The 10 most recently published documents
Die Untersuchung verbindet Methoden der Korpuslinguistik und des close readings, um an einem repräsentativen Einzeltext mittlerer Länge das Verhältnis der syntaktischen und metrischen Ebene im mittelhochdeutschen Reimpaarvers zu untersuchen. Herausgearbeitet werden regelmäßig wiederkehrende Muster, die beide Ebenen stets gleich aufeinander abbilden. Diese Regelmäßigkeiten lassen sich aus den Lautstrukturen des mhd. Wortschatzes, den syntaktischen Bauplänen der Phrasen und Sätze, schließlich den Erfordernissen des metrischen Schemas erklären. Der häufig zur Erklärung herangezogene Reimzwang erweist sich bei näherer Betrachtung als eher sekundärer Einfluss auf die syntaktische Struktur. Neben typischen „Normalfällen“ bei denen sich statistisch häufige Betonungsmuster der Wörter, in üblichen, einfachen Satzstellungsmustern in immer gleicher Weise problemlos in den Reimpaarvers integrieren lassen, können auch wiederkehrende Abweichungsvarianten erklärt und beschrieben werden. Die festgestellten Regularitäten sind nur zu einem kleinen Teil und in wenigen Fällen deterministisch, es lässt sich jedoch, um die statistischen Auffälligkeiten zu begründen, zeigen, welche Vorteile sich aus bestimmten Varianten ergeben und welche Schwierigkeiten bei anderen entstehen, wie sich eine Variante durch eine andere ersetzen lässt. Beschrieben wird so der Gestaltungsraum des Dichters und die von ihm gewählten Lösungen. Indirekt ergibt sich zugleich ein Negativbild der Syntax, die den Zwängen des metrischen Schemas nicht unterworfen ist.
Ziel der hier bereitgestellten Anforderungskataloge ist es, einen Überblick über die Anforderungen zu geben, welche an FDM-Services in den Geisteswissenschaften und in der Psychologie gestellt werden. Dies soll Hochschulen und außeruniversitären Forschungseinrichtungen die Möglichkeit geben, ihre eigenen Servicekataloge um FDM-Services zu erweitern, welche auf die spezifischen Bedarfe der Forschenden in diesen Disziplinen abgestimmt sind. Zudem sollen diese Anforderungskataloge als Vorlage für die Entwicklung weiterer Anforderungskataloge dienen, welche die fachspezifischen FDM-Services in anderen Fachdisziplinen spezifizieren.
Das hier beschriebene Qualifizierungskonzept zur Unterstützung eines forschungsprozessbegleitenden Forschungsdatenmanagements (FDM) stellt einen zentralen Baustein im Rahmen des durch das BMBF geförderten Forschungsprojektes „Prozessorientierte Entwicklung von Managementinstrumenten für Forschungsdaten im Lebenszyklus“ (PODMAN) dar. Die Frage, die das PODMAN-Projekt mit dem hier vorgestellten Qualifizierungskonzept adressieren möchte, ist dabei nicht primär, welche Inhalte für den Erwerb der verschiedenen Kompetenzen von Bedeutung sind, sondern vielmehr auf welche Art und Weise diese Inhalte vermittelt werden sollten. Eine Fokussierung auf die Darlegung eines konkreten Designs für Qualifizierungsmaßnahmen im Bereich FDM anstelle von spezifischen Inhalten ist insofern sinnvoll, als dass letztere transient sind und somit ohnehin einer kontinuierlichen Anpassung bedürfen. Nichtsdestotrotz wird in diesem Qualifizierungskonzept auf hilfreiche FDM-Informationsplattformen verwiesen.
Forschungsprozessspezifische Kompetenzmatrix für die Einführung des Forschungsdatenmanagements (FDM)
(2018)
Die forschungsprozessspezifische Kompetenzmatrix stellt einen Baustein im Rahmen des durch das BMBF geförderten Forschungsprojektes „Prozessorientierte Entwicklung von Managementinstrumenten für Forschungsdaten im Lebenszyklus“ (PODMAN) dar. Im Rahmen des PODMAN-Projektes soll ein Referenzmodell und ein zugehöriges prozessorientiertes Benchmarking-Verfahren zur Implementierung des Forschungsdatenmanagements an Hochschulen und außeruniversitären Forschungseinrichtungen entwickelt werden. Darüber soll den Hochschulen und außeruniversitären Forschungseinrichtungen ein Orientierungsrahmen bereitgestellt werden, den sie flexibel zur Umsetzung eigener Datenmanagementstrategien nutzen können. In diesem Zusammenhang sollen Instrumente entwickelt werden, welche eine erfolgreiche Organisation der Zusammenarbeit und Kommunikation sowie der Qualifizierung aller am Forschungsdatenmanagementprozess beteiligten Akteure erlauben. Die forschungsprozessspezifische Kompetenzmatrix hat als eines dieser Instrumente zwei Funktionen: Erstens definiert sie die zur Implementierung eines umfassenden institutionellen FDM-Konzeptes notwendigen Aufgaben und zweitens die damit verbundenen Kompetenzen der ausführenden Akteure.
The economic growth theory analyses which factors affect economic growth
and tries to analyze how it can last. A popular neoclassical growth model
is the Ramsey-Cass-Koopmans model, which aims to determine how much
of its income a nation or an economy should save in order to maximize its
welfare.
In this thesis, we present and analyze an extended capital accumulation equation of a spatial version of the Ramsey model, balancing diffusive and agglomerative effects. We model the capital mobility in space via a nonlocal
diffusion operator which allows for jumps of the capital stock from one lo-
cation to an other. Moreover, this operator smooths out heterogeneities in
the factor distributions slower, which generated a more realistic behavior of
capital flows. In addition to that, we introduce an endogenous productivity-
production operator which depends on time and on the capital distribution
in space. This operator models the technological progress of the economy.
The resulting mathematical model is an optimal control problem under a
semilinear parabolic integro-differential equation with initial and volume constraints, which are a nonlocal analog to local boundary conditions, and box-constraints on the state and the control variables. In this thesis, we consider
this problem on a bounded and unbounded spatial domain, in both cases with
a finite time horizon. We derive existence results of weak solutions for the
capital accumulation equations in both settings and we proof the existence
of a Ramsey equilibrium in the unbounded case. Moreover, we solve the
optimal control problem numerically and discuss the results in the economic
context.
This dissertation is dedicated to the analysis of the stabilty of portfolio risk and the impact of European regulation introducing risk based classifications for investment funds.
The first paper examines the relationship between portfolio size and the stability of mutual fund risk measures, presenting evidence for economies of scale in risk management. In a unique sample of 338 fund portfolios we find that the volatility of risk numbers decreases for larger funds. This finding holds for dispersion as well as tail risk measures. Further analyses across asset classes provide evidence for the robustness of the effect for balanced and fixed income portfolios. However, a size effect did not emerge for equity funds, suggesting that equity fund managers simply scale their strategy up as they grow. Analyses conducted on the differences in risk stability between tail risk measures and volatilities reveal that smaller funds show higher discrepancies in that respect. In contrast to the majority of prior studies on the basis of ex-post time series risk numbers, this study contributes to the literature by using ex-ante risk numbers based on the actual assets and de facto portfolio data.
The second paper examines the influence of European legislation regarding risk classification of mutual funds. We conduct analyses on a set of worldwide equity indices and find that a strategy based on the long term volatility as it is imposed by the Synthetic Risk Reward Indicator (SRRI) would lead to substantial variations in exposures ranging from short phases of very high leverage to long periods of under investments that would be required to keep the risk classes. In some cases, funds will be forced to migrate to higher risk classes due to limited means to reduce volatilities after crises events. In other cases they might have to migrate to lower risk classes or increase their leverage to ridiculous amounts. Overall, we find if the SRRI creates a binding mechanism for fund managers, it will create substantial interference with the core investment strategy and may incur substantial deviations from it. Fruthermore due to the forced migrations the SRRI degenerates to a passive indicator.
The third paper examines the impact of this volatility based fund classification on portfolio performance. Using historical data on equity indices we find initially that a strategy based on long term portfolio volatility, as it is imposed by the Synthetic Risk Reward Indicator (SRRI), yields better Sharpe Ratios (SRs) and Buy and Hold Returns (BHRs) for the investment strategies matching the risk classes. Accounting for the Fama-French factors reveals no significant alphas for the vast majority of the strategies. In our simulation study where volatility was modelled through a GJR(1,1) - model we find no significant difference in mean returns, but significantly lower SRs for the volatility based strategies. These results were confirmed in robustness checks using alternative models and timeframes. Overall we present evidence which suggests that neither the higher leverage induced by the SRRI nor the potential protection in downside markets does pay off on a risk adjusted basis.
Kartenschätze aus Italien
(2018)
Die Entdeckungen der Neuzeit sowie verbesserte Druckverfahren führten ab dem 16. Jahrhundert zu einem enormen Aufschwung der Kartographie. Gerade in Italien entstanden blühende kartographische Zentren mit exzellentem Ruf, die innerhalb kurzer Zeit große Fortschritte hinsichtlich Genauigkeit und Übersichtlichkeit machten. Aus dem der Universitätsbibliothek Trier vermachten Nachlass des Kartensammlers Fritz Hellwig werden drei repräsentative Beispiele vorgestellt.
The implicit power motive is one of the most researched motives in motivational
psychology—at least in adults. Children have rarely been subject to investigation and there
are virtually no results on behavioral and affective correlates of the implicit power motive in
children. As behavior and affect are important components of conceptual validation, the
empirical data in this dissertation focused on identifying three correlates, namely resource
control behavior (study 1), power stress (study 2), and persuasive behavior (study 3). In each
study, the implicit power motive was measured via the Picture Story Exercise, using an
adapted version for children. Children across samples were between 4 and 11 years old.
Results from study 1 and 2 showed that children’s power-related behavior corresponded with
evidence from adult samples: children with a high implicit power motive secure attractive
resources and show negative reactions to a thwarted attempt to exert influence. Study 3
contradicted existing evidence with adults in that children’s persuasive behavior was not
associated with nonverbal, but with verbal strategies of persuasion. Despite this inconsistency,
these results are, together with the validation of a child-friendly Picture Story Exercise
version, an important step into further investigating and confirming the concept of the implicit
power motive and how to measure it in children.
A matrix A is called completely positive if there exists an entrywise nonnegative matrix B such that A = BB^T. These matrices can be used to obtain convex reformulations of for example nonconvex quadratic or combinatorial problems. One of the main problems with completely positive matrices is checking whether a given matrix is completely positive. This is known to be NP-hard in general. rnrnFor a given matrix completely positive matrix A, it is nontrivial to find a cp-factorization A=BB^T with nonnegative B since this factorization would provide a certificate for the matrix to be completely positive. But this factorization is not only important for the membership to the completely positive cone, it can also be used to recover the solution of the underlying quadratic or combinatorial problem.rnrnIn addition, it is not a priori known how many columns are necessary to generate a cp-factorization for the given matrix. The minimal possible number of columns is called the cp-rank of A and so far it is still an open question how to derive the cp-rank for a given matrix. Some facts on completely positive matrices and the cp-rank will be given in Chapter 2.rnrnMoreover, in Chapter 6, we will see a factorization algorithm, which, for a given completely positive matrix A and a suitable starting point, computes the nonnegative factorization A=BB^T. The algorithm therefore returns a certificate for the matrix to be completely positive. As introduced in Chapter 3, the fundamental idea of the factorization algorithm is to start from an initial square factorization which is not necessarily entrywise nonnegative, and extend this factorization to a matrix for which the number of columns is greater than or equal to the cp-rank of A. Then it is the goal to transform this generated factorization into a cp-factorization.rnrnThis problem can be formulated as a nonconvex feasibility problem, as shown in Section 4.1, and solved by a method which is based on alternating projections, as proven in Chapter 6.rnrnOn the topic of alternating projections, a survey will be given in Chapter 5. Here we will see how to apply this technique to several types of sets like subspaces, convex sets, manifolds and semialgebraic sets. Furthermore, we will see some known facts on the convergence rate for alternating projections between these types of sets. Considering more than two sets yields the so called cyclic projections approach. Here some known facts for subspaces and convex sets will be shown. Moreover, we will see a new convergence result on cyclic projections among a sequence of manifolds in Section 5.4.rnrnIn the context of cp-factorizations, a local convergence result for the introduced algorithm will be given. This result is based on the known convergence for alternating projections between semialgebraic sets.rnrnTo obtain cp-facrorizations with this first method, it is necessary to solve a second order cone problem in every projection step, which is very costly. Therefore, in Section 6.2, we will see an additional heuristic extension, which improves the numerical performance of the algorithm. Extensive numerical tests in Chapter 7 will show that the factorization method is very fast in most instances. In addition, we will see how to derive a certificate for the matrix to be an element of the interior of the completely positive cone.rnrnAs a further application, this method can be extended to find a symmetric nonnegative matrix factorization, where we consider an additional low-rank constraint. Here again, the method to derive factorizations for completely positive matrices can be used, albeit with some further adjustments, introduced in Section 8.1. Moreover, we will see that even for the general case of deriving a nonnegative matrix factorization for a given rectangular matrix A, the key aspects of the completely positive factorization approach can be used. To this end, it becomes necessary to extend the idea of finding a completely positive factorization such that it can be used for rectangular matrices. This yields an applicable algorithm for nonnegative matrix factorization in Section 8.2.rnNumerical results for this approach will suggest that the presented algorithms and techniques to obtain completely positive matrix factorizations can be extended to general nonnegative factorization problems.
Die Dissertation untersucht den Anteil der Armutsthematik an der Etablierung des Kinos in Deutschland. Der Untersuchungsschwerpunkt konzentriert sich auf die Jahre 1907 bis 1913, einer entscheidenden Zeitspanne für die Institutionalisierung des Kinos als Medium sui generis. Ziel der Untersuchung ist es, anhand von Filmanalysen wiederkehrende Muster medialer Praktiken der kinematographischen Artikulation der Sozialen Frage zu eruieren und ihre thematische Relevanz bzw. ihren Anteil für die Etablierung des Kinos in Deutschland zu bestimmen. Im Fokus stehen die Medienprodukte, ihre Motivgestaltung und Inszenierungspraktiken.
