2,643 research outputs found
Rondo Pour Piano-Forte dédié `a son Elive Mademoiselle Caroline Hartmann
No full textRONDO POUR PIANO-FORTE DÉDIÉ `A SON ELIVE MADEMOISELLE CAROLINE HARTMANN
Rondo Pour Piano-Forte dédié `a son Elive Mademoiselle Caroline Hartmann (1)
Titelseite (1)
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Up or down? Resolving agreement in copular sentences
No full textThese files contain the anonymised raw data from 7 experiments developed and run for the BA-funded project "Up or Down? Resolving agreement in copular clauses. There are 2 sets of data - one from a production task and one from a grammaticality judgment task - for each of Dutch, German, and Faroese. There is 1 set of data from a grammaticality judgment task for Icelandic.
The study investigated possible patterns of agreement in copular sentences in which there were two nominals different in either person or number or both (e.g. "The source of the rumour was/were your neighbours"; "My only hope is/are you"). The particular focus of the study was the possible contrasts between agreement with 3rd person pronouns and non-3rd person pronouns ("The problem is/are they" vs "The problem is/are you"). In all of the languages investigated in the study (Dutch, German, Faroese, Icelandic) prior research indicated that at least some speakers produce agreement for number with the second noun phrase ("The source of the rumour were your neighbours") in contrast to English, where agreement with the first noun phrase is strongly preferred. What this study adds is information about possibilities for person agreement.README.txt A summary of the contents of all the data files
FAR01Prod.csv Data from the production (cloze task) study on Faroese agreement
FAR01Rating.csv Data from the rating study ("thermometer rating") on Faroese agreement
GER02Prod.csv Data from the production (cloze task) study on German agreement
GER02Rating.csv Data from the rating study ("thermometer rating") on German agreement
ICE01Rating.csv Data from the rating study ("thermometer rating") on Icelandic agreement
NL02Prod.csv Data from the production (cloze task) study on Dutch agreement
NL02Rating.csv Data from the rating study ("thermometer rating") on Dutch agreemen
Magnetohydrodynamic turbulence in a Hartmann duct flow at finite magnetic Reynolds number
No full textThe dynamics of turbulent flow at finite magnetic Reynolds numbers can be very complex due to the coupled nature of the evolution equations for the flow and magnetic fields. In this regime, the Hartmann flow in a straight rectangular duct with streamwise periodicity is studied with the help of direct numerical simulations (DNS) and the effect of magnetic Reynolds number on turbulent statistics is quantified by comparing the results with the numerical results obtained using the quasistatic approximation
Shack-Hartmann reflective micro profilometer
No full textWe present a quantitative phase imaging microscope based on a Shack-Hartmann sensor, that directly reconstructs the optical path difference (OPD) in reflective mode. Comparing with the holographic or interferometric methods, the SH technique needs no reference beam in the setup, which simplifies the system. With a preregistered reference, the OPD image can be reconstructed from a single shot. Also, the method has a rather relaxed requirement on the illumination coherence, thus a cheap light source such as a LED is feasible in the setup. In our previous research, we have successfully verified that a conventional transmissive microscope can be transformed into an optical path difference microscope by using a Shack-Hartmann wavefront sensor under incoherent illumination. The key condition is that the numerical aperture of illumination should be smaller than the numerical aperture of imaging lens. This approach is also applicable to characterization of reflective and slightly scattering surfaces.Team Raf Van de Pla
Deep Learning Wavefront Sensing: Via Raw Shack-Hartmann Images
No full textThe Delft Center for Systems and Control (DCSC) 'Smart Optics' aim to achieve higher resolution imaging through Adaptive Optics (AO). Adaptive optics is a modern technique for detecting and correcting real-time wavefront aberrations and is widely used in biomedical imaging and astronomical imaging. Wavefront sensing lies at the core of Adaptive Optics and is known to pose some challenges. Measurement of the wavefront cannot be done directly and has to be estimated through an intensity distribution on a detector. One approach to wavefront sensing is by using a Shack-Hartmann (SH) sensor. A Shack-Hartmann sensor (a pupil-plane sensor) subdivides the wavefront into N spatial areas using sub-apertures. The individual slopes across all sub-apertures are integrated to reconstruct the wavefront. The major advantage of using a Shack-Hartmann sensor is its fast operation speed, caused by the linear relationship between local slopes and original wavefront. This enables real-time wavefront reconstruction. The Shack-Hartmann sensor however, has some limitations. Its ability to reconstruct higher-order aberrations is restricted by the amount of lenses within the micro-lens array. Furthermore, a centroiding algorithm is used to compute the local slopes. Going from spots to centroids decreases the amount of informative pixels and greatly limits its wavefront reconstruction potential. Moreover, these centroiding algorithms often add a measure of uncertainty since spots can have irregular shapes or cross-over/overlap. In this Master Thesis a novel approach to phase reconstruction from the raw SH measurement is proposed. Here, we show that Deep Learning techniques in combination with a micro-lens array can surpass traditional SH phase reconstruction methods and alleviate their current limitations. The proposed method uses the entire Shack-Hartmann Pattern (HP) as input to a neural network, supplying the network with more information than existing Deep Learning SHWR methods, which still rely on centroids. Using this approach, we can combine the accuracy of sensor-less techniques with the speed of a Shack-Hartmann sensor. Three different neural network architectures are considered in this thesis. Two of these neural networks (Alex-Net and Xception) are adapted to output a series of Zernike coefficients. Using these estimated Zernike coefficients, a wavefront can be reconstructed. The remaining neural network, U-Net, performs a direct pixel-wise estimation of the phase-map. The input Shack-Hartmann patterns are created using different micro-lens array (MLA) geometries, consisting of 25-, 256- or 900 lenses. The networks are evaluated on their ability to reconstruct a combination of 32- or 100- Zernike coefficients.Mechanical Engineering | Systems and Contro
Estimation of the total error of modal wavefront reconstruction with Zernike polynomials and Hartmann-Shack test
No full textThe paper discusses the influence of the Hartmann-(Shack) wavefront sensor geometry on the total error of modal wavefront reconstruction. A mathematical model is proposed which describes modal wavefront reconstruction based on Hartmann or Hartmann-Shack sensor in terms of linear operators. The modal covers the most general case and is not limited by the orthogonality of decomposition basis or by the method chosen for decomposition. The total reconstruction error is calculated for any given statistics of the wavefront to be measured. Based on this estimate, total reconstruction error is calculated for regular and randomised Hartmann masks. The calculations demonstrate that use of random masks with non-regular Fourier spectra for Zernike wavefront reconstruction for atmospheric turbulence allows to double the number of decomposition modes with the same total error.Electronic InstrumentationElectrical Engineering, Mathematics and Computer Scienc
Information structural notions and the fallacy of invariant correlates
No full textIn a first step, definitions of the irreducible information structural categories are given, and in a second step, it is shown that there are no invariant phonological or otherwise grammatical correlates of these categories. In other words, the phonology, syntax or morphology are unable to define information structure. It is a common mistake that information structural categories are expressed by invariant grammatical correlates, be they syntactic, morphological or phonological. It is rather the case that grammatical cues help speaker and hearer to sort out which element carries which information structural role, and only in this sense are the grammatical correlates of information structure important. Languages display variation as to the role of grammar in enhancing categories of information structure, and this variation reflects the variation found in the ‘normal’ syntax and phonology of languages
Correction to:Characterization, modeling, and remediation of karst in a changing environment (Environmental Earth Sciences, (2018), 77, 12, (476), 10.1007/s12665-018-7660-7)
No full textIn the original publication, the author name Andrew Hartmann was published incorrectly. The correct name should be Andreas Hartmann.</p
Terahertz wavefronts measured using the Hartmann sensor principle
No full textWe demonstrate for the first time that the Hartmann wavefront sensor (HWS) principle can be applied for characterizing the wavefronts of terahertz (THz) electromagnetic radiation. The THz Hartmann wavefront sensor consists of a metallic plate with an array of holes and a twodimensional scanable pyro-electric detector. The THz radiation with different wavefronts was generated by a far-infrared gas laser operated at 2.5 THz in combination with a number of objects that result in known wavefronts. To measure the wavefront, a beam passing through an array of holes generates intensity spots, for which the positions of the individual spot centroids are measured and compared with reference positions. The reconstructed wavefronts are in good agreement with the model expectations.QN/Quantum NanoscienceApplied Science
Intuizione e conoscenza in Nicolai Hartmann (1911-1926). Sulle premesse dell'ontologia critica
No full textIntuition and Knowledge in Nicolai Hartmann (1911-1926). On the Premises of Critical Ontology. The author considers Nicolai Hartmann’s main points on the relationship between intuition and knowledge in his early and middle works (1911-1926). The author first shows how Hartmann’s critical ontology emerged as a reaction to the approach of the logical idealism of the Marburg School, against which Hartmann defends the existence of an irrational dimension of knowledge that legitimizes a minimum of metaphysics even in the gnoseological sphere. The author then focuses on the way in which Hartmann interprets the relationship between intuition and givenness, apriority, status of a priori principles, and understanding. Hartmann argues that intuition is not exclusively the same as empirical intuition, and that the problem of knowledge should no longer be considered in terms of the distinction between sensibility and understanding, but through the difference between a priori and a posteriori knowledge
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