OWA

Version:1.0
Provider:URV
SOAP service’s name:
 OWA-URV (see SOAP requests for details)

Description

The Ordered Weighted Averaging operators, commonly called OWA operators, provide a parameterized class of mean type aggregation operators. OWA was defined by R.R. Yager in 1988. Here we provide an implementation of the OWA operator. The main characteristic of this aggregation operator is the fact that the weights are associated to the values instead to criteria. In this way, we can define different aggregation policies according to the importance that we associate to high and low performance scores.

Contact: Aida Valls <aida.valls@urv.cat>, Jordi Canals <jordi.canals@estudiants.urv.cat>

Reference:
R.R. Yager, On Ordered Weighted Averaging Aggregation, IEEE Transactions on Systems, Man and Cybernetics, 18, pp. 119-145 (1988)

Inputs

(For outputs, see below)

alternatives

A list of alternatives. Alternatives can be activated or desactivated via the <active> tag (true or false). By default (no <active> tag), alternatives are considered as active.

The input value should be a valid XMCDA document whose main tag is <alternatives>. It must have the following form:

<alternatives>
    <alternative>
        <active>[...]</active>
        [...]
    </alternative>
    [...]
</alternatives>

criteria

A list of criteria. Criteria are always active.

The input value should be a valid XMCDA document whose main tag is <criteria>. It must have the following form:

<criteria>
    <criterion>
        <active>[...]</active>
        [...]
    </criterion>
    [...]
</criteria>

weights

The weights are associated to the values of the alteranatives. Assuming that the values on the alternative will be sorted from the best to the worst (e.g. 7, 5, 5, 3, 1), the list of weights must be ordered according to the importance that is given to the values, from the highest to the lowest. For example a list of weights as (0.5, 0.5, 0, 0, 0) is ignoring the 3 lowest values, and making an average of the two highest ones. A list like (0, 0, 1, 0 ,0 ) is calculating the median, while (0, 0, 0, 0, 1) is taking the minimum. Notice that the sum of weights is required to be 1.

The input value should be a valid XMCDA document whose main tag is <alternativesValues>. It must have the following form:

<alternativesValues>
  <alternativeValue>
        <values>
                <value>
                        <real>[...]</real>
                </value>
                <value>
                        <integer>[...]</integer>
                </value>
                [...]
  </alternativeValue>
</alternativesValues>

performanceTable

The performance table will contain only numerical values, all in the same scale of measurement.

The input value should be a valid XMCDA document whose main tag is <performanceTable>. It must have the following form:

<performanceTable>
        <alternativePerformances>
                <alternativeID>[...]</alternativeID>
                <performance>
                        <criterionID>[...]</criterionID>
                        <value>
                                <real>[...]</real>
                        </value>
                </performance>
                [...]
        </alternativePerformances>
        [...]
</performanceTable>

Outputs

alternativesValues

Result obtained from the OWA aggregation on each alternative.

The returned value is a XMCDA document whose main tag is <alternativesValues>.


messages

A status message.

The returned value is a XMCDA document whose main tag is <methodMessages>.


Original xml description