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.     

基于Internet的空分设备远程监视与故障诊断专家系统的研究

简介了远程监视与故障诊断专家系统在国内空分设备中应用的实际意义，着重分析了大型空分设备远程监视与故障诊断专家系统中远程监视模块和故障诊断模块的开发。     

A differential pulsewidth control loop for high-speed VLSI systems

For those adopting double data rate technology systems, the precise system timing plays a crucial role since both rising and falling edges of the system clock signal are used to sample the input data. Due to this requirement, it is necessary to accurately maintain the duty cycle of the clock signal at 50%. For a multistage clock buffer, a pulsewidth control loop (PWCL) circuit was therefore proposed to adjust the duty cycle of its output signal. This paper is aimed at introducing a new proposed differential PWCL (DPWCL) together with investigating its mechanism through a comprehensive theoretical analysis. By taking advantage of a differential topology, the dc offset in generating the control voltage can be removed thereby improving the duty cycle control accuracy. Moreover, the proposed DPWCL employs a low-pass filter to generate the reference voltage so that the DPWCL does not necessitate a 50% duty cycle reference clock.     

一种改进的电子商务系统商品搜索算法

传统的电子商务系统中，使用关键字匹配的算法实现商品搜索的功能，只能得到包含顾客输入关键字的商品。文章以网上书店的实现为例，通过对商品搜索算法的改进，引入模糊系统和文本匹配算法，使得在顾客搜索商品时，不仅显示精确匹配的商品，而且叮以提供与其要求相似的商品，供其参考。这对于商家增加交易机会、发掘潜在顾客、提高个性化服务水平都有很大的促进作用。     

一种具有人工情感的智能控制系统研究

本文阐述了一种具有人工情感的智能控制系统的设计方法,论述了具有人工情感的智能控制系统的体系结构设计和工作流程。该方法可作为研究人工宠物、情绪调节器等行为机制的基础。