Library · Signals, sensing & imaging

What Wearable & Mobile Sensing got wrong, from 40 theses

Summary written by a model from the records below: The records demonstrate that wearable and mobile sensing deployments frequently struggle with sensor placement instability, physiological variability, and user non-compliance. Furthermore, proprietary algorithms, sparse kinematic configurations, and fixed robotic assistance profiles often fail to generalize across diverse operating conditions. These records come from graduate theses, 2021 to 2026, each labeled with its degree where the repository states it, and each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.

40
theses
18
institutions
41
failure records
7
failure modes

Plus 7 problems the authors left open, listed at the end.

Failure modes, by theses reporting them

Select a mode to jump to its records.

Sparse inertial sensing and isolated sensor placements fail to capture complex kinematics and kinetic forces
8
8 theses · 6 institutions · 8 records
Wearability burden, frequent charging, and adherence difficulties undermine continuous tracking
8
8 theses · 5 institutions · 8 records
Physiological and mobile signals suffer from environmental confounders and poor discriminative power
7
7 theses · 6 institutions · 7 records
Sensor displacement and mechanical coupling shifts degrade wearable signal quality
5
5 theses · 3 institutions · 5 records
Fixed thresholds and proprietary vendor algorithms fail to generalize or accurately detect events
5
5 theses · 5 institutions · 5 records
Discrepancies across hardware devices and populations impair cross-subject model transferability
5
5 theses · 5 institutions · 5 records
Fixed biomimetic torque profiles fail to adapt to individual dynamics in wearable robotic assistance
2
2 theses · 1 institutions · 3 records

Sparse inertial sensing and isolated sensor placements fail to capture complex kinematics and kinetic forces

8 theses · 6 institutions

Single-point inertial measurement units and wrist-worn accelerometers lacked the spatial degrees of freedom required to distinguish posture, reconstruct finger movements, or detect dynamic balance perturbations. Kinematic estimation from sparse inertial sensors failed to match goniometer baselines, could not reliably estimate ground reaction forces, and was susceptible to motion artifacts during real-world movement tracking.

Considered and rejected

Considered and rejected: Rejected relying solely on wearable wrist sensors because they failed to capture isolated finger movements and complex full-body kinematics.

Where is the Person in Personalized Medicine? The Missing Expert in Adaptive Neurotechnology · University of Washington · PhD

Considered and rejected

Considered and rejected: Rejected using only total acceleration (accel_total) magnitude for wrist-worn sensors because it could not discriminate between sitting and standing.

Deep Neural Network Representations of Physiological Time-Series Sensor Data for Improved Recognition Performance · Texas State University · PhD

Tried and failed

adding triaxial accelerometry to multimodal sensing applied to sleep wake detection. Outcome: no signal. Reason: wrist accelerometry features did not provide additional discriminative value beyond combined video and PPG

Combining wearables and nearables for patient state analysis · Georgia Tech · PhD

Tried and failed

kinematic inertial sensor estimation applied to ground reaction force estimation. Outcome: worse than baseline. Reason: high stride-by-stride kinematic variability and non-sagittal compensatory movements degraded accuracy relative to direct force sensing

Experimental and Analytical Methods for Understanding User Gait Biomechanics in Response to Soft Ankle Exosuits · Harvard · PhD

Tried and failed

inertial motion capture for joint angle measurement applied to human joint kinematics validation. Outcome: worse than baseline. Reason: inertial sensors failed to agree with baseline goniometer measurements across multiple joints

Integration of Physical and Psychological Human Data into Digital Human Modelling for Manufacturing System Design · Cranfield · PhD

Tried and failed

single-point inertial measurement unit tracking applied to complex exercise motion classification. Outcome: no signal. Reason: single-channel kinematics lacked sufficient spatial degrees of freedom without multi-site bodily strain sensing

Study Of Intelligent Wearables and Adaptive Systems to Measure Physiological and Physical Data for Human-Machine Interfaces · Georgia Tech · PhD

Considered and rejected

Considered and rejected: Rejected calculating stepping kinematics and trunk angular velocity from wearable IMUs in the real world due to sensitivity to motion artifacts and inter-sensor distance estimation errors.

Non-Treadmill Trip Training – Laboratory Efficacy, Validation of Inertial Measurement Units, and Tripping Kinematics in the Real World · Virginia Tech · Doctorate

Considered and rejected

Considered and rejected: Rejected measuring physical activity with simple accelerometers alone in population health studies, recommending wearable devices that incorporate continuous heart-rate monitoring.

Essays on Selection in Health Behaviors · Harvard · PhD

Wearability burden, frequent charging, and adherence difficulties undermine continuous tracking

8 theses · 5 institutions

Multi-device configurations across bilateral limbs and continuous wearable tracking were rejected or failed due to high wearing discomfort, charging demands, and low compliance in cognitively impaired cohorts. Participants frequently deactivated passive mobile sensing streams to conserve battery, while bodily worn sensors were deemed impractical for natural walk-up public scenarios and gesture recognition.

Considered and rejected

Considered and rejected: Rejected bodily worn tracking sensors due to lack of suitability for natural walk-up-and-use public scenarios.

How can people’s spatial behaviour be used to dynamically lay out content on multi-user, interactive screens, and how does this dynamic layout affect people’s spatial behaviour? · Nottingham · PhD

Considered and rejected

Considered and rejected: Rejected multi-device wearable setups (bilateral feet/wrists/sternum) for continuous free-living monitoring due to high wearability burden, reduced patient compliance, and battery charging demands.

Development and evaluation of computational methods for measuring free-living gait and uncovering neuropathology in Parkinson’s disease · Boston University · PhD

Considered and rejected

Considered and rejected: Wearable sensors for hand gesture recognition were rejected because they are expensive, complex, and unnatural.

Human-Interactions with Robotic Cyber-Physical Systems (CPS) for Facilitating Construction Progress Monitoring · Virginia Tech · Doctorate

Considered and rejected

Considered and rejected: Excluded wearable sleep trackers in favor of under-the-mattress sensors to avoid data loss from short battery life, frequent charging, and adherence issues in cognitively impaired populations.

From behavioural patterns to rain barriers: representation learning for ageing and dementia · Imperial · PhD

Considered and rejected

Considered and rejected: Rejected wearable multi-device setups (e.g., S-Smart pocket smartphone + wrist IMU + foot IMU) due to daily living inconvenience

Smartwatch-based semantic learning of elements of human behaviour · Oxford · PhD

Considered and rejected

Considered and rejected: Rejected using smartphone passive sensing streams (e.g., Bluetooth device counts) due to participant deactivations for battery conservation causing excessive missingness.

Forecasting depressive symptom deterioration using wearable sensor data and LSTM models: a longitudinal analysis from the RADAR-MDD Study · Nottingham · Doctorate

Tried and failed

wearable activity tracking applied to cognitively impaired older adults. Reason: poor user adoption, adherence, and tolerance leading to non-compliance

Monitoring the effects of traumatic brain injury in older adults using a remote home monitoring system · Imperial · Doctorate

Considered and rejected

Considered and rejected: Rejected wearable devices for continuous tracking due to low patient compliance associated with cognitive impairments

Monitoring behavioural changes in households with dementia using intelligent ambient sensing technologies · Imperial · PhD

Physiological and mobile signals suffer from environmental confounders and poor discriminative power

7 theses · 6 institutions

Ambient temperature caused galvanic skin response runaway and prior exercise disrupted heart rate variability ratios, while peripheral temperature distributions showed wide overlap across affective states. Sensor features failed to correlate with breathing-zone pollutant exposure, could not detect seizures lacking tachycardia, and lacked predictive signal for clinical depression scale scores.

Tried and failed

multimodal physiological stress detection with wearable sensors applied to autonomic tone and stress monitoring. Outcome: unstable. Reason: High ambient temperature caused GSR runaway and prior exercise disrupted HRV LF/HF ratio reliability

A Skin-Like Sternal Patch to Monitor Autonomic Tone During Cognitive Stress and Sympathetic Arousals in Disordered Sleep · Georgia Tech · PhD

Tried and failed

wearable physiological sensors for affective state detection applied to detecting emotional responses to transient events. Outcome: no signal. Reason: sensors failed to reliably isolate heart rate changes triggered by transient unexpected errors

Artificial social constructivism for long term human computer interaction · Imperial · PhD

Tried and failed

heuristic feature normalization without patient baseline applied to physiological regression from wearable sensor features. Outcome: no signal. Reason: external statistics and weight scaling failed to capture individual physiological baseline variability

Towards real-time estimation of decompensation status in acute pathological conditions leveraging wearable technology and machine learning · Georgia Tech · PhD

Considered and rejected

Considered and rejected: Attempting detection of FIA seizures lacking tachycardia, rejected as not sufficiently stereotyped across patients for consumer wearable sensors.

Focal Impaired Awareness Seizure Detection Using a Smartwatch · Johns Hopkins · Master's

Considered and rejected

Considered and rejected: Rejected electromyography (EMG) sensors for obtaining muscle forces due to signal fuzziness and sensitivity to environmental conditions

Efficient and Safe Robot Planning in Human-Robot Collaboration · University at Buffalo · PhD

Tried and failed

gradient boosted trees with automated feature selection applied to depression prediction from smartphone sensing. Outcome: no signal. Reason: passive mobile sensor features lacked detectable predictive signal for depression scale scores

Applying lessons from a critical analysis of machine learning in psychological science : two examples predicting psychological traits and states using voice data · UT Austin · PhD

Tried and failed

predicting environmental exposure from wearable physiological signals applied to personal inhalation exposure estimation. Outcome: no signal. Reason: physiological metrics alone lack sufficient correlation with breathing-zone pollutant concentrations across varied activities

Assessment of Monitoring Strategies for Inhalation Exposure and Occupancy in Office Environments · EPFL · PhD

Sensor displacement and mechanical coupling shifts degrade wearable signal quality

5 theses · 3 institutions

Wearable interface condition changes caused spatial shifts in activation patterns, and fixed proximity thresholds yielded high false negative rates when identifying sensor detachment. Direct skin taping made consistent cross-session sensor placement difficult without trained professionals, tensile transducer stretching caused pressure cancellation, and wrist locations underperformed chest placements.

Tried and failed

single sensor placement optimization for signal quality applied to biosignal decoding across mechanical conditions. Outcome: did not generalise. Reason: Spatial shifts in signal activation patterns occurred when physical loading or wearable interface conditions changed.

Learning steps: models of intent-driven lower limb prosthesis use · Imperial · PhD

Tried and failed

threshold-based proximity sensing for contact detection applied to wearable sensor coupling validation. Outcome: did not generalise. Reason: High false negative rate yielding only 29.7% sensitivity in detecting sensor detachment events.

Optimal Head Impact Signal Processing and the Description and Perception of Head Impact Exposure in Female Adolescent Ice Hockey Players · Virginia Tech · Doctorate

Tried and failed

tensile strain mode physiological transducer placement applied to respiratory monitoring wearable sensor. Outcome: worse than baseline. Reason: stretching mode caused pressure cancellation, resulting in substantially lower sensitivity than compression mode

Stretchable wearable wireless sensors for physiological monitoring of humans and dogs · Imperial · PhD

Lost to a baseline

Wrist-worn sensors underperformed chest-worn sensors across all 5 holding assessment scenarios (0.738 vs 0.870 accuracy in Scenario 1)

Leveraging pervasive data to study and support mother-infant dyads in the wild · UT Austin · PhD

Considered and rejected

Considered and rejected: Rejected attaching strain sensors directly to the skin with tape due to difficulty in consistently replicating sensor placement across sessions without a trained professional.

Stretch sensors for measuring knee kinematics in sports · Imperial · PhD

Fixed thresholds and proprietary vendor algorithms fail to generalize or accurately detect events

5 theses · 5 institutions

Proprietary vendor event classification algorithms misclassified genuine impacts as spurious artifacts and showed low accuracy compared to validated activity diaries. Fixed state machine thresholds triggered frequent false positive activations across varying postures, and fixed percentage outlier thresholds generalized poorly across individual sensors.

Tried and failed

threshold-based electromyography state machine controller applied to wearable movement assistance. Outcome: did not generalise. Reason: fixed thresholding caused frequent false positive activations across varying task postures and movement heights

Assisting and Evaluating Upper Extremity Movements with Wearables Systems · Harvard · PhD

Tried and failed

proprietary vendor event classification algorithm applied to wearable kinematic sensor impact detection. Outcome: did not generalise. Reason: algorithm misclassified genuine impacts as spurious artifacts and missed true events compared to video verification

SEX DIFFERENCES IN HEAD IMPACT BIOMECHANICS AND QUANTITATIVE FUNCTIONAL DEFICITS DUE TO REPETITIVE LOADING IN HIGH SCHOOL SPORTS · Penn · PhD

Considered and rejected

Considered and rejected: Rejected using wearable sensor spectral monitoring data and activity diaries for quantitative prior-light-history tracking due to sensor inaccuracies/malfunctioning and inconsistent participant reporting.

Alertness in work environments : on the role of indoor daylight exposure · EPFL · PhD

Considered and rejected

Considered and rejected: Using a fixed percentage threshold for Mahalanobis distance outlier removal was rejected because it generalizes poorly across individual sensors compared to probability-based thresholds.

Security and Reliability in Pervasive Computing · Politecnico di Torino · PhD

Tried and failed

wearable sensor heuristic activity classification applied to travel mode and physical activity detection. Outcome: worse than baseline. Reason: built-in proprietary algorithms showed low accuracy compared to validated self-reported travel diaries

Applications of causal inference in environmental policy and transport studies · Imperial · Doctorate

Discrepancies across hardware devices and populations impair cross-subject model transferability

5 theses · 5 institutions

Integrating heterogeneous consumer devices suffered from inter-device measurement variability, and research-grade wearables exhibited higher resting heart rate measurement error than consumer units. Adding extra inertial measurement units degraded cross-subject generalization for speed estimation, while multi-country generalized models were outperformed by localized region-specific models.

Tried and failed

integrating heterogeneous consumer wearable sensor streams applied to remote physical activity tracking. Reason: inter-device measurement variability undermined data comparability across study participants

Rehabilitation through exercise prescription for cardiac patients using an artificial intelligence-based programme · Imperial · PhD

Tried and failed

training subpopulation-specific machine learning models applied to movement classification from wearable sensors. Outcome: worse than baseline. Reason: smaller subpopulation training dataset size hurt generalization compared to pooling all subject data

Fall detection and balance control during human movement · UT Austin · PhD

Lost to a baseline

Research-grade wearables (Empatica E4, Biovotion Everion) had higher resting HR measurement error (MAE 13.9 ± 7.8 bpm) than consumer devices (MAE 7.2 ± 5.4 bpm).

Discovering Digital Biomarkers of Glycemic Health from Wearable Sensors · Duke · Doctorate

Lost to a baseline

Multi-country generalized machine learning models were outperformed by continent-specific and country-specific models for smartphone-sensing-based mood and activity inference.

The iLog methodology for fostering valid and reliable Big Thick Data · University of Trento · PhD

Tried and failed

multi-sensor fusion with additional inertial measurement units applied to locomotion speed estimation. Outcome: worse than baseline. Reason: additional sensors did not reduce error and degraded user-independent cross-subject generalization

Sensor Fusion Representation of Locomotion Biomechanics with Applications in the Control of Lower Limb Prostheses · Georgia Tech · PhD

Fixed biomimetic torque profiles fail to adapt to individual dynamics in wearable robotic assistance

2 theses · 1 institutions

Applying biologically inspired fixed torque profiles failed to produce statistically significant metabolic reductions compared to unassisted walking. Mismatched actuation timing and force profiles disrupted natural user biomechanics and increased metabolic effort relative to individualized human-in-the-loop optimization.

Tried and failed

biomimetic torque profiles for wearable assistance applied to locomotion metabolic cost reduction. Outcome: no signal. Reason: fixed biological torque profiles failed to yield statistically significant metabolic reductions compared to unassisted walking

Soft Exosuits for Improved Walking Efficiency and Community Based Post-Stroke Gait Rehabilitation · Harvard · PhD

Tried and failed

applying mismatched actuation profiles across movement modes applied to assistive wearable robotics control. Outcome: worse than baseline. Reason: incorrect timing and force profile disrupted natural biomechanics and increased metabolic effort

Soft Hip Exosuit Optimization for Improving Mobility in Healthy Young Adults and Individuals with Parkinson’s Disease · Harvard · PhD

Tried and failed

biomimetic control timing parameterization applied to wearable robotic gait assistance. Outcome: worse than baseline. Reason: biologically-inspired profiles failed to account for individual user dynamics compared to individualized human-in-the-loop optimization

Soft Hip Exosuit Optimization for Improving Mobility in Healthy Young Adults and Individuals with Parkinson’s Disease · Harvard · PhD

Left open by the authors

Problems the authors named and did not get to.

Left open

Test the smart wearable system on a larger, diverse population beyond healthy young adults for dynamic cardiac and respiration monitoring. Blocker: Requires custom physical wearable hardware and recruitment of human clinical cohorts for dynamic physiological data collection

A Novel Smart Wearable System with Edge Computing AI for Cardiac Disease Detection and Continuous Monitoring · Texas Tech · PhD

Left open

Develop calibration-free generalized torque models or bodyweight-based calibration procedures for multimodal wearable sensors without isokinetic dynamometers. Blocker: Requires custom multimodal hardware (IMUs and soft sensors), human subject testing, and ground-truth biomechanical measurement equipment

Tracking Joint Kinematics and Muscle Kinetics with Multimodal Wearable Sensors · Harvard · PhD

Left open

Develop wearable multimodal sensing methods to detect postprandial hypotension and nocturnal non-dipping blood pressure. Blocker: Requires specialized wearable multimodal cardiopulmonary sensor hardware and clinical study data on CVAD patients.

Advancing Wearable Cardiopulmonary Monitoring Through Multimodal Sensing of Cardiovascular, Pulmonary, and Respiratory Muscle Function · Georgia Tech · PhD

Left open

Develop adaptive signal selection algorithms for redundant sensor arrays to dynamically correct for wearable placement misalignment without ground truth data. Blocker: Requires custom physical wearable sensor hardware (SCARS soft strain gauges, ultrasound arrays) and real-time physical acquisition apparatus

Multi-Modal Deformation Sensing for Evaluating Muscle Function · Harvard · PhD

Left open

Integrate digital accelerometers and input force sensors into wearable active vibration hardware while reducing the accelerometer count to a single output. Blocker: Requires designing, fabricating, and testing custom physical wearable sensor hardware

Novel Methods Using Acoustics and Bioimpedance to Assess Musculoskeletal Health and Performance · Georgia Tech · PhD

Left open

Evaluate joint feature estimation, spatio-temporal sEMG heatmaps, and alternative neural network architectures for multi-step muscle fatigue forecasting horizons. Blocker: Requires sEMG data from the custom wearable device developed in the thesis

Lower back muscle activity and fatigue during activities of daily living using a novel wearable device and machine learning · Imperial · PhD

Left open

Implement the dynamic EMG decomposition and control pipeline on embedded wearable hardware and evaluate hardware trade-offs. Blocker: Requires custom embedded hardware design and wearable physical apparatus/sensors for physical testing.

Non-invasive neural interfacing for wearable electromyographic systems · Imperial · PhD

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