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排序方式: 共有407条查询结果,搜索用时 16 毫秒
1.
This paper focuses on an unexplored dimension of fund managers’ timing ability: Market-wide tail risk implied by information in options markets. Constructing the option-implied tail risk, we investigate whether hedge fund managers can strategically time the tail risk through adjusting their exposure to changes of it. Using an extensive sample of equity-oriented hedge funds, we find strong evidence of tail risk timing ability of hedge fund managers. Furthermore, tail risk timing ability brings significant economic value to investors. Top-ranked funds outperform bottom-ranked funds by 5–7% annually after adjusting for risk factors. Our results are robust to various robustness checks.  相似文献   
2.
In recent years, labor-intensive agricultural products from developing countries have exhibited inferior performance in international trade due to quality and safety incidents, among which pesticide residue is a major issue. Aiming to improve food quality and safety in the context of cooperatives, we introduced three categories of control measures: outcome control, process control and social control. Based on the Pre-Harvest Interval Standard (PHIS), we selected three indices, farmers’ implementation rate of PHIS, absolute distance to PHIS and relative distance to PHIS, to evaluate appropriateness of pesticides use, reduction of pesticide residue and safety improvements of agricultural products. By using random sampling survey data, we empirically analyzed the marginal effects of control measures and their combinations on food quality and safety standards. The empirical results show that implementing process control, namely, unified production standards or supply of unified agricultural inputs, can comprehensively improve farmers’ implementation rate of PHIS, absolute distance and relative distance to PHIS respectively by 34.9%, 3.2 days and 46.0% on average. While the effects of outcome control (safety inspection) and social control (bonus-penalty incentive or training) are restricted to other measures. Therefore, we suggest cooperatives should take farmers’ features, implementation conditions and the effects of control measures into consideration in order to make a sustainable management plan for improving food quality and safety and enhancing competitiveness in international markets.  相似文献   
3.
We document a negative impact of realistic trading timing on trend-following profits, across an international sample of equity indexes and stocks. The discount effect is substantial but reduces as trend signals become less accurate. The size of this trading timing bias is largely driven by the volatility of buy-and-hold returns and that of trend signals.  相似文献   
4.
Theory predicts that market‐timing activities bias Jensen's alpha (JA). However, empirical studies have failed to find consistent evidence of this bias. We tackle this puzzle in a nested model analysis and show that the bias contains an exogenous market component that is unrelated to market‐timing skill. In a comprehensive empirical analysis of US mutual funds, we find that the timing‐induced bias in JA is mainly driven by this market component, which is uncorrelated with measured timing activities. Measures of total performance that allow for timing activities are virtually identical to JA, even if timing activities are present in the evaluated fund. Hence, we conclude that JA is a sufficient measure of total performance.  相似文献   
5.
This study examines how market timing can affect host market reaction to cross-border seasoned equity offerings (SEOs), an event generally viewed unfavorably by investors. We assume that firms engage in market timing in response to valuation uncertainty (VU), home market uncertainty (HMU) and/or host market uncertainty (HSU), and that raising capital abroad faces higher scrutiny costs and familiarity bias from host market investors. We conjecture that timing strategies provide signals that vary in strength to host market investors and that dual-timing strategies may strengthen an existing signal. Our hypotheses are tested on a sample of 190 cross-border SEOs that were issued on the U.S. stock market between 1990 and 2017 by firms from 29 countries. Using event study methodology, we find that market timing based on VU is negatively related to host market valuation and that a dual-timing strategy with HMU or HSU generally produces a stronger signal. Our results have practical relevance for stock markets that suffer from high uncertainty; we estimate that a high VU firm with a $1 billion valuation suffers a drop of $31.3 million in market valuation during a high host market uncertainty (high HSU) compared with low host market uncertainty (low HSU).  相似文献   
6.
徐明杰  韩印 《物流科技》2020,(1):106-110
为了合理地优化交叉口信号配时,通过分析交叉口的评价指标,建立了以车辆的平均延误、停车次数最小、交叉口整体通行能力最大、各相位有效绿灯时间和交叉口周期时长作为约束条件的数学模型。并通过改进前人研究基础上的动态加权系数,将多目标的非线性优化问题转化为单一目标的非线性规划问题,为了得出更科学稳定的解,提出了改善粒子群算法系统稳定性的2种方法,并将其与粒子群算法结合起来。然后以Matlab为求解工具,结合临邑市某一交叉口实例进行求解分析。最后的结果表明,在使用改进后的粒子群算法进行优化后交叉口通行能力较之现状提升了9%,延误下降了28%,停车次数下降了9%,且各项优化结果均优于Webster,改进后的算法在程序中运行300代,到216代才开始收敛,而未改进的算法稳定性较差,优化结果和收敛曲线则随着实验次数的变化而变化,最后的结论证明了该算法和模型的可靠性。  相似文献   
7.
森林资源丰富与贫困聚集并存,且"均山"改革下的林地细碎化又降低了资源利用效率,而通过林地流转实现贫困缓解却存在树种依赖。本文利用2015年中国农村林业改革发展监测数据,在分树种测算农户生产效率的基础上,将林地流转引发的效率变化对农户经营收入影响产生的绝对减贫效应和相对减贫效应进行检验。结果表明,农户林地生产效率较低且不同农户间的效率差异明显;经营杉木与松木的农户通过林地流转能够实现绝对贫困与相对贫困的缓解,但对经营果树而言,生产效率更高的农户从林地流转中获益更多,形成相对剥夺,农户间相对贫困加剧;毛竹经营不存在规模依赖,林地流转也不存在减贫效应。林地流转的政策鼓励需要考虑利益导向,同时关注村庄内部的不平等。  相似文献   
8.
We comprehensively analyze the predictive power of several option-implied variables for monthly S&P 500 excess returns and realized variance. The correlation risk premium (CRP) and the variance risk premium (VRP) emerge as strong predictors of both excess returns and realized variance. This is true both in- and out-of-sample. Our results also reveal that statistical evidence of predictability does not necessarily lead to economic gains. However, a timing strategy based on the CRP leads to utility gains of more than 5.03% per annum. Forecast combinations provide stable forecasts for both excess returns and realized variance, and add economic value.  相似文献   
9.
LTE(Long Term Evolution)系统中,作为小区搜索的第一步,符号定时算法需要具备很强的鲁棒性。为了进一步增强现有符号同步算法的抗频偏性能,提出了一种优化的符号同步算法。该算法一方面保持已有分段相关同步算法的优点,同时考虑结合预频偏处理来进行符号定时与粗频偏的联合估计,再将多个相关运算集做叠加处理。理论分析和仿真实验结果表明,在多径信道下,所提算法在完成符号定时和粗频偏估计的同时,大大提高了系统抗频偏性能。  相似文献   
10.
多输入多输出正交频分复用(MIMO-OFDM)系统对定时偏移和频率偏差极其敏感,并且对时间同步精度要求极高。分析比较了29种具有代表性的MIMO-OFDM系统同步算法的优缺点,指出针对数据辅助类的同步方法,采用共轭、取反等特性构造优良正交性的训练序列是提高时间同步性能的关键,可在时域进行频偏估计和降低参数维数来降低系统计算复杂度;针对非数据辅助类的同步方法,构造计算复杂度较低的代价函数是提高频率同步性能的关键,这些都是MIMO-OFDM系统同步方法值得研究的方向。  相似文献   
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