This research proposes an fibre bragg grating sensor based real time system which utilizes strain measurements to detect foot positions during plantarflexion and dorsiflexion along with inversion and eversion movements. FBG sensors used to detect distinct strain patterns in which + 689.5 µε tension ensued during plantarflexion while + 1521 µε tension occurred during inversion. Strains reached –2205.4 µε during dorsiflexion and –1478.5 µε during eversion. Strain measurement during gait considered with time has indicated maximum strain at mid-stance and minimum strain at toe-off. A neural network based artificial intelligence model executed automated posture classification which resulted in 86% accuracy and featuring precision of 0.96 and 0.96 F1 score. Ten participants contributed a total of 492 labeled samples across four distinct postures and walking trials. Research results affirm that the FBG sensor system delivers appropriate performance for smart wearable use in rehabilitation process and performance assessment.
Graphene–dielectric multilayers offer a tunable platform for terahertz hyperbolic media and transmission modulation. A theoretical framework implemented in MATLAB is developed to investigate how the graphene Fermi energy influences effective anisotropic permittivity, hyperbolic transitions, lossy modal dispersion, propagation characteristics, and the optical response of periodically stacked graphene–dielectric multilayers of finite thickness. Graphene sheets are described by the intraband Drude conductivity, and the multilayer is approximated as an effective uniaxial medium when its period is much smaller than the terahertz wavelength. The Fermi energy is treated as an idealized uniform tuning parameter across all graphene layers. Changing the Fermi energy strongly modifies the effective transverse permittivity, whereas the axial permittivity remains positive and is primarily determined by the dielectric spacer. For the baseline parameters, the multilayer remains hyperbolic throughout 0.1–10 THz for Fermi energies of 0.2–1.0 eV. The calculated elliptic-to-hyperbolic transition frequencies lie above this band and increase with Fermi energy. The complex longitudinal wave vector is used to quantify modal attenuation, propagation length, and modal figure of merit (FOM), highlighting the importance of accounting for propagation loss when assessing hyperbolic operation. A discrete graphene-sheet transfer-matrix model connects the effective-medium analysis with the optical response of finite multilayers. Transmission, reflection, absorptance, and modulation depth depend strongly on Fermi energy, number of periods, spacer thickness, and incident angle. Together, these analyses provide a unified theoretical framework linking tunable dispersion and modal loss to finite-stack transmission, offering design guidance for graphene-based terahertz hyperbolic media and transmission modulators.
