| 1. |
- Akgun, OmerCan, et al.
(författare)
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High-level energy estimation in the sub-VT domain: simulation and measurement of a cardiac event detector
- 2012
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - 1932-4545. ; 6:1, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a flow that is suitable to estimate energy dissipation of digital standard-cell based designs which are determined to be operated in the sub-threshold regime. The flow is applicable on gate-level netlists, where back-annotated toggle information is used to find the minimum energy operation point, corresponding maximum clock frequency, as well as the dissipated energy per clock cycle. The application of the model is demonstrated by exploring the energy efficiency of pipelining, retiming and register balancing. Simulation results, which are obtained during a fraction of SPICE simulation time, are validated by measurements on a wavelet based cardiac event detector that was fabricated in 65 nm low-leakage high-threshold technology. The mean of the absolute modeling error is calculated as 5.2 %, with a standard deviation of 6.6% over the measurement points. The cardiac event detector dissipates 0.88 pJ/sample at a supply voltage of 320mV.
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| 2. |
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| 3. |
- Buist, Mirka, et al.
(författare)
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Development and Validation of a Wearable Device to Provide Rich Somatosensory Stimulation for Rehabilitation After Sensorimotor Impairment
- 2023
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1932-4545 .- 1940-9990. ; 17:3, s. 547-557
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Tidskriftsartikel (refereegranskat)abstract
- Training sensory discrimination of the skin has the potential to reduce chronic pain due to sensorimotor impairments and increase sensorimotor function. Currently, there is no such device that can systematically provide rich skin stimulation suitable for a training protocol for individuals with amputation or major sensory impairment. This study describes the development and validation of a non-invasive wearable device meant to repeatedly and safely deliver somatosensory stimulations. The development was guided by a structured design control process to ensure the verifiability and validity of the design outcomes. Two sub-systems were designed: 1) a tactile display for touch and vibration sensations, and 2) a set of bands for sliding, pressure, and strain sensations. The device was designed with a versatile structure that allows for its application on different body parts. We designed a device-paired interactive computer program to enable structured sensory training sessions. Validation was performed with 11 individuals with intact limbs whose upper arm tactile sensitivity was measured over 5 training sessions. Tactile discrimination and perception threshold were measured using the standard 2-point discrimination and Semmes-Weinstein monofilament tests, respectively. The results of the monofilament test showed a significant improvement (p = 0.011), but the improvement was not significant for the 2-point discrimination test(p = 0.141). These promising results confirm the potential of the proposed training to increase the sensory acuity in the upper arms of individuals with intact limbs. Further studies will be conducted to determine how to transfer the findings of this work to improve the pain and/or functional rehabilitation in individuals with sensorimotor impairments.
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| 4. |
- Buist, Mirka, et al.
(författare)
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Development and Validation of a Wearable Device to Provide Rich Somatosensory Stimulation for Rehabilitation After Sensorimotor Impairment
- 2023
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Ingår i: Ieee Transactions on Biomedical Circuits and Systems. - 1932-4545. ; 17:3, s. 547-557
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Tidskriftsartikel (refereegranskat)abstract
- Training sensory discrimination of the skin has the potential to reduce chronic pain due to sensorimotor impairments and increase sensorimotor function. Currently, there is no such device that can systematically provide rich skin stimulation suitable for a training protocol for individuals with amputation or major sensory impairment. This study describes the development and validation of a non-invasive wearable device meant to repeatedly and safely deliver somatosensory stimulations. The development was guided by a structured design control process to ensure the verifiability and validity of the design outcomes. Two sub-systems were designed: 1) a tactile display for touch and vibration sensations, and 2) a set of bands for sliding, pressure, and strain sensations. The device was designed with a versatile structure that allows for its application on different body parts. We designed a device-paired interactive computer program to enable structured sensory training sessions. Validation was performed with 11 individuals with intact limbs whose upper arm tactile sensitivity was measured over 5 training sessions. Tactile discrimination and perception threshold were measured using the standard 2-point discrimination and Semmes-Weinstein monofilament tests, respectively. The results of the monofilament test showed a significant improvement (p = 0.011), but the improvement was not significant for the 2-point discrimination test(p = 0.141). These promising results confirm the potential of the proposed training to increase the sensory acuity in the upper arms of individuals with intact limbs. Further studies will be conducted to determine how to transfer the findings of this work to improve the pain and/or functional rehabilitation in individuals with sensorimotor impairments.
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| 5. |
- Chakrabartty, Shantanu, et al.
(författare)
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Guest Editorial
- 2011
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - 1932-4545. ; 5:2, s. 101-102
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Dheman, K., et al.
(författare)
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Wireless, Artefact Aware Impedance Sensor Node for Continuous Bio-Impedance Monitoring
- 2020
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - : Institute of Electrical and Electronics Engineers Inc.. - 1932-4545 .- 1940-9990. ; 14:5, s. 1122-1134
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Tidskriftsartikel (refereegranskat)abstract
- Body bio-impedance is a unique parameter to monitor changes in body composition non-invasively. Continuous measurement of bio-impedance can track changes in body fluid content and cell mass and has widespread applications for physiological monitoring. State-of-the-art implementation of bio-impedance sensor devices is still limited for continuous use, in part, due to artefacts arising at the skin-electrode (SE) interface. Artefacts at the SE interface may arise due to various factors such as motion, applied pressure on the electrode surface, changes in ambient conditions or gradual drying of electrodes. This paper presents a novel bio-impedance sensor node that includes an artefact aware method for bio-impedance measurement. The sensor node enables autonomous and continuous measurement of bio-impedance and SE contact impedance at ten frequencies between 10 kHz to 100 kHz to detect artefacts at the SE interface. Experimental evaluation with SE contact impedance models using passive 2R1C electronic circuits and also with non-invasive in vivo measurements of SE contact impedance demonstrated high accuracy (with maximum error less than 1.5%) and precision of 0.6 ω. The ability to detect artefacts caused by motion, vertically applied pressure and skin temperature changes was analysed in proof of concept experiments. Low power sensor node design achieved with 50mW in active mode and only 143 μW in sleep mode estimated a battery life of 90 days with a 250 mAh battery and duty-cycling impedance measurements every 60 seconds. Our method for artefact aware bio-impedance sensing is a step towards autonomous and unobtrusive continuous bio-impedance measurement for health monitoring at-home or in clinical environments. © 2007-2012 IEEE.
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| 7. |
- Fernández Schrunder, Alejandro, 1993-, et al.
(författare)
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A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass ΔΣ ADC
- 2024
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1932-4545 .- 1940-9990. ; , s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a low-noise bioimpedance (bio-Z) spectroscopy interface for electrical impedance myography (EIM) over the 1 kHz to 2 MHz frequency range. The proposed interface employs a sinusoidal signal generator based on direct-digital-synthesis (DDS) to improve the accuracy of the bio-Z reading, and a quadrature low-intermediate frequency (IF) readout to achieve a good noise-to-power efficiency and the required data throughput to detect muscle contractions. The readout is able to measure baseline and time-varying bio-Z by employing robust and power-efficient low-gain IAs and sixth-order single-bit bandpass (BP) ΔΣ ADCs. The proposed bio-Z spectroscopy interface is implemented in a 180 nm CMOS process, consumes 344.3 - 479.3 μ W, and occupies 5.4 mm 2 area. Measurement results show 0.7 mΩ/√Hz sensitivity at 15.625 kHz, 105.8 dB SNR within 4 Hz bandwidth, and a 146.5 dB figure-of-merit. Additionally, recording of EIM in time and frequency domain during contractions of the bicep brachii muscle demonstrates the potential of the proposed bio-Z interface for wearable EIM systems.
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| 8. |
- Huang, Jiayu, et al.
(författare)
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A Reconfigurable Near-Sensor Processor for Anomaly Detection in Limb Prostheses
- 2024
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1932-4545 .- 1940-9990. ; , s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a reconfigurable near-sensor anomaly detection processor to real-time monitor the potential anomalous behaviors of amputees with limb prostheses. The processor is low-power, low-latency, and suitable for equipment on the prostheses and comprises a reconfigurable Variational Autoencoder (VAE), a scalable Self-Organizing Map (SOM) Array, and a window-size-adjustable Markov Chain, which can implement an integrated miniaturized anomaly detection system. With the reconfigurable VAE, the proposed processor can support up to 64 sensor sampling channels programmable by global configuration, which can meet the anomaly detection requirements in different scenarios. A scalable SOM array allows for the selection of different sizes based on the complexity of the data. Unlike traditional time accumulation-based anomaly detection methods, the Markov Chain is utilized to detect time-series-based anomalous data. The processor is designed and fabricated in a UMC 40-nm LP technology with a core area of 1.49 mm2 and a power consumption of 1.81 mW. It achieves real-time detection performance with 0.933 average F1 Score for the FSP dataset within 24.22 s, and 0.956 average F1 Score for the SFDLA-12 dataset within 30.48 s, respectively. The energy dissipation of detection for each input feature is 43.84 nJ with the FSP dataset, and 55.17 nJ with the SFDLA-12 dataset. Compared with ARM Cortex-M4 and ARM Cortex-M33 microcontrollers, the processor achieves energy and area efficiency improvements ranging from 257×, 193× and 11×, 8×, respectively. IEEE
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| 9. |
- Ivanisevic, Nikola, et al.
(författare)
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Impedance Spectroscopy Based on Linear System Identification
- 2019
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - : IEEE. - 1932-4545 .- 1940-9990. ; 13:2, s. 396-402
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Tidskriftsartikel (refereegranskat)abstract
- Impedance spectroscopy is a commonly used mea-surement technique for electrical characterization of a sample-under-test over a wide frequency range. Most measurementmethods employ a sine wave excitation generator, which implies apoint-by-point frequency sweep and a complex readout architec-ture. This paper presents a fast, wide-band, measurement methodfor impedance spectroscopy based on linear system identification.The main advantage of the proposed method is the low hardwarecomplexity, which consists of a 3-level pulse waveform, aninverting voltage amplifier and a general purpose ADC. A proof-of-concept prototype, which is implemented with off-the-shelfcomponents, achieves an estimation fit of approximately 96%.The prototype operation is validated electrically using knownRC component values and tested in real application conditions.
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| 10. |
- Mastinu, Enzo, 1987, et al.
(författare)
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Embedded System for Prosthetic Control Using Implanted Neuromuscular Interfaces Accessed Via an Osseointegrated Implant
- 2017
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Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - 1940-9990 .- 1932-4545. ; 11:4, s. 867-877
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Tidskriftsartikel (refereegranskat)abstract
- Despite the technological progress in robotics achieved in the last decades, prosthetic limbs still lack functionality, reliability, and comfort. Recently, an implanted neuromusculoskeletal interface built upon osseointegration was developed and tested in humans, namely the Osseointegrated Human-Machine Gateway. Here, we present an embedded system to exploit the advantages of this technology. Our artificial limb controller allows for bioelectric signals acquisition, processing, decoding of motor intent, prosthetic control, and sensory feedback. It includes a neurostimulator to provide direct neural feedback based on sensory information. The system was validated using real-time tasks characterization, power consumption evaluation, and myoelectric pattern recognition performance. Functionality was proven in a first pilot patient from whom results of daily usage were obtained. The system was designed to be reliably used in activities of daily living, as well as a research platform to monitor prosthesis usage and training, machine-learning-based control algorithms, and neural stimulation paradigms.
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