Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 87-88).

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Guosheng Liu, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed June 8, 2006). Document formatted into pages; contains xi, 85 pages. Includes bibliographical references.

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Jane A. Boles. Includes bibliographical references (leaves 59-68).

Thèse de doctorat--droit--Poitiers, 1998. / Bibliogr. p. 1863-2183.

Texte remanié de: Akademisk avhandling--Juridiska fakulteten--Stockholm universität. / Bibliogr. p. [201]-219. Index.

The increasing demand for broadband multimedia services and their extension to mobiles has spurred provision via satellites. This is because satellite systems can provide a truly global coverage that cannot be economically realised by either fixed wireline systems or terrestrial mobile systems. Most of next generation satellite systems proposed, such as Astrolink, SPACEWAY and SkyBridge, consider using ATM or ATM based technology over satellite to provide broadband services requiring mobility and higher bandwidth. This thesis therefore concerns future broadband satellite networks that use on-board processing and intersatellite links to extend the terrestrial ATM provision to worldwide satellite systems. This thesis discusses the air interface connection management and call handling schemes for integrated mobile/fixed ATM-satellite networks. The prime aim is to research an integrated solution that provides effective radio connection management and mobility support whilst maintaining the required QoS at both user terminals and gateway earth stations. We target at minimising the difference in performance between terrestrial ATM and ATM over satellite and providing mobility extension to the ATM protocols, whilst maintaining a high satellite channel efficiency and keeping as little as possible signalling modifications. In this thesis, an efficient radio connection management scheme, which is designed for a QoS-provisioning transport of ATM traffic over satellite links, and a mobility-enhanced signalling protocol scheme for mobile ATM-satellite networks are proposed. Another large proportion of this thesis is devoted to the optimisations of multiple access and logic link control because these are the major factors that effecting the performance within ATM- satellite integrated systems. As a result, a semi-permanent signalling protocol, a reliability- dependent Selective Repeat Automatic Repeat reQuest (SR ARQ) and an adaptive timer SR ARQ are proposed. In addition to the proposed connection management scheme, a reservation meta-signalling for setting up signalling connections at the user-network radio interface and a mobility-enhanced call handling protocol derived from Q.2931 are proposed. Call control functions such as call routing, location update, paging, handover and authentication are discussed as well. The proposed signalling protocol architecture provides a protocol reference model for ATM-satellite integrated systems. The verification and demonstration of the advantages of the semi-permanent signalling protocol, which offers a new method to improve the system channel efficiency on signalling connections, have been achieved. The proposed reliability-dependent SR ARQ protocol provides a novel approach to optimise the transmission throughput to support a variety of traffic types with different QoS requirements in ATM-satellite systems. The proposed connection management scheme effectively manages the air interface connections for ATM services through diversifying connection types, establishing QoS-based connections and deploying an efficient connection mapping and control scheme. The proposed radio connection management scheme together with the optimised Multiple Access Control (MAC) and ARQ provides a framework of interworking protocols for ATM over satellites. It can also find application in other similar systems that involve the integration of terrestrial protocols and mobile satellites. The research work that has been accomplished herein provides a solution and guidance to the design of signalling protocols for mobile satellite systems to implement ATM technology or indeed other future protocols.

New payload concepts of low cost earth stations for future mobile satellite communications can only be realised by using dedicated on-board processing satellites. The satellite uplink and downlink are optimised by the use of FDMA/SCPC for uplink and TDM on the down link. This scheme allows mobile transmitters to transmit a narrow band, low power signal, resulting in smaller dishes and HPAs with lower output power. On the uplink, there are hundreds of FDM channels to be demodulated on-board. The most promising approach is the use of all-digital multicarrier demodulators (MCDs), where analogue and digital hardware are efficiently shared amongst the channels and digital signal processing is used at an early stage to take advantage of VLSI technology. A MCD consists of a channeliser for separation of FDM channels followed by individual demodulators for each channel. The major research areas in MCD's are efficient implementation of channelisers and the optimal demodulation algorithms for the demodulator. This thesis is focused on the demodulator part of an MCD using OQPSK modulation which haye received attention recently due to its spectral advantages in non-linear mobile satellite channels. Most of the research carried out on the OQPSK modulation has been addressed to its spectral performance under satellite channel non-linearities, but little attention has been paid to efficient receiver designs. The most important requirements of the demodulator in a mobile environment is fast acquisition with minimum overhead. This over-head includes long preambles in data frames to aid the acquisition of the carrier and the symbol timing recovery loops. In this thesis, research on preambleless all-digital demodulators for OQPSK has been carried out. The performance of the most suitable OQPSK synchronisation algorithms have been evaluated using extensive computer simulations. These algorithms have been selected after a comprehensive survey of digital synchronisation techniques. It is shown how these algorithms are related to the maximum likelihood (ML) principle and these algorithms are classified according to their technique of parameter extraction from the likelihood function. The synchronisation problems associated with OQPSK are pointed out with possible solutions. On the basis of the performance results of individual synchronisers, various demodulation algorithms for OQPSK have been developed for fixed, mobile and deep space applications. The DSP implementation of the all- digital OQPSK demodulator developed for the MCD for mobile applications is described in detail and its performance compared with simulation results.

Mobile Satellite Communication Systems are the best, and probably the only solution to a full 'global communication coverage'. Despite the intense scrutiny and inherent difficulties in gaining acceptance by the telecommunications market and the recent switch back towards GEO satellites, mobile satellite systems in non-geostationary LEO (500-2000km) and MEO (10000-12000km) constellations still remain an attractive solution in an integrated satellite/terrestrial scenario as they offer lower delays and lower power requirements than GEO satellites (35800km). Since Quality of Service (QoS) and service availability are major subscriber concerns, the investigation of factors which influence them are of central importance to the design of such systems. In non-GEO mobile satellite systems both the QoS and the service availability are very much dependant on the changing dynamics of the constellation and on the time varying nature of the propagation environment. Motivated by the above issues, we present, analyse and evaluate the coverage and availability of first generation constellation proposals in terms of LOS and bit-error-rate (QoS) requirements. Handover management is also identified as an important issue affecting the QoS and therefore handover strategies and mechanisms for various satellite constellations are presented and analysed. Based on the statistical but predefined nature of the constellation dynamics as well as the influence of the propagation channel and its dependence on the constellation design we propose two new channel adaptive handover algorithms in an effort to reduce the handover signalling whilst maximising at the same time the QoS as perceived by the user in terms of reduced call dropping rate for a typical circuit mode telephone call. Finally, as the current trend of the telecommunication services is towards the provision of packet oriented services, we focus the final part of this study on the performance investigation, in terms of throughput versus delay characteristics, on the provision of GPRS-like services over mobile satellite systems and compare GEO and non-GEO delivery. It is concluded, based on the MAC protocol proposed in the last chapter, that depending on the type of traffic and on the network load, the LEO approach doesn't always give superior performance in terms of delay characteristics to that of a MEO. The results and findings presented in this thesis can be used as a reference for optimising and designing future mobile satellite systems. Key words: Availability, QoS, handover, MAC protocols, satellite channel.

Unaltered peridotite xenoliths are broadly representative of the lithospheric mantle in both oceanic and continental domains. These peridotites are mainly lherzolites and harzburgites. Other rock types such as dunites, wehrlites and pyroxenites are generally not volumetrically significant. The respective contributions of rock-forming minerals to induced and remanent magnetization in these rocks are currently poorly constrained. This information can be used to assess the significance of long-wavelength magnetic anomalies. It can also provide insights, as an alternate approach to the spinel-olivine-pyroxene oxybarometer, into several important petrologic parameters of the lithospheric mantle including fO2. Forty-nine representative, uncontaminated and non-serpentinized xenoliths have been magnetically investigated. These specimens display contrasting remanent magnetic properties (NRM, Mr, Ms) depending on their tectonic settings, specifically oceanic hot-spot, continental mantle plume, island arc, and craton. The main paramagnetic silicates (olivine, clinopyroxene, orthopyroxene, etc...) typically account for most of the peridotite magnetic properties. The low-field bulk magnetic susceptibility of pristine, unaltered mantle xenoliths is ≈ 500 ± 60 x 10-6 [SI] and displays limited variability. The total contribution of paramagnetic silicates to magnetic susceptibility (Kpara-silicates) can be determined from the high-field slope of a saturated hysteresis experiment. Kpara-silicates can also be calculated by adding the respective contributions of individual silicates based on their modes, chemical composition, and the Bohr magneton numbers of individual cations. Silicates account for between 56 and 97% (average ≈ 85%) of the magnetic susceptibility depending on rock composition. When present, the contribution of chrome spinel, which is paramagnetic in the absence of late-stage exsolution products, remains around 1%. Plagioclase-, spinel- and garnet-lherzolites share similar low-field magnetic properties. The remaining contribution to magnetic susceptibility arises from variable amounts of primary magnetite (and pyrrhotite to a minor extent). These mineral phases, although present in tens to hundreds of ppm only, contribute significantly to the rock magnetic properties because they have large intrinsic magnetic susceptibilities (≈ 1 to 4 [SI] for magnetite). Stoichiometric magnetite has been identified as microscopic exsolutions in the lattice of olivine and accounts for 2 to 43% (average ≈ 8%) of the magnetic susceptibility. Whether these pseudo-single domain magnetite grains are in equilibrium with other rock-forming minerals or not is still being investigated. Pyrrhotite (up to 600 ppm in some rare specimens), although detectable in low-temperature magnetic experiments, does not significantly contribute to magnetic susceptibility. The contribution of ferromagnetic minerals, such as magnetite and pyrrhotite, to remanent magnetization (Mr) is significant and varies greatly (over 250x between specimens) with tectonic setting. The fact that all specimens contain primary magnetite suggests that these assemblages equilibrated at least at or above the wüstite-magnetite (WM) oxygen buffer and near the fayalite-magnetite-quartz (FMQ) oxygen buffer. The amount of magnetite present in the mantle peridotite assemblage seems to correlate with tectonic setting and may be linked to fO2 in the mantle. The timing of magnetite exsolution in olivine is still poorly understood and may depend on degree of partial melting, rate of cooling to ambient lithospheric temperature, or mantle metasomatic processes due to introduction of hydrous fluids.

This thesis provides an extended analysis and review of the television policies of the UK Conservative administrations of Margaret Thatcher and John Major from 1979 to 1997 and examines the causes, coherence and consequences of those policies. In particular, it identifies the potential forces for change in UK television policy from the late seventies: notably, international changes in the economic, social and cultural, and technological environment of the industry; and the political changes in the UK introduced by the new Conservative administrations, generally known as `Thatcherism'. The thesis analyses the specific strengths of the UK television system established by the 1970s, and reviews the criticisms made of that system in the years before 1979. It then assesses the major developments in television policy instituted by the Thatcher and Major administrations: the establishment of Channel 4; their policies on the new technologies of satellite and broadband cable; the impact of the Committee chaired by Alan Peacock on the Financing of the BBC; the reform of ITV; their policies for the renewal of the BBC charter in the 1990s; and their policies on digitalisation and multimedia. Particular attention is paid to the changes that these policies produced in the UK television industry, and the lack of overall coherence of the policies. The thesis argues that the changes were significant but that they were only partial, and that, while pursuing a general goal of marketisation, the policies were incoherent in many of their specifics. This incoherence stemmed partly from resistance by established institutions within the industry, and partly from internal contradictions within the Tories' overall free-market project. The thesis concludes with an examination of the light that Tory television policy during this period sheds on the wider political debate on `Thatcherism' and the international context of UK television policy during the same period.