8 research outputs found
Machine learning research 1989-90
Multifunctional knowledge bases offer a significant advance in artificial intelligence because they can support numerous expert tasks within a domain. As a result they amortize the costs of building a knowledge base over multiple expert systems and they reduce the brittleness of each system. Due to the inevitable size and complexity of multifunctional knowledge bases, their construction and maintenance require knowledge engineering and acquisition tools that can automatically identify interactions between new and existing knowledge. Furthermore, their use requires software for accessing those portions of the knowledge base that coherently answer questions. Considerable progress was made in developing software for building and accessing multifunctional knowledge bases. A language was developed for representing knowledge, along with software tools for editing and displaying knowledge, a machine learning program for integrating new information into existing knowledge, and a question answering system for accessing the knowledge base
Improving the explanation capabilities of advisory systems
A major limitation of current advisory systems (e.g., intelligent tutoring systems and expert systems) is their restricted ability to give explanations. The goal of our research is to develop and evaluate a flexible explanation facility, one that can dynamically generate responses to questions not anticipated by the system's designers and that can tailor these responses to individual users. To achieve this flexibility, we are developing a large knowledge base, a viewpoint construction facility, and a modeling facility. In the long term we plan to build and evaluate advisory systems with flexible explanation facilities for scientists in numerous domains. In the short term, we are focusing on a single complex domain in biological science, and we are working toward two important milestones: (1) building and evaluating an advisory system with a flexible explanation facility for freshman-level students studying biology, and (2) developing general methods and tools for building similar explanation facilities in other domains
Generating referring expressions in a domain of objects and processes
This thesis presents a collection of algorithms and data structures for the generation of
pronouns, anaphoric definite noun phrases, and one-anaphoric phrases. After a close
analysis of the particular kinds of referring expressions that appear in a particular
domain -that of cookery recipes -the thesis presents an appropriate ontology and a
corresponding representation language. This ontology is then integrated into a wider
framework for language generation as a whole, whereupon we show how the representation language can be successfully used to produce appropriate referring expressions for
a range of complex object types.Amongst the more important ideas explored in the thesis are the following:• We introduce the notion of a generalized physical object as a way of representing
singular entities, mass entities, and entities which are sets.• We adopt the view that planning operators are essentially underspecified events,
and use this, in conjunction with a simple model of the hearer, to allow us to
determine the appropriate level of detail at which a given plan should be described.• We make use of a discourse model that distinguishes local and global focus, and
is closely tied to a notion of discourse structure; and we introduce a notion of
DISCRIMINATORY POWER as a means to choosing the content of a referring expression.• We present a model of the generation of referring expressions that makes use of
two levels of intermediate representation, and integrate this model with the use
of a linguistically- founded grammar for noun phrases.The thesis ends by making some suggestions for further extensions to the work reported
here
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Planning multisentential English text using communicative acts
The goal of this research is to develop explanation presentation mechanisms for knowledge based
systems which enable them to define domain terminology and concepts, narrate events, elucidate plans,
processes, or propositions and argue to support a claim or advocate action. This requires the development
of devices which select, structure, order and then linguistically realize explanation content as coherent and
cohesive English text.
With the goal of identifying generic explanation presentation strategies, a wide range of naturally
occurring texts were analyzed with respect to their communicative sttucture, function, content and intended
effects on the reader. This motivated an integrated theory of communicative acts which characterizes text at
the level of rhetorical acts (e.g., describe, define, narrate), illocutionary acts (e.g., inform, request), and
locutionary acts (e.g., ask, command). Taken as a whole, the identified communicative acts characterize
the structure, content and intended effects of four types of text: description, narration, exposition,
argument. These text types have distinct effects such as getting the reader to know about entities, to know
about events, to understand plans, processes, or propositions, or to believe propositions or want to
perform actions. In addition to identifying the communicative function and effect of text at multiple levels
of abstraction, this dissertation details a tripartite theory of focus of attention (discourse focus, temporal
focus, and spatial focus) which constrains the planning and linguistic realization of text.
To test the integrated theory of communicative acts and tripartite theory of focus of attention, a text
generation system TEXPLAN (Textual EXplanation PLANner) was implemented that plans and
linguistically realizes multisentential and multiparagraph explanations from knowledge based systems. The
communicative acts identified during text analysis were formalized as over sixty compositional and (in
some cases) recursive plan operators in the library of a hierarchical planner. Discourse, temporal, and
spatial focus models were implemented to track and use attentional information to guide the organization
and realization of text. Because the plan operators distinguish between the communicative function (e.g.,
argue for a proposition) and the expected effect (e.g., the reader believes the proposition) of communicative
acts, the system is able to construct a discourse model of the structure and function of its textual responses
as well as a user model of the expected effects of its responses on the reader's knowledge, beliefs, and
desires. The system uses both the discourse model and user model to guide subsequent utterances. To test
its generality, the system was interfaced to a variety of domain applications including a neuropsychological
diagnosis system, a mission planning system, and a knowledge based mission simulator. The system
produces descriptions, narrations, expositions, and arguments from these applications, thus exhibiting a
broader range of rhetorical coverage than previous text generation systems
Proceedings of the 1993 Conference on Intelligent Computer-Aided Training and Virtual Environment Technology
The volume 2 proceedings from the 1993 Conference on Intelligent Computer-Aided Training and Virtual Environment Technology are presented. Topics discussed include intelligent computer assisted training (ICAT) systems architectures, ICAT educational and medical applications, virtual environment (VE) training and assessment, human factors engineering and VE, ICAT theory and natural language processing, ICAT military applications, VE engineering applications, ICAT knowledge acquisition processes and applications, and ICAT aerospace applications
Seventh Annual Workshop on Space Operations Applications and Research (SOAR 1993), volume 1
This document contains papers presented at the Space Operations, Applications and Research Symposium (SOAR) Symposium hosted by NASA/Johnson Space Center (JSC) on August 3-5, 1993, and held at JSC Gilruth Recreation Center. SOAR included NASA and USAF programmatic overview, plenary session, panel discussions, panel sessions, and exhibits. It invited technical papers in support of U.S. Army, U.S. Navy, Department of Energy, NASA, and USAF programs in the following areas: robotics and telepresence, automation and intelligent systems, human factors, life support, and space maintenance and servicing. SOAR was concerned with Government-sponsored research and development relevant to aerospace operations. More than 100 technical papers, 17 exhibits, a plenary session, several panel discussions, and several keynote speeches were included in SOAR '93
THE ROLE OF PERSPECTIVE IN RESPONDING TO PROPERTY MISCONCEPTIONS'
In order to adequately respond to misconceptions involving an object's properties, we must have a context-sensitive method for determining object similarity. Such a method is introduced here. Some of the necessary contextual information is captured by a new notion of object perspective. It is shown how object perspective can be used to account for different responses to a given misconception in different contexts. 1