Privacy Amplification via Importance Sampling

We examine the privacy-enhancing properties of subsampling a data set via importance sampling as a pre-processing step for differentially private mechanisms. This extends the established privacy amplification by subsampling result to importance sampling where each data point is weighted by the reciprocal of its selection probability. The implications for privacy of weighting each point are not obvious. On the one hand, a lower selection probability leads to a stronger privacy amplification. On the other hand, the higher the weight, the stronger the influence of the point on the output of the mechanism in the event that the point does get selected. We provide a general result that quantifies the trade-off between these two effects. We show that heterogeneous sampling probabilities can lead to both stronger privacy and better utility than uniform subsampling while retaining the subsample size. In particular, we formulate and solve the problem of privacy-optimal sampling, that is, finding the importance weights that minimize the expected subset size subject to a given privacy budget. Empirically, we evaluate the privacy, efficiency, and accuracy of importance sampling-based privacy amplification on the example of k-means clustering.Comment: Under review for NeurIPS 202

Evolutionary optimized 3D WiFi antennas manufactured via laser powder bed fusion

The swift and automated design of antennas remains a challenging aspect in research due to the specific design needs for individual applications. Alterations in resonance frequency or boundary conditions necessitate time-consuming re-designs. Though the application of evolutionary optimization and generative methods in general to antenna design has seen success, it has been mostly restricted to two-dimensional structures. In this work, we present an approach for designing three-dimensional antennas using a genetic algorithm coupled with a region-growing algorithm - to ensure manufacturability - implemented in Matlab manufactured via laser powder bed fusion (LPBF). As a simulation tool for optimization CST is used. The antenna has been optimized in a completely automated manner and was produced using the metal 3D printing technology LPBF and aluminium based AlSi10Mg powder. The presented concept, which builds upon previous two-dimensional techniques, allows for significant flexibility in design, adapting to changing boundary conditions, and avoiding the geometric restrictions seen in prior methods. The optimized antenna has a size of 3.01 cm × 3.43 cm × 1.67 cm and was measured in an anechoic chamber. According to measurements a minimum reflection coefficient of -19.95 dB at 2.462 GHz and a bandwidth of 308.8 MHz are observed. CST simulation results predict an efficiency of 98.91% and the maximum antenna gain is measured at 2.45 GHz to be 3.27 dB i. Simulations made with CST and Ansys HFSS and measurements are in excellent agreement with a deviation of the resonance frequency of only 0.13% , thus further establishing genetic algorithms as a highly viable option for the design of novel antenna structures.Austrian Agency for Education and Internationalisation (OeAD) [CZ 03/2022]; European Regional Development Fund (ERDF); Austria Wirtschaftsservice Gesellschaft (AWS) [P2372773]; University of Innsbruc

Eosinophil deficiency promotes aberrant repair and adverse remodelling following acute myocardial infarction

In ST-segment elevation myocardial infarction of both patients and mice, there was a decline in blood eosinophil count, with activated eosinophils recruited to the infarct zone. Eosinophil deficiency resulted in attenuated anti-inflammatory macrophage polarization, enhanced myocardial inflammation, increased scar size, and deterioration of myocardial structure and function. Adverse cardiac remodeling in the setting of eosinophil deficiency was prevented by interleukin-4 therapy

Numerical Optimization of a Fully Cross-Coupled Rectifier Circuit for Wireless Passive Ultra Low Power Sensor Nodes

In the context of the Internet of Things, billions of devices—especially sensors—will be linked together in the next few years. A core component of wireless passive sensor nodes is the rectifier, which has to provide the circuit with sufficient operating voltage. In these devices, the rectifier has to be as energy efficient as possible in order to guarantee an optimal operation. Therefore, a numerical optimization scheme is proposed in this paper, which is able to find a unique optimal solution for an integrated Complementary Metal-Oxide-Semiconductor (CMOS) rectifier circuit with Self-Vth-Cancellation (SVC). An exploration of the parameter space is carried out in order to generate a meaningful target function for enhancing the rectified power for a fixed communication distance. In this paper, a mean conversion efficiency is introduced, which is a more valid target function for optimization than the Voltage Conversion Efficiency (VCE) and the commonly used Power Conversion Efficiency (PCE) and is defined as the arithmetic mean between PCE and VCE. Various trade-offs between output voltage, PCE, VCE and MCE are shown, which provide valuable information for low power rectifier designs. With the proposed method, a rectifier in a low power 55 nm process from Globalfoundries (GF55LPe) is optimized and simulated at −30 dBm input power. A mean PCE of 63.33% and a mean VCE of 63.40% is achieved

Evolutionary algorithms as a tool for shielding design

The paper deals with the shielding enclosure design using evolutionary algorithms without predetermined conditions. The designed shield consists of an array of elements that rep-resent conductive or non-conductive parts. The expected output is to design a shield with sufficient balance between shielding effectiveness and transparency in systems that need an optical line of sight. The wide frequency transparent shielding design is a complex task that researchers so far mostly solved by composite polymers. The authors use a different approach using traditional conductive material and element folding technology. Element assembly is performed by an evolutionary algorithm that decides the properties of the material used and creates the optimal structure to achieve the desired results. The paper describes the design concept for planar shielding with metaheuristics and the preliminary results. © 2022 IEEE.CZ.02.2.69/0.0/0.0/16028/0006243; Univerzita Tomáše Bati ve Zlíně: IGA/CebiaTech/2022/004, IGA/FAI/2022/00

Is the Use of Segways or E-Scooters in Urban Areas a Potential Health Risk? A Comparison of Trauma Consequences

Background and objectives: Electromobility has become increasingly popular. In 2001, Segway personal transporters (Segway) were established for tourists, and e-scooters have been in use since their approval in 2019. The aim of this study was to analyze and compare the types of injuries directly related to the use of Segways and e-scooters, respectively, in a German city and to phrase potential safety advice. Materials and Methods: All patients presenting to our emergency department after Segway incidents were retrospectively analyzed and compared with the prospectively collected cohort of patients following e-scooter incidents. Presented injuries were analyzed by body region and injury severity score (ISS). Epidemiological data were collected. Results: Overall, 171 patients were enrolled. The Segway group included 56 patients (mean age 48 years), and the e-scooter group consisted of 115 patients (mean age 33.9 years). Head injuries (HI) occurred in 34% in the Segway group compared to 52% in the e-scooter group. The ISS was approximately equal for both groups (mean ISS Segway group: 6.9/e-scooter group: 5.6). Conclusions: Since the e-scooter group presented a high number of HI along with a higher likelihood and greater severity of HI, mandatory use of helmets is suggested