Betonbearbeitung mit hydraulischen Anbaufräsen

Der Fokus der Arbeit liegt durch die Berücksichtigung einer Verwendung als Rettungsgerät nicht nur auf dem Abbaugerät, sondern auch auf dessen Wirkung auf den bearbeiteten Gegenstand. Die Studie fußt auf großmaßstäblichen Versuchen an Betonquadern mit einer handelsüblichen Anbaufräse. Die entdeckten Zusammenhänge widersprechen der gängigen Auffassung vom Fräsvorgang; ein eigenes revidiertes Modell wird vorgestellt. Ferner liefert die Studie etliche Anhaltspunkte zur Optimierung der Frästechnik

Proximal Policy Optimization for Tracking Control Exploiting Future Reference Information

In recent years, reinforcement learning (RL) has gained increasing attention in control engineering. Especially, policy gradient methods are widely used. In this work, we improve the tracking performance of proximal policy optimization (PPO) for arbitrary reference signals by incorporating information about future reference values. Two variants of extending the argument of the actor and the critic taking future reference values into account are presented. In the first variant, global future reference values are added to the argument. For the second variant, a novel kind of residual space with future reference values applicable to model-free reinforcement learning is introduced. Our approach is evaluated against a PI controller on a simple drive train model. We expect our method to generalize to arbitrary references better than previous approaches, pointing towards the applicability of RL to control real systems

Random Migration and Signal Integration Promote Rapid and Robust T Cell Recruitment

To fight infections, rare T cells must quickly home to appropriate lymph nodes (LNs), and reliably localize the antigen (Ag) within them. The first challenge calls for rapid trafficking between LNs, whereas the second may require extensive search within each LN. Here we combine simulations and experimental data to investigate which features of random T cell migration within and between LNs allow meeting these two conflicting demands. Our model indicates that integrating signals from multiple random encounters with Ag-presenting cells permits reliable detection of even low-dose Ag, and predicts a kinetic feature of cognate T cell arrest in LNs that we confirm using intravital two-photon data. Furthermore, we obtain the most reliable retention if T cells transit through LNs stochastically, which may explain the long and widely distributed LN dwell times observed in vivo. Finally, we demonstrate that random migration, both between and within LNs, allows recruiting the majority of cognate precursors within a few days for various realistic infection scenarios. Thus, the combination of two-scale stochastic migration and signal integration is an efficient and robust strategy for T cell immune surveillance

Perspektive zur Höherauslastung des Verteilernetzes mit Gleichstrom (DC): (Stand: 28.03.2023)

Die klimapolitisch bedingte Transformation des elektrischen Energiesystems, bei gleichzeitiger Elektrifizierung sämtlicher Sektoren, führt zu einem deutlich gesteigertem Bedarf an Verteilnetzkapazitäten. Der Ausbau der elektrischen Infrastruktur kann jedoch nicht zuletzt aufgrund komplizierter und verzögerter Genehmigungsverfahren mit dem Integrationstempo neuer Erzeuger und Lasten mithalten. Eine Höherauslastung der Bestandsnetze könnte eine zusätzliche schnell umsetzbare Abhilfe bieten, um den Netzausbaubedarf zu reduzieren oder zeitlich in die Zukunft zu verlagern. Dabei bietet vor allem die Gleichstromtechnologie vielseitige und vielversprechende Lösungsansätze zur Höherauslastung von Verteilnetzen. Dieses Positionspapier gibt einen Überblick über technologische und methodische Ansätze zur Höherauslastung von Bestandsnetzen mit dem Fokus auf der Gleichstromtechnologie. Dabei werden wesentliche betriebliche und physikalische Vorteile der Gleichstromtechnik erläutert und in zwei exemplarischen Fallstudien demonstriert. Dadurch wird der Einsatz der Gleichstromtechnologie als sinnvolle Ergänzung zum herkömmlichen Verteilnetzausbau nachgewiesen

Extended Abstracts of the Second Privacy Enhancing Technologies Convention (PET-CON 2008.1)

PET-CON, the Privacy Enhancing Technologies Convention, is a forum for researchers, students, developers, and other interested people to discuss novel research, current developments and techniques in the area of Privacy Enhancing Technologies. PET-CON was first conceived in June 2007 at the 7th International PET Symposium in Ottawa, Canada. The idea was to set up a bi-annual convention in or nearby Germany to be able to meet more often than only once a year at some major conference

Performance of the ESC 0/1-h and 0/3-h Algorithm for the Rapid Identification of Myocardial Infarction Without ST-Elevation in Patients With Diabetes

Patients with diabetes mellitus (DM) have elevated levels of high-sensitivity cardiac troponin (hs-cTn). We investigated the diagnostic performance of the European Society of Cardiology (ESC) algorithms to rule out or rule in acute myocardial infarction (AMI) without ST-elevation in patients with DM.; We prospectively enrolled 3,681 patients with suspected AMI and stratified those by the presence of DM. The ESC 0/1-h and 0/3-h algorithms were used to calculate negative and positive predictive values (NPV, PPV). In addition, alternative cutoffs were calculated and externally validated in 2,895 patients.; In total, 563 patients (15.3%) had DM, and 137 (24.3%) of these had AMI. When the ESC 0/1-h algorithm was used, the NPV was comparable in patients with and without DM (absolute difference [AD] -1.50 [95% CI -5.95, 2.96]). In contrast, the ESC 0/3-h algorithm resulted in a significantly lower NPV in patients with DM (AD -2.27 [95% CI -4.47, -0.07]). The diagnostic performance for rule-in of AMI (PPV) was comparable in both groups: 0/1-h (AD 6.59 [95% CI -19.53, 6.35]) and 0/3-h (AD 1.03 [95% CI -7.63, 9.7]). Alternative cutoffs increased the PPV in both algorithms significantly, while improvements in NPV were only subtle.; Application of the ESC 0/1-h algorithm revealed comparable safety to rule out AMI comparing patients with and without DM, while this was not observed with the ESC 0/3-h algorithm. Although alternative cutoffs might be helpful, patients with DM remain a high-risk population in whom identification of AMI is challenging and who require careful clinical evaluation