[{"publication":"Journal of Manufacturing and Materials Processing","abstract":[{"text":"<jats:p>The pressure fields generated by two simultaneous discharges have not been investigated on any notable scale for the electrohydraulic impulse forming method. In this study, the synchronicity of two discharges is ensured by the sequential connection of two wires mounted in two spark gaps in a common volume of liquid. The objective is to experimentally confirm the equilibrium of the energies evolved in two spark gaps by means of pressure measurements. In addition, multipoint membrane pressure gauges demonstrated the feasibility of easily recording detailed pressure maps. Based on the membrane deformation mechanism and material strengthening under static and impulse conditions, the processing procedure is further developed so as to achieve better accuracy in the determination of pressure field parameters. The practical equality of the pressure fields on the left and right halves of the flat-loaded area confirms the equality of energies evolved in the two spark gaps. The direct shock waves create zones with the most intensive loading. These results provide a basis for the development of new electrohydraulic technologies involving the application of two simultaneous discharges with equal energy and pressure parameters.</jats:p>","lang":"eng"}],"language":[{"iso":"eng"}],"keyword":["impulse","forming","electrohydraulic","discharge","wire","pressure gauge","pressure field"],"issue":"1","quality_controlled":"1","year":"2023","date_created":"2023-03-17T10:31:23Z","publisher":"MDPI AG","title":"Investigation of Pressure Fields Generated by Two Simultaneous Discharges in Liquid Initiated by Wires","type":"journal_article","status":"public","department":[{"_id":"156"}],"user_id":"82645","_id":"43045","article_number":"40","publication_identifier":{"issn":["2504-4494"]},"publication_status":"published","intvolume":"         7","citation":{"bibtex":"@article{Knyazyev_Holzmüller_Homberg_2023, title={Investigation of Pressure Fields Generated by Two Simultaneous Discharges in Liquid Initiated by Wires}, volume={7}, DOI={<a href=\"https://doi.org/10.3390/jmmp7010040\">10.3390/jmmp7010040</a>}, number={140}, journal={Journal of Manufacturing and Materials Processing}, publisher={MDPI AG}, author={Knyazyev, Mykhaylo and Holzmüller, Maik and Homberg, Werner}, year={2023} }","short":"M. Knyazyev, M. Holzmüller, W. Homberg, Journal of Manufacturing and Materials Processing 7 (2023).","mla":"Knyazyev, Mykhaylo, et al. “Investigation of Pressure Fields Generated by Two Simultaneous Discharges in Liquid Initiated by Wires.” <i>Journal of Manufacturing and Materials Processing</i>, vol. 7, no. 1, 40, MDPI AG, 2023, doi:<a href=\"https://doi.org/10.3390/jmmp7010040\">10.3390/jmmp7010040</a>.","apa":"Knyazyev, M., Holzmüller, M., &#38; Homberg, W. (2023). Investigation of Pressure Fields Generated by Two Simultaneous Discharges in Liquid Initiated by Wires. <i>Journal of Manufacturing and Materials Processing</i>, <i>7</i>(1), Article 40. <a href=\"https://doi.org/10.3390/jmmp7010040\">https://doi.org/10.3390/jmmp7010040</a>","ama":"Knyazyev M, Holzmüller M, Homberg W. Investigation of Pressure Fields Generated by Two Simultaneous Discharges in Liquid Initiated by Wires. <i>Journal of Manufacturing and Materials Processing</i>. 2023;7(1). doi:<a href=\"https://doi.org/10.3390/jmmp7010040\">10.3390/jmmp7010040</a>","chicago":"Knyazyev, Mykhaylo, Maik Holzmüller, and Werner Homberg. “Investigation of Pressure Fields Generated by Two Simultaneous Discharges in Liquid Initiated by Wires.” <i>Journal of Manufacturing and Materials Processing</i> 7, no. 1 (2023). <a href=\"https://doi.org/10.3390/jmmp7010040\">https://doi.org/10.3390/jmmp7010040</a>.","ieee":"M. Knyazyev, M. Holzmüller, and W. Homberg, “Investigation of Pressure Fields Generated by Two Simultaneous Discharges in Liquid Initiated by Wires,” <i>Journal of Manufacturing and Materials Processing</i>, vol. 7, no. 1, Art. no. 40, 2023, doi: <a href=\"https://doi.org/10.3390/jmmp7010040\">10.3390/jmmp7010040</a>."},"volume":7,"author":[{"first_name":"Mykhaylo","full_name":"Knyazyev, Mykhaylo","last_name":"Knyazyev"},{"last_name":"Holzmüller","full_name":"Holzmüller, Maik","id":"82645","first_name":"Maik"},{"last_name":"Homberg","id":"233","full_name":"Homberg, Werner","first_name":"Werner"}],"date_updated":"2023-05-02T11:40:35Z","doi":"10.3390/jmmp7010040"},{"language":[{"iso":"eng"}],"keyword":["ASR","AURORA5 database","automatic speech recognition","Bayesian inference","belief networks","CMLLR","computational complexity","constrained maximum likelihood linear regression","least mean squares methods","LMPSC computation","logarithmic Mel power spectrum","maximum likelihood estimation","Mel frequency cepstral coefficients","MFCC feature vectors","microphone signal","minimum mean square error estimation","model-based feature enhancement","regression analysis","reverberant speech recognition","reverberation","RIR energy","room impulse response","speech recognition","stochastic observation model","stochastic processes"],"publication":"IEEE Transactions on Audio, Speech, and Language Processing","abstract":[{"text":"In this paper, we present a new technique for automatic speech recognition (ASR) in reverberant environments. Our approach is aimed at the enhancement of the logarithmic Mel power spectrum, which is computed at an intermediate stage to obtain the widely used Mel frequency cepstral coefficients (MFCCs). Given the reverberant logarithmic Mel power spectral coefficients (LMPSCs), a minimum mean square error estimate of the clean LMPSCs is computed by carrying out Bayesian inference. We employ switching linear dynamical models as an a priori model for the dynamics of the clean LMPSCs. Further, we derive a stochastic observation model which relates the clean to the reverberant LMPSCs through a simplified model of the room impulse response (RIR). This model requires only two parameters, namely RIR energy and reverberation time, which can be estimated from the captured microphone signal. The performance of the proposed enhancement technique is studied on the AURORA5 database and compared to that of constrained maximum-likelihood linear regression (CMLLR). It is shown by experimental results that our approach significantly outperforms CMLLR and that up to 80\\% of the errors caused by the reverberation are recovered. In addition to the fact that the approach is compatible with the standard MFCC feature vectors, it leaves the ASR back-end unchanged. It is of moderate computational complexity and suitable for real time applications.","lang":"eng"}],"date_created":"2019-07-12T05:29:23Z","title":"Model-Based Feature Enhancement for Reverberant Speech Recognition","issue":"7","year":"2010","user_id":"44006","department":[{"_id":"54"}],"_id":"11846","type":"journal_article","status":"public","author":[{"first_name":"Alexander","full_name":"Krueger, Alexander","last_name":"Krueger"},{"first_name":"Reinhold","full_name":"Haeb-Umbach, Reinhold","id":"242","last_name":"Haeb-Umbach"}],"volume":18,"oa":"1","date_updated":"2022-01-06T06:51:11Z","main_file_link":[{"open_access":"1","url":"https://groups.uni-paderborn.de/nt/pubs/2010/KrHa10.pdf"}],"doi":"10.1109/TASL.2010.2049684","citation":{"ama":"Krueger A, Haeb-Umbach R. Model-Based Feature Enhancement for Reverberant Speech Recognition. <i>IEEE Transactions on Audio, Speech, and Language Processing</i>. 2010;18(7):1692-1707. doi:<a href=\"https://doi.org/10.1109/TASL.2010.2049684\">10.1109/TASL.2010.2049684</a>","chicago":"Krueger, Alexander, and Reinhold Haeb-Umbach. “Model-Based Feature Enhancement for Reverberant Speech Recognition.” <i>IEEE Transactions on Audio, Speech, and Language Processing</i> 18, no. 7 (2010): 1692–1707. <a href=\"https://doi.org/10.1109/TASL.2010.2049684\">https://doi.org/10.1109/TASL.2010.2049684</a>.","ieee":"A. Krueger and R. Haeb-Umbach, “Model-Based Feature Enhancement for Reverberant Speech Recognition,” <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, vol. 18, no. 7, pp. 1692–1707, 2010.","apa":"Krueger, A., &#38; Haeb-Umbach, R. (2010). Model-Based Feature Enhancement for Reverberant Speech Recognition. <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, <i>18</i>(7), 1692–1707. <a href=\"https://doi.org/10.1109/TASL.2010.2049684\">https://doi.org/10.1109/TASL.2010.2049684</a>","short":"A. Krueger, R. Haeb-Umbach, IEEE Transactions on Audio, Speech, and Language Processing 18 (2010) 1692–1707.","mla":"Krueger, Alexander, and Reinhold Haeb-Umbach. “Model-Based Feature Enhancement for Reverberant Speech Recognition.” <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, vol. 18, no. 7, 2010, pp. 1692–707, doi:<a href=\"https://doi.org/10.1109/TASL.2010.2049684\">10.1109/TASL.2010.2049684</a>.","bibtex":"@article{Krueger_Haeb-Umbach_2010, title={Model-Based Feature Enhancement for Reverberant Speech Recognition}, volume={18}, DOI={<a href=\"https://doi.org/10.1109/TASL.2010.2049684\">10.1109/TASL.2010.2049684</a>}, number={7}, journal={IEEE Transactions on Audio, Speech, and Language Processing}, author={Krueger, Alexander and Haeb-Umbach, Reinhold}, year={2010}, pages={1692–1707} }"},"intvolume":"        18","page":"1692-1707"},{"intvolume":"         3","page":"III-277-III-280","citation":{"chicago":"Haeb-Umbach, Reinhold, and Maik Bevermeier. “OFDM Channel Estimation Based on Combined Estimation in Time and Frequency Domain.” In <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007)</i>, 3:III-277-III–280, 2007. <a href=\"https://doi.org/10.1109/ICASSP.2007.366526\">https://doi.org/10.1109/ICASSP.2007.366526</a>.","ieee":"R. Haeb-Umbach and M. Bevermeier, “OFDM Channel Estimation Based on Combined Estimation in Time and Frequency Domain,” in <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007)</i>, 2007, vol. 3, pp. III-277-III–280.","ama":"Haeb-Umbach R, Bevermeier M. OFDM Channel Estimation Based on Combined Estimation in Time and Frequency Domain. In: <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007)</i>. Vol 3. ; 2007:III-277-III-280. doi:<a href=\"https://doi.org/10.1109/ICASSP.2007.366526\">10.1109/ICASSP.2007.366526</a>","bibtex":"@inproceedings{Haeb-Umbach_Bevermeier_2007, title={OFDM Channel Estimation Based on Combined Estimation in Time and Frequency Domain}, volume={3}, DOI={<a href=\"https://doi.org/10.1109/ICASSP.2007.366526\">10.1109/ICASSP.2007.366526</a>}, booktitle={IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007)}, author={Haeb-Umbach, Reinhold and Bevermeier, Maik}, year={2007}, pages={III-277-III–280} }","mla":"Haeb-Umbach, Reinhold, and Maik Bevermeier. “OFDM Channel Estimation Based on Combined Estimation in Time and Frequency Domain.” <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007)</i>, vol. 3, 2007, pp. III-277-III–280, doi:<a href=\"https://doi.org/10.1109/ICASSP.2007.366526\">10.1109/ICASSP.2007.366526</a>.","short":"R. Haeb-Umbach, M. Bevermeier, in: IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007), 2007, pp. III-277-III–280.","apa":"Haeb-Umbach, R., &#38; Bevermeier, M. (2007). OFDM Channel Estimation Based on Combined Estimation in Time and Frequency Domain. In <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007)</i> (Vol. 3, pp. III-277-III–280). <a href=\"https://doi.org/10.1109/ICASSP.2007.366526\">https://doi.org/10.1109/ICASSP.2007.366526</a>"},"year":"2007","doi":"10.1109/ICASSP.2007.366526","main_file_link":[{"open_access":"1","url":"https://groups.uni-paderborn.de/nt/pubs/2007/HaBe07.pdf"}],"title":"OFDM Channel Estimation Based on Combined Estimation in Time and Frequency Domain","volume":3,"author":[{"first_name":"Reinhold","full_name":"Haeb-Umbach, Reinhold","id":"242","last_name":"Haeb-Umbach"},{"first_name":"Maik","last_name":"Bevermeier","full_name":"Bevermeier, Maik"}],"date_created":"2019-07-12T05:28:13Z","oa":"1","date_updated":"2022-01-06T06:51:08Z","status":"public","abstract":[{"lang":"eng","text":"In this paper we present a novel channel impulse response estimation technique for block-oriented OFDM transmission based on combining estimators: the estimates provided by a Kalman filter operating in the time domain and a Wiener filter in the frequency domain are optimally combined by taking into account their estimated error covariances. The resulting estimator turns out to be identical to the MAP estimator of correlated jointly Gaussian mean vectors. Different variants of the proposed scheme are experimentally investigated in an EEEE 802.11a-like system setup. They compare favourably with known approaches from the literature resulting in reduced mean square estimation error and bit error rate. Further, robustness and complexity issues are discussed"}],"publication":"IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2007)","type":"conference","language":[{"iso":"eng"}],"keyword":["bit error rate","block-oriented OFDM transmission","channel estimation","channel impulse response estimation","combining estimators","error statistics","frequency domain estimation","Gaussian mean vectors","Gaussian processes","Kalman filter","Kalman filters","MAP estimator","maximum likelihood estimation","OFDM channel estimation","OFDM modulation","time domain estimation","time-frequency analysis","Wiener filter","Wiener filters"],"department":[{"_id":"54"}],"user_id":"44006","_id":"11785"},{"_id":"11869","user_id":"44006","department":[{"_id":"54"}],"keyword":["acoustic echo cancellation algorithms","adverse environmental conditions","automatic speech recognition","cepstral analysis","cepstral features","cepstral mean normalization","command word task","delta-delta features","delta features","echo suppression","error rate reductions","feature vector components","FIR filters","LDA derived cepstral trajectory filters","linear discriminant analysis","long-range feature filters","phone accuracy","real-life room impulse responses","reverberant data","spectral parameters","speech recognition","standard TIMIT phone recognition task"],"language":[{"iso":"eng"}],"type":"conference","publication":"IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000)","abstract":[{"text":"Amongst several data driven approaches for designing filters for the time sequence of spectral parameters, the linear discriminant analysis (LDA) based method has been proposed for automatic speech recognition. Here we apply LDA-based filter design to cepstral features, which better match the inherent assumption of this method that feature vector components are uncorrelated. Extensive recognition experiments have been conducted both on the standard TIMIT phone recognition task and on a proprietary 130-words command word task under various adverse environmental conditions, including reverberant data with real-life room impulse responses and data processed by acoustic echo cancellation algorithms. Significant error rate reductions have been achieved when applying the novel long-range feature filters compared to standard approaches employing cepstral mean normalization and delta and delta-delta features, in particular when facing acoustic echo cancellation scenarios and room reverberation. For example, the phone accuracy on reverberated TIMIT data could be increased from 50.7\\% to 56.0\\%","lang":"eng"}],"status":"public","date_updated":"2022-01-06T06:51:11Z","oa":"1","date_created":"2019-07-12T05:29:50Z","author":[{"first_name":"M.","full_name":"Lieb, M.","last_name":"Lieb"},{"id":"242","full_name":"Haeb-Umbach, Reinhold","last_name":"Haeb-Umbach","first_name":"Reinhold"}],"volume":2,"title":"LDA derived cepstral trajectory filters in adverse environmental conditions","main_file_link":[{"open_access":"1","url":"https://groups.uni-paderborn.de/nt/pubs/2000/LiHa00.pdf"}],"doi":"10.1109/ICASSP.2000.859157","year":"2000","citation":{"bibtex":"@inproceedings{Lieb_Haeb-Umbach_2000, title={LDA derived cepstral trajectory filters in adverse environmental conditions}, volume={2}, DOI={<a href=\"https://doi.org/10.1109/ICASSP.2000.859157\">10.1109/ICASSP.2000.859157</a>}, booktitle={IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000)}, author={Lieb, M. and Haeb-Umbach, Reinhold}, year={2000}, pages={II1105-II1108 vol.2} }","short":"M. Lieb, R. Haeb-Umbach, in: IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000), 2000, pp. II1105-II1108 vol.2.","mla":"Lieb, M., and Reinhold Haeb-Umbach. “LDA Derived Cepstral Trajectory Filters in Adverse Environmental Conditions.” <i>IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000)</i>, vol. 2, 2000, pp. II1105-II1108 vol.2, doi:<a href=\"https://doi.org/10.1109/ICASSP.2000.859157\">10.1109/ICASSP.2000.859157</a>.","apa":"Lieb, M., &#38; Haeb-Umbach, R. (2000). LDA derived cepstral trajectory filters in adverse environmental conditions. In <i>IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000)</i> (Vol. 2, pp. II1105-II1108 vol.2). <a href=\"https://doi.org/10.1109/ICASSP.2000.859157\">https://doi.org/10.1109/ICASSP.2000.859157</a>","ieee":"M. Lieb and R. Haeb-Umbach, “LDA derived cepstral trajectory filters in adverse environmental conditions,” in <i>IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000)</i>, 2000, vol. 2, pp. II1105-II1108 vol.2.","chicago":"Lieb, M., and Reinhold Haeb-Umbach. “LDA Derived Cepstral Trajectory Filters in Adverse Environmental Conditions.” In <i>IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000)</i>, 2:II1105-II1108 vol.2, 2000. <a href=\"https://doi.org/10.1109/ICASSP.2000.859157\">https://doi.org/10.1109/ICASSP.2000.859157</a>.","ama":"Lieb M, Haeb-Umbach R. LDA derived cepstral trajectory filters in adverse environmental conditions. In: <i>IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2000)</i>. Vol 2. ; 2000:II1105-II1108 vol.2. doi:<a href=\"https://doi.org/10.1109/ICASSP.2000.859157\">10.1109/ICASSP.2000.859157</a>"},"page":"II1105-II1108 vol.2","intvolume":"         2"}]