Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 167-172). Also available on the Internet.

Thesis (M.A. in International Security and Civil-Military Relations)--Naval Postgraduate School, June 2003. / Thesis advisor(s): Donald Abenheim, Douglas Porch. Includes bibliographical references (p. 59-60). Also available online.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 167-172). Also available on the Internet.

The increasing traffic demand from the use of 3G/4G, streaming, and other broadband wireless services exposes existing bottlenecks in the communications infrastructure and the coordination between the wireless network and its wired counterpart. While wireless systems are constantly evolving to newer generations and higher capacities, their supporting wired networks urgently require advancements in both architecture design and enabling technologies. New optical access systems specifically tailored for the unique natures of various wireless standards are investigated. This dissertation presents the design and experimental verification of high-capacity optical-wireless communication systems using advanced electrical and optical technologies. Technologies such as high level modulation and multiple-input and multiple-output (MIMO) to increase the spectral efficiency is approaching the Shannon limit. New frequency bands with larger bandwidth are to be explored; for example, millimetre wave (mm-wave) spectrum range (30-300 GHz), especially the license-free spectrum located in 60 GHz. Although fiber-optic systems excel in the high-bandwidth core network, as bandwidth demand increases, more and more progress has been made towards the usage of fiber in the last mile. Radio-over-Fiber (RoF) technology has been proposed as a cost-effective optical access solution to support high-speed wireless communications, especially at the mm-wave band. Signal processing and coordination are centralized at the central office (CO), making the system economical and simple to build, operate, and maintain. Moreover, RoF systems are capable of delivering radio signals with different frequencies and protocols simultaneously. Therefore, the advantage of integrated fiber wireless systems leads to the first research topic of this dissertation: multi-band multi-service RoF systems. With an emphasis on the uniformity of the RoF platform that accommodates both legacy wireless services and advanced mm-wave services, the first part of the dissertation presents two schemes - analog all-band RoF and band-mapped 60-GHz RoF - to cover distinct application scenarios. In the all-band RoF access architecture, lower RF signals, such as Wi-Fi and cellular signals, and 60-GHz signal are transmitted at their original carrier frequencies for both indoor and outdoor coverages. On the other hand, the band-mapped mm-wave RoF scheme, fully utilizing the wide 7-GHz bandwidth at 60 GHz, delivers multiple converged high-speed services only through 60-GHz wireless link, which is especially suited for in-building broadband wireless access. The experimental verification of an all-band RoF system featuring relaxed component requirement is introduced, followed by a real-time multi-service demonstration in the proposed band-mapped 60-GHz RoF system. This dissertation also presents the design, analysis, and experimental demonstration of next-generation high-capacity cellular networks to keep up with the ever-growing bandwidth demand and performance requirements. New mobile backhaul (MBH) architectures based on orthogonal frequency division multiple access (OFDMA) are proposed along with a simple and low-latency clock distribution and recovery scheme. The transmission of OFDMA signals in the dense wavelength division multiplexing (DWDM) network with flexible clock rates and DSP-free clock recovery is implemented. Also, a spectrally-efficient, low-complexity clock distribution and recovery scheme for OFDMA-based MBH in coherent ultra-dense WDM (UDWDM) system is demonstrated. Finally, mobile fronthaul (MFH) architectures based on subcarrier multiplexing (SCM) technology, which significantly reduces the requirements on both the number of wavelengths per cell site and the optical bandwidth of the optical transceivers, are systematically investigated. Additionally, two upstream schemes, tailored for the uplink (UL), are introduced to maintain low complexity, and more importantly, to achieve high spectral efficiency by wavelength sharing. Therefore, Internet-access-oriented optical-wireless systems using Wi-Fi and other emerging mm-wave technologies are developed along with the optical fronthaul and backhaul for cellular networks in this dissertation. Moreover, with the proposed techniques, heterogeneous networks can be seamlessly provided even with different services, radio nodes, and performance requirements.

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / In the past several years there has been a good amount of effort expended in migrating telemetry streams to IP-based infrastructure, especially in the area of ground-based transport. This has yielded a number of benefits, from leveraging the properties of IP transport to enable multicast transport, to the integration of the wide number of COTS equipment that also is IP-based, such as digital video encoder/decoders into range networks. This paper will provide a model for identifying areas to accelerate the integration of IP-based assets into the range infrastructure at the application level. In particular the integration of metadata between the telemetry and video application interfaces will be explored.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The expected efficiency of network-based telemetry systems vs. the tried and true PCM-based approaches is a debated topic. This paper chooses to use a lighthearted voice to pull the two sides of the "war" to a table of negotiation based on metrics. Ultimately, focusing on metrics that truly define efficiency is the key to understanding the varying points of view. A table of these metrics along with the "why and when" criteria for their use is presented based on historic mathematical information theory, true flight test data requirements, and lab analysis. With these metrics, the negotiation and reasonable compromises in the war may become clear. In other words, this paper attempts to provide a methodology that can be used by the community to aid in choosing the appropriate (or good enough) technologies for current and future telemetry testing demands.

Issues around Quality of Service (QoS) and security for Voice over IP (VoIP) have been extensively investigated separately, due to the great attention this technology currently attracts. The specific problem this work addresses centres upon the selection of optimal parameters for QoS and security for VoIP streams integrating both network impairments and user perception metrics into a novel empirically-driven approach. Specifically, the simulation model seeks the optimal parameters in terms of variable VoIP payloads, iterative block ciphers, codecs and authentication mechanisms to be used, so that optimum tradeoff between a set of conflicting factors is achieved. The model employs the widely used Transmission Rating Factor, R, as the methodology to predict and measure the perceived QoS based on current transmission and network impairments. The R factor is then used to map perceived QoS to the corresponding Mean Opinion Score value, which gives the average estimation of perceived voice quality (Quality of Experience). Furthermore, a genetic algorithm (GA) has been developed that uses the output from the simulation model as an input into an offline optimisation routine that simultaneously maximises the VoIP call volumes and the Level of Encryption (LoE) per call basis, without degrading the perceived quality of service under a specific threshold as dictated by the R factor. The solutions reflect the optimum combination of parameters for each codec used and due to the small size of the search space the actual speed of GA has been validated against an exhaustive search algorithm. The results extracted from this study demonstrate that under strict and pre-defined parameters the default payload size supported by the codecs is not the optimal selection in terms of call volume maximisation and perceived QoS when encryption is applied.

The disproportionate representation of minority students in special education programs has been a problem for over forty years. Factors contributing to minority overrepresentation include the lack of primary prevention, inappropriate language and educational assessment, over-referral of minority students for suspected learning difficulties, duration of enrollment in language support services [i.e. English as a Second Language instruction (ESL)], and lack of cultural and linguistic knowledge by K-12 teachers, specialists, and administrators. The goal of the investigator was to determine pertinent placement factors used by Multidisciplinary Educational Team (MET) members when deciding whether or not to place Latino English Language Learner (ELL) students in special education for a suspected specific learning disability (SLD). Identification of such factors may elucidate why some ELL students are inappropriately placed in special education for a SLD while others who need services are not. The investigator also willdetermine the extent special education eligibility determination was based on standardized achievement test scores, Intelligence Quotient (IQ) test scores, IQ-achievement discrepancy criteria, and qualitative data such as MET report data.

In this study, Gwen Gray Schwartz argues that students exhibit academic identities that do not always match their instructors' expectations for them and assumptions about them, which creates problems when second language writers enter mainstream composition classes. Using ethnographic methods, she studied three Vietnamese immigrant students from Generation 1.5 who placed into mainstream composition at a large university in the Southwest and found that while each student struggled in some ways to meet the expectations of mainstream composition, their academic identities and notions of success played a large role in how they engaged in or disassociated from the class activities and assignments. Schwartz analyzed the students' writing, and through extensive conversations with them and their mainstream composition instructors discovered that Generation 1.5 students who cross over into mainstream classes have academic identities that are complicated by their status as cross-over students--they juggle multiple languages, cultures, and school systems, all while writing in English while continuing to learn English. And while mainstream instructors do not know how to meet these students' needs, their numbers are increasing steadily across the country. Schwartz begins by complicating the term "Generation 1.5" and "ESL student" and suggests a new term, "cross-over student," to describe those students in Generation 1.5 who place into mainstream composition. Then she describes the term "academic identity" as a lens through which to examine these students' experiences in mainstream composition and their notions of success, which often are quite different from their mainstream instructors'. After extensive analysis of each student's writing, she offers solutions to the placement dilemma this group presents and provides concrete ways for mainstream instructors to better meet the needs of this student population.

Voice over IP technology (VoIP) has recently gained popularity among consumers. Many popular VoIP services exist only as software for PCs. The need of taking such services out of the PC, into a stand-alone device has been discovered, and this thesis work deals with the development of such a device. The thesis work is done for Häger Scandinavia AB, a Swedish telephone manufacturer. This thesis work covers the design of a complete prototype of a table-top VoIP telephone running an embedded Linux Operating system. Design areas include product development, hardware design and software design.The result is a working prototype with hardware and corresponding Linux device drivers. The prototype can host a Linux application adapted to it. Conclusions are that the first hardware version has worked well and that using an open-source operating system is very useful. Further work consists of implementing a complete telephony software application in the system, evaluation of system requirements and adapting the prototype for a commercial design.