Networked control system for the guidance of a four-wheel steering agricultural robotic platform

A current trend in the agricultural area is the development of mobile robots and autonomous vehicles for precision agriculture (PA). One of the major challenges in the design of these robots is the development of the electronic architecture for the control of the devices. In a joint project among research institutions and a private company in Brazil a multifunctional robotic platform for information acquisition in PA is being designed. This platform has as main characteristics four-wheel propulsion and independent steering, adjustable width, span of 1,80m in height, diesel engine, hydraulic system, and a CAN-based networked control system (NCS). This paper presents a NCS solution for the platform guidance by the four-wheel hydraulic steering distributed control. The control strategy, centered on the robot manipulators control theory, is based on the difference between the desired and actual position and considering the angular speed of the wheels. The results demonstrate that the NCS was simple and efficient, providing suitable steering performance for the platform guidance. Even though the simplicity of the NCS solution developed, it also overcame some verified control challenges in the robot guidance system design such as the hydraulic system delay, nonlinearities in the steering actuators, and inertia in the steering system due the friction of different terrains. Copyright © 2012 Eduardo Pacincia Godoy et al.

Development of a support vector machine-based navigation system for driving a mobile robot through paths in plantations

The use of mobile robots turns out to be interesting in activities where the action of human specialist is difficult or dangerous. Mobile robots are often used for the exploration in areas of difficult access, such as rescue operations and space missions, to avoid human experts exposition to risky situations. Mobile robots are also used in agriculture for planting tasks as well as for keeping the application of pesticides within minimal amounts to mitigate environmental pollution. In this paper we present the development of a system to control the navigation of an autonomous mobile robot through tracks in plantations. Track images are used to control robot direction by preprocessing them to extract image features. Such features are then submitted to a support vector machine in order to find out the most appropriate route. The overall goal of the project to which this work is connected is to develop a real time robot control system to be embedded into a hardware platform. In this paper we report the software implementation of a support vector machine, which so far presented around 93% accuracy in predicting the appropriate route. © 2012 IEEE.

Monitoring in precision metal drilling process using multi-sensors and neural network

This paper presents a new method to estimate hole diameters and surface roughness in precision drilling processes, using coupons taken from a sandwich plate composed of a titanium alloy plate (Ti6Al4V) glued onto an aluminum alloy plate (AA 2024T3). The proposed method uses signals acquired during the cutting process by a multisensor system installed on the machine tool. These signals are mathematically treated and then used as input for an artificial neural network. After training, the neural network system is qualified to estimate the surface roughness and hole diameter based on the signals and cutting process parameters. To evaluate the system, the estimated data were compared with experimental measurements and the errors were calculated. The results proved the efficiency of the proposed method, which yielded very low or even negligible errors of the tolerances used in most industrial drilling processes. This pioneering method opens up a new field of research, showing a promising potential for development and application as an alternative monitoring method for drilling processes. © 2012 Springer-Verlag London Limited.

Age-related differences in time-limit performance and force platform-based balance measures during one-leg stance

Poor posture control has been associated with an increased risk of falls and mobility disability among older adults. This study was conducted to assess the test-retest reliability and sensitivity to group differences regarding the time-limit (TLimit) of one-leg standing and selected balance parameters obtained with a force platform in older and young adults. A secondary purpose was to assess the relationship between TLimit and these balance parameters. Twenty-eight healthy older adults (age: 69±5years) and thirty young adults (age: 21±4years) participated in this study. Two one-leg stance tasks were performed: (1) three trials of 30s maximum and (2) one TLimit trial. The following balance parameters were computed: center of pressure area, RMS sway amplitude, and mean velocity and mean frequency in both the anterio-posterior and medio-lateral directions. All balance parameters obtained with the force platform as well as the TLimit variable were sensitive to differences in balance performance between older and young adults. The test-retest reliability of these measures was found to be acceptable (ICC: 0.40-0.85), with better ICC scores observed for mean velocity and mean frequency in the older group. Pearson correlations coefficients (r) between balance parameters and TLimit ranged from -0.16 to -0.54. These results add to the current literature that can be used in the development of measurement tools for evaluating balance in older and young adults. © 2013 Elsevier Ltd.

Pré-regulador retificador boost com controle digital por valores médios, para sistema de iluminação fluorescente multi-lâmpadas, utilizando dispositivo FPGA e VHDL

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo multi-instrumental do processo de desintegração de comprimidos envolvendo três classes de desintegrantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Multi-dimensional Review of Uruguay. Volume 1: initial assessment

Includes bibliography.

Estudio Multi-dimensional de Uruguay. Volumen 1: evaluación inicial

Incluye bibliografía.

Regional review and appraisal of implementation of the Beijing Declaration and Platform for Action and the outcome of the twenty-third special session of the General Assembly (2000) in Latin American and Caribbean countries

This report indicates the main advances of the past 20 years based on the information provided by the region’s countries on implementation of the Beijing Declaration and Platform for Action, in response to the recommendations made in the final document of the twenty-third special session of the General Assembly (2000) for the regional and global reviews that would take place in 2015, on the twentieth anniversary of the Beijing Conference (Beijing+20). The subregional report on the Caribbean (ECLAC, 2014c) has also been taken into account, which includes data from the country gender assessments prepared by the Caribbean Development Bank, the country poverty assessments and information provided by the Caribbean Community (CARICOM).

Development Paths In The Caribbean

This study analyzes the patterns of development in the Caribbean and gives particular focus to the challenges to and opportunities for sustainable development. The study is divided into two parts. The first part of the study examines trajectories for development in the Caribbean, while the second addresses the relationship between competition and integration.1 The significant development gains attained since independence have been threatened in the last decade. Slowing productivity growth, rising debt, increasing crime and social dislocation in recent years have adversely affected growth in per capita income and social welfare. The study therefore calls on policy makers to promote dynamic drivers of growth and development in the region. The key requirement in this regard, is the need to strengthen import productivity,2 or the efficiency with which the region uses foreign exchange. This can be done by producing and exporting more high-value services such as education and the output of the creative industries. The sub-region also needs to strengthen its systems of governance by providing more opportunities for citizens to participate in decision making. In addition, the region needs to address the inherent relationship between competition and integration by developing improved systems to cushion the negative impacts on weaker members of the integration arrangement. These could include a more robust development fund and capacity building to enable losers to benefit from regional trade and investment. However, regional integration should provide a platform for moving up the value chain, through research and development and innovation to produce more competitive exports.

Caribbean synthesis review and appraisal report in the context of the 15th anniversay of the adoptaton of the Beijing declaration and platform for action

The report is a summary based on information received by ECLAC from the eight English-speaking Caribbean countries of Barbados, Belize, the Cayman Islands, the Commonwealth of Dominica, Jamaica, Suriname, Saint Vincent and the Grenadines and Trinidad and Tobago in response to the questionnaire to governments on the Implementation of the Beijing Declaration and Platform for Action (1995) and the Outcome of the Twenty-Third Special Session of the General Assembly (2000). The report is therefore set in the context of the regional review and appraisals of the fifteenth anniversary of the adoption of the Beijing Declaration and Platform for Action in 2010. This Executive Summary highlights the achievements and the challenges for the Caribbean subregion in the progress towards implementation of the Beijing Platform of Action.

Processo de desenvolvimento e coordenação de projetos na construção civil: um estudo multi-caso em empresas de Belém (PA)

Este trabalho faz uma reflexão sobre a coordenação de projetos na indústria da construção de edifícios, identifica as etapas do processo de projeto, aponta a participação da equipe de projeto, durante as atividades de coordenação, apresenta a atuação do coordenador de projetos e sistematiza os procedimentos de controle e retroalimentação. Para desenvolver a pesquisa, foram realizados estudos bibliográficos sobre a Gestão e Coordenação de Projetos, no desenvolvimento do processo de projeto na construção civil. Também foram feitos estudos de campo, envolvendo 10 empresas de construção civil na área urbana da cidade de Belém-PA, com atuação nos mercados de incorporação e/ou construção de obras privadas ou públicas, visando propor diretrizes da gestão de projetos, integrada ao processo de desenvolvimento e coordenação dos mesmos. Como resultado, vimos que 100% das empresas pesquisadas afirmou que o planejamento técnico do projeto é dividido por etapas, conforme apresentação de fluxogramas distintos. 77,77% das empresas em questão respondeu que realiza a coordenação de projetos através de reuniões com as equipes responsáveis. Também 100% das empresas aponta como funções do coordenador de projetos a compatibilização entre os projetos e a manutenção do fluxo de informações entre os projetistas. Em 88,88% das empresas, foi possível observar que a retroalimentação do projeto acontece através do controle por meio de check list e planilhas. Por fim, são desenvolvidas e apresentadas diretrizes para aplicação da coordenação de projeto, como forma de melhorar o desempenho do desenvolvimento do processo de projeto e a execução dos edifícios, com a valorização do projeto e conseqüente economia de recursos, tempo e dinheiro, evitando erros, desperdício e trabalho nos empreendimentos.

A socio-environmental development programme in action in Brazilian Amazonia

This paper deals with the process of scaling up and scaling down grassroots demands through a state-sponsored socio-environmental development programme in Brazilian Amazonia called Proambiente (Pro-environment). The paper attempts to understand the links between the three different levels of the programme actions: the macro (federal government), intermediate (NGOs), and local (community) levels. The central paper s issue is to understand how a state-sponsored socio-environmental development programme interacts with and impacts local communities. The theoretical paper s framework involves the approaches of participatory development and governance. The methodology is based on three levels of qualitative analysis (macro-, intermediary- and local-level). The paper (a) describes the trajectory of the Proambiente and the process of scaling up communities demands; (b) reveals contradictions within the Proambiente implementation; and (c) debates the impacts of the programme actions at local level. The paper reveals that once the state encompasses local people s demands and creates a development programme, the development model absorbs multi-actor interests that change local people s proposals. It also shows that the challenge facing a socio-environmental development programme like the Proambiente is to find a balance between production and conservation aims.

Sistema multiagente web semântico para gestão de conteúdos educacionais

Pós-graduação em Ciência da Computação - IBILCE