Minkowski decompositions for generalized associahedra of acyclic type

We give an explicit subword complex description of the generators of the type cone of the g-vector fan of a finite type cluster algebra with acyclic initial seed. This yields in particular a description of the Newton polytopes of the F-polynomials in terms of subword complexes as conjectured by S. Brodsky and the third author. We then show that the cluster complex is combinatorially isomorphic to the totally positive part of the tropicalization of the cluster variety as conjectured by D. Speyer and L. Williams.Comment: 17 pages. v2: updated and extended examples, added footnote that Theorem 1.4 also follows from [AHL20, Theorems 4.1 & 4.2

A novel learning automata game with local feedback for parallel optimization of hydropower production

Master's thesis Information- and communication technology IKT590 - University of Agder 2017Hydropower optimization for multi-reservoir systems is classi ed as a combinatorial optimization problem with large state-space that is particularly di cult to solve. There exist no golden standard when solving such problems, and many proposed algorithms are domain speci c. The literature describes several di erent techniques where linear programming approaches are extensively discussed, but tends to succumb to the curse of dimensionality problem when the state vector dimensions increase. This thesis introduces LA LCS, a novel learning automata algorithm that utilizes a parallel form of local feedback. This enables each individual automaton to receive direct feedback, resulting in faster convergence. In addition, the algorithm is implemented using a parallel architecture on a CUDA enabled GPU, along with exhaustive and random search. LA LCS has been veri ed through several scenarios. Experiments show that the algorithm is able to quickly adapt and nd optimal production strategies for problems of variable complexity. The algorithm is empirically veri ed and shown to hold great promise for solving optimization problems, including hydropower production strategies

Towards an Explanatory Design Theory for Context-Dependent Learning in Immersive Virtual Reality

Immersive virtual reality (IVR) is increasingly used for learning. However, research on specific designs for IVRs which can be used to enhance individual learning performance is still at an early stage. In this research-in-progress paper, we build upon theories on context-dependent learning to develop an explanatory design theory. We hypothesize that if the user learns in a virtual environment that represents the recall environment (environmental congruence), recall is facilitated. Additionally, if the IVR is designed with a high degree of sensory immersion, the effect of environmental congruence on learning is further increased through enhanced cognitive absorption in the technology. In contrast, cognitive absorption in the task should have a reversed effect. To test the explanatory design theory, we plan to conduct a 2 (learning environment: Room A vs. Room B) x 2 (sensory immersion: low vs. high) x 2 (recall environment: Room A vs. Room B) between-subjects laboratory experiment

Adaptive Laboratory Evolution of Antibiotic Resistance Using Different Selection Regimes Lead to Similar Phenotypes and Genotypes

Antibiotic resistance is a global threat to human health, wherefore it is crucial to study the mechanisms of antibiotic resistance as well as its emergence and dissemination. One way to analyze the acquisition of de novo mutations conferring antibiotic resistance is adaptive laboratory evolution. However, various evolution methods exist that utilize different population sizes, selection strengths, and bottlenecks. While evolution in increasing drug gradients guarantees high-level antibiotic resistance promising to identify the most potent resistance conferring mutations, other selection regimes are simpler to implement and therefore allow higher throughput. The specific regimen of adaptive evolution may have a profound impact on the adapted cell state. Indeed, substantial effects of the selection regime on the resulting geno- and phenotypes have been reported in the literature. In this study we compare the geno- and phenotypes of Escherichia coli after evolution to Amikacin, Piperacillin, and Tetracycline under four different selection regimes. Interestingly, key mutations that confer antibiotic resistance as well as phenotypic changes like collateral sensitivity and cross-resistance emerge independently of the selection regime. Yet, lineages that underwent evolution under mild selection displayed a growth advantage independently of the acquired level of antibiotic resistance compared to lineages adapted under maximal selection in a drug gradient. Our data suggests that even though different selection regimens result in subtle genotypic and phenotypic differences key adaptations appear independently of the selection regime