The present invention relates to an algorithm that retrieves only k data elements having the largest key values from a dataset in a time linearly proportional to the size of the dataset. An embodiment provides a system that includes an imaging device operable to capture an image depicting a member of a class of subjects that may have a temporal presence in an area. Diagnostic procedures are applied to the identified segment to determine a cause of the failure. Closely and evenly-spaced ridges that are situated in between the corrugations, add rigidity and durability to the duct.