2,478 research outputs found
Relations Between Graphs
Given two graphs G and H, we ask under which conditions there is a relation R
that generates the edges of H given the structure of graph G. This construction
can be seen as a form of multihomomorphism. It generalizes surjective
homomorphisms of graphs and naturally leads to notions of R-retractions,
R-cores, and R-cocores of graphs. Both R-cores and R-cocores of graphs are
unique up to isomorphism and can be computed in polynomial time.Comment: accepted by Ars Mathematica Contemporane
Dichoptic vision in the absence of attention: neither fusion nor rivalry
When the two eyesâ processing streams meet in visual cortex, two things can happen: sufficiently similar monocular inputs are combined into a fused representation, whereas markedly different inputs engage in rivalry. Interestingly, the emergence of rivalry appears to require attention. Withdrawing attention causes the alternating monocular dominance that characterizes rivalry to cease, apparently allowing both monocular signals to be processed simultaneously. What happens to these signals in this case, however, remains something of a mystery; are they fused into an integrated representation? In a set of experiments, we show this not to be the case: visual aftereffects are consistent with the simultaneous yet separate presence of two segregated monocular representations, rather than a joint representation. These results provide evidence that dichoptic vision without attention prompts a third and previously unknown mode, where both eyesâ inputs receive equal processing, but escape interocular fusion
Complete Agent-driven Model-based System Testing for Autonomous Systems
In this position paper, a novel approach to testing complex autonomous
transportation systems (ATS) in the automotive, avionic, and railway domains is
described. It is intended to mitigate some of the most critical problems
regarding verification and validation (V&V) effort for ATS. V&V is known to
become infeasible for complex ATS, when using conventional methods only. The
approach advocated here uses complete testing methods on the module level,
because these establish formal proofs for the logical correctness of the
software. Having established logical correctness, system-level tests are
performed in simulated cloud environments and on the target system. To give
evidence that 'sufficiently many' system tests have been performed with the
target system, a formally justified coverage criterion is introduced. To
optimise the execution of very large system test suites, we advocate an online
testing approach where multiple tests are executed in parallel, and test steps
are identified on-the-fly. The coordination and optimisation of these
executions is achieved by an agent-based approach. Each aspect of the testing
approach advocated here is shown to either be consistent with existing
standards for development and V&V of safety-critical transportation systems, or
it is justified why it should become acceptable in future revisions of the
applicable standards.Comment: In Proceedings FMAS 2021, arXiv:2110.1152
Stress-Strain Relation in Debris Flow Analysis
In debris flow analysis, the generalized viscop1astic fluid (GVF) model can be used as the constitutive equations. When the yield stress is negligible, the shear expression in the GVF model for simple shear flow reduces to r = ”1 (du/dz)n, where r is the shear stress, ”1 is the consistency index, du/dz is the shear rate, and n is the flow behavior index. In this paper the r versus du/dz relation is studied by running experiments with 14 mm dry glass spheres in a conveyor-belt flume. A comparison of the estimated r with the measured du/dz across the flow depth indicates that ”1 is a strong function of the concentration that changes across the flow depth and thus, must be included in the analysis of the r versus du/dz relation. An analysis of experimental results indicates that a relation between r/”1 and du/dz is more meaningful; therefore, concentration data across the flow depth is needed. In this paper a viable method based on a Van Der Waals type equation of state is developed from experimental results, thereby assessing the applicability of r/”1 versus du/dz relation in debris flow analysis
Stress-Strain Relation in Debris Flow Analysis
In debris flow analysis, the generalized viscop1astic fluid (GVF) model can be used as the constitutive equations. When the yield stress is negligible, the shear expression in the GVF model for simple shear flow reduces to r = ”1 (du/dz)n, where r is the shear stress, ”1 is the consistency index, du/dz is the shear rate, and n is the flow behavior index. In this paper the r versus du/dz relation is studied by running experiments with 14 mm dry glass spheres in a conveyor-belt flume. A comparison of the estimated r with the measured du/dz across the flow depth indicates that ”1 is a strong function of the concentration that changes across the flow depth and thus, must be included in the analysis of the r versus du/dz relation. An analysis of experimental results indicates that a relation between r/”1 and du/dz is more meaningful; therefore, concentration data across the flow depth is needed. In this paper a viable method based on a Van Der Waals type equation of state is developed from experimental results, thereby assessing the applicability of r/”1 versus du/dz relation in debris flow analysis
Case report: VA-ECMO for fulminant myocarditis in an infant with acute COVID-19
Fulminant myocarditis in children was rare during the coronavirus disease 2019 pandemic, but it had the potential for high morbidity and mortality. We describe the clinical course of a previously healthy 9-month-old young male infant who rapidly deteriorated into cardiogenic shock due to coronavirus disease 2019-related fulminant myocarditis. He developed severe heart failure and multiple organ dysfunction syndrome that were treated promptly with central venoarterial extracorporeal membrane oxygenation and continuous venovenous hemofiltration. He made a good recovery without significant morbidity
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