基于手写签名的电子公文安全认证方案设计

针对基于数字签名的电子公文安全认证中存在的不安全因素,提出一个基于手写签名的电子公文安全认证方案。该方案把人体生物特征即在线手写签名和数字签名相结合进行身份认证,可以有效抵御认证过程中潜在的各种攻击,同时利用信息隐藏技术进行安全通信,为电子公文安全提供可靠保障。     

基于手写签名的电子公文安全认证方案设计

针对基于数字签名的电子公文安全认证中存在的不安全因素,提出一个基于手写签名的电子公文安全认证方案.该方案把人体生物特征即在线手写签名和数字签名相结合进行身份认证,可以有效抵御认证过程中潜在的各种攻击,同时利用信息隐藏技术进行安全通信,为电子公文安全提供可靠保障.     

面向协同设计的高效自证明多重签名方案

为解决协同设计环境中现有多重签名方案存在的工作效率较低和资源占有率偏高等问题,提出并实现了一种基于椭圆曲线密码体制的高效多重签名方案.通过引入公钥自证明思想和预计算步骤,将用户身份认证和数字签名验证有机结合在一起,无需繁琐的身份鉴别认证操作,也无需可信数字认证中心,只需要一次操作即可直接完成数字签名的验证工作.分析及实验表明,该方案结构简单,能有效抵抗目前已知的各种攻击,具有较高的工作效率、较低的资源占有率和较强的安全性.     

基于移动代理的复合服务安全方案

给出了用于基于移动代理(Agent)的服务复合的安全方案.该方案以双线性对为基础,利用有隙Dif-fle-Hellman问题的难解性,构造了一个新的数字签名方案,在进行数字签名时不要求移动Agent携带签名密钥,避免签名密钥被窃取.此外,该方案也保证了移动Agent所携带的服务操作参数信息的完整性.同时因其基于身份的特点,在验证Agent生成的签名和Agent的数据完整性时不需要与认证中心或密钥分发中心进行通信.     

一种制造网格环境下的用户代理的签名方案

为提高制造网格环境下用户代理签名的安全性和性能,构建了一种密钥进化的基于身份的签名方案.在该方案中,使用前向安全来解决用户代理的私钥泄漏问题,并在随机Oracle模型下,基于计算Diffie-Hellman假设,形式化证明其安全性;引入基于身份密码学来改进效率,并基于完全二叉树构建,计算复杂度最多是总时间周期的对数;由用户代理自身来更新签名密钥,真正避免了网格用户必须经常在线;而且私钥更新具有前向安全性,当前的私钥泄漏,不会影响以前时间段签名的安全.     

无可信PKG的基于身份的批量群签名

针对密钥托管困难的问题，对已有的基于身份的群签名的密钥生成算法及签名方案进行了改进，提出了无可信密钥生成中心（PKG）的基于身份的批量群签名方案，其主要利用了椭圆曲线上的双线性映射及批量签名的思想。研究结果表明，与已有相关文献相比，该方案在效率、安全性等方面都有了明显的提高。     

身份可追查的抗合谋攻击广义虚拟企业信任交互方案

现有的虚拟企业信任交互方案,均不能抵抗盟主与盟员及盟员与盟员间的合谋攻击,也不具备盟员间出现信任纠纷时的身份追查功能.为此,提出了一个身份可追查的抗合谋攻击广义虚拟企业信任交互方案.新方案通过在证书签发过程中引入签名成员的固有公私钥信息实现抗合谋攻击,通过构建身份跟踪数据库和y值吊销列表实现责任追查,通过部分签名验证实现错误定位.分析表明,新方案不仅具备已有方案的安会特性,还具备抗合谋攻击和身份可追查功能,且能灵活适应虚拟企业的不同组织模式,为虚拟企业盟员间的信任交互提供了安全可行的解决方案.     

CAD系统中签名管理的设计与实现

利用公开密钥数字签名技术 ,针对 CAD系统中签名的要求提出了一种有效的解决方案 ,即集中式密钥管理技术 ,并给出了相应的实现方法。     

面向网络化制造环境的多功能门限数字签名

为了保证网络化制造环境中信息交换的基本安全需求,提出一个全新的多功能门限数字签名方案.该方案通过结合门限、信息隐藏和指定验证者三种方法,使其不但具有门限签名的功能,可以满足特殊情况下的多人签名,而且能够隐藏信息、指定信息恢复者和签名验证者,实现以多用户协作的方式对共享信息的真实性和来源进行认证.在随机预言模型下,证明了方案的安全性,并给出严谨的数学推导和安全强度下限.最后,通过与相关方法的对比,说明了该方案的有效性.     

高校网络安全审批系统的设计与应用

针对目前高校网络上发布新闻人工送审的烦琐和效率低的问题,讨论并设计了新闻稿审批系统.结合工作流技术构建了新闻稿审批系统的模型,采用数字签名机制对新闻稿审批人员的权限认证,保证各审批环节新闻稿的真实、完整,并采用密钥集中管理的思想,保证签名密钥的安全和使用方便.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.