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In this article, we study relay selection and resource allocation in a cooperative network that employs Single Carrier-Frequency Division Multiple Access (SC-FDMA) in the uplink direction such as in Long Term Evolution-Advanced (LTE-A) system. With SC-FDMA, the frequency resources assigned to a transmitter should be adjacent to each other in the frequency domain (adjacency constraint). We formulate the total data rate maximization problem as a non-linear combinatorial optimization problem. Through algebraic manipulations, we managed to convert the original problem in a Mixed Integer Linear Problem (MILP) that can be optimally solved by standard computational solvers. So as to reduce the computational complexity, we propose a low-complexity suboptimal solution to this problem. Additionally, we propose a transmit power adjustment in order to reduce the power consumption in the system and improve Energy Efficiency (EE) by exploiting the characteristics of the forwarding mechanism in the relays. Finally, we present simulation results so as to evaluate the performance of the proposed solutions and obtain insights on the effect of the main variables presented in the system model.

The use of continuous probability distributions has been widespread in problems with purely discrete nature. In general, such distributions are not appropriate in this scenario. In this paper, we introduce a class of discrete and asymmetric distributions based on the family of continuous log-symmetric distributions. Some properties are discussed as well as estimation by the maximum likelihood method. A Monte Carlo simulation study is carried out to evaluate the performance of the estimators, and censored and uncensored data sets are used to illustrate the proposed methodology.

ResumoO objetivo deste estudo é avaliar as propriedades físico-químicas e biológicas dos principais materiais indicados para capeamento pulpar direto. Revisou-se a literatura, nos bancos de dados Pubmed, Scopus e Scielo, entre 2007 e 2017, buscando artigos em português e em inglês, utilizando os descritores combinados: "Dental Pulp Capping", "Biocompatible Materials" e "Calcium Hydroxide" de literatura, 3 eram ensaios clínicos e 25 estudos laboratoriais. Através de uma leitura crítica dos títulos e dos resumos, foram selecionados 10 artigos segundo sua relevância para o estudo. Os materiais mais relatados foram o hidróxido de cálcio, o agregado trióxido mineral (MTA) e o silicato tricálcio (biodentine®). O primeiro contém propriedades antibacterianas e biocompatibilidade, entretanto possui a sua alta solubilidade como desvantagem. O segundo apresenta resultados mais previsíveis que o primeiro na formação da barreira dentinária, melhor biocompatibilidade e boa capacidade seladora. O terceiro mostra maior formação de dentina terciária, promovendo um bom selamento marginal e mostra a menor solubilidade entre eles. Assim, os materiais MTA e biodentine mostram-se materiais viáveis ao tradicional hidróxido de cálcio.Palavras-chave: Dental Pulp Capping. Biocompatible Materials. Calcium Hydroxide.

Voltage disturbances are the most frequent cause of a large range of disruption in industrial, commercial, and residential power supply systems. These disturbances are often referred to as power quality problems and affect the Power Systems causing substantial losses. To avoid the storage of a large amount of data, the first task in monitoring the power quality is the realtime detection of disturbances, which must be performed by an accurate and low-complexity system. This paper proposes a low-complexity system for power quality disturbance detection. The method makes innovative use of simple features extracted from reduced segments of the monitored voltage waveform. The extract features (the mean value, variance, energy, and the maximum and minimum values of the filtered voltage signals) require low computational effort and allow a considerable dimensional reduction of the signals, leading to simple detection algorithms. The proposed method achieves high detection rates on both simulated and real signals.