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Publicações

Publicações por Joaquim João Sousa

2014

Proposal of an Information System for an Adaptive Mixed Reality System for Archaeological Sites

Autores
Magalhaes, LG; Sousa, JJ; Bento, R; Adao, T; Pereira, F; Filipe, V; Peres, E;

Publicação
CENTERIS 2014 - CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS / PROJMAN 2014 - INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT / HCIST 2014 - INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES

Abstract
The use of Augmented Reality (AR) techniques to visualize virtual archaeological sites is neither a new or recent issue. In those approaches the virtual models are only visualized using the existent in situ illumination, which does not allow a visitor to have a similar visual experience to that which he would have at the time the structures were built. In Augmented Virtuality (AV) approaches the virtual world prevails, which is augmented with information from the real world, which allows a better control over the parameters of the Mixed Reality (MR) environment created. In some cases, there is the need to use both approaches (AR or AV), depending on some context conditions. This paper proposes an architecture and an information system for an adaptive MR system which main goal is to visualize in situ virtual reconstructions of archaeological sites that are seamlessly merged with the real scene. In this context, a new adaptive methodology will be defined to manage the level of mixing between the real and the virtual scene, identifying in each instant the most proper approach to use (AR or AV), as well as defining the way how transitions between approaches are made. (C) 2014 The Authors. Published by Elsevier Ltd.

2016

Multi-temporal InSAR evidence of ground subsidence induced by groundwater withdrawal: the Montellano aquifer (SW Spain)

Autores
Ruiz Constan, A; Ruiz Armenteros, AM; Lamas Fernandez, F; Martos Rosillo, S; Manuel Delgado, JM; Bekaer, DPS; Joao Sousa, JJ; Gil, AJ; Caro Cuenca, MC; Hanssen, RF; Galindo Zaldivar, J; Sanz de Galdeano, CS;

Publicação
ENVIRONMENTAL EARTH SCIENCES

Abstract
This study uses the InSAR technique to analyse ground subsidence due to intensive exploitation of an aquifer for agricultural and urban purposes in the Montellano town (SW Spain). The detailed deformation maps clearly show that the spatial and temporal extent of subsidence is controlled by piezometric level fluctuations and the thickness of compressible sediments. The total vertical displacement measured with multi-temporal InSAR, between 1992 and 2010, is 33 mm that corresponds with a decrease of 43 m in the groundwater level. This technique allows monitoring the evolution of settlement related to water level fall in an area where subsidence has not yet been reported by population or authorities through infrastructure damages and to discuss the effect of the aquifer recovery. This information is, therefore, valuable for implementing effective groundwater management schemes and land-use planning and to propose new building regulations in the most affected areas.

2017

UAS, sensors, and data processing in agroforestry: a review towards practical applications

Autores
Pádua, L; Vanko, J; Hruska, J; Adao, T; Sousa, JJ; Peres, E; Morais, R;

Publicação
INTERNATIONAL JOURNAL OF REMOTE SENSING

Abstract
The aim of this study is twofold: first, to present a survey of the actual and most advanced methods related to the use of unmanned aerial systems (UASs) that emerged in the past few years due to the technological advancements that allowed the miniaturization of components, leading to the availability of small-sized unmanned aerial vehicles (UAVs) equipped with Global Navigation Satellite Systems (GNSS) and high quality and cost-effective sensors; second, to advice the target audience - mostly farmers and foresters - how to choose the appropriate UAV and imaging sensor, as well as suitable approaches to get the expected and needed results of using technological tools to extract valuable information about agroforestry systems and its dynamics, according to their parcels' size and crop's types. Following this goal, this work goes beyond a survey regarding UAS and their applications, already made by several authors. It also provides recommendations on how to choose both the best sensor and UAV, in according with the required application. Moreover, it presents what can be done with the acquired sensors' data through theuse of methods, procedures, algorithms and arithmetic operations. Finally, some recent applications in the agroforestry research area are presented, regarding the main goal of each analysed studies, the used UAV, sensors, and the data processing stage to reach conclusions.

2015

viStaMPS: The InSAR collaborative project

Autores
Sousa, JJ; Guimarães, P; Sousa, A; Ruiz Armenteros, AM; Patrício, G; Magalhães, L;

Publicação
European Space Agency, (Special Publication) ESA SP

Abstract
The viStaMPS software is a collaborative scientific project that was created with three major purposes: (1) facilitate the usage by users non familiar with the specificities of the programming language that supports StaMPS; (2) implement several visualization tasks not available in the StaMPS standard approach (avoiding that each user develop its own code for visualization and interpretation purposes) and (3) create a collaborative research project, continuously under development counting on the dynamism of its users to improve and/or add new features.

2013

Multi-temporal SAR interferometry reveals acceleration of bridge sinking before collapse

Autores
Sousa, JJ; Bastos, L;

Publicação
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES

Abstract
On the night of 4 March 2001, at Entre-os-Rios (Northern Portugal), the Hintze Ribeiro centennial bridge collapsed killing 59 people traveling in a bus and three cars that were crossing the Douro River. According to the national authorities, the collapse was due to two decades of uncontrolled sand extraction which compromised the stability of the bridge's pillars, together with underestimating the warnings from divers and technicians. In this work we do not intend to corroborate or contradict the official version of the accident's causes, but only demonstrate the potential of Multi-Temporal Interferometric techniques for detection and monitoring of deformations in structures such as bridges, and consequently the usefulness of the derived information in some type of early warning system to help prevent new catastrophic events. Based on the analysis of 52 ERS-1/2 covering the period from May 1995 to the fatal occurrence, we were able to detect significant movements, reaching rates of 20mmyr-1, in the section of the bridge that fell into the Douro River, which are obvious signs of the bridge's instability. These promising results demonstrate that with the new high-resolution synthetic aperture radar satellite scenes it is possible to develop interferometric based methodologies for structural health monitoring.

2014

Potential of Multi-Temporal InSAR Techniques for Bridges and Dams Monitoring

Autores
Sousa, JJ; Hlavacova, I; Bakon, M; Lazecky, M; Patricio, G; Guimaraes, P; Ruiz, AM; Bastos, L; Sousa, A; Bento, R;

Publicação
CENTERIS 2014 - CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS / PROJMAN 2014 - INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT / HCIST 2014 - INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES

Abstract
The aim of this paper is twofold. Firstly, to present a survey of the actual and most advanced methods for man-made structures monitoring, more specifically dams and bridges. Theoretical and technical aspects of these methodologies are presented and discussed focusing on innovative inspection methods and on the opportunities that could deliver. Secondly, to identify the opportunities that could potentially improve the inspections and maintenance processes, being the satellite-based monitoring, using radar imagery, recognized as viable source of independent information products that may be used to remotely monitor the health of these specific man-made structures. By applying Multi-temporal InSAR processing techniques to a series of radar images over the same region, it is possible to detect vertical movements of structure systems on the ground in the millimeter range, and therefore, identify abnormal or excessive movement indicating potential problems requiring detailed ground investigation. In this paper it is clearly demonstrated that with the new high-resolution synthetic aperture radar satellites scenes, InSAR technology may be particular useful as hot spot indicator of relative deformations structures over large areas, making possible to develop interferometric based methodologies for structural health monitoring. From a technological standpoint, this approach represents a substantial evolution over the current state-of-the-art. (C) 2014 The Authors. Published by Elsevier Ltd.

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