A new method of prefetching data blocks from the NVCache to the page cache in main memory and cascading prefetching n-blocks from a hard disk to the NVCache together was proposed to reduce the spin-up frequency of a h...A new method of prefetching data blocks from the NVCache to the page cache in main memory and cascading prefetching n-blocks from a hard disk to the NVCache together was proposed to reduce the spin-up frequency of a hybrid hard disk drive and thus enhance I/O performance.The proposed method consists of three steps:1) Analyzing the pattern of read requests in block units;2) Determining the number of blocks prefetched to the NVCache;3) Replacing blocks in the NVCache according to the block replacement policy.The proposed method can reduce the latency time of a hybrid hard disk and optimize the power consumption of an IPTV set-top box.Experimental results show that the proposed method provides better average response time compared to an existing adaptive multistream prefetching(AMP) method by 25.17%.It also reduces by 20.83% the average power consumption over that of the existing external caching in energy saving storage system(EXCES) method.展开更多
微通道散热器是应对电子器件散热的有效方法,但目前常规通道存在功耗大等问题。分形结构被认为是质能运输效率最高结构之一。按照Murray定律和“黄金比例phi”设计Y型和Ψ-Y型微通道的结构,得到4种微通道:Ψ-Y-M、Y-M、Ψ-Y-phi、Y-phi...微通道散热器是应对电子器件散热的有效方法,但目前常规通道存在功耗大等问题。分形结构被认为是质能运输效率最高结构之一。按照Murray定律和“黄金比例phi”设计Y型和Ψ-Y型微通道的结构,得到4种微通道:Ψ-Y-M、Y-M、Ψ-Y-phi、Y-phi。研究采用Fluent进行数值模拟,结果表明,phi型结构比Murray型结构底面温度低;Ψ型结构比Y型结构的底面温度分布更均匀。引入性能系数(coefficient of performance,COP)来评价各结构的综合性能,Ψ-Y-M的COP相较于Y-M增长了约3%,Ψ-Y-phi和Y-phi的COP都小于Y-M,前者减小约6%,后者减小约18%。展开更多
根据NB-IoT(narrow band internet of things)技术广覆盖、低功耗、低成本的优势,该文研制基于NB-IoT的低功耗温湿度采集器。该采集器以低功耗、性能良好的STM8L微控制器作为主控芯片,搭配低功耗的NB-IOT模组BC28和高精度温湿度传感器SH...根据NB-IoT(narrow band internet of things)技术广覆盖、低功耗、低成本的优势,该文研制基于NB-IoT的低功耗温湿度采集器。该采集器以低功耗、性能良好的STM8L微控制器作为主控芯片,搭配低功耗的NB-IOT模组BC28和高精度温湿度传感器SHT20以及具有看门狗功能的低功耗外部定时器TPL5010,定时将MCU从休眠状态唤醒并将数据上传至监测系统,在一定程度上解决传统的GPRS、ZigBee等通信技术功耗大、成本高、组网复杂的问题。为检验系统的可靠性,将采集器置于室内数周进行了空气温湿度实验,实验结果显示其具有较高的可靠性,监测数据有效上传率达99.72%。为测试系统的功耗,通过Fluke8845A数字万用表对采集器进行功耗实验,实验数据显示其功耗较低,可以实现一节锂离子电池供电长达3年以上的目标。展开更多
基金supported in part by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0004114)in part by the Ministry of Knowledge Economy (MKE) and Korea Institute for Advancement in Technology (KIAT) through the Workforce Development Program in Strategic Technology in part by the MKE (The Ministry of Knowledge Economy), Korea, under the CITRC (Convergence Information Technology Research Center) support program (NIPA-2012-C6150-1201-0001) supervised by the NIPA (National IT Industry Promotion Agency)
文摘A new method of prefetching data blocks from the NVCache to the page cache in main memory and cascading prefetching n-blocks from a hard disk to the NVCache together was proposed to reduce the spin-up frequency of a hybrid hard disk drive and thus enhance I/O performance.The proposed method consists of three steps:1) Analyzing the pattern of read requests in block units;2) Determining the number of blocks prefetched to the NVCache;3) Replacing blocks in the NVCache according to the block replacement policy.The proposed method can reduce the latency time of a hybrid hard disk and optimize the power consumption of an IPTV set-top box.Experimental results show that the proposed method provides better average response time compared to an existing adaptive multistream prefetching(AMP) method by 25.17%.It also reduces by 20.83% the average power consumption over that of the existing external caching in energy saving storage system(EXCES) method.
文摘微通道散热器是应对电子器件散热的有效方法,但目前常规通道存在功耗大等问题。分形结构被认为是质能运输效率最高结构之一。按照Murray定律和“黄金比例phi”设计Y型和Ψ-Y型微通道的结构,得到4种微通道:Ψ-Y-M、Y-M、Ψ-Y-phi、Y-phi。研究采用Fluent进行数值模拟,结果表明,phi型结构比Murray型结构底面温度低;Ψ型结构比Y型结构的底面温度分布更均匀。引入性能系数(coefficient of performance,COP)来评价各结构的综合性能,Ψ-Y-M的COP相较于Y-M增长了约3%,Ψ-Y-phi和Y-phi的COP都小于Y-M,前者减小约6%,后者减小约18%。
文摘根据NB-IoT(narrow band internet of things)技术广覆盖、低功耗、低成本的优势,该文研制基于NB-IoT的低功耗温湿度采集器。该采集器以低功耗、性能良好的STM8L微控制器作为主控芯片,搭配低功耗的NB-IOT模组BC28和高精度温湿度传感器SHT20以及具有看门狗功能的低功耗外部定时器TPL5010,定时将MCU从休眠状态唤醒并将数据上传至监测系统,在一定程度上解决传统的GPRS、ZigBee等通信技术功耗大、成本高、组网复杂的问题。为检验系统的可靠性,将采集器置于室内数周进行了空气温湿度实验,实验结果显示其具有较高的可靠性,监测数据有效上传率达99.72%。为测试系统的功耗,通过Fluke8845A数字万用表对采集器进行功耗实验,实验数据显示其功耗较低,可以实现一节锂离子电池供电长达3年以上的目标。
