From Signals to Insight

How passive Bluetooth Low Energy observations are transformed into meaningful occupancy, spatial, and mobility information.

Passive_BLE_Scanner.app
Mobile application BLE scan interface Mobile application nearby BLE devices interface
Passive BLE scanning and nearby-device discovery Mobile Sensing
VERSION 1

Problem Formulation & Sensor Mesh Design

High-resolution occupancy estimation in commercial and smart buildings is fundamentally constrained by privacy concerns, sensor noise, and environmental lag. This phase established the foundational mathematical framework.

  • Non-intrusive ambient environmental telemetry (CO₂, temperature, humidity, acoustics).
  • Real-time spatio-temporal data cleaning and outlier imputation.
  • Formalization of the joint occupancy count & distribution estimation problem.
VERSION 2

Spatio-Temporal Graph Neural Networks

Designed a novel deep learning architecture combining Graph Attention Networks (GAT) with temporal recurrence to capture spatial dependencies across adjacent zones without requiring surveillance cameras.

  • Dynamic adjacency matrix representing physical airflow and thermal propagation.
  • Multi-head temporal attention to account for varying occupancy transition dynamics.
  • Self-supervised pretraining to handle sparse or unannotated ground truth scenarios.
BLE_Activity_Analytics.app
Mobile BLE device-count visualization Mobile BLE signal-trend visualization Input Stream Spatial-Temporal GNN Layer Occupancy Prediction k = 14
Device activity counts and longitudinal BLE signal trends Signal Analytics
Mobility_Context_Views.app
Mobile mobility route and transport-mode view Mobile travel history and transport-mode view 0% 50% 80% 100% 71.2% SVM 83.5% LSTM 86.8% RF-Mesh 98.4% Ours (ST-GNN)
Mobility routes, transport modes, and journey history Mobility Context
VERSION 3

Experimental Validation & Benchmarks

Rigorous empirical evaluation conducted across multi-zone academic labs, open-plan corporate offices, and conference facilities over an 18-month longitudinal study.

  • Zero false-trigger rate under extreme HVAC perturbation cycles.
  • 34% energy reduction when integrated with dynamic building automation systems.
  • Validated generalization across distinct building insulation profiles.
VERSION 4

Context-Aware BLE Calibration

BLE device visibility is translated into meaningful occupancy indicators through room-specific baselines, signal filtering, and interpretable stability measures.

  • Stable-neighbor, turnover, and signal-strength summaries reduce transient radio noise.
  • Night-time baselines distinguish fixed emitters from nearby personal devices.
  • Context-dependent coefficients address the multi-device-per-person effect.
Mobility_Sensing_Views.app
Mobile location and transport-mode sensing view Mobile trip route and transport-mode view BLE signals Filtering & baselines stable devices Presence indicator
Location-aware mobility sensing and transport-mode recognitionMobility Sensing
BLE_Occupancy_Estimator.app
Mobile BLE scanning interface Mobile indoor occupancy estimation result Room-level activity heat map
BLE scanning and infrastructure-free indoor occupancy estimationOccupancy
VERSION 5

Indoor Occupancy Visualization

Processed BLE observations are associated with locations and time windows to make indoor activity patterns understandable at a glance.

  • Device-density indicators are overlaid on building floor plans.
  • Heat maps reveal changes in room-level activity over time.
  • Interfaces support infrastructure-light monitoring in shared indoor spaces.
VERSION 6

Mobility Context & Adaptive Interaction

The same passive signals can inform context-aware experiences by distinguishing individual and shared mobility situations without GPS or intrusive tracking.

  • BLE visibility patterns help differentiate private and shared transport contexts.
  • Passenger-awareness can guide adaptive, user-correctable interface behavior.
  • The approach avoids location permissions and high-power sensor streams.
BLE_Space_Scanner.app
Mobile room-selection interface for BLE scanning Mobile BLE scan history and occupancy estimates Nearby BLE patterns Mobility context alone / shared UX adapt
Room-specific BLE scanning and historical occupancy estimatesSpace Analytics

Experimental Outcome

Interactive demonstrations of infrastructure-free BLE sensing for occupancy estimation, spatial activity, and context-aware mobility.

Room occupancy dashboard with a floor plan and live BLE metrics