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Institut
- Fakultät Nachhaltigkeit (11)
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- Institut für Management und Organisation (IMO) (4)
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Drum-Machines sind spätestens seit den 80er Jahren allgegenwärtige Taktgeber aktueller musikalischer Gestaltung. Die kleinen, unscheinbaren Boxen, in denen sich Schlagzeug-Pattern programmieren lassen, haben bisher allerdings kaum wissenschaftliche Aufmerksamkeit erhalten. Hier werden erstmals nicht nur die verwobenen Technik- und Kulturgeschichte(n) dieser Maschinen skizziert, sondern die Geräte selbst werden als Wissensobjekte ernst genommen. Ihr Sound und ihre neuen technikkulturellen Zeitlichkeiten, entworfen durch Breakbeat- und Pattern-Labore des HipHop, House und Techno, lässt die Geradlinigkeit historischer Narrative selbst Geschichte werden. Sie werden als Akteure klanglicher Zukünftigkeit gehört – treffend benannt mit einem Begriff Kodwo Eshuns als "Futurhythmaschinen".
Bestrebungen, tertiäre Ausbildungsgänge im Bereich Populärer Musik zu innovieren, sollten auf einem vertieften Verständnis des Berufsfelds basieren. Diese Prämisse setzt wiederum empirische Befunde zu den vorherrschenden Tätigkeitsprofilen sowie den entsprechenden Herausforderungen und maßgeblichen beruflichen Kompetenzbeständen voraus. Im Rahmen dieser Dissertationsschrift wurden daher zunächst die zentralen Aspekte berufsvorbereitender Popausbildungsprogramme und des Berufsmusikerarbeitsmarkts in Deutschland betrachtet, um im Anschluss Erkenntnisse zu prototypischen berufsfeldspezifischen Anforderungen zu präsentieren. Zentrale Forschungsfrage der Arbeit war dabei, an welchen Parametern eine berufspropädeutische Ausbildung im Bereich Populärer Musik ausgerichtet sein sollte, um angehenden Berufsmusikern den Erwerb einer zukunftsfähigen Kompetenzarchitektur zu ermöglichen. Zur Beantwortung dieser Frage kam ein methodenintegratives Verfahren zum Einsatz, wobei zunächst eine quantitative Vorstudie (Online-Fragebogen) durchgeführt wurde. Die Stichprobe (n=159) enthielt Alumni von künstlerischen bzw. künstlerisch-pädagogischen Ausbildungsgängen in Deutschland. Darauf folgte eine qualitative Hauptstudie, im Zuge derer halbstrukturierte Experteninterviews durchgeführt wurden. Das Sample umfasste Alumni von unterschiedlichen tertiären Ausbildungsgängen (n=9) sowie Experten aus dem Bereich Ausbildung (n=5) und Arbeitsmarkt (n=4). Die Daten wurden mittels qualitativer Inhaltsanalyse ausgewertet. Es zeigte sich zunächst, dass Ausbildungsgänge im Bereich Popmusik, insbesondere solche an musikhochschulischen Einrichtungen, einen starken Fokus auf musikalisch-künstlerische Inhalte legen, während sie Defizite im Bereich Professionalisierung und Berufsfeldorientierung aufweisen. Dies ist insofern im Hinblick auf die Berufspropädeutik problematisch, als die empirischen Daten deutlich machen, dass es gerade auch außermusikalische Kompetenzen sind, die von den Probanden als überaus bedeutsam für den Erfolg im Berufsfeld erachtet werden. Des Weiteren sind die Lernwege von Popmusikern im Vergleich zu Kollegen im Bereich europäischer Kunstmusik sehr heterogen. So zeigt sich eine Kombination aus informellem und formellem Lernen in mehr oder weniger formalen Lernsettings. Informelles Lernen geschieht dabei häufig in Form von Peer-Learning und autodidaktischem Lernen. Auch die Tätigkeitsportfolios der Befragten sind vielschichtig. Sie umfassen neben diversen musikalisch-künstlerischen vor allem pädagogische sowie musiknahe administrative und unternehmerische berufliche Aktivitäten. In einzelnen Fällen werden diese durch außermusikalische Tätigkeiten ergänzt. Ziel ist nicht die fortwährende Erwerbstätigkeit an einem bestimmten Arbeitsplatz, sondern die fortwährende Erwerbsfähigkeit in verschiedenen Teilbereichen des Berufsfelds. Ein wiederkehrendes Motiv in den Aussagen der Befragten sind die vielschichtigen Herausforderungen auf dem Musikerarbeitsmarkt. Darüber hinaus berichten die Probanden generell von fordernden Rahmenbedingungen wie u. a. einer häufig prekären Einkommenssituation, einer hohen Arbeitsbelastung sowie Schwierigkeiten eine nachhaltige Künstlerkarriere aufzubauen. Im Zuge der qualitativen Erhebung zeigt sich darüber hinaus, dass einige der Befragten über eine hohe Stressbelastung klagen, die in manchen Fällen zu psychischen Erkrankungen geführt hat. Dementsprechend scheint es wichtig Aspekte der physischen und mentalen Selbstfürsorge in die Ausbildung angehender Berufsmusikern zu implementieren. Die Kultivierung von Achtsamkeit wird in diesem Kontext als möglicher Weg zur Stressprophylaxe und Salutogenese präsentiert. Auf den Ergebnissen der Untersuchungen fußend wird am Ende der Arbeit ein achtsamkeitsbasiertes, integriertes Modell zur curricularen Gestaltung von Popmusikausbildungsgängen vorgestellt. Dieses berücksichtigt die Dimensionen Ganzheitlichkeit, Individualisierung, Berufsfeld- und Praxisorientierung, Vernetzung sowie Selbstfürsorge und kann als Matrix in Hinblick auf ein holistisch orientiertes und berufsfeldoptimiertes Ausbildungsgeschehen herangezogen werden. Es ist davon auszugehen, dass dessen praktische Umsetzung aufgrund der Berücksichtigung aktueller Tätigkeitsprofile und berufsfeldspezifischer Herausforderungen sowie der individuellen Dispositionen, Lernwege und Bedürfnisse der Akteure das Potenzial besitzt, den Absolventen zu einer verbesserten Erwerbsfähigkeit und beruflichen sowie persönlichen Zufriedenheit zu verhelfen.
In this dissertation, advanced nonlinear control strategies and nonlinear minimum-variance observation are combined, in order to improve the estimation and/or tracking quality within control and fault detection tasks, for several types of systems from the fields of electromobility and conventional drivetrain technology that have some potential for sustainability or performance improvements. The application-specific innovations in terms of nonlinear Kalman filter methods are: (1) Improved state of charge estimation for Lithium-ion battery cells, powered by a novel self-adaptive EKF that uses a high-order polynomial curve fit as a decomposition of the uncertain nonlinear output equation with intentionally redundant bases, and with a reduced number of polynomial parameters that are adapted online by the EKF itself. (2) Online estimation of the time delay between two periodic signals of roughly the same shape that have pronounced uncorrelated noise, based on a fractional-order approximation of the transcendent transfer function of the time delay which is used as a model in a novel kind of EKF. (3) Using two (E)KFs (one for the linear subsystem and one for the nonlinear subsystem of a new kind of multi-stage piezo-hydraulic actuator) in a cascaded loop structure in order to reduce the computation load of the estimation, by appropriate 'interfacing' between the two observers (using one shared system model equation, among other aspects). - The innovations in terms of nonlinear control methods are powered by observation, as well: (1) Sliding mode velocity control of a DC drive that is subject to nonlinear friction and unknown load torques, enhanced by an equivalent control law, and with a new intelligent switching gain adaptation scheme (for reduced control chattering and, thus, less energy consumption and actuator wear), which is powered by Taylor-linearized model predictive control, which in turn requires observer-based disturbance compensation (by a KF with a double-integrator disturbance model) for model-matching purposes in order to function correctly. (2) Direct speed control of permanent-magnet three-phase synchronous motors that have a high power-to-volume ratio, based on sliding mode control in a rotating d,q coordinate system, with a new equivalent control method that exploits both system inputs and with a secondary sliding surface to ensure compliance with the current-trajectory of maximum efficiency for the required torque, and which works without measurement of the rotor angle (thanks to a new kind of EKF that estimates all states in the stationary α,β coordinate system, as well as the disturbance/load torque and its derivative). In all instances, improvements (compared to methods existing in the literature) in terms of control and estimation performance have been achieved and confirmed using simulation studies or real experiments.
Analysis of User Behavior
(2020)
Online behaviors analysis consists of extracting patterns from server-logs. The works presented here were carried out within the "mBook" project which aimed to develop indicators of the quantity and quality of the learning process of pupils from their usage of an eponymous electronic textbook for History. In this thesis, the research group investigates several models that adopt different points of view on the data. The studied methods are either well established in the field of pattern mining or transferred from other fields of machine learning and data mining. The authors improve the performance of archetypal analysis in large dimensions and apply it to unveil correlations between visibility time of particular objects in the e-textbook and pupils' motivation. They present next two models based on mixtures of Markov chains. The first extracts users' weekly browsing patterns. The second is designed to process essions at a fine resolution, which is sine qua non to reveal the significance of scrolling behaviors. The authors also propose a new paradigm for online behaviors analysis that interprets sessions as trajectories within the page-graph. In this respect, they establish a general framework for the study of similarity measures between spatio-temporal trajectories, for which the study of sessions is a particular case. Finally, they construct two centroid-based clustering methods using neural networks and thus lay the foundations for unsupervised behaviors analysis using neural networks.
The wide accessibility of the Internet and web-based programs enable an increased volume of online interventions for mental health treatment. In contrast to traditional face-to-face therapy, online treatment has the potential to overcome some of the barriers such as improved geographical accessibility, individual time planning, and reduced costs. The availability of clients' treatment data fuels research to analyze the collected data to obtain a better understanding of the relationship among symptoms in mental disorders and derive outcome and symptom predictions. This research leads to predictive models that can be integrated into the online treatment process to assist clinicians and clients. This dissertation discusses different aspects of the development of predictive modeling in online treatment: Categorization of predictive models, data analyses for predictive purposes, and model evaluation. Specifically, the categorization of predictive models and barriers against the uptake of mental health treatment are discussed in the first part of this dissertation. Data analysis and predictive modeling are emphasized in the second part by presenting methods for inference and prediction of mood as well as the prediction of treatment outcome and costs. Prediction of future and current mood can be beneficial in many aspects. Inference of users' mood levels based on unobtrusive measures or diary data can provide crucial information for intervention scheduling. Prediction of future mood can be used to assess clients' response to the treatment and expected treatment outcome. Prediction of the expected treatment costs and outcomes for different treatment types allows simultaneous optimization of these objectives and to increase the cost-effectiveness of the treatment. In the third part, a systematic predictive model evaluation incorporating simulation analyses is demonstrated and a method for model parameter estimation for computationally limited devices is presented. This dissertation aims to overcome the current challenges of predictive model development and its use in online treatment. The development of predictive models for varies data collected in online treatment is demonstrated and how these models can be applied in practice. The derived results contribute to computer science and mental health research with client individual data analysis, the development ofpredictive models, and their statistical evaluation.
The dissertation contains four journal articles which are embedded within a framework manuscript that interconnects the individual articles and provides relevant background information. The dissertation's overall objective is to provide a multilayered and critical in-depth engagement with the timely phenomenon of integrated reporting (IR), a new reporting concept that is envisaged to revolutionize firms' present reporting infrastructure. While extant corporate reports (e.g., annual financial- and CSR report) often are criticized for being disconnected and to suffer from a lack of coherence, IR intends to provide all information that is material to a firm's short-, medium- und long-term value creation within one single, succinct document. To contribute to a set of previously defined relevant research gaps in literature, the dissertation makes use of a combined empirical-quantitative and explorative-qualitative research design. The first article entitled investigates a set of different IR-, corporate governance and financial accounting-specific factors that are expected to determine European and South African firms' materiality disclosure quality. To this purpose, an original, hand-collected materiality disclosure score was developed. The second article explores IR perceptions of SME managers that have not embarked on IR, but are potential candidates to do so in future. Based on a review of extant literature, the article develops a theoretical framework to subsequently discuss motives for and barriers to IR adoption. The critical discussion contributes to the academic debate on incentives for and barriers to voluntary IR adoption. The third article investigates whether voluntary IR adoption among European firms is associated with lower cost of public debt. While earlier studies suggest that IR leads to lower information asymmetries, increases analyst forecasts, and decreases cost of equity, corresponding evidence for the debt market is largely missing. Subsequent analyses test as to whether such an association is even more pronounced by a firm's environmental, social and governance (ESG) performance or its belonging to an environmentally sensitive industry. The fourth article uses an experimental design to investigate nonprofessional investors' reactions to an IR assurance. To this purpose, two separate experiments with two different groups of nonprofessional investors were carried out: one with Masters students and one with managers of large corporations. Results help to answer the question as to whether an IR assurance as well as its determinants, namely the assurance provider and the assurance level, affect nonprofessional investors' financial decision-making. In the second step, subsequent in-depth interviews reveal an IR assurance-critical attitude among managers, who draw upon their practical experience with assurance engagements.
It is understood among research and policy makers that addressing unsustainable individual consumption patterns is key for the vision of sustainable development. Education for Sustainable Consumption (ESC) is attributed a pivotal role for this purpose, aiming to improve the capacity of individuals to connect to and act upon knowledge, values and skills in order to respond successfully and purposefully to the demands of sustainable consumption. Yet despite political, scientific, and educational efforts and increasing awareness in the general population, little has been achieved to substantially change behavioral patterns so far. As part of the explanation for this shortcoming, it has been argued that current ESC practices have neglected the personal dimension of sustainable consumption, especially the affective-motivational processes underlying unsustainable consumption patterns. Against this background, this cumulative thesis is guided by the question how personal competencies for sustainable consumption can be defined, observed, and developed within educational settings. Special attention is given to mindfulness practices, describing the practice of cultivating a deliberate, unbiased and openhearted awareness of perceptible experience in the present moment. Drawing upon an explorative, qualitative research methodology, the thesis looks at three different mindfulness-based interventions aiming to stimulate competencies for sustainable consumption, reaching out to a total number of 321 participants (employees and university students). In this thesis, the author suggests to define personal competencies for sustainable consumption as abilities, proficiencies, or skills related to inner states and processes that can be considered necessary or sufficient to engage with sustainable consumption (SC). These include ethics, self-awareness, emotional resilience, selfcare, access to and cultivation of personal resources, access to and cultivation of ethical qualities, and mindsets for sustainability. The thesis holds that the observation of personal competencies benefits from a combination of different methodological and methodical angles. When working with self-reports as empirical data, a pluralistic qualitative methods approach can help overcoming shortcomings that are specifically related to individual methods while increasing the self-reflexivity of the research. Moreover, it is suggested to let learners analyze their own personal statements in groups, applying scientific methods. The products of the group analyses represent data based on an inter-subjectively shared perspective of learners that goes beyond self-estimation of personal competencies. In terms of developing personal competencies for SC, it can be concluded that mindfulness practice alone is not sufficient to build personal competencies for SC. While it can stimulate generic personal competencies, individuals do not necessarily apply these competencies within the domain of their consumption. Nevertheless, mindfulness practice can play an important role in ESC, insofar as it lays the inner foundation to engage with sustainability-related issues. More precisely, it allows learners to experience the relevance of their inner states and processes and the influence they have on actual behaviors, leading to a level of selfawareness that would not be accessible solely through discursive-intellectual means. Furthermore, participants experience mindfulness practice as a way to develop ethical qualities and access psychological resources, entailing stronger emotional resilience and improved well-being. In order to unleash its full potential for stimulating personal competencies for SC, however, the findings of the thesis suggest that mindfulness practice should be (a) complemented with methodically controlled self-inquiry and (b) related to a specific behavioral change. In this vein, self-inquiry-based and self-experience-based learning – two pedagogical approaches developed during the period of research for this thesis – turned out to be promising pedagogies for educational settings striving to stimulate the development of personal competencies for SC.
Thermal energy storage systems have a high potential for a sustainable energy management. Low temperature thermochemical energy stores based on gas-solid reactions represent appealing alternative options to sensible and latent storage technologies, in particular for heating and cooling purposes. They convert heat energy provided from renewable energy and waste heat sources into chemical energy and can effectively contribute to load balancing and CO2 mitigation. At present, several obstacles are associated with the implementation in full-scale reactors. Notably, the mass and heat transfer must be optimized. Limitations in the heat transport and diffusions resistances are mainly related to physical stability issues, adsorption/desorption hysteresis and volume expansion and can impact the reversibility of gas-solid reactions. The aim of this thesis was to examine the energy storage and cooling efficiency of CaCl2, MgCl2, and their physical salt mixtures as adsorbents paired with water, ethanol and methanol as adsorbates for utilization in a closed, low level energy store. Two-component composite adsorbents were engineered using a representative set of different host matrices (activated carbon, binderless zeolite NaX, expanded natural graphite, expanded vermiculite, natural clinoptiolite, and silica gel). The energetic characteristics and sorption behavior of the parent salts and modified thermochemical materials were analyzed employing TGA/DSC, TG-MS, Raman spectroscopy, and XRD. Successive discharging/charging cycles were conducted to determine the cycle stability of the storage materials. The overall performance was strongly dependent on the material combination. Increase in the partial pressure of the adsorbate accelerated the overall adsorbate uptake. From energetic perspectives the CaCl2-H2O system exhibited higher energy storage densities than the CaCl2 and MgCl2 alcoholates studied. The latter were prone to irreversible decomposition. Ethyl chloride formation was observed for MgCl2 at room and elevated temperatures. TG-MS measurements confirmed the evolution of alkyl chloride from MgCl2 ethanolates and methanolates upon heating. However, CaCl2 and its ethanolates and methanolates proved reversible and cyclable in the temperature range between 25°C and 500°C. All composite adsorbents achieved intermediate energy storage densities between the salt and the matrix. The use of carbonaceous matrices had a heat and mass transfer promoting effect on the reaction system CaCl2-H2O. Expanded graphite affected only moderately the adsorption/desorption of methanol onto CaCl2. CaCl2 dispersed inside zeolite 13X showed excellent adsorption kinetics towards ethanol. However, main drawback of the molecular sieve used as supporting structure was the apparent high charging temperature. Despite variations in the reactivity over thermal cycling caused by structural deterioration, composite adsorbents based on CaCl2 have a good potential as thermochemical energy storage materials for heating and cooling applications. Further research is required so that the storage media tested can meet all necessary technical requirements.
Panic disorder is a common anxiety disorder, which is associated with high subjective burden as well as a high cost for the health economy. According to the National Treatment Guideline S3, cognitive behavior therapy is recommended as the most effective psychological treatment. However, many people in need do not have access to cognitive behavior therapy. Internet-based interventions have proven to be an effective way to provide access to evidence-based treatment to those affected. For anxiety disorders, such as panic disorder and agoraphobia, a good effectiveness of internet-based interventions has been proven in numerous international studies. However, the internet has changed over the last few years: mobile technologies have considerable potential to further improve the adherence and effectiveness of internet-based interventions. Against this background, the authors developed the hybrid online training "GET.ON Panic". In this training, an app has been integrated into a browser-based online training. The app consists of a mobile diary for self-monitoring as well as a mobile exposure-guide that supports participants in self-exposure exercises in their everyday lives.In an initial exploratory feasibility study, qualitative interview data and quantitative measurements were collected in a pre-post design of 10 participants. Usage, user friendliness, user satisfaction and acceptance of the app were generally considered high. The use of interoceptive exposure exercises and daily summaries of anxiety and mood were the most widely performed and rated the best, while in vivo exposure exercises and the monitoring of acute panic symptoms were found to be difficult.In the efficacy study, 92 participants with mild to moderate panic symptoms were randomized into two parallel groups. After eight weeks, the intervention group showed a significant improvement in the severity of panic symptoms compared to the waiting control group. Using the intention-to-treat approach, a covariance analysis with baseline values as a covariate yielded a mean effect of Cohen's d=0.66 in reducing the panic symptoms in favor of the intervention group. This effect increased to d=0.89 after three months and stayed at d=0.81 at the 6-month measurement point. Response and remission rates were also significantly higher in the intervention group. This positive effect was also shown for secondary outcomes such as depressive symptoms and quality of life. A correlation between app usage and clinical outcomes could not be found. This work was the first to demonstrate that a hybrid online training based on cognitive behavior therapy is effective in reducing panic symptoms as well as panic disorder. In addition, this work contributes to a deeper understanding of the potential of mobile technologies in the field of e-mental health.
"Einfachheit" gehört zu den maßgeblichen Begriffen, mit denen in der Kunst-, Kultur- und Literaturgeschichte unterschiedliche Wertzuschreibungen einhergehen. Seit Ende des 20. Jahrhundert setzt sich nebenher ein globalisierter Lifestyle durch, der mit geschickten Werbetriggern eine "Sehnsucht nach Einfachheit" weckt und hohe Erwartungen an das Ideal der Komplexitätsbewältigung knüpft. Das damit einhergehende breite Funktionalisierungspotential wird hier aufgegriffen, um den neuen Fragen nachzugehen, warum die Einfachheit einen bemerkenswerten Erfolg in der deutschsprachigen Gegenwartsliteratur feiert und was uns vergleichbare Bewegungen in Architektur, Design und den visuellen Künsten über den aktuellen Ruf nach Einfachheit erzählen. Am Beispiel des erzählerischen Werks von Judith Hermann, Peter Stamm und Robert Seethaler wird erstmalig gefragt, mit welcher Intention und Qualität sich die Einfachheit in den Texten dieser Autoren formiert und ob es sich bei der Kunst der erzählerischen Reduktion um ein spezifisch für die Gegenwart relevantes Konzept handelt. Die Studie leistet damit einen wesentlichen Beitrag zu der noch ausstehenden literaturwissenschaftlichen Systematisierung einer "Ästhetik der Einfachheit".
This cumulative dissertation embraces four empirical papers addressing socio-economic issues relevant to policy-makers and society as a whole. These papers cover important aspects of human life including health at birth, life satisfaction, unemployment periods and retirement decisions. The analyses are carried out applying advanced econometric methods and are based on data sets consisting of survey data as well as administrative records. The first joint paper investigates the causal impact of prenatal exposure to air pollution on neonatal health in Italy in the 2000s combining detailed information on mother's residential location from birth certificates with PM10 concentrations from air pollution monitors. Variation in local weekly rainfall is exploited as an instrumental variable for non-random air pollution exposure. Using quasi-experimental variation in rainfall shocks allows to identify the effect of PM10, ruling out potential bias due to confounder pollutants. The paper estimates the effect of exposure for both the entire pregnancy period and separately for each trimester to test whether the neonatal health effects are driven by pollution exposure during a particular gestation period. This information enhances our understanding of the mechanisms at work and help prevent pregnant mothers from most dangerous exposure periods. Additionally, the effects of prenatal exposure to PM10 are estimated by maternal labor market status and maternal education level to understand how the pollution burden is shared across different population groups. This decomposition allows to identify possible mechanisms through which environmental inequality reinforces the negative impact of early-life exposure to air pollution. This study finds that average PM10 and days with PM10 level above the hazard limit reduce birth weight, gestational age, and measures of overall newborn health. Effects are largest for third trimester exposure and for low-income and less educated mothers. The second joint paper updates previous findings on the total East-West gap in overall life satisfaction and its trend by using data from the German Socio-Economic Panel for the years 1992 to 2013. Additionally, the effects are separately analyzed for men and women as well as for four birth cohorts. The results indicate that reported life satisfaction is, on average, significantly lower in East than in West German federal states and that part of the raw East-West gap is due to differences in household income and unemployment status. The conditional East-West gap decreased in the first years after the German reunification and remained quite stable and sizable since the mid-nineties. The results further indicate that gender differences are small. Finally, the East-West gap is significantly smaller and shows a trend towards convergence for younger birth cohorts. The third joint paper explores the effects of a major reform of unemployment benefits in Germany on the labor market outcomes of individuals with some health impairment. The reform induced a substantial reduction in the potential duration of regular unemployment benefits for older workers. This work analyzes the reform in a wider framework of institutional interactions, which allows to distinguish between its intended and unintended effects. The results based on routine data collected by the German Statutory Pension Insurance and a Difference-in-Differences design provide causal evidence for a significant decrease in the number of days in unemployment benefits and increase in the number of days in employment. However, they also suggest a significant increase in the number of days in unemployment assistance, granted upon exhaustion of unemployment benefits. Transitions to unemployment assistance represent an unintended effect, limiting the success of a policy change that aims to increase labor supply via reductions in the generosity of the unemployment insurance system. The fourth, single-authored paper explores how an increase in the early retirement age affects labor force participation of older workers. The analysis is based on a social security reform in Germany, which raised the early retirement age over several birth cohorts to boost employment of older people and ultimately alleviate the burden on the public pension system. Detailed administrative data from the Federal Employment Agency allow to distinguish between employment and unemployment as well as disability pensions and retirement benefits claims. Using a Regression Kink design in a quasi-experimental framework, the author shows that the raised early retirement age had positive employment effects and negative effects on retirement benefits claims. The results also show that some population groups are more sensitive to a reduction in retirement options and more likely to seek benefits from other government programs. In this respect, the author finds that workers in manufacturing sector respond to the raised early retirement age by claiming benefits from the disability insurance program designed to compensate for reduced earnings capacity due to severe health problems. The treatment heterogeneity analysis further suggests that high-wage workers are more likely to delay exits from employment, which is in line with incentives but might also indicate an increased inequality within the affected birth cohorts induced by the reform. Finally, women seem to rely on alternative sources of income such as retirement benefits for women, or spouse's or partner's income not observed in the data. All things considered, workers did not adjust to the increased early retirement age by substituting early retirement with other government programs but rather responded to the reform in line with the policy intent. At the same time, the findings point to heterogeneous behavioral responses across different population groups. This implies that raising the early retirement age is an effective policy tool to increase employment only among older people who have the real choice to delay employment exits. Therefore, reforms that raise statutory ages should ensure social support for workers only marginally attached to the labor market or not able to work longer due to potential health problems or other circumstances.
Educational research has shown that reflection and feedback are crucial for substantial development of pre-service teachers' professional competence. However, reflection and feedback sessions are not a standard element of teaching practicums due to time- and location-constraints. Digital practicum environments can lift these constraints. Digital reflection and feedback environments have typically applied either textual accounts or video sequences of classroom practice, with varying effects. Consequently, the studies presented in this cumulative dissertation are focused on how the use of text- or video-based digital reflection and feedback environments during a practicum influence specific components of pre-service teachers' professional competence (i.e., beliefs about teaching and learning, self-efficacy, professional vision of classroom management, feedback competence). All studies followed a quasi-experimental, pre-test-post-test design. Pre-service teachers at the fourth-semester bachelor level in a German university took part in the studies. Pre-service teachers participated in a four-week teaching practicum at local schools. During the teaching practicum, pre-service teachers were divided into five different groups. The control group (CG) took part in a traditional practicum with live observations and face-to-face reflection and feedback with peers and experts. Pre-service teachers of the intervention groups (IG 1, IG 2, IG 3, IG 4) reflected and received feedback in highly structured text- or video-based digital environments. Intervention groups 1 (IG 1) and 2 (IG 2) participated in a text-based digital reflection and feedback environment. While IG 1 participants only received feedback from peers, IG 2 pre-service teachers also received expert feedback. Intervention groups 3 (IG 3) and 4 (IG 4) took part in a video-based digital reflection and feedback environment. IG 3 pre-service teachers only received peer feedback, whereas IG 4 participants also received expert feedback. Mixed methods were applied by generating quantitative and quantitative-qualitative data was with questionnaires, a standardized video-based test and content analysis. The studies demonstrated that classroom videos and video-based digital reflection and feedback environments can effectively enhance pre-service teachers' professional competence. This finding can be predominantly attributed to two characteristics of the application in the digital reflection and feedback environments: (a) being able to revisit a multitude of authentic teaching situations without time pressure and (b) the degree of decomposition by deliberate, focused practice and scaffolding elements. Furthermore, expert feedback seemed to be of better quality and entailed more substantial effects than peer feedback. The results of the conducted studies on professional vision of classroom management, beliefs about teaching and learning and feedback competence showed that expert feedback can be seen as a lens reducing and focusing classroom complexity, enabling pre-service teachers to perceive crucial teaching situations that would have otherwise gone unnoticed and to benefit from expert modelling of high-quality feedback. Consequently, video-based digital reflection and feedback environments with expert feedback can significantly improve pre-service teachers' professional competence during teaching practicums and, thus, better prepare pre-service teachers for future classroom challenges, leading to better learning environments for school students.
Durch die Neufassung des § 68f Abs.1 Satz 1 StGB tritt die Führungsaufsicht bei vollverbüßter Strafe von zwei Jahren oder bei schwerwiegenden Taten gemäß § 181b StGB nach einem Jahr kraft Gesetzes ein. Diese Reform im Jahr 2007 hat zu einem enormen Anstieg von Führungsaufsichten nach vollverbüßter Jugendstrafe geführt. Die Regelungen und Aufgaben der Verantwortlichen der Führungsaufsicht nach Jugendstrafe sind vielfältig und anders als beispielsweise bei der Führungsaufsicht nach einer Maßregel der Besserung und Sicherung (gem. §§ 63f). Für die Arbeit mit straffälligen Jugendlichen und Heranwachsenden unter Führungsaufsicht nach vollverbüßter Jugendstrafe gibt es für die Justizsozialarbeitenden keine explizite Handreichung. Im Vordergrund der Arbeit liegt die Frage: Welche Faktoren können, aus Sicht der beteiligten Akteure, die Legalbewährung jugendlicher und heranwachsender Vollverbüßer unter Führungsaufsicht begünstigen? Die Praxisforschung wird anhand von 15 Interviews mit den Verantwortlichen der Führungsaufsicht dargestellt und nimmt Bezug auf das in der Praxis erprobte Modellprojekt RESI und das Lebenslagenkonzept.
Both sustainability and transdisciplinary research can change academic research, especially with regard to its relevance for, and relationship with, its environments. Transdisciplinary sustainability research (TSR), thus, offers the opportunity to change non-sustainable development paths of sciences themselves. In order to fully exploit this possibility, this PhD project addresses the question of how TSR, in the first place, does conceptualize and, in the second place, could conceptualize knowledge, research, and science. Firstly, this PhD project analyzes, from a discourse studies perspective, the term problem in TSR, against the background of discourses on sustainable development. Secondly, it explores the historical-analytical and transformative concept of the problematic. The results, firstly, show the consequences of a problem-solving focus for TSR, and secondly, differentiate it from a transformative direction of problematic designing, as a more appropriate view on the dimensions of transformation and their qualities of change that matter for TSR. This PhD project aims to contribute to a self-understanding of, and a philosophical communication about, TSR, as a research form in the sustainability sciences.
Existing institutions no longer appear to be sufficiently capable to deal with the complexity and uncertainty associated with the wicked problem of sustainability. Achieving the required sustainability transformation will thus require purposeful reform of existing institutional frameworks. However, existing research on the governance of sustainability of sustainability transformations has strongly focused on innovation and the more "creative" aspects of these processes, blinding our view to the fact that they go hand with the failure, decline or dismantling of institutions that are no longer considered functional or desirable. This doctoral dissertation thus seeks to better understand how institutional failure and decline can contribute productively to sustainability transformations and how such dynamics in institutional arrangements can serve to restructure existing institutional systems. A systematic review of the conceptual literature served to provide a concise synthesis of the research on "failure" and "decline" in the institutional literature, providing important first insights into their potentially productive functions. This was followed up by an archetype analysis of the productive functions of failure and decline, drawing on a wide range of literatures. This research identified five archetypical pathways: (1) crises triggering institutional adaptations toward sustainability, (2) systematic learning from failure and breakdown, (3) the purposeful destabilisation of unsustainable institutions, (4) making a virtue of inevitable decline, and (5) active and reflective decision making in the face of decline instead of leaving it to chance. Empirical case studies looking at the German energy transition and efforts to phase out coal in the Powering Past Coal Alliance served to provide more insights on (a) how to effectively harness "windows of opportunity" for change, and (b) the governance mechanisms used by governments to actively remove institutions. Results indicate that the lock-in of existing technologies, regulations and practices can throw up important obstacles for sustainability transformations. The intentional or unintentional destabilisation of the status quo may thus be required to enable healthy renewal within a system. This process required active and reflective management to avoid the irreversible loss of desirable institutional elements. Instruments such as "sunset clauses" and "experimental legislation" may serve as important tools to learn through "trial and error", whilst limiting the possible damage done by failure. Focusing on the subject of scale, this analysis finds that the level at which failure occurs is likely to determine the degree of change that can be achieved. Failures at the policy-level are most likely to merely lead to changes to the tools and instruments used by policy makers. This research thus suggests that failures on the polity- and political level may be required to achieve transformative changes to existing power structures, belief-systems and paradigms. Finally, this research briefly touches on the role of actor and agency in the governance of sustainabilitytransformations through failure and decline. It finds that actors may play an important role in causing a system or one of its elements to fail and in shaping the way events are come to be perceived.
Die vorliegende Dissertationsschrift orientiert sich an dem soziologischen Verständnis von Zeit als Gestaltungsprinzip (Elias 1984) und der damit verbundenen Bedeutung für institutionell-pädagogische Zeitgestaltungen. Im Rahmen einer qualitativen - und ethnografisch orientierten - Fallstudie wird herausgearbeitet, wie sich die kindlichen Zeitpraktiken in unterschiedlichen Institutionen der frühen Bildung und im Übergang zur Grundschule mit ihren je besonderen institutionellen Zeitordnungen ausprägen. Die empirischen Befunde zeigen, dass die Fach- und Lehrkräfte auf normierte Ablaufmuster und Vorgaben zur Zeitnutzung zurückgreifen und sich spezifischer Disziplinierungspraktiken bedienen, um die Kinder in die vorherrschende soziale Zeitordnung und das darin verwobene generationale Arrangement einzupassen. Verstärkt durch die zeitlichen Anforderungen des institutionellen Alltags verengen sich die erwachsenen Zeitpraktiken immer wieder zu den gleichen Handlungsweisen; insbesondere die Tendenzen zur Beschleunigung und Verdichtung sind als Gestaltungsmodi beobachtbar. Ungeachtet dessen verdeutlichen die Erkenntnisse weiterhin, dass sich die kindlichen Zeitpraktiken in Formen ausprägen, die häufig nicht den sozial vorherrschenden Handlungspraktiken und Handlungslogiken folgen, sondern vielmehr auf einer eigenen Sinngebung beruhen. Im Vergleich zu den Erwachsenen kommt diese zeitliche Eigenart dadurch zum Ausdruck, dass Kinder Gegenständen andere Bedeutungen und Funktionen beimessen, andere Formen des Handlungsvollzuges praktizieren und sich auch in je besonderen Geschwindigkeitsmodi bewegen. In ihrem spezifischen zeitlichen Handeln lassen sich die Kinder bewusst nicht von den Vorgaben zur Zeitnutzung stören bzw. unterwandern diese immer wieder auch zielgerichtet. Angesichts der divergierenden Handlungspraktiken von Erwachsenen und Kindern geht der Alltag mit regelhaften Zeitkonflikten einher, die sich zulasten der kindlichen Persönlichkeitsentwicklung, des Erwerbs von Zeitkompetenz wie auch der Arbeitsbedingungen des Personals auswirken können, weshalb eine weitere Intensivierung einschlägiger Zeitforschungen bedeutsam erscheint.
Es gibt bisher wenige empirische Modelle zum Flugzeugkabinenkomfort, und vereinzelt werden Umgebungsfaktoren wie Akustik, Turbulenzen, Temperatur und Luftqualität untersucht, aber kein Vorhersagemodell für den Gesamtkomfort existiert bislang. Ziel der Studie ist es, die Determinanten für das Komforterleben bzw. die Zufriedenheit in der Flugzeugkabine zu identifizieren. Dabei wird ein Methodenmix aus drei Datenerhebungen angewendet: (1) In der ersten Untersuchung werden zehn Flugzeugkabinenbilderpaare zehn Sekunden pro Bild präsentiert. Über die multidimensionale Skalierung wird auf einer fünfstufigen Skala die Ähnlichkeit von sehr bis gar nicht dargeboten. Die eindimensionale Darstellung der Bilder legt nahe, dass es einen Faktor wie "Platz zum Sitzen" gibt. In Interviews wird der Annahme nachgegangen. (2) In Interviews assoziierten 61 Psychologiestudierende Nomina zum Fliegen. Bei den Kategorien stellt Platz/Beinfreiheit der am häufigsten genannte Komfortaspekt innerhalb einer Flugzeugkabine dar. Sitzkomfort, Flugbegleiter, Inflight-Entertainment, Essen, Trinken, Sicherheit, Sauberkeit wurden oft genannt, Temperatur, Design, Toiletten, Geräusche, Turbulenzen, Geruch, Luftqualität, Beleuchtung, Raucherbereiche und ein gutes Preis-Leistungsverhältnis nur vereinzelt. (3) Die Fragebögen am Hamburger Flughafen greifen die in den Interviews genannten Komfortaspekte auf. 301 Passagiere beantworteten Zufriedenheitsitems auf einer fünfstufigen Skala. Mittels einer explorativen Faktorenanalyse werden fünf Faktoren aus den Items extrahiert, die räumliche, physiologische, psychologische, physikalische und organisatorische Aspekte beinhalten. Eine lineare multiple Regression mit den fünf Faktoren zum Item "Gesamtzufriedenheit" ist hochsignifikant und klärt 40,5% Varianz auf. Die Moderatoreinflüsse und Interaktionen werden teils signifikant und klären 1,6% weniger (Fluglänge) oder 1,5% mehr (Fluggesellschaft und Flugangst) Varianz auf. Mittelwertvergleiche zeigen, dass die Star Alliance Fliegenden und Nicht-Flugängstlichen bei allen fünf Faktoren und fast allen Items hochsignifikant höhere Zufriedenheitswerte als Billigfliegende und Flugängstliche aufweisen. Bei Kurz- über Mittel- zum Langstreckenflug wurde eine v-Form gefunden mit der geringsten Zufriedenheit bei Mittelstreckenflügen mit hochsignifikanten Unterschieden. Entscheidend ist das durch die Kombination aus Zusammenhangs- und Vorhersageanalyse für den Forschungsbereich "Komfort in der Flugzeugkabine" neu generierte Gesamtkomfortmodell.
Um das noch bestehende Reichweitenproblem von Elektrofahrzeugen zu lösen, sind Fahrzeugkonzepte wie Plug-in Hybridfahrzeuge sehr vielversprechend, sofern mit ihm überwiegend im Batteriebetrieb gefahren wird. Sie kombinieren die Vorteile des Verbrennungsmotors und des Elektromotors, sodass das lokale Emissionsproblem in Ballungszentren gelöst werden kann, ohne dass der Kunde dabei auf die Reichweite verzichten muss. Wenn das Fahrzeug allerdings überwiegend für Kurzstrecken genutzt wird, sind alterungsbedingte Veränderungen des Kraftstoffes möglich, da dieser länger im Tank verbleibt als üblich. In dieser Arbeit wird ein Konzept zur sensorischen Bestimmung der Qualität des Kraftstoffes vorgestellt. Hierzu wurde ein Prototyp entwickelt, in dem mithilfe des Real- und Imaginärteils der Permittivität alternde Kraftstoffe erkannt werden können. Dabei konnte durch das frequenzabhängige Permittivitätssignal des Sensors spezifisch zwischen nieder- und hochmolekularen Oxidationsprodukten in Kraftstoffen unterschieden werden. Da das Verbrennungs- und Emissionsverhalten des Motors von der Kraftstoffmischung vorgegeben ist, bietet eine zusätzliche sensorische Erfassung der Kraftstoffzusammensetzung weitere Optimierungspotenziale, um Emissionen zu reduzieren: So ist das Motormanagement im Fahrzeug zumeist auf Referenzkraftstoffe mit gleichbleibender Qualität abgestimmt. Variable Kraftstoffzusammensetzungen, die durch die Erdöllagerstätte und den zusätzlichen Konversionsverfahren zur Herstellung von fortschrittlichen Kraftstoffen vorgegeben sind, werden in dieser Anpassungsstrategie bisher nicht berücksichtigt. Als weitere Aufgabe wird in dieser Arbeit daher ein multisensorischer Ansatz verfolgt, wonach zusätzlich zur Kraftstoffalterung noch die Kraftstoffzusammensetzung erkannt werden kann. Insgesamt bietet die Sensorik das Potenzial zur kontinuierlichen Kraftstoffüberwachung in Plug-in Hybridfahrzeugen, um so einen Beitrag zum sicheren und nachhaltigen Betrieb solcher Fahrzeuge gewährleisten zu können.
As modern society progresses, waste treatment becomes a pressing issue. Not only are global waste amounts increasing, but there is also an unmet demand for sustainable materials (e.g. bioplastics). By identifying and developing processes, which efficiently treat waste while simultaneously generating sustainable materials, potentially both these issues might be alleviated. Following this line of thought, this dissertation focuses on procedures for treatment of the organic fraction of waste. Organic waste is a suitable starting material for microbial fermentation, where carbohydrates are converted to smaller molecules, such as ethanol, acetic acid, and lactic acid. Being the monomer of the thermoplastic poly-lactic acid, lactic acid is of particular interest with regard to bioplastics production and was selected as target compound for this dissertation. Organic waste acted as substrate for non-sterile batch and continuous fermentations. Fermentations were initiated with inoculum of Streptococcus sp. or with indigenous consortium alone. During batch mode, concentration, yield, and productivity reached maximum values of 50 g L−1, 63%, and 2.93 g L−1 h −1. During continuous operation at a dilution rate of 0.44 d−1, concentration and yield were increased to 69 g L−1 and 86%, respectively, while productivity was lowered to 1.27 g L−1 h −1 . To fully exploit the nutrients present in organic waste, phosphate recovery was analyzed using seashells as adsorbent. Furthermore, the pattern of the indigenous consortium was monitored. Evidently, a very efficient Enterococcus strain tended to dominate the indigenous consortium during fermentation. The isolation and cultivation of this consortium gave a very potent inoculum. In comparison to the non-inoculated fermentation of a different organic waste batch, addition of this inoculum lead to an improved fermentation performance. Lactic acid yield, concentration, and molar selectivity could be increased from 38% to 51%, 49 g L−1 to 65 g L−1, and 46% to 86%, respectively. Eventually, fermentation process data was used to perform techno-economic analysis proposing a waste treatment plant with different catchment area sizes ranging from 50,000 to 1,000,000 people. Economically profitable scenarios for both batch and continuous operation could be identified for a community with as few as 100,000 inhabitants. With the experimental data, as well as techno-economic calculations presented in this dissertation, a profound contribution to sustainable waste treatment and material production was made.
The present doctoral dissertations seeks to shed theoretical and empirical light on how complexity and different approaches to manage it affect perceptions, behaviors, and outcomes in integrative negotiations. Chapter 1 summarizes the following chapters, describes their individual contribution to the present thesis, and outlines avenues for future research. In Chapter 2, a theoretical model comprising of task- and context-based determinants of complexity in negotiations is developed. In Chapter 3, the effects of the number of issues (high vs. low) as one essential determinant of complexity on parties' trade-off behavior and joint outcomes are investigated in a series of four experiments. Furthermore, negotiators' cognitive categorizing of issues (i.e., their mental-accounting approach) is examined as the underlying psychological mechanism. Results reveal that more issues lead to a higher risk of scattering the integrative potential between cognitive categories (i.e., mental accounts), reducing trade-off quality and joint outcomes. In Chapter 4, the generalizability of the detrimental effect of the number of issues on joint outcomes is tested across varying numbers of issues in a meta-analysis. Moreover, boundary conditions for the effect are investigated. Results confirm the generalizability of the number-of-issues effect, but no relevant boundary conditions are identified. In Chapter 5, the effects of different mental-accounting approaches on negotiators' judgment accuracy, trade-off behaviors, and negotiation outcomes are examined in a series of five experiments. Results demonstrate that categorizing a moderate number of issues into each mental account leads to a higher judgment accuracy, trade-off quality, and joint outcomes, but only if negotiators manage to pool the integrative potential within these accounts. Finally, Chapter 6 takes a broader perspective on different integrative strategies in negotiations (i.e., expanding the pie, logrolling, solving underlying interests), thereby laying the groundwork for future research.