SWSL Committee Work Plan
(v. 1.0)
----------- Major Tasks ----------- (1) Identify requirements for Web service description language(s). 1.1 Identify functional and non-functional requirements Our present list includes the following functionality: Functional requirements: a. advertising and discovery b. matchmaking c. negotiation and contracting d. composition e. execution monitoring We expect that the language will enable various kinds of reasoning, e.g., with rules and ontologies, in support of requirements (a)-(e). Non-functional requirements: a. security b. trust c. authentication etc. 1.2 Analyze requirements identified by the SWSA committee and align with own requirements 1.3 Develop use cases for requirements identified In this task, we consider requirements and use cases generated by both the architecture and language committees. REMARKS: a. Currently our understanding of the requirements leads us to the view that our main contribution will be the development of a logic-based model for semantic Web services (SWSLM). Once this is done, we will propose an XML-based surface language that maps into the aforesaid model. This language is what the programs will use to describe and reason about the services. To support widespread deployment of services described using this logic-based model, we expect to provide mappings into concrete Web service standards, such as WSDL and BPEL4WS. To support semantic modeling and analysis of existing Web services handcrafted using Web service standards, we also expect to provide reverse mappings from (selected subsets of) these standards into the logic-based model. We realize that several different surface languages can be developed and fully expect that other groups might create a language that is more suitable to them. However, the languages will have the same semantics grounded in SWSLM. b. The outcome of the work on the aforesaid three subareas of SWSLM will be designed to support the requirements set forth in (1) c. SWSLM must support the requirements developed by the SWSA committee. In particular, SWSLM should support the high-level protocols developed by the SWSA. It will be mainly the job of SWSA to represent the components of the SWS architecture using the SWSL's language. This process will require interaction between the two committees, which will likely result in the various refinements to both the architecture and the language. MILESTONES for Task #1: - Preparing the requirements document. - Preparing use cases DELIVERABLES (Mid Nov 2003): i. A requirements document (in the style of a white paper). ii. A use case document (2) Specification of a formal service model for semantic Web services 2.1. Development of key abstractions and of a conceptual model for the formal service model. REMARK: This refers to "meta-modeling" rather than modeling in a concrete language -- first we have to agree what we would like to be able to express in the formal service model. This task involves a number subtasks including: a. Identify properties of the process model(s) matching requirements from the requirements analysis. b. Clarify whether the operational semantics of services is of concern to SWSL or is already covered by Web service standards. We should make a clear distinction between operational semantics (the execution model) and conceptualization (the ontological process model) c. Identify layers of expressiveness. For instance: - Basic layer for discovery - Advanced layers for reasoning - Constraints vs. executable specification d. Identify different dimensions required for the semantic modeling of services. For instance: - Data dimensions -> parameters - The functional dimension - The actor dimension - Distribution dimension e. Identify the key components of a formal service model and their relationships. - sublanguage for process modeling - sublanguage for constraints - sublanguage for ontology specification - ... 2.2 Categorize existing models under discussion (PSL, <I-N-C-A>, DAML-S' profile ontology, UML, RuleML, F-logic, DAML-S' process ontology, Concurrent Transaction Logic, BPEL4WS, Golog, Pi-calculus) using the conceptual model developed in 2.1. Relate the different models with respect to expressiveness, for defining multiple language levels later. Assess these languages with respect to the underlying paradigm (logic-based, imperative, object-oriented, rule-based, constraint-based) and the compatibility of paradigms. 2.3. Specify the formal model of SWS. This model will include a formal language (the "abstract syntax") with a formal semantics. This subtask will involve: - Selecting from the existing models suitable ones to match the required properties. - Merging, unifying, specialization/generalization of existing models. - Specifying the relationships among the chosen models and providing a formal semantics. 2.4. Develop an XML encoding of the formal language in 2.3 in XML. 2.5. Demonstrate the usage of the model(s) by modeling the use cases from the requirements analysis. REMARK: 2.1 - 2.4 could undergo multiple design cycles as for example analysis of existing models could uncover concepts found in service models that would become a key abstraction. MILESTONES for Task #2: - Conceptual model of the formal service model (end of 1/2004) - Categorization of existing approaches (end of 2/2004) - Specification of formal service model(s) (end of 5/2004) - Modeling of use cases using the conceptual model (end of 7/2004) DELIVERABLES: i. Specification of the conceptual model (End of Jan 2004) ii. Specification of a formal model containing (June 2004) - Formal specification of the "abstract syntax" and semantics - Formal specification of an XML encoding of the abstract syntax - Rationale / issues document iii. Tutorials, overviews, etc. (Sept 2004) - Technical overview - Reference guide - Walk-through / Tutorial - Examples, Use Cases (3) Establish the relationship to Web Service Standards and Semantic Web standards a. Provide a specification of the mapping to existing Web service standards, such as: - WSDL/UDDI/BPEL4WS - Grounding, Implementation Layer b. Provide a specification of the relationship to existing Semantic Web standards such as: - RDF - OWL MILESTONES for Task #3: - Specification of mapping to Web service standards - Specification of relationship to Semantic Web standards DELIVERABLES: i. Specification of an XML encoding of the formal model (July 2004) ii. Specification of the use of the language with other Web standards (Oct 2004) (4) Exploring techniques for implementing and applying parts of the languages. For example, techniques for inferencing with service descriptions. MILESTONES for task #4: - Producing report on implementation techniques DELIVERABLE: a. Report on implementation and reasoning techniques (5) Dissemination a. Communication with W3C b. Feedback to scientific and industrial community MILESTONES for Task #5: - Submission of W3C document DELIVERABLES: i. Submission of input document to W3C or some other appropriate venue. (January 2005) ii. Publications in forums such as WWW Conference, ICWI, etc. (on continuing basis) ------------------------- Summary of the Milestones ------------------------- Task 1: i. Preparing the requirements document. ii. Preparing use cases Task 2: i. Conceptual model of the services: End of Jan 2004 ii. Categorization of existing approaches: End of Feb 2004 iii. Specification of formal service model(s): End of May 2004 iv. Modeling of use cases using the formal service model: End of July 2003 Task 3: i. Specification of mapping to Web service standards ii. Specification of relationship to Semantic Web standards iii. Specification of an XML-based encoding Task 4: i. Producing report on implementation techniques Task 5: i. Submission of W3C document --------------------------- Summary of the Deliverables --------------------------- Task 1: i. Requirements document and use cases: Mid Nov 2003. ii. Use cases: Mid Nov 2003. Task 2: i. Specification of a conceptual model: End of Jan 2004. ii. Specification of a formal model: June 2004. iii. Tutorials and other aids: Sept 2004. Task 3: i. Specification of the XML-based surface language and of a mapping of the language to the formal model: July 2004. ii. Specification of the use of the language with other Web standards: Oct. 2004. Task 4: i. Report on implementation techniques: January 2005. Task 5: i. Submission of input document to W3C or other venue: January 2005. ii. Publications in forums such as WWW Conference, ICWI, etc.: On continuing basis ----------------------- Measurements of success ----------------------- 1. Timely production of deliverables 2. Uptake by other researchers - Substantive use in research projects - Mentions in publications - Contributions of use cases, examples, tools 3. Uptake by industry 4. Adoption as basis for standardization effort at W3C (or other appropriate venue)SWSL Committee Home Page