Non-Contact Detection of Vital Signs Based on Improved Adaptive EEMD Algorithm (July 2022)

Non-contact vital sign detection technology has brought a more comfortable experience to the detection process of human respiratory and heartbeat signals. Ensemble empirical mode decomposition (EEMD) is a noise-assisted adaptive data analysis method which can be used to decompose the echo data of frequency modulated continuous wave (FMCW) radar and extract the heartbeat and respiratory signals. The key of EEMD is to add Gaussian white noise into the signal to overcome the mode aliasing problem caused by original empirical mode decomposition (EMD). Based on the characteristics of clutter and noise distribution in public places, this paper proposed a static clutter filtering method for eliminating ambient clutter and an improved EEMD method based on stable alpha noise distribution. The symmetrical alpha stable distribution is used to replace Gaussian distribution, and the improved EEMD is used for the separation of respiratory and heartbeat signals. The experimental results show that the static clutter filtering technology can effectively filter the surrounding static clutter and highlight the periodic moving targets. Within the detection range of 0.5 m similar to 2.5 m, the improved EEMD method can better distinguish the heartbeat, respiration, and their harmonics, and accurately estimate the heart rate

Substrateless Packaging for a D-Band MMIC Based on a Waveguide with a Glide-Symmetric EBG Hole Configuration

This paper presents a novel substrateless packaging solution for the D-band active e mixer MMIC module, using a waveguide line with a glide-symmetric periodic electromagnetic bandgap (EBG) hole configuration. The proposed packaging concept has the benefit of being able to control signal propagation behavior by using a cost-effective EBG hole configuration for millimeter-wave- and terahertz (THz)-frequency-band applications. Moreover, the mixer MMIC is connected to the proposed hollow rectangular waveguide line via a novel wire-bond wideband transition without using any intermediate substrate. A simple periodical nail structure is utilized to suppress the unwanted modes in the transition. Additionally, the presented solution does not impose any limitations on the chip\u27s dimensions or shape. The packaged mixer module shows a return loss lower than 10 dB for LO (70-85 GHz) and RF (150-170 GHz) ports, achieving a better performance than that of traditional waveguide transitions. The module could be used as a transmitter or receiver, and the conversion loss shows good agreement in multiple samples. The proposed packaging solution has the advantages of satisfactory frequency performance, broadband adaptability, low production costs, and excellent repeatability for millimeter-wave- and THz-band systems, which would facilitate the commercialization of millimeter-wave and THz products

A Real-time Target Detection Algorithm for Panorama Infrared Search and Track System

AbstractWith regard to target detection in high resolution panorama images attained by circumferential scan Infrared Search and Tracking system, a rough-to-meticulous real-time target detection algorithm is proposed based on analysis of characteristics of targets and background. In the rough detection phase, it attains initial high rate target detection by quick real-time algorithm, based on the gray high frequency and movement characteristics of the target in the whole panorama image. In the meticulous detection phase, focusing on the detected suspected target sliced images, it has further delicate detection and recognition on the basis of targets’ characteristics to exclude those false jamming. The detection result of the test images shows, the algorithm enables stable detection with low-rate false alarm for distant dim small targets, and has been applied to the development of engineering sample of the Panorama Infrared Search and Tracking system

MSS-DepthNet: Depth Prediction with Multi-Step Spiking Neural Network

Event cameras are considered to have great potential for computer vision and robotics applications because of their high temporal resolution and low power consumption characteristics. However, the event stream output from event cameras has asynchronous, sparse characteristics that existing computer vision algorithms cannot handle. Spiking neural network is a novel event-based computational paradigm that is considered to be well suited for processing event camera tasks. However, direct training of deep SNNs suffers from degradation problems. This work addresses these problems by proposing a spiking neural network architecture with a novel residual block designed and multi-dimension attention modules combined, focusing on the problem of depth prediction. In addition, a novel event stream representation method is explicitly proposed for SNNs. This model outperforms previous ANN networks of the same size on the MVSEC dataset and shows great computational efficiency

Vibration control of a tunnel boring machine using adaptive magnetorheological damper

With a large number of tunnel boring machines (TBM) being used in various tunnel constructions, the vibration problem under complex geological conditions have become increasingly prominent. In order to solve the problem, this article investigates the application of an adaptive magnetorheological (MR) damper on the vibration reduction of a TBM. The MR damper could reduce the horizontal vibration of the TBM system and adjust its dragging force on the propulsive system under different geological conditions. The MR damper can also provide large enough damping force even under a small amplitude vibration, which is required by TBM. In this paper, an MR damper was designed, prototyped and its properties were tested by an MTS system, including its current-dependency, amplitude-dependency and frequency-dependency features. A scaled TBM system incorporated with the MR damper was built to evaluate the vibration reduction effectiveness of the MR damper on the TBM system. The experimental test results demonstrate that the displacement and the acceleration amplitudes of the TMB vibration could be reduced by 52.14% and 53.31%, respectively

Pharmacokinetics of ligustrazine ethosome patch in rats and anti-myocardial ischemia and anti-ischemic reperfusion injury effect

The objective of this study was to investigate the pharmacokinetics of the ligustrazine ethosome patch and antimyocardial ischemia and anti-ischemic reperfusion injury effect. Male Sprague Dawley rats were divided randomly into 3 groups: Group A (intragastric ligustrazine), Group B (transdermal ligustrazine ethosome patch), and Group C (conventional transdermal ligustrazine patch). After treatment, samples of blood and of various tissues such as heart, liver, spleen, lung, kidney, brain, and muscle samples were taken at different time points. Drug concentration was measured with HPLC, and the drug concentration–time curve was plotted. Pharmacokinetic software 3p97 was applied to calculate pharmacokinetic parameters and the area under the drug concentration–time curve (AUC) in various tissues. The rat model of acute myocardial ischemia was constructed with intravenous injection of pituitrin and the model of myocardial ischemia-perfusion injury was constructed by tying off the left anterior descending coronary artery of rats to observe the effect of ligustrazine ethosome patches on ischemic myocardium and ischemia-reperfusion injury. Results showed that AUC was highest in the transdermal drug delivery group of ligustrazine ethosome patch. There were significant differences in whole blood viscosity, plasma viscosity, hematocrit, red blood cell aggregation index, and deformation index between ligustrazine the ethosome patch group and ischemic control group (P < 0.01). Moreover, ligustrazine ethosome patches could reduce the scope of myocardial infarction induced by long-term ischemia. Ligustrazine ethosome patches have a sustained-release property. They can maintain stable and sustained blood drug concentration, increase bioavailability, and reduce administration times. The drug patch can decrease hemorheological indices of myocardial ischemia in rats, as well as protect acute ischemic myocardium and ischemia-reperfusion injured myocardium

Alteration of Innate Immunity by Donor IL-6 Deficiency in a Presensitized Heart Transplant Model

Engraftment of IL-6 deficient donor into wild-type recipient could significantly improve allograft survival through T cell lineage particularly regulatory T cells (Tregs) in non-sensitized transplant host. However, its effect on innate immune responses remains uncertain. Our data revealed that donor IL-6 deficiency significantly increased infiltration of two subsets of MDSCs (CD11b+Gr1+myeloid-derived suppressor cells), CD11b+Gr1-low and CD11b+Gr1-int with strong immunosuppression activity in the transplanted graft. It resulted in a dramatic increase of CD11b+Gr1-low frequency and a significant decrease of the frequency of CD11b+Gr1-high and CD4-CD8-NK1.1+ cells in the recipient’s spleen. Unexpectedly, donor IL-6 deficiency could not significantly reduce macrophage frequency irrespective of in the host’s spleen or graft. Taken together, suppression of innate immune effector cells and enhanced activity of regulatory MDSCs contributed to tolerance induction by blockade of IL-6 signaling pathway. The unveiled novel mechanism of targeting IL-6 might shed light on clinical therapeutic application in preventing accelerated allograft rejection for those pre-sensitized transplant recipients