Monte Carlo algorithm for the evaluation of the distance estimation variance in RSS-based visible light positioning

In this work, the Monte Carlo algorithm to determine the variance on the distance estimation in Received Signal Strength-based visible light positioning is considered. The method is build on the maximization of the signal-to-noise-ratio by means of matched filtering, and leads to a number of characteristics that are typically only obtained after intensive analytical elaborations. It is shown that the results match those obtained by calculating the Cramer-Rao lower bound when only the noise is considered as non-deterministic. It is demonstrated that the method is also applicable when multiple physical parameters exhibit a probability distribution, leading to an assessment of the distance estimation accuracy in more realistic settings

Nonlinear Phenomena Induced by Millijoule Femtosecond Laser Pulses at an Air-water Interface

Femtosecond laser pulses with millijoule energy have the potential to be used in many applications for remote sensing in marine environments. In this dissertation, we investigate some of the basic phenomena involved when a loosely focused, potentially filament-forming millijoule femtosecond laser pulse propagating in air interacts with an air-water interface. As an introduction to the primary investigation, we discuss concepts and experiments relevant to the primary investigation: the interaction of millijoule femtosecond laser pulses with an air-water interface. We first discuss linear femtosecond pulse propagation in water and describe an experiment investigating pulse attenuation behavior in water in the linear pulse propagation regime. We find no deviations from exponential attenuation, in contradiction to some earlier works. We then discuss nonlinear pulse propagation in water and describe an experiment investigating the onset of nonlinear pulse propagation and spectral transformation in water. We find that nonlinear femtosecond pulse propagation begins at a peak pulse intensity of about 1010 W/cm2. This experiment provides a convenient segway into the discussion and investigation of femtosecond laser filaments. We describe an experiment in which two filaments interact within liquid methanol and exchange energy. We then discuss laser- induced breakdown spectroscopy and demonstrate that different LIBS signal intensity thresholds can be utilized to image shallowly buried objects. Finally, all of these concepts are brought together to discuss the interaction of millijoule femtosecond laser pulses with an air-water interface. We catalogue and describe the main phenomena involved, which span about 12 orders of magnitude in time. We then describe the characteristics of the acoustic shockwaves generated by this interaction and demonstrate the usefulness of millijoule femtosecond laser pulses in several remote sensing applications in marine environments

Drie versies van Celan: Bernlef, Kuijper en Theunynck

This article offers an interpretation of three poems that in their title refer to Paul Celan. This evokes a theoretical reflection on the question who is responsible for the intertextuality: the author, the text or the reader. With Eco’s notion of the intentio operis it is argued that the text itself contains signals that legitimize an intertextual reading. Then, with Riffaterre, the question is answered how to discover less explicit references and architexts. In the analysis of the poems of J. Bernlef, Jan Kuijper and Peter Theunynck I will indicate which verses of Celan they are referring to and how these verses function in the new text. In addition to this it is investigated how these poems fit into the poetics of their authors. Finally the different images of Celan that these poems create are discussed. In the conclusion I will come back to the theoretical starting point of the article to determine the role of the reader in the intertextual reading

Vol. 18, No. 4

Contents: Labor Management Cooperation: Key to Organization and Employee Success, by William K. Strycker Recent Developments Further References, compiled by Margaret A. Chaplanhttps://scholarship.kentlaw.iit.edu/iperr/1069/thumbnail.jp

The effect of residual stresses on the strain evolution during welding of thin-walled tubes

In many applications, negative effects of residual stresses in the material stemming from the production process, are regularly encountered. These residual stresses in cold-rolled steel tubes are mainly due to two mechanisms: (i) the rolling of the flat plate into a circular cross-section and (ii) afterwards closing this section with a weld bead. This research focuses on the residual stresses due to the welding process. In an experimental setup abstraction is made of the real production process of the tube. A finite element model is built of this experimental setup. Validation of the welding simulations is done by comparing the strain evolution in both the experiment and the simulation. In this validation process, sometimes a discrepancy between the measured strain evolution and the one obtained from the numerical analysis is seen. In this contribution it is numerically investigated how initial residual stresses affect the thermal strain evolution in the tube during the welding process. This is done in two ways: firstly an initial stress field in hoop direction, based on the spring back of the tube when cut is taken as the reference state and secondly the stress/strain state after the first weld is used in stead of the virgin material state. The conclusion for both assumptions is that the strain evolution during the welding is affected by the initial stress/strain state of the material

Dikke boeken gedichten

Het clichébeeld wil dat gedichten verschijnen in dunne, dure boekjes met vooral erg veel wit en bijzonder weinig tekst. Daar staat paradoxaal genoeg de idee tegenover dat je voor een dichtbundel minstens even veel tijd moet uittrekken als voor een roman, misschien wel meer. Wie beide gemeenplaatsen samenneemt, moet wel tot de conclusie komen die ook Du Perron al trok: 'De Poëzie blijft, naakt en ongekromd,/een Tijdverdrijf voor enkle Fijne Luiden.' Poëzie als elitaire bezigheid voor literaire fijnproevers met te veel tijd en te veel geld dus. Afgelopen jaar verschenen er echter heel wat poëziepublicaties die dit beeld ontkrachten