M. Tech. Electrical engineering. / Discusses the interference and bandwidth adjusted ETX routing metric uses a logical interference model that refers to the interference arising from the Carrier Sensing Multiple Access with Collision Avoidance (CSMA-CA) based Medium Access Control. This approach of capturing inter-flow is complex and more restrictive. In this dissertation, a more realistic and less restrictive approach based on the information available at the physical layer (signal strength) is used to capture the interference.In contrast to the logical interference model, this has the excellent advantage of measuring the parameters using online data traffic. The question is whether actual capacity improvements can be achieved by considering the physical interference model.

UWB communication is an attractive technology that has the potential to provide low-power, low-complexity, and high-speed communications in short range links. One of the main challenges of the UWB communications is the highly frequency-selective channel, which induces hundreds of overlapped copies of the transmitted pulse with different delays and amplitudes. To collect the energy of these multipath components, coherent Rake receivers are proposed, but suffer from high implementation and computational costs on channel estimation. To avoid the stringent channel estimation, several noncoherent receivers, including energy detector (ED) and transmitted reference (TR), are proposed at the cost of degraded performance. In addition, when taking into account practical issues of UWB communications, e.g., non-Gaussian impulsive noise, non-ideal antennas, and limited, significant performance degradation may be introduced by noncoherent receivers. In this dissertation, we will present low-complexity, high-performance, noncoherent receiver designs for UWB communications that i) avoid the stringent channel estimation; ii) lower the computational complexity of the existing receivers with the aid of advanced digital signal processing techniques; and iii) improve the error performance of the noncoherent receivers by accommodating practical imperfections. First, we propose three multi-symbol detectors (MSDs) for multi-symbol different detection (MSDD), which has recently caught attention in UWB communications because of its high performance without requiring explicit channel estimation. To alleviate the non-deterministic polynomial hardness (NP-hard) of MSDD, we analyze the statistical model of MSDD and propose an iterative MSD and two MSDs based on relaxation technique with near-optimal performance and low complexity. Moreover, the error performance of MSDs is further enhanced by exploiting joint soft-input soft-output MSDD and forward error correction codes. Next, we consider the non-Gaussian noise in the presence of multi-access interference, which is impulsive when the number of active users is small. To mitigate the impulsive noise effect, in this dissertation, we propose new differential UWB receivers based on the generalized Gaussian distribution and Laplace distribution and achieve better error performance. Another main issue of UWB communications is the limited radio coverage. To extend the coverage and improve the performance of UWB systems, we focus on a novel differentially encoded decode-and-forward (DF) non-cooperative relaying scheme. Putting emphasis on the general case of multi-hop relaying, we illustrate a novel algorithm for the joint power allocation and path selection (JPAPS), minimizing an approximate of the overall bit error rate (BER). A simplified scheme is also presented, which reduces the complexity to O(N²) and achieves a negligible performance loss. Finally, we concentrate on code-multiplexing (CM) systems, which have recently drawn attention mainly because they enable noncoherent detection without requiring either a delay component, as in TR, or an analog carrier, as in frequency-shifted reference. In this dissertation, we propose a generalized code-multiplexing (GCM) system based on the formulation of a constrained mixed-integer optimization problem. The GCM extends the concept of existing CM while retaining their simple receiver structure, even offering better BER performance and a higher data rate in the sense that more data symbols can be embedded in each transmitted block. Moreover, the impacts of non-ideal antennas on the GCM systems are investigated given some practical antenna measurement data and IEEE 802.15.4a channel environments.

The main purpose of this research study was to investigate the perceived economic implications that broadband Internet has made on three small Kentucky cities. Perceptions were chosen to be studied, because it appears that perceptions, and not economic indicators, determined the economic viability of each Kentucky city that was researched.This study examined the perceptions of the association of broadband Internet to economic growth through a single-case study approach. Data were collected through multiple, semi-structured interviews with the city's municipal utility, economic development and workforce development sectors. Results from each city were then analyzed by coding and placing the data into themes that emerged from each city.One common theme that appeared throughout small cities in Kentucky was minimal collaboration between the different sectors (broadband Internet provider, Economic Development, and Workforce Development). Closely associated with this theme was a lack of communications between these same sectors in some of the cities. Finally, there was a lack of racial diversity within each city that discouraged innovative ideas and methods.Recommendations included using predictive analysis to plan and track economic development modeling and continue to develop the businesses and industries that are already established, instead of courting new business. Additional recommendations involve the development of a partnership between the municipal utility and private broadband Internet carriers, a relationship between the municipal utility and the rural cooperative, and establishing a technology committee that would include all broadband Internet providers, a economic development representative, a Workforce Development Representative, a city government representative, a county government representative, and a local small business representative. / Department of Educational Studies

Thesis (M. Eng.), Memorial University of Newfoundland, 1998. / Bibliography: leaves 107-112.

Thesis (MScEng)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: This thesis presents a thorough study of the printed sinuous antenna and its characterisation as a feed for re ector antenna applications. Two di erent techniques are used in this study, namely a parametric study and an e cient surrogate based optimisation strategy. A planar sinuous antenna over a re ecting ground plane, with no absorber lining, is designed following a parameter study from which e ective design guidelines are derived. The designed prototype displays a bandwidth ratio of more than 3 : 1 from 1:9􀀀6:2 GHz, at a measured return loss of 10 dB, representing a signi cant improvement over the octave band previously achieved with a similar antenna. An optimisation based approach is followed in formally investigating a conical sinuous antenna over a re ecting ground plane. An e cient surrogate based optimisation strategy, in which the antenna's response is approximated by a Kriging model, is used. The search for optimal design parameters as well as improvements in the accuracy of the Kriging model is accomplished by using expected improvement as the in ll sampling criterion. The antenna is optimised for return loss, aperture e ciency for a prime-focus paraboloid re ector as well as cross-polarisation and results from the optimisation are used to derive e ective design guidelines and performance limitations. The investigations are conducted for the 2 􀀀 6 GHz band and the obtained results can be easily applied for designs with wider bandwidths. Simulation results reveal improved return loss, aperture e ciency and cross-polarisation performances compared to what has previously been reported for this antenna. / AFRIKAANSE OPSOMMING: Hierdie tesis bied 'n deeglike studie van die gedrukte stroombaanbord sinuous antenna, sowel as die karakterisering daarvan as voer vir re ektor antenna toepassings. Twee verskillende tegnieke word gebruik, naamlik 'n parametriese studie en 'n surrogaat-gebaseerde optimering strategie. E ektiewe doeleindes vir die ontwerp is van 'n parameter studie afgelei, waarvolgends 'n planêre sinuous antenna met 'n weerkaatsingsgrondvlak ontwerp is sonder enige absorberende materiale. Die prototipe vertoon beter as 'n 3 : 1 bandwydte van 1:9 GHz tot 6:2 GHz teen 'n gemete weerkaatsingskoë siënt van beter as 􀀀10 dB, wat dui op 'n aansienlike verbetering teenoor die oktaaf bandwydte wat voorheen met 'n soorgelyke antenna bereik is. 'n Optimering-gebaseerde benadering is gebruik om ondersoek in te stel in die gebruik van 'n koniese sinuous antenna met 'n weerkaatsingsgrondvlak. 'n Doeltre ende surrogaat-gebaseerde optimeering strategie is gebruik, waar die antenna se weergawe deur 'n Kriging model benader word. Die verwagte verbetering is gebruik as maatstaf in die soektog vir optimale ontwerpsparameters, sowel as om die akkuraatheid van die Kriging model te verbeter. Die antenna is geoptimeer vir sy weerkaatsingskoë siënt, stralingsvlak e ektiwiteit for 'n paraboloïed antenna sowel as kruispolarisasie. Resultate van die optimering is gebruik om e ektiewe riglyne vir die ontwerp en grense vir die werkverrigting op te stel. Die antenna is ondersoek vir die 2 tot 6 GHz frekwensieband en die resultate wat verkry is kan maklik op ontwerpe met selfs wyer bandwydtes toegepas word. Simulasie resultate dui op 'n verbetering in weerkaatsingskoë siënt, stralingsvlak e ektiwiteit en kruispolarisasie in vergelyking met wat berig is vir hierdie antenna.

Orientador: Paulo Sérgio Fracalanza / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Economia / Made available in DSpace on 2018-08-22T00:39:45Z (GMT). No. of bitstreams: 1 Rauen_CristianeVianna_D.pdf: 2378412 bytes, checksum: 8ef146191d858a3d498ae7da6864954d (MD5) Previous issue date: 2013 / Resumo: A presente tese analisa o processo de mudança na agenda de políticas de difusão de serviços de telecom face ao processo de mudança técnica que deu origem às redes de banda larga. Inserida no paradigma tecnoeconômico da atualidade, o paradigma das TICs, o surgimento das redes de banda larga acarretou em uma série de impactos na dinâmica socioeconômica dos dias atuais - como alteração nas formas de comunicação e de acesso à informação da sociedade, alteração na estrutura organizacional do setor de telecom e dinamização macroeconômica de forma geral -, o que levou a um processo de anomalias no paradigma político anterior aplicável a esse setor, em particular, com relação ao escopo e às formas de difusão dos serviços. Diante disso, as experiências internacionais passaram a incluí-la como item das agendas de difusão de serviços em substituição aos tradicionais serviços de telefonia fixa. Observou-se que a maior parte das experiências internacionais não fez isso com base na introdução da banda larga nas agendas de regulação para universalização, mas sim, incluindo-a nas agendas de regulação para competição, em especial, entre - plataformas, e em programas públicos voltados à expansão desse serviço, tais como os diversos planos nacionais de banda larga. A análise da montagem da agenda de difusão da banda larga no Brasil mostrou que, apesar das diferenças entre seus referenciais políticos, os governos FHC, Lula e Dilma voltaram-se ao estabelecimento de uma agenda de difusão de serviços de telecom que abarcasse o componente da mudança técnica inerente ao setor, travando, para tanto, constantes diálogos com o setor privado (ainda mais intensos durante os governos Lula e Dilma), muito embora com relativa baixa participação da sociedade civil. Assim como nos casos das experiências internacionais, a despeito de não ter alterado o escopo da agenda de universalização (ainda voltado ao STFC), o termo ?banda larga? entrou pela primeira vez na agenda brasileira durante o governo Lula, que estabeleceu, entre outras medidas, o Programa Nacional de Banda Larga. Por sua vez, o governo Dilma vem buscando dar continuidade ao PNBL, além de ter estabelecido outras medidas para a superação dos entraves de difusão da banda larga no Brasil, como alto preço, baixa cobertura e alta concentração de mercado. Entre eles, é possível mencionar as assinaturas de termos de compromisso com o setor privado voltadas ao barateamento do preço do serviço e à expansão do acesso a regiões não atendidas, e o estabelecimento de mecanismos regulatórios pró-competitivos, em especial, voltados à concorrência intra-plataformas, mais adequados à condição do mercado nacional / Abstract: This thesis examines the process of change in the policy agenda of diffusion of telecom services derived from the process of technical change that gave rise to broadband networks. Inserted in today's technoeconomic paradigm, the paradigm of ICT, the emergence of broadband networks resulted in a number of impacts on the current socioeconomic dynamics - such as the introduction of new forms of communication and information access, changes in the organizational structure of telecom sector and in macroeconomic dynamics - that led to a process of anomalies in the previous political paradigm applicable to that sector, in particular with respect to the scope and forms of diffusion of services. Therefore, the international experiences now include broadband as an item on the agendas of diffusion of telecom services in substitution for traditional fixed telephony services. It was observed that, although the international experiences did not included broadband on the framework of universalization regulatory agendas, most experiences included broadband on the agenda for regulatory competition, in particular inter-platform competition, and established public programs focusing on expanding this service nationwide, also named as "national broadband plans". The analysis of the settlement of the agenda of broadband diffusion in Brazil showed that, despite the differences between their political paradigms, the FHC, Lula and Dilma's governments turned to setting an agenda for the dissemination of telecom services taking into consideration the component of dynamic technical change inherent in the telecom sector, and, at the same time, establishing constant dialogues with the private sector (even more intense during the Lula and Dilma's governments), although with relatively low participation of civil society. As noticed in the international experiences, despite not having changed the scope of the agenda of universal services (still based on the diffusion of fixed telephony), the term "broadband" first entered the Brazilian agenda during the Lula's government, which established, among other measures, the Brazilian National Broadband Plan (PNBL). In turn, the Dilma's government is seeking to continue the PNBL, at the same time as it has established other measures to overcome the barriers to broadband diffusion in Brazil, such as high prices, low coverage and high market concentration. Among them, it is possible to mention the signatures of terms of engagement with the private sector aimed at lowering costs of service and expanding access to regions that are not the focus of private investments, and the establishment of pro-competitive regulatory mechanisms, in particular, intra-platforms ones, more suitable to the conditions of the domestic broadband market / Doutorado / Teoria Economica / Doutora em Ciências Econômicas

Indiana University-Purdue University Indianapolis (IUPUI) / We propose a secure in-network data aggregation protocol with internal verification, to gain increase in the lifespan of the network by preserving bandwidth. For doing secure internal distributed operations, we show an algorithm for securely computing the sum of sensor readings in the network. Our algorithm can be generalized to any random tree topology and can be applied to any combination of mathematical functions. In addition, we represent an efficient way of doing statistical analysis for the protocol. Furthermore, we propose a novel, distributed and interactive algorithm to trace down the adversary and remove it from the network. Finally, we do bandwidth analysis of the protocol and give the proof for the efficiency of the protocol.

Carbon emissions associated with deep learning and high-performance computing have reached critical levels and must be addressed to mitigate the potential damage to the environment. Optical solutions have been widely accepted as a necessary part of any comprehensive intervention, primarily in the form of ultra-broadband wavelength-division multiplexing (WDM) optical interconnects to connect spatially distanced compute nodes and, in the further term, as dedicated photonic deep learning accelerators and photonic quantum computers. Silicon photonic interconnects provides the most promising platform for satisfying the required performance, device density, and total wafer throughput by leveraging the same mature complementary metal–oxide–semiconductor (CMOS) infrastructure used to fabricate modern electronic chips. However, implementing these links at scale requires unprecedented levels of integration density in the associated silicon photonic integrated circuit (PICs). The potential explosion in PIC density poses a significant design challenge towards guaranteeing that designers are capable of both an exhaustive design space exploration and rigorous design optimization within reasonable design cycles. Higher level design abstractions—that is, representations of designs that accurately capture system behavior while simultaneously reducing model complexity—are needed for moreefficient design and optimization of PICs. This work contributes two novel design abstractions for the rapid optimization of ultra-high-bandwidth silicon photonic interconnects. The first contribution is a novel process variation-aware compact model of strip waveguides that is suitable for circuit-level simulation of waveguide-based process design kit (PDK) elements. The model is shown to describe both loss and—using a novel expression for the thermo-optic effect in high index contrast materials—the thermo-optic behavior of strip waveguides. Experimental results prove the reported model can self-consistently describe waveguide phase, loss, and thermo-optic behavior across all measured devices over an unprecedented range of optical bandwidth, waveguide widths, and temperatures. The second contribution is a generalized abstraction for designing WDM links in the multi-freespectral range (FSR) regime, a technique for avoiding aliasing while using microresonators with FSRs smaller than the total optical bandwidth of the link. Extensive simulation and experimental results prove that the aforementioned abstractions described collectively provide a powerful toolset for rapid interconnect design and optimization. The advances in this thesis demonstrate the utility of higher-level design abstractions for fully realizing the potential silicon photonics holds for keeping pace with ever-growing bandwidth demands computing systems in the post-Moore’s Law era and beyond.

The licence is a regulatory tool that regulatory use to assist in their regulatory functions. Licences restricts operator’s’ functions, but also serve as a guideline of acceptable conduct because a licence is a legally binding document containing prescribed conditions that the licencee must meet. If the licencee does not comply with these prescribed obligations and requirements, the licence may be revoked or the licencee may be penalized (Bladwin & Cave 1999). However, in order fro the mechanism of issuing a licence to be an effective mechanism of regulation, the regulator needs to regulate effectively in order to ensure that the licencee’s performance is of acceptable standard. The purpose of this study is to investigate the relationship between issuing a licence and the licencee’s performance; to investigate whether the performance indicators, as defined by ICASA, are adequate, and to develop appropriate performance indicators in order to evaluate Cell C’s performance. Issuing a licence to licencee does not guarantee that the performance of the licencee, such as Cell C, will be effective. Thus, the licencee needs to be evaluated. The case study design has been used for this project. The methodology includes in-dept interviews, documentary analysis, and implementation evaluation research. The report concludes that Cell C has met its licence obligations, that licencing is coupled with effective mechanisms to ensure that the licencee complies with performance requirements, but that, in order for the licencee to improve its performance, effective regulatory intervention is needed. / Communication Science / MA (International Communication)

Frequency domain techniques have been widely used in indoor radio propagation measurements and modeling for telecommunication applications. This work addresses measurement of the time of arrival (TOA) of the first path for geolocation applications using results of frequency domain channel measurements. First, we analyze the effect upon TOA measurement accuracy due to: sampling period of the radio channel in the frequency domain, sampling period in the time domain used for detection of the TOA and the windowing filter used before transformation to the time domain. Then, we provide some results of measurement made in line of sight (LOS) and Obstructed LOS (OLOS) indoor environments in order to compare the characteristics of the measured TOA in these two important scenarios for indoor geolocation applications. Finally, we compare the measurement results with the ray tracing based model that had been developed previously for indoor geolocation applications.