基于SGI服务器的Web平台越权访问技术的研究

越权访问是基于Web系统普遍存在的问题,也是一个非常难解决的问题。以SGI服务器构建的Web系统为例,通过理论分析和实例讨论来解决越权访问这一棘手的问题,最终达到将来能构建更安全的Web系统的目的。     

有向感知可充电传感器节点的动态激活策略

在采集环境能量供电的有向感知传感器网络中,节点的激活、休眠调度及感知方向选择关系到对目标点的覆盖和监测成功率.基于节点采集能量速度慢于耗能速度及采集能量速度快于耗能速度两种情况,设计了逐次贪婪节点激活算法SGA和逐次贪婪节点休眠算法SGI.SGA算法逐次将能够给系统带来最大覆盖率增益的感知节点分配给其对应的时隙及感知方向;在为所有感知节点在所有时隙选择最佳感知方向激活的基础上,SGI算法逐次选择令系统覆盖率损失最小的感知节点,令其在相应的时隙休眠.理论证明,SGA算法及SGI算法至少能获得最优激活调度算法50%的系统平均覆盖率性能,且将最大化系统覆盖率的NP难问题转化为简单的多项式时间方法.最后,仿真验证了SGA算法和SGI算法的性能.     

LPG-SGI系统发动机试验研究

研究了电喷车用LPG顺序喷射系统（即SGI系统）的有关特性，了解LPG－SGI系统在多种稳定转速和负荷下的发动机性能及排放特性，并与原发动机使用汽油燃料进行对比，装有LPG－SGI系统时代超人样车的排放满足国家现在实施的欧洲I号排放法规的要求。     

计算机三维动画对硬、软件的要求及创作过程

通过对国内外计算机三维动画创作技术应用的比较 ,介绍计算机硬件 (图形显示卡、图形工作站等 )的性能和工作方式以及应用软件 (3DSMAX、MAYA、SOFTIMGE、HUNIDE等 )的发展和三维动画的创作过程     

Exploring the performance of massively multithreaded architectures

We present a new scheme for evaluating the performance of multithreaded computers and demonstrate its application to the Cray MTA‐2 and XMT supercomputers. Our scheme is based on the concept of clock cycles per element, ${\cal C}$, plotted against both problem size and the number of processors. This scheme clearly shows if an implementation has achieved its asymptotic efficiency and is more general than (but includes) the commonly used speedup metric. It permits the discovery of any imperfections in both the software as well as the hardware, and is expected to permit a unified comparison of many different parallel architectures. Measurements on a number of well‐known parallel algorithms, ranging from matrix multiply to quicksort, are presented for the MTA‐2 and XMT and highlight some interesting differences between these machines. The performance of sequence alignment using dynamic programming is evaluated on the MTA‐2, XMT, IBM x3755 and SGI Altix 350 and provides a useful comparison of the capabilities of the Cray machines with more conventional shared memory architectures. Copyright © 2009 John Wiley & Sons, Ltd.     

实现影视制作网络资源共享的SGI与PC配置设计

在NFS系统原理的基础上，提出了一套SGI图像工作站与PC平台进行网络资源共享的高－低配置方案，设计了一套合理的三维动画工作流程，在不影响图像质量的前提下，缩短了工作时间，提高了三维动画的制作效率。     

油纸电容式套管的计算机辅助设计

介绍了应用ＳＧＩ工作站与Ｐ５８６ 微机, 建立不同的数据库, 对油纸电容式套管进行参数化制图的主要内容、特点及设计方法。     

Parallel bandwidth characteristics calculations for thin avalanche photodiodes on a SGI Origin 2000 supercomputer

An important factor for high‐speed optical communication is the availability of ultrafast and low‐noise photodetectors. Among the semiconductor photodetectors that are commonly used in today's long‐haul and metro‐area fiber‐optic systems, avalanche photodiodes (APDs) are often preferred over p‐i‐n photodiodes due to their internal gain, which significantly improves the receiver sensitivity and alleviates the need for optical pre‐amplification. Unfortunately, the random nature of the very process of carrier impact ionization, which generates the gain, is inherently noisy and results in fluctuations not only in the gain but also in the time response. Recently, a theory characterizing the autocorrelation function of APDs has been developed by us which incorporates the dead‐space effect, an effect that is very significant in thin, high‐performance APDs. The research extends the time‐domain analysis of the dead‐space multiplication model to compute the autocorrelation function of the APD impulse response. However, the computation requires a large amount of memory space and is very time consuming. In this research, we describe our experiences in parallelizing the code in MPI and OpenMP using CAPTools. Several array partitioning schemes and scheduling policies are implemented and tested. Our results show that the code is scalable up to 64 processors on a SGI Origin 2000 machine and has small average errors. Copyright © 2004 John Wiley & Sons, Ltd.     

Comparing the performance of MPICH with Cray's MPI and with SGI's MPI

The purpose of this paper is to compare the performance of MPICH with the vendor Message Passing Interface (MPI) on a Cray T3E‐900 and an SGI Origin 3000. Seven basic communication tests which include basic point‐to‐point and collective MPI communication routines were chosen to represent commonly‐used communication patterns. Cray's MPI performed better (and sometimes significantly better) than Mississippi State University's (MSU's) MPICH for small and medium messages. They both performed about the same for large messages, however for three tests MSU's MPICH was about 20% faster than Cray's MPI. SGI's MPI performed and scaled better (and sometimes significantly better) than MPICH for all messages, except for the scatter test where MPICH outperformed SGI's MPI for 1 kbyte messages. The poor scalability of MPICH on the Origin 3000 suggests there may be scalability problems with MPICH. Copyright © 2003 John Wiley & Sons, Ltd.