Data Mining - Concepts and Techniques.

Most of the current research in security analysis has been centered on identifying threats and vulnerabilities and providing suitable defense mechanisms to improve the robustness of the network and systems. While this approach is attractive, it provides limited insight into understanding the impact these attacks have on the overall security goals of the network and the system. Attack Graph as a model lends itself nicely to the analysis of the security state of a network. Most of the Attack graph based metrics proposed in the literature are one dimensional; however the research community has acknowledged the fact that security needs to be treated as a multidimensional concept. In this paper, we utilize stochastic modeling techniques using Attack graphs to define a complementary suite of quantitative metrics to aid the security engineer in visualizing the current as well as future security state of the network and optimizing the necessary steps to harden the enterprise network from external threats. We present experimental results from applying this model on a sample network to demonstrate the practicality of our approach.

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Cyber Security Analytics: A Stochastic Model for Security Quantification Using Absorbing Markov Chains

In order to exploring the inherent rule of information security risk assessment development, based on information system or asset structure and operation status, a survey is proposed in which the common risk assessment methods are divided into four types: vulnerability identification and risk assessment, risk factors simulation and risk estimation, security situation assessment, the risk calculation based on business process analysis. The method on delving into the information system of the highest level structure--namely business process structure and change is advocated, on which business operating performance indicators are regarded as risk scale, so real-time and dynamically information security risk calculation is obtained. Finally, Based on an understanding of the information system structure and utilization, combined with feedback control theory, three levels of judgment is defined which positions information security risk assessment method status, and the information security risk assessment study on the return to the rule of non-linear system.

Survey of Information Security Risk Assessment

Security metrics serve as a powerful tool for organizations to understand the effectiveness of protecting computer networks. However majority of these measurement techniques don’t adequately help corporations to make informed risk management decisions. In this paper we present a stochastic security framework for obtaining quantitative measures of security by taking into account the dynamic attributes associated with vulnerabilities that can change over time. Our model is novel as existing research in attack graph analysis do not consider the temporal aspects associated with the vulnerabilities, such as the availability of exploits and patches which can affect the overall network security based on how the vulnerabilities are interconnected and leveraged to compromise the system. In order to have a more realistic representation of how the security state of the network would vary over time, a nonhomogeneous model is developed which incorporates a time dependent covariate, namely the vulnerability age. The daily transition-probability matrices are estimated using Frei's Vulnerability Lifecycle model. We also leverage the trusted CVSS metric domain to analyze how the total exploitability and impact measures evolve over a time period for a given network.

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A Predictive Framework for Cyber Security Analytics using Attack Graphs

Near UV-pumped yellow-emitting Ca3TeO6:Dy3+ phosphor for white light-emitting diodes.

Evaluating security threat status is very important in network security management and analysis. A quantitative hierarchical threat evaluation model is developed in this paper to evaluate security threat status of a computer network system and the computational method is developed based on the structure of the network and the importance of services and hosts. The evaluation policy from bottom to top and from local to global is adopted in this model. The threat indexes of services, hosts and local networks are calculated by weighting the importance of services and hosts based on attack frequency, severity and network bandwidth consumption, and the security threat status is then evaluated. The experiment results show that this model can provide the intuitive security threat status in three hierarchies: services, hosts and local networks so that system administrators are freed from tedious analysis tasks based on the alarm datasets to have overall security status of the entire system. It is also possible for them to find the security behaviors of the system, to adjust the security strategies and to enhance the performance on system security. This model is valuable for guiding the security engineering practice and developing the tool of security risk evaluation.

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Quantitative Hierarchical Threat Evaluation Model for Network Security

Luminescent Characters and Energy Transfer Mechanisms of BaGd2(MoO4)4∶Tb3+,Eu3+ Phosphors

The current CSCL applications are not able to support learning task generation and personalized learning. To solve these issues, a method of task generation for personalized collaborative learning is proposed in this paper. Based on the formal description of learning task, the method could generate the collaborative learning task through five steps: grouping learners, determining learning resources, decomposing learning units, assigning learning pattern and generating event sequence. The task generated by the method accords with the cognitive level of learning group as well as the personality characteristics of the individual learner. According to the task, the personalized collaborative learning could be realized for the leaning group in the distributed environment. The method has been applied in Smart-Realcalss distance learning system.

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A Method of Task Generation for Personalized Collaborative Learning

A topological reconfiguration method for enhancing networks survivability with limited resources

利用高温固相法制备了一种新型红色荧光粉（Gd1-xEux）6（Te1-yMoy）O12，研究了Eu3+单掺和Eu3+，Mo6+共掺Gd6TeO12荧光粉的结构、形貌和荧光性能.实验结果表明，所合成的粉体为纯相.在393 nm近紫外光激发下，（Gd1-xEux）6（Te1-yMoy）O12荧光粉发出特征红光，位于632 nm处的发射主峰属于Eu3+的5D07F2跃迁.当Eu3+掺杂浓度超过20%（物质的量分数)时发光出现浓度淬灭，经证实这是由电偶极-电偶极相互作用造成的.随着工作温度升高，荧光粉发光强度减小，计算得到Eu3+热淬灭过程中的激活能为0.1796 eV.当（Gd0.8Eu0.2)6TeO12中共掺Mo6+（取代Te6+)，该荧光粉发射光谱的峰位、强度变化不大，但是Mo3+-O2-电荷迁移态显著增大了近紫外波段的激发带宽度,可以有效提高激发效率.具有近紫外宽带激发特征的(Gd0.8Eu0.2)6(Te0.6Mo0.4) O12是一种潜在的白光LED用荧光粉材料.

Zheng Qing-Hua

Papers

Quantitative Hierarchical Threat Evaluation Model for Network Security

Luminescent Characters and Energy Transfer Mechanisms of BaGd2(MoO4)4∶Tb3+,Eu3+ Phosphors

A Method of Task Generation for Personalized Collaborative Learning

A topological reconfiguration method for enhancing networks survivability with limited resources

Preparation and photoluminescent properties of near-UV broadband-excited red phosphor (Gd1-xEux)6(Te1-yMoy)O12 for white-LEDs