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Intelligent Wireless Communications Enabled by Cognitive Radio and Machine Learning

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China Communications 2018年第12期15卷 16-48页

作者： Xiangwei Zhou Mingxuan Sun Geoffrey Ye Li Biing-Hwang (fred) Juang School of EECS Louisiana State University School of ECE Georgia Institute of Technology

The ability to intelligently utilize resources to meet the need of growing diversity in services and user behavior marks the future of wireless communication systems. Intelligent wireless communications aims at enabling the system to perceive and assess the available resources, to autonomously learn to adapt to the perceived wireless environment, and to reconfigure its operating mode to maximize the utility of the available resources. The perception capability and reconfigurability are the essential features of cognitive radio while modern machine learning techniques project great potential in system adaptation. In this paper, we discuss the development of the cognitive radio technology and machine learning techniques and emphasize their roles in improving spectrum and energy utility of wireless communication systems. We describe the state-of-the-art of relevant techniques, covering spectrum sensing and access approaches and powerful machine learning algorithms that enable spectrum and energy-efficient communications in dynamic wireless environments. We also present practical applications of these techniques and identify further research challenges in cognitive radio and machine learning as applied to the existing and future wireless communication systems.

关键词： cognitive radio energy efficiency machine learning reconfiguration spectrum efficiency

Modelling and simulating Chikungunya spread with an unstructured triangular cellular automata

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Infectious Disease Modelling 2020年第1期5卷 197-220页

作者： Gerardo Ortigoza fred Brauer Iris Neri Facultad de Ingeniería Universidad VeracruzanaBoca Del RíoVerMexico Mathematics Department University of British ColumbiaVancouverB.CCanada Maestría en Gestion Integrada de Cuencas Universidad Autonoma de QueretaroMexico

In this work we propose a mathematical model to simulate Chikungunya spread;the spread model is implemented in a C++ cellular automata code defined on unstructured triangular grids and space visualizations are performed with *** order to simulate the time space spread of the Chikungunya diseases we include assumptions such as:heterogeneous human and vector densities,population mobility,geographically localized points of infection using geographical information systems,changes in the probabilities of infection,extrinsic incubation and mosquito death rate due to environmental *** experiments reproduce the qualitative behavior of diseases spread and provide an insight to develop strategies to prevent the diseases spread.

关键词： Cellular automata Unstructured triangular grids Chikungunya spread

Modular Design Method for Motor Drives

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Chinese Journal of Electrical Engineering 2018年第1期4卷 1-10页

作者： Dong Jiang Puqi Ning Rixin Lai Zhihao Fang fred Wang State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China Institute of Electrical Engineering Chinese Academy of ScienceBeijing 100083China HITTOP Investment Management CO.LTD Beijing 100020China University of Tennessee KnoxvilleUSA

This paper introduces the concept of modular design methodology for hardware design and development of motor *** modular design process is first introduced separating the hardware development into three parts:controller,mother board and phase-leg *** control and circuit function can be decoupled from the phase-leg module *** hardware update can be simplified with the phase-leg module development and *** design examples are used to demonstrate this method:a DC-fed motor drive with Si IGBTs and an AC-fed motor drive with SiC *** of DC-fed motor drive aims at developing the converter with customized IGBT package for high *** with development of the converter with commercial IGBTs simplifies the *** the AC-fed motor drive is a more complex topology using more advanced devices,the modular design method can simplify and improve the development especially for new packaged ***,the modular design method can help to study the electromagnetic interference(EMI)issue for motor drives,which is presented with an extra design example.

关键词： Motor drive devices modular gate driver

EVOLUTIONARY CHARACTERISTICS OF LAKES AND PALAEOCLIMATIC UNDULATION IN THE Q AID AM BASIN,CHINA

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Chinese Journal of Oceanology and Limnology 1993年第1期11卷 34-45页

作者：黄麒 Teh-Lung Ku fred M.Phillips Institute of Salt Lakes Academia Sinica Xining 810008 Department of Geological Sciences University of Southern California Los Angeles CA. 90089-0740 U.S.A. Geoscience Department New Mexico Institute of Mining and Technology Socorro NM 87801 U.S.A

The Qaidam Basin is. a tectonically controlled depression at 2700 m altitude on the northern margin of the Tibet Plateau. A succession of Neogene clastic sediments indicates lake depocentre migration from NW to SE. Towards late Pliocene, evaporative conditions developed with formation of gypsum, halite, celestite, mirabilite and bloedite. Continued deformation through Pleistocene developed a series of NW- SE trending domes and troughs. This setting continued to exert a controlling influence on basin and brine evolution and the progressive development of sulfate to chloride brines as, dry conditions intensified in late Pleistocene, at the end of which, extensive flat floors were formed in Dalangtan, Qarhan and other ***, model, which was set up based on the synthetic analyses, divides the fluctuating palaeoclimate since 750ka,B. P. into 11 warm and humid stages and 10 dry and cold stages. The water of the lakes evaporated during the dry-cold periods and were freshened during the warm-humid

关键词： evolution of salt lakes organic carbon stratigraphy undulating model of paleoclimate

Representation of Infinite-Dimensional Forward Price Models in Commodity Markets

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Communications in Mathematics and Statistics 2014年第1期2卷 47-106页

作者： fred Espen Benth Paul Krühner Centre of Mathematics for Applications University of OsloP.O.Box 1053Blindern0316 OsloNorway Department of Mathematics University of OsloP.O.Box 1053Blindern0316 OsloNorway

We study the forward price dynamics in commodity markets realised as a process with values in a Hilbert space of absolutely continuous functions defined by Filipovi´c(Consistency problems for Heath–Jarrow–Morton interest rate models,2001).The forward dynamics are defined as the mild solution of a certain stochastic partial differential equation driven by an infinite-dimensional Lévy *** is shown that the associated spot price dynamics can be expressed as a sum of Ornstein–Uhlenbeck processes,or more generally,as a sum of certain stationary *** results link the possibly infinite-dimensional forward dynamics to classical commodity spot *** continue with a detailed analysis of multiplication and integral operators on the Hilbert spaces and show that Hilbert–Schmidt operators are essentially integral *** covariance operator of the Lévy process driving the forward dynamics and the diffusion term can both be specified in terms of such operators,and we analyse in several examples the consequences on model dynamics and their probabilistic ***,we represent the forward price for contracts delivering over a period in terms of an integral operator,a case being relevant for power and gas *** several examples,we reduce our general model to existing commodity spot and forward dynamics.

关键词： Forward price Infinite-dimensional stochastic processes Lévy processes Commodity markets Heath–Jarrow–Morton approach

An AlGaN/GaN HEMT with a reduced surface electric field and an improved breakdown voltage

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Chinese Physics B 2012年第8期21卷 360-364页

作者：谢刚 Edward Xu Niloufar Hashemi 张波 fred Y.Fu Wai Tung Ng The Edward S.Rogers Sr.Electrical and Computer Engineering Department University of Toronto State key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Crosslight Software Inc.Burnaby BCCanada

A reduced surface electric field in an AlGaN/GaN high electron mobility transistor （HEMT） is investigated by employing a localized Mg-doped layer under the two-dimensional electron gas （2-DEG） channel as an electric field shaping layer. The electric field strength around the gate edge is effectively relieved and the surface electric field is distributed evenly as compared with those of HEMTs with conventional source-connected field plate and double field plate structures with the same device physical dimensions. Compared with the HEMTs with conventional sourceconnected field plates and double field plates, the HEMT with a Mg-doped layer also shows that the breakdown location shifts from the surface of the gate edge to the bulk Mg-doped layer edge. By optimizing both the length of Mg-doped layer, Lm, and the doping concentration, a 5.5 times and 3 times the reduction in the peak electric field near the drain side gate edge is observed as compared with those of the HEMTs with source-connected field plate structure and double field plate structure, respectively. In a device with VGS = -5 V, Lm 1.5 m, a peak Mg doping concentration of 8×10^17 cm-3 and a drift region length of 10 m, the breakdown voltage is observed to increase from 560 V in a conventional device without field plate structure to over 900 V without any area overhead penalty.

关键词： AlGaN/GaN HEMT reduced surface electric field Mg-doped layer breakdown voltage

Converter-Based Reconfigurable Real-Time Electrical System Emulation Platform

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Chinese Journal of Electrical Engineering 2018年第1期4卷 20-27页

作者： Yiwei Ma Jingxin Wang fred Wang Leon M.Tolbert CURENT The University of TennesseeKnoxvilleTN 37996USA Oak Ridge National Laboratory Oak RidgeTN 37831USA

A Hardware Testbed(HTB)is developed for accurate and flexible emulation and testing of electrical power system and their control,measurement,and protection *** the HTB,modular and programmable power electronics converters are used to mimic the static and dynamic characteristics of electrical power *** paper overviews the development,integration,and application of the HTB,covering emulation principle,hardware and software configuration,and example results of power system research using the *** advantages of the HTB,compared with real-time digital simulation and downscaled hardware-based testing platform are discussed.

关键词： Emulation modeling real-time simulation

Anthropometric and Physical Performance Profiles of High School Age American Football Players: 11th and 12th Grade Japanese Athletes

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Journal of Science in Sport and Exercise 2023年第1期5卷 25-33页

作者： Daichi Yamashita Shota Yamaguchi fred Ariel Hernandez Yasuhiro Yuasa Depart of Sports Science Japan Institute of Sports Sciences3-15-1NishigaokaKita-kuTokyo 115-0056Japan Institute of Physical Education Keio University4-1-1HiyoshiKanagawa 223-8521Japan Department of Anthropology University of California-Irvine3203 Social&Behavioral Sciences GatewayIrvineCalifornia 92697-5100USA Faculty of Sports and Health Science Department of Sports Science Daito Bunka University1-9-1 TakashimadairaItabashi-kuTokyo 175-8571Japan

Purpose To compare anthropometric and physical performance profiles of Japanese 11th and 12th grade American football players within each positional *** Fifty-two 11th and 12th grade American football players from two Japanese high schools participated in the study during the summer pre-season *** performed anthropometric(height and body mass)and physical(vertical jump,broad jump,40-yard dash,pro-agility shuttle 4-kg medicine ball chest throw,front throw,and back throw)*** jump momentum and 10-yard sprint momentum were also calculated by multiplying the velocity and body *** were divided into two groups by playing positions:skill players and *** Skill players in the 12th grade were better at medicine ball chest throw(d=0.73,P=0.04)and vertical jump momen-tum(d=0.75,P=0.03)than those in the 11th ***,there were no differences in any measurements(P>0.05)between linemen from the two *** The current study suggests that upper and lower body absolute power and momentum production can be improved for skill players even over 17 years *** the other hand,body size and speed,attributes that did not change between 11th and 12th grades,seem to be essential talent identification criteria in the current *** study is needed to monitor longitudinal performance improvements in implementing talent development programs by focusing on the quality of speed,agility and power development at the youth level.

关键词： Cross-sectional study Physical fitness profile Talent identification Talent development Long-term athletic development

Hlder Norm Estimate for a Hilbert Transform in Hermitean Clifford Analysis

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Acta Mathematica Sinica,English Series 2012年第11期28卷 2289-2300页

作者： Ricardo ABREU-BLAYA Juan BORY-REYES fred BRACKX Hennie DE SCHEPPER Frank SOMMEN Facultad de Informática y Matemática Universidad de Holguín Departamento de Matemática Universidad de Oriente Clifford Research Group Faculty of Engineering Ghent University Clifford Research Group Faculty of Sciences Ghent University

A Hilbert transform for H61der continuous circulant （2 × 2） matrix functions, on the d- summable （or fractal） boundary F of a Jordan domain Ω in R2n, has recently been introduced within the framework of Hermitean Clifford analysis. The main goal of the present paper is to estimate the HSlder norm of this Hermitean Hilbert transform. The expression for the upper bound of this norm is given in terms of the HSlder exponents, the diameter of F and a specific d-sum （d 〉 d） of the Whitney decomposition of Ω. The result is shown to include the case of a more standard Hilbert transform for domains with left Ahlfors-David regular boundary.

关键词： Hermitean Clifford analysis Hilbert transform fractal geometry