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Furchtgott, D. G.

Publications and source records attributed to Furchtgott, D. G..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

A performability solution method for degradable nonrepairable systems

The present performability model-solving algorithm identifies performance with 'reward', representing the state behavior of a system S by a finite-state stochastic process and determining reward by means of reward rates that are associated with the states of the base model. A general method is obtained for determining the probability distribution function of the performance (reward) variable, and therefore the performability, of the corresponding system. This is done for bounded utilization periods, and the result is an integral expression which is either analytically or numerically solvable.

Furchtgott, D. G.↗
NASA NTRS1980

Performability evaluation of the SIFT computer

The paper deals with the models, techniques, and evaluation methods that were successfully used to test the performance of the SIFT degradable computing system. The performance of the computer plus its air transport mission environment is modeled as a random variable, taking values in a set of 'accomplishment level'. The levels are defined in terms of four attributes of total system (computer plus environment) behavior, namely safety, no change in mission profile, no operational penalties, and no economic penalties. The base model of the total system is a stochastic process, whose states describe the internal structure of SIFT and the relevant conditions of its computational environment. Base model state trajectories are related to accomplishment levels via a special function, and solution methods are then used to determine the performability of the total system for various parameters of the computer and environment.

Meyer, J. F.↗
NASA NTRS1979

METAPHOR (version 1): Users guide

General information concerning METAPHOR, an interactive software package to facilitate performability modeling and evaluation, is presented. Example systems are studied and their performabilities are calculated. Each available METAPHOR command and array generator is described. Complete METAPHOR sessions are included.

Furchtgott, D. G.↗
NASA NTRS1979

Performability evaluation of the SIFT computer

Performability modeling and evaluation techniques are applied to the SIFT computer as it might operate in the computational evironment of an air transport mission. User-visible performance of the total system (SIFT plus its environment) is modeled as a random variable taking values in a set of levels of accomplishment. These levels are defined in terms of four attributes of total system behavior: safety, no change in mission profile, no operational penalties, and no economic process whose states describe the internal structure of SIFT as well as relavant conditions of the environment. Base model state trajectories are related to accomplishment levels via a capability function which is formulated in terms of a 3-level model hierarchy. Performability evaluation algorithms are then applied to determine the performability of the total system for various choices of computer and environment parameter values. Numerical results of those evaluations are presented and, in conclusion, some implications of this effort are discussed.

Meyer, J. F.↗
NASA NTRS1979

METAPHOR: Programmer's guide, Version 1

The internal structure of the Michigan Evaluation Aid for Perphormability (METAPHOR), an interactive software package to facilitate performability modeling and evaluation is described. Revised supplemented guides are prepared in order to maintain an up-to-date documentation of the system. Programmed tools to facilitate each step of performability model construction and model solution are given.

Furchtgott, D. G.↗