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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Rural sociability in the digital world

Wilson, Ruth January 2015 (has links)
The nature of sociability in the digital world has attracted much attention, with theories of the network society describing the formation of networked connections across distant geographies. Policymakers are optimistic about the potential for these new forms of connectivity to overcome some of the longstanding disadvantages of rural life. However, a prerequisite for full and meaningful participation in the network society is equal access to digital infrastructure, and a persistent urban–rural divide in this regard has been documented across Britain. The thesis argues that the meaning of the divide has been under-investigated with the result that our understanding of rural sociability in contemporary society is theoretically underdeveloped. This is addressed through a study of sociability in rural Britain, which adopts a “facet methodology” approach, examining the research problem from different angles using a range of methods. The first facet of the research compares the perceptions of rural and urban Internet users through an analysis of the Oxford Internet Survey. The second facet conducts a social network analysis of the online connections formed by a group of bloggers in the Scottish islands. The third facet explores the discursive interactions of the same set of bloggers through a thematic analysis of their writings. Together, the methods shed light on key aspects of the research problem. The findings reveal that people living in the country's rural areas are experiencing a different relationship with digital technology from urban residents. Rather than occupying peripheral or inferior positions in the network society, however, they are cultivating unique forms of digital sociability, informed by particular influences and motivations that set their social behaviour apart from the networked norm. Throughout the thesis, an understanding of the place of rural in the digital world is elaborated and the network society is shown to be differentiated across multiple dimensions.
72

Coding structure and properties for correcting insertion/deletion errors

08 August 2012 (has links)
D. Ing. / The digital transmission of information necessitates the compensation for disturbances introduced by the channel. The compensation method usually used in digital communications is error correcting coding. The errors usually encountered are additive in nature, i.e. errors where only symbol values are changed. Understandably, the field of additive error correcting codes has become a mature research field. Remarkable progress has been made during the past 50 years, to such an extent that near Shannon capacity can be reached using suitable coding techniques. Sometimes the channel disturbances may result in the loss and/or gain of symbols and a subsequent loss of word or frame synchronisation. Unless some precautions were made, a synchronisation error may propagate and corrupt large blocks of data. Typical precautions taken against synchronisation errors are: out-of-band clock signals distributed to the transmission equipment in a network; stringent requirements on clock stability and jitter; limits on the number of repeaters and regeneration to curb jitter and delays; line coding to facilitate better clock extraction; and - use of framing methods on the coding level. Most transmission systems in use today will stop data transmission until reliable synchronisation is restored. El multiplexing systems are still the predominantly used technology in fixed telephone line operators and GSM operators, and recovering from a loss of synchronisation (the FAS alarm) typically lasts approximately 10 seconds. Considering that the transmission speed is 2048 KB/s, a large quantity of data is lost in during this process. The purpose of this study is therefore to broaden the understanding of insertion/deletion correcting binary codes. This will be achieved by presenting new properties and coding techniques for multiple insertion/deletion correcting codes. Mostly binary codes will be considered, but in some instances, the results may also hold for non-binary codes. As a secondary purpose, we hope to generate interest in this field of study and enable other researchers to continue to deeper explore the mechanisms of insertion and/or deletion correcting codes.
73

Verification of a computer simulator for digital transmission over twisted pairs.

Costa, Fernando January 1990 (has links)
A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering / This dissertation verifies a Computer Simulation Package for modeling pulse transmission over digital subscriber loops. Multigauge sections on subscriber cables can be studied. The model used for each section incorporates skin, proximity and eddy current effects. The model allows important quantities such as near end echo and overall transmission distortion of pulses to be.predicted. An experimental facility has been established in the laboratory for the purpose of validating the results produced by the simulator with results obtained over real cables. The experimental facility has as far as possible been automated by making use of computer controlled equipment for direct setup or the experiment, data transfer, and analysis. The results obtained from the pulse propagation program and that obtained from measurements are in close. agreement, rendering the Computer Simulation Package useful for analysing the performance of multi gauge digital subscriber loops. / AC 2018
74

Wireless transmission of embedded mems sensor signal: an experimental study.

January 1999 (has links)
Tsang Tin-Tak. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 78-80). / Abstract also in Chinese. / Chapter CHAPTER ONE: --- INTRODUCTION --- p.2 / Literature Survey --- p.3 / Project overview --- p.4 / Chapter CHAPTER TWO: --- SENSOR --- p.6 / Chapter 2.1. --- Background --- p.6 / Chapter 2.1.1. --- Piezoresistive effect --- p.6 / Chapter 2.1.2. --- Wheatstone bridge --- p.7 / Chapter 2.2. --- Strain Gauge --- p.10 / Chapter 2.2.1. --- Experimental setup for strain gauge --- p.11 / Chapter 2.2.2. --- Position of the strain gauge --- p.12 / Chapter 2.2.3. --- Selection of the value for the resistor to complete the bridge --- p.13 / Chapter 2.3. --- Pressure sensor --- p.15 / Chapter 2.3.1. --- Structure of pressure sensor die --- p.15 / Chapter 2.3.2. --- Modeling of the pressure sensor die --- p.17 / Chapter 2.3.3. --- Alternative application of the pressure sensor die --- p.20 / Chapter CHAPTER THREE: --- WIRELESS TRANSMISSION --- p.24 / Chapter 3.1. --- Introduction --- p.24 / Chapter 3.2. --- Analogue Transmission --- p.25 / Chapter 3.2.1. --- Transmitter (MC2833) --- p.26 / Chapter 3.2.2. --- Receiver (MC13135) --- p.29 / Chapter 3.3. --- Digital transmission --- p.30 / Chapter 3.3.1. --- Advantage of using Digital transmission --- p.30 / Chapter 3.3.2. --- Digital Transmitter and receiver 1 (H2000 & RX2020) --- p.30 / Chapter 3.3.3. --- Digital Transmitter and receiver 2 (TX2) --- p.32 / Chapter 3.4. --- Comparison between the three sets of transmitter --- p.34 / Chapter 3.4.1. --- Analogue Vs Digital --- p.34 / Chapter 3.4.2. --- Number of components (Complexity) --- p.35 / Chapter 3.4.3. --- Excepted size --- p.35 / Chapter 3.4.4. --- Transmitting distance --- p.36 / Chapter 3.4.5. --- Power supply --- p.36 / Chapter 3.4.6. --- Conclusion --- p.36 / Chapter 3.5. --- The detail investigation of HX2000 and RX2020/RX2056 --- p.37 / Chapter 3.5.1. --- Transmitting distance --- p.37 / Chapter 3.5.2. --- Shape of the received signal --- p.37 / Chapter 3.5.3. --- Orientation of the chips --- p.39 / Chapter 3.5.4. --- Conclusion for the transmitter --- p.39 / Chapter CHAPTER FOUR: --- ENCODING AND DECODING CIRCUIT --- p.40 / Chapter 4.1. --- Introduction --- p.40 / Chapter 4.2. --- Serial binary converter (MAX 1240) --- p.40 / Chapter 4.2.1. --- Features of MAX1240 --- p.41 / Chapter 4.2.2. --- Implementation of MAX1240 --- p.43 / Chapter 4.2.3. --- Method to decode the signal generated by MAX1240 --- p.46 / Chapter 4.3. --- Voltage-to-Frequency Converter (AD654) --- p.52 / Chapter 4.3.1. --- Advantages of using AD654 as the A/D converter --- p.54 / Chapter 4.3.2. --- Disadvantages of using AD654 as the A/D converter --- p.55 / Chapter 4.3.3. --- Method to read the frequency --- p.56 / Chapter 4.4. --- Frequency counter --- p.57 / Chapter 4.4.1. --- Schmitt trigger NAND-gate --- p.58 / Chapter 4.4.2. --- Ripple counter --- p.61 / Chapter 4.4.3. --- Implementation of the counter --- p.63 / Chapter 4.5. --- Conclusion --- p.66 / Chapter CHAPTER FIVE: --- INTERGATION OF THE THREE COMPONENTS --- p.67 / Implementation of the Circuit --- p.67 / Chapter 5.2. --- The result before transmission --- p.70 / Chapter 5.2.1. --- Analysis and Discussion for the experimental result (before transmission) --- p.72 / Chapter 5.3. --- The result after transmission --- p.74 / Chapter 5.3.1. --- Analysis and Discussion for the experimental result (after transmission) --- p.76 / Chapter CHAPTER SIX: --- SUMMARY --- p.77 / BIBLIOGRAPHY --- p.78
75

A simple RLS-POCS solution for reduced complexity ADSL impulse shortening

Helms, Sheldon J. 03 September 1999 (has links)
Recently, with the realization of the World Wide Web, the tremendous need for high-speed data communications has grown. Several access techniques have been proposed which utilize the existing copper twisted pair cabling. Of these, the xDSL family, particularly ADSL and VDSL, have shown great promise in providing broadband or near-broadband access through the common telephone lines. A critical component of the ADSL and VDSL systems is the guard band needed to eliminate the interference caused by the previously transmitted blocks. This guard band must come in the form of redundant samples at the start of every transmit block, and be at least as long as the channel impulse response. Since the required guard band length is much greater than the length of the actual transmitted samples, techniques to shorten the channel impulse response must be considered. In this thesis, a new algorithm based on the RLS error minimization and POCS optimization techniques will be applied to the channel impulse-shortening problem in an ADSL environment. As will be shown, the proposed algorithm will provide a much better solution with a minimal increase in complexity as compared to the existing LMS techniques. / Graduation date: 2000
76

Analytical evaluation of wireless digital communication performance over fading channels

Lo, Chi-ming. January 2001 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 159-167).
77

Cross layer design and optimization of wireless networks /

Yin, Hujun. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 118-130).
78

EXTRAPOLATION TECHNIQUES FOR THE EVALUATION OF DIGITAL COMMUNICATIONS EQUIPMENT

Davis, George Robert January 1979 (has links)
No description available.
79

Further characterization of guided scrambling line codes

Fair, Ivan J. 31 July 2015 (has links)
Graduate
80

An ISDN environment for the NeXT machine

Newton, Christopher A. January 1991 (has links)
No description available.

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