一种基于双模式虚拟机的多态Shellcode检测方法

近年来,Shellcode攻击通常利用多态技术进行自我加密来绕过网络层设备的检测,而现有检测方法无法区分多态Shellcode与加壳保护代码.提出了一种基于双模式虚拟机的多态Shellcode检测方法,该方法改进了现有的GetPC定位机制,实现了Shellcode的初步定位,通过IA-32指令识别对网络流量的进行进一步过滤,利用有限自动机及其判别条件实现虚拟机控制流模式和数据流模式之间的切换,并通过结合现有的特征匹配技术实现对多层加密的多态Shellcode的检测.实验结果表明,针对大量真实的网络数据,该方法在保证高检测召回率的同时,能够实现对多态Shellcode与加壳保护软件的有效区分,避免了对正常流量的误报行为,并且时间开销介于静态分析与动态模拟之间,为网络层检测多态Shellcode提供了一种有效方法.     

Methodology for capturing and formalizing DFM Knowledge

Design for manufacturing (DFM) practices lead to more competitive products from the point of view of cost, development time and quality. However, the success of considering manufacturing issues during design process would be higher if manufacturing information was more readily available and designers needed less experience to select information relevant to DFM.     

A glance of technology efforts for design-for-manufacturing in nano-scale CMOS processes

This paper overviews design for manufacturing （DFM） for IC design in nano-CMOS technologies. Process/device issues relevant to the manufacturability of ICs in advanced CMOS technologies will be presented first before an exploration on process/device modeling for DFM is done. The discussion also covers a brief introduction of DFM-aware of design flow and EDA efforts to better handle the design-manufacturing interface in very large scale IC design environment.     

Detecting the electrical conductivity of single walled carbon nano-tubes by a DFM detection system

Rare SWCNT materials contain both metallic SWCNT(m-SWCNT)and semi-conducting SWCNT(s-SWCNT).Since mSWCNT and s-SWCNT have very different applications,it is necessary to differentiate them so as to further separate them for more efficient CNT utilization.To achieve this goal,the authors established a dielectric force microscope(DFM)detection system to differentiate s-SWCNT from m-SWCNT,based on different 2 force decided by SWCNT’s conductivity under AC electric field.The experimental results showed that s-SWCNT can be clearly differentiated from m-SWCNT.The statistics analysis shows that the detected number proportion of s-SWCNT to m-SWCNT matches the well-known proportion 2:1 in the normally prepared CNT materials.The above results strongly verified the effectiveness of the detection system.     

Segregation of dockage and foreign materials in wheat during loading into a 10-m diameter corrugated steel bin

Segregation of dockage and foreign materials (DFM) is an unavoidable phenomenon in bulk grain and causes many problems. In this study, distributions of DFM, and shrunken and broken kernels (SBK) were determined during loading of wheat in a 10-m diameter flat-bottom cylindrical bin. Wheat was loaded through a vertical funnel (spout) into the bin from five drop heights (1.6, 2.5, 3.4, 4.3 and 5.2 m). Samples were collected using a sampling tube (29 cm diameter and 50 cm deep) inserted vertically at five locations (0.00, 1.25, 2.50, 3.75 and 5.00 m of horizontal distances from the center) along three radii of the bin for each drop height. The impurities from each collected sample were divided into five categories with different sizes (other grains, other particles, SBK, fine particles, and dust and fragments) by sieving analyses. Impurities larger and smaller than wheat kernels were categorized as large and small impurities, respectively. Drop height significantly influenced the radial distribution of fine particles, dust and fragments, but not the distribution of other grains and other particles. Fine particles and dust and fragments mainly accumulated in the center, while SBK accumulated mostly near the wall of the bin. Both true density and apparent test weight (bulk density) of unclean wheat and test weight of clean wheat significantly changed along the radius of bin. Apparent test weight of unclean wheat was minimum in the center and close to the wall of bin. Drop height did not influence true density and apparent test weight of clean and unclean wheat. Thousand kernel weight, dimensions, and sphericity of wheat kernels were similar at different radial locations of bin for all drop heights. This study can be used as a reference for further studies on grain handling and associated effects on grain grading system and design of aeration, drying, and insect control. .     

基于特征的冲压零件经济性评价数学模型的建立的研究

在对冲压过程进行深入分析研究的基础上,采用制造计分的方法。对冲压零件制造过程中模具成本、冲压时间、冲床选择、冲压设备折旧费用进行了评价,建立了冲压零件经济性评价的数学模型。     

利用6σ手段降低PIP制程的不良率

在PIP制程中,影响产品的最终质量涉及到的因素有很多。文章简单介绍了PIP制程的定义,详细阐述了PIP制程中影响产品不良的因素种类,分析了每一种因素产生的原因及预防措施,并针对这些因素采取6西格玛先进管理方法中的相应对策来分析和解决问题。同时列举了实例,针对主要不良因素加以改善来降低产品的不良率,从而保证产品的质量以获取更大的经济效益。     

SoC、DFM与EDA

介绍了系统级芯片(SoC)、可制造性设计(DFM)和电子设计自动化(EDA)的最新发展动态。SoC正在从单核向双核、四核和多核过渡。SoC设计必须采用DFM和EDA。采用DFM和EDA的优点:(1)提高芯片的生产效率和良率;(2)降低芯片生产成本;(3)缩短芯片生产周期,加速上市。     

DFM软件在PCB设计中的应用

电子产品的可制造性分析正在受到越来越多的重视,但是实施可制造性是个非常复杂的费时费力的过程,通常要具备丰富经验的技术人员付出繁重的劳动,尽管如此,由于人的主观性,很多的问题仍旧遗漏到了新品试制和投产阶段,降低了DFM的效果.正是由于这个现状,华莱公司提供了他们DFM的优秀工具Trilogy 5000,我们结合本公司的实际,重点对其可制造性模块进行了推广应用,使之成为PCB设计之后投产之前进行自动评审的有力工具,提高了单板设计的一次成功率.