基于RDP算法的RAID6实现

正确高效的RAID6算法是RAID6磁盘阵列系统可靠运作的保障,算法的实现效率将直接影响整个系统的性能。笔者首先对RAID6的现有可行算法进行了分析,然后详细介绍了基于RDP算法的RAID6实现,最后用权威的Benchmark对该实现机制做出评估。     

ZFS文件系统中双容错编码性能的研究

ZFS是Sun推出的一款革新性的文件系统,它支持用户构建镜像以及单容错/双容错的软Raid。其双容错编码方案采用的是Reed-Solomon编码(RS码)。由于RS码是基于有限域运算,编码/解码时间复杂性差是其根本性的缺陷。ZFS对写操作的处理采用的是聚合后追加的方式而非传统的覆盖方式,每次写操作都会进行一次编码计算。因此,编码计算性能是影响文件系统整体性能的重要因素之一。本文的工作是将RDP这一基于奇偶校验的双容错编码与ZFS相结合,替代Reed-Solomon编码,以优化文件系统写操作的性能。我们设计了Cache优化的RDP编码算法,在ZFS中进行了实现,并通过实验验证了这一方法的有效性。     

RDP对SEBS/IFR共混体系性能的影响

向苯乙烯-乙烯/丁烯-苯乙烯嵌段共聚物(SEBS)/膨胀型阻燃剂(IFR)共混体系中加入间苯二酚双(二苯基)磷酸酯(RDP),通过扫描电镜、热失重分析仪和万能材料试验机等研究了RDP对SEBS/IFR共混体系相容性以及阻燃效率与力学性能的影响.当加入2％的RDP时,由于体系可能产生弱氢键,拉伸强度由6.665 MPa提高至6.773 MPa,但随着RDP含量的增加,体系的拉伸强度会明显下降,这主要由于RDP对于体系中SEBS的增塑作用.高压毛细管测试结果表明,当RDP含量大于6％时,体系黏度下降十分明显,利于体系加工流动性.随着RDP的加入,SEBS/IFR共混体系的热分解温度由最初的239℃提高至255℃并且趋于稳定,残炭率由13.28％提高至19.89％.扫描电镜测试结果显示,RDP可以通过“包覆”阻燃剂颗粒提高SEBS/IFR共混体系的相容性.     

一种RDP协议安全性改进方法

Windows系列服务器是目前最广泛使用的服务器之一．在许多情况下需要远程访问这些服务器的应用和信息．为了满足这些需要，微软设计开发了远程桌面协议（简称RDP）．分析了RDP协议及其多个实现产品的特性，特别是安全方面的特性，提出了集成实现SSL（TLS）与RDP的方案以增强其安全性，保证在Internet环境下的安全工作，并给出了实现方法，测试和分析了其性能．     

网络新应用-Windows 2000终端服务

终端服务是在Windows 2000 Server产品系列中提供的一种技术，用以在一个远端的Windows　2000　Server上执行应用程序或进行相应的管理工作。本文介绍了终端服务的具体实现模式、相应组件、许可证发放机制，并给出在具体环境中应用时对应用程序的优化策略。     

A fuzzy logic for the revised drastic product <Emphasis Type="Italic">t</Emphasis>-norm

From the ordinal sum theorem for t-subnorms, Jenei introduced a new left-continuous t-norm (called RDP t-norm) by revising the drastic product t-norm. In this paper, propositional and predicate calculi generated by RDP t-norm and its residuum are introduced and the corresponding formal systems RDP and RDP∀, which are schematic extensions of Esteva and Godo’s MTL and MTL∀, respectively, are presented and the standard completeness for RDP and RDP∀ are proved. In addition, a new formula defining the standard disjunctive in RDP was given In the original version of this article, part of it seemed to be text from a previously published article by other authors. This was not so and the author would like to make clear that he was quoting from earlier work of his own in comparison to the work of the other authors. To facilitate this, it was decided that this addendum should be made available.     

修正的RDP逻辑系统中子代数的广义重言式理论

讨论了修正的RDP逻辑系统中序稠密子代数的广义重言式理论,并利用可达广义重言式概念和[α-]矛盾式概念在[RDP]的序稠密子代数中给出[F(S)]关于[～]同余的一个分划。     

桌面虚拟化技术研究与应用

主要介绍桌面虚拟化技术的现状,虚拟化关键技术和系统解决方案。详细比较了桌面虚拟化的2个主要技术：系统虚拟化技术和远程登录协议,比较了主流产品的特征与特点,最后,讨论了系统部署和实施过程中需要注意的问题和发展趋势。     

Genome-Wide Association Study Identifies a Rice Panicle Blast Resistance Gene,Pb2, Encoding NLR Protein

Rice blast is one of the main diseases in rice and can occur in different rice growth stages. Due to the complicated procedure of panicle blast identification and instability of panicle blast infection influenced by the environment, most cloned rice resistance genes are associated with leaf blast. In this study, a rice panicle blast resistance gene, Pb2, was identified by genome-wide association mapping based on the panicle blast resistance phenotypes of 230 Rice Diversity Panel 1 (RDP1) accessions with 700,000 single-nucleotide polymorphism (SNP) markers. A genome-wide association study identified 18 panicle blast resistance loci (PBRL) within two years, including 9 reported loci and 2 repeated loci (PBRL2 and PBRL13, PBRL10 and PBRL18). Among them, the repeated locus (PBRL10 and PBRL18) was located in chromosome 11. By haplotype and expression analysis, one of the Nucleotide-binding domain and Leucine-rich Repeat (NLR) Pb2 genes was highly conserved in multiple resistant rice cultivars, and its expression was significantly upregulated after rice blast infection. Pb2 encodes a typical NBS-LRR protein with NB-ARC domain and LRR domain. Compared with wild type plants, the transgenic rice of Pb2 showed enhanced resistance to panicle and leaf blast with reduced lesion number. Subcellular localization of Pb2 showed that it is located on plasma membrane, and GUS tissue-staining observation found that Pb2 is highly expressed in grains, leaf tips and stem nodes. The Pb2 transgenic plants showed no difference in agronomic traits with wild type plants. It indicated that Pb2 could be useful for breeding of rice blast resistance.     

一种低单盘故障恢复开销的局部修复码

如今随着存储系统规模的扩大和廉价磁盘的大量使用,单一磁盘故障在存储系统中发生故障的概率也不断上升。而在基于RDP编码的阵列存储系统中,恢复单个故障磁盘,需要读取全部的剩余数据磁盘,读取开销大,故障恢复时间长。而故障时间长就会导致系统在恢复过程中出错的概率增大,影响系统整体的稳定性。为进一步降低单个磁盘故障恢复的读取开销,减少恢复时间,提升存储系统可靠性,提出一种局部修复RDP码,通过增加一个局部冗余列来减少故障恢复时需要读取的数据量。实验结果表明改进方法在降低读取开销和减少恢复时间方面相对于传统的RDP单盘故障恢复方法有明显提高,并且能够恢复75%的三盘故障情况。