MARS
MARS is a repository service of Mason Publishing and the Data and Digital Scholarship Services (DDSS) at the George Mason University Libraries. MARS provides enduring, stable, well-indexed access to a wide range of scholarship from the Mason community, such as Electronic Theses and Dissertations (ETDs), articles, presentations, reports, and creative work. Learn more about publishing, sharing, and preserving research data with the George Mason University Institutional Dataverse, and our other repository services.
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Recent Submissions
A study on the usage of Strain-gauge based tonometry to measure radial and carotid artery pressure waves compared to PPG based IR pulse sensors for use in cuffless blood pressure devices
(2026-05-09) Senthilkumar, Vishvajit; Peixoto, Nathalia
This research evaluates the efficacy of a resistive strain-gauge-based arterial tonometry system utilizing an HX711 high-gain amplifier and 24-bit ADC, benchmarking its performance against a traditional infrared [IR] photoplethysmography [PPG] sensor [MAX30102]. The study focuses on resolving arterial pressure waveforms at the radial and carotid sites to calculate heart rate [BPM] using Peak Detection [PD] and Fast Fourier Transform [FFT] algorithms. Experimental results indicate that both sensors achieved higher accuracy at the carotid site due to superior mechanical coupling and reduced tissue damping, with the HX711 carotid configuration yielding the highest overall accuracy [1.19% error via FFT Closest Peak].
Analysis of the Signal-to-Noise Ratio [SNR] and noise floors reveals a fundamental trade-off: while the strain gauge exhibits a significantly lower baseline noise floor due to its immunity to optical interference, the IR PPG sensor maintains a superior SNR and dynamic range, better capturing the high-magnitude volumetric changes of the arterial pulse. Furthermore, linearity analysis demonstrates that while the IR sensor provides more linearized data, the FFT Closest Peak algorithm consistently outperforms Peak Detection in isolating true physiological signals from motion artifacts. These findings suggest that while strain-gauge tonometry is less susceptible to environmental noise, its current implementation faces limitations in dynamic range relative to PPG-based counterparts. However, the high accuracy of the frequency-domain analysis confirms that strain-gauge systems are viable for advanced hemodynamic applications such as Pulse Wave Velocity [PWV] monitoring.
Development of a Hydrophone Using a Ceramic Piezoelectric Sensor
(2026-05) Barry, Kelly; Peixoto, Nathalia
This paper presents the development and analysis of a piezoelectric hydrophone and signal conditioning circuit. The focus is to understand and compare how this prototype compares to traditional off the shelf hydrophones (namely the Aquarian A5) and provide useful analysis of the limitations of a cost effective sensor. Using a controlled testing environment, the developed hydrophone was able to accurately receive transmitted signals from a transceiver underwater. PSD plots showed an estimated 9 dB increase in SNR for the signal received using the amplifier circuit. Discussion of the benefits and shortcomings of this system provide achievable guidelines for how the developed sensor can be optimized.
Signal properties of amplified speech outdoors
(The 190th meeting of The Acoustical Society of America, 2026-05-12) Kelley, Matthew C.; Cutter, Adam A.; Kelly, Susan; Kidd, Jordan A.; Soldati, Giulia M.; Miklas, Janalyn A.
Phonetics is replete with studies about speech in quiet indoor environments. However, many speech events occur outdoors. Additionally, in the modern era, they are frequently amplified. The present study examines signal properties of amplified speech in an outdoor setting. Four speakers read a subset of the Harvard sentences over a loudspeaker using a wireless handheld microphone in a quiet soccer field outdoors in late summer of 2025 on a sunny day. Recordings for each speaker were taken simultaneously at 4 m, 8 m, and 16 m away from the loudspeaker, in addition to a recording directly from the microphone. Intensity measurements were taken using a sound level meter several times at each distance during each session. Loudspeaker volume was adjusted for each speaker to produce an average intensity of approximately 95 dB measured at 1 m away. The overall intensity drop as distance increases will be measured for each sentence, which is predicted by the inverse-square law to be approximately 6 dB each time the distance doubles. The signal-to-noise ratio will also be estimated for each sentence. These and other quantities will be interpreted in relation to speech intelligibility in outdoor settings.
Alternate Light Assessment of Skin Trauma (AtLAST): Guidelines for Clinical Practice
(2023-11) Scafide, Katherine N.; Ekroos, Rachell A.
The following document provides practice guidelines for using an alternate light source (ALS) to detect and document possible physical trauma during a clinical skin assessment. These guidelines offer recommended standards for forensic clinicians to apply the ALS technology during patient encounters and appropriately interpret observations based on available scientific evidence.
Development of these guidelines included a contextual assessment of patient care practices, organizational resources, and stakeholder input (i.e., forensic clinicians, law enforcement professionals, and prosecuting attorneys) at two forensic nursing departments.1 Data collection included historical data from a forensic nursing department with ten years of clinical experience integrating ALS in medical forensic examinations of soft tissue skin injuries and a forensic nursing department at a separate organization integrating ALS as a new clinical practice. A focused grey literature search for existing standards and practice guidelines on ALS application in the clinical setting assisted in understanding current practices further. Finally, a systematic review and appraisal of peer-reviewed literature provided the scientific evidence base to support the practice recommendations in these guidelines (see Appendix A).
These guidelines address considerations related to the physical clinical environment, equipment, and patient conditions for using ALS in clinical practice to assess for possible soft-tissue skin trauma. The included step-by-step protocol for ALS application in the clinical setting is trauma-informed, patient-centered, and considerate of patient and user safety. These guidelines also include sections introducing the reader to documentation considerations (written and image documentation) of ALS technology use, informed testimony preparation, and education and training requirements.
The Mason Statistician
(2026) Auerbach, Jonathan
A magazine published annually showcasing the capstones completed by the graduates of the Department of Statistics.