Chaos and Order in Event-Triggered Control

Event-triggered control (ETC) is claimed to provide significant reductions in sampling frequency when compared to periodic sampling, but little is formally known about its generated traffic. This work shows that ETC can exhibit very complex, even chaotic traffic, especially when the triggering condition is aggressive in reducing...

Computational methods for leakage localisation in a vacuum bag using volumetric flow rate measurements: Delft University of Technology, German Aerospace Center

The localisation of leakages during the vacuum bagging process of a composite is currently time intensive and reliant on human labour. The purpose of this article is to explore four computational methods for leakage localisation using volumetric flow rate (VFR) data to increase the automation of the process. The data used in this article is...

Model predictive control with memory-based discrete search for switched linear systems

Controlling systems with both continuous and discrete actuators using model predictive control is often impractical, since mixed-integer optimization problems are too complex to solve sufficiently fast. This paper proposes a parallelizable method to control both the continuous input and the discrete switching signal for linear switched...

The chemical consequences of the gradual decrease of the ionic radius along the Ln-series

In the periodical system, the lanthanides (the 15 elements in the periodic table between barium and hafnium) are unique in the sense that their trivalent cations have their valence electrons hidden behind the 5s and 5p electrons. They show a gradual decrease in ionic radius with increasing atomic number (also known as the lanthanide...

Temperature-dependent phonon spectra of magnetic random solid solutions

A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed. The method takes fluctuations of force constants due to magnetic excitations as well as due to chemical disorder into account. The developed approach correctly predicts the experimentally...

Phonon broadening in high entropy alloys

Refractory high entropy alloys feature outstanding properties making them a promising materials class for next-generation high-temperature applications. At high temperatures, materials properties are strongly affected by lattice vibrations (phonons). Phonons critically influence thermal stability, thermodynamic and elastic properties, as well as...

Accurate Electromagnetic Modeling Methods for Integrated Circuits

The present development of modern integrated circuits (IC’s) is characterized by a number of critical factors that make their design and verification considerably more difficult than before. This dissertation addresses the important questions of modeling all electromagnetic behavior of features on the chip, efficient methods to solve large...

Chaotic behavior in an algorithm to escape from poor local minima in lens design

In lens design, damped least-squares methods are typically used to find the nearest local minimum to a starting configuration in the merit function landscape. In this paper, we explore the use of such a method for a purpose that goes beyond local optimization. The merit function barrier, which separates an unsatisfactory solution from a...

Multi-Scale Modeling of Gas Flows with Continuum-Rarefied Transitions Application to Expanding Gas Jets in Thin Film Deposition Processes

Instabilities and fractal basins of attraction in optical system optimization

Many optical design programs use various forms of the damped least-squares method for local optimization. In this paper, we show that damped least-squares algorithms, with maximized computational speed, can create sensitivity with respect to changes in initial conditions. In such cases, starting points, which are very close to each other, lead...

Modeling and Inversion of Scattered Surface waves

In this thesis, we present a modeling method based on a domain-type integral representation for waves propagating along the surface of the Earth which have been scattered in the vicinity of the source or the receivers. Using this model as starting point, we formulate an inversion scheme to estimate properties of scattering objects close to the...

Fully developed laminar flow in curved ducts

A mathematical model of steady, fully developed laminar flow in curved ducts is developed and used to derive a simplified computation method to be applied in another mathematical model predicting the flow in river bends. The laminar flow model is verified by comparing its results with analytical, numerical and experimental results reported in...