改进的乘性噪声去噪算法

文章在AA模型的基础上,提出了一种改进的图像去噪算法。针对AA模型在去噪时边缘信息对噪声敏感且易出现过平滑的缺陷,在新模型中引入自蛇函数,使得新模型根据图像的特征进行平滑,从而更好地保护边缘信息。数值实验表明,新算法无论是在峰值信噪比上还是在视觉效果上都有很大改善。     

房地产调控政策真的有效吗？--调控政策对预期与房价关系的调节效应研究

为防止房地产市场的过度泡沫化,国家出台了一系列房地产调控政策。但这些调控政策能否有效降低房价并抑制房地产泡沫呢？以往房地产泡沫的研究表明,投资者预期对房地产价格波动和房地产泡沫的影响极为重要。经典的噪声交易模型也指出,噪声交易者预期是房地产价格波动和房地产泡沫形成的重要因素。在系统回顾文献的基础上,文章分析了噪声交易者预期对于房地产价格泡沫的影响,并剖析了房地产调控政策对噪声预期和房价关系的调节作用,从而构建了相应的调节作用模型。在此基础上,使用35个大中城市2002-2011年的实际数据进行了调节作用模型的实证检验。实证结果显示,近年来国家出台的房地产调控政策在抑制房地产价格异常波动和房地产泡沫问题上收效甚微。     

图像分割技术在煤矿生产中的应用

由于煤矿领域特殊的应用环境,常用的图像分割技术直接对煤矿井下视频监控图像的分割往往得不到理想的效果。本文针对煤矿应用领域的环境要求,对常用的几种图像分割算法进行深入比较分析。     

Aspects of second‐order analysis of structured inhomogeneous spatio‐temporal point processes

Statistical methodology for spatio‐temporal point processes is in its infancy. We consider second‐order analysis based on pair correlation functions and K‐functions for general inhomogeneous spatio‐temporal point processes and for inhomogeneous spatio‐temporal Cox processes. Assuming spatio‐temporal separability of the intensity function, we clarify different meanings of second‐order spatio‐temporal separability. One is second‐order spatio‐temporal independence and relates to log‐Gaussian Cox processes with an additive covariance structure of the underlying spatio‐temporal Gaussian process. Another concerns shot‐noise Cox processes with a separable spatio‐temporal covariance density. We propose diagnostic procedures for checking hypotheses of second‐order spatio‐temporal separability, which we apply on simulated and real data.     

基于Takagi-Sugeno-Kang模糊集合的噪声干扰检测方法

为识别混合在接收机热噪声中的人为噪声干扰信号,提出了基于TSK(Takagi-Sugeno-Kang)模糊集合的干扰检测方法。首先将无干扰环境下信道热噪声数据和有人为噪声干扰下的混合噪声数据组合成训练数据序列,利用训练序列对TSK模糊集合模型进行训练,调节模型中规则的多项式系数,使TSK模糊模型对接收信号中的噪声特性与干扰判决之间建立确定函数关系,实现对噪声干扰的检测。通信电台的实验验证表明:尽管接收机的自动增益控制将外部噪声干扰缩小到与本机噪声相当水平,所提方法仍能有效检测出信道中是否有人为噪声干扰存在。     

克服噪声不确定度的拟合优度检验频谱感知算法

针对已有的基于拟合优度(GoF)检验的频谱感知算法易受到噪声不确定度影响的问题,利用矩估计法或特征分解估计法对噪声方差进行实时估计,将采样数据处理为标准正态分布的信号,最后通过GoF检验来感知主用户的存在性。在减小GoF算法复杂度的同时,克服了噪声不确定度对算法性能的影响,仿真结果也表明了所提算法的有效性。     

Monetary valuation of aircraft noise: A hedonic analysis around Amsterdam airport

In densely-populated countries and in particular in large metropolitan areas, the presence of so much human activity causes all sorts of negative externalities, for example traffic noise disturbance. These externalities call for corrective measures by the government. Economists have developed a number of procedures that provide reasonable estimates on the monetary value of some amenities and externalities. In this paper we develop a spatially-explicit hedonic pricing model for house prices in order to quantify the social cost of aircraft noise disturbance in monetary terms. While focusing on aircraft noise around Amsterdam airport in the urban fringe of the Amsterdam region, a key point in our analysis is that we account for background noise. We do this by taking multiple sources of traffic noise (i.e. road, railway and aircraft noise) into account simultaneously and by setting threshold values for all three sources of noise above which sound is generally experienced as nuisance. Based on our regression results we conclude that a higher noise level means ceteris paribus a lower house price. Air traffic has the largest price impact, followed by railway traffic and road traffic. These model outcomes can subsequently be used to estimate the marginal and total benefits of aircraft noise reduction in the studied area around Amsterdam airport. We find a marginal benefit of 1 dB noise reduction of 1459 Euro per house, leading to a total benefit of 1 dB noise reduction of 574 million Euros.     

Noise Trader Model of Agricultural Product Prices： Evidence from the Chinese Garlic Market

This paper explores the determinants of the abnormal and volatile fluctuations of China＇s agricultural product prices in recent years by examining the trading behavior of traders, especially that of irrational noise traders. We present an overlapping generations model of the garlic market in which noise traders with erroneous beliefs influence prices. Noise traders＇ beliefs create a risk in the price of agricultural products that deters rational arbitrageurs from aggressively betting against them through changing supplies in a way that enables prices to diverge significantly from fundamental values even in the absence of fundamental risk. We also show that asymmetry of supply information, low price elasticity of demand, speculative capital inflows, restricted distribution channels, distorted wholesale markets from the perspective of market mechanisms and low risk aversion, biased self-attribution, and projection bias from the perspective of investor psychology, all influence expectations of investors and increase the volatility of agricultural product prices.     

加性白噪声下基带延迟锁定环跟踪精度的计算

研究了加性白噪声下基带延迟锁定环跟踪精度的计算问题,着重讨论了积分时间和 环路带宽的关系。以码延迟相关鉴别器的等效鉴相模型为基础,研究了相关器输出噪声特性 及其在输入端等效噪声的特性,推导了线性跟踪环输出噪声方差的计算公式,并得到了积分 时间和环路带宽分别起主导作用时的简化计算公式,使两种不同的结论得到了统一。     

基于UC1842的高可靠低纹波多路输出开关电源的设计

依据UC1842的优势,研制了一款高可靠低纹波多路输出开关电源。它将开关电源与三端稳压器件结合,输出具有低纹波的特点,而且可通过极少的元件实现多路隔离输出,因此在军用、医用及通信领域广泛适用。通过实际生产验证,此电源具有可靠性高、纹波低及适用性强的特点。