abstract: Grassland habitat restoration activities are occurring within the semi-arid grasslands of the Agua Fria National Monument located 65 km north of Phoenix, AZ. The goal of these restoration activities is to reduce woody species encroachment, remove lignified plant materials and recycle nutrients within the ecosystem thus improving range conditions for both wildlife species and livestock. Broadcast burning, juniper thinning and slash pile burns are the principle tools used to accomplish resource objectives. Line cover, belt transect, densities, heights and biomass of vegetation data were collected to determine the response of the vegetative community to habitat restoration activities. Principal Component Analysis (PCA) was used to reduce data analysis to the more influential factors. Regression analysis was conducted for statistically significant response variables. Quadratic regression analysis found low predictive values. In broadcast burn treatment units, all important factors as identified by PCA had low predictive factors but significantly differed (R2 <0.01, p<0.05) between unburned and the years post treatment. Regression analysis found significant, albeit weak, relationships between time since treatment and independent variables. In pile burn treatment units, data reduction by PCA was not possible in a biologically meaningful way due to the high variability within treatment units. This suggests the effect of juniper encroachment on grassland vegetation persists long after junipers have been cut and burned. This study concluded that broadcast burning of the central Arizona grasslands does significantly alter many components of the vegetative community. Fuels treatments generally initially reduced both perennial woody species and grasses in number and height for two year post fire. However, palatable shrubs, in particular shrubby buckwheat, were not significantly different in broadcast burn treatment areas. The vegetative community characteristics of juniper encroached woodlands of central Arizona are unaffected by the removal and burning of junipers aside from the removal of hiding cover for predators for multiple years. It is recommended that habitat restoration activities continue provided the needs of wildlife are considered, especially pronghorn, with the incorporation of state and transition models specific to each of the respective ecological site descriptions and with the consideration of the effects of fire to pronghorn fawning habitat. / Dissertation/Thesis / M.S. Applied Biological Sciences 2014

We consider a new approach to digital human simulation, using Model Predictive Control (MPC). This approach permits a virtual human to react online to unanticipated disturbances that occur in the course of performing a task. In particular, we predict the motion of a virtual human in response to two different types of real world disturbances: impulsive and sustained. This stands in contrast to prior approaches where all such disturbances need to be known a priori and the optimal reactions must be computed off line. We validate this approach using a planar 3 degrees of freedom serial chain mechanism to imitate the human upper limb. The response of the virtual human upper limb to various inputs and external disturbances is determined by solving the Equations of Motion (EOM). The control input is determined by the MPC Controller using only the current and the desired states of the system. MPC replaces the closed loop optimization problem with an open loop optimization allowing the ease of implementation of control law. Results presented in this thesis show that the proposed controller can produce physically realistic adaptive simulations of a planar upper limb of digital human in presence of impulsive and sustained disturbances.