SEM图像分形维数的影响因素研究

以玻璃光纤、碳纤维纸和两种机加工表面样本的扫描电子显微镜图像为对象,运用盒维法研究了不同的放大倍数和采集过程中受到的噪声干扰对分形维数的影响.研究结果表明,随着放大倍数增大或随着椒盐噪声密度和高斯随机噪声方差的减小,分形维数下降.放大倍数和噪声对分形维数都有较大影响.在扫描电子显微镜图像分形维数的计算中,可以依据试样的结构特征选择合适的放大倍数,进行去噪处理后再计算图像的分形维数.     

S-CDMA技术在HFC网络上行信道中的分析应用

在基于CATV的HFC双向网络中,S-CDMA的同步处理技术可以最大限度地克服上行信道中的噪声干扰,提高信道的利用率,确保数据传输的可靠性。     

The Announcement Effect of an Airport Expansion on Housing Prices

The purpose of this study is to examine the influence of the announcement of a new airport hub on housing prices near the airport. While numerous studies of airport noise have found that high noise levels reduce property values, few have been able to measure the announcement effect on values. The results indicate that after controlling to extraneous influences, housing property prices in a 2.5 mile band from the Greensboro/High Point/Winston Salem metropolitan airport declined approximately 9.2% in the post-announcement period. In the next 1.5-mile band, house prices declined approximately 5.7% in the post-announcement period.     

榆林市某羊场舍饲陕北白绒山羊羔羊死亡原因研究

本文旨在研究榆林市某羊场舍饲陕北白绒山羊羔羊的死亡情况及死亡原因,为治疗和预防羊场疾病提供理论依据。本文主要采用实地考察和访谈方式,了解羊场的饲喂、管理、配种以及产羔情况,并对羊场的消毒防疫、发病症状、病理变化和羔羊死亡数量做了详细记录。经统计分析得出羔羊死亡主要原因:繁殖障碍,哺乳失常,管理不当,肺炎和痢疾等。其中肺炎占死亡总数的13.9%,痢疾占死亡总数的68.7%,繁殖障碍死亡占死亡总数的5.2%;哺乳不当弱胎饥饿占死亡总数的7.8%;管理不善及其他原因占死亡总数的3.5%。主要防治措施:以预防为主,治疗为辅,标本兼治,加强饲养管理,全群注射三联四防苗,使羔羊死亡情况得以控制。     

A Tutorial on Palm Distributions for Spatial Point Processes

This tutorial provides an introduction to Palm distributions for spatial point processes. Initially, in the context of finite point processes, we give an explicit definition of Palm distributions in terms of their density functions. Then we review Palm distributions in the general case. Finally, we discuss some examples of Palm distributions for specific models and some applications.     

Social media bots and stock markets

This study examines the link between information spread by social media bots and stock trading. Based on a large sample of tweets mentioning 55 companies in the FTSE 100 composites, we find significant relations between bot tweets and stock returns, volatility, and trading volume at both daily and intraday levels. These results are also confirmed by an event study of stock response following abnormal increases in the volume of tweets. The findings are robust to various specifications, including controlling for traditional news channel, alternative measures of volatility, information flows in pretrading hours, and different measures of sentiment.     

Comparison of public perception and risk management decisions of aircraft noise near Taoyuan and Kaohsiung International Airports

This study uses multiple linear regression to identify factors contributing to perceived risk among residents near Taoyuan and Kaohsiung International Airports, the effect of perceived risk on their willingness to reduce risk, and consumption preferences that can reduce risk. Results indicated that residents' risk perception near Taoyuan Airport is lower than that near Kaohsiung Airport. Noise pollution experience, perceived probability of environmental contamination and negative effects, and perceived severity of catastrophic consequences significantly increase residents' perceived risks. Residents are willing to recognize and participate in mitigating the risks of aircraft noise pollution. The more risk residents perceive, the more willing they are to participate in disaster reduction and investigate means of improving the risk environment.     

Determining the integrated volatility via limit order books with multiple records

The integrated volatility plays an important role in risk management and portfolio selection, the estimation methods regarding the quantity have been widely investigated, either under low-frequency data or high-frequency data, or a combination of both. In this paper, we propose a measure for the integrated volatility via limit order book data with possible presence of multiple records. The estimator is valid under mild conditions and it is easily implemented. The finite sample performance of the proposed estimator has been verified by simulation studies and we apply the method to some real high-frequency data-sets as well.     

Assessment of land use compatibility and noise pollution at Imam Khomeini International Airport

This study aimed to investigate land use planning around airports, by employing Remote Sensing (RS) and Geographic Information Systems (GIS), in conjunction with an optimization algorithm using an Integrated Noise Model (INM) software, to establish the potential effects of aircraft noise at Imam Khomeini International Airport (IKIA) in Tehran. We also checked for land use compatibility with the noise levels around IKIA and the residents' reaction to the noise. The research was carried out in three stages: a) the establishment of Strategic Noise Map (SNM) scenarios of the airport operation in the years 2011, 2020 and 2030 using the INM software; b) the assessment of the results with emphasis on the study area land uses and application of RS and GIS and the exposure of residents at different levels of environmental noise; and c) the assessment of the intensity of aircraft noise annoyance at various times of day and night. The results indicated that developing IKIA together with the residential development will increase airport noise. Hence proper management and control of noise at IKIA is essential.     

透过亚当斯领略黑白摄影的魅力

在漫长的黑白摄影发展的进程中,摄影大师安塞尔·亚当斯做出了卓越的贡献,尤其是"f64小组"和完善的区域曝光系统成为摄影史上的里程碑。黑、白、灰黑白摄影演绎着影调与影像的经典,即使在现代彩色摄影高度发展的今天,黑白摄影并没有失去它往日的光彩,也不会被彩色摄影所更替,它将以独特的魅力,以单纯、洗练、视觉冲击力强等审美优势继续发展,创造更多视觉财富。