Does higher government debt link to higher social expenditure? New method,new evidence

Scholars believe that higher social expenditures are usually linked with higher government debts, whereas higher debts reduce social expenditures. However, it is reasonable to speculate that higher government debt may contribute to higher social spending, while fiscal deficits occur during a recession, which commonly creates greater demand for social expenditure. For a deeper investigation, this paper revisits the dynamic relationship between social spending and public debts in the time-frequency domain, using the novel wavelet-coherency analysis as well as the phase-difference technique to derive the co-moved and causal relationships between social spending and public debts in 13 OECD countries. The evidence identifies a dynamic relationship between variables. While higher social expenditures increase government debts, the shocks from government debts to social expenditures are conversely uncertain. We discover that higher government debt does reduce social expenditures, but it may be linked to higher social spending. The robustness of partial coherency and phase-difference discovers the role of a political party in the decision over social welfare programmes in the sample countries.     

一种改进的CPFSK信号频率估计方法

针对突发信号解调中多普勒频偏大的问题，提出了一种改进的连续相位移频键控信号(CPFSK)频率估计方法。首先接收信号平方运算使信号的调制指数加倍，再通过一次离散傅里叶变换(DFT)，用搜索信号平方谱谱峰的方法实现突发信号频率估计。仿真实验表明，在低信噪比条件下，该算法的频率估计精度比经典的相位差频率估计算法提高了20%；该算法与广泛用于高动态突发信号的频率插值估计算法相比，同道干扰信道下信干比改善可达4 dB，DFT长度缩短约1/3。     

Time-frequency co-movements between oil prices and interest rates: Evidence from a wavelet-based approach

This paper investigates time–frequency co-movements between crude oil prices and interest rates. To test this relationship, the study applied a continuous wavelet and cross wavelet approaches to data from West Texas Intermediate (WTI) crude oil prices and interest rates in the United States (U.S.). Results from the sample period revealed significant relationships, in the intermediate term, between WTI crude oil prices and U.S. interest rates. Moreover, co-movements between oil price and interest rate variables were especially sensitive during abnormal political events and periods of financial ‘meltdown’. We further use Partial Wavelet Coherence (PWC) and Multiple Wavelet Coherence (MWC) methods to investigate the impacts of five major control variables namely GDP growth, unemployment, three-month Treasury bill, CPI index and industrial production index. The results show a powerful impact of control variables on oil-interest rates co-movements under different frequencies. Finally, we show evidence of co-integrating long run relationship between oil markets and control variables. These results have important implications for energy investors and policy makers.     

STOCK‐BOND CO‐MOVEMENTS AND FLIGHT‐TO‐QUALITY IN G7 COUNTRIES: A TIME‐FREQUENCY ANALYSIS

This paper examines co‐movement between stock returns and changes in 10‐year government bond yields as well as flight‐to‐quality behaviour in G7 countries. We conduct the wavelet squared coherence analysis to explore the dynamics in both time and frequency domain. Our results provide evidence of positive co‐movements, which vary over time and across investment horizon. The higher co‐movement is found to be more concentrated in the lower frequency bands. We further analyse the dynamic nature of the scale‐dependent wavelet correlations and find that the correlations are highly volatile and significantly increase across different time scales during the episodes of equity market turbulence. The increase in correlations reflects flights from stocks to safer bond investments as a result of dramatic changes in investor sentiment and risk aversion at times of market stress.     

基于小波变换的图像处理综述

小波分析主要广泛应用在科学研究和工程技术中。虽然在现阶段的小波理论相对成熟,近些年关于小波理论的应用和研究也在不断的发展和更新。小波变化在图像处理领域中的应用也囊括图像与处理的所有方面。本文通过介绍小波变换的起源,将小波应用在图像处理中的压缩、还原图像、边缘检测和图像分割,宏观剖析小波的研究现状历史、发展动向及优势。     

Valuation of forward start options under affine jump-diffusion models

Under the general affine jump-diffusion framework of Duffie et al. [Econometrica, 2000, 68, 1343–1376], this paper proposes an alternative pricing methodology for European-style forward start options that does not require any parallel optimization routine to ensure square integrability. Therefore, the proposed methodology is shown to possess a better accuracy–efficiency trade-off than the usual and more general approach initiated by Hong [Forward Smile and Derivative Pricing. Working paper, UBS, 2004] that is based on the knowledge of the forward characteristic function. Explicit pricing solutions are also offered under the nested jump-diffusion setting proposed by Bakshi et al. [J. Finance, 1997, 52, 2003–2049], which accommodates stochastic volatility and stochastic interest rates, and different integration schemes are numerically tested.     

小波域抑制多音干扰的扩频接收机

利用小波包理论提出了一种快速、准确地识别并且抑制多音干扰的有效方法。该方法利用小波包理论将多音干扰的各条谱线逐个定位，然后通过功率谱分析的方法来识别多音干扰的存在区间，最后将被干扰污染的区间逐个切除并反向重构接收到的信号。实验证明该方法的误比特率性能在强干扰时要优于以前的FFT域切割法。     

汽车倾斜牌照中字符的定位与提取

提出了汽车图像中倾斜汽车牌照字符的定位与提取算法。该算法针对汽车牌照的灰度特点,先确定牌照的位置,并从背景中分割出来。对二值化车牌定位图通过Hough变换,计算出车牌主要直线的倾斜角度,通过插值旋转后,重新确定车牌字符的边界,最后精确地提取出汽车牌照中的字符。与其它传统的方法比较,该方法在运算速度和精确性上有一定优势。     

加快发展物流业是转变经济发展方式的战略重点

加快发展物流业是转变经济发展方式的战略重点.目前物流业发展明显滞后,专业化、社会化程度低,物流要素配置缺乏统筹协调,缺少实力强大的跨国企业.“十二五”时期物流业发展面临新的机遇:我国基础设施建设快速推进,国内统一的大市场形成,融入全球化步伐加快,多种所有制、多种运输方式互相竞争的格局形成,为现代物流业发展奠定了基础.当前,要以贯彻落实《国务院办公厅关于促进物流业健康发展政策措施的意见》为契机,加快现代物流业发展.加强体制机制创新,积极进行全球布局,“走出去”到海外谋发展.同时要加快培养现代物流业管理人才,努力培养一批世界一流的物流企业家,发展世界一流的物流企业.     

高压输电线路故障测距算法综述

高压输电线路故障定位的准确性对电网的稳定运行有着非常重要的意义。文章对高压输电线路现有的各种测距方法进行了归纳总结和研究分析,并评述了各自的优点和不足。