836 resultados para model-based security management


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网络脆弱性分析是近年来国内外研究的热点问题之一.基于攻击能力增长的网络安全性分析模型以攻击者的能力增长为主导,参考网络环境配置,模拟黑客攻击自动生成攻击图.使用攻击能力增长表示攻击者的最终目标使得攻击图的表示更为准确.最小攻击代价分析第1次考虑了相似攻击对攻击代价的影响,以便对各条路径的攻击代价进行计算;最小环境改变分析考虑入侵检测的因素对最可能的攻击路径进行分析,对于入侵检测系统的处理更加科学合理;两种分析都为改善网络配置提供了依据.与已有成果相比,模型提出的算法和方法更为实际可行.

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安全态势评估是近年来国内外在网络安全领域的研究热点之一.对已有的安全态势评估方法进行了详细分析和比较,针对网络安全中多数据源的特点,提出基于信息融合的网络安全态势评估模型,引入改进的D-S证据理论将多数据源信息进行融合,利用漏洞信息和服务信息,经过态势要素融合和节点态势融合计算网络安全态势,绘制安全态势曲线图,同时对态势计算结果进行时间序列分析,从而实现网络安全趋势的预测.最后利用网络实例数据,对所提出的网络安全态势评估模型和算法进行了验证,结果表明该模型比已有成果更加有效和准确.

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实施第三方安全功能独立测试是信息安全产品测评中的一个重要环节,对于以安全数据库管理系统为代表的信息安全产品,其系统规约的测试并不能完全真实反映系统行为,还需要满足系统安全策略.提出了基于安全策略模型的安全功能测试用例自动生成方法,该方法包括基于语法的划分、基于规则的划分、基于类型的划分等步骤,依据形式化安全模型生成正确描述系统行为的操作测试用例集.该方法有助于提高测试质量,发现手工测试中难以发现的缺陷,并有助于减少测试过程中的重复劳动,实现测试自动化并提高测试效率.

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为解决LSM在策略重用和策略共存方面存在的问题,提出了一个新的安全体系结构ELSM,它引入一个模型组合器作为主模块实施模块堆栈管理和模块决策管理,其中模块决策的实施采用了访问控制空间的策略规范方法,可支持通用性,ELSM的设计及其在安胜OS安全操作系统中的实例分析表明其有效性。

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文章分析和比较了目前的安全态势评估方法,提出了一种基于日志审计与性能修正算法的网络安全态势评估模型.首先利用日志审计评估节点理论安全威胁,并通过性能修正算法计算节点安全态势.然后利用节点服务信息计算网络安全态势,并且采用多种预测模型对网络安全态势进行预测,绘制安全态势曲线图.最后构建了一个网络实例,使用网络仿真软件对文中提出的态势评估模型和算法进行了验证.实验证明该方法切实有效,比传统方浇法更准确地反映了网络的安全态势和发展趋势.

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安全策略的形式化分析与验证随着安全操作系统研究的不断深入已成为当前的研究热点之一.文中在总结前人工作的基础上,首次提出一种基于UML和模型检测器的安全模型验证方法.该方法采用UML将安全策略模型描述为状态机图和类图,然后利用转换工具将UML图转化为模型检测器的输入语言,最后由模型检测器来验证安全模型对于安全需求的满足性.作者使用该方法验证了DBLP和SLCF模型对机密性原则的违反.

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To investigate the seasonal and interannual variations in biological productivity in the South China Sea (SCS), a Pacific basin-wide physical - biogeochemical model has been developed and used to estimate the biological productivity and export flux in the SCS. The Pacific circulation model, based on the Regional Ocean Model Systems (ROMS), is forced with daily air-sea fluxes derived from the NCEP (National Centers for Environmental Prediction) reanalysis between 1990 and 2004. The biogeochemical processes are simulated with a carbon, Si(OH)(4), and nitrogen ecosystem (CoSiNE) model consisting of silicate, nitrate, ammonium, two phytoplankton groups (small phytoplankton and large phytoplankton), two zooplankton grazers (small micrograzers and large mesozooplankton), and two detritus pools. The ROMS-CoSiNE model favourably reproduces many of the observed features, such as ChI a, nutrients, and primary production (PP) in the SCS. The modelled depth-integrated PP over the euphotic zone (0-125 m) varies seasonally, with the highest value of 386 mg C m (-2) d (-1) during winter and the lowest value of 156 mg C m (-2) d (-1) during early summer. The annual mean value is 196 mg C m (-2) d (-1). The model-integrated annual mean new production (uptake of nitrate), in carbon units, is 64.4 mg C m (-2) d (-1) which yields an f-ratio of 0.33 for the entire SCS. The modelled export ratio (e-ratio: the ratio of export to PP) is 0.24 for the basin-wide SCS. The year-to-year variation of biological productivity in the SCS is weaker than the seasonal variation. The large phytoplankton group tends to dominate over the smaller phytoplankton group, and likely plays an important role in determining the interannual variability of primary and new production.

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从提升产品市场竞争力的角度,提出了面向产品竞争力设计和经营决策的理念,建立了有关的结构模型和框架模型。在此基础上,进一步提出了并行工程环境下实现基于产品开发周期的面向产品竞争力设计与经营决策一体化的设想;研究了面向产品竞争力设计与经营决策集成系统的特征、结构和功能。最后以汽车车身为例对并行工程环境下的车身设计与经营决策集成系统进行了应用研究。

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本文分析了工作流管理系统的现状及存在的问题 ,提出了基于 agent的工作流协调管理模型 .该模型在面向对象的工作流元过程模型基础上 ,利用 agent和面向对象技术 ,建立协调 agent、实例化 agent和活动 agent模型 ,提高系统的自组织、自学习和协调能力 .

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柔性是柔性制造系统(FMS)的一个基本优点,但这一基本优点却往往被人们所忽视,许多现在运行的FMS不是缺乏柔性,就是没能充分利用可获得的柔性来提高生产效率柔性制造系统的负荷分配和路径规划问题正是这种柔性的一个主要方面.然而,路径规划决策却往往被忽视.其中一个主要原因就是人们仍不能从传统的生产管理概念中解放出来.本文在明确概念区分的基础上,提出了一种柔性制造系统的负荷分配和路径规划的线性规划模型,其主要特点是将负荷分配和路径规划问题有机地结合起来,并通过仿真实验验证并分析了此方法对FMS性能上的影响。

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为提高制造系统生产控制的性能,建立了基于多智能体系统的混合控制模型。该模型把生产控制系统分为管理智能体层、单元智能体层和执行智能体层。管理智能体层负责调度和协调各单元智能体,并对所有智能体进行管理;单元智能体层中的各单元智能体间通过公用数据库相互协作;执行智能体对制造系统内的硬件负责,它们根据局部的本地资源信息及当前状态,接收发布的任务,并对其求解。同一层次的智能体之间是分布式结构。采用基于多智能体的混合控制模式,提高了制造系统生产控制的实时性和灵活性。通过激光拼焊生产系统中的试验,验证了该模型的有效性。

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As a typical geological and environmental hazard, landslide has been causing more and more property and life losses. However, to predict its accurate occurring time is very difficult or even impossible due to landslide's complex nature. It has been realized that it is not a good solution to spend a lot of money to treat with and prevent landslide. The research trend is to study landslide's spatial distribution and predict its potential hazard zone under certain region and certain conditions. GIS(Geographical Information System) is a power tools for data management, spatial analysis based on reasonable spatial models and visualization. It is new and potential study field to do landslide hazard analysis and prediction based on GIS. This paper systematically studies the theory and methods for GIS based landslide hazard analysis. On the basis of project "Mountainous hazard study-landslide and debris flows" supported by Chinese Academy of Sciences and the former study foundation, this paper carries out model research, application, verification and model result analysis. The occurrence of landslide has its triggering factors. Landslide has its special landform and topographical feature which can be identify from field work and remote sensing image (aerial photo). Historical record of landslide is the key to predict the future behaviors of landslide. These are bases for landslide spatial data base construction. Based on the plenty of literatures reviews, the concept framework of model integration and unit combinations is formed. Two types of model, CF multiple regression model and landslide stability and hydrological distribution coupled model are bought forward. CF multiple regression model comes form statistics and possibility theory based on data. Data itself contains the uncertainty and random nature of landslide hazard, so it can be seen as a good method to study and understand landslide's complex feature and mechanics. CF multiple regression model integrates CF (landslide Certainty Factor) and multiple regression prediction model. CF can easily treat with the problems of data quantifying and combination of heteroecious data types. The combination of CF can assist to determine key landslide triggering factors which are then inputted into multiple regression model. CF regression model can provide better prediction results than traditional model. The process of landslide can be described and modeled by suitable physical and mechanical model. Landslide stability and hydrological distribution coupled model is such a physical deterministic model that can be easily used for landslide hazard analysis and prediction. It couples the general limit equilibrium method and hydrological distribution model based on DEM, and can be used as a effective approach to predict the occurrence of landslide under different precipitation conditions as well as landslide mechanics research. It can not only explain pre-existed landslides, but also predict the potential hazard region with environmental conditions changes. Finally, this paper carries out landslide hazard analysis and prediction in Yunnan Xiaojiang watershed, including landslide hazard sensitivity analysis and regression prediction model based on selected key factors, determining the relationship between landslide occurrence possibility and triggering factors. The result of landslide hazard analysis and prediction by coupled model is discussed in details. On the basis of model verification and validation, the modeling results are showing high accuracy and good applying potential in landslide research.

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This paper consists of two major parts. First, we present the outline of a simple approach to very-low bandwidth video-conferencing system relying on an example-based hierarchical image compression scheme. In particular, we discuss the use of example images as a model, the number of required examples, faces as a class of semi-rigid objects, a hierarchical model based on decomposition into different time-scales, and the decomposition of face images into patches of interest. In the second part, we present several algorithms for image processing and animation as well as experimental evaluations. Among the original contributions of this paper is an automatic algorithm for pose estimation and normalization. We also review and compare different algorithms for finding the nearest neighbors in a database for a new input as well as a generalized algorithm for blending patches of interest in order to synthesize new images. Finally, we outline the possible integration of several algorithms to illustrate a simple model-based video-conference system.

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There has been much interest in the area of model-based reasoning within the Artificial Intelligence community, particularly in its application to diagnosis and troubleshooting. The core issue in this thesis, simply put, is, model-based reasoning is fine, but whence the model? Where do the models come from? How do we know we have the right models? What does the right model mean anyway? Our work has three major components. The first component deals with how we determine whether a piece of information is relevant to solving a problem. We have three ways of determining relevance: derivational, situational and an order-of-magnitude reasoning process. The second component deals with the defining and building of models for solving problems. We identify these models, determine what we need to know about them, and importantly, determine when they are appropriate. Currently, the system has a collection of four basic models and two hybrid models. This collection of models has been successfully tested on a set of fifteen simple kinematics problems. The third major component of our work deals with how the models are selected.

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Joern Fischer, David B. Lindermayer, and Ioan Fazey (2004). Appreciating Ecological Complexity: Habitat Contours as a Conceptual Landscape Model. Conservation Biology, 18 (5)pp.1245-1253 RAE2008