一个保护代理人身份的多级代理签名方案

基于RSA签名体制,提出了一个新的可以保护代理人身份的多级代理签名方案。新方案采用影子身份产生中心给每个代理人产生一个影子身份,并用影子身份为消息签名,可确保保护代理人的身份不被泄露,并保证当某个代理人滥用职权时,权威机构可以要求影子身份产生中心根据其影子身份追溯到他的真实身份。同时该方案也满足不可否认性,可区分性,不可伪造性等。     

最大Lyapunov指数实现局域网流量的预测

由于网络中存在复杂的非线性动力学特性,基于混沌理论,采用最大Lyapunov指数对局域网络流量序列进行预测分析,能够实现较早地预测出网络流量的突变特性.首先,采用相空间重构理论,并结合C-C算法将实际测试的流量时间序列投影到重构的相空间中.然后,计算其最大Lyapunov指数并对最大可预测时间进行了分析,同时对预测算法进行了研究.最后,对实际测试的局域网流量序列分别采用点预测和区间预测方法进行了分析.仿真结果显示,采用点预测方法对流量突变可以进行有效预测,突变越剧烈预测越准确;而采用区间预测可以有效预测流量的变化趋势,但不适用于广域网环境.进一步表明此方法能有效地利用所有数据信息进行预测,预测效果准确、可靠,可广泛的用于网络拥塞和网络攻击中.     

利用模糊感知器解决模糊可分样本的分类问题

针对一类用于解决分类问题的模糊感知器,提出完全随机输入的模糊δ-规则,并给出训练样本模糊可分的定义。实例表明,利用该算法可以有效地解决模糊可分样本的分类问题,在有限步迭代后就达到收敛,即有限步训练后网络能将所有样本正确分类。     

Seepage-stress coupling constitutive model of anisotropic soft rock

To provide a seepage-stress coupling constitutive model that can directly describe the seepage-stress coupling relationship, a series of one-dimensional seepage-stress coupling tests on two kinds of soft rock (argillaceous siltstone and brown mudstone) were performed by using an MTS-815.02 tri-axial rock mechanics test system, with which the stress—strain curves according to the seepage variation were obtained. Based on the experimental results and by employing Hooke’s law, the formulation of the coefficient of strain-dependent permeability was presented and introduced to establish a coupling model. In addition, the mathematical expression and the incremental formulation for coupling model were advanced, in which five parameters that can be respectively determined by using the experimental results were included. The calculated results show that the proposed coupling model is capable of simulating the stress—strain relationship with considering the seepage-stress coupling in the nonlinear elastic stage of two kinds of soft rock. Foundation item: Projects(50378069, 50639090) supported by the National Natural Science Foundation of China; Project(50639090) supported by the Joint Fund of Yalong River Hydropower Development, China     

Nonlinear behavior of concrete beams with hybrid FRP and stainless steel reinforcements

The full-range behavior of partially bonded, together with partially prestressed concrete beams containing fiber reinforced polymer (FRP) tendons and stainless steel reinforcing bars was simulated using a simplified theoretical model. The model assumes that a section in the beam has a trilinear moment—curvature relationship characterized by three particular points, initial cracking of concrete, yielding of non-prestressed steel, and crushing of concrete or rupturing of prestressing tendons. Predictions from the model were compared with the limited available test data, and a reasonable agreement was obtained. A detailed parametric study of the behavior of the prestressed concrete beams with hybrid FRP and stainless steel reinforcements was conducted. It can be concluded that the deformability of the beam can be enhanced by increasing the ultimate compressive strain of concrete, unbonded length of tendon, percentage of compressive reinforcement and partial prestress ratio, and decreasing the effective prestress in tendons, and increasing in ultimate compressive strain of concrete is the most efficient one. The deformability of the beam is almost directly proportional to the concrete ultimate strain provided the failure mode is concrete crushing, even though the concrete ultimate strain has less influence on the load-carrying capacity. Foundation item: Project (50478502) supported by the National Natural Science Foundation of China     

Electroless nickel plating on the surface of carbon fibers

The electroless nickel plating on the surface of carbon fibers was prepared by pretreating the carbon fibers in order to increase their conductivity,and consequently enhance the EMI shielding effectiveness of the composites.The relationship between the performance of depositing coat and pH value,temperature,reaction time and the way of agitation was studied.Results show that the depositing quality is stable under pH between 4.5 and 5.0,temperature between 75 ℃ and 85 ℃,reaction time for 10 min and air agitation.The uniform and compact nickel layer deposited on carbon fibers was proved by XRD and SEM,and the electrical resistivity of carbon fibers with nickel coating was tested.Results indicate that the electrical resistivity of carbon fibers with electroless nickel plating is decreased by an order of magnitude compared with that of carbon fibers.It means that nickel coating can greatly improve the electromagnetic interference shielding properties of carbon fibers.     

Novel fluorescence sensor based on covalent immobilization of 3-amino-9-ethylcarbazole via electrostatically assembled gold nanoparticle layer

A novel technique of immobilizing indicator dyes by electrostatic adsorption and covalent bonding to fabricate optical sensors was developed. 3-Amino-9-ethylcarbazole (AEC) was attached to the outmost surface of quartz glass slide via aminosilanizing the slide, crosslinking chitosan, adsorbing Au nanoparticle, self-assembling HS(CH₂)₁₁OH, and coupling AEC. Thus, an AEC-immobilized optical sensor was obtained. The sensor exhibits a wide linear response range from 7.0×10⁻⁷ to 1.0×10⁻⁴ mol/L and a correlation coefficient of 0.995 9 for the detection of 2-nitrophenol. The detection limit and response time of the sensor are 1.0×10⁻⁷ mol/L and less than 10 s, respectively. The fluorescence intensity of the used sensor can be restored to the blank value by simply rinsing with blank buffer. A very effective matrix for immobilizing indicator dye is provided by the proposed technique, which is adaptable to other indicator dyes with amino groups besides AEC. Foundation item: Project(20775010) supported by the National Natural Science Foundation of China; Project(208095) supported by the Key Project of Ministry of Education, China; Project(07A006) supported by the Scientific Research Fund of Hunan Provincial Education Department, China; Project(07JJ3020) supported by Hunan Provincial Natural Science Foundation of China     

火电机组厂级负荷优化算法的比较

分析了目前国内火电机组厂级机组间负荷优化分配算法的研究现状.针对国内常见的火电机组类型和组合方式,在对常用算法进行分析和比较后,对各种算法的优劣和适用范围进行总结,并对今后火电机组厂级负荷优化的研究和应用提出展望.     

运动目标噪声源识别方法

文章提出了利用单线列阵确定运动目标噪声源部位和特性的方法,并提出了基于DOA解算运动目标噪声源的空间位置的方法.介绍了噪声源部位识别时MUSIC近场和相关性处理方法.数字仿真计算、消声水池模拟试验和实物试验结果表明,文中所介绍的方法是正确的.当运动目标和测试阵垂直距离小于150 m时,噪声源部位测试误差不大于0.1 m,可用于工程测试.     

基于S3C2410的无线抄表手持终端的设计

研究提出并初步实现了一种基于GPRS无线通信技术的三级架构的远程抄表系统,基于三星S3C2410微处理器的无线抄表手持终端为远程抄表系统的核心．无线抄表手持终端实现了家用三表信息的远程抄送,弥补了传统抄表的不足,增加了自动抄表的灵活性．