Invitation letters for Visa requests are provided. For faster processing, please also send an email, with subject line "Visa for NAS2018" to Huiwei Wang at huiwei.wang@gmail.com. Include your name, email address, mailing address, IEEE member number (if any) and the ID of the paper you are presenting (if any). By the policy of Southwest University, we can only issue visa invitation letters to registered attendees. If you want to apply for visa, you may register earlier.