Subband modeling for spoofing detection in automatic speaker verification

Spectrograms - time-frequency representations of audio signals - have found widespread use in neural network-based spoofing detection. While deep models are trained on the fullband spectrum of the signal, we argue that not all frequency bands are useful for these tasks. In this paper, we systematically investigate the impact of different subbands and their importance on replay spoofing detection on two benchmark datasets: ASVspoof 2017 v2.0 and ASVspoof 2019 PA. We propose a joint subband modelling framework that employs n different sub-networks to learn subband specific features. These are later combined and passed to a classifier and the whole network weights are updated during training. Our findings on the ASVspoof 2017 dataset suggest that the most discriminative information appears to be in the first and the last 1 kHz frequency bands, and the joint model trained on these two subbands shows the best performance outperforming the baselines by a large margin. However, these findings do not generalise on the ASVspoof 2019 PA dataset. This suggests that the datasets available for training these models do not reflect real world replay conditions suggesting a need for careful design of datasets for training replay spoofing countermeasures

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広島経済大学経済学会 2013年度第6回研究集会[2013年12月19日(木)]報告要

Dressing to undress: Learning seduction from Aphrodite’s choral routine. A study of the Kypria (PEG1 F 4, 5)

We are investigating the place of dance and music in the Epic Cycle. Preliminary findings show that vocabulary associated with dancing and music in the few surviving fragments is rare. For example, ὀρχέομαι (Titanomachy, PEG F 6), ὁ ὀρχηθμός and ἡ ἀοιδή (both in Panyasis, PEG F 19, 3) each appear only once. The verb ἀείδω occurs three times. Twice to invoke the Muses (The Little Iliads PEG F 28 and Thebaid PEG F 1). The third use is particularly interesting. It appears in a more substantial fragment of the Kypria (PEG F 5, 5). There, presumably ahead of Paris’ judgment, Aphrodite is dressed and crowned by the Nymphs and Graces, with whom she sings (καλὸν ἀείδουσαι). This extract, reported by Athenaeus, will be at the heart of our contribution. Firstly, we will study the metric of the fragment and the occurrences of some iuncturae (φιλομμειδὴς/χρυσὴ Ἀφροδίτη, καλὸν ἀείδω, πολυπιδάκου Ἴδης) in order to study its composition relative to other passages in the Iliad (3. 393-394; 18. 590-606), the Odyssey (6. 91-109; 18. 192-196) and the Homeric Hymns (3. 194-203; 5. 53-68, 117-121, 257-268; 27. 14-19). Based on this comparison, we will argue that scenes of clothing are associated not only with desire and seduction but also with dancing and the formation of choroi. Subsequently we will compare the fragment with the second song of Demodocos (Od. 8. 266-368): also a hymn according to G. Nagy (2014). Our comparative analysis will confirm the use of an annular structure in the Aphrodite fragment, as previously argued by M. Steinrück (2018). We will establish that in the middle of that structure lies the crown of Aphrodite, another cyclic element