This paper presents the study of vibration in each element of hard disk drive, especially the resonance of the actuator arm. The resonance occurs in hard disk drive is considered as one of the quality controlled param...This paper presents the study of vibration in each element of hard disk drive, especially the resonance of the actuator arm. The resonance occurs in hard disk drive is considered as one of the quality controlled parameter. The main purpose of the research is to investigate the relationship between the pivot bearing assembly process and the natural frequency of the actuator arm. The experiment is designed using the information from the hard disk drive manufacturer. The selected pivot bearing assembly process parameters have been controlled. The modal analysis of the assembled actuator arms has been done. The experiment results show the relationship of the specific process parameters and some of the actuator arm＇s modal frequency. The results also show that the affected vibration mode is the torsion mode only.展开更多
To meet the requirement of high-quality transmission of videos captured by unmanned aerial vehicles （UAV） with low bandwidth, a novel rate control （RC） scheme based on region-of-interest （ROI） is proposed. First...To meet the requirement of high-quality transmission of videos captured by unmanned aerial vehicles （UAV） with low bandwidth, a novel rate control （RC） scheme based on region-of-interest （ROI） is proposed. First, the ROI information is sent to the encoder with the latest high efficient video coding （HEVC） standard to generate an ROI map. Then, by using the ROI map, bit allocation methods are developed at frame level and large coding unit （LCU） level, to avoid inaccurate bit allocation produced by camera movement. At last, by using a better robustness R-2 model, the quantization parameter （QP） for each LCU is calculated. The experimental results show that the proposed RC method can get a lower bitrate error and a higher quality for reconstructed video by choosing appropriate pixel weight on the HEVC platform.展开更多
文摘This paper presents the study of vibration in each element of hard disk drive, especially the resonance of the actuator arm. The resonance occurs in hard disk drive is considered as one of the quality controlled parameter. The main purpose of the research is to investigate the relationship between the pivot bearing assembly process and the natural frequency of the actuator arm. The experiment is designed using the information from the hard disk drive manufacturer. The selected pivot bearing assembly process parameters have been controlled. The modal analysis of the assembled actuator arms has been done. The experiment results show the relationship of the specific process parameters and some of the actuator arm＇s modal frequency. The results also show that the affected vibration mode is the torsion mode only.
文摘To meet the requirement of high-quality transmission of videos captured by unmanned aerial vehicles （UAV） with low bandwidth, a novel rate control （RC） scheme based on region-of-interest （ROI） is proposed. First, the ROI information is sent to the encoder with the latest high efficient video coding （HEVC） standard to generate an ROI map. Then, by using the ROI map, bit allocation methods are developed at frame level and large coding unit （LCU） level, to avoid inaccurate bit allocation produced by camera movement. At last, by using a better robustness R-2 model, the quantization parameter （QP） for each LCU is calculated. The experimental results show that the proposed RC method can get a lower bitrate error and a higher quality for reconstructed video by choosing appropriate pixel weight on the HEVC platform.
