关键词： 儿童追踪器   ZigBee   定位   低功耗  

摘要： ZigBee技术是一种用于无线设备之间的,借助无线通信协议来实现短距离无线数据的接收和发送的通信方式。随着我国人民的生活水平逐步提高,社会越来越关注和重视有关儿童安全的问题。本文设计了一种基于ZigBee技术的儿童追踪器,它采用GPS定位技术和ZigBee无线通信技术,以达到在PC机上对儿童定位实时追踪的功能。在本系统的数据采集节点中,ZigBee终端拓展的定位模块用于对儿童所在位置进行定位数据的采集,并借助传输节点发送定位信息到PC端的上位机进行实时显示。与传统的系统相比,该系统具有低功耗、电路简单等特点。

关键词： 液位监测   低功耗   智慧城市   物联网   STM32   GPRS  

摘要： 针对智慧城市发展过程中对窨井液位低功耗监测的需求,设计了一种基于STM32的低功耗窨井液位采集与传输系统,该系统能够采集液位值、电池电压和故障码数据,利用GPRS模块将数据传输到接收端或云端。系统中的MOS电路能够控制耗能模块的启停,降低系统功耗。为提高系统采集的灵活性,采用浮球开关作为液位上涨触发信号,进而更改系统工作模式。通过实验测试,得到系统工作在不同阶段的电流消耗情况,估算出系统一年的总功耗为12.01 A·h,表明系统能够在低功耗条件下稳定运行。

关键词： 雷达信号处理   GNU Radio软件平台   多线程   模块化   传输内存地址  

摘要： 针对现有雷达仿真系统的单线程运行模式在处理较大数据量或多任务执行时会造成CPU负担加重、导致系统运行速度缓慢与数据丢失,进而影响仿真测试的实效性等问题,提出了基于GNU Radio软件平台利用其多线程技术与模块化思想,同时设计并使用传输内存地址的方法来搭建雷达信号系统,提升计算机的资源利用率。多线程模式下的系统运行不仅能够对大量数据进行处理,而且能提升其处理数据的速度,同时兼具美观性与操作性。最后的测试数据表明了雷达信号处理系统的有效性,达到了预期的设计目标,满足了实际应用需求。

关键词： FPGA   CAM   Hash join   Aggregation   Main memory   Relational database  

摘要： The join and group-by aggregation are two memory intensive operators that are affecting the performance of relational databases. Hashing is a common approach used to implement both operators. Recent paradigm shifts in multi-core processor architectures have reinvigorated research into how the join and group-by aggregation operators can leverage these advances. However, the poor spatial locality of the hashing approach has hindered performance on multi-core processor architectures which rely on using large cache hierarchies for latency mitigation. Multithreaded architectures can better cope with poor spatial locality by masking memory latency with many outstanding requests. Nevertheless, the number of parallel threads, even in the most advanced multithreaded processors, such as UltraSPARC, is not enough to fully cover the main memory access latency. In this paper, we explore the hardware re-configurability of FPGAs to enable deeper execution pipelines that maintain hundreds (instead of tens) of outstanding memory requests across four FPGAs-drastically increasing concurrency and throughput. We present two end-to-end in-memory accelerators for the join and group-by aggregation operators using FPGAs. Both accelerators use massive multithreading to mask long memory delays of traversing linked-list data structures, while concurrently managing hundreds of thread states across four FPGAs locally. We explore how content addressable memories can be intermixed within our multithreaded designs to act as a synchronizing cache, which enforces locks and merges jobs together before they are written to memory. Throughput results for our hash-join operator accelerator show a speedup between 2x and 3.4x over the best multi-core approaches with comparable memory bandwidths on uniform and skewed datasets. The accelerator for the hash-based group-by aggregation operator demonstrates that leveraging CAMs achieves average speedup of 3.3x with a best case of 9.4x in terms of throughput over

关键词： image coregistration   SAR registration   high performance computing (HPC)   parallel processing   multithreading   synthetic aperture radar (SAR)   SAR interferometry (InSAR)  

摘要： Within the framework of multi-temporal Synthetic Aperture Radar (SAR) interferometric processing, image coregistration is a fundamental operation that might be extremely time-consuming. This paper explores the possibility of addressing fast and accurate SAR image geometric coregistration, with sub-pixel accuracy and in the presence of a complex 3-D object scene, by exploiting the parallelism offered by shared-memory architectures. An efficient and scalable processor is proposed by designing a parallel algorithm incorporating thread-level parallelism for solving the inherent computationally intensive problem. The adopted functional scheme is first mathematically framed and then investigated in detail in terms of its computational structures. Subsequently, a parallel version of the algorithm is designed, according to a fork-join model, by suitably taking into account the granularity of the decomposition, load-balancing, and different scheduling strategies. The developed parallel algorithm implements parallelism at the thread-level by using OpenMP (Open Multi-Processing) and it is specifically targeted at shared-memory multiprocessors. The parallel performance of the implemented multithreading-based SAR image coregistration prototype processor is experimentally investigated and quantitatively assessed by processing high-resolution X-band COSMO-SkyMed SAR data and using two different multicore architectures. The effectiveness of the developed multithreaded prototype solution in fully benefitting from the computing power offered by multicore processors has successfully been demonstrated via a suitable experimental performance analysis conducted in terms of parallel speedup and efficiency. The demonstrated scalable performance and portability of the developed parallel processor confirm its potential for operational use in the interferometric SAR data processing at large scales.

关键词： 多线程   单线程   水来土掩   认知方式  

摘要： 有些人是单线程的,有些人是多线程的。看着都是人,本质很不一样。所谓多线程,就是能同时处理几件事。所谓单线程,就是一次只能做一件事。既然人当中既有单线程又有多线程,说明这两种工作模式各有好处.没有哪个被进化淘汰。总的来说,多线程重视效率,单线程重视效果。效率指的是单位时间内完成的工作量效果指的是最终结果。效率关心投入,效果只看结果。单线程这种工作方式本身,就是牺牲其余,只看结果。他被选定的目标摄了魂,其余万物熟视无睹不萦于心。他对在其线程中的人与事有绝对的忠诚,此时此刻值得绝对的信任。这与人品无关,只与认知方式有关。反过来看多线程,总是事先规划.留有冗余.从容不迫,兵来将挡,水来土掩.似乎一切尽在掌握。治世之良臣,往往是多线程。

关键词： 煤矿监控系统   监控分站   多线程安全   数据缓存   双缓存队列  

摘要： 以煤矿监控系统为平台,监控分站为设计对象,设计了带有多线程安全的双数据缓存技术,传感器数据帧进入队列存放后,监控分站对数据帧逐一进行解析处理后,封装成以太网数据包发送给中心站软件,另外考虑避免饥饿或死锁发生,设计的数据缓存技术加入了多线程安全保护。实际应用证明:该数据缓存队列软件架构清晰,占用内存小,易实现,提升了系统数据处理能力,解决了分站对中心站指令、传感器数据处理不及时、丢失等问题。