Designing a computer system diagnosis model
打印机故障诊断模型
总结
package cn.edu.gdut.ppl.figaro.test
import com.cra.figaro.algorithm.factored.VariableElimination
import com.cra.figaro.language._
import com.cra.figaro.library.compound._
/**
* Created by HuGuodong on 2017/12/20.
*/
object PrinterProblem {
val printerPowerButtonOn = Flip(0.95)
val tonerLevel = Select(0.7 -> 'high, 0.2 -> 'low, 0.1 -> 'out)
val tonerLowIndicatorOn =
If(printerPowerButtonOn,
CPD(tonerLevel,
'high -> Flip(0.2),
'low -> Flip(0.6),
'out -> Flip(0.99)),
Constant(false))
val paperFlow = Select(0.6 -> 'smooth, 0.2 -> 'uneven, 0.2 -> 'jammed)
val paperJamIndicatorOn =
If(printerPowerButtonOn,
CPD(paperFlow,
'smooth -> Flip(0.1),
'uneven -> Flip(0.3),
'jammed -> Flip(0.99)),
Constant(false))
val printerState =
Apply(printerPowerButtonOn, tonerLevel, paperFlow,
(power: Boolean, toner: Symbol, paper: Symbol) => {
if (power) {
if (toner == 'high && paper == 'smooth) 'good
else if (toner == 'out || paper == 'out) 'out
else 'poor
} else 'out
})
val softwareState = Select(0.8 -> 'correct, 0.15 -> 'glitchy, 0.05 -> 'crashed)
val networkState = Select(0.7 -> 'up, 0.2 -> 'intermittent, 0.1 -> 'down)
val userCommandCorrect = Flip(0.5)
val numPrintedPages = RichCPD(userCommandCorrect, networkState,
softwareState, printerState,
(*, *, *, OneOf('out)) -> Constant('zero),
(*, *, OneOf('crashed),*) -> Constant('zero),
(*, OneOf('down), *, *) -> Constant('zero),
(OneOf(false), *, *, *) -> Select(0.3 -> 'zero, 0.6 -> 'some, 0.1 -> 'all),
(OneOf(true), *, *, *) -> Select(0.01 -> 'zero, 0.01 -> 'some, 0.98 -> 'all))
val printsQuickly = Chain(networkState, softwareState,
(network: Symbol, software: Symbol) =>
if (network == 'down || software == 'crashed)
Constant(false)
else if (network == 'down || software == 'crashed)
Flip(0.5)
else Flip(0.9))
val goodPrintQuality = CPD(printerState,
'good -> Flip(0.95),
'poor -> Flip(0.3),
'out -> Constant(false))
val printResultSummary =
Apply(numPrintedPages, printsQuickly, goodPrintQuality,
(pages: Symbol, quickly: Boolean, quality: Boolean) =>
if (pages == 'zero) 'none
else if (pages == 'some || !quickly || !quality) 'poor
else 'excellent)
def step1() {
val answerWithNoEvidence = VariableElimination.probability(printerPowerButtonOn, true)
println("Prior probability the printer power button is on = " + answerWithNoEvidence)
}
def step2() {
printResultSummary.observe('poor)
val answerIfPrintResultPoor = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given a poor result = " + answerIfPrintResultPoor)
}
def step3() {
printResultSummary.observe('none)
val answerIfPrintResultNone = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given empty result = " + answerIfPrintResultNone)
}
def step4() {
printResultSummary.unobserve()
printerState.observe('out)
val answerIfPrinterStateOut = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given " + "out printer state = " + answerIfPrinterStateOut)
printResultSummary.observe('none)
val answerIfPrinterStateOutAndResultNone = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given out printer state and empty result = " + answerIfPrinterStateOutAndResultNone)
}
def step5() {
printResultSummary.unobserve()
printerState.unobserve()
val printerStateGoodPrior = VariableElimination.probability(printerState, 'good)
println("Prior probability the printer state is good = " + printerStateGoodPrior)
tonerLowIndicatorOn.observe(true)
val printerStateGoodGivenTonerLowIndicatorOn = VariableElimination.probability(printerState, 'good)
println("Probability printer state is good given low toner indicator = " + printerStateGoodGivenTonerLowIndicatorOn)
}
def step6() {
tonerLowIndicatorOn.unobserve()
val softwareStateCorrectPrior = VariableElimination.probability(softwareState, 'correct)
println("Prior probability the software state is correct = " + softwareStateCorrectPrior)
networkState.observe('up)
val softwareStateCorrectGivenNetworkUp = VariableElimination.probability(softwareState, 'correct)
println("Probability software state is correct given network up = " + softwareStateCorrectGivenNetworkUp)
}
def step7() {
networkState.unobserve()
printsQuickly.observe(false)
val softwareStateCorrectGivenPrintsSlowly = VariableElimination.probability(softwareState, 'correct)
println("Probability software state is correct given prints slowly = " + softwareStateCorrectGivenPrintsSlowly)
networkState.observe('up)
val softwareStateCorrectGivenPrintsSlowlyAndNetworkUp = VariableElimination.probability(softwareState, 'correct)
println("Probability software state is correct given prints slowly and network up = " + softwareStateCorrectGivenPrintsSlowlyAndNetworkUp)
}
def main(args: Array[String]) {
step1()
step2()
step3()
step4()
step5()
step6()
step7()
}
}
Prior probability the printer power button is on = 0.95
Probability the printer power button is on given a poor result = 1.0
Probability the printer power button is on given empty result = 0.8692071435134426
Probability the printer power button is on given out printer state = 0.6551724137931032
Probability the printer power button is on given out printer state and empty result = 0.6551724137931032
Prior probability the printer state is good = 0.39899999999999997
Probability printer state is good given low toner indicator = 0.23398328690807801
Prior probability the software state is correct = 0.8
Probability software state is correct given network up = 0.7999999999999999
Probability software state is correct given prints slowly = 0.6594360086767895
Probability software state is correct given prints slowly and network up = 0.5517241379310345