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Nowadays day-to-day digital communication and social life has only fortified with the ongoing pandemic. People enjoy communication and information across various (direct) messaging platforms and accepted its ever-increasing impact on public discourse and society. While traditional platforms implement user profiles enabling social credit, the landscape also includes anonymity. Yet, a new type of application combining anonymity with a strong spatial focus, hyperlocality, emerged over recent years. To this point, platform implications of both uniquely combined design properties largely remain unknown.
In this thesis, we provide a first data-driven holistic view on Jodel that combines both properties. We leverage unbiased complete ground truth information to dissect a plethora of communities across two different countries: Germany and the Kingdom of Saudi Arabia. This work follows a platform perspective identifying four major essentially important areas revolving around the individual.
That is, we begin with a broad analysis of three User Adoption processes along three different applications. After discussing our measurements of the user base adoption of the German COVID-19 digital contact tracing application, we provide evidence of well-established platforms being re-purposed as a side channel to evade censorship in the ongoing Russo-Ukrainian hybrid war. We further showcase that the very same platform ingredients may yield vastly different outcomes on the messaging app Jodel. While any online platform builds upon User Interactions, we structurally characterize Jodel behavior across both countries. We discuss structural disparities and detail platform implications - solely induced by local user behavior. An in-depth look into the Saudi community landscape closes a research gap to platform usage in a different society, identifying differences.
Further, we discuss User Content analyzing information diffusion. Taking content to the next level, we developed a multidimensional classification scheme for intents (why) and topics (what) of social media messages and provide details of a crowdsourced campaign for Saudi Arabian contents. With neural word embeddings as a tool for making text tangible and the prevalence of emoji in social media communication, we discuss quantitative and qualitative insights to word-emoji embeddings reflecting semantics. Additionally, we make such embeddings interpretable and provide evidence that our method is well in line with human judgement.
In terms of User Management, we detail insights to distributed moderation processes and model the threat of abusive content. In the long term, platforms need to establish a sustainable, preferably growing, environment. That is, we next discuss user lifetime and possibly early churn factors, while modeling user lifetime from metadata. We finish with a blueprint of data-driven long-term quality of experience analyzes in a controlled massively multiplayer online game (MMOG) environment.
In this dissertation, I present five articles regarding two relevant discussions within the field of energy economics: First, three papers discuss the German energy transition and in particular the increasing shares of renewable energies, its cost, benefits and respective challenges to its realization. Second, two papers discuss potential asymmetric pricing in the retail fuel sector in Germany, realizing an analysis with significantly improved data sets compared to earlier studies to answer more specific research questions.
The first three articles focus on the reconstruction of the German energy market into a low-carbon emission setting, especially by utilizing renewable energies. First, the analysis concentrates on the developing energy policy-related goals and the energy economic status-quo, such as the functioning of the system of feed-in tariffs within the market for renewable energies and its general effects on costs. Second, the study deals more deeply and with a quantitative emphasis on the roll-out of renewable energies in Germany and especially its economic effects, such as costs and benefits for energy consumers. Results showed that until 2030, German electricity consumers will pay around €2011 200 billion for RES installations built before the end of 2011. Third, related to the public opinion on the energy transition process, the dissertation unfolded challenges and misconceptions and offers implications for an improved communication approach. The analysis showed by the use of qualitative, semi-structured, in-depth expert interviews that despite the alleged clarity of goals, about two dozen questioned German energy stakeholders have very diverse reasons for the energy transition. The results indicated that one crucial reason is climate protection while a second one is energy autarchy. However, the heterogeneity of goals and conflicting objectives can lead to social tensions and mistrust, which can be appropriately addressed with specific communication methods (e.g. infographics).
The last two articles focus on econometric analyses regarding potential asymmetric pricing within the German retail fuel sector. In particular, the two papers examine the potential existence of Rockets and Feathers, i.e. higher adjustment speeds of retail fuel prices after oil price increases compared to oil price decreases. The dissertation analyzed a tremendous amount of data regarding retail diesel prices from two databases, compiled and processed by the author. The analysis proved with the help of Error Correction Models (following Engle/Granger) that e.g. specific major brands of retail fuel station as well as the local competitive environment influence the probability of Rockets and Feathers. Additionally, the analysis revealed that the nature of Rockets and Feathers is not static over time, i.e. the magnitude of the effect has dynamics across different time periods and consumer behavior can be seen as one reason for the phenomenon of asymmetric pricing.
Im Zuge der voranschreitenden drahtlosen Vernetzung von Systemen wie auch von Systemkomponenten im Bereich der Consumer-Elektronik als auch der Industrie wird die Leistungsversorgung von beweglichen Komponenten immer wichtiger. Die meisten dieser Komponenten sind batteriebetrieben und mit ihrer steigenden Anzahl erhöht sich auch die Nachfrage nach Konzepten für ihre kontaktlose Versorgung mit Energie. Dabei hat sich vor allem die induktive Leistungsübertragung (engl. inductive power transfer (IPT)) als leistungsstarke und weitverbreitete Technologie etabliert. Durch die magnetische Kopplung zweier in geringem Abstand angeordneter Spulen wird kontaktlos, aber höchst effizient Leistung übertragen.
Zusätzlich zur Leistung sollen aber auch Informationen bzw. Steuerungsbefehle zwischen der stationären Ladestation und den mobilen Verbrauchern ausgetauscht werden. Lässt sich über die magnetisch gekoppelten Spulen bereits eine Wechselstromleistung in Form von HF-Signalen übertragen, muss dies auch für modulierte HF-Signale zur Informationsübertragung möglich sein. Diese Arbeit stellt ein Konzept vor, das ein Leistungsübertragungssystem mit induktiv gekoppeltem Spulenpaar um ein Kommunikationsmodul zur bidirektionalen, robusten Übertragung von digitalen Informationen erweitert.
Zunächst werden in dieser Arbeit die Rahmenbedingungen der IPT und die Anforderungen an die Nachrichtenübertragung für ein kombiniertes Daten- und Leistungsübertragungssystem vorgestellt. Hierzu wird unter Nutzung ein und derselben Koppelspulen ein durch Frequenzmultiplexverfahren vom Leistungskanal getrennter Übertragungskanal realisiert. Über diesen Kanal lässt sich die induktive Datenübertragung realisieren. Ein weiterer Teil der Untersuchungen stellt dar, wie einzelne Nachrichtenpakete optimal an die Kanalverhältnisse angepasst und damit unter verbesserten Bedingungen übertragen werden können. Dabei kommen moderne Modulationsverfahren zum Einsatz, deren Grundlagen ebenfalls in dieser Arbeit erläutert werden. Ab- schließend wird die Technologie mit Hilfe eines Prototypen demonstriert und daran messtechnisch die Performanz des Systems belegt. Abgerundet wird die Arbeit mit einer Diskussion der Messergebnisse und einem Vergleich mit dem aktuellen Stand der Technik. Hierdurch kann die Frage beantwortet werden, ob die Technologie unter industriellen Betriebsbedingungen einsetzbar ist.
This paper offers a new perspective on heritage interpretation as a mechanism for understanding heritage sites. It builds a theory of understanding for heritage interpretation based on constructivism perspectives, which shift the focus of attention from heritage interpretation and the process of understanding as a purely cognitive process into a communicative one. In such a view understanding a heritage site means meeting orientation expectations put forth by heritage interpreters in interpretive provision. By analyzing visitor responses (emotional, verbal and behavioural) managers of a heritage site and heritage interpreters are able to determine whether orientation expectations have been met and thus whether understanding took place. In so far understanding of a heritage site means orienting visitors’ perceptions of and behaviours at a heritage site. The paper also analyses the role of culture in the process of understanding and in the process of heritage interpretation. Culture as such does not influence understanding, nevertheless the collective knowledge systems inherent in it are important for the process of understanding and communication, as they offer the meanings, structures and symbol systems that allow the individuals of a particular cultural group to communicate effectively with each other. Because cultures are characteristic of having a pattern and overlapping with each other, a communication and understanding between the individuals of various cultures is a difficult but not impossible process. In order to ensure effective communication and reaching understanding a communication model for heritage interpretation was suggested with three interlinked components (team of communicators, active meaning-maker and interpretive medium), which ensure message formation, interpretation and exchange. In order to assist in communication with various visitors, and especially visitors from different cultural backgrounds, some techniques in the construction of information have been analysed, which allow assisting in reaching understanding on the presented issues in heritage interpretation. These techniques are framing, making of themes and stories. The use of these techniques in the construction of the interpretive information, as well as the overall influence of interpretive provision for understanding, have been tested in two cross-sectional studies. These studies have shown that, in view of constructivism theories, a well developed interpretive activity is able to contribute to a better understanding of a heritage site.