Utilizing Domain Knowledge in End-to-End Audio Processing

End-to-end neural network based approaches to audio modelling are generally outperformed by models trained on high-level data representations. In this paper we present preliminary work that shows the feasibility of training the first layers of a deep convolutional neural network (CNN) model to learn the commonly-used log-scaled mel-spectrogram transformation. Secondly, we demonstrate that upon initializing the first layers of an end-to-end CNN classifier with the learned transformation, convergence and performance on the ESC-50 environmental sound classification dataset are similar to a CNN-based model trained on the highly pre-processed log-scaled mel-spectrogram features.Comment: Accepted at the ML4Audio workshop at the NIPS 201

Deep Learning for Audio Signal Processing

Given the recent surge in developments of deep learning, this article provides a review of the state-of-the-art deep learning techniques for audio signal processing. Speech, music, and environmental sound processing are considered side-by-side, in order to point out similarities and differences between the domains, highlighting general methods, problems, key references, and potential for cross-fertilization between areas. The dominant feature representations (in particular, log-mel spectra and raw waveform) and deep learning models are reviewed, including convolutional neural networks, variants of the long short-term memory architecture, as well as more audio-specific neural network models. Subsequently, prominent deep learning application areas are covered, i.e. audio recognition (automatic speech recognition, music information retrieval, environmental sound detection, localization and tracking) and synthesis and transformation (source separation, audio enhancement, generative models for speech, sound, and music synthesis). Finally, key issues and future questions regarding deep learning applied to audio signal processing are identified.Comment: 15 pages, 2 pdf figure

Localized patterns in planar gas-discharge systems

A summary is given of parts of the work that has been done on pattern formation in planar ac- and dc- gas-discharge systems with high ohmic and dielectric barrier respectively, at the Institute of Applied Physics of the University of Muenster. In addition, a qualitative reactiondiffusion model is reviewed that takes account of many of the effects that have been observed experimentally

Self-organized quasiparticles and other patterns in planar gas-discharge systems

A summary is given for the work that has been done on pattern formation in planar ac- and dc- gas-discharge systems with high ohmic and dielectric barrier respectively at the Institute of Applied Physics at the University of Muenster. WeIl defined stationary and moving solitary filaments are observed that may be referred to as selforganized quasiparticles. Among others, filaments can be scattered, generated, or annihilated, and the formation of filament clusters ("molecules") is observed. For appropriate parameters filaments in the "gaseous" phase are observed, and the condensation of large assemblies to "crystalline" phase and "liquid" phase is recorded, too. Filaments may generate superstructures e.g. domain patterns. The experimental work demonstrates that a filament is a generic pattern. In addition, reference is made to non-filamentary patterns. Finally, a list of references referring to models and numerical treatment is presented

A political ecology of bauxite extraction at Atewa Forest, Ghana

In 2018, Ghana’s President Akufo-Addo announced “My government is going to implement an alternative financing module to leverage our bauxite reserves, in particular to finance major infrastructure programs across Ghana. This will probably be the largest infrastructure program in Ghana’s history without any addition to Ghana’s debt stock” (Akufo-Addo 2018). In the same year, the government signed a deal with the Chinese state firm Sinohydro in the form of a resource-backed loan with bauxite as collateral. Ghana’s president highlighted the opportunity to develop an integrated bauxite-aluminum industry and stimulate nationwide industrialisation. Due to the lack of transparency and environmental concerns, however, the Sinohydro deal has increased a growing movement against bauxite mining in Ghana, especially in the Atewa Forest Reserve, which is not only a possible mining site, but also a protected biodiversity hotspot. I analyse this dispute from a political ecology perspective. Political ecology examines the political dynamics surrounding material and discursive struggles over the environment. Additionally, political ecologists acknowledge that resources are relational assemblages which are in a constant state of becoming. In this regard, ecology is always political. During three fieldtrips in March 2018, 2019 and 2020, I observed this conflict with the empirical goal to contextualise it. The dynamics, actors and subjects of conflict are related to a variety of factors. Social environmental movements and disputes emerge at certain historical points, specifically in geographical and cultural contexts. Moreover, as I argue, they emerge as a specific set of relationships between structures, institutions, agency and narratives. Therefore, my empirical goal is to contextualise the dispute over the Atewa Forest and analyse how the bauxite reserves at Atewa Forest were and are politicised. For this empirical part, I refer to the framework provided by Dietz and Engels (2020) which examines structure, agency, institutions and narratives. This is done alongside actor-mapping, in order to identify key actors in this conflict. I demonstrate herein that the Ghanaian government is under a lot of pressure, not only from local NGOs, but also from international NGOs, intellectuals (or actors such as Leonardo DiCaprio) and major manufacturing companies that oppose mining in the Atewa Forest. In addition, Ghana has to meet the loan obligations of the Sinohydro deal, and it is yet to build any refineries. Second, as part of my theoretical-conceptual goal, I argue to adapt temporalities to a political ecology of resource extraction. This involves temporalities of resources, temporality surrounding resource extraction and time as a political strategy. Activists have for example urged for a decision to act immediately, but simultaneously they have tried to delay the mining project. By coupling the protection of the forest with global climate discourses, NGOs point out that in times of environmental crisis, it is essential that the forest is protected. They push this agenda forward via open letters, protests and social media campaigns. On the other hand, the delay they hereby produce gives rising attention to this topic. Additionally, by building more pressure, it makes mining at Atewa Forest unattractive to investors who cannot afford any delays. On the contrary, the government promotes imaginaries of future growth, jobs and prosperity. Creating such a historical momentum suggests that now is the right time to solve a long-lasting problem and to decouple seemingly fast economic benefits from long-term environmental pollution. With the theoretical notions of becoming and temporalities in mind, an empirical contextualisation helps attain a detailed understanding on how nature is politicised. The decision to mine bauxite at Atewa Forest is not a given, or logical, per se. For a political ecologist, decisions are inherently political and therefore the result of power asymmetries. Meanwhile, as a result of the always recurring discussions on bauxite mining at Atewa Forest, the building of an extractive industry with its facilities and infrastructure, connected with the promise of fast and rapid industrialisation and prosperity, the forest is – at least currently – still standing