1 Abstract This paper describes an algorithm for cyclic distributed garbage collection and its implementation. The algorithm is an extension of reference-listing that collects cyclic garbage. It uses back-tracing instead of mark-and-sweep to eliminate the need of global synchronization. First, by using a special heuristic the algorithm chooses an object that is likely to be garbage (suspect). T...

Realistic acoustic modeling is essential for spatializing sound in distributed virtual environments where multiple networked users move around and interact visually and aurally in a shared virtual world. Unfortunately, current methods for computing accurate acoustical models are not fast enough for real-time auralization of sounds for simultaneously moving sources and receivers. In this paper, ...

UNLABELLED This retrospective analysis of existing patient data had institutional review board approval and was performed in compliance with HIPAA. No informed consent was required. The purpose of the study was to develop and validate an algorithm for automated segmentation of the left ventricular (LV) cavity that accounts for papillary and/or trabecular muscles and partial voxels in cine magne...

The accurate and efficient tracing of streamlines is fundamental to any streamline-based simulation method. For grids with irregular cell geometries, such as corner-point grids with faults or Voronoidiagram (pebi) grids, most efforts to trace streamlines have been focused on subdividing irregular cells into sets of simpler subcells, typically hexahedra or simplices. Then one proceeds by reconst...

We implemented a fully-3D ordered subsets expectation maximization (OSEM) algorithm with compensation of attenuation, distance-dependent blurring (DDB) and sensitivity modeling for SPECT performed with cone-beam collimator (CBC). The experimentally obtained detector response to point sources across FOV was fitted to a twodimensional Gauss function with its width (FWHM) varied linearly with the ...

In this paper we propose a simple but effective method to modify a BVH based on ray distribution for improved ray tracing performance. Our method starts with an initial BVH generated by any state-of-the-art offline algorithm. Then by traversing a small set of sample rays we collect statistics at each node of the BVH. Finally, a simple but ultra-fast BVH contraction algorithm modifies the initia...

We posit that swarm intelligence can be applied to effectively address requirements engineering problems. Specifically, this paper demonstrates the applicability of swarm intelligence to the requirements tracing problem using two techniques: a simple swarm algorithm and a pheromone swarm algorithm. The techniques have been validated using two real-world datasets from two problem domains. The si...

This paper proposes an improved ray tracing technique that can reproduce a realistic image based on the spectral characteristic of real lights and objects. The proposed algorithm is able to generate a realistic image that simulates the physical quantity of light energy incoming toward a viewer. First, an accurate image is reproduced using the backward ray tracing method and by tracing the spect...

SIGHT-2 is a multiprocessor system that is intended to efficiently execute the ray tracing algorithm. To achieve high efficiency, three kinds of parallel execution mechanisms; (i) a multiprocessor configuration, (ii) a parallel execution of three dimensional vector operations, and (iii) functionally distributed parallel processing are introduced. Owing to the latter two techniques, each process...

Classical ray-tracing algorithms compute radiance returning to the eye along one or more sample rays through each pixel of an image. The output of a ray-tracing algorithm, although potentially photorealistic, is a two-dimensional quantity { an image array of radiance values { and is not directly useful from any viewpoint other than the one for which it was computed. This paper makes several con...