| 1. | So far , many methods have been proposed to estimate the nominal bearing of spatially distributed source
迄今为止，已经提出了多种空间分布源波达方向估计方法。 |
| 2. | The sources are distributed on the bodies and cavity surfaces , a computer program is written to display curves of the pressure coefficient value and velocity value of the supercavity surface
通过在回转体表面和空泡表面分布源汇的方法，建立了求解回转体超空泡表面压力系数和速度的计算公式。 |
| 3. | In order to estimate the direction of arrival ( doa ) of a broadband distributed source , a class of fast algorithms , such as central frequency algorithm , median algorithm and mean algorithm , are presented
摘要针对宽带分布源到达角估计问题，提出了一类快速的估计算法，即中频法、中值法和均值法。 |
| 4. | In applications of array processing such as radar , sonar , and wireless communications , the array observed signal is best modeled as a distributed , rather than a discrete source
在雷达、声纳、无线通信等阵列处理应用环境中，由于存在丰富的多径散射，阵列观测信号更适合采用分布源模型来描述。 |
| 5. | Then this model is chose to compute the cavitating problem . the panel method employs sources to solve the problem of partially - cavitation and super - cavitation for axisymmetric body . the sources are distributed on the bodies and cavity surfaces
通过在回转体表面和空泡表面分布源汇的方法，建立了求解回转体局部空泡与超空泡流场的数值方法。 |
| 6. | 5 ) based on the noise model with a centro - hermitian covariance matrix , a differential denoising bearing estimator is developed for coherently distributed sources in unknown noise fields . its accuracy and resolution performance is analyzed theoretically and numerically
5 )针对未知噪声环境中相干分布源的方向估计问题，提出了一种差分去噪估计器，并从理论和数值结果两个方面评价了它的精度和分辨率性能。 |
| 7. | The algorithms estimate the doa of the broadband distributed source fron the secondary diagonal elements of the covariance matrices generated from every frequency domain of the received broadband signals , thus avoiding unwrapping of phases
该类算法首先将阵列接收的宽带信号变换到频率域，然后对于每个频率形成阵列接收信号协方差阵，最后由该协方差阵的次对角线元素估计宽带分布源的到达角，其主要特点是避免了相位展开。 |
| 8. | 2 ) the concept of space frequency distribution is introduced into reevaluation of incoherently distributed source model . based on the model , two low - complexity robust bearing estimators are developed . it is proved theoretically that their estimates are asymptotically unbiased and consistent
2 )从空间频率分布的角度重新评价了非相干分布源模型，提出了两种低计算复杂度的稳健的分布源波达方向估计器，并从理论上证明了它们的渐近无偏性和渐近一致性。 |
| 9. | Also , much related research requires the narrowband assumption , which is not always realistic in practical applications . it is necessary to analyze the effects of finite bandwidth to bearing estimation of spatially distributed source . additionally , more complex noise models should be dealt with in practical situations as well as that of white gaussian noise
不过，其中多数方法仅适用于小角度扩展情况，当角度扩展比较大时，需要在估计的稳健性和运算量之间进行折中；而且，许多方法要求信号传播满足窄带假设，这在实际的应用场合中可能很难得到满足，有必要分析信号带宽对分布源波达方向估计的影响；另外，也有必要考虑空间色噪声环境中的分布源波达方向估计问题。 |
| 10. | In the thesis the low drag - low noise optimization of the vehicle main form design is realized , main accomplishments are as follows . researched the knowledge of drag and flow noise , the parameters of the boundary layer are calculated by the hess - smith method and boundary layer momentum integral method . the calculation of the length of transition zone and change in boundary layer displacement thickness between laminar and turbulent states in the transition is improved , then the drag coefficient and self - noise from the transition zone are calculated as the objective functions of the optimization
主要研究内容和成果如下：对航行器绕流流场进行分析，深入研究了阻力和流噪声产生机理，建立了阻力系数和自噪声的评估数值计算模型；采用物面分布源汇法和边界层动量积分法对绕流流场的流体动力参数进行计算，改进了转捩区长度和边界层位移厚度的计算，应用于航行器头部驻点自噪声的计算；最后设计了阻力系数和自噪声数值计算程序模块。 |
