Does knowledge of language consist of symbolic rules? How do children learn and use their linguistic knowledge? To elucidate these questions, we present a computational model that acquires phonological knowledge from a corpus of common English nouns and verbs. In…

This paper introduces a model of spatial cognition to describe the states of partial knowledge that people have about the spatial structure of a large-scale environment. Spatial knowledge has several different representations, each of which captures one aspect of the…

This paper presents a version of frames suitable for representing knowledge for a class of reconition problems. An initial section gives an intuitive model of frames, and illustrates a number of desirable features of such a representation. A more technical…

If we are provided a face database with only one example view per person, is it possible to recognize new views of them under a variety of different poses, especially views rotated in depth from the original example view? We…

This report elucidates the linguistic representation of temporal relations among events. This involves examining sentences that contain two clauses connected by words like once, by the time, when, and before. Specifically, the effect of the tenses of the connected clauses…

The Listener is an automated system that unintrusively performs knowledge acquisition from informal input. The Listener develops a coherent internal representation of a description from an initial set of disorganized, imprecise, incomplete, ambiguous, and possibly inconsistent statements. The Listener can…

The central thesis of this report is that human language is NP-complete. That is, the process of comprehending and producing utterances is bounded above by the class NP, and below by NP-hardness. This constructive complexity thesis has two empirical consequences.…

Obtaining exact depth from binocular disparities is hard if camera calibration is needed. We will show that qualitative depth information can be obtained from stereo disparities with almost no computations and with no prior knowledge (or computation) of camera parameters.…

Compliant control is a standard method for performing fine manipulation tasks, like grasping and assembly, but it requires estimation of the state of contact between the robot arm and the objects involved. Here we present a method to learn a…

Humans recognize optical reflectance properties of surfaces such as metal, plastic, or paper from a single image without knowledge of illumination. We develop a machine vision system to perform similar recognition tasks automatically. Reflectance estimation under unknown, arbitrary illumination proves…