Benchmark Invariancy,Seasonality and APM-Free Portfolio Performance Measures

The Jobson-Korkie (1981) Z score and the positive period weighting (PPW) score of Grinblatt and Titman (1989) are applied to various benchmarks of market and mimicking portfolios to study the benchmark invariancy problem. Significantly different portfolio performance inferences are found for a sample of 146 equity mutual funds depending on the mean-variance efficiency of the portfolio benchmarks (mimicking portfolios versus market indices). Portfolio performance inferences are affected significantly by the number of factors, nonsynchronous trading adjustment, and the sizes of the firms used for factor extraction. The returns of the portfolio benchmarks exhibit significant monthly seasonalities, which, in turn, significantly influence mutual fund performance inferences.     

Chi-Square Tests Under Models Close to the Normal Distribution

Many test statistics follow a χ² distribution because a normal model is assumed as underlying distribution. In this paper we obtain good analytic approximations for the p-value and the critical value of χ² tests when the underlying distribution is close but different from the normal model. With these approximations we study the robustness of validity of χ² tests     

一种基于均值量化的小波域自同步数字音频水印算法

提出了一种基于均值量化的小波域自同步数字音频水印算法。该算法是一种盲检测算法,检测时不需要原始音频信号。算法引入了系数均值量化的思想,音频信号进行小波分解后,对其中的低频系数进行均值量化,嵌入水印;并且引入了嵌入同步信号的思想,利用同步信号来定位水印的嵌入位置,以抵抗平移、裁剪等攻击。实验结果表明该算法具有较强的鲁棒性和抗攻击性。     

地铁列车初始布点的鲁棒性研究

针对车辆段内干扰源对地铁列车运行的扰动,以列车连带晚点期望值最小为目标,确定地铁列车平峰时段的始发时刻,分配初始缓冲时间。细分连带晚点,详细描述了连带晚点传播的各种情况,建立了简单情形下地铁列车初始布点的理论模型。经分析,该模型为凸规划的约束极值问题,且证明在小干扰条件下,均衡初始布点的列车时刻表为模型的最优解。     

基于微粒群算法的配送中心选址研究

作为挖掘现代企业利润源泉的突破口,配送在物流活动中占有举足轻重的地位。多网点配送中心选址是后续物流活动开展的首要条件,对于该问题的研究具有现实意义。由于微粒群算法的普适性、鲁棒性、全局搜索性等特点,在求解复杂问题中能够较好地体现其优越性。结合运筹学中的运输规划的思想,对复杂的数学模型进行了简化,并针对问题的特点构造了求解编码机制。根据文献资料,将其中的仿真数据进行了整合,使得数据具有一定的现实意义,并用微粒群算法进行求解,得到了较好的效果。     

Robust Likelihood Methods Based on the Skew-t and Related Distributions

The robustness problem is tackled by adopting a parametric class of distributions flexible enough to match the behaviour of the observed data. In a variety of practical cases, one reasonable option is to consider distributions which include parameters to regulate their skewness and kurtosis. As a specific representative of this approach, the skew‐t distribution is explored in more detail and reasons are given to adopt this option as a sensible general‐purpose compromise between robustness and simplicity, both of treatment and of interpretation of the outcome. Some theoretical arguments, outcomes of a few simulation experiments and various wide‐ranging examples with real data are provided in support of the claim.     

About handy, handmade and handsome models

Statistical inference deals with natural variation between units and with uncertainty due to sampling, measurement error and random assignment to treatments. Almost always it does so within one model, assumed fixed and valid. Here, however, variation of conclusions due to variation in model choice will be discussed. Heuristics to find appropriate models are seldom taught, and model fit tests and model fit diagnostics are far from optimal. The use of more than one model for the same data is illustrated by examples from Item Response Theory.     

A Characterization of Robust Sunspot Equilibria

In nonconvex environments, a sunspot equilibrium can sometimes be destroyed by the introduction of new extrinsic information. We provide a simple test for determining whether or not a particular equilibrium survives, or is robust to, all possible refinements of the state space. We use this test to provide a characterization of the set of robust sunspot-equilibrium allocations of a given economy; it is equivalent to the set of equilibrium allocations of the associated lottery economy. Journal of Economic Literature Classification Numbers: D51, D84, E32.     

How Robust Is Indonesia’s Poverty Profile? Adjusting for Differences in Needs

Poverty profiles showing how the magnitude of poverty differs across subgroups of a population are important tools in designing effective social protection programs. Using data from the March 2013 round of the National Socio-economic Survey (Susenas) and the fourth round of the Indonesia Family Life Survey (2007–8), I explore the sensitivity of Indonesia’s poverty profile to different assumptions about the relative costs of individuals, taking into account differences in age, gender, body weight, and physical activity levels. I adopt parameter estimates for my simulation exercises from various Indonesia-specific publications, as well as from a joint intergovernmental consultation on nutrition. I compare my estimates with the per capita scale used by Statistics Indonesia (BPS), the central statistics agency. My findings suggest that the age–poverty relationship in Indonesia is sensitive to assumptions about the relative costs of individuals, with all alternative scales showing substantially lower poverty incidence among young children than by BPS’s estimate. Overall, however, I find that Indonesia’s poverty profile is relatively robust.     

会计稳健性影响因素实证研究

以2009年沪深两市的上市公司数据作为研究样本,在Basu模型的基础上,增加了新的变量,以影响因素的替代变量为解释变量,对影响会计稳健性的因素进行了实证研究。结果表明：会计信息对＂坏消息＂的敏感程度比对＂好消息＂敏感程度更强公司规模与会计稳健性存在负相关关系,市价账面比与会计稳健性存在正相关关系,财务杠杆与会计稳健性的关系与国外研究结果不一致。该研究结果与国外的研究结果基本一致。