针对EB(extreme binning)算法重复数据删除率低,磁盘I/O开销大的缺陷,提出基于多特征匹配和Bloom filter的重复数据删除算法DBMB(deduplication based on multi-feature matching and Bloom filter).将小文件聚合为局部性文件单元,作为...针对EB(extreme binning)算法重复数据删除率低,磁盘I/O开销大的缺陷,提出基于多特征匹配和Bloom filter的重复数据删除算法DBMB(deduplication based on multi-feature matching and Bloom filter).将小文件聚合为局部性文件单元,作为一个整体进行去重处理,采用最大、最小以及中间数据块ID的多重相似性特征进行匹配,并基于Bloom filter优化磁盘数据块的查找和匹配过程.结果表明,DBMB算法能有效提升重复数据删除率,降低算法执行时间,同时减少处理小文件的内存开销,性能提升显著.展开更多
Sensitivity loop shaping using add-on peak filters is a simple and effective method to reject narrow-band disturbances in hard disk drive （HDD） servo systems. The parallel peak filter is introduced to provide high-g...Sensitivity loop shaping using add-on peak filters is a simple and effective method to reject narrow-band disturbances in hard disk drive （HDD） servo systems. The parallel peak filter is introduced to provide high-gain magnitude in the concerned frequency range of open-loop transfer function. Different from almost all the known peak filters that possess second-order structures, we explore in this paper bow high-order peak filters can be designed to improve the loop shaping performance. The main idea is to replace some of the constant coefficients of common second-order peak filter by frequency-related transfer functions, and then differential evolution （DE） algorithm is adopted to perform optimal design. We creatively introduce chromosome coding and fitness function design, which are original and the key steps that lead to the success of DE applications in control system design. In other words, DE is modified to achieve a novel design for hard disk drive control. Owing to the remarkable searching ability of DE, the expected shape of sensitivity function can be achieved by incorporating the resultant high-order peak filter in parallel with baseline feedback controller. As a result, a seventh-order peak filter is designed to compensate for contact-induced vibration in a high-density HDD servo system, where the benefits of high-order filter are clearly demonstrated.展开更多
In this paper we present a novel method to fabricate reliable micro-electro-mechanical system（MEMS） disk resonators with high yield and good performance.The key breakthrough in the fabrication process is a novel app...In this paper we present a novel method to fabricate reliable micro-electro-mechanical system（MEMS） disk resonators with high yield and good performance.The key breakthrough in the fabrication process is a novel approach to effectively restraining electro-chemical corrosion of polycrystalline silicon（polysilicon） electrically coupled with noble metals of MEMS devices by hydrofluoric acid（HF）-based solutions.In addition,a measurement architecture based on a differential readout topology is demonstrated.The differential circuit proposed here can effectively suppress noise and feed-through current by common-mode rejection of the differential amplifier.This differential amplifier circuit configuration is also used to build up a notch filter.The preliminary result about the temperature dependence of the resonance frequency is discussed,and the device failure is analysed.展开更多
文摘针对EB(extreme binning)算法重复数据删除率低,磁盘I/O开销大的缺陷,提出基于多特征匹配和Bloom filter的重复数据删除算法DBMB(deduplication based on multi-feature matching and Bloom filter).将小文件聚合为局部性文件单元,作为一个整体进行去重处理,采用最大、最小以及中间数据块ID的多重相似性特征进行匹配,并基于Bloom filter优化磁盘数据块的查找和匹配过程.结果表明,DBMB算法能有效提升重复数据删除率,降低算法执行时间,同时减少处理小文件的内存开销,性能提升显著.
基金supported by National Natural Science Foundation of China(Nos.61640310 and 61433011)
文摘Sensitivity loop shaping using add-on peak filters is a simple and effective method to reject narrow-band disturbances in hard disk drive （HDD） servo systems. The parallel peak filter is introduced to provide high-gain magnitude in the concerned frequency range of open-loop transfer function. Different from almost all the known peak filters that possess second-order structures, we explore in this paper bow high-order peak filters can be designed to improve the loop shaping performance. The main idea is to replace some of the constant coefficients of common second-order peak filter by frequency-related transfer functions, and then differential evolution （DE） algorithm is adopted to perform optimal design. We creatively introduce chromosome coding and fitness function design, which are original and the key steps that lead to the success of DE applications in control system design. In other words, DE is modified to achieve a novel design for hard disk drive control. Owing to the remarkable searching ability of DE, the expected shape of sensitivity function can be achieved by incorporating the resultant high-order peak filter in parallel with baseline feedback controller. As a result, a seventh-order peak filter is designed to compensate for contact-induced vibration in a high-density HDD servo system, where the benefits of high-order filter are clearly demonstrated.
基金Project supported by the National Basic Research Program of China (Grant Nos. 2009CB320305 and 2011CB933102)
文摘In this paper we present a novel method to fabricate reliable micro-electro-mechanical system（MEMS） disk resonators with high yield and good performance.The key breakthrough in the fabrication process is a novel approach to effectively restraining electro-chemical corrosion of polycrystalline silicon（polysilicon） electrically coupled with noble metals of MEMS devices by hydrofluoric acid（HF）-based solutions.In addition,a measurement architecture based on a differential readout topology is demonstrated.The differential circuit proposed here can effectively suppress noise and feed-through current by common-mode rejection of the differential amplifier.This differential amplifier circuit configuration is also used to build up a notch filter.The preliminary result about the temperature dependence of the resonance frequency is discussed,and the device failure is analysed.
