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Item Sensor fusion to detect scale and direction of gravity in monocular SLAM systems(2017) Tucker, Seth C.; El-Sharkawy, Mohamed A.Monocular simultaneous localization and mapping (SLAM) is an important technique that enables very inexpensive environment mapping and pose estimation in small systems such as smart phones and unmanned aerial vehicles. However, the information generated by monocular SLAM is in an arbitrary and unobservable scale, leading to drift and making it difficult to use with other sources of odometry for control or navigation. To correct this, the odometry needs to be aligned with metric scale odometry from another device, or else scale must be recovered from known features in the environment. Typically known environmental features are not available, and for systems such as cellphones or unmanned aerial vehicles (UAV), which may experience sustained, small scale, irregular motion, an IMU is often the only practical option. Because accelerometers measure acceleration and gravity, an inertial measurement unit (IMU) must filter out gravity and track orientation with complex algorithms in order to provide a linear acceleration measurement that can be used to recover SLAM scale. In this thesis, an alternative method will be proposed, which detects and removes gravity from the accelerometer measurement by using the unscaled direction of acceleration derived from the SLAM odometry.Item SymTrak-8 as a Brief Measure for Assessing Symptoms in Older Adults(Springer, 2021) Monahan, Patrick O.; Kroenke, Kurt; Stump, Timothy E.; Medicine, School of MedicineBackground: Patient- and caregiver-reported 23-item SymTrak scales were validated for monitoring clinically actionable symptoms and impairments associated with multiple chronic conditions (MCCs) in older adults. Items capture physical and emotional symptoms and impairments in physical and cognitive functioning. An abbreviated SymTrak is desirable when response burden is a concern. Objective: Develop and validate the 8-item SymTrak. Design and participants: Secondary analysis of SymTrak validation study; 600 participants (200 patient-caregiver dyads; 200 patients without an identified caregiver). Main measures: Demographic questions, SymTrak, and Health Utility Index Mark 3 (HUI3). Key results: SymTrak-8 demonstrated good fit to a one-factor model using confirmatory factor analysis (CFA). Concurrent criterion validity was supported by high standardized linear regression coefficients (STB) between baseline SymTrak-8 total score (independent variable) and baseline HUI3 preference-based overall HRQOL utility score (dependent variable; 0 = death, 1 = perfect health), after adjusting for demographics, comorbid conditions, and medications, with strength comparable to SymTrak-23 (STB = - 0.81 and - 0.84, respectively, for SymTrak-8 and SymTrak-23, when patient-reported; and - 0.60 and - 0.62, respectively, when caregiver-reported). Coefficient alpha (0.74; 0.76) and 24-h test-retest reliability (0.83; 0.87) were high for SymTrak-8 for patients and caregivers, respectively. The convergent correlation between brief and parent SymTrak scales was high (0.94). SymTrak-8 demonstrated approximate normality and a linear relationship with SymTrak-23 and HUI3. Importantly, a 3-month change in SymTrak-8 was sensitive to detecting the criterion (3-month reliable change categories; improved, stable, declined in HUI3 overall utility), with results comparable to SymTrak-23. Conclusions: SymTrak-8 total score demonstrates internal reliably, test-retest reliability, criterion validity, and sensitivity to change that are comparable to SymTrak-23. Thus, patient- or caregiver-reported SymTrak-8 is a viable option for identifying and monitoring the aggregate effect of symptoms and functional impairments in patients with multimorbidity when response burden is a concern.Item VIBe Scale: Validation of the Intraoperative Bleeding Severity Scale by Spine Surgeons(International Society for the Advancement of Spine Surgery (ISASS), 2022) Sciubba, Daniel M.; Khanna, Nitin; Pennington, Zach; Singh, Rahul K.; Orthopaedic Surgery, School of MedicineBackground: The Validated Intraoperative Bleeding Scale (VIBe Scale) was initially validated with surgeons who operate on cardiothoracic, abdominal, and pelvic cavities and fulfilled criteria for a clinician-reported scale. However, there is a need for a tool to aid in intraoperative blood management during spine surgeries. The purpose of the present study was to establish the reliability and consistency of the VIBe Scale as a tool for spine surgeons to assess intraoperative bleeding. Methods: Orthopedic (n = 16) and neurological (n = 9) spine surgeons scored videos depicting surgical bleeding and assessed the VIBe Scale's relevance and clarity. Inter- and intraobserver agreement (Kendall's W) were calculated for all surgeons and pooled with responses from the original study to establish agreement across specialties. Results: All of the spine surgeons indicated that the scale was clinically relevant for evaluating hemostasis and could be implemented in a clinical study. Twenty-two spine surgeons (88%) reported that the scale represents the range of bleeding site sizes and severities expected in their practice. Twenty-four spine surgeons (96%) indicated that the scale would be useful in communicating bleeding severity with other members of the surgical team. Interobserver agreement was acceptable (0.79) for orthopedic specialists, appreciable (0.88) for neurological specialists, and appreciable (0.88) for the combined specialists. Intraobserver agreement was excellent for orthopedic (0.91) and neurological (0.91) spine surgeons and excellent (0.96) for the combined specialists. Conclusions: The results highlight the reliability of the VIBe Scale and potential utility for quantifying intraoperative blood loss in spine surgery. Clinical relevance: The VIBe Scale may be useful for evaluating the efficacy of untested intraoperative hemostatic agents and for comparing the relative efficacy of 2 or more analogous agents. It may also prove useful for intraoperative staff by quantifying ongoing intraoperative blood loss and correlating losses with the potential transfusion and intraoperative hemostatic agent requirements.