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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.
1

The effect of mass media on the short-term cognitive development on the participants at a Tarrant County extension garden seminar

Woodson, Dorothy McDaniel 29 August 2005 (has links)
The majority of the Texas population now lives in urban areas. In rural areas, the traditional Extension audience prefers to receive Extension information at an Extension meeting, from a county agent??s visit to the farm, or a farm demonstration. A rural county Extension agent can invite their target audience to a seminar and probably have almost the entire audience attend. In an urban county, most county Extension agents would not even have a location large enough to hold their target audience. The Extension seminar/meeting model has been successful for many years and will continue to meet the needs of the rural Extension audience and most urban audiences. To determine the preferred delivery method in an urban audience and test the delivery method for gain in knowledge, participants at two garden seminars were asked to complete a questionnaire after attending breakout sessions about landscape maintenance practices. The same information was delivered by different methods; newspaper, television, Extension fact sheet, and a presentation. Participants were asked questions about what they learned in each session, how they preferred to received information, what was their primary source for information, how they perceived their landscape knowledge expertise before and after treatment, and about their past contact with Extension. Results indicate a gain inknowledge from newspaper, video, fact sheet, and presentation; most participants preferred and were receiving most information about landscape maintenance from print media particularly newspaper; participants who perceived their expertise as high before and after the treatment scored higher on the landscape knowledge test; and over half the participants had some previous contact with Extension. The results may be used to guide urban county Extension agents to select education delivery methods to effectively deliver best management practice information to homeowners about landscape maintenance.
2

SELF-ADAPTIVE OPTIMAL FILTER DESIGN FOR STATISTICALLY DESCRIBABLE SIGNALS

Nabours, Robert Eugene, 1934- January 1965 (has links)
No description available.
3

Adaptive decision threshold receivers using stochastic approximation techniques

Bouvier, Maurice Joseph Bertrand 05 1900 (has links)
No description available.
4

Bandwidth-efficient communication systems based on finite-length low density parity check codes

Vu, Huy Gia 31 October 2006
Low density parity check (LDPC) codes are linear block codes constructed by pseudo-random parity check matrices. These codes are powerful in terms of error performance and, especially, have low decoding complexity. While infinite-length LDPC codes approach the capacity of communication channels, finite-length LDPC codes also perform well, and simultaneously meet the delay requirement of many communication applications such as voice and backbone transmissions. Therefore, finite-length LDPC codes are attractive to employ in low-latency communication systems. This thesis mainly focuses on the bandwidth-efficient communication systems using finite-length LDPC codes. Such bandwidth-efficient systems are realized by mapping a group of LDPC coded bits to a symbol of a high-order signal constellation. Depending on the systems' infrastructure and knowledge of the channel state information (CSI), the signal constellations in different coded modulation systems can be two-dimensional multilevel/multiphase constellations or multi-dimensional space-time constellations. In the first part of the thesis, two basic bandwidth-efficient coded modulation systems, namely LDPC coded modulation and multilevel LDPC coded modulation, are investigated for both additive white Gaussian noise (AWGN) and frequency-flat Rayleigh fading channels. The bounds on the bit error rate (BER) performance are derived for these systems based on the maximum likelihood (ML) criterion. The derivation of these bounds relies on the union bounding and combinatoric techniques. In particular, for the LDPC coded modulation, the ML bound is computed from the Hamming distance spectrum of the LDPC code and the Euclidian distance profile of the two-dimensional constellation. For the multilevel LDPC coded modulation, the bound of each decoding stage is obtained for a generalized multilevel coded modulation, where more than one coded bit is considered for level. For both systems, the bounds are confirmed by the simulation results of ML decoding and/or the performance of the ordered-statistic decoding (OSD) and the sum-product decoding. It is demonstrated that these bounds can be efficiently used to evaluate the error performance and select appropriate parameters (such as the code rate, constellation and mapping) for the two communication systems.<p>The second part of the thesis studies bandwidth-efficient LDPC coded systems that employ multiple transmit and multiple receive antennas, i.e., multiple-input multiple-output (MIMO) systems. Two scenarios of CSI availability considered are: (i) the CSI is unknown at both the transmitter and the receiver; (ii) the CSI is known at both the transmitter and the receiver. For the first scenario, LDPC coded unitary space-time modulation systems are most suitable and the ML performance bound is derived for these non-coherent systems. To derive the bound, the summation of chordal distances is obtained and used instead of the Euclidean distances. For the second case of CSI, adaptive LDPC coded MIMO modulation systems are studied, where three adaptive schemes with antenna beamforming and/or antenna selection are investigated and compared in terms of the bandwidth efficiency. For uncoded discrete-rate adaptive modulation, the computation of the bandwidth efficiency shows that the scheme with antenna selection at the transmitter and antenna combining at the receiver performs the best when the number of antennas is small. For adaptive LDPC coded MIMO modulation systems, an achievable threshold of the bandwidth efficiency is also computed from the ML bound of LDPC coded modulation derived in the first part.
5

Bandwidth-efficient communication systems based on finite-length low density parity check codes

Vu, Huy Gia 31 October 2006 (has links)
Low density parity check (LDPC) codes are linear block codes constructed by pseudo-random parity check matrices. These codes are powerful in terms of error performance and, especially, have low decoding complexity. While infinite-length LDPC codes approach the capacity of communication channels, finite-length LDPC codes also perform well, and simultaneously meet the delay requirement of many communication applications such as voice and backbone transmissions. Therefore, finite-length LDPC codes are attractive to employ in low-latency communication systems. This thesis mainly focuses on the bandwidth-efficient communication systems using finite-length LDPC codes. Such bandwidth-efficient systems are realized by mapping a group of LDPC coded bits to a symbol of a high-order signal constellation. Depending on the systems' infrastructure and knowledge of the channel state information (CSI), the signal constellations in different coded modulation systems can be two-dimensional multilevel/multiphase constellations or multi-dimensional space-time constellations. In the first part of the thesis, two basic bandwidth-efficient coded modulation systems, namely LDPC coded modulation and multilevel LDPC coded modulation, are investigated for both additive white Gaussian noise (AWGN) and frequency-flat Rayleigh fading channels. The bounds on the bit error rate (BER) performance are derived for these systems based on the maximum likelihood (ML) criterion. The derivation of these bounds relies on the union bounding and combinatoric techniques. In particular, for the LDPC coded modulation, the ML bound is computed from the Hamming distance spectrum of the LDPC code and the Euclidian distance profile of the two-dimensional constellation. For the multilevel LDPC coded modulation, the bound of each decoding stage is obtained for a generalized multilevel coded modulation, where more than one coded bit is considered for level. For both systems, the bounds are confirmed by the simulation results of ML decoding and/or the performance of the ordered-statistic decoding (OSD) and the sum-product decoding. It is demonstrated that these bounds can be efficiently used to evaluate the error performance and select appropriate parameters (such as the code rate, constellation and mapping) for the two communication systems.<p>The second part of the thesis studies bandwidth-efficient LDPC coded systems that employ multiple transmit and multiple receive antennas, i.e., multiple-input multiple-output (MIMO) systems. Two scenarios of CSI availability considered are: (i) the CSI is unknown at both the transmitter and the receiver; (ii) the CSI is known at both the transmitter and the receiver. For the first scenario, LDPC coded unitary space-time modulation systems are most suitable and the ML performance bound is derived for these non-coherent systems. To derive the bound, the summation of chordal distances is obtained and used instead of the Euclidean distances. For the second case of CSI, adaptive LDPC coded MIMO modulation systems are studied, where three adaptive schemes with antenna beamforming and/or antenna selection are investigated and compared in terms of the bandwidth efficiency. For uncoded discrete-rate adaptive modulation, the computation of the bandwidth efficiency shows that the scheme with antenna selection at the transmitter and antenna combining at the receiver performs the best when the number of antennas is small. For adaptive LDPC coded MIMO modulation systems, an achievable threshold of the bandwidth efficiency is also computed from the ML bound of LDPC coded modulation derived in the first part.
6

Communicating 21st century statecraft: Evaluating the paradigm shift argument

Chinn, Jacquelyn Nicole 2011 August 1900 (has links)
This project examines how social media is being used by individuals within the State Department engaged in public diplomacy and how the use of these technologies may or may not represent a paradigm shift in diplomatic operation. Assessments of social media and government in popular culture argue a fundamental shift has taken place in government operations. Yet this argument calls for theoretical examination using communication theory and via examination of organizational praxis. Using Ammon's criterion for paradigm shift in communications technology and diplomacy, I evaluated State's current program of social media and public diplomacy called 21st Century Statecraft. I conducted a content analysis of organizational Twitter feeds and also interviewed actors within the organization working with public diplomacy and social media. I also examined historical accounts of State's Voice of America radio program, and compared current organizational uses of social media with the appropriation of radio in the second half of the 20th century. The results suggest that paradigm shift has not yet occurred despite the uses of the new technologies. In many cases, social media is being used akin to technologies from previous paradigms due in part to the constraints of organizational structures. Twitter platforms were used as spaces to push information and policy to the masses, similar to the ways in which radio was used after World War II and throughout the Cold War. Organizational actors characterized social media as a tool to accomplish public diplomacy, not as the change agent those outside of the organization have argued it to be. They described organizational challenges of incorporating social media including questions of voice, information control, and doing 'in-reach' inside the organization. Finally, they described aspects of the interaction that took place as an opportunity to create dialogue amongst interested citizens around the world and to come into face-to-face contact with individuals outside the embassy. Although anomalous practices have begun to emerge as a result of new media's use in the State Department, we have not reached what Kuhn would term a 'critical mass,' necessitating a shift in worldview and practice.
7

Broadcast for one: paging and network communication

Morton, Benjamin Allen 01 December 2018 (has links)
This dissertation explores the history and culture of a mobile communication device and practice that has been superseded by today’s networked communication devices. The pager—known later in the 1980s and 1990s as a beeper—has a longer history than most assume. In the early 1950s the device was not a distinct technology in its own right, but a haphazard combination of existing communications technologies: telegraphy, telephony, radio broadcasting, answering services, and hearing aids. These technological origins, and the cultures that support them, are important for broadcast and telecommunications historians, as well as media history and theory in general, for three reasons. First, research on the pager fills a gap in telecommunications history that typically begins with Bell’s wired telephone and ends with wireless mobile car-phones and, later, cellular telephones. Second, the pager’s history contributes to the limited scholarship that has emphasized radio’s many directions after the major broadcast networks left radio for larger television audiences in the late 1940s and early 1950s. Being in-between telephone and radio technology has given the pager somewhat of an identity crisis for historians. Yet this is a silver lining for communication theorists to think about the connection between a medium’s physical form (e.g., a radio is a receiving device that can’t talk back) and its communication form (e.g., a pager was once known as a radio that you would use with the telephone to talk back). Lastly, the pager is not just a technological device, but the embodiment of a rarely discussed form of communication: paging. This project investigates the history of paging as a cultural technique and communication practice. While early pagers utilized both broadcast and telecommunications techniques, paging as a form of communication does not fall clearly within either of those categories. Like being paged over a public intercom system, early paging systems broadcast a message (from one to many) in order to grab the attention of a single individual (one out of many). This form of communication, this project argues, is fundamental for understanding the many contemporary discussions over the publicly-private and privately-public nature of today’s social media services.
8

Vegan voices: communicatively negotiating a food-based identity

Paxman, Christina Gabrielle 01 May 2016 (has links)
Approximately 7.5 million people in the U.S. subscribe to a vegan diet and thus don't consume any animal products such as meat, fish, dairy, or eggs. Despite the considerable growth of veganism in the last decade, little is known about how people communicate about such a seemingly restrictive diet and what implications this might have for communication theory and the growing field of food studies. Therefore, the purpose of this study was to explore how vegans communicatively negotiate their identity through the lens of Hecht's (1993) communication theory of identity (CTI). I conducted phone interviews with forty vegans residing across the U.S. and completed thematic analysis to qualitatively analyze interviews. Four themes emerged to describe the ways vegans enact their identity (Facilitating Smooth Interactions, Wearing Symbols of Veganism, Vegan Food Preparation and Consumption, Education and Community Engagement), and three themes emerged to illustrate the relational identities that vegans co-construct with members of their social network (Accepted and Supported, Inconvenience to the Family, Happiest with a Vegan (Friendly) Partner). Vegans explained that they engage in a variety of communication strategies (e.g., focusing on the positive) to thoughtfully craft an identity that will be well-received by others. Additionally, participants explained that they are not only supported by members of their social network, but that this support is an integral part of their relational identity. Lastly, I analyzed participant accounts to see if any discrepancies (i.e., identity gaps; Jung & Hecht, 2004) emerged between the ways vegans negotiate their identity. Results indicate that some vegans experience or create up to four different identity gaps between different layers of identity (Personal-Enacted Gap, Relational-Enacted Gap, Enacted-Enacted Gap, Community-Personal Gap). Implications and directions for future research are discussed.
9

The Rhetoric and Philosophy of Education: Finding Whole Learning in an Age of Mechanistic Pedagogy

Bedford, Georgia 27 July 2014 (has links)
This project examines the communicative structure of the contemporary rhetoric of crisis and reform narrative dominating public conversation about education, as a post-industrial body of discourse deeply embedded in historical ideals for a mass system of public education. In challenging the crisis-centered narrative, this work seeks to identify historical discourse strands that have shaped thinking and action in the construction of educational policy, legislation, administration and pedagogy. This work evaluates the misalignment in the assumptions which guide the perception that an academic relationship exists between higher education and secondary school which is in contrast to the original purpose for a mass system of public education. In part, this research is a response to discourse that applies responsibility to colleges and universities in the ongoing rhetoric of crisis and reform calls for greater accountability and assessments as a means by which the problems of education may be reversed. It is the position of this research that these systems are not aligned yet increasingly, public discussions about educational failures assume that secondary school is the preparatory ground for the transition to higher learning. / McAnulty College and Graduate School of Liberal Arts / Communication and Rhetorical Studies / PhD / Dissertation
10

The computation problem with sequential decoding.

January 1965 (has links)
Bibliography: p. 76-77. / Contract AF 19(628)-500

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