SRI DAML Project Intent of Work for 2003
Grit Denker, Patrick Lincoln, and Richard Waldinger
Artificial Intelligence Center
Menlo Park, California
Jerry R. Hobbs
Information Sciences Institute
Marina del Rey, California
In our work on the DAML project in 2003, we plan to continue with our leading roles in the development of several key ontologies, as well as techniques for doing inference with ontologies, especially within the context of the DAML experiment. We will complete and release an editing tool that we have developed for defining and instantiating ontologies in DAML+OIL, and will provide support for users. In addition, in connection with our ARDA-funded AQUAINT project, we will pursue a new objective of investigating the use of natural language queries in accessing knowledge expressed in DAML.
Ontology Development and Inference
The success of the Semantic Web depends upon the development of fundamental ontologies of very general, widely reusable domains, such as time, space, geography, processes and services, and security, privacy and trust; and the development of reasoning techniques that operate over these ontologies. We will continue our work in each of these areas.
1. Semantic Web Services. Work on DAML for Services (DAML-S), in which we have had a leading role, and in collaboration with other members of the DAML-S Coalition (DAML researchers from BBN, CMU, Nokia, SRI, Stanford, and Yale), was ongoing throughout 2002, and has been productive and fruitful. In the latter half of 2002, we have been active in the formation and initial activities of the new joint Semantic Web Services Consortium (SWSC). In the coming year, we plan to continue with our contributions to these efforts in at least the following ways:
· As co-chair of the SWSC language committee (David Martin), organize regular committee telecons, maintain the public Web site and mailing lists for the committee, and coordinate the activities required for making steady progress and releasing new versions at appropriate times.
· If the DAML-S Coalition continues as a separate body (this has not yet been decided), continue to organize regular DAML-S Coalition telecons, maintain the DAML-S section of daml.org, and coordinate the activities required for progress towards Coalition goals.
· Contribute to the technical development of the service profile, process, and grounding specification languages, and the supporting ontologies for time and resources. We expect to be especially active in the work on process modeling, service grounding, time, and resources, as we have been heretofore. In particular, we expect to accomplish further generalization of the grounding specification, and make additional progress towards the resolution of important challenges for the process model (e.g., defining the role of a rules language, and incorporating exceptions and transactions).
· Contribute to the development of use cases for Semantic Web Services, and their specification in a way that makes clear the real-world benefits of this technology, and the critical technical requirements that must be met to achieve those benefits.
· Contribute to the development of tool specifications (such as canonical data models and APIs) for Semantic Web Services technologies, and work with appropriate parties towards the provision of tools that will facilitate the adoption of this work.
· Stay abreast of work on commercial Web services standards and tools, and reach out to that community with our ideas about how to bring semantically rich service descriptions onto the Semantic Web. Monitor W3C Web services activities (in particular, the Web Services Architecture Working Group and the Web Services Description Working Group), and make sure the Architecture Working Group is aware of the potential contributions of DAML-S and its descendants.
· Participate in the DAML Experiment, by providing markup and online implementations of particular services that support the selected scenarios. This will be done in collaboration with other Coalition participants.
· Work with interested third parties to sustain interest in DAML-S, and get it into use.
An appropriate metric for measuring progress in this area is the number of users, sites, and projects that adopt DAML-S for describing their services.
2. Time. We have led in the development of DAML-Time, an ontology of time for the Semantic Web. So far it covers topological relations, durations, and the clock and calendar. We have involved other researchers in this effort, including ones at the University of Rochester, Teknowledge, Cycorp, Yale, and the University of Western Florida. This core part of the ontology is now complete. In 2003 we will extend it to cover temporal granularity, temporal aggregates, and deictic time. We will also build up resources, useful both for the DAML Experiment and more generally, including detailed ontologies of time zones and hours of operation. We will also bring more institutions into the DAML-Time effort, both in North America and Europe..
3. Space. We will organize a group for developing an ontology of space -- DAML-Space. We want to bring into this group researchers working on modeling space from a variety of perspectives, from those concerned with geographical and geological ontologies to those working in areas such as the biological sciences which are mostly concerned with the topological properties of space. We anticipate that the development of DAML-Space will parallel the development of DAML-Time, in that the areas to be covered are the topological relations (touch, overlap, etc.), measures of length, area, and volume, an ontology of latitudes and longitudes, an ontology of political divisions. In addition, the three-dimensional character of space also will lead us to develop ontologies of orientation and shape.
4. Geography Ontology and Inference. We have developed a basic geographical ontology and theory in first-order logic capable of accessing and utilizing information from a variety of agents, including the Alexandria Digital Library Gazetteer, TerraVision, the CIA World Factbook, Teknowledge's ASCS, and Landsat and GDACC satellite data repositories. Using axiomatic characterizations of these agents’ capabilities, in conjunction with SNARK's procedural-attachment mechanism and the OAA agent library, the combined theory is capable of finding answers that must be inferred from more than one of these sources because no one source has the entire answer.
We plan to extend and flesh out this line of work. We would also like to make this accessible to DAML queries, by providing a DQL (DAML Query Language) front end and, as the DAML family of languages becomes more expressive, by translation into DAML itself.
Work in this area is yielding synergistic benefits with SRI's ARDA-sponsored AQUAINT project and NASA Intelligent Systems project, and with SRI's Terravision system. We will be able to use the results of this research in the DAML experiment in connection with various applications operating in the geography domain.
5. Security, Privacy, and Trust: Given the increased importance of the World Wide Web for the military, business, industry, finance, education, government and other sectors, security will play a vital role in the success of the Semantic Web. It is essential that we have tools and techniques in place that will enable us to store, manipulate, and process the information on the Semantic Web in ways that meet security requirements such as authentication, authorization, and data integrity, among others. We have proposed a preliminary core security ontology that enables us to mark-up access control restrictions and data integrity of web pages.
In cooperation with Tim Finin, University of Maryland, Baltimore, we will develop a security ontology for delegation and access control. Security mark-up is not meaningful by itself; rather, it is made meaningful by Web applications that implement the various security techniques to protect information exchanged in transactions. Security ties in with Web services; therefore, we will coordinate our work on security with that of the DAML-S coalition and the new joint consortium on services. Starting with the interest from the last PI meeting, we will lead the effort to form a coalition to get broad support and use for the security ontology and trust logic.
As an application scenario, we will model security-releated issues of scenarios from the DAML Experiment. For this purpose, we will coordinate with John Flynn and Mike Dean to receive the necessary details on access control policy requirements in the Experiment. This is an area where it would help us to team with a military partner for instantiating the ontology for particular sites, because of security issues.
Our overall goal is to develop ontologies and supporting logics that systems to model practical security policies and to decide access control requests according to the needs of particular instantiations.
6. Translation between DAML Language and Logic. A translator has been developed between the DAML+OIL Language and the SRI theorem prover SNARK. The translation is via the Specware system of the Kestrel Institute and a Specware formulation of the DAML+OIL axioms. This formulation has enabled us to use SNARK to discover inconsistencies, redundancies, and simplifications in the DAML axioms. During the next year, we will extend this to OWL, to the DAML Query Language (DQL), and to a DAML syntax for logic. This extension will enable us to use existing SNARK theories (e.g., for geography) to answer questions which require inference and access to procedurally attached agents, such as the Alexandria Digital Library Gazetteer. We will also be able to diagnose the forthcoming OWL axioms for inconsistencies and other flaws.
DAML+OIL Plug-in for Protégé-2000
We have implemented a tool that allows the user to read, manipulate, and write DAML+OIL ontologies using Protégé-2000. We chose Protégé-2000 for its user-friendly and adaptable interface, its open-source license and good developer support, and its wide acceptance among knowledge engineers in research and practice. The current version of the plug-in parses DAML+OIL specifications (without instances) using the Jena API parser and transforms the triple model into Protégé-2000 frames. Using user-definable Protégé-2000 forms, we designed a GUI to appropriately represent all DAML+OIL specific constructs (such as restrictions, logical definitions, and class or property inheritance). We have pre-released an initial version of the DAML plug-in for Protégé-2000. We recently made the software and a user guide available at http://www.ai.sri.com/daml/DAML+OIL-plugin.
We will finish the implementation of the DAML+OIL plug-in and extend its functionality to handle instances and the main XML datatypes. This will also allow for the specification of restrictions that require instances (such as “one of” and “hasValue”). We will take feedback from users into consideration in further enhancing the functionality of the tool. The online documentation will be frequently updated with the latest versions of the plug-in and detailed user guidance on how to use it. We will make the source code available through the Protégé-2000 Web site, and will create a developer’s guide to support future implementation efforts. We expect that future extensions or changes to the plug-in -- for example, to support the latest version of OWL -- will be greatly facilitated by providing this material to the public.
We will use our tool to create core ontologies for the DAML Experiment. In particular, we expect this tool to be instrumental in advancing our research and supporting other groups in the tasks of creating core ontologies and populating them with instances in the application areas such as the Foreign Clearance Guide, DAML services, and security.
Natural Language Interface for the Semantic Web
In conjunction with our ARDA-funded AQUAINT project, and in collaboration with the DAML team at Teknowledge, we plan to investigate the use of DAML-expressed knowledge (as one of several varied knowledge sources) in the context of a natural-language question-answering system. Gemini, a powerful NL parser developed at SRI, provides translation from natural language into logic; software developed at Teknowledge and the University of Rochester translates from logic into DAML; and the ASCS system at Teknowledge supports triples-based queries of the content of the DAML-based Semantic Web. It seems natural to combine them and develop a knowledge-query tool that provides natural language access into the world of DAML. SNARK, SRI's first-order-logic theorem prover, will provide ontology translation and reasoning services in support of this effort. Additional information about this effort is available at our AQUAINT project page: http://www.ai.sri.com/aquaint.
For a project like DAML, whose primary mission is to have an impact on the world, the most appropriate measure is the number of users of the ontologies and tools we develop. Good results on controlled experiments mean nothing if no one is using DAML. Our goal will be to make the DAML+OIL Protégé plug-in widely available and to support its use, in an effort to maximize its use in the DAML community. Similarly, the number of users of the services, temporal, spatial, geographical, and security ontologies is the most appropriate metric of their success. An intermediate metric for ontologies is the number of teams that are involved in their development, since wide acceptance and use is promoted by early buy-in. An intermediate metric for the tools we develop is how well they integrate with other tools and contribute to an overall task (for example, in the DAML experiment), since easy integration promotes wide use.