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1.
广义Gray码及其在数字图像置乱中的应用   总被引:44,自引:0,他引:44  
以图像信息安全问题为背景,讨论了广义Gray码及其在数字图像中的置乱作用,推广了丁玮等人(1999年)的相关结果。给出了图像置乱变换的周期,得到了周期性的一个充分必要条件。  相似文献
2.
上市公司投资回报率的影响因素   总被引:2,自引:0,他引:2  
影响证券投资者投资回报率的因素有很多,本文使用逐步回归方法从众多的因素中挑选出了对投资回报率有较大影响的因素,并建立了这些因素与投资回报率之间的数学模型。  相似文献
3.
一种混沌多相伪随机序列   总被引:2,自引:0,他引:2       下载免费PDF全文
提出了一种混沌多相伪随机序列生成方法,推导出通过Logistic映射产生独立同分布多相序列的充分条件,即根据混沌轨迹的概率密度分布把混沌吸引子划分为2n个区域,对混沌轨迹进行采样间隔为n的采样,对照轨道点所处位置与相应的序列元素之间的映射关系,可以得到独立、均匀分布的2n相伪随机序列。数值统计分析支持以上研究结果并表明该序列具有较高的复杂度。此外文中给出了该序列生成的快速算法和一般表达式。该序列可用于信息安全、扩频通信等众多领域。   相似文献
4.
基于VaR-Copula的信息安全评价模型研究   总被引:1,自引:0,他引:1  
近年来,我国信息安全面临的形势越来越严峻,而作为信息安全风险防范的最基础手段——风险评价理论和方法还没有得到有效发展和真正发挥作用.研究在深入分析信息安全风险理论基础上,采用VaR理论和Copula法,构建了一种信息安全评价模型,得到了从整体上来把握和衡量信息安全的VaR指标,解决了现有研究主要集中于构建指标体系及其基础上评价模型的弊端.最后,并采用实例验证了该模型的有效性.  相似文献
5.
Securitizing and tranching longevity exposures   总被引:1,自引:0,他引:1  
We consider the problem of optimally designing longevity risk transfers under asymmetric information. We focus on holders of longevity exposures that have superior knowledge of the underlying demographic risks, but are willing to take them off their balance sheets because of capital requirements. In equilibrium, they transfer longevity risk to uninformed agents at a cost, where the cost is represented by retention of part of the exposure and/or by a risk premium. We use a signalling model to quantify the effects of asymmetric information and emphasize how they compound with parameter uncertainty. We show how the cost of private information can be minimized by suitably tranching securitized cashflows, or, equivalently, by securitizing the exposure in exchange for an option on mortality rates. We also investigate the benefits of pooling several longevity exposures and the impact on tranching levels.  相似文献
6.
Recently, Chien et al. proposed RSA-based partially blind signature with low computation for mobile and smart-card applications. Hwang et al. claimed that Chien et al.’s scheme cannot meet the untraceability property of the blind signature later. In this paper, we show that Hwang et al.’s claim is incorrect and Chien et al.’s scheme is still satisfy the untraceability property.  相似文献
7.
We develop and simulate a basic mathematical model of the costly deployment of software patches in the presence of trade-offs between confidentiality and availability. The model incorporates representations of the key aspects of the system architecture, the managers’ preferences, and the stochastic nature of the threat environment. Using the model, we compute the optimal frequencies for regular and irregular patching, for both networks and clients, for two example types of organization, military and financial. Such examples are characterized by their constellations of parameters. Military organizations, being relatively less cost-sensitive, tend to apply network patches upon their arrival. The relatively high cost of applying irregular client patches leads both types of organization to avoid deployment upon arrival.  相似文献
8.
随着信息化的发展,信息安全得到前所未有的重视,国家主管机构的监管越来越严厉,企业在面临强制压力的合规性问题时可以选择自行部署,也可以选择服务外包.通过建立数学模型模拟了这个过程.分析结果表明:在强制压力情况下,如果用户选择外包方式,那么用户信息系统的期望值随着强制压力的提高而降低,信息安全服务供应商的利润则随着强制压力的提高而提高.  相似文献
9.
In this paper, we model a possible deception system with the explicit purpose of enticing unauthorized users and restricting their access to the real system. The proposed model represents a system designer’s defensive actions against intruders in a way that maximizes the difference between the intruders’ cost and the system designer’s cost of system protection. Under the assumption of a dual entity system, the proposed model shows that intruders differ in behavior depending on the system’s vulnerability at the time of intrusion as well as depending on their own economic incentives. The optimal results of the proposed model provide the system designer with insights on how to configure the level of protection for the two systems.  相似文献
10.
信息是电子商务至关重要的资产,电子商务的正常运转必须建立在安全的信息系统之上,因而电子商务信息系统安全问题成为人们日益关注的重点.根据电子商务信息系统特点,从信息系统过程(Process)、资源(Resource)和安全目标(Security)三个视角分析了电子商务信息安全风险的要素及其关系,构建了三维信息系统安全管理体系模型PRS-ISMS,提出了改进的信息安全风险管理过程PRS-PDCA.  相似文献
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