896 research outputs found

    Mapping similarities in temporal parking occupancy behavior based on city-wide parking meter data

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    The search for a parking space is a severe and stressful problem for drivers in many cities. The provision of maps with parking space occupancy information assists drivers in avoiding the most crowded roads at certain times. Since parking occupancy reveals a repetitive pattern per day and per week, typical parking occupancy patterns can be extracted from historical data. In this paper, we analyze city-wide parking meter data from Hannover, Germany, for a full year. We describe an approach of clustering these parking meters to reduce the complexity of this parking occupancy information and to reveal areas with similar parking behavior. The parking occupancy at every parking meter is derived from a timestamp of ticket payment and the validity period of the parking tickets. The similarity of the parking meters is computed as the mean-squared deviation of the average daily patterns in parking occupancy at the parking meters. Based on this similarity measure, a hierarchical clustering is applied. The number of clusters is determined with the Davies-Bouldin Index and the Silhouette Index. Results show that, after extensive data cleansing, the clustering leads to three clusters representing typical parking occupancy day patterns. Those clusters differ mainly in the hour of the maximum occupancy. In addition, the lo-cations of parking meter clusters, computed only based on temporal similarity, also show clear spatial distinctions from other clusters

    Bio-material polylactic acid/poly(butylene adipate-co-terephthalate) blend developed for extrusion- based additive manufacturing

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    Bio-material polylactic acid and poly(butylene adipate-co-terephthalate) were blended to achieve increased ductility of the blend. Cloisite was added to improve the stiffness of the blend. The blends were made into filament suitable for extrusion-based additive manufacturing. Melt flow index of the filament and mechanical properties of the printed bars were tested. Preliminary results showed that the melt flow index increases significantly with cloisite and the modulus of polylactic acid/poly(butylene adipate-co-terephthalate) improved slightly. The notched impact strength of the blend increased with increasing content of cloisite, and it increased significantly after annealing, especially for blends without cloisite

    The transferability and design of commercial printer settings in PLA/PBAT fused filament fabrication

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    In many fused filament fabrication (FFF) processes, commercial printers are used, but rarely are printer settings transferred from one commercial printer to the other to give similar final tensile part performance. Here, we report such translation going from the Felix 3.0 to Prusa i3 MK3 printer by adjusting the flow rate and overlap of strands, utilizing an in-house developed blend of polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT). We perform a sensitivity analysis for the Prusa printer, covering variations in nozzle temperature, nozzle diameter, layer thickness, and printing speed (T-nozzle, d(nozzle), LT, and v(print)), aiming at minimizing anisotropy and improving interlayer bonding. Higher mass, larger width, and thickness are obtained with larger d(nozzle), lower v(print), higher LT, and higher T-nozzle. A higher v(print) results in less tensile strain at break, but it remains at a high strain value for samples printed with d(nozzle) equal to 0.5 mm. v(print) has no significant effect on the tensile modulus and tensile and impact strength of the samples. If LT is fixed, an increased d(nozzle) is beneficial for the tensile strength, ductility, and impact strength of the printed sample due to better bonding from a wider raster structure, while an increased LT leads to deterioration of mechanical properties. If the ratio d(nozzle)/LT is greater than 2, a good tensile performance is obtained. An improved T-nozzle leads to a sufficient flow of material, contributing to the performance of the printed device. The considerations brought forward result in a deeper understanding of the FFF process and offer guidance about parameter selection. The optimal d(nozzle)/v(print)/LT/T-nozzle combination is 0.5 mm/120 mm s(-1)/0.15 mm/230 degrees C

    Graph theoretical analysis of functional network for comprehension of sign language

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    This work was supported by grants from the National Natural Science Foundation of China (NSFC: 31571158, 31170969) and National Key Basic Research Program of China (2014CB846102), and a grant from the National Institutes of Health (R01 DC010997). We thank Yong He and Roel Willems for providing insightful comments to this study and Amie Fairs for proofreading the manuscript. No conflict of interest is declared.Peer reviewedPostprin

    Excess adenosine in murine penile erectile tissues contributes to priapism via A2B adenosine receptor signaling.

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    Priapism, abnormally prolonged penile erection in the absence of sexual excitation, is associated with ischemia-mediated erectile tissue damage and subsequent erectile dysfunction. It is common among males with sickle cell disease (SCD), and SCD transgenic mice are an accepted model of the disorder. Current strategies to manage priapism suffer from a poor fundamental understanding of the molecular mechanisms underlying the disorder. Here we report that mice lacking adenosine deaminase (ADA), an enzyme necessary for the breakdown of adenosine, displayed unexpected priapic activity. ADA enzyme therapy successfully corrected the priapic activity both in vivo and in vitro, suggesting that it was dependent on elevated adenosine levels. Further genetic and pharmacologic evidence demonstrated that A2B adenosine receptor-mediated (A2BR-mediated) cAMP and cGMP induction was required for elevated adenosine-induced prolonged penile erection. Finally, priapic activity in SCD transgenic mice was also caused by elevated adenosine levels and A2BR activation. Thus, we have shown that excessive adenosine accumulation in the penis contributes to priapism through increased A2BR signaling in both Ada -/- and SCD transgenic mice. These findings provide insight regarding the molecular basis of priapism and suggest that strategies to either reduce adenosine or block A2BR activation may prove beneficial in the treatment of this disorder
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