[{"quality_controlled":"1","citation":{"mla":"Rüther, Torben Norbert, et al. “Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional Measurements.” <i>Powders</i>, vol. 4, no. 2, 11, MDPI AG, 2025, doi:<a href=\"https://doi.org/10.3390/powders4020011\">10.3390/powders4020011</a>.","apa":"Rüther, T. N., Gröne, S., Dechert, C., &#38; Schmid, H.-J. (2025). Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional Measurements. <i>Powders</i>, <i>4</i>(2), Article 11. <a href=\"https://doi.org/10.3390/powders4020011\">https://doi.org/10.3390/powders4020011</a>","ieee":"T. N. Rüther, S. Gröne, C. Dechert, and H.-J. Schmid, “Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional Measurements,” <i>Powders</i>, vol. 4, no. 2, Art. no. 11, 2025, doi: <a href=\"https://doi.org/10.3390/powders4020011\">10.3390/powders4020011</a>.","short":"T.N. Rüther, S. Gröne, C. Dechert, H.-J. Schmid, Powders 4 (2025).","ama":"Rüther TN, Gröne S, Dechert C, Schmid H-J. Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional Measurements. <i>Powders</i>. 2025;4(2). doi:<a href=\"https://doi.org/10.3390/powders4020011\">10.3390/powders4020011</a>","chicago":"Rüther, Torben Norbert, Sebastian Gröne, Christopher Dechert, and Hans-Joachim Schmid. “Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional Measurements.” <i>Powders</i> 4, no. 2 (2025). <a href=\"https://doi.org/10.3390/powders4020011\">https://doi.org/10.3390/powders4020011</a>.","bibtex":"@article{Rüther_Gröne_Dechert_Schmid_2025, title={Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional Measurements}, volume={4}, DOI={<a href=\"https://doi.org/10.3390/powders4020011\">10.3390/powders4020011</a>}, number={211}, journal={Powders}, publisher={MDPI AG}, author={Rüther, Torben Norbert and Gröne, Sebastian and Dechert, Christopher and Schmid, Hans-Joachim}, year={2025} }"},"status":"public","user_id":"464","volume":4,"publisher":"MDPI AG","_id":"61014","funded_apc":"1","abstract":[{"lang":"eng","text":"<jats:p>To obtain a more comprehensive understanding of the specific properties of complex-shaped technical aerosols—such as partially sintered aggregates formed in combustion processes or structured particles resulting from complex synthesis processes—it is essential to measure more than a single equivalent size. This study examines a novel method for determining a two-dimensional distribution of two distinct particle properties within the size range from 50nm to 1000nm: the Centrifugal Differential Mobility Analyzer (CDMA). The CDMA enables the simultaneous measurement of both mobility and Stokes equivalent diameters, providing a detailed two-dimensional particle property distribution. This, in turn, allows for the extraction of shape-related information, which is essential for characterizing particles in terms of their chemical composition, reactivity, and other physicochemical properties. This paper presents a detailed evaluation of a first CDMA prototype. First, CFD simulations of the flow field within the classifier are presented in order to assess and understand non-idealities arising from the exact geometry. Subsequently, the transfer function is evaluated by particle trajectory calculations based on the simulated flow field. It can be demonstrated that the simulated transfer functions agree quite well with transfer functions derived from streamlines of an ideal flow field, indicating that the non-idealities in the classifying region are almost negligible in their effect on the classification result. An experimental determination of the transfer function shows additional effects not covered by the previous simulations, like broadening by diffusion and losses due to diffusion and precipitation within the in- and outlet of the classifier. Finally, the determined transfer functions are used to determine the full two-dimensional distribution with regard to the mobility and Stokes equivalent diameter of real aerosols, like spherical particles and aggregates at different sintering stages, respectively.</jats:p>"}],"issue":"2","publication":"Powders","keyword":["centrifugal differential mobility analysis","2D-measurement","particle characterization","moving reference frame CFD-simulation","transfer function"],"type":"journal_article","date_created":"2025-08-25T16:10:45Z","date_updated":"2025-08-25T16:15:41Z","publication_status":"published","intvolume":"         4","article_type":"original","title":"Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional Measurements","year":"2025","publication_identifier":{"issn":["2674-0516"]},"author":[{"full_name":"Rüther, Torben Norbert","first_name":"Torben Norbert","last_name":"Rüther"},{"full_name":"Gröne, Sebastian","last_name":"Gröne","first_name":"Sebastian"},{"last_name":"Dechert","first_name":"Christopher","full_name":"Dechert, Christopher"},{"first_name":"Hans-Joachim","last_name":"Schmid","orcid":"000-0001-8590-1921","full_name":"Schmid, Hans-Joachim","id":"464"}],"doi":"10.3390/powders4020011","article_number":"11","language":[{"iso":"eng"}]},{"doi":"10.1109/TASL.2010.2047324","main_file_link":[{"url":"https://groups.uni-paderborn.de/nt/pubs/2011/KrWaHa11.pdf","open_access":"1"}],"language":[{"iso":"eng"}],"date_updated":"2022-01-06T06:51:11Z","intvolume":"        19","title":"Speech Enhancement With a GSC-Like Structure Employing Eigenvector-Based Transfer Function Ratios Estimation","year":"2011","author":[{"full_name":"Krueger, Alexander","last_name":"Krueger","first_name":"Alexander"},{"full_name":"Warsitz, Ernst","first_name":"Ernst","last_name":"Warsitz"},{"id":"242","first_name":"Reinhold","last_name":"Haeb-Umbach","full_name":"Haeb-Umbach, Reinhold"}],"type":"journal_article","keyword":["acoustical transfer function ratio","adaptive eigenvector tracking","array signal processing","beamformer design","blocking matrix","eigenvalues and eigenfunctions","eigenvector-based transfer function ratios estimation","generalized sidelobe canceler","interference reduction","iterative methods","power iteration method","reduced speech distortions","reverberant enclosure","reverberation","speech enhancement","stationary noise"],"department":[{"_id":"54"}],"date_created":"2019-07-12T05:29:28Z","abstract":[{"lang":"eng","text":"In this paper, we present a novel blocking matrix and fixed beamformer design for a generalized sidelobe canceler for speech enhancement in a reverberant enclosure. They are based on a new method for estimating the acoustical transfer function ratios in the presence of stationary noise. The estimation method relies on solving a generalized eigenvalue problem in each frequency bin. An adaptive eigenvector tracking utilizing the power iteration method is employed and shown to achieve a high convergence speed. Simulation results demonstrate that the proposed beamformer leads to better noise and interference reduction and reduced speech distortions compared to other blocking matrix designs from the literature."}],"issue":"1","publication":"IEEE Transactions on Audio, Speech, and Language Processing","user_id":"44006","volume":19,"page":"206-219","_id":"11850","status":"public","oa":"1","citation":{"mla":"Krueger, Alexander, et al. “Speech Enhancement With a GSC-Like Structure Employing Eigenvector-Based Transfer Function Ratios Estimation.” <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, vol. 19, no. 1, 2011, pp. 206–19, doi:<a href=\"https://doi.org/10.1109/TASL.2010.2047324\">10.1109/TASL.2010.2047324</a>.","ama":"Krueger A, Warsitz E, Haeb-Umbach R. Speech Enhancement With a GSC-Like Structure Employing Eigenvector-Based Transfer Function Ratios Estimation. <i>IEEE Transactions on Audio, Speech, and Language Processing</i>. 2011;19(1):206-219. doi:<a href=\"https://doi.org/10.1109/TASL.2010.2047324\">10.1109/TASL.2010.2047324</a>","bibtex":"@article{Krueger_Warsitz_Haeb-Umbach_2011, title={Speech Enhancement With a GSC-Like Structure Employing Eigenvector-Based Transfer Function Ratios Estimation}, volume={19}, DOI={<a href=\"https://doi.org/10.1109/TASL.2010.2047324\">10.1109/TASL.2010.2047324</a>}, number={1}, journal={IEEE Transactions on Audio, Speech, and Language Processing}, author={Krueger, Alexander and Warsitz, Ernst and Haeb-Umbach, Reinhold}, year={2011}, pages={206–219} }","apa":"Krueger, A., Warsitz, E., &#38; Haeb-Umbach, R. (2011). Speech Enhancement With a GSC-Like Structure Employing Eigenvector-Based Transfer Function Ratios Estimation. <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, <i>19</i>(1), 206–219. <a href=\"https://doi.org/10.1109/TASL.2010.2047324\">https://doi.org/10.1109/TASL.2010.2047324</a>","ieee":"A. Krueger, E. Warsitz, and R. Haeb-Umbach, “Speech Enhancement With a GSC-Like Structure Employing Eigenvector-Based Transfer Function Ratios Estimation,” <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, vol. 19, no. 1, pp. 206–219, 2011.","short":"A. Krueger, E. Warsitz, R. Haeb-Umbach, IEEE Transactions on Audio, Speech, and Language Processing 19 (2011) 206–219.","chicago":"Krueger, Alexander, Ernst Warsitz, and Reinhold Haeb-Umbach. “Speech Enhancement With a GSC-Like Structure Employing Eigenvector-Based Transfer Function Ratios Estimation.” <i>IEEE Transactions on Audio, Speech, and Language Processing</i> 19, no. 1 (2011): 206–19. <a href=\"https://doi.org/10.1109/TASL.2010.2047324\">https://doi.org/10.1109/TASL.2010.2047324</a>."}},{"date_created":"2019-04-29T13:07:39Z","type":"conference","keyword":["biomedical measurement","brain","cancer","neurophysiology","phantoms","phase locked loops","piezoelectric actuators","surgery","tactile sensors","transfer functions","tumours","PLL","biomedical tissue differentiation system","brain tumor resection","frequency control","frequency shift","gel-phantom","high sensitivity actuator-sensor system","neurosurgery","phase-locked loop","piezoelectric actuators","piezoelectric bimorph","self-oscillating circuit","sensor sensitivity","tactile differentiation","tactile sensor system","transfer function","tumor boundary","visual differentiation","Biomedical measurements","Circuits","Frequency control","Neoplasms","Neurosurgery","Phase locked loops","Piezoelectric actuators","Surges","Transfer functions","Voltage"],"department":[{"_id":"151"}],"publication":"Frequency Control Symposium, 2008 IEEE International","citation":{"chicago":"Uribe, David Oliva, Ralf Stroop, Tobias Hemsel, and Jörg Wallaschek. “Development of a Biomedical Tissue Differentiation System Using Piezoelectric Actuators.” In <i>Frequency Control Symposium, 2008 IEEE International</i>, 91–94, 2008. <a href=\"https://doi.org/10.1109/FREQ.2008.4622963\">https://doi.org/10.1109/FREQ.2008.4622963</a>.","short":"D.O. Uribe, R. Stroop, T. Hemsel, J. Wallaschek, in: Frequency Control Symposium, 2008 IEEE International, 2008, pp. 91–94.","ieee":"D. O. Uribe, R. Stroop, T. Hemsel, and J. Wallaschek, “Development of a biomedical tissue differentiation system using piezoelectric actuators,” in <i>Frequency Control Symposium, 2008 IEEE International</i>, 2008, pp. 91–94.","apa":"Uribe, D. O., Stroop, R., Hemsel, T., &#38; Wallaschek, J. (2008). Development of a biomedical tissue differentiation system using piezoelectric actuators. In <i>Frequency Control Symposium, 2008 IEEE International</i> (pp. 91–94). <a href=\"https://doi.org/10.1109/FREQ.2008.4622963\">https://doi.org/10.1109/FREQ.2008.4622963</a>","bibtex":"@inproceedings{Uribe_Stroop_Hemsel_Wallaschek_2008, title={Development of a biomedical tissue differentiation system using piezoelectric actuators}, DOI={<a href=\"https://doi.org/10.1109/FREQ.2008.4622963\">10.1109/FREQ.2008.4622963</a>}, booktitle={Frequency Control Symposium, 2008 IEEE International}, author={Uribe, David Oliva and Stroop, Ralf and Hemsel, Tobias and Wallaschek, Jörg}, year={2008}, pages={91–94} }","ama":"Uribe DO, Stroop R, Hemsel T, Wallaschek J. Development of a biomedical tissue differentiation system using piezoelectric actuators. In: <i>Frequency Control Symposium, 2008 IEEE International</i>. ; 2008:91-94. doi:<a href=\"https://doi.org/10.1109/FREQ.2008.4622963\">10.1109/FREQ.2008.4622963</a>","mla":"Uribe, David Oliva, et al. “Development of a Biomedical Tissue Differentiation System Using Piezoelectric Actuators.” <i>Frequency Control Symposium, 2008 IEEE International</i>, 2008, pp. 91–94, doi:<a href=\"https://doi.org/10.1109/FREQ.2008.4622963\">10.1109/FREQ.2008.4622963</a>."},"abstract":[{"lang":"eng","text":"In neurosurgery, delineation of tumor boundaries during resection of brain tumors is of substantial relevance. During operation distinction between tumor and healthy tissue rely on the abilities of the surgeon based on visual and tactile differentiation. In this paper a high sensitivity actuator-sensor system using a piezoelectric bimorph is presented. Frequency shift and transfer function of the bimorphpsilas voltages are detected and evaluated. Sensorpsilas sensitivity is evaluated using two frequency controls strategies: A phase-locked loop (PLL) and a self-oscillating circuit. Results of measurements conducted on gel-phantoms are presented and discussed."}],"quality_controlled":"1","page":"91-94","_id":"9576","language":[{"iso":"eng"}],"doi":"10.1109/FREQ.2008.4622963","user_id":"55222","year":"2008","title":"Development of a biomedical tissue differentiation system using piezoelectric actuators","status":"public","publication_identifier":{"issn":["1075-6787"]},"author":[{"full_name":"Uribe, David Oliva","first_name":"David Oliva","last_name":"Uribe"},{"full_name":"Stroop, Ralf","first_name":"Ralf","last_name":"Stroop"},{"full_name":"Hemsel, Tobias","first_name":"Tobias","last_name":"Hemsel","id":"210"},{"last_name":"Wallaschek","first_name":"Jörg","full_name":"Wallaschek, Jörg"}],"date_updated":"2022-01-06T07:04:16Z"},{"publication":"IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)","citation":{"bibtex":"@inproceedings{Warsitz_Krueger_Haeb-Umbach_2008, title={Speech enhancement with a new generalized eigenvector blocking matrix for application in a generalized sidelobe canceller}, DOI={<a href=\"https://doi.org/10.1109/ICASSP.2008.4517549\">10.1109/ICASSP.2008.4517549</a>}, booktitle={IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)}, author={Warsitz, Ernst and Krueger, Alexander and Haeb-Umbach, Reinhold}, year={2008}, pages={73–76} }","ama":"Warsitz E, Krueger A, Haeb-Umbach R. Speech enhancement with a new generalized eigenvector blocking matrix for application in a generalized sidelobe canceller. In: <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)</i>. ; 2008:73-76. doi:<a href=\"https://doi.org/10.1109/ICASSP.2008.4517549\">10.1109/ICASSP.2008.4517549</a>","mla":"Warsitz, Ernst, et al. “Speech Enhancement with a New Generalized Eigenvector Blocking Matrix for Application in a Generalized Sidelobe Canceller.” <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)</i>, 2008, pp. 73–76, doi:<a href=\"https://doi.org/10.1109/ICASSP.2008.4517549\">10.1109/ICASSP.2008.4517549</a>.","short":"E. Warsitz, A. Krueger, R. Haeb-Umbach, in: IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008), 2008, pp. 73–76.","chicago":"Warsitz, Ernst, Alexander Krueger, and Reinhold Haeb-Umbach. “Speech Enhancement with a New Generalized Eigenvector Blocking Matrix for Application in a Generalized Sidelobe Canceller.” In <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)</i>, 73–76, 2008. <a href=\"https://doi.org/10.1109/ICASSP.2008.4517549\">https://doi.org/10.1109/ICASSP.2008.4517549</a>.","ieee":"E. Warsitz, A. Krueger, and R. Haeb-Umbach, “Speech enhancement with a new generalized eigenvector blocking matrix for application in a generalized sidelobe canceller,” in <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)</i>, 2008, pp. 73–76.","apa":"Warsitz, E., Krueger, A., &#38; Haeb-Umbach, R. (2008). Speech enhancement with a new generalized eigenvector blocking matrix for application in a generalized sidelobe canceller. In <i>IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2008)</i> (pp. 73–76). <a href=\"https://doi.org/10.1109/ICASSP.2008.4517549\">https://doi.org/10.1109/ICASSP.2008.4517549</a>"},"abstract":[{"text":"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.","lang":"eng"}],"date_created":"2019-07-12T05:31:06Z","type":"conference","keyword":["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"],"department":[{"_id":"54"}],"oa":"1","year":"2008","title":"Speech enhancement with a new generalized eigenvector blocking matrix for application in a generalized sidelobe canceller","status":"public","author":[{"full_name":"Warsitz, Ernst","first_name":"Ernst","last_name":"Warsitz"},{"full_name":"Krueger, Alexander","last_name":"Krueger","first_name":"Alexander"},{"full_name":"Haeb-Umbach, Reinhold","last_name":"Haeb-Umbach","first_name":"Reinhold","id":"242"}],"date_updated":"2022-01-06T06:51:12Z","main_file_link":[{"open_access":"1","url":"https://groups.uni-paderborn.de/nt/pubs/2008/WaKrHa08.pdf"}],"page":"73-76","_id":"11935","language":[{"iso":"eng"}],"user_id":"44006","doi":"10.1109/ICASSP.2008.4517549"},{"status":"public","_id":"11927","page":"1529-1539","volume":15,"user_id":"44006","citation":{"ieee":"E. Warsitz and R. Haeb-Umbach, “Blind Acoustic Beamforming Based on Generalized Eigenvalue Decomposition,” <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, vol. 15, no. 5, pp. 1529–1539, 2007.","apa":"Warsitz, E., &#38; Haeb-Umbach, R. (2007). Blind Acoustic Beamforming Based on Generalized Eigenvalue Decomposition. <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, <i>15</i>(5), 1529–1539. <a href=\"https://doi.org/10.1109/TASL.2007.898454\">https://doi.org/10.1109/TASL.2007.898454</a>","chicago":"Warsitz, Ernst, and Reinhold Haeb-Umbach. “Blind Acoustic Beamforming Based on Generalized Eigenvalue Decomposition.” <i>IEEE Transactions on Audio, Speech, and Language Processing</i> 15, no. 5 (2007): 1529–39. <a href=\"https://doi.org/10.1109/TASL.2007.898454\">https://doi.org/10.1109/TASL.2007.898454</a>.","short":"E. Warsitz, R. Haeb-Umbach, IEEE Transactions on Audio, Speech, and Language Processing 15 (2007) 1529–1539.","mla":"Warsitz, Ernst, and Reinhold Haeb-Umbach. “Blind Acoustic Beamforming Based on Generalized Eigenvalue Decomposition.” <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, vol. 15, no. 5, 2007, pp. 1529–39, doi:<a href=\"https://doi.org/10.1109/TASL.2007.898454\">10.1109/TASL.2007.898454</a>.","bibtex":"@article{Warsitz_Haeb-Umbach_2007, title={Blind Acoustic Beamforming Based on Generalized Eigenvalue Decomposition}, volume={15}, DOI={<a href=\"https://doi.org/10.1109/TASL.2007.898454\">10.1109/TASL.2007.898454</a>}, number={5}, journal={IEEE Transactions on Audio, Speech, and Language Processing}, author={Warsitz, Ernst and Haeb-Umbach, Reinhold}, year={2007}, pages={1529–1539} }","ama":"Warsitz E, Haeb-Umbach R. Blind Acoustic Beamforming Based on Generalized Eigenvalue Decomposition. <i>IEEE Transactions on Audio, Speech, and Language Processing</i>. 2007;15(5):1529-1539. doi:<a href=\"https://doi.org/10.1109/TASL.2007.898454\">10.1109/TASL.2007.898454</a>"},"oa":"1","author":[{"full_name":"Warsitz, Ernst","first_name":"Ernst","last_name":"Warsitz"},{"id":"242","first_name":"Reinhold","last_name":"Haeb-Umbach","full_name":"Haeb-Umbach, Reinhold"}],"year":"2007","title":"Blind Acoustic Beamforming Based on Generalized Eigenvalue Decomposition","intvolume":"        15","date_updated":"2022-01-06T06:51:12Z","language":[{"iso":"eng"}],"main_file_link":[{"url":"https://groups.uni-paderborn.de/nt/pubs/2007/WaHa07.pdf","open_access":"1"}],"doi":"10.1109/TASL.2007.898454","publication":"IEEE Transactions on Audio, Speech, and Language Processing","issue":"5","abstract":[{"text":"Maximizing the output signal-to-noise ratio (SNR) of a sensor array in the presence of spatially colored noise leads to a generalized eigenvalue problem. While this approach has extensively been employed in narrowband (antenna) array beamforming, it is typically not used for broadband (microphone) array beamforming due to the uncontrolled amount of speech distortion introduced by a narrowband SNR criterion. In this paper, we show how the distortion of the desired signal can be controlled by a single-channel post-filter, resulting in a performance comparable to the generalized minimum variance distortionless response beamformer, where arbitrary transfer functions relate the source and the microphones. Results are given both for directional and diffuse noise. A novel gradient ascent adaptation algorithm is presented, and its good convergence properties are experimentally revealed by comparison with alternatives from the literature. A key feature of the proposed beamformer is that it operates blindly, i.e., it neither requires knowledge about the array geometry nor an explicit estimation of the transfer functions from source to sensors or the direction-of-arrival.","lang":"eng"}],"date_created":"2019-07-12T05:30:57Z","department":[{"_id":"54"}],"type":"journal_article","keyword":["acoustic signal processing","arbitrary transfer function","array signal processing","blind acoustic beamforming","direction-of-arrival","direction-of-arrival estimation","eigenvalues and eigenfunctions","generalized eigenvalue decomposition","gradient ascent adaptation algorithm","microphone arrays","microphones","narrowband array beamforming","sensor array","single-channel post-filter","spatially colored noise","transfer functions"]}]