基于联合分析的新产品市场占有率预测——学生笔记本电脑市场的实证分析

市场竞争日趋激烈,企业要想在市场竞争中立于不败之地,在开发一种新产品时,势必要预测新产品在市场上的份额,本文在简述联合分析基本原理的基础上,以开发学生笔记本电脑市场的新产品为例,采用联合分析方法中的最大效用值法来预测新产品的市场占有率。     

Smooth estimators for estimating order restricted scale parameters of two gamma distributions

We consider the problem of component-wise estimation of ordered scale parameters of two gamma populations, when it is known apriori which population corresponds to each ordered parameter. Under the scale equivariant squared error loss function, smooth estimators that improve upon the best scale equivariant estimators are derived. These smooth estimators are shown to be generalized Bayes with respect to a non-informative prior. Finally, using Monte Carlo simulations, these improved smooth estimators are compared with the best scale equivariant estimators, their non-smooth improvements obtained in Vijayasree, Misra & Singh (1995), and the restricted maximum likelihood estimators. Acknowledgments. Authors are thankful to a referee for suggestions leading to improved presentation.     

Adaptive two-treatment two-period crossover design for binary treatment responses

Adaptive designs are sometimes used in a phase III clinical trial with the aim, of allocating a larger number of patients to the better treatment. In the present paper, we use some adaptive designs in a two-treatment two-period crossover design where the treatment responses are binary. We use some simple designs to choose between the possible treatment combinations AA, AB, BA or BB. The goal is to use the better treatment a larger proportion of times. We calculate the allocation proportions to the possible treatment combinations and their standard deviations. We also study related inferential problems. Related asymptotics are derived. The proposed procedure is compared with some possible competitors. Finally, we use real data to illustrate the applicability of our proposed design.     

和谐社会的经济学分析

和谐社会构建过程中的公平与效率、选择与激励、资源配置的社会价值总量最大化与社会福利最大化的平衡与协调等问题体现着广大人民群众的根本利益,因此,从经济学的角度上来讲,构建和谐社会就要在实现资源优化配置基础上的社会价值生产总量最大化的同时,实现社会整体福利的最大化。     

Estimating Price Elasticities of Food Trade Functions: How Relevant is the CES‐based Gravity Approach?

The main objective of this article is to examine econometric estimates of price elasticities of food trade functions. We investigate the relevance of the prominent gravity approach. This approach is based on the assumptions of symmetric, monotone, homothetic, Constant Elasticity of Substitution (CES) preferences. We test all these assumptions using intra‐European trade in cheese. In general, the assumptions made on preferences by the gravity approach are not supported by our dataset. The bias induced in the estimated price elasticities is ambiguous.     

UFMC系统在多径衰落信道中的干扰消除

通用滤波多载波(UFMC)是5G通信系统中的关键技术,能够降低带外泄露。但是在多径衰落信道下UFMC系统会受到符号间干扰（ISI）和多普勒效应产生的载波频率偏差的影响,从而使系统的性能下降。为了消除系统中的干扰,提出了一种迭代最大似然算法。该方法主要通过迭代最大似然算法（ML）计算出载波频率偏差,把估计出的结果作为初始值并运用迭代的方法得到最终的载波频率偏差,当达到收敛区间时,迭代结束;最后利用相位旋转的概念补偿载波频率偏差并运用最小二乘算法更新信道响应信息,减少该系统干扰。仿真结果表明,在信噪比大于10 dB时,随着信噪比的增大,算法能够有效地抑制系统中的干扰,提高UFMC系统的性能。     

半参数变系数空间滞后模型的截面极大似然估计

在线性参数空间滞后模型中,解释变量的系数一般假设为固定常数,本文首先放松了这种假设,将解释变量的系数设定为某一变量的未知函数,提出一类全新的半参数变系数空间滞后模型;其次导出了该模型的截面极大似然估计,并证明了该估计的一致性;最后用蒙特卡洛数值模拟方法考察了该估计在小样本条件下的性质,数值模拟结果显示我们提出的估计方法在小样本条件下依然有优良的表现。     

Editorial

Abstract

In this editorial we summarize and comment on papers published in issue 7.1. This is a themed issue, with four of the papers being originally presented at the 9th International Workshop in Spatial Statistics and Econometrics held at the University of Orléans, France. This was organized by Cem Ertur, who was chair of the Scientific Committee, and who has co-edited the current issue and taken the lead in writing about the papers from the Orléans workshop. The first paper, which was not an Orléans paper, is ‘Business Cycles Association in a Small Monetary Union: The Case of Switzerland’ by Alexandra Ferreira-Lopes &; Tiago Sequeira. From Orléans we have ‘QML Estimation of Spatial Dynamic Panel Data Models with Time Varying Spatial Weights Matrices’ by Lung-Fei Lee &; Jihai Yu; ‘Improving the J Test in the SARAR Model by Likelihood-Based Estimation’ by Peter Burridge; ‘The Mundlak Approach in the Spatial Durbin Panel Data Model’ by Nicolas Debarsy; and ‘Spatial Interactions in Hedonic Pricing Models: The Urban Housing Market of Aveiro, Portugal’ by Arnab Bhattacharjee, Eduardo Castro &; João Marques.

RÉSUMÉ Dans la présente communication, nous résumons les communications publiées dans l’édition 7.1, et nous présentons des commentaires sur ces dernières. Il s'agit d'une édition à thème, quatre des communications ayant été présentées initialement au 9^ème atelier international de statistiques et d’économétrie spatiales, à l'université d'Orléans, en France. Cette édition a été organisée par Cem Ertur, qui était président du Comité scientifique, a coédité l’édition actuelle, et a pris le pas dans les communications sur les communications émanant de l'atelier d'Orléans. La première communication, qui n’était pas une communication d'Orléans, est « Association de Cycles commerciaux dans une Union monétaire restreinte: le cas de la Suisse », par Alexandra Ferreira-Lopes &; Tiago Sequeira. D'Orléans, nous avons reçu « Estimation QML de modèles de données de groupe dynamique spatial, avec matrices de poids spatiaux temporalisées », par Lung-Fei Lee &; Jihai Yu; « Optimisation du test « J » dans le modèle SARAR par estimation basée sur les probabilité », par Peter Burridge; « L'approche de Mundlak dans le modèle spatial de données de panel de Durbin », par Nicolas Debarsy; et « Interactions spatiales dans les modèles hédoniques des prix: le marché de l'immobilier urbain d'Aveiro, au Portugal », par Arnab Bhattacharjee, Eduardo Castro &; João Marques.

EXTRACTO En este trabajo resumimos y hacemos comentarios sobre trabajos publicados en la edición 7.1. Esta edición tiene un tema, y cuatro de sus estudios se presentaron originalmente en el Noveno Taller Internacional de Estadísticas Espaciales y Econometría celebrado en la Universidad de Orleans, Francia. Éste fue organizado por Cem Ertur, que presidió el Comité Científico, coeditó la edición actual y adoptó la posición líder en escribir sobre los estudios derivados del taller de trabajo de Orleans. El primer trabajo, que no fue uno de los estudios de Orleans, es la ‘Asociación de Ciclos de Negocios en una Unión Monetaria Pequeña: el Caso de Suiza’ de Alexandra Ferreira-Lopes &; Tiago Sequeira. Los estudios procedentes de Orleans son: ‘Estimación QML de modelos de datos de panel dinámicos espaciales con matrices de pesos espaciales que varían con el tiempo’ de Lung-Fei Lee &; Jihai Yu; ‘Mejora de la prueba J en el modelo SARAR por estimación basada en probabilidad’ de Peter Burridge; ‘El planteamiento Mundlak en el modelo espacial de datos de panel Durbin’ de Nicolas Debarsy; e, ‘Interacciones espaciales en modelos hedónicos de fijación de precios: el mercado de la vivienda urbana de Aveiro, Portugal’ de Arnab Bhattacharjee, Eduardo Castro &; João Marques.

     

Deregulation without apology: A truncated survivor analysis of long-run efficiency gains in the U.S. trucking industry

Deregulation of the U.S. trucking industry is found to have promoted long-run technical efficiency among less-than-truckload carriers of general commodity freight. It did so by exposing all carriers to competition which caused the very largest group, hauling more than five billion ton-miles annually, to lose output share to smaller carrier groups. Their inability to survive in-full implies that efficiency gains were achieved by reducing the extent of operation under decreasing returns to scale. This conclusion conflicts with other recent findings that deregulation promoted long-run efficiency by creating new ways for all carriers, even the very largest, to achieve economies of scale. The discrepancy in conclusions is significant in that previous findings of continuous scale economies, post-deregulation, leave open the possibility of rising industry concentration with all due repercussions on consumer welfare. A more encouraging outlook emerges from the present survivor analysis which finds the minimum efficient size to be below one billion ton-miles annually. This finding strongly supports a prediction of vigorous competition in the future, at least for this one segment of the trucking industry.This study was funded by a Faculty Summer Research Grant from Villanova University. The author acknowledges and appreciates the Office of Research and Sponsored Projects at Villanova for its support.     

Maximum likelihood methods for fitting the burr type XII distribution to multiply (progressively) censored life test data

Summary This paper develops mathematical and computational methodology for fitting, by the method of maximum likelihood (ML), the Burr Type XII distribution to multiply (or progressively) censored life test data. Mathematical expressions are given for approximating the asymptotic variances and covariances of the ML estimates (MLEs) of the parameters of the Burr Type XII distribution. A rigorous mathematical analysis is undertaken to investigate the existence and uniqueness of the MLEs for arbitrary sample data. The methodology of this paper is applied to progressively censored sample data arising in a life test experiment.