Classical and Bayesian Linear Data Estimators for Unique Word OFDM

Unique word - orthogonal frequency division multiplexing (UW-OFDM) is a novel OFDM signaling concept, where the guard interval is built of a deterministic sequence - the so-called unique word - instead of the conventional random cyclic prefix. In contrast to previous attempts with deterministic sequences in the guard interval the addressed UW-OFDM signaling approach introduces correlations between the subcarrier symbols, which can be exploited by the receiver in order to improve the bit error ratio performance. In this paper we develop several linear data estimators specifically designed for UW-OFDM, some based on classical and some based on Bayesian estimation theory. Furthermore, we derive complexity optimized versions of these estimators, and we study their individual complex multiplication count in detail. Finally, we evaluate the estimators' performance for the additive white Gaussian noise channel as well as for selected indoor multipath channel scenarios.Comment: Preprint, 13 page

Music education - action and prejudice: an experimental study about the influence of status on the evaluation of music teaching

Die vorliegende Studie ist Teil des Forschungsprojekts OSIRIS zur Wahrnehmung von Musikunterricht. In diesem Projekt gehen [die Autoren] von der These aus, dass die Fähigkeit der Unterrichtsbeobachtung ein grundlegender Bestandteil der professionellen Kompetenz von Lehrern ist. Langfristig zielen [die] Forschungsvorhaben auf geeignete Interventionsstudien ab. Dabei wird mittels videobasierter Testverfahren untersucht, inwieweit die Fähigkeit der Unterrichtsbeobachtung bei zukünftigen Lehrern bereits im Studium durch gezielte Trainings verbessert werden kann. In der Pilotstudie OSIRIS I wurden grundlegende Wahrnehmungsdimensionen bei der Beobachtung von Musikunterricht untersucht. Die Analyse der quantitativen und qualitativen Daten zeigt, dass der Wahrnehmungsraum von Musikunterricht in erster Linie durch allgemein-pädagogische Dimensionen geprägt ist. Während Lehrende eher pädagogisch-methodische Anmerkungen machen, spielen in der Wahrnehmung des Musikunterrichts bei Schülern musikbezogene Aspekte eine Rolle. Mittels einer multidimensionalen Skalierung konnten die Dimensionen Aufmerksamkeit, Kooperation und Musizieren in einer dreidimensionalen Beschreibung des Wahrnehmungsraums von Musikunterricht dargestellt werden. Den abschließenden Gedächtnistest bewältigten die Lehrer besser, als die Studenten oder Schüler. Unsere Folgestudie OSIRIS II geht der Frage nach, inwieweit Vorurteile einen Wahrnehmungsfilter bilden. (DIPF/Orig.)So far, there have been no studies of music pedagogy which focus on the topic of prejudice influencing the appraisal of music teaching. Our study deals with the question “to what extent can prejudice influence the perception and appraisal of music lessons?” The appraisal of teachers by students may be influenced by many preconceptions. For example, the teacher’s status – whether the music teaching is being performed by a non-specialist teacher or the head of a musical department; or the level of experience of the teacher – a novice, prospective teacher, as opposed to a seasoned expert. The appraisal of music teaching is also likely to depend on the type of school (lower secondary school versus high school/ grammar school). (DIPF/Orig.

"Studying music education is making me sick". An empirical study on the predictability of motivation effects on burnout among students of school education

Lehrer müssen im Vergleich zu anderen Berufsgruppen mit Abstand die größten psychischen Belastungen bewältigen. Dies zeigt sich auch in einem drastischen Anstieg von Arbeitsunfähigkeitstagen aufgrund psychischer Belastungen und durch das Burnout‐Syndrom. Besonders stressinduzierend scheint das Unterrichtsfach Musik zu sein. Im Vergleich zu Kollegen mit anderen Fächern erleiden Lehrer mit dem Fach Musik am häufigsten ein Burnout. Die meisten der ausgebrannten Lehrer fühlten sich bereits im Studium überfordert. In der aktuellen Situation von Bachelor‐Studierenden ist der Prozess von Burnout schon während des Studiums ein gravierendes Problem. Jeder dritte Student bringt ein problematisches Belastungsprofil mit in das Lehramtsstudium und viele betroffene Studierende weisen ungünstige Bewältigungsstile auf. Bisher liegen nur wenige forschungsrelevante Untersuchungen zu Burnout bei Schulmusikstudierenden vor. Eine Burnout‐Prävention ist daher bereits im Schulmusikstudium sinnvoll. Voraussetzung dafür ist zunächst die Durchführung von Grundlagenstudien zu möglichen Ursachen und Einflüssen, welche eine Stressbewältigung verhindern oder begünstigen. Die vorliegende Studie will dazu einen Beitrag leisten, indem sie im musikpädagogischen Kontext der Frage nachgeht, ob die Motivation musikpädagogischen Handelns einen Einfluss auf Burnout bei Schulmusikstudierenden hat. (DIPF/Orig.)In comparison to their colleagues who teach other subjects, music teachers most frequently suffer from burnout. Most teachers diagnosed with burnout already felt mentally overstrained during their studies. To date, only a few research studies on burnout suffered by music education students have been carried out. This study illustrates the positive influence of motivation on managing music education student stress levels (N=238) in a structural equation model. Teaching experiences encourage the motivation to study music education. When combined with a high degree of self‐regulation, it leads to an increase in educational achievement. If this process is indicative of an overall development, it could signify a positive prognosis for burnout prevention. (DIPF/Orig.

Component-wise conditionally unbiased widely linear MMSE estimation

AbstractBiased estimators can outperform unbiased ones in terms of the mean square error (MSE). The best linear unbiased estimator (BLUE) fulfills the so called global conditional unbiased constraint when treated in the Bayesian framework. Recently, the component-wise conditionally unbiased linear minimum mean square error (CWCU LMMSE) estimator has been introduced. This estimator preserves a quite strong (namely the CWCU) unbiased condition which in effect sufficiently represents the intuitive view of unbiasedness. Generally, it is global conditionally biased and outperforms the BLUE in a Bayesian MSE sense. In this work we briefly recapitulate CWCU LMMSE estimation under linear model assumptions, and additionally derive the CWCU LMMSE estimator under the (only) assumption of jointly Gaussian parameters and measurements. The main intent of this work, however, is the extension of the theory of CWCU estimation to CWCU widely linear estimators. We derive the CWCU WLMMSE estimator for different model assumptions and address the analytical relationships between CWCU WLMMSE and WLMMSE estimators. The properties of the CWCU WLMMSE estimator are deduced analytically, and compared by simulation to global conditionally unbiased as well as WLMMSE counterparts with the help of a parameter estimation example and a data estimation/channel equalization application

Performance Characteristics of an 8 MW(th) Combined Heat and Power Plant Based on Dual Fluidized Bed Steam Gasification of Solid Biomass

The work focuses on a dual fluidized bed gasification technology for which a model has been developed and validated accompanying the operation of the 8 MWth biomass combined heat and power plant in Guessing/Austria. The reactor concept is a circulating fluidized bed system with a large steam-fluidized bubbling bed integrated into the solids return loop. The solids circulation rate is shown versus the riser exit velocity. Further, plant performance maps are presented for both electric and heat power output. The water content of the fuel is a major parameter with respect to plant performance. High fuel water content at high gas engine load means high gas velocities in the riser (erosion limit) and higher heat share in the produced energy

Design and analysis of UW-OFDM signals

AbstractUnique word-orthogonal frequency division multiplexing (UW-OFDM) is a novel signaling concept where the guard interval is implemented as a deterministic sequence, the so-called unique word. The UW is generated by introducing a certain level of redundancy in the frequency domain. Different data estimation strategies and the favourable bit error ratio (BER) performance of UW-OFDM, as well as comparisons to competing concepts have already extensively been discussed in previous papers. This work focuses on the different possibilities on how to generate UW-OFDM signals. The optimality of the two-step over the direct approach in systematic UW-OFDM is proved analytically, we present a heuristic algorithm that allows a fast numerical optimization of the redundant subcarrier positions, and we show that our original intuitive approach of spreading the redundant subcarriers in systematically encoded UW-OFDM by minimizing the mean redundant energy is practically also optimum w.r.t. transceiver based cost functions. Finally, we derive closed form approximations of the statistical symbol distributions on individual subcarriers as well as the redundant energy distribution and compare them with numerically found results

Similarity based cooperation and spatial segregation

We analyze a cooperative game, where the cooperative act is not based on the previous behaviour of the co-player, but on the similarity between the players. This system has been studied in a mean-field description recently [A. Traulsen and H. G. Schuster, Phys. Rev. E 68, 046129 (2003)]. Here, the spatial extension to a two-dimensional lattice is studied, where each player interacts with eight players in a Moore neighborhood. The system shows a strong segregation independent on parameters. The introduction of a local conversion mechanism towards tolerance allows for four-state cycles and the emergence of spiral waves in the spatial game. In the case of asymmetric costs of cooperation a rich variety of complex behavior is observed depending on both cooperation costs. Finally, we study the stabilization of a cooperative fixed point of a forecast rule in the symmetric game, which corresponds to cooperation across segregation borders. This fixed point becomes unstable for high cooperation costs, but can be stabilized by a linear feedback mechanism.Comment: 7 pages, 9 figure