@book{40012, author = {{Blumberg, Eva}}, title = {{{Multikriteriale Zielerreichung im naturwissenschaftsbezogenen Sachunterricht der Grundschule – Eine Studie zum Einfluss von Strukturierung in schülerorientierten Lehr-Lernumgebungen auf das Erreichen kognitiver, motivationaler und selbstbezogener Zielsetzungen. Inaugural-Dissertation zur Erlangung des akademischen Grades des Doktors in den Erziehungswissenschaften an der Westfälischen Wilhelms-Universität Münster}}}, year = {{2008}}, } @inbook{40419, author = {{Grotjahn, Rebecca}}, booktitle = {{Gattungsgeschichte als Kulturgeschichte. Festschrift für Arnfried Edler}}, editor = {{Siegert, Christine and Hottmann, Katharina and Meine, Sabine and Loeser, Martin and Fischer, Axel}}, isbn = {{978-3-487-13636-3}}, pages = {{149–162}}, publisher = {{Georg Olms}}, title = {{{Rätsel und Lektüren: Zur Zyklizität von Robert Schumanns Liederkreis Myrthen op. 25}}}, volume = {{3}}, year = {{2008}}, } @inbook{40418, author = {{Grotjahn, Rebecca}}, booktitle = {{Feste - Opern - Prozessionen}}, editor = {{Hottmann, Katharina and Siegert, Christine }}, pages = {{155–157}}, publisher = {{Georg Olms}}, title = {{{Fundstück: Musikwissenschaftliche Genderforschung im 19. Jahrhundert?}}}, volume = {{1}}, year = {{2008}}, } @inbook{40424, author = {{Grotjahn, Rebecca}}, booktitle = {{Performativität und Performance. Geschlecht in Musik, Theater und MedienKunst}}, editor = {{Oster, Martina and Ernst, Waltraud and Gerards, Marion }}, isbn = {{978-3-8258-0660-6 }}, pages = {{299–309}}, publisher = {{LIT Verlag}}, title = {{{Eine ‚Stimme von fast männlicher Färbung – Zarah Leander und die nationalsozialistische Geschlechterordnung}}}, volume = {{8}}, year = {{2008}}, } @inbook{40421, author = {{Grotjahn, Rebecca}}, booktitle = {{Wider die Frau. Zur Geschichte und Funktion misogyner Rede}}, editor = {{Geier, Andrea and Kocher, Ursula}}, pages = {{37–58}}, publisher = {{Böhlau}}, title = {{{Der Wirkungskreis des Weibes. Zur Funktion frauenfeindlicher Rede in der Zauber­flöte}}}, volume = {{33}}, year = {{2008}}, } @inproceedings{40865, abstract = {{In this paper we study space-time coding schemes for a novel MIMO transceiver which performs adaptive signal combining in radio-frequency (RF). The limitations of the RF circuitry make necessary to develop specific designs for this architecture. For instance, the space and time encoders must operate separately (the former works in the RF domain and the latter works in baseband), and at different time scales: the spatial encoder or RF beamformer must remain fixed dur- ing the transmission of a probably large number of symbols, whereas the time-encoder can work at the symbol rate. We show in the paper that although the multiplexing gain of the system is limited to one, we are still able to achieve the full spatial diversity of the MIMO channel as well as to increase the received signal-to-noise ratio through array gain. Specifically, when perfect channel state information (CSI) is available only at the receiver we propose to use a scheme referred to as orthogonal beam division multiplexing (OBDM). With this scheme the symbols are time-precoded with a unitary discrete Fourier transform (DFT) matrix, then they are successively transmitted through orthogonal direc- tions and, finally, we use a receiver comprising maximal ra- tio combining (MRC) followed by a minimum mean-square error (MMSE) decoder. The performance of the proposed techniques in terms of outage capacity and bit error rate is illustrated by means of several simulations examples.}}, author = {{Santamaría, I. and Elvira, V. and Vía, J. and Ramírez, D. and Pérez, J. and Ibáñez, J. and Eickhoff, R. and Ellinger, F.}}, booktitle = {{Proc.\ Eur.\ Signal Process.\ Conf.}}, title = {{{Optimal MIMO transmission schemes with adaptive antenna combining in the RF path}}}, year = {{2008}}, } @article{40872, abstract = {{We study continuous-time multidimensional wide- sense stationary (WSS) and (almost) cyclostationary processes in the frequency domain. Under the assumption that the correlation function is uniformly continuous, we prove the existence of a unique sequence of spectral measures, which coincide with the restrictions to certain subdiagonals of the spectral measure in the strongly harmonizable case. Moreover, the off-diagonal measures are absolutely continuous with respect to the diagonal measure. As a consequence, for strongly harmonizable scalar improper almost cyclostationary processes, we obtain representation formulas for the components of the complementary spectral measure and the off-diagonal components of the spectral measure, in terms of the diagonal component of the spectral measure. We apply these results to analytic signals, which produces sufficient conditions for propriety for almost cyclostationary analytic signals.}}, author = {{Wahlberg, Patrik and Schreier, Peter J.}}, journal = {{IEEE Trans.\ Inform.\ Theory}}, number = {{4}}, pages = {{1670–1682}}, title = {{{Spectral Relations for Multidimensional Complex Improper Stationary and (Almost) Cyclostationary Processes}}}, doi = {{10.1109/TIT.2008.917626}}, volume = {{54}}, year = {{2008}}, } @article{40860, abstract = {{This paper deals with the analysis and design of orthogonal frequency-division multiplexing interleave-division multiple-access (OFDM-IDMA). We begin with the analysis of the information-theoretical advantages of non-orthogonal transmission schemes in fading multiple-access channels. We then turn attention to practical design issues. A signal-to-noise ratio (SNR) evolution technique is developed to predict the bit-error-rate (BER) performance of OFDM-IDMA. This technique is applied to system design and optimisation. Through proper power allocation, OFDM-IDMA can achieve the multi-user gain (MUG) predicted by information-theoretical analysis. It is also an attractive option in compensating for the clipping effect caused by peak-power limitation. Numerical examples show that OFDM-IDMA can (i) alleviate the PAPR problem commonly suffered by OFDM-based schemes; (ii) deliver significant MUG compared with other orthogonal alternatives; (iii) provide robust communications in frequency-selective channels; and (iv) support high single-user throughput. Copyright {\copyright} 2008 John Wiley & Sons, Ltd.}}, author = {{Tong, Jun and Guo, Qinghua and Ping, Li}}, journal = {{European Trans.\ Comm.}}, number = {{5}}, pages = {{561–569}}, publisher = {{John Wiley & Sons}}, title = {{{Analysis and design of OFDM-IDMA systems}}}, doi = {{10.1002/ett.1304}}, volume = {{19}}, year = {{2008}}, } @article{40870, abstract = {{The assessment of multivariate association between two complex random vectors is considered. A number of correlation coefficients based on three popular correlation analysis techniques, namely canonical correlation analysis, multivariate linear regression, and partial least squares, are reviewed and connected to performance measures in signal processing and communications, such as mean-squared estimation error, mutual information, and signal-to-noise ratio (SNR). For complex data, there are three types of correlation coefficients, which account for rotational, reflectional, and total (i.e., rotational and reflectional) dependencies between two random vectors. These three types are defined and analyzed for different correlation coefficients, and a numerical example is given. It is often required to compare two complex random vectors in a lower-dimensional subspace. For the large class of increasing, Schur-convex correlation coefficients, it is shown that the low-rank approximations of two random vectors maximizing a particular correlation coefficient are determined only by the constraints imposed on the correlation analysis technique. In this context, the correlation spread is defined as a normalized measure of how much of the overall correlation is contained in a low-dimensional subspace.}}, author = {{Schreier, Peter J.}}, journal = {{{IEEE} {T}rans.\ {S}ignal\ {P}rocess.}}, number = {{4}}, pages = {{1327–1336}}, title = {{{A Unifying Discussion of Correlation Analysis for Complex Random Vectors}}}, doi = {{10.1109/TSP.2007.909054}}, volume = {{56}}, year = {{2008}}, } @article{40864, abstract = {{We present a novel way of extending rotary-component and polarization analysis to nonstationary random signals. If a complex signal is resolved into counterclockwise and clockwise rotating phasors at one particular frequency only, it traces out an ellipse in the complex plane. Rotary-component analysis characterizes this ellipse in terms of its shape and orientation. Polarization analysis looks at the coherence between counterclockwise and clockwise rotating phasors and whether there is a preferred rotation direction of the ellipse (counterclockwise or clockwise). In the nonstationary case, we replace this ellipse with a time-dependent local ellipse that, at a given time instant, gives the best local approximation of the signal from a given frequency component. This local ellipse is then analyzed in terms of its shape, orientation, and degree of polarization. A time-frequency coherence measures how well the local ellipse approximates the signal. The ellipse parameters and the time-frequency coherence can be expressed in terms of the Rihaczek time-frequency distribution. Under coordinate rotation, the ellipse shape, the degree of polarization, and the time-frequency coherence are invariant, and the ellipse orientation is covariant. The methods presented in this paper provide an alternative to ellipse decompositions based on wavelet ridge analysis.}}, author = {{Schreier, Peter J.}}, journal = {{{IEEE} {T}rans.\ {S}ignal\ {P}rocess.}}, number = {{9}}, pages = {{4330–4339}}, title = {{{Polarization Ellipse Analysis of Nonstationary Random Signals}}}, doi = {{10.1109/TSP.2008.925961}}, volume = {{56}}, year = {{2008}}, } @inproceedings{40869, abstract = {{The coherence spectrum is a well-known measure of the linear statistical relationship between two time series. In this paper, we extend this concept to several processes and define the generalized magnitude squared coherence (GMSC) spectrum as a function of the largest eigenvalue of a matrix containing all the pairwise complex coherence spectra. The GMSC is bounded between zero and one, and attains its maximum when all the processes are perfectly correlated at a given frequency. Furthermore, three different GMSC spectrum estimators, extending those previously proposed for the MSC of two processes, are presented. Specifically, we compare the Welch method, the minimum variance distortionless response (MVDR) estimator and a new estimator based on canonical correlation analysis (CCA).}}, author = {{Ramírez, D. and Vía, J. and Santamaría, I.}}, booktitle = {{Proc.\ IEEE Int.\ Conf.\ Acoustics, Speech and Signal Process.}}, title = {{{A generalization of the magnitude squared coherence spectrum for more than two signals: definition, properties and estimation}}}, doi = {{10.1109/ICASSP.2008.4518473}}, year = {{2008}}, } @inproceedings{40863, abstract = {{This paper is concerned with coded multi-ary systems over linear channels. Based on a semi-analytical evolution technique, the impact of signaling schemes on the performance of low-cost iterative linear minimum-mean-square-error (LMMSE) detection is studied. It is shown that superposition coded modulation (SCM) maximizes the output signal-to-noise ratio (SNR) of LMMSE detectors. Consequently, SCM may potentially outperform other conventional signaling schemes when LMMSE detectors are used. Numerical examples are provided to verify the theoretical analysis.}}, author = {{Ping, Li and Tong, Jun and Yuan, Xiaojun and Guo, Qinghua}}, booktitle = {{5th\ Int.\ Symp.\ Turbo Codes & Rel.\ Top.}}, pages = {{192–197}}, title = {{{Performance analysis of multi-ary systems with iterative linear minimum-mean-square-error detection}}}, doi = {{10.1109/TURBOCODING.2008.4658696}}, year = {{2008}}, } @article{40862, author = {{Ramírez, D. and Santamaría, I. and Pérez, J. and Vía, J. and García-Naya, J. A. and Fernández-Caramés, T. M. and Pérez-Iglesias, H. and López, M. González and Castedo, L. and Torres-Royo, J. M.}}, journal = {{Wireless Comm. and Mobile Computing}}, number = {{9}}, pages = {{1149–1164}}, title = {{{A comparative study of STBC transmissions at 2.4 GHz over indoor channels using a $2 \times 2$ MIMO testbed}}}, doi = {{10.1002/wcm.558}}, volume = {{8}}, year = {{2008}}, } @inproceedings{40861, abstract = {{This paper studies orthogonal frequency-division multiplexing (OFDM) systems employing coded modulation. Clipping is applied to reduce the peak-to-average-power-ratio (PAPR) of the transmit signal. A soft compensation method is proposed to combat the clipping effect. It is shown that the proposed method can outperform conventional clipping effect mitigation methods. The impact of signaling schemes of the coded modulation on system performance is investigated. The average variance analysis and numerical results demonstrate that superposition coded modulation (SCM) together with the proposed detection technique provides a simple and efficient solution to clipped OFDM transmission.}}, author = {{Tong, Jun and Ping, Li}}, booktitle = {{Proc.\ IEEE Global Telecomm.\ Conf.}}, pages = {{1–5}}, title = {{{Iterative detection techniques for clipped OFDM systems}}}, doi = {{10.1109/GLOCOM.2008.ECP.225}}, year = {{2008}}, } @inproceedings{40871, abstract = {{A complex random vector is called improper (noncircular) if it is correlated with its complex conjugate. We consider measures for the degree of impropriety that are invariant under linear transformation. These measures are functions of the canonical correlations between the vector and its complex conjugate, which have been termed the circularity coefficients. However, we show that these circularity coefficients do not tell the whole story: Two random vectors with identical covariance matrix and identical circularity coefficients can still behave differently in second-order estimation and detection.}}, author = {{Schreier, Peter J.}}, booktitle = {{Proc.\ IEEE Int.\ Conf.\ Acoustics, Speech and Signal Process.}}, pages = {{3909–3912}}, title = {{{The degree of impropriety (noncircularity) of complex random vectors}}}, doi = {{10.1109/ICASSP.2008.4518508}}, year = {{2008}}, } @article{14927, author = {{Hundsdoerfer, Jochen and Kiesewetter, Dirk and Sureth-Sloane, Caren}}, issn = {{0044-2372}}, journal = {{Zeitschrift für Betriebswirtschaft}}, number = {{1}}, pages = {{61--139}}, title = {{{Forschungsergebnisse in der Betriebswirtschaftlichen Steuerlehre — eine Bestandsaufnahme}}}, doi = {{10.1007/s11573-008-0004-4}}, volume = {{78}}, year = {{2008}}, } @article{41277, author = {{Rill, Christoph and Bauer, Matthias and Bertagnolli, Helmut and Kickelbick, Guido}}, issn = {{0021-9797}}, journal = {{Journal of Colloid and Interface Science}}, keywords = {{Colloid and Surface Chemistry, Surfaces, Coatings and Films, Biomaterials, Electronic, Optical and Magnetic Materials}}, number = {{1}}, pages = {{179--186}}, publisher = {{Elsevier BV}}, title = {{{Microemulsion approach to neodymium, europium, and ytterbium oxide/hydroxide colloids—Effects of precursors and preparation parameters on particle size and crystallinity}}}, doi = {{10.1016/j.jcis.2008.05.008}}, volume = {{325}}, year = {{2008}}, } @article{41278, author = {{Akdogan, Yasar and Vogt, Christina and Bauer, Matthias and Bertagnolli, Helmut and Giurgiu, Liviu and Roduner, Emil}}, issn = {{1463-9076}}, journal = {{Physical Chemistry Chemical Physics}}, keywords = {{Physical and Theoretical Chemistry, General Physics and Astronomy}}, number = {{20}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Platinum species in the pores of NaX, NaY and NaA zeolites studied using EPR, XAS and FTIR spectroscopies}}}, doi = {{10.1039/b718932j}}, volume = {{10}}, year = {{2008}}, } @article{41279, author = {{Wu, Jin-Ming and Antonietti, Markus and Gross, Silvia and Bauer, Matthias and Smarsly, Bernd M.}}, issn = {{1439-4235}}, journal = {{ChemPhysChem}}, keywords = {{Physical and Theoretical Chemistry, Atomic and Molecular Physics, and Optics}}, number = {{5}}, pages = {{748--757}}, publisher = {{Wiley}}, title = {{{Ordered Mesoporous Thin Films of Rutile TiO2 Nanocrystals Mixed with Amorphous Ta2O5}}}, doi = {{10.1002/cphc.200700679}}, volume = {{9}}, year = {{2008}}, } @inproceedings{41474, author = {{Seifert, Andreas and Schaper, Niclas}}, booktitle = {{Tagung „Kompetenzdiagnose und Kompetenzentwicklung in der Lehrerbildung“ des CEVET und PLAZ}}, location = {{Paderborn}}, title = {{{Erste Ergebnisse zur Messung pädagogischer Kompetenz in der universitären Lehrerausbildung.}}}, year = {{2008}}, }