Browsing by Issue Date, starting with "2019-09"
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- Introdução à Ciência Política - Colectânea de actividades interactivas na aulaPublication . Silveira, PedroColectânea de actividades interactivas na aula
- Enhancing Civil Engineering teaching through 3D Computer Aided DesignPublication . Gonçalves, Jorge H.G.; Santos, Bertha3D interpretation of 2D drawing is not easy for most of the Civil Engineering first-year students. Some do it naturally but most need to be trained to master this skill. In this paper, the implemented teaching methodologies aiming to facilitate the acquisition of three-dimensional project visualization skills are presented. These methodologies were developed during the last two years targeting first-year Civil Engineering students at the University of Beira Interior (Portugal). After a first contact with 2D project representation through manual drawing, students progressively elaborate computer-aided design (CAD) project starting with simple 2D drawings and culminating with a 3D project of a pre-existing building. Students are also motivated to improve their 3D graphic representation skills through a classroom contest where the winning project is printed in 3D. The training in 2D and 3D graphic representation is complemented during the second year with several in situ surveys and computer-aided drawing of topographic data. This approach proved to be very interesting for competence acquisition, qualifying students for a better 3D representation and interpretation. Students also found this methodology to be motivating.
- Data Collection Methodology to Assess Road Pavement Condition Using GNSS, Video Image and GISPublication . Santos, Bertha; Almeida, Pedro Gabriel De; Maganinho, Leonor Graciete de OliveiraTraffic loads, along with the environment, damage pavement over time. The degradation of pavement quality is reflected in the development of a diversity of pavement distresses, such as cracking, deformation or deterioration. These distresses may occur on the surface and/or in the pavement structure, having a determinant role in pavement’s quality. Aiming to increase the degree of reliability of the pavement distress data and reduce pavement observation time and visual inspection operations cost, this work presents the main steps proposed for a methodology to observe, record and evaluate flexible road pavement distresses to assess the quality of road pavements. This methodology is based on an in-vehicle inspection using GNSS and video image capture devices and in the use of Geographic Information System (GIS). Validation of the proposed methodology was made through a case study by comparing the results obtained on the in-vehicle inspection to those from a traditional visual inspection performed on foot. The similarity of results obtained by the two approaches allowed to conclude about the feasibility of the proposed methodology. Among the main advantages of the proposed methodology a highlight is on the possibility to identify, quantify and locate the most severe pavement distresses through the use of spatial tools available on GIS, producing information maps and reports that can be used in the decision-making process about road pavements rehabilitation and conservation.
- Optimal location and setting of time modulated PRVs for water loss reduction with leakage modelling by pressure driven analysisPublication . Sousa, J.; Muranho, João; Sá Marques, Alfeu; Gomes, RicardoWater losses have economical, technical, social and environmental negative impacts and so water companies are always willing to reduce them. The IWA Water Loss Task Force identified four main control strategies to reduce real losses: 1) infrastructure management; 2) pressure management; 3) active leakage control; and 4) speed and quality of repairs. Unreported leaks and background leakage usually represent a major component of water losses and pressure management is an effective, easy, economic and quick solution to reduce it. Pressure management can be implemented by introducing Pressure Reduction Valves (PRVs): fixed-outlet; time-modulated; flow-modulated and pressure modulated. For a fixed-outlet PRV there is a single working condition (pressure downstream of the PRV is always the same). For a time-modulated PRV there can be several working conditions (for instance, a lower pressure during the night period - from 0 to 6 am, and higher one during the remainder of the day). The flow-modulated and pressure modulated PRVs are more efficient because they constantly try to adjust the working conditions to reach the minimum pressure required at the critical node. However, pressure management projects must be preceded by specialized studies (identify the optimal location and settings of the PRVs to install) and cost benefit analysis (assessment of economic viability). A previous work presented a methodology to help in those tasks, by identifying the optimal location and setting of fixed-outlet PRVs to reduce water losses in WDNs and maximize the NPV of pressure management projects. Now the methodology was extended to include also time modulated PRVs and this paper presents the results obtained for a hypothetical case study.
- Blockchain-based Decentralized Application for Electronic Voting Using an Electronic IDPublication . Monteiro, José Diogo Soares Albergaria Serejo; Sequeiros, João B. F.; Freire, Mario; Inácio, Pedro R. M.In this work, we present a decentralized and self-tallying electronic voting protocol that substantially enhances the privacy of voters and diminishes centralization. ese properties are accomplished through a symbiotic relationship between the Ethereum Blockchain and the Portuguese electronic ID. Unlike previously proposed Blockchain e-voting protocols, this is the rst implementation that more closely ful lls most of the security requirements of a real-world voting scheme. Furthermore, our system improves currently in-use e-Voting systems by using a self-tallying protocol. us, each voting citizen is able to compute the election tally and has complete control over their own vote. e execution of this protocol is enforced using the consensus mechanism that safeguards the Ethereum Blockchain. To prove its feasibility, we tested the implementation on the o cial PoW (Proof of Work) test network of Ethereum (Ropsten). e - nancial and computational breakdowns are on par with the leading Blockchain e-voting protocol.
- Pedestrian Road Accident Index for Municipalities: The Portuguese CasePublication . Santos, Bertha; Carvalheira, CarmenPortuguese road traffic accidents statistics show that the number of accidents with fatalities and serious injuries has in general decreased in recent years. However, the number of accidents involving pedestrians is still high when compared with those observed in other countries of the European Union. In order to assess this problem, an index of pedestrian road traffic accidents for municipalities that could be used in decision-making about pedestrian safety measures is proposed. The use of absolute values of accidents involving pedestrians (running over) does not allow itself a reliable comparison of pedestrian safety level between municipalities. In this sense, the approach proposed uses the information available in the Portuguese database PORDATA to calculate a municipal index that takes into account the degree of exposure of pedestrians to accident, based on national and municipal resident population annual growth rates and number of pedestrian's casualties. This index allows to identify the municipalities with unfavourable deviation to national numbers of road accidents involving pedestrians (per 10000 inhabitants), supporting the plan and allocation of human and economic resources for the diagnosis, definition and implementation of safety measures. The results obtained can be visualized in a GIS for a more comprehensive comparison between municipalities. The analyses performed for Portugal showed that, in general, municipalities with higher resident population annual growth rates, located mostly along the coastline and in more consolidated urban areas, tend to present better index values, which points to the need to intervene in less consolidated areas.
- Association and Temporality between News and TweetsPublication . Cordeiro, João; Brazdil, Pavel; Moutinho, VâniaWith the advent of social media, the boundaries of mainstream journalism and social networks are becoming blurred. User-generated content is increasing, and hence, journalists dedicate considerable time searching platforms such as Facebook and Twitter to announce, spread, and monitor news and crowd check information. Many studies have looked at social networks as news sources, but the relationship and interconnections between this type of platform and news media have not been thoroughly investigated. In this work, we have studied a series of news articles and examined a set of related comments on a social network during a period of six months. Specifically, a sample of articles from generalist Portuguese news sources published in the first semester of 2016 was clustered, and the resulting clusters were then associated with tweets of Portuguese users with the recourse to a similarity measure. Focusing on a subset of clusters, we have performed a temporal analysis by examining the evolution of the two types of documents (articles and tweets) and the timing of when they appeared. It appears that for some stories, namely Brexit and the European Football Cup, the publishing of news articles intensifies on key dates (event-oriented), while the discussion on social media is more balanced throughout the months leading up to those events.
- Calibration in Water Distribution Networks with Pressure-Driven AnalysisPublication . Muranho, João; Ferreira, Ana; Gomes, Abel; Sousa, J.; Marques, Alfeu SáWater distribution networks (WDN) connect consumers to the water sources, and its goal is to fulfil water demand. However, it is a well-known fact that WDN have losses and an important part of them occur at pipe level. Despite all the research efforts focused on this subject, the identification of leaky pipes is still a major challenge. EPANET is frequently used to simulate WDN’ models, using a link-node formulation, similar to a graph, where the water demands are assigned to the nodes. A linearized system of equations (mass and energy conservation laws) is iteratively solved by a Newton-Raphson algorithm. The EPANET is demand-driven, since it assumes the water pressure is always enough to satisfy the demands. However, on real WDN, states of insufficient pressure also occur. Besides that, the demand-driven approach is not suitable for pipe leakage simulation, which depends on the pressure. WaterNetGen — an EPANET extension— allows both demand and pressure driven simulations, including pipes’ leakage modelling. However, the leakage parameters (bursts and background leakage coefficients and exponents) must be set manually by an expert — manual calibration — for the whole network or for each pipe. This work proposes a calibration methodology to estimate the pipe background leakage parameters. The approach is tested on a set of synthetic models, generated by WaterNetGen, and then applied to a real WDN to assess its performance on real world conditions.
- Spline parameterization based nonlinear trajectory optimization along 4D waypointsPublication . Ahmed, Kawser; Bousson, K.; Coelho, MilcaFlight trajectory optimization has become an important factor not only to reduce the operational costs (e.g.,, fuel and time related costs) of the airliners but also to reduce the environmental impact (e.g.,, emissions, contrails and noise etc.) caused by the airliners. So far, these factors have been dealt with in the context of 2D and 3D trajectory optimization, which are no longer efficient. Presently, the 4D trajectory optimization is required in order to cope with the current air traffic management (ATM). This study deals with a cubic spline approximation method for solving 4D trajectory optimization problem (TOP). The state vector, its time derivative and control vector are parameterized using cubic spline interpolation (CSI). Consequently, the objective function and constraints are expressed as functions of the value of state and control at the temporal nodes, this representation transforms the TOP into nonlinear programming problem (NLP). The proposed method is successfully applied to the generation of a minimum length optimal trajectories along 4D waypoints, where the method generated smooth 4D optimal trajectories with very accurate results.
- Validation of NoSAS (Neck, Obesity, Snoring, Age, Sex) score as a screening tool for obstructive sleep apnea: Analysis in a sleep clinicPublication . Coutinho Costa, J.; Rebelo-Marques, A.; Machado, João Neiva; Gama, Jorge; Santos, C.; Teixeira, F.; Moita, J.Screening methods have become increasingly important due to the growing number of patients suspected of having obstructive sleep apnea (OSA) being referred to sleep clinics. The Lausanne NoSAS (Neck circumference, Obesity, Snoring, Age, Sex) score test is a simple, efficient, and easily employed tool enabling identification of individuals at risk for the disease. The score ranges from 0 to 17 and the patient has a high probability of OSA if they have a NoSAS score of 8 or higher.