A method for detecting smoke detector alarms comprises analyzing at least two parameters of ambient sound over a period of time to detect a temporal pattern of the alarm. A duct unit A of the present invention has upper and lower wall portions 1 and 3 and right and left wall portions 2 and 4 formed of metal sheets, and spin locks curved into a curled shape, the spin locks being provided on the wall portions 1 to 4 at two side edges of the same along the longitudinal direction. The received signal and the generated wavelets are mixed and the result integrated such that the integrated output tends to zero. In another aspect, encrypted computer data may be transferred over wired or wireless networks. Once verbs arc captured they can be analyzed for ways to improve predictive ability.