On a Connection between Differential Games, Optimal Control, and Energy-based Models for Multi-Agent Interactions

Game theory offers an interpretable mathematical framework for modeling multi-agent interactions. However, its applicability in real-world robotics applications is hindered by several challenges, such as unknown agents' preferences and goals. To address these challenges, we show a connection between differential games, optimal control, and energy-based models and demonstrate how existing approaches can be unified under our proposed Energy-based Potential Game formulation. Building upon this formulation, this work introduces a new end-to-end learning application that combines neural networks for game-parameter inference with a differentiable game-theoretic optimization layer, acting as an inductive bias. The experiments using simulated mobile robot pedestrian interactions and real-world automated driving data provide empirical evidence that the game-theoretic layer improves the predictive performance of various neural network backbones.Comment: International Conference on Machine Learning, Workshop on New Frontiers in Learning, Control, and Dynamical Systems (ICML 2023 Frontiers4LCD

KYLEO® - Wirkungsweise unter der Lupe

Kyleo® stellt mit zwei bekannten Wirkstoffen ein innovatives und modernes Herbizid zum aktiven Resistenzmanagement dar. In Kyleo® sind 160 g/L 2,4-D und 240 g/L Glyphosat enthalten. Kyleo® zeigt bei einer Aufwandmenge von 5,0 l/ha eine deutlich bessere und schnellere Wirkung auf Unkräuter wie Ackerschachtelhalm (Equisetum arvense) und Ausfallraps (Brassica napus) sowie Gemeine Quecke (Agropyron repens) gegenüber Tankmischungen aus Produkten, die die Einzelwirkstoffe enthalten, sowie dem Glyphosat-Referenzprodukt (RP; 450g/L SL) 450er Glyphosat (SL). Wie ist das erklärbar? Die Antwort liegt in einer einzigartigen neuen Formulierungstechnologie, die erstmals 2,4-D als Säure und Glyphosat als Monoisopropylamine (MIPA) Salz zusammen mit einem Formulierungshilfsstoff (FHS) kombiniert. Die neue Form von 2,4-D hat lipophile Eigenschaften, d.h. eine bessere Blattaufnahme sowie einen stärkeren photolytischen Abbau in den oberen Bodenschichten gegenüber glyphosathaltigen Produkten. Ferner konnte in Versuchen mit radioaktiv markierten Wirkstoffen die systemischen Eigenschaften beider Wirkstoffe gegenüber dem RP nachgewiesen werden. Die Verlagerung von 2,4-D konnte 48 Stunden nach Behandlung in den Wurzelbereich der Pflanzen gezeigt werden. Eine 98 %-ige Glyphosat-Aufnahme in Raps und Quecke wurde beobachtet, die 10 % (Raps) bzw. 25 % (Quecke) höher lag als beim RP. Diese stärkere Aufnahme der Wirkstoffe zeichnet sich in einer schnelleren Wirkung – stärkere, sichtbare Symptome nach 24 h (Raps) und 96 h (Quecke) – gegenüber dem RP aus. Die Regenfestigkeit von Kyleo® wurde im Gewächshaus (GH) mit Raps getestet. Zur Vergleichbarkeit der Prüfmittel wurde mit einer einheitlichen Glyphosatmenge von 360 g/ha und einem simulierten Niederschlag von 10 l/m² gearbeitet. Bei einer Beregnung 1 hpt konnte eine um 24 % bessere Wirkung im Vergleich zum RP nachgewiesen werden. Wohingegen bei einer Regensimulation nach 6 hpt eine um 4 % bessere Wirkung zu verzeichnen war. In GH-Versuchen mit Weizen (Triticum aestivum) und einer identischen Glyphosataufwandmenge von 290 g/ha zeigten sich bei Regensimulation 1 hpt und 6 hpt Wirkungsunterschiede von 23 % und 22 % in Bezug zum RP. Die hier dargestellten Ergebnisse belegen eine systemische Wirkungsweise, eine gute Regenfestigkeit und eine schnelle Wirkung von Kyleo®.Stichwörter: Nicht selektives, systemisches Herbizid, Glyphosat, 2,4-D, Regenfestigkeit, Wirkstoffaufnahme, WirkstoffverteilungKyleo ® - mode of action under examinationAbstractKyleo® with two known active substances (ai) is an innovative, modern herbicide for resistance management. Kyleo® contains 160 g/L 2,4-D and 240 g/L glyphosate. With an application rate of 5,0 L/ha, it shows a far better, faster effect on weeds such as field horsetail (Equisetum arvense), volunteer oilseed rape (Brassica napus) and couch grass (Agropyron repens) compared to a tank mix or the reference products (RP). This is explained by an unique new formulation technology that for the first time combines 2,4-D as acid and glyphosate as MIPA salt together with FHS. The new form of 2,4-D is lipophilic with better leaf absorption and greater photolytic degradation in the upper layers of soil. Tests with radioactive marked substances have verified the systemic properties of both ai compared to RP. The displacement of 2,4-D into the plant roots was demonstrated 48 h after application (hpt). 98% glyphosate absorption was observed in rape and couch grass – 10% (rape) respectively 25% (couch grass) greater than with RP. Higher absorption of the ai is characterised by a swifter effect, with stronger, visible symptoms after 24 h in rape and 96 h in couch grass. The rainfastness of Kyleo® was tested in greenhouse (GH) trials with rape. Comparability of the test objects was simulated with a uniform glyphosate quantity of 360 g/ha and 10 L/m² simulated precipitation. 24% improved effect compared to RP was verified for 1 hpt rainfall, while 4% improved effect was recorded for rain simulation after 6 hpt. GH trials with wheat and a comparable glyphosate application quantity of 290 g/ha revealed differences of 23% and 22% compared to RP for rain simulation of 1 hpt and 6 hpt. Kyleo® stands out with a swift effect and better rainfastness. The results presented here prove a systemic mode of action, good rainfastness and swift effect of Kyleo.Keywords: Non selective, systemic herbicid, glyphosate, 2,4-D, rainfastness, translocation of active ingredient, uptake of active ingredien

X-ray structure of the quinoprotein ethanol dehydrogenase from \u3ci\u3ePseudomonas aeruginosa\u3c/i\u3e: basis of substrate specificity

The homodimeric enzyme form of quinoprotein ethanol dehydrogenase from Pseudomonas aeruginosa ATCC 17933 crystallizes readily with the space group R3. The X-ray structure was solved at 2.6 Å resolution by molecular replacement. Aside from differences in some loops, the folding of the enzyme is very similar to the large subunit of the quinoprotein methanol dehydrogenases from Methylobacterium extorquens or Methylophilus W3A1. Eight W-shaped β-sheet motifs are arranged circularly in a propeller-like fashion forming a disk-shaped superbarrel. No electron density for a small subunit like that in methanol dehydrogenase could be found. The prosthetic group is located in the centre of the superbarrel and is coordinated to a calcium ion. Most amino acid residues found in close contact with the prosthetic group pyrroloquinoline quinone and the Ca2+ are conserved between the quinoprotein ethanol dehydrogenase structure and that of the methanol dehydrogenases. The main differences in the active-site region are a bulky tryptophan residue in the active-site cavity of methanol dehydrogenase, which is replaced by a phenylalanine and a leucine side-chain in the ethanol dehydrogenase structure and a leucine residue right above the pyrrolquinoline quinone group in methanol dehydrogenase which is replaced by a tryptophan side-chain. Both amino acid exchanges appear to have an important influence, causing different substrate specificities of these otherwise very similar enzymes. In addition to the Ca2+ in the active-site cavity found also in methanol dehydrogenase, ethanol dehydrogenase contains a second Ca2+-binding site at the N terminus, which contributes to the stability of the native enzyme

Direct collocation methods for trajectory optimization in constrained robotic systems

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Direct collocation methods are powerful tools to solve trajectory optimization problems in robotics. While their resulting trajectories tend to be dynamically accurate, they may also present large kinematic errors in the case of constrained mechanical systems, i.e., those whose state coordinates are subject to holonomic or nonholonomic constraints, such as loop-closure or rolling-contact constraints. These constraints confine the robot trajectories to an implicitly-defined manifold, which complicates the computation of accurate solutions. Discretization errors inherent to the transcription of the problem easily make the trajectories drift away from this manifold, which results in physically inconsistent motions that are difficult to track with a controller. This article reviews existing methods to deal with this problem and proposes new ones to overcome their limitations. Current approaches either disregard the kinematic constraints (which leads to drift accumulation) or modify the system dynamics to keep the trajectory close to the manifold (which adds artificial forces or energy dissipation to the system). The methods we propose, in contrast, achieve full drift elimination on the discrete trajectory, or even along the continuous one, without artificial modifications of the system dynamics. We illustrate and compare the methods using various examples of different complexity.This work was supported in part by the Spanish Ministry of Science, Innovation, and Universities under Project DPI2017-88282-P and Project PID2020-117509GBI00/AEI/10.13039/50110001103 and in part by the German Federal Ministry for Economic Affairs and Energy (BMWi) via DyConPV (0324166B)Peer ReviewedPostprint (author's final draft

Back-arc extension in the Andaman Sea: Tectonic and magmatic processes imaged by high-precision teleseismic double-difference earthquake relocation

The geometry, kinematics, and mode of back-arc extension along the Andaman Sea plate boundary are refined using a new set of significantly improved hypocenters, global centroid moment tensor (CMT) solutions, and high-resolution bathymetry. By applying cross-correlation and double-difference (DD) algorithms to regional and teleseismic waveforms and arrival times from International Seismological Centre and National Earthquake Information Center bulletins (1964–2009), we resolve the fine-scale structure and spatiotemporal behavior of active faults in the Andaman Sea. The new data reveal that back-arc extension is primarily accommodated at the Andaman Back-Arc Spreading Center (ABSC) at ~10°, which hosted three major earthquake swarms in 1984, 2006, and 2009. Short-term spreading rates estimated from extensional moment tensors account for less than 10% of the long-term 3.0–3.8 cm/yr spreading rate, indicating that spreading by intrusion and the formation of new crust make up for the difference. A spatiotemporal analysis of the swarms and Coulomb-stress modeling show that dike intrusions are the primary driver for brittle failure in the ABSC. While spreading direction is close to ridge normal, it is oblique to the adjacent transforms. The resulting component of E-W extension across the transforms is expressed by deep basins on either side of the rift and a change to extensional faulting along the West Andaman fault system after the Mw = 9.2 Sumatra-Andaman earthquake of 2004. A possible skew in slip vectors of earthquakes in the eastern part of the ABSC indicates an en-echelon arrangement of extensional structures, suggesting that the present segment geometry is not in equilibrium with current plate-motion demands, and thus the ridge experiences ongoing re-adjustment