11 research outputs found
The Kilopixel Array Pathfinder Project (KAPPa), a 16 pixel integrated heterodyne focal plane array
KAPPa (the Kilopixel Array Pathfinder Project) is developing key technologies to enable the construction of heterodyne focal plane arrays in the terahertz frequency regime with ~1000 pixels. The leap to ~1000 pixels requires solutions to several key technological problems before the construction of such a focal plane is possible. The KAPPa project will develop a small (16-pixel) 2D integrated heterodyne focal plane array for the 660 GHz atmospheric window as a technological pathfinder towards future kilopixel heterodyne focal plane arrays
Towards Autonomy and Mobility for a Tethered Robot Exploring Extremely Steep Terrain
Mobile robots are well suited to explore environments considered too costly, time consuming, and hazardous for human inspection. However, a recent push to explore increasingly extreme environments has required the development of robust mobile platforms that can navigate steep, cluttered terrain, operate for extended periods, and relay information to a remote operator. Applications of these systems include terrestrial and planetary geologic survey and infrastructure inspection, where remote observation is not a viable option. This thesis chronicles the design, development, and testing of the physical platform and autonomy functions for the Tethered Robotic eXplorer (TReX), a novel mapping robot capable of navigating near-vertical terrain while supported by an attached electromechanical tether; the tether provides continuous power and communication to and from the robot, but also constrains motion due to its finite length and susceptibility to entanglement in cluttered environments. A tethered robot can avoid entanglement by (i) mapping intermediate anchors (locations of obstacle-to-tether contacts), and (ii) autonomously retracing its outgoing path to sequentially unwrap the tether from obstacles. We approach (i) by formulating incremental and batch solutions to a new TSLAM problem using tether measurements to aid odometry and map anchors, and handle (ii) using visual route following in conjunction with autonomous tether control to manage tension and assist the robot to repeat previously driven paths on steep terrain. This work concludes with a geologic surveying mission, where TReX is teleoperated to explore and map a steep, tree-covered rock outcrop in an outdoor mine.Ph.D
3D Kinematic Passive-Steering Control with Roll Compensation for Rover Trajectory Following over Rough Terrain
Some of the most appealing areas for future planetary surface exploration lie in rough, uneven terrains, such as craters and cold traps, which are currently inaccessible by state-of-the-art robotic systems [1]. To provide modularity for access and in-situ sampling within such extreme environments, Jet Propulsion Laboratory (JPL) and California Institute of Technology have collaborated to develop the DuAxel rover system, a modular robot composed of two Axel rappelling vehicles docked to a central module into a four-wheeled configuration, suited for driving long distances due to articulated passivesteering capabilities [2]. Inspired by Carnegie Mellon’s Zoë rover [3], a 3D kinematic control strategy, leveraging a novel, DuAxel-centric model, has been developed to enable precise trajectory following over rough, flat terrain with presence of obstacles
Comorbid Dysphagia and Dyspnea in Muscle Tension Dysphonia: A Global Laryngeal Musculoskeletal Problem
Objective To characterize the associated symptoms of dysphagia and dyspnea among patients presenting with muscle tension dysphonia (MTD). Study Design Retrospective chart review performed over a 14-month period from October 2014 to December 2015. Setting Voice and swallowing center of a tertiary academic medical center. Subjects and Methods Thirty-eight patients with MTD were included for analysis. Clinical data were collected and analyzed, including perceptual voice evaluation and patient-reported outcomes measures. Results Among patients with a diagnosis of MTD, the incidence of reported dysphagia during clinical history and examination was 44.7%. Among patients with MTD, 60.5% had an EAT-10 (10-item Eating Assessment Tool) score ≥3 (ie, abnormal). Patients who reported dysphagia and/or had abnormal EAT-10 score (≥3) had significantly greater voice impairment than that of patients without dysphagia ( P = .02). Patients who reported dysphagia also had significantly higher Clinical COPD Questionnaire scores than those of patients who reported only dysphonia ( P = .002). Conclusions Patients presenting for dysphonia who are diagnosed with MTD have a high rate of comorbid dysphagia. Patients who reported dysphagia had significantly higher self-reported voice impairment and greater severity of breathing dysfunction as measured by the Clinical COPD Questionnaire. The coincidence of these symptoms in this patient cohort may suggest an underlying pathophysiology that has yet to be elucidated. Further prospective studies are needed to clarify the underlying cause of dysphagia and breathing dysfunction in the setting of MTD and to investigate diagnostic and therapeutic paradigms
The kilopixel array pathfinder project (KAPPa), a 16-pixel integrated heterodyne focal plane array — Characterization of the single pixel prototype
We report on the laboratory testing of KAPPa, a 16-pixel proof-of-concept array to enable the creation THz imaging spectrometer with -1000 pixels. Creating an array an order of magnitude larger than the existing state of the art of 64 pixels requires a simple and robust design as well as improvements to mixer selection, testing, and assembly. We present the characterization of the single pixel prototype, capable of housing an electromagnet or permanent magnet to suppress Josephson noise. We also present the current 16-pixel array design. This design continually evolves during single pixel testing
The kilopixel array pathfinder project (KAPPa), a 16-pixel integrated heterodyne focal plane array — Characterization of the single pixel prototype
We report on the laboratory testing of KAPPa, a 16-pixel proof-of-concept array to enable the creation THz imaging spectrometer with -1000 pixels. Creating an array an order of magnitude larger than the existing state of the art of 64 pixels requires a simple and robust design as well as improvements to mixer selection, testing, and assembly. We present the characterization of the single pixel prototype, capable of housing an electromagnet or permanent magnet to suppress Josephson noise. We also present the current 16-pixel array design. This design continually evolves during single pixel testing
Diagnostic Delay in HPV-Related Oropharyngeal Squamous Cell Carcinoma
Introduction Human papillomavirus-related (HPV + ) oropharyngeal squamous cell carcinoma (OPSCC) is increasing in incidence and presents diagnostic challenges given its unique clinical presentation