一种基于盲源分离的DOA估计方法

方位估计和信号恢复分别是水下目标跟踪和识别的前提. 基于平均时间延迟相关矩阵提出了一种复数域盲源分离方法, 在此基础上实现了DOA估计和信号恢复. 实验结果表明, 该方法在同等条件下完成同样的方位分辨要优于多重信号分类(Multiple signal classification, MUSIC)方法.     

数字信号处理的FPGA实现

介绍了三种常见的数字信号处理过程的FPGA实现,包括频率合成、AM调制和FM调制,并进行仿真和硬件下载验证。     

基于HIS的数据仓库建设与OLAP应用

针对医院信息管理系统(HIS)对辅助决策支持不足,提出以HIS为基础建设面向主题的数据仓库,建立基于联机分析处理(OLAP)的医院决策支持系统。该系统采用数据仓库总线架构,通过共享一致维度集成各个相对独立的数据集市。在客户端针对不同的用户环境分别使用数据透视表服务和基于ADOMD的Web系统,极大地提高了系统的灵活性。     

An improved NEH-based heuristic for the permutation flowshop problem

NEH is an effective heuristic for solving the permutation flowshop problem with the objective of makespan. It includes two phases: generate an initial sequence and then construct a solution. The initial sequence is studied and a strategy is proposed to solve job insertion ties which may arise in the construct process. The initial sequence which is generated by combining the average processing time of jobs and their standard deviations shows better performance. The proposed strategy is based on the idea of balancing the utilization among all machines. Experiments show that using this strategy can improve the performance of NEH significantly. Based on the above ideas, a heuristic NEH-D (NEH based on Deviation) is proposed, whose time complexity is O(mn²), the same as that of NEH. Computational results on benchmarks show that the NEH-D is significantly better than the original NEH.     

Knowledge discovery in corporate events by neural network rule extraction

Over the last two decades, artificial neural networks (ANN) have been applied to solve a variety of problems such as pattern classification and function approximation. In many applications, it is desirable to extract knowledge from trained neural networks for the users to gain a better understanding of the network’s solution. In this paper, we use a neural network rule extraction method to extract knowledge from 2222 dividend initiation and resumption events. We find that the positive relation between the short-term price reaction and the ratio of annualized dividend amount to stock price is primarily limited to 96 small firms with high dividend ratios. The results suggest that the degree of short-term stock price underreaction to dividend events may not be as dramatic as previously believed. The results also show that the relations between the stock price response and firm size is different across different types of firms. Thus, drawing the conclusions from the whole dividend event data may leave some important information unexamined. This study shows that neural network rule extraction method can reveal more knowledge from the data.     

Collapse-free thermal bonding technique for large area microchambers in plastic lab-on-a-chip applications

Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length on the order of 1 mm and characteristic thickness on the order of 10–100 μm) without collapse by introducing a holed pressure equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique, two types of large area microchambers [(1) 20 × 10 mm and 40 μm thick and (2) 12 × 2.5 mm and 120 μm thick] with microchannels were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with the help of the HPEP.     

Design and fabrication of an electrochemically actuated microvalve

A microfluidic valve based on electrochemical (ECM) actuation was designed, fabricated using UV-LIGA microfabrication technologies. The valve consists of an ECM actuator, polydimethylsiloxane (PDMS) membrane and a micro chamber. The flow channels and chamber are made of cured SU-8 polymer. The hydrogen gas bubbles were generated in the valve microchamber with Pt black electrodes (coated with platinum nanoparticles) and filled with 1 M of NaCl solution. The nano particles coated on the working electrode helps to boost the surface-to-volume ratio of the electrode for faster reversible electrolysis and faster valve operation. To test the functionality of the microvalve, a simple micropump based on ECM principle was also integrated in the system to deliver a microscopic volume of fluid through the valve. The experimental results have showed that an approximately 300 μm deflection of valve membrane was achieved by applying a bias voltage of ?1.5 V across the electrodes. The pressure in the valve chamber was estimated to be about 200 KPa. Experimental results proved that the valve can be easily operated by controlling the electrical signals supplied to the ECM actuators.     

Ad Hoc网络中一种基于Tabu搜索的低耗单播路由算法

Ad Hoc网络中,节点能量影响网络的稳定性和整个网络的生命周期.因此我们需要在提供可靠QoS服务的同时尽量降低能耗,延长整个网络的生命周期,而保证QoS服务前提下求解低能耗单播路由的算法是一个NP完全问题.针对这个问题,提出一个基于Tabu搜索的低耗单播路由算法,该算法选择延迟作为QoS参数,利用Tabu搜索的集中性与广泛性并存的优点,在保证QoS服务质量的同时尽量减少网络节点平均能量消耗,以提高整个网络的生命周期.仿真结果表明:该算法在延长网络生命周期方面具有良好效果.     

基于Struts和Hibernate的小型门店MIS的设计与实现

通过对一般小型门店业务流程的调研和现有的一些基于struts和Hibemate技术上的进销存系统上的分析,设计和实现了一个小型门店销售系统.在整体架构方面增加了多层设计模式,在数据库方面运用了一个主子表的方法.设计后,该系统效率提高、易于维护、便于扩展,大大减少了数据冗余,用户界面也更加友好.     

一种新的基于遗传操作的改进型遗传算法

交叉与变异是遗传算法的重要操作,提出了一种新的基于遗传操作的改进型遗传算法.采用最优保留和改进的轮盘赌选择方法,通过基因交叉概率控制交叉,根据高斯分布改进了交叉算子和变异算子,保证了算法的全局搜索能力、局部搜索能力及收敛速度.通过标准函数的数值实验,验证了新算法的有效性.