Corresponding aspects of underwater sound channel are summarized and a proper simulation model based upon ray - model is presented ; 5 对海洋声信道的有关问题作了综述，给出了一种适合仿真系统的基于射线声学的海洋声信道模型； 5
Although most of virtual systems fix on vision , a 3d virtual sound system can make people feeling the location of sound source and environment ’ s change , and improve mutual effects of sound environments 虽然大多数虚拟系统重点在视觉方面,然而三维声音系统能使听者感知声源的位置及环境的变化,提高环境声学的声音交互作用。
So the validity of traditional objective - quantifiers in acoustics is being questioned . this is because the evaluation using db ( a ) criterion includes an a - weight filtering to compensate a sensitivity of human hearing 因此，传统a声级的实用性受到人们的怀疑，需要综合考虑人的生理、心理的影响，开展心理声学的研究，提出噪声质量的新的评价方式。
Hangzhou hing kwok - ting electronic intelligence engineering limited , established in 1995 , the company has more acoustic experts , rich experience in the construction works , long in the field of architectural acoustics and audio video systems design optimization 杭州兴鼎电子智能化工程有限公司，创建于1995年，公司拥有多名声学专家，有着丰富的工程施工经验，尤其擅长于建筑声学的设计及音视频系统的优化处理。
The element is then used to analyse an irregular shaped cavity . a semi - analytic method , in which the derivatives of stiffness matrix and mass matrix are obtained by the difference technique , for sensitivity analysis in dynamic shape optimization is presented in this dissertation 本文采用基于局部差分的半解析算法，进行特征值的灵敏度分析，并将计算结果提供给结构力学分析模块，实现了空腔声学的有限元分析和灵敏度计算。
After a detailed review on the developments of the research on thermoacoustics , as well as the latest advancements in this field , prospective applications , and a survey of theoretical fundamentals , the author ' s work focuses on the following sections : according to predecessors " explanations , as well as personal understanding on thermoacoustic effects , a qualitative explanation for the operating mechanism of thermoacoustic engines from thermodynamic viewpoint is presented 因此行波热声发动机也就成为这一领域的研究热点。本文简要回顾了热声学的历史和研究现状，并从不同角度对热声机械的基本原理进行了论述。根据前人的观点并结合自己对热声热机的理解，给出了热声热机工作机理的热力学解释。
In this paper , the main research works are as follows : 1 ) survey and analysis previous work in auv navigation and summarize : as the cumulate error , the dead - reckoning and inertial navigation systems ca n ' t be used without other modified system ; the acoustic navigation system is used only in small range , and is very expensive . 2 ) two important approaches in geophysical navigation techniques are summarized , one is terrain contour based navigation , this approach is investigated keystone today ; the other is image based navigation , due to no perfect image sensors and image seabed map , this approach has seldom been practised . 3 ) two important terrain contour based navigation algorithms has been applied to auv , one is match algorithm - based terrain contour match ( tercom ) ; the other is kalman filter - based sandia inertia terrain - aided navigation ( sitan ) 主要研究内容包括：一、总结分析了当前水下导航的常用方法和不足之处，指出基于航位推算的导航方法，存在着最大的问题就是导航误差的积累问题，如果没有修正系统，这种方法很难满足使用要求；其次指出基于声学的导航方法，造价昂贵，导航范围有限，难以满足自主水下航行器大范围导航的需求；二、总结了当前水下地形辅助导航的主要技术路线，一是基于地形高程的匹配方法，这是当前研究的重点；二是基于地形图像的匹配方法，由于缺乏良好的图像传感器，和可用的海底图像地图，目前这种方法还有待研究发展；三、将两种地形高程匹配的常用方法应用到自主水下航行器上：以相关算法为前提的地形轮廓匹配( tercom )方法和以卡尔曼滤波为基础的桑迪亚惯性地形辅助导航( sitan )方法，前者算法简单可靠，但是导航精度不高，后者虽然精度比较高，但存在着算法较为复杂、有可能发散和出现奇异值等问题。
This thesis begins with the general principle of indoor acoustics and researches on the rule of the acoustics wave spreading ; analyzing mainly the features that the acoustics wave reflex on the concave 。 secondly , this thesis analyzes and summaries the evaluation index of indoor sound quality , knowing the relation between the subjective evaluation and the objective physical quantity 。 absorbing the experience the predecessors have got on the indoor acoustics design , master the general principle and methods of indoor acoustics design 本文首先从室内声学的一般原理入手,研究声波传播规律,重点分析声波在凹面上的反射特点。其次对室内音质的评价指标进行分析和总结,了解室内音质的主观评价与客观物理量之间的关系。吸取前人在室内声学设计方面的经验,掌握室内声学设计的一般原则和方法。
If we fill in the missing blanks with such descriptions as " the megaphone was used to direct psychoacoustic frequencies that engaged the neural networks of the enemy ' s brain , causing him to think any thought and feel any emotion that the americans chose to lay on him " , then it starts to make sense 如果我们用这样的描述填补了空白，因为“扩音器被用了直接的心理声学的频率，使敌人大脑的神经网络忙碌，导致他思考任何想法和感觉任何情绪，美国人选择加在他身上” ，接着它开始制造感觉。
At the beginning of this thesis , we introduce the fundamental of the acoustics and the perceptual mechanism . next , different kinds of speech processing methods including time processing and time - frequency analysis are presented , such as short time average energy , short time cross zero analyses , short time autocorrelation function analyses and fft . at last , we focus on the sound separation , especially on single channel sound separation 在这篇文章开始的部分,我们介绍了声学的基础知识和人类声音感知的机理;接下来,我们给出了在时域处理和频域处理语音信号的一些经典的技术,比如短时平均能量分析、短时过零分析、短时自相关函数分析、快速傅立叶变换等;本文重点从理论和实验上讨论语音分离,特别是单声道语音分离的算法及其在分离音乐鼓点中应用。
