1. At present, there are several methods for grinding wheel wear monitoring and inspection such as acoustic emission testing, hydrodynamic measurement in wet grinding, optical projection reading method, etc.
    目前，有多少种办法砂轮磨损监测和检查，如声发射测试，流体力学测量中的湿磨，投影光学阅读办法等[3-7] 。

2. The method of projection is used to feature extraction and recognition of the underwater acoustic images obtained by sonar imaging.
    用投影变换的方法进行了成像声纳采集的水声图像特征提取与识别。

3. Acoustic source localization based on adaptive subgradient projection in digital hearing aids
    基于次梯度投影的数字助听器自适应声源定位方法

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4. In the field of acoustic echo cancellation, multi-channel affine projection algorithm (MCAP) has fast convergence rate but big computational complexity.
    声回波对消领域中，多通道仿射投影算法具有良好的收敛性能，但计算复杂度较高。