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One traditional view of how wireless networks evolve is of a continuous, inevitable progres-
sion to higher link speeds, combined with greater mobility over wider areas. This standpoint
certainly captures the development from first and second generation cellular systems focused
on voice support, and the early short-range wireless data networks, through to today’s 3G
cellular and mobile broadband systems; there is every confidence that the trend will continue
some way into the future.
標簽：
Networks
Ambient
上傳時間：
2020-05-26
上傳用戶：shancjb
-
Cooperation is not a natural characteristic attributed to humans. The typical human horizon is focused
on short-term gains, which might be due to our instinct-driven subconscious occupying a grander
importance than we dare to admit [1]. Cooperating with other individuals or entities, however, usually
means that short-term losses may translate into long-term gains – something history has proved to
hold true but humans for some reason rarely ever understand.
標簽：
Communications
Cooperative
上傳時間：
2020-05-27
上傳用戶：shancjb
-
Fixed-mobile.convergence.and.voice-data.networks.have.merged.next-gen-
eration,.value-added.applications.and.integrated.multimedia.services,.com-
bining. Web. browsing,. instant. messaging,. presence,. voice. over. IP,. video.
conferencing,. application. sharing,. telephony,. unified. messaging,. multi-
media.content.delivery,.etc..on.top.of.different.network.technologies..The.
convergence.of.the.communications.networks.is.motivated.by.the.need.to.
support.many.forms.of.digital.traffic.as.well.as.to.amortize.implementation.
and.operational.costs.of.the.underlying.networks..Historically,.the.approach.
to. build. and. deploy. multimedia. services. has. focused. upon. single-point.
solutions..
標簽：
Multimedia
Subsystem
Handbook
IMS
IP
上傳時間：
2020-05-27
上傳用戶：shancjb
-
Part I provides a compact survey on classical stochastic geometry models. The basic models defined
in this part will be used and extended throughout the whole monograph, and in particular to SINR based
models. Note however that these classical stochastic models can be used in a variety of contexts which
go far beyond the modeling of wireless networks. Chapter 1 reviews the definition and basic properties of
Poisson point processes in Euclidean space. We review key operations on Poisson point processes (thinning,
superposition, displacement) as well as key formulas like Campbell’s formula. Chapter 2 is focused on
properties of the spatial shot-noise process: its continuity properties, its Laplace transform, its moments
etc. Both additive and max shot-noise processes are studied. Chapter 3 bears on coverage processes,
and in particular on the Boolean model. Its basic coverage characteristics are reviewed. We also give a
brief account of its percolation properties. Chapter 4 studies random tessellations; the main focus is on
Poisson–Voronoi tessellations and cells. We also discuss various random objects associated with bivariate
point processes such as the set of points of the first point process that fall in a Voronoi cell w.r.t. the second
point process.
標簽：
Stochastic
Geometry
Networks
Wireless
Volume
and
上傳時間：
2020-06-01
上傳用戶：shancjb
-
During the past three decades, the world has seen signifi cant changes in the telecom-
munications industry. There has been rapid growth in wireless communications, as
seen by large expansion in mobile systems. Wireless communications have moved
from fi rst-generation (1G) systems primarily focused on voice communications to
third-generation (3G) systems dealing with Internet connectivity and multi-media
applications. The fourth-generation (4G) systems will be designed to connect wire-
less personal area networks (WPANs), wireless local area networks (WLANs) and
wireless wide-area networks (WWANs).
標簽：
Communications
Networking
Wireless
上傳時間：
2020-06-01
上傳用戶：shancjb
-
This book is focused on designing and developing Representational State Transfer (REST)
platforms in Rails. REST is the architectural style of the Web, consisting of a set of
constraints that, applied to components, connectors, and data elements, constitute the
wider distributed hypermedia system that we know today: the World Wide Web.
There are a few good reasons why it makes more sense to build platforms instead of just
products or applications. Platforms are like ecosystems interconnecting different
applications, services, users, developers, and partners. Platforms foster innovation through
the inputs of their direct collaborators. By providing application programming interfaces
(APIs) and software development kits (SDKs), platforms are more customer driven.
標簽：
Development
Building
RESTful
Rails
上傳時間：
2020-06-06
上傳用戶：shancjb
-
This edition of Digital Image Processing is a major revision of the book. As in
the 1977 and 1987 editions by Gonzalez and Wintz, and the 1992, 2002, and 2008
editions by Gonzalez and Woods, this sixth-generation edition was prepared
with students and instructors in mind. The principal objectives of the book
continue to be to provide an introduction to basic concepts and methodologies
applicable to digital image processing, and to develop a foundation that can
be used as the basis for further study and research in this field. To achieve
these objectives, we focused again on material that we believe is fundamental
and whose scope of application is not limited to the solution of specialized
problems. The mathematical complexity of the book remains at a level well
within the grasp of college seniors and first-year graduate students who have
introductory preparation in mathematical analysis, vectors, matrices, probability,
statistics, linear systems, and computer programming. The book website provides
tutorials to support readers needing a review of this background material
標簽：
Processing
Digital
Image
上傳時間：
2021-02-20
上傳用戶：
-
為了提高超高頻RFID系統中閱讀器在低信噪比的情況下仍具有較高的識別能力,提出一種基于FPGA系統結合軟件無線電方法實現超高頻RFID射頻前端電路方案。超高頻射頻識別系統必須符合EPC Class 1generation 2標準,所設計的電路系統以Xilinx公司的XC6SLX16-2CSG324FPGA芯片為硬件基礎,將數字基帶調制解調和中頻濾波電路在FPGA系統中設計實現,重點闡述了射頻前端電路的設計結構、AD/DA轉換電路,以及數字濾波器的設計。實驗結果表明,所設計的超高頻RFID閱讀器簡化了前端電路系統結構,提升了穩定性,增強了抗干擾能力。該電路系統在信噪比較低的情況下,能夠較好地實現915MHz頻率的射頻接收和發送。In order to improve the reader UHF RFID system still has a higher ability to identify,in the case of low signal-to-noise ratio.The UHF RFID systems must comply with EPC Class 1 generation 2 standard.In this paper,the design of the circuit system based on Xilinx＇s XC6SLX16-2CSG324 FPGA chip,and presents UHF RFID RF front-end circuit with software radio based on FPGA system.Digital baseband modem and IF filter circuit is designed and implemented in the FPGA system,and focused on designing the structure of the RF front-end circuit,AD/DA conversion circuits,and digital filter.Experimental results show that the UHF RFID reader de...
標簽：
915mhz
超高頻
rfid
閱讀
射頻
前端
電路
設計
上傳時間：
2022-04-17
上傳用戶：shjgzh
-
隨著科技的發展，人們在日常生活中使用的電器越來越多，電子設備的電磁兼容性（EMC）也越來越重要。所以，人們對電子設備的電磁兼容性的要求也越來越嚴格，越來越規范。而在市場競爭中，如何降低成本、減少設備體積，是各電子設備制造廠家重點研究的課題。通過對開關電源的EMI濾波電路的類別和相應的技術特點進行分析，設計出一種既能提高性能，又能降低成本的濾波電路。With the development of technology, appliances people use in their daily lives, more and more electronic devices electromagnetic compatibility （ EMC ） has become increasingly important. So, people electromagnetic compatibility requirements of electronic devices have become increasingly stringent, more and more standardized. The competition in the market, how to reduce costs, reduce equipment size, is the subject of the electronic equipment manufacturer focused on research. Through the technical characteristics of the respective category and the EMI filter circuit switching power supply is analyzed both designed to improve a performance of the filter circuit can reduce the cost.
標簽：
開關電源
濾波電路
上傳時間：
2022-04-23
上傳用戶：
-
近年來，對器件的失效分析已經成為電力電子領域中一個研究熱點。本論文基于現代電力電子裝置中應用最廣的IGBT器件，利用靜態測試儀3716，SEM（Scanning Electrom Microscope，掃描電子顯微鏡）、EDX（Energy Dispersive X-Ray Spectroscopy、能量色散x射線光譜儀）、FIB（focused lon beam，聚焦高子束）切割、TEM（Thermal Emmision Microscope，高精度熱成像分析儀）等多種分析手段對模塊應用當中失效的1GBT芯片進行電特性分析、芯片解剖并完成失效分析，并基于相應的失效模式提出了封裝改進方案。1，對于柵極失效的情況，本論文先經過電特性測試完成預分析，并利用THEMOS分析出柵極漏電流通路，找到最小點并進行失效原因分析，針對相應原因提出改進方案。2，針對開通與關斷瞬態過電流失效，采用研磨、劃片等手段進行芯片的解剖。并用SEM與EDX對芯片損傷程度進行評估分析，以文獻為參考進行失效原因分析，利用saber仿真進行失效原因驗證。3，針對通態過電流失效模式，采用解剖分析來評估損傷情況，探究失效原因，并采用電感鉗位電路進行實驗驗證。4，針對過電壓失效模式，采用芯片解剖方式來分析失效點以及失效情況，基于文獻歸納并總結出傳統失效原因，并通過大量實驗得出基于封裝的失效原因，最后采用saber仿真加以驗證。
標簽：
igbt
上傳時間：
2022-06-21
上傳用戶：1208020161
