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81.
PENGZhaohui ZHANGRenhe 《声学学报:英文版》2004,23(1):71-80
A fast algorithm of sound propagation in three dimensional underwater environments is presented. On the basis of the generalized phase integral (WKBZ) theory and the beam displacement ray mode (BDRM) theory, the coupled mode parabolic equation (CMPE) theory of sound propagation in range dependent underwater environment is extended for three dimensional (3D) problems. The CMPE3D solution is expressed in terms of the normal modes in vertical direction and the coupled mode amplitude coefficients in horizontal directions. By using the WKBZ theory and the BDRM theory, the local normal mode analysis can be processed efficiently. A PE-based algorithm, which was implemented in model FOR3D by Lee D et al [“Numerical Ocean Acoustic Propagation in Three Dimensions“, World Scientific, Singapore, 1995] is also adopted to solve the coupled mode amplitude coefficients. Numerical simulations indicate that the efficiency has been greatly improved by using CMPE3D instead of the PE approximations. 相似文献
82.
LUXugang DANGJianwu 《声学学报:英文版》2005,24(3):271-279
The contributions of the static and dynamic articulatory information to speech recognition were evaluated, and the recognition approaches by combining the articulatory information with acoustic features were discussed. Articulatory movements were observed by the Electromagnetic Articulographic System for reading speech, and the speech signals were recorded simultaneously. First, we conducted several speech recognition experiments by using articulatory features alone, consisting of a number of specific articulatory channels, to evaluate the contribution of each observation point on articulators. Then, the displacement information of articulatory data were combined with acoustic features directly and adopted in speech recognition. The results show that articulatory information provides with additional information for speech recognition which is not encoded in acoustic features. Furthermore, the contribution of the dynamic information of the articulatory data was evaluated by combining them in speech recognition. It is found that the second derivative of articulatory information provided quite larger contribution to speech recognition comparing with the second derivative of acoustical information. At last, the combination methods of articulatory features and acoustic ones were investigated for speech recognition. The basic approach is that the Bayesian Network (BN) is added to each state of HMM, where the articulatory information is represented by the BN as a factor of observed signals during training the model and is marginalized as a hidden variable in recognition stage. Results based on this HMM/BN framework show a better performance than the traditional method. 相似文献
83.
ZHUOJie SUNChao 《声学学报:英文版》2004,23(3):268-277
The performance of the multistage Constant Modulus (CM) array, one of the most striking blind beamforming algorithms, for the source Directions-of-Arrival (DOA) estimation was analyzed via computer simulations and water tank experiments, and was compared to that of other DOA estimation algorithms including the ‘non-blind‘ and the ‘blind‘. Firstly, a nominal array model and an array model with gain and phase perturbations were established,respectively. Secondly, the multistage CM array algorithm was described and computer simulations were conducted. Simulation results showed that the multistage CM array could correctly estimate the DOA at the same time when the sources were blindly recovered, and the angle separating ability of the algorithm was beyond the Rayleigh resolution limit. By changing the variance of the array model errors, it was also verified that the multistage CM array was more robust to the errors than some other algorithms mentioned in this paper. Finally, water tank experiments and data processing results were provided. Situations with different array sizes and source angular separations were considered. It was shown that the results were in good agreement with computer simulations. Results of computer simulations and water tank experiments verified that the DOAs of the multiple independent sources could be blindly and robustly estimated with the multistage CM array. 相似文献
84.
86.
涡、声干扰数值模拟中的差分方法 总被引:1,自引:0,他引:1
涡、声干扰数值模拟中的差分方法居鸿宾(上海交通大学动力系,上海200030)沈孟育(清华大学工程力学系,北京100084)居鸿宾,副教授,1967年4月生于江苏泰兴,1994年5月在上海交通大学动力系获博士学位,1994年6月至1996年5月在清华大... 相似文献
87.
地声学:一门研究海底的重要学科 总被引:4,自引:0,他引:4
地声学是一门研究海底沉积物声学特性的学科,也是一门用声学方法研究海底沉积物地学特性的学科,地声学的发展和水声学、海洋学、地质学、地球物理学及地理学等多个学科有密切的关系,对于海洋工程建设,海底资源开发及港口、航道和海防等各项海洋事业的发展重要的实用意义,文章简单介绍了国内外在地声学方面的一些工作情况,说明了地声学研究所涉及的一些主要问题,并对我国今后开展研究的方向以及应当采取的措施提出一些建议和设 相似文献
88.
中国声学学会1997年青年学术会议于元月1013日在冰城哈尔滨召开,来自全国各地的七十余名代表,克服了经费紧张、旅途不便等许多困难,到会交流讨论了42篇学术论文.本次会议是由中国声学学会主办,黑龙江省自然科学基金委员会与省科协协办.中国声学学会青年工作委员会、哈尔滨工程大学与黑龙江声学学会共同承办的.中国科学院声学研究所田静研究员任会议主席,西北工业大学孙超副教授、哈尔滨工程大学杨德森副教授任会议副干席.青年工作委员会主任委员、西北工业大学马远良教授主持了会议组织委员会的工作.中国声学学会副理事长、南京大学吴文虬教授和哈尔滨工程大学杨士获教授等八位著名学者应邀到会指导,并组成优秀论文评选委员会 相似文献
89.