Abstract: A method, in a data processing system, of imposing constraints on data files which are changed by update statements, includes the steps of: a) identifying a particular object of the update O.sub.x and a particular attribute being updated; b) finding an applicable constraint based on the particular attribute being updated; c) converting the particular update object O.sub.x to at least one other object which is in the applicable constraint and is different than the update object O.sub.x ; and, d) generating an error message, if after the update, the applicable constraint is not satisfied by any object from the converting step.

Abstract: An element responsive to acoustic particle acceleration for sensing acoustic signals in a region of low acoustic pressure is disclosed. The element may be isolated from acoustic noise when positioned adjacent an acoustic noise generating high acoustic impedance structure by a baffle which provides isolation from radiated and evanescent acoustic signals and structure vibration.

Abstract: An array of collinear coaxial lines utilizes standard size brass tubing with brass rods inserted therein to establish each half-wavelength coaxial section. A coupler positioned between each half-wavelength section has an outer conductor supports and through passages for the inner conductor. Inner conductors of the transmission line elements are soldered to the outer conductors of the respective adjacent transmission line elements so that all elements are excited with the same phase and polarity. Air dielectric between the inner and outer conductors provides a transmission line wavelength equal to that of free space so that the length of each element in the array is a free space half-wavelength long, thereby providing an antenna gain greater than that achievable with transmission lines having solid dielectric supporting the inner conductor.