数据挖掘中的关联规则在入侵检测系统中的应用

由于知识发现的快速发展,对海量数据分析和处理的技术、能力也日渐成熟。从1999年起,就开始了将数据挖掘技术和入侵检测系统结合的尝试。将数据挖掘引入入侵检测系统的原因是它能够从大量的数据中自动提取出特征和模型,自动维护模式或特征库。系统利用这些大量的特征和数据进行有效的分类,加快处理速度,提高准确度。文章针对网络安全当中的大量的入侵事件,结合数据挖掘中的关联规则的概念,建立特征库及其特征关联,通过审计处理来加强网络入侵检测系统的功能。     

航空维修差错的研究

从航空维修差错带来的重大危害出发,提出航空维修差错的定义及基本特征;从人与硬件、人与软件、人与环境之间的关系入手,深入分析航空维修差错的几种模式,重点研究了最活跃、最突出的人为差错模式,并通过实际应用指出预防各种差错模式的方法和措施,有利于加强航空维修工作,提高维修工作的效率和质量,保证飞行的安全性.     

航空电子系统通用测试平台的设计

本文采用新一代测控技术,构建了基于PXI总线标准,由信号适配器、矩阵开关、可视化虚拟数据采集系统和通用总线监控系统组成的标准化通用测试平台。同时介绍了ARINC429总线数据按照规则进行解析的方法。其技术思想和方案对于复杂电子设备的通用测试设备的研制具有广泛指导意义。     

浅谈外军飞机战损评估与修理

飞机战损修理是现代战争战斗力的"倍增器".本文通过分析外军飞机战损评估与修理的发展历程和战损修理理念,介绍了外军战损飞机评估和修理的基本步骤和使用的主要工具,并结合理论研究、战损修理训练以及在系统全寿命过程中考虑战损修理的几个方面,论述了对我军战损修理的启示.     

航天国防科技报告的编写与检索利用

阐述了航天国防科技报告的基本概念和撰写航天国防科技报告的意义,介绍了航天国防科技报告的编写规则与撰写中常遇到的问题,最后论述了航天国防科技报告交流使用的意义。     

Haynes 282新型高温合金晶粒长大行为及数学模型研究

为了研究新型合金在高温状态下的晶粒长大行为,进行了Haynes 282合金在973～1 373 K条件下保温0～10 800 s的晶粒长大实验,通过实验分析了保温时间和保温温度对其晶粒尺寸的影响,研究了晶粒尺寸在其实验条件下的演变规律。由此构建了符合Haynes 282合金晶粒长大的数学模型,该模型的建立能够有效表征Haynes 282合金在高温下的晶粒长大行为。     

基于分散式RHC算法的无人机编队碰撞避免研究

提出了一种基于滚动时域控制(Receding Horizon control)的,保证无人机编队在飞行过程中满足约束条件并且防撞的分散式控制设计方案.此方法中,每架UAV都可以做出紧急自由碰撞规避机动,以保证冲突避免和约束履行.使用不变集合方法和强制协同的逻辑规则保证了在飞行中UAV之间的碰撞避免.仿真证明,此种分散式RHC方法是有效的.     

Reduction rules-based search algorithm for opportunistic replacement strategy of multiple life-limited parts

The opportunistic replacement of multiple Life-Limited Parts(LLPs) is a problem widely existing in industry.The replacement strategy of LLPs has a great impact on the total maintenance cost to a lot of equipment.This article focuses on finding a quick and effective algorithm for this problem.To improve the algorithm efficiency, six reduction rules are suggested from the perspectives of solution feasibility, determination of the replacement of LLPs, determination of the maintenance occasion and solution optimality.Based on these six reduction rules, a search algorithm is proposed.This search algorithm can identify one or several optimal solutions.A numerical experiment shows that these six reduction rules are effective, and the time consumed by the algorithm is less than 38 s if the total life of equipment is shorter than 55000 and the number of LLPs is less than11.A specific case shows that the algorithm can obtain optimal solutions which are much better than the result of the traditional method in 10 s, and it can provide support for determining tobe-replaced LLPs when determining the maintenance workscope of an aircraft engine.Therefore,the algorithm is applicable to engineering applications concerning opportunistic replacement of multiple LLPs in aircraft engines.     

美国政府促进基础研究的措施

为了借鉴美国加强基础研究工作的经验,促进我国基础研究的发展,研究了近年来美国国会、国防部及一些研究机构关于基础研究的咨询报告和评估报告。总结了美国加强基础研究的主要措施,包括:加大政府投入力度、减少行政部门干预、加强与大学合作、建设政府科研机构、发挥项目经理作用和制定明确的科技战略等。并针对我国基础研究工作的不足,提出了加强基础研究的投入力度、稳定从事基础研究的科技队伍、改进基础研究的项目管理等建议。     

Space debris mitigation measures applied to European launchers

In November 1986, more than 20 years ago, an H8 upper stage of Ariane 1 exploded in orbit nine months after the end of its mission. So as to avoid the generation of debris in low Earth orbit, a dedicated complementary development modified the design, introducing systematic passivation of the stage. Ever since this event, space debris mitigation has been a major concern for all launcher activities in Europe.After a short recall of the launchers currently operated by Arianespace as well as those currently developed by ESA with CNES, particularly for the safeguard authority, including the most promising future evolutions, the set of applicable regulations is described. These rules are fundamentally derived from the IADC Guidelines (hence the UNCOPUOS ones), translated into European Code of Conduct and in some more applicable Standards, such as the one prepared by ESA. The process of preparing ISO standards, mainly through the ECSS Working Group, is also described.Three major families can be identified: minimization of Mission Related Objects, Passivation of stages at the end of mission, and orbital protected zones including the so-called 25-year rule.The paper describes how European launchers do or will fulfill these applicable standards, quantifying the efficiency of the mitigation rules, and describing improvement actions currently under study.