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Dispersion-curve inversion of Rayleigh waves to infer subsurface shear-wave velocity is a long-standing problem in seismology. Due to nonlinearity and ill-posedness, sophisticated regularization techniques are required to solve the problem for a stable velocity model. We have formulated the problem as a minimization problem with nonlinear operator constraint and then solve it by using an inexact augmented Lagrangian method, taking advantage of the Haney-Tsai Dix-type relation (a global linear approximation of the nonlinear forward operator). This replaces the original regularized nonlinear problem with iterative minimization of a more tractable regularized linear problem followed by a nonlinear update of the phase velocity (data) in which the update can be performed accurately with any forward modeling engine, for example, the finite-element method. The algorithm allows discretizing the medium with thin layers (for the finite-element method) and thus omitting the layer thicknesses from the unknowns and also allows incorporating arbitrary regularizations to shape the desired velocity model. In this research, we use total variation regularization to retrieve the shear-wave velocity model. We use two synthetic and two real data examples to illustrate the performance of the inversion algorithm with total variation regularization. We find that the method is fast and stable, and it converges to the solution of the original nonlinear problem.
Ausgehend von der Debatte um die Genderaspekte der Digitalisierung der Arbeit untersuchen wir den Zusammenhang zwischen der Nutzung digitaler Technologien und der Entwicklung von Geschlechterungleichheiten empirisch. Die Ergebnisse zeigen, dass Frauen in Branchen mit hohem Digitalisierungsgrad unterrepräsentiert sind und dass sich diese Dimension der Geschlechtersegregation in den letzten Jahren verstärkte. Die Unterrepräsentation von Frauen in Branchen mit hohem Digitalisierungsgrad geht mit Nachteilen bei den Verdiensten einher. Die Ergebnisse zeigen zudem, dass der Gender Pay Gap in Branchen mit hohem Digitalisierungsgrad tendenziell größer ist und über die Zeit weniger zurückging als in Branchen, in denen weniger digitale Technologien genutzt werden.
The following article deals with the new-institutionalist concept of buffering. The concept describes in short, how organizations cope with external and internal demands in order to gain or maintain legitimacy. The article applies this approach to quality management in higher education. We argue, that the introduction of quality management is a reaction to external demands to achieve more quality in teaching and learning. Simultaneously, it functions as a buffer for other organizational subunits within the higher education institution and tries to prevent them from becoming overloaded with external demands. Based on interviews from a research project, the article shows, that both quality managers and higher education managers partly perceive quality management as service unit, which prevents the departments from exaggerating external demands.
Eine evidenzbasierte Gestaltung von Studium und Lehre, wie sie heute normativ eingefordert wird, bedarf des integrierten Zusammenwirkens von Qualitätsmanagement und Hochschuldidaktik – aber gibt es dieses in der Praxis? Mit Blick auf die allgemeine Befundlage, aber auch anhand einer eigenen empirischen Untersuchung zeigt der Beitrag diesbezüglich auf, dass Qualitätsmanagement und Hochschuldidaktik als weitgehend desintegrierte Funktionsbereiche wahrgenommen werden und Evidenzbasierung in der Praxis folglich keinen sehr hohen Stellenwert genießt. Ausgehend von einer Ursachenanalyse wird auf die dysfunktionalen, aber auch auf die funktionalen Auswirkungen dieser Separierung aufmerksam gemacht.
The combined effect of ultraviolet (UV) light soaking and self-assembled monolayer deposition on the work function (WF) of thin ZnO layers and on the efficiency of hole injection into the prototypical conjugated polymer poly(3-hexylthiophen-2,5-diyl) (P3HT) is systematically investigated. It is shown that the WF and injection efficiency depend strongly on the history of UV light exposure. Proper treatment of the ZnO layer enables ohmic hole injection into P3HT, demonstrating ZnO as a potential anode material for organic optoelectronic devices. The results also suggest that valid conclusions on the energy-level alignment at the ZnO/organic interfaces may only be drawn if the illumination history is precisely known and controlled. This is inherently problematic when comparing electronic data from ultraviolet photoelectron spectroscopy (UPS) measurements carried out under different or ill-defined illumination conditions.
The termprocess modelis widely used, but rarely agreed upon. This paper proposes a framework for characterizing and building cognitive process models. Process models model not only inputs and outputs but also model the ongoing information transformations at a given level of abstraction. We argue that the following dimensions characterize process models: They have a scope that includes different levels of abstraction. They specify a hypothesized mental information transformation. They make predictions not only for the behavior of interest but also for processes. The models' predictions for the processes can be derived from the input, without reverse inference from the output data. Moreover, the presumed information transformation steps are not contradicting current knowledge of human cognitive capacities. Lastly, process models require a conceptual scope specifying levels of abstraction for the information entering the mind, the proposed mental events, and the behavior of interest. This framework can be used for refining models before testing them or after testing them empirically, and it does not rely on specific modeling paradigms. It can be a guideline for developing cognitive process models. Moreover, the framework can advance currently unresolved debates about which models belong to the category of process models.