Deep speech inpainting of time-frequency masks

Transient loud intrusions, often occurring in noisy environments, can completely overpower speech signal and lead to an inevitable loss of information. While existing algorithms for noise suppression can yield impressive results, their efficacy remains limited for very low signal-to-noise ratios or when parts of the signal are missing. To address these limitations, here we propose an end-to-end framework for speech inpainting, the context-based retrieval of missing or severely distorted parts of time-frequency representation of speech. The framework is based on a convolutional U-Net trained via deep feature losses, obtained using speechVGG, a deep speech feature extractor pre-trained on an auxiliary word classification task. Our evaluation results demonstrate that the proposed framework can recover large portions of missing or distorted time-frequency representation of speech, up to 400 ms and 3.2 kHz in bandwidth. In particular, our approach provided a substantial increase in STOI & PESQ objective metrics of the initially corrupted speech samples. Notably, using deep feature losses to train the framework led to the best results, as compared to conventional approaches.Comment: Accepted to InterSpeech202

Understanding coral reefs in an impacted world: Physiological responses of coral reef organisms to coastal pollution and global warming

Coral reefs are facing a multitude of anthropogenic disturbances at ever higher frequencies and magnitudes. As a consequence, these ecologically and economically important ecosystems are degrading worldwide. Reef managers lack knowledge on how fish, corals and coral larvae respond to the effects of local and global stressors. This thesis reveals the significance of chemical pollution from localized sources. Two common pollutants (diesel and a surfactant) caused metabolic changes in a fish and coral species. Interactive effects were found and additional stress with high temperature mostly resulted in additive effects. In in-situ observations water quality influenced bacterial biofilm communities and the recruitment of coral larvae which is essential for coral reef recovery. Future coral reef management needs to address these issues more specifically to give coral reefs the chance for adaptation to global stressors and increase coral reefs recovery via recruitment through coral larvae

Gradients of anthropogenic stress in Indonesian coral reefs Implications for bacterial community composition and aggregate formation

The Indonesian Spermonde Archipelago, like other coral reefs located in close vicinity to urban areas, is confronted with a multitude of local anthropogenic stressors. A combination of experimental and observational studies was conducted at several fringing reefs and in the water column of the Archipelago during two sampling campaigns. Water quality parameters were not gradually decreasing with increasing distance from Makassar. Instead, there were two contrasting regions, one eutrophic inshore zone and the remaining, oligotrophic shelf. Bacterial community compositions were very distinct between those two described zones. Additionally, significantly higher total aggregated volume and sedimentation rates were observed in the eutrophic zone compared sampling within the oligotrophic outer shelf zone. Data presented in this thesis conclusively showed that dense human populations on the mainland and on the individual islands exerted a clear and measurable influence on the investigated water quality parameters, but that influence was restricted to a narrow zone close to the coast