Multiple receivers data processing

By means of this procedure our problem is not only reduced from three to two dimensions, but also is the statistical noise in the scattering data considerably reduced. Multiplication by —4ns2 is equivalent to the 2D Laplacian89 in physical space. It is applied for the purpose of edge enhancement. Thereafter the 2D background is eliminated by spatial frequency filtering, and an interference function G(s 2,s ) is finally received. The process is demonstrated in Fig. 8.27. 2D Fourier transform of the interference function... 

Acoustic data fusion is a technique that combines information from multiple receivers or receiving platforms about a common object or channel. Instead of each receiver making a decision, relevant information from the different receivers is sent to a common control unit where the acoustic data is combined and processed (hence the name data fusion). After fusion, a decision can be relayed or fed back to each of the receivers. If data transmission is a concern, due to time constraints, cost, or security, other techniques can be used in which each receiver makes a decision and transmits only the decision. The control unit makes a global decision based on the decisions of all of the receivers and relays this global decision back to the receivers. This is called distributed detection. The receivers can then be asked to re-evaluate their individual decisions based on the new global decision. This process could continue until all of the receivers are in agreement or could be terminated whenever an acceptable level of consensus is attained. 

Fig. 22 The processing flow chart for handling data recorded using multiple receivers...

The MFP process is illustrated in figure 8. The received signal, for all transmit/receive pairs, over a CPI forms a data cube. The matched filter, for a particular scene pixel and target velocity, also forms a data cube. For multiple operating frequencies, additional cubes would be formed. A single MFP output, a pixel and velocity, is the inner product... 

The marine environment acts as a sink for a large proportion of polyaromatic hydrocarbons (PAH) and these compounds have become a major area of interest in aquatic toxicology. Mixed function oxidases (MFO) are a class of microsomal enzymes involved in oxidative transformation, the primary biochemical process in hydrocarbon detoxification as well as mutagen-carcinogen activation (1,2). The reactions carried out by these enzymes are mediated by multiple forms of cytochrome P-450 which controls the substrate specificity of the system (3). One class of MFO, the aromatic hydrocarbon hydroxylases (AHH), has received considerable attention in relation to their role in hydrocarbon hydroxylation. AHH are found in various species of fish (4) and although limited data is available it appears that these enzymes may be present in a variety of aquatic animals (5,6,7,8). 

Pulse compression requires a separate matched filter be supported for each waveform used by the radar system. In practice, this filter is implemented via fast convolution as illustrated in Fig. 17.12. From Fourier transform theory, frequency-domain multiplication is equivalent to time-domain convolution. Hence, receiver digitized output data is input to a FFT, multiplied by the Fourier transform of the matched filter response, and then passed through an inverse FFT (I FFT) to output time-domain data. The matched filter reference functions transforms are generally computed off-line and stored in memory to support real-time processing. Fast convolution significantly reduces the number of operations required compared to time-domain direct convolution of returns and the appropriate matched filter function. 

In message passing, SEND and RECEIVE operations are used to synchronize, and to pass data via a specified communication channel. At one end of the message-passing spectrum, the SEND can refer to the specific process to which the information is sent, and the RECEIVE can refer to the specific process from which the information is received this option is referred to as direct naming. At the other end of the spectrum, the SEND and RECEIVE can refer to global mailboxes. Since the mailbox is not directly tied to a particular process, this method is more general, and provides better support for client / server interaction, where there are multiple clients or servers. 

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