To analyze the physical properties arising from indirect magnetic exchange between several magnetic adatoms and between complex magnetic nanostructures on metallic surfaces, the real-space extension of dynamical mean-field theory (R-DMFT) appears attractive as it can be applied to systems of almost arbitrary geometry and complexity. While R-DMFT describes the Kondo effect of a single adatom exactly, indirect magnetic (RKKY) exchange is taken into account on an approximate level only. Here, we consider a simplified model system consisting of two magnetic Hubbard sites ("adatoms") hybridizing with a non-interacting tight-binding chain ("substrate surface"). This two-impurity Anderson model incorporates the competition between the Kondo effect and indirect exchange but is amenable to an exact numerical solution via the density-matrix renormalization group (DMRG). The particle-hole symmetric model at half-filling and zero temperature is used to benchmark R-DMFT results for the magnetic coupling between the two adatoms and for the magnetic properties induced in the substrate. In particular, the dependence of the local adatom and the nonlocal adatom-adatom static susceptibilities as well as the magnetic response of the substrate on the distance between the adatoms and on the strength of their coupling with the substrate is studied. We find both, excellent agreement with the DMRG data even on subtle details of the competition between RKKY exchange and the Kondo effect but also complete failure of the R-DMFT, depending on the parameter regime considered. R-DMFT calculations are performed using the Lanczos method as impurity solver. With the real-space extension of the two-site DMFT, we also benchmark a simplified R-DMFT variant.

Autofocus techniques for synthetic aperture radar (SAR) can improve the image quality substantially. Their high computational complexity imposes a challenge when employing them in runtime-critical implementations. This paper presents an autofocus implementation for stripmap SAR specially optimized for parallel architectures like GPUs. Thorough evaluation using real SAR data shows that the tunable parameters of the algorithm allow to counterbalance runtime and achieved image quality.

Vertical jump height is an important tool to measure athletes' lower body power in sports science and medicine. Several different methods exist to measure jump height, but each has its own limitations. This work proposes a novel way to measure jump height directly, using optical tracking with a single smartphone camera. A parabolic fall trajectory is obtained from this video by tracking a single feature. The parabolic trajectory is then used to partially calibrate the camera and convert pixel measurements into real-world units, allowing the calculation of the achieved height. Comparison to an optical motion capture system yields promising results.

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Broadband powerline communication systems using Orthogonal Frequency Division Multiplexing (OFDM) can utilize existing power lines to transmit data packets alongside power distribution. Recent standards focus towards high speed multi-media in-house streaming. With improvements towards robustness and throughput new standards increase the speed and reliability of in-house powerline systems. A very different approach is the use of powerline communication systems in a deep drilling environment where temperatures of more than 150 • C and pressure levels up to 30 000 psi are present. Typical applications in this environment usually do not require more than several kbit/s per node and are more reliant on a stable and continuous connection. Here, a powerline communication system can reduce the amount of wiring needed and increase communication robustness significantly. This work provides a harsh environment suitable, reliable and standard compliant communication ASIC that is manufactured in XFAB 180 nm Silicon-On-Insulator (SOI) technology allowing operating temperatures of up to 175 • C. The die size is 5.25 mm x 5.25 mm and contains a complete Homeplug 1.0 communication stack with an environment for boot, interfacing and debugging. The data rate is as high as 6.1 Mbit/s using the fastest transmission mode and reaches the theoretical maximum of 0.55 Mbit/s in the robust OFDM (ROBO) mode which is of particular interest for harsh environment applications. To the best of the authors knowledge, this is the first OFDM-based powerline communication ASIC which is particularly designed for harsh environment.