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Data fusions are becoming increasingly relevant in official statistics. The aim of a data fusion is to combine two or more data sources using statistical methods in order to be able to analyse different characteristics that were not jointly observed in one data source. Record linkage of official data sources using unique identifiers is often not possible due to methodological and legal restrictions. Appropriate data fusion methods are therefore of central importance in order to use the diverse data sources of official statistics more effectively and to be able to jointly analyse different characteristics. However, the literature lacks comprehensive evaluations of which fusion approaches provide promising results for which data constellations. Therefore, the central aim of this thesis is to evaluate a concrete plethora of possible fusion algorithms, which includes classical imputation approaches as well as statistical and machine learning methods, in selected data constellations.
To specify and identify these data contexts, data and imputation-related scenario types of a data fusion are introduced: Explicit scenarios, implicit scenarios and imputation scenarios. From these three scenario types, fusion scenarios that are particularly relevant for official statistics are selected as the basis for the simulations and evaluations. The explicit scenarios are the fulfilment or violation of the Conditional Independence Assumption (CIA) and varying sample sizes of the data to be matched. Both aspects are likely to have a direct, that is, explicit, effect on the performance of different fusion methods. The summed sample size of the data sources to be fused and the scale level of the variable to be imputed are considered as implicit scenarios. Both aspects suggest or exclude the applicability of certain fusion methods due to the nature of the data. The univariate or simultaneous, multivariate imputation solution and the imputation of artificially generated or previously observed values in the case of metric characteristics serve as imputation scenarios.
With regard to the concrete plethora of possible fusion algorithms, three classical imputation approaches are considered: Distance Hot Deck (DHD), the Regression Model (RM) and Predictive Mean Matching (PMM). With Decision Trees (DT) and Random Forest (RF), two prominent tree-based methods from the field of statistical learning are discussed in the context of data fusion. However, such prediction methods aim to predict individual values as accurately as possible, which can clash with the primary objective of data fusion, namely the reproduction of joint distributions. In addition, DT and RF only comprise univariate imputation solutions and, in the case of metric variables, artificially generated values are imputed instead of real observed values. Therefore, Predictive Value Matching (PVM) is introduced as a new, statistical learning-based nearest neighbour method, which could overcome the distributional disadvantages of DT and RF, offers a univariate and multivariate imputation solution and, in addition, imputes real and previously observed values for metric characteristics. All prediction methods can form the basis of the new PVM approach. In this thesis, PVM based on Decision Trees (PVM-DT) and Random Forest (PVM-RF) is considered.
The underlying fusion methods are investigated in comprehensive simulations and evaluations. The evaluation of the various data fusion techniques focusses on the selected fusion scenarios. The basis for this is formed by two concrete and current use cases of data fusion in official statistics, the fusion of EU-SILC and the Household Budget Survey on the one hand and of the Tax Statistics and the Microcensus on the other. Both use cases show significant differences with regard to different fusion scenarios and thus serve the purpose of covering a variety of data constellations. Simulation designs are developed from both use cases, whereby the explicit scenarios in particular are incorporated into the simulations.
The results show that PVM-RF in particular is a promising and universal fusion approach under compliance with the CIA. This is because PVM-RF provides satisfactory results for both categorical and metric variables to be imputed and also offers a univariate and multivariate imputation solution, regardless of the scale level. PMM also represents an adequate fusion method, but only in relation to metric characteristics. The results also imply that the application of statistical learning methods is both an opportunity and a risk. In the case of CIA violation, potential correlation-related exaggeration effects of DT and RF, and in some cases also of RM, can be useful. In contrast, the other methods induce poor results if the CIA is violated. However, if the CIA is fulfilled, there is a risk that the prediction methods RM, DT and RF will overestimate correlations. The size ratios of the studies to be fused in turn have a rather minor influence on the performance of fusion methods. This is an important indication that the larger dataset does not necessarily have to serve as a donor study, as was previously the case.
The results of the simulations and evaluations provide concrete implications as to which data fusion methods should be used and considered under the selected data and imputation constellations. Science in general and official statistics in particular benefit from these implications. This is because they provide important indications for future data fusion projects in order to assess which specific data fusion method could provide adequate results along the data constellations analysed in this thesis. Furthermore, with PVM this thesis offers a promising methodological innovation for future data fusions and for imputation problems in general.
Anmerkung: Es handelt sich um die 2. überarbeitete Auflage der Dissertation.
1. Auflage siehe:
"https://ubt.opus.hbz-nrw.de/frontdoor/index/index/docId/2083".
Ausgangspunkt der politisch-ikonographischen Untersuchung, in deren
Zentrum zwei Staatsporträts König Maximilians II. von Bayern stehen, ist die Beobachtung, dass diese beiden Bildnisse grundsätzlich unterschiedliche Inszenierungsformen wählen. Das erste von Max Hailer gefertigte Werk zeigt Maximilian II. im vollen bayerischen Krönungsornat und greift eine tradierte Darstellungsweise im Staatsporträt auf. Es entstand zwei Jahre nach Maximilians II. Thronbesteigung und damit nach den revolutionären Unruhen der Jahre 1848/49 im Jahr 1850. Das zweite wurde von Joseph Bernhardt 1857 bis 1858 gemalt und im Jahr 1858 zum zehnjährigen Thronjubiläum des Monarchen erstmals präsentiert. Die Inszenierung ändert sich im zweiten Bildnis: Das bayerische Krönungsornat ist der Generalsuniform gewichen, ebenso weitere Details, die sich noch in der ersten Darstellung finden: Draperie und Wappen fehlen, der übliche bayerisch-königliche Thronsessel ist durch einen anderen ersetzt. In den Hintergrund gedrängt ist die Verfassung, immerhin seit 1818 staatliche Rechtsgrundlage des bayerischen Königreichs. Die beiden Staatsporträts Maximilians II. leiten offensichtlich von den Herrscherbildnissen im vollen bayerischen Krönungsornat seines Großvaters Maximilian I. und Vaters Ludwig I. über zu einer solchen in Uniform mit Krönungsmantel wie sie sich bei Napoleon III. und Friedrich Wilhelm IV. finden und wie sie sein Sohn Ludwig II. weiterführte. Es stellt sich somit die Frage, welche Faktoren zu diesem prägnanten Wandel in der Inszenierung Maximilians II. als König von Bayern führten. Die Arbeit geht der These nach, dass beide Darstellungen grundlegend auf eine reaktionäre, gegen die Revolution 1848/49 gerichtete Politik ausgelegt sind, wobei dieser reaktionäre Charakter in Maximilians II. Bildnis von 1858 noch eine Steigerung im Vergleich zu derjenigen von 1850 erfährt. Zudem wandelt sich die innenpolitisch-historische Ausrichtung des ersten Porträts bei der zweiten Darstellung des bayerischen Monarchen in eine außenpolitisch-progressive. Die Legitimation Maximilians II. begründet sich nicht mehr, wie bei ersterem, in der Geschichte und der Herrschaft der Wittelsbacher, sondern in seinen eigenen Errungenschaften und seiner eigenen Herrschaft. Dieser Wechsel der politischen Bildaussage fußt sowohl auf den politischen Veränderungen und Entwicklungen innerhalb und außerhalb Bayerns als auch auf der Entwicklung des Staatsporträts in der Mitte des 19. Jahrhunderts. Nach nur zehn Jahren wird so eine veränderte Botschaft über Maximilians II. Position und Machtanspruch ausgesendet.
Left ventricular assist devices (LVADs) have become a valuable treatment for patients with advanced heart failure. Women appear to be disadvantaged in the usage of LVADs and concerning clinical outcomes such as death and adverse events after LVAD implant. Contrary to typical clinical characteristics (e.g., disease severity), device-related factors such as the intended device strategy, bridge to a heart transplantation or destination therapy, are often not considered in research on gender differences. In addition, the relevance of pre-implant psychosocial risk factors, such as substance abuse and limited social support, for LVAD outcomes is currently unclear. Thus, the aim of this dissertation is to explore the role of pre-implant psychosocial risk factors for gender differences in clinical outcomes, accounting for clinical and device-related risk factors.
In the first article, gender differences in pre-implant characteristics of patients registered in The European Registry for Patients with Mechanical Circulatory Support (EUROMACS) were investigated. It was found that women and men differed in multiple pre-implant characteristics depending on device strategy. In the second article, gender differences in major clinical outcomes (i.e., death, heart transplant, device explant due to cardiac recovery, device replacement due to complications) were evaluated for patients in the device strategy destination therapy in the Interagency Registry for Mechanically Assisted Circulation (INTERMACS). Additionally, the association of gender and psychosocial risk factors with the major outcomes were analyzed. Women had similar probabilities to die on LVAD support, and even higher probabilities to experience explant of the device due to cardiac recovery compared with men in the destination therapy subgroup. Pre-implant psychosocial risk factors were not associated with major outcomes. The third article focused on gender differences in 10 adverse events (e.g., device malfunction, bleeding) after LVAD implant in INTERMACS. The association of a psychosocial risk indicator with gender and adverse events after LVAD implantation was evaluated. Women were less likely to have psychosocial risk pre-implant but more likely to experience seven out of 10 adverse events compared with men. Pre-implant psychosocial risk was associated with adverse events, even suggesting a dose response-relationship. These associations appeared to be more pronounced in women.
In conclusion, women appear to have similar survival to men when accounting for device strategy. They have higher probabilities of recovery, but higher probabilities of device replacement and adverse events compared with men. Regarding these adverse events, women may be more susceptible to psychosocial risk factors than men. The results of this dissertation illustrate the importance of gender-sensitive research and suggest considering device strategy when studying gender differences in LVAD recipients. Further research is warranted to elucidate the role of specific psychosocial risk factors that lead to higher probabilities of adverse events, to intervene early and improve patient care in both, women and men
Knowledge acquisition comprises various processes. Each of those has its dedicated research domain. Two examples are the relations between knowledge types and the influences of person-related variables. Furthermore, the transfer of knowledge is another crucial domain in educational research. I investigated these three processes through secondary analyses in this dissertation. Secondary analyses comply with the broadness of each field and yield the possibility of more general interpretations. The dissertation includes three meta-analyses: The first meta-analysis reports findings on the predictive relations between conceptual and procedural knowledge in mathematics in a cross-lagged panel model. The second meta-analysis focuses on the mediating effects of motivational constructs on the relationship between prior knowledge and knowledge after learning. The third meta-analysis deals with the effect of instructional methods in transfer interventions on knowledge transfer in school students. These three studies provide insights into the determinants and processes of knowledge acquisition and transfer. Knowledge types are interrelated; motivation mediates the relation between prior and later knowledge, and interventions influence knowledge transfer. The results are discussed by examining six key insights that build upon the three studies. Additionally, practical implications, as well as methodological and content-related ideas for further research, are provided.
Semantic-Aware Coordinated Multiple Views for the Interactive Analysis of Neural Activity Data
(2024)
Visualizing brain simulation data is in many aspects a challenging task. For one, data used in brain simulations and the resulting datasets is heterogeneous and insight is derived by relating all different kinds of it. Second, the analysis process is rapidly changing while creating hypotheses about the results. Third, the scale of data entities in these heterogeneous datasets is manifold, reaching from single neurons to brain areas interconnecting millions. Fourth, the heterogeneous data consists of a variety of modalities, e.g.: from time series data to connectivity data, from single parameters to a set of parameters spanning parameter spaces with multiple possible and biological meaningful solutions; from geometrical data to hierarchies and textual descriptions, all on mostly different scales. Fifth, visualizing includes finding suitable representations and providing real-time interaction while supporting varying analysis workflows. To this end, this thesis presents a scalable and flexible software architecture for visualizing, integrating and interacting with brain simulations data. The scalability and flexibility is achieved by interconnected services forming in a series of Coordinated Multiple View (CMV) systems. Multiple use cases are presented, introducing views leveraging this architecture, extending its ecosystem and resulting in a Problem Solving Environment (PSE) from which custom-tailored CMV systems can be build. The construction of such CMV system is assisted by semantic reasoning hence the term semantic-aware CMVs.
Der zentrale Gegenstand der Untersuchung ist die Rechtsfigur des Indigenats im Kontext der württembergischen und preußischen Staatenlandschaft. Das Indigenat lässt sich als ein Recht bestimmen, das seine potenziellen Rechtsträger maßgeblich über das Abstammungsprinzip definiert und ein Verhältnis zwischen Rechtsträger und einem übergeordneten Rechtssubjekt zum Ausdruck bringt, sei es lehns- oder standes-, staats- oder auch bundes- beziehungsweise reichsrechtlicher Natur. Der zeitliche Schwerpunkt der Betrachtung liegt auf dem 19. Jahrhundert. Es werden jedoch auch Rückblicke in die Frühe Neuzeit geworfen, weil Wandel und Kontinuität in der Entwicklung des Indigenats in einer solch langen Perspektive besonders klar hervortreten können. Die zentrale These dieser Arbeit ist, dass ein enger Zusammenhang zwischen der im 19. Jahrhundert entstehenden und bis heute geläufigen Form der Zuordnung von Menschen zum Staat und den aus diesem Verhältnis entspringenden Rechten einerseits und dem frühneuzeitlichen Indigenat andererseits besteht. Dabei kann gezeigt werden, dass Gesellschaften ihre politischen Machtpositionen gegenüber „fremdstämmigen“, etwa zuwandernden Personen abschirmten, indem sie sich auf indigenatrechtliche, ethnische Bestimmungen beriefen.