986 research outputs found
Het is tijd voor één aanmeldsysteem voor alle Vlaamse scholen
No full textOpinie : 'De ene wachtrij is de andere niet', schrijven Wouter Rogiest en Bart Mesuere van de UGent. Ze pleiten voor één centraal aanmeldsysteem voor het onderwijs, en een betere timing voor de inschrijvingen
Digging through the dirt: a general method for abstract discrete state estimation with limited prior knowledge
No full textAutonomous robots are often successfully deployed in controlled environments. Operation in uncontrolled situations remains challenging; it is hypothesized that the detection of abstract discrete states (ADS) can improve operation in these circumstances. ADS are high-level system states that are not directly detectable and influence system dynamics. An example of a typical ADS problem that is used in this thesis is that of a wheeled robot driving through puddles of mud that, when entered, alters the velocity of the robot. When the robot is in such a puddle, it is in an ADS 'mud', and when it is not, it is in an ADS 'free'. ADS can be indirectly inferred through the analysis of lower-level data such as the velocity of the robot. The goal of this thesis is to design a general abstract discrete state estimator (ADSE) operating with limited prior knowledge. An ADSE is a hierarchical system for detecting changes in ADS. The ADSE should be general; applicable to multiple ADSE problems. The ADSE should further operate under limited prior knowledge: only assuming that the amount of ADS and the ADS that describes the regular operation are known. The basis for the ADSE designed in this thesis is a Gaussian hidden Markov model (GHMM), a hidden Markov model enhanced with Gaussian emissions. Randomly generated experiments are done on a simple but general ADSE problem. Two unsupervised learning methods derived from Expectation Maximization are evaluated, namely Baum-Welch (BW) and forward extraction (FWE). FWE is introduced in this thesis and is a simpler implementation of Viterbi extraction, leveraging assumptions of ADSE to in theory gain computational efficiency. We found that both BW and FWE exhibit superior performance compared to a likelihood-based baseline estimator when the maximum score of the learning curve is considered. When the final score is considered, in some cases, FWE displays a deteriorating learning curve, resulting in worse final scores compared to the baseline. Furthermore, it was found that the lower the overlap coefficient (therefore the less similar the ADS), the higher the maximum reached score. It was further shown that BW exhibits better convergence than FWE to the true model parameters. Besides this, FWE obtained comparable or in some cases even superior scores compared to BW. In general, from the results, the diversity of the experiments conducted, and the assumptions made we can conclude that the GHMM can be a general method for an ADSE with limited prior knowledge. To quantify the suitability of the GHMM for ADSE, further research should include the evaluation of different ADSE methods on the same problem. There exists a tradeoff between the lower computational cost FWE and the more stable but more computationally intensive BW learning. Therefore, future research can include a combination of these methods. Other extensions include extending the GHMM to a Gaussian mixture hidden Markov model to allow for the modeling of more complex distributions, or the application to multiple states or a changing environment.https://github.com/Wouter-deBoer/adseMechanical Engineering | Vehicle Engineering | Cognitive Robotic
embalming and reperfusion of porcine kidneys
No full text<p>These are the data of the following article:</p>
<p>Understanding Thiel embalming in pig kidneys to develop a new circulation model</p>
<p>First author: Wouter Willaert</p
Nederland op een kantelpunt: Interview met Wouter Veldhuis over het Stedelijk Netwerk Nederland en het sociaal netwerk van woonwijken
No full textDe stedenbouwkundige en architect Wouter Veldhuis en landschapsarchitect Jannemarie de Jonge zijn per 1 december 2020 Rijksadviseur voor de fysieke leefomgeving. Later in september 2021 komt daar de architect Francesco Veenstra bij als Rijksbouwmeester en dan is het nieuwe trio College van Rijksadviseurs weer compleet. De uitdagingen voor het college zijn groot. De ruimteclaims die er liggen in stad en land, de hooggestemde ambities om klimaatneutraal en circulair te zijn in 2050, de roep om een minister voor de fysieke leefomgeving en of wonen en weer een echt ministerie met budget. Het enorme probleem op de woningmarkt en de druk om één miljoen woningen ergens bij te bouwen. Op 24 april sprak het team van 1M Homes initiative van de TU Delft met de nieuw benoemde rijksadviseur voor de fysieke leefomgeving Wouter Veldhuis over de aanstaande veranderingen
A Hessenberg Markov chain for fast fibre delay line length optimization
No full textIn this paper we present an approach to compute the invariant vector of the N + 1 state Markov chain P presented in (Rogiest et al., Lecture Notes in Computer Science, NET-COOP 2007 Special Issue, pp. 4465:185-194) to determine the loss rate of an FDL buffer consisting of N lines, by solving a related Hessenberg system (i.e., a Markov chain skip-free in one direction). This system is obtained by inserting additional time instants in the sample paths of P and allows us to compute the loss rate for various FDL lengths by solving a single system. This is shown to be especially effective in reducing the computation time of the heuristic LRA algorithm presented in (Lambert et al., Proc. NAEC 2005, pp. 545-555) to optimize the FDL lengths, where improvements of several orders of magnitude can be realized
Toujours plus vite?: Youtube bientôt en haute definition?
No full textL’Internet est impensable sans fibre optique. Chaque jour, nous injectons une quantité de données extraordinaire dans les câbles en fibre optique qui constituent le réseau internet. Les séquences vidéo constituent une bonne partie de ces données. Les connecteurs qui relient les câbles ont du mal à suivre, la capacité de la fibre optique est donc largement sous-utilisée. Un Internet plus rapide passe par une amélioration de ces connecteurs
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