我国城管执法中存在的问题分析——崔英杰案反映出的行政法问题

崔英杰案中,法院不正确地回避了崔是否有妨害公务罪的问题。从行政法上看,城管定位模糊,不是严格意义上适格的行政主体;执法权限与其他行政主体的权限多有交叉,范围不确定;在执法程序上没有严格遵守法律的明文规定,存在瑕疵。这些问题不仅是个案,而有着深刻的背景。需要制定城管执法的专门法规,对城管的主体身份和权限做出明确规定,使之严格依照法定程序行使权力。     

Detection of outliers in growth curve models

The growth curve model introduced by Potthoff and Roy (1964) is a general statistical model which includes as special cases regression models and both univariate and multivariate analysis of variance models. In this paper, we discuss procedures for detection of outliers in growth curve models for mean-slippage and dispersion-slippage outlier model. The distributions of the test statistics are discussed and the values of significant probabilities are given using Bonferronl's bounds. Some simulation results are also presented.     

Minimum variance unbiased invariant estimation of variance components under normality

In a variance components model for normally distributed data, for a specified vector of linear combinations of the variance components, necessary and sufficient conditions are given under which the vector has a uniformly minimum variance unbiased translation-invariant estimator. The competing class of estimators is not restricted to those that are quadratic. For classification models, the conditions are translated into easy-to-check partial balance requirements on the incidence array.     

Ruin Probabilities for the Perturbed Compound Poisson Risk Process with Investment

In this article, we consider the perturbed compound Poisson risk process with investment incomes. The risk reserve process is perturbed by an independent Brownian motion and the surplus is invested at a constant force of interest. We investigate the asymptotic behavior of the ruin probability as the initial reserve goes to infinity. Bounds and time-dependent bounds are derived for the ultimate ruin probability and the probabilities of ruin within finite time, respectively. We also obtain an explicit expression for the Laplace transform of the ultimate ruin probability.     

分时电价下关注能耗成本的生产问题建模及算法

随着环境保护及能源危机问题的日益突出,如何均衡用电负荷、适应能源供给侧结构特点,从而减小企业运营成本以提高自身盈利能力,已经成为能源敏感型企业在当前时代亟待解决的实际问题。本文以单机生产系统为研究对象,建立了分时电价模式下能耗成本最小化问题的连续时间混合整数规划模型。首先,针对工件顺序固定时的子问题,考虑到非线性因素的影响,证明了最优缓冲时间长度与电价调整时刻的一致性关系,据此设计了分枝定界算法中的分枝规则,并通过开发快速的低界求解方法及有效的剪枝策略,保证了算法可在短时间内求得精确解。继而,通过随机排序、ERD排序、邻域搜索排序、遗传算法排序等不同方法的比较,分析了工件顺序对问题最终总成本的影响程度。同时,在不同参数组合的数据实验中,将本方案与传统生产调度方案进行对比,表明了本文模型在节约能耗成本方面的巨大优势。最后,本文所设计算法解决了周期差异引起的非线性的难题,可以此为子模块求解更加复杂的扩展问题,比如考虑可再生能源生产周期的企业内多种能源实时分配问题。     

A best first search exact algorithm for the Multiple-choice Multidimensional Knapsack Problem

In this paper, we propose an optimal algorithm for the Multiple-choice Multidimensional Knapsack Problem MMKP. The main principle of the approach is twofold: (i) to generate an initial feasible solution as a starting lower bound, and (ii) at different levels of the search tree to determine an intermediate upper bound obtained by solving an auxiliary problem called MMKP_aux and perform the strategy of fixing items during the exploration. The approach which we develop is of best-first search strategy. The method was able to optimally solve the MMKP. The performance of the exact algorithm is evaluated on a set of small and medium instances, some of them are extracted from the literature and others are randomly generated. This algorithm is parallelizable and it is one of its important feature.     

Berry-Esseen bounds for kernel estimates of stationaryprocesses

In this paper we obtain nonuniform Berry-Esseen bounds of the kernel estimate of stationary process {X_i} by the method of martingale approximation. In particular, by choice of bandwidth b_n, the Berry-Esseen bounds can be n^−2/15. The dependence condition of {X_i} is expressed in terms of physical dependence measures introduced by Wu (2005).     

Sampling and empirical risk minimization

ABSTRACT

In certain situations that shall be undoubtedly more and more common in the Big Data era, the datasets available are so massive that computing statistics over the full samples is hardly feasible, if not unfeasible. A natural approach in this context consists in using survey schemes and substituting the ‘full data’ statistics with their counterparts based on the resulting random samples, of manageable size. It is the main purpose of this paper to investigate the impact of survey sampling on statistical learning methods based on empirical risk minimization through the standard binary classification problem, considered here as a ‘case in point’. Precisely, we prove that, in presence of auxiliary information, appropriate use of optimally coupled Poisson survey plans may not affect much the learning rates, while possibly reducing significantly the number of terms that must be averaged to compute the empirical risk functional with overwhelming probability. These striking results are next shown to extend to more general sampling schemes by means of a coupling technique, originally introduced by Hajek [Asymptotic theory of rejective sampling with varying probabilities from a finite population. Ann Math Stat. 1964;35(4):1491–1523].     

Sharp Threshold Detection Based on Sup-Norm Error Rates in High-Dimensional Models

We propose a new estimator, the thresholded scaled Lasso, in high-dimensional threshold regressions. First, we establish an upper bound on the ?_∞ estimation error of the scaled Lasso estimator of Lee, Seo, and Shin. This is a nontrivial task as the literature on high-dimensional models has focused almost exclusively on ?₁ and ?₂ estimation errors. We show that this sup-norm bound can be used to distinguish between zero and nonzero coefficients at a much finer scale than would have been possible using classical oracle inequalities. Thus, our sup-norm bound is tailored to consistent variable selection via thresholding. Our simulations show that thresholding the scaled Lasso yields substantial improvements in terms of variable selection. Finally, we use our estimator to shed further empirical light on the long-running debate on the relationship between the level of debt (public and private) and GDP growth. Supplementary materials for this article are available online.     

深化我国农地制度改革的建议

当前我国农地产权政策选择的关键是实现公平和效率的兼顾,这是达到社会效益最大化的制度保证。为此,农地产权制度改革必须解决好以下几个问题:一是进一步明晰农地使用权的产权界定,建立以村为基础、乡统筹的农地产权制度,强化和稳定农户的土地承包关系;二是建立有效的土地流转机制,提高农地配置效率;三是构建新的农地法律制度框架。