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  1. Artikel: Robust image descriptor for machine learning based data reduction in serial crystallography.

    Rahmani, Vahid / Nawaz, Shah / Pennicard, David / Graafsma, Heinz

    Journal of applied crystallography

    2024  Band 57, Heft Pt 2, Seite(n) 413–430

    Abstract: Serial crystallography experiments at synchrotron and X-ray free-electron laser (XFEL) sources are producing crystallographic data sets of ever-increasing volume. While these experiments have large data sets and high-frame-rate detectors (around 3520 ... ...

    Abstract Serial crystallography experiments at synchrotron and X-ray free-electron laser (XFEL) sources are producing crystallographic data sets of ever-increasing volume. While these experiments have large data sets and high-frame-rate detectors (around 3520 frames per second), only a small percentage of the data are useful for downstream analysis. Thus, an efficient and real-time data classification pipeline is essential to differentiate reliably between useful and non-useful images, typically known as 'hit' and 'miss', respectively, and keep only hit images on disk for further analysis such as peak finding and indexing. While feature-point extraction is a key component of modern approaches to image classification, existing approaches require computationally expensive patch preprocessing to handle perspective distortion. This paper proposes a pipeline to categorize the data, consisting of a real-time feature extraction algorithm called modified and parallelized FAST (MP-FAST), an image descriptor and a machine learning classifier. For parallelizing the primary operations of the proposed pipeline, central processing units, graphics processing units and field-programmable gate arrays are implemented and their performances compared. Finally, MP-FAST-based image classification is evaluated using a multi-layer perceptron on various data sets, including both synthetic and experimental data. This approach demonstrates superior performance compared with other feature extractors and classifiers.
    Sprache Englisch
    Erscheinungsdatum 2024-03-26
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 2020879-0
    ISSN 1600-5767 ; 0021-8898
    ISSN (online) 1600-5767
    ISSN 0021-8898
    DOI 10.1107/S160057672400147X
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  2. Artikel: Data reduction for X-ray serial crystallography using machine learning.

    Rahmani, Vahid / Nawaz, Shah / Pennicard, David / Setty, Shabarish Pala Ramakantha / Graafsma, Heinz

    Journal of applied crystallography

    2023  Band 56, Heft Pt 1, Seite(n) 200–213

    Abstract: Serial crystallography experiments produce massive amounts of experimental data. Yet in spite of these large-scale data sets, only a small percentage of the data are useful for downstream analysis. Thus, it is essential to differentiate reliably between ... ...

    Abstract Serial crystallography experiments produce massive amounts of experimental data. Yet in spite of these large-scale data sets, only a small percentage of the data are useful for downstream analysis. Thus, it is essential to differentiate reliably between acceptable data (hits) and unacceptable data (misses). To this end, a novel pipeline is proposed to categorize the data, which extracts features from the images, summarizes these features with the 'bag of visual words' method and then classifies the images using machine learning. In addition, a novel study of various feature extractors and machine learning classifiers is presented, with the aim of finding the best feature extractor and machine learning classifier for serial crystallography data. The study reveals that the oriented FAST and rotated BRIEF (ORB) feature extractor with a multilayer perceptron classifier gives the best results. Finally, the ORB feature extractor with multilayer perceptron is evaluated on various data sets including both synthetic and experimental data, demonstrating superior performance compared with other feature extractors and classifiers.
    Sprache Englisch
    Erscheinungsdatum 2023-02-01
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 2020879-0
    ISSN 1600-5767 ; 0021-8898
    ISSN (online) 1600-5767
    ISSN 0021-8898
    DOI 10.1107/S1600576722011748
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  3. Artikel: Explainable machine learning for diffraction patterns.

    Nawaz, Shah / Rahmani, Vahid / Pennicard, David / Setty, Shabarish Pala Ramakantha / Klaudel, Barbara / Graafsma, Heinz

    Journal of applied crystallography

    2023  Band 56, Heft Pt 5, Seite(n) 1494–1504

    Abstract: Serial crystallography experiments at X-ray free-electron laser facilities produce massive amounts of data but only a fraction of these data are useful for downstream analysis. Thus, it is essential to differentiate between acceptable and unacceptable ... ...

    Abstract Serial crystallography experiments at X-ray free-electron laser facilities produce massive amounts of data but only a fraction of these data are useful for downstream analysis. Thus, it is essential to differentiate between acceptable and unacceptable data, generally known as 'hit' and 'miss', respectively. Image classification methods from artificial intelligence, or more specifically convolutional neural networks (CNNs), classify the data into hit and miss categories in order to achieve data reduction. The quantitative performance established in previous work indicates that CNNs successfully classify serial crystallography data into desired categories [Ke, Brewster, Yu, Ushizima, Yang & Sauter (2018).
    Sprache Englisch
    Erscheinungsdatum 2023-09-20
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 2020879-0
    ISSN 1600-5767 ; 0021-8898
    ISSN (online) 1600-5767
    ISSN 0021-8898
    DOI 10.1107/S1600576723007446
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  4. Artikel: X-ray imaging detectors for synchrotron and XFEL sources.

    Hatsui, Takaki / Graafsma, Heinz

    IUCrJ

    2015  Band 2, Heft Pt 3, Seite(n) 371–383

    Abstract: Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve ... ...

    Abstract Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors.
    Sprache Englisch
    Erscheinungsdatum 2015-04-10
    Erscheinungsland England
    Dokumenttyp Journal Article ; Review
    ZDB-ID 2754953-7
    ISSN 2052-2525
    ISSN 2052-2525
    DOI 10.1107/S205225251500010X
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  5. Buch ; Konferenzbeitrag: Radiation imaging detectors 2005

    Graafsma, Heinz

    proceedings of the 7th International Workshop on Radiation Imaging Detectors, ESRF, Grenoble, France, July 4 - 7, 2005 ; 7th IWORID

    (Nuclear instruments & methods in physics research : Section A, Accelerators, spectrometers, detectors and associated equipment ; 563.2006,1)

    2006  

    Titelvarianten seventh
    Körperschaft International Workshop on Radiation Imaging Detectors
    Veranstaltung/Kongress IWORID (7, 2005.07.04-07, Grenoble) ; International Workshop on Radiation Imaging Detectors (7, 2005.07.04-07, Grenoble)
    Verfasserangabe Ed.: Heinz Graafsma
    Serientitel Nuclear instruments & methods in physics research : Section A, Accelerators, spectrometers, detectors and associated equipment ; 563.2006,1
    Sprache Englisch
    Umfang XVIII, 290 S., Ill., graph. Darst.
    Verlag Elsevier
    Erscheinungsort Amsterdam u.a.
    Dokumenttyp Buch ; Konferenzbeitrag
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  6. Artikel ; Online: Single and multi-pulse based X-ray photon correlation spectroscopy.

    Jo, Wonhyuk / Stern, Stephan / Westermeier, Fabian / Rysov, Rustam / Riepp, Matthias / Schmehr, Julian / Lange, Jörn / Becker, Julian / Sprung, Michael / Laurus, Torsten / Graafsma, Heinz / Lokteva, Irina / Grübel, Gerhard / Roseker, Wojciech

    Optics express

    2023  Band 31, Heft 2, Seite(n) 3315–3324

    Abstract: The ability of pulsed nature of synchrotron radiation opens up the possibility of studying microsecond dynamics in complex materials via speckle-based techniques. Here, we present the study of measuring the dynamics of a colloidal system by combining ... ...

    Abstract The ability of pulsed nature of synchrotron radiation opens up the possibility of studying microsecond dynamics in complex materials via speckle-based techniques. Here, we present the study of measuring the dynamics of a colloidal system by combining single and multiple X-ray pulses of a storage ring. In addition, we apply speckle correlation techniques at various pulse patterns to collect correlation functions from nanoseconds to milliseconds. The obtained sample dynamics from all correlation techniques at different pulse patterns are in very good agreement with the expected dynamics of Brownian motions of silica nanoparticles in water. Our study will pave the way for future pulsed X-ray investigations at various synchrotron X-ray sources using individual X-ray pulse patterns.
    Sprache Englisch
    Erscheinungsdatum 2023-01-16
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.477774
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  7. Artikel: Nanosecond X-ray photon correlation spectroscopy using pulse time structure of a storage-ring source.

    Jo, Wonhyuk / Westermeier, Fabian / Rysov, Rustam / Leupold, Olaf / Schulz, Florian / Tober, Steffen / Markmann, Verena / Sprung, Michael / Ricci, Allesandro / Laurus, Torsten / Aschkan, Allahgholi / Klyuev, Alexander / Trunk, Ulrich / Graafsma, Heinz / Grübel, Gerhard / Roseker, Wojciech

    IUCrJ

    2021  Band 8, Heft Pt 1, Seite(n) 124–130

    Abstract: X-ray photon correlation spectroscopy (XPCS) is a routine technique to study slow dynamics in complex systems at storage-ring sources. Achieving nanosecond time resolution with the conventional XPCS technique is, however, still an experimentally ... ...

    Abstract X-ray photon correlation spectroscopy (XPCS) is a routine technique to study slow dynamics in complex systems at storage-ring sources. Achieving nanosecond time resolution with the conventional XPCS technique is, however, still an experimentally challenging task requiring fast detectors and sufficient photon flux. Here, the result of a nanosecond XPCS study of fast colloidal dynamics is shown by employing an adaptive gain integrating pixel detector (AGIPD) operated at frame rates of the intrinsic pulse structure of the storage ring. Correlation functions from single-pulse speckle patterns with the shortest correlation time of 192 ns have been calculated. These studies provide an important step towards routine fast XPCS studies at storage rings.
    Sprache Englisch
    Erscheinungsdatum 2021-01-01
    Erscheinungsland England
    Dokumenttyp Journal Article
    ZDB-ID 2754953-7
    ISSN 2052-2525
    ISSN 2052-2525
    DOI 10.1107/S2052252520015778
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  8. Buch ; Online: In-situ Materials Characterization

    Ziegler, Alexander / Frenken, Joost W.M / Graafsma, Heinz / Zhang, Xiao Feng

    Across Spatial and Temporal Scales

    (Springer Series in Materials Science ; 193)

    2014  

    Abstract: The behavior of nanoscale materials can change rapidly with time either because the environment changes rapidly, or because the influence of the environment propagates quickly across the intrinsically small dimensions of nanoscale materials. Extremely ... ...

    Verfasserangabe edited by Alexander Ziegler, Heinz Graafsma, Xiao Feng Zhang, Joost W.M. Frenken
    Serientitel Springer Series in Materials Science ; 193
    Abstract The behavior of nanoscale materials can change rapidly with time either because the environment changes rapidly, or because the influence of the environment propagates quickly across the intrinsically small dimensions of nanoscale materials. Extremely fast time resolution studies using X-rays, electrons and neutrons are of very high interest to many researchers and is a fast-evolving and interesting field for the study of dynamic processes. Therefore, in situ structural characterization and measurements of structure-property relationships covering several decades of length and time scales (from atoms to millimeters and femtoseconds to hours) with high spatial and temporal resolutions are crucially important to understand the synthesis and behavior of multidimensional materials. The techniques described in this book will permit access to the real-time dynamics of materials, surface processes, and chemical and biological reactions at various time scales. This book provides an interdisciplinary reference for research using in situ techniques to capture the real-time structural and property responses of materials to surrounding fields using electron, optical, and x-ray microscopies (e.g., scanning, transmission, and low-energy electron microscopy, and scanning probe microscopy), or in the scattering realm with x-ray, neutron and electron diffraction
    Schlagwörter Materials ; Nanotechnology ; Physics ; Surfaces (Physics) ; Technik / Wissen Materialwissenschaften ; Technik / Wissen Nanotechnologie ; Technik / Wissen Physik
    Sprache Englisch
    Umfang Online-Ressource (XI, 256 p. 124 illus., 78 illus. in color), online resource
    Verlag Springer Berlin Heidelberg
    Erscheinungsort Berlin, Heidelberg ;s.l
    Dokumenttyp Buch ; Online
    Anmerkung Description based upon print version of record
    ISBN 9783642451515 ; 9783642451522 ; 3642451519 ; 3642451527
    DOI 10.1007/978-3-642-45152-2
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  9. Buch ; Online: In-situ Materials Characterization

    Ziegler, Alexander / Frenken, Joost W.M / Graafsma, Heinz / Zhang, Xiao Feng

    Across Spatial and Temporal Scales

    (Springer Series in Materials Science ; 193)

    2014  

    Abstract: The behavior of nanoscale materials can change rapidly with time either because the environment changes rapidly, or because the influence of the environment propagates quickly across the intrinsically small dimensions of nanoscale materials. Extremely ... ...

    Verfasserangabe edited by Alexander Ziegler, Heinz Graafsma, Xiao Feng Zhang, Joost W.M. Frenken
    Serientitel Springer Series in Materials Science ; 193
    Abstract The behavior of nanoscale materials can change rapidly with time either because the environment changes rapidly, or because the influence of the environment propagates quickly across the intrinsically small dimensions of nanoscale materials. Extremely fast time resolution studies using X-rays, electrons and neutrons are of very high interest to many researchers and is a fast-evolving and interesting field for the study of dynamic processes. Therefore, in situ structural characterization and measurements of structure-property relationships covering several decades of length and time scales (from atoms to millimeters and femtoseconds to hours) with high spatial and temporal resolutions are crucially important to understand the synthesis and behavior of multidimensional materials. The techniques described in this book will permit access to the real-time dynamics of materials, surface processes, and chemical and biological reactions at various time scales. This book provides an interdisciplinary reference for research using in situ techniques to capture the real-time structural and property responses of materials to surrounding fields using electron, optical, and x-ray microscopies (e.g., scanning, transmission, and low-energy electron microscopy, and scanning probe microscopy), or in the scattering realm with x-ray, neutron and electron diffraction
    Schlagwörter Materials ; Nanotechnology ; Physics ; Surfaces (Physics) ; Technik / Wissen Physik
    Sprache Englisch
    Umfang Online-Ressource (XI, 256 p. 124 illus., 78 illus. in color), online resource
    Verlag Springer Berlin Heidelberg
    Erscheinungsort Berlin, Heidelberg ;s.l
    Dokumenttyp Buch ; Online
    Anmerkung Description based upon print version of record
    ISBN 9783642451515 ; 9783642451522 ; 3642451519 ; 3642451527
    DOI 10.1007/978-3-642-45152-2
    Datenquelle Ehemaliges Sondersammelgebiet Küsten- und Hochseefischerei

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  10. Artikel ; Online: Connecting structure, dynamics and viscosity in sheared soft colloidal liquids: a medley of anisotropic fluctuations.

    Westermeier, Fabian / Pennicard, David / Hirsemann, Helmut / Wagner, Ulrich H / Rau, Christoph / Graafsma, Heinz / Schall, Peter / Lettinga, M Paul / Struth, Bernd

    Soft matter

    2016  Band 12, Heft 1, Seite(n) 171–180

    Abstract: Structural distortion and relaxation are central to any liquid flow. Their full understanding requires simultaneous probing of the mechanical as well as structural and dynamical response. We provide the first full dynamical measurement of the transient ... ...

    Abstract Structural distortion and relaxation are central to any liquid flow. Their full understanding requires simultaneous probing of the mechanical as well as structural and dynamical response. We provide the first full dynamical measurement of the transient structure using combined coherent X-ray scattering and rheology on electrostatically interacting colloidal fluids. We find a stress overshoot during the start-up of shear which is due to the strong anisotropic overstretching and compression of nearest-neighbor distances. The rheological response is reflected in uncorrelated entropy-driven intensity fluctuations. While the structural distortion under steady shear is well described by Smoluchowski theory, we find an increase of the particle dynamics beyond the trivial contribution of flow. After the cessation of shear, the full fluid microstructure and dynamics are restored, both on the structural relaxation timescale. We thus find unique structure-dynamics relations in liquid flow, responsible for the macroscopic rheological behavior of the system.
    Sprache Englisch
    Erscheinungsdatum 2016-01-07
    Erscheinungsland England
    Dokumenttyp Journal Article
    ZDB-ID 2191476-X
    ISSN 1744-6848 ; 1744-683X
    ISSN (online) 1744-6848
    ISSN 1744-683X
    DOI 10.1039/c5sm01707f
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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