Eduardo Marques

A Parallel Hardware Architecture for Scale and Rotation Invariant Feature Detection

This paper proposes a parallel hardware architecture for image feature detection based on the scale invariant feature transform algorithm and applied to the simultaneous localization and mapping problem. The work also proposes specific hardware optimizations considered fundamental to embed such a robotic control system on-a-chip. The proposed architecture is completely stand-alone; it reads the input data directly from a CMOS image sensor and provides the results via a field-programmable gate array coupled to an embedded processor. The results may either be used directly in an on-chip application or accessed through an Ethernet connection. The system is able to detect features up to 30 frames per second (320times240 pixels) and has accuracy similar to a PC-based implementation. The achieved system performance is at least one order of magnitude better than a PC-based solution, a result achieved by investigating the impact of several hardware-orientated optimizations on performance, area and accuracy.

Pobreza e espaço: padrões de segregação em São Paulo

ESTE ESTUDO busca atualizar o debate sobre a segregacao urbana no Brasil, com base nos dados do Censo Demografico de 2000 e da utilizacao de Sistemas de Informacao Geografica. Sustentamos que o modelo centro-periferia e uma simplificacao generica da forma urbana, sendo a periferia de Sao Paulo heterogenea, o que acarreta importantes consequencias para as politicas publicas.

Municipalização da saúde no Brasil: diferenças regionais, poder do voto e estratégias de governo

Este artigo examina a extensao e os determinantes do processo de municipalizacao da politica de saude no Brasil, com base na analise estatistica de dados para 1.643 municipios localizados em diferentes regioes brasileiras. Inicialmente, analisa o alcance de duas dimensoes do projeto de municipalizacao da saude: a oferta municipal de servicos de atencao basica e a municipalizacao da gestao da rede hospitalar local. Em seguida, discute o impacto de distintas variaveis na decisao municipal em favor da municipalizacao: porte e localizacao do municipio, suas capacidades fiscais, as preferencias do eleitorado local, a competicao eleitoral, o contexto local para a tomada de decisao, bem como o impacto local da estrategia federal de descentralizacao.

An FPGA Implementation for a Kalman Filter with Application to Mobile Robotics

The problem of simultaneous localization and mapping has been studied by the mobile robotics scientific community over the last two decades. Most solutions for this problem are based on probabilistic theory in order to represent the uncertainty in robot perception and action. One of the most efficient probabilistic methods is the extended Kalman filter (EKF). However, the EKF demands a considerable amount of computing power and is usually processed by high-end laptops coupled to the robots. In this work, we present an implementation of the EKF targeting an embedded system based on an FPGA device. In order to improve performance, our approach combines a softcore processor with customized hardware. We present experiments with four different FPGA implementations, being the first purely based on software, the second using custom instruction logic directly connected to the processors ALU, the third using hardware accelerators connected to the processors data bus, and finally the fourth combining those two hardware/software solutions. For the experiments conducted, the results obtained with a small addition of hardware resources permitted to increase from 2times to 4times the performance of the global system.

A Floating-Point Extended Kalman Filter Implementation for Autonomous Mobile Robots

Localization and mapping are two of the most important capabilities for autonomous mobile robots and have been receiving considerable attention from the scientific computing community over the last 10 years. One of the most efficient methods to address these problems is based on the use of the extended Kalman filter (EKF). The EKF simultaneously estimates a model of the environment (map) and the position of the robot based on odometric and exteroceptive sensor information. As this algorithm demands a considerable amount of computation, it is usually executed on high end PCs coupled to the robot. In this work we present an FPGA-based architecture for the EKF algorithm that is capable of processing two-dimensional maps containing up to 1.8k features at real time (14 Hz) and is two orders of magnitude more power efficient than a general purpose processor.

Clustering-Based Selection for the Exploration of Compiler Optimization Sequences

A large number of compiler optimizations are nowadays available to users. These optimizations interact with each other and with the input code in several and complex ways. The sequence of application of optimization passes can have a significant impact on the performance achieved. The effect of the optimizations is both platform and application dependent. The exhaustive exploration of all viable sequences of compiler optimizations for a given code fragment is not feasible. As this exploration is a complex and time-consuming task, several researchers have focused on Design Space Exploration (DSE) strategies both to select optimization sequences to improve the performance of each function of the application and to reduce the exploration time. In this article, we present a DSE scheme based on a clustering approach for grouping functions with similarities and exploration of a reduced search space resulting from the combination of optimizations previously suggested for the functions in each group. The identification of similarities between functions uses a data mining method that is applied to a symbolic code representation. The data mining process combines three algorithms to generate clusters: the Normalized Compression Distance, the Neighbor Joining, and a new ambiguity-based clustering algorithm. Our experiments for evaluating the effectiveness of the proposed approach address the exploration of optimization sequences in the context of the ReflectC compiler, considering 49 compilation passes while targeting a Xilinx MicroBlaze processor, and aiming at performance improvements for 51 functions and four applications. Experimental results reveal that the use of our clustering-based DSE approach achieves a significant reduction in the total exploration time of the search space (20× over a Genetic Algorithm approach) at the same time that considerable performance speedups (41% over the baseline) were obtained using the optimized codes. Additional experiments were performed considering the LLVM compiler, considering 124 compilation passes, and targeting a LEON3 processor. The results show that our approach achieved geometric mean speedups of 1.49 × , 1.32 × , and 1.24 × for the best 10, 20, and 30 functions, respectively, and a global improvement of 7% over the performance obtained when compiling with -O2.

Políticas sociais e território: uma abordagem metropolitana

Abstract: This text defends the importance of incorporating space strategies to the social politics’ project andimplementation. Facing the problems of current social politics implementation in metropolitan areas, it concludesthat the incorporation of territorial elements to social politics may make the social initiatives more effectiveand easier to implement. Key words: social politics; metropolitan space; income transfer. H AROLDO DA G AMA T ORRES E DUARDO M ARQUES , 18(4): 28-38, 2004 ste texto pretende defender o argumento de queo desenho e as estrategias de implementacao daspoliticas sociais metropolitanas tem que levar emlencia (MARQUES; TORRES, 2004). Esses elementos ne-gativos se reforcam mutuamente, criando uma espiral ne-gativa que pode dificultar as solucoes no âmbito das poli-ticas sociais existentes.Embora essa superposicao das carencias nao seja com-pleta, como considerado pela literatura sociologica urba-na dos anos 70, determinadas areas das regioes metropo-litanas brasileiras estao – de fato – muito expostas a umaintensa cumulacao de riscos e situacoes negativas, visi-veis quando analisadas com mais detalhes algumas daschamadas hiperperiferias (TORRES; MARQUES, 2002).

ARCHITECT-R: a system for reconfigurable robots design

An increasing interest in the design of mobile robots has been observed in recent years, which is mainly motivated by technological advances that may allow their application to consumer markets, in addition to industrial areas.Although sophisticated techniques have been developed, choosing the appropriate hardware-software partitioning and programming robot functions are still very complex tasks.Current approaches often involve the design and implementation of hardwired solutions, with the associated problems of a long development cycle and inflexibility.In this paper we present a framework called ARCHITECT-R, which aims to design and program specialized hardware for robots based on FPGAs. We also present the first results obtained using this framework.

Redes de apoio social no Rio de Janeiro e em São Paulo

This article analyzes egocentered networks of social support in Rio de Janeiro and Sao Paulo using data from a survey carried out in 2008. Following the results of a previous research about personal networks in Sao Paulo, we investigate the main characteristics, dynamics and conditioning factors of the networks, evidencing strong regularities along the life cycle and between social groups. Regardless of those regularities, the results indicate intense relational heterogeneity inside each social group, organized both among the poor and the non-poor by the homophily and localism of the networks, generating strong consequences for the reproduction of social inequalities.

Government, political actors and governance in urban policies in Brazil and São Paulo: concepts for a future research agenda

Public policies are produced by connections between several actors, within institutional environments and crossing organizational boundaries, but detailed analyses of the environments in which politics occur are relatively rare in Brazil. I believe the concept of governance could help to bridge this gap. However, this concept has different meanings and has been circulated in Latin America with quite confusing and cacophonic meanings. In this analytical essay, I build a definition of governance based both on local debates and the recent international literature, which can be of use to study urban policies in Brazil, going beyond government but specifying the elements under investigation. The article starts by critically discussing the uses of the concept of governance in Latin America and especially in Brazil, highlighting some of the most important problems of the existing analyses, so as to forge an alternate operational definition. I then discuss the most relevant political actors present in Brazilian urban policies and later use these elements to discuss the governance of policies regarding the production of the built environment.