Motor Control Insights on Walking Planner and its Stability

The application of biomechanic and motor control models in the control of bidedal robots (humanoids, and exoskeletons) has revealed limitations of our understanding of human locomotion. A recently proposed model uses the potential energy for bipedal structures to model the bipedal dynamics, and it allows to predict the system dynamics from its kinematics. This work proposes a task-space planner for human-like straight locomotion that target application of in rehabilitation robotics and computational neuroscience. The proposed architecture is based on the potential energy model and employs locomotor strategies from human data as a reference for human behaviour. The model generates Centre of Mass (CoM) trajectories, foot swing trajectories and the Base of Support (BoS) over time. The data show that the proposed architecture can generate behaviour in line with human walking strategies for both the CoM and the foot swing. Despite the CoM vertical trajectory being not as smooth as a human trajectory, yet the proposed model significantly reduces the error in the estimation of the CoM vertical trajectory compared to the inverted pendulum models. The proposed model is also able to asses the stability based on the body kinematics embedding in currently used in the clinical practice. However, the model also implies a shift in the interpretation of the spatiotemporal parameters of the gait, which are now determined by the conditions for the equilibrium and not \textit{vice versa}. In other words, locomotion is a dynamic reaching where the motor primitives are also determined by gravity

Greetings from the Lower Rio Grande Valley of Texas Souvenir Folder [postcards]

Souvenir postcards promoting the lower Rio Grande Valley of Texas for vacation travel, agriculture, and ideal living conditions.https://scholarworks.utrgv.edu/lrgv/1028/thumbnail.jp

On-Scene Determination of Driver Crash Causation and Avoidance Maneuvers in Rear-end Collisions

ABSTRACT Rear-end collisions are one of the most frequent crash types in the U.S. Pre-Collision System (PCS) have been developed to mitigate the frequency and severity of rear-end collisions. The potential effectiveness of these systems, however, depends on the driver's state and their attempted avoidance maneuvers. This study utilized the National Motor Vehicle Crash Causation Survey (NMVCCS), a unique nationally representative dataset focused on crash causation, to quantify contributing factors in rear-end collisions and the avoidance maneuvers attempted by drivers of the striking vehicle. For a case to be included in NMVCSS, the crash site had to be visited by an investigator prior to the scene being cleared. Rear-end collisions were more likely to involve a driver that was following too closely, inattentive, distracted by a non-driving activity, focusing on external factors, exhibiting inadequate surveillance, and making false assumptions of other drivers' actions compared to other frontal collisions. Compared to other frontal collisions, rear-end collisions were more likely to have occurred on roadways with traffic flow restrictions, speed limits at highway speeds, multiple lanes, and relation to a junction (e.g. intersections, on-ramps, merging zones). In 72% of rear-end collision the driver attempted an avoidance maneuver. Of those drivers attempting an avoidance maneuver, 67% only applied the brakes, 27% applied the brakes with steering, and 6% only steered. Conversing and non-driving activities were found to be significant factors indicating the lack of an avoidance maneuver in rear-end collisions. In all rear-end collisions, Forward Collision Warning and Pre-Crash Brake Assist could be potentially effective in 84% of crashes, while Autonomous Braking could be effective in 90% of crashes

Identification and Analysis of National Airspace System Resource Constraints

This analysis is the deliverable for the Airspace Systems Program, Systems Analysis Integration and Evaluation Project Milestone for the Systems and Portfolio Analysis (SPA) focus area SPA.4.06 Identification and Analysis of National Airspace System (NAS) Resource Constraints and Mitigation Strategies. "Identify choke points in the current and future NAS. Choke points refer to any areas in the en route, terminal, oceanic, airport, and surface operations that constrain actual demand in current and projected future operations. Use the Common Scenarios based on Transportation Systems Analysis Model (TSAM) projections of future demand developed under SPA.4.04 Tools, Methods and Scenarios Development. Analyze causes, including operational and physical constraints." The NASA analysis is complementary to a NASA Research Announcement (NRA) "Development of Tools and Analysis to Evaluate Choke Points in the National Airspace System" Contract # NNA3AB95C awarded to Logistics Management Institute, Sept 2013

Estimation of Physiological Tremor from Accelerometers for Real-Time Applications

Accurate filtering of physiological tremor is extremely important in robotics assisted surgical instruments and procedures. This paper focuses on developing single stage robust algorithms for accurate tremor filtering with accelerometers for real-time applications. Existing methods rely on estimating the tremor under the assumption that it has a single dominant frequency. Our time-frequency analysis on physiological tremor data revealed that tremor contains multiple dominant frequencies over the entire duration rather than a single dominant frequency. In this paper, the existing methods for tremor filtering are reviewed and two improved algorithms are presented. A comparative study is conducted on all the estimation methods with tremor data from microsurgeons and novice subjects under different conditions. Our results showed that the new improved algorithms performed better than the existing algorithms for tremor estimation. A procedure to separate the intended motion/drift from the tremor component is formulated

Affinity Purification of Biologically Active andInactive Forms of Recombinant Human Protein C Produced in Porcine Mammary Gland

Recombinant human protein C (rhPC) secreted in the milk of transgenic pigs was studied. \u27Ikansgenes having different regulatory elements of the murine milk protein, whey acidic protein, were used with cDNA and genomic human protein C (hPC) DNA sequences to obtain lower and higher expressing animals. The cDNA pigs had a range of expression of about 0.1-0.5 g/l milk. Two different genomic hPC pig lines have expressed 0.3 and 1-2 g/l, respectively. The rhPC was first purified at yields greater than 60 per cent using a monoclonal antibody (mAb) to the activation site on the heavy chain of hPC. Subsequent immunopurification with a calcium-dependent mAb directed to the y-carboxyglutamic acid domain of the light chain of hPC was used to fractionate a population having a higher specific anticoagulant activity in vW. The higher percentages of Ca2+-dependent conformers isolated from the total rhPC by immunopurification correlated well with higher specific activity and lower expression. A rate limitation in y-carboxylation of rhPC was clearly identified for the higher expressing animals. Thus, transgenic animals with high expression levels of complex recombinant proteins produced a lower percentage of biologically active protein