Tools for DAML-Based Services, Document Templates, and Query-Answering
Intent of Work (IOW)
for April 2002 through March 2003
Sponsor: Department of the Air Force
Reference: F30602-00-0579-P00001
Prof. Richard Fikes, Principal Investigator
Dr. Deborah McGuinness, Technical Program Manager and contact
Dr. Sheila McIlraith, Web Services Technical Lead
Knowledge Systems Laboratory
Computer Science Department
Stanford University
KSL continues to play a leadership role in DAML language design and extended environment specification, committee work, and education work. This is critical to the program to provide both a sound foundation for the DAML language and the necessary supporting environment for use. In the next year KSL will provide:
· Joint US/EU ad hoc Agent Markup Language Committee participation on DAML language evolution. McGuinness and Horrocks continue their roles on the committee and Fikes joined in August and will continue in his role leading the query language development.
· KSL and Manchester representation on the World Wide Web consortium Semantic Web Activity Web Ontology working group. McGuinness and Horrocks were two of the OWL specification editors. McGuinness will provideWebOnt readouts at DAML meetings and requirements generation and coordination. She also has modeling documentation responsibilities and has served as facilitator and scribe for the requirements and goals subgroups and continues the work. The goal of this effort is to facilitate broad dissemination of a standard markup language that meets the central needs of the semantic web community.
· Authorship of the DAML Axiomatic Semantics with input from Florida (Hayes), W3C (Berners-Lee), Lucent (Patel-Schneider), and DAML community users such as Kokar, W3C’s Connolly, and BBN’s Mike Dean. Extensions will be as needed as expected from extensions such as the rule language and a default mechanism. Work also continues with SRI (Waldinger) validating the axioms.
· KSL continues its lead role in the semantic web for the military and other government briefings on the DAML and general semantic web efforts. The next semantic web day is at Intel (with McGuinness, Berners-Lee, and Hendler) and more will be supported.
· KSL and Manchester University will generate materials describing how and when to use DAML+OIL for representation and reasoning tasks. This will enable a broader community to use DAML at a more expert level.
The work provides the foundation of the DAML program providing specification of the language, specification of the core extensions such as the query language, the rule language, and the basic use cases, and the support infrastructure for communication and education.
Measures of progress are: the use of DAML both within the DAML project as well as in the outside world, the acceptance and use of the W3C web ontology language, and the use of the axioms. Some of the education and documentation will support the DAML experiment.
KSL has played a lead role in the development of Web Service markup and agent technology within the DAML program. In the next year, KSL will focus on the following three tasks.
· Relevance and Technical Goals: DAML-S (DAML Web Services Markup Language) is a DAML+OIL ontology for describing Web services (self-contained network-accessible programs and devices). It is being designed for use (predominantly) by Web service providers, in order to describe the capabilities of services in an unambiguous, computer-interpretable form. DAML-S description of a service will enable an agent (computer program) to find a service meeting its needs, to understand how to use such a service, and to understand the consequences of its use. In concert with appropriate agent technology, DAML-S will eventually enable self-describing Web services that can be discovered, invoked, composed and monitored.
· KSL (McIlraith) has played a leadership role in developing DAML-S in conjunction with a consortium of DAML contractors including SRI (Martin, Hobbs, Narayanan), CMU (Sycara, Payne), BBN (Burstein), Yale (McDermott), Nokia (Lassila), and with feedback from U. Manchester (Horrocks). In 2002-2003, we will continue to refine and extend DAML-S, to complete the services ontology and to respond to feedback from DAML-S users. Three key challenges will drive our work for this year: 1) development of a DAML-S grounding that will connect high-level service descriptions with lower-level communication descriptions in the industry-adopted WSDL; 2) development of a DAML-S messaging view; and 3) ensuring that DAML-S drives and is synchronized with fast-changing industry efforts in this area.
· The DAML-S Coalition will contribute to the collective development of a corpus of service ontologies to be used by the DAML Experiment, and by the developers of DAML Web service technology. These ontologies will service as a test bed for the DAML Experiment and for Web service applications, more generally. KSL is currently in early-stage negotiation with a major developer of network-accessible devices, for development and deployment of KSL’s DAML-enabled agent technology. There may also be an opportunity to develop DAML-S ontologies in this domain and to showcase the relevance of DAML in this domain.
· DAML Experiment: Services has been identified as one of the key DAML technologies for the DAML experiment. The continued development of DAML-S, and the construction of DAML-S ontologies is central to the DAML-S experiment.
· Measure of Technical Progress: A measure of technical progress will be the use of DAML-S within the DAML experiment and within other real-world applications domains. A second measure of technical progress will be the influence DAML-S has on the development of next-generation service markup initiatives by industry and the W3C.
· Technical goal: The correct representation of a service in DAML-S is time-consuming and challenging, even for a DAML-S literate researcher. The objective of this task is to develop a Services editor (not an ontology editor) that will facilitate the markup of web services by novice and experienced users, alike. Development of such a tool is critical to widespread use of DAML-S. We have designed and developed a prototype editor in 2001-2001. Prototype development will continue in 2002-2003.
· KSL will refine and augment their DAML-S Web Services Editor. We will integrate the new releases of DAML-S into our editor. We will integrate simulation and verification code into the editor to enable a marked-up service to be simulated and verified. This task will be done in collaboration with researchers at SRI (Narayanan, Martin, Hobbs). We hope to work with an integrator for delivery of a robust version of the editor to the DAML Experiment community.
· DAML Experiment: Services has been identified as one of the key DAML technologies for the DAML experiment. Development of a DAML-S editor will support correct and widespread use of DAML-S by DAML researchers, and make DAML-S more easily accessible to non-DARPA users.
· Measure of Technical Progress: A measure of technical progress will be the use of the DAML-S editor within the DAML experiment and within other real-world applications domains.
· Technical goal: Our goal is to develop agent technology that works in concert with DAML-S service descriptions to support user-customized Web service composition, interoperation, execution monitoring and recovery. To date KSL has developed technology for user-customized DAML-enabled Web service composition. We will augment and extend functionality in 2002.
· The focus of our work this year will be on 1) the customization of Web service interaction for individual users to incorporate more complex user constraints and preferences; and 2) development of technology for execution monitoring and error recovery.
· DAML Experiment: We anticipate that this technology will be relevant to the agent technologies being developed for the DAML Experiment. The role this technology will play in the agent technology of the DAML experiment will be clarified as more details of the DAML Experiment are established.
· Measure of Technical Progress: A measure of technical progress will be the use of this technology by the DAML experiment and by other users outside the DARPA community.
· KSL will continue its development of a methodology and supporting technology for query-answering from knowledge expressed in DAML on distributed Web sites. In addition to addressing the standard issues about how to do effective reasoning with knowledge expressed in an object-oriented representation language augmented with rules (e.g., DAML), our work will address the significant additional issues raised by the knowledge being stored as text (i.e., as markup) and by the knowledge using terminology defined in ontologies resident on (perhaps multiple) other Web sites. For example, reasoners are not going to be able to do anything significant working directly from the markup, and one doesn't want to pay the overhead of loading knowledge into a reasoner’s internal memory every time one wants to get an answer to a query.
The methodology we are developing is grounded in the use case goal of associating with a Web site containing DAML markup an agent that is an expert on the knowledge represented in the DAML markup on the pages of that Web site and that provides a set of information services based on that knowledge. We are developing an API and architecture for such agents that will support providing a query answering service using the markup on the site as its knowledge base and some or all of the content of that knowledge base in various forms such as a set of RDF statements, a KIF logical theory, an HTML document suitable for presentation on various output media, etc. We will explore the notion of extending that idea to say that the *only* thing one encounters when accessing DAML markup is such an agent, where one of the services of the agent is to provide the knowledge represented there in text as a DAML element. The agent will act like a knowledge server for the knowledge represented in DAML markup in that it will keep the content of the markup loaded and include a query answering and constraint checking service.
· The supporting technology we are developing for this task includes (1) a DAML reasoner called JTP implemented in JAVA suitable for use as a primary component in an agent that is an expert on the DAML markup on a given Web site, and (2) a query language and supporting query-answering protocol for DAML called DQL.
JTP contains a general-purpose reasoner integrated with a collection of special-purpose reasoners that are suited to DAML+OIL and can be augmented incrementally to provide expert reasoning in specific task domains. This may include collaboration with Manchester's DAML+OIL special purpose reasoner or possibly Maryland's Parka system for large-scale knowledge bases. We have successfully tested and demonstrated JTP’s ability to answer queries from small to medium sized DAML+OIL knowledge bases and have delivered an initial version of the system to the DAML integrators (BBN). During the coming year, we plan to upgrade the system to be usable with (1) larger DAML+OIL knowledge bases, (2) knowledge bases that use ontologies distributed over multiple Web sites, and (3) the anticipated extended expressive power of the full DAML language. We also plan on implementing both a human Web-based user interface that will allow JTP to be used as a query-answering agent for a DAML Web site (as described above) and a query-answering API for use by computer-based agents. Those interfaces will be implementations of the DQL query language and API.
DQL (DAML Query Language) is being developed by the DAML Joint Committee, and KSL is leading that development effort. DQL is intended to specify a standard interface for query-answering from DAML knowledge bases and will include a formally defined language for expressing queries and inferred query results. The design of an initial version of DQL by the Joint Committee will be completed in this quarter. During the remainder of this year, we will (1) implement and test the initial design, and (2) evolve the design based on feedback and on the anticipated expansion of the DAML language.
Evaluation of both DQL and JTP can be based on their ability to effectively support the query-answering capabilities that will be needed in the upcoming DAML demonstration and experiment. Evaluation results would be in terms of specific kinds of queries (perhaps specified as parameterized queries as in HPKB) asked of specific knowledge bases distributed over a specific number of sites.
The ability to automatically reason with knowledge expressed on Web pages is a central notion in the Semantic Web vision and can be expected to play a significant role in the upcoming DAML demonstration and experiment. A reasoning capability enables answers to be determined for queries from Web sites that do not explicitly state those answers. The reasoner infers the implicit answers by using the content of the Web site and of the ontologies used by the Web site. In addition, a reasoning capability can determine whether the information expressed in semantic markup on a Web site is logically consistent with the ontologies referenced by the Web site. Such reasoning is a core capability of semantic markup that distinguishes its use from the use of XML and HTML.
DQL and the reasoning technology we are developing provide the key elements of a query-answering facility that performs deductive retrieval from knowledge represented in DAML and a diagnostic facility that checks the logical consistency of such knowledge. The query-answering facility can be used by any service or tool that is retrieving information from DAML knowledge bases, and the diagnostic facility can be used by any service or tool that is supporting the authoring of ontologies and knowledge in DAML. In the upcoming DAML demonstration and experiment, we will provide JTP as a component tool and support its use as both a Web site query-answering agent and as a diagnostic tool for use in ontology development.
KSL continues its migration and customization of its ontology tool environment to the DAML Language. Additionally, KSL’s subcontractor, Manchester University, continues its DAML tool environment evolution. The main areas of emphasis are in the following areas.
· The KSL JTP reasoner is being developed and enhanced for DAML. It is largely driven by the query answering work and is elaborated on in section III. It provides a portion of the ontology development environment infrastructure. It is a hybrid reasoning architecture and may be used to incorporate other special purpose reasoners such as FACT. It is also the integration platform for some special purpose subsumption reasoners.
· KSL and colleagues continue to utilize the Chimaera Ontology Evolution Environment tool aimed at supporting ontology merging, analysis, and transition. KSL has helped merge and analyze knowledge bases deemed to be of greater importance after 9-11 and will continue to support this effort in Horus and elsewhere. KSL is in discussions with other government agencies for utilizing this infrastructure including NSF, DIA, NSA, and ARDA. Other KSL foundational infrastructure is developed and enhanced on an as-needed basis such as translator work in support of ontology merging and integration.
· Manchester University is providing a major extension of the OILED ontology editor in order to turn it into a full-fledged knowledge engineering environment for DAML+OIL. Evaluation of integration and use of OILED into the DAML-S environment will also be done.
· Manchester University will be enhancing the DAML+OIL reasoning capabilities of FACT. Discussions have begun with HP in order to consider linking FACT with HP’s Jena in order to provide a complete DAML+OIL infrastructure including such components as a parser, triple store, reasoner, etc...
Ontology development environment work is critical and leverageable by the DAML experiment. The reasoners JTP and FACT may be used to generate consequences of DAML assertions. OILED may be used to generate and browse DAML experiment ontologies and Chimaera may be used to analyze and merge DAML+OIL ontologies.
Measures of success with respect to the DAML experiment are use and use without consulting of the tools. Measures of success of the work in general is use of the tools inside and outside the DAML community.