经济波动谱分析方法的比较研究

为解决我国经济序列长度较短及各主周期分量难以同时准确分辨的问题，提出加费周期图谱估计与最大熵谱估计相结合的谱估计方法，并将各主要周期分量单独分辨，且通过对序列进行三角函数拟合来确定周期长度准确信。从谱估计曲线、主周期分量的分辨和周期长度的准确性3个方面与一般的谱分析方法进行了比较，说明了该方法的可行性和有效性。     

基于模糊多级时频峰值滤波消减地震勘探随机噪声

为解决时频峰值滤波采用单一窗长无法同时压制随机噪声和保留信号特征的问题,需要针对信号和噪声设置不同长度的窗函数,提出一种基于模糊判别的多级窗长时频峰值滤波方法。该方法结合模糊判决准则,根据地震信号局部时变特征模糊判定地震图像中各像素隶属于有效信号和随机噪声的程度。对于模糊分段后的信号和噪声,分别根据信号频率特征和噪声强度设置多级时频峰值滤波窗长时频峰值滤波算法,在噪声区域采用较长的窗长以压制随机噪声,在信号部分采用较短的窗长以保持地震信号的细节。将模糊多级时频峰值滤波应用于合成记录和共炮点地震勘探记录,结果表明,改进的方法增强了时频峰值滤波算法保持信号特征的能力,能够有效提高地震勘探图像的信噪比。     

基于内存池的应用程序级页面置换算法

计算机处理海量数据时,内外存数据的交换是影响系统效率的关键因素之一。本文在分析系统级页面置换算法不足的基础上,提出应用程序级页面置换的概念,同时详细介绍其在Windows操作系统下的实现,并在人脸识别系统中对算法进行验证,结果表明本算法执行效率优于原始算法。     

Generic windowing support for extensible stream processing systems

Stream processing applications process high volume, continuous feeds from live data sources, employ data‐in‐motion analytics to analyze these feeds, and produce near real‐time insights with low latency. One of the fundamental characteristics of such applications is the on‐the‐fly nature of the computation, which does not require access to disk resident data. Stream processing applications store the most recent history of streams in memory and use it to perform the necessary modeling and analysis tasks. This recent history is often managed using windows. All data stream management systems provide some form of windowing functionality. Windowing makes it possible to implement streaming versions of the traditionally blocking relational operators, such as streaming aggregations, joins, and sorts, as well as any other analytic operator that requires keeping the most recent tuples as state, such as time series analysis operators and signal processing operators. In this paper, we provide a categorization of different window types and policies employed in stream processing applications and give detailed operational semantics for various window configurations. We describe an extensibility mechanism that makes it possible to integrate windowing support into user‐defined operators, enabling consistent syntax and semantics across system‐provided and third‐party toolkits of streaming operators. We describe the design and implementation of a runtime windowing library that significantly simplifies the construction of window‐based operators by decoupling the handling of window policies and operator logic from each other. We present our experience using the windowing library to implement a relational operators toolkit and compare the efficacy of the solution to an earlier implementation that did not employ a common windowing library. Copyright © 2013 John Wiley & Sons, Ltd.     

电力系统高精度频率估计的谱泄漏对消算法

提出基于谱泄漏对消技术的电力系统频率估计方法.该法通过将两段采样起点错开1/4个额定周期的采样信号序列的加窗傅里叶变换将基波的谱泄漏相消,同时也能显著减小其它奇次谐波的谱泄漏对频率测量的影响,从而极为有效地减小因采样不同步及信号畸变而引起的测量误差.由于电力系统频率成分主要为基波分量和小部分奇次谐波,因此该法能够显著地提高频率测量的精度.该法除了估计精度高以外,还具有时滞小和计算量小(只需对采样数据求加权和)等优点,适合于实时高精度频率测量.     

320×240凝视型器件开窗功能在光谱测试中的应用

正常工作模式下的单通道320×240凝视型器件帧周期较长,给红外焦平面器件光谱测试带来新的问题.文中利用320×240读出电路的开窗功能解决了这一问题,从而实现了凝视型320×240器件的光谱测试,并为今后更大规模阵列的测试提供了一种技术途径.     

ECC在商务文档安全传输中的设计与应用*

介绍了椭圆曲线密码体制(ECC)的基本概念及椭圆曲线上的Menezes-Vanstone密码体制,并且对椭圆曲线一种快速点乘算法--固定基点窗口法进行了深入的探讨,用C 实现了该算法.最后给出了商务文档的安全传输中基于Menezes-Vanstone密码体制的加/解密模型.     

256×256CMOS读出电路随机开窗的简易实现

介绍了一种实现CMOS读出电路的随机开窗口的方法。该方法采用译码器的方式实现,与传统的移位寄存器实现读出电路随机开窗相比,该方法的优点是电路结构简单、版图占用芯片面积小、功耗低,以及操作灵活。主要介绍了采用译码器实现随机开窗的原理和电路设计,并给出了相应的仿真波形。     

Implementing a zooming User Interface: experience building Pad++

We are investigating a novel user interface paradigm based on zooming, in which users are presented with a zooming view of a huge planar information surface. We have developed a system called Pad++ to explore this approach. The implementation of Pad++ is related to real-time 3D graphics systems and to 2D windowing systems. However, the zooming nature of Pad++ requires new approaches to rendering, screen management, and spatial indexing. In this paper, we describe the design and implementation of the Pad++ engine, focusing in particular on rendering and data structure issues. Our goal is to present useful techniques that can be adopted in other real-time graphical systems, and also to discuss how 2D zooming systems differ from other graphical systems. © 1998 John Wiley & Sons, Ltd.