Comparison of two novel MRAS based strategies for identifying parameters in permanent magnet synchronous motors

Two model reference adaptive system (MRAS) estimators are developed for identifying the parameters of permanent magnet synchronous motors (PMSM) based on the Lyapunov stability theorem and the Popov stability criterion, respectively. The proposed estimators only need online measurement of currents, voltages, and rotor speed to effectively estimate stator resistance, inductance, and rotor flux-linkage simultaneously. The performance of the estimators is compared and verified through simulations and experiments, which show that the two estimators are simple, have good robustness against parameter variation, and are accurate in parameter tracking. However, the estimator based on the Popov stability criterion, which can overcome parameter variation in a practical system, is superior in terms of response speed and convergence speed since there are both proportional and integral units in the estimator, in contrast to only one integral unit in the estimator based on the Lyapunov stability theorem. In addition, the estimator based on the Popov stability criterion does not need the expertise that is required in designing a Lyapunov function.     

LR分析的教学法探讨

LR分析法是编译程序语法分析中最常用且有效的自下而上的分析方法,理论较完善,适用于大多数上下文无关语言的分析。本文主要探讨LR分析的教学方法,采用"启发+关联式"教学法,引导学生理解LR分析的内涵。     

基于HT46RU232的全自动体检仪

设计了一种全自动体检仪,高效、精确、实时地实现常规体检项目的自动测量.以HT46RU232单片机为下位机,以LabVIEW软件开发的程序为上位机.该体检仪高效、精确、实时地实现了常规体检项目的自动测量,并可根据需要输出相应的电子和纸质报告,还具有防背诵作弊、防盗版功能.此设计是对传统常规体检的一种廉价、高效的替代方案,...     

一种共享存储视频服务器集群的请求调度策略

在VOD服务器集群中,对用户服务请求的合理调度是提高集群整体性能的关键技术之一.本文针对共享存储结构下的服务器机群,在请求调度算法LoadCache-rep基础上进行改进,提出一种基于视频节目点播集中度的调度策略,该策略通过将相近的点播请求调度至相同服务器上以充分利用服务器的缓存机制,同时兼顾均衡各服务器间的负载.并根据实时负载变化对请求进行迁移以消除VCR操作对负载分布的影响.仿真试验表明,该策略能有效提高视频服务器集群的运行性能.     

Highly Optimized Code Generation for Stencil Codes with Computation Reuse for GPUs

Computation reuse is known as an effective optimization technique. However, due to the complexity of modern GPU architectures, there is yet not enough understanding regarding the intriguing implications of the interplay of computation reuse and hardware specifics on application performance. In this paper, we propose an automatic code generator for a class of stencil codes with inherent computation reuse on GPUs. For such applications, the proper reuse of intermediate results, combined with careful register and on-chip local memory usage, has profound implications on performance. Current state of the art does not address this problem in depth, partially due to the lack of a good program representation that can expose all potential computation reuse. In this paper, we leverage the computation overlap graph (COG), a simple representation of data dependence and data reuse with “element view”, to expose potential reuse opportunities. Using COG, we propose a portable code generation and tuning framework for GPUs. Compared with current state-of-the-art code generators, our experimental results show up to 56.7 % performance improvement on modern GPUs such as NVIDIA C2050.     

金标试纸条的尿素酶快速定量检测仪研制

研制了一种基于CMOS传感器的胶体金免疫层析试纸条的尿素酶定量检测系统。该系统由硬件和软件两部分组成,硬件部分利用CMOS传感器和条码扫描仪来获取检测图像和病人的个人信息。软件部分除了实现免疫层析试纸条光信号的分析和诊断还实现病人信息采集和建立病人信息数据库等关键功能。该软件采用了k-means聚类算法,实现采集图像的精准分析。通过检测200例尿素酶样品试纸条,验证了设备的稳定性和准确性。该系统体积小、便携性强且具有优秀的续航能力,可用于长时间的临床、野外和社区体检。     

Robust State Estimation for Delayed Complex-Valued Neural Networks

This paper is concerned with the state estimation problem for the uncertain complex-valued neural networks with time delays. The parameter uncertainties are assumed to be norm-bounded. Through available output measurements containing nonlinear Lipschitz-like terms, we aim to design a state estimator to estimate the complex-valued network such that, for all admissible parameter uncertainties and time delay, the dynamics of the error-state system is guaranteed to be globally asymptotically stable. In addition, the case that there are no parameter uncertainties is also considered. By utilizing the Lyapunov functional method and matrix inequality techniques, some sufficient delay-dependent criteria are derived to assure the existence of the desired estimator gains. Finally, two numerical examples with simulations are presented to demonstrate the effectiveness of the proposed estimation schemes.     

一种高灵敏度FBG加速度传感器设计与仿真

采用悬臂梁与垫高块结构,设计了一种高灵敏度的光纤光栅加速度传感器,光栅栅区两端固定在悬臂梁与垫高块之间,提高了传感器的灵敏度,避免了出现啁啾或多峰现象,推导了设计计算的力学模型;对传感器进行了过载安全保护设计、光栅预拉伸设计等;采用有限元分析计算得出了悬臂梁应变分布情况及6阶固有频率,证明分析结果与设计计算吻合。     

无线寻呼系统的设计与实现

结合寻呼系统的特点,对寻呼系统的总体设计和功能模块进行详细的论述,同时阐明了无线寻呼的基本过程,并对保证寻呼系统的高效性,提高寻呼系统可靠性,稳定性所采取的 全面地研究。     

有限元的未来是多物理场耦合

随着计算机技术的迅速发展,在工程领域中,有限元分析(FEA)越来越多地用于仿真模拟,来求解真实的工程问题。这些年来,越来越多的工程师、应用数学家和物理学家已经证明这种采用求解偏微分方程(PDE)的方法可以求解许多物理现象,这些偏微