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Publicações

Publicações por Joaquim João Sousa

2018

UAS-based photogrammetry of cultural heritage sites: a case study addressing Chapel of Espírito Santo and photogrammetric software comparison

Autores
Pádua, L; Adão, T; Hruska, J; Marques, P; Sousa, AMR; Morais, R; Lourenço, JM; Sousa, JJ; Peres, E;

Publicação
Proceedings of the International Conference on Geoinformatics and Data Analysis, ICGDA 2018, Prague, Czech Republic, April 20-22, 2018

Abstract
The cost-effectiveness of unmanned aerial systems (UAS) makes them suitable platforms to survey cultural heritage sites. Developments in photogrammetry provide methods capable to generate accurate 3D models out of 2D aerial images. Considering the involved technologies, the purpose of this paper is to document the Chapel of Espiríto Santo: a very relevant monument for Vila Real (Portugal) that is currently located at the campus of the University of Trás-os-Montes and Alto Douro. The UAS-based aerial imagery survey approach is presented along with photogrammetric process to build chapel’s 3D model. Moreover, two photogrammetric software were compared – Pix4Dmapper Pro and Agisoft Photoscan – in terms of modelling accuracy and functionalities ease of use. © 2018 Association for Computing Machinery.

2018

Unmanned Aerial Systems (UAS) for environmental applications special issue preface PREFACE

Autores
Milas, AS; Sousa, JJ; Warner, TA; Teodoro, AC; Peres, E; Goncalves, JA; Delgado Garcia, J; Bento, R; Phinn, S; Woodget, A;

Publicação
INTERNATIONAL JOURNAL OF REMOTE SENSING

Abstract

2018

Vineyard properties extraction combining UAS-based RGB imagery with elevation data

Autores
Padua, L; Marques, P; Hruska, J; Adao, T; Bessa, J; Sousa, A; Peres, E; Morais, R; Sousa, JJ;

Publicação
INTERNATIONAL JOURNAL OF REMOTE SENSING

Abstract
To differentiate between canopy and vegetation cover is particularly challenging. Nonetheless, it is pivotal in obtaining the exact crops' vegetation when using remote-sensing data. In this article, a method to automatically estimate and extract vineyards' canopy is proposed. It combines vegetation indices and digital elevation models - derived from high-resolution images, acquired using unmanned aerial vehicles - to differentiate between vines' canopy and inter-row vegetation cover. This enables the extraction of relevant information from a specific vineyard plot. The proposed method was applied to data acquired from some vineyards located in Portugal's north-eastern region, and the resulting parameters were validated. It proved to be an effective method when applied with consumer-grade sensors, carried by unmanned aerial vehicles. Moreover, it also proved to be a fast and efficient way to extract vineyard information, enabling vineyard plots mapping for precision viticulture management tasks.

2018

A rapid prototyping tool to produce 360º video-based immersive experiences enhanced with virtual/multimedia elements

Autores
Adão, T; Pádua, L; Fonseca, M; Agrellos, L; Sousa, JJ; Magalhães, L; Peres, E;

Publicação
CENTERIS 2018 - International Conference on ENTERprise Information Systems / ProjMAN 2018 - International Conference on Project MANagement / HCist 2018 - International Conference on Health and Social Care Information Systems and Technologies 2018, Lisbon, Portugal

Abstract
While the popularity of virtual reality (VR) grows in a wide range of application contexts - e.g. entertainment, training, cultural heritage and medicine -, its economic impact is expected to reach around 15bn USD, by the year of 2020. Within VR field, 360video has been sparking the interest of development and research communities. However, editing tools supporting 360panoramas are usually expensive and/or demand programming skills and/or advanced user knowledge. Besides, application approaches to quickly and intuitively set up such 360video-based VR environments complemented with diverse types of parameterizable virtual assets and multimedia elements are still hard to find. Thereby, this paper aims to propose a system specification to simply and rapidly configure immersive VR environments composed of surrounding 360video spheres that can be complemented with parameterizable multimedia contents - namely 3D models, text and spatial sound -, whose behavior can be either time-range or user-interaction dependent. Moreover, a preliminary prototype that follows a substantial part of the previously mentioned specification and implements the enhancement of 360videos with time-range dependent virtual assets is presented. Preliminary tests evaluating usability and user satisfaction were also carried out with 30 participants, from which encouraging results were achieved. © 2018 The Authors. Published by Elsevier Ltd..

2018

Potential of synthetic chalcone derivatives to prevent marine biofouling

Autores
Almeida, JR; Moreira, J; Pereira, D; Pereira, S; Antunes, J; Palmeira, A; Vasconcelos, V; Pinto, M; Correia da Silva, M; Cidade, H;

Publicação
SCIENCE OF THE TOTAL ENVIRONMENT

Abstract
Biofouling represents a major economic, environmental and health concern for which new eco-friendly solutions are needed. International legislation has restricted the use of biocidal-based antifouling coatings, and increasing efforts have been applied in the search for environmentally friendly antifouling agents. This research work deals with the assessment of the interest of a series of synthetic chalcone derivatives for antifouling applications. Sixteen chalcone derivatives were synthesized with moderate yields (38-85%). Antifouling bioactivity of these compounds was assessed at different levels of biological organization using both anti-macrofouling and anti-microfouling bioassays, namely an anti-settlement assay using mussel (Mytilus galloprovincialis) larvae, as well as marine bacteria and microalgal biofilms growth inhibition bioassays. Results showed that three compounds (11, 12, and 16) were particularly active against the settlement of mussel larvae (EC50 7.24-34.63 mu M), being compounds 12 and 16 also able to inhibit the growth of microfouling species (EC50 4.09-20.31 mu M). Moreover, the most potent compounds 12 and 16 were found to be non-toxic to the non-target species Artemia salina (<10% mortality at 25 mu M). A quantitative structure-activity relationship model predicted that descriptors describing the ability of molecules to form hydrogen bonds and encoding the shape, branching ratio and constitutional diversity of the molecule were implied in the antifouling activity against the settlement of mussel larvae. This work elucidates for the first time the relevance of synthesizing chalcone derivatives to generate new nontoxic products to prevent marine biofouling.

2018

SAR interferometrymonitoring of subsidence in a detritic basin related to water depletion in the underlying confined carbonate aquifer (Torremolinos, southern Spain)

Autores
Ruiz Constan, A; Ruiz Armenteros, AM; Martos Rosillo, S; Galindo Zaldivar, J; Lazecky, M; Garcia, M; Sousa, JJ; Sanz de Galdeano, CS; Delgado Blasco, JM; Jimenez Gavilan, P; Caro Cuenca, M; Luque Espinar, JA;

Publicação
SCIENCE OF THE TOTAL ENVIRONMENT

Abstract
This research underlines the need to improve water management policies for areas linked to confined karstic aquifers subjected to intensive exploitation, and to develop additional efforts towards monitoring their subsidence evolution. We analyze subsidence related to intensive use of groundwater in a confined karstic aquifer, through the use of the InSAR technique, by the southern coast of Spain (Costa del Sol). Carbonates are overlain by an unconfined detritic aquifer with interlayered high transmissivity rocks, in connection with the Mediterranean Sea, where the water level is rather stable. Despite this, an accumulated deformation in the line-of-sight (LOS) direction greater than -100 mm was observed by means of the ERS-1/2 (1992-2000) and Envisat 2003-2009) satellite SAR sensors. During this period, the Costa del Sol experienced a major population increase due to the expansion of the tourism industry, with the consequent increase in groundwater exploitation. The maximum LOS displacement rates recorded during both time spans are respectively -6 mm/yr and -11 mm/yr, respectively. During the entire period, there was an accumulated descent of the confined water level of 140 m, and several fluctuations of more than 80 m correlating with the subsidence trend observed for the whole area. Main sedimentary depocenters (up to 800 m), revealed by gravity prospecting, partly coincide with areas of subsidence maxima; yet ground deformation is also influenced by other factors, the main ones being the fine-grained facies distribution and rapid urbanization due to high touristic pressure.

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