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不良短信的泛滥严重影响了社会风气,干扰了人们正常的生活秩序,研发不良短信过滤技术具有相当高的实用价值.研究了文本分类中的两个问题,可应用于不良短信过滤.其一是应用聚类方法进行不可靠语料集的提纯,实验表明,该方法对不可靠数据的提纯效果比较明显;其二是关于IDF词权度量指标的一点改进. 相似文献
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In logical circuits, like arithmetic operations in a processor system, arbitrary faults become a more tremendous aspect in future. Modern manufacturing processes lead to less reliability and higher vulnerability of software execution to soft-errors. The correctness of certain results is important especially for safety–critical applications whose reliability depends on the fault-free execution of each single instruction and the dependencies between them. The more complex a software is the more unreliable the outcome is. But, there is a contrary effect. If the probability for multiple faults increases, there is also the chance that two faults compensate each other and the result is correct again. This paper presents the basic ideas for such a reliability evaluation of a software's data flow with arbitrary soft-errors and the effect of fault compensation. Further, this evaluation provides a possibility to compare different implementations of a data flow with respect to the reliability. This is shown by the comparison of two different error codes as alternatives for coded data processing. 相似文献
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针对Ad Hoc网络易遭受黑洞攻击而造成大量丢包现象的安全问题,提出了一种基于非合作博弈理论的安全路由方法。以Ad Hoc网络节点和恶意节点为对象建立双人博弈模型,理论分析证明该模型存在纳什均衡点,即对博弈的双方均存在优势策略。Ad Hoc网络根据自己的优势策略选择路由进行防御和网络传输,恶意节点根据自己的优势策略采取网络攻击行为。分析和仿真结果表明,新方法能有效地选择比较安全的路由,从而减少了恶意节点对Ad Hoc网络进行黑洞攻击造成的影响,降低了路由开销和网络丢包率。 相似文献
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JFK协议的分析与改进 总被引:2,自引:0,他引:2
JFK(just fast keying)协议是一种新型的Internet密钥交换协议,具有高效、安全和较好的防DoS(denial of services)攻击的特点。但是JFK协议也有自身的缺陷,比如没有实现PFS(perfect forward secrecy)。对JFK协议进行了详细的分析,通过增加循环DH队列、改变消息的内容和改进消息处理方式的方法对JFK协议进行了改进,改进后的JFK协议在不牺牲效率的情况下实现了PFS,并且具有更好的防DoS攻击和重放攻击的能力。 相似文献
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Dynamic time-linkage optimization problems (DTPs) are a special class of dynamic optimization problems (DOPs) with the feature of time-linkage. Time-linkage means that the decisions taken now could influence the problem states in future. Although DTPs are common in practice, attention from the field of evolutionary optimization is little. To date, the prediction method is the major approach to solve DTPs in the field of evolutionary optimization. However, in existing studies, the method of how to deal with the situation where the prediction is unreliable has not been studied yet for the complete Black-Box Optimization (BBO) case. In this paper, the prediction approach EA + predictor, proposed by Bosman, is improved to handle such situation. A stochastic-ranking selection scheme based on the prediction accuracy is designed to improve EA + predictor under unreliable prediction, where the prediction accuracy is based on the rank of the individuals but not the fitness. Experimental results show that, compared with the original prediction approach, the performance of the improved algorithm is competitive. 相似文献
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根据移动自组网(MANET)中常见的路由协议安全威胁,结合卫星网络的特性,分析辅助定位按需路由(LAOR)协议可能存在的安全问题,得出LAOR协议安全改进的要点,通过引入基于身份的密码体制以实现节点间路由控制分组的相互认证,并利用节点私钥对路由控制分组签名以保护路由控制分组的完整性。利用串空间对改进后的路由协议进行分析,并证明它满足plausible routing,是安全的。 相似文献
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为更好发挥DAA协议在隐私保护方面的作用,提高协议自身的安全性,对现有DAA协议的性能及安全进行了分析,列举了协议在提高性能方面所采取的优化策略及其满足的安全属性.重点分析了协议可能存在的安全问题,如RSA安全问题、恶意Issuer问题、Rudolph攻击、跨域认证问题等,特别指出现有协议存在的共性安全问题:只满足RO模型下可证明安全性.提出解决上述问题的具体方法及所需技术,为构建新的DAA方案、实现新方案在标准模型下的安全性证明奠定理论基础. 相似文献
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《Computer Networks and ISDN Systems #》1986,11(2):121-131
The Fiber Distributed Data Interface (FDDI) is an ANSI draft proposed standard for a 100 megabit per second token ring using fiber optics as the transmission medium. The FDDI design represents an extensive effort to incorporate reliability mechanisms as an integral part of the design. These mechanisms provide fault detection and isolation functions, monitoring functions, and configuration functions. The purpose of this paper is to discuss these reliability mechanisms, and to compare and contrast them with reliability mechanisms which have been incorporated in other local area network architectures. 相似文献
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摘 要:针对PEGASIS协议中通信时延长、节点与节点之间存在长链、网络维护代价大的缺点,该论文在分析和仿真PEGASIS协议的基础上提出一种改进协议PEGASIS-I(PEGASIS-Improved)。该协议将监测区域看成是以基站为中心的圆形区域,基站生成参数 并将圆形区域分成2π/ 个子区域,子区域内节点与节点形成路由树,数据先从树叶传输至树根,再由树根发送至基站。Matlab仿真表明:与PEGASIS协议相比PEGASIS-I协议有效降低了数据传输延迟58%、避免了长链、延长了网络生存时间198%。 相似文献
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会话初始化协议(SIP)提供了认证和协商会话密钥,能保证后续会话的安全。2010年,Yoon等(YOON E-J,YOO K-Y.A three-factor authenticated key agreement scheme for SIP on elliptic curves.NSS'10:4th International Conference on Network and System Security.Piscataway:IEEE,2010:334-339)提出一种新的三要素SIP认证密钥协商协议TAKASIP。但TAKASIP协议不能抵抗内部攻击、服务器伪装攻击、离线口令猜测攻击、身份冒充攻击和丢失标记攻击,并且没有提供双向认证。在TAKASIP协议基础上提出一种基于椭圆曲线密码三要素SIP认证协议ETAKASIP以解决上述问题。ETAKASIP基于椭圆曲线离散对数难题和椭圆曲线密码系统,提供了高安全性。该协议只需7次椭圆曲线点乘运算、1次椭圆曲线加法运算和最高6次哈希运算,有较高的运算效率。 相似文献
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提出无线传感器网络路由算法IDEEC (Improvement Distribute Energy-Efficient Clustering Algorithm for Heterogeneous Wireless Sensor Networks),该算法具有能量消耗低的优点,基于传输时延的考虑,采用多跳方式传送数据.通过与Leach和DEEC的路由的协议的仿真结果比较,本路由算法的网络生存周期分别提高了50%和30%. 相似文献
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简要分析了基于树结构与门限思想的组密钥协商协议的工作步骤及群组成员变动的时的密钥更新过程,经过分析发现TTS协议在密钥更新阶段存在攻击者重放或篡改发起者所广播消息的安全漏洞.描述了这种攻击的过程,对协议的改进提出改进思路,发起者对其广播的消息进行了签名,服务器能够验证发起者的身份信息及消息的新鲜性,描述了具体的改进方法.分析结果表明,改进地方法保留了TTS协议的良好性质,以较小的代价弥补了原协议的缺陷. 相似文献
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Bozena Kwiat uszewska- Sarnecka 《国际自动化与计算杂志》2006,3(2):157-164
In the paper, excess methods for improving the reliability of multi-state series-parallel systems are presented: for the hot reserve of single components, the cold reserve of single components, and the mixed (hot and cold) reserve of single components. A process is also introduced to improve the reliability of these methods by replacing their components with more reliable ones. New theorems for multi-state limit reliability functions in homogeneous and non-homogeneous series-parallel large systems composed of components with improved reliability are presented, and applied to compare the effects of these systems in different reliability improving methods. 相似文献
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分析了地理路由协议GPSR的特性,并针对GPSR协议在遇到空洞时,贪婪算法失效而出现的消耗过多能量的情况,提出了一种简易的能量改进策略,以减少由于GPSR协议中周围模式引起的过多的跳跃。基于这种策略,提出了一种改进的地理路由协议。在路由子集节点被动获得的局部网络信息的帮助下,此协议能裁减路由线路,以减少由GPSR的周围模式引起的很大一部分跳跃。 相似文献