The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In fractional Fourier domain (FrFD) hopping communication, a chirp signal distinguishes others only when their center frequency and/or frequency rate difference is significant, which is not easy to realize in the band-limited underwater acoustic (UWA) channels. Hence suppressing nonoptimal order chirps in FrFD is required to facilitate the detection of UWA FrFD hopping (FrFDH) communication. In the...
Signature whistle is individually distinctive vocalization that plays a vital role in the context of social interactions and group cohesion. However, sometimes the signals overlap recorded by hydrophones when several dolphins squawk simultaneously. This impedes the further research of signature whistle in vocal interactions. An efficient blind source separation technique that can identify and separate...
Underwater noise levels are increasing due to anthropogenic activities, especially in the densely populated coastal area and open ocean. Many studies have been evaluating the effect of anthropogenic noise on marine fish. However, the more information is needed to predict any negative effects. The startle behavior responses of the Blackhead seabream (Acanthopagrus schlegelii) were researched in this...
As one of the most alarming underwater noises today, pile driving noise is the only anthropogenic sound source other than explosives that has caused the death of fish , according to the available literature. The present study explored the effects of simulated pile driving noise on the movement behavior of Litopenaeus vannamei. The experiments were conducted in a tank equipped with DSG and recording...
Single carrier frequency domain equalization (SC-FDE) is an important means of high data rate communication. Considering frequency selective fading in the underwater acoustic channel, there are some disadvantages with respect to the traditional SC-FDE. When using Frequency Domain Linear Equalization (FD-LE), the equalizer based on zero-forcing rules may magnify noise at deep fading points of frequency...
Underwater sound generated by pile driving was recorded during the Hong Kong–Zhuhai–Macau Bridge (China) construction in 2014.The important parameters on the source level, the transmission loss, the time-frequency characteristics, and the method of the noise measurement were introduced in this paper. Signal analysis showed that the waveform of pile driving resembles a series of short pulses, composed...
Like other dolphins, Sousa Chinensis produces click signals to echolocate in underwater. Research on the source level (SL) of click signal transmitted by Sousa Chinensis is beneficial to understand the survival and behavior of such animals. In the shallow sea where the Sousa Chinensis lives, the underwater environment is so complex that causes the click signals propagation to the receiving hydrophone...
Bubble curtain technology has been applied in underwater blasting engineering for decaying the sound wave. Applying it to underwater acoustic countermeasure (UAC) is bound to achieve certain results. So it is important and necessary to assess the effect of bubble curtain on underwater acoustic (UWA) communication. In this paper, we commence from the bubble resonance theory and apply the Bellhop ray...
Underwater acoustic communications are required for controlling and networking a variety of underwater or sea surface objects. Due to the unique characteristics of the underwater acoustic channel, e.g., complicated multipath propagation, selective frequency fading, extreme Doppler effect and heavy ambient noise, FH-MFSK techniques play a vital role in robust underwater acoustic communication, especially...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.