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Showing papers in "Mathematical and Computer Modelling in 1999"



Journal ArticleDOI
TL;DR: The connectivity of a team is highly correlated with its performance; different types of attractors occur in phase space depending on the team's connectivity and performance level: low performance teams show point attractors, medium performance Teams show limit cycles, and high performance teams shows low-dimensional chaotic attractors.

218 citations


Journal ArticleDOI
TL;DR: In this paper, the spatio-temporal dynamics of a prey-predator community is described by two reaction-diffusion equations, and it is shown that for a class of initial conditions the spatiotemporal system dynamics resembles a phase transition between a regular and an irregular phase, separated by a moving boundary.

175 citations


Journal ArticleDOI
TL;DR: In this paper, the authors apply various estimation procedures to synthetic periodic time series in order to verify the performance of each estimation method and to determine which estimators should be used when periodicity may be present.

146 citations


Journal ArticleDOI
TL;DR: In this article, some new iterative methods for solving general monotone mixed variational inequalities by using the updating technique of the solution are considered and the convergence analysis of these new methods is considered.

127 citations


Journal ArticleDOI
TL;DR: The Potts model, an energy minimisation method, is used to simulate the growth of a benign avascular tumour embedded in normal tissue, including cell sorting that occurs between tumour and normal cells, due to the variation of adhesion between different cell types.

118 citations


Journal ArticleDOI
TL;DR: A survey of retrial queues with two types of calls and new results of several models are presented, including the M"1, M"2/G/1 retrial queue and its variations.

115 citations


Journal ArticleDOI
TL;DR: In this article, the authors used fast Fourier transforms to approximate the stable density functions of stable Paretian distributions and compared the performance of the estimation approach to that of a widely used quantile estimator.

115 citations


Journal ArticleDOI
TL;DR: An algorithm for calculating the probability density function of the asymmetric stable Paretian distribution is presented, which is computationally efficient, easily implemented, and of similar accuracy as existing algorithms.

102 citations


Journal ArticleDOI
TL;DR: The four parameter family of hyperbolic distributions fits very well the daily returns of the German stocks that have been included in the DAX during the period 1974 and 1992 as mentioned in this paper.

96 citations


Journal ArticleDOI
TL;DR: In this paper, the authors consider a network of three identical neurons whose dynamics is governed by the Hopfield's model with delay to account for the finite switching speed of amplifiers (neurons).

Journal ArticleDOI
TL;DR: The authors generalises the celebrated Black and Scholes [1] European option pricing formula for a class of logstable asset price models and shows that theoretical option prices have the potential to explain the implied volatility smiles evident in the market.

Journal ArticleDOI
TL;DR: A combination of results from two related one-dimensional models are examined, and the size of the critical size defect is predicted, which is defined as the smallest intraosseous wound that does not heal by bone formation during the lifetime of the animal being studied.

Journal ArticleDOI
TL;DR: By using averaging functions, this paper obtained some criteria for the oscillation of half-linear differential equation [p(t) @lx'(t), lx' (t)@lx')@a^-^-1 x'(T)]' + q(t, lx', lx(t'), lx '(t)'@l x', l x' (T)@a-^1x(T) = 0, @a $@?0, where p @e C^1([t"0,

Journal ArticleDOI
TL;DR: In this article, two domain partitions are proposed that give rise to region configurations practically meaningful for the realizability of lattice models, and discussed and connected with the domain partition generated by the set of boundaries, frequently considered when dealing with PWL functions.

Journal ArticleDOI
TL;DR: In this paper, the authors deal with nonlinear hydrodynamic modelling of traffic flow on roads and with the solution of related nonlinear initial and boundary value problems, and provide a critical analysis and an overview on research perspectives.

Journal ArticleDOI
TL;DR: In this article, a program is described to calculate a general @a-stable density for @a > 0.75 and any skewness value @b, where b is defined as the skewnness value of the distribution.

Journal ArticleDOI
TL;DR: In this article, the authors considered the retrial group of finite capacity and geometric loss and derived the joint distribution of two queue lengths, the waiting time distribution and the distribution of the busy period from these results, they obtained the blocking probability, the mean waiting time, and the mean queue lengths.

Journal ArticleDOI
TL;DR: In this paper, a bivariate Markov process is introduced, where the state space is a lattice semistrip E = {0,1,2,3} x Z"+.

Journal ArticleDOI
TL;DR: In this paper, a new class of singly-implicit extended one-step methods for numerical integration of second-order initial-value problems was introduced, with oscillating solutions.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed an epidemic model, taking into account the phenomenon of frailty in the various transition rates, and analyzed its effect on the observable rates, showing that age-dependent parameters may arise from heterogeneity in situations where no explicit age-dependence is built into the model.

Journal ArticleDOI
TL;DR: In this paper, the authors propose different heuristic algorithms for flow shop scheduling problems, where the jobs are partitioned into groups or families, and the objective function is the makespan as well as the weighted sum of completion times of the jobs.

Journal ArticleDOI
TL;DR: In this paper, a sufficient condition for existence of a steady-state distribution is derived for a BMAP/G/1 retrial queueing system and an approximate algorithm for calculating the stationary state probabilities is proposed.

Journal ArticleDOI
TL;DR: In this article, the authors examined the more realistic two-dimensional model of a circular wound of uniform depth to see what modifications are to be found, as compared with the one dimensional model, in studying the critical size defect phenomenon.

Journal ArticleDOI
TL;DR: In this paper, a hybrid parallelizable O(n) algorithm for the modeling of the dynamic behavior of multi-rigid-body chain systems is presented, which is based on the cutting of certain system interbody joints so that largely independent multibody subchain systems are formed.

Journal ArticleDOI
TL;DR: In this article, the set-valued mixed quasi-variational inequalities (SVMVI) were introduced and studied, which is a new class of variational inequalities, and the resolvent operator technique was used to establish the equivalence among generalized SVMVI, fixed-point problems and the setvalued implicit resOLV equations.

Journal ArticleDOI
TL;DR: In this article, a nonlinear mathematical model is developed analytically to study the flow characteristics of blood through an artery in the presence of multistenoses when it is subjected to whole body acceleration.

Journal ArticleDOI
TL;DR: In this article, a class of multivariate geometric stable laws that can be used in modeling multivariate financial portfolios of securities are described. But their main features, peakedness and heavy tails, are not well captured by the geometric stable model.

Journal ArticleDOI
TL;DR: An algorithm of optimal calculation of stationary performance measures of Markov models with retrials is suggested, which gives a great reduction of computer resources in estimating the performance Measures of models with retrieals.

Journal ArticleDOI
T. Hanschke1
TL;DR: In this article, the authors describe a multiserver repeated order queue with an unlimited number of sources, for which the underlying queueing process can be represented as a level-dependent quasi-birth-and-death process.