关键词： Recovery  

摘要： Event stores face the difficult challenge of continuously ingesting massive temporal data streams while satisfying demanding query and recovery requirements. Many of today’s systems deal with multiple hardware-based trade-offs. For instance, long-term storage solutions balance keeping data in cheap secondary media (SSDs, HDDs) and performance-oriented main-memory caches. As an alternative, in-memory systems focus on performance, while sacrificing monetary costs, and, to some degree, recovery guarantees. The advent of persistent memory (PMem) led to a multitude of novel research proposals aiming to alleviate those trade-offs in various fields. So far, however, there is no proposal for a PMem-powered specialized event store. Based on ChronicleDB, we will present several complementary approaches for a three-layer architecture featuring main memory, PMem, and secondary storage. We enhance some of ChronicleDB’s components with PMem for better insertion and query performance as well as better recovery guarantees. At the same time, the three-layer architecture aims to keep the overall dollar cost of a system low. The limitations and opportunities of a PMem-enhanced event store serve as important groundwork for comprehensive system design exploiting a modern storage hierarchy. © 2020, The Author(s).

关键词： Monte carlo   Grid computing   Dose   Medical accelerator   Photon beams   Geant4   G4Linac-MT   Multithreaded  

摘要： Aim: To evaluate the computation time efficiency of the multithreaded code (G4Linac-MT) in the dosimetry application, using the high performance of the HPC-Marwan grid to determine with high accuracy the initial parameters of the 6 MV photon beam of Varian CLINAC 2100C. Background: The difficulty of Monte Carlo methods is the long computation time, this is one of the disadvantages of the Monte Carlo methods. Materials and methods: Calculations are performed by the multithreaded code G4Linac-MT and Geant4.10.04.p02 using the HPC-Marwan computing grid to evaluate the computing speed for each code. The multithreaded version is tested in several CPUs to evaluate the computing speed according to the number of CPUs used. The results were compared to the measurements using different types of comparisons, TPR20.10, penumbra, mean dose error and gamma index. Results: The results obtained for this work indicate a much higher computing time saving for the G4Linac-MT version compared to the Geant4.10.04 version, the computing time decreases with the number of CPUs used, can reach about 12 times if 64CPUs are used. After optimization of the initial electron beam parameters, the results of the dose simulations obtained for this work are in very good agreement with the experimental measurements with a mean dose error of up to 0.41% on the PDDs and 1.79% on the lateral dose. Conclusions: The gain in computation time leads us to perform Monte Carlo simulations with a large number of events which gives a high accuracy of the dosimetry results obtained in this work. (C) 2020 Greater Poland Cancer Centre. Published by Elsevier B.V. All rights reserved.

关键词： multi-threading   application program interfaces   telecommunication traffic   parallel programming   software libraries   pattern classification   multiprocessing systems   packet switching   parallelisation libraries   classification process   packet classification algorithms   multicore central processing units   multithreading application program interfaces   network packets   SDN-based network applications   multicore processors   open multiprocessing  

摘要： The categorisation of network packets according to multiple parameters such as sender and receiver addresses is called packet classification. Packet classification lies at the core of Software-Defined Networking (SDN)-based network applications. Due to the increasing speed of network traffic, there is an urgent need for packet classification at higher speeds. Although it is possible to accelerate packet classification algorithms through hardware implementation, this solution imposes high costs and offers limited development capacity. On the other hand, current software methods to solve this problem are relatively slow. A practical solution to this problem is to parallelise packet classification using multi-core processors. In this study, the Thread, parallel patterns library (PPL), open multi-processing (OpenMP), and threading building blocks (TBB) libraries are examined and implemented to parallelise three packet classification algorithms, i.e. tuple space search, tuple pruning search, and hierarchical tree. According to the results, the type of algorithm and rulesets may influence the performance of parallelisation libraries. In general, the TBB-based method shows the best performance among parallelisation libraries due to using a theft mechanism and can accelerate the classification process up to 8.3 times on a system with a quad-core processor.

关键词： 多线程   跟踪采访   艾美奖   霍尔   人生大事   脱口秀   塔姆   主持人  

摘要： “艾美奖”得主塔姆伦·霍尔(Tamron Hall)是美国的超人气脱口秀主持人,去年,49岁的她经历了结婚、生子、换工作等人生大事。我们在一个典型的星期二对她进行了跟踪采访,想看看她是如何一天内极限多线程做事,兼顾婚姻、育儿与工作的。

关键词： 窄带物联网   低功耗   业务数据碎片化   优化   仿真  

摘要： 随着物联网应用的发展与普及,低功耗广域网(LPWN)越来越受到广泛的关注,其中由3GPP在2016年提出的NB-IoT就是一种低功耗广域网通信技术,目前正处于其发展的初级阶段。NB-IoT在诸多低功耗物联网技术中有着其显著的竞争优势,其中超低能耗就是一个突出特点。通过真实网络环境下的实验,发现在典型的NB-IoT应用场景中存在严重的业务数据碎片化现象,会在一定程度上降低NB-IoT终端模组的能耗利用率和使用寿命。在对NB-IoT业务数据特性分析基础上,提出了一种应用层业务数据捆绑协议,降低业务数据的碎片化率并提高终端模组能耗利用率,通过理论分析和模拟真实应用场景实验验证了协议的可行性和有效性。

关键词： 锁相环   E-FLASH   相位噪声  

摘要： 基于国内0.13 μm E-FLASH工艺,设计了一种由E-FLASH控制的锁相环芯片,为芯片提供可配置的频率源,内置LC压控振荡器、射频分频器、数字分频器、环路滤波器接口和电荷泵,实现了锁相环的全集成。芯片功耗仅为30 mA,面积仅1 mm ×1.5 mm。工艺可集成于E-FLASH工艺的片上系统,能提供良好的相位噪声和抖动特性,最高输出频率可达2.4 GHz,锁定后10 kHz频偏的相位噪声优于-116 dBc/Hz。

关键词： 超低功耗   物联网   能量效率  

摘要： Maxim公司的MAX78000是集成了基于FPUMCU和卷积神经网络加速器的超低功耗人工智能(AI)处理器.它是新品种的AI微控制器,用来建立神经网络,以实现超低功耗和在物联网(Io T)的边缘现场直播.该器件组合了最有能量效率的AI处理和现已验证了超低功耗MCU.基于硬件的卷积神经网络(CNN)加速器是电池供电的应用能实现人工智能推断而仅需化费微焦尔的能量.MAX78000是先进的系统级芯片(SoC).

关键词： CSS   HFSS   精确定位   低功耗   标识卡  

摘要： 传统腰卡或灯绳卡一般采用一次性锂电供电,需周期性更换电池,矿工更换电池及携带麻烦,电池欠压检测不准确就会导致井下作业人员无轨迹,直接影响煤矿作业人员安全管理。随着煤矿人员定位系统升级改造,井下人员定位精度要求不断提高。针对更换电池成本高、矿工携带不便、定位精度不高等问题,设计一种基于CSS精确定位技术矿灯标识卡,在不影响矿灯正常照明情况下集成矿灯内部使用。通过增加功率放大器延长通信距离,HFSS仿真优化天线设计,提高矿灯标识卡精确定位测距可靠性,实际测试验证理论设计合理性,最终满足现场实际应用。

关键词： 混合核素识别仪通讯系统   C8051F340   无线通讯   低功耗  

摘要： 本文设计了基于C8051F340的采用大面积塑料闪烁体作为探测介质,与EzUI系列彩色液晶模块EzUIV10_070K_V10构成的混合核素识别通讯系统,该通讯系统具有传输速度快、低功耗等特点。同时详细介绍其硬件组成及其软件编程思想,并通过优化代码提高了触摸屏的响应速度。

关键词： 运算放大器   恒跨导   轨到轨   低压低功耗   三倍电流镜   共源共栅  

摘要： 提出了一种恒跨导轨到轨运算放大器,输入级电路采用三倍电流镜结构,补偿输入差分对管的静态电流,降低输入级跨导变化率;中间级电路采用两个三层MOS管共源共栅结构代替传统轨到轨运算放大器中的四层MOS管套筒式共源共栅结构,实现四端输入转为双端输出,并降低电源电压;输出级电路采用交差耦合输出结构,实现轨到轨输出,同时完成双端输入转单端输出,设计一种恒跨导轨到轨运算放大器。基于TSMC 0.18μm工艺完成电路与版图设计,使用Spectre完成仿真。结果表明,在电源电压为1 V,输入电压从0 V变化到1 V时,该放大器可实现0~1 V的轨到轨输出,静态功耗仅为44μW,输入级跨导变化率为5.5%,实现了低电源电压、低功耗和恒跨导的性能指标。