Field emission and thermal breakdown are the main mechanisms limiting the accelerating gradient of niobium radio-frequency cavities. Diagnostic tools to study these mechanisms include quality measurements, thermometry, and microscopy. Results presented here demonstrate that micron-size, conducting particles are the source of field emission. Thermal breakdown is caused by a variety of defects su...

One important application of computers in medicine is the merging of various sets of patient data coming from different sources. In the case of image registration, the aim is to determine the translation and rotation by which one data set can be spatially aligned with a second one. Volumetric data (e.g. CT data) can be registered to another volume or to a two-dimensional image (e.g. an X-Ray im...

In this work we apply level of detail techniques to scale up the number of agents in realtime crowd simulations. Level of detail techniques are most studied with respect to geometric simplifications for rendering, but similar ideas are used here for computational simplification for simulations. In particular, we studied methods for computing the paths of agents in a crowd. The main approach for...

We propose two new instructions, swperm and sieve, that can be used to efficiently complete an arbitrary bit-level permutation of an -bit word with or without repetitions. Permutations with repetitions are rearrangements of an ordered set in which elements may replace other elements in the set; such permutations are useful in cryptographic algorithms. On a four-way superscalar processor, we can...

Wireless Standards such as ANSI-41 and WIN are dynamic in nature, continuously evolving to meet subscriber requirements with ever shorter intervals for standards development. The current timelines at which a new version of the specification is to be completed to the needed level of precision, quality and completeness cannot be accommodated using existing specification techniques. A key assumpti...

In this paper, we present a generic validation tool, called FMona. We illustrate its use through the expression of iterative and abstraction methods. These methods are applied for the validation of infinite or parameterized space problems. We propose two techniques to enhance iterative methods by accelerating their convergence. These techniques are expressed in FMona and applied on some examples.

Accelerating superluminal motions were detected recently by multi-epoch Very Long Baseline Interferometry (VLBI) observations. Here, a Linear Accelerating Superluminal Motion (LASM) model is proposed to interpret the observed phenomena. The model provides a direct and accurate way to estimate the viewing angle of a relativistic jet. It also predicts that both Doppler boosting and deboosting eff...