Noncontact Measurement of Autonomic Nervous System Activities Based on Heart Rate Variability Using Ultra-Wideband Array Radar
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Continuous heart rate measurement using radar is, however, a difficult task because accuracy is compromised by numerous factors, such as the posture and motion of the target person. In this study, we introduce techniques for increasing the accuracy and reliability of the noncontact measurement of heart rate variability. We demonstrate the performance of the proposed techniques by applying them to radar measurement data from a sleeping person, and we also compare its accuracy with electrocardiogram data.
Toward Magnetosomes for Breast Cancer Theranostics
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Our results show that biogenic magnetosomes can increase relative permittivity contrast between 9-25% in the microwave frequency range from 1-10 GHz.
Hierarchical Sensor Fusion for Micro-Gestures Recognition with Pressure Sensor Array and Radar
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Then, a robust wrapper method is applied on the features from both sensors to search the optimal combination. Subsequently, two hierarchical approaches where one sensor acts as ‛enhancer‚ of the other are explored. In the first case, scores from Doppler radar related to the confidence level of its classifier and the prediction label corresponding to the posterior probabilities are utilized to maximize the static hand gestures classification performance by hierarchical combination with PSA data. In the second case, the PSA acts as an ‛Enhancer‚ for radar to improve the dynamic gesture recognition. In this regard, different weights of the ‛Enhancer‚ sensor in the fusion process have been evaluated and compared in terms of classification accuracy. A realistic cross-validation method is chosen to test one unknown participant with the model trained by data from others, demonstrating that this hierarchical fusion approach for static and dynamic gestures yields approximately 16.7% improvement in classification accuracy in the best cases.
Using Dielectric Properties of Solid Fraction and Water Content to Characterize Tissues at Different Health and Age Conditions
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DPs of any healthy tissue can be described by DPs of its solid fraction and water content values. The observed DPs of a tissue change with the level of tissue’s water content (increase or decrease) according to the condition of the tissue (i.e., pathology and age). For the existing study, DPs of solid fraction and water content of 19 different tissues from 61 pigs at different ages were measured and used to generate DPs of those tissues under different conditions using a simple mathematical model. The dry-weighing method was used to determine the water content of tissues and DPs of their solid fractions were measured. Then, DPs of those tissues were generated using the proposed method and found to be in a good agreement with some previously published data as well as with the measured data in this study. This study confirms the potential of using DPs of the solid fraction and water content to calculate DPs of tissues at any age or pathology.
Effect of Dehydration on Dielectric Measurements of Biological Tissue as Function of Time
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Additionally, it proposes a dehydration mitigating technique. The dielectric properties of porcine liver samples were measured during a 35 minute measurement interval at different temperatures. A first set of six experiments was conducted in standard laboratory conditions. A second set of two experiments was conducted with a modified measurement setup with reduced air flow. Under standard conditions, relative changes in the dielectric properties up to 9% were observed. With the modified setup, the relative change was halved compared to standard conditions. This reduction indicates that the environmental conditions have a considerable influence and that modifying these conditions extends the stability of the dielectric properties over time. For several applications relying on the difference in dielectric properties between healthy and malignant tissue, an error of 9% in measured data is on the same order as the effects of interest. The expected difference in dielectric contrast could be obscured due to dehydration.
Real-Time Non-Contact Integrated Chipless RF Sensor for Disposable Microfluidic Applications
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The sensor is based on a microstrip line reader with defected ground plane coupled to a chipless microwave resonator tag. Due to the strong coupling between the reader and the tag, the distance between them can be increased up to 45 mm. The high level of sensitivity of the structure makes it suitable for nanolitre volume scale chemical sensing inside the microfluidic channel. The sensor demonstrates a frequency shift of 6 MHz when the volumetric percentage (V%) of glycerol in DI water changes from 70% to 0%. The proposed solution provides the opportunity of integrating the chipless passive tag with the microfluidic channel while the reader is distant from the microfluidic system.
