The Bio-jETI Framework - User-Level Workflow Design: A Bioinformatics Perspective - page 54

drop-down lists which the editor fills with all valid options (i.e., all concrete
and abstract services or types as defined by the interface descriptions and
the respective taxonomies).
Several of the templates that are provided by PROPHETS by default are
the result of experiences with the application of PROPHETS to the bioin-
formatics domain. As the constraint templates are defined in a simple XML
file, advanced users can easily extend the list to the needs of the specific
domain. Currently, the following templates are available (template name, de-
scription/cloze text, SLTL representation):

• service avoidance :

Avoid the service s .
G( ¬ s true )

• conditional service avoidance :

If service s 1 is used, avoid the service s 2 subsequently.
G(

s 1 true ⇒ X ( G ( ¬ s 2 true )))

• mutual exclusion of services

At most one of the services s 1 and s 2 may be used.
¬ ( F ( s 1 true ) ∧ F ( s 2 true ))

• service redundancy avoidance :

Do not use service s more than once.
G(

s true ⇒ X(G( ¬ s true )))

• service enforcement :

Enforce the use of service s .
F(

s true )

•

conditional service enforcement :
If service s 1 is used, enforce the use of service s 2 subsequently.
G( s 1 true ⇒ X ( F ( s 2 true )))

• service succession :

If service s 1 is used, service s 2 has to be used next.
G( s 1 true ⇒ X( s 2 true ))

• service dependency :

Service s 1 depends on service s 2 (i.e., service s 1 canonlybeusedafter
s 2 ).
¬

s 1 true WU s 2 true

• final service

Use service s as last service in the solution.
F( s true ) ∧ G ( ¬ ( s true ) ∨¬ ( true ))

• type avoidance :

Avoid the type t .
G( ¬ t )

• type enforcement :

Enforce the existence of type t .
F( t )