Abstract: An acoustical imaging system for producing high resolution medical images provides a method and apparatus for obtaining accurate velocity characterizations of samples within the human body, and for obtaining high resolution images of the samples by utilizing the velocity characterizations of the samples within the human body. The acoustical imaging system also provides a method and apparatus for efficient use of switching channels whereby for a transducer array having a plurality of transducer elements, a set of receiver channels which number less than the number of transducer elements in the array are assigned to a selected portion of the plurality of transducers in the array, wherein for any predetermined set of transducers symmetrically located about a selected transducer, the predetermined set equal in number to the number of receiver channels in the system, each receiver channel in the set of receiver channels is only assigned to one transducer in said predetermined sampling set.

Abstract: A power controller for electric locks which draw large startup current surges which controls and manages the energy of a pair of storage batteries to reliably operate such electric locks and provide steady-state power to auxiliary system components both with AC power present and in the absence thereof, so long as the stored charge in the batteries is able, to thereafter maintain a steady source of power to the system as long as possible, and to be self-starting upon the return of AC power, all without ever placing the electric locks in a partially unlocked or "hung" state. The two storage batteries are normally maintained charged through an AC power source, and both cooperate to provide the surge power. On loss of AC power, both still provide surge power so long as one can maintain the steady state power, and thereafter the other battery alone provides surge power so long as possible.

Abstract: A data transfer or replacement system for shifting blocks of data or pages between a high speed, low capacity, working memory and a low speed, high capacity backup store of a data processing system. Each block in the working memory is associated with an "A" and a "B" single bit register. Usage bits are initially inserted into the "A" registers as information from the block is utilized. After one-half of the "A" registers have been identified by associated usage bits, the "B" single bit registers are cleared, and usage bits are inserted into these "B" registers. When one-half of the "B" usage registers are "marked", the "A" registers are cleared and usage bits are then inserted in these "A" registers. Upon the necessity for introduction of additional data from the backup store into the high speed, low capacity working memory, least recently used blocks are identified as those whose associated "A" and "B" registers have not been marked.