Datenschutz bei kleinräumigen Auswertungen – Anforderungen und Grenzwerte

Wissenschaft, Wirtschaft und Verwaltung sind in zunehmendem Maße auf georeferenzierte Informationen angewiesen. Dabei wächst auch der Bedarf an möglichst kleinräumigen Auswertungen, sei es zu Planungszwecken, zur Optimierung von Geschäftsmodellen oder zur Verbesserung wissenschaftlicher Analysen. Die Informationstechnik sowie das vorhandene Datenmaterial an Geobasis- und Geofachdaten versetzen datenverarbeitende Unternehmen in die Lage, derartige Auswertungen mit überschaubarem Aufwand durchzuführen. Dabei sind die Möglichkeiten, ganz unterschiedliche georeferenzierte Informationen aus verschiedenen Quellen zusammenzuführen, miteinander zu verschneiden, daraus neue Erkenntnisse zu gewinnen und die so gewonnenen Informationen wiederum mit weiteren Daten zu verknüpfen, scheinbar unbegrenzt. Die unendlichen technologischen Möglichkeiten treffen jedoch auf ein vorhandenes Umfeld rechtlicher Rahmenbedingungen, in das sie eingebettet werden müssen. Geht es um die Verarbeitung georeferenzierter Informationen, bildet das Datenschutzrecht einen wichtigen regulatorischen Rahmen, in dem sich kleinräumige Auswertungen bewegen müssen. Dabei fällt auf, dass ungeachtet des hohen Datenschutzbewusstseins in Deutschland im Zusammenhang mit der Verarbeitung geografischer Informationen eine eher geringe Sensibilität für den Datenschutz vorhanden ist. Öffentliche Debatten, z. B. zu Panoramadiensten wie Google Street View, haben auf der anderen Seite für eine gewisse Verunsicherung gesorgt. Schnell steht der Vorwurf im Raum, die datenschutzrechtlichen Regeln behindern die technologische Entwicklung. Der folgende Beitrag soll deshalb einige wichtige datenschutzrechtliche Fragen im Zusammenhang mit der Verarbeitung georeferenzierter Informationen beleuchten

Models to describe the thermomechanical material properties of early age concrete

Die Kenntnis der thermomechanischen Materialeigenschaften jungen Betons ist für zahlreiche Anwendungsfälle von Bedeutung, bspw. für die Prognose von Eigen- und Zwangsspannungen infolge Hydratationswärme, für die Planung von Abläufen auf Baustellen und in Fertigteilwerken oder für die Optimierung von Betonrezepturen im Hinblick auf einen möglichst effizienten Rohstoffeinsatz. Im Rahmen der vorliegenden Arbeit werden die thermomechanischen Materialeigenschaften verschiedener Betone im jungen Alter experimentell untersucht. Darauf aufbauend werden neue Materialmodelle entwickelt bzw. existierende Modelle angepasst. Darüber hinaus werden die Materialmodelle in eine Finite-Elemente-Software implementiert, wodurch eine realitätsnahe Prognose der Temperatur- und Spannungsentwicklung infolge der Hydratationswärmefreisetzung in erhärtenden Betonbauteilen möglich wird. Das Versuchsprogramm umfasst Untersuchungen zur Wärmefreisetzung und Festigkeitsentwicklung sowie zum Verformungsverhalten junger Betone unter Kurz- und Langzeitbeanspruchung. Als Einflussfaktoren werden die Betonzusammensetzung, die Erhärtungstemperatur und die Belastungsgeschichte untersucht. Die Versuchsergebnisse dienen zur Entwicklung bzw. Anpassung von Modellen zur Beschreibung der Materialeigenschaften von Beton im jungen Alter. Zur Beschreibung der zeitlichen Entwicklung der mechanischen Kurzzeiteigenschaften wird ein Ansatz auf Basis einer Exponentialfunktion gewählt, der durch die Kopplung der Parameter eine realitätsnahe Beschreibung der Eigenschaften mit verhältnismäßig wenigen Parametern möglich macht. Zur Beschreibung des viskoelastischen Materialverhaltens dient ein rheologisches Modell bestehend aus vier Maxwelleinheiten und einer Feder, jeweils mit alternden Materialkennwerten, das in der Lage ist, das Verformungsverhalten des Betons unter konstanter und zeitlich veränderlicher Spannung realitätsnah zu beschreiben, was durch den Vergleich mit entsprechenden Versuchsdaten belegt wird. Die entwickelten und experimentell kalibrierten Materialmodelle werden in eine kommerzielle Finite-Elemente-Software implementiert. Mit zwei Berechnungsbeispielen wird beispielhaft die Anwendung der Modelle zur rechnerischen Prognose der Temperatur- und Spannungsentwicklung in erhärtenden Betonbauteilen gezeigt.The knowledge of the thermomechanical material properties of early age concrete is of importance for many applications, eg. for the calculation of restraint stresses due to hydration heat, for the planning of optimization processes on building sites and in precast plants or for the optimization of concrete mixes with focus on an efficient use of raw materials. In the present work, the thermomechanical properties of various concretes at an early age are investigated experimentally. Based on the experimental results material models are developed or adapted. Moreover, the material models are implemented in a finite element software. With this, a more realistic prediction of the temperature and stress development caused by hydration heat in hardening concrete structures is possible. The experimental program includes the testing of the heat release, the strength development and the stress-strain behavior of early age concrete under short- and long-term stress. Influences of the concrete composition, the curing temperature and the loading history are investigated. The test results are used for development or adaptation of models to describe the material properties of concrete at an early age. To describe the time evolution of the mechanical properties an exponential function was chosen, which may describe the evolution of the properties realistically with a relatively low number of parameters. For the description of the viscoelastic material behavior a rheological model with aging spring and dashpot parameters is developed. This model is able to describe the stress-strain behavior of concrete under constant and time-varying stress realistically which is proven by a comparison with experimental data. The developed and experimentally calibrated material models are implemented into a commercial finite element software. Two calculation examples show that this software may then be used for the computational prediction of temperature and stress development in hardening concrete structures

Adjoint method and inverse design for diffractive beam splitters

Diffractive optical elements with a large diffraction angle require feature sizes down to sub-wavelength dimensions, which require a rigorous electromagnetic computational model for calculation. However, the computational optimization of these diffractive elements is often limited by the large number of design parameters, making parametric optimization practically impossible due to large computation times. The adjoint method allows calculating the gradient of the target function with respect to all design variables with only two electromagnetic simulations, thus enabling gradient optimization. Here, we present the adjoint method for modeling wide-angle diffractive optical elements like 7x7 beam splitters with a maximum 53{\deg} diffraction angle and a non-square 5x7 array generating beam splitter. After optimization we obtained beam splitter designs with a uniformity error of 16.35% (7x7) and 6.98% (5x7), respectively. After reviewing the experimental results obtained from fabricated elements based on our designs, we found that the adjoint optimization method is an excellent and fast method to design wide-angle diffractive fan-out beam-splitters.Comment: 8 pages, 3 figures, submitted to SPIE LASE 202

Development of a computational model for the flow analysis of an overflow gate and a rotating water wheel

2-Phasen-Strömungen spielen im Wasserbau sowohl bei der Überströmung von Verschlussorganen als auch bei der Durchströmung von Schaufelwasserrädern eine wesentliche Rolle für die Belastungsermittlung und die konstruktive Durchbildung. Ziel dieser Arbeit ist es, mittels numerischer Berechnungen einen Einblick in das Strömungsgeschehen am Schütz und im Wasserrad zu erlangen. Die Beschreibung der am Strömungsgeschehen beteiligten Fluidphasen erfolgt anhand der inkompressiblen Navier-Stokes-Gleichungen in den primären Variablen Geschwindigkeit und Druck. Unter Hinzunahme einer Level-Set-Funktion in Verbindung mit einer regularisierten Heaviside-Funktion können sowohl Lage und Bewegung der Grenzfläche als auch ein stetiger Übergang zwischen den Materialparametersätzen abgebildet werden. Zur Diskretisierung des Fluidgebietes kommt die Raum-Zeit-Finite-Elemente-Methode zur Anwendung. Damit wird die Veränderlichkeit des Strömungsgebietes implizit bei der Abbildung auf das Referenzgebiet erfasst. Die Berücksichtigung der stetigen Drehbewegung des Wasserrades erfolgt mit Hilfe der Shear-Slip-Mesh-Update-Methode als diskontinuierlichem Netzbewegungsverfahren. Im Rahmen der numerischen Untersuchung der Strömungsvorgänge am vom Modellwasserrad losgelösten Regulierschütz mit Kreisbogengeometrie können fünf voneinander unterscheidbare Strömungszustände identifiziert werden. Für diese erfolgt eine Analyse der Wechselwirkungsvorgänge beider Fluidphasen im Bereich des Schützrückens und im angrenzenden Tosbecken. Für das Modellwasserrad erfolgt die numerische Untersuchung des Befüllungs- und Entleerungsvorganges. Neben dem Strömungsgeschehen in der Wasserphase wird dabei auch der Einfluss der Luftphase insbesondere bei der Be- und Entlüftung der Schaufelräume berücksichtigt. Sowohl für die Schützüberströmung als auch für die Durchströmungsvorgänge am Wasserrad wurden begleitende experimentelle Untersuchungen zur Validierung durchgeführt. Diese geben auch einen über die numerisch auflösbaren Skalen hinausgehenden Einblick in das Interaktionsverhalten der Fluidphasen. Die mit Hilfe des entwickelten Finite-Elemente-Programmes durchgeführten numerischen Untersuchungen haben sowohl am Schütz als auch beim Wasserrad die Beobachtung und Analyse von charakteristischen Strömungsphänomenen ermöglicht, für die bisher keine oder nicht in dem Umfang entsprechende Daten vorhanden waren.Two phase flows are the dominant flow regime in hydraulic engineering regarding the overflow at gates as well as the throughflow in water wheels. The aim of this thesis is to gain insight into the flow behaviour at overflow gates and in rotating water wheels by means of a computational model. Both fluid phases are modelled using the incompressible Navier-Stokes equations with velocity and pressure as primal variables. Position and movement of the interface are described via a level set function in conjunction with a Heaviside function allowing a continuous transition between both material parameter sets. The discretisation is performed by application of the space-time finite element method in combination with the shear-slip mesh-update method as discontinuous mesh moving technique for capturing the rotation of the water wheel. The numerical analysis of the two phase flow at the overflow gate reveals five distinct flow states. An in-depth analysis of these states is performed with specific focus on the downstream area beginning at the gate top as well as the plunge pool. Besides its independent use, the overflow gate serves as adjustment device regulating the inflow into the water wheel. Therefore, a numerical analysis of the filling and discharge process of the rotating water wheel is conducted as well. Among others the numerical analysis of the two-phase flow in the water wheel highlights the significant influence of the air phase regarding the ventilation of the interspaces. Furthermore, the effects onto the flow field of the blades passing closely the regulating gate can be quantified. The numerical analyses of overflow gate and water wheel are accompanied by physical experiments. Besides validation purpose additional insight is gained related to the flow characteristics which could not be resolved numerically. Based on the developed computational model the performed numerical analyses yield insight into characteristic flow patterns at overflow gates and especially in water wheels, for which no or not enough numerical data has been available until now

SensorCloud: Towards the Interdisciplinary Development of a Trustworthy Platform for Globally Interconnected Sensors and Actuators

Although Cloud Computing promises to lower IT costs and increase users' productivity in everyday life, the unattractive aspect of this new technology is that the user no longer owns all the devices which process personal data. To lower scepticism, the project SensorCloud investigates techniques to understand and compensate these adoption barriers in a scenario consisting of cloud applications that utilize sensors and actuators placed in private places. This work provides an interdisciplinary overview of the social and technical core research challenges for the trustworthy integration of sensor and actuator devices with the Cloud Computing paradigm. Most importantly, these challenges include i) ease of development, ii) security and privacy, and iii) social dimensions of a cloud-based system which integrates into private life. When these challenges are tackled in the development of future cloud systems, the attractiveness of new use cases in a sensor-enabled world will considerably be increased for users who currently do not trust the Cloud.Comment: 14 pages, 3 figures, published as technical report of the Department of Computer Science of RWTH Aachen Universit

User-driven Privacy Enforcement for Cloud-based Services in the Internet of Things

Internet of Things devices are envisioned to penetrate essentially all aspects of life, including homes and urbanspaces, in use cases such as health care, assisted living, and smart cities. One often proposed solution for dealing with the massive amount of data collected by these devices and offering services on top of them is the federation of the Internet of Things and cloud computing. However, user acceptance of such systems is a critical factor that hinders the adoption of this promising approach due to severe privacy concerns. We present UPECSI, an approach for user-driven privacy enforcement for cloud-based services in the Internet of Things to address this critical factor. UPECSI enables enforcement of all privacy requirements of the user once her sensitive data leaves the border of her network, provides a novel approach for the integration of privacy functionality into the development process of cloud-based services, and offers the user an adaptable and transparent configuration of her privacy requirements. Hence, UPECSI demonstrates an approach for realizing user-accepted cloud services in the Internet of Things.Comment: 6 pages, 2 figures, 1 listing. The 2nd International Conference on Future Internet of Things and Cloud (FiCloud-2014

Implementing Inkjet Printed Transparent Conductive Electrodes in Solution Processed Organic Electronics

Through the use of solution-based materials, the field of printed organic electronics has not only made new devices accessible, but also allows the process of manufacture to move toward a high throughput industrial scale. However, while solution-based active layer materials in these systems have been studied quite intensely, the printed electrodes and specifically the transparent conductive anode have only relatively recently been investigated. In this progress report, the use of metal nanoparticles within printed organic electronic devices is highlighted, specifically their use as replacement of the commonly used indium tin oxide transparent conductive electrode within organic photovoltaics (OPVs) and organic light emitting diodes (OLEDs). A cross fertilization between the applications is expected since an OPV device is essentially an inversely operated OLED. This report aims to highlight the use of inkjet-printed nanoparticles as cost-effective electrodes for printed optoelectronic applications and discusses methods to improve the conductive and interfacial properties. Finally, in an outlook, the use of these types of metal nanoparticle inks to manipulate light management properties, such as outcoupling, in the device is investigated

A guide to qualitative haze measurements demonstrated on inkjet-printed silver electrodes for flexible OLEDs

The search for alternative transparent electrodes to the commonly used indium tin oxide (ITO) in optoelectronic devices has led to solution-based approaches based on inkjet printing. As an additive manufacturing technique that allows drops to be positioned only where necessary, inkjet printing shows reduced waste of starting material compared to other methods such as spin coating. As a result, functional materials can be both coated and structured without the need for masks or lithographic pre-patterning of the substrate. For this contribution, we utilized a particle-free silver ink to produce a transparent electrode by inkjet printing. After printing, the silver ions were reduced to metallic silver by an argon plasma. The process takes place at low temperatures (ca. 40 – 50°C), making it suitable for use with flexible substrates, which are often temperature-sensitive. The printed silver layers show good electrical conductivity and optical transmittance, with a crystalline grain structure being formed and maintained during the metallization process. This structure forms a self-organized nanometer-size grid, whose structure allows light to pass through. Due to its nano-structured property, the haze of the electrode was investigated using a simple experimental setup based on a light source shining through the electrode and analyzing the size of the projected pattern. Such qualitative assessment can be a useful indication of the quality of the electrode and we provide details on how to replicate this setup. The final electrodes were implemented in solution-processed OLEDs, which showed bright luminance and overall low haze compared to ITO-based reference devices.Peer Reviewe

ITO free OLEDs utilizing inkjet printed and low temperature plasma sintered Ag electrodes

We report an inkjet printed indium tin oxide ITO free electrode made from a particle free silver ink. After printing, an argon plasma is used to reduce the silver ions in the ink to metallic silver. This process does not require high temperatures and is therefore suitable for use with temperature sensitive substrates. Printed silver layers show good optical transmittance and electrical conductivity. To demonstrate the capabilities of the electrodes, inverted ITO free organic light emitting diodes OLEDs were produced via solution processing. In terms of luminance and efficacy, the devices containing the printed electrodes show improved luminance and current efficacy compared to ITO based reference devices. When fabricated with flexible substrates, the printed OLEDs show high bending stability, enabling flexible application

Using Combinatorial Inkjet Printing for Synthesis and Deposition of Metal Halide Perovskites in Wavelength‐Selective Photodetectors

Metal halide perovskites have received great attention in recent years, predominantly due to the high performance of perovskite solar cells. The versatility of the material, which allows the tunability of the bandgap, has led to its use in light-emitting diodes, photo, and X-ray detectors, among other optoelectronic device applications. Specifically in photodetectors, the tunability of the bandgap allows fabrication of spectrally selective devices. Utilizing a combinatorial inkjet printing approach, multiple perovskite compositions absorbing at specific wavelengths in a single printing step are fabricated. The drop-on-demand capabilities of inkjet printing enable the deposition of inks in a precise ratio to produce specific perovskite compositions in the printed thin film. By controlling the halide ratio in the compositions, a mixed halide gradient ranging from pure MAPbI3 via MAPbBr3 to MAPbCl3 is produced. The tunability in the absorption onset from 410 to 790 nm is demonstrated, covering the whole visible spectrum, with a precision of 8 nm steps for MAPb(BrxCl1−x)3 compositions. From this range of mixed halide perovskites, photodetectors which show spectral selectivity corresponding to the measured absorption onset are demonstrated, paving the way for use in a printed visible light spectrometer without the need for a dispersion element.Peer Reviewe