Closing the loop between neural network simulators and the OpenAI Gym

Since the enormous breakthroughs in machine learning over the last decade, functional neural network models are of growing interest for many researchers in the field of computational neuroscience. One major branch of research is concerned with biologically plausible implementations of reinforcement learning, with a variety of different models developed over the recent years. However, most studies in this area are conducted with custom simulation scripts and manually implemented tasks. This makes it hard for other researchers to reproduce and build upon previous work and nearly impossible to compare the performance of different learning architectures. In this work, we present a novel approach to solve this problem, connecting benchmark tools from the field of machine learning and state-of-the-art neural network simulators from computational neuroscience. This toolchain enables researchers in both fields to make use of well-tested high-performance simulation software supporting biologically plausible neuron, synapse and network models and allows them to evaluate and compare their approach on the basis of standardized environments of varying complexity. We demonstrate the functionality of the toolchain by implementing a neuronal actor-critic architecture for reinforcement learning in the NEST simulator and successfully training it on two different environments from the OpenAI Gym

A Meta-Study and Content Analysis of Science Fiction in Computer Science Research

Ph.D

A novel compound targeting microglia activation

Microglia, the resident macrophages of the brain, monitor the central nervous system (CNS) homeostasis. Alterations in homeostasis activate microglia in a variety of ways. Upon a patho-logical stimulus microglia change their appearance from a ramified into an amoeboid morphol-ogy, increase their phagocytic activity, and release pro-inflammatory cytokines and nitric oxide (NO). This response is involved in the pathological process in acute and chronical neuroinflam-matory disease such as stroke, multiple sclerosis, or schizophrenia. A dysregulated microglial activation can improve or exacerbate the outcome of those diseases. Therefore, it is of therapeu-tic interest to identify new compounds, which modulate the activation process of microglia spe-cifically. In this thesis, I identified a novel compound which inhibits specifically the induced NO release in microglia and macrophages independent of the applied pathological stimulus. We screened a library of 16544 compounds for their ability to interfere with lipopolysaccharide (LPS) induced NO release in the microglial cell line BV-2 and verified the results in the primary cultured neo-natal microglia. The compound showed a dose dependent reduction of NO after stimulation with LSP, interferon gamma (IFNγ), and polyinosinic:polycytidylic acid (polyIC) without being cyto-toxic. The LPS-induced release of proinflammatory cytokines TNFα, IL1β, and IL6 was not al-tered in the presents of the compound. I could show that the basal and LPS activated phagocy-tosis in microglia remained untouched, while it showed some influence on microglial migration. Furthermore, I could show that the compound does not interfere with the transcriptional regu-lation of the inducible nitric oxide synthase (iNOS), the enzyme responsible for the induced NO release in microglia and macrophages, and that it does decrease the NO release in already acti-vated microglia. The compound has a unique protein-like structure, composed of 4 proteinogenic and artificial amino acids. This chemical structure is new to the field of nitric oxide synthase (NOS). Its cell based IC50 value of 104 nM is below those of commonly used NOS inhibitors. In a prove of concept experiment, I could show that the application of this compound improves the outcome of stroke in mice

The Swiss National Bank's monetary policy concept - an example of a 'principles-based' policy framework

The practice of monetary policy has evolved a great deal since the early 1990s. This evolution was significantly influenced by rapid developments in the theory of monetary policy. A new consensus about 'principles-based' monetary policy appears to be emerging. It marries a firm long-term anchor for nominal stability, rooted in the original ideas behind inflation targeting, with short-term flexibility, based on a more discretionary and pragmatic approach to monetary policy. The SNB's monetary policy framework - with a firm nominal anchor but with an emphasis on the need for flexibility - reflects, to a considerable degree, the emerging academic consensus about best-practice monetary policy. With its successful seven-year track record, it may serve as an interesting case study for a policy aiming at an intermediate position between full discretion and rigidly defined short-term inflation targeting.Swiss National Bank, monetary policy, inflation targeting, rules, discretion

Media Accessibility Policy in Theory and Reality: Empirical Outreach to Audio Description Users in the United States

Audio description, a form of trans-modal media translation, allows people who are blind or visually impaired access to visually-oriented, socio-cultural, or historical public discourse alike. Although audio description has gained more prominence in media policy and research lately, it rarely has been studied empirically. Yet this paper presents quantitative and qualitative survey data on its challenges and opportunities, through the analysis of responses from 483 participants in a national sample, with 334 of these respondents being blind. Our results give insight into audio description use in broadcast TV, streaming services, for physical media, such as DVDs, and in movie theaters. We further discover a multiplicity of barriers and hindrances which prevent a better adoption and larger proliferation of audio description. In our discussion, we present a possible answer to these problems - the UniDescription Project - a media ecosystem for the creation, curation, and dissemination of audio description for multiple media platforms