/*
  This is the NAS model from J.H. Poore and C.J. Trammell,
  ``Application of statistical science to testing and
  evaluating software intensive systems,'' Statistics,
  Testing, and Defense Acquisition, National Academy Press,
  Washington, D.C., 1998.

  This model is also used in K.D. Sayre, ``Improved techniques
  for software testing based on Markov chain usage models,''
  Ph.D. Dissertation, The University of Tennessee, Knoxville,
  TN, December 1999.

  Default probabilities are taken from Table 3 of Sayre.
  Distributions u and e are from Table 2 of Poore and Trammell,
  and are the uniform and specific environment distributions,
  respectively.
 
  Copyright (c) 2000
  Software Quality Research Laboratory
  All rights reserved.
*/
  ($ normalize(1) assume(1) $)
u:($ normalize(1) emax      $) // Nothing else necessary for uniform.
e:($ normalize(1) assume(1) $)
model nas
source [(S1) Invocation]
	"Initialize System"
	[(S2) Initialize System]

[(S2) Initialize System]
	($ 0.0698 $)
	e:($ 1/12 $)
	"Reconfigure System"
	[(S3) Reconfigure System]

	($ 0.698 $)
	e:($ 8/12 $)
	"Setup 1"
	[(S4) Setup]

	($ 0.233 $)
	e:($ 3/12 $)
	"Setup 2"
	[(S5) Setup]

[(S3) Reconfigure System]
	"Initialize System"
	[(S2) Initialize System]

[(S4) Setup]
	($ 0.833 $)
	e:($ 3/4 $)
	"Standard Data"
	[(S6) Standard Data]

	($ 0.167 $)
	e:($ 1/4 $)
	"Special Data"
	[(S9) Special Data]

[(S5) Setup]
	($ 0.500 $)
	e:($ 1/12 $)
	"High Rate Data"
	[(S10) High Rate Data]

	($ 0.500 $)
	e:($ 11/12 $)
	"Checkpoint"
	[(S11) Service Decision]

[(S6) Standard Data]
	"Data Analysis"
	[(S7) Data Analysis]

[(S7) Data Analysis]
	"Checkpoint"
	[(S8) Checkpoint]

[(S8) Checkpoint]
	"Initialize System"
	[(S2) Initialize System]

[(S9) Special Data]
	"Data Analysis"
	[(S7) Data Analysis]

[(S10) High Rate Data]
	($ 0.500 $)
	e:($ 3/4 $)
	"Service Decision"
	[(S11) Service Decision]

	($ 0.500 $)
	e:($ 1/4 $)
	"Transform Data"
	[(S15) Transform Data]

[(S11) Service Decision]
	($ 0.698 $)
	e:($ 2/16 $)
	"Setup"
	[(S5) Setup]

	($ 0.0562 $)
	e:($ 1/16 $)
	"High Rate Data"
	[(S10) High Rate Data]

	($ 0.0508 $)
	e:($ 4/16 $)
	"Standard Data"
	[(S12) Standard Data]

	($ 0.0562 $)
	e:($ 4/16 $)
	"Data Analysis"
	[(S13) Data Analysis]

	($ 0.0375 $)
	e:($ 1/16 $)
	"Operator Call"
	[(S14) Operator Call]

	($ 0.0508 $)
	e:($ 3/16 $)
	"Transform Data"
	[(S15) Transform Data]

	($ 0.0508 $)
	e:($ 1/16 $)
	"Checkpoint"
	[(S16) Checkpoint]

[(S12) Standard Data]
	"Service Decision"
	[(S11) Service Decision]

[(S13) Data Analysis]
	"Service Decision"
	[(S11) Service Decision]

[(S14) Operator Call]
	($ 0.500 $)
	e:($ 1/2 $)
	"Service Decision"
	[(S11) Service Decision]

	($ 0.500 $)
	e:($ 1/2 $)
	"Checkpoint"
	[(S16) Checkpoint]

[(S15) Transform Data]
	"Service Decision"
	[(S11) Service Decision]

[(S16) Checkpoint]
	"Termination"
	[(S17) Termination]

sink [(S17) Termination]
end