一种增强服务器高可用性的设计方法

首先简要介绍了HA(High Availability)的内容和工作原理,然后详细分析了HA的心跳数据格式和心跳流程,给出了一种增强服务器高可用性的设计方法,并在Unix操作系统Solaris上采用C 完成了HA模块开发.     

传统HA系统的终结者

传统HA系统已经完成了自己华丽的使命,可以寿终正寝了,即使你很念旧情,也不能阻挡Hypervisor HA的来袭。     

基于Dump/Load方法实现Sybase复制数据同步的研究

本文分析了Sybase复制服务器的基本原理，介绍了山东国税双机HA系统的结构，提出了通过Dump／Load方法实现两个ASE数据库之间数据复制同步的方法和详细步骤，并与BCP方法进行了比较。     

基于多HA部署的MIPv6网络服务可用性提升方法

移动IPv6是实现下一代互联网移动特性的核心技术,依赖于部署在家乡链路的家乡代理(HA)实现节点移动过程中的可寻址性.家乡链路的单一HA部署,将成为系统的单点故障隐患及性能瓶颈,难以保证系统服务可用性.为提升移动IPv6网络的系统服务可用性和系统性能,需要在家乡链路部署多HA,解决其单点故障问题,并有效均衡多家乡代理间的负载.文中研究移动IPv6网络多家乡代理部署方法,引入检测备份环对多HA间进行有效组织,基于此实现HA容错和负载均衡.多家乡代理采用单一HA映像以实现容错及负载均衡处理对移动节点的透明性,减小处理延迟和开销.     

ZigBee家庭自动化网络的测量与传感节点的设计与实现

ZigBee的家庭自动化(HA)网络是智能家居系统发展的一个方向.在对HA应用子集中的测量与传感簇的工作特性和属性报告机制进行详细分析后,给出了一种基于Z-Stack的符合HA规范的测量与传感类终端节点的设计方案.该方案,硬件结构采用模块化设计,配以不同的传感器模块实现不同类型物理量的测量.软件上,以Z-Stack协议栈为基础,通过建立新的ZCL应用来实现节点功能,并利用属性报告机制实现测量与传感的属性的传送.最后,以一光传感器节点设备为实例,进行了方案的验证.实践验证表明,该设计方案切实可行,适用于HA网络的测量与传感节点设备的设计.     

基于主动过载预防的移动IPv6家乡代理负载均衡

在移动IPv6网络中,为确保移动节点的可寻址性,提升网络系统的服务可用性和系统性能,有必要在家乡链路部署多HA,并有效平衡负载.提出了基于主动过载预防的多HA负载均衡方法.该方法通过主动地为移动注册请求动态选择最优HA,预防HA过载,而不同于原有方案仅仅基于被动的负载迁移的思路.所提方法引入动态加权负载评估算法,为负载均衡的实施提供最佳决策依据,采用负载切片机制减小信令开销.通过理论分析证明了提出的方法比原有各方法能够更有效地减小由于HA过载造成的移动注册失败率、平均注册延时,同时引入的系统开销更小,更显著地提升MIPv6网络系统服务的可用性和系统性能.     

基于HA结构的HLR系统容灾中心技术

文中分析了移动通信系统归属位置寄存器（HLR）中数据的一致性和安全性，认为应采用基于双PC服务器的外挂磁盘列阵的HA平台和N＋M模式的容灾中心系统来提高系统的可靠性。同时给出了大容量数据库的数据一致性和安全性解决方案。     

Mobile IPv6 Home Agent协议一致性测试集的设计与实现

描述了Mobile IPv6 HA协议一致性测试集设计与实现过程,说明该测试系统的测试方法和测试结构。通过测试实例介绍了测试集的形式化,并对一基于Linux平台的HA实现的测试结果进行了分析。     

校园一卡通双机热备系统设计实现对比解析

本文在校园一卡通双机热备技术选型开展了多方面的探讨,对当前常见的三种技术ROSE HA、ROSE MIRROR HA、Oracle RAC进行了对比分析,并根据实际情况给出了校园一卡通系统的数据存储安全实现方式的技术设计规划。通过校园一卡通系统的双机热备技术实施实现了数字化校园一卡通系统的高可靠性和高可用性,提高了一卡通系统运行的稳定性,确保了学校师生的正常学习生活。     

Cluster Computing集群计算

集群是一个广泛使用的术语，意思是通过软件和网络连接把独立的计算机结合成一个统一的系统。在最基础的层面上，当共同使用两个或多个计算机解决一个问题的时候，就可以把它看作一个集群系统。集群通常用于高可用性(HA)以获得高可靠性，或者用于高性能计算(HPC)，以提供单个计算机力所不及的强大计算能力。按照定义，计算机集群就是一组互连的计算机，作为一个并行计算机系统而共同工作。     

移动IPv6网络家乡代理容错方法研究

移动IPv6基于家乡代理的转发,实现节点移动过程中的可寻址性.提出主动检测和迁移的家乡代理容错方法,通过在家乡代理之间设计环状检测和备份链,使家乡代理之间相互检测失效情况的发生;所有注册信息在家乡链路上仅备份一次;检测到失效后,有效家乡代理自动地暂时接管失效家乡代理的工作,并主动通告给相关移动节点;移动节点收到家乡代理失效信息后,主动启动恢复过程.给出了实现该方法的数据结构和容错算法,描述了具体的容错处理过程.通过理论分析证明了该方法比协议标准中的方法具有更小的容错时间和信令开销,特别是在移动节点的移动频率较慢的情况下更是如此.     

Homology modeling study toward identifying structural properties in the HA2 B-loop that would influence the HA1 receptor-binding site

Influenza hemagglutinin (HA) consists of a fibrous globular stem (HA2) inserted into the viral membrane supporting a globular head (HA1). HA1 receptor-binding has been hypothesized to be structurally correlated to the HA2 B-loop, however, this was never fully understood. Here, we elucidated the structural relationship between the HA2 B-loop and the HA1 receptor-binding site (RBS). Throughout this study, we analyzed 2486 H1N1 HA homology models obtained from human, swine and avian strains during 1976–2012. Quality of all homology models were verified before further analyses. We established that amino acid residue 88₂ is putatively strain-conserved and differs in the human (K88₂), swine (H88₂) and avian (N88₂) strains. Moreover, we observed that the amino acid at residue 88₂ and, similarly, its orientation has the potential to influence the HA1 RBS diameter measurements which we hypothesize may consequentially affect influenza H1N1 viral infectivity, immune escape, transmissibility, and evolution.     

淹水厌氧条件下腐殖酸对红壤中铁异化还原过程的影响

采用室内培养实验,观测淹水厌氧条件下分别添加及共同添加葡萄糖和不同制备来源的腐殖酸,对红壤中铁的异化还原作用的影响.结果表明,红壤单独培养条件下,Fe(Ⅱ)浓度培养前后没有发生变化.添加葡萄糖促进了铁的异化还原,培养至12 d其Fe(Ⅱ)浓度为培养前的25倍.腐殖酸不能作为电子供体促进铁的异化还原,单独添加时红壤中Fe(Ⅱ)浓度没有发生变化,而同时添加葡萄糖情况下,培养前期促进而后期减弱铁的异化还原,其Fe(Ⅱ)浓度增幅仅为单独添加葡萄糖处理的35%.腐殖酸的浓度对红壤中铁的异化还原作用有影响,浓度为2.00 g/kg时培养前期促进而后期减弱铁的异化还原,低浓度时（0.20和0.02 g/kg）影响很小.不同制备来源的腐殖酸对红壤中铁异化还原过程的影响不同.培养前期,从山西大同风化煤(HAs)、河南巩县褐煤(HAh)和云南昆明滇池底泥(HAk)中提取的腐殖酸都促进了红壤中铁的异化还原;培养后期,HAk依然发挥促进作用,其Fe(Ⅱ)浓度始终高于G处理,而添加HAs和HAh的处理培养至7 d Fe(Ⅱ)仅为单独添加葡萄糖处理的14%和25%,减弱了铁的异化还原.     

Fault-tolerant design for wide-area Mobile IPv6 networks

Mobile IPv6 provides the mobility management for IPv6 protocol. To establish a reliable Mobile IPv6 network, fault tolerance should be also considered in the network design. This paper presents an efficient fault-tolerant approach for Mobile IPv6 networks. In the proposed approach, if a failure is detected in the home agent (HA) of a mobile node, a preferable survival HA is selected to continuously serve the mobile node. The preferable survival HA is the HA that does not incur failure and is neighboring the current location of the mobile node. The proposed approach is based on the preference of each mobile node to achieve the fault tolerance of the HA. Finally, we perform simulations to evaluate the performance of the proposed approach.     

On-chip HA/SSCP for the detection of hereditary haemochromatosis

Microfluidics provides a promising tool for meeting the growing demand for high-throughput and low-cost mutation detection technology. With conventional instrumentation, this need is often addressed by the combination of the single-strand conformation polymorphism (SSCP) and heteroduplex analysis (HA) methods. This paper describes an effective microchip-based method to analyse the three most commonly tested gene mutations (C282Y, H63D, and S65C) associated with hereditary haemochromatosis by simultaneously performing microchip-based SSCP and HA, directly upon samples of polymerase chain reaction (PCR) product. We have increased the sensitivity of mutation detection considerably by adapting and combining SSCP with HA. We are able to perform the analysis within several minutes by avoiding off-chip sample preparation steps for SSCP and HA (apart from the PCR). The most important mutation in the screening of populations for this disease is the C282Y mutation and this mutation has not previously been detected with methods of HA/SSCP suitable for microchip implementation. This is, to the best of our knowledge, the first microchip-based test applying SSCP and HA for all three of the most common HFE mutations.     

Fault tolerance for home agents in mobile IP

In the conventional IP protocol, whenever a mobile device moves to a different network, it must change its IP address to communicate with other nodes in the Internet. Mobile IP protocol keeps mobile nodes online without changing their IP addresses while changing the attachment points. The packets destined to mobile nodes (MN) are relayed by their home agents (HA). However, once the only one HA fails, all MNs managed by the HA will not receive packets normally. In the paper, we propose a novel protocol with multiple mobile agents (MA) where only double mobility bindings are maintained in the whole system. When an HA is failed, its backup HA can take over it in a short time without fetching the bindings from other places. Besides, we also consider the load balancing between these HAs during HA takeover and recovery. Through the simulation and analyses, we found that our method has less registration overheads, better MN-scalability, less sensitivity on MN mobility, more fault-tolerance robustness, and less takeover time than others.     

Hidden annotation for image retrieval with long-term relevance feedback learning

Hidden annotation (HA) is an important research issue in content-based image retrieval (CBIR). We propose to incorporate long-term relevance feedback (LRF) with HA to increase both efficiency and retrieval accuracy of CBIR systems. The work contains two parts. (1) Through LRF, a multi-layer semantic representation is built to automatically extract hidden semantic concepts underlying images. HA with these concepts alleviates the burden of manual annotation and avoids the ambiguity problem of keyword-based annotation. (2) For each learned concept, semi-supervised learning is incorporated to automatically select a small number of candidate images for annotators to annotate, which improves efficiency of HA.     

Extended state observer-based motion synchronisation control for hybrid actuation system of large civil aircraft

Hybrid actuation system with dissimilar redundant actuators, which is composed of a hydraulic actuator (HA) and an electro-hydrostatic actuator (EHA), has been applied on modern civil aircraft to improve the reliability. However, the force fighting problem arises due to different dynamic performances between HA and EHA. This paper proposes an extended state observer (ESO)-based motion synchronisation control method. To cope with the problem of unavailability of the state signals, the well-designed ESO is utilised to observe the HA and EHA state variables which are unmeasured. In particular, the extended state of ESO can estimate the lumped effect of the unknown external disturbances acting on the control surface, the nonlinear dynamics, uncertainties, and the coupling term between HA and EHA. Based on the observed states of ESO, motion synchronisation controllers are presented to make HA and EHA to simultaneously track the desired motion trajectories, which are generated by a trajectory generator. Additionally, the unknown disturbances and the coupling terms can be compensated by using the extended state of the proposed ESO. Finally, comparative simulation results indicate that the proposed ESO-based motion synchronisation controller can achieve great force fighting reduction between HA and EHA.     

HA和HYP分子内质子传递模式差异的理论研究

采用量子化学从头算的计算方法,研究了竹红菌素(HA)4种异构体发生分子内质子传递(IPT)的过程。结果表明,在竹红菌素分子内质子传递的过程中不会发生碳骨架结构的变化,这与之前文献中的猜测是不一致的,利用CIS和TD方法计算研究了竹红菌素激发态分子内质子传递的过程.结果表明,竹红菌素顺式结构的IPT过程是一个～10ps的瞬态过程,而竹红菌素反式结构的IPT过程则是一个～50～250ps的瞬态过程.根据计算结果我们对竹红菌素和金丝桃蒽酮分子内质子传递模式之间的差异做出了初步的解释.