23 Decision Module

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Decision Module

<moduleDescriptor id="DecisionModule">
	<description>DecisionModule</description>
	<className>nl.wldelft.fews.system.plugin.decisionmodule.DecisionModule</className>
</moduleDescriptor>

Overview

The Decision Module in Delft-FEWS is used to implement decision logic and evaluation for barriers. With this module we can iteratively evaluate configurated decision rules. The configuration file of the Decision Module contains the definition of one or more Decision Trees. These Decision Trees defined in the Decision Module are associated with a Barrier definition which are defined by the Barriers configuration file.

Some important prerequisites:

1. The decision logic (criteria) is linked to the barrier state. Barrier states could be for example "the barrier is open", "the barrier is closed", "the barrier is halfway closed or halfway opened", "at a stage where some additional criteria need to be evaluated", etc. For each of these states, separate decision logic may be relevant and should be evaluated.
2. While evaluating the decision logic, relevant input may consist of information from both the present and future model state.

Some examples to illustrate the above:

• When the barrier is open, and when the forecast results show that water levels at location A will exceed 3 meters, the barrier should start closing when the water level at the barrier passes the 2 meter mark.
• When the barrier is closed, the barrier should be opened when the local water level gradient is negative.

1. Furthermore, the decision logic should be "scalable" (i.e. it should be easy to add additional rules). If we continue with the above example, a decision rule could also be

• When the barrier is open, and when the forecast results show that water levels at location A will exceed 3 meters, the barrier should close. If the river discharge at location C is below 6000 m3/s, the barrier should start closing when the local water level passes the 2 meter mark. If the river discharge at location C exceeds the 6000 m3/s, the barrier should start closing at slack tide. The barrier is only allowed to close when the shipping through the location B has been blocked in advance.

Contents

Configuration

Variables definition

All variables within the Decision Module are time series in the form of Time Series Sets. Within the Decision Module various items make use of a variableId. This variableId is used in the actual section as an alias to that time series.
The identifier assigned to a time series should contain alphanumeric characters only. It should not start with a numerical character.

variableId

required element used to identify the time series in the decisionModule block or in the rules block.

timeSeriesSet

required element used to identify the timeSerieSet.

	<variable>
		<variableId>SVKW.position.in</variableId>
		<timeSeriesSet>
			<moduleInstanceId>RMM_Structures_Forecast_Processing_Extrapolate</moduleInstanceId>
			<valueType>scalar</valueType>
			<parameterId>State.position.meting</parameterId>
			<locationId>SVKW</locationId>
			<timeSeriesType>simulated forecasting</timeSeriesType>
			<timeStep unit="minute" multiplier="10"/>
			<relativeViewPeriod unit="day" start="0" end="1" endOverrulable="true"/>
			<readWriteMode>add originals</readWriteMode>
		</timeSeriesSet>
	</variable>
	<variable>
		<variableId>SVKW.position.dss</variableId>
		<timeSeriesSet>
			<moduleInstanceId>RMM_DecisionTree</moduleInstanceId>
			<valueType>scalar</valueType>
			<parameterId>State.position.meting</parameterId>
			<locationId>SVKW</locationId>
			<timeSeriesType>simulated forecasting</timeSeriesType>
			<timeStep unit="minute" multiplier="10"/>
			<relativeViewPeriod unit="day" start="0" end="1" endOverrulable="true"/>
			<readWriteMode>add originals</readWriteMode>
		</timeSeriesSet>
	</variable>

Schema definition

Rules definition

The Rules section defines the rules which will be used by the decision entries of each decisionTree.

variables

This section contain a set of variables defined only for the rule definitions. For a description of the variables see the section above.

criticalConditions

The criticalConditions determine if further activity should be realized. The evaluation period for the criticalCondions is determined by the definition in the decisionModule (evaluation = lastKnownState).

The definition of the criticalConditions reuses the criticalConditionLoopUp of the Lookup Table Module.

transitionRules

If certain criticalConditions are met, at a certain moment the state transition should be activated. The moment at which this occurs will be determined by the transitionRules.

Schema definition