Showing papers in "Mathematics and Computers in Simulation in 1981"

TL;DR: Progress in the application of numerical models, and in the refinement of the physical models, could be greatly accelerated if practitioners were enabled to employ a reliable and economical standard computer program, incorporating the well-established balance laws of fluid mechanics, heat transfer and mass transfer.

TL;DR: A method of automatically detecting and accurately locating discontinuities which occur in many applications of ordinary differential equations, using a Runge-Kutta so chosen that accurate values between integration points can be found by Hermite interpolation.

TL;DR: In this article, the authors present a method for calculating the three-dimensional flow fields in reciprocating internal combustion engines, as a function of space and time, throughout the complete four-stroke cycle, based on a computational procedure which solves the governing elliptic partial-differential equations on a finite-difference grid which expands and contracts with the motion of the piston.

TL;DR: In this article, a new three dimensional oscillator for generating three phases of sinewaves is derived, which is similar to the previous ones (Ref. 1 and 2) in enabling an undistorted stabilized generator.

TL;DR: This paper presents an extended covariance analysis utilizing quasi-linearization techniques on the performance of a nonlinear system with random inputs and initial conditions using the monte carlo method to assess its response to a finite number of initial conditions.

TL;DR: The multigrid solver MGOO is as good as direct solvers for model equations on rectangular domains, even better in special cases, and more generally applicable (variable coefficients).

TL;DR: If stiff differential systems can be divided into stiff and nonstiff subsystems, each subsystem can be integrated with different step sizes, and these methods are called multirate methods and they have been successfully used in several practical problems, especially in real-time simulations.

TL;DR: In this article, a method for the numerical solution of the Hilbert transform integral to obtain the phase corresponding to a given amplitude spectrum is presented, which is based on the assumption that the amplitude spectrum at high and low frequencies can be approximated by constant slopes.

TL;DR: An algorithm has been developed and programmed which fits a minimum number of basic patterns, morphs, to a sequence of data points and the morphs fitted are an indefinite number of occurrences of trends, step functions, and sudden changes.

TL;DR: Computer simulation can serve as a useful tool in the design and construction of process units and the entire mill, as well as comparison of various production and control strategies of the pulp and paper mill processes.

TL;DR: In this paper, the authors considered the application of various accelerated techniques of the Preconditioned Simultaneous Displacement method (PSD method) to the model problem involving Laplace's equation and the generalised Dirichlet problem.

TL;DR: A fast digital hardware system for signal analysis and synthesis, combined with data compression or information rate reduction techniques, provides a powerful tool for a variety of control, communication and signal processing applications.

TL;DR: In this article, the authors extend the application of the extrapolated alternating direction implicit (E.A.D.I.) methods (Hadjidimos, 1970) to obtain the numerical solution of elliptic partial differential equations for regions involving circular symmetry.

TL;DR: In this article, the identification of spatially varying parameters for a partial differential equation describing the thermal behavior of an experimental extruder is presented, where the state equation of the model is given in a discrete functional framework and the identification problem is considered in this framework.

TL;DR: In this article, a proof of the convergence of the DSCT hybrid computer method of solution of the one-dimensional constant coefficients heat equation is given for a particular choice of initial temperature distribution and boundary conditions.

TL;DR: The adaptive filtering and control problem for stochastic distributed systems involving space-dependent random parameters is treated using the partitioning/nonlinear separation approach.

TL;DR: In this article, the authors extend the matrix quadrant factorization techniques which are so applicable for parallel computers to include banded symmetric and centrosymmetric linear systems with a corresponding improvement in computational efficiency.

TL;DR: A method for the hybrid computer solution of a large class of P.D.E.'s, using a Laplace-modified Galerkin approximation, is presented and it is concluded that the proposed method is quite viable.

TL;DR: In this paper, several transformations of non-scalar (vectorial or matricial) sequences are proposed, and their convergence accelerating properties are compared with those of other sequence transformation algorithms.

TL;DR: New techniques for solving extremely stiff systems of differential equations based on a class of implicit Runge-Kutta procedure with complete error estimate are proposed and applied to solving mathematical models of the relaxation problem behind blast waves.

TL;DR: In this article, generalized Extended to the Limit (LU) sparse factorization procedures for the solution of large sparse unsymmetric linear systems of irregular and un-smmetric structure are presented.

TL;DR: For incompressible flows, the addition of artificial vorticity in the vicinity of wall barriers can be useful in the numerical satisfaction of no-slip as mentioned in this paper, which appears to have order one error near the wall.

TL;DR: In this article, the authors investigated the properties of iterative hybrid methods using analog macroblocks with m ⩾ 2 integration lines by overlapping of the blocks pushed over all (N − 1) space lines one after each other.

TL;DR: Socioeconomic-resource models may include aspects of econometric, input-output and system dynamics modeling, together with optimization techniques as mentioned in this paper, and somewhat different models for long- and short-range forecasting may be used in conjunction with one another.

TL;DR: In this article, the standard discrete-time Galerkin method for a linear second order hyperbolic problem is considered, and the L ∞ (H 0 )-error estimates of optimal order are achieved with weaker assumptions on the smoothness of the solution.

TL;DR: In this article, a model has been formulated to investigate the impact on the plants of several harvesting regimes, and the model reproduces the observed dynamics of unperturbed growth very well, and shows reasonable dynamics for harvested plants.

TL;DR: In this article, finite difference approximations for 6, 12, and 24 hours with equal amounts of flow and resting were compared with a continuously flowing system for both clogged and unclogged loamy sand.