@article{18632, abstract = {{We present measurements of the effective electron mass in biaxial tensile strained silicon on insulator (SSOI) material with 1.2 GPa stress and in unstrained SOI. Hall-bar metal oxide semiconductor field effect transistors on 60 nm SSOI and SOI were fabricated and Shubnikov–de Haas oscillations in the temperature range of T=0.4–4 K for magnetic fields of B=0–10 T were measured. The effective electron mass in SSOI and SOI samples was determined as mt=(0.20±0.01)m0. This result is in excellent agreement with first-principles calculations of the effective electron mass in the presence of strain.}}, author = {{Feste, Sebastian F. and Schäpers, Thomas and Buca, Dan and Zhao, Qing Tai and Knoch, Joachim and Bouhassoune, Mohammed and Schindlmayr, Arno and Mantl, Siegfried}}, issn = {{1077-3118}}, journal = {{Applied Physics Letters}}, number = {{18}}, publisher = {{American Institute of Physics}}, title = {{{Measurement of effective electron mass in biaxial tensile strained silicon on insulator}}}, doi = {{10.1063/1.3254330}}, volume = {{95}}, year = {{2009}}, } @inproceedings{18634, abstract = {{A computational method to obtain optical conductivities from first principles is presented. It exploits a relation between the conductivity and the complex dielectric function, which is constructed from the full electronic band structure within the random-phase approximation. In contrast to the Drude model, no empirical parameters are used. As interband transitions as well as local-field effects are properly included, the calculated spectra are valid over a wide frequency range. As an illustration I present quantitative results for selected simple metals, noble metals, and ferromagnetic transition metals. The implementation is based on the full-potential linearized augmented-plane-wave method.}}, author = {{Schindlmayr, Arno}}, booktitle = {{Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop}}, editor = {{Chigrin, Dmitry N.}}, isbn = {{978-0-7354-0715-2}}, issn = {{1551-7616}}, location = {{Bad Honnef}}, number = {{1}}, pages = {{157--159}}, publisher = {{American Institute of Physics}}, title = {{{Optical conductivity of metals from first principles}}}, doi = {{10.1063/1.3253897}}, volume = {{1176}}, year = {{2009}}, } @techreport{2737, author = {{Gries, Thomas and Redlin, Margarete}}, isbn = {{978-92-9230-116-3}}, pages = {{37}}, publisher = {{WIDER Research Papers, United Nations University (UNU)}}, title = {{{International integration and regional development in China }}}, volume = {{2008.66}}, year = {{2008}}, } @inproceedings{1940, author = {{Mense, Mario and Scheideler, Christian}}, booktitle = {{Proceedings of the Nineteenth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2008, San Francisco, California, USA, January 20-22, 2008}}, pages = {{1135----1144}}, publisher = {{SIAM}}, title = {{{SPREAD: an adaptive scheme for redundant and fair storage in dynamic heterogeneous storage systems}}}, year = {{2008}}, } @article{4256, abstract = {{We present phase-resolved pulse propagation measurements that allow us to fully describe the transition between several light–matter interaction regimes. The complete range from linear excitation to the breakdown of the photonic bandgap on to self-induced transmission and self-phase modulation is studied on a high-quality multiple-quantum-well Bragg structure. An improved fast-scanning cross-correlation frequency-resolved optical gating setup is applied to retrieve the pulse phase with an excellent signal-tonoise ratio. Calculations using the semiconductor Maxwell–Bloch equations show qualitative agreement with the experimental findings. }}, author = {{zu Siederdissen, Tilman Höner and Nielsen, Nils C. and Kuhl, Jürgen and Schaarschmidt, Martin and Förstner, Jens and Knorr, Andreas and Khitrova, Galina and Gibbs, Hyatt M. and Koch, Stephan W. and Giessen, Harald}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, keywords = {{tet_topic_polariton, tet_topic_qw}}, number = {{11}}, publisher = {{The Optical Society}}, title = {{{Transition between different coherent light–matter interaction regimes analyzed by phase-resolved pulse propagation}}}, doi = {{10.1364/ol.30.001384}}, volume = {{30}}, year = {{2008}}, } @article{5648, author = {{Schryen, Guido}}, journal = {{Linux Technical Review}}, number = {{7}}, publisher = {{Linux New Media AG}}, title = {{{Effektivität und Effizienz von Anti-Spam-Maßnahmen}}}, year = {{2008}}, } @inproceedings{5649, abstract = {{The Estonian parliamentary election in 2007 is regarded as a success story of large-scale Internet elections. I use this election in a single case study on practical security to show that low quality of security and its management does not necessarily prevent large-scale Internet elections from being conducted. I also provide research propositions with regard to future challenges for large-scale Internet elections.}}, author = {{Schryen, Guido}}, booktitle = {{7th Workshop on e-Business (WEB 2008, AIS Special Interest Group on E-Business)}}, keywords = {{Internet voting, large-scale election, Estonian parliamen- tary election, security, security management}}, title = {{{Practical Security of Large-scale Elections: An Exploratory Case Study of Internet Voting in Estonia}}}, year = {{2008}}, } @article{1169, abstract = {{The standard approach of job search engines disregards the structural aspect of job announcements in the Web. Bag-of-words indexing leads to a high amount of noise. In this paper we describe a method that uses local grammars to transform unstructured Web pages into structured forms. Evaluation experiments show high efficiency of information access to the generated documents.}}, author = {{Bsiri, Sandra and Geierhos, Michaela and Ringlstetter, Christoph}}, issn = {{1870-4069}}, journal = {{Research in Computing Science}}, pages = {{201--212}}, publisher = {{National Polytechnic Institute of Mexico}}, title = {{{Structuring Job Search via Local Grammars}}}, volume = {{33}}, year = {{2008}}, } @article{11776, abstract = {{The term uncertainty decoding has been phrased for a class of robustness enhancing algorithms in automatic speech recognition that replace point estimates and plug-in rules by posterior densities and optimal decision rules. While uncertainty can be incorporated in the model domain, in the feature domain, or even in both, we concentrate here on feature domain approaches as they tend to be computationally less demanding. We derive optimal decision rules in the presence of uncertain observations and discuss simplifications which result in computationally efficient realizations. The usefulness of the presented statistical framework is then exemplified for two types of realworld problems: The first is improving the robustness of speech recognition towards incomplete or corrupted feature vectors due to a lossy communication link between the speech capturing front end and the backend recognition engine. And the second is the well-known and extensively studied issue of improving the robustness of the recognizer towards environmental noise.}}, author = {{Haeb-Umbach, Reinhold}}, journal = {{2008 ITG Conference on Voice Communication (SprachKommunikation)}}, pages = {{1--7}}, title = {{{Uncertainty Decoding in Automatic Speech Recognition}}}, year = {{2008}}, } @inbook{11789, abstract = {{In distributed and network speech recognition the actual recognition task is not carried out on the user{\rq}s terminal but rather on a remote server in the network. While there are good reasons for doing so, a disadvantage of this client-server architecture is clearly that the communication medium may introduce errors, which then impairs speech recognition accuracy. Even sophisticated channel coding cannot completely prevent the occurrence of residual bit errors in the case of temporarily adverse channel conditions, and in packet-oriented transmission packets of data may arrive too late for the given real-time constraints and have to be declared lost. The goal of error concealment is to reduce the detrimental effect that such errors may induce on the recipient of the transmitted speech signal by exploiting residual redundancy in the bit stream at the source coder output. In classical speech transmission a human is the recipient, and erroneous data are reconstructed so as to reduce the subjectively annoying effect of corrupted bits or lost packets. Here, however, a statistical classifier is at the receiving end, which can benefit from knowledge about the quality of the reconstruction. In this book chapter we show how the classical Bayesian decision rule needs to be modified to account for uncertain features, and illustrate how the required feature posterior density can be estimated in the case of distributed speech recognition. Some other techniques for error concealment can be related to this approach. Experimental results are given for both a small and a medium vocabulary recognition task and both for a channel exhibiting bit errors and a packet erasure channel.}}, author = {{Haeb-Umbach, Reinhold and Ion, Valentin}}, booktitle = {{Automatic Speech Recognition on Mobile Devices and over Communication Networks}}, editor = {{Lindenberg, Borge and Tan, Zheng-Hua}}, pages = {{187--210}}, publisher = {{Springer}}, title = {{{Error Concealement}}}, volume = {{Advances in Computer Vision and Pattern Recognition}}, year = {{2008}}, } @article{11820, abstract = {{In this paper, we derive an uncertainty decoding rule for automatic speech recognition (ASR), which accounts for both corrupted observations and inter-frame correlation. The conditional independence assumption, prevalent in hidden Markov model-based ASR, is relaxed to obtain a clean speech posterior that is conditioned on the complete observed feature vector sequence. This is a more informative posterior than one conditioned only on the current observation. The novel decoding is used to obtain a transmission-error robust remote ASR system, where the speech capturing unit is connected to the decoder via an error-prone communication network. We show how the clean speech posterior can be computed for communication links being characterized by either bit errors or packet loss. Recognition results are presented for both distributed and network speech recognition, where in the latter case common voice-over-IP codecs are employed.}}, author = {{Ion, Valentin and Haeb-Umbach, Reinhold}}, journal = {{IEEE Transactions on Audio, Speech, and Language Processing}}, keywords = {{automatic speech recognition, bit errors, codecs, communication links, corrupted observations, decoding, distributed speech recognition, error-prone communication network, feature vector sequence, hidden Markov model-based ASR, hidden Markov models, inter-frame correlation, Internet telephony, network speech recognition, packet loss, speech posterior, speech recognition, transmission error robust speech recognition, uncertainty decoding, voice-over-IP codecs}}, number = {{5}}, pages = {{1047--1060}}, title = {{{A Novel Uncertainty Decoding Rule With Applications to Transmission Error Robust Speech Recognition}}}, doi = {{10.1109/TASL.2008.925879}}, volume = {{16}}, year = {{2008}}, } @article{11821, abstract = {{This paper addresses the robustness of automatic speech recognition to environmental noise. In order to account for reliability of the clean feature estimate we employ the feature posterior density conditioned on observed noisy features to perform uncertainty decoding. We investigate two approaches to estimate the posterior using a discrete feature space, first conditioning only on the current observation, and second on the whole feature sequence of an utterance. Experiments with Aurora 2 showed that the latter provides slightly better performance, as it allows for exploiting the temporal correlations between consecutive features.}}, author = {{Ion, Valentin and Haeb-Umbach, Reinhold}}, journal = {{2008 ITG Conference on Voice Communication (SprachKommunikation)}}, pages = {{1--4}}, title = {{{Investigations into Uncertainty Decoding Employing a Discrete Feature Space for Noise Robust Automatic Speech Recognition}}}, year = {{2008}}, } @inproceedings{11851, abstract = {{In diesem Beitrag werden zwei neuartige akustische Strahlformungsalgorithmen fuer einen Einsatz im KFZ diskutiert. In beiden Verfahren ist fuer jede Frequenzkomponente der Eigenvektor zum groessten Eigenwert eines verallgemeinerten Eigenwertproblems zu bestimmen: bei der einen Varianate stellen die Filterkoeffizienten gerade obigen Eigenvektor dar. Sprachverzerrungen werden mit einem einkanaligen Nachfilter kompensiert. In der anderen Variante, welche die Struktur eines ''Generalized Sidelobe Cancellers'' (GSC) hat, basiert die Blockiermatrix auf obiger Eigenvektorzerlegung.}}, author = {{Krueger, Alexander and Warsitz, Ernst and Haeb-Umbach, Reinhold}}, booktitle = {{34. Deutsche Jahrestagung fuer Akustik (DAGA 2008)}}, title = {{{Blinde Akustische Strahlformung fuer Anwendungen im KFZ}}}, year = {{2008}}, } @article{11914, abstract = {{This paper considers the convolutive blind source separation of speech sources in the presence of spatially correlated noise. We introduce a method for estimating the scaled mixing matrix from the sources to the microphones even if coherent noise is present. This is achieved by combining time-frequency sparseness with the generalized eigenvalue decomposition of the power spectral density matrix (PSD) of the noisy speech and noise-only microphone signals. Separation is performed by spatial filtering with coefficients constructed by Gram-Schmidt orthogonalization which places spatial nulls at the interferer{^A}?`s direction. Experimental results show that our approach is capable of separating 2 sources in a reverberant environment (RT60=0ms..500ms) degraded by significant directional noise.}}, author = {{Tran Vu, Dang Hai and Haeb-Umbach, Reinhold}}, journal = {{2008 ITG Conference on Voice Communication (SprachKommunikation)}}, pages = {{1--4}}, title = {{{Blind Speech Separation in Presence of Correlated Noise with Generalized Eigenvector Beamforming}}}, year = {{2008}}, } @inproceedings{11915, abstract = {{This Paper deals with a new Technique for multi-channel separation of speech signals from convolutive mixtures under coherent noise. We demonstrate how the scaled transfer functions from the sources to the microphones can be estimated even in the presence of stationary coherent noise. The key to this are generalized eigenvalue decompositions of the power spectral density (PSD) matrices of the noisy speech and noise-only microphone signals with a controlled estimation of these matrices exploiting time-frequency sparseness of the speech sources. Separation is further improved by subsequent Gram-Schmidt orthogonalization which places spatial nulls at the interferers{\rq} directions, while noise reduction is improved by employing a novel blocking matrix and adaptive interference canceller in a Generalized Sidelobe Canceller (GSC)-like structure. We report promising experimental results for 2 speech sources with significant coherent noise in reverberant environments (RT60=0oms..500ms).}}, author = {{Tran Vu, Dang Hai and Krueger, Alexander and Haeb-Umbach, Reinhold}}, booktitle = {{International Workshop on Acoustic Echo and Noise Control (IWAENC 2008)}}, title = {{{Generalized Eigenvector Blind Speech Separation Under Coherent Noise In A GSC Configuration}}}, year = {{2008}}, } @inproceedings{11935, abstract = {{The generalized sidelobe canceller by Griffith and Jim is a robust beamforming method to enhance a desired (speech) signal in the presence of stationary noise. Its performance depends to a high degree on the construction of the blocking matrix which produces noise reference signals for the subsequent adaptive interference canceller. Especially in reverberated environments the beamformer may suffer from signal leakage and reduced noise suppression. In this paper a new blocking matrix is proposed. It is based on a generalized eigenvalue problem whose solution provides an indirect estimation of the transfer functions from the source to the sensors. The quality of the new generalized eigenvector blocking matrix is studied in simulated rooms with different reverberation times and is compared to alternatives proposed in the literature.}}, author = {{Warsitz, Ernst and Krueger, Alexander and Haeb-Umbach, Reinhold}}, booktitle = {{IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)}}, keywords = {{adaptive interference canceller, adaptive signal processing, array signal processing, beamforming method, eigenvalues and eigenfunctions, generalized eigenvector blocking matrix, generalized sidelobe canceller, interference suppression, matrix algebra, noise suppression, speech enhancement, transfer function estimation, transfer functions}}, pages = {{73--76}}, title = {{{Speech enhancement with a new generalized eigenvector blocking matrix for application in a generalized sidelobe canceller}}}, doi = {{10.1109/ICASSP.2008.4517549}}, year = {{2008}}, } @inproceedings{11939, abstract = {{In this paper a switching linear dynamical model (SLDM) approach for speech feature enhancement is improved by employing more accurate models for the dynamics of speech and noise. The model of the clean speech feature trajectory is improved by augmenting the state vector to capture information derived from the delta features. Further a hidden noise state variable is introduced to obtain a more elaborated model for the noise dynamics. Approximate Bayesian inference in the SLDM is carried out by a bank of extended Kalman filters, whose outputs are combined according to the a posteriori probability of the individual state models. Experimental results on the AURORA2 database show improved recognition accuracy.}}, author = {{Windmann, Stefan and Haeb-Umbach, Reinhold}}, booktitle = {{IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)}}, keywords = {{a posteriori probability, AURORA2 database, Bayesian inference, Bayes methods, channel bank filters, extended Kalman filter banks, hidden noise state variable, Kalman filters, noise dynamics, speech enhancement, speech feature enhancement, speech feature trajectory, switching linear dynamical model approach}}, pages = {{4409--4412}}, title = {{{Modeling the dynamics of speech and noise for speech feature enhancement in ASR}}}, doi = {{10.1109/ICASSP.2008.4518633}}, year = {{2008}}, } @article{11940, abstract = {{In this paper, the noise estimation for model-based speech feature enhancement in automatic speech recognition (ASR) is investigated. Beside a stationary noise prior, three linear state space models for the (cepstral) noise process are considered. We have derived novel EM algorithms for the estimation of the noise model parameters: A blockwise EM algorithm is applied on noise-only input data. It is supposed to be used during the offline training mode of the recognizer. Further a sequential online EM algorithm is employed to adapt the observation variance in recognition mode which works as well under the asumption of a stationary noise prior and a linear state model for the noise. Experiments on the AURORA4 database lead to improved recognition results with the new state model compared to the assumption of stationary noise.}}, author = {{Windmann, Stefan and Haeb-Umbach, Reinhold}}, journal = {{2008 ITG Conference on Voice Communication (SprachKommunikation)}}, pages = {{1--4}}, title = {{{A novel approach to noise estimation in model-based speech feature enhancement}}}, year = {{2008}}, } @article{11944, abstract = {{In this paper, a novel segmental Hidden Markov Model (HMM) is proposed. The model is based on a modified emission density where additional statistical dependencies between subsequent frames of the speech signal are considered. In the following we derive an effective search strategy for the modified statistical model. Further an approach to parameter reduction is introduced. Experiments were carried out on the AURORA2 database where consistent im}}, author = {{Windmann, Stefan and Haeb-Umbach, Reinhold and Leutnant, Volker}}, journal = {{2008 ITG Conference on Voice Communication (SprachKommunikation)}}, pages = {{1--4}}, title = {{{A segmental HMM based on a modified emission probability}}}, year = {{2008}}, } @article{32518, abstract = {{This study investigates age-related changes and dyadic-specific differences in adult child–parent relationships. Using an individuation framework, two German samples of 224 and 105 participants aged between 21 and 47 years were administered the Network of Relationships Inventory, the Emotional Autonomy Scale and the Authority Reciprocity Questionnaire. Factor analyses resulted in a measurement model valid for adult children, their mothers and fathers. The model includes connectedness (with emotional and cognitive aspects) as well as individuality (assessed as power symmetry). Connectedness decreased with age. Symmetry in father–child relationships increased over time, while mother–child relationships were perceived to be symmetrical by early adulthood. Child–mother relationships were more connected than child–father relationships. Sons described themselves as more powerful than did daughters.}}, author = {{Buhl, Heike M.}}, journal = {{International Journal of Behavioral Development}}, keywords = {{adult child–parent relationships, adulthood, connectedness, Germany, individuation, symmetry}}, number = {{5}}, pages = {{381 -- 389}}, title = {{{Development of a model describing individuated adult child-parent relationships}}}, volume = {{32}}, year = {{2008}}, }