Multivariate normal estimation: the case (n < p)

Estimation in the multivariate context when the number of observations available is less than the number of variables is a classical theoretical problem. In order to ensure estimability, one has to assume certain constraints on the parameters. A method for maximum likelihood estimation under constraints is proposed to solve this problem. Even in the extreme case where only a single multivariate observation is available, this may provide a feasible solution. It simultaneously provides a simple, straightforward methodology to allow for specific structures within and between covariance matrices of several populations. This methodology yields exact maximum likelihood estimates.     

On the construction of optimal experimental designs: a penalty approach

Tn optimal experimental design theory there are well-known situations, in which additional constraints are implied to the design set. These constraints destroy in general the simplex structure of the set of feasible points of the design set. Thus the available iteration procedures for the unrestricted case are no longer applicable.

In this paper a penalty approach is suggested which transforms the restricted problem to the unrestricted case and allows the application of well-known algorithms such as the Fedorov-Wynn-type or the projected gradient procedure.     

金融发展、融资约束与战略性新兴产业发展

战略性新兴产业发展需要大量的资金投入,过高的外部融资成本已经成为阻碍战略性新兴产业发展的重要因素.促进战略性新兴产业发展,已经成为一个亟待解决的问题.文章利用2011-2014年七大战略性新兴产业422家上市公司15个季度的面板数据,分别考察了中国银行业与股票市场发展对战略性新兴产业发展的影响.实证结果显示,七大战略性新兴产业的融资约束具有异质性,节能环保产业、高端装备制造业和生物医药产业融资约束较小,新材料、新一代信息技术、新能源汽车和新能源产业具有更大的融资约束.进一步研究发现,金融发展缓解了战略性新兴产业的融资约束,其中股票市场发展较银行发展更能缓解战略性新兴产业的融资约束.     

组织特点、外部约束与行业协会能力

构建行业协会制度能力和服务能力测度指标,实证研究表明:协会组织特点、外部约束对于制度能力以及制度能力对于服务能力具有影响。组织特点中,协会兼职或离退休官员的存在不利于协会制度能力提高,尤其是离退休官员。收入虽然对制度能力没影响,但显著影响了服务能力。外部约束中,行业竞争不利于协会制度能力,也没有影响服务能力,反而容易诱发协会寻租活动。协会间竞争对于制度能力、服务能力都没有影响,但对寻租活动抑制效果显著。政策只对协会促进会员遵守规则的制度能力具有正向作用,对协会服务能力提升没有产生效果,仅减少了协会寻租可能。制度能力对于协会总体服务能力和正向服务能力都具有积极作用,而对于负向能力没有影响。     

减排约束下中国天然气供需安全评价:2006-2014年

为准确把握中国天然气供需安全状态,以2006-2014年的数据为样本,在模糊隶属度函数量化指标值的基础上,运用层次分析法(AHP)和熵值法确定指标权重,基于线性加权和函数计算均方根进行综合评价。结果表明:(1)中国天然气供需安全指数呈现"N形"波动,2006-2007年天然气供需安全指数上升。2007-2013年天然气供需安全指数年均下降1.7979。2013年以来天然气供需安全指数开始回升,天然气供需安全压力有所缓解。(2)天然气供应安全指数从2006年的17.5914下降到2013年的0.1556,峰谷差17.4359。天然气需求安全指数呈现"W形"波动。天然气市场安全指数相对稳定,2013年以来略有上升,天然气市场风险逐年下降。(3)天然气供需安全很大程度上取决于天然气供应是否安全。因此,建议从确保天然气稳定供应、提高天然气使用效率和降低市场风险方面采取措施,维护天然气供需安全。     

Imagined interactions,family money management patterns and coalitions,and attitudes toward money and credit

This study explores the imagined interactions college students have with their parents about money and credit, their attitudes toward credit and money, the ways they say their parents deal with financial decisions, and the communication coalitions regarding finances they perceive existing within their family. Students’ imagined interaction pleasantness is greatest when parents jointly form a plan for paying off credit card debt and lowest when parents argue. When family coalitions exist, students report more frequent imagined interactions. Imagined interaction frequency and pleasantness are related to credit and money attitudes.

A constitutional theory of the family

The paper re-examines the idea that a family can be viewed as a community governed by a self-enforcing constitution, and extends existing results in two directions. First, it identifies the circumstances in which a constitution is renegotiation-proof. Second, it introduces parental altruism. The behavioural and policy implications are illustrated by showing the effects of public pensions and credit rationing. These implications are not much affected by whether altruism is assumed or not, but contrast sharply with those of more conventional models.

中国资产证券化信用增级的法律环境问题

资产证券化作为一种新的融资方式,在处置不良资产方面具有明显的作用。信用增级是资产证券化的两大核心技术之一,在当前中国信用体系尚不完善的情况下,信用增级显得尤为重要。信用增级包括内部信用增级和外部信用增级,有效实施这两种信用增级方式在现阶段均存在一定的法律障碍。尽快制定专门的资产证券化法,努力完善信用法律环境,才能保证中国资产证券化的顺利实施。     

Macro-Economic Factors in Credit Risk Calculations: Including Time-Varying Covariates in Mixture Cure Models

The prediction of the time of default in a credit risk setting via survival analysis needs to take a high censoring rate into account. This rate is because default does not occur for the majority of debtors. Mixture cure models allow the part of the loan population that is unsusceptible to default to be modeled, distinct from time of default for the susceptible population. In this article, we extend the mixture cure model to include time-varying covariates. We illustrate the method via simulations and by incorporating macro-economic factors as predictors for an actual bank dataset.