Tools for DAML-Based Services, Document Templates, and Query-Answering
Intent of Work (IOW) for April 2001 through March 2002
Sponsor: Department of the Air Force
Reference: F30602-00-0579-P00001
Prof. Richard Fikes, Principal Investigator
Dr. Deborah McGuinness, Technical Program Manager
Knowledge Systems Laboratory
Computer Science Department
Stanford University
- DAML Language Development
KSL continues to play a leadership role in its DAML language and committee work. In the next year KSL will provide:
- Joint US/EU ad hoc Agent Markup Language Committee participation on language evolution. Other than weekly phone conference call participation, this includes contributions and analysis of the DAML language package (such as the walk-thru co-edited by McGuinness, the language description, Chimaera analysis of the DAML, etc.). This is joint work with W3C (Berners-Lee, Connolly, Brickley), BBN (Dean, Barber), Amsterdam (van Harmelen, Fensel), Florida (Hayes), Maryland (Heflin, Hendler), Manchester (Horrocks), Nokia (Lassila), Lucent (Patel-Schneider), Olin (Stein), and Stanford (Decker).
- Authorship of the DAML Axiomatic Semantics with input from Florida (Hayes), W3C (Berners-Lee), Lucent (Patel-Schneider), and DAML community users such as Kokar. Extensions will be provided for the XML data types for DAML concrete domains and the DAML rule language.
- Rule Language work. This arose out of a joint paper with Nokia (Lassila) on rule languages for the web and also out of chairing the DAML language committee at the last PI meeting. Follow-up collaborations have begun with MIT (Grosoff), Manchester (Horrocks), and Lucent (Patel-Schneider).
- Anticipated co-chair (with co-chair Hendler) for the web semantics language committee of the W3C under Eric Miller’s W3C web activity. Also expected collaboration with Nokia (Lassila is the expected committee scribe).
Our hope is that the next step after the W3C committee is formed will be to follow a path similar to that used for the dissemination of HTML and XML. The central goal is to obtain widespread adoption of the language as the standard markup language for the Semantic Web with a user community similar to the current XML user community.
DAML-Enabled Web Services
KSL also continues to play a leadership role in DAML Web Service markup and agent technology development. In the next year, KSL will focus on the following tasks.
DAML Web Services Markup Language (DAML-S)
KSL and SRI (Hobbs, Martin, Narayan) are playing a leadership role in developing a DAML Web Services Markup Language (DAML-S) in conjunction with a consortium of other DAML Web service contractors including CMU (Sycara, Payne), BBN (Burstein), Nokia (Lassila), and with feedback from Booz Allen (Neighbors, Chi). In 2002, we will continue to refine and extend DAML-S in response to feedback from developers marking up Web services with DAML-S. We will extend the language for our specific needs in support of Web service composition, execution monitoring, and recovery. We also anticipate augmenting DAML-S in order to markup (mobile) devices as Web services. Some of these language extensions may be performed in collaboration with Nokia, Booz Allen, and SRI.
KSL will contribute to the collective development of a corpus of annotated Web services to be used by developers of DAML Web service technology as a test bed for their Web service applications. Our contribution will include the markup of services in the travel domain we have been working with over the last year, as well as in another domain that will present significant challenges to Web service automation. Three domains we are currently examining are university services applications, mobile services applications, and financial services applications. There may also be an opportunity to develop service markup in a Cisco Systems domain.
DAML-S is being designed for use by Web service providers to describe the capabilities of their services in semantic markup. The DAML-S description of a service will enable the service to be found by agents seeking such services, and will enable agents who are considering use of a service to determine the requirements for using the service, the results produced by the service, and the protocol for using the service.
DAML-S Web Service Annotation Tool
KSL will design and develop prototype components for a DAML-S Web service annotation tool. This tool will be used by service providers to describe the capabilities of their services in DAML-S. It will facilitate the markup of both new and existing Web services. KSL will work with Booz Allen (Chi, Neighbors) to realize the full development and testing of this tool.
Web Service Composition, Interoperation, Execution Monitoring, and Recovery
KSL will continue its development of technology for DAML-enabled Web service composition and interoperation. This technology will be used by Web service users and Web service providers alike to automatically compose Web services and achieve Web service interoperation. A focus of our work this year will be on the maximal exploitation and showcasing of DAML-S, and on the customization of Web service interaction for individual users. We will extend our technology to address the problem of Web service execution monitoring and error recovery. We will test our technology on the corpus of DAML-S annotated Web services developed by different DAML-S users (including but not limited to SRI, CMU, BBN, Booz Allen) to confirm our ability to interoperate seamlessly. We will also test our technology on service applications we are developing predominantly at KSL.
Reasoning With Knowledge Represented In DAML
KSL will develop a methodology and supporting technology for reasoning with 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 develop will be based on the idea of associating with a Web page containing DAML markup an agent that is an expert on the knowledge represented in the DAML markup on the page and that provides a set of information services based on that knowledge. We will develop an API and architecture for such agents that will support providing a query answering service using the markup on the page 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 would act like a knowledge server for the knowledge represented in DAML markup in that it could keep the content of the markup loaded or in a quickly loadable form and include a query answering and constraint checking service.
- The supporting technology we will develop for this task will include 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 page. JTP will contain 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.
The ability to automatically reason with knowledge expressed on Web pages is a central notion in the Semantic Web vision. 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.
The reasoning technology we are developing will provide 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 markup, and the diagnostic facility can be used by any service or tool that is supporting the authoring of semantic markup. We will illustrate these potential uses by developing the query-answering agent described above for Web sites containing DAML markup and by exploiting the consistency checking reasoning in our Chimaera ontology development environment described below.
Ontology Development Environment
KSL continues its migration and customization of its ontology tool environment to the DAML Language. The main areas of emphasis are in the following areas.
- Translator work has already helped diagnose DAML language flaws and DAML ontology library submission integrity checks. Our translator work continues with the DAML language evolution so that DAML (RDF and XML) can be integrated with OKBC- and KIF-compliant languages. We have started collaborating with Nokia (Lassila) and Manchester (Horrocks, Bechhofer) on translator work so that our systems can better interoperate.
- Ontology analysis and merging work has helped identify some RDF and DAML bugs in DAML ontologies. We are working on evolving our environment into a lighter weight ontology analysis and merging tool. We will also continue to diagnose and merge DAML library ontologies. For example, we have begun discussions with bio-informatics researchers at Manchester and SMI regarding use of our tools to help their evolution problems with their large ontologies, and with NCAR (National Center for Atmospheric Research) regarding use of our tools for analyzing large geo-science ontologies.
- Joint work with Manchester (Horrocks, Bechhofer) will begin to integrate their DAML+OIL editor/browser into the KSL environment, thereby minimizing the dependence on heavier systems such as Ontolingua.
- We have begun work on a lightweight DAML+OIL classifier that will be used both to do a quick classification of new descriptions and to quickly and simply determine where a new object description belongs. An initial application is to quickly determine what "marketing bucket" a buyer fits into based on a simple description of the buyer and buying event. This work has just begun, but our goal is to provide JAVA applets for distribution and use. We will also integrate it into our JTP hybrid reasoning environment.
The intended audience for the full translator and the deep ontology environment tools are the owners of ontologies. This is a small group of specialized people like database schema owners. The lightweight tools however are aimed at the masses. The lightweight tools attempt to simulate a "Microsoft FrontPage"-like tool that allows the masses to generate syntactically valid HTML (and then analyze and maintain it from a semantic perspective). Interest in both the lightweight and heavyweight tools has been voiced from large companies such as Cisco and Daimler Chrysler, startup companies, small companies such as VerticalNet, and academic and government entities.