从物流设施设备利用率看第三方物流企业的规模问题

本文首次提出了物流设施设备利用率理论。通过比较前后物流设施设备的利用率，把抽象的第三方物流企业规模的条件量化，能够有效地评估某地区需要的第三方物流企业的规模，实现资源优化配置。     

Uniformly most accurate equivariant prediction limit

Summary Prediction limits are widely used for reliability problems and other related problems. The determination of prediction limits has been extensively investigated, but few optimal properties of these limits have been explored. This paper introduces a concept of uniform accuracy in order to compare equivariant prediction limits and show that the prediction limits used for the normal distribution and the exponential distribution are uniformly most accurate equivariant.     

The average number of events per time unit and its estimation

Let ζ _t be the number of events which will be observed in the time interval [0;t] and define limits_{t \to \infty } E$$ " align="middle" border="0"> as the average number of events per time unit if this limit exists. In the case of i.i.d. waiting-times between the events,E[ζ _t ] is the renewal function and it follows from well-known results of renewal theory thatA exists and is equal to 1/τ, if τ>0 is the expectation of the waiting-times. This holds true also when τ = ∞.A may be estimate by ζ _t /t or where is the mean of the firstn waiting-timesX ₁,X ₂, ...,X _n . Both estimators converage with probability 1 to 1/τ if theX _i are i.i.d.; but the expectation of may be infinite for alln and also if it is finite, is in general a positively biased estimator ofA. For a stationary renewal process, ζ _t /t is unbiased for eacht; if theX _i are i.i.d. with densityf(x), then ζ _t /t has this property only iff(x) is of the exponential type and only for this type the numbers of events in consecutive time intervals [0,t], [t, 2t], ... are i.i.d. random variables for arbitraryt > 0.     

涨跌幅受限放开对科创板IPO抑价影响研究

科创板采用上市后前5个交易日不设涨跌幅限制的交易规则,基于2019年7月22至2020年3月31日包括科创板在内的170个新发行股票,研究涨跌幅受限放开对科创板IPO抑价的影响。通过添加涨跌幅受限虚拟变量和交互项建立多元线性回归模型,并通过因子分析法提取代表公司基本面作为控制变量。实证结果表明,相比新股设置首日涨跌幅限制,科创板IPO抑价有了改善,并且在限制首日涨跌幅情况下,首发募集资金净额对IPO抑价负向作用显著。     

浅论紧急避险之必要限度

紧急避险的必要限度在我国刑法典中并没有明确地界定,因而在司法实践中出现了操作上的空白。本文拟比较各国学者有关此问题的不同看法,以探索适合我国国情的解释。     

评述共同犯罪中的实行过限

实行过限行为是共同犯罪行为中的个人行为,需要将实行过限行为从共同犯罪行为中区分开来。所以,实行过限行为的界定、评定标准、构成要件及其处罚以及在实行过限中其他共同犯罪人的处罚是研究的重点内容。     

费尔玛猜想的证明

先证出当j，c，n均为正整数且j＜c，n≥3时。方程cn-（c-j）n-（c-x）n＝0（*）有唯一实根，其中然后证出ti=0．99…9＋0．00…01×p（i），1≤p（i）＜10，i=1，2,…，A式中的s（i）具有如下性质：存在正整数B，使当i＞B时恒有s（i＋2）-s（i＋1）＞s（i＋1）-s（i）≥1，接着又证出，ξ不为整数。最后，对（*）式中的c，c—J，c—x分别令为Z，Y，X，则可由上面的论述得知，当n≥3且Z，Y为相异正整数时，方程Xn＋Yn＝Zn中的X必不为整数。这就证明了费尔玛猜想。     

The Market Quality of Dealer versus Hybrid Markets: The Case of Moderately Liquid Securities

Abstract:  Over the last decade, electronic limit-order trading systems have been sweeping securities exchanges around the world. This paper studies a transitional case, namely, the commencement of trading of a group of moderately liquid stocks on SETS of the London Stock Exchange. The evidence reveals that the liquidity of those stocks dropped substantially after the introduction of the limit order book and the removal of the market makers' obligations. This transition provides an example that a hybrid market with a limit order book and voluntary dealers may not perform as well as a dealership market with obligatory market makers.     

A central limit theorem for the Hellinger loss of Grenander‐type estimators

We consider Grenander‐type estimators for a monotone function , obtained as the slope of a concave (convex) estimate of the primitive of λ. Our main result is a central limit theorem for the Hellinger loss, which applies to estimation of a probability density, a regression function or a failure rate. In the case of density estimation, the limiting variance of the Hellinger loss turns out to be independent of λ.     

Testing the effect of technical analysis on market quality and order book dynamics

We find empirical support for the theoretical finding in agent-based models of limit order book markets that the effect of technical trading on market quality is not positive. When signals occur, technical traders lower liquidity as proxied by the relative spread, the effective spread, the realized spread, the dispersion and the slope in the order book. Technical trading is also found to be accompanied by rising volatility. There is overall strong empirical support against the hypothesis that technical trading has no effect on order book dynamics.