1,027 research outputs found
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
AIDASoft/DD4hep: v01-23
No full textv01-23
2022-09-28 Wouter Deconinck (PR#982)
ddsim: set eta_min, eta_max correctly for ddsim --gun.distribution eta
2022-09-23 Markus Frank (PR#980)
Remove using declarations in root-cling dictionary files to avoid interpreter clashes with the global namespace
Affected files:
DDCore/src/GeoDictionary.h
DDCore/src/PropertyDictionary.h
DDCore/src/RootDictionary.h
DDCore/src/SegmentationDictionary.h
DDEve/include/DDEve/Dictionary.h
DDG4/include/DDG4/DDG4Dict.h
2022-09-23 Marco Clemencic (PR#979)
Use explicit namespaces in DDCond dictionary
2022-09-19 Wouter Deconinck (PR#976)
geoConverter -compact2tgeo to write TGeo geometry to ROOT file
2022-09-19 Christopher Dilks (PR#974)
add example RICH detector, demonstrating and testing Geant4OpticalTrackerAction
2022-09-16 Wouter Deconinck (PR#975)
materialBudget: enable use with asymmetric detectors: adding thetaMin/thetaMax/etaMin to the steering file
2022-09-15 Wouter Deconinck (PR#967)
Geant4OpticalTrackerAction which stops-and-kills optical photons for e.g. SiPM sensor planes
2022-09-12 Christopher Dilks (PR#973)
fix typo in examples/README.md: cmake option DD4HEP_BUILD_EXAMPLES should be DD4HEP_EXAMPLES
2022-09-07 Dmitry Kalinkin (PR#972)
Refactor thisdd4hep.sh to use local variables where possible to prevent user environment corruption.
2022-09-01 Andre Sailer (PR#969)
DDSim: ddsim now prints out if the defaultFilter or if no filter is used for a sensitive detector
2022-09-01 Wouter Deconinck (PR#968)
ddsin: Add --runType qt support for enabling the graphical Qt interface for geant4
ddsim: change shell type to tcsh: enabling tab completion when Geant4 offers it
2022-08-26 Andre Sailer (PR#962)
DDCore: DetectorInfo: make INFO attributes optional, fixes #960
2022-08-25 Andre Sailer (PR#963)
ChannelingCrystalMaterial: fix crystal_orientation to be constPropertyRef
2022-08-25 Andre Sailer (PR#961)
DDSim: fix example for adding user physics list extensionwebpage: http://dd4hep.cern.ch
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
Does Indonesia have a"low-pay"civil service?
No full textGovernment officials and polcy analysts maintain that Indonesia's civil servants are poorly paid and have been for decades. This conclusion is supported by anecdotal evidence and casual empiricism. The authors systematically analyze the realtionship between government and private compensation levels using data from two large household surveys carried out by Indonesia's Central Bureau of Statistics: the 1998 Sakernas and 1999 Susenas. The results suggest that government workers with a high school education or less, representing three-quarters of the civil service, earn a pay premium over their private sector counterparts. Civil servants with more than a high school education earn less than they would in the private sector but, on average, the premium is far smaller than commonly is alleged and is in keeping with public/private differentials in other countries. These results prove robust to varying econometric specifications and cast doubt on low pay as an explanation for government corruption.Decentralization,Public Health Promotion,Health Monitoring&Evaluation,National Governance,Knowledge Economy,Health Monitoring&Evaluation,NationalGovernance,Knowledge Economy,Education for the Knowledge Economy,Parliamentary Government
Characterisation and Modelling of Residential Electricity Demand
No full textDemand side management is regaining attention because of the integration of intermittent renewable energy sources such as wind and solar power. Accurate electrical load data are needed to estimate the potential and the impact of demand response. Data itself is hard to grasp. Analytical techniques are required to describe the data in a comprehensive way. Privacy laws prevent data usage in certain contexts. Data modelling gets around the privacy problem and allows for Monte Carlo simulations.First, residential electricity demand is described. The demographic properties describing the electricity demand in Belgium are determined with the use of machine learning techniques. Residential electricity consumers are grouped based on timing of and amount of electricity demand with clustering techniques. Measurement data from a project are scaled up by employing the groups found to get an impression of electricity demand of wet appliances.Then, residential electricity demand is modelled. The combination of electricity consumer groups together with Markov models allow for an electricity demand model. Wet appliance load cycles are detected and parametrised according to the previously defined consumer groups. The first is able to regenerate load data at the household connection point, the latter is able to regenerate load cycles of appliances.Finally, the models are applied to estimate potential and impact of direct appliance control and corresponding privacy issues.status: Publishe
Optimization of the capacity of a rose sorting system using discrete event simulation
No full textIn Rose cultivation companies in the Netherlands, there is a demand for a higher sorting capacity on the existing sorting systems. The objective for this research is to advice which part of the sorting system needs to be adjusted to gain a higher sorting capacity. For the current sorting systems, five bottlenecks are defined, the bottlenecks limit the sorting capacity. To be able to forecast the effect of machine adjustments, a discrete event simulation model has been constructed, using Simulink and Matlab. This simulation model is verified, matched and validated using data of on an existing rose sorting system. Results of a single day validation showed that the time to process the roses can be simulated with a 97% accuracy. Subsequently, five different simulations are executed. In each simulation, one of the five bottlenecks is removed or reduced. With the results of these simulations the capacity limitation due to each bottleneck is quantified. However entirely removing a bottleneck is not feasible in reality for all bottlenecks. A last situation is simulated where all feasible bottleneck reductions are combined. This showed that the time to sort all roses is reduced by 35%.Marine Technology | Transport Engineering and Logistic
The Search for Exotic Baryons at the HERMES Experiment.
No full textOne of the interesting questions of Quantum Chromodynamics, the theory that governs the interactions between quarks and gluons, has been whether it is possible to observe hadrons which can not be explained as a combination of only two or three valence quarks. In numerous searches the existence of these exotic hadrons could not be confirmed. Recently, calculations based on the quark soliton model predicted the narrow exotic baryons Theta+ and Xi--. A narrow resonance identified as the Theta+ was observed by several experiments at the predicted mass of 1540 MeV, but later followed by several dedicated experiments that could not confirm these positive results.
At the HERMES experiment a search for the quasi-real photoproduction of the exotic baryon Theta+ on a deuterium target and the subsequent decay through p K0(S) to p pi+ pi- revealed a narrow resonance in the p K0(S) invariant mass distribution at 1528 MeV. In the search for the corresponding antiparticle Theta- the result is consistent with zero events.
In this thesis we present the search for the exotic baryon Xi-- on a deuterium target in the data sample used for the observation of the Theta+. An upper limit on the cross section of the exotic baryon Xi-- is determined. The search for the exotic baryon Theta+ on hydrogen and deuterium targets at the HERMES experiment is extensively discussed. The event mixing method can be used to estimate the distribution of background events. Several difficulties with this method were addressed, but the background description in the case of the exotic baryon Theta+ remains unconvincing. Between the years 2002 and 2005 the HERMES experiment operated with a magnetic holding field around the hydrogen target. A method for the reconstruction of displaced vertices in this field was developed. The data collected during the years 2006 and 2007 offer an integrated luminosity that is several times higher than in previous data sets. After investigating all data sets collected with the HERMES experiment on hydrogen and deuterium targets, we are not able to observe a resonance peak at an invariant mass of 1540 MeV consistent with the exotic baryon Theta+.PhDPhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/58519/1/wdconinc_1.pd
Single-component organic solar cells-Perspective on the importance of chemical precision in conjugated block copolymers
No full textThe author(s) declare financial support was received for the research, authorship, and/or publication of this article. The authors acknowledge financial support from Hasselt University, the Research Foundation-Flanders (FWO Vlaanderen; projects W000620N, I006320N, and 1S99620N), and the European Research Council (ERC; grant agreement 864625)
From exemplar to copy: the scribal appropriation of a Hadewijch manuscript computationally explored
No full textThis study is devoted to two of the oldest known manuscripts in which the
oeuvre of the medieval mystical author Hadewijch has been preserved: Brussels,
KBR, 2879-2880 (ms. A) and Brussels, KBR, 2877-2878 (ms. B). On the basis of
codicological and contextual arguments, it is assumed that the scribe who
produced B used A as an exemplar. While the similarities in both layout and
content between the two manuscripts are striking, the present article seeks to
identify the differences. After all, regardless of the intention to produce a
copy that closely follows the exemplar, subtle linguistic variation is
apparent. Divergences relate to spelling conventions, but also to the way in
which words are abbreviated (and the extent to which abbreviations occur). The
present study investigates the spelling profiles of the scribes who produced
mss. A and B in a computational way. In the first part of this study, we will
present both manuscripts in more detail, after which we will consider prior
research carried out on scribal profiling. The current study both builds and
expands on Kestemont (2015). Next, we outline the methodology used to analyse
and measure the degree of scribal appropriation that took place when ms. B was
copied off the exemplar ms. A. After this, we will discuss the results
obtained, focusing on the scribal variation that can be found both at the level
of individual words and n-grams. To this end, we use machine learning to
identify the most distinctive features that separate manuscript A from B.
Finally, we look at possible diachronic trends in the appropriation by B's
scribe of his exemplar. We argue that scribal takeovers in the exemplar impacts
the practice of the copying scribe, while transitions to a different content
matter cause little to no effect
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