Modelo de propagação indoor multi-andar em 2.4 GHz com estimativa de parâmetros de QoS em chamadas VoIP

O advento de novas formas multimídia tem atraído uma clientela exigente, onde preocupação não é somente com o serviço, mas também, com a qualidade que esse serviço pode ser oferecido. As WLAN (Wireless Local Area Networks) tornaram-se a forma mais comum de roteamento de Internet, devido ao seu baixo custo e facilidade de implementação. Para realizar um bom roteamento é necessário um planejamento, utilizando-se modelos. Os modelos de propagação existentes na literatura fazem a predição da intensidade do sinal, mas algumas vezes não contemplam a previsão de um bom serviço. Nesse sentido a presente dissertação propõe-se a elaborar um modelo de propagação empírico indoor multi-andar que não só prediz a potência recebida, mas também faz uma previsão para algumas métricas de QoS (Quality of Service) de chamadas VoIP (Voice over Internet Protocol). Para a elaboração do modelo proposto foram feitas campanhas de medição, em um prédio de dois andares, em pisos distintos mantendo-se a posição do ponto de acesso (PA) fixa. Estudos de geometria analítica para a contagem e agregação de perdas em pisos e paredes. Os resultados do modelo proposto foram comparados com um modelo da literatura que tem um comportamento similar, onde é possível verificar o melhor desempenho do modelo proposto, e para efeito de estudo um andar completamente simulado foi introduzido para avaliação.

Green-Markov models - new optimization strategies: a case study for user allocation in co-channel macro/femto networks

ABSTRACT: The femtocell concept aims to combine fixed-line broadband access with mobile telephony using the deployment of low-cost, low-power third and fourth generation base stations in the subscribers' homes. While the self-configuration of femtocells is a plus, it can limit the quality of service (QoS) for the users and reduce the efficiency of the network, based on outdated allocation parameters such as signal power level. To this end, this paper presents a proposal for optimized allocation of users on a co-channel macro-femto network, that enable self-configuration and public access, aiming to maximize the quality of service of applications and using more efficiently the available energy, seeking the concept of Green networking. Thus, when the user needs to connect to make a voice or a data call, the mobile phone has to decide which network to connect, using the information of number of connections, the QoS parameters (packet loss and throughput) and the signal power level of each network. For this purpose, the system is modeled as a Markov Decision Process, which is formulated to obtain an optimal policy that can be applied on the mobile phone. The policy created is flexible, allowing different analyzes, and adaptive to the specific characteristics defined by the telephone company. The results show that compared to traditional QoS approaches, the policy proposed here can improve energy efficiency by up to 10%.

Previsão multi-passos a frente do preço de energia elétrica de curto prazo no mercado brasileiro

A predição do preço da energia elétrica é uma questão importante para todos os participantes do mercado, para que decidam as estratégias mais adequadas e estabeleçam os contratos bilaterais que maximizem seus lucros e minimizem os seus riscos. O preço da energia tipicamente exibe sazonalidade, alta volatilidade e picos. Além disso, o preço da energia é influenciado por muitos fatores, tais como: demanda de energia, clima e preço de combustíveis. Este trabalho propõe uma nova abordagem híbrida para a predição de preços de energia no mercado de curto prazo. Tal abordagem combina os filtros autorregressivos integrados de médias móveis (ARIMA) e modelos de Redes Neurais (RNA) numa estrutura em cascata e utiliza variáveis explanatórias. Um processo em dois passos é aplicado. Na primeira etapa, as variáveis explanatórias são preditas. Na segunda etapa, os preços de energia são preditos usando os valores futuros das variáveis exploratórias. O modelo proposto considera uma predição de 12 passos (semanas) a frente e é aplicada ao mercado brasileiro, que possui características únicas de comportamento e adota o despacho centralizado baseado em custo. Os resultados mostram uma boa capacidade de predição de picos de preço e uma exatidão satisfatória de acordo com as medidas de erro e testes de perda de cauda quando comparado com técnicas tradicionais. Em caráter complementar, é proposto um modelo classificador composto de árvores de decisão e RNA, com objetivo de explicitar as regras de formação de preços e, em conjunto com o modelo preditor, atuar como uma ferramenta atrativa para mitigar os riscos da comercialização de energia.

Minimal composite Higgs models at the LHC

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new probabilistic canopy dynamics model (SLCD) that is suitable for evergreen and deciduous forest ecosystems

There are strong uncertainties regarding LAI dynamics in forest ecosystems in response to climate change. While empirical growth & yield models (G&YMs) provide good estimations of tree growth at the stand level on a yearly to decennial scale, process-based models (PBMs) use LAI dynamics as a key variable for enabling the accurate prediction of tree growth over short time scales. Bridging the gap between PBMs and G&YMs could improve the prediction of forest growth and, therefore, carbon, water and nutrient fluxes by combining modeling approaches at the stand level.Our study aimed to estimate monthly changes of leaf area in response to climate variations from sparse measurements of foliage area and biomass. A leaf population probabilistic model (SLCD) was designed to simulate foliage renewal. The leaf population was distributed in monthly cohorts, and the total population size was limited depending on forest age and productivity. Foliage dynamics were driven by a foliation function and the probabilities ruling leaf aging or fall. Their formulation depends on the forest environment.The model was applied to three tree species growing under contrasting climates and soil types. In tropical Brazilian evergreen broadleaf eucalypt plantations, the phenology was described using 8 parameters. A multi-objective evolutionary algorithm method (MOEA) was used to fit the model parameters on litterfall and LAI data over an entire stand rotation. Field measurements from a second eucalypt stand were used to validate the model. Seasonal LAI changes were accurately rendered for both sites (R-2 = 0.898 adjustment, R-2 = 0.698 validation). Litterfall production was correctly simulated (R-2 = 0.562, R-2 = 0.4018 validation) and may be improved by using additional validation data in future work. In two French temperate deciduous forests (beech and oak), we adapted phenological sub-modules of the CASTANEA model to simulate canopy dynamics, and SLCD was validated using LAI measurements. The phenological patterns were simulated with good accuracy in the two cases studied. However, IA/max was not accurately simulated in the beech forest, and further improvement is required.Our probabilistic approach is expected to contribute to improving predictions of LAI dynamics. The model formalism is general and suitable to broadleaf forests for a large range of ecological conditions. (C) 2014 Elsevier B.V. All rights reserved.

Performance of a New One-step Multi-mode Adhesive on Etched vs Non-etched Enamel on Bond Strength and Interfacial Morphology

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

New physics from warped compact extra dimensions: from model building to colliders signals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A new deformation of W-infinity and applications to the two-loop WZNW and conformal affine Toda models

We construct a centerless W-infinity type of algebra in terms of a generator of a centerless Virasoro algebra and an abelian spin 1 current. This algebra conventionally emerges in the study of pseudo-differential operators on a circle or alternatively within KP hierarchy with Watanabe's bracket. Construction used here is based on a spherical deformation of the algebra W ∞ of area preserving diffeomorphisms of a 2-manifold. We show that this deformation technique applies to the two-loop WZNW and conformal affine Toda models, establishing henceforth W ∞ invariance of these models.

New fermions and a vectorlike third generation in SU(3)(C)circle times SU(3)(L)circle times U(1)(N) models

We study two 3-3-1 models with (i) five (four) charge 2/3 (-1/3) quarks and (ii) four (five) charge 2/3 (-1/3) quarks and a vectorlike third generation. Possibilities beyond these models are also briefly considered.

Open innovation and user s involvement in new product development: a case study in the automotive sector

Innovation is an essential factor for obtaining competitive advantages. The search for external knowledge sources for product creation, which can contribute to the innovation process, has become a constant among companies, and users play an important role in this search. In this study, we aimed to analyze user’s involvement in the product development process based on open innovation concepts. We used the unique case study research method. This study was carried out in an automotive company that has developed a project of a concept car involving user’s through the Web 2.0. With such scope, the research demonstrates that users can contribute not only with generation of ideas but also with the innovation process itself.

New Business Models And Editorial Exemption: A Study On Service Journalism Based On Ecommerce Operations

The paper presents and discusses business strategies based on the association from journalistic content to new commercial practices in digital media. We describe selected examples from Folha de S. Paulo and El País involving service guides, links and ecommerce advertisements. The employed method provides content analysis to illustrate how the search for new business models in journalism may conduct its commercial activities beyond the conventional sale of advertising and subscriptions, including a discussion on the challenges and implications of this practice. The hypothesis is demonstrated by describing operations for the sale of tickets, books, music, and films related to news features and service journalism contents. The text finally wonders and discusses how such commercial actions may affect editorial autonomy and publishing exemption.

Flexibility and modeling in business processes: a multi-dimensional relationship

Over the last few years, Business Process Management (BPM) has achieved increasing popularity and dissemination. An analysis of the underlying assumptions of BPM shows that it pursues two apparently contradicting goals: on the one hand it aims at formalising work practices into business process models; on the other hand, it intends to confer flexibility to the organization - i.e. to maintain its ability to respond to new and unforeseen situations. This paper analyses the relationship between formalisation and flexibility in business process modelling by means of an empirical case study of a BPM project in an aircraft maintenance company. A qualitative approach is adopted based on the Actor-Network Theory. The paper offers two major contributions: (a) it illustrates the sociotechnical complexity involved in BPM initiatives; (b) it points towards a multidimensional understanding of the relation between formalization and flexibility in BPM projects.

Exact cosmological solutions of models with an interacting dark sector

In this work we extend the first order formalism for cosmological models that present an interaction between a fermionic and a scalar field. Cosmological exact solutions describing universes filled with interacting dark energy and dark matter have been obtained. Viable cosmological solutions with an early period of decelerated expansion followed by late acceleration have been found, notably one which presents a dark matter component dominating in the past and a dark energy component dominating in the future. In another one, the dark energy alone is the responsible for both periods, similar to a Chaplygin gas case. Exclusively accelerating solutions have also been obtained.

Present bounds on new neutral vector resonances from electroweak gauge boson pair production at the LHC

Several extensions of the standard model predict the existence of new neutral spin-1 resonances associated with the electroweak symmetry breaking sector. Using the data from ATLAS (with integrated luminosity of L = 1.02 fb(-1)) and CMS (with integrated luminosity of L = 1.55 fb(-1)) on the production of W+W- pairs through the process pp --> l(+)l(-)' is not an element of(T), we place model independent bounds on these new vector resonances masses, couplings, and widths. Our analyses show that the present data exclude new neutral vector resonances with masses up to 1-2.3 TeV depending on their couplings and widths. We also demonstrate how to extend our analysis framework to different models with a specific example.