quired) ReceptionistT.onDuty TeleSvcDsk.online G: TeleSvcDsk.authentication_successful, G: PatientT.registeredByAssister, latientT.unilaterally_authenticated ReceptionistT.assistedRegistrationComplete TeleSvcDsk.registrationComplete pas(authenticateeT -> Patient T pcrs (reg assister -> ReceptionistT, assisted caller authenticatorT -> TeleSvcDsk) : UTPA ->PatientT, assistiing registrar -> TeleSvcDsk) aidedRegistration PDP4_Rulel: T: ! (AuthenticationOK, TeleSvcDsk, Patient T) C: PatientT is a Patient of Doctor, and PatientTAuthenticatedbyTeleSvcDsk, PatientT.AssistanceNotNeeded, TeleSvcDsk.online prs(registrar -> TeleSvcDsk, G: Patient T.registered, Registeree -> PatientT) : registration TeleSvcDsk.RegistrationComplete PDP5_Rulel: PDP5_Rule1: T: ! (RegistrationOK, TeleSvcDsk, PatientT) T: ! (RegistrationOK, TeleSvcDsk, ReceptionistT) C: PatientT is a Patient of Doctor and C: PatientT is a Patient of Doctor and PatientTAuthenticatedByTeleSvcDsk, PatientTAuthenticatedbyTeleSvcDsk, TeleSvcDsk.online, TeleSvcDsk.online, DoctorT.AvailableForConsultation, DoctorT.AvailableForConsultation, Patient T.registered and Patient T.registered and PatientT.authenticated PatientT.authenticated G: TeleSvcDsk.svcAccessed, G: TeleSvcDsk.svcAccessed, DoctorT.consultationComplete, DoctorT.consultationComplete, PatientT.consulted PatientT.consultated pcd (consult administrator -> TeleSvcDsk, consultant -> DoctorT, consulter -> Patient T : consultation Figure 5.26 Global PESM for the tele-consultation service, with authentication added. 5.8 Discussion and Related Work The collaboration-oriented approach presented in this chapter builds on the work on composing services presented in Sanders [2] and Sanders et al. [21]. The global PESM diagrams used in our approach are similar to the choreographies inspired by Service Delivery Platforms UML 2.x activities presented in Castejón and Brak [22] and further elaborated in Castejón et al. [23]. However, those choreographies describe static/nondynamic composition of collaborations, for which the c