Defining details for decay curves

Define decay curve details for equipment. The decay curve records the anticipated asset condition score over time for a given asset class.

Use Markov chains if you want the system to determine the decay curve for you. Markov chains use a transition matrix to determine the likelihood that the equipment will be in a certain state or health after it has reached a certain state or health in a previous iteration of the chain. The changes to the state of the equipment are called transitions and the probabilities that the equipment moves from one state to another are called transition probabilities. The initial state of the equipment is assumed to be perfect health.

  1. Select Equipment > Equipment Ranking > Decay Curves.
  2. Click New Record.
  3. Specify this information:
    Decay Curve
    Specify the name and description of the decay curve.
    Organization
    Specify the organization associated with the decay curve.
    Status
    Specify the status of the decay curve.
    Type Max
    Specify the maximum value for the number of periods, usage or percentage related to the selection you made for the Type field.
    Type
    Specify Period Based, Usage Based, or Percentage as the decay curve type.
    Period Based
    If you specify the Type as Period Based, specify a unit of measure for the period of time.
    Usage Based
    If you specify the Type as Usage Based, specify of unit of measure for usage.
    Condition Score Start
    Specify the starting condition score value when the equipment is new
    Condition Score End
    Specify the starting condition score value when the equipment is at the end of its useful life.
    Condition Score Threshold
    Specify the threshold condition score when the equipment reaches the end of its useful life.
    Operational Modifier
    Optionally, specify the operational modifier for the decay curve.

    The operational modifier notes usage conditions such as cold climate and school year on which the Decay Curve is based. Usage in warmer climate and for a whole year could result in different decay curves.

    Linear Asset Flag
    Optionally, select this check box to indicate that the decay curve relates to linear assets.
  4. Specify this information for stochastic modeling:
    Markov Chains
    Select this check box to use Markov chains to create the decay curve.
    Number of States
    Specify the number of states that will be used in the transition matrix. The minimum is 2 and the maximum is 10.
    Curve Point Interval
    Specify the interval for curve points. The interval depends on your selection of Type and Type Max.

    If you are defining a period-based curve for 20 years and you want a condition score for every year, specify 1. The system will then calculate curve points for you and divide 20 by 1.

    For a usage-based decay curve where the maximum usage is 500,000 miles you may want a condition score for every 10,000 miles. In this example, specify 10,000 for the Curve Point Interval and then the system will set curve points at 50.

    Precision
    Set the precision of the calculated condition score.
  5. Click Save.