Scoring rules and survey density forecasts

This article provides a practical evaluation of some leading density forecast scoring rules in the context of forecast surveys. We analyse the density forecasts of UK inflation obtained from the Bank of England’s Survey of External Forecasters, considering both the survey average forecasts published in the Bank’s quarterly Inflation Report, and the individual survey responses recently made available to researchers by the Bank. The density forecasts are collected in histogram format, and the ranked probability score (RPS) is shown to have clear advantages over other scoring rules. Missing observations are a feature of forecast surveys, and we introduce an adjustment to the RPS, based on the Yates decomposition, to improve its comparative measurement of forecaster performance in the face of differential non-response. The new measure, denoted RPS*, is recommended to analysts of forecast surveys.     

Disciplinary sanctions in English Premiership Football: Is there a racial dimension?

This paper assesses the evidence for a racial difference in both the dispensation of formal disciplinary sanctions and in the number of fouls called by referees in professional football. The study uses a unique dataset comprising player match-level information drawn from five recent seasons of the English Premiership. These data were merged with data from other sources to identify, among other things, the racial affiliation of the player across four separate categories (viz., white, black, mixed race, and Asian). No systematic evidence of an unfair treatment of players from the non-white minority groups in respect of either the receipt of disciplinary cards or in the number of penalised fouls called by referees was detected.     

基于模糊理论的缺陷检出可靠度模型

分析了缺陷无损检测可靠性的度量问题,通过大量试验数据拟合出缺陷检出率隶属度函数,构建了缺陷检出可靠度的模糊数学模型,最后对飞机机翼大梁螺栓孔退役机件的裂纹长度进行磁粉探测和JFY-1A仪器检测,采用该模型分别计算了两种检测方法在缺陷尺寸临界区间的裂纹检出可靠度,并以金相法检测结果为标准进行对比,验证了模型的有效性。     

双线性有限元Monte Carlo方法

本文构造了矩形有限元的概率算法,应用这种方法可以直接求出有限元解在一个或少数几个网格点的近似值。     

Strategic Bankruptcies and Price Reactions to Bankruptcy Filings

This study investigates whether the stock market differentiates between firms that file bankruptcy petitions for strategic reasons and firms that file bankruptcy petitions for financial reasons. We perform both univariate and regression tests on a sample of 245 firms that filed Chapter 11 bankruptcy petitions between 1981 and 1996. After controlling for bankruptcy outcome, probability of bankruptcy, firm financial condition, and firm size, we find that, in the period around bankruptcy filing, firms that file bankruptcy petitions for financial reasons have significantly larger stock price declines than firms that file bankruptcy petitions for strategic reasons.     

Nonlinear stochastic effects of substitution — an evolutionary approach

Technological innovations have been investigated by means of substitution and diffusion as well as evolution models, each of them dealing with different aspects of the innovation problem. In this paper we follow the well known research traditions on self-organisation models of complex systems. For the first time in the literature we show the existence of a specific niche effect, which may occur in the first stage of establishment of a new technology. Using a stochastic Master equation approach, we obtain analytical expressions for the survival probabilities of a new technology in smaller or larger ensembles. As a main result we demonstrate how a hyperselection situation might be removed in a stochastic picture and thresholds against the prevailing of a new technology in a step-by-step process can be overcome.     

证券投资组合损失率概率评价模型的开发与实证检验

通过建立证券投资组合损失率概率评价模型,定义损失率概率为单个资产或投资组合的损失率超过市场平均损失率的概率,用于对投资组合的风险进行评价。以某基金为例,计算得到该基金的损失率概率为39.74%,表明该基金有39.74%的概率损失率超过市场平均损失率。以证券投资组合损失率概率最小为目标函数,采用遗传算法进行求解,得出该基金投资组合损失率概率最小时的投资权重系数,最小损失率概率为36.01%,与该基金公司的投资组合相比,损失率概率降低了3.73%,实例证明该模型是降低证券投资组合风险的一种实用方法。     

完全市场中的资产定价——有限离散时间情形

研究完全市场中有限离散时间情形下的资产定价问题。首先,给出了无风险收益的概念,借助无风险收益定义了一种风险中性概率。基于这个概率,得到了资产的价格等于随机现金流与随机贴现因子乘积的期望,而且资产的价格还等于资产支付关于q的期望对无风险收益的贴现值。其次,借助无风险概率考虑了资产在多期情形下的资产定价,得出了相应的股票期权公式,尤其作为推论给出了欧式看涨期权的定价公式,并对资产价格过程的鞅性作了讨论。     

我国医疗保健行业股指收益率波动特征与杠杆效应

本文运用SWARCH模型分析了我国医疗保健板块收益率的波动,并将医疗保健板块收益率与上证综指、深证成指收益率的SWARCH模型的估计结果进行比较,得出以下结论:医疗保健指数收益率序列呈现出低、中、高三种波动状态,样本区间主要分布于中波动状态,低波动状态的平均持续期最长、中波动状态的平均持续期居中、高波动状态的平均持续期最短,医疗保健指数收益率波动杠杆效应显著;我国股市医疗保健板块收益率波动状态之间的差异高于沪深综指波动状态的差异,医疗保健指数收益率与沪深综指收益率区制转移趋同,但存在着细微差异;医疗保健指数收益率各区制间转移相对频繁,每种波动状态的平均持续期较短,股市医疗保健板块收益率对新信息的反应更为敏感。     

Exploring the Accuracy of Joint-Distribution Approximations Given Partial Information

Abstract

We test the accuracy of various methods for approximating underspecified joint probability distributions. In particular, we examine the maximum entropy and the analytic center approximations, and we introduce three methods for approximating a discrete joint probability distribution given partial probabilistic information. Our results suggest that recently proposed approximations and our new approximations more accurately represent the possible uncertainty models than do previous models such as maximum entropy.