An experimental program was run by the Centre for Marine Science and Technology of Curtin University between March 1996 and October 1999 to study the environmental implications of offshore seismic survey noise. This work was initiated and sponsored by the Australian Petroleum Production and Exploration Association. The program:characterised air gun signal measurements; modelled air gun array sources and horizontal air gun signal propagation;developed an 'exposure model' to predict the scale of potential biological effects for a given seismic survey over its duration;made observations of humpback whales traversing a 3D seismic survey;carried out experiments of approaching humpback whales with a single operating air gun;carried out trials with an air gun approaching a cage containing sea turtles, fishes or squid; andmodelled the response of fish hearing systems to airgun signals.The generalised response of migrating humpback whales to a 3D seismic vessel was to take some avoidance manoeuvre at >4 km then to allow the seismic vessel to pass no closer than 3 km. Humpback pods containing cows which were involved in resting behaviour in key habitat types, as opposed to migrating animals, were more sensitive and showed an avoidance response estimated at 7−12 km from a large seismic source. Male humpbacks were attracted to a single operating air gun due to what was believed the similarity of an air gun signal and a whale breaching event (leaping clear of the water and slamming back in). Based on the response of captive animals to an approaching single air gun and scaling these results, indicated sea turtles displayed a general 'alarm' response at an estimated 2 km range from an operating seismic vessel and behaviour indicative of avoidance estimated at 1 km. Similar trials with captive fishes showed a generic fish 'alarm' response of swimming faster, swimming to the bottom, tightening school structure, or all three, at an estimated 2−5 km from a seismic source. Modelling the fish ear predicted that at ranges
During October to November 1996 WMC Petroleum conducted the Robert 3D seismic survey to the northeast of North West Cape, off Exmouth Western Australia. The survey used one of two 2678 cui (44 L) air-gun arrays of source level 258 dB re 1µPa2−m p−p below the array (77 bar-m), operating every eight s for 33.4 days of continual operation. Tracklines ran east-west across the path of southerly migrating humpback whales. Before the seismic survey began aerial surveys determined that humpbacks moving through the seismic area were distributed uniformly seaward of the 20 m depth contour. Based on observations made from the operating Geco Resolution there did not appear to be any gross changes in the migratory path of humpback whales through the seismic area. Whales approaching the operating Geco Resolution began avoidance manoeuvres at 5−8 km and mostly kept a standoff range of 3−4 km. Some whales approached the vessel closer. Experiments were carried out in Exmouth Gulf where the movements and behaviour of humpback pods were monitored before, during and after an approach with a 20 cui air-gun (0.33 L) of horizontal source level 227 dB re 1µPa2−m p−p. The levels at which avoidance manoeuvres began during these trials was approximately 159 dB re 1µPa2 p−p, which is roughly equivalent to the received level of the 2678 cui array at 5 km, at 162 dB re 1µPa2 p−p. General avoidance of the 20 cui air-gun was observed at 1 km, or a level of 168 dB re 1µPa2 p−p, which was roughly equivalent to the level of the 2678 cui array at 3 km at 170 dB re 1µPa2 p−p, which was the general minimum humpback standoff range observed from this array. Whales were observed to move closer to the operating 20 cui and 2678 cui air-gun/array. It is speculated that these whales were mostly males intent on investigating or passing quickly by the appropriate air-gun/array.
The predominant melodic source, frequently the singing voice, is an important component of musical signals. In this paper we describe a method for extracting the predominant source and corresponding melody from "real-world" polyphonic music. The proposed method is inspired by ideas from Computational Auditory Scene Analysis. We formulate predominant melodic source tracking and formation as a graph partitioning problem and solve it using the normalized cut which is a global criterion for segmenting graphs that has been used in Computer Vision. Sinusoidal modeling is used as the underlying representation. A novel harmonicity cue which we term Harmonically Wrapped Peak Similarity is introduced. Experimental results supporting the use of this cue are presented. In addition we show results for automatic melody extraction using the proposed approach.
Portable digital music players are becoming pervasive and the size of personal digital music collections has been steadily increasing (5-10 thousand tracks are common today). The emerging area of Music Information Retrieval (MIR) deals with all aspects of managing, analyzing and organizing music in digital formats. The majority of work in MIR follows a search/retrieval paradigm. More recently, the importance of browsing as an interaction paradigm has been realized and several novel interfaces have been proposed. In this paper, we describe a tangible interface for content-aware browsing of music collections. The Radio Drum is a gestural interface based on capacitance sensors that can detect the x,y,z positions of two drum sticks in a 3D volume. We describe two possible mappings that can be be used for browsing music collections without relying on metadata. The first is an explicit mapping of tempo and beat strength, and the second is a music similarity space using audio feature extraction and a Self Organizing Map (SOM).
Clustering based on the normalized cut criterion, and more generally, spectral clustering methods, are techniques originally proposed to model perceptual grouping tasks, such as image segmentation in computer vision. In this work, it is shown how such techniques can be applied to the problem of dominant melodic source separation in polyphonic music audio signals. One of the main advantages of this approach is the ability to incorporate mutiple perceptually-inspired grouping criteria into a single framework without requiring multiple processing stages, as many existing computational auditory science analysis approaches do. Experimental results for several tasks, including dominant melody pitch detection, are presented. The system is based on a sinusoidal modeling analysis front-end. A novel similarity cue based on harmonicity (harmonically-wrapped peak similariy) is also introduced. The proposed system is data-driven (i.e., requires no prior knowledge about the extracted source), causal, robust, practical, and efficient (close to real-time on a fast computer). Although a specific implementation is presented, one of the main advantages of the proposed approach is its ability to utilize different analysis front-ends and grouping criteria in a straightforward manner.
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