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Publicações

Publicações por CSE

2018

Generalized selections for direct control in procedural buildings

Autores
Jesus, D; Patow, G; Coelho, A; Sousa, AA;

Publicação
COMPUTERS & GRAPHICS-UK

Abstract
Procedural modeling techniques reduce the effort of creating large virtual cities. However, current methodologies do not allow direct user control over the generated models. Associated with this problem, we face the additional problem related to intrinsic ambiguity existing in user selections. In this paper, we propose to address this problem by using a genetic algorithm to generalize user-provided point-and-click selections of building elements. From a few user-selected elements, the system infers new sets of elements that potentially correspond to the user's intention, including the ones manually selected. These sets are obtained by queries over the shape trees generated by the procedural rules, thus exploiting shape semantics, hierarchy and geometric properties. Our system also provides a complete selection-action paradigm that allows users to edit procedurally generated buildings without necessarily explicitly writing queries. The pairs of user selections and procedural operations (the actions) are stored in a tree-like structure, which is easily evaluated. Results show that the selection inference is capable of generating sets of shapes that closely match the user intention and queries are able to perform complex selections that would be difficult to achieve in other systems. User studies confirm this result.

2018

Multi-Temporal Analysis of Forestry and Coastal Environments Using UASs

Autores
Padua, L; Hruska, J; Bessa, J; Adao, T; Martins, LM; Goncalves, JA; Peres, E; Sousa, AMR; Castro, JP; Sousa, JJ;

Publicação
REMOTE SENSING

Abstract
Due to strong improvements and developments achieved in the last decade, it is clear that applied research using remote sensing technology such as unmanned aerial vehicles (UAVs) can provide a flexible, efficient, non-destructive, and non-invasive means of acquiring geoscientific data, especially aerial imagery. Simultaneously, there has been an exponential increase in the development of sensors and instruments that can be installed in UAV platforms. By combining the aforementioned factors, unmanned aerial system (UAS) setups composed of UAVs, sensors, and ground control stations, have been increasingly used for remote sensing applications, with growing potential and abilities. This paper's overall goal is to identify advantages and challenges related to the use of UAVs for aerial imagery acquisition in forestry and coastal environments for preservation/prevention contexts. Moreover, the importance of monitoring these environments over time will be demonstrated. To achieve these goals, two case studies using UASs were conducted. The first focuses on phytosanitary problem detection and monitoring of chestnut tree health (Padrela region, Valpacos, Portugal). The acquired high-resolution imagery allowed for the identification of tree canopy cover decline by means of multi-temporal analysis. The second case study enabled the rigorous and non-evasive registry process of topographic changes that occurred in the sandspit of Cabedelo (Douro estuary, Porto, Portugal) in different time periods. The obtained results allow us to conclude that the UAS constitutes a low-cost, rigorous, and fairly autonomous form of remote sensing technology, capable of covering large geographical areas and acquiring high precision data to aid decision support systems in forestry preservation and coastal monitoring applications. Its swift evolution makes it a potential big player in remote sensing technologies today and in the near future.

2018

Efficient heuristics for minimizing weighted sum of squared tardiness on identical parallel machines

Autores
Schaller, J; Valente, JMS;

Publicação
COMPUTERS & INDUSTRIAL ENGINEERING

Abstract
Scheduling jobs on a set of identical parallel machines using efficient heuristics when the objective is to minimize total weighted squared tardiness is considered. Two efficient heuristics and an improvement procedure are presented for the problem. These heuristics and other heuristics are tested using problem sets that represent a variety of conditions. The results show that one of the heuristics consistently performs better than the other heuristics tested. It is also shown how these heuristics can be incorporated into other procedures such as the existing Lagrangian relaxation procedure or meta-heuristics to obtain improved solutions for medium sized problems.

2018

Monitoring continuous subsidence in the Costa del Sol (Málaga province, southern Spanish coast) using ERS-1/2, Envisat, and Sentinel-1A/B SAR interferometry

Autores
Ruiz Armenteros, AM; Lazecky, M; Ruiz Constán, A; Bakon, M; Manuel Delgado, J; Sousa, JJ; Galindo Zaldívar, J; De Galdeano, CS; Caro Cuenca, M; Martos Rosillo, S; Jiménez Gavilán, P; Perissin, D;

Publicação
Procedia Computer Science

Abstract
In this paper we analyze the subsidence behavior of a coastal area in the province of Málaga (Costa del Sol), southern Spain, in the period 1992-2018 using C-band SAR interferometry. The area comprises several zones of interest where continuous deformation has happened during the analyzed period. Using SAR data from ESA's ERS-1/2, Envisat, and Sentinel-1A/B satellites, and Multi-Temporal InSAR methods we detect and monitor subsidence in highly populated and industrial areas, airport, harbor, as well as local instabilities over a railway line and a highway. In a previous work, we reported a subsidence due to intensive use of groundwater in some populated towns in the period 1992-2009 with maximum line-of-sight (LOS) rates of the order of -11 mm/yr. In this contribution, we confirm the subsidence trend. Furthermore, we detect an increase in the deformation rates for the most recent period (2014-2018), suggesting that the overexploitation of the aquifers has not ceased. © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

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

Systematic Review of the Literature, Research on Blockchain Technology as Support to the Trust Model Proposed Applied to Smart Places

Autores
Brandão, A; Mamede, HS; Gonçalves, R;

Publicação
Trends and Advances in Information Systems and Technologies - Volume 1 [WorldCIST'18, Naples, Italy, March 27-29, 2018].

Abstract
The smart places are vulnerable with corrupted or compromised data, with the false integration of new devices, and devices with firmware versions inconsistent. These risks worsen with the increasing volume and diversity of data, devices, infrastructures and users connected to the Web. The systematic review of the literature were selected 190 documents, which reveals the growing interest on the theme of blockchain technology with the publication of 14 documents in 2014 to about 100 already in 2017. The articles focused on the areas bitcoin (about 40%), IoT (about 30%), financial (about 15%), cryptocurrencies, electronic government (about 12%), smart contracts, smart cities, business (with about 10% each) and health (about 5%). This perspective confirms the generic model study data supported in blockchain technology for smart places, especially when applied to smart cities and the specific field of the mobility ecosystem, with the use of the new concepts of the application of blockchain in IoT, smart contracts and e-governance. © 2018, Springer International Publishing AG, part of Springer Nature.

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