SWSL Committee Work Plan
(v. 1.0)
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Major Tasks
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(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)
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Summary of the Milestones
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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
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Summary of the Deliverables
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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
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Measurements of success
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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)
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