FLOWERY BRANCH — Atlanta Falcons coach Mike Smith has put a strong emphasis since the start of training camp on improving the team’s run defense. Smith sees incremental improvement, but stops well short of saying the Falcons have cured the ills that made them the NFL’s second-worst unit against the run last season. For Atlanta to succeed, Smith and his staff are putting major responsibility on second-year inside linebackers Paul Worrilow and Joplo Bartu, a pair of undrafted college free agents last year who emerged as starters and finished as the leading and third-leading tacklers.