网络安全事件的关联分析方法的比较研究

随着当前攻击手段和技术的日益复杂化,一次入侵事件往往需要多个步骤才能完成,这些步骤都是彼此相关的。但是传统的入侵检测集中于检测底层的入侵或异常,所检测到的结果也仅仅是一次完整入侵的一部分,所以不能将不同的报警结合起来以发现入侵的逻辑步骤或者入侵背后的攻击策略。关联分析技术将不同分析器上产生的报警进行融合与关联分析,极大地减少了报警的数量,降低了入侵检测的误报率,并且适当的减少了入侵检测的漏报率。文中在对网络安全事件关联分析方法的系统结构进行分析后,着重介绍了当前比较流行的几种网络安全事件关联分析方法,最后对各种方法进行了比较研究。     

Extracting Light from Polymer Light‐Emitting Diodes Using Stamped Bragg Gratings

In this paper, we describe a method for increasing the external efficiency of polymer light‐emitting diodes (LEDs) by coupling out waveguided light with Bragg gratings. We numerically model the waveguide modes in a typical LED structure and demonstrate how optimizing layer thicknesses and reducing waveguide absorption can enhance the grating outcoupling. The gratings were created by a soft‐lithography technique that minimizes changes to the conventional LED structure. Using one‐dimensional and two‐dimensional gratings, we were able to increase the forward‐directed emission by 47 % and 70 %, respectively, and the external quantum efficiency by 15 % and 25 %.     

加入WTO后对中国会计业的影响

中国政府已于2001年12月正式加入做为当代世界规范和经济贸易关系最具权威的国际性组织WTO.加入WTO,对中国来说既是机遇,同时又是挑战,它的影响是全面的、全方位的.而对于中国会计业的影响也是深刻的,中国经济、中国企业要走向世界,中国的会计业也必须直面世界,按国际惯例行事,因此,深刻研究和分析加入WTO后对中国会计业的冲击、挑战以制定相应的政策、方针、准则就显得非常的迫切.     

烧结工艺对液相合成（SrPb）TiO3基陶瓷热敏特性影响的研究

本文在液相合成（ＳｒＰｂ）ＴｉＯ３粉的基础上，研究了升温速率、保温时间、烧结温度及降温方式对（ＳｒＰｂ）ＴｉＯ３基陶瓷的Ｖ型ＰＴＣ热敏特性的影响。实验表明：升温速率对其热敏特性影响不大，保温时间和烧结温度的作用是一致的，具有一最佳范围。而降浊方式对材料的热敏特性影响较大。综合各因素的影响，本配方中，样品的烧结制度定为：以２００℃／ｈ的速率升温，在１２５０℃保温１ｈ，炉冷至９５０℃，保温０．５ｈ，再     

大系统分散鲁棒容错控制的进展及主要成果

综述了近２０年来关联大系统分散鲁棒容错控制的研究动态及取得的主要成果。说明了统一地研究分散鲁棒容错控制的必要性。在分散控制、鲁棒控制和容错控制研究领域内，分析了各种设计方法的主导思想及实质；指出了这些研究成果的意义与存在的问题。文中着重论述了分散、鲁棒、容错控制研究方法的发展途径。     

Modeling and CW operation of a quasi-three-level 946 nm Nd: YAG laser

A model is developed for an end-pumped quasi-three-level laser with population in the lower laser level at equilibrium such as for transitions to the manifolds⁴I9/2in Nd³⁺,⁴I15/2in Er³⁺,⁵I8in Ho³⁺and³H6in Tm³⁺. It is shown that the effect of residual lower laser level population on laser operation can be treated as a saturable loss. Room temperature operation on the⁴F3/2-⁴I9/2transition in Nd:YAG under CW dye laser pumping has been demonstrated with a threshold as low as 11.5 mW incident power and a slope efficiency of 7 percent with 0.3 percent output coupling. Performance is limited by the low output coupling and diffraction loss.     

地壳应力场和密度场资料在油气检测中的应用

依据卫星轨道摄动测量结果反演的地壳区域构造应力场和密度场资料，可圈定油气区域构造圈闭和储集油气的低密度层。计算绘制了闽江口扇形洲区域构造应力场和密度卫星遥感图，图上显示出东海近海闽浙中拗陷含油气带与温东丽水油气构造带相接，敖江口官岭与闽江口川石储岛沥青苗等迹象都在此范围内，在闽江口扇形洲东部沿海沙泥沉积区，邻区东海宽长带深厚海沙软泥沉积区及本区北部罗源湾，用大地电磁CSAMT检测到1000－3000m深度范围内的低阻率地层，与本区卫星遥感图图低密度场相符。     

Effect of misalignment on electrical characteristics of ACF joints for flip chip on flex applications

The effect of misalignment on the electrical properties of anisotropic conductive film (ACF) joints is investigated in this work. It is found that along with the increase of misalignment, the connection resistance of ACF joints increases. When the misalignment in x-direction is less than 5 μm, the increase rate of connection resistance is quite large. Then, along with the severity of misalignment, the increase rate becomes smaller. Finally, when the misalignment is close to 20 μm, the increase rate rises again. The Holm's electric contact theory is used for understanding the connection resistance variation. On the other hand, with the increase of misalignment in x-direction, the insulation resistance between ACF joints decreases. If the misalignment exceeded 10 μm, the decrease is prominent for the Ni particle ACF joints. This phenomenon can be explained by the effect of dielectric damage of the epoxy.Computer programs are also developed to calculate the variation of the probability of open and shorting after misalignment and predicate the maximum misalignment tolerance. The results show that the open and shorting probability increase abruptly after misalignment. On the view of pad parameters, the open probability is mainly related to the pad area, while the pads gap is critical to the shorting probability. Large pads gap (small pad width) can reduce the shorting probability obviously. On the other hand, enlarging the pad area by increasing pad length decreases the open probability significantly. So comparing to square shape pad, rectangle shape pad can reduce the failure probability greatly.     

基于PⅢ工控机VI测控系统远程控制研究

虚拟仪器（VI）将计算机采集测试分析引入到电子测量领域，用数字化和软件技术极大地提高了测量的灵活性。而VI远程测控系统是网络技术、通信技术一计算机虚拟技术结合的产物。远程控制技术能够使操作突破地域的限制，已在网络环境下PⅢ工控机上实现。     

A dual-mode multiuser detector for DS-CDMA systems

We introduce a dual-mode multiuser detector that dynamically switches its detection mode between matched-filter and decorrelator operations based on the channel characteristics. This detector significantly reduces the overall computational requirement while maintaining similar performance as that of the decorrelator. The switching mechanism of our dual-mode detector is designed by exploiting the performance-complexity tradeoff between the decorrelator and the matched-filter. Extensions of this idea to other types of multiuser detectors are also proposed