267 research outputs found

    Phase distribution and correlated statistics in wireless environments : theory and experimental validation

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    Orientador: Michel Daoud YacoubTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Esta tese propõe, investiga e valida estatísticas de primeira e segunda ordens para canais com desvanecimento em ambientes sem fio. A caracterização estatística contempla tanto a obtenção de modelos teóricos quanto investigações práticas através de campanhas de medições de campo. Os modelos probabilísticos analisados aqui, chamados ?-µ e a-µ, foram recentemente propostos com o intuito de prover uma análise mais realista do canal rádio-móvel. Por apresentarem um grau de liberdade a mais do que as distribuições tradicionais, uma maior flexibilidade é alcançada. Mais especificamente, as contribuições desta tese são: a obtenção da distribuição conjunta da envoltória e da fase para canais em desvanecimento ?-µ e a validação do seu modelo de fase. Além disso, e sem menos importância, a distribuição a-µ é validada amplamente. Suas funções de distribuição cumulativa, correlação cruzada, autocorrelação e espectro de potência da envoltória, estas últimas encontradas em formulações fechadas, bem como a taxa de cruzamento de nível, são investigadas na prática através do uso de um sistema de medição de campo construído especialmente para este fim. Comparações entre o modelo de canal a-µ e os modelos tradicionais da literatura são realizadas e um excelente ajuste entre os dados teóricos e experimentais é encontradoAbstract: This thesis proposes, investigates and validates first and second order statistics of fading channels in wireless environments. The statistical characterization includes both theoretical models and practical investigations through field measurements. The investigated channel models, namely ?-µ and a-µ, have recently been proposed in order to provide a more realistic analysis of the propagated signal. Because these fading models have one more degree of freedom than the traditional distributions, a greater flexibility is achieved. More specifically, the contributions of this thesis are: the ?-µ phase-envelope joint distribution derivation and its phase model validation. Furthermore, the distribution a-µ is fully validated. Its cumulative distribution, cross-correlation, autocorrelation and power spectrum functions of the envelope, these latter obtained in closed-form expressions, and the level crossing rate, are investigated in practice by using a field measurement system, specifically built for this purpose. Comparisons between the a-µ channel model and the traditional distributions are performed and excellent fits between the theoretical and experimental data are foundDoutoradoTelecomunicações e TelemáticaDoutor em Engenharia Elétric

    Power Allocation, Relay Selection, and User Pairing for Cooperative NOMA Systems with Rate Fairness

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    Funding Information: This research was partially funded by Fundac¸ão para a Ciência e Tecnologia under the Projects CoSHARE (PTDC/EEI-TEL/30709/2017), UIDB/04111/2020, IF/00325/2015, and UIDB/50008/2020.Assuming a cooperative non-orthogonal multiple access (NOMA) system with rate fairness in a scenario with multiple users and arbitrary relays, this paper investigates adaptive power allocation (PA), relay selection (RS), and user pairing (UP) policies. Specifically, two adaptive PA optimization problems are formulated, one at the base station (BS) and another at the selected relays. Closed-form expressions for the power allocation factors are derived as well as an algorithm that provides the optimal solution at the BS. In order to show the superiority of the proposed study, our results are compared with other benchmark schemes in terms of outage probability, Jain's fairness index, and average sum rate.publishersversionpublishe

    RegBR : a novel Brazilian government framework to classify and analyze industryspecific regulations

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    Government transparency and openness are key factors to bring forth the modernization of the state. The combination of transparency and digital information has given rise to the concept of Open Government, that increases citizen understanding and monitoring of government actions, which in turn improves the quality of public services and of the government decision making process. With the goal of improving legislative transparency and the understanding of the Brazilian regulatory process and its characteristics, this paper introduces RegBR, the first national framework to centralize, classify and analyze regulations from the Brazilian government. A centralized database of Brazilian federal legislation built from automated ETL routines and processed with data mining and machine learning techniques was created. Our framework evaluates different NLP models in a text classification task on our novel Portuguese legal corpus and performs regulatory analysis based on metrics that concern linguistic complexity, restrictiveness, law interest, and industry-specific citation relevance. Our results were examined over time and validated by correlating them with known episodes of regulatory changes in Brazilian history, such as the implementation of new economic plans or the emergence of an energy crisis. Methods and metrics proposed by this framework can be used by policy makers to measure their own work and serve as inputs for future studies that could analyze government changes and their relationship with federal regulations

    RegBR: uma visão geral das aplicações

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    Government openness and transparency are key elements to build an accountable and trustworthy state, which are essential concepts to functioning democracies and market economies. Transparency in government processes increases citizen understanding and allows them to get involved by supervising and auditing government actions. RegBR was conceived as a framework to improve the legislative transparency, giving the citizens a tool to observe and monitor the Brazilian regulatory process and its characteristics. In this context, RegBR uses structured information to both create a historical regulatory flow and several regulatory metrics, which present how relevant are different sectors of the economy, how restricted are the normative acts, how linguistically complex are the regulations and, finally, how popular are theses normative acts through the eyes of the citizen and for the government.A abertura e a transparência do governo são elementos-chave para construir um estado responsável e confiável, conceitos essenciais para o funcionamento das democracias e economias de mercado. A transparência nos processos governamentais aumenta a compreensão dos cidadãos e permite que eles se envolvam na supervisão e auditoria das ações governamentais. O RegBR foi concebido como um framework para melhorar a transparência legislativa, dando ao cidadão uma ferramenta para observar e monitorar o processo regulatório brasileiro e suas características. Nesse contexto, o RegBR utiliza informações estruturadas tanto para criar um fluxo regulatório histórico quanto para conceber diversas métricas regulatórias, que apresentam quão relevantes são os diferentes setores da economia, quão restritos são os atos normativos, quão linguisticamente complexas são as regulamentações e, por fim, quão populares são esses atos normativos pelos olhos do cidadão e para o governo.La apertura y transparencia del gobierno son elementos clave para construir un estado responsable y confiable, que son conceptos esenciales para el funcionamiento de las democracias y las economías de mercado. La transparencia en los procesos de gobierno aumenta la comprensión de los ciudadanos y les permite involucrarse supervisando y auditando las acciones gubernamentales. RegBR fue concebido como un framework para mejorar la transparencia legislativa, brindando a los ciudadanos una herramienta para observar y monitorear el proceso regulatorio brasileño y sus características. En este contexto, RegBR utiliza informaciones estructuradas para crear un flujo regulatorio histórico y también varias métricas regulatorias, que presentan qué tan relevantes son los diferentes sectores de la economía, qué tan restringidos son los actos normativos, qué lingüísticamente complejas son las regulaciones y, finalmente, qué tan populares son estos actos normativos a los ojos del ciudadano y para el gobierno.Revista do Serviço Público - RSP, v. 74, n. 3, 634-656 p.Transparência, Controle e ParticipaçãoISSN Impresso: 0034-9240ISSN Eletrônico: 2357-801

    On the secrecy performance of mixed RF/UOW communication system

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    In this paper, the secrecy performance of a dual-hop mixed radio-frequency/underwater optical wireless communication (RF/UOWC) system is investigated. The considered system consists of one single antenna source node (S) communicating with one destination node (D), considered as the legitimate receiver, through the help of one amplify-and-forward (AF) relay node R equipped with multiple antennas for reception. Specifically, the relay receives the incoming signal from S via an RF link, applies maximal-ratio combining (MRC) technique, amplifies the output combined signal with a fixed gain, and then forwards it to D via an UOWC link. The transmission protocol is performed under the eavesdroppers’ attempt to overhear the RF link (i.e., SR). We derive an exact closed-form expression for the secrecy intercept probability (IP) in terms of the Fox’s H-function, or in terms of the Meijer’s G-function as a particular case. The derived secrecy performance metric is evaluated in terms of various channel and system parameters, and corroborated by Monte-Carlo simulation method. Our derived analytical formulas present an efficient tool to highlight the impact of some system and channel parameters on the secrecy performance, namely the number of relay antennas, number of eavesdropping nodes, relay gain, fading severity of RF links, and water turbulence severity of the UOWC link

    QoS management and flexible traffic detection architecture for 5G mobile networks

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    The next generation of 5G networks is being developed to provide services with the highest Quality of Service (QoS) attributes, such as ultra-low latency, ultra-reliable communication, high data rates, and high user mobility experience. To this end, several new settings must be implemented in the mobile network architecture such as the incorporation of Network Function Virtualization (NFV) and Software-Defined Networking (SDN), along with the shift of processes to the edge of the network. This work proposes an architecture combining the NFV and SDN concepts to provide the logic for Quality of Service (QoS) traffic detection and the logic for QoS management in next-generation mobile networks. It can be applied to the mobile backhaul and the mobile core network to work with both 5G mobile access networks or current 4G access networks, keeping backward compatibility with current mobile devices. In order to manage traffic without QoS and with QoS requirements, this work incorporates Multiprotocol Label Switching (MPLS) in the mobile data plane. A new flexible and programmable method to detect traffic with QoS requirements is also proposed, along with an Evolved Packet System (EPS)-bearer/QoS-flow creation with QoS considering all elements in the path. These goals are achieved by using proactive and reactive path setup methods to route the traffic immediately and simultaneously process it in the search for QoS requirements. Finally, a prototype is presented to prove the benefits and the viability of the proposed concepts

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good
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