21 research outputs found
Correction to: [18F]mFBG PET‑CT for detection and localisation of neuroblastoma: a prospective pilot study (European Journal of Nuclear Medicine and Molecular Imaging, (2023), 50, 4, (1146-1157), 10.1007/s00259-022-06063-6)
No full textThe article [ 18F]mFBG PET‑CT for detection and localisation of neuroblastoma: a prospective pilot study, written by Atia Samim, Thomas Blom, Alex J. Poot, Albert D. Windhorst, Marta Fiocco, Nelleke Tolboom, Arthur J. A. T. Braat, Sebastiaan L. Meyer Viol, Rob van Rooij, Max M. van Noesel, Marnix G. E. H. Lam, Godelieve A. M. Tytgat, and Bart de Keizer, was originally published Online First without Open Access. After publication in volume 50, issue 4, page 1146 - 1157 the author decided to opt for Open Choice and to make the article an Open Access publication
Engineering Critical Assessment for girth welds in reeled pipeline: Development of a probabilistic methodology
No full textPipe laying projects are getting more challenging due to increasing operational depth of pipeline. The increasing depth requires more of the strength and load bearing capability of the pipeline and its girth welds. The assessment method used for checking the integrity of flaws in girth welds is called Engineering Critical Assessment (ECA) and is based on fracture mechanics (FM) formulas. A complete ECA covers both static and fatigue loading encountered over the multiple phases of the pipe laying process. The current ECA methodology for both static and fatigue load produces strict requirements that may cause unnecessary repairs of the girth welds. From within the industry it is now wondered if ECA produces (over) conservative results.The current static ECA methodology uses a worst case (deterministic) load scenario as input to determine the maximum allowable initial flaw depth (MAIF) of a girth weld which is then directly used as NDT criterion for that specific pipeline project. The proposed methodology in this research uses a reliability based approach where the probability of failure (PoF) of the pipeline/girth welds is governing in order to determine the NDT criteria. By (conservatively) assuming girth welds in a pipeline form an independent series system, the required PoF of the pipeline () can be converted to the individual required PoF of a girth weld (). This together with stochastic input variables provides the required information to determine the NDT criterion based on the required PoF of the pipeline.The available data to determine the best probability density functions (PDFs) of the stochastic variables used in the reliability based approach is limited, introducing uncertainty in the accuracy of the results. However when using the limited data the two models already provide NDT criteria in the range of 5.05mm-5.20mm, while the deterministic approach dictates a NDT criteria of 4.45mm. A difference of 0.55mm-0.75mm is substantial in terms flaw assessment criteria. Experts on welding and flaw assessment within HMC estimate the impact of the increase in NDT criterion to result in one less offshore shift of 12 hours, potentially saving up to hundred of thousands of Euros.From the research performed it may be concluded it is possible to provide NDT criteria on basis of a probabilistic ECA, it is found the current ECA for static loading on external weld flaws might indeed be conservative. Therefore using a probabilistic approach towards ECA for both static and fatigue loading can benefit future projects by reducing repairs and cost.<br/
Impregnation quality of shredded semipreg after compression moulding
Full text linkManufacturing of thermoplastic composites (TPC) inherently generates scrap, mainly in the form of offcuts or rejected parts. The growth of TPC over recent decades has now reached a point where developing specific recycling solutions for TPC waste has become crucial. While looking at the various steps during which scrap is produced, the nesting of semipreg or prepreg appears to be critical. This work aims to develop a route for recycling semipreg offcuts, comprising shredding and compression moulding. This article focuses on an experimental study of the compression moulding step of carbon fibres reinforced PPS (C/PPS) to investigate the uniformity and impregnation quality of plates. These plates were realised in a picture frame while varying both the fibre volume content between 30% and 50% and the processing parameters. Visual inspection and cross-sectional microscopy were performed to assess the quality of each plate. As a first step, the influence of the type of added matrix (film, powder, pellets) and the type of pre-impregnation (film, powder) was studied. Stacking of polymer powder with shredded powder-coated semipreg gave the best impregnation quality. It was also shown that longer dwell time at melt leads to better consolidation quality. However, the difficulty in obtaining good impregnation comes from the disentangled shredded material, which is composed of three forms: semipreg flakes, dry bundles and pieces of matrix. When dry bundles reach the mould surfaces during the filling of the mould or when they are packed together, the consolidation cycle hardly impregnates them and they remain dry afterwards. Furthermore, large local variations of fibre fraction were noticed, resulting from a random mould filling. Therefore, the recycling solution for shredded semipreg is feasible when the fibre fraction is reduced but improvements on the part variability still have to be made
Design of a Cutting Edge Low-Emission Low-Noise Aircraft
No full textThe final report focused on the detailed design of the final chosen concept, which is a BWB aircraft with a distributed propulsion system powered by liquid hydrogen. Before doing the actual technical design part, a market analysis is made to investigate the future demand for this type of aircraft. To do so, the SWOT analysis, market characteristics, and competitor analysis are made. After that, an estimation of the market dynamics & trends, as well as the expected demand for the aircraft is made. In financial analysis, the financial forecast and strategies for the whole aircraft program are discussed, from which the unit cost, operational cost, return on investment and cost-breakdown structure can be found. The report concludes that the Lightning2 program is a promising step towards more sustainable aviation. It emphasizes the need for further development and adaptation to technological advancements to maintain a competitive position in the marketAE3200 - Design Synthesis ExerciseAerospace Engineerin
“GETTING REAL” WITH ACTION RESEARCH IN TECHNOLOGY-MEDIATED TASK-BASED LANGUAGE TEACHING (TBLT): A PROPOSITION, A MAP AND THREE CASE STUDIES
No full textSince the turn of the century, the field of (first and second) language teaching has witnessed the steady rise to prominence of “task-based language teaching” (TBLT) as a pedagogic framework for the acquisition of linguistic competencies. TBLT is a Dewey-inspired experiential learning approach, in which learners engage in a meaningful, primarily non-linguistic activity – a task – “in order to attain an objective, and which necessitates the use of language” (Van den Branden 2006, p. 4). In recent years, TBLT has attracted increasing attention from educators exploring the use of technology to enhance the learning process. According to González-Lloret, for instance, “TBLT presents an ideal platform for informing and fully realizing the potential of technological innovations for language learning” (2017, p. 193). Technology-mediated or technology-enhanced TBLT creates a surplus learning outcome, as not only linguistic/communicative but also technological/digital competencies are necessary to attain the task objective (Gonzalez-Lloret 2014).
There is a danger, however, that the TBLT approach is reduced to “a point where almost anything related to educational activity can (…) be called a ‘task’” (Van den Branden 2006, p. 3). In response, practitioners of technology-mediated TBLT (e.g. González-Lloret 2014; Lopes 2017) defined several criteria for tasks, such as authenticity, motivation, meaning, purpose, process/outcome and social interaction - all of which, at their core, presuppose “a ‘real-world relationship’” (González-Lloret 2014, p. 6). Strikingly, this insistence on authenticity and real-world experience can be perceived to exist at odds with the interest that many researchers of technology-mediated TBLT entertain for synthetic immersive environments (SIEs) such as online multiplayer games, digital augmented reality games and virtual environments (deFreitas 2006; Sykes 2014; Gánem-Gutiérrez 2014).
The central proposition of this paper is that the methodological framework of Action Research (AR) provides a pathway towards integrating technology into TBLT while guaranteeing an indubitably authentic, real-world task design. AR, after all, “takes place in real-world situations, and aims to solve real problems” (McIntyre et al. 2015, p. 193), unlike the “quests” performed in SIEs. I argue that AR provides as much of “an ideal platform for (…) fully realizing the potential of technological innovation” as TBLT does, as all of the stages of AR, from gathering and processing data to reporting results and taking informed action, benefit greatly from the introduction of technological tools. I also argue that AR not only integrates linguistic and digital learning outcomes, like technology-mediated TBLT, but also develops learners’ research competencies.
To support the argument, this paper provides a mapping of useful technological tools onto a structured overview of the stages in AR. Moreover, the paper discusses empirical evidence provided by three case studies in which technological tools enable an AR project with a strong real-world relationship and with valuable learning outcomes in the fields of language acquisition, digital literacy and research skills. I performed these case studies at:
a) the Faculty of Industrial Engineering Sciences (KU Leuven & UHasselt, Campus Diepenbeek),
b) the Department of Teacher Training (UC Leuven Limburg)
c) the Department of Applied Psychology (UC Thomas More Antwerp).
Keywords: Task-Based Language Teaching, Technology in Education, Action Research, Action Learning, Digital Literacy, Research Skills, Language Acquisition.sponsorship: The author wishes to extend his gratitude to all the project members involved in the two OOF-projects mentioned above: Carolien Frijns, Tom Van Daele, Bart Geerts, Michiel Kragten, Martine Peetermans, Marnik Lenaerts, Bas Bergervoet, Stijn Van Laer, Sebastiaan Jans, Lieve Luyten, Miet Craeynest, Karine Nicolay, Guido Cajot, Dinska Van Gucht, Leen Bastiaansen, Dagmar Versmissen, Etienne Van Hoof and Myriam Meyers -and also to the OnderwijsOntwikkelingsFonds (OOF) of KU Leuven for its financial support. (KU Leuven)status: Publishe
HeadPrint: Detecting anomalous communications through header-based application fingerprinting
Full text linkPassive application fingerprinting is a technique to detect anomalous outgoing connections. By monitoring the network traffic, a security monitor passively learns the network characteristics of the applications installed on each machine, and uses them to detect the presence of new applications (e.g., malware infection). In this work, we propose HeadPrint, a novel passive fingerprinting approach that relies only on two orthogonal network header characteristics to distinguish applications, namely the order of the headers and their associated values. Our approach automatically identifies the set of characterizing headers, without relying on a predetermined set of header features. We implement HeadPrint, evaluate it in a real-world environment and we compare it with the state-of-the-art solution for passive application fingerprinting. We demonstrate our approach to be, on average, 20% more accurate and 30% more resilient to application updates than the state-of-the-art. Finally, we evaluate our approach in the setting of anomaly detection, and we show that HeadPrint is capable of detecting the presence of malicious communication, while generating significantly fewer false alarms than existing solutions.Cyber Securit
Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19 disease.
Full text linkBACKGROUND
Some people with SARS-CoV-2 infection remain asymptomatic, whilst in others the infection can cause mild to moderate COVID-19 disease and COVID-19 pneumonia, leading some patients to require intensive care support and, in some cases, to death, especially in older adults. Symptoms such as fever or cough, and signs such as oxygen saturation or lung auscultation findings, are the first and most readily available diagnostic information. Such information could be used to either rule out COVID-19 disease, or select patients for further diagnostic testing.
OBJECTIVES
To assess the diagnostic accuracy of signs and symptoms to determine if a person presenting in primary care or to hospital outpatient settings, such as the emergency department or dedicated COVID-19 clinics, has COVID-19 disease or COVID-19 pneumonia.
SEARCH METHODS
On 27 April 2020, we undertook electronic searches in the Cochrane COVID-19 Study Register and the University of Bern living search database, which is updated daily with published articles from PubMed and Embase and with preprints from medRxiv and bioRxiv. In addition, we checked repositories of COVID-19 publications. We did not apply any language restrictions.
SELECTION CRITERIA
Studies were eligible if they included patients with suspected COVID-19 disease, or if they recruited known cases with COVID-19 disease and controls without COVID-19. Studies were eligible when they recruited patients presenting to primary care or hospital outpatient settings. Studies including patients who contracted SARS-CoV-2 infection while admitted to hospital were not eligible. The minimum eligible sample size of studies was 10 participants. All signs and symptoms were eligible for this review, including individual signs and symptoms or combinations. We accepted a range of reference standards including reverse transcription polymerase chain reaction (RT-PCR), clinical expertise, imaging, serology tests and World Health Organization (WHO) or other definitions of COVID-19.
DATA COLLECTION AND ANALYSIS
Pairs of review authors independently selected all studies, at both title and abstract stage and full-text stage. They resolved any disagreements by discussion with a third review author. Two review authors independently extracted data and resolved disagreements by discussion with a third review author. Two review authors independently assessed risk of bias using the QUADAS-2 checklist. Analyses were descriptive, presenting sensitivity and specificity in paired forest plots, in ROC (receiver operating characteristic) space and in dumbbell plots. We did not attempt meta-analysis due to the small number of studies, heterogeneity across studies and the high risk of bias.
MAIN RESULTS
We identified 16 studies including 7706 participants in total. Prevalence of COVID-19 disease varied from 5% to 38% with a median of 17%. There were no studies from primary care settings, although we did find seven studies in outpatient clinics (2172 participants), and four studies in the emergency department (1401 participants). We found data on 27 signs and symptoms, which fall into four different categories: systemic, respiratory, gastrointestinal and cardiovascular. No studies assessed combinations of different signs and symptoms and results were highly variable across studies. Most had very low sensitivity and high specificity; only six symptoms had a sensitivity of at least 50% in at least one study: cough, sore throat, fever, myalgia or arthralgia, fatigue, and headache. Of these, fever, myalgia or arthralgia, fatigue, and headache could be considered red flags (defined as having a positive likelihood ratio of at least 5) for COVID-19 as their specificity was above 90%, meaning that they substantially increase the likelihood of COVID-19 disease when present. Seven studies carried a high risk of bias for selection of participants because inclusion in the studies depended on the applicable testing and referral protocols, which included many of the signs and symptoms under study in this review. Five studies only included participants with pneumonia on imaging, suggesting that this is a highly selected population. In an additional four studies, we were unable to assess the risk for selection bias. These factors make it very difficult to determine the diagnostic properties of these signs and symptoms from the included studies. We also had concerns about the applicability of these results, since most studies included participants who were already admitted to hospital or presenting to hospital settings. This makes these findings less applicable to people presenting to primary care, who may have less severe illness and a lower prevalence of COVID-19 disease. None of the studies included any data on children, and only one focused specifically on older adults. We hope that future updates of this review will be able to provide more information about the diagnostic properties of signs and symptoms in different settings and age groups.
AUTHORS' CONCLUSIONS
The individual signs and symptoms included in this review appear to have very poor diagnostic properties, although this should be interpreted in the context of selection bias and heterogeneity between studies. Based on currently available data, neither absence nor presence of signs or symptoms are accurate enough to rule in or rule out disease. Prospective studies in an unselected population presenting to primary care or hospital outpatient settings, examining combinations of signs and symptoms to evaluate the syndromic presentation of COVID-19 disease, are urgently needed. Results from such studies could inform subsequent management decisions such as self-isolation or selecting patients for further diagnostic testing. We also need data on potentially more specific symptoms such as loss of sense of smell. Studies in older adults are especially important
