基于贝叶斯攻击图的网络安全量化评估研究

针对攻击图在评估网络安全时节点关系复杂、存在含圈攻击路径、只能反映网络静态风险等问题, 将攻击图与贝叶斯理论结合, 提出贝叶斯攻击图的概念, 简化了攻击图并通过优化算法避免了含圈路径的产生; 通过引入攻击证据与CVSS评分系统, 提出了一种新的面向脆弱点的网络安全量化评估方法, 基于贝叶斯攻击图对网络整体及局部的安全状况进行实时动态评估。通过在实际网络中的实验验证了该方法的可行性及有效性, 与传统评估方法相比, 该方法能够动态地反映网络安全的态势变化情况。     

Mapreduce模型及支撑系统概述

MapReduce是由并行编程模型及相关支撑系统组成的数据处理框架,通过定义接口和运行时支持库,通过定义良好的接口和运行时支持库,能够自动并行执行大规模计算任务,通过隐藏底层实现细节,降低实现并行编程的难度,Hadoop是目前MapReduce框架最流行的开源实现.文章首先介绍了MapReduce并行编程模型及其hadoop的运行原理、运行机制,深入研究了MapReduce计算任务在Hadoop系统中的运行过程.     

Set-membership methodology for model-based prognosis

This paper addresses model-based prognosis to predict Remaining Useful Life (RUL) of a class of dynamical systems. The methodology is based on singular perturbed techniques to take into account the slow behavior of degradations. The full-order system is firstly decoupled into slow and fast subsystems. An interval observer is designed for both subsystems under the assumption that the measurement noise and the disturbances are bounded. Then, the degradation is modeled as a polynomial whose parameters are estimated using ellipsoid algorithms. Finally, the RUL is predicted based on an interval evaluation of the degradation model over a time horizon. A numerical example illustrates the proposed technique.     

Stabilization of systems with interval time-varying delay based on delay decomposing approach

The paper considers the stabilization for systems with interval time-varying delay. By decomposing the delay interval into multiple equidistant subintervals and considering the triple integral terms, a novel Lyapunov-krasovskii functional(LKF) is defined. Then extended integral inequality and convex combination approach are used to estimate the derivative of the constructed functional, and as a result, the new stability criterion with less conservatism and decision variables is obtained. On this basis, the state feedback controller is designed, by using linearization method, the existence condition of controller is obtained in terms of linear matrix inequalities(LMIs), and the specific form of controller is also given, moreover, by selecting the appropriate parameter value, the stabilization time of the system can be reduced. Numerical examples are given to illustrate the effectiveness of the proposed method.     

Bucket Elimination: a Unifying Framework for Processing Hard and Soft Constraints

This position paper argues that extending the CSP model to a richer set of tasks such as, constraint optimization, probabilistic inference and decision theoretic tasks can be done within a unifying framework called bucket elimination. The framework allows uniform hybrids for combining elimination and conditioning guided by the problem's structure and for explicating the tradeoffs between space and time and between time and accuracy.     

有关非标定图色多项式的组合含义

本文根据Ｐ．Ｈａｎｌｏｎ给出的计算非标定图色多项式的表达式,地标定图的自同构群中各种转换情况的讨论,给出非标定图色多项式的前四项色系数的组合表达式,并归纳了表达式中各参数计算的一般步骤。本文还给出坟解非标定图色多项式的实例,以验证理论推导所得的结论。     

特殊图的图修正问题研究综述

图修正问题是指在一个图中进行删除点、删除边或加边操作,使这个图转变成另一个具有某种特殊性质的图。图修正问题一直被广泛研究,尤其对弦图、区间图以及单位区间图的图修正问题的研究更是如此。弦图是完美图中最重要的一类图,也是(单位)区间图的父类图,很多经典的NP难问题在弦图上都是多项式可解的。区间图以及单位区间图在生物计算上有着广泛的应用。对这几类图的图修正问题的研究对计算机理论和实践有很大的贡献。首先介绍并总结了关于弦图、区间图以及单位区间图的图修正问题的重要算法和技术,然后对这些问题的研究现状进行分析,并提出了今后研究中值得关注的问题。     

Attitude‐synchronization flocking of multiple 3‐dimensional nonholonomic agents without position measurement

This paper studies the attitude‐synchronization flocking problem for multiple 3‐dimensional nonholonomic agents. By analyzing the nonlinearity of the nonholonomic model and invoking the neighbor‐based design principle, we develop a distributed linear control protocol with the local information from each agent and its neighbors in proximity, especially, no position measurement is employed. Based on max‐min and Lyapunov stability theory, the proposed distributed control protocol can ensure the 3 flocking rules and attitude synchronization meanwhile, if collision avoidance and communication connectivity are guaranteed at the initial time. Additionally, numerical simulations are provided to verify the theoretical results.     

Balanced containment control and cooperative timing of a multiagent system over random communication graphs

A multiagent system is considered, which is tasked with the objective of approaching a predetermined target from a desired region to minimize detection and then simultaneously converge at the target. The considered cooperative timing problem consists of 2 stages: navigation and simultaneous arrival. During the navigation stage, the agents are driven from a distant starting point toward the target while restricting their motion within a desired area. Only a few agents (ie, leaders) are equipped with the desired bearing information to the target, whereas the remaining agents (ie, followers) may only have local feedback with neighboring agents to coordinate their headings. No range information to the target and no absolute or other relative position information among agents are available. The arrival stage begins when agents enter a neighborhood of the target (ie, range information becomes available during the arrival stage), and agents coordinate their motion to perform simultaneous arrival. The agents could experience random loss of communication with immediate neighbors, which results in a stochastic communication network. On the basis of the random communication network, balanced containment control is developed, which almost surely restricts the motion of the group within a desired region while equally spacing the agents. An almost sure consensus algorithm is designed for agents to coordinate the simultaneous arrival time by achieving a consensus on informed agents during the arrival stage. Simulation results demonstrate the performance of the developed approach.     

Fast processing of graph queries on a large database of small and medium-sized data graphs

We propose a new way of indexing a large database of small and medium-sized graphs and processing exact subgraph matching (or subgraph isomorphism) and approximate (full) graph matching queries. Rather than decomposing a graph into smaller units (e.g., paths, trees, graphs) for indexing purposes, we represent each graph in the database by its graph signature, which is essentially a multiset. We construct a disk-based index on all the signatures via bulk loading. During query processing, a query graph is also mapped into its signature, and this signature is searched using the index by performing multiset operations. To improve the precision of exact subgraph matching, we develop a new scheme using the concept of line graphs. Through extensive evaluation on real and synthetic graph datasets, we demonstrate that our approach provides a scalable and efficient disk-based solution for a large database of small and medium-sized graphs.