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Lourenco A.,New University of Lisbon | Marques F.,New University of Lisbon | Santana P.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Santana P.,Telecommunications Institute of Portugal | Barata J.,New University of Lisbon
2014 IEEE International Conference on Robotics and Biomimetics, IEEE ROBIO 2014 | Year: 2014

This paper presents a method for 3-D based obstacle detection on autonomous vehicles navigating in vegetated environments. At its core three different methods processing the surrounding occupancy, taken at separate stages and volumetric resolutions, are combined to a reliable and broad solution. Geometric relationships are evaluated at a coarse, yet robust, volumetric representation to form an initial assessment on obstacles. Then, a more careful evaluation takes place, at finer resolutions, to determine which obstacles are part of the scene's vegetation, thus not real obstacles. Field experiments are shown to validate the method's applicability on two different autonomous vehicles: a water surface robot and a terrestrial four-wheeled one. © 2014 IEEE.


Deusdado P.,INTROSYS SA | Pinto E.,New University of Lisbon | Guedes M.,INTROSYS SA | Marques F.,New University of Lisbon | And 12 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

This paper presents an aerial-ground field robotic team, designed to collect and transport soil and biota samples in estuarine mudflats. The robotic system has been devised so that its sampling and storage capabilities are suited for radionuclides and heavy metals environmental monitoring. Automating these time-consuming and physically demanding tasks is expected to positively impact both their scope and frequency. The success of an environmental monitoring study heavily depends on the statistical significance and accuracy of the sampling procedures, which most often require frequent human intervention. The bird’s-eye viewprovided by the aerial vehicle aims at supporting remote mission specification and execution monitoring. This paper also proposes a preliminary experimental protocol tailored to exploit the capabilities offered by the robotic system. Preliminary field trials in real estuarine mudflats show the ability of the robotic system to successfully extract and transport soil samples for offline analysis. © Springer International Publishing Switzerland 2016.


Silva J.,New University of Lisbon | Mendonca R.,New University of Lisbon | Marques F.,New University of Lisbon | Rodrigues P.,New University of Lisbon | And 3 more authors.
2014 IEEE International Conference on Robotics and Biomimetics, IEEE ROBIO 2014 | Year: 2014

This paper presents a method for vision-based landing of a multirotor unmanned aerial vehicle (UAV) on an autonomous surface vehicle (ASV) equipped with a helipad. The method includes a mechanism for helipad behavioural search when outside the UAV's field of view, a learning saliency-based mechanism for visual tracking the helipad, and a cooperative strategy for the final vision-based landing phase. Learning how to track the helipad from above occurs during takeoff and cooperation results from having the ASV tracking the UAV for assisting its landing. A set of experimental results with both simulated and physical robots show the feasibility of the presented method. © 2014 IEEE.


Amaral V.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Marques F.,New University of Lisbon | Lourenco A.,New University of Lisbon | Barata J.,New University of Lisbon | And 2 more authors.
Journal of Sensors | Year: 2016

This paper presents a system for obstacle detection in railway level crossings from 3D point clouds acquired with tilting 2D laser scanners. Although large obstacles in railway level crossings are detectable with current solutions, the detection of small obstacles remains an open problem. By relying on a tilting laser scanner, the proposed system is able to acquire highly dense and accurate point clouds, enabling the detection of small obstacles, like rocks laying near the rail. During an offline training phase, the system learns a background model of the level crossing from a set of point clouds. Then, online, obstacles are detected as occupied space contrasting with the background model. To reduce the need for manual on-site calibration, the system automatically estimates the pose of the level crossing and railway with respect to the laser scanner. Experimental results show the ability of the system to successfully perform on a set of 41 point clouds acquired in an operational one-lane level crossing. © 2016 Vítor Amaral et al.


Pinto E.,New University of Lisbon | Deusdado P.,INTROSYS SA | Marques F.,New University of Lisbon | Lourenco A.,New University of Lisbon | And 4 more authors.
ISMA 2015 - 10th International Symposium on Mechatronics and its Applications | Year: 2015

This paper presents a multi-core processing solution for ROS-based service robots. The power management together with the control and availability of the processing resources are supervised by a custom-made Power Management Board (PMB) based on a Digital Signal Processor (DSP) micro controller, implementing a Health and Usage Monitoring System (HUMS). The proposed architecture also allows for the PMB to control the most critical robot functions in case of low battery conditions or impossibility of performing energy harvesting, thus extending the lifespan of the robot. All PMB data is recorded on a SD card so as to allow offline analyses of the robotic mission and, thus, support subsequent maintenance activities. Two different implementations of the proposed system have been fielded in two Multi-Robot Systems (MRS) for environmental monitoring, covering aerial, water surface, and wheeled ground vehicles. An additional implementation of the architecture is currently being deployed on an industrial autonomous logistics robot. These three implementations are presented and discussed. © 2015 IEEE.


Gomes P.,New University of Lisbon | Santana P.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Barata J.,New University of Lisbon
International Journal of Advanced Robotic Systems | Year: 2014

This paper presents a vision-based method for fire detection from fixed surveillance smart cameras. The method integrates several well-known techniques properly adapted to cope with the challenges related to the actual deployment of the vision system. Concretely, background subtraction is performed with a context-based learning mechanism so as to attain higher accuracy and robustness. The computational cost of a frequency analysis of potential fire regions is reduced by means of focusing its operation with an attentive mechanism. For fast discrimination between fire regions and fire-coloured moving objects, a new colour-based model of fire's appearance and a new wavelet-based model of fire's frequency signature are proposed. To reduce the false alarm rate due to the presence of fire-coloured moving objects, the category and behaviour of each moving object is taken into account in the decision-making. To estimate the expected object's size in the image plane and to generate geo-referenced alarms, the camera-world mapping is approximated with a GPS-based calibration process. Experimental results demonstrate the ability of the proposed method to detect fires with an average success rate of 93.1% at a processing rate of 10 Hz, which is often sufficient for real-life applications. © 2014 The Author(s). Licensee InTech.


Pinheiro P.,Iscte Instituto Universitario Of Lisbon | Aparicio M.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Aparicio M.,New University of Lisbon | Costa C.,Iscte Instituto Universitario Of Lisbon Iscte Iul
ACM International Conference Proceeding Series | Year: 2014

The purpose of this paper is to verify the factors that influence acceptance it in the context of cloud computing systems adoption. This study presents the theoretical factors, which influence the acceptance of new information systems. The first part contains a literature review on Cloud Computing. We describe the Technology Acceptance Model, applied with research hypothesis for an empirical study. The paper presents an empirical study conducted in a user dimension. Many users, professional and personal answered to a questionnaire from various fields. In this study, we concluded that perceived usefulness has a positive impact in the intention of using cloud computer systems, among other conclusions. © 2014 ACM.


PubMed | Mundiservicos Consulting, Iscte Instituto Universitario Of Lisbon Iscte Iul and New University of Lisbon
Type: Journal Article | Journal: Psychological reports | Year: 2016

Based on Szulanskis knowledge transfer model, this study examined how the communicational, motivational, and sharing of understanding variables influenced knowledge transfer and change processes in small- and medium-sized enterprises, particularly under projects developed by funded programs. The sample comprised 144 entrepreneurs, mostly male (65.3%) and mostly ages 35 to 45 years (40.3%), who filled an online questionnaire measuring the variables of sharing of understanding, motivation, communication encoding competencies, source credibility, knowledge transfer, and organizational change. Data were collected between 2011 and 2012 and measured the relationship between clients and consultants working in a Portuguese small- and medium-sized enterprise-oriented action learning program. To test the hypotheses, structural equation modeling was conducted to identify the antecedents of sharing of understanding, motivational, and communicational variables, which were positively correlated with the knowledge transfer between consultants and clients. This transfer was also positively correlated with organizational change. Overall, the study provides important considerations for practitioners and academicians and establishes new avenues for future studies concerning the issues of consultant-client relationship and the efficacy of Government-funded programs designed to improve performance of small- and medium-sized enterprises.


Fulane O.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Unico B.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Alturas B.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Lage E.,Iscte Instituto Universitario Of Lisbon Iscte Iul
Iberian Conference on Information Systems and Technologies, CISTI | Year: 2012

This paper seeks to identify the critical factors for implementing ERP systems and the difficulties of implementation in two banks in Mozambique. For this purpose a qualitative study was conducted in two banks, using semi structured interviews. As motivators for the implementation were identified external factors (such as regulatory changes) and internal factors (such as problems of integration of internal systems and inflexible reporting). The main difficulties mentioned were lack of coordination at the level of information technology, lack of resources and skills and lack of understanding by users. © 2012 AISTI.


Monteiro D.,Iscte Instituto Universitario Of Lisbon Iscte Iul | Alturas B.,Iscte Instituto Universitario Of Lisbon Iscte Iul
Iberian Conference on Information Systems and Technologies, CISTI | Year: 2012

This article seeks to determine what factors influence or constrain the adoption and use of online recruiting tools. How can encapsulate and that new implementations or improvements can be made. We studied the two perspectives involved in the process, ie, candidate and recruiter. To collect the data, and based on the Portuguese labor market, we conducted an exploratory study conducted through a set of semi-structured interviews with a group of users type. © 2012 AISTI.

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