Abstract:
A method of obtaining trace data with respect to a running software program includes accessing a method in a call stack, the call stack including a sequentially ordered list of methods called during the running of the software program. If the accessed method in the call stack falls between a minimum trace offset and a maximum trace offset where the minimum trace offset and the maximum trace offset define a trace window, obtaining trace data for the method and outputting it to an output stream which is then collected into a trace data storage. If the trace data in the trace data storage meets predetermined adaptation rules then changing the position in the call stack of at least one of the minimum trace offset and the maximum trace offset.
Abstract:
Measuring apparatus for providing information on the relative location of a target site which is radiating a target signal that includes a predetermined pulse signal, comprises receiver means for providing a pair of temporally spaced output pulses in response to a single received said predetermined pulse signal and cross-correlation means coupled to said receiver means for cross-correlating said pair of output pulses or signals derived therefrom.
Abstract:
For digital underwater transmission an information sequence (17) of digital bits is partitioned into a succession of symbols each comprising n bits where n is equal to or greater than one (2n potential symbols), each symbol (19) is replaced (20) a corresponding base code sequence of length m bits and the result (21) is passed to an acoustic transducer after bi-phase modulation (22) on a carrier. The code has good correlation properties, e.g. a pseudo-random maixmal length sequence, a Gold code or a Kasami code, and the value of m/n is at least (32). Preferably the base sequence is cyclically extended at one or both ends prior to modulation, and Solomon Reed redundancy coding (18) is initially applied to the information sequence. The output (23) of modulator (22) may be prefaced (26) by a pair of chirp waveforms (24). Provision is made for Doppler and multi-path correction.
Abstract:
In a digital acoustic transmission device in which a digital sequence (31) is electrically modulated (22) on a carrier cos ωt, the modulated carrier (23) is prefaced with at least two pulse signals (24) of known timing relative to each other and to the modulated digital sequence to provide an output signal (13) for acoustic transmission. The pulse signals indicate to receiver the start of a transmission, and contain Doppler information for resampling the modulated signal prior to demodulation. Where the information sequence is in encoded blocks of equal length, the relationship between successive blocks can be used to update the Doppler information for use with the following block. Channel information can also be derived from the pulse signals and/or blocks for raking the next part of the incoming signal. Preferably the pulse signals have good correlation characteristics. In the embodiments the pulse signals are an immediately successive identical pair of linearly rising chirps.
Abstract:
A method of underwater communication between a link initiator and a link receptor, by transmitting a link acquisition waveform from the initiator to the receptor, and establishing communications channel parameters from such a received waveform. Data is then transmitted according to these parameters, which may include range, direction, frequency band and Doppler, with greater efficiency and robustness.
Abstract:
A method of underwater communication between a link initiator and a link receptor, by transmitting a link acquisition waveform from the initiator to the receptor, and establishing communications channel parameters from such a received waveform. Data is then transmitted according to these parameters, which may include range, direction, frequency band and Doppler, with greater efficiency and robustness.
Abstract:
A method for the flotation processing of mineral ores is disclosed. At least one collector is introduced into the flotation process by atomization. In a preferred aspect of the invention, the collector is provided as a mixture of the thiol and corresponding oxidized thiol (e.g., a dithiol).