ARCE风险处理计划测量模型的设计与实现

提出用于定量测量风险处理计划有效性的ARCE模型,从理论上证明该模型的正确性.以组织信息安全资产的风险值和已实施控制措施为输入,通过中间变量矩阵得到风险处理计划有效性矩阵的模型量化指标体系.模型实现过程包括风险评估、风险处理、定量测量、安全事件管理和报表5个部分,并给出实施流程.应用结果表明,该模型能准确测量风险处理计...     

Examining different types of collaborative learning in a complex computer-based environment: A cognitive load approach

This study compared the effects of two collaborative learning strategies (Open-ended and Task-based) with an individualized learning strategy on individual learning in a computer-based environment. The experiment sought ecological validity by conducting it under real teaching and homework conditions. Ninety-four students from grade 9 participated in a webpage design task. Cognitive load theory was used to predict that the collaborative approaches would outperform the individualized approach due to reduced cognitive load. This hypothesis was confirmed by performance scores and cognitive load only in the case of the Open-ended collaborative learning condition. Evidence was also found that the Open-ended collaborative learning condition outperformed the Task-based collaborative one. It was concluded that in collaborative learning a more Open-ended task design together with moderate independent sub-task requirements leads to more effective learning.     

Response time of thermal flow sensors with air as fluid

Due to their fast response time miniaturized thermal flow sensors can be applied well for the measurement of instationary gas flow. For some applications, the response time of the sensor must be known with high accuracy. We investigated three methods for response time determination with air: a jump of temperature induced by electric heating, a gas velocity step made by a membrane burst and acoustic phase shifts between sound velocity and sound pressure (standing and traveling waves). The measurements have shown that the response time of thermal flow sensors is a function of flow velocity. For stagnant flow, the thermal response time is about 4.5 ms for our thermal flow sensors. With increasing flow from the heater to the thermopiles, the heat transfer rises. Thus, the response time is faster and decreases to about 1 ms.     

Measurement of oocyte temporal maturation process by means of a simple optical micro-system

We present a simple optical micro-system used to measure the transmission spectra of oocytes in order to qualify their maturation stage. Two applications of the device are possible: (i) the evaluation of the maturation stages of oocytes, and (ii) the development of a fertilization indicator. For the first application, GV, MI and MII oocytes were also analysed. Transmission spectra allow the 3 maturation stages to be identified but cannot be used to estimate the maturity of an unknown oocyte. Oocytes are subject to continuous development. This is why spectral separation of the 3 maturation stages cannot be made although they can be visually identified. However, the visual observation remains biologist-dependent. We therefore investigated the temporal maturation evolution of the oocytes in terms of transmission spectra and probability analysis. Results show that oocytes to be fertilized should not only be chosen in the MII stage, but also at the right time during the MII stage. This particular aspect requires further investigation. However, spectral measurements could be used as a technique for monitoring the maturation evolution of the oocytes. Fertilized oocytes exhibiting fertilization abnormalities were also tested. The device proved to be an efficient fertilization indicator.     

基于交互式马尔可夫链的可信动态度量研究

可信动态度量为保障可信计算平台的可靠运行提供了重要支撑.根据系统的可靠性、可用性、信息和行为安全性,提出了可信度量要达到的目标.当前的可信度量集中在可信功能度量上,基于交互式马尔可夫链增加性能特征指标度量,即在预期行为描述模型中,运用变迁系统模型描述功能预期,通过将体现在可靠性上的路径概率与预期的关联,获取完成特定行为...     

信息安全视角下的C~4ISR系统耦合性研究

针对以耦合率为指标之一的C4ISR系统体系结构设计合理性验证评估问题,从功能系统间交互信息的安全性需求出发,通过推理揭示出密钥关系的耦合本质,进而提出并分析了密钥关联耦合的概念及其属性。给出了密钥关联耦合的定量度量方法,采用该方法能在体系结构设计结束后就实施并完成度量,且不必考虑密码算法及密钥长度等细节问题。利用Briand等人提出的准则证明了度量方法的科学性与合理性,并结合案例说明了度量方法的可行性与易操作性。     

高阶张量信号的稀疏表示

为了有效地压缩多线性信号,提出了高阶张量信号的稀疏表示框架。基于提出的张量信号的稀疏性度量准则,建立了张量信号稀疏表示的模型。并对于所建立的模型,设计了交替式求解方法。在交替式方法中,先将每个优化问题分解为若干个有次序的非凸子优化问题,再利用组织进化算法来求解这些子优化问题。实验结果表明,当交替式方法运行信号的阶数次时,模型的解已非常接近平稳点,同时有效地获得了信号的稀疏表示。     

加权观测融合非线性无迹卡尔曼滤波算法

针对非线性系统的无迹卡尔曼滤波器(UKF),应用加权最小二乘(WLS)法,提出了加权观测融合UKF滤波算法.证明了加权观测融合UKF滤波算法与集中式观测融合UKF滤波算法在数值上的完全等价性,因而具有全局最优性.一个带两传感器非线性系统的仿真例子说明了两种融合算法的有效性及等价性.     

基于伪测量的分布式最优单步延迟航迹融合估计

融合中心如何处理无序局部数据,对分布式多传感器系统的运行品质至关重要．本文将系统中的局部估计转化为伪测量,将分布式融合估计转化为二级集中式融合估计．将所得的伪测量兼分布式融合估计算法与单步延迟的无序测量数据（out-of-sequencemeasurements,OOSM）最优滤波-A1算法进行组合,得出了分布式多传感器系统的最优单步延迟无序航迹（out-of-sequence tacks,OOST）估计算法,适用于航迹无序局部数据融合估计．该算法具有最优估计性能．     

运输机起飞性能试飞测试技术

运输机进行局部改装后,其结构和气动外形发生了变化.起飞性能是飞行试验中一项重要考核项目,通过构建基于地面光电测试和机载影像测试的综合测试系统,对飞机起飞过程中一台发动机停车情况下的两种处理方式(即中断起飞和继续起飞)进行试飞测试,精确获取飞机的运动参数.通过对实测参数、运动影像以及机载信号量等信息比对分析,得出试验结果...