Dissertations / Theses: 'Science communications'

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Radford, Benjamin. "Misinformation in eating disorder communications| Implications for science communication policy." Thesis, State University of New York at Buffalo, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1546959.

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Though eating disorders are a serious public health threat, misinformation about these potentially deadly diseases is widespread. This study examines eating disorder information from a wide variety of sources including medical journals, news reports, and popular social activist authors. Examples of misinformation were identified, and three aspects of eating disorders (prevalence, mortality, and etiology) were chosen as key indicators of scientific illiteracy about those illnesses. A case study approach was then adopted to trace examples of misinformation to their original sources whenever possible. A dozen examples include best-selling books, national eating disorder information clearinghouses; the news media; documentary feature films; and a PBS television Nova documentary program. The results provide an overview of the ways in which valid information becomes flawed, including poor journalism, lack of fact-checking, plagiarism, and typographical errors. Less obvious—and perhaps even more important—much of the misinformation results from scientific research being co-opted to promote specific sociopolitical agendas. These results highlight a significant gap in science communication between researchers, the medical community, and the public regarding these diseases, and recommendations to address the problem are offered.

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Lacayo, Virginia. "Communicating Complexity: A Complexity Science Approach to Communication for Social Change." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367522049.

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Abramsky, R. S. "Lay empowerment in science." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/33212.

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The thesis examines the nature and effectiveness of the communications system by which information about science reaches those not professionally involved with the subject. The range and diversity of individual engagements with science, has been explored, as have the links between such engagements and people's other non-professional activities and objectives.

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Terzic, Marilyn. "Understanding television: the art and science of aesthetic response." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104508.

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This dissertation examines the processes of perception and cognition and demonstrates their application to the creation of aesthetically and artistically significant television content. By reexamining past understandings and assumptions, the ways in which artists and media producers have manipulated the information search and processing faculties of their audiences, and thus guided the meanings they ascribed to still and moving images, are explored. To reflect the multidisciplinary nature of television aesthetics, this research is not limited to a particular academic discipline. Instead, it draws on several streams of research and scholarship (media studies, marketing, psychology, neuroscience, and the fine arts) to bridge the gap between scientific theory and artistic practice and, in turn, develop effective guidelines for the construction of audiovisual materials that fulfill all three functions of the arts: the intensification, clarification, and interpretation of experience.
Cette thèse étudie les processus de perception et de cognition et démontre leurs applications à la création de contenu télévisuel ayant une valeur artistique et esthétique. En réexaminant les connaissances et hypothèses antérieures, les façons dont les artistes et les producteurs de médias ont manipulé les facultés de traitement des informations de leurs auditoires, et donc la signification qu'ils attribuaient à des images fixes et animées, sont explorées. Pour refléter la nature multidisciplinaire de l'esthétique de la télévision, cette recherche ne se limite pas à une discipline académique particulière. Au lieu de cela, elle s'appuie sur divers courants de recherche et domaines d'érudition (études sur les médias, le marketing, la psychologie, les neurosciences, et les beaux-arts) pour combler le fossé entre la théorie scientifique et la pratique artistique, afin de formuler des recommandations visant à la création de matériel audiovisuel qui remplit les trois fonctions de l'art: l'intensification, la clarification, et l'interprétation de l'expérience.

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Vantine, Karin. "Communications sourcebook /." Online version of thesis, 1992. http://hdl.handle.net/1850/11867.

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Fay, Leon. "Equalizers for communications satellites." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45992.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.
Includes bibliographical references (p. 57).
This thesis investigates equalization for advanced protected satellite communications systems in development at MIT Lincoln Laboratory. Equalizers facilitate high data rate communication by correcting dispersion in the transmitter and receiver signal chains. An automated calibration procedure for finding optimal equalizers was developed. Repeated testing addressed questions about noise amplification, filter complexity requirements, and narrow band performance degradation. After examining various architectures, it was determined that the FIR filter was the best equalizer structure given the nature of the channel. The basic calibration procedure was also extended for use at high RF frequencies by using a spectrum analyzer as a tuned receiver.
by Leon Fay.
M.Eng.

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Yu, Hua-Long. "Testability-directed specification of communications software." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7560.

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In this thesis, we make a contribution to improving software testability by providing a useful model and guide-lines for constructing highly testable specifications of distributed real time (communications) systems. A global events model is developed based on relative clock for interpreting concurrent aspect of a communications system. Extended trace assertion language (ETAL) is presented for formally representing both the sequential and concurrent aspects of the system. A relative clock based specification in ETAL method also facilitates subsequent testing activity. Subsequently, based on the global events model, a new test result analysis approach including timing information is presented for communication service and protocol conformance testing. This approach is also ETAL specification-based. After the descriptions of the contributions mentioned above, the definition of a testability-directed specification and a study on the relations between the testability-directed specification and ETAL are then presented. Finally, the feasibility and usefulness of the relative clock based formal specification method is demonstrated by its application to OSI transport software (service and protocol). Also, the effectiveness of the relative clock based approach for test result analysis is illustrated in a set of realistic conformance testing examples. (Abstract shortened by UMI.)

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Mao, Chunxu. "Integrated filtering antennas for wireless communications." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/69475/.

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In traditional radio frequency (RF) front-end subsystems, the passive components, such as antennas, filters, power dividers and duplexers, are separately designed and cascaded via the 50 Ω interfaces. This traditional approach results in a bulky and heavy RF front-end subsystem, and suffers from compromised efficiency due to the losses in the interconnections and the mismatching problems between different components. The frequency responses of the antennas such as the frequency selectivity and bandwidth are usually degraded, especially for microstrip antennas. To improve the frequency responses and reduce the size of RF front ends, it is important to investigate novel highly integrated antennas which exhibit multiple functions such as radiation, filtering, power dividing and combining or duplexing, simultaneously. In this thesis, several innovative designs of compact, multi-functional integrated an-tennas/arrays are proposed for wireless communication applications. First, new methods of designing integrated filtering antenna elements with broadband or dual-band performance are investigated. These antennas also feature high frequency selectivity and wideband harmonic suppression. Based on these studies, several integrated filtering array antennas with improved gains and frequency responses are developed for the first time. Compared with traditional array antennas, these proposed antennas exhibit improved bandwidths, out-of-band rejection and wideband harmonic suppression. The application of the filtering antennas in millimeter-wave (mm-Wave) frequency band is also investigated as it can potentially reduce the cost of the mm-Wave front-end subsystems significantly while providing the improved impedance bandwidth. The integrated design techniques are further developed to design novel dual-port highly integrated antennas with filtering and duplexing functions integrated. Such a new concept and the prototypes could find poten-tial applications in wireless communication systems and intelligent transportation system (ITS). In this thesis, comprehensive design methodologies and synthesis methods are provid-ed to guide the design of the integrated filtering antennas. The performance is evaluated with the help of full-wave electromagnetics (EM) simulations. All of the prototypes are fabricated and tested for validating the design concepts. Good agreement between the simulation and measurement results is achieved, demonstrating the integrated antennas have the advantages of compact size, flat gain performance, low losses and excellent harmonic suppression performance. These researches are important for modern wireless communication systems.

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Carter, Nicholas Brent. "The communication of science to the public: A philosophy of television /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487944660929608.

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Rugbeer, Hemduth. "Communicating by ordering electrons : the development of electronic communication as part of a secondary school Communication Science curriculum in the Language, Literacy and Communication learning area." Thesis, University of Zululand, 2001. http://hdl.handle.net/10530/314.

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A thesis submitted in fulfilment of the requirements for the Degree of MA in Communication Science, University of Zululand, 2001.
In this thesis I focus on the introduction of Electronic Cornmunication as part of an envisaged Communication Science curriculum in the Language, Literacy and Communication Learning area of the Further Education and Training band. In the course of my thesis I will show that the requisite elements of verbal and written cornmunication are dispersed throughout the Language, Literacy and Communication learning area in the General Education and Training band, and that they can be utilised as basis for formally introducing Communication Science, as a subject in the Language, literacy and Communication learning area in the Further Education and Train¬ing band. I also show that electronic communication will form a crucial area of study in such a Communication Science curriculum. I argue that due to the diversity of cultures in South Africa, cross-cultural cornmunication is required in such a curriculum. I also argue that by the very na¬ture of Outcomes-Based Education it is necessary to have a subject into our school curriculum that will form an interface with conceptual learning and experiential learning, that will contextu-alise language study within the more comprehensive scope of forms of human communication, and that will form an interface between the humanities and science to prevent the humanities from becoming soft options in Further Education and Training band learning programmes. To this effect I focus on the crucial role of Constructivism as integrating theory to account for vari¬ous approaches to motivational learning, the primary form of learning required in Outcomes-Based Education. I examine the principles of curriculum construction in OBE and its associated culture of learn¬ing against the backdrop of the theory of Situated Cognition. This presents a platform to argue the case for Electronic Communication as part of Communication Science in the Further Edu¬cation and Training band curricula in South African schools.
National Research Foundation

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Luchina, Anna, and Giacomo Codazzi. "Marketing Communication Strategy for a Science Park." Thesis, Högskolan Dalarna, Företagsekonomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:du-30795.

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Background: World economy of the 21st century places high demands on national economic systems. Governments implement various initiatives to enable a more effective cooperation between universities and industries in order to increase competitiveness of their economies. Science Parks represent one type of such initiatives. It is assumed that they support regional economic growth by means of technology transfer from university to industry. Science Parks usually incorporate incubation programs, which enable creation of NTBFs by university staff and students. Science Parks have to ensure its organizational development by providing paid services, especially in form of incubator program. Therefore, Science Parks are regarded in our research as service companies. In order to enable creation of NTBFs Science Parks have to be able to attract talented researchers and students. In our research, we focus on students and consider them as potential customers for Science Parks. Previous research focusing on the problem of students’ attraction to these organizations is scarce. We implement marketing communication theory to address the problem of students’ attraction to Science Parks. Aim: Our research is set to identify content for a marketing communication strategy of a science park, which considers students as potential customers. Theoretical background/Methodology: In order to fulfill the aim of the research we implement case study strategy. We collected primary and secondary data. The case organization is presented by Dalarna Science Park (located in Borlänge, Sweden), where we collected secondary data. It was incorporated in our research as handout materials that enabled Focus Group discussions. Focus groups with students from Dalarna University presented the source of primary data. Question guideline for focus groups was based on principles of marketing communication theory, which we used as the primary theory of the research. Conclusions: Results indicate that students regard business incubator services of a Science Park as useful for those who have business ideas. It can be considered as positive prerequisite for a marketing communication strategy. In order to attract students with ideas of starting own ventures, a Science Park should engage students into various events, such as workshops, discussions and seminars. The organization should constantly inform students about its nature and activities and create an image of a young successful entrepreneur, which students are attracted to. For this purpose a Science Park can use Internet as means of both spreading its messages to students and enabling WOM recommendations among them.

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Xu, Zhe. "Real-time expressive Internet communications." Thesis, Bournemouth University, 2005. http://eprints.bournemouth.ac.uk/437/.

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This research work "Real-time Expressive Internet Communications" focuses on two subjects: One is the investigation of methods of automatic emotion detection and visualisation under real-time Internet communication environment, the other is the analysis of the influences of presenting visualised emotion expressivei mages to Internet users. To detect emotion within Internet communication, the emotion communication process over the Internet needs to be examined. An emotion momentum theory was developed to illustrate the emotion communication process over the Internet communication. It is argued in this theory that an Internet user is within a certain emotion state, the emotion state is changeable by internal and external stimulus (e.g. a received chat message) and time; stimulus duration and stimulus intensity are the major factors influencing the emotion state. The emotion momentum theory divides the emotions expressed in Internet communication into three dimensions: emotion category, intensity and duration. The emotion momentum theory was implemented within a prototype emotion extraction engine. The emotion extraction engine can analyse input text in an Internet chat environment, detect and extract the emotion being communicated, and deliver the parameters to invoke an appropriate expressive image on screen to the every communicating user's display. A set of experiments were carried out to test the speed and the accuracy of the emotion extraction engine. The results of the experiments demonstrated an acceptable performance of the emotion extraction engine. The next step of this study was to design and implement an expressive image generator that generates expressive images from a single neutral facial image. Generated facial images are classified into six categories, and for each category, three different intensities were achieved. Users need to define only six control points and three control shapes to synthesise all the expressive images and a set of experiments were carried out to test the quality of the synthesised images. The experiment results demonstrated an acceptable recognition rate of the generated facial expression images. With the emotion extraction engine and the expressive image generator,a test platform was created to evaluate the influences of emotion visualisation in the Internet communication context. The results of a series of experiments demonstratedthat emotion visualisation can enhancethe users' perceived performance and their satisfaction with the interfaces. The contributions to knowledge fall into four main areas; firstly, the emotion momentum theory that is proposed to illustrate the emotion communication process over the Internet; secondly, the innovations built into an emotion extraction engine, which senses emotional feelings from textual messages input by Internet users; thirdly, the innovations built into the expressive image generator, which synthesises facial expressions using a fast approach with a user friendly interface; and fourthly, the identification of the influence that the visualisation of emotion has on human computer interaction.

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Leuca, Magdalena. "Security issues in wireless communications." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10266.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
Includes bibliographical references (leaves 99-103).
by Magdalena Leuca.
M.Eng.

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14

Papastavrou, Jason D. "Distributed detection with selective communications." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15013.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 117-118.
by Jason D. Papastavrou.
M.S.

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15

Aleem, Syed A. "Protocol engineering issues for open systems communications." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/6011.

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In this thesis we present real design criteria and design building blocks in a highly procedural way starting from the specification to the implementation stage. A subset of a real protocol, namely ISDN Q.931 (CCIT3), written in informal English will be translated to a formal specification using Estelle as the formal description technique. A means of incorporating the design criteria into the formal description of the protocol is presented and illustrated with Q.931 as example. This thesis will also derive the services a protocol expects from the operating system. Those services will be summarized and standardized in order to limit variability in the design process of a protocol. The system interface which has been a major source of variation in protocol implementation, will reduce to a set of a few well defined standard system calls by assuming a proposed standard operating system interface. This interface standard appears to be sufficient to allow the automatic development of complete protocol software. (Abstract shortened by UMI.)

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Lei, Zhijun. "Video transcoding techniques for wireless video communications." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/29134.

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The transmission of compressed video over channels with different capacities may require a reduction in bit rate if the transmission channel has a lower capacity than the capacity required by the video bit-stream, or when the channel capacity is changing over time. The process of converting a compressed video format into another compressed format is known as transcoding. This thesis addresses the specific transcoding problem of dynamic bit-rate adaptation for transmission over low bandwidth wireless channels. Transmitting compressed video over lower bandwidth wireless channels require accurate and efficient rate-control schemes. In this thesis, we propose several techniques to improve transcoding performance. Based on our experimental results, we present an approximate linear bit allocation model and macroblock layer rate-control algorithm, which can achieve accurate transcoding bit-rate. By reusing useful statistics information from the incoming compressed video, the bit-rate of the transcoded video can be determined according to the video scene context. Considering a specific bursty error wireless channel, we propose a solution which combines video transcoding and an ARQ protocol to transmit compressed video over this channel. In order to make sure that the end decoder can decode and play the transcoded video within the required end-to-end delay, we analyze the rate and buffer constraints of the transcoder and derive the conditions that have to be met by the transcoder. In order to test the proposed solution, we use a statistical channel model to simulate the wireless channel and use this model and channel observation to estimate the effective channel bandwidth, which will be fed back to the transcoder for better rate control. In this thesis, we discuss two applications. For real time video communication over wireless channel, we propose an algorithm that determines the transcoding scaling factor considering end-to-end delay, buffer fullness and effective channel bandwidth. For pre-encoded video distribution over wireless channels, we propose an algorithm which can determine the transcoding bit budget based on end-to-end delay, effective bandwidth, and original video bit profile. The proposed algorithm outperforms H.263 TMN8 in terms of video quality and buffer behavior with the same computational requirements.

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Sun, Min-Te. "Supporting communications in ad hoc network systems /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486462702466432.

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Giroudeau, Rodolphe. "ordonnancement et communications." Habilitation à diriger des recherches, Université Montpellier II - Sciences et Techniques du Languedoc, 2012. http://tel.archives-ouvertes.fr/tel-00797855.

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Dong, Chen. "Buffer-aided multihop wireless communications." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/364737/.

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In this thesis, we propose a suite of buffer-aided transmission schemes designed for a multihop link or for a three-node network by exploiting the characteristics of buffer-aided transmissions. Our objective is to improve the end-to-end BER, outage probability, throughput and energy dissipation. Specifically, we firstly proposed and studied a buffer-aided multihop link (MHL), where all the relay nodes (RNs) are assumed to have buffers for temporarily storing their received packets. Hence, the RNs are operated under the so-called store-and-forward (SF) relaying scheme. As a benefit of storing packets at the RNs, during each time-slot (TS), the best hop having the highest signal-to-noise ratio (SNR) can be activated from the set of those hops that have packets awaiting transmission in the buffer. A packet is then transmitted over the best hop. This hop-selection procedure is reminiscent of selection (SC) diversity, which is referred to here as multi-hop diversity (MHD), when assuming that each hop experiences both propagation pathloss and independent identically distributed (i.i.d) flat Rayleigh fading. In order to make the channel activation practical, a MAC layer implementation is proposed and several closed-form formulas are derived for its characterization. Then we studied the buffer-aided multihop link, when assuming that each hop experiences both propagation pathloss and independent non-identically distributed (i.n.i.d) at Nakagami-m fading. Both BPSK as well as M-ary quadrature amplitude modulation (MQAM) are employed. During each TS, the MHD scheme activates the specific hop's transmission, whose signal-to-noise ratio (SNR) cumulative distribution function (CDF) gives the highest ordinate value amongst all the available hops. The next packet is then transmitted over the selected hop. This CDF-aware MHD scheme is suitable for operation in the scenarios, where the different hops may have different length, hence resulting in different average SNRs, and/or experience different types of fading. This MHD scheme is also capable of achieving the maximum attainable diversity gain provided by the independent fading experienced by the different hops. Then the benefits of adaptive modulation are exploited, where the number of bits transmitted in each TS is affected both by the channel quality and the buffer fullness. During each TS, the criterion used for activating a specific hop is that of transmitting the highest number of bits (packets). When more than one hops are capable of transmitting the same number of bits, the particular hop having the highest channel quality (reliability) is activated. Hence we refer to this regime as the Maximum Throughput Adaptive Rate Transmission (MTART) scheme. Additionally, a new MAC layer protocol is proposed for implementing our MTART management. Finally, we propose and study a routing scheme, namely the Buffer-aided Opportunistic Routing (BOR) scheme, which combines the benefits both opportunistic routing and MHD transmission. It is conceived for the transmission of information in a Buffer-aided Three-node Network (B3NN) composed of a Source Node (SN), a buffer-aided Relay Node (RN) and a Destination Node (DN). When applying opportunistic routing, each packet is transmitted from SN to DN either directly or indirectly via a RN based on the instantaneous channel quality. When applying MHD transmission, the RN is capable of temporarily storing the received packets, which facilitates transmission over three links, namely the SR, RD and SD links. In this network, the three channels define a 3D channel probability space (CPS), which is divided into four regions representing the activation-region of the three channels and an outage region. Then the instantaneous channel quality values map to a specific point in this 3D channel space. The BOR scheme relies on the position of this point to select the most appropriate channel in the 3D CPS for its transmission. In comparison to the benchmark schemes considered in the literature, the BER, the OP, throughput and/or energy dissipation of our proposed systems are significantly improved.

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Xu, Chao. "Reduced-complexity communications system design." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/381515/.

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The technical breakthrough of Turbo Codes (TCs) initiated two decades of exciting developments leading to a suite of near-capacity techniques. It has been widely recognized that exchanging extrinsic information between the channel decoders and the modulated signal detectors assists communications systems in approaching their best possible performance potential that is predicted by the channel capacity. Nonetheless, in line with Moor’s Law, as researchers inch closer and closer to the channel capacity, the complexity of the resultant communications systems is also significantly increased. In fact, soft-decision-aided signal detection conceived for Single-Input Single-Output (SISO), Single-Input Multiple-Output (SIMO) and Multiple-Input Multiple-Output (MIMO) schemes typically contribute a substantial fraction of the total complexity, especially when multiple received samples have to be jointly detected in order to combat the deleterious effect of channel fading. Against this background, in this treatise, we firstly propose a reduced-complexity design for the classic soft-decision-aided PSK/QAM detectors, and then these reduced-complexity design guidelines are applied to a variety of communications systems spanning from coherent to non coherent, from uncoded to coded, and also from SISO to MIMO systems. Our aim is to reduce the computational complexity as much as possible, especially for complex near-capacity communications systems, while mitigating any performance loss imposed by our reduced-complexity design. First of all, we commence from the family of basic coherent SISO/SIMO systems, where both uncoded and coded PSK/QAM schemes are considered. The channel coding assisted near capacity systems design principles are introduced based on EXtrinsic Information Transfer (EXIT) charts. Furthermore, we observe that the Max-Log-MAP algorithm invoked for soft-decision-aided PSK/QAM detection aims for finding the maximum probabilities, which is similar to the action of hard-decision-aided detection of uncoded MPSK/QAM schemes. Therefore, we propose to link each a priori LLR to a reduced-size fraction of the channel’s output signal constellations, so that the Max-Log-MAP algorithm may be operated at a reduced complexity. Moreover, the corresponding reduced-complexity Approx-Log-MAP algorithm is also conceived by compensating for the Max-Log-MAP algorithm’s widely-used Jacobian approximation relying on a lookup table. Our performance results demonstrate that up to 41.6% and 72.6% complexity reductions are attained for soft-decision-aided Square 64QAM and Star 64QAM detectors, respectively, which is achieved without any performance loss. This complexity reduction is substantial, especially when the soft decision-aided signal detectors are invoked several times during turbo detection. Secondly, we proceed by conceiving reduced-complexity algorithms for the non coherently detected DPSK schemes in both uncoded and coded SISO/SIMO systems. More explicitly, the DPSK transmitter modulates the data-carrying symbols onto the phase changes between consecutive transmitted symbols, so that the Conventional Differential Detection (CDD) may recover the source information by observing the phase change between every pair of consecutive received samples. However, the CDD aided DPSK suffers from a 3 dB performance penalty compared to its coherent counterpart. Moreover, an irreducible error floor occurs, when the CDD is employed in rapidly fluctuating fading channels. In order to mitigate this problem, Multiple-Symbol Differential Detection (MSDD) may be invoked in order to improve the DPSK performance by extending the observation window length from the CDD’s Nw = 2 to Nw ≥ 2. The price paid is that the MSDD complexity grows exponentially with (Nw − 1) as a result of jointly detecting the (Nw − 1) data-carrying symbols. As a remedy, the Decision-Feedback Differential Detection (DFDD) concept may be introduced in order to detect a single symbol based on previous decisions concerning the (Nw − 2) data-carrying symbols in a MSDD window. However, the DFDD inevitably imposes a performance loss due to its inherent error propagation problem. In order to retain the optimal MSDD performance, the Multiple-Symbol Differential Sphere Detection (MSDSD) facilitates the MSDD by invoking a Sphere Decoder (SD). Against this background, we firstly propose to introduce a simple correlation operation into the hard-decision-aided MSDSD employing an arbitary number of Receive Antennas (RAs), so that the SD may visit the constellation points in a zigzag fashion for the case of uncoded DPSK SIMO systems. Furthermore, we propose a reduced-complexity Schnorr-Euchner search strategy for the soft-decision MSDSD employing an arbitrary number of RAs, so that the optimum candidate may be found by visiting a reduced-size subset of constellation points, and then the rest of the constellation points may be visited in a zig-zag fashion. Our simulation results demonstrate that up to 88.7% complexity reduction is attained for MSDSD (Nw = 4) aided D16PSK. We have also proposed the near-optimum Approx-Log-MAP algorithm conceived for soft-decision-aided SD, which has not been disseminated in the open literature at the time of writing. Furthermore, the important subject of coherent versus non coherent detection is discussed in the context of coded systems, which suggests that MSDSD aided DPSK is an eminently suitable candidate for turbo detection assisted coded systems operating at high Doppler frequencies. Following this, a range of non coherent detectors designed for non-constant modulus Differential QAM (DQAM) schemes are introduced for both uncoded and coded scenarios, where the open problem of MSDSD aided Differential QAM (DQAM) is solved. More explicitly, the MSDSD relies on the knowledge of channel correlation, which is determined both by the Doppler frequency and by the noise power. For DPSK, the transmitter’s phases may form a unitary matrix, which may be separated from the channel’s correlation matrix, so that a lower triangular matrix that is created by decomposion from the inverse of the channel’s correlation matrix may be utilized in the context of sphere decoding. However, for DQAM, the transmitted symbol-amplitudes cannot form a unitary matrix, which implies that they have to be taken into account by the channel’s correlation matrix. As a result, the symbol-amplitude-dependent channel correlation matrix only becomes known, when all the symbol-amplitudes are detected. Furthermore, the classic DFDD solutions conceived for DQAMrely on the assumption of the channel’s correlation matrix being independent of the symbol-amplitudes, which implies that these DFDD solutions are sub-optimal and they are not equivalent to the decision-feedback aided version of the optimum MSDD. To circumvent these problems, we prove that although the complete channel correlation matrix remains unknown, the associated partial channel correlation matrix may be evaluated with the aid of the SD’s previous decisions as well as by relying on a single information-dependent symbol amplitude that may be readily found by the SD. As a benefit, we are able to invoke sphere decoding for both amplitude detection and phase detection in the context of MSDD aided DQAM. Furthermore, we have also improved the classic DFDD solutions conceived for DQAMby directly deriving them from the optimum MSDD. Moreover, we offer a unified treatment of diverse non coherent detectors, including CDD,MSDD,MSDSD and DFDD for a variety of DQAM constellations that exist in the literature, including Differential Amplitude Phase Shift Keying (DAPSK), Absolute-Amplitude Differential Phase Shift Keying (ADPSK) and their twisted constellations. The reduced-complexity algorithms proposed for DPSK detection are also applied to DQAM detection in both uncoded and coded systems.

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Doser, Adele Beatrice 1967. "Multiple user communications for telescience." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/291989.

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This thesis presents a software development which allows multiple users to command, control, and communicate with an experiment occurring at some distant location. These functions were implemented through the modification of software already in existence in the Telescience Laboratory. There were two important items which needed to be developed in order to accommodate the desired transition: handling multiple connections and managing user privileges. The former was implemented by the reformulation of TCP/IP protocol software. The second item necessitated the development of a key assignment scheme. Steps leading up to the final design are discussed. The software package OASIS is used throughout to constitute the user-machine interface. As an application for this multiple user technology, a simulation of a Martian oxygen production plant is commanded and controlled remotely.

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Bhardwaj, Manish 1976. "Communications in the observation limited regime." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53191.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 141-145).
We consider the design of communications systems when the principal cost is observing the channel, as opposed to transmit energy per bit or spectral efficiency. This is motivated by energy constrained communications devices where sampling the signal, rather than transmitting or processing it, dominates energy consumption. We show that sequentially observing samples with the maximum a posteriori entropy can reduce observation costs by close to an order of magnitude using a (24,12) Golay code. This is the highest performance reported over the binary input AWGN channel, with or without feedback, for this blocklength. Sampling signal energy, rather than amplitude, lowers circuit complexity and power dissipation significantly, but makes synchronization harder. We show that while the distance function of this non-linear coding problem is intractable in general, it is Euclidean at vanishing SNRs, and root Euclidean at large SNRs. We present sequences that maximize the error exponent at low SNRs under the peak power constraint, and under all SNRs under an average power constraint. Some of our new sequences are an order of magnitude shorter than those used by the 802.15.4a standard.
(cont.) In joint work with P. Mercier and D. Daly, we demonstrate the first energy sampling wireless modem capable of synchronizing to within a ns, while sampling energy at only 32 Msamples per second, and using no high speed clocks. We show that traditional, minimum distance classifiers may be highly sensitive to parameter estimation errors, and propose robust, computationally efficient alternatives. We challenge the prevailing notion that energy samplers must accurately shift phase to synchronize with high precision.
by Manish Bhardwaj.
Ph.D.

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23

Barber, Thomas J. (Thomas James). "BodyLAN--a low-power communications system." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/32684.

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24

Azizoá¸¡lu, Murat. "Phase noise in coherent optical communications." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13463.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1991.
Includes bibliographical references (p. 201-206).
by Murat AzizoÄlu.
Ph.D.

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25

Zhu, Keqin. "QoS-based multicast routing for real-time communications." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/29007.

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This thesis studies the distributed multicast routing algorithms that provide quality of service (QoS) guarantees in networks. It focuses on the delay constrained minimum cost tree (or constrained Steiner tree) problem; that is, it constructs a multicast tree that not only meets the constrained end-to-end delay requirements but also is the minimum cost multicast tree. This problem is known to be NP-complete. The existing distributed multicast routing algorithms that are based on heuristics do not consider a network environment where node failures occur. As a result, these algorithms will fail to complete the construction of a multicast tree when node failures occur during the construction period. Moreover, they will fail to maintain the constructed multicast tree if node failures occur after the construction period and during the on-going multicast session. In both cases, these algorithms will have to be restarted. We propose two new distributed delay constrained multicast routing algorithms that provide QoS guarantees even in networks where node failures occur. One is shortest path (SP) based and the other is minimum spanning tree (MST) based. They are capable of constructing a delay constrained multicast tree when node failures occur during the tree construction period and recovering from any node failure in a multicast tree during the on-going multicast session without interrupting the running traffic on the unaffected portion of the tree. The proposed SP-based or MST-based algorithms perform the failure recovery efficiently, which give better performance in terms of the number of exchanged messages and the convergence time than the existing distributed SP-based or MST-based delay constrained multicast routing algorithms in a network where node failures occur, respectively. The existing distributed delay constrained multicast routing algorithms can be classified either as an MST-based heuristic or as a SP-based heuristic. Two representative algorithms i.e., DKPP and DSPH are MST and SP based heuristics, respectively. The MST based algorithms like DKPP run with a high message and time complexity of O(n3). (Abstract shortened by UMI.)

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26

Quesnell, Bethany. "Trust me, I have a PhD: the effects of religion, political conservatism, and exposure to science feature stories on trust in science." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/19709.

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Master of Science
Journalism and Mass Communications
Joye C. Gordon
Widespread debates about scientific issues, from global warming to vaccinations, have raised questions about public trust in science and scientists. Many studies have attempted to determine the cause of observed declines in public trust. This project employs framing theory, suggesting that the way science frames research might improve public trust. Research questions explore whether political conservatism, public religiosity, and exposure to a feature story about a scientist affects trust in science and scientists. A between-subjects quasi-experiment exposed participants to feature articles about scientists in either controversial or non-controversial fields, and asked a series of questions in order to measure the participant’s trust in science and scientists. Results indicated that participants who were male or participants who had some college education and who read the non-controversial feature story were statistically more likely to have a higher level of trust in science and scientists than any other group. Suggestions for future studies are discussed.

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27

Chiu, William Franklin. "The Internet, Political Communications Research and the Search for a New Information Paradigm." Thesis, University of California, Irvine, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3565847.

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The Internet, as a digital record of human discourse, provides an opportunity to directly analyze political communicative behavior. The rapid emergence of social online networks augurs a transformation in the quality and quantity of information people have to evaluate their political system. Digital formats instantiate new categories of actors and new capacities to intervene in political discourse. Existing theories of political communication fail to account for the time lag, speed, anonymity and nature of replication inherent in digital formats. To fully investigate the digital record, scholars need a new framework that apprehends the complex density of a multidirectional political discourse that defies traditional time controls.

Using information and linguistic theory we develop and apply a functional, information flow model that illuminates the conceptual relationships and capacities of people to shape their information environment. Actors are defined in terms of their communicative role in idea exchange and the logic of communication is alloyed with political considerations to examine the scopes of action and immersion scenarios that affect communicants.

Our modular and scalable theory offers a way to measure signal fidelity, node activation, and message branching. We define signaling and amplification schemes and effects and explore the benefits and disadvantages of amplification devices for speakers and recipients. We show how individual actors are linked by the micro information streams they receive and transmit. We are therefore able to model exposure conditions of a multiple input, noisy spectrum for citizens and provide a counterpoint to the simple, controlled environment of agenda-setting experiments.

Finally, due to its foundation in information theory, our framework provides a natural platform by which to organize and develop a research program that uses computational linguistics and data mining techniques.

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28

Herman, Jennifer Linda. "Effecting Science in Affective Places: The Rhetoric of Science in American Science and Technology Centers." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1396961008.

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29

Larsson, Johannes. "Streamline Communications in Radiology." Thesis, Linköping University, Department of Computer and Information Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17421.

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The background to the study was Unified Communications (UC), defined as Communications integrated to optimize business processes. A case study design is used to develop a LoFi-prototype. The prototype investigateswhat components an integrated communication solution should provide,for the people in radiology. The design was inspired by consumer products likeSkype. In these consumer products were functionality and look studied. The reason for integrate it into Sectra MEI, was that Sectra believed the system’s features could be even more useful, when used together with a communication solution. The prototype is tested on users (usability tested). To bundle the growing pile of requirements in the design process was a requirement specification produced.

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30

Lu, Ying. "Agent-based service discovery in ad-hoc communications environments." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26703.

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Service Discovery allows for the automatic and spontaneous discovery and configuration of network services. It is especially important in ad-hoc environments where the network topology is unpredictable. We propose the use of Agent Technology, an efficient and convenient technology, in our work to shed new light in this area. Our first model takes on a centralized architecture. One agent in the network, the Service Discovery Agent (SDA), assumes the responsibility of maintaining the central service repository. Each service and user has their own agents which we name Service Agents (SAs) and Personal Agents (PAs) respectively. SAs are responsible for registering and deregistering their services with the SDA. Our second discovery model uses a distributed architecture that can operate in a fully dynamic environment. For this we use an existing probabilistic P2P search algorithm as a basis. Discovery is performed on demand using the concepts of the P2P search algorithm. The algorithm is enhanced in many ways so that it is adapted to an ad-hoc environment while still keeping the basic efficient operations. As more searches are performed, devices become more knowledgeable and discovery performance would improve. (Abstract shortened by UMI.)

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31

Asikhan-Berlinguette, Nursel. "Communications service synthesis from informal specifications and sequence diagrams." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/MQ57081.pdf.

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32

Wey, Shou-Jen. "Performance analysis of error control protocols in computer communications /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487681788254348.

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33

Telatar, Ä°brahim Emre. "Multi-access communications with decision feedback decoding." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13237.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.
Includes bibliographical references (leaves 84-85) and index.
by Ä°brahim Emre Telatar.
Ph.D.

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34

Cox, Robert Williams 1979. "Laboratory experiments for a wireless communications course." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87221.

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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (p. 123-124).
by Robert Williams Cox, IV.
M.Eng.

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35

Wilcoxson, Donald C. (Donald Craig). "Phase noise in low-power radio communications." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38178.

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Thesis (Elec. E.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
Includes bibliographical references (leaves 99-101).
by Donald C. Wilcoxson.
Elec.E.

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36

Mohapi, Setumo J. (Setumo James). "Power control for spread spectrum communications systems." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39756.

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37

Welborn, Matthew Lee 1966. "Flexible signal processing algorithms for wireless communications." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86556.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.
Includes bibliographical references (p. 129-132).
by Matthew Lee Welborn.
Ph.D.

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38

Mastin, Alan. "Human-Machine Interface for Tactical Air Traffic Control Communications." UNF Digital Commons, 1990. http://digitalcommons.unf.edu/etd/133.

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This thesis proposes the design for a prototype device that would be used by Air Traffic Controllers in the radar environment to input tactical Air Traffic Control (ATC) instructions to be sent to aircraft via the Mode S digital data link network. The purpose of the device is to reduce the time required to issue instructions and to eliminate misunderstandings that occur when instructions are issued over voice transmission frequencies. The purpose of this thesis was to develop the device in the most ergonomically suited manner based on the air traffic controller's communications requirements. Digital communications systems include both airborne and ground based components. This project was concerned with the development of the ground-based aspect of the communications system.

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39

Corser, George P. "Securing location privacy in vehicular applications and communications." Thesis, Oakland University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10169186.

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Vehicular communications systems may one day save lives, reduce fuel consumption, and advance connectivity, but they may also transmit information which could be deanonymized to obtain personal information. Vehicle location data are of special concern because they could be used maliciously. This dissertation presents a systematic study resulting in novel definitions, metrics and methods for evaluating and applying location privacy preserving protocols specifically in vehicular settings.

Previous work in vehicular network privacy has not thoroughly considered vehicular mobility patterns. Previous work in vehicular network privacy has not solved the problem of collusion between MAC layer and application layer attackers. As defenses against location privacy attacks, previous work has favored the privacy methods of anonymization and obfuscation, but these methods have weaknesses. Spatial-temporal cloaking, for example, requires overhead of trusted third parties, and provides little protection in low vehicle densities especially when applications require frequent precise location data. Little published work has addressed the "location" part of location privacy, the geographical distance of location privacy, focusing instead on the size of the anonymity set. The need for new metrics is indicated.

The present research addresses these issues. In addition to new definitions and metrics, this study develops privacy methods which would (1) accommodate vehicular mobility patterns, (2) defend against collusion by MAC and application layer attackers, (3) produce privacy solutions which depend on cooperation neither by large numbers of other motorists nor by trusted third parties, and (4) function in low vehicle densities, notably during the transition period between system initialization and full saturation, (5) provide protection even when applications require frequent and precise location queries, and (6) provide protection over a geographical range beyond a vehicle's wireless communications range and provide protection over measurable and lengthy spans of time. Finally, it presents a new metric for measuring privacy (KDT), an equation to estimate the safety impact of privacy protocols (SSTE), and three new privacy models, Endpoint Protection Zones (EPZ), Privacy by Decoy (PBD) and Random Rotation of Vehicular Trajectory (RRVT).

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40

Zhang, Rong. "Non-orthogonal random waveform based multiuser communications." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/66594/.

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This thesis is aimed at providing a unified treatment of non-orthogonal random waveform based multiuser communications, commencing from the underlying theory and providing the way to sophisticated applications. In Chapter 2, we introduce the general framework of non-orthogonal random waveform based multiuser communications, where we focus our attention on the fundamental theory behind this topic. We then pay particular attention to three general application aspects, where the principle of non-orthogonal random waveform based multiuser communications may be exploited. These are applied to cellular systems in Chapter 3, to cooperative systems in Chapter 4 and they are combined with a practical Hybrid Automatic Repeat reQuest (HARQ) system in Chapter 5. In the cellular system scenario presented in Chapter 3, we discuss three design tradeoffs ofMulti-Carrier Interleave Division Multiple Access (MC-IDMA) with the aid of EXtrinsic Information Transfer (EXIT) charts. Based on the analysis of IDMA, we generalise the principle of nonorthogonal random waveform based multiuser communications, leading to the so-called Interleaved Random Code Division Multiple Access (IR-CDMA) concept. We also consider an interferencelimited cooperative system in Chapter 4, where we propose a novel Interleaved Random Space Time Code (IR-STC) scheme, which is specifically designed for aMulti-Source Cooperation (MSC) scenario. Furthermore, the network coding concept is also employed, when designing a coded MSC arrangement for the sake of improving the attainable energy efficiency. More specifically, the proposed Physical-layer Algebraic Network Coding (PANC) scheme implicitly inherits the random coding principle applied in a distributed manner. In Chapter 5, we proceed by proposing a novel SuperPosition Coding (SPC) aided multiplexed HARQ scheme for substantially improving the overall end-to-end transmission efficiency. In parallel to presenting our general framework of non-orthogonal random waveform based multiuser communications, we bear inmind that employing a powerfulMulti-User Detector (MUD) for maintaining a near-single-user performance is of high importance. Hence, in Chapter 6 we propose a novel so-called Harmony Search (HS) algorithm for joint iterative channel stimation, data detection and channel decoding. The algorithm proposed can be readily employed to replace all detection algorithms used throughout Chapters 3 to 5, when a high throughput is desired.

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41

Cheng, Raymond (Raymond Y. ). "WhanauSIP : a secure peer-to-peer communications platform." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62637.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 61-63).
This thesis presents a novel mechanism for achieving secure and reliable peer-to-peer communications on the Internet. WhanauSIP merges a Sybil-proof distributed hash table with the session initiation protocol (SIP) to enable instant messaging, audio chat, and video conferencing that is resilient to censoring, eavesdropping, and forgery. Performance and security evaluations performed on the PlanetLab network demonstrate that the majority of resource lookups return within five seconds. These results indicate that WhanauSIP delivers practical performance with respect to call session initialization latency for voice-over-IP, without having to rely on any central servers. Furthermore, the tests demonstrated that lookup performance was minimally affected during a Sybil key-clustering attack, illustrating the network's resilience to malicious adversaries. This thesis delivers three software packages for public use: a general Whanau distributed hash table implementation, a WhanauSIP gateway, and a desktop IM/VoIP client.
by Raymond Cheng.
M.Eng.

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42

Gu, Keren M. Eng Massachusetts Institute of Technology. "Enabling supportive communications in decentralized multi-agent teams." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100597.

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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 33-36).
Supportive communication is an eective collaboration behavior identied in human teams in which team members share information proactively to improve overall team performance. Prior work formulated this objective as the Single-Agent in a Team Decision Problem (SAT-DP) where agents decide whether or not to communicate an unexpected observation during execution time. We extend the SAT-DP denition to include sequential observations, highlighting the need for belief updates of attributed mental models of agents. These updates must be performed effectively and eciently to minimize model divergence and maximize the utility of future communications. In this paper, we present a decision-theoretic solution to the sequential SAT-DP. In our solution, we propose the use of Bayesian plan recognition as one of the methods for reducing divergence in mental models. To achieve computational tractability, we use probabilistic ordered AND/OR trees to compactly represent distributions over possible solutions of hierarchical planning problems. Finally, we evaluate and demonstrate the eectiveness of our proposed approach on decentralized agents collaborating in partially observable environments.
by Keren Gu.
M. Eng.

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43

Erkmen, Baris Ibrahim 1980. "Performance analysis for near-field atmospheric optical communications." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/28469.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.
Includes bibliographical references (p. 143-146).
Establishing, high data rate communication links over short distances via fiber-optic cables may prove costly and time consuming, particularly in urban areas. Through-the-air optical communication systems are a reliable and cost effective alternative for establishing high data rate links when the two terminals have a clear line-of-sight. Bad weather conditions, such as rain, snow or fog, degrade performance severely for such links. However, even in clear weather conditions, local refractive index fluctuations in the atmosphere known as atmospheric turbulence, may drastically impair performance. Most optical links are set up to operate in the far-field power transfer regime, in which diffraction spread is the dominant effect on the beam. Therefore, a very small portion of the beam is captured at the receiver, resulting in very weak power coupling between the transmitter and the receiver. However, it is also possible to establish geometries such that the link operates in the near-field regime, where, in absence of turbulence, it is possible to focus the beam onto the receiver with almost perfect power coupling. Work on performance of near-field atmospheric optical communication systems is scarce in existing literature, perhaps due to increased complexity in prescribed models. In this thesis, we analyze error probabilities of binary optical communication links operating in the near-field regime, utilizing on-off keying (OOK) or pulse position modulation (PPM) signaling techniques. We also obtain bounds on the capacity of a single-input, single-output (SISO) atmospheric optical communication link with a coherent-detection receiver operating in the near field.
by Baris Ibrahim Erkmen.
M.Eng.

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44

Wu, Cynara C. "Dynamic resource allocation in CDMA cellular communications systems." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9332.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.
Includes bibliographical references (p. 115-117).
Efficient resource utilization is the primary problem in cellular communication systems. In this thesis, we combine the main resource issues for CDMA systems, admission control and power control, in a single framework. The framework uses a formulation that is general enough to incorporate all significant parameters of a system, yet tractable to compute. We formulate the resource allocation problem as a Markov decision process. Due to the enormous size of the state space, applying the traditional solution technique, dynamic programming, is impractical. We therefore consider approximation techniques. As a first step towards simplification, we divide the problem into two subproblems: optimal admission control with heuristic power control and optimal power control with heuristic admission control. We formulate the problem of optimal admission control as a Markov decision process and consider several approximate dynamic programming techniques. We apply these techniques to a simulated system and obtain results that improve significantly upon two commonly used policies, the greedy policy and the reservation policy. We then consider the minimization of the total power transmitted over given discrete sets of available power levels subject to maintaining an acceptable signal quality for each mobile. We develop sequential and distributed iterative algorithms for solving a more general version of this integer programming problem and show that they find the optimal solution in a finite number of iterations which is polynomial in the number of power levels and the number of mobiles.
by Cynara C. Wu.
Ph.D.

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45

Bellei, Francesco. "Superconducting nanowire single photon detectors for infrared communications." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/109008.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 113-120).
The ever-increasing data sharing demands of modern technologies forces scientists to adopt new methods that can surpass the approaching limits of classical physics. Quantum optical communications and information, based on single-photon detectors offer the most promising possibility to reach new levels of data rate and communication security. Superconducting nanowire single-photon detectors (SNSPDs) have already been used in the past to demonstrate new protocols of quantum key distribution and are currently the best single-photon detection technology to enable quantum optical communication. With the goal of creating a global quantum communication network, both optical fiber and free-space optical communication technologies have been explored. In addition, the scientific community started pursuing smaller and cheaper cryogenic solutions to enable the use of SNSPDs on a large scale. In this thesis, I describe the design and development of a cryogenic SNSPD receivers in free-space and optical-fiber configurations for 1550-nm-wavelength. The first configuration was created with the goal of enabling optical communication in the mid-IR. I present future steps to achieve this goal. The second configuration was designed to enable a compact and scalable integration of multiple SNSPD channels in the same system. Our approach has the potential of enabling SNSPD systems with more than 64 channels.
by Francesco Bellei.
Ph. D.

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46

Yates, Roy D. "Methods of multiple access communications with energy detectors." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15085.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaf 31.
by Roy D. Yates.
M.S.

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47

Horkley, Benjamin William. "Optical communications with a Geiger mode APD array." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106009.

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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 47-48).
In this thesis, I evaluated the theoretical and practical performance of a Geiger mode avalanche photodiode (GM-APD, or Geiger mode APD) array for use in optical communications systems. I designed and implemented a test pattern generator, capable of producing waveforms with OOK and PPM modulations at a variety of symbol rates and duty cycles. Using this pattern generator, I tested the receiver properties over a wide range of data rates and illumination levels, and was able to demonstrate the capability for error-free communications in both modulation formats, up to 78.8 Mbps at a sensitivity of 1.8 photons per bit for OOK, and 34.9 Mbps at 2 photons per bit for PPM.
by Benjamin William Horkley.
M. Eng.

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48

Cox, Criston W. "Optimizing bandwidth of tactical communications systems." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FCox.pdf.

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Thesis (M.S. in Systems Technology (Joint Command, Control, Communications, Computers and Intelligence (JC4I))--Naval Postgraduate School, June 2005.
Thesis Advisor(s): William Kemple, John Osmundson. Includes bibliographical references (p. 59-60). Also available online.

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49

Manco, Vega Alejandra. "Early career researchers and PhD students from the social sciences use of Social Networking Sites (SNS) for science communication: an affordances approach." Thesis, Uppsala universitet, Institutionen för informatik och media, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-332028.

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This research aims to understand the different practices and strategies early career researchers and PhD students from the social sciences have in Social Networking Sites (SNSs) for science communication in one particular country: Brazil. Following this purpose, the central research question is which are the motives and rationale of the researchers for using social networking sites for science communication. Two sub-questions arise from this general research question: How do practices and strategies relate to the academic system of this country? And How do the traditional science communication practices translate into the use of Social Networking Sites (SNS)? This research is empirically oriented building up on case studies in Brazil. This study makes use of the adaptation that Van Dijck (2013) made of the Actor-Network Theory (ANT) and the review of affordances of social media platforms (Bucher & Helmond, 2016) to apply it to the study of social media as the theoretical approach. The methodological approach of this research is qualitative, using both interviews and netnography as research methods. The primary motivations for using different Social Networking Sites are all related to connectivity: communication with peers, to the public and research subjects, updating themselves about their research issue, dissemination of research, availability of papers, self-branding and participation in interest groups are the most mentioned. These motivations translate into cross-posting practices and integrated communication strategies -combining online and offline elements- on the different Social Networking Sites. These motivations translate into perceived affordances all related to social affordances, therefore, social capital processes: availability, scalability, visibility and multimediality. The academic system of the country has remained unchanged as it privileges traditional scholarly academic formats; therefore, early career researchers and PhD students from the social sciences only use the different Social Networking Sites (SNS) as a side aid but not as a primary means of communication. Social media is underused as a means of public science communication, even though these platforms offer a lot of advantages for pursuing such issue. Traditional science communication practices translate into the use of Social Networking Sites (SNSs). The most important issue that came out in this report was the fact that social affordances provided by Social Networking (SNSs) are still required to be endorsed by real life meeting to start further collaboration and the fact that English is the preferred language for such issues.

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50

Morford, Gary D. "Cooperative Science in a Computer-Mediated Communications Environment Effects on Developing the Integrated Science Process Skills of Secondary Students In Pennsylvania." NSUWorks, 1992. http://nsuworks.nova.edu/gscis_etd/735.

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This study investigated the possible correlation between Advanced Placement Computer Science Examination scores and secondary teacher certification in computer science, prompted by the low scores for South Carolina students and the lack of such certification in South Carolina. A survey was sent to the chief education official in each of the United States of America, the District of Columbia, U.S. territories, the Department of Defense Dependent Schools, and selected technically oriented foreign countries, to determine the current status of the recognition of computer science as a certification area. Scores for the 1990 Advanced Placement (AP) Computer Science Examinations were secured from the College Board for statistical analysis. Of the agencies sent surveys, 52 had AP computer science test scores and became the agencies used for statistical analysis. These agencies included the 50 United States, the District of Columbia, and Puerto Rico. Both the average test score and the percentage of students passing each of the two AP Computer Science Examinations were arranged into descending order. The number of certifying agencies were counted in each quartile. The number of expected and observed certifying agencies were analyzed using a chi square test for two-way classification to determine if the recognition of computer science as a certification field correlated with student success, as measured by average score and percent passing . The results of the survey showed that the number of agencies offering computer science certification had markedly increased since previous studies were undertaken in 1983 and 1986. Beginning in 1991, 24 of the 50 states will offer such certification, while only five offered computer science certification in 1983 and 11 offered such in 1985. In addition, the District of Columbia, Department of Defense Dependent Schools, and Guam have some type of computer science certification. Results for foreign agencies replies are presented for information, since few participate in the Advanced Placement Program. The chi-square analysis failed to establish a correlation between the adoption of computer science certification and student success on either of the Advanced Placement Computer Science Examinations. While no correlation was found between teacher certification and student success, an apparent trend of more and more states recognizing computer science as an area of teacher certification was verified. Further investigation into student success on the Advanced Placement examinations should be continued, as should the continuation of the investigation of computer science certification.

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Dissertations / Theses on the topic 'Science communications'

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