Methods and systems for automatically controlling aircraft takeoff rolls. A material comprising the biphenyl derivative or a polymer comprising recurring units of the biphenyl derivative is spin coated and heat treated to form a resist bottom layer having improved properties, optimum values of n and k, step coverage, etch resistance, heat resistance, solvent resistance, and minimized outgassing. Each spread spectrum sequence corresponds to a sum of at least two contributions mutually shifted by a time substantially less than the duration of a symbol, each contribution being the product of a version of one of the n input sequences times the spreading code. After decryption, packets may be reclassified as corresponding to a second predetermined application by a second classifier operating at a second portion of a network stack of the device above the first portion.