On the stability of the risk hull method for projection estimators

We consider in this paper the regularization by projection of a linear inverse problem Y=Af+εξ$Y=\mathit{Af}+\epsilon \xi$ where ξ$\xi$ denotes a Gaussian white noise, A   a compact operator and ε>0$\epsilon >0$ a noise level. Compared to the standard unbiased risk estimation (URE) method, the risk hull minimization (RHM) procedure presents a very interesting numerical behavior. However, the regularization in the singular value decomposition setting requires the knowledge of the eigenvalues of A$A$. Here, we deal with noisy eigenvalues: only observations on this sequence are available. We study the efficiency of the RHM method in this situation. More generally, we shed light on some properties usually related to the regularization with a noisy operator.     

中国证券业总产出和增加值测算研究

 金融机构总产出和增加值的测算是一项基础性的研究工作。与传统测算方法不同,本文借鉴经济合作和发展组织（OECD）提出的使用者成本法,把证券业视为生产性服务活动,并结合我国的实际情况,从服务的角度初步提出了我国证券业总产出和增加值的测算框架。并提出了未来研究改进的方向。     

技术特征、关系结构与社会化购买行为

社会化媒体技术与社会关系网络促进了社会化商务(SC)的价值创造,如何有效利用技术与用户的关系结构是 SC 企业提高其平台购买转化率的关键． 从双重视角探索技术与关系如何影响用户购买决策,基于刺激―机体―反应框架,构建了以技术可供性和强、弱关系为刺激因素,信息诊断性和意外发现性为内在机体状态,社会化购买意向为“反应”的理论模型,探索了用户社会化购买行为的发生机制． 以具有社会化购买体验的微信用户作为研究对象,运用 SmartPLS 3.0 对模型进行了路径检验和假设分析． 研究结果发现: 技术可供性与弱关系对信息诊断性和信息意外发现性具有正向影响; 弱关系对信息意外发现性的影响作用大于强关系; 信息诊断性正向影响信息意外发现性,信息诊断性与意外发现性对社会化购买意向均有显著正向影响; 然而,强关系对信息意外发现性的影响不显著． 信息诊断性与信息意外发现性部分中介了技术可供性对社会化购买意向的影响,完全中介了弱关系对社会化购买意向的影响,信息诊断性部分中介了强关系对社会化购买意向的影响． 为进一步探究社会化购买行为提供 了理论基础和实践指导．     

宏观调控视角下我国土地储备法律制度的完善

世界各国的土地储备制度主要有以下几种类型:土地银行制度、土地优先购买权制度、土地规划制度、土地征用制度.土地储备制度于20世纪90年代从香港地区引进以后,已成为我国许多地方政府调控土地市场的重要手段.但是目前我国土地储备制度存在诸多问题:土地储备法律很不完善;土地储备中的一些基本制度欠缺.因此,应当借鉴国外和相关地区的经验来完善我国的土地储备法律制度.     

A lost family-planning regime in eighteenth-century Ceylon

Based on Dutch colonial registers (thombos), this paper reconstructs fertility for two districts in Ceylon, 1756–68. It overcomes challenges in data quality by establishing the outer bounds of plausible estimates in a series of scenarios. Among these, total fertility rates (TFRs) averaged 5.5 in one district, but only 2.7 in the other. These figures exclude the victims of infanticide, a custom noted in European travelogues between about 1660 and 1820. Sex ratios among children differed depending on the number of older siblings, and overall, 27?per cent of girls are missing in one district and 57?per cent in the other. There was little significant variation either in the TFR or the sex ratio by socio-economic status, suggesting that poverty was not a key factor in motivating infanticides. Instead, we argue that at least parts of Ceylon had a forward-looking culture of family planning in the eighteenth century, which was lost in subsequent decades.     

C2C市场上消费者从众决策研究——基于面板数据模型

电子商务市场蓬勃发展的同时,也存在严重的信息不对称现象,给消费者带来极大的购物风险。文章基于信息不对称理论,利用淘宝网交易数据对 C2C 市场上消费者的从众决策行为进行研究。研究发现 C2C 市场上店铺的日销量在店铺间存在二八分布的特征,说明网络消费者在购买商品时有从众行为。基于面板模型对店铺市场份额的研究表明,店铺历史销量信息对消费者选择店铺的决策有显著正向影响,而店铺信用对消费者决策的影响并不显著。因此,建议 C2C 交易平台增加退货量指标、动态销量图以及销量和价格的相互对应信息等,以促进消费者理性购物。     

富裕社会中贫困的消除：加尔布雷思的探究及启示

贫困表现为人的基本需要得不到满足,“富裕社会”中的贫困表现为私人生产、物质生产的过剩和公共生产、精神生产的不足。加尔布雷思认为,美国“富裕社会”中贫困的原因是不平衡的“二元经济体系”,只要实行“新社会主义”,实现“计划体系”和“市场体系”的平衡,就能解决“富裕”背后的贫困问题。由于这一设想是以不改变资本主义的经济基础为前提的,所以,只能是一种治标不治本的改良。只有扬弃经济学的“传统智慧”,建构以促进“每个人的自由发展”为目标的“全面生产”经济学,才能从根本上消除“富裕社会”中的贫困问题。     

Simultaneous decomposition of the variance by sources and subgroups – new insights

There are two types of decompositions: of linear combinations of random variables into contributions of individual variables (sources) and associations between them, and of populations into contributions of their subpopulations. Simultaneous treatment of the two types is called for, which takes into account the correlations between sources within subpopulations and between subpopulation means. The expected values of the subcomponents are derived and their sensitivity to correlations among sources within groups and among source group means is conducted. An example is provided, in which the correlations contribute 20--25% to total variability. This additional information is hidden when decompositions are not simultaneous.     

Construction of bivariate and multivariate weighted distributions via conditioning

Weighted distributions (univariate and bivariate) have received widespread attention over the last two decades because of their flexibility for analyzing skewed data. In this article, we propose an alternative method to construct a new family of bivariate and multivariate weighted distributions. For illustrative purposes, some examples of the proposed method are presented. Several structural properties of the bivariate weighted distributions including marginal distributions together with distributions of the minimum and maximum, evaluation of the reliability parameter, and verification of total positivity of order two are also presented. In addition, we provide some multivariate extensions of the proposed models. A real-life data set is used to show the applicability of these bivariate weighted distributions.     

Smoothing the difference-based estimates of variance using variational mode decomposition

We propose a variational mode decomposition approach to estimate the variance function in a nonparametric heteroscedastic fixed design regression model. A data-driven estimator is constructed by applying variational mode decomposition technique to the difference-based initial estimates. The numerical results show that the proposed estimator performs better than the existing variance estimation procedures in the mean square sense.