33 research outputs found
Analysis of hybrid systems using HySAT
In this paper we describe the complete workflow of analyzing the dynamic behavior of safety-critical embedded systems with HySAT. HySAT is an arithmetic constraint solver with a tightly integrated bounded model checker for hybrid discrete-continuous systems which — in contrast to many other solvers — is not confined to linear arithmetic, but can also deal with nonlinear constraints involving transcendental functions. Based on a controller for train separation implementing a “moving block ” interlocking scheme in the forthcoming European Train Control System Level 3, we exemplify the usage of the tool over the whole cycle from encoding a hybrid system to interpreting the results
High vulnerability of juvenile Nathusius' pipistrelle bats (Pipistrellus nathusii) at wind turbines
Large numbers of bats are killed by wind turbines globally, yet the specific demographic consequences of wind turbine mortality are still unclear. In this study, we compared characteristics of Nathusius' pipistrelles (Pipistrellus nathusii) killed at wind turbines (N = 119) to those observed within the live population (N = 524) during the summer migration period in Germany. We used generalized linear mixed-effects modeling to identify demographic groups most vulnerable to wind turbine mortality, including sex (female or male), age (adult or juvenile), and geographic origin (regional or long-distance migrant; depicted by fur stable hydrogen isotope ratios). Juveniles contributed with a higher proportion of carcasses at wind turbines than expected given their frequency in the live population suggesting that juvenile bats may be particularly vulnerable to wind turbine mortality. This effect varied with wind turbine density. Specifically, at low wind turbine densities, representing mostly inland areas with water bodies and forests where Nathusius' pipistrelles breed, juveniles were found more often dead beneath turbines than expected based on their abundance in the live population. At high wind turbine densities, representing mostly coastal areas where Nathusius' pipistrelles migrate, adults and juveniles were equally vulnerable. We found no evidence of increased vulnerability to wind turbines in either sex, yet we observed a higher proportion of females than males among both carcasses and the live population, which may reflect a female bias in the live population most likely caused by females migrating from their northeastern breeding areas migrating into Germany. A high mortality of females is conservation concern for this migratory bat species because it affects the annual reproduction rate of populations. A distant origin did not influence the likelihood of getting killed at wind turbines. A disproportionately high vulnerability of juveniles to wind turbine mortality may reduce juvenile recruitment, which may limit the resilience of Nathusius' pipistrelles to environmental stressors such as climate change or habitat loss. Schemes to mitigate wind turbine mortality, such as elevated cut-in speeds, should be implemented throughout Europe to prevent population declines of Nathusius' pipistrelles and other migratory bats
Storage of CO2 in saline aquifers–Lessons learned from 10 years of injection into the Utsira Formation in the Sleipner area
AbstractThe ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reached the top of the Utsira Formation, but has instead migrated laterally below imperfect intra-reservoir seals. The CO2 trapping below the structural spill point in the Utsira Formation is due to local mini traps, capillary flow resistance, and the hydrodynamic drive of the injection. About 40% of the CO2 that has entered the pore systems will remain as residually trapped CO2, whereas an unknown fraction of the remaining CO2 will migrate towards the top of the reservoir
A Revised Framework for the Investigation of Expectation Update Versus Maintenance in the Context of Expectation Violations: The ViolEx 2.0 Model
Expectations are probabilistic beliefs about the future that shape and influence our
perception, affect, cognition, and behavior in many contexts. This makes expectations
a highly relevant concept across basic and applied psychological disciplines. When
expectations are confirmed or violated, individuals can respond by either updating or
maintaining their prior expectations in light of the new evidence. Moreover, proactive
and reactive behavior can change the probability with which individuals encounter
expectation confirmations or violations. The investigation of predictors and mechanisms
underlying expectation update and maintenance has been approached from many
research perspectives. However, in many instances there has been little exchange
between different research fields. To further advance research on expectations and
expectation violations, collaborative efforts across different disciplines in psychology,
cognitive (neuro)science, and other life sciences are warranted. For fostering and
facilitating such efforts, we introduce the ViolEx 2.0 model, a revised framework
for interdisciplinary research on cognitive and behavioral mechanisms of expectation
update and maintenance in the context of expectation violations. To support different
goals and stages in interdisciplinary exchange, the ViolEx 2.0 model features three
model levels with varying degrees of specificity in order to address questions about
the research synopsis, central concepts, or functional processes and relationships,
respectively. The framework can be applied to different research fields and has high
potential for guiding collaborative research efforts in expectation research
Intelligente Vernetzung zur autonomen Fräsbearbeitung von Strukturbauteilen - Ergebnisbericht des BMBF Verbundprojektes TensorMill
Digitalisierte Prozesse können zukünftig zu einer intelligenten Fertigung beitragen, um den Herausforderungen einer intelligent vernetzten, autonomen Fertigung von sicherheitsrelevanten Integralbauteilen zu begegnen. Die Herausforderungen hierbei liegen insbesondere in der Aufzeichnung und Extraktion von nutzerrelevanten Daten zur Steigerung der Produktivität bei der Fertigung von sicherheitsrelevanten Integralbauteilen für die Luft- und Raumfahrtbranche. An diesem Punkt hat das Verbundforschungsprojekt „TensorMill“ angesetzt. Ziel des Projekts war es, die Produktivität in der spanenden Fertigung sicherheitsrelevanter Integralbauteile durch die Entwicklung und den Aufbau einer intelligent, vernetzten, autonomen Fertigung zu erhöhen und die Prozesssicherheit zu verbessern. Die intelligente Fertigung soll dabei in der Lage sein, auf möglichst viele Situationen im Fertigungsprozess mit Hilfe von künstlicher Intelligenz (KI) zu reagieren. Für die Implementierung der KI-basierten Lösungen sind im Projekt fortschrittliche Methoden und Vorgehensweisen entstanden, welche es ermöglichen, die Daten von Produktionsmitteln in einer einfachen Form nutzbar zu machen, damit diese einen Mehrwert für Hersteller und Anwender bringen. Die aufbereiteten Daten dienten schließlich der Umsetzung von KI-basierten Lösungen zur prozessparallelen Qualitätsprognose und Werkzeugzustandserkennung. Darüber hinaus wurde ein entwickeltes cyber-physisches Spannsystem entwickelt, um neuartige Ansätze zur Abdrängungskompensation und Echtzeitbewertung der Prozessstabilität zu erforschen
Fc Effector Function Contributes to the Activity of Human Anti-CTLA-4 Antibodies.
With the use of a mouse model expressing human Fc-gamma receptors (FcγRs), we demonstrated that antibodies with isotypes equivalent to ipilimumab and tremelimumab mediate intra-tumoral regulatory T (Treg) cell depletion in vivo, increasing the CD8+ to Treg cell ratio and promoting tumor rejection. Antibodies with improved FcγR binding profiles drove superior anti-tumor responses and survival. In patients with advanced melanoma, response to ipilimumab was associated with the CD16a-V158F high affinity polymorphism. Such activity only appeared relevant in the context of inflamed tumors, explaining the modest response rates observed in the clinical setting. Our data suggest that the activity of anti-CTLA-4 in inflamed tumors may be improved through enhancement of FcγR binding, whereas poorly infiltrated tumors will likely require combination approaches
Entwicklung von Ersatzmodellen zur Stabilitätsanalyse von orthotrop versteiften Schalen aus kohlenstofffaserverstärkten Kunststoffen (CFK) für den Flugzeugentwurf
Die Anwendung von Ersatzmodellen zur Stabilitatsanalyse von orthotrop versteiften Schalen
aus CFK ermoglicht eine Steigerung der Effizienz im Flugzeugentwurf. Dabei ist die
Auswahl von geeigneten Parametern fur die Metamodellierung von Bedeutung. In dieser
Arbeit werden mithilfe eines Verfahrens zur Charakterisierung von Laminaten, von Sensitivitats-
und Korrelationsanalysen geeignete Parameter fur die Beschreibung von Metamodellen
zur Stabilitatsanalyse orthotrop versteifter Schalen ermittelt. Mit den ermittelten
Parametern kann ein Metamodell erstellt werden, das fur eine Vielzahl von Schalen mit
verschiedenem Lagenaufbau herangezogen werden kann
Efficient solving of large non-linear arithmetic constraint systems with complex boolean structure
In order to facilitate automated reasoning about large Boolean combinations of nonlinear arithmetic constraints involving transcendental functions, we provide a tight integration of recent SAT solving techniques with interval-based arithmetic constraint solving. Our approach deviates substantially from lazy theorem proving approaches in that it directly controls arithmetic constraint propagation from the SAT solver rather than delegating arithmetic decisions to a subordinate solver. Through this tight integration, all the algorithmic enhancements that were instrumental to the enormous performance gains recently achieved in propositional SAT solving carry over smoothly to the rich domain of non-linear arithmetic constraints. As a consequence, our approach is able to handle large constraint systems with extremely complex Boolean structure, involving Boolean combinations of multiple thousand arithmetic constraints over some thousands of variables