Abstract: A context-aware method for answering a question about a video includes: receiving the question about the video that is paused at a pausing position; obtaining and analyzing context information at the pausing position of the video, the context information including supplementary materials of the video; and automatically searching an answer to the question based on the context information at the pausing position of the video.

Abstract: Echo locating apparatus for a vision-impaired person which includes: a sound emitter for emitting a stream of sound bursts of ultrahigh frequency; at least one receive channel having a microphone for receiving echoes of the sound bursts and generating echo signals; an echo profile detector for generating an echo profile signal of each echo signal; a delay circuit for adding a variable delay to the echo profile signal, wherein the variable delay increases with the distance to the reflecting at a diminishing rate of increase. The sound burst emitter is preferably arranged to emit a beam of sound bursts having a given beam angle that can be pointed in any direction.