Refine
Year of publication
Document Type
- Article (15)
- Bachelor Thesis (15)
- Master's Thesis (14)
- Diploma Thesis (7)
- Book (4)
- Part of a Book (3)
- Report (3)
Institute
- Physikalische Technik, Informatik (61) (remove)
Language
- English (61) (remove)
Abstract:
Background: Proctoring represents a cornerstone in the acquisition of state‐of‐the‐art cardiovascular interventions. Yet, travel restrictions and containment measures during the COVID‐19 pandemic limited on‐site proctoring for training and expert support in interventional cardiology.
Methods and Results: We established a teleproctoring setup for training in a novel patent foramen ovale closure device system (NobleStitch EL, HeartStitch Inc, Fountain Valley, CA) at our institution using web‐based real‐time bidirectional audiovisual communication. A total of 6 patients with prior paradoxical embolic stroke and a right‐to‐left shunt of grade 2 or 3 were treated under remote proctorship after 3 cases were performed successfully under on‐site proctorship. No major device/procedure‐related adverse events occurred, and none of the patients had a residual right‐to‐left shunt of grade 1 or higher after the procedure. Additionally, we sought to provide an overview of current evidence available for teleproctoring in interventional cardiology. Literature review was performed identifying 6 previous reports on teleproctoring for cardiovascular interventions, most of which were related to the current COVID‐19 pandemic. In all reports, teleproctoring was carried out in similar settings with comparable setups; no major adverse events were reported.
Conclusions: Teleproctoring may represent a feasible and safe tool for location‐independent and cost‐effective training in a novel patent foramen ovale closure device system. Future prospective trials comparing teleproctoring with traditional on‐site proctoring are warranted.
Context
VR as an application to enhance well-being is sparsely researched in the elderly population. The aim of the pilot study was to analyze the effect of 360° videos of different categories on the state of mind of seniors in nursing facilities. Furthermore, for the implementation in everyday life, the usability of the system and the experience for seniors should be evaluated.
Methods
The VR experience was used as a supplement to existing care services in three facilities on eight subjects. Mood state was assessed using the Questionnaire for the Assessment of Happiness before and after the intervention. Demographic data and technology acceptance were collected beforehand. After the intervention, subjects were interviewed about confounding factors and side effects, and nursing home staff were interviewed about the usability of the system and the organizational concept of implementation.
Results
There was a positive effect on state of mind. Gender and spatial mobility turned out to be influencing factors. Categories containing people, animals and action achieved the highest increases in the state of mind. Interest in using technical devices correlated negatively with the change in mood state. None of the subjects found the VR goggles distracting or reported motion sickness. Very good usability was indicated by the employees.
Conclusion
A very high willingness to use this technology was found among nursing staff and residents. The tendencies of the positive effect of 360° videos on the state of mind, as well as differentiation based on the mentioned characteristics gender and spatial mobility, should be verified by a larger sample to empirically validate the use of this technology to increase the quality of life.
Electrical and thermal measurements were conducted during the plasma electrolytic polishing (PEP) of cemented tungsten carbide (WC-Co) materials to characterize energetic aspects of the process in relation to the temporal development of the gaseous layer near the workpiece. The power transferred to the workpiece is determined using a calorimetric probe and employing the time derivative of the temperature curve. It shows distinct heating phases due to the generation of the gaseous layer. At the beginning of the process, a typical power of 367 ± 17 W is transferred to the workpiece of a surface area of 14 cm2. At longer process times, a stabilized gaseous layer limits the power transferred to the workpiece to 183 ± 3 W. In an attempt to describe the heat transferred to the electrolyte, the electrolyte temperature was measured using a thermocouple situated 15 mm away from the workpiece. The local electrolyte temperature increases from 70 to 81 °C for an immersion depth of 20 mm. Moreover, the spatiotemporal development of the electrolyte temperature was obtained by 2D-hydrodynamic modeling using COMSOL Multiphysics®. The modeling results for the local temporal temperature development are in excellent agreement with the experimental values when the turbulent model is applied up to t = 65 s. Afterward, the laminar model leads to a better agreement. Furthermore, line scan x-ray photoelectron spectroscopy revealed that aliphatic carbon was preferentially removed. Only a slight compositional gradient in the vertical direction after the PEP process was observed.
Routing games over time are widely studied due to various applications, e.g., transportation, road and air traffic control, logistic in production systems, communication networks like the internet, and financial flows. In this article, we present a new competitive packet routing game with edge priorities motivated by traffic and transportation. In this model a set of selfishly acting players travels through the network over time. If the number of players who want to enter an edge at the same time exceeds the inflow capacity of this edge, then edge priorities with respect to the preceding edge are used to resolve these conflicts, which is similar to right-of-way rules in traffic. We analyze the efficiency of pure Nash equilibria, present an efficient algorithm for computing equilibria in symmetric games, and show that it is NP-hard to decide whether a Nash equilibrium exists in an asymmetric game. Furthermore, we address the problem of constructing optimal priorities.
Certifying Fully Dynamic Algorithms for Recognition and Hamiltonicity of Threshold and Chain Graphs
(2023)
Solving problems on graphs dynamically calls for algorithms to function under repeated modifications to the graph and to be more efficient than solving the problem for the whole graph from scratch after each modification. Dynamic algorithms have been considered for several graph properties, for example connectivity, shortest paths and graph recognition. In this paper we present fully dynamic algorithms for the recognition of threshold graphs and chain graphs, which are optimal in the sense that the costs per modification are linear in the number of modified edges. Furthermore, our algorithms also consider the addition and deletion of sets of vertices as well as edges. In the negative case, i.e., where the graph is not a threshold graph or chain graph anymore, our algorithms return a certificate of constant size. Additionally, we present optimal fully dynamic algorithms for the Hamiltonian cycle problem and the Hamiltonian path problem on threshold and chain graphs which return a vertex cutset as certificate for the non-existence of such a path or cycle in the negative case.
Abstract
This article presents a cost-effective ultraviolet-ozone cleaner (UV/O3 Cleaner) for surface pre-treatment of substrates in the field of semiconductor technology. The cleaner consists of two chambers, the upper one contains the electronics, including the time counter. The lower chamber contains the two UV sterilisation lamps and a UV reflector of anodized aluminium, which confines the area of high Ozone concentration in the area of interest. The device is successfully used for surface cleaning and modification of different materials. To this end, the two important wavelengths 253.7 nm (excitation of organic residues) and 184.9 nm (production of ozone from the atmospheric environment as a strong oxidant) were first detected. The effectiveness of UV/O3 cleaning is demonstrated by improving the properties of indium tin oxide (ITO) for OLED fabrication. The contact angle of water to ITO could be reduced from 90° to 3° and for diiodomethane, it was reduced from 55° to 31° within the 10 min of irradiation. This greatly improved wettability for polar and non-polar liquids can increase the flexibility in further process control. In addition, an improvement in wettability is characterized by measuring the contact angles for titanium dioxide (TiO2) and polydimethylsiloxane (PDMS). The contact angle of water to TiO2 decreased from 70° to 10°, and that of diiodomethane to TiO2 from 54° to 31°. The wettability of PDMS was also greatly increased. Here, the contact angle of water was reduced from 109° to 24° and the contact angle to diiodomethane from 89° to 49°.
Article Highlights
We report a cost-effective dry-cleaning device for surface cleaning and modification based on ultraviolet-ozone irradiation.
Contact angle measurements show an increase of wettability for different materials due to surface modification.
The UVO3 pre-treatment improves layer formation and optoelectrical properties of OLEDs.
Sodium iron hexacyanoferrate (NaFeHCF) films were electrodeposited on Au/Cr/Si for the study of growth behavior and physical properties. The NaFeHCF films were studied by different analytical methods to prove the chemical composition, morphology and crystal structure. The grains of the film grow with a cubic structure with an average lattice parameter of 10.10 Å and the preferential growth direction along the [111] direction of the cubic cell. The films show a repeatable bipolar resistive switching behavior accompanied by high current changes (up to a factor of ~105). The different resistive states in the materials are dominated by ohmic conduction.
The electrical conduction mechanism of resistive switching Prussian white (PW) thin films obtained by the electrodeposition method was examined by AC impedance spectroscopy and DC current–voltage measurements. Using an electrode tip to contact PW grown over Au, robust unipolar resistive switching was observed with a current change of up to three orders of magnitude, high repeatability, and reproducibility. Moreover, electrical impedance spectroscopy showed that the resistive switching comes from small conductive filaments formed by potassium ions before the establishment of larger conductive channels. Both voltammetry and EIS measurements suggest that the electrical properties and conductive filament formation are influenced by defects and ions present in the grain boundaries. Thus, PW is a potential material for the next generation of ReRAM devices.