Forecasting value at risk and expected shortfall with mixed data sampling

I propose applying the Mixed Data Sampling (MIDAS) framework to forecast Value at Risk (VaR) and Expected shortfall (ES). The new methods exploit the serial dependence on short-horizon returns to directly forecast the tail dynamics of the desired horizon. I perform a comprehensive comparison of out-of-sample VaR and ES forecasts with established models for a wide range of financial assets and backtests. The MIDAS-based models significantly outperform traditional GARCH-based forecasts and alternative conditional quantile specifications, especially in terms of multi-day forecast horizons. My analysis advocates models that feature asymmetric conditional quantiles and the use of the Asymmetric Laplace density to jointly estimate VaR and ES.     

Mixed-frequency approaches to nowcasting GDP: An application to Japan

In this paper, we discuss the approaches to nowcasting Japan’s GDP quarterly growth rates, comparing a variety of mixed frequency approaches including a bridge equation approach, Mixed-Data Sampling (MIDAS) and factor-augmented version of these approaches. In doing so, we examine the usefulness of a novel sparse principal component analysis (SPCA) approach in extracting factors from the dataset. We also discuss the usefulness of forecast combination, considering various ways to combine forecasts from models and surveys. Our findings are summarized as follows. First, some of the mixed frequency models discussed in this paper record out-of-sample performance superior to a naïve constant growth model. Second, albeit small, the SPCA approach of extracting factors improves predictive power compared with traditional principal component approach. Furthermore, we find that there is a gain from combining model forecasts and professional survey forecasts.     

基于Gibbs采样的MIMO信号检测改进算法

针对传统Gibbs采样算法的“失控问题”,提出了一种改进算法,在Gibbs迭代采样过程中加入对噪声方差的估计,消除了失控问题。设计了信号检测流程,将最大似然（ML）检测的搜索过程嵌入Gibbs迭代采样过程,减少了最大似然检测的计算步骤。仿真结果表明,所提算法能估计噪声方差,具有接近最大似然检测的性能。     

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.     

统计理论在木片抽样方案中的应用

介绍了木片取样的系统抽样方案,经验抽样方案和概率抽样方案,通过分析系统取样方案中含水率、规格片、朽木和树皮等检验项目的历史统计,提出含水率,规格片和树皮都服从近似正态分布的规律,并在此基础上预设了含水率的允差。     

Product Patent Reform and its Impact on Korea's Pharmaceutical Industry

Our analysis focuses on the effect of U.S. government pressure on Korea to adopt product patents for chemical and pharmaceutical products. American pressure began in November 1985 and ended with the Korean Legislature's passage of a new patent law in December 1986. We conduct an event study of the effect of the new patent law on the value of Korean pharmaceutical firms listed on the Korea Stock Exchange. Regression analysis shows that the new law induced excess returns of-74 percent over the 14-month analysis period. The results suggest that adoption of stronger patent laws reduced Korea's wealth. [G14, O34]     

中频接收机数字化设计中的几个关键问题

本文以短波数字化中频接收机为例，讨论中频数字化接收机设计的几个关键问题，包括收机前端增益的确定、数字和模拟AGC门限的选取、二中频频率与取样率的选择、以及接收机信噪比（SNR）的核算。     

Measuring the cost of liquidity in agricultural futures markets: Conventional and Bayesian approaches

Estimating the cost of liquidity in agricultural futures markets is challenging because bid‐ask spreads are usually not observed. Based on an ability to reflect simulated data from Roll's spread model, we assess the effectiveness of conventional and Bayesian bid‐ask spread estimators under different market conditions. Conventional serial covariance and absolute price change spread estimators appear to be biased. Hasbrouck's Bayesian estimator generates small costs of liquidity whose values depend on the correlation and noise in the data. The absolute value Bayesian estimator is precise and works well under conditions of high levels of noise and correlation usually found in agricultural futures markets. Using data from live cattle (LC) and lean hog (LH) contracts, we find similar patterns of performance that produce economically meaningful cost of liquidity differences.     

通胀率动态与通胀惯性度量

本文从通胀惯性的理论模型出发,构建无限状态Markov区制转移的计量模型,实现对通胀惯性的有效度量。对美国通胀惯性的实证分析,证实货币政策工具的频繁使用会付出通胀惯性的代价,暴露出其单一目标货币政策框架的缺陷。我国央行的调控也已经对市场利率形成了显著的传导作用,谨慎地使用货币政策工具,使我国的通胀惯性在被货币政策短暂影响后,得以有效恢复。这表明坚持实行多目标、多手段与宏观审慎政策相结合的调控模式,对维护经济环境稳定与长期发展的重要性。十国通胀惯性的度量结果与对比分析,进一步佐证了本文观点。     

样品扦样与制备-真菌毒素准确分析中的决定性因素

本文介绍了真菌毒素污染水平检测过程中,影响其准确分析和正确评价的两大决定性因素——样品扦样和样品制备。指出样品扦样作为真菌毒素检测的第一步,直接关系到结果的代表性和可靠性,是引起真菌毒素检测结果变异程度的最大原因;样品制备,与分析结果直接相关,是真菌毒素准确分析、正确评价的重要保障。对这两方面应该给予足够重视,加强有关规范和标准的制定。