1,218 research outputs found
Learn to Bet: Using Reinforcement Learning to Improve Vehicle Bids in Auction-Based Smart Intersections
With the advent of IoT, cities will soon be populated by autonomous vehicles and managed by intelligent systems capable of actively interacting with city infrastructures and vehicles. In this work, we propose a model based on reinforcement learning that teaches to autonomous connected vehicles how to save resources while navigating in such an environment. In particular, we focus on budget savings in the context of auction-based intersection management systems. We trained several models with Deep Q-learning by varying traffic conditions to find the most performance-effective variant in terms of the trade-off between saved currency and trip times. Afterward, we compared the performance of our model with previously proposed and random strategies, even under adverse traffic conditions. Our model appears to be robust and manages to save a considerable amount of currency without significantly increasing the waiting time in traffic. For example, the learner bidder saves at least 20% of its budget with heavy traffic conditions and up to 74% in lighter traffic with respect to a standard bidder, and around three times the saving of a random bidder. The results and discussion suggest practical adoption of the proposal in a foreseen future real-life scenario
Insights on the origin of vitrified rocks from serravuda, acri (Italy): Rock fulgurite or anthropogenic activity?
In this study, twenty five partially vitrified rocks and four samples of vitrified rocks collected on the top hill called Serravuda (Acri, Calabria, Italy) are analyzed. The goal is to shed light on the origin of these enigmatic vitrified materials. The analyzed vitrified rocks are a breccia of cemented rock fragments (gneiss, granitoid, and amphibolite fragments) which extends for more than 10 m, forming a continuous mass along the northern and north-west border of the flat top hill. Surrounded by the vitrified accumulation, exposed Paleozoic granitoid substrate rocks show limited melting or heat-alteration processes. By mapping minerals embedded in the glass matrix via X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM), an interpretation of source rock material, reactions, and thermometric indications to form vitrified materials on the top hill of Serravuda, Acri (Italy), is provided. The mineralogical composition of heated or partially vitrified samples is heterogeneous owing to the effects of heating events, but it mostly recalls the parent rock composition (gneiss, granitoid, and amphibolite). The presence of quartz, cristobalite, tridymite, mullite, plagioclase, hercynite, cordierite, and olivine in Serravuda partially vitrified rocks and glasses suggests that samples were subjected to pyrometamorphism and the temperature range at which the glass formed was about 1000–1100◦C in the presence of hydrous gas, burning organic material (e.g., wood), and assuming thermodynamic equilibrium. Lithologies of the heated or partially vitrified rock fragments are a mixture of parent rocks not outcropping on the top of the hill such as gneiss and amphibolite. Data suggest that Serravuda vitrified rocks are most likely the result of anthropic activities and could represent remnants of vitrified fort walls. The mineral assemblage of partially vitrified rocks and glasses suggests that the fort walls were made of slabs derived from the local metamorphic rocks with the addition of Serravuda substrate Paleozoic granitoid rocks to improve the strength and insulation of the fort walls
The Garisenda Tower in Bologna: Effects of degradation of selenite basement on its static behaviour
The Garisenda tower in Bologna, a 48 m tall structure with a square base of 7.45 meters per side, is characterized by an overall out of plumb of 3.32m in the South-East direction. Its construction dates back to the XI century and, due to its impressive leaning, in 1350–1353 the original height of 60m was reduced to the 48m of the present day (Cavani 1903; Giordano 2000). The tower can be seen as partitioned in a lower portion, with walls composed by two external leaves of selenite stones filled with rubble conglomerate, and an upper portion where the external leaves are made of masonry bricks. Recent investigations have proved that selenite blocks of the basement have been altered as a result of (a) exposition to high temperatures during important fires, that took place at the end of XIV and XVII centuries, and possibly because of the presence of forges (that were demolished at the end of the XIX centuries) and (b) high level of humidity in the inner lower part of the tower. This process has produced a gradual local disintegration of the selenite stones, leading in some case to a reduction of the original 50 to 60 cm thickness by an amount of about 20 cm. The contribution submitted to this conference is aimed at clarifying this important aspect, linked to the ageing and damage of structural stones and the related consequences in terms of stress distribution and concentrations that could induce fracture propagation and sudden collapse of the tower basement
Complete Genome Sequence of Bifidobacterium longum W11 (LMG P-21586), Used as a Probiotic Strain
We report the complete genome sequence of Bifidobacterium longum W11 (LMG P-21586) isolated from the intestinal microbiota of a healthy man. The analysis of the sequence may provide insights into the microbiological characteristics and the functional activity of this probiotic strain
Photonic Bloch oscillations in laterally confined Bragg mirrors
We show that the photons in laterally confined Bragg mirrors may experience Bloch oscillations similar to those of electrons in semiconductor superlattices subjected to electric fields. An effective electric field is produced in the photonic case by variation of the lateral size of the structure as one moves along the structure axis. The temporal behavior of a short pulse of light oscillating within a miniband of such an optical superlattice made from the porous silicon has been modeled by a proper scattering-state simulation scheme
Cellular Automaton Study of Time-Dynamics of Avalanche Breakdown in IMPATT Diodes
Employing a recently developed efficient cellular automaton technique for solving
Boltzmann's transport equation for realistic devices, we present a detailed study of the
carrier dynamics in GaAs avalanche p-i-n (IMPATT) diodes. We find that the impact
ionization in reverse bias p-i-n diodes with ultrathin (less than 50 nm) intrinsic regions is
triggered by Zener tunneling rather than by thermal generation. The impact generation
of hot carriers occurs mainly in the low-field junction regions rather than in the high
field intrinsic zone. The calculations predict significantly more minority carriers on the
n-side than on the p-side
Assessing the Genomic Variability of Gardnerella vaginalis through Comparative Genomic Analyses: Evolutionary and Ecological Implications
Gardnerella vaginalis is described as a common anaerobic vaginal bacterium whose presence may correlate with vaginal dysbiotic conditions. In the current study, we performed phylogenomic analyses of 72 G. vaginalis genome sequences, revealing noteworthy genome differences underlying a polyphyletic organization of this taxon. Particularly, the genomic survey revealed that this species may actually include nine distinct genotypes (GGtype1 to GGtype9). Furthermore, the observed link between sialidase and phylogenomic grouping provided clues of a connection between virulence potential and the evolutionary history of this microbial taxon. Specifically, based on the outcomes of these in silico analyses, GGtype3, GGtype7, GGtype8, and GGtype9 appear to have virulence potential since they exhibited the sialidase gene in their genomes. Notably, the analysis of 34 publicly available vaginal metagenomic samples allowed us to trace the distribution of the nine G. vaginalis genotypes identified in this study among the human population, highlighting how differences in genetic makeup could be related to specific ecological properties. Furthermore, comparative genomic analyses provided details about the G. vaginalis pan- and core genome contents, including putative genetic elements involved in the adaptation to the ecological niche as well as many putative virulence factors. Among these putative virulence factors, particularly noteworthy genes identified were the gene encoding cholesterol dependent cytolysin (CDC) toxin vaginolysin and genes related to microbial biofilm formation, iron uptake, adhesion to the vaginal epithelium, as well as macrolide antibiotic resistance. IMPORTANCE The identification of nine different genotypes among members of G. vaginalis allowed us to distinguish an uneven distribution of virulence-associated genetic traits within this taxon and thus suggest the potential occurrence of putative pathogen and commensal G. vaginalis strains. These findings, coupled with metagenomics microbial profiling of human vaginal microbiota, permitted us to get insights into the distribution of the genotypes among the human population, highlighting the presence of different structural communities in terms of G. vaginalis genotypes
- …