Cohesion and Learning in a Tutorial Spoken Dialog System

Stems

• Stem = non-inflected
• core of a word
• Porter Stemmer
• Allows us to find ties
• between various
• inflected forms of
• the same word in adjacent turns.
• “Turns” are tutor and student contributions to Tutoring Dialogs collected by the ITSPOKE group.

Applying Cohesion measures to our Corpora: example

Turn	Contribution
Student Essay	No. The airplane and the packet have the same horizontal velocity. When the packet is dropped, the only force acting on it is g, and the net force is zero. The packet accelerates vertically down, but does not accelerate horizontally. The packet keeps moving at the same velocity while it is falling as it had when it was on the airplane. There will be displacement because the packet still moves horizontally after it is dropped. The packet will keep moving past the center of the swimming pool because of its horizontal velocity.
ITSPOKE	Uh huh. There is more still that your essay should cover. Maybe this will help you remember some of the details need in the explanation. After the packet is released, the only force acting on it is gravitational force, which acts in the vertical direction. What is the magnitude of the acceleration of the packet in the horizontal direction?
Cohesive Ties	Matches	Count
Token w/stop	packet, horizontal, the, it, is, of, only, force, acting, on, there, will, still, after	14
Token, no stop	packet, horizontal, only, force, acting, there, will, still, after	9
Stem, no stop	packet, horizont, onli, forc, act, acceler, vertic, there, will, still, after	11