Open Access

The requirements for the design of information and assistance systems in labour-intensive processes are interdisciplinary and have not yet been sufficiently addressed in research. This dissertation analyses, evaluates and describes possibilities for increasing the effectiveness and efficiency of labour-intensive processes through design-optimised socio-technical systems. The work thus contributes to further developing information and assistance systems for industrial applications and use in healthcare. The central dimensions of people, activity, context and technology are the focus of the scientific investigations following the Design Science Research paradigm. Design principles derived from this, a corresponding taxonomy, and a conceptual reference model for the design of socio-technical systems are the results of this dissertation.

This cumulative dissertation "Corporate Social Responsibility (CSR) Communication: Four empirical studies on the German banking industry" presents how commercial banks in Germany communicate their ambitions and commitment regarding corporate responsibility - i.e., CSR. The results of the first article show that the quality of mandatory non-financial reporting needs to be improved and that certain characteristics (e.g., previous reporting experience, reporting format and standard) have a positive influence on reporting quality. The second article shows that the CSR reporting scope on bank websites also has room for improvement and that various banking characteristics such as size, capital market orientation, media visibility or public ownership have an influence on communication. The third article illustrates that credit institutions in Germany are increasingly using social media for CSR communication, but that CSR communication strategies differ (Facebook vs. Twitter). The fourth article discusses CSR communication using advertisements and shows that the conceptual design of advertisements should be in line with the credit institution's business model and is therefore beneficial.

The computational analysis and the optimization of transport and mixing processes in fluid flows are of ongoing scientific interest. Transfer operator methods are powerful tools for the study of these processes in dynamical systems. The focus in this context has been mostly on closed dynamical systems and the main applications have been geophysical flows. In this thesis, we consider transport and mixing in closed flow systems and in open flow systems that mimic technical mixing devices. Via transfer operator methods, we study the coherent behavior in closed example systems including a turbulent Rayleigh-Bénard convection flow and consider the finite-time mixing of two fluids. We extend the transfer operator framework to specific open flows. In particular, we study time-periodic open flow systems with constant inflow and outflow of fluid particles and consider several example systems. In this case, the transfer operator is represented by a transition matrix of a time-homogeneous absorbing Markov chain restricted to finite transient states. The chaotic saddle and its stable and unstable manifolds organize the transport processes in open systems. We extract these structures directly from leading eigenvectors of the transition matrix. For a constant source of two fluids in different colors, the mass distribution in the mixer and its outlet region converges to an invariant mixing pattern. In parameter studies, we quantify the degree of mixing of the resulting patterns by several mixing measures. More recently, network-based methods that construct graphs on trajectories of fluid particles have been developed to study coherent behavior in fluid flow. We use a method based on diffusion maps to extract organizing structures in open example systems directly from trajectories of fluid particles and extend this method to describe the mixing of two types of fluids.

New media and digital technologies open up numerous possibilities to document different versions of reality, which makes it essential to examine how they transform the logic behind the creation and production of documentaries in digital cultures. The goal of this study is to inves-tigate the integration between the traditional documentary and new media: the interactive doc-umentary, in the context of the different sociocultural and technological environments of China and the West. Accordingly, a comparative study on the evolution and integration of these two fields was carried out. The documentary genre brings with it a method of classification and various modes of representing reality, while new media provide new approaches to interactivity as well as the production and distribution of interactive documentaries. In this context, the study examines the differences and characteristics of interactive documentaries in China and the West. Interactive documentaries grow and change as a continuously evolving system, engaging the roles of the author and the user, such that their roles are mixed for better co-expression and the reshaping of their shared environment. In addition, an analytical approach based on the types of interactivity was adopted to explore this new form of documentary both to deduce how the stories about our shared world can be told and to understand the impact of interactive doc-umentaries on the construction of our versions of the reality as well as our role in it.

Depressive disorders are highly prevalent mental disorders associated with an enormous individual and societal burden. The efficacy of both; treatment and prevention of depression have been meta-analytically demonstrated. Over the past two decades, an increasing number of internet-based interventions for depression has been developed and their efficacy was also metaanalytically shown. However, the uptake of such interventions – despite all the suggested advantages of internet-based interventions – is still rather low. The stigma still associated with “depression” may be one major barrier also to internet-based interventions. To overcome this barrier and potentially increase uptake, the paradigm of indirect interventions has been proposed recently. Indirect interventions primarily address common mental health problems, which are presumed to be less stigmatizing, and are suggested to reduce depressive symptoms indirectly. Targeting common mental health problems that are transdiagnostic risk factors for depression and other mental disorders – such as stress or repetitive negative thinking – seems especially promising. This dissertation evaluated the efficacy of three different internet-based interventions that can be regarded as indirect interventions to reduce depression since they primarily targeted risk factors for depression. For this purpose three registered randomized controlled trials were conducted. In addition to assessing the efficacy of the interventions regarding the primary outcomes, the efficacy to reduce depression and further secondary outcomes was studied. In Study I (N = 200) the efficacy of an internet-based stress management intervention (iSMI), which was adapted and tailored to career starting teachers, was compared to a waitlist control group (WLG). The participants of the intervention group (IG) reported significant reductions on the primary outcome perceived stress at post-intervention (T2), ΔWLG-IG = 3.5, d = 0.52, 95% CI [0.24, 0.80], and threemonth follow-up (3-MFU), d = 0.49, 95% CI [0.21, 0.77]. Furthermore, it was shown that the intervention indirectly also reduced depression at T2, d = 0.66, 95% CI [0.38, 0.94], and 3-MFU, d = 0.47, 95% CI [0.19, 0.75], nad produced significant clinically meaningful reductions of depression with a number needed to treat (NNT) of 3.9 at T2. The effects were sustained at an extended 6-MFU. Besides efficacy, the feasibility to complement the iSMI with a newly developnedte rinet-based classroom management training was shown. Moreover, mediation analyses corroborated the role of problem- and emotion-focused coping skills in the intervention’s effect on stress and the indirect effect of the intervention on depression through stress. Study II (N = 262) demonstrated the efficacy of an internet- and app-based gratitude intervention on the reduction of primary assessed repetitive negative thoughts at T2, ΔWLG-IG = 6.6, d = 0.61, 95% CI [0.36, 0.86], and 3-MFU, d = 0.75, 95% CI [0.50, 1.00], as compared to a WLG. The participants of the IG also reported significantly reduced depressive symptoms at T2, d = 0.38, 95% CI [0.13, 0.62], and 3-MFU, d = 0.40, 95% CI [0.15, 0.64], with significant clinically meaningful effects with an NNT of 4.3 at T2. The effects were sustained at an extended 6-MFU. Besides efficacy, mediation analyses showed that repetitive negative thinking mediated the gratitude intervention’s effect on depression. Finally, Study III N( = 351) showed that an interneta-sbed intervention, tackling worries at the beginning of the COVID-19 pandemic, was effective as compared to an active mental health advice group. At T2, two weeks after randomization, the IG reported significantly reduecveedl sl on the primary outcome worry as compared to controΔlsW, LG-IG = 5.0, d = 0.38, 95% CI [0.17, 0.59]. Participants of the IG also reported significantly reduced levels of depression at T2, d = 0.47, 95% CI [0.26, 0.68], with significant clinically meaningful reductions with an NNT of 3.6. The extended follow-ups in the IG indicated that the improvements from baseline were sustained until the 2-MFU and the 6-MFU. In a mediation analysis, worry was shown to mediate the intervention’s effect on depression. Across all three studies a reliable deterioration of depression was occasionally observed ranging from 3% to 5% in the IGs and from 5% to 12% in the control groups at T2. In summary, the studies in this dissertation demonstrated the efficacy of various indirect interventions focusing on rather common psychological problems to indirectly reduce depressive symptoms. The extent to which depression severity could be reduced is comparable to reductions found within participants with comparable baseline depression severity, in internetbased interventions directly addressing depressive symptoms. Indirect interventions are suggested to increase the uptake of interventions that reduce depressive symptoms, since they might be perceived as less stigmatizing and might broaden the range of interventions to choose from. Future research needs to compare indirect interventions for depression with direct interventions in head-to-head studies regarding uptake, efficacy and potential harmful effects. The indirect interventions examined in this dissertation could then complement the existing range of care for depression and thereby contribute to a reduction of the treatment gap and the burden of disease associated with depression.