Cátia Pinho

Weak voicing in fricative production

Understanding of the production mechanisms of voiced fricatives lags significantly behind that of other phonemic categories of speech. This paper presents a new voicing classification criterion to distinguish the voicing in fricatives from that of their contextual vowels in VCV tokens: weak vs strong voicing. The criterion is based on the oral airflow, distinguishing it from previous criteria based jointly on the acoustic and EGG signals. Aerodynamic and EGG recordings of four normal adult speakers (two females and two males), producing a speech corpus of 9 isolated words with the European Portuguese (EP) voiced fricatives /v, z, ?/ in word-initial, -medial and -final position, and the same 9 words embedded in 42 different real EP carrier sentences, were analysed. Fricatives were characterised in terms of oral airflow, fundamental frequency, first formant intensity level and glottal open quotient in absolute terms and relative to the values found in their surrounding vowels. The voicing during fricative production presented properties distinct from the voicing of the contextual vowels, leading to the development of a classification criterion based on the relative amplitude of the oscillations in the oral airflow signal. This contributes to distinguish voicing in fricatives from the modal voicing of the vowels

Aerodynamic measures of speech in unilateral vocal fold paralysis (UVFP) patients

Abstract This paper reports the recording and analysis of an aerodynamic database of 51 words produced by four patients with unilateral vocal fold paralysis. The vowel–fricative–vowel boundaries were manually annotated, and the mean absolute oral airflow amplitude (OA), fundamental frequency (f0), and first formant intensity (IF1) were extracted from a 20 ms window in the steady state of each phone. A case study approach to analysis of phonatory behaviour for the subjects is presented. Significant differences were found between the absolute OA and IF1 for different phones. Large between-subject variations in absolute measures for OA and f0 were found. Relative values calculated from the difference in these parameters between phones show consistency for subjects of the same gender.

Effects of a respiratory physiotherapy session in patients with LRTI: a pre/post‐test study

The role of respiratory physiotherapy (RP) in lower respiratory tract infections (LRTI) has been questioned. However, studies have focused on hospitalised patients, and the presence/absence of an underlying disease has been neglected.

Integrated Approach for Automatic Crackle Detection Based on Fractal Dimension and Box Filtering

Crackles are adventitious respiratory sounds RS that provide valuable information on different respiratory conditions. Nevertheless, crackles automatic detection in RS is challenging, mainly when collected in clinical settings. This study aimed to develop an algorithm for automatic crackle detection/characterisation and to evaluate its performance and accuracy against a multi-annotator gold standard. The algorithm is based on 4 main procedures: i recognition of a potential crackle; ii verification of its validity; iii characterisation of crackles parameters; and iv optimisation of the algorithm parameters. Twenty-four RS files acquired in clinical settings were selected from 10 patients with pneumonia and cystic fibrosis. The algorithm performance was assessed by comparing its results with a multi-annotator gold standard agreement. High level of overall performance F-score=92% was achieved. The results highlight the potential of the algorithm for automatic crackle detection and characterisation of RS acquired in clinical settings.

InP MMI based polarization splitter for Photonic Integrated Circuits

In this paper is presented a new multi-mode interference MMI polarization splitter for Photonic Integrated Circuits PICs. It was designed using the Fraunhofer Heinrich-Hertz-Institut (HHI) commercial multilayer waveguide in Fe doped InP E1700. The central operation wavelength for what this device was designed is 1534 nm. This device can be very useful in the new communication networks for example it can be used as an upgrade in next generation passive optical networks that want to explore polarization diversity. The simulations reported in this paper point out to insertion losses of only 1.95 dB for Transverse Electric (TE) polarization and 1.23 dB for Transverse Magnetic (TM) polarization. It also is tolerant to wavelength variations having a 3 dB bandwidth of 28 nm.

Optical transforms and CGH for SDM systems

Spatial division multiplexing (SDM) systems are essential to overcome the increasing demand for higher bandwidth data services. Nevertheless, SDM employment is challenging and complex impairments need to be addressed (e.g., crosstalk and nonlinearities). The use of spatial light modulator (SLM) in core/mode division multiplexing is foreseen to improve channel compensation, by using it as a diffractive device to reconstruct images from computer generated holograms (CGHs). The transparency and passive nature of the application of optical transforms (e.g., Haar transforms (HT) fully in the optical domain) for compression/decompression of data, may allow energy saving and processing capacity relief, by reducing redundant or negligible data. In this study, the concept of combining HT and CGH to improve the processing/storing of high bandwidth demanding data associated with SDM systems is presented. Exploring the implementation of parallel processing of 2D data through integrated optics, for all-optical wavelet transforms and compression, and the use of CGH for spatial light modulation.