2008
Autores
Sabugosa Madeira, B; Ribeiro, H; Cunha, M; Abreu, I;
Publicação
JOURNAL OF APICULTURAL RESEARCH
Abstract
Plantain (Plantago spp.) is generally considered to be an anemophilous plant that produces pollen of low nutritional value to bees. Between April and September during 2002 and 2003, in two regions in northwestern Portugal, we studied both the pollen collected by honey bee colonies and airborne pollen. Plantain pollen collection by honey bees was observed only in three different periods, despite its continuous presence in the air. This behaviour was related to the beginning and ending of flowering of the honey bee's main nutritional pollen sources, with no other factor seemingly influencing the temporal collecting patterns. The collection of Plantago spp. pollen was observed in the gaps between the flowering of Eucalyptus spp., chestnut (Castanea sativa), wild blackberry (Rubus spp.) and heaths (Ericaceae family). The results suggest that pollen of Plantago species seems to be used by honey bees as a substitute for other more nutritious pollen types and is collected only as a supplementary source. The temporal patterns of Plantago pollen collection by honey bees could therefore be used as a valuable ecological indicator of periods with low availability of highly nutritious pollen sources.
2008
Autores
Marcal, ARS; Cunha, M;
Publicação
TRANSACTIONS OF THE ASABE
Abstract
A fully automatic methodology based on image processing is proposed to evaluate the quality of spray application sampled by water-sensitive papers (WSP). The methods proposed permit a computation of the fraction of spray coverage, an evaluation of the homogeneity of the spray spatial spread at various scales and directions, and extraction of stain and droplet size range and distribution. This allows the number of droplets per unit area and the standard droplet size spectra factors to be computed. The methods were tested with a number of test samples scanned at different resolutions, proving to be effective in situations where there is high spray coverage in the WSP, thus with considerable overlap between stains. The most suitable scanning resolution was found to be 600 dpi. The results obtained by the image processing methods were successfully compared with a manual (visual) counting of stains in a test sample.
2007
Autores
Carvalho Goncalves, JA; Portela Pinheiro, PH; Magalhaes Lima, JLS; Gomes Da Costa, PJC;
Publicação
Revista Iberoamericana de Tecnologias del Aprendizaje
Abstract
Soccer was the original motivation for Robocup. Besides being a very popular sport worldwide, soccer brings up a set of challenges for researchers while attracting people to the event, promoting robotics among students, researchers and general public. RoboCup chose to use soccer game as a central topic of research, aiming at innovations to be applied for socially significant problems and industries. This paper describes the implementation of a system similar to the used by the teams participating in the Robocup small size league (SLL). The system, developed in Object Pascal, allows real time localization and control of an omnidirectional mobile robot. The objective of this paper is to be an introductory tutorial for Robocup soccer games, focusing in the base topics real time localization and control. © IEEE.
2007
Autores
Conceicao, AS; Oliveira, HP; e Silva, AS; Oliveira, D; Moreira, AP;
Publicação
2007 IEEE INTERNATIONAL SYMPOSIUM ON INDUSTRIAL ELECTRONICS, PROCEEDINGS, VOLS 1-8
Abstract
This paper presents a nonlinear model based predictive controller (NMPC) for trajectory tracking of a mobile robot. Methods of numerical optimization to perform real time nonlinear minimization of the cost function are used. The cost function penalizes the robot position error, the robot orientation angle error and the control effort. Experimental results of the trajectories following and the performance of the methods of optimization are presented.
2007
Autores
Martins, A; Almeida, J; Almeida, C; Figueiredo, A; Santos, F; Bento, D; Silva, H; Silva, E;
Publicação
IFAC Proceedings Volumes (IFAC-PapersOnline)
Abstract
In this work a forest fire detection solution using small autonomous aerial vehicles is proposed. The FALCOS unmanned aerial vehicle developed for remote-monitoring purposes is described. This is a small size UAV with onboard vision processing and autonomous flight capabilities. A set of custom developed navigation sensors was developed for the vehicle. Fire detection is performed through the use of low cost digital cameras and near-infrared sensors. Test results for navigation and ignition detection in real scenario are presented.
2007
Autores
Silva, MF; Machado, JAT;
Publicação
JOURNAL OF VIBRATION AND CONTROL
Abstract
The objective of this paper is to present the evolution and the state-of-the-art in the area of legged locomotion systems. In a first phase different possibilities for implementing mobile robots are discussed, namely the case of artificial legged locomotion systems, while emphasizing their advantages and limitations. In a second phase a historical overview of the evolution of these systems is presented, bearing in mind several particular cases often considered as milestones of technological and scientific progress. After this historical timeline, some of the present-day systems are examined and their performance is analyzed. In a third phase the major areas of research and development that are presently being followed in the construction of legged robots are pointed out. Finally, some still unsolved problems that remain defying robotics research, are also addressed.
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