Research of whispered speech vocal tract system conversion based on universal background model and effective Gaussian components

Directing to the weakness of the present fixed values mapping methods （method_F）, a vocal tract system conversion method based on the universal background model （UBM） is proposed for improving the performance of the speech conversion system from Chinese whis- pered speech to normal speech. For the numerous components of UBM, the errors produced by the acoustical probability density statistical model can＇t be ignored. Thus an effective Gaus- sian mixture components chosen method based on the posterior probability summation of the minimum spectral distortion is developed to optimizing the system performance. The proposed method （method_U） is analyzed and compared using the performance index （PI） based on Itakura-Saito spectral distortion measure. It is shown experimentally that the performance of method_U is more stability for different speakers and different phonemes than that of method_F. The average PI of method_U is better than method_F. It is shown that by selecting effective Gaussian mixture components, the PI of method_U can be further improved 5.11%. Subjective auditory tests also show that the proposed method can improve the definition and intelligibility of conversion speech.

关于变频多联机APF能效试验中针对低温制冷实测时准确性的检讨和建议

目前我国多联机变频空调机组均采用全年性能系数(APF)替代IPLV作为评价指标。基于现有多联变频空调器的调节范围广的特点,指出了现有APF中对于选择性试验即低温制冷工况实测时,会出现不符合实际的情况,利用实测数据和理论分析产生的原因,水平展开,并给出了针对实测的改进建议。

压缩机表面产生凝露的原因及其解决措施

变频多联机中距离室内机近的压缩机表面在运行中出现凝露现象,并伴随压缩机内油翻泡,油面下降。从理论方面分析该现象:在名义制冷、最大制冷工况下,制冷剂循环量没有控制好,导致过多的制冷剂进入压缩机后继续蒸发,温度降低到露点温度以下,从而出现压缩机表面凝露。为此,提出相应的控制措施,较好地解决了该问题,对保证多联机系统的稳定安全可靠运行具有一定的指导意义。

变频多联机产生过电流的原因与解决措施

针对变频多联机在模块切换、制热除霜退出和回油退出时所出现的过电流现象,分析试验数据,找到产生过电流的原因,并提出解决措施,为多联机的安全可靠运行提供保障。