Browsing by Subject "Calibration"
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Item Adaptation of the 2002 Guide for the Design of Minnesota Low-Volume Portland Cement Concrete Pavements(Minnesota Department of Transportation, Research Services Section, 2007-06) Yut, Iliya; Husein, Shariq; Turgeon, Carly; Khazanovich, LevA new Mechanistic-Empirical Pavement Design Guide (MEPDG), also known as the 2002 Design Guide, was recently proposed in the United States. The development of such a procedure was conducted by the National Cooperative Highway Research Program (NCHRP) under sponsorship by the AASHTO. The Design Guide is a significant innovation in the way pavement design is performed. A comprehensive evaluation of the MEPDG performance predictions was conducted. It was found that the faulting model produced acceptable predictions, while the cracking model had to be adjusted. The cracking model was re-calibrated using the design and performance data for 65 pavement sections located in Minnesota, Iowa, Wisconsin, and Illinois. A prototype of the catalog of recommended design features for Minnesota low volume PCC pavements was developed using the MEPDG version 0.910. The catalog offers a variety of feasible design alternatives (PCC and base thickness, joint spacing and PCC slab width, edge support type, and dowel diameter) for a given combination of site conditions (traffic, location, and subgrade type). It is recognized, however, that version 0.910 is not the final version of the MEPDG. Therefore, the catalog should be updated after the MEPDG software is finalized.Item Application of the Soil and Water Assessment Tool (SWAT) to the Willow River Watershed, St. Croix County, Wisconsin.(2010-12) Murphy, Marylee SmithIdentifying critical source areas of sediment and phosphorus nonpoint pollutant loads under alternative land use scenarios is aided by the use of hydrologic models. We applied the Soil and Water Assessment Tool (SWAT) to the Willow River watershed in St. Croix County, Wisconsin, to examine the effects of possible future scenarios and best management practices. The model was calibrated and validated to water year (WY) 1999 and WY2006 datasets, respectively, with land use configured for each year. The model performed well in calibration, but could not simulate conditions outside of the calibration conditions in the validation dataset. Sediment and phosphorus trapping was influenced by trapping between the landscape source and the watershed outlet in closed-drainage lakes, flow-through wetlands, and on-stream reservoirs. The relative contributions of pollutants were related to the landscape position of the source area and the number and trapping efficiency of the intermediate traps in the flow path. We simulated best management practices including lowered soil-test phosphorus, increased conservation tillage, lowered cattle dietary phosphorus, and changed agricultural crop rotations. Simulations demonstrated that conversion to mulch tillage and no-till from conventional tillage could reduce sediment yield on the converted lands by 3% to 27% and phosphorus yield by 5% to 21%. For the current mix of agricultural land management in the Willow Watershed, converting all cropland to mulch tillage would reduce watershed export of phosphorus by 1% and sediment export by 1%. Converting all of the agricultural land to no-till produced a modeled decrease in watershed export of sediment of 2% and a decrease in phosphorus of 7%. Simulations also demonstrated a 22% reduction watershed phosphorus export by reducing average agricultural soil-test phosphorus to 20 ppm. Converting all farm land from a mixture of cash grain rotations to a dairy rotation that included two years of corn and three years of alfalfa caused a modeled reduction in watershed phosphorus export of 15% and a modeled reduction in sediment export of iii 5%. Continued conversion of agricultural land to rural residential land uses produced lower modeled loads of watershed sediment export up to 13% and phosphorus export up to 27% depending on the area developed and the average lot size. Changes in point source phosphorus because of better wastewater treatment caused a decrease in modeled phosphorus delivery of 13% between the calibration and validation time periods. Alternative climate scenarios were also simulated, showing that evapotranspiration was the driver of the altered hydrologic cycle, and thus the driver of reduced sediment and phosphorus export.Item Calibration and component placement in structured light systems for 3D reconstruction tasks.(2009-10) Bird, Nathaniel DavisThis thesis examines the amount of detail in 3D scene reconstruction that can be extracted using structured-light camera and projector based systems. Structured light systems are similar to multi-camera stereoscopic systems, except that a projector is use in place of at least one camera. This aids 3D scene reconstruction by greatly simplifying the correspondence problem, i.e., identifying the same world point in multiple images. The motivation for this work comes from problems involved with the helical tomotherapy device in use at the University of Minnesota. This device performs conformal radiation therapy, delivering high radiation dosage to certain patient body areas, but lower dosage elsewhere. The device currently has no feedback as to the patient's body positioning, and vision-based methods are promising. The tolerances for such tracking are very tight, requiring methods that maximize the quality of reconstruction through good element placement and calibration. Optimal placement of cameras and projectors for specific detection tasks is examined, and a mathematical basis for judging the quality of camera and projector placement is derived. Two competing interests are taken into account for these quality measures: the overall visibility for the volume of interest, i.e., how much of a target object is visible; and the scale of visibility for the volume of interest, i.e., how precisely points can be detected. Optimal calibration of camera and projector systems is examined as well. Calibration is important as poor calibration will ultimately lead to a poor quality reconstruction. This is a difficult problem because projected patterns do not conform to any set geometric constraints when projected onto general scenes. Such constraints are often necessary for calibration. However, it can be shown that an optimal image-based calibration can be found for camera and projector systems if there are at least two cameras whose views overlap that of the projector. The overall quality of scene reconstruction from structured light systems is a complex problem. The work in this thesis analyzes this problem from multiple directions and provides methods and solutions that can be applied to real-world systems.Item Calibration and design of the E and B EXperiment (EBEX) cryogenic receiver(2014-08) Zilic, Kyle ThomasI discuss the design, construction, and calibration of the E \& B EXperiment (EBEX), a balloon-borne telescope designed to measure the B-mode polarization anisotropy of the cosmic microwave background (CMB). EBEX observes the sky with 8 arcmin resolution in three frequency bands centered on 150, 250, and 410 GHz, with over 1,500 detectors. Polarimetry is performed through use of a continuously rotating achromatic half-wave plate with fixed wire-grid polarizer. The experiment was designed to detect the gravitational-lensed B-mode signal and detect or set an upper limit for the inflationary B-mode signal. In this thesis, I describe the design and structure of various subsystems of the EBEX receiver and predict their experimental performance. Several calibrating instrumental response experiments are described and the results reported and compared to predictions. A brief review of the 2012-2013 long duration balloon (LDB) flight from McMurdo Station, Antarctica, is provided and a summary of the receiver performance during flight characterized.Item Calibration of the E and B EXperiment (EBEX), a balloon-borne cosmic microwave background polarimeter.(2009-10) Polsgrove, Daniel EdwardWe discuss pre-flight calibration of the E and B EXperiment (EBEX), a balloon-borne telescope designed to measure the B-mode polarization anisotropy of the cosmic microwave background (CMB). EBEX will observe the sky with 8' resolution in each of three bands centered on 150, 250 and 410 GHz. Employing over 1,400 detectors and performing polarimetry through a continuously rotating half-wave plate with fixed wire-grid polarizer, we expect to detect the B-mode signal or set a new upper limit one order of magnitude below the current value. In this thesis we describe a set of ground-based experiments devised for calibrating instrumental response to incident millimeter-wave flux with varying spectral and polarization properties. We chronicle the design, construction and execution of these experiments, along with preliminary results from tests executed prior to our North American (NA) test flight which originated at the Columbia Scientific Ballooning Facility, Ft Sumner, NM in June 2009. A brief review of this inaugural flight is provided, as is a synopsis of our current plan for a comprehensive calibration strategy to be implemented in conjunction with a future long duration balloon (LDB) flight over Antarctica.Item Design, implementation, and calibration of physics Half-Wave Plate polarimetry for the E and B Experiment(2014-10) Klein, Jeffrey MichaelThe E and B Experiment (EBEX) is a balloon-borne telescope designed to measure the polarization of the Cosmic Microwave Background (CMB) and dust foregrounds at 10' scales and three frequency bands of 150 GHz, 250 GHz, and 410 GHz in order to detect or constrain B-mode polarization. Results may provide evidence to support the theory of cosmological inflation, or constrain specific models.EBEX's polarization measurement capability is implemented via continuously-rotating Half-Wave Plate (HWP) polarimetry. We discuss the design and implementation of the polarimetry hardware for the E and B Experiment (EBEX). In order to achieve low-temperature rotation of our 15 cm, 635 g achromatic HWP stack, we implement a unique application of a Superconducting Magnetic Bearing (SMB), building off an earlier prototype. We discuss design constraints, detail our implementation, and present results of tests of power dissipation, rotation speed stability, dynamic stability, and operational lifetime. We find power dissipation of 15 mW in our LDB configuration, and achieve successful operation of the system in both a 2009 test flight and a 2012 Long Duration (LDB) flight.We design and carry out calibration tests to verify our ability to measure polarized signals. We develop a data analysis pipeline to extract polarization measurements from the chopped polarized signals we use in calibration; we verify and optimize the performance of this pipeline with a simulation. We find that a thorough understanding of the time constants of EBEX's bolometric sensors is essential to measure polarization. We develop methods to measure and remove the effects of these time constants. Tests of polarization rotation across our bands verify predictions of rotation due to our achromatic HWP 5-stack. Polarized beam scans allow us to set an absolute calibration for EBEX with a standard deviation of 1.5 degrees.Item The Effect of Incorporating Active Learning In Calibration Exercises On Intra and Interrater Reliability Among Dental Hygiene Faculty(2019-09) Hotzler, BridgetABSTRACT Purpose/Objective: The purpose of this study was to investigate if incorporating active learning into calibration exercises increased the level of intra- and interrater reliability among dental hygiene faculty. Methods: The study used a two-group randomized experimental design with a convenience sample consisting of ten dental hygiene faculty members from the division of dental hygiene at the University of Minnesota (n=10). Baseline training in motivational interviewing (MI) was provided to all faculty at a day-long continuing education course. One month later, all faculty viewed three videos of students performing MI during an OSCE and graded their performance using a standardized grading rubric. The treatment group then engaged in the identical motivational interviewing OSCE required of the students. One month later, both study groups viewed the same three videos and graded the students’ MI performance using the identical standardized grading rubric. (See Appendix C). Results: The overall intra-rater reliability was calculated using Cohen’s Kappa statistic, pre-and post-intervention for both the control and treatment groups. Results revealed moderate to weak intra-rater reliability for both groups (.494). Fleiss’ kappa statistic was used to assess interrater reliability. The treatment group achieved higher levels of agreement verses the control group on six of the ten questions. Only one question (See Figure 1: R06) had perfect or near perfect agreement in both study groups. Conclusion: There was no statistically significant difference found in intra- and interrater reliability scores between the control and treatment groups following an active learning intervention. Even though statistical significance was not achieved, individual faculty data suggests active learning did have an effect on the faculty in the treatment group. Post intervention, faculty in the treatment group had greater variations in scores indicating the experience had challenged their frame of knowledge and may have become more empathetic to the challenges of motivational interviewing having conducted an MI session themselves.Item Implementation of Traffic Data Quality Verification for WIM Sites(Center for Transportation Studies University of Minnesota, 2015-05) Liao, Chen-Fu; Chatterjee, Indrajit; Davis, Gary A.Weigh-In-Motion (WIM) system tends to go out of calibration from time to time, as a result generate biased and inaccurate measurements. Several external factors such as vehicle speed, weather, pavement conditions, etc. can be attributed to such anomaly. To overcome this problem, a statistical quality control technique is warranted that would provide the WIM operator with some guidelines whenever the system tends to go out of calibration. A mixture modeling technique using Expectation Maximization (EM) algorithm was implemented to divide the Gross Vehicle Weight (GVW) measurements of vehicle class 9 into three components, (unloaded, partially loaded, and fully loaded). Cumulative Sum (CUSUM) statistical process technique was used to identify any abrupt change in mean level of GVW measurements. Special attention was given to the presence of auto-correlation in the data by fitting an auto-regressive time series model and then performing CUSUM analysis on the fitted residuals. A data analysis software tool was developed to perform EM Fitting and CUSUM analyses. The EM analysis takes monthly WIM raw data and estimates the mean and deviations of GVW of class 9 fully loaded trucks. Results of the EM analyses are stored in a file directory for CUSUM analysis. Output from the CUSUM analysis will indicate whether there is any sensor drift during the analysis period. Results from the analysis suggest that the proposed methodology is able to estimate a shift in the WIM sensor accurately and also indicate the time point when the WIM system went out-of-calibration. A data analysis software tool, WIM Data Analyst, was developed using the Microsoft Visual Studio software development package based on the Microsoft Windows .NET framework. An open source software tool called R.NET was integrated into the Microsoft .NET framework to interface with the R software which is another open source software package for statistical computing and analysis.Item Measurement of nuclear recoils in the CDMS II Dark Matter Search(2014-12) Fallows, Scott MathewThe Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS~II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for ``background-free'' operation of CDMS~II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space.These results, like any others, are subject to a variety of systematic effects that may alter their final interpretations. A primary focus of this dissertation will be difficulties in precisely calibrating the energy scale for nuclear recoil events like those from WIMPs.Nuclear recoils have suppressed ionization signals relative to electron recoils of the same recoil energy, so the response of the detectors is calibrated differently for each recoil type. The overall normalization and linearity of the energy scale for electron recoils in CDMS~II detectors is clearly established by peaks of known gamma energy in the ionization spectrum of calibration data from a $^{133}$Ba source. This electron-equivalent (keV$_mathrm{ee}$) energy scale enables calibration of the total phonon signal (keV$_mathrm{t}$) by enforcing unity yield for electron recoils, in aggregate. Subtracting an event's Luke phonon contribution from its calibrated total phonon energy (keV$_mathrm{t}$), as measured by the ionization signal, results in a valid measure of the true recoil energy (keV$_mathrm{r}$) for both electron and nuclear recoils.I discuss systematic uncertainties affecting the reconstruction of this recoil energy, the primary analysis variable, and use several methods to constrain their magnitude. I present the resulting adjusted WIMP limits and discuss their impact in the context of current and projected constraints on the parameter space for WIMP interactions.Item Modeling stochastic human-driver car following behavior in oscillatory traffic conditions(Center for Transportation Studies, University of Minnesota, 2021-08) Stern, Raphael; Shang, MingfengAccurately modeling the realistic and unstable traffic dynamics of human-driven traffic flow is crucial to being able to understand how traffic dynamics evolve, and how new agents such as autonomous vehicles might influence traffic flow stability. This work is motivated by a recent dataset that allows us to calibrate accurate models, specifically in conditions when traffic waves arise. Three microscopic car-following models are calibrated using a microscopic vehicle trajectory dataset that is collected with the intent of capturing oscillatory driving conditions. For each model, five traffic flow metrics are constructed to compare the flow-level characteristics of the simulated traffic with experimental data.Item Simplified Design Table For Minnesota Concrete Pavements(Minnesota Department of Transportation Research Services & Library, 2014-06) Tompkins, Derek; Khazanovich, LevThe project “Simplified Design Table for Minnesota Concrete Pavements” led to the creation of MnPCC-ME, a standalone 32-bit Windows executable program to replace the preexisting RigidPave. Whereas RigidPave was based upon the outdated AASHTO 1993 design procedure for rigid pavements, MnPCC-ME is based on MEPDG version 1.1, a mechanistic-empirical design procedure that accounts for the effects of traffic loading and environment. Furthermore, MnPCC-ME was localized for Minnesota pavements through: 1) the use of local climate data and weigh-in-motion traffic data; 2) the incorporation of previously conducted calibrations of the MEPDG for Minnesota pavements; and 3) the inclusion of advanced analysis features included in MnPCC-ME’s flexible design counterpart, MnPAVE. The development and source code of MnPCC-ME is detailed in this final report.Item Traffic Data Quality Verification and Sensor Calibration for Weigh-In-Motion (WIM) Systems(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2012-08) Liao, Chen-Fu; Davis, Gary A.Many state departments of transportation have been collecting various traffic data through the Automatic Traffic Recorder (ATR) and Weigh-in-Motion (WIM) systems as outlined in the Traffic Monitoring Guide (TMG) published by USDOT. A pooled fund study led by MnDOT was conducted in 2002 to determine traffic data editing procedures. It is challenging to identify potential problems associated with the collected data and ensure data quality. The WIM system itself presents difficulty in obtaining accurate data due to sensor characteristics, complex vehicle dynamics, and the pavement changes surrounding the sensor over time. To overcome these limitations, calibration procedures and other monitoring activities are essential to data reliability and accuracy. Current practice of WIM calibration procedures varies from organization to organization. This project aims to understand the characteristics of WIM measurements, identify different WIM operational modes, and develop mixture models for each operation period. Several statistical data analysis methodologies were explored to detect measurement drifts and support sensor calibration. A mixture modeling technique using Expectation Maximization (EM) algorithm and cumulative sum (CUSUM) methodologies were explored for data quality assurance. An adjusting CUSUM methodology was used to detect data anomaly. The results indicated that the adjusting CUSUM methodology was able to detect the sensor drifts. The CUSUM curves can trigger a potential drifting alert to the WIM manager. Further investigation was performed to compare the CUSUM deviation and the calibration adjustment. However, the analysis results did not indicate any relationship between the computed CUSUM deviation and the calibration adjustment.