军用自动测试设备的发展现状

测试是保证现代装备系统实际性能指标的重要手段。军用自动测试设备是军用电子武器、现代化指挥系统安全运行和准确操作所必需的重要设备。本文介绍了军用自动测试设备的发展现状及在性能测试中广泛使用的ＶＸＩ总线技术。     

ATM网络的视频编码

该文研究了ＡＴＭ网络环境下的视频压缩编码技术。给出了ＡＴＭ网络的视频压缩编码方案,它是以基于小波变换的分层编码和基于遗传算法的矢量量化技术为基础,其中主要讨论了视频的运动估计、优先级的分配和信元的构成、丢失信元的补偿和比特率的平滑及缓冲技术。     

智能ERP系统决策支持子系统设计

提出了智能ERP系统决策支持系统设计方案。叙述了决策支持系统的两个层次的技术手段及五个方面的决策支持信息以及三个关键技术路径。     

An efficient non-dominated sorting method for evolutionary algorithms

We present a new non-dominated sorting algorithm to generate the non-dominated fronts in multi-objective optimization with evolutionary algorithms, particularly the NSGA-II. The non-dominated sorting algorithm used by NSGA-II has a time complexity of O(MN(2)) in generating non-dominated fronts in one generation (iteration) for a population size N and M objective functions. Since generating non-dominated fronts takes the majority of total computational time (excluding the cost of fitness evaluations) of NSGA-II, making this algorithm faster will significantly improve the overall efficiency of NSGA-II and other genetic algorithms using non-dominated sorting. The new non-dominated sorting algorithm proposed in this study reduces the number of redundant comparisons existing in the algorithm of NSGA-II by recording the dominance information among solutions from their first comparisons. By utilizing a new data structure called the dominance tree and the divide-and-conquer mechanism, the new algorithm is faster than NSGA-II for different numbers of objective functions. Although the number of solution comparisons by the proposed algorithm is close to that of NSGA-II when the number of objectives becomes large, the total computational time shows that the proposed algorithm still has better efficiency because of the adoption of the dominance tree structure and the divide-and-conquer mechanism.     

Balloon focus: a seamless multi-focus+context method for treemaps

The treemap is one of the most popular methods for visualizing hierarchical data. When a treemap contains a large number of items, inspecting or comparing a few selected items in a greater level of detail becomes very challenging. In this paper, we present a seamless multi-focus and context technique, called Balloon Focus, that allows the user to smoothly enlarge multiple treemap items served as the foci, while maintaining a stable treemap layout as the context. Our method has several desirable features. First, this method is quite general and hence can be used with different treemap layout algorithms. Second, as the foci are enlarged, the relative positions among all items are preserved. Third, the foci are placed in a way that the remaining space is evenly distributed back to the non-focus treemap items. When Balloon Focus maximizes the possible zoom factor for the focus items, these features ensure that the treemap will maintain a consistent appearance and avoid any abrupt layout changes. In our algorithm, a DAG (Directed Acyclic Graph) is used to maintain the positional constraints, and an elastic model is employed to govern the placement of the treemap items. We demonstrate a treemap visualization system that integrates data query, manual focus selection, and our novel multi-focus+context technique, Balloon Focus, together. A user study was conducted. Results show that with Balloon Focus, users can better perform the tasks of comparing the values and the distribution of the foci.     

HP VEE与自动测试技术

本文结合现代测试自动化的要求,重点讨论了HP VEE及其进行自动测试的软硬件关键技术,并在此基础上给出了基于HP VEE自动测试的实例。     

基于OWPB和LS-SVM的电路板故障诊断系统

针对雷达电路板检修困难的问题,提出了基于最优小波包基和最小二乘支持向量机相结合的雷达电路板故障诊断方法。利用小波变换对采样数据进行去噪处理,通过小波包分解选择最优小波包基提取熵值作为故障特征向量,并作为基于最小二乘支持向量机的雷达故障诊断模型的输入向量,经诊断模型输出后,完成雷达电路板故障诊断。基于此方法设计了雷达电路板故障诊断系统,提高了雷达故障诊断的正确性和效率。     

Flocking based distributed self-deployment algorithms in mobile sensor networks

In this paper, we address a novel deployment problem in isotropic mobile sensor networks. Sensors are to be relocated uniformly in a region of interest (ROI) centered at a target of interest (TOI) which could be stationary or mobile. With the assumption that relative direction of a sensor to the TOI can be recognized or inferred by devices equipped in the sensor, distributed control algorithms based on first-order and second-order dynamic models are proposed for both stationary and mobile TOI situations. The Lyapunov stabilities and coverage guarantee are provided. To further improve the deployment such as coverage holes inside the network and uniformity of the deployment, four assisted rules are also proposed. Then algorithms proposed for the situation of a stationary TOI are extended to anisotropic sensor networks. Simulations demonstrate the effective performances of the proposed algorithms.     

A new liquid crystal lens with axis-tunability via three sector electrodes

A novel liquid crystal (LC) lens with an on-line tunability on focus length and optical axis is proposed in this study. The designed lens has a LC layer sandwiched by two ITO glasses, one of which is patterned with three sector electrodes. With varied sets of pre-designed voltages applied to these three electrodes, the LC lens can not only render focusing effects but also tunability on the optical axis of the lens to an arbitrary axis. A vector-form equation is developed to predict the direction of axis tuning. Simulations are next conducted to predict dynamics of the LCs in the lens and also the focusing and axis-tuning properties of the lens. Important sizes and materials and fabrication process of the lens are determined and optimized based on simulation results. The designed LC lens is fabricated, and then experiments are conducted to demonstrate the performance of the designed LC lens on axis tuning. It shows that the focusing axis of the LC lens can be effectively changed by pre-calculated combinations of three voltages. It is also shown that the average movement of the focal point per applied voltage reaches 4.778?μm/V.     

校园卡管理信息系统的设计与实现

本文分析了校园卡管理信息系统的功能需求,对系统功能模块设计、数据库的设计与实现以及后台信息管理模块的设计与实现,进行了详细的介绍。