Conditional covariance penalties for mixed models

The prediction error for mixed models can have a conditional or a marginal perspective depending on the research focus. We introduce a novel conditional version of the optimism theorem for mixed models linking the conditional prediction error to covariance penalties for mixed models. Different possibilities for estimating these conditional covariance penalties are introduced. These are bootstrap methods, cross-validation, and a direct approach called Steinian. The behavior of the different estimation techniques is assessed in a simulation study for the binomial-, the t-, and the gamma distribution and for different kinds of prediction error. Furthermore, the impact of the estimation techniques on the prediction error is discussed based on an application to undernutrition in Zambia.     

逆向选择条件下带奖惩金的两期保险契约模型及其Pareto改进性研究

为了更有效的规避影响保险市场交易效率的逆向选择问题，本文分投保人风险类型为两种和多种情形建立了带奖惩金的两期保险契约模型，首次提出可以用奖励金和惩罚金有效甄别投保人的风险类型。该模型根据投保人第一个保险期内的索赔情况在第二个保险期对其进行奖励或惩罚，高风险类型的投保人如果选择为低风险类型投保人设计的保险契约，则其在第二阶段受到惩罚的概率要远远大于得到奖励的概率，即风险越高的投保人越害怕惩罚金，因此所建模型满足斯彭斯-莫里斯分离条件。带奖惩金的两期保险契约模型中保险公司的期望利润仍然为0，并不会给投保人带来额外的经济负担，却能够实现对传统部分保险契约简单重复两次的严格帕累托改进。最后采用一个算例说明了该模型的有效性。     

A Necessary Condition for the Strong Oracle Property

A problem of using a non‐convex penalty for sparse regression is that there are multiple local minima of the penalized sum of squared residuals, and it is not known which one is a good estimator. The aim of this paper is to give a guide to design a non‐convex penalty that has the strong oracle property. Here, the strong oracle property means that the oracle estimator is the unique local minimum of the objective function. We summarize three definitions of the oracle property – the global, weak and strong oracle properties. Then, we give sufficient conditions for the weak oracle property, which means that the oracle estimator becomes a local minimum. We give an example of non‐convex penalties that possess the weak oracle property but not the strong oracle property. Finally, we give a necessary condition for the strong oracle property.     

具有超前或延误损失的单机排序问题

在变换条件下对于JIT准时生产制排序问题中的一种特殊情况──排序问题中只含超前损失和延误损失，得到最优序列的一些条件。     

俄罗斯刑事执行法典的发展变革及对我国的启示

俄罗斯现行刑事执行法典源于沙俄监狱规范与苏维埃劳动改造法典,该法典借鉴二者基本框架与内容构设了俄罗斯现行刑事执行立法体系,对刑事执行法律的各项基本原则做了较为明确的规定,较好地反映了俄罗斯当代刑事执行政策的立法导向,对刑罚执行人道化、刑罚执行差别对待与个别处理等价值目标贯彻得比较彻底,既有利于被处刑人员的矫正,也有利于其释放后回归社会。该法典对我国刑事执行立法法典化及刑事执行政策的推行与贯彻具有重要的启示意义。     

对《苏州市湿地保护条例》的评析及完善建议

《苏州市湿地保护条例》在借鉴我国已有的湿地保护法规、立法经验的基础上,建立了湿地保护专家委员会;根据所在行政区域湿地的地域性特点,将永久性水稻田纳入湿地保护的范围;总结行之有效的实践经验,确定了湿地生态补偿机制。但从内容上看,它没能彻底解决我国湿地行政管理体制与湿地保护问题综合性之冲突及湿地保护违法成本低的难题。建议设立苏州市湿地保护协调委员会,并将湿地违法行为的处罚额度与苏州市经济水平相结合。     

无刑事责任能力精神病人的司法处遇

根据人道主义和刑事责任理论,犯罪的精神病人如果无刑事责任能力,不负刑事责任,不受刑事处罚。但是,精神病人犯罪有精神障碍方面的原因,如果不对其加以必要的治疗,消除或者控制他们犯罪的病理原因,他们有可能继续犯罪。因此,从社会防卫等角度出发,应当对有严重危险性的精神病人实施强制治疗。     

A Thresholding Algorithm for Order Selection in Finite Mixture Models

Order selection is an important step in the application of finite mixture models. Classical methods such as AIC and BIC discourage complex models with a penalty directly proportional to the number of mixing components. In contrast, Chen and Khalili propose to link the penalty to two types of overfitting. In particular, they introduce a regularization penalty to merge similar subpopulations in a mixture model, where the shrinkage idea of regularized regression is seamlessly employed. However, the new method requires an effective and efficient algorithm. When the popular expectation-maximization (EM)-algorithm is used, we need to maximize a nonsmooth and nonconcave objective function in the M-step, which is computationally challenging. In this article, we show that such an objective function can be transformed into a sum of univariate auxiliary functions. We then design an iterative thresholding descent algorithm (ITD) to efficiently solve the associated optimization problem. Unlike many existing numerical approaches, the new algorithm leads to sparse solutions and thereby avoids undesirable ad hoc steps. We establish the convergence of the ITD and further assess its empirical performance using both simulations and real data examples.     

刑事责任的概念和本质探究

刑事责任是犯罪的法律后果,是刑罚适用的前提和基础。弄清刑事责任的概念和本质,不仅有助于我们进一步加深对刑事责任的理性认识,而且有助于我们从各个不同的角度认识行为人何故就自己的犯罪行为负刑事责任。     

小微企业食品安全问题、特征、原因和对策

通过对2011-2015年间我国364件小微企业食品安全事故的研究,指出小微企业食品安全的问题,系统分析食品安全问题的特征和原因,最后提出治理小微企业食品安全问题的对策：完善相关法律制度;构建诚信体系;加大对薄弱环节的监管;提高违法成本;发挥其他监管主体的积极性和主动性;积极促成保险公司和小微食品企业的保险意愿。