Cryptanalysis of Two Pseudo-attacks from the Same Mathematic Mistake

Yang and Shieh proposed a timestamp-based password authentication scheme. Fan and Shen gave different improvements on it. Wang claimed that Fan's improvement is insecure and gave his attack. Yang did the similar things on Shen's scheme. This paper gave further cryptanalysis on Wang's and Yang's attacks and pointed out that both of their attacks are infeasible. Wang and Yang made the same mathematic mistake and their attacks are pseudo.     

A General Attribute and Rule Based Role-Based Access Control Model

Growing numbers of users and many access control policies which involve many different resource attributes in service-oriented environments bring various problems in protecting resource.This paper analyzes the relationships of resource attributes to user attributes in all policies, and propose a general attribute and rule based role-based access control(GAR-RBAC) model to meet the security needs. The model can dynamically assign users to roles via rules to meet the need of growing numbers of users. These rules use different attribute expression and permission as a part of authorization constraints, and are defined by analyzing relations of resource attributes to user attributes in many access policies that are defined by the enterprise. The model is a general access control model, and can support many access control policies, and also can be used to wider application for service. The paper also describes how to use the GAR-RBAC model in Web service environments.     

脉冲激光沉积 ZnO 薄膜的微结构及发光性能

用波长为1064nm的Nd—YAG激光器，在氧的活性气氛中，通过激光烧蚀Zn靶在Si（111）衬底上获得ZnO薄膜．用电子显微镜（XRD和FESEM）表征ZnO薄膜的结构和表面形貌，用光致发光谱表征光学性质．实验中观察到紫外光发射和深能级的黄绿光发射．紫外光发射是ZnO薄膜的固有性质，深能级光发射是由于存在氧反位缺陷（OZn）．紫外光发射和深能级光发射的强度依赖于薄膜的表面粗糙度．表面粗糙度在nm级范围内的ZnO薄膜可以获得高强度的紫外光．     

Image Segmentation Using an Improved Watershed Algorithm

IntroductionOne of the firstand mostimportantoperationsin image analysis and computervision is image seg-mentation.The aim of image segmentation is thedomain- independent partition of the image into aset of regions,which are visually distinct and uni-form…     

下颌桩核基牙式全口覆盖义齿基托及支持组织的应力分析

目的　分析下颌桩核基牙式全口覆盖义齿基托及其支持组织的应力分布状况 ,为临床工作提供实验依据和指导。方法　应用三维有限元法研究下颌桩核基牙式全口覆盖义齿基托及支持组织的应力分布特点 ,计算基托、黏膜、皮质骨的应力值并与自然基牙作对比分析。结果　基托在基牙周围有明显应力集中 ;双侧磨牙区牙槽嵴顶处的黏膜应力值相对较大 ;皮质骨主要承受压应力 ,在基牙周围有明显应力集中。结论　基托在基牙处易折裂 ;基牙周围皮质骨受力较大 ,易发生骨吸收 ;桩核对义齿基托及黏膜的应力分布无明显影响 ,对皮质骨的应力分布有一定影响     

A Detailed Chunk-Level Performance Study of Web Page Retrieve Latency

IntroductionIn adaptive web content delivery, two mainareas of research are the “world-wide-wait”(oruser' s retrieval latency) problem and the value-added intermediary services provided in the activenetwork[1,2]. Sometimes, intermediary services arealso related to the latency problem because theyperform content optimization (such as compre-ssion) for faster content delivery.User' s retrieval latency for web page is alwaysa big concern to most Internet content and serviceproviders. The argum…     

xPC目标环境下CAN卡驱动模块的开发

使用xPC目标可以将一台PC兼容机制转变为一个实时系统,基于CAN总线技术的硬件在环测试平台建立ESP系统可使其开发比传统方法更加方便、快捷.由于在xPC Target模块中没有可直接调用的CAN PCI一1680U的驱动模块.因此利用S-function编写了xPC Target下可调用的驱动模块,并应用于ESP硬件在环试验台中,完成了ECU与传感器之间的CAN通信任务.     

S6P形貌仪改进和缸筒珩磨表面评定方法的应用

阐述了使用改进型S6P表面形貌测量仪,结合轮廓支撑长度率tp-2、微观不平度十点高度Rz、轮廓波度Wt等主要参数作为一种新的评定方法,应用于发动机缸筒珩磨表面微观质量的评定,评价了上述参数的最佳范围以及对发动机机油消耗量的影响。     

现浇连续梁桥同步顶升设计

整体同步顶升技术是桥梁改建的重要方法,通过对某现浇连续箱梁桥的实例剖析、方案比选,对顶升设计的要点进行了分析。     

轿车铝缸体的压铸生产

通过对雅阁轿车2.0L、2.3L直列式四缸发动机缸体的生产实践，介绍了采用压铸工艺生产轿车发动机缸体应具备的生产条件和生产线布局形式，分析了其生产工艺的特点、产品质量控制要素和模具设计思路。同时，探讨了模具和压射工艺对产品的影响。