Analytical, Diagnostic and Therapeutic Techniques and Equipment Commons^™

An Informational Algorithm As The Basis For Perception-Action Control Of The Instantaneous Axes Of The Knee, Wangdo Kim, Margarida M. Espanha, António P. Veloso, Duarte Araújo, Filipa João, Luis Carrão, Sean S. Kohles

Mechanical and Materials Engineering Faculty Publications and Presentations

Traditional locomotion studies emphasize an optimization of the desired movement trajectories while ignoring sensory feedback. We propose an information based theory that locomotion is neither triggered nor commanded but controlled. The basis for this control is the information derived from perceiving oneself in the world. Control therefore lies in the human-environment system. In order to test this hypothesis, we derived a mathematical foundation characterizing the energy that is required to perform a rotational twist, with small amplitude, of the instantaneous axes of the knee (IAK). We have found that the joint’s perception of the ground reaction force may be replaced …

Tracking Knee Joint Functional Axes Through Tikhonov Filtering And Plűcker Coordinates, Wangdo Kim, Yoon-Hyuk Kim, António P. Veloso, Sean S. Kohles

Mechanical and Materials Engineering Faculty Publications and Presentations

Researchers have reported several compensation methods to estimate bone and joint position from a cluster of skin-mounted markers as influenced by Soft Tissue Artifacts (STA). Tikhonov Regularization Filtering (TRF) as a means to estimate Instantaneous Screw Axes (ISA) was introduced here as a means to reduce the displacement of a rigid body to its simplest geometric form. Recent studies have suggested that the ISA of the knee, i.e., Knee Functional Axes (KFA), might be closely connected to the estimation of constraint forces such as those due to medial and lateral connective tissues. The estimations of ISAs were known to be …

Potential For False Positive Hiv Test Results With The Serial Rapid Hiv Testing Algorithm, Steven Baveewo, Moses R. Kamya, Harriet Mayanja-Kizza, Robin Fatch, David Bangsberg, Thomas J. Coates, Judith A. Hahn, Rhoda K. Wanyenze

OHSU-PSU School of Public Health Faculty Publications and Presentations

Background: Rapid HIV tests provide same-day results and are widely used in HIV testing programs in areas with limited personnel and laboratory infrastructure. The Uganda Ministry of Health currently recommends the serial rapid testing algorithm with Determine, STAT-PAK, and Uni-Gold for diagnosis of HIV infection. Using this algorithm, individuals who test positive on Determine, negative to STAT-PAK and positive to Uni-Gold are reported as HIV positive. We conducted further testing on this subgroup of samples using qualitative DNA PCR to assess the potential for false positive tests in this situation.

Results: Of the 3388 individuals who were tested, 984 were …

Development And Implementation Of Acoustic Feedback Control For Scanning Probe Microscopy, Rodolfo Fernandez Rodriguez

Dissertations and Theses

A remote-sensing acoustic method for implementing position control feedback in Scanning Probe Microscopy (SPM) is presented. The capabilities of this feedback control using the new Whispering Gallery Acoustic Sensing (WGAS) method is demonstrated in a Shear-force Scanning Probe Microscope that uses a sharp probe attached to a piezoelectric Quartz Tuning Fork (QTF) firmly mounted on the microscope's frame. As the QTF is electrically driven its mechanical response reaches the SPM frame which then acts as a resonant cavity producing acoustic modes measured with an acoustic sensor strategically placed on the SPM head. The novelty of the WGAS resides in using …

Segmentation Of Thermographic Images Of Hands Using A Genetic Algorithm, Payel Ghosh, Judith Gold, Melanie Mitchell

Computer Science Faculty Publications and Presentations

This paper presents a new technique for segmenting thermographic images using a genetic algorithm (GA). The individuals of the GA also known as chromosomes consist of a sequence of parameters of a level set function. Each chromosome represents a unique segmenting contour. An initial population of segmenting contours is generated based on the learned variation of the level set parameters from training images. Each segmenting contour (an individual) is evaluated for its fitness based on the texture of the region it encloses. The fittest individuals are allowed to propagate to future generations of the GA run using selection, crossover and …

Prostate Segmentation On Pelvic Ct Images Using A Genetic Algorithm, Payel Ghosh, Melanie Mitchell

Computer Science Faculty Publications and Presentations

A genetic algorithm (GA) for automating the segmentation of the prostate on pelvic computed tomography (CT) images is presented here. The images consist of slices from three-dimensional CT scans. Segmentation is typically performed manually on these images for treatment planning by an expert physician, who uses the “learned” knowledge of organ shapes, textures and locations to draw a contour around the prostate. Using a GA brings the flexibility to incorporate new “learned” information into the segmentation process without modifying the fitness function that is used to train the GA. Currently the GA uses prior knowledge in the form of texture …

Estimation Of Subject Specific Icp Dynamic Models Using Prospective Clinical Data, Wayne W. Wakeland, Joe Fusion, B. Goldstein

Complex Systems Faculty Publications and Presentations

We used a prospective clinical trial to generate physiologic data to create subject-specific in silico (computer simulation) models of intracranial pressure dynamics in children with severe traumatic brain injury. The trial included a physiologic challenge protocol with changes in head-of-bed elevation and minute ventilation, applied over multiple iterations to three subjects. Physiologic signals (electrocardiogram, respiration, arterial blood pressure, intracranial pressure [ICP], oxygen saturation) were recorded continuously, along with clinical annotations indicating the precise timing of physiologic challenges. Several parameters within the model of ICP dynamics were estimated for each subject based on the ICP response to the challenges. Estimation was …

A Computer Model Of Intracranial Pressure Dynamics During Traumatic Brain Injury That Explicitly Models Fluid Flows And Volumes, Wayne W. Wakeland, Brahm Goldstein, Louis Macovsky, James Mcnames

Complex Systems Faculty Publications and Presentations

This report documents a computer model of intracranial pressure (ICP) dynamics that is used to evaluate clinical treatment options for elevated ICP during traumatic brain injury (TBI). The model uses fluid volumes as primary state variables and explicitly models fluid flows as well as the resistance, compliance, and pressure associated with each of the compartments (arteries and arterioles, capillary bed, veins, venous sinus, ventricles, and brain parenchyma). The model has been tested to assure that it reproduces a correct physiologic response to intra-and extra-parenchymal hemorrhage and edema, and to therapies directed at reducing ICP such as cerebral spinal fluid drainage, …

Investigation Of Blood Pressure Measurement Using A Hydraulic Occlusive Cuff, Kusha R. Bhattarai

Dissertations and Theses

This thesis presents an improved oscillotonometric system for the measurement of human blood pressure. The study included:

1. The design of a hydraulic occlusive cuff,

2. The investigation of the wave forms taken from the blood pressure measurements, and

3. The design of a mechanism for the simulation of human blood pressure pulse.

In this study, an experimental system consisting of a rigid shell occlusive cuff, a constant volume displacement pump, a transducer, and a chart recorder was designed and used for data collection.

Psychodrama And The Terminal Patient : Concepts And Application, Marilyn Jacobs Bohan

Dissertations and Theses

This study examines the concepts of psychodrama and dying, death and bereavement that effectively meet individual needs for working through grief. It is the premise of this thesis that the working through grief to foster acceptance, self-worth and dignity, in the final st.age of life, is facilitated by psychodramatic methods of "acting through" the problems of the situation.