Simulations of particles in fluid flows are of great interest to numerous industries using sedimentation, fluidization, lubricated transport, and hydraulic fracturing of hydrocarbon reservoirs. Simulating incompressible viscoelastic flows with millions of rigid particles is computationally a very challenging problem. In addition to using sophisticated modeling techniques and numerical algorithm...

This paper describes the application of a continuous daily water balance model called SWAT(Soil and Water Assessment Tool) for the conterminous U.S. The local water balance is represented by four control volumes; (1) snow, (2) soil profile, (3) shallow aquifer, and (4) deep aquifer. The components of the water balance are simulated using "storage" models and readily available input parameters. ...

In this paper, an optimistic parallel and distributed logic simulator, XTW, is proposed. In XTW, a new event scheduling mechanism, XEQ, and a new rollback procedure, rb-messages, are proposed for use in optimistic logic simulation. XTW groups LPs into clusters, and makes use of a multi-level queue, XEQ, to schedule events in the cluster. XEQ has an O(1) event scheduling time complexity. Our new...

This document details a rationalisation study on the production of shop-prefabricated parts supported by simulation to analyse potential operating alternatives. The goal was quite specific: to improve productivity and so reduce production costs. Since the study was carried out while the workshop was fully operational, no changes that would have involved stoppages in workshop production could be...

Simulation has always been an indispensable tool in the design and analysis of telecommuni cation networks Due to performance limitations of the majority of simulators usually network simulations have been done for rather small network models and for short time scales In con trast many di cult design problems facing today s network engineers concern the behavior of very large hierarchical multi...

Accurate and efficient simulation of large parallel applications can be facilitated with the use of direct execution and parallel discrete-event simulation. This paper describes MPI-SIM, a direct execution-driven parallel simulator designed to predict the performance of existing MPI and MPI-IO application. MPI-SIM can be used to predict the performance of these programs as a function of archite...

Qualitative simulation faces an intrinsic problem of scale: the number of limit hypotheses grows exponentially with the number of parameters approaching limits. We present a method called TimeScale Abstraction for structuring a complex system as a hierarchy of smaller, interacting equilibrium mechanisms. Within this hierarchy, a given mechanism views a slower one as being constant, and a faster...

Scale-invariant timing has been observed in a wide range of behavioral experiments. The scale-invariant firing property of recently described time cells provides a possible neural substrate for this behavior. Earlier work proposed a mathematical model that generates scale-invariant time cells based on neurons with long time constants and an approximation of inverse Laplace transform. This paper...

This paper presents a method to simulate high density non overlapping sphere structures with anisotropy and heterogeneity.

We contrast the concepts of computational simulation as practiced in computer assisted design with that of numerical modeling of geology and other observational sciences in which controlled experiments are not available. We highlight the role of the modeller in subjectively weighting observations, modelling and experience to find a preferred geological model.