A Whitehead theorem for periodic homotopy groups

We show that $v_n$-periodic homotopy groups detect homotopy equivalences between simply-connected finite CW-complexes

Magnetoresistive and Thermoresistive Scanning Probe Microscopy with Applications in Micro- and Nanotechnology

This work presents approaches to extend limits of scanning probe microscopy techniques towards more versatile instruments using integrated sensor concepts. For structural surface analysis, magnetoresistive sensing is introduced and thermoresistive sensing is applied to study nanoscale phonon transport in chain-like molecules. Investigating with these techniques the properties of shape memory polymers, a fabrication method to design application-inspired micro- and nanostructures is introduced

A smartphone-based health care chatbot to promote self-management of chronic pain (SELMA) : pilot randomized controlled trial

Background: Ongoing pain is one of the most common diseases and has major physical, psychological, social, and economic impacts. A mobile health intervention utilizing a fully automated text-based health care chatbot (TBHC) may offer an innovative way not only to deliver coping strategies and psychoeducation for pain management but also to build a working alliance between a participant and the TBHC. Objective: The objectives of this study are twofold: (1) to describe the design and implementation to promote the chatbot painSELfMAnagement (SELMA), a 2-month smartphone-based cognitive behavior therapy (CBT) TBHC intervention for pain self-management in patients with ongoing or cyclic pain, and (2) to present findings from a pilot randomized controlled trial, in which effectiveness, influence of intention to change behavior, pain duration, working alliance, acceptance, and adherence were evaluated. Methods: Participants were recruited online and in collaboration with pain experts, and were randomized to interact with SELMA for 8 weeks either every day or every other day concerning CBT-based pain management (n=59), or weekly concerning content not related to pain management (n=43). Pain-related impairment (primary outcome), general well-being, pain intensity, and the bond scale of working alliance were measured at baseline and postintervention. Intention to change behavior and pain duration were measured at baseline only, and acceptance postintervention was assessed via self-reporting instruments. Adherence was assessed via usage data. Results: From May 2018 to August 2018, 311 adults downloaded the SELMA app, 102 of whom consented to participate and met the inclusion criteria. The average age of the women (88/102, 86.4%) and men (14/102, 13.6%) participating was 43.7 (SD 12.7) years. Baseline group comparison did not differ with respect to any demographic or clinical variable. The intervention group reported no significant change in pain-related impairment (P=.68) compared to the control group postintervention. The intention to change behavior was positively related to pain-related impairment (P=.01) and pain intensity (P=.01). Working alliance with the TBHC SELMA was comparable to that obtained in guided internet therapies with human coaches. Participants enjoyed using the app, perceiving it as useful and easy to use. Participants of the intervention group replied with an average answer ratio of 0.71 (SD 0.20) to 200 (SD 58.45) conversations initiated by SELMA. Participants’ comments revealed an appreciation of the empathic and responsible interaction with the TBHC SELMA. A main criticism was that there was no option to enter free text for the patients’ own comments. Conclusions: SELMA is feasible, as revealed mainly by positive feedback and valuable suggestions for future revisions. For example, the participants’ intention to change behavior or a more homogenous sample (eg, with a specific type of chronic pain) should be considered in further tailoring of SELMA

Interior dynamics of tidally locked super-Earths

Within the last few years, a large number of rocky exoplanets with masses larger than Earth have been detected. These so-called super-Earths do not exist in our Solar System and their tectonic regimes could be substantially different than Earth’s. Current and near-future astronomical observations are capable of measuring the masses, radii and sometimes even the surface temperature of these planets with unprecedented precision, and we can now use these measurements to probe their interior dynamics. To achieve this, we run geodynamic simulations of the interior mantle flow using the mantle convection code StagYY in the two-dimensional spherical annulus geometry. We constrain the longitudinal surface temperature dependence using the results from thermal phase curve observations and general circulation models. Many super-Earths are on very short orbits and are therefore most likely tidally locked. This means that the same hemisphere always faces the host star, which can lead to a strong temperature contrast between the dayside and nightside. In Chapter 1, I present our results on the interior dynamics of super-Earth LHS 3844b. The thermal phase curve of this planet suggests that this planet lacks a substantial atmosphere. The dayside temperature is around 1040K and the nightside temperature is consistent with zero K. Our numerical simulations suggest that this planet could exhibit hemispheric tectonics if it has a strong lithosphere. In such a regime, a cold and viscous downwelling is located predominantly on one hemisphere and hot upwellings are getting flushed around the core-mantle-boundary (CMB) towards the other hemisphere, where they rise towards the surface. Such a regime is currently absent in our Solar System and this work is the first observationally constrained indication that such a regime could operate on exoplanets. In Chapter 2, we investigate the case of super-Earth GJ 486b that is very similar to LHS 3844b in terms of size. For this planet, it is not (yet) known whether it was able to retain its atmosphere. However, it is a suitable target for future follow-up observations that aim to characterise its atmosphere and we therefore investigate in this study what tectonic regimes could operate on this planet for different surface temperature contrasts that are derived from different types of atmospheres. This study provided also an opportunity to investigate further what causes hemispheric tectonics and if it could operate on planets with smaller temperature contrasts between dayside and nightside. As with LHS 3844b, we find that hemispheric tectonics is favoured for planets with strong lithospheres. However, a strong temperature contrast between dayside and nightside and overall higher (dayside) surface temperatures are needed in order for the downwelling to be pinned to one hemisphere. In Chapter 3, we study the case of lava world 55 Cancri e. This is the first rocky exoplanet for which a thermal phase has been observed. This planet’s dayside temperature is around 2700K and the nightside is roughly 1380K. Therefore, the dayside most likely harbours a magma ocean which could potentially even extend towards the nightside. In this study, we investigate the impact of such a global magma ocean on the interior mantle dynamics. We parametrise heat transport inside the magma ocean through a very high eddy diffusivity. We find that if both hemispheres are molten, the magma ocean will tend to equilibrate the temperatures at the interface between the magma ocean and the underlying solid mantle and dichotomous mantle convection is therefore less likely. If only the dayside is molten, we find that a massive plume forms on the dayside of the planet which rises from the CMB towards the magma ocean. In conclusion, we find that rocky super-Earths that are on very short orbits around their host star could exhibit tectonic regimes that are unlike anything we currently observe in our Solar System. A planet’s tectonic regime is inherently related to its atmosphere through long-term cycling of volatiles through outgassing. Our work has therefore important consequences for current and upcoming space missions, such as CHEOPS, JWST, ARIEL or PLATO that will target super-Earths and aim to characterise their atmospheres and surface composition. A spatially-variable release of volatiles might for example lead to secondary features in thermal phase curve observations

Proposing A Supply Chain Analytics Reference Model As Performance Enabler

Nowadays firms have to react quickly to changing markets creating a need for accurate forecasts of demand and supply. In a data-rich environment as it is within the field of supply chain management, much information needs to be stored, processed, and transformed for decision making. To deal with the increasing amounts of data, firms must be aware of chances in supply chain management such as supply chain analytic capabilities to stay agile, flexible, and make use of (complex) data. Supply chain analytics can predict patterns and trends, even in high velocity markets in real-time supporting decision making by using supply chain analytic tools based on data. The benefits of successfully implementing supply chain analytic processes are enormous and result in competitive advantages for companies such as lowering costs while increasing revenues. As many companies fail to apply supply chain analytic processes and tools, this paper examines the challenges, benefits, and factors for the introduction of supply chain analytics using the input-output model

Probing Atomic Structure and Majorana Wavefunctions in Mono-Atomic Fe-chains on Superconducting Pb-Surface

Motivated by the striking promise of quantum computation, Majorana bound states (MBSs) in solid-state systems have attracted wide attention in recent years. In particular, the wavefunction localization of MBSs is a key feature and crucial for their future implementation as qubits. Here, we investigate the spatial and electronic characteristics of topological superconducting chains of iron atoms on the surface of Pb(110) by combining scanning tunneling microscopy (STM) and atomic force microscopy (AFM). We demonstrate that the Fe chains are mono-atomic, structured in a linear fashion, and exhibit zero-bias conductance peaks at their ends which we interprete as signature for a Majorana bound state. Spatially resolved conductance maps of the atomic chains reveal that the MBSs are well localized at the chain ends (below 25 nm), with two localization lengths as predicted by theory. Our observation lends strong support to use MBSs in Fe chains as qubits for quantum computing devices.Comment: 13 pages, 3 figure

Situationsbasiertes Scheduling von Echtzeit-Tasks in verteilten eingebetteten Systemen

Die Anforderungen an die verfügbare Rechenkapazität von Steuergeräten in der Automotive und Avionik-Domäne steigen kontinuierlich an. Dieser Anstieg ist auf die steigende Bedeutung von softwarebasierten Funktionen zurückzuführen, sowie auf die damit einhergehende steigende Anzahl und Komplexität der softwarebasierten Funktionen. In dieser Dissertation wird die Berücksichtigung der Situation (z. B. die geographische Position oder die Geschwindigkeit) als ein möglicher Ansatz beschrieben, um den steigenden Bedarf an Rechenkapazität der softwarebasierten Funktionen zu decken. Die benötigte Rechenkapazität einer softwarebasierten Funktion verändert sich in Abhängigkeit von der momentanen Situation. Durch die Berücksichtigung der Situation bei der Verteilung der Rechenkapazitäten entstehen freie Rechenkapazitäten, welche durch komplementäre softwarebasierte Funktion verwendet werden können. Die Zielsetzung dieser Dissertation ist es, eine situationsbasierte Verteilung der Rechenkapazität auf die softwarebasierten Funktionen des verteilen eingebetteten Systems zu erreichen.:1 Einleitung 1.1 Motivation 1.2 Zielsetzung 1.3 Struktur der Arbeit 1.4 Zusammenfassung 2 Grundlagen 2.1 Situationsbasierte Systeme 2.2 Eingebettete verteilte Systeme 2.2.1 Architektur 2.2.2 Echtzeit-Tasks 2.2.3 Echtzeit-Scheduling 2.2.4 Echtzeit-Kommunikation 2.2.5 Steuergeräte der Zieldomänen 2.3 Prozessmigration in verteilten Systemen 2.3.1 Prozesssegmente 2.3.2 Möglichkeiten der Prozessmigration 2.4 Application checkpointing 2.5 Zusammenfassung 3 Stand der Forschung 3.1 Situationsbasiertes Scheduling für eingebettete verteilte Systeme 3.1.1 Semi-Statische Systeme 3.1.2 Dynamische Systeme 3.2 Situationsbasiertes Scheduling für Multi-Core Systeme 3.2.1 Situationen in HAMS 3.2.2 HAMS Architektur 3.2.3 Wissensdatenbank 3.3 Semi-Statische Netzwerkkonfiguration 3.4 Zusammenfassung 4 Situationsbasiertes Scheduling in verteilten eingebetteten Systemen 4.1 Analyse der Zielsetzung 4.2 Technische Ziele 4.3 SiVES-Sched Konzept 4.3.1 Erweiterter HAMS 4.3.2 Situations-Wissensdatenbank 4.3.3 TLS Master 4.3.4 Task-Migration 4.3.5 TLS Slave 4.3.6 Software Defined Network 4.3.7 TLS-KM 4.4 Zusammenfassung 5 Evaluation 5.1 Konzept der Evaluation 5.2 Evaluationsumgebung 5.2.1 Hardwareumgebung 5.2.2 Softwareumgebung 5.3 Rekonfiguration des verteilten eingebetteten Systems 5.3.1 Evaluation I: Erstellung der SWDB 5.3.2 Evaluation II: Durchführung der Rekonfiguration 5.3.3 Evaluation III: Dauer des kritischen Abschnitts 5.3.4 Evaluation IV: Vermeidung von Informationsverlust 5.4 Zusammenfassung 6 Zusammenfassung und Ausblick 6.1 Ergebnisse dieser Arbeit 6.1.1 Konzept 6.1.2 Evaluation 6.2 Ausblick 7 Appendix Literaturverzeichnis Nomenklatur Thesen Eigene Veröffentlichunge

Controlling structural, chemical and electronic properties of single molecules on surfaces

With the prospects of realizing electronic circuitry and machinery consisting of a single-molecule, the control of the molecular characteristics down to the atomic level is essential. In this thesis, fundamental investigations of structures, electronic properties and diffusion of molecules on surfaces are presented. The experiments are performed by means of scanning tunneling microscopy (STM) and atomic force microscopy (AFM) at low temperature in ultra-high vacuum. The control of elaborated structures is achieved by studying on-surface chemical reactions and spray-deposited molecules by high-resolution AFM imaging with CO terminated tips. To mimic a p-n junction, a donor-acceptor (DA) molecule on a thin insulating film is probed to disentangle its structure, electronic states and charge redistribution. Interestingly, the DA character of the molecule is altered at specific atomic positions, and thus controlled by inducing a change of the adsorption site by tip manipulation. This consists of an example of a molecular switch. In this line, tip manipulation experiments are pushed forward during the NanoCar Race by steering a single molecule over the surface using tunneling electrons. The results of this thesis demonstrate the impact of the molecular design on electronic and adhesion properties influencing the performance of such molecular systems