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Many wireless communications channels consist of multiple signal paths from the
transmitter to receiver. This multiplicity of paths leads to a phenomenon known
as multipath fading. The multiple paths are caused by the presence of objects in the
physical environment that, through the mechanisms of propagation, alter the path of
radiated energy. These objects are referred to as scatterers. In the past, researchers
often looked at ways to mitigate multipath scattering, such as in diversity systems.
Multiple-input, multiple-output (MIMO) systems, on the other hand, use multipath
diversity to their advantage; a MIMO system has the ability to translate increased
spatial diversity into increased channel capacity.
標(biāo)簽：
Multiple-Output
Multiple-Input
Channel
Models
上傳時間：
2020-05-31
上傳用戶：shancjb
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Ever since ancient times, people continuously have devised new techniques and
technologies for communicating their ideas, needs, and desires to others. Thus,
many forms of increasingly complex communication systems have appeared
over the years. The basic motivations behind each new one were to improve the
transmission fidelity so that fewer errors occur in the received message, to
increase the transmission capacity of a communication link so that more infor-
mation could be sent, or to increase the transmission distance between relay sta-
tions so that messages can be sent farther without the need to restore the signal
fidelity periodically along its path.
標(biāo)簽：
Communications
Essentials
Optical
上傳時間：
2020-05-31
上傳用戶：shancjb
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This book paves the path toward fourth generation (4G) mobile communica-
tion by introducing mobility in heterogeneous IP networks with both third
generation (3G) and wireless local area networks (WLANs), which is seen as
one of the central issues in the becoming 4G of telecommunications networks
and systems. This book presents a thorough overview of 3G networks and
standards and discusses interworking and handover mechanisms between
WLANs and the Universal Mobile Telecommunication System (UMTS).
標(biāo)簽：
Wireless
towards
WLANs
WPANs
4G
上傳時間：
2020-06-01
上傳用戶：shancjb
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There exist two essentially different approaches to the study of dynamical systems, based on
the following distinction:
time-continuous nonlinear differential equations ? time-discrete maps
One approach starts from time-continuous differential equations and leads to time-discrete
maps, which are obtained from them by a suitable discretization of time. This path is
pursued, e.g., in the book by Strogatz [Str94]. 1 The other approach starts from the study of
time-discrete maps and then gradually builds up to time-continuous differential equations,
see, e.g., [Ott93, All97, Dev89, Has03, Rob95]. After a short motivation in terms of nonlinear
differential equations, for the rest of this course we shall follow the latter route to dynamical
systems theory. This allows a generally more simple way of introducing the important
concepts, which can usually be carried over to a more complex and physically realistic
context.
標(biāo)簽：
Systems_Rainer
Introduction
Dynamical
Klages
to
上傳時間：
2020-06-10
上傳用戶：shancjb
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A kinematically redundant manipulator is a serial robotic arm that has more
independently driven joints than are necessary to define the desired pose (position
and orientation) of its end-effector. With this definition, any planar manipulator (a
manipulator whose end-effector motion is restrained in a plane) with more than
three joints is a redundant manipulator. Also, a manipulator whose end-effector can
accept aspatialposeisaredundant manipulator ifithas morethan sixindependently
driven joints. For example, the manipulator shown in Fig. 1.1 has two 7-DOF arms
mounted on a torso with three degrees of freedom (DOFs). This provides 10 DOFs
for each arm. Since the end-effector of each arm can have a spatial motion with six
DOFs, the arms are redundant.
標(biāo)簽：
Autonomous
Modeling
Planning
Robots
path
上傳時間：
2020-06-10
上傳用戶：shancjb
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Much has been written concerning the manner in which healthcare is changing, with
a particular emphasis on how very large quantities of data are now being routinely
collected during the routine care of patients. The use of machine learning meth-
ods to turn these ever-growing quantities of data into interventions that can improve
patient outcomes seems as if it should be an obvious path to take. However, the
field of machine learning in healthcare is still in its infancy. This book, kindly
supported by the Institution of Engineering andTechnology, aims to provide a “snap-
shot” of the state of current research at the interface between machine learning and
healthcare.
標(biāo)簽：
Technologies
Healthcare
Learning
Machine
上傳時間：
2020-06-10
上傳用戶：shancjb
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The PW2606B is a front-end over voltage and over current protection device. It achieves wide inputvoltage range from 2.5VDC to 40VDC. The over voltage threshold can be programmed externally orset to internal default setting. The low resistance of integrated power path nFET switch ensures betterperformance for battery charging system applications. It can deliver up to 1A current to satisfy thebattery supply system. It integrates the over-temperature protection shutdown and auto-recoverycircuit with hysteresis to protect against over current events
標(biāo)簽：
pw2606b
上傳時間：
2022-02-11
上傳用戶：
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研究一種智能掃地機器人。從硬件系統(tǒng)控制模塊設(shè)計到主要技術(shù)調(diào)試進(jìn)行了較詳細(xì)的闡述。以STM32單片機為控制核心與電機驅(qū)動、紅外線路徑識別模塊等相互協(xié)調(diào)應(yīng)用。進(jìn)行電路搭建和程序編寫。實現(xiàn)了智能掃地機器人紅外線避障和自動掃地功能,其清掃面積能達(dá)到約70%,清掃率約60%,很大程度受到自身機械機構(gòu)的限制,后期將對小車的機械結(jié)構(gòu)進(jìn)行完善。This paper studies an intelligent sweeping robot.From the hardware system control module design to the main technical debugging are described in detail.STM32 MCU is used as the control core to coordinate with motor drive and infrared path recognition module.Conduct circuit building and programming.The functions of infrared obstacle avoidance and automatic sweeping of intelligent sweeping robot are realized.Its cleaning area can reach about 70%and the cleaning rate is about 60%.Because it is limited by its own mechanical mechanism to a great extent,the mechanical structure of the car will be improved in the later stage.
標(biāo)簽：
掃地機器人
上傳時間：
2022-03-26
上傳用戶：
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為適應(yīng)雙向DC/DC功率變換的電流采樣需求,一種高精度高邊電流采樣電路被提出。其基本思想是在功率電路的高邊串入采樣電阻,借助電流鏡原理并引入偏置電流電路,將雙向電流均轉(zhuǎn)換為正向電壓輸出。通過理論分析與仿真結(jié)合的方法對電流鏡采樣原理及4種不同的偏置電流電路方案進(jìn)行對比,最后通過實驗數(shù)據(jù)驗證了高精度高邊電流采樣電路的有效性。實驗數(shù)據(jù)表明,該采樣電路可在-25~75℃的溫度工作范圍內(nèi),針對-10~＋10 A范圍內(nèi)的電流采樣實現(xiàn)優(yōu)于5%的采樣精度。Current sensing plays an important role in controlling,monitoring or protection functions of power systems.To meet the current sensing requirement of bidirectional DC/DC converters,a high-accuracy bidirectional current sensing circuit is proposed.The proposed current sensing circuit inserts a resistor in the path of the current to be sensed,while the current mirror and biased current circuit are introduced.Therefore,the bidirectional current can be expressed by positive voltage.By theoretical analysis and simulation,the sampling theory is analyzed and four biased current circuits are compared.At last,experimental results verified the proposed method.It is demonstrated that the proposed current sensing circuit can achi...
標(biāo)簽：
雙向DC電源
電流采樣
上傳時間：
2022-04-22
上傳用戶：
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Mathematical modeling has become an important part of the research and devclopment work in engineering and scicnce. Retaining a competitive edge requiresa fast path between ideas and prototypes, and in this regard mathematical modeling and simulation provide a valuable shortcut for understanding both qualitative and quantitative aspects of scientific and engineering design. To assist you in gaining this edge, COMSOL Multiphysics offers state-of-the art performance, being built from the ground up with a Java3D interface and C/C++ solvers.The Acoustics Module is an optional package that extends the COMSOL Multiphysicsmodcling cnvironment with customized user interfaces and functionality optimizcd for the analysis of acoustics. Like all modules in the COMSOL family, it provides a brary of prewritten ready-to-run models that make it quicker and casier to analyze disciplinc-specific problcms.
標(biāo)簽：
comsol
聲學(xué)模塊
上傳時間：
2022-06-19
上傳用戶：
