scholarly journals Closed-Loop Cognitive-Driven Gain Control of Competing Sounds Using Auditory Attention Decoding

Algorithms ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 287
Author(s):  
Ali Aroudi ◽  
Eghart Fischer ◽  
Maja Serman ◽  
Henning Puder ◽  
Simon Doclo
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Subjective Evaluation ◽  
Gain Control ◽  
Open Loop ◽  
Cognitive Effort ◽  
Auditory Attention ◽  
Significant Difference ◽  
Online Feedback ◽  
Target Speaker

Recent advances have shown that it is possible to identify the target speaker which a listener is attending to using single-trial EEG-based auditory attention decoding (AAD). Most AAD methods have been investigated for an open-loop scenario, where AAD is performed in an offline fashion without presenting online feedback to the listener. In this work, we aim at developing a closed-loop AAD system that allows to enhance a target speaker, suppress an interfering speaker and switch attention between both speakers. To this end, we propose a cognitive-driven adaptive gain controller (AGC) based on real-time AAD. Using the EEG responses of the listener and the speech signals of both speakers, the real-time AAD generates probabilistic attention measures, based on which the attended and the unattended speaker are identified. The AGC then amplifies the identified attended speaker and attenuates the identified unattended speaker, which are presented to the listener via loudspeakers. We investigate the performance of the proposed system in terms of the decoding performance and the signal-to-interference ratio (SIR) improvement. The experimental results show that, although there is a significant delay to detect attention switches, the proposed system is able to improve the SIR between the attended and the unattended speaker. In addition, no significant difference in decoding performance is observed between closed-loop AAD and open-loop AAD. The subjective evaluation results show that the proposed closed-loop cognitive-driven system demands a similar level of cognitive effort to follow the attended speaker, to ignore the unattended speaker and to switch attention between both speakers compared to using open-loop AAD. Closed-loop AAD in an online fashion is feasible and enables the listener to interact with the AGC.

scholarly journals Generic characterization of electrical test benches for AC- and HVDC-connected wind power plants

2020 ◽  
Vol 5 (2) ◽  
pp. 561-575
Author(s):  
Behnam Nouri ◽  
Ömer Göksu ◽  
Vahan Gevorgian ◽  
Poul Ejnar Sørensen
Keyword(s):  
Real Time ◽  
Wind Power ◽  
Wind Turbines ◽  
Closed Loop ◽  
Short Circuit ◽  
Open Loop ◽  
Device Under Test ◽  
Generic Structure ◽  
Electrical Test ◽  
Grid Connection

Abstract. The electrical test and assessment of wind turbines go hand in hand with standards and network connection requirements. In this paper, the generic structure of advanced electrical test benches, including grid emulator or controllable grid interface, wind torque emulator, and device under test, is proposed to harmonize state-of-the-art test sites. On the other hand, modern wind turbines are under development towards new features, concerning grid-forming, black-start, and frequency support capabilities as well as harmonic stability and control interaction considerations, to secure the robustness and stability of renewable-energy-based power systems. Therefore, it is necessary to develop new and revised test standards and methodologies to address the new features of wind turbines. This paper proposes a generic test structure within two main groups, including open-loop and closed-loop tests. The open-loop tests include the IEC 61400-21-1 standard tests as well as the additional proposed test options for the new capabilities of wind turbines, which replicate grid connection compliance tests using open-loop references for the grid emulator. In addition, the closed-loop tests evaluate the device under test as part of a virtual wind power plant and perform real-time simulations considering the grid dynamics. The closed-loop tests concern grid connection topologies consisting of AC and HVDC, as well as different electrical characteristics, including impedance, short-circuit ratio, inertia, and background harmonics. The proposed tests can be implemented using available advanced test benches by adjusting their control systems. The characteristics of a real power system can be emulated by a grid emulator coupled with real-time digital simulator systems through a high-bandwidth power-hardware-in-the-loop interface.

scholarly journals Design Considerations for Long Term Non-invasive Brain Computer Interface Training With Tetraplegic CYBATHLON Pilot

2021 ◽  
Vol 15 ◽  
Author(s):  
Neethu Robinson ◽  
Tushar Chouhan ◽  
Ernest Mihelj ◽  
Paulina Kratka ◽  
Frédéric Debraine ◽  
...  
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Brain Computer Interface ◽  
Brain Activation ◽  
Classification Performance ◽  
Open Loop ◽  
Computer Interface ◽  
Single Subject ◽  
User Engagement

Several studies in the recent past have demonstrated how Brain Computer Interface (BCI) technology can uncover the neural mechanisms underlying various tasks and translate them into control commands. While a multitude of studies have demonstrated the theoretic potential of BCI, a point of concern is that the studies are still confined to lab settings and mostly limited to healthy, able-bodied subjects. The CYBATHLON 2020 BCI race represents an opportunity to further develop BCI design strategies for use in real-time applications with a tetraplegic end user. In this study, as part of the preparation to participate in CYBATHLON 2020 BCI race, we investigate the design aspects of BCI in relation to the choice of its components, in particular, the type of calibration paradigm and its relevance for long-term use. The end goal was to develop a user-friendly and engaging interface suited for long-term use, especially for a spinal-cord injured (SCI) patient. We compared the efficacy of conventional open-loop calibration paradigms with real-time closed-loop paradigms, using pre-trained BCI decoders. Various indicators of performance were analyzed for this study, including the resulting classification performance, game completion time, brain activation maps, and also subjective feedback from the pilot. Our results show that the closed-loop calibration paradigms with real-time feedback is more engaging for the pilot. They also show an indication of achieving better online median classification performance as compared to conventional calibration paradigms (p = 0.0008). We also observe that stronger and more localized brain activation patterns are elicited in the closed-loop paradigm in which the experiment interface closely resembled the end application. Thus, based on this longitudinal evaluation of single-subject data, we demonstrate that BCI-based calibration paradigms with active user-engagement, such as with real-time feedback, could help in achieving better user acceptability and performance.

scholarly journals Real-time synthesis of imagined speech processes from minimally invasive recordings of neural activity

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Miguel Angrick ◽  
Maarten C. Ottenhoff ◽  
Lorenz Diener ◽  
Darius Ivucic ◽  
Gabriel Ivucic ◽  
...  
Keyword(s):  
Real Time ◽  
Neural Activity ◽  
Communication Channel ◽  
Closed Loop ◽  
Open Loop ◽  
Depth Electrodes ◽  
Whispered Speech ◽  
Frontal Activity ◽  
Synthesis Approach

AbstractSpeech neuroprosthetics aim to provide a natural communication channel to individuals who are unable to speak due to physical or neurological impairments. Real-time synthesis of acoustic speech directly from measured neural activity could enable natural conversations and notably improve quality of life, particularly for individuals who have severely limited means of communication. Recent advances in decoding approaches have led to high quality reconstructions of acoustic speech from invasively measured neural activity. However, most prior research utilizes data collected during open-loop experiments of articulated speech, which might not directly translate to imagined speech processes. Here, we present an approach that synthesizes audible speech in real-time for both imagined and whispered speech conditions. Using a participant implanted with stereotactic depth electrodes, we were able to reliably generate audible speech in real-time. The decoding models rely predominately on frontal activity suggesting that speech processes have similar representations when vocalized, whispered, or imagined. While reconstructed audio is not yet intelligible, our real-time synthesis approach represents an essential step towards investigating how patients will learn to operate a closed-loop speech neuroprosthesis based on imagined speech.

scholarly journals Design of a Research Laboratory Drive System for a Synchronous Reluctance Motor for Vector Control and Performance Analysis

Inventions ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 64
Author(s):  
Hamidreza Heidari ◽  
Anton Rassõlkin ◽  
Ants Kallaste ◽  
Toomas Vaimann ◽  
Ekaterina Andriushchenko ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Vector Control ◽  
Real Time ◽  
Research Laboratory ◽  
Closed Loop ◽  
Open Loop ◽  
Drive System ◽  
Control Algorithms ◽  
Synchronous Reluctance Motor ◽  
Reluctance Motor

Motor-drive systems have the most significant share in industrial energy consumption, which requires a deep study in every aspect of the field. This paper presents a synchronous reluctance motor (SynRM) drive system based on Plecs RT box 1. The system’s design provides the opportunity for the open-loop and closed-loop control of the motor and a characteristic performance analysis of the motor. This paper focuses on the hardware implementation of a research laboratory setup and the precise vector control of the SynRM in real-time. The application of the digital controller and inverter to drive SynRM is examined. The voltage, current, and speed transducers were employed for monitoring the protective measures and to control the motor in the closed-loop. The design of the signal conditioning and the intermediary cards for isolation and data acquisition are described in detail. An algorithm is proposed to measure the whole system parameters, including motor, inverter, and cables. Thanks to the RT box 1, the principle of real-time simulation of control algorithms is investigated, and the rapid control prototyping of field-oriented control (FOC) of SynRM was implemented. The simulation of the system was carried out in the Plecs platform, and the results are presented. The experimental results of the implemented control algorithms validate the setup’s performance and the control algorithm. Finally, as a study of the motor’s performance, the efficiency map of the motor is drawn in different speed and torque ranges.

scholarly journals Clinical applications of neurochemical and electrophysiological measurements for closed-loop neurostimulation

2020 ◽  
Vol 49 (1) ◽  
pp. E6 ◽  
Author(s):  
J. Blair Price ◽  
Aaron E. Rusheen ◽  
Abhijeet S. Barath ◽  
Juan M. Rojas Cabrera ◽  
Hojin Shin ◽  
...  
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Neurological Diseases ◽  
Pulse Frequency ◽  
Open Loop ◽  
Compulsive Disorder ◽  
Specific Disease ◽  
Disease States ◽  
Stimulation Parameters ◽  
The Individual

The development of closed-loop deep brain stimulation (DBS) systems represents a significant opportunity for innovation in the clinical application of neurostimulation therapies. Despite the highly dynamic nature of neurological diseases, open-loop DBS applications are incapable of modifying parameters in real time to react to fluctuations in disease states. Thus, current practice for the designation of stimulation parameters, such as duration, amplitude, and pulse frequency, is an algorithmic process. Ideal stimulation parameters are highly individualized and must reflect both the specific disease presentation and the unique pathophysiology presented by the individual. Stimulation parameters currently require a lengthy trial-and-error process to achieve the maximal therapeutic effect and can only be modified during clinical visits. The major impediment to the development of automated, adaptive closed-loop systems involves the selection of highly specific disease-related biomarkers to provide feedback for the stimulation platform. This review explores the disease relevance of neurochemical and electrophysiological biomarkers for the development of closed-loop neurostimulation technologies. Electrophysiological biomarkers, such as local field potentials, have been used to monitor disease states. Real-time measurement of neurochemical substances may be similarly useful for disease characterization. Thus, the introduction of measurable neurochemical analytes has significantly expanded biomarker options for feedback-sensitive neuromodulation systems. The potential use of biomarker monitoring to advance neurostimulation approaches for treatment of Parkinson’s disease, essential tremor, epilepsy, Tourette syndrome, obsessive-compulsive disorder, chronic pain, and depression is examined. Further, challenges and advances in the development of closed-loop neurostimulation technology are reviewed, as well as opportunities for next-generation closed-loop platforms.

Closing the loop

2011 ◽  
pp. 1869-1874
Author(s):  
Roman Hovorka
Keyword(s):  
Type 1 Diabetes ◽  
Real Time ◽  
Closed Loop ◽  
Insulin Delivery ◽  
Insulin Analogues ◽  
Open Loop ◽  
Subcutaneous Insulin ◽  
Closed Loop Systems ◽  
Acting Insulin

The standard therapy of type 1 diabetes is based on multiple daily injections of short- and long acting-insulin analogues accompanied by blood glucose self-monitoring. However, treatment goals identified by the Diabetes Control and Complications Trial are difficult to achieve due, at least in part, to a high risk of hypoglycaemia associated with many currents forms of intensive insulin therapy. Recent technological developments in real-time subcutaneous continuous glucose monitoring (CGM), combined with the continuous subcutaneous insulin infusion (CSII), could potentially reduce this risk. Since late 1990s at least five continuous or semicontinuous glucose monitors have received regulatory approval (1). CGM has been shown to improve glycaemic control in adults with type 1 diabetes, although apparent barriers to effectiveness in children and adolescents remain to be identified (see Chapter 13.4.9.1) (2). The availability of commercial CGM devices has reinvigorated research towards closed-loop systems (3-6), in which insulin is delivered according to real-time needs, as opposed to open-loop systems, which lack real-time responsiveness to changing glucose concentrations. Closed-loop insulin delivery, in which the insulin delivery is informed by the measured glucose concentrations has the potential gradually to revolutionize the management of type 1 diabetes by reducing or eliminating the risk of hypoglycaemia while achieving near-normal glucose levels. A closed-loop system, also called the ‘artificial pancreas’, comprises three components: a CGM device to measure real-time glucose concentration, a titrating algorithm to compute the amount of insulin needed, and an insulin pump delivering a rapid-acting insulin analogue (see Fig. 13.4.9.2.1). Only a few prototypes have been developed. Progress has been hindered by suboptimal accuracy and reliability of CGM devices, the relatively slow absorption of subcutaneously administered ‘rapid’-acting insulin analogues, and the lack of adequate control algorithms. So far, testing has been confined to the clinical setting. However, a concentrated effort promises an accelerated progress towards home testing of closed-loop systems. The research focus centres on systems utilizing subcutaneous glucose sensing and subcutaneous insulin delivery. This approach has the greatest potential for a near-future commercial exploitation, although other approaches utilizing intraperitoneal or intravenous sensing/delivery are, in principle, also feasible.

scholarly journals Closed-loop target-controlled infusion system for propofol guided by bispectral index applied in patients undergoing shoulder arthroscopy in the beach chair position- a randomized controlled trial

2020 ◽  
Author(s):  
Zhao Zhao ◽  
Junjie Li ◽  
Yang Fang ◽  
Luo Nanbo ◽  
Yang Han ◽  
...  
Keyword(s):  
Closed Loop ◽  
Shoulder Arthroscopy ◽  
Controlled Trial ◽  
Maintenance Phase ◽  
Open Loop ◽  
Target Controlled Infusion ◽  
Beach Chair Position ◽  
Significant Difference ◽  
Anesthesia Time ◽  
Beach Chair

Abstract Background To compare the efficacy of anesthetic depth control using closed-loop and open-loop target controlled infusion (TCI) system of propofol guided by BIS in patients undergoing shoulder arthroscopy in the beach chair position (BCP). Methods 120 patients underwent shoulder arthroscopy surgery in the BCP were randomized into two groups, the open-loop (O) group and the closed-loop (C) group. During the maintenance phase, BIS value was used as the feedback variable for TCI system of propofol in both groups. The Global score (GS) and the percentage of adequate anesthesia, the frequency of propofol regulation, and consumption of propofol were calculated. The MMSE scores of the day before and 1 day after surgery, serum GFAP and S100B proteins before anesthesia, after extubation and 1 day after surgery were compared. Results The GS and the proportion of appropriate anesthesia time were better in the group C. The percentage of overshoot time was lower in the group C. The frequency of propofol regulation was observed higher in the group C. Propofol consumption in the group C was significantly lower than that in the group O. The MMSE scores, the GFAP and S100B protein concentrations had no significant difference between the two groups. Conclusion Propofol administration using close-loop TCI system guided by BIS may increase the percentage of adequate anesthesia and shorten the percentage of overshoot time compared with open-loop TCI model in anesthesia maintenance phase in patients undergoing shoulder arthroscopy in the BCP, and do not increase the risk of POCD.

scholarly journals Multisensory Testing Framework for Advanced Driver Assistant Systems Supported by High-Quality 3D Simulation

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8458
Author(s):  
Paweł Jabłoński ◽  
Joanna Iwaniec ◽  
Michał Jabłoński
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Detection Algorithm ◽  
Test System ◽  
Open Loop ◽  
Present System ◽  
High Quality ◽  
System Architectures ◽  
The Real ◽  
Assistant Systems

ADAS and autonomous technologies in vehicles become more and more complex, which increases development time and expenses. This paper presents a new real-time ADAS multisensory validation system, which can speed up the development and implementation processes while lowering its cost. The proposed test system integrates a high-quality 3D CARLA simulator with a real-time-based automation platform. We present system experimental verifications on several types of sensors and testing system architectures. The first, open-loop experiment explains the real-time capabilities of the system based on the Mobileye 6 camera sensor detections. The second experiment runs a real-time closed-loop test of a lane-keeping algorithm (LKA) based on the Mobileye 6 line detection. The last experiment presents a simulation of Velodyne VLP-16 lidar, which runs a free space detection algorithm. Simulated lidar output is compared with the real lidar performance. We show that the platform generates reproducible results and allows closed-loop operation which, combined with a real-time collection of event information, promises good scalability toward complex ADAS or autonomous functionalities testing.

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