Fak. 4 Elektrotechnik und Informatik

1293 Items

Recent Submissions
Thermische Untersuchung von Schaltungsträgern für leistungselektronische Halbleitermodule mit organischem Isolator

Bicakci, Aylin (2019)

Aufgrund der stetig steigenden Leistungsdichte in der Leistungselektronik sind immer höhere Temperaturen der Halbleiter in Leistungsmodulen die Folge, welche zu einer Leistungsbeschränkung der heutigen Module führen. Konventionelle Module bestehen häufig aus einem Direct Copper Bonded-Substrat (DCB), welches auf eine Bodenplatte (Wärmespreizer) gelötet ist. Diese Module sind aus thermischer Sic...

Towards exact molecular dynamics simulations with invariant machine-learned models

Chmiela, Stefan (2019)

Molecular dynamics (MD) simulations constitute the cornerstone of contemporary atomistic modeling in chemistry, biology, and materials science. However, one of the widely recognized and increasingly pressing issues in MD simulations is the lack of accuracy of underlying classical interatomic potentials, which hinders truly predictive modeling of dynamics and function of (bio)molecular systems. ...

Untersuchungen an weich schaltenden DC/DC Konvertern zur Versorgung von Hochleistungs-Diodenlasern

Winkler, Tammo (2019)

Durch die Steigerung der Dynamik von Laser-Materialbearbeitungsprozessen mittels Diodenlasern wächst der Bedarf an hochdynamischen Stromquellen, mit denen die Emitter betrieben werden können. Dabei nehmen mannigfaltige Randbedingungen Einfluss auf den grundlegenden Systemaufbau der stromgeregelten leistungselektronischen Systeme. Es wird das industrielle Einsatzgebiet der Stromquellen beschrie...

A Response to the United Nations CITES Blockchain Challenge: Incremental and Integrative PoA-based Permit Exchange

Busse, Anselm ; Eberhardt, Jacob ; Frost, Sebastian ; Kim, Dong-Ha ; Weilbier, Thore ; Renner, Lukas ; Roth, Matthias ; Tai, Stefan (2019-07-01)

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) negotiated and administered by the United Nations Environment Programme (UNEP) regulates the international trade of endangered species and derived products through a permit-based system. Currently, the permit process is paper-based and hence highly prone to manipulations and errors. Being aware of blockc...

Towards adaptive multi-robot systems: self-organization and self-adaptation

Hrabia, Christopher-Eyk ; Lützenberger, Marco ; Albayrak, Sahin (2018-10-04)

The development of complex systems ensembles that operate in uncertain environments is a major challenge. The reason for this is that system designers are not able to fully specify the system during specification and development and before it is being deployed. Natural swarm systems enjoy similar characteristics, yet, being self-adaptive and being able to self-organize, these systems show benef...

Explainable software systems

Vogelsang, Andreas (2019-07-02)

Software and software-controlled technical systems play an increasing role in our daily lives. In cyber-physical systems, which connect the physical and the digital world, software does not only influence how we perceive and interact with our environment but software also makes decisions that influence our behavior. Therefore, the ability of software systems to explain their behavior and decisi...

Inhomogeneities in Battery Packs

Neupert, Steven ; Kowal, Julia (2018-06-28)

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Derandomizing Compressed Sensing With Combinatorial Design

Jung, Peter ; Kueng, Richard ; Mixon, Dustin G. (2019-06-06)

Compressed sensing is the art of effectively reconstructing structured n-dimensional vectors from substantially fewer measurements than naively anticipated. A plethora of analytical reconstruction guarantees support this credo. The strongest among them are based on deep results from large-dimensional probability theory and require a considerable amount of randomness in the measurement design. H...

Simultaneous Structures in Convex Signal Recovery—Revisiting the Convex Combination of Norms

Kliesch, Martin ; Szarek, Stanislaw J. ; Jung, Peter (2019-05-28)

In compressed sensing one uses known structures of otherwise unknown signals to recover them from as few linear observations as possible. The structure comes in form of some compressibility including different notions of sparsity and low rankness. In many cases convex relaxations allow to efficiently solve the inverse problems using standard convex solvers at almost-optimal sampling rates. A st...

Materialaspekte der Hydridgasphasenepitaxie von Aluminiumgalliumnitrid

Fleischmann, Simon (2019)

In dieser Arbeit wurden Aspekte zur Verbesserung der Materialqualität von AlGaN-Schichten untersucht, die mittels HVPE abgeschieden wurden. Diese umfassten einerseits die Strukturierung von Saphirsubstraten und die Prozessschritte Pufferschicht und Kompositionsvariationen sowie andererseits die Wahl des Reaktormaterials zu Vermeidung von parasitären Reaktionen und Fremdatomeinbau. Zunächst wur...

Predictable GPUs Frequency Scaling for Energy and Performance

Fan, Kaijie ; Cosenza, Biagio ; Juurlink, Ben (2019)

Dynamic voltage and frequency scaling (DVFS) is an important solution to balance performance and energy consumption, and hardware vendors provide management libraries that allow the programmer to change both memory and core frequencies. The possibility to manually set these frequencies is a great opportunity for application tuning, which can focus on the best applicationdependent setting. Howev...

Efficient Bayesian Inference of Sigmoidal Gaussian Cox Processes

Donner, Christian ; Opper, Manfred (2018)

We present an approximate Bayesian inference approach for estimating the intensity of a inhomogeneous Poisson process, where the intensity function is modelled using a Gaussian process (GP) prior via a sigmoid link function. Augmenting the model using a latent marked Poisson process and Polya--Gamma random variables we obtain a representation of the likelihood which is conjugate to the GP prior...

Quantifizierung der räumlichen Lichtverteilung

Liedtke, Carolin (2019)

Diese Dissertation stellt ein neues Modell zur Quantifizierung der räumlichen Lichtverteilung vor. Aufgrund fehlender Eignung von etablierten Beschreibungsgrößen in der aktuellen Lichtplanungspraxis entsteht ein neues Beschreibungsmodell, um die Lichtverteilung im Raum hinsichtlich der Lichteinfallsrichtung und ihrer Diffusität besser zu beschreiben. Zur Überprüfung dieses neuen Modells werden ...

Investigation of perovskite-CIGSe tandem solar cells

Wang, Yajie (2019)

Multi-junction photovoltaic devices have received much attention for a long time due to their potential performance beyond the Shockley-Queisser (S-Q) limit compared with the current (commercially available) single junction solar cells. Thin film solar cells based on polycrystalline Cu(In,Ga)(S,Se)2 (CIGSe) absorbers and hybrid organic-inorganic perovskite solar cells have reached power convers...

CIE Test Cases — Bewertung der Genauigkeit von softwarebasierter Lichtberechnung

Liedtke, Carolin (2014-02-05)

Validation of the light simulation software Dialux and Relux shows an overall good accuracy according to the CIE Test Cases (Technical Report 171:2006). However, data reveal also limitations of the test procedure, provided reference data, and validity of tested aspects.

Advanced EEG signal processing with applications in brain-computer interfaces

Nicolae, Irina-Emilia (2019)

Advances in signal processing push forward the Neurotechnology domain along with the Brain-Computer Interface (BCI) research which deals with the analysis of brain activity. Heading for a future that will most probably happen, where either healthy persons or people with disabilities communicate and control external devices without muscle control, a symbiotic relationship between humans and mach...

Bayesian inference of inhomogeneous point process models

Donner, Christian (2019)

Arrival times of airplanes, positions of car accidents or astronomical objects in space, locations of ecological crisis, spike times of neurons, etc. are all data that surround us and can be viewed as realisations of point processes. Nowadays, the modelling of these data becomes increasingly more important, when we attempt to draw meaningful conclusions from this ever expanding amount of data. ...

Modelling and integrating personality as affective phenomenon in agent-based systems

Ahrndt, Sebastian (2019)

A team member's ability to predict the actions of other team members influences the efficiency of teamwork. This is named predictability and one of the challenges associated with the task of making agents team player in joint human-agent activities. I approach this problem focusing on personality as a predictor of human behaviour and following a combination of theory and data-driven approaches...

Requirements Quality Is Quality in Use

Femmer, Henning ; Vogelsang, Andreas (2019)

The quality of requirements engineering artifacts is widely considered a success factor for software projects. Currently, the definition of high-quality or good RE artifacts is often provided through normative references, such as quality standards, textbooks, or generic guidelines. We see various problems of such normative references: (1) It is hard to ensure that the contained rules are comple...

Compiling Modelica

Höger, Christoph (2019)

The equation-based object-oriented modeling language Modelica is an openly accessible standard with many implementations and applications. Most, if not all, tools that execute a Modelica simulation follow a common scheme: Models are loaded, composed, analyzed, and transformed into a system of equations. This system is then further simplified, translated into efficient code, and simulated....