The paper applies spectral analysis to the underwater acoustic noise radiated by ships. A frequency band is specified to characterize the sound produced by different platforms. Hence the paper proposes a new technique for feature extraction by applying autocorrelation technique and discrete cosine transform. The features extracted are employed by a recognition engine that uses Gaussian mixture ...

Due to concern about the current state of the world’s oceans, several large-scale scientific projects have begun to investigate the condition of our oceans. These projects are making use of underwater video sequences to monitor marine species. The move to using underwater video monitoring introduces labour intensive manual processing techniques. This leads to the need for an automated system ca...

S ensors and other data sources, combined with sophisticated signal processing techniques, promise to help scientists better observe and analyze various types of environmental data. Biologist Nathan Merchant, for example , has created a method for tracking ships and monitoring underwater noise levels in protected marine mammal habitats. Merchant, senior scientist for underwater noise at the U.K...

Underwater acoustic channel (UAC) is one of the most challenging communication channels in the world, owing to its complex multi-path and absorption as well as variable ambient noise. Although adaptive equalization could effectively eliminate the inter-symbol interference (ISI) with the help of training sequences, the convergence rate of equalization in sparse UAC decreased remarkably. Besides,...

the effect of underground cavities in site seismic response was studied over the subway tunnels that are under construction in the city of karaj, using ambient noise measurements as well as numerical modeling. the idea for this research comes from the observation of differences in experimental site transfer function, calculated on more than 100 locations of the city, for the areas near the unde...

Introduction The seismic frequency band can be defined from 0.3 mhz to tens or hundreds of hz, in which the lower limit is defined by the period of the gravest observed free mode of the Earth (0s2). Digital seismic recordings in this frequency band always contain noise, which essentially can be attributed to ambient Earth noise and instrumental noise, or self-noise, of the recording system. Ins...