No description available.

No description available.

Inaug.-dis.--Würzburg.

A novel sensing methodology using two-axis Hall-effect sensors is proposed, where the absolute positioning of a device atop any magnet matrix is possible. This methodology has the capability of micrometer-order positioning resolution as well as unrestricted translational and rotational range in planar 3-DOF (degree-of-freedom) motions, with potential capability of measuring all 6-DOF motions. This research presents the methodology and preliminary experimental results of 3-DOF planar motion measurements atop a Halbach magnet matrix using two sets of two-axis Hall-effect sensors. Analysis of the Halbach magnet matrix is presented to understand the generated magnetic field. The algorithm uses the Gaussian least squares differential correction (GLSDC) algorithm to estimate the relative position and orientation from the Hall-effect sensor measurements. A recursive discrete-time Kalman filter (DKF) is used in combination with the GLSDC to obtain optimal estimates of position and orientation, as well as additional estimates of velocity and angular velocity, which we can use to design a multivariable controller. The sensor and its algorithm is implemented to a magnetic levitation (maglev) stage positioned atop a Halbach magnet matrix. Preliminary experimental results show its position resolution capability of less than 10 µm and capable of sensing large rotations. Controllers were designed to close the control loop for the three planar degrees of freedom motion using the GLSDC outputs at a sampling frequency of 800 Hz on a Pentek 4284 digital signal processor (DSP). Calibration was done by comparing the laser interferometers’ and the GLSDC’s outputs to improve the positioning accuracy.

InN thin films were grown on £^-LiAlO2 (100) by plasma-assisted molecular-beam epitaxy (PAMBE). Structural properties were investigated by reflective high-energy electron diffraction (RHEED), x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). XRD measurements showed that the crystal orientation of InN films was non-polar m-plane (11 ¡Â00). In addition, from SEM images, a striped morphology was observed along [112 ¡Â0]. Optical properties were characterized by photoluminescence (PL) spectroscopy, cathodoluminescence (CL) spectroscopy and micro-Raman scattering. Both CL/PL results revealed that InN films have a luminescence-emission peak-energy of about 0.65 eV. Carrier concentration had been determined by Hall measurements.

Techn. Univ., Diss.--Braunschweig, 2006. / Auch als elektronisches Dokument.

Reproduction de : Thèse de docteur-ingénieur : sciences : Grenoble 1 : 1959. / Titre provenant de l'écran-titre. Bibliogr. p. 86-87.

The Salt Silo in Tvøroyri, The Faroe Islands, is set to be turned the largest concert hall in The Faroe Islands. The Salt Silo is a large old silo with wood and concrete walls, and currently acoustics which are not suitable for musical reproduction. The project leaders require the concert hall to be suitable for both classical and rock music, which poses an interesting acoustical challenge. In this paper I will go through which variables should be known and controlled to be able to acoustically analyze and design a concert hall such as The Salt Silo. To not become too large of a project, the paper will focus on the hall's lateral energy fraction and reverberation time. The paper will also look at the Clarity Index parameter (C80) and note how it is affected by the change of reverberation time. The concert hall will be simulated with Odeon auralization software by Brüel & Kjær, and the paper will present the author's suggestion of how the concert hall should be acoustically designed to optimize the values of the reverberation time and lateral energy fraction. The design objective is to create a hall which is suitable for classical music, but where the acoustics can be varied to be able to house modern rock concerts as well. The paper will present a suggestion as to how The Salt Silo should be transformed from an old silo to a modern concert hall which fulfills the criteria which the project leaders have set on reverberation time and lateral energy fraction.

Not available / text

I denna studie undersöks hur romer representeras i media. Detta görs utifrån två aktuella nyhetshändelser under 2013 där jag söker svar på vilka som får framträda i artiklarna, vilka nyckelord som används i texterna samt hur romer representeras genom en bildanalys.  En jämförelse görs också historiskt med tidigare skildringar av romer för att se om representationen av romer är liknande sedan tidigare. Jag blev intresserad att göra denna studie om romer och media då romer inte alltför längesedan blivit en erkänd minoritetsgrupp men som historiskt varit en väldigt utsatt grupp i Sverige och länder runt om i Europa.  Resultatet av studien visar att romer idag beskrivs med liknande negativa konnotationer som de gjort historiskt men att detta inte uttrycks i media på samma sätt idag. Skillnaden mellan hur romer representeras idag och under tidigt 1900-tal är att det förut skrevs öppet negativt om romer – idag används inte språkbruket för att identifiera romer utan det uttrycks mellan raderna.