怎样保证网络的高可用性

一、网络高可用性应用分析 目前,保证网络高可用性一般是从两个方面同时入手,即硬件备份和软件容错。硬件备份需要消耗大量的备份硬件设备,大大提高了组网投资。软件容错只需要性能较高、功能全面和管理简单的系统即可,而且既使硬件备份齐全,也需要较好的容错软件管理备份系统,从而保证网络系统在工作运行中的可用性和稳定性。所以从这个方面来讲,网络系统的高可用性需要从硬件配置到软件选用全面考虑和合理采用。

浅论如何形成工程质量的保证网

工程质量是工程之本，工程项目招标投标、政府监督、社会监理、企业自检形成了质量管理的大网，企业管理水平的提高，依靠技术进步，机械化、自动化程度及人员素质的提高又形成了质量管理的细网，这样工程质量才会进一步提高。

中国公用计算机互联网骨干网——CHINANET

项目概述 中国公用计算机互联网骨干网CHINANET是中国第一个由国人自己设计、建设及运营管理的大型公用计算机互联网,是以TCP/IP Internetworking技术覆盖全中国所有省份,以提供公共服务为主要目的,在全国范围内实现用户全透明漫游和统一的中英文用户界面的大型数据通讯网络。整个网络具有充足的高速路径来保证网络的高度可靠性。

QUALITY ASSURANCE INFORMATION SYSTEM FOR AGILE MANUFACTURING

The customer driven dynamic global market and geographical distribution of collaborating partners bring new challenges to the development of quality assurance information system (QAIS) for agile manufacturing. With recent dramatic advances in information technology, firstly the requirements of QAIS are examined in agile manufacturing environment, then a new implementation framework of a distributed QAIS is presented, where a deve loping environment of QAIS is established and some critical techniques are studied. Finally a prototype system based on world wide web (WWW) is accomplished.

专家点评

随着信息化的发展,信息技术的不断向前迈进,用户对信息的应用要求也越来越高,这就决定了一些企业原有的网络已经满足不了应用的需求,开始了必要的网络升级。北京石油化工工程公司网络升级就是在这种情况下进行的,给我们提供了一些参考。 主干技术选择千兆以太网 对于一个网络来讲,网络平台的技术选择尤为重要,只有平台选择先进的网络技术才能保证网络系统技术的先进性,而网络技术的选择主要是主干技术的选择。现今能适合作主干技术的无疑只有ATM和千兆以太网,

Development and Challenge of HIV/AIDS Testing Laboratory Network and Quality Assurance System in China

This paper describes the development and challenge of HIV/AIDS testing laboratory network and quality assurance system in China. At present,the HIV/AIDS testing laboratories includes three classes,the National AIDS Reference Laboratory,HIV/AIDS confirmatory laboratories and HIV/AIDS screening laboratories. All of them are accredited by the health authorities,and each class of laboratories take charge of their function strictly according to the "National Management of HIV/AIDS Detection (2006)". A complete quality assurance and quality control system for HIV/AIDS testing has been developed,which includes technical training,strict laboratory monitoring and approval,examination or proficiency testing on HIV/AIDS detection,and quality evaluation and supervision of HIV/AIDS diagnostic kits. Besides conduct the routine anti-HIV antibody test,more and more laboratories began to conduct other tests,such as CD4+ T lymphocyte cell counting,HIV viral load,HIV DNA PCR,genotyping,drug resistance,and HIV-1 recent infection test. The primary challenges faced by the HIV/AIDS testing laboratory network are in the areas of laboratory management and quality control. For example,the provincial PT program is inefficient,the internal quality control is conducted perfunctorily,personnel training can not met the needs of the workplace,which need to be improved.

Lightweight Mutual Authentication Scheme for Protecting Identity in Insecure Environment

Many improved authentication solutions were put forward, on purpose of authenticating more quickly and securely.However, neither the overuse of hash function,or additional symmetric encryption, can truly increase the overall security. Instead,extra computation cost degraded the performance.They were still vulnerable to a variety of threats, such as smart card loss attack and impersonation attack, due to hidden loopholes and flaws. Even worse, user's identity can be parsed in insecure environment, even became traceable. Aiming to protect identity, a lightweight mutual authentication scheme is proposed. Redundant operations are removed,which make the verification process more explicit. It gains better performance with average cost compared to other similar schemes.Cryptanalysis shows the proposed scheme can resist common attacks and achieve user anonymity.Formal security is further verified by using the widely accepted Automated Validation of Internet Security Protocols and Applications(AVISPA) tool.

On the analysis of the construction of the quality guarantee system of web based College English teaching

With the quick development of the reform of College English teaching, web based College English teaching is used and generalized in every institution of higher education. However, more attention should be paid to the teaching quality to develop this web based College English teaching model. Therefore, the construction of the quality guarantee system is of major significance to promote the effective design of web based College English course system and improve the quality of web based College English teaching.

HiQoS:An SDN-Based Multipath QoS Solution

Today's Internet architecture provides only "best effort" services,thus it cannot guarantee quality of service(QoS) for applications.Software Defined Network(SDN)is a new approach to computer networking that separates control plane and forwarding planes,and has the advantage of centralized control and programmability.In this paper,we propose HiQoS that provides QoS guarantees using SDN.Moreover,HiQoS makes use of multiple paths between source and destination and queuing mechanisms to guarantee QoS for different types of traffic.Experimental results show that our HiQoS scheme can reduce delay and increase throughput to guarantee QoS.Very importantly,HiQoS recovers from link failure very quickly by rerouting traffic from failed path to other available path.

QoS Guaranteed Pre-Pushing Scheme in Peer-Assisted Streaming Network

In peer-assisted streaming network, service provider needs to pre-pushing resources to some users for caching. This scheme can increase the resource availability. In traditional strategy, in order to guarantee the user＇s quality of service （QoS）, the pre-pushing action can only start at the time point that the certain user has not used the computer for more than 20 minutes. If the user comes back, the pre-pushing action will be stopped. We claim that this is not an efficient scheme. In this paper, we propose a novel pre-pushing scheme to improve the pre-pushing efficiency, while meeting the user＇s QoS requirements. The basic idea is using the user＇s available bandwidth as much as possible in the condition of meeting the user＇s QoS requirements. Then we design an available bandwidth calculating strategy. The numerical simulation demonstrates that our proposed scheme outperforms the traditional one.

A novel approach for agent ontology and its application in question answering

The information integration method of semantic web based on agent ontology(SWAO method) was put forward aiming at the problems in current network environment,which integrates,analyzes and processes enormous web information and extracts answers on the basis of semantics. With SWAO method as the clue,the following technologies were studied:the method of concept extraction based on semantic term mining,agent ontology construction method on account of multi-points and the answer extraction in view of semantic inference. Meanwhile,the structural model of the question answering system applying ontology was presented,which adopts OWL language to describe domain knowledge from where QA system infers and extracts answers by Jena inference engine. In the system testing,the precision rate reaches 86%,and the recalling rate is 93%. The experimental results prove that it is feasible to use the method to develop a question answering system,which is valuable for further study in more depth.

A Location Privacy Preserving Solution to Resist Passive and Active Attacks in VANET

Existing location privacy- preserving methods, without a trusted third party, cannot resist conspiracy attacks and active attacks. This paper proposes a novel solution for location based service （LBS） in vehicular ad hoc network （VANET）. Firstly, the relationship among anonymity degree, expected company area and vehicle density is discussed. Then, a companion set F is set up by k neighbor vehicles. Based on secure multi-party computation, each vehicle in V can compute the centroid, not revealing its location to each other. The centroid as a cloaking location is sent to LBS provider （P） and P returns a point of interest （POI）. Due to a distributed secret sharing structure, P cannot obtain the positions of non-complicity vehicles by colluding with multiple internal vehicles. To detect fake data from dishonest vehicles, zero knowledge proof is adopted. Comparing with other related methods, our solution can resist passive and active attacks from internal and external nodes. It provides strong privacy protection for LBS in VANET.