Online stable matching as a means of allocating distributed resources

In heterogeneous distributed systems, achieving optimality in both effective use of computational resources (e.g. throughput) and user satisfaction (e.g. response time) is an important unresolved problem. If the users of the system participate dynamically as consumers as well as donors of computational resources, the task of optimizing the exchange of these computational resources leads to a combinatorial problem. As a solution, we propose a novel algorithm, adaptive online stable matching (AOSM). We present experimental data which compare the performance of AOSM with the performance of two alternative algorithms, first-come first-served (FCFS) and fixed-k online.     

Windowing and random weighting‐based adaptive unscented Kalman filter

The conventional unscented Kalman filter (UKF) requires prior knowledge on system noise statistics. If the statistical characteristics of system noise are not known exactly, the filtering solution will be biased or even divergent. This paper presents an adaptive UKF by combining the windowing and random weighting concepts to address this problem. It extends the windowing concept from the linear Kalman filter to the nonlinear UKF for estimation of system noise statistics. Subsequently, the random weighting concept is adopted to refine the obtained windowing estimation by adjusting random weights of each window. The proposed adaptive UKF overcomes the limitation of the conventional UKF by online estimating and adjusting system noise statistics. Experimental results and comparison analysis demonstrate that the proposed adaptive UKF outperforms the conventional UKF and adaptive robust UKF under the condition without precise knowledge on system noise statistics.Copyright © 2014 John Wiley & Sons, Ltd.     

The dimensional effects of windowing on crosstalk for high speed hard disk drive interconnects

As the areal density rapidly changes, the signal reflection increases. In order to avoid the reflection between a magnetic recording head and a read/write driver on hard disk drive interconnects (HDDIs), the windowing technique is used to keep low insertion loss and it causes the higher crosstalk between lines. In this work, the crosstalk on idealized HDDI with windowing is investigated. The crosstalk represented by the scattering parameters calculated by using the full wave simulation software based on finite integral technique. From the results, the improvement of insertion loss and transmission bandwidth (?3 dB bandwidth) can be found when the window percentage is increased. For the 90% windowed structure, these are improved as 4.27 dB at 1 GHz and 4.53 GHz comparing with the conventional structure, respectively. Besides, the crosstalk increases with the increasing of window percentage. However, it can be suppressed up to 5.68 dB in a range of 0.24–1 GHz when the window percentage is 90%. Furthermore, the 90% of windowed structure with 8 mm window pitch possess the lowest crosstalk about 30.22 dB in a range of 0.32–6.4 GHz. In addition, the placing position of windows in a reference plane with a half of the rest length at both ends should be avoided because it increases both crosstalk and insertion loss. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:217–222, 2014.     

振动信号频谱分析中的加窗及加窗幅值修正

在振动信号频谱中,为了消除加窗导致的信号频谱幅度的不一致问题,通常需要对加窗后信号的频谱进行幅值修正。一般情况下,幅值修正过程遵循两个原则：幅值相等原则和能量相等原则。结合航空发动机振动信号处理中的类似问题,遵循幅值相等原则,结合工程实践,通过理论分析和数值仿真分析的方法,提出了一种基于正弦校准信号的加窗幅度修正的方法。该方法利用正弦校准信号频谱的特点,以及相关的信号处理理论和方法分析得出,加窗幅度修正系数为窗函数序列的直流分量。此外,依据该方法给出了5种常用窗函数的加窗幅值修正系数,并用数值仿真的方法对     

抗差自适应Sage滤波及其在组合导航中的应用

针对卡尔曼滤波需要精确已知状态数学模型及其统计特性的问题,提出一种抗差自适应Sage滤波算法.该方法以Sage滤波为基本框架,吸收了抗差估计和自适应滤波的优点,利用Sage滤波开窗法求得观测残差向量和新息(预测残差)向量的协方差阵,由抗差估计方法确定观测噪声协方差矩阵,利用自适应因子调整动力学模型噪声协方差矩阵,以控制观测异常和动力学模型噪声对导航精度的影响.将提出的算法应用到捷联惯性导航(SINS)/合成孔径雷达(SAR)组合导航系统中,并与Kalman滤波和Sage滤波进行比较分析,仿真结果表明,提出的新算法不但能有效地控制观测异常和动态模型异常对状态参数估值的影响,而且能够抵制状态扰动,提高组合导航系统的滤波精度.     

A genetic algorithm optimized Morlet wavelet artificial neural network to study the dynamics of nonlinear Troesch’s system

In this work, a new stochastic computing technique is developed to study the nonlinear dynamics of Troesch’s problem by designing the mathematical models of Morlet Wavelets Artificial Neural Networks (MW-ANNs) optimized with Genetic Algorithm (GA) integrated with Sequential Quadratic Programming (SQP). The differential equation mathematical model for MW-ANNs are designed for Troesch’s system by incorporating a windowing kernel based on Morlet Wavelets as an activation function and these networks are constructed to define a fitness function of Troesch’s system in the mean squared sense. The unknown adjustable parameters of MW-ANNs are trained initially by an effective global search using GAs hybridized with SQP for rapid local refinement of the results. The proposed scheme is evaluated to solve the Troesch’s problems for small and large values of the critical parameter in the system. Comparison of the proposed results with standard reference solutions of Adams method shows good agreement. Validation of accuracy and convergence of the proposed scheme is made using statistical analysis based on a sufficiently large number of independent runs, this is done in terms of performance measures of mean absolute deviation and root mean squared error.     

双层套管开窗关键技术应用

油层套管为139.7 mm的双层套管开窗的难度较大,通过选择窗口位置及开窗方位,计算双层套管之间不同间隙窗口的长度,计算重要的节点,改进双层套管开窗铣锥、斜向器,选择开窗下部钻具组合及确定开窗主要参数、开窗后井眼沿技术套管行走的处理方法等关键技术的分析研究。得出了开窗前应计算或预估出窗口长度;开窗方位选在双层套管间隙较小的部位开窗;应用斜面角度大和斜面硬度高的双层套管开窗斜向器,保证斜向器的导斜角度;开窗或试钻选用适当刚度的下部钻具组合,避免钻具刚度太大导致开窗窗口过长使斜向器导斜角降低太多,丧失应有的导斜能力致使开窗开不出去的现象发生,并保证钻具有一定的稳斜作用;开窗时根据钻井液携带出的铁屑、水泥块、岩屑情况以及进尺情况及时调整参数,确保双层套管有效、快速、安全开窗。     

扩展的DBNS椭圆曲线标量乘算法

椭圆曲线密码体制的快速实现取决于标量乘算法的运算效率。在传统的（2,3）-双基数标量乘算法的基础上,提出了一种新的（2,5）-双基数标量乘算法。实验数据表明,该算法不仅继承了双基数标量乘算法的优点,同时还改进了传统双基数标量乘算法的不足,如预计算时间长和存储空间要求大等问题,使其应用于存储空间较小的领域如智能卡等成为可能。     

读出电路中的开窗口读出方法实现

主要研究了一种应用于读出电路中的开窗口读出方法.详细描述了开窗口读出电路的工作原理,电路功能和逻辑设计,并通过计算机仿真验证了电路设计的正确性.该方法可以实现任意开窗,即从指定像素开始读出,窗口大小、起始地址和读出顺序均可控;不但可以满像素输出保持大的视场,而且可以任意指定图像中的一个区域开窗口读出,大大提高了图像输出的速率.