2014
Authors
Marques, MPM; Batista de Carvalho, LAEB; Valero, R; Machado, NFL; Parker, SF;
Publication
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Abstract
The conformational preferences and hydrogen-bonding motifs of several potential chemopreventive hydroxycinnamic derivatives were determined by inelastic neutron scattering spectroscopy. The aim is to understand their recognized beneficial activity and establish reliable structure-activity relationships for these types of dietary phytochemicals. A series of phenolic acids with different hydroxyl/methoxyl ring substitution patterns were studied: trans-cinnamic, p-coumaric, m-coumaric, trans-caffeic and ferulic acids. Their INS spectra were completely assigned by theoretical calculations performed at the Density Functional Theory level, for the isolated molecule, dimeric centrosymmetric species and the solid (using plane-wave expansion approaches). Access to the low energy vibrational region of the spectra enabled the identification of particular modes associated with intermolecular hydrogen-bonding interactions, which are the determinants of the main conformational preferences and antioxidant capacity of these systems.
2013
Authors
Pinto, M; Sobreira, H; Paulo Moreira, AP; Mendonca, H; Matos, A;
Publication
MECHATRONICS
Abstract
This paper proposes a new, fast and computationally light weight methodology to pinpoint a robot in a structured scenario. The localisation algorithm performs a tracking routine to pinpoint the robot's pose as it moves in a known map, without the need for preparing the environment, with artificial landmarks or beacons. To perform such tracking routine, it is necessary to know the initial position of the vehicle. This paper describes the tracking routine and presents a solution to pinpoint that initial position in an autonomous way, using a multi-hypotheses strategy. This paper presents experimental results on the performance of the proposed method applied in two different scenarios: (1) in the Middle Size Soccer Robotic League (MSL), using artificial vision data from an omnidirectional robot and (2) in indoor environments using 3D data from a tilting Laser Range Finder of a differential drive robot (called RobVigil). This paper presents results comparing the proposed methodology and an Industrial Positioning System (the Sick NAV350), commonly used to locate Autonomous Guided Vehicles (AGVs) with a high degree of accuracy in industrial environments.
2013
Authors
Santiago, CB; Sousa, A; Reis, LP;
Publication
MACHINE VISION AND APPLICATIONS
Abstract
The sports community needs technological aid to extract accurate statistics and performance data from both practice sessions and games. To obtain such information, players must be tracked over time and their movements processed so that individual actions and team plays are simultaneously analyzed. In order to perform this analysis in an automated, formal and accurate way, the authors developed a cost conscientious processing system fed by two overhead cameras (roughly one video stream for each half-field). Players are detected by vest colors, and Fuzzy Logic is used to allow for a given color to be shared by different teams. Color models for the background and the teams are dynamic over time to make up for changes in natural lighting conditions and consequent color changes. Player tracking is further enhanced using Kalman Filtering. Some examples of the analysis, made possible by the proposed system, are shown. Results are based on videos collected during the Portuguese Handball SuperCup competition for the year 2011.
2013
Authors
Miranda, S; Reis, LP; Sousa, A;
Publication
PROCEEDINGS OF THE 2013 8TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI 2013)
Abstract
The adoption of NAO humanoid robots in the RoboCup Standard Platform League (SPL) broguht a new set of challenges on this league on the computer vision area. This paper presents a new color indexing mode and a study of the impact of the reduction of the color spectrum, to be processed on the classification, segmentation and object detection, in a NAO robot, playing on the SPL league. The experiments were performed in the context of the Portuguese Team concluding that a 21 bit look-up table may replace the current 24 bit table used.
2013
Authors
Sousa, A; Matos, R;
Publication
PROCEEDINGS OF THE 2013 8TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI 2013)
Abstract
Massification of higher education institution promotes the importance of peer education and team work as important educational tools. As such, teams frequently produce several deliverables that should be organized and evaluated throughout a given course. Some submissions should then be attributed to the team rather than the individual and searching for a given type of deliverable from a given team becomes an important concern in terms of organization and ease of usage in evaluating assignments. The course "Projeto FEUP", used as case study and surely many others benefit from an at-least partially automated production of an organized set of all deliverables from a given course in a given year - a course portfolio, a task made easier by the usage of the presented ideas and the prototype implemented in the Moodle Learning Management System. This article shows details of the implementation and the lessons learned. The prototype was tested in the mentioned test course that has about one thousand students enrolled and a course portfolio was successfully created.
2013
Authors
Lima, JL; Goncalves, JA; Costa, PG; Moreira, AP;
Publication
INTERNATIONAL JOURNAL OF ADVANCED ROBOTIC SYSTEMS
Abstract
The simulation of a robot with a high number of joints can easily become unstable. Numerical errors on the first joint of the chain are propagated to the other joints. This is a very common problem in humanoid robots. A way to plan the gait for these robots is using simulation and optimization techniques. This paper addresses a new approach to optimizing gait parameter sets using an adaptive simulated annealing optimization algorithm, combined with a new joint model that reduces its instability. The new model and the optimization are implemented in SimTwo (a developed physical robot simulator that is capable of simulating user defined robots in a three-dimensional space, since it includes a physical model based on rigid body dynamics) and results are shown that validate the approach.
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