Fakultäten & Zentralinstitute

6796 Items

Recent Submissions
Urban foraging in Berlin: people, plants and practices within the metropolitan green infrastructure

Landor-Yamagata, Jonah L. ; Kowarik, Ingo ; Fischer, Leonie Katharina (2018-06-04)

Gathering wild plants in cities (urban foraging) is likely an important, but understudied human-nature interaction globally. As large European cities are critically understudied in this regard, we performed in-depth ethnography-based interviews in Berlin, Germany, to shed light on the cultural background of foragers, their motivations and which plants and fungi are gathered for which purposes. ...

Construction of an improved Aspergillus niger platform for enhanced glucoamylase secretion

Fiedler, Markus R. M. ; Barthel, Lars ; Kubisch, Christin ; Nai, Corrado ; Meyer, Vera (2018-06-16)

Background The lifestyle of filamentous fungi depends on the secretion of hydrolytic enzymes into the surrounding medium, which degrade polymeric substances into monomers that are then taken up to sustain metabolism. This feature has been exploited in biotechnology to establish platform strains with high secretory capacity including Aspergillus niger. The accepted paradigm is that proteins bec...

Back- and front-side texturing for light-management in perovskite / silicon-heterojunction tandem solar cells

Jošt, Matej ; Albrecht, Steve ; Lipovšek, Benjamin ; Krč, Janez ; Korte, Lars ; Rech, Bernd ; Topič, Marko (2016-12)

The perovskite / silicon-heterojunction (SHJ) tandem solar cell can theoretically overcome the efficiencies of the single junction solar cells with experimental results not far behind. Here, we use optical simulations to analyze the potential of such currently feasible monolithic perovskite / SHJ tandem devices. We consider three different device designs in the optical simulations: planar devic...

The role of contextual factors for breastfeeding outcomes and their potential integration inted guidelines: case studies of Germany, the United Kingdom and Ghana

Waldherr, Ruth (2018)

Introduction: Breastfeeding is recognized as an important public health issue with high social and economic implications. According to the WHO, it should be initiated within one hour after birth, exclusive breastfeeding should be practiced for six months, and the entire period should last for two years. However, breastfeeding rates are sub-optimal at a worldwide scale and could be improved. Rec...

The PSS quality framework for solar home systems

Kebir, Noara Zohra ; Philipp, Daniel (2016-08)

In September 2015, the United Nations General Assembly has adopted the Sustainable Development Goals; they include SDG 7 targeting universal access to electricity by 2030. Reaching this goal implies huge investments in generation capacity, grid extension and densification. However, according to the International Energy Agency, 70% of the world's population currently excluded from electricity se...

Time-dependent recommender systems for the prediction of appropriate learning objects

Krauß, Christopher (2018)

This dissertation deals with adaptive learning technologies which aim to optimize Technology Enhanced Learning (TEL) offerings to fit the individual learner’s needs. Thereby, Recommender Systems play a key role in supporting the user’s decision process for items of interest. This works very well for e-commerce and Video on Demand services. However, it is found to be the case that these trad...

Tidal deformation of planets and satellites

Steinbrügge, Gregor (2018)

In this thesis, methods are developed and studied for radar and laser altimetry to measure radial tidal deformations of planets and satellites. The thesis investigates further how the tidal measurement allows constraining the interior structure and rheologic properties of the bodies. A semi-analytical performance model for laser altimetry has been developed to predict probability of false detec...

Magnetische und elektronische Eigenschaften von Übergangsmetallkomplexen in der Gasphase

Bülow, Christine (2018)

In dieser Arbeit wurde der Übergang von einem Hochspin- zu einem Niedrigspinzustand in verschiedenen Systemen mit jeweils einem Übergangsmetallatom mittels Röntgenabsorptions- und XMCD-Spektroskopie in der Gasphase untersucht. Im Vordergrund steht die Frage wie dieser magnetische Übergang von der Anzahl der 3d Elektronen, der Struktur und den Liganden abhängt. Dabei wird von in einem früheren P...

Microbial signatures and quality assessment of Siberian permafrost organic matter for future biogenic greenhouse gas production

Stapel, Janina Gabriele (2018)

The Earth´s high latitude regions, where recent warming has been amplified, are of particular concern in the light of future climate change. Annual average temperatures in the Arctic have risen by 0.6 °C per decade over the last 30 years, and this warming trend resulted into the thaw of perennially frozen ground (permafrost), which exposes substantial amounts of previously frozen organic carbon...

SLRefactor: Ein Refactoring-Ansatz für Simulink-Modelle

Tran, Quang Minh ; Winkler, Jonas Paul ; Dziobek, Christian (2015)

Bei der Funktionsmodellierung ist die Veränderung und Erweiterung der Struktur eines Modells eine häufig durchgeführte Aktivität. Während es bereits Refactoring-Ansätze für textuelle Programmiersprachen wie Java, C# usw. gibt, fehlt ein vergleichbarer, integraler und durchgehender Ansatz für Simulink-Modelle. Wir haben einen automatisierten Refactoring-Ansatz (im Folgenden SLRefactor-Ansatz gen...

Design, control and analysis of a novel multilevel converter with a reduced switch count

Norambuena, Margarita (2018)

Multilevel converters are used in a wide range of applications, such as drives, energy conversion and distributed generation. This Thesis proposes a new multilevel converter topology that allows increasing the number of output voltage levels with a fewer required power semiconductors than in standard multilevel topologies such as Active Neutral Point Clamped (ANPC), Flying Capacitor Converter (...

Automatic glossary term extraction from large-scale requirements specifications

Gemkow, Tim ; Conzelmann, Miro ; Hartig, Kerstin ; Vogelsang, Andreas (2018)

Creating glossaries for large corpora of requirments is an important but expensive task. Glossary term extraction methods often focus on achieving a high recall rate and, therefore, favor linguistic proecssing for extracting glossary term candidates and neglect the benefits from reducing the number of candidates by statistical filter methods. However, especially for large datasets a reduction o...

Microscopic aspects of ageing in Al-Mg-Si alloys

Madanat, Mazen (2018)

Al-Mg-Si alloys with a low solute content (0.4 %Mg, 0.4 %Si) and higher contents (Mg+Si=1.4 %, all in wt.%) were solutionized, quenched and then either artificially aged (AA) at 180 °C or naturally pre-aged (NPA) for 2 weeks at room temperature and then reverse aged (RA) at 250 °C. Subsequently, positron annihilation lifetime spectroscopy was applied with the objective of obtaining information ...

Behagliche Monumentalität in Frankfurt

Enders, Tina (2018)

Bisherige architektursoziologische Ansätze, die den Zusammenhang von Gesellschaft und Architektur aufzuschlüsseln versuchen, beziehen sich in aller Regel nur sehr wenig bis gar nicht auf das direkte bauliche Umfeld und dessen physisch-materiellen Aspekte. Auch der Entstehungsprozess von Architekturen gerät nur selten in den Untersuchungsfokus. Zwar werden regelmäßig soziale Vorgänge in eine dir...

Multidimensional modulation formats for optical transmission systems

Alreesh, Saleem (2018)

The ever-increasing demand for bandwidth is constantly driving deployment of new strategies to enable the upgrading of current optical transmission systems. Therefore, next generation optical networks are required to be elastic and more efficiently utilize the available optical spectrum; this in turn increases spectral efficiency and overall network capacity. To this end, future optical transce...

Verwendung von Krankenhausabrechnungsdaten für die Versorgungsforschung in Deutschland

Nimptsch, Ulrike (2018)

Seitdem die akutstationären Krankenhausleistungen in Deutschland auf der Grundlage des fallpauschalierenden Vergütungssystems der Diagnosis Related Groups (DRG) vergütet werden, sind in den administrativen Datenbeständen der deutschen Krankenhäuser umfassende medizinische Informationen verfügbar. Da die Abrechnung nach dem DRG-System für nahezu alle Patienten und alle Krankenhäuser zur Anwendun...

Design of high performance indium phosphide (InP) - based quantum dot light emitting diodes (QLEDs)

Kim, Yohan (2018)

This dissertation is dedicated to the development and understanding of fundamental device mechanism and engineering of the device architecture of quantum dot light-emitting diodes (QLEDs) based on indium phosphide (InP) quantum dots. QLEDs have emerged as a next-generation flat panel display (FPD) technology with promising properties. Their device performance and fabrication methods are develop...

Property-performance correlations in the oxidative coupling of methane

Wang, Huan (2018)

The oxidative coupling of methane is a “dream reaction” in heterogeneous catalysis to achieve direct conversion for natural gas towards value-added and easily transportable C2 products with high economic relevance. Although extensive academic papers and patents have been reported over the last three decades, no economically viable industrial-scale application is yet achieved because of the limi...

Optimierung der normgerechten Intensitätsbewertung und Untersuchung weiterer Referenzgerüche zur Qualitätssicherung

Brosig, Laura (2018)

For energy saving purposes buildings are constructed increasingly airtight. Due to insufficient ventilation emissions from building materials and products might accumulate indoors. Not only emissions of volatile organic compounds (VOC) may cause impact on health and well-being of occupants but odours as well. Therefore, their perceived intensity can be assessed based on acetone as reference sub...

Die Natur als Vorbild und Partner

Steup, Lara (2018)

Der menschliche Umgang mit den natürlichen Ressourcen der Erde hat dramatische ökologische (und soziale) Folgen: Hierzu gehören der Klimawandel, der degradierte Zustand unserer Ökosysteme sowie der damit einhergehende hohe Verlust der Biodiversität. Trotz aller Bemühungen um eine nachhaltige Entwicklung konnte in diesen Bereichen bisher keine Trendwende erzielt werden. Der Wissenschaftliche Bei...