Henssen 2008 - QoS attributes

Capturing and Using QoS Relationships to Improve Service Selection

Promotes the use of MCDA (multi-criteria decision Analysis

• important to analyze weights related to criteria + weights related to interactions between criteria
  
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Dealing with Quality Tradeoffs during Service Selection

aggregation approaches for integrating weights into the service selection procedure for a QoS:

1. compensatory [29][30]: they amount to being substitution rates. The priorities for different criteria to be expressed on the same scale
   
2. noncompensatory [4, 8, 21, 31]: weights are simply a measure of relative importance of the criteria involved. They are only used to indicate the relative importance
   

Promotes the use of outranking methods for defining global priority constraints

outranking relation is a binary relation S on the set of potential choices A such that aiSaj to decide that ai is at least as good as aj.

Pj(a, b) = Fj[dj(a, b)] for all a, b
dj(a, b) = gj(a) - gj(b)

where gj(a) is the score of service a over quality of service a

There are six categories of functions for F

1. immediate preference
2. indifference threshold
3. increases continuously until reaching the indifference threshold
4. comprises an indifference and a preference threshold
5. increases continuously between an indifference and a preference threshold
6. Gaussian law with a fixed standard deviation

• aggregating the preferences
• wj is the preference for characteristic j
  

• outranking flows
• The positive outranking flow expresses how an alternative a is outrankking all the others (n-1 alternatives)
  
• The negative outranking flow indicates how an alternative a is outranked by other n-1 alternatives

complete ranking of PROMETHEE method is derived using the following formula

The paper is clumsy when it comes to their real experiment. values are drawn from no where and it is not clear how these values are calculated. The author needs prior knowledge and there is a lack of proper description