Refine
Year of publication
- 2019 (75) (remove)
Document Type
- Conference Proceeding (41)
- Article (13)
- Part of a Book (11)
- Book (6)
- Doctoral Thesis (1)
- Other (1)
- Periodical (1)
- Part of Periodical (1)
Institute
- Forschungszentrum Mikrotechnik (23)
- Forschungszentrum Business Informatics (11)
- Soziales & Gesundheit (11)
- Wirtschaft (11)
- Forschungszentrum Energie (7)
- Forschungszentrum Human Centred Technologies (6)
- Didaktik (mit 31.03.2021 aufgelöst; Integration ins TELL Center) (5)
- Technik | Engineering & Technology (5)
- Department of Engineering (Ende 2021 aufgelöst; Integration in die übergeordnete OE Technik) (3)
- Forschungsgruppe Empirische Sozialwissenschaften (3)
Has Fulltext
- no (75) (remove)
Is part of the Bibliography
- yes (75)
Keywords
- Constrained Optimization (3)
- silicon nitride (3)
- AAL (2)
- Evolution Strategies (2)
- Reflexive Kommunikationsprozesse (2)
- Theoretical Analysis (2)
- conically constrained problem (2)
- integrated photonics (2)
- repair by projection (2)
- AWG design (1)
Ursprünglich wurde für das K-Projekt „LiTech“ eine mobile und intuitive Robotersteuerung – mit Touchbedienung und Augmented Reality – programmiert. Ziel war es, einen Industrieroboter spontan steuern zu können, mit besonderem Augenmerk auf Laienfreundlichkeit. Das System besteht aus einem Roboter und einem PC der als Bildschirm eine mit kapazitivem Touch ausgestattete und von einem Projektor bespielte Glasscheibe hat. Daten werden als String über eine serielle Schnittstelle übermittelt. Zur Erforschung der Nutzerfreundlichkeit werden Bälle auf einer Ebene hin- und herbewegt. Zur Cloud-Datenauswertung und Erstellung der Visualisierung wurden mittlerweile weitere Forschungszentren der FH Vorarlberg eingebunden. Im laufenden Wintersemester arbeitet ein Praktikant aus Südamerika an der Erweiterung auf den kompletten 3D-Raum mit möglicher Implementierung einer Gestensteuerung. Ziel des Beitrags ist es, den Versuchsaufbau und die Steuerung des Roboters zu beschreiben sowie geplante Weiterentwicklungen aufzuzeigen.
Production and tribological characterization of tailored laser-induced surface 3D microtextures
(2019)
Investigations on mechanical stability of laser machined optical fibre tips for medical application
(2019)
Light delivery is a challenging task, when it comes to medical applications. The light is guided through optical fibers from the light source towards the treatment region. In case of interstitial light application, the light has to be decoupled from the fibre and spread to the surrounding tissue. To reach larger tissue volumes, this can be either obtained by adding a scattering volume to the tip of the fibre, or by directly modifying the optical fibre itself in order to break the total reflection within the fibre core. Such modifications can be either on the fibre surface itself or internally in the fibre core. One approach to obtain the fibre structuring could be laser induced surface roughening using an ultrafast laser source. While using volume scattering as diffusor at the fibre tip is currently the gold standard for non-thermal applications (< 0.3W/cm), the decoupling of high power laser intensities for thermal treatment options is still challenging. Structuring the fibre core itself usually is related with a loss of mechanical stability. As fibre breakage and potential loss within the human body can have serious consequences, the mechanical stability is one of the quality criterion in diffuser manufacturing. Therefore, investigations about the mechanical stability of laser manufactured optical fibre diffusers are needed.
In order to evaluate the mechanical stability, a 4-point as well as a 2-point breaking test were developed. Different fibre diffusers, based on volume or surface scattering, were manufactured using fs-laser ablation techniques and its breaking strengths were investigated.
It could be shown that for surface fibre modifications, the mechanical stability reduces with increasing defect depth. The stability significantly drops when the laser ablation was performed in the thermal energy range. Volume scattering modified fibres only showed a slight reduction in stability compared to un-machined fibres.
In conclusion, internal fibre modification seems to be the most promising method to establish optical fibre diffusers, which are capable of several watts of emission power, while preserving its mechanical strength.
Interstitial photodynamic therapy (iPDT) treats malignant brain cancer cells by irradiation with low power laser light. The light is guided into the human body by diffuse emitting fibers. This study targets the light distribution of optical diffusers within the brain tissue. It was shown, that by submerging an optical diffuser into human brain phantom, its radiation profile measured in air converges towards a Gaussian distribution with increasing phantom depth. A camera method using digital averaging filters as well as an integrating sphere setup, both, smoothing the diffuser radiation profile were applied onto the evaluated diffuser.
A multi-recombinative active matrix adaptation evolution strategy for constrained optimization
(2019)
Analysis of the (μ/μI,λ)-CSA-ES with repair by projection applied to a conically constrained problem
(2019)
Compact and high-resolution 256-channel silicon nitride based AWG-spectrometer for OCT on a chip
(2019)
We present design, simulation and technological verification of a compact 256-channel, 42-GHz silicon nitride based AWG-spectrometer. The spectrometer was designed for TM-polarized light with a central wavelength of 850 nm, applying “AWG-Parameters” tool. This design is based on a previous study of various AWG designs (8-channel, 100-GHz; 20-channel, 50-GHz; 40-channel, 50-GHz, 80-channel, 50-GHz and 160-channel, 50-GHz AWGs), which were all technologically verified. The spectrometer features small size and high resolution. It is integrated on OCT chip using standard CMOS processes. The SD-OCT system is developed to operate in a wavelength range from 800 nm to 900 nm, having 0.1 nm resolution.
Comparison of silicon nitride based 8-channel 100-GHz AWGs applying different waveguide structures
(2019)
This paper presents design and simulation of 8-channel, 100-GHz AWGs based on Si/SiO2/SiN/SiOx material platform. For the designs, two different waveguide structures were used, i.e. ridge and rib waveguides. AWGs were designed for central wavelength of 850 nm applying AWG-Parameters tool. The simulations were performed applying FEM and BPM methods in RSoft and PHASAR photonic tools. The simulation results show considerably lower losses but slightly higher channel crosstalk when applying rib waveguides.
Comparison of silicon nitride based 1x8 Y-branch splitters applying different waveguide structures
(2019)
This paper presents design, simulation and optimization of 1x8 Y-branch power splitters based on Si/SiO2/SiN/SiOx material platform. For the designs, two different waveguide structures were used, i.e. ridge and rib waveguides. The splitters were designed for 850 nm spectral optical window and the simulations were performed applying FEM and BPM methods in RSoft photonic tool. The aim of this work was to find minimum physical dimensions of the designed splitters occupying minimal space on PIC chip. The optimization was done with regards to high symmetrical splitting ratio and low insertion loss. Finally, the optical properties of both splitters were studied and compared with each other.
Optical splitters are passive optical components, which have found applications in a wide range of telecom, sensing, medical and many other scientific areas.
Low-index contrast optical splitters (Silica-on-Silicon (SoS) based waveguide devices) feature many advantages such as low fiber coupling losses and low propagation losses. They are considered an attractive DWDM solution in the telecommunication for all optical signal processing in optical communication systems. Nowadays the steadily increasing data volume in communication networks is driven by a rapid proliferation of home-based and business computers, storage capacities, processing capabilities and the extensive availability of Internet. The challenge is to transfer high data volumes in short periods of time over high distances as lossless as possible. The task of the optical splitters in Fiber-to-the-x (FTTx) network is to split one optical signal in many identical signals bringing for example the same TV signal in different households. Of course, the more buildings can be served by one optical splitter the lower are the installation costs.
High-index contrast optical splitters (such as silicon, silicon nitride or polymer based waveguide devices) feature much smaller waveguide size compared to low index contrast splitters. Such compact devices can easily be implemented on-chip and have already been used in the development of optical sensors, devices for DNA diagnostics and for infrared spectroscopy.
We will present the latest achievements in the design of two mostly used optical splitters (MMI and Y-branch) and discuss their advantages and disadvantages. Finally, some applications of the splitters developed in the frame of various projects will be presented.
This work was carried out in the framework of the project PHOCOP (no. SK-AT-2017-0013) and NAMOPRISIN (no. SK-AT-2017-0005) from the Slovak research and development agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic and SK 16/2018 and 15/2018 from OeAD-GmbH.
Abstract: ams AG is a leading provider of sensing solutions developing semiconductor sensors in a wide variety of fields, with optical sensing as one of the key competences. Since integrated photonics is a promising technology for new sensor systems, ams AG has been developing processes for fully integrated CMOS-compatible photonic components based on Si3N4. This talk will provide an overview on the processing of basic photonic building blocks and their optical properties and performance. We will also give examples for applications in the fields of optical coherence tomography and opto-chemical gas sensing. In the 1980s photonics started its way for common use in telecommunication technology, using optical fiber technologies. In recent years, also a variety of photonic sensors has been proposed and developed. One of the major drawbacks of most of these photonic devices has been the lack of integration into existing (semiconductor) production processes, so far. This integration is feasible using SiN material systems to process monolithically integrated CMOS-compatible photonic sensors in the visible and near-infrared spectrum. We will present the basic processing steps for the SiN photonic technology, the development of some critical processing steps such as SiN deposition and SiN etching as well as several photonic components (waveguides, splitters, etc.) with their optical properties. One of the applications presented relates to optical coherence tomography (OCT), a fast growing imaging technique in ophthalmology. Drawbacks of existing OCT systems are their high costs as well as their bulkiness, which prevents a wider spread use of OCT systems.
One way to overcome both cost and size issues is to integrate optical and electrical components on a single chip.
Part of this work was carried out in the framework of the projects COHESION (funded by the Austrian Research Promotion Agency (FFG), no. 848588), OCTCHIP (funded by the EU’ Horizon 2020 research and innovation programme, no. 688173), and COLODOR (M-ERA.NET transnational Call 2015, funded by the Austrian Research Promotion Agency (FFG), no.854066, and the Bundesministerium für Bildung und Forschung, Germany).
In this study, we carried out the structural and thermal characterization of a medical-grade poly (lactide) (PLA) by SEC, TGA, DSC, NMR, ICP-MS and Py-GC/MS. Moreover, we investigated the laser-induced degradation occurring when ultrashort laser pulses (ULP) were employed to cut extremely thin polymer films prepared by solvent-casting. ULP polymer cutting technology is an interesting manufacturing process for its advantages in potential medical applications. In fact, heat transmission to the region surrounding the cuts is limited, so that the incisions are precise and the effects on the regions around them are small. In this way, the need for post-processing is reduced and ULP cutting becomes interesting for industrial applications. However, degradation induced by ULP may occur and compromise the properties of the polymer samples. To investigate this possibility, portions of PLA films, ultrashort laser cut (ULC) and uncut, were analysed by SEC, DSC, NMR and FTIR. Furthermore, PLA oligomers were studied by ESI-MS. Both SEC and NMR showed a decrease in the molecular weight. FTIR, ESI-MS and NMR spectra revealed the presence of olefin end groups originated from a \beta-H transfer mechanism, induced by heat and/or light (Norrish II mechanism). Additionally, the inspection of the ESI mass spectra highlighted the cleavage of ester bonds related to the Norrish I type mechanism, undetected by the other techniques.
In contrast to fossil energy sources, the supply by renewable energy sources likewind and photovoltaics can not be controlled. Therefore, flexibilities on the demandside of the electric power grid, like electro-chemical energy storage systems, are usedincreasingly to match electric supply and demand at all times. To control those flex-ibilities, we consider two algorithms that both lead to linear programming problems.These are solved autonomously on the demand side, i.e., by household computers.In the classic approach, an energy price signal is sent by the electric utility to thehouseholds, which, in turn, optimize the cost of consumption within their constraints.Instead of an energy price signal, we claim that an appropriate power signal that istracked in L1-norm as close as possible by the household has favorable character-istics. We argue that an interior point of the household’s feasibility region is neveran optimal price-based point but can result in a L1-norm optimal point. Thus, pricesignals can not parametrize the complete feasibility region which may not lead to anoptimal allocation of consumption.We compare the price and power tracking algorithms over a year on the base ofone-day optimizations regarding different information settings and using a large dataset of daily household load profiles. The computational task constitutes an embarrassingly parallel problem. To this end, the performance of the two parallel computation frameworks DEF [1] and Ray [2] are investigated. The Ray framework is used to run the Python applications locally on several cores. With the DEF frameworkwe execute our Python routines parallelly in a cloud. All in all, the results providean understanding of when which computation framework and autonomous algorithmwill outperform the other.
We report resent results on the fabrication and characterization of carbon nanogap interdigitated electrode arrays (IDAs) for biosensor applications based on redox cycling. The electrochemical results of the carbon electrodes are compared to our fabricated gold electrodes with similar nanogap distances. The amplification factor and the collection efficiency were recorded by chronoamperometry. Cyclic voltammetry (CV) was utilized to determine the oxidation and reduction potentials as well as for monitoring the electron transfer process. The different deposited carbon materials were characterized by Raman spectroscopy.At present, we successfully fabricated carbon nanogaps down to 80 nm and we are convinced to reach the present fabrication limit of about 30 nm (for gold and platinum electrodes) with carbon as electrode material as well. To the best of our knowledge, this is the first IDA nanogap sensor, which features a gap distance under 100 nm with amorphous carbon as electrode material. Moreover, we present a signal amplification of 32 for carbon electrodes by redox cycling, which is the highest reported amplification so far.
Here we present the highly sensitive detection of dopamine using gold nanogap IDAs with redox-cycling amplification. Through the combination with a facile electrochemical activation and a chronoamperometric multistep protocol fouling of the gold electrode surface can be prevented and a sensitivity of 14 nA μM -1 with excellent linearity up to 10 μM is achieved. The low-cost and reproducible wafer level fabrication process of the nanogap IDAs plays a key role. Electrode and substrate materials can be nearly arbitrarily chosen. Also the gap sizes could be adjusted down to sub-100 nm dimensions with this versatile approach, allowing for very high signal amplification. In comparison to the current gold standard, fastscan cyclic voltammetry (FSCV) with carbon fiber microelectrodes (CFMEs), which suffers from high background currents, no elaborate data processing and high-end electronic equipment is needed. Employing our flexible, easy and inexpensive method, DA monitoring with a short acquisition period and a detection limit less than 200 nM is successfully demonstrated.
The electricity demand due to the increasing number of EVs presents new challenges for the operation of the electricity network, especially for the distribution grids. The existing grid infrastructure may not be sufficient to meet the new demands imposed by the integration of EVs. Thus, EV charging may possibly lead to reliability and stability issues, especially during the peak demand periods. Demand side management (DSM) is a potential and promising approach for mitigation of the resulting impacts. In this work, we developed an autonomous DSM strategy for optimal charging of EVs to minimize the charging cost and we conducted a simulation study to evaluate the impacts to the grid operation. The proposed approach only requires a one way communicated incentive. Real profiles from an Austrian study on mobility behavior are used to simulate the usage of the EVs. Furthermore, real smart meter data are used to simulate the household base load profiles and a real low voltage grid topology is considered in the load flow simulation. Day-ahead electricity stock market prices are used as the incentive to drive the optimization. The results for the optimum charging strategy is determined and compared to uncontrolled EV charging. The results for the optimum charging strategy show a potential cost saving of about 30.8% compared to uncontrolled EV charging. Although autonomous DSM of EVs achieves a shift of load as pursued, distribution grid operation may be substantially affected by it. We show that in the case of real time price driven operation, voltage drops and elevated peak to average powers result from the coincident charging of vehicles during favourable time slots.
Selbst sicher sein
(2019)