Campinas, Brazil
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Bonacin R.,CTI Renato Archer | Nabuco O.F.,CTI Renato Archer | Pierozzi Junior I.,Embrapa Agricultural Informatics
Future Generation Computer Systems | Year: 2015

Agriculture is both highly dependent on water resources, and impacting on these resources. Regardless of advances in the area, the impacts of water scarcity and climatic changes on agriculture, as well as the impacts of agriculture on water resources, remain uncertain. Potentially, collaborative systems can support the management and information sharing of multifaceted and large scale data sources, providing valuable and indispensable information for research. However, these solutions rely on semantic interoperability, the construction of complex knowledge representation models, as well as information recovery. This work describes interoperability issues in the engineering process of the OntoAgroHidro, an ontology that represents knowledge about impacts of agricultural activities and climatic changes on water resources. The paper presents representative scenarios and questions, and discusses the reuse and integration of concepts using knowledge visualization techniques. Experiments on the information recovery scenario point out the potential and limitations of the OntoAgroHidro. © 2015 Elsevier B.V.


Bonacin R.,CTI Renato Archer | Nabuco O.F.,CTI Renato Archer | Pierozzi Jr. I.,Embrapa Agricultural Informatics
Proceedings of the 5th International Conference on Management of Emergent Digital EcoSystems, MEDES 2013 | Year: 2013

Water is no longer considered an unlimited resource. As a matter of fact, many studies have shown a recent increase of water scarcity. By far, the largest demand for water resources comes from agricultural activities. Various researchers from multidisciplinary fields address the impacts of agricultural activities on water resources, as well as the impacts from possible climatic changes. In this context, the Embrapa's research network AgroHidro aims to support integration and information sharing among a range of institutions and researchers. In this paper, we present the first version of a Web Ontology to represent key aspects of this problem. The objective is to provide the basis for computational mechanisms in support of knowledge sharing and recovery, e.g., semantic search, text mining and visualization techniques. The paper also discusses the reuse and integration strategies, limitations, and challenges to be faced in the ontology engineering process. © 2013 ACM.


Ponce M.A.,University of the Sea | Ramirez M.A.,Paulista University | Schipani F.,University of the Sea | Joanni E.,CTI Renato Archer | And 2 more authors.
Journal of the European Ceramic Society | Year: 2015

In this work n-type CaCu3Ti4O12 (CCTO) thick films obtained by screen printing were studied. The role of the potential barrier characteristics (height and width) was considered in order to explain the electrical behavior. The electrical response was also analyzed considering the oxygen adsorption and subsequent diffusion into the grains at temperatures higher than 280°C. Tunnel currents were also calculated taking into account the donor concentration values for films in vacuum atmosphere. © 2014.


Dos Reis J.C.,University of Campinas | Bonacin R.,CTI Renato Archer | Baranauskas M.C.C.,University of Campinas
Lecture Notes in Business Information Processing | Year: 2011

Inclusive Social Network Services (ISN) represent an opportunity for ordinary people to access information and knowledge through the Web. Such systems should provide access for all, creating situations where users' diversity is respected and the access difficulties are minimized. The use of search mechanisms has been the main way to find information in the Web. However, such mechanisms are still built through lexical-syntactical processing resulting in barriers for many users to reach correct and valuable information. In ISN all people must have the possibility of recovering information that makes sense to them. For that, search engines in ISN should take into account the meanings created, shared and used by people through the use of the system. In this paper we prospect an inclusive search mechanism for ISN grounded in Semantic Web technologies combined with Organizational Semiotics concepts and methods. The conception of the proposed solution is based on experimental results that point out how to improve search mechanisms considering aspects related to social and digital inclusion. Such proposal aims to address and promote the participatory and universal access to knowledge. © 2011 Springer-Verlag Berlin Heidelberg.


Silveira G.,CTI Renato Archer
Journal of Mathematical Imaging and Vision | Year: 2014

The fundamental task of visual tracking is considered in this work as a direct image registration problem. Direct methods refer to those that exploit the pixel intensities without intermediate steps, e.g., no extraction of image features. This article proposes new photogeometric transformation models and nonlinear optimization methods for directly registering central omnidirectional images. The proposed models ensure robustness to arbitrary illumination changes, as well as encompass all classes of projective deformations of planar objects within those images. Experimental results show that visual tracking can indeed be highly robust and accurate even for this type of vision systems. © 2012 Springer Science+Business Media New York.


Aldao C.M.,University of the Sea | Schipani F.,University of the Sea | Ponce M.A.,University of the Sea | Joanni E.,CTI Renato Archer | Williams F.J.,University of Buenos Aires
Sensors and Actuators, B: Chemical | Year: 2014

Conduction mechanisms in polycrystalline SnO2 thick sensing films were investigated by means of DC electrical resistance during heating-cooling cycles. Samples were maintained at relatively high temperatures in H2 or O2 ambient atmospheres before performing electrical measurements under vacuum or before performing XPS measurements in order to determine band bending. Results suggest that intergrains present Schottky barriers that are responsible for the observed conductivities regardless of gas pre-treatment. Oxygen diffusion modulates barrier widths affecting conductivity through tunneling transport. The electrical response to subsequent exposure to an oxygen atmosphere is consistent with our interpretation. © 2013 Elsevier B.V. All rights reserved.


Silveira G.,CTI Renato Archer
Robotics and Autonomous Systems | Year: 2014

This article investigates the problem of pose-based visual servoing whose equilibrium state is defined via a reference image. Differently from most solutions, this work directly exploits the pixel intensities without any feature extraction or matching. Intensity-based methods provide for higher accuracy and versatility. Another central idea of this work concerns the exploitation of the observability issue associated to monocular systems, which always occurs around the equilibrium. This overall framework allows for developing a family of new 3D visual servoing techniques with varying degrees of computational complexity and of prior knowledge. Importantly, they are arranged hierarchically from the simplest to the optimal ones, all in a unified scheme. Three new methods are then presented, and their closed-loop performances are experimentally assessed using a six degree-of-freedom robotic arm. As an additional contribution, these results refute the common belief that correct camera calibration and pose recovery are crucial to the accuracy of 3D visual servoing techniques. © 2014 Elsevier B.V. All rights reserved.


Silveira G.,CTI Renato Archer | Silveira G.,French Institute for Research in Computer Science and Automation | Malis E.,French Institute for Research in Computer Science and Automation
International Journal of Computer Vision | Year: 2010

The fundamental task of visual tracking is considered in this work as an incremental direct image registration problem. Direct methods refer to those that exploit the pixel intensities without resorting to image features. We propose new transformation models and optimization methods for directly and robustly registering images (including color ones) of rigid and deformable objects, all in a unified manner. We also show that widely adopted models are in fact particular cases of the proposed ones. Indeed, the proposed general models combine various classes of image warps and ensure robustness to generic lighting changes. Finally, the proposed optimization method together with the exploitation of all possible image information allow the algorithm to achieve high levels of accuracy. Extensive experiments are reported to demonstrate that visual tracking can indeed be highly accurate and robust despite deforming objects and severe illumination changes. © 2010 Springer Science+Business Media, LLC.


Silveira G.,CTI Renato Archer
Journal of Control, Automation and Electrical Systems | Year: 2013

This article considers the fundamental task of 3-D tracking as a direct image registration problem. 3-D tracking consists in continuously recovering the camera motion in the Euclidean space. Direct methods refer to those that exploit the pixel intensities without intermediate steps, e.g.; no extraction of image features. This work presents new photogeometric transformation models and nonlinear optimization methods for directly registering calibrated central omnidirectional images of planar objects. The proposed approach simultaneously reconstructs the camera motion, the planar structure, and the illumination variations so as to perform the tracking. Experimental results show that 3-D tracking can indeed be highly robust and accurate even for this type of vision systems. © 2013 Sociedade Brasileira de Automatica - SBA.


Silva Filho O.S.,CTI Renato Archer
Proceedings of the 5th International Conference on Management of Emergent Digital EcoSystems, MEDES 2013 | Year: 2013

Brazilian Government has done a strong effort to develop the Microelectronics area in Brazil. An ecosystem of communities interested to rethink the insertion of Brazil in the important market of semiconductors. Important questions should be considered in this way, such as, for instance: "What is more important to have companies manufacturing semiconductors in Brazil or to have trained workers developing IC projects? The answer for such a question maybe is both, but how to compete with Asian industries and their billionaire investments. Thus, an appropriate answer is to invest in education and also in collaborative resources to improve project management among Companies, like Design Houses. The IC-Brazil program was thought to be an ecosystem that allow following such a receipt. In fact, an education platform and creation of jobs on microelectronics set up in Brazil the last years. Additionally, the possibility of innovation during development of projects by collaborative mechanism that uses WEB bases and Colletive Inteligence concepts shows the potential of this ecosystem. Such features are discussed here. © 2013 ACM.

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