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Dan Wang

Bio: Dan Wang is an academic researcher from Old Dominion University. The author has contributed to research in topics: Waveform & Transducer. The author has an hindex of 3, co-authored 9 publications receiving 30 citations.

Papers
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Journal ArticleDOI
Dan Wang1, Jiayue Shen1, Lanju Mei1, Shizhi Qian1, Jiang Li1, Zhili Hao1 
TL;DR: In this article, a wearable distributed-deflection sensor in arterial pulse waveform measurement is presented, which consists of a polymer microstructure embedded with an electrolyte-enabled resistive transducer array.
Abstract: This paper presents a performance investigation of a wearable distributed-deflection sensor in arterial pulse waveform measurement Built on a flexible substrate, the sensor entails a polymer microstructure embedded with an electrolyte-enabled resistive transducer array By pressing the sensor against an artery with hold-down pressure exerted by two fingers, the pulse signal from the artery deflects the microstructure and registers as a resistance change by the transducer at the artery site The radial and carotid pulse signals of five subjects are recorded via the sensor Related signal-processing algorithms are written in Matlab to remove motion artifacts from a recorded pulse signal, extract its key tonometric parameters, and calculate the Pulse Wave Velocity (PWV) and radial and carotid Augmentation Index (AI) Whereas the tonometric parameters of the measured radial and carotid pulse waveforms on each subject are consistent with the related findings in the literature, the difference in tonometric parameters among the subjects also reveals physiological significance The measured PWV and radial and carotid AI of the subjects show good agreement with how they should vary with age, gender and hypertension Finally, the effect of the hold-down pressure on a measured pulse signal and the repeatability of the sensor are examined

13 citations

Journal ArticleDOI
TL;DR: The model-based analysis of arterial pulse signals allows tracking changes in arterial wall parameters using a microfluidic-based tactile sensor for at-home monitoring of the cardiovascular system for early detection, timely intervention and treatment assessment of CVD.
Abstract: Arterial wall parameters (i.e., radius and viscoelasticity) are prognostic markers for cardiovascular diseases (CVD), but their current monitoring systems are too complex for home use. Our objective was to investigate whether model-based analysis of arterial pulse signals allows tracking changes in arterial wall parameters using a microfluidic-based tactile sensor. The sensor was used to measure an arterial pulse signal. A data-processing algorithm was utilized to process the measured pulse signal to obtain the radius waveform and its first-order and second-order derivatives, and extract their key features. A dynamic system model of the arterial wall and a hemodynamic model of the blood flow were developed to interpret the extracted key features for estimating arterial wall parameters, with no need of calibration. Changes in arterial wall parameters were introduced to healthy subjects ( $$n=5$$ ) by moderate exercise. The estimated values were compared between pre-exercise and post-exercise for significant difference ( $$p<0.05$$ ). The estimated changes in the radius, elasticity and viscosity were consistent with the findings in the literature (between pre-exercise and 1 min post-exercise: − 11% ± 4%, 55% ± 38% and 28% ± 11% at the radial artery; − 7% ± 3%, 36% ± 28% and 16% ± 8% at the carotid artery). The model-based analysis allows tracking changes in arterial wall parameters using a microfluidic-based tactile sensor. This study shows the potential of developing a solution to at-home monitoring of the cardiovascular system for early detection, timely intervention and treatment assessment of CVD.

4 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the feasibility of amplifying a measured pulse signal by adding a uniform polydimethylsiloxane (PDMS) layer to a Pyrex-based microfluidic tactile sensor.
Abstract: Various flexible tactile sensors based on micro/nano-fabrication technology have been developed to amplify a measured pulse signal for accuracy. Yet, these sensors suffer from complicated configurations and fabrication complexity. This work is aimed to investigate the feasibility of amplifying a measured pulse signal by adding a uniform polydimethylsiloxane (PDMS) layer to a Pyrex-based microfluidic tactile sensor. The amplifying mechanism of the proposed approach is revealed by theories on sensor-artery interaction. The pulse signals at the radial artery (RA) deep under the skin and the superficial temporal artery (STA) near the skin of one subject are measured by the sensor first with no uniform layer and then with a set of uniform layers with different mixing ratios of PDMS and thickness. Arterial parameters: elasticity, viscosity and radius, are estimated from the measured pulse signals. As compared to those measured with no uniform layer, a uniform layer generates a pulse signal at transmural pressure ( $\text{P}_{\text {T}}$ ) near zero, greatly amplifies the measured pulse signal at both arteries, causes a moderate increase in estimated arterial elasticity, and has negligible effect on estimated arterial viscosity and radius. Due to their anatomical difference, pulse signal amplification is attributed to improved pulse transmission at tissue-sensor interface at the RA and alleviated suppression of the true pulse signal at the STA. The effect of overlying tissue and a uniform layer on estimated arterial parameters is further discussed. The proposed solution offers a low-cost solution to acquiring an amplified pulse signal at $\text{P}_{\text {T}}$ near zero for CV health assessment.

3 citations

Proceedings ArticleDOI
21 Feb 2016
TL;DR: The limited amount of data collected here demonstrates the feasibility of using this flexible polyethylene terephthalate (PET) based wearable sensor as a wearable health monitoring device.
Abstract: In light of the need of health monitoring, the paper presents a flexible polyethylene terephthalate (PET)-based wearable sensor for arterial pulse waveform measurement. The sensor encompasses a polydimethylsiloxane (PDMS) microstructure embedded with an electrolyte-enabled 5×1 transducer array, which spans 6mm and has a spatial resolution of 1.5mm. A pulse signal exerts a deflection on the microstructure and is recorded as a resistance change by a transducer at the site of the pulse. An untrained individual can easily align the sensor on a targeted artery with a negligible margin and then acquire the arterial pulse waveform continuously and non-invasively. This sensor is fabricated using microfluidics technology and thus features low cost for mass production. The sensor is hand-held on an artery and records its pulse signal for a 10s period, which bears baseline drift, due to the respiration and the motion artifact. Discrete Meyer Wavelet Transform (DMWT) and Cubic Spline Estimation (CSE) are employed to remove baseline drift in a pulse signal. The pulse waveform is expressed in terms of the sensor deflection as a function of time. Carotid arterial pulse waveforms are measured by the sensor on three subjects at rest and on two subjects post-exercise. Additionally, radial arterial waveforms are measured on one subject at rest. The measured pulse pattern change of the two subjects between at rest and post-exercise is consistent with the literature. As the pulse transmits from central (carotid) to peripheral (radial) for one subject, the ratio of amplitude of main peak to amplitude of dicrotic wave goes up and the up-stroke time becomes shorter. This is consistent with the related observations in the literature. Thus, the limited amount of data collected here demonstrates the feasibility of using the sensor as a wearable health monitoring device.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: This paper enumerates all major local PWV measurement methods while pinpointing their salient methodological considerations and emphasizing the necessity of global standardization.
Abstract: Local pulse wave velocity (PWV) is evolving as one of the important determinants of arterial hemodynamics, localized vessel stiffening associated with several pathologies, and a host of other cardiovascular events. Although PWV was introduced over a century ago, only in recent decades, due to various technological advancements, has emphasis been directed toward its measurement from a single arterial section or from piecewise segments of a target arterial section. This emerging worldwide trend in the exploration of instrumental solutions for local PWV measurement has produced several invasive and noninvasive methods. As of yet, however, a univocal opinion on the ideal measurement method has not emerged. Neither have there been extensive comparative studies on the accuracy of the available methods. Recognizing this reality, makes apparent the need to establish guideline-recommended standards for the measurement methods and reference values, without which clinical application cannot be pursued. This paper enumerates all major local PWV measurement methods while pinpointing their salient methodological considerations and emphasizing the necessity of global standardization. Further, a summary of the advancements in measuring modalities and clinical applications is provided. Additionally, a detailed discussion on the minimally explored concept of incremental local PWV is presented along with suggestions of future research questions.

88 citations

Journal ArticleDOI
TL;DR: Younger aortas can expand 5 times more than older ones as fluid pumps through them, a finding that could help to design more successful aortic prostheses.
Abstract: Younger aortas can expand 5 times more than older ones as fluid pumps through them, a finding that could help to design more successful aortic prostheses.

38 citations

Journal ArticleDOI
TL;DR: A BP estimation method based on the physical model of wrist skin tissues and pulse wave velocity and photoplethysmography (PPG) sensor and strain gauge is proposed, which is useful for individuals requiring continuous BP monitoring.
Abstract: Blood pressure (BP) is a crucial indicator of cardiac health and vascular status. This study explores the relationship between radial artery BP and wrist skin strain. A BP estimation method based on the physical model of wrist skin tissues and pulse wave velocity (PWV) is proposed. A photoplethysmography (PPG) sensor and strain gauge are used in this method. The developed strain-based pulse wave sensor consists of a pressing force sensor, which ensures consistent pressing force, and a strain gauge, which measures the cardiac pulsation on the wrist skin. These features enable long-term BP monitoring without incurring the limb compression caused by a cuff. Thus, this method is useful for individuals requiring continuous BP monitoring. In this study, the BP of each participant was measured in three modes (before, during, and after exercise), and the data were compared using a clinically validated sphygmomanometer. The percentage errors of diastolic and systolic BP readings were, respectively, 4.74% and 4.49% before exercise, 6.38% and 6.10% during exercise, and 5.98% and 4.81% after a rest. The errors were compared with a clinically validated sphygmomanometer.

36 citations

Journal ArticleDOI
TL;DR: A scoping review of the studies published from 2001 to 2017 that focused on wearable sensor technology and a framework to summarize the research topics is proposed, considering the gaps between current HF/E studies of wearables and the available resources.
Abstract: Humans are an important component of human-machine systems. A better understanding of the role and the status of humans can facilitate and improve the overall human-machine system performance, as well as ensure the well-being of humans. In human factors and ergonomics (HF/E), conventional methods of human performance evaluation usually require the efforts of trained personnel for data collection, data analysis, and the explanation of results. There is an emerging need for a novel and cost-efficient method of assessing human work and status in various systems. The development of wearable technologies has improved the potential for developing a smarter and automatic solution to performing relevant evaluations. In this paper, the authors conduct a scoping review of the studies published from 2001 to 2017 that focused on wearable sensor technology and propose a framework to summarize the research topics. The main steps in the framework include data collection, data processing, and system feedback. Specifically, considering the gaps between current HF/E studies of wearables and the available resources, the authors conducted a detailed review of the application of wearables in HF/E human work evaluation. The opportunities and challenges of introducing wearable sensors into HF/E evaluation are discussed.

36 citations