Browsing by Author "Drahos, Bradley"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Grasp data and analysis tools for Tissue Mechanical Response in Porcine Models from in vivo to ex vivo Conditions
    (2022-04-27) Malik, Faizan; Drahos, Bradley; Kowalewski, Timothy; malik036@umn.edu; Malik, Faizan
    Grasp Data collected from various porcine tissues in different tissue states (in vivo, postmortem, ex-vivo, post-refrigeration, and post-thaw). The raw grasps have been filtered (excluding bad grasps, retest sites), segmented to the first grasp: data narrowed to timestamps corresponding to the start and end of the first grasp at each tissue testing site. Grasp curves were generated with the force (x-axis) and displacement (y-axis) data, and curve-fitting was applied to generate an alpha and beta value for each grasp. The curve-fit values were used to obtain stiffness values for each grasp, and ANOVA analysis was performed on the derived stiffness values to compare sets of grasps. All analysis was done using MATLAB, and included is the ".mat" file which contains all grasp data used for analysis, as well as the MATLAB scripts used for curve-fitting and ANOVA analysis. This data is used in a PLOS One Journal submission.
  • Thumbnail Image
    Item
    Multi-city study of an engineering and outreach program to increase driver yielding at signalized and unsignalized crosswalks
    (Minnesota Department of Transportation, 2023-03) Morris, Nichole L.; Craig, Curtis M.; Drahos, Bradley; Tian, Disi; Van Houten, Ron; Mabry, Marshall; Kessler, William
    Pedestrian deaths are at a 30-year high nationally, accounting for 16% of total deaths in 2018 and far exceeding the previous decade of 12%, a trend mirrored in Minnesota. Previous research found an increase in local and citywide yielding at unsignalized crosswalks following an engineering and high-visibility enforcement program in Saint Paul, Minnesota. This study examined a modified engineering-focused (i.e., without enforcement) program expanded to both unsignalized and signalized intersections across the Twin Cities. The six-month study found modest improvements in yielding from baseline to treatment end (48.1% to 65.5% in Saint Paul and 19.8% to 38.8% in Minneapolis) at unsignalized engineering treatment sites but no improvements at generalization sites. No significant improvements in left- or right-turning yielding by drivers in Saint Paul were found at treated signalized intersections, but given that yielding was significantly worse at generalization sites over time, there may be some evidence that treatments mitigated performance declines among Saint Paul drivers during the study period. Yielding improvements at signalized treatment sites were more pronounced for only right-turning drivers in Minneapolis, but generalization sites showed no improvement or even worsened over time. Overall, study results suggested no shift in driving culture in either city, as found with the previous study using police enforcement, but found some evidence of local, site-specific changes in driver yielding behavior at treatment locations.