Optimization of relay selection in DF cooperative systems with outdated CSI

Relay selection has been considered as an effective method to improve the performance of cooperative communication. However, the Channel State Information (CSI) used in relay selection can be outdated, yielding severe performance degradation of cooperative communication systems. In this paper, we investigate the relay selection under outdated CSI in a Decode-and-Forward (DF) cooperative system to improve its outage performance. We formulize an optimization problem, where the set of relays that forwards data is optimized to minimize the probability of outage conditioned on the outdated CSI of all the decodable relays’ links. We then propose a novel multiple-relay selection strategy based on the solution of the optimization problem. Simulation results show that the proposed relay selection strategy achieves large improvement of outage performance compared with the existing relay selection strategies combating outdated CSI given in the literature.

O processo de elaboração do plano de preservação do conjunto urbanístico de Brasília: uma representação conceitual da política de preservação urbana no DF

This research aims to provide a reflection on the preservation practices of Brasilia as Cultural Heritage in four analytical/political dimensions: conceptual, urban, political-institutional and legal. In order to do that, the preparation process for the Plan for the Preservation of Brasilia Urban Set (PPCUB) was taken as research object. This preservation plan is representative of the context which determines the relation between goals and preservation practices in the social production process of urban space. Designed by Lucio Costa in 1957, Brasilia received the Cultural Heritage title 27 years later, in 1987. It was recognized a World Heritage Site by the United Nations Educational, Scientific and Cultural (UNESCO) in the same year as it "represents a unique artistic piece of work, a masterpiece of creative genius"; and "an outstanding example of a type of construction or architectural compound that illustrates a significant stage in history" (SILVA, 2003). Brasilia’s urban conception, also recognised in the district and federal levels, gives prominence to the 'urban scales' – monumental, residential, gregarious and bucolic – as the main aspects to be preserved. Despite being an undoubted representative, Brasilia seemingly displays a contradiction. On the one hand, the essential value of the city’s urban design is acknowledged as cultural heritage at international, national and district levels. On the other hand, numerous ways of urban interventions disregard the principles of that conception. In 2012, the international Monitoring Report raised some issues which highlight the following main needs: primary need for clear definition of the urban scales’ characteristics and boundaries; definition of a legal framework that conciliates national and district laws of occupation and use of land; creation of inter-sectors executive authority with both decision-making and financial autonomy; and promotion of heritage educational programs. This report also proposes "to cancel the current process of approval conducted by PPCUB and establish a formal consultation process through a committee made up by GDF and IPHAN, which will enable the active participation of University of Brasilia, the Architects Association, ICOMOS and local organizations" (SEDHAB, 2010). Already in its drafting process, the international recommendations evidence that preserving Brasilia’s urban design conception is not among the goals to be achieved. Thus, this research highlights that the intentional nature of PPCUB’s plans does little towards realizing the current proposals.

RF energy harvesting two-way cognitive DF relaying with transceiver impairments

This paper analyzes the impact of transceiver impairments on outage probability (OP) and throughput of decode-and-forward two-way cognitive relay (TWCR) networks, where the relay is self-powered by harvesting energy from the transmitted signals. We consider two bidirectional relaying protocols namely, multiple access broadcast (MABC) protocol and time division broadcast (TDBC) protocol, as well as, two power transfer policies namely, dual-source (DS) energy transfer and single-fixed-source (SFS) energy transfer. Closed-form expressions for OP and throughput of the network are derived in the context of delay-limited transmission. Numerical results corroborate our analysis, thereby we can quantify the degradation of OP and throughput of TWCR networks due to transceiver hardware impairments. Under the specific parameters, our results indicate that the MABC protocol achieves asymptotically a higher throughput by 0.65 [bits/s/Hz] than the TDBC protocol, while the DS energy transfer scheme offers better performance than the SFS policy for both relaying protocols.

Comportamento de compra por impulso em shopping centers: pesquisa com consumidores de Brasília-DF e Natal-RN

ARAUJO, G. P. ; RAMOS, A. S. M. . Comportamento de Compra por Impulso em Shopping Centers: pesquisa com Consumidores de Brasília-DF e Natal-RN. REAd. Revista Eletrônica de Administração (Porto Alegre. Online) , v. 16, p. 343-364, 2010.

Comportamento de compra por impulso em shopping centers: pesquisa com consumidores de Brasília-DF e Natal-RN

ARAUJO, G. P. ; RAMOS, A. S. M. . Comportamento de Compra por Impulso em Shopping Centers: pesquisa com Consumidores de Brasília-DF e Natal-RN. REAd. Revista Eletrônica de Administração (Porto Alegre. Online) , v. 16, p. 343-364, 2010.

Gestão e desenvolvimento regional na ride/DF: corsap-DF/GO como modalidade de associativismo territorial

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Humanas, Departamento de Geografia, Programa de Pós-Graduação em Geografia, 2015.

Avaliação do desempenho de fundações em edificação no DF com a utilização de técnicas de interação solo-estrutura

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2015.

Análise da eficiência de indicadores da restauração ecológica em Mata Ripária no Cerrado, Planaltina - DF

Dissertação (mestrado)—Universidade de Brasília, Departamento de Engenharia Florestal, Programa de Pós-Graduação em Ciências Florestasi, 2015.

Metodologia de avaliação de sistemas municipais de meio ambiente : aplicação a RIDE-DF e Entorno

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, Pós-Graduação em Tecnologia Ambiental e Recursos Hídricos, 2015.