基于小波脊线-Hough变换的LFM信号检测

线性调频(LFM)信号是现代雷达广泛使用的一种大时宽-带宽积的低截获概率信号,根据线性调频信号的小波变换特性,小波脊线与瞬时频率的对应关系,提出了一种检测线性调频信号的联合小波脊线-Hough变换方法,该方法首先计算信号的小波变换,得到二维时-频能量分布图,采用脊算法提取信号的小波脊线,然后在小波脊线时-频平面上再进行Hough变换,从而检测噪声中的线性调频信号并估计信号参数.仿真结果证明,此方法可有效地对线性调频类信号进行检测,并且有较好的抗噪声性能.     

Centrifuge-aided micromolding of micron- and submicron-sized patterns

Developed from soft lithography, replica molding has been proven to be a good method to prepare micron- and submicron-sized features. However, the fidelity of the features can be compromised by incomplete feature cavity filling and feature shrinkage during the forming process. In this study, centrifuge-aided micromolding is developed to prepare micron- and submicron-sized ZnO features. By introducing a centrifugal force, the shear-thinning behavior of the suspensions is utilized, and the cavity filling process and the diffusion of trapped air out of the features are accelerated. The drying shrinkage is decreased by increasing the density of the wet nanoparticle packing from the centrifugal process. The centrifugal force improves the fidelity of all the designed features. ZnO ridges from 0.4 μm to 2 μm size and rods of 1.6 μm size are prepared successfully. The wide applicability of this strategy has been demonstrated by preparing ZrO₂ features via the same method.     

An analysis of used lubricant recycling unit in Turkey

In chemical industries such as lube oil recycling units, stakeholders seek to continuously increase the productivity and profitability of the chemical processes to survive in the market. While scholars have investigated technological production options, recycling, and lube oil recycling flows, there is not enough study that evaluates the interplay between the production volume allocation and the recycled oil quality and quantity contingent upon the process temperature and pressure. The results based on a case study in the Kayalar Dorse production in Turkey show that by optimizing the chemical process mix, the volume of the lubricant oil can be increased by 20% at almost zero variable cost increase.     

Design augmentation for response optimization and model estimation

ABSTRACT

In this article, we consider a situation in which an investigator has run an initial screening experiment, has eliminated some inactive factors, and has undertaken a second stage of experimentation in an effort to identify the optimal operating conditions. If sequential experimentation is possible, the standard approach to this problem is to identify the direction of steepest ascent (descent), and to conduct a series of runs in that direction. Once the best operating conditions in that direction are identified, further experimentation in the new neighborhood can be conducted. Unfortunately, this direction may be poorly estimated or irrelevant depending on the magnitude of experimental error and the nature of the underlying response model. We advocate here the use of optimally augmented experiments in the general direction of a ridge trace. We evaluate alternative strategies using simulation and compare the best of these strategies to method of steepest ascent.     

Firework Plots for Evaluating the Impact of Outliers and Influential Observations in Ridge Regression

With many predictors in regression, fitting the full model can induce multicollinearity problems. Thus, ridge regression provides a beneficial means of stabilizing the coefficient estimates in the fitted model. Outliers can distort many measures in data analysis and statistical modeling, while influential points can have disproportionate impact on the estimated values of model parameters. Graphical summaries, called firework plots, are simple tools for evaluating the impact of outliers and influential points in regression. Variations of the plots focus on allowing visualization of the impact on the estimated parameters and variability. This paper describes how three‐dimensional and pairwise firework plots as well as scalable waterfall–firework plots can be used to increase understanding of contributions of individual observations and as a complement to other regression diagnostic techniques in the ridge regression setting. Using these firework plots, we can find outliers and influential points and their impact on model parameters and show how in some applications, the type of analysis used changes the impact of various observations. We illustrate the methods with two examples. Copyright © 2016 John Wiley & Sons, Ltd.     

某引水工程取水口围堰和预留岩坎拆除爆破

某引水工程取水口前端预留岩坎与已建水库相连,距离取水口塔体和已建大坝较近,为确保周边建筑物安全,拆除时先进行预留岩坎迎水坡爆破剥离,减少其厚度,再对混凝土围堰和剩余预留岩坎进行分层分区拆除爆破。爆破施工中采取了有效的安全爆破控制技术措施,降低了施工难度,保证了施工质量,达到了预期的效果。通过分层分区拆除爆破,有效解决了围堰和预留岩坎在大型水库水下淹没深度较深且不需人为降低水库水位进行拆除爆破的难题,为今后类似工程积累了宝贵的经验。     

基于核岭回归方法的定位算法研究

针对无线传感器网络环境下的定位问题,提出了一种基于核岭回归(Kernel ridge regression,KRR)的定位算法。核岭回归算法是在岭回归算法的基础上加入了核函数,该算法在离线阶段采用核岭回归方法提取所有位置指纹数据间的非线性关系,训练出非线性回归定位模型;在线阶段采集目标点的接收信号强度指示（Received signal strength indicator,RSSI）值,利用非线性定位模型估计目标点的物理位置。仿真分析了影响算法性能的各个因素,并在室内典型办公环境下进行了定位实验。实验结果表明,该算法在不同因素的影响下,相比传统加权K近邻算法(Weight K-nearest neighbor,WKNN)算法能达到更好的定位精度,在位置网格间距1.8 m时,WKNN算法平均定位误差为2.53 m,而该算法误差为1.58 m。     

基于离散小波分解和频率脊线分析的CPM信号符号速率盲估计

非合作接收条件下,连续相位调制（CPM,Continuous Phase Modulation）信号多变未知的信号体制使其符号速率盲估计一直是分析该类信号的难点之一.现有的算法大多直接基于信号的瞬时频率或循环平稳性,存在抗噪性能差,不适用于多指数CPM信号等问题.针对该问题,本文通过分析小波变换在信号分解和时频分析中的优势,提出一种综合利用离散小波（DWT,Discrete Wavelet Transform）分解和频率脊线提取的CPM信号符号速率估计的新算法.算法对比分析表明,所提算法具有更好的抗噪性能且在小数据量时也能达到较好的估计性能.     

基于岭最小截平方的传感器稳健配准方法

传感器配准是多传感器数据融合系统获得性能优势的关键前提.受随机噪声、系统误差、虚警、漏报等因素的干扰,传感器配准常常工作在非理想关联环境中,依赖于理想关联假设的传统配准方法性能衰退严重.另一方面,传统传感器配准方法对目标分布场景敏感,当目标密集分布时,配准问题呈现病态性,估计结果数值不稳定.本文重点研究非理想关联及场景病态性共存时的传感器稳健配准问题,提出了系统误差的岭最小截平方（Ridge Least Trimmed Squares,RLTS）估计方法.该方法结合了岭回归（Ridge Regression,RR）与最小截平方（Least Trimmed Squares,LTS）估计的优点,能够有效应对错误关联及病态性的不良影响.仿真实验证实了所提方法的稳健性能.