一种RFID空中接口安全认证算法

射频识别技术是一种非接触式的自动识别技术,对RFID的现有技术进行了分析,对现存问题做了改进,并在此基础上提出了一种空中接口通信安全认证算法,通过ID更新来保证标签的匿名性,并且解决了一般RFID空中接口算法中采用ID刷新机制容易导致的数据更新不同步问题。     

密集环境下RFID系统滤波方法研究

从海量射频识别(RFID)标签数据中滤除冗余标签信息成为RFID应用中亟需解决的问题。读滤波方法标签数据源数量大,滤波效率较低。基于阅读器读滤波算法及空中接口标签群管理方法,提出利用几何方法的空中接口滤波算法;结合读滤波及空中接口滤波算法,提出一种新的RFID系统滤波方法。利用查询概率模型及滤波时间测试方法,对所提出滤波方法进行仿真测试。测试结果表明,相较于读滤波方法,该方法滤波效率提高了50%。     

高空无人机自动加油对接过程轨迹控制研究

针对无人机在高空自动加油对接过程中容易出现偏差的问题,提出了无人机空中自动加油精准对接的优化控制方案,研究并分析了影响加油锥管与受油接口快速准确对接的主要因素,通过运动轨迹生成器对浮锚加油锥套的运动轨迹进行模拟,无人机的自动飞行控制系统根据轨迹跟踪曲线对无人机的飞行姿态进行调整,引导无人机的受油接口与加油锥管进行精确对接,整个飞行轨迹跟踪控制过程优化了复杂高空环境中无人机加油对接的精准性;通过仿真实验表明,该高空无人机加油对接引导方法提高了空中管口对接的速度与抗干扰能力,可以满足各种复杂高空环境的无人机加油任务。     

LTE系统空中接口开销分析

本文主要从带宽保护、CP开销、上、下行链路开销等方面对LTE FDD以及LTE TDD系统的空中接口开销进行了介绍和分析,有助于对LTE系统的无线频谱的使用效率的了解,也有助于LTE网络规划时的系统容量的准确计算.     

某型战斗机嵌入式训练系统设计技术研究

在深入研究现有航电系统架构、飞行员操作程序和接口通信的基础上,阐述某型战斗机加装嵌入式训练系统的必要性.通过对嵌入式训练功能需求进行分析,给出可行的系统功能划分、接口通信方式、数据流和系统设计方案.原理样机通过了航电系统地面综合测试和空中飞行测试,证明已实现设计目标,即充分利用原有航电设备,为飞行员构建真实操作、训练环...     

基于OV7620和FPGA的图像采集系统设计

对微型飞行器空中侦察关键技术进行了研究,探讨了CMOS数字图像传感器应用于空中侦察的图像采集的可行性。以OV7620为数字图像传感器,FPGA为系统控制核心,为微型飞行器完成空中侦察设计了一套可应用于空间狭小环境中的小型化系统。利用Altera公司提供的IPCore,通过I~2C总线初始化OV7620使用Verilog HDL编程在FPGA内部生成RS-232串口接口模块,简化了系统设计,使系统硬件更加紧凑,系统运行更加可靠。     

一种新型的高速IP网络的流量测量体系

网络流量测量是网络管理的基础之一,流量测量体系结构的研究是网络流量测量及其应用的基础和重要环节。对传统的网络流量测量方法的特点进行了分析,对高速网络流量测量中的关键问题进行了研究,采用数据流归并技术,以提高实用性为目的,Linux平台和开源软件的基础上提出了一种新型的基于分布式探针的高速IP网络流量测量体系,并对其构成及特点进行了分析。该测量体系提供了实用的高速测量平台和数据分析接口,具有广阔的应用前景。     

基于AVR的舵机控制器设计

舵机控制器是无人飞行空中机器人中的一个重要设备。本文提出了利用ATmega 16L AVR嵌入式微控制器产生5路PWM信号控制JR舵机的方法。利用定时器的输出比较功能分时产生每路PWM信号的上升沿和下降沿,分辨率达到0.125us。通过测量接收机信号实现了手自动的无扰动切换,通过RS232接口实现了上住机对舵机的控制。     

具有通信功能的电子血压计的设计

随着电子血压计的家庭化,为了对人体的血压值进行长时间的动态监测,我们需将测量的血压值存储起来以便观察分析.但目前市场上的电子血压计大多都没有接口可以与计算机直接进行数据传输.介绍了一种应用于家用电子血压计与计算机进行数据传输的接口方案,采用AVR单片机与9针RS-232串口,实现了血压数据的无失真传输.分析了血压测量方...     

垂线偏差对空中对准航向误差的影响研究

针对性分析了垂线偏差变化对空中对准航向精度的影响.首先给出了常用空中对准降阶滤波模型,分析了垂线偏差变化影响空中对准航向误差的机理.然后通过实测离线数据测试验证了垂线偏差对空中对准航向误差的影响.最后通过误差协方差分析方法仿真了降阶滤波模型在真实世界中的滤波性能.离线测试及仿真结果表明:在给定条件下垂线偏差变化率对航向误差的影响相对其他未建模惯性测量组件误差是主要的,对航向对准误差影响较大,可达0.15°.在中高精度应用中为保证在不同空域内空中对准航向精度考虑采用高精度重力场模型对垂线偏差进行补偿是必要的.     

Linkages between manufacturing strategy, benchmarking, performance measurement and business process reengineering

An empirical analysis is presented for researching linkages between manufacturing strategy, benchmarking, performance measurement (PM) and business process reengineering (BPR). Although the importance of these linkages has been described in conceptual literature, it has not been widely demonstrated empirically. The survey research was carried out in 73 medium and large-sized Slovenian manufacturing companies within the mechanical, electro-mechanical and electronic industries. The resulting data were subjected to reliability and validity analyses. Canonical correlation analysis was used to test six hypotheses.The results confirmed the need for a strategically-driven BPR approach and the positive impact of performance measurement on BPR performance.     

基于正交试验的空间绳网展开参数灵敏度分析

空间绳网的展开效果是空间绳网捕获任务成功的关键所在,而空间绳网展开效果的性能指标和设计参数都数目较多,且单次仿真试验耗时较长,为了避免进行耗时极长的全析因仿真试验,考虑采用正交试验设计方法以减少试验次数.本文针对影响空间绳网展开效果的设计参数开展了灵敏度分析,首先提出了空间绳网展开的性能指标和设计参数,然后基于正交试验设计安排仿真试验,获得了正交试验结果,最后综合运用极差法和方差法,对正交试验结果的各项性能指标依次进行了参数灵敏度分析.通过本文研究,精简了设计参数和待优化的性能指标的个数,为下一步的空间绳网展开参数优化设计打好了基础.     

基于局部类内结构的鉴别性字典学习方法

针对支持向量引导的字典学习(support vector guided dictionary learning,SVGDL)的鉴别约束项只体现了大间隔原理,而没有很好地利用数据空间内在结构信息的问题,提出了一种新颖的鉴别性字典学习方法——基于局部类内结构的鉴别性字典学习方法。该方法结合了大间隔原理和局部Fisher线性鉴别分析作为鉴别约束条件来指导指点学习。通过建立一个局部类内散度矩阵来编码数据空间的分布结构,增强了挖掘同类数据空间局部结构的能力并进一步地表示了编码向量在数据空间中的局部相似性。为了评价提出方法在图像识别上的表现,在几个常见图像数据集上进行了实验。结果表明,提出方法与大间隔方法相比,在平均识别率上有着明显的提高。     

A hybrid multiple copy routing algorithm in space delay-tolerant networks

With the development of technology and applications in space delay-tolerant networks (SDTNs), increasing attention has been paid on the routing technologies between different DTN nodes. This paper proposes a novel hybrid multiple copy routing (HMCR) algorithm that can be applied not only to deterministic space scenarios but also to opportunistic space scenarios. HMCR combines contact graph and delivery probability metrics to make forwarding decisions. In order to verify the new HMCR algorithm’s performance, research work has been carried out to prove its availability in SDTNs. The analysis and simulation results show that, compared with other algorithms such as contact graph routing (CGR), Epidemic, and PRoPHET, the new HMCR algorithm performs well in the areas of message delivery ratios, average end-to-end delays, and transmission overhead, which proves to be suitable for highly dynamic SDTNs.     

GPU4S: Embedded GPUs in space - Latest project updates

Following the trend of other safety-critical industries like automotive and avionics, the space domain is witnessing an increase in the on-board computing performance demands. This raise in performance needs comes from both control and payload parts of the spacecraft and calls for advanced electronics systems able to provide high computational power under the constraints of the harsh space environment. On the non-technical side, for strategic reasons it is mandatory to get European independence on the used computing technology. In this project, we study the applicability of embedded GPUs in space, which have shown a dramatic improvement of their performance per-watt ratio coming from their proliferation in consumer markets based on competitive European technology. To that end, we perform an analysis of the existing space application domains to identify which software domains can benefit from their use. Moreover, we survey the embedded GPU domain in order to assess whether embedded GPUs can provide the required computational power and identify the challenges which need to be addressed for their adoption in space. In this paper, we describe the steps followed in the project, as well as a summary of results obtained from our analyses so far in the project.     

一种新型单循环排序算法

排序是计算机程序设计中一项经常而又重要的操作,研究排序算法具有重要的理论意义和广泛的应用价值。通过对目前常用的几种排序算法的研究,指出它们均为双重循环或多重循环结构设计,借鉴了军队排队列的思想,提出一种只需要单重循环结构即可完成排序过程的新型算法,并进行了编程实现。通过对该算法的时间复杂度、空间复杂度以及稳定性等性能分析,证明该算法对于基本有序的数据排列排序性能优秀,对于数据排列大都是两两错位的排序过程接近最优算法。     

基于相空间重构双参数联合估计的网络流量预测

为了提高网络流量预测精度,提出一种基于相空间重构双参数联合估计的网络流量预测模型.首先采用极限学习机作为网络流量预测算法,然后预测结果优劣指选择相空间重构参数,最后建立单步、多步的网络流量预测模型,并通过仿真实验对其性能进行分析.结果表明,论文模型可以准确获得最优相空间重构参数,显著提高网络流量的预测精度,预测结果明显优于对比模型.     

Decision support system concepts in expert systems: An empirical study

This paper reports on a survey carried out on 67 ES to investigate whether they employ DSS concepts. The author examines several DSS frameworks and proposes a questionnaire model to conduct the survey. The survey data are analysed and the paper concludes that the three fundamental DSS issues: semi-structured task, support, and effectiveness are explicitly applied in ES. It shows also that although both DSS and ES have similar aims, they accomplish them in completely different ways. The differences are in the boundary of problem space and the way to tackle problems.     

Continuous state/action reinforcement learning: A growing self-organizing map approach

This paper proposes an algorithm to deal with continuous state/action space in the reinforcement learning (RL) problem. Extensive studies have been done to solve the continuous state RL problems, but more research should be carried out for RL problems with continuous action spaces. Due to non-stationary, very large size, and continuous nature of RL problems, the proposed algorithm uses two growing self-organizing maps (GSOM) to elegantly approximate the state/action space through addition and deletion of neurons. It has been demonstrated that GSOM has a better performance in topology preservation, quantization error reduction, and non-stationary distribution approximation than the standard SOM. The novel algorithm proposed in this paper attempts to simultaneously find the best representation for the state space, accurate estimation of Q-values, and appropriate representation for highly rewarded regions in the action space. Experimental results on delayed reward, non-stationary, and large-scale problems demonstrate very satisfactory performance of the proposed algorithm.     

基于距离和径向基核函数的加权KPCA分析

针对利用核主成分分析方法处理非线性问题存在对干扰点的敏感性和特征空间中的主成分缺乏明确的物理意义等缺点,提出了一种改进的模糊KPCA(Improved Fuzzy Kernel Principal Component Analysis,IFKPCA)算法,对每个样本点进行加权处理,并利用基于距离的特征核函数和径向基核函数,把特征空间中的重构误差和输入空间的误差对应起来。用算法对2个无干扰和有干扰的数据集进行了仿真实验。同时,对药物代谢的数据进行主成分提取。结果表明,IFKPCA弱化了干扰点对样本分布的影响,表现出较好的鲁棒性;基于距离的特征核函数对样本分布具有较大的依赖性,而径向基核函数对样本分布具有良好的鲁棒性,对药物代谢的应用结果也进一步表明了IFKPCA的有效性和可行性。