Open Access

With Google’s Flutter framework continuing to grow in popularity for companies and developers alike, the need for an understanding of how to utilize the framework in a large-scale context has become more relevant than ever. The purpose of this thesis is to document the crucial steps most development teams using Flutter in a large-scale application will face. Additionally, a fully documented, large-scale reference application was generated so that other developers may use it as an aid when creating their own Flutter projects on a similar scale. Multiple steps were taken to ensure that optimal solutions were chosen for each aspect of the development process. For each of those aspects, a wide range of possible solutions were explored, compared and analysed. Finally, one of the possible solutions was chosen based on a wide range of scientific papers and community-generated sources. Additionally, an interview with an expert in the field was conducted to further validate those decisions. After the application was fully implemented, ten crucial aspects of the development process were identified. Those ten aspects are now explained in detail in this thesis. Ultimately, the knowledge provided by this thesis can act as a map for peers using Flutter in a large-scale context and help them overcome the crossroads they will most likely come to face.

Digital competences are describing a set of skills, which are necessary to use digital devices and tools with an adequate degree of self-determination. With the ubiquitous digitization of our lives and our society it is important for every citizen to have digital competences. Therefor, it is necessary to educate those competences in schools. As one cannot assume teachers to have enough digital competences to well educate the children of todays classes, this master thesis tries to find out: How to shape the process of teaching digital competences to adolescents in German schools, focusing on including multiple parties from diverse backgrounds into the process? At first, the current situation of teaching digital competences in German schools is analyzed by means of a literature review. After the identification of the challenges within the German system, international best practices are examined. Therefor, four countries, which have reached high scores in the International Computer and Information Literacy Study are selected. Australia, the Czech Republic, Denmark and the Republic of Korea are compared and possible chances for Germany identified. As the next step, expert interviews with divers parties, which have direct or indirect relation to the German education system, are held. The goal of the interviews is to generate ideas on how to support the education system by external help. At the end of the thesis the recommended approach of Motivating External People is presented. Several measures, such as teaching or mentoring students in a guest lecturer model; providing IT support for the hard- and software of the schools or creating Open Educational Resources as education material for the teachers are presented and possible third parties are named. As it is not possible to support the education system from the outside without education system internal persons, it is presented, what needs to change within the system to get the approach working. Therefor, not a complex and system changing approach is presented, but a combined top-down and bottom-up process to motivate external people to support.

Neben den großen Anbietern digitaler Comics mit elektronischem Kopierschutz (DRM) haben sich auch Anbieter für DRM-freie Comics etabliert. Als Open Source-Alternative zu den Plattformen Ersterer wurde im Rahmen des Praxisprojekts die Software ComicLib als Web-App zur Verwaltung digitaler Comicsammlungen geschaffen. Diese ermöglicht die gemeinsame Verwaltung DRM-geschützter sowie -freier Comics. Letz-tere sind außerdem im Webbrowser lesbar. Die im Rahmen dieser Arbeit entstandene And-roid-App soll eine Open Source-Alternative zu den mobilen Apps der Plattformen der gro-ßen Anbieter sein und ComicLib um eine mobile App zur Offline-Nutzung der Comics erwei-tern. Der erste Prototyp wird im Nachgang des Projekts weiter getestet und verbessert, be-vor die erste stabile Version veröffentlicht wird.

For use in a landfill, a laboratory reactor for safe and environmentally friendly biological utilization of low-concentration methane gas will be further developed. The current principle of denitrification-coupled aerobic methane oxidation will be replaced by methane oxidation under anaerobic conditions. Anaerobic methane oxidation offers the advantage that, in addition to methane, nitrate also undergoes biodegradation. Another advantage is that the oxygen content can be significantly lower. This reduces the risk of the formation of an explosive atmosphere in the reactor. Currently, the principle of anaerobic methane oxidation is known. However, organisms capable of doing so are not yet available as a pure culture. Therefore, several biomasses were probed for the ability of anaerobic methane oxidation. It was found that moor-heavy sediment, activated sludge from the leachate treatment plant and biomass from the local biogas plant oxidize methane after the natural carbon source (C source) was been removed.

The electricity network is undergoing a change due to reducing costs for renewable energy sources. Subsidy programs for renewable energy sources are changing and the funding available is being reduced. This will have an impact on anaerobic digestion which in some cases may struggle financially. Overfeeding is one of the most common mechanisms of inhibition in the process, and by shifting to intermittent feeding for on-demand production, this change will provide more information about the digestion process and could be used to detect the beginning of inhibition due to overfeeding. This paper discusses the shift towards intermittent production and how this change can be used to monitor the anaerobic digestion process.