soil erodibility factor and a set of environment *** results show that the average erosion rate in China is 1.44 t ha^(–1) yr^(–1).more than 60%of the territory in China is influenced by soil erosion limitedly,with an average potential erosion rate less than 0.1 t ha^(–1) yr^(–1).Other unused land and other forested woodlands showed the highest erosion *** estimates are comparable to those of runoff plot *** results provide a useful tool for soil loss assessments and ecological environment protections.

关键词： soil erosion potential RUSLE mapping modelling

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On the Detection of multiple-Access Spatial modulations

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Chinese Journal of Electronics 2017年第1期26卷 172-178页

作者： zhou Enzhi HAO Li Key Lab of Information Coding and Transmission Southwest Jiaotong University

The detection problem for the multipleaccess Spatial modulations(m-Sm) is investigated in this paper, where multiple transmitters adopting spatial modulation communicate to the receiver at the same *** optimal maximum-likelihood(mL) detection suffers from the high computational complexity, while Sphere decoding(SD) can not reduce the complexity effectively because of the multiple active antennas in m-Sm. In order to avoid the high complexity, a Space-alternating generalized expectation-maximization(SAGE) algorithm aided List-pro jection(S-LP) detector is proposed and applied to m-Sm systems. The received signal vector is firstly projected onto the subspaces spanned by the columns of channel matrices corresponding to the possible active antennas. Then some combinations of antenna indices with the largest pro jections are selected as candidate index sets,based on which, a modified SAGE algorithm is applied to update the candidate symbols. Both analysis and simulation results show that the proposed S-LP detector achieves a near-optimum performance with a significantly reduced complexity compared with mL and SD detection.

关键词： multiple-input multiple-output(mImO) Spatial modulation(Sm) multi-user detection

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Arc Erosion Behavior of Cu–0.23Be–0.84Co Alloy after Heat Treatment: An Experimental Study

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Acta metallurgica Sinica(English Letters) 2016年第4期29卷 399-408页

作者： Yanjun zhou Kexing Song Jiandong Xing zhou Li Xiuhua Guo State Key Laboratory for mechanical Behavior of materials School of Materials Science and Engineering Xi’an Jiaotong University Collaborative Innovation Center of Nonferrous metals Henan University of Science and Technology School of materials Science and Engineering Henan University of Science and Technology School of materials Science and Engineering Central South University

The arc erosion behavior of Cu-0.23Be-0.84Co alloy after heat treatment was investigated experimentally by a JF04C electric contact test system. The arc duration, arc energy, contact resistance and contact pressure of Cu-0.23Be- 0.84Co alloy after solution treatment and aging treatment were analyzed. The arc erosion morphologies were contrastively observed by a three-dimensional measuring system and scanning electron microscopy. For the Cu-0.23Be-0.84Co alloy in solution state and aging state, the maximum values of arc duration are 90 and 110 ms, and the arc energies are 15,000 and 18,000 mJ, respectively. The maximum value of the contact resistance of Cu-0.23Be-0.84Co alloy in different states is about 33 mΩ The contact pressure of Cu-0.23Be-0.84Co alloy in solution state generally changes between 50 and 60 cN during whole make-and-break contacts, while in aging state, it has a larger fluctuation range. moreover, the quality of moving contact （anode） decreases, while static contact （cathode） increases. The materials transfer from anode to cathode during make-and-break contacts. The total mass losses of Cu-0.23Be-0.84Co alloy in solution state and aging state are 3 and 1.2 mg, respectively. In addition, a number of discrete corrosion pits, molten droplet, porosity and cavity distribute on the surface of moving contact and static contact. The arc erosion model of Cu-0.23Be-0.84Co alloy in make-and-break contact was built. The arc erosion resistance of Cu-0.23Be-0.84Co alloy after heat treatment is closely related to the microstructure and the properties of contact materials. This experimental study is important to evaluate the anode or cathode electrocorrosion fatigue life.

关键词： Cu-Be-Co alloy Arc erosion Aging morphology

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Control and Stabilization of the Rosenau Equation Posed on a Periodic Domain

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Journal of Systems Science & Complexity 2018年第4期31卷 889-906页

作者： zhou Deqin mU Chunlai College of mathematics and Statistics Chongqing University

This paper considers the Rosenau equation with a moving control δtu＋δtδx4u＋δxu＋uδzu=a（x＋ct）h（x,t）,c≠0,x∈T=R/（2πZ）,t〉0, The authors prove that the Rosenau equation with a moving control is locally exact controllable in H8（T） with s ≥ 0 and globally exponential stable in H8（T） with s ≥2. The two results nontrivially extend the work of （Rosier L and Zhang B Y, 2013） from the BBm equation to the Rosenau equation.

关键词： Exact controllability Rosenau equation stabilization

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Tool Wear and Its Effect on Surface Roughness in Diamond Cutting of Glass Soda-lime

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Chinese Journal of mechanical Engineering 2012年第6期25卷 1224-1230页

作者： JIA Peng zhou m.ng Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China School of mechanical and Electrical Engineering Harbin Institute of Technology Harbin 150001 China

For the technology of diamond cutting of optical glass, the high tool wear rate is a main reason for hindering the practical application of this technology. many researches on diamond tool wear in glass cutting rest on wear phenomenon describing simply without analyzing the genesis of wear phenomenon and interpreting the formation process of tool wear in mechanics. For in depth understanding of the tool wear and its effect on surface roughness in diamond cutting of glass, experiments of diamond turning with cutting distance increasing gradually are carried out on soda-lime glass. The wear morphology of rake face and flank face, the corresponding surface features of workpiece and the surface roughness, and the material compositions of flank wear area are detected. Experimental results indicate that the flank wear is predominant in diamond cutting glass and the flank wear land is characterized by micro-grooves, some smooth crater on the rake face is also seen. The surface roughness begins to increase rapidly, when the cutting mode changes from ductile to brittle for the aggravation of tool wear with the cutting distance over 150 m. The main mechanisms of inducing tool wear in diamond cutting of glass are diffusion, mechanical friction, thermo-chemical action and abrasive wear. The proposed research makes analysis and research from wear mechanism on the tool wear and its effect on surface roughness in diamond cutting of glass, and provides theoretical basis for minimizing the tool wear in diamond cutting brittle materials, such as optical glass.

关键词： diamond cutting tool wear surface roughness soda-lime glass

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Uncertainty in crossing time of 2 °C warm.ng threshold over China

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Science Bulletin 2016年第18期61卷 1451-1459页

作者： Xiaolong Chen Tianjun zhou State Key Laboratory of Numerical modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029 China

The 2 ℃ warm.ng target has been used widely in global and regional climate change research. Previous studies have shown large uncertainties in the time when surface air temperature （SAT） change over China will reach 2℃ rela- tive to the pre-industrial era. To understand the uncertainties, we analyzed the projected SAT in the twenty-first century using 40 state-of-the-art climate models under two Repre- sentative Concentration Pathways （RCP4.5 and RCPS.5） from the Coupled model Intercomparison Project Phase 5. The 2℃ threshold-crossing time （TCT） of SAT averaged across China was around 2033 and 2029 for RCP4.5 and RCP8.5, respectively. Considering a 4-1o- range of inter- model SAT change, the upper and lower bounds of the 2 ℃ TCT could differ by about 25 years or even more. Uncer- tainty in the projected SAT and the warm.ng rate around the TCT are the two main factors responsible for the TCT uncertainty. The former is determined by the climate sensi- tivity represented by the global mean surface temperature response. About 45 % of the intermodel variance of the projected 2 ~C TCT for averaged SAT over China can be explained by climate sensitivity across the models, which is contributed mainly by central and southern China. In a cli- mate more sensitive to CO2 forcing, stronger greenhouse effect, less stratus cloud over the East Asian monsoon region, and less snow cover on the Tibetan Plateau result in increased downward longwave radiation, increased shortwave radia- tion, and decreased shortwave radiation reflected by the surface, respectively, all of which may advance the TCT.

关键词： 2 °C threshold Projection uncertainty China region CmIP5 Climate sensitivity

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modeling and applying credible interval intuitionistic fuzzy reciprocal preference relations in group decision making

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Journal of Systems Engineering and Electronics 2017年第2期28卷 301-314页

作者： Wei zhou Zeshui Xu Business School Sichuan University International Business School Yunnan University of Finance and Economics

Intuitionistic fuzzy preference relations are powerful techniques used to express uncertain preference information. However, simultaneously providing the exact priority and non-priority intensities could be difficult in real applications. A credible interval intuitionistic fuzzy number (CIIFN) is introduced and a credible interval intuitionistic fuzzy reciprocal preference relation (CIIFRPR) is developed to solve this issue. Unlike intuitionistic fuzzy preference relations, the new preference relations use the CIIFNs to express the preference information such that the decision makers simply provide the priority intensity with interval-valued numbers and calculate the non-preference intensity with the transformed method, which avoids a complex evaluation of non-priority information. Furthermore, some basic operations and comparison laws are investigated, based on which three credible interval intuitionistic fuzzy aggregation operators are proposed. Two models are presented to manage the group decision-making. Finally, a practical case is used to demonstrate the feasibility and reasonability of the proposed preference relations and aggregation operators. © 2017 Beijing Institute of Aerospace Information.

关键词： Fuzzy rules Fuzzy sets mathematical operators

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Phase Transformation and Thermal Stability of Aged Ti-Ni-Hf High Temperature Shape memory Alloys

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Journal of materials Science & Technology 2006年第5期22卷 691-695页

作者： Xianglong m.ng Wei CAI K.T.Lau L.m.zhou Liancheng ZHAO School of materials science ＆ Engineering Harbin Institute of Technology Harbin 150001 China Department of mechanical Engineering The Hong Kong Polytechnic umversity Hung Horn KowloonHong Kong China

The use of Ni-rich TiNiHf alloys as high temperature shape memory alloys （SmAs） through aging has been presented. For Ni-rich Ti80-xNixHf20 alloys, their phase transformation temperatures are averagely increased more than 100 K by aging at 823 K for 2 h. Especially for the alloys with Ni-content of 50.4 at. pct and 50.6 at. pct, their martensitic transformation start temperatures （ms） are more than 473 K after aging. TEm observation confirmed that some fine particles precipitate from the matrix during aging. The aged Ni-rich TiNiHf SmAs show the better thermal stability of phase transformation temperatures than the solutiontreated TiNiHf alloys. The fine particles precipitated during aging should be responsible for the increase of phase transformation temperatures and its high stability.

关键词： TiNiHf alloy High temperature shape memory alloy Aging Phase transformation

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High Hole mobility of GaSb Relaxed Epilayer Grown on GaAs Substrate by mOCVD through Interfacial misfit Dislocations Array

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Journal of materials Science & Technology 2012年第2期28卷 132-136页

作者： Wei zhou Xiang Li Sujing Xia Jie Yang Wu Tang K.m.Lau State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Tech- nology of China Chengdu 610054 China Department of Electronic and Computer Engineering Hong Kong University of Science ＆ Technology Hong Kong China

The structural property of GaSb epilayers grown on semi-insulator GaAs （001） substrate by metalorganic chemical vapor deposition （mOCVD） using Triethylgallium （TEGa） and trimethylantimony （TmSb）, was investigated by variation of the Sb：Ga （V/Ill） ratio. An optimum V/Ill ratio of 1.4 was determined in our growth conditions. Using transmission electron microscopy （TEm）, we found that there was an interracial misfit dislocations （ImF） growth mode in our experiment, in which the large misfit strain between epilayer and substrate is relaxed by periodic 90 deg. ImF array at the hetero-epitaxial interface. The rms roughness of a 300 nm-thick GaSb layer is only 2.7 nm in a 10μm×10μm scan from atomic force microscopy （AFm） result. The best hole density and mobility of 300 nm GaSb epilayer are 5.27xi06 cm-3（1.20×106） and 553 cm2-V-l.s-1 （2340） at RT （77 K） from Hall measurement, respectively. These results indicate that the ImF growth mode can be used in mOCVD epitaxial technology similar to molecular beam epitaxy （mBE） technology to produce the thinner GaSb layer with low density of dislocations and other defects on GaAs substrate for the application of devices.

关键词： Interfacial misfit dislocations metalorganic chemical vapour deposition misfit dislocation Hole mobility

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