Soon AFTER Samuel Morse’s telegraphing device led to a deployed electri- cal telecommunications system in 1843, waiting lines began to form by those wanting to use the system. At this writing queueing is still a significant factor in designing and operating communications services, whether they are provided over the Internet or by other means, such as circuit switched networks.
标签： Telecommunication Queueing Packet Theory with
上传时间： 2020-05-31
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It is more than a decade since GSM was first commercially available. AFTER some unexpected delay, it seems that finally UMTS is here to stay as a 3G system standardised by 3GPP, at least for another ten years. UMTS will enable multi-service, multi-rate and flexible IP native-based mobile technologies to be used in wide area scenarios and also pave the way for a smooth transition from circuit switched voice networks to mobile packet services.
标签： Management Strategies Resource Radio
上传时间： 2020-06-01
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When 3GPP started standardizing the IMS a few years ago, most analysts expected the number of IMS deploymentsto grow dramatically as soon the initial IMS specifications were ready (3GPP Release 5 was functionallyfrozenin the first half of 2002and completedshortly AFTER that). While those predictions have proven to be too aggressive owing to a number of upheavals hitting the ICT (Information and Communications Technologies) sector, we are now seeing more and more commercial IMS-based service offerings in the market. At the time of writing (May 2008), there are over 30 commercial IMS networks running live traffic, addingup to over10million IMS users aroundthe world; the IMS is beingdeployedglobally. In addition, there are plenty of ongoing market activities; it is estimated that over 130 IMS contracts have been awarded to all IMS manufacturers. The number of IMS users will grow substantially as these awarded contracts are launched commercially. At the same time, the number of IMS users in presently deployed networks is steadily increasing as new services are introduced and operators running these networks migrate their non-IMS users to their IMS networks.
标签： Multimedia Subsystem The IMS 3G IP
上传时间： 2020-06-01
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The first practical examples of mobile communications were used in many countries like the USA, the UK and Germany in military services, and played a significant role in the First World War to transfer important information from the front to headquarters to take further actions. Good and secure wireless communications were an important need for all military services – army, navy and air force. In this respect, the Second World War was a big experimental battlefield for the development and evolution of mobile radio. It was in the interests of governments that AFTER the Second World War the military investment should be paid back by civilian use, and all western European countries started their so-called first generation of mobile communication networks.
标签： Multimedia Business Mobile The
上传时间： 2020-06-01
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n the first part of this book, we give an introduction to the basic applications of wireless com- munications, as well as the technical problems inherent in this communication paradigm. AFTER a brief history of wireless, Chapter 1 describes the different types of wireless services, and works out their fundamental differences. The subsequent Section 1.3 looks at the same problem from a different angle: what data rates, ranges, etc., occur in practical systems, and especially, what combination of performance measures are demanded (e.g., what data rates need to be transmitted over short distances; what data rates are required over long distances?) Chapter 2 then describes the technical challenges of communicating without wires, putting special emphasis on fading and co-channel interference. Chapter 3 describes the most elementary problem of designing a wireless system, namely to set up a link budget in either a noise-limited or an interference-limited system. AFTER studying this part of the book, the reader should have an overview of different types of wireless services, and understand the technical challenges involved in each of them. The solutions to those challenges are described in the later parts of this book.
标签： Communications Wireless Edition 2nd
上传时间： 2020-06-01
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It has been over a decade since the Chinese publication of Line Loss in Electric Power Systems. To keep pace with technological developments, I started a revision as early as 2002, following the main principles that the theoretical framework and characteristics of the first edition should be retained, with new contents added according to new problems AFTER the reform of electric power systems and the new requirements for line loss management practices and in combination with practical experience.
上传时间： 2020-06-07
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This book is based on a Ph.D. research that has been conducted at the Delft University of Technology in the Netherlands in collaboration with Dutch Electricity & Gas Distribution Network Operator, Stedin. This book was written as a result of wider interest that was shown by different industry groups on this topic AFTER its public defence. This inspired the author to modify and publish a practical version of the research for a greater international audience. Therefore, the content of this book is intended for a double audience, on the one hand for those interested in the organisational and management aspects of maintenance.
标签： Maintenance Electricity Risk-Based Network for
上传时间： 2020-06-07
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With the continued growth in the world's population, there is a need to ensure availability of enough food to feed everyone. Advances in science and technology have helped not only to increase food production, but also to reduce food wastage. However, the latter has the potential to be improved to a significant extent through appropriate matching of supply and demand, and with proper handling during storage and transit. Given the amount of food wastage that occurs AFTER a food item leaves the “farm” on its way to the “fork,” and the availability of means to reduce such wastage, there really is no excuse for feigned ignorance.
标签： Automation Industry Network Sensor RFID Food and the in
上传时间： 2020-06-08
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RFID (radio-frequency identification) is the use of a wireless non-contact system that uses radio-frequencyelectromagnetic fields to transfer datafrom a tag attached to an object, for the purposes of automatic identification and tracking [38]. The basic technologies for RFID have been around for a long time. Its root can be traced back to an espionage device designed in 1945 by Leon Theremin of the Soviet Union,whichretransmittedincidentradiowaves modulatedwith audioinformation. AFTER decades of development, RFID systems have gain more and more attention from both the research community and the industry.
标签： Infrastructure RFID as an
上传时间： 2020-06-08
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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.
标签： Systems_Rainer Introduction Dynamical Klages to
上传时间： 2020-06-10
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