ESTG - Artigos em revistas internacionais
URI permanente para esta coleção:
Navegar
Entradas recentes
- Towards Improving Business Processes based on preconfigured KPI target values, Process Mining and Redesign PatternsPublication . Cherni, Jihen; Martinho, Ricardo; Ghannouchi, Sonia AyachiThe Business Process Management (BPM) lifecycle includes a redesign phase, which is an important step for stakeholders while working on the improvement of their Business Processes. Some research approaches on process improvement involve Key Performance Indicators and Process Mining, but essentially using the latter to verify if improvement efforts have been successful. In this paper, we propose a different approach for process improvement by first defining and configuring, process KPI target values, and second using Process Mining techniques to discover and analyze deviations from those values. Then, for each deviation we propose improvement solutions based on Business Process redesign patterns. Since this encompasses also an improvement cycle, we present our approach as an extension of the well-known BPM cycle. With this approach, process stakeholders will be able to quickly identify process KPI deviations based on quality, cost, time and flexibility, and resolve them by automatically applying proven redesign patterns.
- Challenges on the usability of digital platforms for informal caregivers and health professionals: the case study of Help2CarePublication . Ferreira Caroço, João Eduardo; Marques Gomes, Nuno Miguel; Martinho, Ricardo; Rijo, Rui; Peralta, Teresa; Carvalho, Daniel; Querido, Ana; Dixe, Maria dos AnjosThe usability of digital platforms assumes an important role in the support of health business processes. This is particularly relevant when these platforms automate previously manually-executed activities in a certain process, with the purpose of bringing time, cost and quality benefits both to end-users and health professionals. This is the main objective of the Help2Care e-Health digital platform, where informal caregivers can use a mobile app to access digital training materials on how to properly take care of their patients. Health professionals can, in turn, suggest these materials to their caregivers through a web application, communicate directly with them through a messaging system, and even perform remote health assessment and monitoring. However, the informal caregiver population presents specific attributes which, in general, require special attention for usability. Health professionals can also be challenged by such platforms and their inherent complexity. In this paper, we report the results and challenges of the usability studies performed on both mobile and web applications of the Help2Care platform.
- Digi&Mind: Development and validation of a multi-domain digital cognitive stimulation program for older adults with cognitive declinePublication . Couto, Filipa; Almeida, Maria de Lurdes; Dixe, Maria dos Anjos; Ribeiro, Jaime; Braúna, Mónica; Gomes, Nuno; Caroço, João; Monteiro, Luís; Martinho, Ricardo; Rijo, Rui; Apóstolo, João; Rijo, RuiOlder adults present a decline on their cognitive function. Digital cognitive interventions are related to the maintenance of cognitive function and are associated with better health-related outcomes. This study aims to describe the development process of a multi-domain digital cognitive stimulation program for older adults with cognitive decline. The digital program was developed in four phases: preliminary phase (conceptualization), modeling (experts panel), field test (usability tests), and consensus conference. To ensure software suitability the development process followed also software guidelines for mobile and web applications for older adults. The result was the Digi&Mind digital platform made of a mobile application a backoffice web application. The backoffice web application usability test was conducted with 7 healthcare professionals through the Post-Study System Usability Questionnaire System (PSSUQ). The mobile application test was conducted with 4 older adults and 7 professionals through direct observation user testing. Healthcare professionals considered that the system, the information and the interface had quality. Older adults considered the mobile application as appropriate, useful and easy to use, despite of their low digital experience.
- Performance Evaluation of OFDM Data Transmission Using a 2D Beamsteering TransmitarrayPublication . Reis, João R.; Ribeiro, Carlos; Duarte, Luis Diogo; Gomes, Rodolfo; Caldeirinha, Rafael F. S.This paper presents the analysis and characterisation of modulated data transmission, over-the-air, using an electronically Reconfigurable Transmitarray (eRT) composed of Frequency Selective Surfaces (FSS). The eRT, which has already been presented by the authors in previous work, is employed as a transmitter antenna on astate-of-the-art Orthogonal Frequency-Division Multiplexing (OFDM)-based Software Defined Radio (SDR), to enable electronically controlled two-dimensional beamsteering. A comparative study is presented by transmitting OFDM with and without the eRT attached at the transmitter’s horn antenna, in order to evaluate the impact that such man-made manufactured structures may have on real data transmission. The study is conducted at 5.2 GHz, when both transmitter and receiver antennas are aligned to each other but also when they are physically misaligned and the eRT is compensating for such angular mismatch. Error Vector Magnitude (EVM) and Bit-Error-Rate (BER) are used as figures of merit to evaluate the system’s performance. Results experimentally obtained inside an anechoic chamber show an enhancement on the system’s performance of 20 dB of gain on the average EVM, confirming the electromagnetic properties of the eRT.
- Fatigue behaviour of maraging steel samples produced by SLM under constant and variable amplitude loadingPublication . Branco, R.; Silva, J.; Ferreira, J. Martins; Costa, J.D.; Capela, C.; Berto, F.; Santos, L.; Antunes, F.V.This paper addresses the fatigue behaviour of AISI 18Ni300 samples manufactured by selective laser melting under both constant- and variable-amplitude loading. The fatigue campaign encompasses a series of low-cycle strain-controlled fatigue tests performed under fully-reversed conditions at various strain amplitudes, and a series of high-cycle stress-controlled fatigue tests performed under pulsating conditions at various stress ranges considering both constant- and variable-amplitude loading spectra. Fatigue life predictions are performed on the basis of the SWT parameter along with the Miner’s law. This approach has demonstrated to be sufficiently reliable to predict the lifetime expectancy in maraging steel samples produced by selective laser melting.
- Short-term load forecasting based on support vector regression and load profilingPublication . Sousa, João C.; Jorge, Humberto M.; Neves, Luís P.The article proposes a methodology to forecast the electric load for the 24 h of the following day based on support vector regression. The study considers 24 distinct models, one for each predicted hour, where each individual model is treated independently. Its objective is to find the optimal combination of support vector machine parameters that could generalize low forecasting errors, using simulated annealing as a metaheuristic. The adopted methodology is compared to concurrent methods based on neural networks when applied to a simulated load diagram (to illustrate a distribution feeder supplying a sample of 740 consumers). The results have proven its effectiveness with mean absolute percentage errors being less than 5% for testing samples. The study also focuses on evaluating the potential benefits of adopting load profiling information as input in support vector regression, giving a consistent proof of its importance.
- Influence of commensal bacteria on the proteolytic and antigenic profiles of INFOGEST-like digested wheat gliadinPublication . Pereira-Costa, Flávio; Domingues, Vanessa S.; Roque, Ana; Almeida, Zaida L.; Cruz, Pedro F.; Cordeiro, Rachel; Trindade, Daniela; Moura, Carla; Melo, Joana B.; Pereira, Sónia G.; Vaz, Daniela C.Introduction: Celiac disease (CeD) is a chronic autoimmune enteropathy developed by genetically predisposed individuals when exposed to gluten. Gluten gliadins, along with gut microbiota, may influence CeD onset and progression through mechanisms that remain unclear. Methods: Gliadin-degrading bacterial isolates obtained from CeD patients, and their 1st-degree relatives’ stool and blood were identified (Bacillus tropicus, Enterococcus faecalis, Micrococcus sp., Cronobacter sakazakii, Pseudomonas aeruginosa, and Serratia marcescens) and used in an INFOGEST-like protocol to simulate gliadin digestion after 4 h (digested gliadin, d-gliadin). The d-gliadin digesta were analyzed by fast protein liquid chromatography (FPLC), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), fluorescence spectroscopy, and polyclonal and monoclonal (R5 and G12) enzyme-linked immunosorbent assays (ELISA). Results and discussion: In the absence of the bacterial isolates, gliadin is poorly digested and self-assembles within 1 day into intermediate and large protein oligomers/aggregates, enriched in β-sheet structure (FTIR amide I band between 1,600 and 1,700 cm−1) and able to bind thioflavin T and Congo red. Conversely, in the presence of the bacterial isolates, gliadin is further digested, leading to an increase in protein fragments. After 4 h, the P. aeruginosa, C. sakazakii, and B. tropicus d-gliadin digesta presented a mixture of d-gliadin peptides and aggregates that showed higher antigenicity (associated with the exposure of the 5-amino acid QQPFP and 6-amino acid QPQLPY epitopes, present in the 25-mer and 33-mer, respectively) than control digestions (without bacteria), while E. faecalis led to lower antigenicity. In turn, within 24 h of incubation, all bacterial isolates led to the formation of undigested material with lower antigenicity, either due to fewer 33-mers and 25-mers in solution, or to fragment aggregation into amorphous material, not exposing antigenic sequences. Hence, intestinal flora may enhance or diminish the antigenicity of gliadin, thereby modulating the immunogenic response to gliadin/gluten.
- Estimation of pedestrian walking speeds on footwaysPublication . Silva, Ana Maria César Bastos; Cunha, Joana Rita Rasteiro da; Silva, João Pedro Cruz daPedestrian circulation is increasingly considered as an alternative and environmentally sustainable mode of transport, thus justifying the need for safe and efficient pedestrian infrastructure. One of the essential parameters for the design of this walking infrastructure is the walking speed adopted by pedestrians in different situations. In this context, the present research focused on the identification and evaluation of the effects that several factors have on pedestrian walking speed. Furthermore, a mathematical model estimating pedestrian walking speed according to the relevant variables was also developed, based on multiple linear regression techniques. In general, the conclusions of these analyses confirm the results found in the specialised literature, pointing to an average pedestrian walking speed of 1·25 m/s, with a minimum of 0·68 m/s and a maximum of 1·92 m/s. The final results confirmed the need for the development of technical guidelines that are appropriate for the design of footways in urban environments.
- Fabrication and characterisation of PCL and PCL/PLA scaffolds for tissue engineeringPublication . Patrício, T.; Domingos, M.; Gloria, A.; D'Amora, U.; Coelho, J. F.; Bartolo, P.J.Purpose – The main purpose of this research work is to study the effect of poly lactic acid (PLA) addition into poly (e-caprolactone) (PCL) matrices, as well the influence of the mixing process on the morphological, thermal, chemical, mechanical and biological performance of the 3D constructs produced with a novel biomanufacturing device (BioCell Printing). Design/methodology/approach – Two mixing processes are used to prepare PCL/PLA blends, namely melt blending and solvent casting. PCL and PCL/PLA scaffolds are produced via BioCell Printing using a 300-mm nozzle, 0/908 lay down pattern and 350-mm pore size. Several techniques such as scanning electron microscopy (SEM), simultaneous thermal analyzer (STA), nuclear magnetic resonance (NMR), static compression analysis and Alamar BlueTM are used to evaluate scaffold’s morphological, thermal, chemical, mechanical and biological properties. Findings – Results show that the addition of PLA to PCL scaffolds strongly improves the biomechanical performance of the constructs. Additionally, polymer blends obtained by solvent casting present better mechanical and biological properties, compared to blends prepared by melt blending. Originality/value – This paper undertakes a detailed study on the effect of the mixing process on the biomechanical properties of PCL/PLA scaffolds. Results will enable to prepare customized PCL/PLA scaffolds for tissue engineering applications with improved biological and mechanical properties, compared to PCL scaffolds alone. Additionally, the accuracy and reproducibility of by the BioCell Printing enables to modulate the micro/macro architecture of the scaffolds enhancing tissue regeneration.
- Automatic concrete health monitoring: assessment and monitoring of concrete surfacesPublication . Valença, Jónatas; Dias-da-Costa, Daniel; Gonçalves, Luísa; Júlio, Eduardo; Araújo, HelderTo predict the degradation of concrete structures is extremely challenging. The typical approach combines periodic visual inspections with required non-destructive tests. However, this methodology only discretely evaluates few areas of the structure, being also time consuming and subject to human error. Therefore, a new method designated ‘automatic concrete health monitoring’ is herein presented which aims at automatically characterising and monitoring the state of conservation of concrete surfaces by combining photogrammetry, image processing and multi-spectral analysis. The method was designed to (i) characterise crack pattern, displacement and strain fields; (ii) map damages and (iii) assess and define restoration tasks.