Estimation of basis frequencies for time-varying SIMO channels : a second-order method

The complex exponential basis expansion model (CE-BEM) provides an accurate description for the time-varying (TV) channels encountered in mobile communications. Many blind channel identification and equalization approaches based on the CE-BEM require precise knowledge of the basis frequencies of TV channels. Existing methods for basis frequency estimation usually resort to the higher-order statistics of channel outputs and impose strict constraints on the source signal. In this paper, we propose a novel method to estimate the basis frequencies for blind identification and equalization of time-varying single-input multiple-output (SIMO) finite-impulse-response (FIR) channels. The proposed method exploits only the second-order statistics of channel outputs and does not require strong conditions on the source signal. As a result, it exhibits superior performance to the existing basis frequency estimation methods. The validity of our method is demonstrated by numerical simulations.

CM-based blind equalization of time-varying SIMO-FIR channel with single pulsation estimation

It is known that the constant modulus (CM) property of the source signal can be exploited to blindly equalize time-invariant single-inputmultiple-output (SIMO) and finite-impulse-response (FIR) channels. However, the time-invariance assumption about the channel cannot be satisfied in several practical applications, e.g., mobile communication. In this paper, we show that, under some mild conditions, the CM criterion can be extended to the blind equalization of a time-varying channel that is described by the complex exponential basis expansion model (CE-BEM). Although several existing blind equalization methods that are based on the CE-BEM have to employ higher order statistics to estimate all nonzero channel pulsations, the CM-based method only needs to estimate one pulsation using second-order statistics, which yields better estimation results. It also relaxes the restriction on the source signal and is applicable to some classes of signals with which the existing methods cannot deal.

Channel estimation for time-varying MIMO relay systems

In this paper, we investigate the channel estimation problem for multiple-input multiple-output (MIMO) relay communication systems with time-varying channels. The time-varying characteristic of the channels is described by the complex-exponential basis expansion model (CE-BEM). We propose a superimposed channel training algorithm to estimate the individual first-hop and second-hop time-varying channel matrices for MIMO relay systems. In particular, the estimation of the second-hop time-varying channel matrix is performed by exploiting the superimposed training sequence at the relay node, while the first-hop time-varying channel matrix is estimated through the source node training sequence and the estimated second-hop channel. To improve the performance of channel estimation, we derive the optimal structure of the source and relay training sequences that minimize the mean-squared error (MSE) of channel estimation. We also optimize the relay amplification factor that governs the power allocation between the source and relay training sequences. Numerical simulations demonstrate that the proposed superimposed channel training algorithm for MIMO relay systems with time-varying channels outperforms the conventional two-stage channel estimation scheme.

Superimposed channel training algorithm for time-varying MIMO relay systems

Two-way relaying systems are known to be capable of providing higher spectral efficiency compared with one-way relaying systems. However, the channel estimation problem for two-way relaying systems becomes more complicated. In this paper, we propose a superimposed channel training scheme for two-way MIMO relay communication systems, where the individ-ual channel information for users-relay and relay-users links are estimated. The optimal structure of the source and relay training sequences are derived when the mean-squared error (MSE) of channel estimation is minimized. We also optimize the power allocation between the source and relay training sequences to improve the performance of the algorithm. Numerical examples are shown to demonstrate the performance of the proposed channel training algorithm.

A comunicação do ritual de autossacrifício do corpo: os penitentes de Barbalha - CE

Dissertação apresentada ao Programa de Mestrado em Comunicação da Universidade Municipal de São Caetano do Sul

A importância do microcrédito para os empreendedores: um estudo com os grupos solidários de Fortaleza /CE

This study aims to understand the changes in the improvement of economic and social conditions of small entrepreneurs who participate in solidarity groups linked to the Non-Governmental Organization (NGO) "X" in Fortaleza city, Ceará, through the use of productive-guided microcredit. It is come a research in exploratory and descriptive nature, with a quantitative and qualitative approach. Data were collected from the small entrepreneurs by applying a questionnaire, as well as through structured interviews with group leaders. They were worked on issues relating to income generation, employment generation, housing and health conditions, dietary pattern and leisure activities of small entrepreneurs and their families before and after the union to solidarity groups and use of productive-guided microcredit. The research showed that the use of microcredit has interfered with social and economic life of these small entrepreneurs, generating positive effects

Adequação bioclimática para os espaços urbanos abertos do centro de Fortaleza, CE

This research presents a study investigating the correlation between the environmental-physycal charcateristics of cities and the formation of its micro-climates. The study was conducted in the central area of Fortaleza characterized as a stable and consolidated area, where the city originated and currently faces serious problems in its urban dynamics. The points of measurements were determined by the elaboration and analysis of topography maps, height of buildings, land use, type of surface coating and vegetation, following the methodology of Katzschner (1997). A zoning map was then determined, according to common morphological characteristics of the 12 measurement points, which were based on a set of Romero s (2001) bioclimatic criteria. Air measurements, temperature, humidity, intensity and direction of winds were made in transect form in two different circuits in the study area, with six points of data collection in each area, in three different times: 6:00 am, 1:00pm and 7:00pm, during two periods of the year: August 2008 and March 2009. The results verified the influence of different environmental-physical types in the behavior of the climatic variables that were collected. A verticalização tão condenada em algumas situações se bem equilibrada e controlada pode reduzir as temperaturas do ar através do sombreamento dos espaços urbanos e possibilidade de maior permeabilidade a ventilação natural. The highest average air temperature and lower humidity were recorded at the point I at all times. This situation may have been in result of the high density, poor vegetation and extended paving of the ground. According to the results, it s clear the positive influence vegetation has on easing air temperature. Another indicator observed that areas with a greater variation in building heights tend to present decreased average air temperature. High rise structure, planned in accordance to urban air quality parameters, can reduce air temperatures by the shading of urban spaces and the possibility of greater penetration of natural ventilation

O Plano Diretor como instrumento de gestão da cidade: o caso da cidade de Fortaleza/CE

According to article 182 of the Brazilian Federal Constitution, cities should perform social function, what brings the concept that the city should be a place for one to live well. For that to happen, it should be well administered by its public managers. However, so that there is a sound administration, one that really performs that social function, there must be, first, an efficient planning. We understand that such a thing occurs when the master plan is the main planning instrument of a city and serves as basis for its administration. We notice, however, that in most of the cities the master plan is formulated as a law that regulates urban planning but that both the population and the government most of the times are not aware of its importance concerning the relevant issues related to municipal administration, such as its relationship with the economy, taxation, the social issue, land use regulation, and, in summary, with all the aspects that constitute and that a municipal government should manage in the best possible way. One also knows that, in general, the attempt of city planning has always been connected to the duration of a mandate and that way public managers many times implement restricted measures aiming to just attain a political-electoral objective and publicizing their administration. That implies actions and works that in some cases have negative impacts or ones that cannot be removed from the cities. This study intends to show that the master plan should be the planning instrument guiding the municipal administration but that, however, what we note is a lack of connection between that instrument and the government guidelines of the municipal managers. In order to study what happens to the cities that have a planning which is not taken into account in its administration, we will use the city of Fortaleza, capital of the State of Ceará as a case study. Historically, in Fortaleza the public managers have seldom decided to administer the city in according to the master plans developed for it. We should emphasize that planning begins in the city quite late and until the current days it is being substituted by temporary measures. Through the analysis of the planning process and of the urban management of the city of Fortaleza, especially the master plans predicted since 1933, we explain that if such plans had been implemented, they could have been important tools for its administration to attain a social function, becoming therefore a place for one to live well

Instituições prevalecentes, tradição e persistência no extrativismo da cera de carnaúba em Limoeiro do Norte -CE

A presente pesquisa visa entender os fatores que explicam a manutenção dos aspectos artesanais no extrativismo da cera de carnaúba em Limoeiro do Norte. Justificamos a exploração desse tema pelo fascínio do autor pelo tema e por ser esse recurso ainda uma importante fonte de renda para produtores e trabalhadores rurais no respectivo município. Objetivamos nessa pesquisa identificar as razões pelas quais a atividade mantém seu padrão tecnológico intacto. Primeiro objetivamos uma descrição do processo produtivo da cera, tanto no passado, quanto no presente, comparando estes momentos e ressaltando o caráter artesanal da atividade, além de analisar a importância atual da atividade para aqueles que ainda lidam com esse tipo de produção, bem como procuramos revelar estrutura histórica e institucional que permeia a lógica e as escolhas destes produtores, a qual pode explicar a preservação destes aspectos artesanais. Utilizando o referencial teórico do institucionalismo, explicamos que a preservação destes aspectos artesanais, ocorre em virtude da prevalência de determinadas instituições, como a memória coletiva cultivada entre os rendeiros idosos e resistentes, a concentração fundiária, responsável pelo arrendamento e também as restritas possibilidades de investimento e poupança no processo produtivo, em face do baixo nível de renda de produtores, os quais com um produto pouco competitivo no mercado, pouco podem fazer para inovar tecnologicamente.

Análise do processo de internalização de propostas de educação ambiental em escolas de Ensino Médio no município de Acaraú-CE

To insert environmental education in the school is a very hard task, although the question has been largely discussed since some years ago. The main object of this research is limited to the way the contents of Environmental Education are inserted in school programs, as well as to assert that, as a law, it must be put in practice not only because it is obligatory, but because it is important to school programs, especially to Acaraú´s primary and secondary schools, having in view the importance of the natural resources in which schools are inserted and the development of ways to solve problems related to the quality of life of the dwellers of these places. It is important the study of the law 9795/99 on Environmental Education, passed on July 25th, 2005, by means of the decree no. 4.281, established in the Municipal Organic Law and other documents ruling the Environmental Education. Our purpose is to give orientation on Environmental Education to the above-mentioned schools aiming at the permanent formation about that subject, in order to constitute, in the future, a real net between school and community and to spread out concepts about sustainability. This way, poverty conditions should be faced as environmental problems, bringing about the relationship between natural resources and poverty. The making of shrimp beds, predatory fishing, swamp degradation and irregular occupation constitute elements to this research. The theoretic terms are based upon principles of Environmental Education, area sustainability and inter-disciplinarily and trans-disciplinarily in Environmental Sciences, which have been applied under the form of capacities and the presentation of documents, projects, maps, discussions and reflections about the mass social movements as a positive consequence of the implementation of this project

Estudo geoquímico de solos em áreas degradadas no município de Sobral (CE) com vistas à sua recuperação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Parques urbanos de Fortaleza-CE: espaço vivido e qualidade de vida

Pós-graduação em Geografia - IGCE

Código de conduta: uma potencialidade para o desenvolvimento sustentável da floricultura do Agropolo Cariri/CE

Pós-graduação em Geografia - IGCE

Indústria têxtil e crescimento econômico: uma abordagem geográfica da evolução, estrutura e dinâmica da aglomeração produtiva de redes de dormir em Jaguaruana - CE

Pós-graduação em Geografia - IGCE

O princípio (instituidor) da intervenção mínima: a proteção do bem jurídico e a (des)criminalização no direito eleitoral

No presente trabalho, questiona-se a necessidade da intervenção do direito penal no direito eleitoral para proteger os bens jurídicos. Constata-se que, no caso do Brasil, essa intervenção penal no direito eleitoral é significativa e ocorre por intermédio de diversas leis, das quais a principal é o Código Eleitoral (CE) em vigor. O ponto de partida desta pesquisa é a teoria do bem jurídico-penal, com destaque para a sua função crítica. É feita uma aproximação dessa teoria crítica do bem jurídico-penal com o Estado Democrático de Direito e a formulação teórica de Ronald Dworkin e Lenio Streck a respeito dos princípios do direito, com ênfase no princípio (instituidor) da intervenção mínima, no âmbito do direito penal, e seus componentes de garantia, entre os quais a proteção exclusiva de bens jurídicos, a fragmentariedade e a subsidiariedade. A partir daí, é estabelecida a relação entre a proteção não penal de bens jurídicos (relevantes) no direito eleitoral e a (des)criminalização no direito eleitoral, contrapondo-se as teses do expansionismo e do minimalismo penal. A questão fundamental da pesquisa é relacionar esses conceitos para indagar sobre a (des)necessidade dos tipos penais eleitorais e buscar, para o modelo brasileiro, uma proposta não penal de proteção de bens jurídicos no âmbito eleitoral.