Stability margins of nonlinear optimal regulators with nonquadratic performance criteria involving cross-weighting terms

In this paper we derive guaranteed gain, sector, and disk margins for nonlinear optimal and inverse optimal regulators that minimize a nonlinear-nonquadratic performance criterion involving cross-weighting terms. Specifically, sufficient conditions that guarantee gain, sector, and disk margins are given in terms of the state, control, and cross-weighting nonlinear-nonquadratic weighting functions. The proposed results provide a generalization of the “meaningful” inverse optimal nonlinear regulator stability margins as well as the classical linear-quadratic optimal regulator gain and phase margins.     

RAID系统的结构化模型、

分析RAID系统组成,按功能分成target,内存管理,RAID管理和initiator四个部分,对各个部分的功能简单说明。     

基于ASPED模型的高性能Web服务器

主要内容是关于当设计高性能Web服务器时,如何解决快速CPU处理能力和慢速磁盘访问之间的矛盾。前半部分主要讨论现有Web服务器模型的优缺点,后半部分描述了异步单进程事件驱动（ASPED）模型及其实现。ASPED是一个综合SPED,AMPED优势和异步I／O思想的Web服务器模型。为证明该模型的先进性,据此编码了一个Web服务器Jaguar,经SpecWeb99测试,Jaguar的性能要比基于AMPED模型的Web服务器Flash的性能最多好20％。     

硬盘信息卸载系统的研制

讨论了当硬盘驱动器出现故障后,存储在硬盘上信息的保密问题;给出了一种将故障硬盘上存储信息进行卸载处理的方案。     

表征PAN纤维和炭纤维微细结构的HRTEM样品制备方法

为用高分辨透射电子显微术(HRTEM)表征聚丙烯腈(PAN)纤维和炭纤维的微细结构，从纤维性能出发，探讨研碎、离子束减薄和超薄生物切片三种制备方法及其工艺步骤，结合实验结果，对比了三种制备方法的原理、优缺点，提出了制备方法的适用范围和选择原则，并推断适于表征预氧化纤维微细结构的样品制备方法。与生物样品的制备方法类似，把超薄生物切片法引入到纤维材料HRTEM样品制备领域，为系统研究炭纤维微细结构的演变提供了线索。     

硬盘磁头故障诱发原因研究

硬盘的磁头一旦发生故障，硬盘上的数据就会全部丢失，会给用户带来较大的数据或经济上的损失．本文分析了磁头碰撞、磁头与盘片粘连、磁头臂与磁头臂支撑架粘连、磁头污染等硬盘磁头故障的诱发原因，并针对故障产生原因，提出了通过改进硬盘设计来减少磁头故障的方法．     

生成圆弧的等距线约束方法及其应用

栅格圆弧的生成算法在计算机图形学和图像处理中有着大量的应用．一条曲线一定位于该线两侧的两条到该线距离足够小的等距线之间，或认为该曲线受其两侧的两条等距线的约束．本文从真实圆弧曲线受其两侧的等距圆的约束出发，提出一种生成栅格圆弧的等距线约束算法，并分析了该算法的精度．其优点是可单方向连续生成圆弧，且生成的两个相邻栅格圆之间不会有空隙或重叠，因此可直接用于圆域有关的图形生成和栅格点扩散搜索．本文最后研究了该方法在栅格圆环、圆盘及球面、球等生成及Euclid距离变换中的应用．     

Data partitioning and load balancing in parallel disk systems

Parallel disk systems provide opportunities for exploiting I/O parallelism in two possible ways, namely via inter-request and intra-request parallelism. In this paper, we discuss the main issues in performance tuning of such systems, namely striping and load balancing, and show their relationship to response time and throughput. We outline the main components of an intelligent, self-reliant file system that aims to optimize striping by taking into account the requirements of the applications, and performs load balancing by judicious file allocation and dynamic redistributions of the data when access patterns change. Our system uses simple but effective heuristics that incur only little overhead. We present performance experiments based on synthetic workloads and real-life traces. Received May 17, 1994 / Accepted June 9, 1997     

Handling Updates and Crashes in VoD Systems

Though there have been several recent efforts to develop disk based video servers, these approaches have all ignored the topic of updates and disk server crashes. In this paper, we present a priority based model for building video servers that handle two classes of events: user events that could include enter, play, pause, rewind, fast-forward, exit, as well assystem events such as insert, delete, server-down, server-up that correspond to uploading new movie blocks onto the disk(s), eliminating existing blocks from the disk(s), and/or experiencing a disk server crash. We will present algorithms to handle such events. Our algorithms are provably correct, and computable in polynomial time. Furthermore, we guarantee that under certain reasonable conditions, continuing clients experience jitter free presentations. We further justify the efficiency of our techniques with a prototype implementation and experimental results.     

硬磁盘物理级读／写控制方法及其应用

分析目前硬盘开放性结构的缺陷及由此对系统和应用安全性造成的多种危害和潜在威胁。