• The Journal of the Acoustical Society of Korea
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• v.35 no.5
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• pp.340-348
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• 2016

Ray-based model for the calculation of the ocean surface-generated ambient noise coherence function has the form of double integral with respect to a range and a bearing angle. While the theoretical consideration about its numerical implementations was partly given in the past work of authors, the numerical results on the ocean environment have not been presented yet. In this paper, we perform numerical experiments for shallow and deep water environments. It is shown that the coherence function depends on the ocean sediment sound speed, and is more sensitive to the ocean sediment sound speed in the shallow water than in the deep water. Similar trend is also observed for varying the orientation of hydrophone pair. In addition, a post-processing technique is proposed in order to plot the noise intensity for the noise receiving angle. This procedure will supplement the weakness of the ray-based model about the output data type compared to the semi-analytic model of Harrison.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.4
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• pp.318-325
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• 2003

The new biotelemetry method and system that the installation and the treatment of equipment is convenient and the instantaneously detailed position of the fish attached the pinger is able to track comparatively easily had been developed, an availabilities of it were verified in water tank by using hydrophone and pinger. First of all, the receiving system for biotelemetry was calibrated so as to measure tracking of high precision or wide detection range. In the next place, the precision at narrow and wide beam array of receiving system by using hydrophone was investigated and the actual position was compared with measured hydrophone position. The mean standard deviations of the position by narrow beam array of receiving system were 6.4em in phase beam of fore-aft pair and 6.3em in starboard-port pair, and the wide beam array were 24em and 23em respectively. The precision of distance, position, and velocity at narrow beam array of receiving system by using pinger were investigated and the actual values were compared with measured values. The distance from receiving system to pinger was measured by the pinger synchronizing method, angle of direction of pinger was detected by the super short base line (SSBL) method. The three dimensional position of pinger to the receiving system was measured by combining of two kinds of methods (SPB method), the velocity of pinger was obtained with a differential of the three dimensional positions. The mean standard deviations of the distance by pinger synchronizing method in narrow beam array of receiving system was 1. 8 em, that of the position by SPB method was 7.7cm.