ESTG - Comunicações em conferências e congressos internacionais
Permanent URI for this collection
Browse
Recent Submissions
- In Case of Doubt See the Manual: A Comparative Analysis of (Self)Learning Packages Qualitative Research SoftwarePublication . Freitas, Fábio; Ribeiro, Jaime; Brandão, Catarina; Souza, Francislê Neri de; Costa, António Pedro; Reis, Luís PauloOne of the first precautions that a consumer/user has when acquiring a new product is related to how to use it. In this context, the user manuals can be assumed as one of the main communication channels between the companies that develop the products and the user. Regarding the use of software packages, literature indicates that one of the decisive factors for user’s dissatisfaction is related to the difficulty in learning how to work with a software. In this context, Qualitative Data Analysis Software (QDAS) enterprises are increasingly looking to develop features that can decrease user’s learning curve of their tools. In this way, this chapter illustrates a comparison of user support features, such as: support and typology of the User Manual; Training; Tutorials; Forums; Frequently asked questions (FAQ’s); Workshops. Through a systematic exploration of the native sites guided by a dedicated checklist, it was sought to identify the singularities of the resources to support (self)learning of the different software packages. In order to systematize the offers that each user can find, enabling him/her to choose the package that provides the solutions that best respond to his/her learning style. It was concluded that among the different software packages there are no noteworthy disparities, only in two packages analysed there were shortcomings in the offer of formative and autonomous learning.
- Pervasive Business Intelligence: A Key Success Factor for BusinessPublication . Guarda, Teresa; León, Marcelo; Augusto, Maria Fernanda; Mota Pinto, Filipe; Barrionuevo, Oscar; Villao, DatzaniaToday the strategic significance of information is fundamental to any organization. With the intensification of competition between companies in open markets and often saturated, companies must learn to know themselves and to the market through the collection and analysis of quality information. The strategic information is seen as a key resource for success in the business, which is provided by Business Intelligence systems. A successful business strategy requires an awareness of the surrounding (internal and external) environment of organizations, including customers, competitors, industry structure and competitive forces. Managing the future means not only is able to anticipate what will happen outside the organization, but also be able to represent the events through their own actions timely. To make it possible, Pervasive Business Intelligence arises as a natural evolution of business intelligence applications in organizations, allowing to companies achieve and maintain a sustainable competitive advantage, helping managers react proactively in a timely manner to threats and opportunities.
- Accessibility in Software Engineering: Pursuing the Mainstream from a ClassroomPublication . Silva, João; Gonçalves, Ramiro; Martins, José; Branco, Frederico; Pereira, AntónioThough equal access to all digital devices, content and applications should be ensured by default in the Digital Age, reality has yet to match this ideal, despite the numerous efforts to raise awareness of the problem. For the visually impaired, the existence of e-accessibility issues represents a barrier that, in the majority of situations, cannot be overcome. Nevertheless, this group of individuals still insists on using digital devices, to carry out tasks from their daily lives, such as reading and writing e-mails, reading news and weather websites, and using social networks. This assumption has been validated through a survey completed by 29 blind or partially sighted individuals. Considering that the lack of depth of knowledge in developers constitutes one of the most significant constraints to the development of accessibility software and digital content, the proposal for “slide 0” to be included as an educational resource, when developers are learning how to engineer software, is discussed later in the paper. This contribution, if precisely focused on the various types of software projects, would represent a novel addition to the existing scientific literature, but also a comprehensive aid to the inclusion of e-accessibility when lecturing experts on software engineering.
- Alternative heavy tailed models in seismologyPublication . Felgueiras, Miguel; Martins, João; Santos, RuiGreat earthquakes are commonly considered as the ones with moment magnitude (Mw ) above or equal to 8.0. Since these earthquakes can destroy entire communities located near the epicentre, the search of physical laws that explain the energy released by them is an important issue. There is a connection between the radiated energy of an earthquake, its magnitude and its seismic moment (M 0). Thence, when fitting a heavy or an extremely heavy tailed distribution to a seismic moment dataset, we are in fact adjusting a mathematical model which explains the amount of energy released by these great seisms. Therefore, the main goal of this work is to study the more appropriated Pareto based models (the most used family in this field) when explaining the seismic moment of the great earthquakes. With this purpose in mind, we selected two different catalogs that accommodate recent events and are considered more accurate than other catalogs used in previous works. We conclude that the traditional Pareto distribution remains a good choice to deal with this kind of data, but Log-Pareto lead to higher p-values and Location-scale Pareto is better fitted to the biggest events.
- All-digital reconfigurable STDCC radar baseband implementation in FPGAPublication . Duarte, Luís; Ribeiro, Carlos; Alves, Luís N.; Caldeirinha, Rafael F. S.This paper reports the architecture of an all-digital Swept Time-Delay Cross-Correlator (STDCC) baseband. Until recently, the sliding correlator technique has been mainly em-ployed for sounding the radio propagation channel. However, recent benchmarks have shown promising results in target detection context when compared to commercially available solutions. STDCC takes advantage of the sliding correlation properties of Pseudo-Noise (PN) sequences. Therefore, this paper presents the baseband generation for this new radar technique with on-the-fly sequence tuning using a Field-Programmable Gate Array (FPGA). The reconfigurable STDCC radar baseband generates both PN sequences digitally and requires a low-cost ADC to acquire the time dilated result. At the end, the proposed architecture is evaluated regarding resource usage efficiency and then the radar performance will be discussed in terms of the all-digital PN sequence spectrum and the real-time slide correlation. Our analysis confirmed a strong correlation between both sequence length and sampling frequency with radar detectable distance.
- Light field image coding: objective performance assessment of Lenslet and 4D LF data representationsPublication . Monteiro, Ricardo; M. M. Rodrigues, Nuno; Faria, Sergio; Nunes, paulo; Tescher, Andrew G.State-of-the-art light field (LF) image coding solutions, usually, rely in one of two LF data representation formats: Lenslet or 4D LF. While the Lenslet data representation is a more compact version of the LF, it requires additional camera metadata and processing steps prior to image rendering. On the contrary, 4D LF data, consisting of a stack of sub-aperture images, provides a more redundant representation requiring, however, minimal side information, thus facilitating image rendering. Recently, JPEG Pleno guidelines on objective evaluation of LF image coding defined a processing chain that allows to compare different 4D LF data codecs, aiming to facilitate codec assessment and benchmark. Thus, any codec that does not rely on the 4D LF representation needs to undergo additional processing steps to generate an output comparable to a reference 4D LF image. These additional processing steps may have impact on the quality of the reconstructed LF image, especially if color subsampling format and bit depth conversions have been performed. Consequently, the influence of these conversions needs to be carefully assessed as it may have a significant impact on a comparison between different LF codecs. Very few in-depth comparisons on the effects of using existing LF representation have been reported. Therefore, using the guidelines from JPEG Pleno, this paper presents an exhaustive comparative analysis of these two LF data representation formats in terms of LF image coding efficiency, considering different color subsampling formats and bit depths. These comparisons are performed by testing different processing chains to encode and decode the LF images. Experimental results have shown that, in terms of coding efficiency for different color subsampling formats, the Lenslet LF data representation is more efficient when using YUV 4:4:4 with 10 bit/sample, while the 4D LF data representation is more efficient when using YUV 4:2:0 with 8 bit/sample. The “best” LF data representation, in terms of coding efficiency, depends on several factors which are extensively analyzed in this paper, such as the objective metric that is used for comparison (e.g., average PSNR-Y or average PNSR-YUV), the type of LF content, as well as the color format. The maximum objective quality is also determined, by evaluating the influence of each block from each processing chain in the objective quality of the reconstructed LF image. Experimental results show that, when the 4D LF data representation is not used the maximum achieved objective quality is lower than 50 dB, in terms of average PSNR-YUV.
- Energy consumption behaviour characterization with mobile gamificationPublication . Toasa, Renato; Silva, Carlos; Silva, Catarina; Gonçalves, Dulce; Neves, Luis; Marcelino, LuisExcessive electric energy consumption results in high costs for consumers, and often on using non-renewable resources. Additionally, in many cases, it is difficult for the consumer or for the energy provider to determine if one or more equipment is being used efficiently. Therefore, the main objective of this work is to promote awareness about energy consumption. For that purpose, a mobile application with a gamification approach was designed to identify users’ behaviors towards the use of energy and, based on the user’s answers, offer advices to save energy and promote ecological awareness. The outcome of using gamification on a mobile application with such goals results in a streamlined data collection application that combines information and entertainment. The collected information is being gathered to potentially create consumer profiles that better reflect the user’s energy consumption.
- Deep Learning-based Point Cloud Geometry Coding with Resolution ScalabilityPublication . Guarda, André F. R.; Rodrigues, Nuno M. M.; Pereira, FernandoPoint clouds are a 3D visual representation format that has recently become fundamentally important for immersive and interactive multimedia applications. Considering the high number of points of practically relevant point clouds, and their increasing market demand, efficient point cloud coding has become a vital research topic. In addition, scalability is an important feature for point cloud coding, especially for real-time applications, where the fast and rate efficient access to a decoded point cloud is important; however, this issue is still rather unexplored in the literature. In this context, this paper proposes a novel deep learning-based point cloud geometry coding solution with resolution scalability via interlaced sub-sampling. As additional layers are decoded, the number of points in the reconstructed point cloud increases as well as the overall quality. Experimental results show that the proposed scalable point cloud geometry coding solution outperforms the recent MPEG Geometry-based Point Cloud Compression standard which is much less scalable.
- Hardware-in-the-loop system numerical methods evaluation based on brush DC-motor modelPublication . Mudrov, Mikhail; Zyuzev, Anatoliy; Konstantin, Nesterov; Valtchev, Stanimir; Valtchev, SvilenHardware-in-the-loop (HiL) systems nowadays become popular. During the HiL creation process it is important to select a proper numerical method because the accuracy of the process simulation, in case of the HiL, depends on the correct numerical approach selection. That is why it is important to evaluate the most popular numerical approaches. The “Sequential” Euler (solves equations step-by-step), the Forward Euler (the most popular method for HiL creators), and the Second-order Adams-Bashforth approach are under consideration. A mathematical model based on the DC-motor with independent excitation is selected as a basis for the experimental numerical calculation. In consequence, recommendations for the numerical method selection are given, based on the obtained results.
- Compression of medical images using MRP with bi-directional prediction and histogram packingPublication . Santos, Joao M.; Guarda, Andre F.R.; Cruz, Luís A. da Silva; Rodrigues, Nuno M. M.; Faria, Sergio M. M. deMedical imaging technology has become essential for the improvement of medical practice. This led to advances in the technology, namely in image sampling resolutions, pixel bit-depth and inter slice resolution. Additionally, common use of medical images, the life expectancy of patients and legal restrictions led to increasing storage costs. Therefore, efficient compression of medical image data is in high demand, for archiving and transmission. In this work we propose to improve the compression efficiency of the Minimum Rate Predictors lossless encoder, by adding bi-directional prediction support and a histogram packing technique. The results show that the proposed method presents a higher compression efficiency than state-of-the-art HEVC encoder. The compression efficiency is improved by 20%, on average, when compared to HEVC and by 46.1% when compared with the original MRP algorithm.