Formal Definition
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Preliminaries
- – a set of all the possible value names,
- – a value name,
- – a set of all the possible feature names,
- – a feature name,
- – a feature set,
- – feature/value relation, a set of ordered pairs, i.e. a binary relation between and .
Example:
- F1 = {lang,type} – a feature set containing two feature names lang and type,
- V1 = {(lang,en),(lang,de),(type,text / plain) - feature/value relation contianig three ordered pairs.
Profile
A profile is a tuple describing some input/output data for a web service:
- – profile features, a feature set of data features,
- – profile feature/value map , a function from profile features to their values representing input data.
Example:
Input
A web service input is a tuple
- input features a set of features that must be present in the input of a web service,
- input feature/value relation a relation representing possible values of the input features of a web service,
- user specifiable input features features that a user may specify,
- input selected feature/value map a total function mapping each input feature to its selected value.
Example:
- ,
- ,
- ,
- VIS = {(lang,en),(type,text / plain)}.
Output
A web service output is a tuple
- output features a feature set representing an output of a web service,
- output feature/value relation a relation representing possible values of the output features of a web service,
- output selected feature/value map a total function mapping each output feature to its selected value.
- input dependence map , where , such that maps input feature/value pair to a set of dependent output feature/value pairs.
- new - a web service output does not include its input, i.e. .
Example:
- ,
- ,
- VOS = {(lang,en),(type,text / html)},
- ,
- new1 = true.
Service
A web service chaining description is a tuple .
- input I a web service input,
- output O a web service output.
Chaining Requirements
- required input features ,
- matching profile values .
Example:
- ,
- .
Match Function
A match function from a set of all the possible web service/profile tuples into zero or one. If the value is one then profile describes a possible input of web service . M is defined as follows:
Example:
Profile describes a possible input of service where:
- ,
because:
- , i.e. , and
- , i.e. , and
- the output is new i.e new1 = true.
Specialisation Function
A specialisation function . E is defined as follows:
such that:
- , where:
- ,
- ,
and
- , where:
- ,
- ,
- ,