1. 16/11/2003 1 Semantic Web Services Language Requirements Presenter: Emilia Cimpian http://www.daml.org/services/swsl/requirements/

2. 16/11/2003 2 Overview of Topics Introduction Formalization (General Requirements) Functional Requirements

3. 16/11/2003 3 Introduction SWSI Language Committee – to develop computer language technology that will provide a firm, long-term foundation for the future of Web services on the Internet – formal language that allows for rich declarative specification of a wide variety of information about Web services – starting point – OWL-S

4. 16/11/2003 4 Introduction Requirements (SWSL): – Formalization – Functional

5. 16/11/2003 5 General Requirements General Language Properties Expressive Power Meta Properties

6. 16/11/2003 6 General Requirements - General Language Properties - Declarative semantics Compositional Extensible

7. 16/11/2003 7 General Requirements - Expressive Power - Interface description Functional & behavioral specification on component software Simple workflow description Incomplete service specification Constraints & temporal constraints satisfaction Exceptions Plans and planning domains Scheduling Policies Hypothetical scenarios Composition of sub-activities

8. 16/11/2003 8 General Requirements - Meta Properties - Understandable Easy to be written by a broad range of practitioners Possibility of integration Address aspects of the web services Interoperable with automated reasoning techniques Extendable annotation mechanism

9. 16/11/2003 9 General Requirements - Meta Properties - Capable of: – Linking the remote service specifications – Supporting analyses – Interoperating with programs that can execute a process model – Multi-party activities across organizational boundaries – Lifecycle management and process control – Specification of taxonomies of services and service descriptions – Importing external ontologies

10. 16/11/2003 10 Functional Requirements Advertising and Matching Negotiation and Contracting Process Modeling Process Enactment

11. 16/11/2003 11 Functional Requirements - Advertising and Matching - The language must support: – Description of the functionality of the core component service Knowledge state Data interfaces – Description of a wide range of characteristics – Relaxation of certain properties – Definition of service request – Ordering, ranking and filtering of matches

12. 16/11/2003 12 Functional Requirements - Advertising and Matching - The definition of service description must consider issues like scale and distributed discovery No assumption should be made on the architecture of discovery services that utilize or mediate service descriptions and service requests One must be able to determine how a service request relates to matching service descriptions “No Eyeballs Always Required” Consistency between advertise service descriptions and their process descriptions

13. 16/11/2003 13 Functional Requirements - Advertising and Matching - Objectives: – Possibility to identify cases where service descriptions deviate a valid representation of the service – Sufficient accessible information for a human intervention – Easy for people to read, write and understand service descriptions

14. 16/11/2003 14 Functional Requirements - Contracting and Negotiation - The language must support – Wide variety of attributes/aspects of a deal – Committed/proposed contractual agreements – Partial/complete contracts or contract proposals – Representation of business partner qualification – Communication between contracting parties – Modification of proposed/committed deals – Execution of contract provisions – Monitoring of execution of committed deals – Hypothetical reasoning about the contract/proposal

15. 16/11/2003 15 Functional Requirements - Contracting and Negotiation - Objectives – Complement development of standard/common ontologies for frequently needed contract characteristics – Complement other emerging standard efforts – Should seek to represent commitments in such a way as to mesh well all methods of dispute resolution and recourse – Should seek to be compatible with the contract aspects of the existing industry standards for web services

16. 16/11/2003 16 Functional Requirements - Process Modeling - Ordering and temporal constraints State constraints Resource constraints Composition

17. 16/11/2003 17 Functional Requirements - Process Modeling - Objectives – Compatibility with existing process modeling standards – Support mappings from existing process modeling software tools.

18. 16/11/2003 18 Functional Requirements - Enactment - Describe and allow for the invocation of services via service endpoints Recognize and handle exceptions Constraint checking Security aspects Policy aspects "Make it so" elements to link to the environment Dealing with the status of services, resource levels, epistemic states of actors Logging, metering, billing, auditing, notification

19. 16/11/2003 19 Functional Requirements - Enactment - Services metrics, Quality of Service guarantees Dispute Resolution and Compliance Explanation Health checks and debugging aids Redundancy and Robustness Resource allocation and load balancing Allowance for dynamic runtime aspects of discovery, composition and negotiation of services on-the-fly Version update while services are live

20. 16/11/2003 20 Functional Requirements - Enactment - Objectives – complement well other emerging standards efforts relevant to enactment and execution – significant enhancement to existing or emerging web service enactment protocols