Pointing/roll mechanism for the ultraviolet coronagraph spectrometer

A pointing/roll mechanism for the Ultraviolet Coronagraph Spectrometer (UVCS) is presented along with a description of the mechanism control algorithm. The mechanism, operating in space, will position the 2.1 meter long, 0.7 meter diameter UVCS instrument in pitch and yaw, within a 54 arc-minute half angle cone, and will also allow it to rotate + or - 179.75 deg. After considerable design effort, an optimum mechanical solution was achieved, which meets all scientific requirements as well as weight, volume, and power budgets. Evolution of the mechanism is presented along with the design status

Fractal Rigidity in Migraine

We study the middle cerebral artery blood flow velocity (MCAfv) in humans using transcranial Doppler ultrasonography (TCD). Scaling properties of time series of the axial flow velocity averaged over a cardiac beat interval may be characterized by two exponents. The short time scaling exponent (STSE) determines the statistical properties of fluctuations of blood flow velocities in short-time intervals while the Hurst exponent describes the long-term fractal properties. In many migraineurs the value of the STSE is significantly reduced and may approach that of the Hurst exponent. This change in dynamical properties reflects the significant loss of short-term adaptability and the overall hyperexcitability of the underlying cerebral blood flow control system. We call this effect fractal rigidity.Comment: 4 pages, 6 figure

Construction Project Monitoring with Site Photographs and 4D Project Models

Early and accurate measurement of progress is crucial for the success of a project. Early detection of discrepancies and deviation from the as-planned data allow more time for project participants to identify the best solution. Monitoring the construction progress requires the Project Managers to analyze a lot of as-built data. This time-consuming process is prone to error. To overcome this problem, people have started adopting Building Information Models (BIM) for monitoring the construction progress. In this paper, we have discussed how the site photographs, which are readily available at all project sites, can be effectively used for monitoring the progress. The 4D as-planned model is prepared at the beginning of the project. Then, a 3D model is reconstructed from time-lapsed as-built photos. For any given time, the progress can be tracked by comparing the 4D model and the 3D as-built model. The progress data is extracted by superimposing the reconstructed scene over the 4D as-planned model. The reconstructed model allows the as-built photographs to be geo-registered by the 4D as-planned model. As a result of this comparison, the progress data is then visualized in an AR environment. Progress is visualized in the 4D model using a quadrangle visualization scheme. This type of approach presents a realistic understanding of the construction progress and is a very good communication tool between project participants. We have discussed both interior and exterior construction progress monitoring is this paper

Fractional Langevin model of gait variability

The stride interval in healthy human gait fluctuates from step to step in a random manner and scaling of the interstride interval time series motivated previous investigators to conclude that this time series is fractal. Early studies suggested that gait is a monofractal process, but more recent work indicates the time series is weakly multifractal. Herein we present additional evidence for the weakly multifractal nature of gait. We use the stride interval time series obtained from ten healthy adults walking at a normal relaxed pace for approximately fifteen minutes each as our data set. A fractional Langevin equation is constructed to model the underlying motor control system in which the order of the fractional derivative is itself a stochastic quantity. Using this model we find the fractal dimension for each of the ten data sets to be in agreement with earlier analyses. However, with the present model we are able to draw additional conclusions regarding the nature of the control system guiding walking. The analysis presented herein suggests that the observed scaling in interstride interval data may not be due to long-term memory alone, but may, in fact, be due partly to the statistics