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Model of Shipping Noise in the Deep Water: Directional Density and Spatial Coherence Functions
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作者 肖鹏 杨坤德 雷波 《China Ocean Engineering》 SCIE EI CSCD 2016年第4期591-601,共11页
The shipping noise properties in the deep ocean are studied. Shipping noise exhibits the strong dual-horned directionality features in the flat-seabed ocean, and its directional density can be modeled by a Von Mises d... The shipping noise properties in the deep ocean are studied. Shipping noise exhibits the strong dual-horned directionality features in the flat-seabed ocean, and its directional density can be modeled by a Von Mises distribution. With the explicit expression for the directional density function, the spatial coherence functions of shipping noise are also derived, and the relative features are studied. The research result shows that the properties of shipping noise are different from the ambient noise of other sources, and it can be used for the sonar array design. The model is well matched with the experimental result, and it can be extended to the situations when the ambient noise exhibits the dual-horned structure. 展开更多
关键词 shipping noise dual-horued structure Von Mises distribution directional density spatial coherence
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Extracting Acoustic Source Information of Shipping Noise for Dynamic Ambient Noise Modelling 被引量:1
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作者 Giuliana Pennucci Yong-Min Jiang 《Journal of Shipping and Ocean Engineering》 2018年第1期10-20,共11页
Shipping traffic is one of the largest contributors to anthropogenic noise in the ocean. Noise generated by merchant ships elevates natural occurring ambient noise level by 20-30 dB in many areas of the world's ocean... Shipping traffic is one of the largest contributors to anthropogenic noise in the ocean. Noise generated by merchant ships elevates natural occurring ambient noise level by 20-30 dB in many areas of the world's ocean. In order to model the contributions of the noise generated by merchant ships to underwater ambient noise level correctly, a database that consists of the source levels as a function of frequency for different types of ships is essential. This paper describes the conceptual design, with an emphasis on the characteristics of shipping noise as sound sources, of a marine noise database. It was developed for providing necessary parameters for underwater ambient noise modelling. The parameters relevant to shipping noise modelling are organized in two catalogues: (l) source-receiver geometry related parameters, namely the coordinates of the ships at a given time period, as well as the sizes/types of the ships from which the noise source depths may be derived, and (2) acoustically relevant parameters, i.e., the acoustic SLs (source levels) at given frequencies. An example is presented here to demonstrate the efficacy of this database. The study area is a 117 × 55 km2 region off the coast of La Spezia, Italy, in the Mediterranean Sea. 展开更多
关键词 Underwater ambient noise modelling shipping SLS underwater ambient noise level ship radiated noise.
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Acoustic multipath structure in direct zone of deep water and bearing estimation of tow ship noise of towed line array 被引量:1
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作者 Zhi-Bin Han Zhao-Hui Peng +3 位作者 Jun Song Lei Meng Xiu-Ting Yang Bing Su 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第5期429-437,共9页
In the towed line array sonar system,the tow ship noise is the main factor that affects the sonar performance.Conventional noise cancelling methods assume that the noise is towards the endfire direction of the array.A... In the towed line array sonar system,the tow ship noise is the main factor that affects the sonar performance.Conventional noise cancelling methods assume that the noise is towards the endfire direction of the array.An acoustic experiment employing a towed line array is conducted in the western Pacific Ocean,and a strange bearing-splitting phenomenon of the tow ship noise is observed in the array.The tow ship noise is split into multiple noise signals whose bearings are distributed between 10°and 90°deviating from the endfire direction.The multiple interferences increase the difficulty in recognizing the target for the sonar operator and noise cancellation.Therefore,making the mechanism clear and putting forward the tow ship noise splitting bearing estimation method are imperative.In this paper,the acoustic multi-path structure of the tow ship in deep water is analyzed.Then it is pointed out that the bearing-splitting phenomenon is caused by the main lobe of direct rays and bottom-reflected rays,as well as several side lobes of direct rays.Meanwhile,the indistinguishability between the elevation angle and the bearing angle due to the axial symmetry of a strict horizontal line array causes the bearing to deviate from the endfire direction.Based on the theory above,a method of estimating bearing of the tow ship noise in deep water is proposed.The theoretical analysis results accord with the experimental results,which helps to identify the target and provide correct initial bearing guidance for noise cancelation methods. 展开更多
关键词 deep water direct zone towed line array the tow ship noise
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The load criteria for ship mechanical noise prediction in low frequencies and experimental validation
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作者 Xi-An Liu De-Qing Yang Qing Li 《Journal of Ocean Engineering and Science》 SCIE 2023年第3期278-293,共16页
The loading method of the external excitations generated by the equipment directly affects the predicted result of the mechanical noise which should be the same under different excitation forms for the given equipment... The loading method of the external excitations generated by the equipment directly affects the predicted result of the mechanical noise which should be the same under different excitation forms for the given equipment.In this paper,general load criteria are proposed to define forces/moments as the standard form and convert other forms of loads in the low-frequency domain.As the most typical form to charac-terize equipment excitation,acceleration load loading methods for different conditions are investigated.The equivalent formula between ideal accelerations and generalized forces establishes the first load cri-terion.The second load criterion is proposed to address the issue of an average acceleration loading,in which the phase and amplitude distribution are both absent,and cannot apply to the load identification.The upper and lower limits of the mechanical noise can be determined by the vibroacoustic transfer func-tion of the three load models,and the energy-averaged value is used to represent the mechanical noise.Furthermore,the third criterion is used to handle the case where the acceleration load is given by the results of a bench test.According to the equipment source descriptor invariance,the conversion method is achieved between the bench test and the real ship based on the transfer function of a load model,and the mechanical noise is predicted by an equivalent energy method.Finally,a three-parameter method to quantitatively evaluate the well-fitting of experimental and numerical results,and the load criteria are well validated by underwater acoustic experiments of an experimental model. 展开更多
关键词 Ships’mechanical noise Load criteria Vibroacoustic transfer functions Underwater acoustic experiments Accelerations load Three-parameter method
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Receiving response of towed line array to the noise of the tow ship in shallow water 被引量:10
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作者 MA Yuanliang LIU Mengan ZHANG Zhongbing TONG Li(1 Institute of Acoustic Engineering, Northwestern Polytechnical University Xi’an 710072) (2 Hangzhou Institute of Applied Acoustics Fuyang 311400) 《Chinese Journal of Acoustics》 2003年第1期1-10,共10页
The receiving response of towed line array to the noise radiated from the tow ship is investigated through normal mode modeling and computer simulation. The phenomenon that the maximum output of the towed line array i... The receiving response of towed line array to the noise radiated from the tow ship is investigated through normal mode modeling and computer simulation. The phenomenon that the maximum output of the towed line array is away from the endfire direction towards the tow ship is explained. The result is important for the understanding of the phenomenon and also for the application research concerning the suppression of the noise from the tow ship as well as adequate application of towed array techniques in shallow water. 展开更多
关键词 LINE AS of Receiving response of towed line array to the noise of the tow ship in shallow water in IS
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Frequency correlation and group time delay of ambient noise and ship radiated-noise in the sea 被引量:2
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作者 ZHANG Renhe WANG Futang HOU Wenliang and JI shunxin(State Key Laboratory of Acoustics, Chinese Academy of Sciences, Beijing 100080) 《Chinese Journal of Acoustics》 1995年第3期276-279,共4页
The characteristics of frequency correlation and group time delay of ambient noise and ship radiated-noise in the sea are studied. The theoretical and experimental results show that the frequency correlation of ship r... The characteristics of frequency correlation and group time delay of ambient noise and ship radiated-noise in the sea are studied. The theoretical and experimental results show that the frequency correlation of ship radiated-noise is much greater than that of ambient noise,and the frequency correlation of ship radiated-noise at long distance has obvious group time delay 展开更多
关键词 TIME Frequency correlation and group time delay of ambient noise and ship radiated-noise in the sea
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A trial of using the cluster analysis to classify the ship noises and EEG (electroencephalogram)
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作者 CHEN Geng and WEI Xuehuan(Institute of Acoustics Academia Sinica) WANG Yuhong and JIN Zhang lei(Institute of Aeroforce Medicine) 《Chinese Journal of Acoustics》 1991年第1期37-46,共10页
Cluster analysis is a method often used in pattern recognition. With the aid of the signal processing and the learning of the computer, disfferent samples can be classifeid and recognized in a dimension reduction spac... Cluster analysis is a method often used in pattern recognition. With the aid of the signal processing and the learning of the computer, disfferent samples can be classifeid and recognized in a dimension reduction space of the characteristics because of the differences of their character -istics. To realize dimension reduction transformation, a nonlinear mapping method was discussed in this paper. To prove that the cluster analysis is suitable for quite different fields of samples, in this paper some ship noises and some EEG as the samples belong to two different fields are classified and shown. And it is worthy to point out that an adaptive step size expression of adaptive iteration deduced here will also be effective if it is applied to speed adaptive algorithm convergence of general signal processing. 展开更多
关键词 A trial of using the cluster analysis to classify the ship noises and EEG ELECTROENCEPHALOGRAM
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Fractal Brownian motion model of ship radiated noise
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作者 CHEN Xiangdong GAO Xiang LU Jiren(Dept. of Radio Eng., Southeast University Nanjing 210018) 《Chinese Journal of Acoustics》 1999年第1期10-18,共9页
On the basis of the fractal geometry, a nactional Brownian Motion (FBM) model for the noise radiated by ship was established, under which its fractal dimension has been obtained and the Fractal Characteristic Vector (... On the basis of the fractal geometry, a nactional Brownian Motion (FBM) model for the noise radiated by ship was established, under which its fractal dimension has been obtained and the Fractal Characteristic Vector (FCV) was constructed in the fractional Brownian random field (FBRF). By using of them, a new technique of the characteristic analysis for target recognition in the underwater acoustics was presented. A comparative experiment for classification shows us that the FCV can be used as essential quantity by which some defects existing in the methods to do the characteristic extraction elsewhere can be remedied. 展开更多
关键词 Fractal Brownian motion model of ship radiated noise ITI
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