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Browsing ESTG - Capítulos de livros by Field of Science and Technology (FOS) "Engenharia e Tecnologia"
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- 3D Video Representation and CodingPublication . Faria, Sergio M.M.; Debono, Carl J.; Nunes, Paulo; M. M. Rodrigues, NunoThe technologies which allow an immersive user experience in 3D environments are rapidly evolving and new services have emerged in various fields of application. Most of these services require the use of 3D video, combined with appropriate display systems. As a consequence, research and development in 3D video continues attracting sustained interest. While stereoscopic viewing is already widely spread, namely in TV and gaming, new displays and applications, such as FTV (Free viewpoint TV), require the use of a larger number of views. Hence, the multiview video format was considered, which uses N views, corresponding to the images captured by N cameras (either real or virtual), with a controlled spatial arrangement. In order to avoid a linear escalation of the bitrate, associated with the use of multiple views, video-plus-depth formats have been proposed. A small number of texture and depth video sequences are used to synthesize intermediate texture views at a different space position, through a depth-image-based rendering (DIBR) technique. This technology allows the use of advanced stereoscopic display processing and to improve support for high-quality autostereoscopic multiview displays. In order to provide a true 3D content and fatigue-free 3D visualization, holoscopic imaging has been introduced as an acquisition and display solution. However, efficient coding schemes for this particular type of content are needed to enable proper storage and delivery of the large amount of data involved in these systems, which is also addressed in this chapter.
- Augmented Reality and 3D Technologies: Mapping Case Studies in EducationPublication . Cardoso, Teresa; Coimbra, Teresa; Mateus, ArturLearning anywhere, anytime is becoming ever more a daily routine, due to the increasing and recent growth of information and communication technologies. In the last 5 years, their key characteristic and specifically in the use of mobile equipment and software have been their portability, mobility, and network access. The technological development, including software applications available for the implementation of three-dimensional contents, has been following this trend. Hence, it is important to know whether and how these threedimensional contents are being integrated in educational situations, namely, regarding augmented reality and mobile learning. Thus, a synthesis of Portuguese and international research works and case studies on the use of threedimensional augmented reality is chronologically presented along with the evolution of information and communication technologies. The main goal of this knowledge mapping is to contribute to the state of the art in threedimensional augmented reality technologies in education. In addition, it is aimed at framing the creation and implementation of three-dimensional content in higher education, specifically in the field of mathematics. © Springer-Verlag Berlin Heidelberg 2015.
- Characterization of the Dagorda Claystone in Leiria, Portugal, Based on Laboratory TestsPublication . Veiga, A.; Quinta-Ferreira, M.The Hetangian Dagorda claystone Formation occupies the core of a diapir outcropping in part of the city of Leiria, exhibiting a complex geological structure. The geological and geotechnical characterization is presented based in field observation and laboratory tests allowing to conclude that the Dagorda clay soils exhibit an unfavourable behaviour for urban occupation, due to the presence of expansive clay minerals. When partially saturated these soils can lead to cracking of walls and floors, or even to endanger the stability of buildings, if they have not been strengthened to resist to expansive soil. The presence of soluble minerals, mainly gypsum and seldom halite, can allow the formation of voids and eventually the deformation or collapse of the ground. Suitable safety procedures, in order to prevent hazards should be used.
- Complexity Analysis of HEVC Decoding for Multi-core PlatformsPublication . Cordeiro, Paulo J.; Assunção, Pedro; Gómez-Pulido, Juan A.The High Efficiency Video Coding (HEVC) is the latest standard, providing the same quality as its predecessor H.264/AVC at about half of the bit-rate. An increasing demand for higher quality and better resolutions in mobile applications require the use of more efficient video codecs, but the high computational complexity of HEVC poses problems to resource-constrained devices and portable equipment with limited batery-life. Despite the fact that video coding complexity is much higher than decoding, in most user devices, video decoding is used more often than encoding, thus particular attention must also be given to HEVC decoders. This paper presents an experimental study and complexity analysis of the HEVC decoder’s behaviour when decoding 4k ultra high definition (UHD) and HD video sequences on multi-core platforms, such as those of the most recent mobile devices. It is shown that when tile partitioning is used, different tiles have different decoding complexities. These findings are relevant for devising dynamic tile partitioning schemes capable of achieving load balancing in video decoders running on multi-core platforms.
- Deconvolution of X-ray Diffraction Profiles Using Genetic Algorithms and Differential EvolutionPublication . Santos, Sidolina P.; Gomez-Pulido, Juan A.; Sanchez-Bajo, FlorentinoSome optimization problems arise when X-ray diffraction profiles are used to determine the microcrystalline characteristics of materials, like the detection of diffraction peaks and the deconvolution process necessary to obtain the pure diffraction profile. After applying the genetic algorithms to solve satisfactorily the first problem, in this work we propose two evolutionary algorithms to solve the deconvolution problem. This optimization problem targets the objective of obtaining the profile that contains the microstructural characteristics of a material from the experimental data and instrumental effects. This is a complex problem, ill-conditioned, since not only there are many possible solutions, but also some of them lack physical sense. In order to avoid such circumstance, the regularization techniques are used, where the optimization of some of their parameters by means of intelligent computing permits to obtain the optimal solutions of the problem.
- DOTS: Drift Oriented Tool SystemPublication . Antunes, Mário; Costa, Joana; Silva, Catarina; Bernardete RibeiroDrift is a given in most machine learning applications. The idea that models must accommodate for changes, and thus be dynamic, is ubiquitous. Current challenges include temporal data streams, drift and non-stationary scenarios, often with text data, whether in social networks or in business systems. There are multiple drift patterns types: concepts that appear and disappear suddenly, recurrently, or even gradually or incrementally. Researchers strive to propose and test algorithms and techniques to deal with drift in text classification, but it is difficult to find adequate benchmarks in such dynamic environments. In this paper we present DOTS, Drift Oriented Tool System, a framework that allows for the definition and generation of text-based datasets where drift characteristics can be thoroughly defined, implemented and tested. The usefulness of DOTS is presented using a Twitter stream case study. DOTS is used to define datasets and test the effectiveness of using different document representation in a Twitter scenario. Results show the potential of DOTS in machine learning research.
- eCrash: a Genetic Programming-Based Testing Tool for Object-Oriented SoftwarePublication . Ribeiro, José Carlos Bregieiro; Nogueira, Ana Filipa; Vega, Francisco Fernández de; Zenha-Rela, Mário AlbertoThis paper describes the methodology, architecture and features of the eCrash framework, a Java-based tool which employs Strongly-Typed Genetic Programming to automate the generation of test data for the structural unit testing of Object-Oriented programs. The application of Evolutionary Algorithms to Test Data generation is often referred to as Evolutionary Testing. eCrash implements an Evolutionary Testing strategy developed with three major purposes: improving the level of performance and automation of the Software Testing process; minimising the interference of the tool’s users on the Test Object analysis to a minimum; and mitigating the impact of users decisions in the Test Data generation process.
- Electrospinning for Medical ApplicationsPublication . Song, Wenhui; Mitchell, Geoffrey R.; Burugapalli, KrishnaThere is a natural connection between a variety of electrospun fibres and biomedical applications. The most commonly quoted application of electrospun fibres is their use as scaffolds in tissue engineering for regenerative medicine. There are also many other applications, which include drug delivery systems, membrane systems and analytical functionality. This chapter identifies the key challenges in each of these topics, as well as the particular role of electrospun fibres in addressing these challenges.
- Enhanced reconditioning of heavy-duty pulp industry equipment: Advantages of abrasive waterjet cuttingPublication . Ramalho, Armando Lopes; Silva, Agostinho da; Gaspar, Marcelo Calvete; Capela, Carlos; Celorrio-Barragué, Luis; Glăvan, Dan OvidiuWithin a pulp industry production process, a drop in the performance of a wood log rotary debarker was identified. Such loss of performance was due to the occurrence of excessive wear of the device's cutting blades, requiring their regular and premature replacement. The material used to manufacture the cutting blades, Hardox 500, has characteristics considered adequate for the required use. However, it was concluded that the blade manufacturing process degraded its mechanical properties, leading to its premature wear when placed in service. The present study intends to propose, characterize, and validate an alternative cutting process to manufacture the debarker's cutting blades. Abrasive waterjet cutting technology was proposed to produce the cutting blades. The suitability of this manufacturing process is discussed considering the specified geometry and the material characteristics of the resulting cutting blades.
- eServices - Service Platform for Pervasive Elderly CarePublication . Marcelino, Isabel; Laza, Rosalía; Domingues, Patrício; Gómez-Meire, Silvana; Pereira, AntónioIn this paper, we present a solution to improve elderly’s quality of life. eServices – Service platform for pervasive elderly care was designed to aggregate several services developed to meet senior population’s needs. It monitors basic life signs, environment variables and uses personal location technology. Besides sensor services, eServices solution contains digital services align with emotional and social care needs. Due to target population specifications, eServices was designed to be as simple and accessible as possible in order to remove technological barriers. One of eServices major features is to detect imminent danger situations, act accordingly. It also collects the data from the sensors, location routines and from the interactions between the elderlies and the provided services to detect behavior deviations in order to act preventively. The platform was tested by seniors in real scenario. The experimental results demonstrated that the proposed platform was well accepted and easy to use by seniors, which demonstrated enthusiasm and interest in daily bases use.
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