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Contact Tracing with the Exposure Notification Framework in the German Corona-Warn-App
No full textDigital Contact Tracing (CT) protocols based on Bluetooth are best implemented at the system level to save resources and preserve security aspects. Combined with a government-monitored software platform, these CT-protocols can then be used to support controlling pandemics such as COVID-19. However, it is unclear how these protocols have to be parameterized to ensure the most accurate and reliable CT.This paper describes how we derived optimal parameters for a decentralized CT from extensive measurement campaigns that we carried out together with Deutsche Telekom (DT) and SAP under the supervision of the Robert Koch Institut (RKI). We examined the Google/Apple Exposure Notification Framework (ENF), which in combination with the front-end, i.e., the German Corona-Warn-App (CWA), enables digital CT in Germany. With centimeter accurate optical reference systems we show that optimal parameters are application-specific. However, they cause impractical high resource costs. In contrast, optimized general parameters offer an everyday compromise between energy costs, applicability, accuracy, and reliability of the ENF
Design of a Contactless Vital-Signal Sensor based on Six-Port Technology and Experiment of WiFi Interference
No full text484487This paper presents a contactless vital-signal sensor based on the six-port concept. A prototype including the digital signal processing (DSP) is designed and implemented. The RF hardware consists of an in-house produced six-port junction and power detectors. The DSP involves the empirical mode decomposition (EMD) from the Hilbert-Huang transform (HHT) to acquire the vital signals from the measured raw data. The operation frequency is in the unlicensed 2.4 GHz industrial, scientific, and medical (ISM) band, where it coexists with other communication standards, e.g. WiFi and Bluetooth. The WiFi communication link in particular occupies a wide spectrum in this band due to high data rate. Therefore, a series of experiments regarding the interference of WiFi with the prototype is carried out, and studied. Maximum measured distance between the sensor and a person under test is ≈4 m. According to our experiment, the sensor can still extract the vital signal when the WiFi communication is nearby
Simulation of geometrical errors during application of a confocal sensor system for the measurement of large components with high aspect ratios
No full text173182Machining of large components for the aerospace industry requires, in addition to sophisticated machining strategies a targeted monitoring of the machining quality due to the enormous demands on precision. For the acquisition of the as-is geometry after single machining steps, a non-contact system based on a confocal chromatic sensor was developed, with whose help the as-is geometry can be compared with the target geometry even in deep cavities at aspect ratios up to 40. The sensor system is coupled with the standard interfaces to a machine tool and performs measuring cycles based on modified NC programs. Data acquisition is done with a control-connected EDGE system. The result of the target/as-is comparison is the basis for CAM planning for subsequent machining. In addition to the design of the measuring system and the integration into the ecosystem of the machine system, a concept to calibrate the measuring system for operation on the machine tool was developed. Based on a simulation model of the measurement system various aspects of the calibration approach were analysed
Miniaturized Infrared lenses by wafer bonding technologies
No full text234237This paper presents a novel technology platform to fabricate miniaturized Silicon optics by embedding hundreds of Si spheres on wafer level. The exact curvature of spherical preforms which are subsequently grinded to form a plano-convex lens, promises excellent optical properties for IR spot detectors and could eliminate the need for expensive 100 % optical measurements in manufacturing. The transmission properties of the Si lenses were evaluated using a commercially available IR sensor. The technology provides a new dimension to product designers on the system level and could ease the integration of IR sensors into consumer elec tronics
Air-coupled CMUTs beyond 2 MHz
No full textThe present work sets out the design, fabrication, and characterization of air-coupled capacitive micromachined ultrasonic transducers (CMUTs) operating beyond 2 MHz for high-resolution sensing. The development of these devices is founded upon a robust CMUT process at Fraunhofer IPMS that utilizes a sacrificial-cavity approach. The plates are arranged in a hexagonal configuration and are connected in parallel, with the objective of enhancing transmit power and receive sensitivity. Laser-Doppler vibrometry (LDV) was employed to confirm uniform plate motion with phase variations at the array edges and a central-plate peak deflection of 475 nm at 2.26 MHz. Frequency response analysis demonstrates a small deviation between transmit and receive optimal frequencies, thereby supporting pulse-echo operation with the same device. Furthermore, the analysis reveals the presence of a higher, air-damped mode near 5.6 MHz. Utilizing a compact control system for sensor evaluation up to ±200 V and pulse drive from 0.01 MHz to 25 MHz, we demonstrate the efficacy of reliable pulse-echo measurements at a distance up to 40 mm with the implementation of averaging. Our results establish practical megahertz-range air-coupled CMUT sensing and provide an accessible instrumentation path for laboratory and feasibility studies, enabling applications in small-object detection, robotic gripping, non-destructive evaluation, and surface characterization
Component Sizing and Energy Management of Electric-Hydrogen Hybrid Energy Storage Systems for Solid-State-Transformer-Based Meshed Networks
No full textThis paper proposes a meshed distribution network architecture based on solid-state transformers (SSTs) to integrate various distributed energy resources (DERs) such as photovoltaic (PV) systems, battery energy storage systems (BESSs), and hydrogen energy storage systems (HESSs) composed of fuel cells, electrolyzers, and hydrogen tanks. Moreover, a co-design framework is developed to optimize the component sizing and energy management of an electric-hydrogen hybrid energy storage system (ESS) including a BESS and an HESS. The objective of the optimization framework is to minimize the total cost of the hybrid ESS categorized as the investment cost associated with component sizing and the operating cost related to energy management. In particular, this optimization framework explicitly considers the losses of the BESS, the HESS, and the distribution lines to more comprehensively evaluate the total cost of the hybrid ESS. In addition, convex transformations are introduced to reformulate the nonlinear equality constraints and the discrete inequality constraints into convex forms. Therefore, convex programming can be utilized to solve the optimization framework efficiently to obtain a globally optimal solution. The meshed network and the co-design framework are evaluated using a modified 59-node low-voltage AC (LVAC) grid model in the German SimBench dataset. Comprehensive simulations are performed using a 12-day dataset and a 366-day dataset of the year of 2016. Simulation results show that the meshed network leads to a better economy and a better voltage stability compared to the radial network. The optimization framework properly determines the power distribution between the BESS and the HESS based on the constraints and bounds of the ESS states such as the battery state of charge (SOC). In addition, the optimization framework is scalable and can be used to address the component sizing and energy management issues in large-scale distribution networks.Online Firs
Umbrella Data Management Plans to Integrate FAIR Data : Lessons From the ISIDORe and BY-COVID Consortia for Pandemic Preparedness
No full textThe Horizon Europe project ISIDORe is dedicated to pandemic preparedness and responsiveness research. It brings together 17 research infrastructures (RIs) and networks to provide a broad range of services to infectious disease researchers. An efficient and structured treatment of data is central to ISIDORe’s aim to furnish seamless access to its multidisciplinary catalogue of services, and to ensure that users’ results are treated FAIRly. ISIDORe therefore requires a data management plan (DMP) covering both access management and research outputs, applicable over a broad range of disciplines, and compatible with the constraints and existing practices of its diverse partners. Here, we describe how, to achieve that aim, we undertook an iterative, step-by-step, process to build a community-approved living document, identifying good practices and processes, on the basis of use cases, presented as proof of concepts. International fora such as the RDA and EOSC, and primarily the BY-COVID project, furnished registries, tools and online data platforms, as well as standards, and the support of data scientists. Together, these elements provide a path for building an umbrella, FAIR-compliant DMP, aligned as fully as possible with FAIR principles, which could also be applied as a framework for data management harmonisation in other large-scale, challenge-driven projects. Finally, we discuss how data management and reuse can be further improved through the use of knowledge models when writing DMPs and, how, in the future, an inter-RI network of data stewards could contribute to the establishment of a community of practice, to be integrated subsequently into planned trans-RI competence centres.2
Security Engineering for Ambient Intelligence: A Manifesto
No full text36913712The scenarios of ambient intelligence introduce a new computing paradigm and set new challenges for the design and engineering of secure and dependable systems. This chapter describes SERENITY, a comprehensive approach to overcome those problems. The key to success in this scenario is to capture security expertise in such a way that it can be supported by automated means. SERENITY’s integral model of ADD—security and dependability (S&D) considers both static and dynamic aspects by relying in two main innovations: (1) the enhanced notion of S&D patterns and integration schemes; and (2) the computer aided run-time monitoring of the implemented security solutions. The combination of these innovations lays the foundations of an integrated, solid, flexible, and practical S&D framework for AmI ecosystems. The chapter aims at clarifying the challenges introduced in AmI ecosystems and pointing out directions for research in the different areas involved
A perspective of randomness in a clinical test of olfactory performance
No full textRandom walks describe stochastic processes characterized by a sequence of unpredictable changes in a random variable with no correlation to past changes. This report describes the random walk component of a clinical sensory test of olfactory performance. The precise definition of this stochastic process allows the establishment of precise diagnostic cut-offs for the identification of olfactory loss. Within the Sniffin`Sticks olfactory test battery, odor discrimination (D) and odor identification (I) are assessed by four- and three-alternative forced-choice designs, respectively. Meanwhile, the odor threshold (T) test integrates a three-alternative forced-choice paradigm within a staircase paradigm with seven turning points. We explored this paradigm through computer simulations and provided a formal description. The odor threshold assessment test consists of two sequential components, the first of which sets the starting point for the second. Both parts can be characterized as biased random walks with significantly different probabilities of moving to higher (11%) or lower (89%) values. The initial odor concentration step for the first phase of the test and the length of the subsequent random walk in the second phase significantly affect the probability of randomly achieving high test scores. Changing the odor concentration from where the starting point determination for the second test part begins has raised the current cut-off for anosmia, represented as T + D + I < 16, from the 87th quantile of random test scores to the 97th quantile. Analogous findings are likely applicable to other sensory tests that use the staircase paradigm characterized as random walk.13
Effect of carbon content and metal binder type on phase composition in high-entropy carbide-based hardmetals
No full textA high-entropy carbide (HEC) powder of the composition (Ti,Nb,Ta,Mo,W)C was prepared by milling of individual metal powders with graphite and synthesis at 1900 °C in vacuum. This HEC powder served with varying carbon contents as the hard phase in HEC-Fe and HEC-Ni hardmetals prepared by standard powder metallurgy techniques. This study focused on the influence of the binder metal and carbon content on the microstructure and phase composition of these hardmetals. Although the synthesised hard phase powder was a single-phase HEC with a cubic FCC lattice, secondary phases formed during sintering of hardmetals mixtures. Depending on the binder metal and carbon content, phases such as a M6C η-phase, W- and Mo- based MxCy carbides and free carbon appeared in the microstructure. The experimental results (XRD, SEM and EDS) were closely matching the thermodynamic predictions. Increased carbon content inhibited η-phase formation in HEC-based hardmetals with Fe binder, whereas, notably, η-phase was neither predicted nor observed in HEC-Ni hardmetals. However, the (W,Mo)xCycarbide was predicted and formed in high‑carbon HEC-Fe and in all HEC-Ni hardmetals. Both HEC and (W,Mo)xCy carbide showed a tendency to form core-rim structures. With its effect on microstructure and phase composition, carbon content affected also the mechanical properties of hardmetals: in general, higher carbon content reduced hardness and increased fracture toughness.13