kmi.open.ac.uk Semantic Execution Environments Service Engineering and Execution Barry Norton and Mick Kerrigan

kmi.open.ac.uk Plan for the Day Review and reinforcement of WSMO model for services and Semantic SOA Reference Ontology Semantic Execution Environment (SEE) Reference Architecture Semantic Web Service Engineering Scenarios Web Service Modelling Toolkit (WSMT) Hands-on with SEE and WSMT The Future for Service Engineering 1

kmi.open.ac.uk Plan for the Day Review and reinforcement of WSMO model for services and Semantic SOA Reference Ontology Semantic Execution Environment (SEE) Reference Architecture Semantic Web Service Engineering Scenarios Web Service Modelling Toolkit (WSMT) Hands-on with SEE and WSMT The Future for Service Engineering 2

kmi.open.ac.uk Web Service Description WSMO Web Services describe abilities of deployed services… Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules Web Service 3

kmi.open.ac.uk Web Service Description Their Capabilities describe their functional abilities… Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules Web Service 4

kmi.open.ac.uk Web Service Description Preconditions express guarantees they expect from clients, purely over information they communicate… Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules Web Service 5

kmi.open.ac.uk Web Service Description Assumptions express general guarantees they expect of clients, involving the environment outside communications… Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules Web Service 6

kmi.open.ac.uk Web Service Description Postconditions express guarantees they make over information communicated back, providing the preconditions and assumptions are met by the client… Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules Web Service 7

kmi.open.ac.uk Web Service Description Effects express the general guarantees made, outside information directly communicated, providing the preconditions and assumptions are met by the client Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules Web Service 8

kmi.open.ac.uk Web Service Description The interfaces of web services describe their behavioural characteristics, i.e. the communications they engage in Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 9

kmi.open.ac.uk Web Service Description The choreography expresses communications the service engages in with its clients… Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 10

kmi.open.ac.uk Web Service Description The state signature describes these communications semantically, by linking modes to ontological concepts Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 11

kmi.open.ac.uk Web Service Description The state signature describes these communications semantically, by linking modes to ontological concepts: –IN modes describe communications the service is able to receive Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 12

kmi.open.ac.uk Web Service Description The state signature describes these communications semantically, by linking modes to ontological concepts: –IN modes describe communications the client would like to receive; –OUT modes describe communications the service is able to send Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 13

kmi.open.ac.uk Web Service Description The state signature describes these communications semantically, by linking modes to ontological concepts: –IN modes describe communications the client would like to receive; –OUT modes describe communications the service is able to send; –modes may be grounded to physical communications, most usually WSDL messages but also REST resource methods, and in the IRS LISP and Java functions. Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 14

kmi.open.ac.uk Web Service Description Transition rules link communications into a stateful interaction Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 15

kmi.open.ac.uk Web Service Description Transition rules link communications into a stateful interaction: –Transition rules may be used in matching and (process) mediation against goals, Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 16

kmi.open.ac.uk Web Service Description Transition rules link communications into a stateful interaction: –Transition rules may be used in matching and (process) mediation against goals, or for –In process mediation between IRS-III/WSMX broker and the deployed service Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 17

kmi.open.ac.uk Web Service Description Orchestrations describe how composite services achieve their behaviour in terms of communications between its components, which may be goals or services, together with mediators. Capability Interface Choreography Orchestration State Signature Transition Rules Web Service Precondition Assumption Postcondition Effect 18

kmi.open.ac.uk Goal Description Goals describe requirements from client perspective… Goal Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules State Signature Transition Rules 19

kmi.open.ac.uk Goal Description Their Capabilities describe the functional requirements… Goal Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules State Signature Transition Rules 20

kmi.open.ac.uk Goal Description Preconditions express guarantees client can make, purely over information they can communicate, in order that functional requirements are met… Goal Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules State Signature Transition Rules 21

kmi.open.ac.uk Goal Description Assumptions express general guarantees client can make, involving the environment, in order that functional requirements are met… Goal Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules State Signature Transition Rules 22

kmi.open.ac.uk Goal Description Postconditions express guarantees client would like over information communicated back in order that functional requirements are met… Goal Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules State Signature Transition Rules 23

kmi.open.ac.uk Goal Description Effects express the general guarantees the client would like after the goal has been achieved Goal Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules State Signature Transition Rules 24

kmi.open.ac.uk Goal Description Capabilities can be used for one or more of: representing a client- oriented perspective, advertising and service discovery. Goal Capability Interface Precondition Assumption Postcondition Effect Choreography Orchestration State Signature Transition Rules State Signature Transition Rules 25

kmi.open.ac.uk Goal Description The interfaces of goals describe the behavioural requirements of clients, i.e. constraints over communication Goal Capability Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules Precondition Assumption Postcondition Effect 26

kmi.open.ac.uk Goal Description The choreography expresses communications the client is able to engage in… Goal Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules Capability Precondition Assumption Postcondition Effect 27

kmi.open.ac.uk Goal Description Goal Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules The state signature describes these communications semantically, by linking modes to ontological concepts Capability Precondition Assumption Postcondition Effect 28

kmi.open.ac.uk Goal Description The state signature describes these communications semantically, by linking modes to ontological concepts: –IN modes describe communications the client would like to receive Goal Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules Capability Precondition Assumption Postcondition Effect 29

kmi.open.ac.uk Goal Description The state signature describes these communications semantically, by linking modes to ontological concepts: –IN modes describe communications the client would like to receive; –OUT modes describe communications the client is able to send. Goal Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules Capability Precondition Assumption Postcondition Effect 30

kmi.open.ac.uk Goal Description Goal Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules Transition rules link communications into a stateful interaction Capability Precondition Assumption Postcondition Effect 31

kmi.open.ac.uk Goal Description Goal Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules Transition rules link communications into a stateful interaction: –Transition rules can be used to constrain the stateful behaviour of matching services, or be used in process mediation should the goal be linked to a service which is not directly behaviourally compatible. Capability Precondition Assumption Postcondition Effect 32

kmi.open.ac.uk Goal Description Goal Interface Choreography Orchestration State Signature Transition Rules State Signature Transition Rules Orchestrations govern over the composite behaviour that is required to go into meeting the goal – the technology to exploit this is not yet available Capability Precondition Assumption Postcondition Effect 33

kmi.open.ac.uk Web Service Description WG-Mediators describe which goals are met by a web service WG-Mediator Mediation Service OO-Mediator 34 Mediation Goal

kmi.open.ac.uk Web Service Description WG-Mediators describe which goals are met by a web service; the descriptions may have some mismatch to be mediated 35 WG-Mediator Mediation Service OO-Mediator Mediation Goal

kmi.open.ac.uk Web Service Description WG-Mediators describe which goals are met by a web service; the descriptions may have some mismatch to be mediated: –an oo-mediator may be supported by mapping rules between dissimilar ontologies 36 WG-Mediator Mediation Service OO-Mediator Mediation Goal

kmi.open.ac.uk Web Service Description WG-Mediators describe which goals are met by a web service; the descriptions may have some mismatch to be mediated: –an oo-mediator may be supported by mapping rules between dissimilar ontologies; –a mediation service identifies a web service capable of resolving the mismatch 37 WG-Mediator Mediation Service OO-Mediator Mediation Goal

kmi.open.ac.uk Web Service Description WG-Mediators describe which goals are met by a web service; the descriptions may have some mismatch to be mediated: –an oo-mediator may be supported by mapping rules between dissimilar ontologies; –a mediation service identifies a web service capable of resolving the mismatch; –a mediation goal describes the capability of resolving the mismatch without identifying a web service (in which case discovery might be recursively applied) 38 WG-Mediator Mediation Service OO-Mediator Mediation Goal

kmi.open.ac.uk Plan for the Day Review and reinforcement of WSMO model for services and Semantic SOA Reference Ontology Semantic Execution Environment (SEE) Reference Architecture Semantic Web Service Engineering Scenarios Web Service Modelling Toolkit (WSMT) Hands-on with SEE and WSMT The Future for Service Engineering 39

kmi.open.ac.uk WSMO, WSML and WSMX Conceptual Model for SWS Ontology & Rule Language for the Semantic Web with built-in support for WSMO Semantic Execution Environment 40

kmi.open.ac.uk WSMO, WSML and SEE Conceptual Model for SWS Ontology & Rule Languages Semantic Execution Environments OWL, OCML, SWRL etc. 41

kmi.open.ac.uk WSMO, WSML and SEE Conceptual Model for SWS Ontology & Rule Languages Semantic Execution Environments and independent broker services OWL, OCML, SWRL etc. 42 Glue 2

kmi.open.ac.uk Semantic Execution (Developing) Standards Conceptual Model for SWS Ontology & Rule Language for the Semantic Web with built-in support for WSMO Semantic SOA Reference Ontology SEE Reference Architecture 43 Glue 2 Semantic Execution Environments and independent broker services

kmi.open.ac.uk Semantic SOA Reference Ontology Objectives that a client wants to achieve Formally specified terminology used by all other components Semantic description of Services, which advertise and allow access to capabilities: - Capability description (functional description of capability) - Interfaces (usage via service) Connectors between components with mediation facilities for handling heterogeneities SOA Reference Model Aligned with 44

kmi.open.ac.uk WSDL/SOAP Web Services Web Service Web Service WSDL Describes Service Service Consumer Finds Services UDDI Registry UDDI Registry Points to Description Points to Service Communicate with XML Messages SOAP 45

kmi.open.ac.uk Semantic Web Services Web Service Web Service Communicate with XML Messages SOAP 46 WSDL Describes Service Semantic Web Service Semantic Web Service Service Consumer Semantic Goal Semantic Goal Describes Requirements Semantic Execution Environment Semantic Execution Environment SWS Registry SWS Registry Published to

kmi.open.ac.uk Service Oriented Architecture 47 Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Custom Application Custom Application

kmi.open.ac.uk Semantically Enabled SOA 48 Semantic Execution Environment Discovery Ranking & Selection Ranking & Selection Composition Mediation Grounding & Invocation Grounding & Invocation Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Web Service Goal

kmi.open.ac.uk SEE Reference Architecture 49

kmi.open.ac.uk SEE Reference Architecture 50 Base services, providing storage and reasoning support, underlie all broker services

kmi.open.ac.uk SEE Reference Architecture 51 Vertical services are invoked by both base and broker services Their purpose is orthogonal to the individual purposes of the other services

kmi.open.ac.uk SEE Reference Architecture 52 Broker services are otherwise independent and atomic behaviours expected of a SEE

kmi.open.ac.uk SEE Reference Architecture 53 Composite services may also be formed over these broker services to meet requester-oriented needs

kmi.open.ac.uk 54 Reference Architecture Base Services Storage: ‘create/retrieve/update/delete’ (CRUD) operations on: ontological definitions; goal descriptions; service descriptions; mediator descriptions; mapping documents. Reasoning: Accepts logical expressions as queries and assertions over both ontological definitions and service-related descriptions.

kmi.open.ac.uk 55 Reference Architecture Vertical Services Monitoring: Each core SEE service is associated with concepts in an events ontology When invoked, services may raise events of the appropriate concepts at various points during the behaviour, such as: commencement; completion; exceptional conditions.

kmi.open.ac.uk 56 Reference Architecture Broker Services Discovery: Concerns finding services that meet a given goal. Ranking: Involves ordering candidate services according to how well they meet a goal. Selection: Provides automated means by which candidate services may be discounted

kmi.open.ac.uk 57 Discovery Find Semantic Web Services that can totally or partial fulfil the end users Goal Goal Description Goal Description Discovery Service Discovery Service SWS Registry SWS Registry Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description

kmi.open.ac.uk 58 Discovery G WS Exact Match WS G Plug-in Match G WS Subsumption Match G WS Intersection Match GWS No Match

kmi.open.ac.uk 59 Ranking Ordering candidate Web Services according to the match to the goal A particularly useful form of ranking is based on non-functional requirements Goal Description Goal Description Ranking Service Ranking Service Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description 1

kmi.open.ac.uk Quality of Service Aspects 16 ontologies have been recommended for modeling WSMO Non-functional aspects of Web services 60 Locative Ontology Locative Ontology Temporal Ontology Temporal Ontology Availability Ontology Availability Ontology Obligation Ontology Obligation Ontology Price Ontology Price Ontology Payment Ontology Payment Ontology Discounts Ontology Discounts Ontology Rights Ontology Rights Ontology Trust Ontology Trust Ontology Quality of Service Ontology Quality of Service Ontology Security Ontology Security Ontology Intellectual Property Ontology Intellectual Property Ontology Rewards Ontology Rewards Ontology Provider Ontology Provider Ontology Measures Ontology Measures Ontology Currency Ontology Currency Ontology

kmi.open.ac.uk 61 Selection Choosing, or narrowing the choice among, the most appropriate Web Service(s) to the goal This may simply be based on ranking but may also take into account instance data where the goal is generic Goal Description Goal Description Selection Service Selection Service Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Instance Data

kmi.open.ac.uk 62 Reference Architecture Broker Services Composition: Concerns forming an orchestrated service to meet a given goal. Data Mediation: Transforms instances from a representation in one ontology to another. Process Mediation: Creates an executable process model that resolves inconsistencies between two otherwise incompatible processes.

kmi.open.ac.uk 63 Composition Combine a number of Semantic Web Services together to fulfil the end users Goal Goal Description Goal Description Composition Service Composition Service Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Web Service Description Composite Web Service Description Composite Web Service Description

kmi.open.ac.uk Composition Composed Web Service descriptions advertise services that are realized through the execution of other services Orchestration specifies how to invoke these other services to fulfill the advertised functionality 64 Web Service

kmi.open.ac.uk 65 Data Mediation Data Mediation in general concerns resolving terminological mismatches and enabling interoperability at the data level via: –Ontology Merging –Ontology Alignment –Instance Transformation As a service data mediation effects the latter of these aspects Data Mediation Service Data Mediation Service Web Service Description Web Service Description Web Service Description Web Service Description Ontology Instances Web Service Description Web Service Description Web Service Description Web Service Description Ontology Instances

kmi.open.ac.uk 66 Process Mediation Process Mediation for resolving communication mismatches, establishing behavioural compatibility and allowing interoperability at the process level

kmi.open.ac.uk 67 Reference Architecture Broker Services Process Execution: Involves interpreting a process model and, at each step, producing the conceptual communications produced or allowed. Lifting & Lowering: Respectively: Produces the conceptual representation of a web service communication (for instance a SOAP message); Produces a web service communication corresponding to its conceptual representation.

kmi.open.ac.uk 68 Reference Architecture Composite Services At an internal level broker services are composed to form services such as: Choreography-based execution: Given a goal and a service description: if the choreographies are directly compatible then the service choreography is executed; if there exist mismatches then process mediation is applied and the resulting process is executed. Orchestration-driven execution: Given a service description with an orchestration:

kmi.open.ac.uk 69 Reference Architecture Composite Services At an internal level broker services are composed to form services such as: Choreography-based execution Orchestration-driven execution: Given a service description with an orchestration: any contained goals are resolved using discovery, ranking and selection; the choreographies of all component services are folded into the orchestration to form a single process; this process is executed.

kmi.open.ac.uk 70 Reference Architecture Composite Services At an internal level broker services are composed to form services such as: Choreography-based execution Orchestration-driven execution Goal-driven execution: Given a goal description: if it can be resolved to a service using discovery, ranking and selection then this service is executed according to choreography-based execution or orchestration-driven execution if it cannot composition may be applied and the resulting composite service executed according to orchestration-driven execution.