Quantitative assessment of human motion using video motion analysis

In the study of the dynamics and kinematics of the human body, a wide variety of technologies was developed. Photogrammetric techniques are well documented and are known to provide reliable positional data from recorded images. Often these techniques are used in conjunction with cinematography and videography for analysis of planar motion, and to a lesser degree three-dimensional motion. Cinematography has been the most widely used medium for movement analysis. Excessive operating costs and the lag time required for film development coupled with recent advances in video technology have allowed video based motion analysis systems to emerge as a cost effective method of collecting and analyzing human movement. The Anthropometric and Biomechanics Lab at Johnson Space Center utilizes the video based Ariel Performance Analysis System to develop data on shirt-sleeved and space-suited human performance in order to plan efficient on orbit intravehicular and extravehicular activities. The system is described

Quantitative assessment of human motion using video motion analysis

In the study of the dynamics and kinematics of the human body a wide variety of technologies has been developed. Photogrammetric techniques are well documented and are known to provide reliable positional data from recorded images. Often these techniques are used in conjunction with cinematography and videography for analysis of planar motion, and to a lesser degree three-dimensional motion. Cinematography has been the most widely used medium for movement analysis. Excessive operating costs and the lag time required for film development, coupled with recent advances in video technology, have allowed video based motion analysis systems to emerge as a cost effective method of collecting and analyzing human movement. The Anthropometric and Biomechanics Lab at Johnson Space Center utilizes the video based Ariel Performance Analysis System (APAS) to develop data on shirtsleeved and space-suited human performance in order to plan efficient on-orbit intravehicular and extravehicular activities. APAS is a fully integrated system of hardware and software for biomechanics and the analysis of human performance and generalized motion measurement. Major components of the complete system include the video system, the AT compatible computer, and the proprietary software

BIOMECHANICAL ANALYSIS OF THE SHOT-PUT EVENT AT THE 2004 ATHENS OLYMPIC GAMES

The purpose of this study was to analyze the best shot put performances in the Athens 2004 Olympic Games. Multiple high speed digital video cameras were placed in specific locations on the field at proper angles in order to capture the performance of the athletes in the preliminaries and finals. Two stationary cameras were placed at 45 degrees to each other. In addition 3 more cameras used by the NBC broadcasting were used to assist the other 2 cameras. Temporal and kinematics variables were calculated from the videos records and were analyzed yielding three-dimensional biomechanical results. Patterns of the segmental movements were used rather than absolute values, to assist the athletes and the coaches in the analysis of the performances. Kinematics parameters for the best 3 fina'l performers were presented in this study

Software-Enabled Smallsat Autonomy: Discussion with Examples

Smallsat missions using cooperating constellations offer significant benefits compared to traditional space missions. These benefits include lower unit costs, better robustness to failures, and the ability to collect data in a distributed fashion. Significant commercial smallsat missions are active in low Earth orbit, and spacecraft operators have expressed interest in smallsat constellations operating both at higher altitudes and in proximity operations missions. Autonomy plays a significant role in extending smallsat missions to these more challenging domains. Autonomy in a broad sense refers to a spacecraft\u27s or constellation\u27s ability to operate independently of ground systems, and affects every part of a typical mission. For example, onboard processing of data can significantly reduce the frequency and expense of communications to a terrestrial ground station link. Onboard safety and health management is critical in proximity operations with fast dynamics, or in remote operations where offboard monitoring is available infrequently. Onboard monitoring of mission objectives enables remote operations and reduces the required operator workload. Emergent Space Technologies has developed flight software products to enable future missions with greater autonomy. Navigator is a standalone application for cooperative absolute and relative navigation within a cluster of space vehicles. The Autopilot software suite enables routine orbit maintenance and satellite maneuvers to be monitored and executed onboard, increasing safety and reducing reliance on ground systems. Guardian is a suite of applications thatenable fault detection, isolation, and recovery on modules within a distributed mission. The Cirrus cloud computing framework enables distributed computing tasks within a fleet of cooperating platforms, allowing complex data processing algorithms to be executed onboard and distributed among vehicles according to their computational availability. Finally, Commander is a set of applications for autonomous execution of a planned mission on a distributed group of platforms. Critically, Commander enables autonomous coordination of the actions of Navigator, Autopilot, Guardian, and Cirrus, providing a significantly greater level of autonomy than the suites provide individually. In this paper, we describe the capabilities of the flight software and demonstrate how coordination using Commander enables desired operator missions. The following missions are considered: (1) autonomous lunar injection; (2) rendezvous and proximity operations; (3) constellation intelligence, surveillance, and reconnaissance. Discussion is informed by use case diagrams and simulation results using Emergent\u27s Ascent simulation environment

Reach performance while wearing the Space Shuttle launch and entry suit during exposure to launch accelerations

Crewmen aboard the Space Shuttle are subjected to accelerations during ascent (the powered flight phase of launch) which range up to +3 G(sub x). Despite having 33 missions and nine years experience, not to mention all the time spent in development prior to the first flight, no truly quantitative reach study wearing actual crew equipment, using actual Shuttle seats and restraints has ever been done. What little information exists on reach performance while under acceleration has been derived primarily from subjective comments gathered retrospectively from Shuttle flight crews during their post mission debrief. This lack of reach performance data has resulted in uncertainty regarding emergency procedures that can realistically be performed during and actual Shuttle ascent versus what is practiced in the ground-fixed and motion-based Shuttle Simulators. With the introduction on STS-26 of the current Shuttle escape system, the question of reach performance under launch accelerations was once again raised. The escape system's requirement that each crewman wear a Launch/Entry Suit (LES), parachute harness, and parachute were all anticipated to contribute to a further degradation of reach performance during Shuttle ascent accelerations. In order to answer the reach performance question in a quantitative way, a photogrammetric method was chosen so that the actual reach values and associated envelopes could be captured. This would allow quantitative assessment of potential task performance impact and identify areas where changes to our Shuttle ascent emergency procedures might be required. Also, such a set of reach values would be valid for any similar acceleration profile using the same crew equipment. Potential Space Station applications of this data include predicting reach performance during Assured Crew Return Vehicle (ACRV) operations

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Novel Method In Uncertainty Quantification And Probability Of Collision For Space Objects

The state of a dynamical system and its uncertainty, as defined by its probability density function (PDF), are valuable for numerous fields in science and engineering. There have been numerous methods proposed to estimate and quantify this uncertainty. In as-trodynamics, space situational awareness (SSA) is a major area that relies on uncertainty quantification to estimate a space object’s state and its associated uncertainty. This data is invaluable for making informed decisions regarding probability of collision, tracking, and catalog maintenance. A new method for uncertainty quantification based on orthogonal polynomials and the application of Liouville’s theorem is developed. The method identifies the region of extreme probability at the time of interest and populates that region with structured points. The associated PDF is computed based on the a-priori PDF of the initial conditions and/or the nominal values of the system parameters (e.g. drag coefficient). High dimension orthogonal polynomials are used to approximate the PDF at the target time. Having an analytical expression for the propagated PDF enables rigorous probabilistic analysis. The present method is applied to several problems to compute the probability of collision between two objects. Numerical experiments show an order of magnitude improvement in computational cost versus classical Monte Carlo Methods. The new approach is easy to implement, extensible to higher dimensions, computationally efficient and provides a rigorous approach to address probability of collision problems in SSA