Initial System Configuration Research Articles

Self-Stabilizing Algorithms for Tree Metrics

We present algorithms for finding the diameter, centroid(s), and median(s) for tree structured networks subject to transient faults. In our solutions, the system reaches its final correct configuration in a finite time after the faults cease. The fault-tolerance is achieved using Dijkstra's paradigm of self-stabilization. A self-stabilizing algorithm, regardless of the initial system configuration, converges, in finite time, to a set of legitimate configurations.

A performance evaluation model for FMS based on RAM and LCC using FACTOR/AIM

The objective of this study is to develop a general design and performance evaluation model for the system designers in the initial design phase of the integrated manufacturing system based on the RAM(Reliability, Availability and Maintainability) and life cycle cost(LCC). The methodology proposed in this research includes the following three-step generative approach. First, a deterministic approach to find the optimal system configuration for the initial system configuration is considered under the assumption that the system availability is one(no failure and maintenance), and in second step a stochastic simulation model based on RAM and LCC is developed. Using the results of this two-stage simulation, a system performance index(SPI) was developed for the performance evaluation of the system. In the last step we developed a simulation model using FACTOR/AIM to consider a variety of performance factors and compared the results through a sample example.

On Positive Harris Recurrence of Multiclass Queueing Networks: A Unified Approach Via Fluid Limit Models

It is now known that the usual traffic condition (the nominal load being less than 1 at each station) is not sufficient for stability for a multiclass open queueing network. Although there has been some progress in establishing the stability conditions for a multiclass network, there is no unified approach to this problem. In this paper, we prove that a queueing network is positive Harris recurrent if the corresponding fluid limit model eventually reaches zero and stays there regardless of the initial system configuration. As an application of the result, we prove that single class networks, multiclass feedforward networks and first-buffer-first-served preemptive resume discipline in a reentrant line are positive Harris recurrent under the usual traffic condition.

Using color-image maps to study collisions in the three-body problem

Color-image maps are generated through computer-based simulations to study the evolution of a system of three bodies interacting under classical gravitational forces. These image maps partition the set of possible initial-system configurations into regions that exhibit similar evolutionary characteristics. This resembles the technique used to produce color images of the Mandelbrot set. A restricted case of the three-body problem, in which the initial velocities of all three bodies are zero and the bodies are all of equal mass, is examined in detail. Image maps of the time to collision (assuming a finite radius) as a function of initial configuration are presented. Symmetries of the resulting maps are analyzed for invariants by means of transformations of scale.

Constraints to Possible Progenitor Systems of PSR 1831-00

Numerical computations were carried out to simulate the evolution of the recently discovered radio pulsar binary PSR 1831-00 with a very low mass function (Porb = 1.81 days, Dewey et al. 1986). These show that the minimum value of the initial mass of the progenitor of the mass-losing secondary is about 1 M⊙. All computed systems with a final period equal to the observed one, and an initial progenitor mass of 1 M⊙ have an age of the order of the Hubble time (∼ 1.3 × 1010years). For a 1.5 M⊙ progenitor of the mass-losing secondary we find that the final (= presently observed) orbital period sets strong constraints to the possible initial system configuration: the binary period should have been such that the 1.5 M⊙ star was just at the onset of the over-all contraction phase (Porb = 0.74 days, XC = 0.05) when it began to fill its Roche-lobe, and the initial mass or the compact mass-accreting star must have been < 0.85 M⊙. (This star was then presumably a white dwarf, which later collapsed due to the accretion). For example, the final period and remnant secondary mass for a system with an initial configuration of 1.5 + 0.8 M⊙ are 1.83 days and 0.20 M⊙, respectively.If one would start out from a more evolved initial state of the 1.5 M⊙ secondary than the end of the overall-contraction phase, the maximum initial mass of the compact object will become drastically smaller and the final remnant mass of the secondary becomes larger than 0.20 M⊙ in all cases.Calculations for a 2.0 M⊙ progenitor of the secondary suggest that if such a progenitor can produce the present system, the initial mass of the accreting primary was at maximum 1.30 M⊙.All the calculations were performed with the inclusion of magnetic braking in so far as the extent of the convective envelope allowed this (see Pylyser & Savonije 1986, in preparation). The effects of the explosion effects due to the accretion induced collapse of the white dwarf were not taken into account.

Development Aspects of Migration in Third World Settings: A Simulation, with Implications for Urbanization

A simulation of the interrelationships between development and migration in developing countries is presented. "Development is represented as the diffusion of demographic transition, employment opportunities, and formal and communication channels, which in turn affect informal communications and the overall economic base. The simulation falls within the genre of neoclassical development models, but, unlike many, explicitly explores the long-run aspects of landscape evolution." The results generally "conform with expectations hypothesized in earlier research, including phenomena such as polarization reversal, converging regional disparities, and low-level equilibrium traps at small remote places where continual resource drain thwarts the agglomeration economies necessary for sustained growth. [The authors] also find that the initial urban system configuration has little effect on the final configuration, and that only urban size diseconomies are likely to alter significantly the size, spatial distribution, and spatial characteristics of the urban system."

Some comments on single-server queuing methods and some new results

1. Introduction. Over the past few years, the theory of single-server queues has grown substantially. Much of the effort expended has been applied to the study of transient multivariate queuing processes in continuous time, i.e. to the study of joint time-dependent distributions of two or more system variables given some known initial system configuration. A variety of methods have been employed in these studies to accommodate general interarrival and service time distributions, among them Erlang's method of fictitious phases, the method of supplementary variables, the extended imbedded chain method, and the semi-Markov method. In the first part of this paper an informal review of these transient studies and of the methods employed is given.