In this paper we develop novel quantum algorithms based on Quantum Multi-Object Search (QMOS) for convex hulls and general object intersection reporting, with applications to computer graphics. These algorithms are developed and described using standard concepts from computer science by encapsulating the physics of quantum computation within black-box subroutines.

Accurate modeling of pulse propagation and scattering is of great importance to the Navy. In a non-dispersive medium a fourth order in time and space 2-D Finite Difference Time Domain (FDTD) scheme representation of the linear wave equation can be used. However when the medium is dispersive one is required to take into account the frequency dependent attenuation and phase velocity. Using a theory first proposed by Blackstock, the linear wave equation has been modified by adding an additional term (the derivative of the convolution between the causal time domain propagation factor and the acoustic pressure) that takes into account the dispersive nature of the medium. This additional term transforms the calculation from one suitable to a workstation into one very much suited to a largescale computational platform, both in terms of computation and memory. With appropriate distribution of data, good scaling can be achieved up to thousands of processors. Due to the simple structure of the code, it is easily parallelized using three different techniques: pure MPI, pure OpenMP and a hybrid MPI/OpenMP. We use this real life application to evaluate the performance of the latest multi-cpu/multicore platforms available from the DoD HPCMP.

We describe our experiences porting and tuning three scientific programs to the Cray MTA-2, paying particular attention to the problems posed by I/O. We have measured the performance of each of the programs over many different machine configurations and we report on the scalability of each program. In addition, we compare the performance of the MTA with that of an SGI Origin running all three programs.

The paper describes a computer modeling and simulation system that supports computational steering, which is an effort to make the typical simulation workflow more efficient. Our system provides an interface that allows scientists to perform all of the steps in the simulation process in parallel and online. It uses a standard network flow visualization package, which has been extended to display graphical output in an immersive virtual environment such as a CAVE. Our system allows scientists to interactively manipulate simulation parameters and observe the results. It also supports inverse steering, where the user specifies the desired simulation result, and the system searches for the simulation parameters that achieve this result. Taken together, these capabilities allow scientists to more efficiently and effectively understand model behavior, as well as to search through simulation parameter space. The paper is also a case study of applying our system to the problem of simulating microwave interactions with missile bodies. Because these interactions are difficult to study experimentally, and have important effects on missile electronics, there is a strong desire to develop and validate simulation models of this phenomena.

We describe the efforts being carried out at the Naval Research Laboratory (NRL) towards VR scientific visualization. We are exploring scientific visualization in an immersive virtual environment: the NRL's CAVE/sup TM/-like device known as GROTTO (Graphical room for observation, Training and Tactical Orientation). We describe the AVS GROTTO viewer, a VR interface to the AVS visualization system. The AVS GROTTO viewer has been used by a number of scientists in current, ongoing research projects within NRL.

This case study describes a technique for the three-dimensional analysis of the internal microscopic structure (microstructure) of materials. This technique consists of incrementally polishing through a thin layer (approximately 0.2 /spl mu/m) of material, chemically etching the polished surface, applying reference marks, and performing optical or scanning electron microscopy on selected areas. The series of images are then processed employing AVS and other visualization software to obtain a 3D reconstruction of the material. We describe how we applied this technique to an alloy steel to study the morphology, connectivity, and distribution of cementite precipitates formed during thermal processing. The results showed microstructural features not previously identified with traditional 2D techniques.