Accurate and Contactless Vital Sign Detection in Short Time Window with 24 GHz Doppler Radar

Breathing and heartbeat are critical vital signs which reflect the health status of human beings. Aiming to accurately measure the vital sign in short time window, a novel signal processing method for Doppler radar vital sign detection is proposed. Firstly, a two-step I/Q mismatch correction method which, respectively, estimates the time invariant phase imbalance and gain ratio of I/Q channels in the calibration step and the direct-current offsets during normal operation has been proposed. By decreasing the number of estimation parameters from 5 to 2, the parameters can be effectively estimated with data distributed over shorter arc lengths. Then, to solve the discontinuity occurred in arctangent demodulation, the displacement information of chest movement is extracted from the calibrated I/Q signals by extended differentiate and cross multiply algorithm. Finally, instead of Fourier transform-based methods which require long time windows to guarantee sufficient frequency resolution, the optimal parameters of respiration and heartbeat are found by the intelligent search of the differential evolution algorithm. The experimental results show that the proposed method can accurately measure respiratory rate and heartbeat rate with a short time window. For the 8 s time window, the mean absolute errors of respiration and heartbeat were 0.52 bpm and 0.79 bpm, respectively, demonstrating its promise in real-time applications.

Download Full-text

231 A SHORT TIME WINDOW TO PROFIT FROM IL-4 PLUS IL-10 ADDITION TO PROTECT CARTILAGE FROM BLOOD-INDUCED DAMAGE IN VITRO

Osteoarthritis and Cartilage ◽

10.1016/s1063-4584(11)60258-6 ◽

2011 ◽

Vol 19 ◽

pp. S113

Author(s):

M.E. van Meegeren ◽

N.W. Jansen ◽

G. Roosendaal ◽

S.C. Mastbergen ◽

F.P. Lafeber

Keyword(s):

Time Window ◽

Short Time Window ◽

Short Time

Download Full-text

383. Feasibility of Specimen Self-collection in Young Children Undergoing SARS-CoV-2 Surveillance for In-person Learning

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.584 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S293-S293

Author(s):

Jonathan Altamirano ◽

Grace Tam ◽

Marcela Lopez ◽

India Robinson ◽

Leanne Chun ◽

...

Keyword(s):

Young Children ◽

Time Window ◽

School Administrators ◽

Error Rates ◽

Independent Observer ◽

Specimen Collection ◽

Timing Data ◽

Short Time Window ◽

Short Time ◽

Over Time

Abstract Background While pediatric cases of COVID-19 are at low risk for adverse events, schoolchildren should be considered for surveillance as they can become infected at school and serve as sources of household or community transmission. Our team assessed the feasibility of young children self-collecting SARS-CoV-2 samples for surveillance testing in an educational setting. Methods Students at a K-8 school were tested weekly for SARS-CoV-2 from September 2020 - June 2021. Error rates were collected from September 2020 - January 2021. Clinical staff provided all students with instructions for anterior nares specimen self-collection and then observed them to ensure proper technique. Instructions included holding the sterile swab while making sure not to touch the tip, inserting the swab into their nostril until they start to feel resistance, and rubbing the swab in four circles before repeating the process in their other nostril. An independent observer timed random sample self-collections from April - June 2021. Results 2,590 samples were collected from 209 students during the study period when data on error rates were collected. Errors occurred in 3.3% of all student encounters (n=87). Error rates over time are shown in Figure 1, with the highest rate occurring on the first day of testing (n=20/197, 10.2%) and the lowest in January 2021 (n=1/202, 0.5%). 2,574 visits for sample self-collection occurred during the study period when independent timing data was collected (April - June 2021). Of those visits, 7.5% (n=193) were timed. The average duration of each visit was 70 seconds. Figure 1. Swab Error Rates Over Time Conclusion Pediatric self-collected lower nasal swabs are a viable and easily tolerated specimen collection method for SARS-CoV-2 surveillance in school settings, as evidenced by the low error rate and short time window of sample self-collection during testing. School administrators should expect errors to drop quickly after implementing testing. Disclosures All Authors: No reported disclosures

Download Full-text

Dual origin of the floor plate in the avian embryo

Development ◽

10.1242/dev.129.20.4785 ◽

2002 ◽

Vol 129 (20) ◽

pp. 4785-4796 ◽

Cited By ~ 6

Author(s):

Jean-Baptiste Charrier ◽

Françoise Lapointe ◽

Nicole M. Le Douarin ◽

Marie-Aimée Teillet

Keyword(s):

Time Window ◽

Gene Expression Pattern ◽

Floor Plate ◽

Avian Embryo ◽

Plate Formation ◽

Unknown Factor ◽

Short Time Window ◽

Neural Ectoderm ◽

Dual Origin ◽

Short Time

Molecular analysis carried out on quail-chick chimeras, in which quail Hensen’s node was substituted for its chick counterpart at the five- to six-somite stage (ss), showed that the floor plate of the avian neural tube is composed of distinct areas: (1) a median one (medial floor plate or MFP) derived from Hensen’s node and characterised by the same gene expression pattern as the node cells (i.e. expression of HNF3β and Shh to the exclusion of genes early expressed in the neural ectoderm such as CSox1); and (2) lateral regions that are differentiated from the neuralised ectoderm (CSox1 positive) and form the lateral floor plate (LFP). LFP cells are induced by the MFP to express HNF3β transiently, Shh continuously and other floor-plate characteristic genes such as Netrin. In contrast to MFP cells, LFP cells also express neural markers such as Nkx2.2 and Sim1. This pattern of avian floor-plate development presents some similarities to floor-plate formation in zebrafish embryos. We also demonstrate that, although MFP and LFP have different embryonic origins in normal development, one can experimentally obtain a complete floor plate in the neural epithelium by the inductive action of either a notochord or a MFP. The competence of the neuroepithelium to respond to notochord or MFP signals is restricted to a short time window, as only the posterior-most region of the neural plate of embryos younger than 15 ss is able to differentiate a complete floor plate comprising MFP and LFP. Moreover, MFP differentiation requires between 4 and 5 days of exposure to the inducing tissues. Under the same conditions LFP and SHH-producing cells only induce LFP-type cells. These results show that the capacity to induce a complete floor plate is restricted to node-derived tissues and probably involves a still unknown factor that is not SHH, the latter being able to induce only LFP characteristics in neuralised epithelium.

Download Full-text

Comments on “Respiration Rate Measurement Under 1-D Body Motion Using Single Continuous-Wave Doppler Radar Vital Sign Detection System”

IEEE Transactions on Microwave Theory and Techniques ◽

10.1109/tmtt.2019.2916415 ◽

2019 ◽

Vol 67 (7) ◽

pp. 2821-2822

Author(s):

Zi-Kai Yang ◽

Xiang-Dong Huang

Keyword(s):

Respiration Rate ◽

Vital Sign ◽

Continuous Wave ◽

Doppler Radar ◽

Detection System ◽

Body Motion ◽

Rate Measurement ◽

Continuous Wave Doppler ◽

Sign Detection ◽

Respiration Rate Measurement

Download Full-text

Distribution of interspike intervals estimated from multiple spike trains observed in a short time window

Physical Review E ◽

10.1103/physreve.83.011910 ◽

2011 ◽

Vol 83 (1) ◽

Cited By ~ 4

Author(s):

Zbyněk Pawlas ◽

Petr Lansky

Keyword(s):

Time Window ◽

Spike Trains ◽

Interspike Intervals ◽

Short Time Window ◽

Short Time

Download Full-text

Vital Sign Detection during Large-Scale and Fast Body Movements Based on an Adaptive Noise Cancellation Algorithm Using a Single Doppler Radar Sensor

Sensors ◽

10.3390/s20154183 ◽

2020 ◽

Vol 20 (15) ◽

pp. 4183 ◽

Cited By ~ 1

Author(s):

Zi-Kai Yang ◽

Heping Shi ◽

Sheng Zhao ◽

Xiang-Dong Huang

Keyword(s):

Vital Sign ◽

Large Scale ◽

Doppler Radar ◽

Noise Cancellation ◽

Home Healthcare ◽

Adaptive Noise Cancellation ◽

Body Movements ◽

Radar Sensor ◽

Sign Detection ◽

Adaptive Noise

The non-contact detection of human vital signs (i.e., respiration rate (RR) and heartbeat rate (HR)) using a continuous-wave (CW) Doppler radar sensor has great potential for intensive care monitoring, home healthcare, etc. However, large-scale and fast random body movement (RBM) has been a bottleneck for vital sign detection using a single CW Doppler radar. To break this dilemma, this study proposed a scheme combining adaptive noise cancellation (ANC) with polynomial fitting, which could retrieve the weak components of both respiration and heartbeat signals that were submerged under serious RBM interference. In addition, the new-type discrete cosine transform (N-DCT) was introduced to improve the detection accuracy. This scheme was first verified using a numerical simulation. Then, experiments utilizing a 10-GHz Doppler radar sensor that was built from general-purpose radio frequency (RF) and communication instruments were also carried out. No extra RF/microwave components and modules were needed, and neither was a printed circuit board nor an integrated-chip design required. The experimental results showed that both the RR and HR could still be extracted during large-scale and fast body movements using only a single Doppler radar sensor because the RBM noises could be greatly eliminated by utilizing the proposed ANC algorithm.

Download Full-text

A New Method for Automated Clearcut Disturbance Detection in Mediterranean Coppice Forests Using Landsat Time Series

Remote Sensing ◽

10.3390/rs12223720 ◽

2020 ◽

Vol 12 (22) ◽

pp. 3720 ◽

Cited By ~ 1

Author(s):

Francesca Giannetti ◽

Raffaello Pegna ◽

Saverio Francini ◽

Ronald E. McRoberts ◽

Davide Travaglini ◽

...

Keyword(s):

Time Series ◽

Sustainable Forest Management ◽

Time Window ◽

Detection Algorithm ◽

Forest Disturbances ◽

Forest Change ◽

Short Time Window ◽

Short Time ◽

Automated Procedures ◽

Disturbance Detection

A Landsat time series has been recognized as a viable source of information for monitoring and assessing forest disturbances and for continuous reporting on forest dynamics. This study focused on developing automated procedures for detecting disturbances in Mediterranean coppice forests which are characterized by rapid regrowth after a cut. Specifically, new methods specific to Mediterranean coppice forests are needed for mapping clearcut disturbances over time and for estimating related indicators in the context of Sustainable Forest Management and Biodiversity International monitoring frameworks. The aim of this work was to develop a new change detection algorithm for mapping clearcut disturbances in Mediterranean coppice forests with Landsat time series (LTS) using a short time window. Accuracy for the new algorithm, characterized as the Two Thresholds Method (TTM), was evaluated using an independent clearcut reference dataset over a temporal period of the 13 years between 2001 and 2013. TTM was also evaluated against two benchmark approaches: (i) LandTrendr, and (ii) the forest loss category of the Global Forest Change Map. Overall Accuracy for LandTrendr and TTM were greater than 0.94. Meanwhile, smaller accuracies were always obtained for the GFC. In particular, Producer’s Accuracy ranged between 0.45 and 0.84 for TTM and between 0.49 and 0.83 for LT, while for the GFC, PA ranged between 0 and 0.38. User’s Accuracy ranged between 0.86 and 0.96 for TTM and between 0.73 and 0.91 for LT, while for the GFC UA ranged between 0.19 and 1.00. Moreover, to illustrate the utility of TTM for mapping clearcut disturbances in Mediterranean coppice forests, we applied TTM to a Landsat scene that covered almost the entirety of the Tuscany region in Italy.

Download Full-text

Parameters of Spike Trains Observed in a Short Time Window

Neural Computation ◽

10.1162/neco.2007.01-07-442 ◽

2008 ◽

Vol 20 (5) ◽

pp. 1325-1343 ◽

Cited By ~ 13

Author(s):

Zbyněk Pawlas ◽

Lev B. Klebanov ◽

Martin Prokop ◽

Petr Lansky

Keyword(s):

Coefficient Of Variation ◽

Point Processes ◽

Interspike Interval ◽

Time Window ◽

Time Windows ◽

Time Interval ◽

Short Time Interval ◽

Target Neuron ◽

Short Time Window ◽

Short Time

We study the estimation of statistical moments of interspike intervals based on observation of spike counts in many independent short time windows. This scenario corresponds to the situation in which a target neuron occurs. It receives information from many neurons and has to respond within a short time interval. The precision of the estimation procedures is examined. As the model for neuronal activity, two examples of stationary point processes are considered: renewal process and doubly stochastic Poisson process. Both moment and maximum likelihood estimators are investigated. Not only the mean but also the coefficient of variation is estimated. In accordance with our expectations, numerical studies confirm that the estimation of mean interspike interval is more reliable than the estimation of coefficient of variation. The error of estimation increases with increasing mean interspike interval, which is equivalent to decreasing the size of window (less events are observed in a window) and with decreasing the number of neurons (lower number of windows).

Download Full-text