Time Inhomogeneous Multiple Volatility Modeling

Price variations at speculative markets exhibit positive autocorrelationand cross correlation. Due to large parameter spaces necessaryfor joint modeling of variances and covariances, multivariateparametric volatility models become easily intractable in practice.We propose an adaptive procedure that identifies periods ofsecond-order homogeneity for each moment in time. To overcomethe high dimensionality of the problem we transform the multivariateseries into a set of univariate processes. We discuss thoroughlythe implementation of the adaptive technique. Theoretical andMonte Carlo results are given. We provide two applications ofthe new method. For a bivariate exchange rate series we comparethe multivariate GARCH approach with our method and find thelatter to be more in line with the underlying assumption ofindependently distributed innovations. Analyzing a 23-dimensionalvector of asset returns we underscore the case for adaptivemodeling in high-dimensional systems.     

Interpoint Distance Test of Homogeneity for Multivariate Mixture Models

Finite mixtures offer a rich class of distributions for modelling of a variety of random phenomena in numerous fields of study. Using the sample interpoint distances (IPDs), we propose the IPD‐test statistic for testing the hypothesis of homogeneity of mixture of multivariate power series distribution or multivariate normal distribution. We derive the distribution of the IPDs that are drawn from a finite mixture of the multivariate power series distribution and multivariate normal distribution. Based on the empirical distribution of the IPDs, we construct a bootstrap test of homogeneity for other multivariate finite mixture models. The IPD test is applied to mixture models for matrix‐valued distributions and a test of homogeneity for Wishart mixture is presented. Numerical comparisons show that IPD test has accurate type I errors and is more powerful in most multivariate cases than the expectation–maximization (EM) test and modified likelihood ratio test.     

Efficient resource allocation under multi-unit demand

We study resource allocation with multi-unit demand, such as the allocation of courses to students. In contrast to the case of single-unit demand, no stable mechanism, not even the (student-proposing) deferred acceptance algorithm, achieves desirable properties: it is not strategy-proof and the resulting allocation is not even weakly efficient under submitted preferences. We characterize the priority structure of courses over students under which stability is consistent with strategy-proofness or efficiency. We show that stability is compatible with strategy-proofness or efficiency if and only if the priority structure is essentially homogeneous. This result suggests that efficient allocation under multi-unit demand is difficult and that the use of stable mechanisms may not deliver desirable outcomes.     

行业同质性与事务所行业专门化战略——来自中国审计市场的经验证据

本文考察了在中国审计市场环境下行业特征对事务所行业专门化战略的影响。研究发现,行业同质性越高,事务所在该行业的市场份额和组合份额也越高。该结论表明,行业内客户经营越相似,事务所越容易将行业专门化投资获得的行业知识和行业审计程序在行业内不同客户的审计过程中快速有效地分享,因此,事务所越倾向于在该行业进行专门化投资以获得低成本的竞争优势。本文的研究结论可以为事务所行业专门化投资决策提供经验证据,并为事务所通过行业专门化战略实现做大做强提供有益的途径。     

从文化要素的设计视角谈 旅行社专线产品同质化现象的解决之道

此文从文化要素的角度重新审视了旅行社专线产品,在分析了旅行社专线产品的同质化现状和文化要素的内涵后,明确了注入文化要素在旅行社专线产品设计中的重要性,并面向实践针对性地提出了产品设计中文化要素的选择策略。     

边际效用递减规律的再发现

本文的成果主要体现在两个方面:第一,将时间维度导入效用函数,实现了对边际效用递减规律认识的一次真正的飞跃;第二,将需求在需求要素的层次上进行分解,使边际效用递减规律有了更为准确和牢靠的基础。在这两个成果的基础上,对效用的可测量性、商品的同质性假说等问题进生了前瞻性的探讨。     

“陌生化”理论视角下的新闻同质化探析

目前各大媒体的新闻同质化现象十分严重，新闻的品味和质量日益下降，其内容愈加庸俗、无聊。新闻同质化导致了资源的浪费，并使受众对媒体的忠诚度和信任度下降，也使一部分人对媒体报道的相关内容产生了逆反心理。因此，应从传播者对新闻报道的手段和策略方面，用“陌生化”理论来破解新闻同质化的困境。     

Structural measurement errors in nonseparable models

This paper considers measurement error from a new perspective. In surveys, response errors are often caused by the fact that respondents recall past events and quantities imperfectly. We explore the consequences of limited recall for the identification of marginal effects. Our identification approach is entirely nonparametric, using Matzkin-type nonseparable models that nest a large class of potential structural models. We show that measurement error due to limited recall will generally exhibit nonstandard behavior, in particular be nonclassical and differential, even for left-hand side variables in linear models. We establish that information reduction by individuals is the critical issue for the severity of recall measurement error. In order to detect information reduction, we propose a nonparametric test statistic. Finally, we propose bounds to address identification problems resulting from recall errors. We illustrate our theoretical findings using real-world data on food consumption.     

The effects of macroeconomic stability on foreign trade. An analysis for Spain, 1986–2000

Two main factors underlie the rebirth of interest in the study of the influence of the real exchange rate on trade, the reduction of its volatility and the current trend towards price stability. The objective of this study is to analyse the effects of the process of nominal convergence, required of the European member states for the fulfilment of monetary integration, on foreign trade flows. The case of Spain, which is especially interesting in this context, is studied for the period 1986 to 2000. The results of estimating the aggregate functions of the export and import of goods shows how macroeconomic stability has altered the behaviour of trade with respect to the two basic determinants – income and prices – how it has caused a significant structural change in the real exchange rate and, finally, how it has laid the explanatory bases for transactions in the twenty-first century with the single currency – the euro.     

The estimation of profit efficiency

This article discusses a way of solving the ‘Greene Problem’ that has been termed for a technical difficulty in estimating a profit system with technical and allocative inefficiencies. As the ‘Greene Problem’ is due to the existence of unobserved technical inefficiency interactive in a nonlinear form, the article proposes a use of homogeneity in technology to untangle the nonlinear form, enabling the estimation of a profit system as well as the identification of the source of inefficiencies.