. >> sreenivasan: for sean meallin, the ability to both talk to, and understand his guide dog simba is crucial. >> find the stairs. >> sreenivasan: a graduate student in the university's computer science department, meallin lost his eyesight early in life. >> lets go up stairs, good boy, >> sreenivasan: guide dogs are trained to stay calm in all situations, and without the ability to see simba's body language, meallin says it can be hard to recognize his dog's emotional state. if they're distressed emotionally or actually in physical pain, a lot of time they won't show that. >> what is is it someone with a guide dog would do on a daily basis that would be assisted by computers? >> i envision having a mechanism in the handle that vibrates when he's feeling upset about something. so maybe we're walking down the street and there's a dog loose two blocks ahead of us and simba sees this but has no way of saying that to me. so by getting a representation he's stressed out about something up ahead, i can actually decide before we get there to find another path around. so i might not be actual