Development and properties of all-dielectric and metal-dielectric heterostructures at atomic scale

Heterostructures have increasingly attracted attention in recent times to enable various optoelectronic and photonic applications. In this Dissertation, atomic scale heterostructures of two technologically relevant oxides, such as, Al2O3 and TiO2 were developed by plasma enhanced atomic layer deposition (PEALD) technology. Their growth, composition, dispersion relation, and optical bandgap were systematically studied by means of various state of the art characterization methods. The dispersion spectra and the indirect optical bandgap of the heterostructures depend on the ratio of the two oxides, while the bandgap is very sensitive to the thicknesses of the barrier and quantum well layers. A significant blue shift of the absorption edge has been obtained by decreasing the TiO2 (quantum well) thickness down to about 0.5 nm. This study unfolds the possibility of achieving quantizing effects using dielectric heterostructures enabled by the control of layer thickness and properties down to an atomic scale. Furthermore, a unique combination of metal-dielectric heterostructure using Ir and Al2O3 are introduced. Their structural-property relationships were determined by various spectroscopic and microscopic techniques. Precisely tuning the ratio of the constituents provided by the ALD technology ensures the tailoring of the dispersion spectra along with a transition from effective dielectric to metallic heterostructures. Following this, the development of epsilon-near-zero metamaterials with tunable dielectric constants was explored by precisely varying the composition ratio of such heterostructures. The impact of such heterostructures in nonlinear optical processes, such as, second harmonic generation has also been examined. Altogether, this Dissertation enables a path towards atomic scale processing of tailored heterostructures demonstrating an extension of the material basis available for novel optical functionalities

Der Missbrauch einer kollektiven marktbeherrschenden Stellung in der digitalen Wirtschaft

Mehrere Unternehmen können auf einem Markt gemeinsam eine marktbeherrschende Stellung innehaben. Diese kollektive Marktbeherrschung kann den Anknüpfungspunkt für eine kartellrechtliche Kontrolle dieser Unternehmen bilden. Die kollektive Marktbeherrschung steht in einem Zusammenhang mit dem „Oligopolproblem“, das Juristen und Ökonomen seit langem beschäftigt. Das Oligopolproblem bezieht sich darauf, dass die oligopolistische Marktstruktur und der daraus resultierende wirtschaftliche Zwang die Oligopolmitglieder in die Lage versetzen, ein kartellähnliches wettbewerbsbeschränkendes Ergebnis zu erzielen, ohne dass eine Vereinbarung oder ein abgestimmtes Verhalten erforderlich ist (stillschweigende Kollusion). Die Märkte der digitalen Wirtschaft weisen oftmals nur schwer umkehrbaren Trend zur Konzentration auf, was insbesondere auf Netzwerkeffekte, Vorteile der Datenaggregation und Großfusionen zurückzuführen ist. Unternehmen in der digitalen Wirtschaft, insbesondere digitale Plattformen, können von positiven Netzwerkeffekten profitieren und so ihre bereits erlangte Marktmacht selbst verstärken. Infolgedessen haben sich die digitalen Märkte in vielen Fällen auf ein oder wenige große Unternehmen gekippt. Das Oligopolproblem ist also auch auf den Märkten der digitalen Wirtschaft zu erwarten. Wettbewerbsbeschränkungen durch Oligopole aufgrund hochintelligenter Algorithmen, großer Datenmengen und der Gatekeeper-Eigenschaften von Plattformen können sogar noch schädlicher werden. Die vorliegende Arbeit untersucht und analysiert die Anwendung des Wettbewerbsrechts in der Europäischen Union, der Bundesrepublik Deutschland und Volksrepublik China auf die Feststellung einer kollektiven Marktbeherrschung und deren Missbrauch, insbesondere unter Berücksichtigung der Besonderheiten der digitalen Wirtschaft

Practical examples of simulation-based load planning and control of personnel deployment in the assembly department

The shortage of skilled workers and the increasing aging of European society make it necessary to deploy qualified but performance-impaired employees in assembly in such a way that the load is tolerable and does not lead to absences. To be able to determine the load on an assembly employee, it is necessary not only to consider the aspects for determining the physical and psychological effects of activities on the individual, but also to record the load profile as accurately as possible. Practical examples are used to show how load-oriented personnel deployment can be supported by simulation during planning and control during operation

"We have switched." - Uncertainty and loss of trust in the Hungarian media

This essay approaches the issue of trust in the Hungarian media from the perspective that the last decade or so has brought constant and unpredictable changes in the media system. We argue that these changes were motivated solely by party politics linked to the Hungarian prime minister Viktor Orbán and were not market-driven at all. In effect, the owners of some media outlets and their worldviews have been undergoing rapid and radical changes. The essay illustrates these changes with specific examples and shows how this leads to a severely negative self-evaluation of journalism and a total loss of trust on the part of the public

Disentangling individual biases in jury voting: an empirical analysis of voting behavior in the Eurovision Song Contest

The Eurovision Song Contest is one of the worldwide biggest live media events and the world’s leading broadcast of an international music competition. The countries of the European Broadcasting Union participate by sending an artist (or a group of artists) to the contest and both expert juries and the television audience of all participating countries vote in a special ranking and points system to determine the eventual winner. A substantial list of cultural economics papers empirically analyzed the voting behavior of juries (consisting of music industry professionals) and audiences to identify voting biases because of cultural and political influences on the voting bodies. Due to limited data availability, this literature suffered from having to treat the national juries as a black box even though they are composed of individuals with different demographic characteristics (age, gender, etc.) and expert backgrounds (industry managers, musicians, composers, music journalists, etc.). Our analysis benefits from utilizing new data about each individual member of the jury including their role within the jury (e.g., the chairperson) as well as about their individual votes in the ESC. Therefore, for the first time, we can disentangle the voting behavior of the juries and track the voting behavior of individual jury members. Based upon a rich dataset including personal characteristics (gender, age, career/professional background, nationality, cultural heritage, etc.) of both jury members (voters) and performing artists in the contest (voting objects), we analyze whether the increasing similarity between voter (jury member) and voting object (contest performer) correlates with upward biases in terms of awarded points. In doing so, we employ the concept of Mahalanobis distance to measure similarity and employ modern econometric regression methods to derive our results. Inter alia, we identify conditions under which the similarity of jury members with contestants leads to a pro-bias in voting (across different countries). Interestingly, the professional background of jury members also significantly influences the individual voting bias, for instance, experts with classical music backgrounds display significantly less bias than presenters of radio or television programs or music journalists. Altogether, our analysis allows us to look beyond the hitherto dominating “country X is biased for/against country Y” conclusions and track voting biases on an individual level, based on personal characteristics

Biokompatibilität und antimikrobielle Wirkung von kaltem atmosphärischem Plasma

Alternative Behandlungsmethoden zu Antibiotika sind aufgrund der stetig steigenden mikrobiellen Resistenzen von großer Bedeutung. Kaltes atmosphärisches Plasma besitzt durch seine antimikrobiellen Eigenschaften und erwarteter guter Zellverträglichkeit ein hohes therapeutisches Potential. Angesichts der Variabilität der unterschiedlichen Plasmageräte ist die Prüfung der Biofunktionalität und Biokompatibilität jedes Typs essentiell. Erste Versuche zur Zellverträglichkeit eines gepulsten Plasmajets und einer DBD-Quelle wurden anhand von 2D-Zellkultur vergleichend durchgeführt sowie die antimikrobielle Wirkung in 2D analysiert. Hier zeigte sich eine stark schädigende Wirkung des Plasmas bei beiden Plasmageräten. Diese Art dieser Prüfung spiegelt in vivo Bedingungen nur ungenügend wider. Das Mittel der Wahl sind meist Tierversuche, beispielsweise an Mäusen. Daher erfolgte die Testung der Plasmageräte am 3D-Hautmodell. Die DBD-Quelle wies dabei die bessere Biokompatibilität auf sowie eine sehr gute antimikrobielle Wirkung und wurde daher für weitere Testungen verwendet. Für die Untersuchung der antimikrobiellen Wirkung in 3D-Umgebung wurde ein 3D-Modell für kutane Candidose etabliert. Die DBD-Quelle zeigte dabei einen guten antimikrobiellen Effekt. Anhand dieses 3D-Haut- und Infektionsmodells kann zukünftig eine anwendungsnahe Beurteilung der Effektivität und Verträglichkeit von Plasmageräten erfolgen um somit die Erforschung der Plasmawirkung grundlegend zu unterstützen

Doing Diversity of, in and with Media: Challenges and Potentials

Diversity is understood and practiced differently in different contexts. This essay does not focus on the question of what diversity is, but - influenced by the work of British scholar Sara Ahmed - explores what diversity ‘does’ or what we ‘do’ and ‘can do’ with diversity. Initially, the essay will address the current state of diversity and how diversity has become integrated into a ‘performance and audit culture’. This integration can lead to practices where diversity policies within institutions are managed as a form of capital, while the actual inequalities and the need for their rectification fade into the background. The essay will also discuss the impact of diversity on individuals who embody it. Subsequently, the essay will shift its focus towards the act of engaging with diversity in media, both within media platforms and through media usage. To better understand the complex, context-dependent and ambiguous nature of diversity work within the media, the essay will explore the key criteria of critical diversity literacy developed by South African researcher Melissa Steyn