Browsing by Subject "embedding"
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Item In-Jet Tracking Efficiency Analysis for the STAR Time Projection Chamber in Polarized Proton-Proton Collisions at sqrt(s) = 200GeV(2012-07-16) Huo, LiaoyuanAs one of the major mid-rapidity tracking devices of the STAR detector at the Relativistic Heavy-Ion Collider (RHIC), the Time Projection Chamber (TPC) plays an important role in measuring trajectory and energy of high energy charged particles in polarized proton-proton collision experiments. TPC's in-jet tracking efficiency represents the largest systematic uncertainty on jet energy scale at high transverse momentum, whose measurement contributes to the understanding of the spin structure of protons. The objective of this analysis is to get a better estimation of this systematic uncertainty, through methods of pure Monte-Carlo simulation and real- data embedding, in which simulated tracks are embedded into real-data events. Be- sides, simulated tracks are also embedded into Monte-Carlo events, to make a strict comparison for the uncertainty estimation. The result indicates that the unexplained part of the systematic uncertainty is reduced to 3.3%, from a previous quoted value of 5%. This analysis also suggests that future analysis, such as embedding jets into zero-bias real data and analysis with much higher event statistics, will benefit the understanding of the systematic uncertainty of the in-jet TPC tracking efficiency.Item Physical Simulation of an Embedded Surface Mesh Involving Deformation and Fracture(2012-07-16) Clack, BillySimulating virtual objects which can deform or break apart within their environments is now common in state-of-the-art virtual simulations such as video games or surgery simulations. Real-time performance requires a physical model which provides an approximation to the true solution for fast computations but at the same time provides enough believability of the simulation to the user. Recent research in object deformation and fracture has revolved around embedding portions of the simulation for graphical display inside a much simpler physical domain which is invisible to the user. Embedding complex geometry in a simpler domain allows for very complex effects to occur in a much more robust and computationally efficient manner. This thesis explores a novel method to efficiently embed a high-resolution surface mesh inside a coarse tetrahedral physical mesh for the purposes of interactive simulation and display. A technique to display interior regions as solid geometry without explicitly re-meshing the graphical mesh during fracture has been explored and developed. Keeping the graphical mesh static in memory during simulation allows the geometry to be off-loaded to the GPU while shaders can be utilized to only display portions of the geometry which are locally contained within the physical mesh. Recent advances in GPU technology have also been exploited in order to provide an increase in visual fidelity and help achieve the illusion that the virtual object itself is breaking apart in a physically plausible manner.