从衔接和连贯谈阅读教学

衔接和连贯是语篇中的两个定义,通过分析衔接和连贯在阅读中的作用,提出以语篇为中心进行阅读教学,使学生了解语篇连贯与衔接的最基本知识,从而更准确地掌握主题与作者的意圈。     

Causal relationship between spot and futures prices with multiple time horizons: A nonparametric wavelet Granger causality test

This study investigates the causal information flow between 45 major daily spot returns and their corresponding futures in developing, emerging, and commodity indices through a novel nonparametric wavelet Granger causality test (NWGC) that is capable of detecting causality patterns in various time scales without any stationarity assumption or multivariate autoregressive modeling requirement. We provide new evidence for a complex causality pattern phenomenon. First, there may not be just one dichotomous answer about the Granger causality test for each market data in a time domain, as markets exhibit different causal information flows for different time scales. Second, each market may show distinct causality patterns compared to other markets.     

小波包在Chirp信号检测与时延估计中的应用

在Chirp信号探测中 ,利用发射信号和反射信号之间的时频分布相似性 ,提出用小波包变换时频分布的二维相关算法 ,估计接收信号中各个反射信号分量的时间延迟。该方法具有很强的压制噪声的能力 ,能从 - 5dB的接收信号中很准确地进行Chirp信号检测和时延估计     

主位推进与语篇连贯

连贯是一个复杂的现象,可以从多方面多角度进行研究和分析。其中衔接手段是实现连贯的重要途径之一。而作为语法层面上的结构衔接特征之一的主位推进模式,与语篇连贯联系密切。对其进行研究,能更好探索出句子组合与句子内容之间的关系。     

Comovements between heavily shorted stocks during a market squeeze: Lessons from the GameStop trading frenzy

We examine the comovements between stock prices of different heavily shorted companies during a short-squeeze incident. Using the recent GameStop trading frenzy as a case study, we employ wavelet coherence analyses to determine its link with other frequently shorted stocks. We demonstrate a robust positive association between GameStop prices and the performance of high short interest indices. The bubble behavior driven by retail investor herding transmits between different stocks, even from unrelated sectors. Consequently, a single short-squeeze incident may build up into a potentially broader systemic risk, casting doubt on market integrity and stability.     

Are there profit (returns) in Shariah-compliant exchange traded funds? The multiscale propensity

This paper is the first attempt to investigate the multiscale tendency of the co-movement and cross-correlation of nine Islamic Exchange Traded Fund (ETF) returns across the global developed and emerging markets using both wavelet coherence and wavelet MODWT methods. The wavelet coherence results tend to indicate consistent co-movement between most of the ETF returns especially in the long run. The study also uncovers evidence of wide variation of co-movement across the time-scales during the global financial crisis and the Euro debt crisis. Strong co-movement can be observed during the global financial crisis, both for the medium term investors and long term investors. The paper studies the relationship between different ETF returns using wavelet multi-resolution analysis. The cross-correlation analysis also shows certain significant and positive correlations between the ETF returns, especially during the period of global financial crisis. The findings from these two recent dynamic time-scale decomposition methodologies have important policy implications for both risk management and investors’ investment policy.     

Diversifying equity with cryptocurrencies during COVID-19

Literature suggests assets become more correlated during economic downturns. The COVID-19 crisis provides an unprecedented opportunity to investigate this considerably further. Further, whether cryptocurrencies provide a diversification for equities is still an unsettled issue. We employ several econometric procedures, including wavelet coherence, and neural network analyses to rigorously examine the role of COVID-19 on the paired co-movements of four cryptocurrencies, with seven equity indices (matching countries particularly impacted by COVID-19). Our period of study includes one year prior to the onset of COVID-19, and one year during the pandemic, extending deeper into the pandemic period (February 2021) than most previous studies. We find co-movements between cryptocurrencies and equity indices gradually increased as COVID-19 progressed. However, most of these co-movements are either modestly positively correlated, or minimal, suggesting cryptocurrencies in general do not provide a diversification benefit during either normal times or downturns. An exception, however, is the co-movement of tether. Tether co-moves negatively with equities to an economically significant degree, both pre COVID-19, and considerably more during COVID-19. Co-movements between tether and equity indices spiked sharply during identified waves of the pandemic. Tether appears to be an important safe haven during times of market turmoil, consistent with investors seeking USD liquidity during periods of volatility.     

Technical systems and cross-sector knowledge diffusion: an illustration with drones

If cumulativeness is one feature of knowledge as economic good [Foray, D. 2006. The Economics of Knowledge. Cambridge, MA: The MIT Press], one may wonder why knowledge produced in a given sector does not result in several applications thorough the whole economy. Therefore it is important to understand the dynamics of knowledge that helps a given piece of knowledge to overcome sectorial silos and become more transversal. Here, focusing on Drones, patents analysis reveals how different technical systems use or do not use the same knowledge to solve identical issues or needs. This paper offers three major advantages. First, it allows distinguishing between component knowledge linked with technological bricks and architectural knowledge linked with system integration. Second, it opens new possibilities to measure the transversality of knowledge or its duality (beyond the debates in defense economics). And finally, it offers the opportunity to empirically analyse duality using patent databases.     

我国通胀持久性的区间转换分析及其政策启示

抗通胀是当前一个阶段我国经济面临的重要难题。本文通过非线性小波变换阀值去噪和双区间Markov转移模型的分析表明,无论高通胀区还是低通胀区,我国通货膨胀的持久性均在0.9以上,通胀率偏离预期后受到随机冲击所需的回复时间较长,通货膨胀的治理成本较高。为有效降低我国通胀的高持久性,提高央行货币政策制定的透明度和政策施行的信用度是首要解决的问题。     

运用小波理论提高数据处理的有效性

本文介绍了小波理论用于数据处理方面的一些方法与可能遇到的问题,提出应建立一个适合各种地层构造及储集层的小波基函数库,以提高数据处理的有效性。