Each scheme is meant to formulate an activation area for a target word w i either by local set operations on unimodal activation areas (from text and image-derived data) or by global algebraic operations on normalized unimodal semantic similarity scores.
the local fusion scheme selects for each target w i two unimodal neighborhoods of a small fixed size (e.g., 100 neighbors) and then performs set operations (e.g., union, intersection) on these neighborhoods to obtain a crossmodal activation area.