Lieber Po-Hung Li

A micro-scale fiber-optic sensor based on the Fabry-Pérot interferometric principle is proposed and experimentally demonstrated. The device comprises a single-mode optical fiber, a hollow-core capillary, and an ultrathin metallic diaphragm, forming a compact sensor structure with advantages of low fabrication cost, simple manufacturing, and ultra-small dimensions. The dual-parameter sensing strategy exploits time-scale separation and complementary demodulation domains, using intensity-based demodulation at a fixed quadrature point to capture fast acoustic-induced phase perturbations, while temperature sensing is achieved by tracking the slow spectral drift of the interference fringes caused by thermal expansion and thermo-optic effects. Comprehensive multiphysics experiments were conducted to evaluate both acoustic and thermal sensing capabilities, with emphasis on the effect of diaphragm thickness on overall performance. Acoustic characterization revealed a wide frequency response from 10 Hz to 20 kHz, a maximum signal-to-noise ratio of 46.1 dB, a minimum total harmonic distortion of 0.051%, and a minimum detectable pressure of 12.9 μPa/√Hz at 1 kHz. Thermal measurements confirmed reliable operation over 50 °C - 300 °C, achieving a sensitivity of 13.3 pm/°C with excellent linearity (R² > 0.99). These results demonstrate that the proposed Fabry-Pérot fiber-optic sensor provides high-performance and cost-effective solutions for applications in acoustic detection, temperature monitoring, and wearable sensing technologies.

Audio super-resolution (ASR) restores missing high-frequency content from low-bandwidth speech, which frequently arises in the Internet of Things (IoT) acoustic sensing and edge voice interfaces due to power, bandwidth, and latency constraints. Recent Mamba-based models improve long-range modeling efficiency but are often adapted from vision templates and are not optimized for ASR deployment. We propose UPVM-ASR, an ultralight dual-stream U-Net built on VMamba visual state-space (VSS) blocks to reconstruct magnitude and phase spectrograms in parallel. A channel parallel, weight-shared parallel visual state-space (PVSS) reduces parameter redundancy while retaining global–local spectrotemporal modeling with linear complexity. UPVM-ASR is highly compact, achieving 0.41M parameters and 1.00 GFLOP, and remains competitive across 16-and 48-kHz targets on the VCTK dataset. UPVM-ASR attains the lowest log-spectral distance (LSD) in the most challenging settings (from 2 to 16 and 8 to 48 kHz) while maintaining strong ViSQOL and STOI scores. These results indicate that optimized lightweight state-space U-Nets can deliver high-fidelity ASR under tight compute and communication budgets. Furthermore, to assess deployment and robustness, we additionally provide a deployment-oriented pure C implementation and benchmark runtime on embedded platforms, as well as report results under noisy/out-of-domain conditions on VCTK-DEMAND and NISQA datasets.

In challenging conditions such as low signal-to-noise ratios and distant speech, microphone-based automatic speech recognition (ASR) struggles with clarity. To remedy this, laser Doppler vibrometer (LDV) technology is integrated into the ASR system and a data augmentation approach is employed to generate training data containing LDV attributes. The performance of the ASR, assessed using word error rates, showed superior results with the data augmentation approach compared to the baseline ASR system trained solely on real LDV data. Thus, with the aid of data augmentation, LDV can potentially be a sound-capturing device for ASR, offering valuable insights for future applications.

Background: Steady-state auditory evoked responses (SSAERs) are promising indicators of major auditory function. The improvement in accessibility in the clinical setting depends on the standardization and definition of the characteristics of SSAERs. There have been some insights into the changes in the interhemispheric dominance of SSAERs in some clinical entities. However, the hemispheric asymmetry of SSAERs in healthy controls remains inconclusive. Methods: Twelve right-handed healthy volunteers with normal hearing were recruited. Steady-state auditory evoked fields (SSAEFs) were measured binaurally using magnetoencephalography (MEG) under pure-tone auditory stimuli at 1000 Hz with an amplitude modulation frequency of 43 Hz. The laterality index, based on the ratio of SSAEF strength over the right hemisphere to that over the left hemisphere, was also analyzed. Results: The SSAEFs source was localized bilaterally on the superior temporal plane, with an orientation centripetal to the auditory cortex. The laterality index ranged from 1.1 to 2.3, and there were no sex differences. In all subjects, the strength of the SSAEFs was significantly weaker in the left hemisphere than in the right hemisphere (p = 0.014). Conclusion: Right-sided dominance of the SSAEFs was verified in subjects with normal hearing. Acoustic sources clinically available in audiometric tests were used as stimuli. Such a simplification of parameters would be helpful for the standardization of precise production and the definition of the characteristics of SSAERs. Because MEG is still not easily accessible clinically, further studies using electroencephalography with larger sample sizes are necessary to address these issues.

Cochlear implantation is a major treatment option for severe-to-profound hearing loss. By insertion into the cochlea and stimulation of the cochlear nerve, cochlear implantation can improve the performance of hearing and speech performance of the implantees. The microenvironment of the cochlea is innate and gets disturbed in response to the insertion of a foreign body. However, real-time changes inside the cochlea in terms of electrophysiology at the molecular level can never be investigated in vivo in human beings. Thus, impedance is a good guide that reflects the electrophysiology inside the cochlea. Because the initial measurement of impedance cannot be performed earlier than the traditional interval of 1 month postoperatively, early changes in impedance have not been explored until recently; however, surgeons are now trying the initial switch-on earlier than 1 month after implantation. This review discusses the scenario of electrophysiological variation after early switch-on in <1 day postimplantation. Evidence has shown that fluctuations in impedance after implantation depend on the interplay between cell cover formation, fibrosis, electrode design, and electrical stimulation. Further studies addressing the correlation between impedance and clinical parameters are required to develop reliable biomarkers for better performance of cochlear implantation.

Purpose: This study aimed to investigate (1) the role of mouth puffing phenomenon and upper airway features in obstructive sleep apnea (OSA) and (2) whether mouth-taping during sleep alleviated the severity of OSA. Participants and Methods: Seventy-one participants underwent a two-night home sleep test (the first day sleeping normally; the second day sleeping with their mouths being taped); their oximetry desaturation index (ODI) and mouth puffing signals (non-mouth puffing, complete mouth puffing, intermittent mouth puffing (IMP), and side mouth puffing) were detected by a validated fingertip pulse oximeter and a mouth puffing detector. The participants were grouped into the ODI-improved group and the ODI-not-improved group according to their sleeping test results. The radiograph was taken by cone-beam computed tomography and cephalometries. Upper airway features including airways, soft tissues, and oral cavity variables were measured. Results: Participants with severe OSA showed a higher IMP percentage compared with those with normal, mild, and moderate OSA (severe: 33.78%, moderate: 22.38%, mild: 14.55%, normal: 0.31%, p < 0.001). In all participants, the ODI and the percentage of SpO₂ under 90 (T90) were positively related to body mass index (BMI) (r = 0.310 and 0.333, respectively), while ODI and T90 were negatively correlated with the minimum width of the airway (r = − 0.473 and − 0.474, respectively); all mentioned relationships were significant (p < 0.05). Conclusion: IMP proportions were found to be higher in the half of participants whose ODI did not improve after mouth-taping and in those with severe OSA. Moreover, OSA patients with higher ODI, higher T90, and higher proportions of IMP were more likely to have a narrower upper airway.