能源价格波动对中国物价水平的潜在与实际影响

目的/意义原油作为重要的工业原料、大宗商品和战略储备物资,其价格波动对全球经济发展具有重大影响,对原油价格进行预测是能源经济领域的热点研究课题。对国际原油价格预测的主要方法进行系统梳理并展望未来研究方向,有助于该研究领域的纵深发展。设计/方法基于295篇国际期刊文献,对国际油价预测的发展阶段、发表期刊、研究机构等进行归纳总结,然后对近二十年油价预测领域的主要研究方法进行系统梳理和分析,最后对油价预测工作进行评述和趋势展望。结论/发现自2008年金融危机后,油价预测研究快速发展,相关文章主要发表于能源经济领域的权威期刊《Energy Economic》。现有油价预测方法主要包括计量模型、机器学习和混合预测模型。展望未来,利用高频日内交易数据,融合计量和机器学习前沿方法,对原油价格进行区间预测或概率密度预测是值得探索的方向,此外还应深化油价预测结果的实际应用价值。     

关于中国现代史分期问题的思考

目前,史学界对于中国现代史的分期看法不一,形成不同的主张：或以重大政治历史事件为标准,或依据《关于建国以来党的若干历史问题的决议》,或以经济社会发展目标模式为分期标准。这些标准都不符合中国通史的学科分期要求。中国现代史作为通史,其分期应当以社会形态的变迁为标准,应根据社会主义的不同发展模式,将其划分为新民主主义时期或社会主义的准备时期、苏联模式社会主义时期或传统社会主义时期、中国特色社会主义时期或现代社会主义时期。     

A note on spectral estimation for ARMA processes

The standard frequency domain approximation to the Gaussian likelihood of a sample from an ARMA process is considered. The Newton-Raphson and Gauss-Newton numerical maximisation algorithms are evaluated for this approximate likelihood and the relationships between these algorithms and those of Akaike and Hannan explored. In particular it is shown that Hannan's method has certain computational advantages compared to the other spectral estimation methods considered     

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.     

Conditional Akaike Information Criteria for a Class of Poisson Mixture Models with Random Effects

Focusing on the model selection problems in the family of Poisson mixture models (including the Poisson mixture regression model with random effects and zero‐inflated Poisson regression model with random effects), the current paper derives two conditional Akaike information criteria. The criteria are the unbiased estimators of the conditional Akaike information based on the conditional log‐likelihood and the conditional Akaike information based on the joint log‐likelihood, respectively. The derivation is free from the specific parametric assumptions about the conditional mean of the true data‐generating model and applies to different types of estimation methods. Additionally, the derivation is not based on the asymptotic argument. Simulations show that the proposed criteria have promising estimation accuracy. In addition, it is found that the criterion based on the conditional log‐likelihood demonstrates good model selection performance under different scenarios. Two sets of real data are used to illustrate the proposed method.     

从“用频”的角度看现代汉语中的“无标志词/有标志词”与“尊/卑”文化的关系

现代汉语中,词的“无标志/有标志”性与词背后“尊/卑”文化有着很强的对应关系.然而,这种对应关系也存在着不少问题,例如“父/祖父/曾祖父”等反例,必须注意特定的“语言使用者”这一限制性条件.从“用频”的角度出发可以进一步解释“无标志/有标志”性与词背后“尊/卑”文化的具体对应关系.对“司令/总司令”和“保姆/男保姆”这两组例子的分析,可以揭示运用这种对应关系在实际应用过程中的一些重要问题.     

语义角色精细化理论下的题元准则研究

在语义角色精细化理论框架下讨论了英语中的题元角色与论元之间的关系。对题元准则存在的问题进行了分析，介绍了佩里尼的语义角色精细化理论，区分了精细化角色和概括性角色。精细化角色和概括性角色之间存在一条精细化轨道，连接下位的精细化题元关系和上位的语义角色的同时，把精细化题元关系和论元的句法功能联系起来。在任何谓词结构内，每个可见论元都必须充当特定的语义角色，每个语义角色都必须指派给一个可见论元。并对角色精细化题元关系为题元准则具体问题的消解方案进行了讨论。     

Cumulative correspondence analysis using orthogonal polynomials

Taguchi's statistic has long been known to be a more appropriate measure of association of the dependence for ordinal variables compared to the Pearson chi-squared statistic. Therefore, there is some advantage in using Taguchi's statistic in the correspondence analysis context when a two-way contingency table consists at least of an ordinal categorical variable. The aim of this paper, considering the contingency table with two ordinal categorical variables, is to show a decomposition of Taguchi's index into linear, quadratic and higher-order components. This decomposition has been developed using Emerson's orthogonal polynomials. Moreover, two case studies to explain the methodology have been analyzed.     

论坚持“以德为先”选用干部

我们党选用干部标准的思想经历了从毛泽东提出的＂德才兼备＂到胡锦涛明确提出的＂德才兼备、以德为先＂的历史的、理论的发展演变过程。从宏观上和战略上看,坚持＂以德为先＂选用干部,在理论层面和现实需求层面上都具有重大的价值意义。要使＂以德为先＂用人标准不致于流于形式,就必须健全完善与时俱进的党员干部＂德＂之衡量标准。     

试析影响词汇访问速度的关键因素

一些高频词汇在学习者大脑词库中常被存储在底层,如何把这些需要熟练使用的词汇尽可能多地转移到词库表层,以达到词汇访问的自动化,是值得探索和研究的问题。本文从词汇访问频率、词汇意义变化和语境三方面分析影响词汇访问速度的原因,并提出外语学习过程中提高词汇访问速度的建议。