Learning Coherent Concepts: Theory and Applications to Natural Language

Supported by NSF

Period: 1999-2002

This research seeks to develop an integrated view - theoretical understanding, algorithms development and experimental evaluation - for learning coherent concepts. These are learning scenarios that are common in cognitive learning - where multiple learners co-exist and may learn different functions on the same input, but there are mutual compatibility constraints on their outcomes. Our effort will consist of developing a learning theory for these situations and of studying algorithmic ways to exploit them in natural language inferences.

The theoretical study will concentrate on developing a semantics for the coherency conditions and study it from a learning theory point of view. The goal is to understand in what ways does learning become easier and more robust in these situations. The algorithmic study will concentrate on developing ways to exploit coherency and will have a significant experimental component, using the problem of shallow parsing as a testbed for investigating chaining of coherent classifiers and inferences that rely on the outcomes of several classifiers.

This research would have a significant impact on theoretical research in learning and on our ability to perform higher level inference in natural language. First, it would help to resolve the contrast between the predicted hardness of learning and the apparent ease at which cognitive systems learn. Moreover will provide an understanding of how to exploit coherency in order to develop better learning and inference methods for these situations and would result in an integrated learning approach to a variety of shallow parsing tasks, implemented and demonstrated in a large scale manner using the SNoW learning architecture. Finally, incorporating the understanding of interacting classifiers as well as methods to perform inferences that rely on several classifiers into our learning system would be directly applicable to a variety of other tasks in this domain.

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