Prof. Dr. rer. nat. Ioannis Iossifidis

AUSGEWÄHLTE PUBLIKATIONEN

• anthropomorphic robot arm anthropomorphism arm movement model artificial skin attractor dynamics approach Autonomous robotics BCI behavior generation direct physical interaction Dynamical systems force sensing haptic interface human anatomy human motor behavior human operators intuition inverse kinematics Machine Learning man machine interaction man-machine-interaction manipulators mechanical structure modeling movement model object recognition operators gesture pervasive design robot manipulator control robot vision robotic assistant sensory channels user modelling

  150 Einträge « ‹ 4 von 15 › »

  2021

  120.

  Schmidt, Marie Dominique; Glasmachers, Tobias; Iossifidis, Ioannis

  Artificially Generated Muscle Signals Proceedings Article

  In: BC21 : Computational Neuroscience & Neurotechnology Bernstein Conference 2021, BCCN Bernstein Network Computational Network, 2021.

  Links | BibTeX | Schlagwörter: BCI, Machine Learning

  @inproceedings{schmidtArtificiallyGeneratedMuscle2021,
  
  title = {Artificially Generated Muscle Signals},
  
  author = {Marie Dominique Schmidt and Tobias Glasmachers and Ioannis Iossifidis},
  
  doi = {10.12751/nncn.bc2021.p111},
  
  year  = {2021},
  
  date = {2021-09-15},
  
  urldate = {2021-09-15},
  
  booktitle = {BC21 : Computational Neuroscience & Neurotechnology Bernstein Conference 2021},
  
  publisher = {BCCN Bernstein Network Computational Network},
  
  keywords = {BCI, Machine Learning},
  
  pubstate = {published},
  
  tppubtype = {inproceedings}
  
  }
  
  

  Schließen

  • doi:10.12751/nncn.bc2021.p111

  Schließen

  119.

  Sziburis, Tim; Blex, Susanne; Glasmachers, Tobias; Rano, Inaki; Iossifidis, Ioannis

  Modelling the Generation of Human Upper-Limb Reaching Trajectories: An Extended Behavioural Attractor Dynamics Approach Proceedings Article

  In: BC21 : Computational Neuroscience & Neurotechnology Bernstein Conference 2021, BCCN Bernstein Network Computational Network, 2021.

  Links | BibTeX | Schlagwörter: BCI, Machine Learning, movement model

  @inproceedings{sziburisModellingGenerationHuman2021,
  
  title = {Modelling the Generation of Human Upper-Limb Reaching Trajectories: An Extended Behavioural Attractor Dynamics Approach},
  
  author = {Tim Sziburis and Susanne Blex and Tobias Glasmachers and Inaki Rano and Ioannis Iossifidis},
  
  doi = {10.12751/nncn.bc2021.p078},
  
  year  = {2021},
  
  date = {2021-09-15},
  
  urldate = {2021-09-15},
  
  booktitle = {BC21 : Computational Neuroscience & Neurotechnology Bernstein Conference 2021},
  
  publisher = {BCCN Bernstein Network Computational Network},
  
  keywords = {BCI, Machine Learning, movement model},
  
  pubstate = {published},
  
  tppubtype = {inproceedings}
  
  }
  
  

  Schließen

  • doi:10.12751/nncn.bc2021.p078

  Schließen

  118.

  Ali, Omair; Saif-ur-Rehman, Muhammad; Dyck, Susanne; Glasmachers, Tobias; Iossifidis, Ioannis; Klaes, Christian

  Anchored-STFT and GNAA: An Extension of STFT in Conjunction with an Adversarial Data Augmentation Technique for the Decoding of Neural Signals Artikel

  In: arXiv:2011.14694 [cs, q-bio], 2021.

  Abstract | BibTeX | Schlagwörter: BCI, Machine Learning, Quantitative Biology, Quantitative Methods

  @article{aliAnchoredSTFTGNAAExtension2021,
  
  title = {Anchored-STFT and GNAA: An Extension of STFT in Conjunction with an Adversarial Data Augmentation Technique for the Decoding of Neural Signals},
  
  author = {Omair Ali and Muhammad Saif-ur-Rehman and Susanne Dyck and Tobias Glasmachers and Ioannis Iossifidis and Christian Klaes},
  
  year  = {2021},
  
  date = {2021-08-01},
  
  urldate = {2021-08-01},
  
  journal = {arXiv:2011.14694 [cs, q-bio]},
  
  abstract = {Brain-computer interfaces (BCIs) enable communication between humans and machines by translating brain activity into control commands. Electroencephalography (EEG) signals are one of the most used brain signals in non-invasive BCI applications but are often contaminated with noise. Therefore, it is possible that meaningful patterns for classifying EEG signals are deeply hidden. State-of-the-art deep-learning algorithms are successful in learning hidden, meaningful patterns. However, the quality and the quantity of the presented inputs is pivotal. Here, we propose a novel feature extraction method called anchored Short Time Fourier Transform (anchored-STFT), which is an advanced version of STFT, as it minimizes the trade-off between temporal and spectral resolution presented by STFT. In addition, we propose a novel augmentation method, called gradient norm adversarial augmentation (GNAA). GNAA is not only an augmentation method but is also used to harness adversarial inputs in EEG data, which not only improves the classification accuracy but also enhances the robustness of the classifier. In addition, we also propose a new CNN architecture, namely Skip-Net, for the classification of EEG signals. The proposed pipeline outperforms all state-of-the-art methods and yields an average classification accuracy of 90.7 % and 89.54 % on BCI competition II dataset III and BCI competition IV dataset 2b, respectively.},
  
  keywords = {BCI, Machine Learning, Quantitative Biology, Quantitative Methods},
  
  pubstate = {published},
  
  tppubtype = {article}
  
  }
  
  

  Schließen

  Brain-computer interfaces (BCIs) enable communication between humans and machines by translating brain activity into control commands. Electroencephalography (EEG) signals are one of the most used brain signals in non-invasive BCI applications but are often contaminated with noise. Therefore, it is possible that meaningful patterns for classifying EEG signals are deeply hidden. State-of-the-art deep-learning algorithms are successful in learning hidden, meaningful patterns. However, the quality and the quantity of the presented inputs is pivotal. Here, we propose a novel feature extraction method called anchored Short Time Fourier Transform (anchored-STFT), which is an advanced version of STFT, as it minimizes the trade-off between temporal and spectral resolution presented by STFT. In addition, we propose a novel augmentation method, called gradient norm adversarial augmentation (GNAA). GNAA is not only an augmentation method but is also used to harness adversarial inputs in EEG data, which not only improves the classification accuracy but also enhances the robustness of the classifier. In addition, we also propose a new CNN architecture, namely Skip-Net, for the classification of EEG signals. The proposed pipeline outperforms all state-of-the-art methods and yields an average classification accuracy of 90.7 % and 89.54 % on BCI competition II dataset III and BCI competition IV dataset 2b, respectively.

  Schließen

  117.

  Doliwa, Sebastian; Hussain, Muhammad Ayaz; Sziburis, Tim; Iossifidis, Ioannis

  Biologically Inspired Model for Timed Motion in Robotic Systems Artikel

  In: arXiv:2106.15864 [cs, math], 2021.

  Abstract | BibTeX | Schlagwörter: attractor dynamics approach, Autonomous robotics, Dynamical systems

  @article{doliwaBiologicallyInspiredModel2021,
  
  title = {Biologically Inspired Model for Timed Motion in Robotic Systems},
  
  author = {Sebastian Doliwa and Muhammad Ayaz Hussain and Tim Sziburis and Ioannis Iossifidis},
  
  year  = {2021},
  
  date = {2021-07-01},
  
  urldate = {2021-07-01},
  
  journal = {arXiv:2106.15864 [cs, math]},
  
  abstract = {The goal of this work is the development of a motion model for sequentially timed movement actions in robotic systems under specific consideration of temporal stabilization, that is maintaining an approximately constant overall movement time (isochronous behavior). This is demonstrated both in simulation and on a physical robotic system for the task of intercepting a moving target in three-dimensional space. Motivated from humanoid motion, timing plays a vital role to generate a naturalistic behavior in interaction with the dynamic environment as well as adaptively planning and executing action sequences on-line. In biological systems, many of the physiological and anatomical functions follow a particular level of periodicity and stabilization, which exhibit a certain extent of resilience against external disturbances. A main aspect thereof is stabilizing movement timing against limited perturbations. Especially human arm movement, namely when it is tasked to reach a certain goal point, pose or configuration, shows a stabilizing behavior. This work incorporates the utilization of an extended Kalman filter (EKF) which was implemented to predict the target position while coping with non-linear system dynamics. The periodicity and temporal stabilization in biological systems was artificially generated by a Hopf oscillator, yielding a sinusoidal velocity profile for smooth and repeatable motion.},
  
  keywords = {attractor dynamics approach, Autonomous robotics, Dynamical systems},
  
  pubstate = {published},
  
  tppubtype = {article}
  
  }
  
  

  Schließen

  The goal of this work is the development of a motion model for sequentially timed movement actions in robotic systems under specific consideration of temporal stabilization, that is maintaining an approximately constant overall movement time (isochronous behavior). This is demonstrated both in simulation and on a physical robotic system for the task of intercepting a moving target in three-dimensional space. Motivated from humanoid motion, timing plays a vital role to generate a naturalistic behavior in interaction with the dynamic environment as well as adaptively planning and executing action sequences on-line. In biological systems, many of the physiological and anatomical functions follow a particular level of periodicity and stabilization, which exhibit a certain extent of resilience against external disturbances. A main aspect thereof is stabilizing movement timing against limited perturbations. Especially human arm movement, namely when it is tasked to reach a certain goal point, pose or configuration, shows a stabilizing behavior. This work incorporates the utilization of an extended Kalman filter (EKF) which was implemented to predict the target position while coping with non-linear system dynamics. The periodicity and temporal stabilization in biological systems was artificially generated by a Hopf oscillator, yielding a sinusoidal velocity profile for smooth and repeatable motion.

  Schließen

  116.

  Lehmler, Stephan Johann; Saif-ur-Rehman, Muhammad; Glasmachers, Tobias; Iossifidis, Ioannis

  Deep Transfer-Learning for patient specific model re-calibration: Application to sEMG-Classification Artikel

  In: 2021.

  Links | BibTeX | Schlagwörter: BCI, Computational Complexity, Deep Transfer-Learning, Machine Learning

  @article{lehmler2021deep,
  
  title = {Deep Transfer-Learning for patient specific model re-calibration: Application to sEMG-Classification},
  
  author = {Stephan Johann Lehmler and Muhammad Saif-ur-Rehman and Tobias Glasmachers and Ioannis Iossifidis},
  
  url = {https://api.semanticscholar.org/CorpusID:245634948},
  
  year  = {2021},
  
  date = {2021-01-01},
  
  urldate = {2021-01-01},
  
  keywords = {BCI, Computational Complexity, Deep Transfer-Learning, Machine Learning},
  
  pubstate = {published},
  
  tppubtype = {article}
  
  }
  
  

  Schließen

  • https://api.semanticscholar.org/CorpusID:245634948

  Schließen

  2020

  115.

  Hussain, Muhammad Ayaz; Saif-ur-Rehman, Muhammad; Klaes, Christian; Iossifidis, Ioannis

  Comparison of Anomaly Detection between Statistical Method and Undercomplete Proceedings Article

  In: IEEE IInternational Congress on Big Data, S. 32–38, Los Angeles, USA, 2020.

  Links | BibTeX | Schlagwörter: Anomaly Detection, Autoencoder, Machine Learning

  @inproceedings{Hussain2020,
  
  title = {Comparison of Anomaly Detection between Statistical Method and Undercomplete},
  
  author = {Muhammad Ayaz Hussain and Muhammad Saif-ur-Rehman and Christian Klaes and Ioannis Iossifidis},
  
  doi = {https://doi.org/10.1145/3404687.3404689},
  
  year  = {2020},
  
  date = {2020-01-01},
  
  urldate = {2020-01-01},
  
  booktitle = {IEEE IInternational Congress on Big Data},
  
  pages = {32--38},
  
  address = {Los Angeles, USA},
  
  keywords = {Anomaly Detection, Autoencoder, Machine Learning},
  
  pubstate = {published},
  
  tppubtype = {inproceedings}
  
  }
  
  

  Schließen

  • doi:https://doi.org/10.1145/3404687.3404689

  Schließen

  114.

  Ali, Omair; Saif-ur-Rehman, Muhammad; Dyck, Susanne; Glasmachers, Tobias; Iossifidis, Ioannis; Klaes, Christian

  Improving the performance of EEG decoding using anchored-STFT in conjunction with gradient norm adversarial augmentation Artikel

  In: arXiv preprint arXiv:2011.14694, 2020.

  BibTeX | Schlagwörter: Adversarial NN, BCI, EEG, Machine Learning

  @article{ali2020improving,
  
  title = {Improving the performance of EEG decoding using anchored-STFT in conjunction with gradient norm adversarial augmentation},
  
  author = {Omair Ali and Muhammad Saif-ur-Rehman and Susanne Dyck and Tobias Glasmachers and Ioannis Iossifidis and Christian Klaes},
  
  year  = {2020},
  
  date = {2020-01-01},
  
  urldate = {2020-01-01},
  
  journal = {arXiv preprint arXiv:2011.14694},
  
  keywords = {Adversarial NN, BCI, EEG, Machine Learning},
  
  pubstate = {published},
  
  tppubtype = {article}
  
  }
  
  

  Schließen

  113.

  Saif-ur-Rehman, Muhammad; Ali, Omair; Dyck, Susanne; Lienkämper, Robin; Metzler, Marita; Parpaley, Yaroslav; Wellmer, Jörg; Liu, Charles; Lee, Brian; Kellis, Spencer; Andersen, Richard; Iossifidis, Ioannis; Glasmachers, Tobias; Klaes, Christian

  SpikeDeep-Classifier: A deep-learning based fully automatic offline spike sorting algorithm Artikel

  In: Journal of Neural Engineering, 2020.

  Abstract | Links | BibTeX | Schlagwörter: BCI, CNN, Machine Learning, Spike Sorting

  @article{10.1088/1741-2552/abc8d4,
  
  title = {SpikeDeep-Classifier: A deep-learning based fully automatic offline spike sorting algorithm},
  
  author = {Muhammad Saif-ur-Rehman and Omair Ali and Susanne Dyck and Robin Lienkämper and Marita Metzler and Yaroslav Parpaley and Jörg Wellmer and Charles Liu and Brian Lee and Spencer Kellis and Richard Andersen and Ioannis Iossifidis and Tobias Glasmachers and Christian Klaes},
  
  url = {http://iopscience.iop.org/article/10.1088/1741-2552/abc8d4},
  
  year  = {2020},
  
  date = {2020-01-01},
  
  urldate = {2020-01-01},
  
  journal = {Journal of Neural Engineering},
  
  abstract = {Objective. Advancements in electrode design have resulted in micro-electrode arrays with hundreds of channels for single cell recordings. In the resulting electrophysiological recordings, each implanted electrode can record spike activity (SA) of one or more neurons along with background activity (BA). The aim of this study is to isolate SA of each neural source. This process is called spike sorting or spike classification. Advanced spike sorting algorithms are time consuming because of the human intervention at various stages of the pipeline. Current approaches lack generalization because the values of hyperparameters are not fixed, even for multiple recording sessions of the same subject. In this study, a fully automatic spike sorting algorithm called “SpikeDeep-Classifier” is proposed. The values of hyperparameters remain fixed for all the evaluation data. Approach. The proposed approach is based on our previous study (SpikeDeeptector) and a novel background activity rejector (BAR), which are both supervised learning algorithms and an unsupervised learning algorithm (K-means). SpikeDeeptector and BAR are used to extract meaningful channels and remove BA from the extracted meaningful channels, respectively. The process of clustering becomes straight-forward once the BA is completely removed from the data. Then, K-means with a predefined maximum number of clusters is applied on the remaining data originating from neural sources only. Lastly, a similarity-based criterion and a threshold are used to keep distinct clusters and merge similar looking clusters. The proposed approach is called cluster accept or merge (CAOM) and it has only two hyperparameters (maximum number of clusters and similarity threshold) which are kept fixed for all the evaluation data after tuning. Main Results. We compared the results of our algorithm with ground-truth labels. The algorithm is evaluated on data of human patients and publicly available labeled non-human primates (NHPs) datasets. The average accuracy of BAR on datasets of human patients is 92.3% which is further reduced to 88.03% after (K-means + CAOM). In addition, the average accuracy of BAR on a publicly available labeled dataset of NHPs is 95.40% which reduces to 86.95% after (K-mean + CAOM). Lastly, we compared the performance of the SpikeDeep-Classifier with two human experts, where SpikeDeep-Classifier has produced comparable results. Significance. The results demonstrate that “SpikeDeep-Classifier” possesses the ability to generalize well on a versatile dataset and henceforth provides a generalized well on a versatile dataset and henceforth provides a generalized and fully automated solution to offline spike sorting.},
  
  keywords = {BCI, CNN, Machine Learning, Spike Sorting},
  
  pubstate = {published},
  
  tppubtype = {article}
  
  }
  
  

  Schließen

  Objective. Advancements in electrode design have resulted in micro-electrode arrays with hundreds of channels for single cell recordings. In the resulting electrophysiological recordings, each implanted electrode can record spike activity (SA) of one or more neurons along with background activity (BA). The aim of this study is to isolate SA of each neural source. This process is called spike sorting or spike classification. Advanced spike sorting algorithms are time consuming because of the human intervention at various stages of the pipeline. Current approaches lack generalization because the values of hyperparameters are not fixed, even for multiple recording sessions of the same subject. In this study, a fully automatic spike sorting algorithm called “SpikeDeep-Classifier” is proposed. The values of hyperparameters remain fixed for all the evaluation data. Approach. The proposed approach is based on our previous study (SpikeDeeptector) and a novel background activity rejector (BAR), which are both supervised learning algorithms and an unsupervised learning algorithm (K-means). SpikeDeeptector and BAR are used to extract meaningful channels and remove BA from the extracted meaningful channels, respectively. The process of clustering becomes straight-forward once the BA is completely removed from the data. Then, K-means with a predefined maximum number of clusters is applied on the remaining data originating from neural sources only. Lastly, a similarity-based criterion and a threshold are used to keep distinct clusters and merge similar looking clusters. The proposed approach is called cluster accept or merge (CAOM) and it has only two hyperparameters (maximum number of clusters and similarity threshold) which are kept fixed for all the evaluation data after tuning. Main Results. We compared the results of our algorithm with ground-truth labels. The algorithm is evaluated on data of human patients and publicly available labeled non-human primates (NHPs) datasets. The average accuracy of BAR on datasets of human patients is 92.3% which is further reduced to 88.03% after (K-means + CAOM). In addition, the average accuracy of BAR on a publicly available labeled dataset of NHPs is 95.40% which reduces to 86.95% after (K-mean + CAOM). Lastly, we compared the performance of the SpikeDeep-Classifier with two human experts, where SpikeDeep-Classifier has produced comparable results. Significance. The results demonstrate that “SpikeDeep-Classifier” possesses the ability to generalize well on a versatile dataset and henceforth provides a generalized well on a versatile dataset and henceforth provides a generalized and fully automated solution to offline spike sorting.

  Schließen

  • http://iopscience.iop.org/article/10.1088/1741-2552/abc8d4

  Schließen

  2019

  112.

  Hussain, Muhammad Ayaz; Saif-ur-Rehman, Muhammad; Klaes, Christian; Iossifidis, Ioannis

  Comparison of Anomaly Detection between Statistical Method and Undercomplete Proceedings Article

  In: IEEE IInternational Congress on Big Data, Los Angeles, USA, 2019.

  BibTeX | Schlagwörter: Anomaly Detection, Autoencoder, Machine Learning

  @inproceedings{Hussain2019,
  
  title = {Comparison of Anomaly Detection between Statistical Method and Undercomplete},
  
  author = {Muhammad Ayaz Hussain and Muhammad Saif-ur-Rehman and Christian Klaes and Ioannis Iossifidis},
  
  year  = {2019},
  
  date = {2019-01-01},
  
  urldate = {2019-01-01},
  
  booktitle = {IEEE IInternational Congress on Big Data},
  
  address = {Los Angeles, USA},
  
  keywords = {Anomaly Detection, Autoencoder, Machine Learning},
  
  pubstate = {published},
  
  tppubtype = {inproceedings}
  
  }
  
  

  Schließen

  111.

  Saif-ur-Rehman, Muhammad; Lienkämper, Robin; Parpaley, Yaroslav; Wellmer, Jörg; Liu, Charles; Lee, Brian; Kellis, Spencer; Andersen, Richard; Iossifidis, Ioannis; Glasmachers, Tobias; Klaes, Christian

  SpikeDeeptector: a deep-learning based method for detection of neural spiking activity Artikel

  In: Journal of Neural Engineering, Bd. 16, Nr. 5, S. 056003, 2019.

  Abstract | Links | BibTeX | Schlagwörter: BCI, CNN, Data Reduction, Machine Learning, Spike Sorting

  @article{Saif-ur-Rehman2019,
  
  title = {SpikeDeeptector: a deep-learning based method for detection of neural spiking activity},
  
  author = {Muhammad Saif-ur-Rehman and Robin Lienkämper and Yaroslav Parpaley and Jörg Wellmer and Charles Liu and Brian Lee and Spencer Kellis and Richard Andersen and Ioannis Iossifidis and Tobias Glasmachers and Christian Klaes},
  
  url = {https://iopscience.iop.org/article/10.1088/1741-2552/ab1e63/meta},
  
  doi = {10.1088/1741-2552/ab1e63},
  
  year  = {2019},
  
  date = {2019-01-01},
  
  urldate = {2019-01-01},
  
  journal = {Journal of Neural Engineering},
  
  volume = {16},
  
  number = {5},
  
  pages = {056003},
  
  abstract = {Objective . In electrophysiology, microelectrodes are the primary source for recording neural data (single unit activity). These microelectrodes can be implanted individually or in the form of arrays containing dozens to hundreds of channels. Recordings of some channels contain neural activity, which are often contaminated with noise. Another fraction of channels does not record any neural data, but only noise. By noise, we mean physiological activities unrelated to spiking, including technical artifacts and neural activities of neurons that are too far away from the electrode to be usefully processed. For further analysis, an automatic identification and continuous tracking of channels containing neural data is of great significance for many applications, e.g. automated selection of neural channels during online and offline spike sorting. Automated spike detection and sorting is also critical for online decoding in brain–computer interface (BCI) applications, in which on...},
  
  keywords = {BCI, CNN, Data Reduction, Machine Learning, Spike Sorting},
  
  pubstate = {published},
  
  tppubtype = {article}
  
  }
  
  

  Schließen

  Objective . In electrophysiology, microelectrodes are the primary source for recording neural data (single unit activity). These microelectrodes can be implanted individually or in the form of arrays containing dozens to hundreds of channels. Recordings of some channels contain neural activity, which are often contaminated with noise. Another fraction of channels does not record any neural data, but only noise. By noise, we mean physiological activities unrelated to spiking, including technical artifacts and neural activities of neurons that are too far away from the electrode to be usefully processed. For further analysis, an automatic identification and continuous tracking of channels containing neural data is of great significance for many applications, e.g. automated selection of neural channels during online and offline spike sorting. Automated spike detection and sorting is also critical for online decoding in brain–computer interface (BCI) applications, in which on...

  Schließen

  • https://iopscience.iop.org/article/10.1088/1741-2552/ab1e63/meta
  • doi:10.1088/1741-2552/ab1e63

  Schließen

  150 Einträge « ‹ 4 von 15 › »