From Simulated Mixtures to Simulated Conversations as Training Data for End-to-End Neural Diarization

End-to-end neural diarization (EEND) is nowadays one of the most prominent research topics in speaker diarization. EEND presents an attractive alternative to standard cascaded diarization systems since a single system is trained at once to deal with the whole diarization problem. Several EEND variants and approaches are being proposed, however, all these models require large amounts of annotated data for training but available annotated data are scarce. Thus, EEND works have used mostly simulated mixtures for training. However, simulated mixtures do not resemble real conversations in many aspects. In this work we present an alternative method for creating synthetic conversations that resemble real ones by using statistics about distributions of pauses and overlaps estimated on genuine conversations. Furthermore, we analyze the effect of the source of the statistics, different augmentations and amounts of data. We demonstrate that our approach performs substantially better than the original one, while reducing the dependence on the fine-tuning stage. Experiments are carried out on 2-speaker telephone conversations of Callhome and DIHARD 3. Together with this publication, we release our implementations of EEND and the method for creating simulated conversations.Comment: Submitted to Interspeech 202

Anticoagulation in the early phase of non-valvular atrial fibrillation-related acute ischemic stroke: where do we stand?

The balance between the risk of early stroke recurrence and hemorrhagic transformation represents the cornerstone of practical management of non-valvular atrial fibrillation (NVAF)-related acute ischemic stroke (AIS). Patients who receive antithrombotic therapy as secondary prevention in the early phase of NVAF-related AIS have a better prognosis compared with patients who do not receive antithrombotic treatment. Recently, the RAF study showed that the best efficacy/safety profile was associated with anticoagulation started between 4 and 14 days from stroke onset. Based on the RAF study, the 2018 American Heart Association/American Stroke Association (AHA/ASA) guidelines suggest starting anticoagulants between 4 and 14 days from stroke onset with a class of recommendation IIa. Strong evidence for the use of direct oral anticoagulants (DOACs) in the early phase of NVAF-related AIS is lacking, because this kind of patients were excluded from phase III randomized clinical trials (RCT) and ad hoc RCTs are ongoing. However, the real life evidence suggests that early starting time of DOACs in patients with NVAF-related AIS is safe and associated with low recurrence risk and all-cause mortality. In the present review the Authors provide an update on anticoagulation in the early phase of NVAF-related AIS with focus on DOACs

Multi-Stream Extension of Variational Bayesian HMM Clustering (MS-VBx) for Combined End-to-End and Vector Clustering-based Diarization

Combining end-to-end neural speaker diarization (EEND) with vector clustering (VC), known as EEND-VC, has gained interest for leveraging the strengths of both methods. EEND-VC estimates activities and speaker embeddings for all speakers within an audio chunk and uses VC to associate these activities with speaker identities across different chunks. EEND-VC generates thus multiple streams of embeddings, one for each speaker in a chunk. We can cluster these embeddings using constrained agglomerative hierarchical clustering (cAHC), ensuring embeddings from the same chunk belong to different clusters. This paper introduces an alternative clustering approach, a multi-stream extension of the successful Bayesian HMM clustering of x-vectors (VBx), called MS-VBx. Experiments on three datasets demonstrate that MS-VBx outperforms cAHC in diarization and speaker counting performance.Comment: Accepted at Interspeech 202

Stray light evaluation for the astrometric gravitation probe mission

The main goal of the Astrometric Gravitation Probe mission is the verification of General Relativity and competing gravitation theories by precise astrometric determination of light deflection, and of orbital parameters of selected Solar System objects. The key element is the coherent combination of a set of 92 circular entrance apertures, each feeding an elementary inverted occulter similar to the one developed for Solar Orbiter/METIS.1 This provides coronagraphic functions over a relevant field of view, in which all stars are observed for astrometric purposes with the full resolution of a 1 m diameter telescope. The telescope primary mirror acts as a beam combiner, feeding the 92 pupils, through the internal optics, toward a single focal plane. The primary mirror is characterized by 92 output apertures, sized according to the entrance pupil and telescope geometry, in order to dump the solar disk light beyond the instrument. The astronomical objects are much fainter than the solar disk, which is angularly close to the inner field of view of the telescope. The stray light as generated by the diffraction of the solar disk at the edges of the 92 apertures defines the limiting magnitude of observable stars. In particular, the stray light due to the diffraction from the pupil apertures is scattered by the telescope optics and follows the same optical path of the astronomical objects; it is a contribution that cannot be eliminated and must therefore be carefully evaluated. This paper describes the preliminary evaluation of this stray light contribution