Internet环境下“分布式智能决策支持系统生成器”Browser/Multi-Server结构的研究

针对当前的Internet环境，文章提出了一种新的分布式智能决策支持系统生成器的结构，并着重阐述了IDSSG的这种结构如何在Internet环境下实现。

An efficient hash-based authenticated key agreement scheme for multi-server architecture resilient to key compromise impersonation

During the past decade,rapid advances in wireless communication technologies have made it possible for users to access desired services using hand-held devices.Service providers have hosted multiple servers to ensure seamless online services to end-users.To ensure the security of this online communication,researchers have proposed several multi-server authentication schemes incorporating various cryptographic primitives.Due to the low power and computational capacities of mobile devices,the hash-based multi-server authenticated key agreement schemes with offline Registration Server(RS)are the most efficient choice.Recently,Kumar-Om presented such a scheme and proved its security against all renowned attacks.However,we find that their scheme bears an incorrect login phase,and is unsafe to the trace attack,the Session-Specific Temporary Information Attack(SSTIA),and the Key Compromise Impersonation Attack(KCIA).In fact,all of the existing multi-server authentication schemes(hash-based with offline RS)do not withstand KCLA.To deal with this situation,we propose an improved hash-based multi-server authentication scheme(with offline RS).We analyze the security of the proposed scheme under the random oracle model and use the t4Automated Validation of Internet Security Protocols and Applications''(AVISPA)tool.The comparative analysis of communication overhead and computational complexity metrics shows the efficiency of the proposed scheme.

A Secure Three-Factor Authenticated Key Agreement Scheme for Multi-Server Environment

Multi-server authenticated key agreement schemes have attracted great attention to both academia and industry in recent years.However,traditional authenticated key agreement schemes in the single-server environment are not suitable for the multi-server environment because the user has to register on each server when he/she wishes to log in various servers for different service.Moreover,it is unreasonable to consider all servers are trusted since the server in a multi-server environment may be a semi-trusted party.In order to overcome these difficulties,we designed a secure three-factor multi-server authenticated key agreement protocol based on elliptic curve cryptography,which needs the user to register only once at the registration center in order to access all semi-trusted servers.The proposed scheme can not only against various known attacks but also provides high computational efficiency.Besides,we have proved our scheme fulfills mutual authentication by using the authentication test method.

Efficient Hierarchical Multi-Server Authentication Protocol for Mobile Cloud Computing

With the development of communication technologies,various mobile devices and different types of mobile services became available.The emergence of these services has brought great convenience to our lives.The multi-server architecture authentication protocols for mobile cloud computing were proposed to ensure the security and availability between mobile devices and mobile services.However,most of the protocols did not consider the case of hierarchical authentication.In the existing protocol,when a mobile user once registered at the registration center,he/she can successfully authenticate with all mobile service providers that are registered at the registration center,but real application scenarios are not like this.For some specific scenarios,some mobile service providers want to provide service only for particular users.For this reason,we propose a new hierarchical multi-server authentication protocol for mobile cloud computing.The proposed protocol ensures only particular types of users can successfully authenticate with certain types of mobile service providers.The proposed protocol reduces computing and communication costs by up to 42.6%and 54.2%compared to two superior protocols.The proposed protocol can also resist the attacks known so far.

Weaknesses of a Dynamic ID Based Remote User Authentication Protocol for Multi-Server Environment

Currently, smart card based remote user authentication schemes have been widely adopted due to their low cost and convenient portability. With the purpose of using various different internet services with single registration and to protect the users from being tracked, various dynamic ID based multi-server authentication protocols have been proposed. Recently, Li et al. proposed an efficient and secure dynamic ID based authentication protocol using smart cards. They claimed that their protocol provides strong security. In this paper, we have demonstrated that Li et al.’s protocol is vulnerable to replay attack, denial of service attack, smart card lost attack, eavesdropping attack and server spoofing attacks.

Cryptanalysis of Two Dynamic Identity Based Authentication Schemes for Multi-Server Architecture

Since network services are provided cooperatively by multiple servers in the Internet,the authentication protocols for multiserver architecture are required by Internetbased services,such as online game,online trade and so on.Recently,Li et al.analyzed Lee et al.'s protocol and proposed an improved dynamic identity based authentication protocol for multi-server architecture.They claimed that their protocol provides user's anonymity,mutual authentication and the session key agreement against several kinds of attacks.In this paper,a cryptanalysis on Lee et al.'s scheme shows that Lee et al.'s protocol is also vulnerable to malicious server attack,stolen smart card attack and leak-of-verifier attack.Moreover,Li et al.'s improved protocol is also vulnerable to all these attacks.Further cryptanalysis reveals that Li et al.'s improved protocol is susceptible to collusion attack.

Analysis and Improvement on a Hash-Based Authentication Scheme for Multi-Server Architecture

In order to meet people’s demand for various types of network services,researchers have conducted extensive research on authentication schemes for multi-server architecture.Although various schemes have been proposed,most of them still have safety defects and fail to meet safety requirements.Recently,Haq et al presented an efficient Hash-based authenticated key agreement scheme for multi-server scheme and claimed that their scheme can withstand all well-known attacks.However,we find that their scheme is vulnerable to replay attack,tracking attack and malicious server impersonation user attack.Then we propose an improved scheme.We also analyze the security of the improved scheme and compare with Haq et al’s scheme in security and computational efficiency.Furthermore,we use the AVISPA(Automated Validation of Internet Security Protocols and Applications)tool to verify the security of the improved scheme.

建行信用卡系统全栈国产化改造研究

信用卡业务是业务逻辑最复杂的银行业务之一,其对可用性、可靠性、处理性能要求较高。从技术发展角度来看,多技术栈融合的新型IT架构,符合云计算资源池化的趋势。从业务角度来看,为满足不同的业务需求,同样存在多技术栈融合架构的诉求。然而,多计算架构并非简单实现一个全新的技术栈即可,需要解决架构改造与设计、系统验证、兼容性以及故障切换等一系列问题。面对上述挑战,该文面向金融IT系统高并发、高性能以及高可用需求,介绍了建行面向金融行业的高性能、高可用和高安全可靠的x86、ARM双平台混合架构系统中的设计与思考。通过一系列的代码迁移、应用迁移以及系统垂直优化技术,实现高性能、高可用和高安全的诉求,并在建行得到了大规模、长时间的真实系统验证。

面向动态边缘网络的数字孪生自适应联合优化部署

在数字孪生赋能的移动边缘计算(Mobile Edge Computing,MEC)网络中,如何实现数字孪生服务器的高效部署是确保数字孪生实时交互性的瓶颈问题。针对该问题,提出一种面向动态边缘网络的数字孪生自适应联合优化部署机制。首先,该机制构建面向动态边缘网络的双层数字孪生模型以实时捕捉MEC网络状态和UE资源利用情况等特征。然后,联合数字孪生交互时延模型、负载均衡模型和能源消耗模型建立数字孪生服务器自适应动态更新部署问题。最后,提出多阶段自适应动态联合部署优化算法,将数字孪生服务器自适应动态更新部署问题分解为数字孪生服务器初始化部署和自适应动态更新部署两阶段优化求解,以实现部署策略随MEC网络的即时系统状态进行自适应动态调整。仿真分析验证了所提出算法在预测精度、交互时延、工作负载和能耗方面的有效性。

身份加密多云多副本完整性审计协议

为解决现有可证明数据持有(PDP)协议只适用于单云存储服务器且过度依赖公钥基础设施的问题,提出一种新的基于身份的多云多副本PDP协议。该协议采用身份加密来简化证书管理,并设计双层默克尔哈希树作为新的安全数据结构,以维护多副本的新鲜性和一致性。安全性分析和实验结果均验证了该协议具备安全性和高效性,能够在多个云存储服务器上实现多副本完整性审计,并在标签生成、证据生成和证据验证3个阶段的效率上明显优于对比算法。

多服务器环境下基于椭圆曲线密码的认证协议

本文研究了多服务器环境下的认证密钥协商协议.通过对Andola等人方案的分析,利用椭圆曲线密码和随机数设计了一种改进的认证密钥协商协议.使用BAN逻辑和非形式化分析方法,对协议进行安全性分析.实验结果表明,所提协议具有更好的安全性和实用性.

面向利润优化的软实时云服务调度与多服务器系统配置方法研究

在云计算中,由于多核技术的不断革新,近年来有许多工作研究了基于多核处理器的多服务器系统。云服务提供商通过建立多服务器系统给用户提供云服务并优化云服务利润是目前云计算领域的一个热点问题,对这些问题的研究推动着云计算技术的不断发展。然而,现有的关于多服务器系统的研究要么局限于通过对多服务器计算资源的配置来优化云服务利润而忽视了云服务请求本身的可调度性,要么局限于开发服务请求调度策略来提升云服务利润而忽视了多服务器系统的动态扩展性。但若使用云服务请求调度与多服务器配置协同优化来提升云服务利润,则会使问题规模的复杂性呈指数增长。因此,为云服务提供商设计一个面向软实时云服务请求的云服务调度与多服务器配置方法是十分必要的。此外,现有的研究在配置多服务器系统时大多忽略了处理云服务请求会遭受瞬时故障的情况。而许多研究表明,软实时任务在遭受瞬时故障时会影响服务请求的执行结果从而影响云服务利润。本研究面向软实时云服务请求,针对云环境中普遍存在的计算性能异构的服务器资源,开发了一个基于深度搜索的灰狼算法来协同优化云服务请求调度和多服务器配置以最大化云服务利润。最后,为了验证所提方法的有效性,进行了大量实验,实证结果表明,与现有的基准方法相比,所提方法得到的云服务利润平均增加了6.83%。

基于深度强化学习的隐私保护任务卸载策略

针对多移动边缘计算(MEC)服务器网络中计算卸载任务特征隐私泄露的问题,提出了一种基于深度强化学习(DQL)的隐私保护的在线计算卸载新方法.该方法首先通过对计算卸载特征任务的隐私泄露进行度量,设定隐私泄露约束阈值,保护用户卸载的隐私信息;然后以最小化系统能耗为目标,将该优化问题转变为马尔可夫决策过程;最后利用深度Q网络(DQN)算法求解出满足隐私约束和最小化能耗目标的接近最优的卸载决策.实验结果表明,该算法能够在有效降低用户设备平均能耗的同时,使任务卸载频率始终满足隐私约束.

基于用户密度和平均访问时间的边缘服务器放置方法

为解决边缘服务器放置过程中资源浪费和延迟增加的问题,对边缘服务器放置方案的用户密度和平均访问时间进行分析建模,将其描述为多目标优化问题。设计了一种基于用户密度和平均访问时间的边缘服务器放置方案,并提出了一种多目标海马遗传算法(MOSGA)解决该问题。MOSGA首先使用多目标优化算法的思想对海马优化(sea horse optimizer,SHO)算法进行改进,使SHO算法能够适用于多目标优化问题,并在此基础上使用遗传算法改进SHO算法的繁殖操作,使MOSGA能更好地跳出局部最优解,加速问题的求解。该算法在上海电信数据集上进行了实验验证,仿真实验结果表明,MOSGA明显优于RA、K-means、NSGA、LMM,不仅有效解决了服务器资源浪费的问题,同时大大降低终端设备访问服务器的时间。

多线程多核服务器功耗模型及性能监控

针对现有服务器的CPU功耗准确性不足和多线程处理功耗负载不平衡问题,本文提出了一种多线程和多核服务器CPU功耗模型。该模型采用前后端分离的整体架构思想,根据服务器功耗模型实时获取CPU的线程数、频率及利用率。通过日志文件进行反馈多线程和多核功耗模型,达到最佳服务器负载平衡。仿真测试的结果表明,改进的服务器功耗模型在CPU利用率方面比传统服务器提高了6%,内存以及I/O通信方面也有明显改善,为多线程和多核服务器提供了一种新的功耗模型思路。

车联网边缘计算场景下基于改进型NSGA-Ⅱ算法的边缘服务器部署决策

车联网环境下,边缘服务器的放置位置与部署数量直接影响到边缘计算的效率。由于在宏基站或基站上部署大型边缘服务器的成本较高,可以在微基站上部署一个小型边缘服务器作为补充,并通过优化大型边缘服务器的放置位置来降低成本。为了最小化边缘服务器的部署代价和服务延迟、最大化运营商的收入和服务器负载均衡度,把边缘服务器放置问题与车联网用户应用服务放置问题联合建模为一个多目标优化问题,并提出了基于改进型NSGA-Ⅱ算法的放置方案。实验结果表明,提出的边缘服务器放置方案能够降低约44%的边缘服务器部署成本,降低约14.2%的时延,提升24.2%的运营商收入,具有较好的应用价值。

F级燃气机组DCS标准时间钟国产化研究

针对F级燃气机组分散控制系统(DCS)系统使用的某型号进口网络授时服务器的国产化研制进行了研究。该型号网络授时服务器的国产化研制,不是对原进口产品的功能和技术简单的仿制,而是结合了国家对于设备安全和生产方面的要求,将DCS网络授时服务器设计成一种可以满足各类应用场合,同时能够在不同应用等级的授时系统之间起到承上启下作用的统一的授时平台。

基于FTP协议的多源分布式下载技术研究与应用

传统FTP下载只有一个客户端和一个服务器,存在单点故障和性能瓶颈,且下载以交互式为主,对文件名不固定的文件不能自动下载。针对此问题,基于分布式调度技术提出多源分布式下载技术,实现多个下载客户端同时从多个FTP服务器下载相同的资料,提高FTP下载性能和可靠性;提出定时下载、延迟下载、文件名时间变量替换、按规则改名、二次分发等技术,实现任意文件的自动下载;使用bash开发了多源分布式下载软件,在测试环境和实际生产环境中的应用表明,多源分布式下载具有下载速度快、可靠性高的特点,每增加一个新的C/S下载链接,下载性能可以提升30%,增加一个客户端或一个服务器,可靠性提升一倍。

基于BiLSTM神经网络的多服务器门限服务系统性能分析

为了满足运行速度快、时延低、性能好、公平性好等特点,提出了多服务器门限服务系统,并利用BiLSTM(Bi-direc-tional Long Short-Term Memory)神经网络对其进行预测分析,使用多服务器接入方式来降低网络时延,改善系统性能。多个服务器调度时,可以采用同步和异步两种方式。首先,研究多服务器门限服务的系统模型。其次,在单服务器的基础上,利用嵌入马尔可夫链和概率母函数的分析方法对多服务器门限服务的平均排队队长、平均循环周期和平均时延进行求解;同时,利用Matlab进行仿真实验,分别将单服务器系统与多服务器系统的理论值与仿真值进行系统分析,对比多服务器同步和异步两种方式。最后,构建BiLSTM神经网络来预测多服务器系统的性能。实验结果表明,该多服务器系统异步方式优于同步和单服务器系统,多服务器异步系统的性能更好,时延更低,效率更高。综合对比多服务器的3种基本服务系统,在保证公平性的情况下,门限服务系统更加稳定。并且使用BiLSTM神经网络预测算法能够准确预测系统的性能,提高计算效率,对轮询系统的性能评价具有指导意义。

同步多重休假M/M/c不可视排队系统中的顾客行为及定价策略研究

本文研究同步多重休假M/M/c排队系统中顾客的止步行为和定价策略。当系统为空时,c个服务员同时进入休假状态,一次休假结束后,若系统仍为空,所有服务员继续进行下一次休假,否则同步返回工作状态。基于系统信息几乎不可视和完全不可视两种情形,首先推导出系统的队长稳态分布和顾客的平均逗留时间等性能指标,接着分别从个人最优和系统整体最优的角度出发建立个人剩余效用函数和单位时间社会收益函数,得到两种情形下顾客的均衡止步策略与社会最优止步策略,然后依此为系统制定定价策略,以实现社会收益的最大化。最后,通过数值实验,分别对两种情形下顾客的均衡到达率,社会最优到达率,最优社会收益与系统定价策略关于服务员数量进行灵敏度分析,观察其变化规律及相互关系,以及信息量对顾客行为的影响。