Abstract Multicarrier and multiple input–multiple output (MIMO) techniques have become popular in wireless communications over multipath fading channels in recent years. This thesis firstly considers the characterization and simulation of fading mobile radio channels for MIMO multicarrier systems. Secondly, the performance of spread-spectrum multicarrier (MC) code-division multiple-access (CDMA) with multirate transmission is analyzed. Thirdly, the analysis is applied to ultra-wideband (UWB) orthogonal frequency-division multiplexing (OFDM) systems enhanced with frequency-domain code-division multiplexing (CDM). The response of a small-scale fading channel is derived as a function of time, transmit and receive antenna positions, and subcarrier frequency, which leads to a tapped delay-line model with time-, space-, and frequency-selective taps. The taps are modeled as a sum of a deterministic line-of-sight or dominant scattered path and a zero-mean Gaussian part composed of a number of unresolvable scattered paths and, therefore, are Rice fading. The Gaussian parts have the desired temporal and spatiospectral correlations generated by time-correlation shaping filtering and a space-frequency correlation transformation, respectively. The simulator achieves a good accuracy while retaining a reasonable computational complexity. The generic performance analysis of MC-CDMA includes both the multicode and variable spreading factor (VSF) multirate schemes that are inherent for CDMA and capable of providing efficient support for services of different required data rates. The analysis also takes into account the intersymbol interference caused by the multipath delay components exceeding a guard interval, which is commonly omitted in the literature by assuming the guard interval to be longer than the maximum delay spread. Results comparing and pointing out notable differences in the error rate performance of the two multirate schemes in conjunction with six different combining techniques are presented for a synchronous downlink and both a synchronous and asynchronous uplink. The analysis of CDM-enhanced OFDM-UWB involves first a single piconet with different combinations of the VSF and multicode schemes. Frequency-domain spreading is found to improve the performance remarkably when a sufficient spreading factor and a suitable subcarrier combining method are used. Subsequently, CDMA of simultaneously operating piconets (SOPs) with either the VSF or multicode scheme is considered. While both multirate schemes result in a similar performance when the number of SOPs is large, notable differences arise when there are only a few SOPs.

In recent times, there has been a significant amount of research regarding the physical layer of wireless communications . The part of the physical layer, which cannot be ignored, is channel propagation. Different environments have different channels. Path loss, slow fading, fast fading and multipath fading are all involved in decisions regarding the condition of the channel . Based on related research, a number of empirical channel models are put forward to simulate a real environment with regards to communication and there are some simulation softwares that are able to implement those different channels. These include Matlab which is regarded as the best simulation software for the physical layer in wireless communication. OPNET is another network modeling simulation software, which could implement the entire process of the network communication, which Matlab is not able to complete . The network layer of OPNET is very mature and has the ability to implement different routing protocols. However, the description of the physical layer in OPNET is poor and there is only simple path loss model in pipeline modeling in OPNET. Thus, the objective of this thesis is to implement different channel models in OPNET and to make it capable to simulate in as close a manner as possible to a real environment.

This dissertation demonstrates how the Weltanschauung found in Álvaro Mutis´s oeuvre is profoundly influenced by a late romantic conscience found in the Latin American posvanguardia generation (1920 – 1940). Melancholy –as late modern affective condition- and fading of the subject –as narrative and aesthetic imaginary- are two central figures in his fictional universe. As a consequence of this, some of the heroes and topics in Mutis’s oeuvre are in dialogue with the main topics of the first literary movement in Hispanic America, Modernism. Some of them are: a religious ambiance in their prose, hedonism, cosmopolitanism, decadentism, Latin American landscape as entropy and a fractured self. There is a narrative logic in the literary corpus analyzed –which one can extend to Mutis’ s oeuvre. The hero, before starting his adventure, begins a psychological phenomenology called “fading of the subject”, which is a symbolic process that affects not only his stability as a hero but also the enterprise to which he is committed; all this thanks to his “melancholic condition”. This emotional process begins by revealing poetic images of internal destruction, amalgamation and death, which the hero transfers to the external world. In some of the texts analyzed this process concludes by producing death and devastation (El Húsar, La muerte del estratega), in others there is an urgent need to a symbolic resignification (Amirbar) that allows the hero to survive and start a new adventure. This “spiritual condition” is something Maqroll - Mutis’ main character- knows well when someone asks him about his precarious physical condition, “The tropical fevers...I have them already!” (Amirbar 491)

The aggregate interference distribution in cognitive radio networks is studied in a rigorous and analytical way using the popular Poisson point process model. While a number of results are available for this model for non-cognitive radio networks, cognitive radio networks present extra levels of difficulties for the analysis, mainly due to the exclusion region around the primary receiver, which are typically addressed via various ad-hoc approximations (e.g., based on the interference cumulants) or via the large-deviation analysis. Unlike the previous studies, we do not use here ad-hoc approximations but rather obtain the asymptotic interference distribution in a systematic and rigorous way, which also has a guaranteed level of accuracy at the distribution tail. This is in contrast to the large deviation analysis, which provides only the (exponential) order of scaling but not the outage probability itself. Unlike the cumulant-based analysis, our approach provides a guaranteed level of accuracy at the distribution tail. Additionally, our analysis provides a number of novel insights. In particular, we demonstrate that there is a critical transition point below which the outage probability decays only polynomially but above which it decays super-exponentially. This provides a solid analytical foundation to the earlier empirical observations in the literature and also reveals what are the typical ways outage events occur in different regimes. The analysis is further extended to include interference cancelation and fading (from a broad class of distributions). The outage probability is shown to scale down exponentially in the number of canceled nearest interferers in the below-critical region and does not change significantly in the above-critical one. The proposed asymptotic expressions are shown to be accurate in the non-asymptotic regimes as well.

The thesis is concerned with capacity and coverage enhancement of OFDMA heterogeneous cellular systems with a specific focus on fractional frequency reuse (FFR), femtocells and amplify-and-forward (AF) relay systems. The main aim of the thesis is to develop new mathematical analysis for the spectral efficiency and outage probability of multi-cells multi-tier systems in diverse traffic, interference and fading scenarios. In the first part of the thesis, a new unified mathematical framework for performance analysis of FFR and soft frequency reuse (SFR) schemes is developed. This leads to new exact expressions of FFR and SFR area spectral efficiency in downlink and uplink scenarios which account for a mixture of frequency reuse factors in a homogeneous cellular system. The mathematical framework is extended to include modelling and performance analysis of FFR systems with elastic data traffic. Further analysis is carried out in relation to the performance of FFR and/or SFR schemes, in terms of energy efficiency and base station cooperation. The new proposed analytical framework can lead to a better understanding and computationally efficient performance analysis of next generation heterogeneous cellular systems. Next generation cellular systems are characterized by an increase in the spatial node density to improve the spectral efficiency and coverage, especially for users at home and at the cell edges. In this regard, relays and femtocells play a major role. Therefore, relays and femocells are the focus of the second part of the thesis. Firstly, we present a new and unified spectral efficiency analysis in dual-hop fixed-gain AF relay systems over generalised interferences models. The generalised interference models are either based on the Nakagami-m fading with arbitrary distance or on spatial Poisson Point Process in case of randomly deployed heterogeneous interferers. The models have been considered separately in the open literature due to the complexity of the mathematical analysis. Secondly, the outage probability is utilised to deduce the femtocell exclusion region for FFR system and a new static resource allocation scheme is proposed for femtocells which improve the capacity. The work presented in the thesis has resulted in the publication of seven scientific papers in prestigious IEEE journals and conferences.

Children with autism show deficits in communication skills, including joint attention, a component of which is following the line of regard. Two experiments were conducted. The first experiment examined how prompting and fading procedures effected following the line of regard in a child with autism. The second experiment examined this effect on the child's learning the names of novel objects. One 10-year-old boy, with a primary diagnosis of autism, participated. A changing criterion design was used in Experiment I. Experiment II used a succession of interventions to assess incidental learning of novel object names. Results indicate that prompting and fading with reinforcement was an effective training procedure for teaching this child to follow the line of regard. However, this skill did not automatically lead to the child's learning the names of novel objects.

Orientador: Michel Daoud Yacoub / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-22T07:34:34Z (GMT). No. of bitstreams: 1 Leonardo_ElvioJoao_D.pdf: 1695806 bytes, checksum: 1768ab9d1e09da8bf904b86bdff2c984 (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

Orientador: Ana Cláudia Moreira Almeida-Verdu / Resumo: A deficiência auditiva sensorioneural, de grau severo-profundo, bilateral e pré-lingual pode comprometer a aquisição de repertórios verbais. O implante coclear (IC) é um dispositivo auditivo que habilita o acesso aos sons da fala e permite a aprendizagem de habilidades de ouvinte e de falante. Estudos entre a Fonoaudiologia e a Análise do Comportamento têm adotado o modelo das relações de equivalência e investigado as condições de ensino sob as quais essa população aprende as habilidades auditivas e as relações que o ouvir estabelece com o falar, de palavras às sentenças. O procedimento de matching to sample (MTS) tem sido utilizado para ensinar relações condicionais entre estímulos. Procedimentos associados ao MTS minimizam a ocorrência de erros durante a aprendizagem do reconhecimento auditivo de sentenças, como o fading out. O objetivo geral desta pesquisa foi controlar o efeito do procedimento de fading out no ensino de discriminações condicionais entre sentença de quatro termos ditadas e figuras de ações, de modo a verificar qual rotina de ensino (fading blocado ou fading randomizado) é mais eficaz. Foram avaliados também os efeitos desses procedimentos sobre a formação de classes de estímulos equivalentes, a precisão da fala na nomeação de figuras e os desempenhos recombinativos. Participaram duas alunas, com idade entre sete e nove anos, com deficiência auditiva sensorioneural, bilateral, de grau moderado a profundo, e usuárias de IC. As sentenças foram organizadas em ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sensorineural hearing loss, severe-profound, bilateral and pre-lingual, can compromise the acquisition of verbal repertoires. The cochlear implant (CI) is an auditory device that enables access to speech sounds and allows the learning of listening and speaking skills. Studies between Speech-Language Pathology and Behavior Analysis have adopted the equivalence relations model and investigated the teaching conditions under which this population learns the auditory skills and the relationships that listening establishes with speaking, from words to sentences. The matching to sample (MTS) procedure has been used to teach conditional relations between stimuli. Procedures associated with the MTS minimize the occurrence of errors during the learning of auditory recognition of sentences, such as fading out. The general objective of this research was to control the effect of the fading out procedure in the teaching of conditional discriminations between sentences of four dictated terms and action figures, in order to verify which teaching routine (blocked fading or randomized fading) is more effective. The effects of these procedures on the formation of equivalent stimulus classes, the accuracy of speech in the naming of figures and the recombinative performances were also evaluated. Two students participated, aged between seven and nine years, with bilateral sensorineural hearing loss, of moderate to profound degree, and CI users. The sentences were organized in two matrices (Sets 1 ... (Complete abstract click electronic access below) / Mestre

The initial and maintenance effects of a Daily Behavior Report Card (DBRC) intervention and fading procedure on Academic Engaged Time (AET) of a 6-year-old boy with Developmental Delay and Attention Deficits were evaluated with a reversal design. Following an initial baseline, the DBRC was implemented and then completely removed followed by reapplication of the DBRC. Subsequently, the report card was gradually reduced in the frequency of its use from very daily to every other day. Increased AET reliably varied with the application and then removal of the DBRC. Whereas complete removal of the DBRC resulted in substantial decreases in AET, response dependent fading of the card was associated with AET of 80% or above. Teacher intervention ratings demonstrated social validity of the intervention in terms of its effectiveness, acceptability and efficiency. Research and practical issues are discussed.

Tato diplomová práce se zabývá analýzou, návrhem a simulací modelu fyzické vrstvy bezdrátového komunikačního systému IEEE 802.11af. V práci je především popsána vysílací část komunikačního systému s důrazem na zpracování IEEE 802.11af signálu. Následně je vytvořeno blokové schéma a model pro vysílací a přijímací části ve vysílacích módech SISO a MIMO. Model je realizován s grafickým uživatelským rozhraním v programovém prostředí MATLAB. Vytvořená aplikace slouží k prozkoumání vlastností IEEE 802.11af modelu na základě jeho systémových parametrů. Systémové parametry jsou volitelné uživatelem a aplikace poskytuje možnost simulace různých přenosových scénářů.