增长性市场条件下垄断定价的实物期权方法

许多研究垄断厂商定价的文献忽视了垄断厂商拥有的调整价格的权利. 事实上,这种调 价的权利等价于厂商拥有的一个实物期权. 基于此,应用实物期权的方法确定了增长性市场条 件下调价权利(调价期权) 的价值,进而研究了垄断厂商的定价行为,给出了企业价值最大化的 条件. 结果表明,在增长性市场中,需求状况的好坏决定了垄断厂商的定价决策是否考虑调价 期权. 并且,当垄断厂商定价考虑其拥有的调价期权的价值时,除一些特殊情形外,边际收益等 于边际成本,不再适用垄断厂商的定价决策     

股指期货价格非线性均值回复特性实证研究

用ESTAR 模型对香港恒生指数期货933、9312、943 合约及S&P 500 指数期货933、9312、 943 合约价格进行了实证研究,发现恒生指数期货933、9312 合约实际价格呈现非线性均值回 复,而其他各合约实际价格呈现线性均值回复. 结论:由于股票现货没有卖空机制使套利成本 较大,抑制了套利行为,导致期货合约实际价格呈现非线性. 在股票现货没有卖空机制的市场 条件下,单向套利的机会要比成熟的市场更多.     

How Autonomous are Public Corporations in Hong Kong? The Case of the Airport Authority

This article examines the degree of autonomy of Hong Kong’s Airport Authority (AA). Traditionally, airport management in Hong Kong was the responsibility of the government’s Civil Aviation Department. The AA was established in 1995 to manage the new international airport at Chek Lap Kok which opened in 1998. It was expected to run as a commercial enterprise but, because of its strategic importance, there was concern that it should not become an independent empire detached from government control. As a hybrid type of organization, the AA has moved steadily towards full commercialization. The government has also put its privatization on the agenda. Its transformation may have some implications for the redefinition of the future autonomy boundaries of public corporations in Hong Kong.

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An access network design problem with end-to-end QoS constraints

In this paper, we present an access network design problem with end-to-end quality of service (QoS) requirement. The problem can be conceptualized as a two-level hierarchical location-allocation problem on the tree topology with nonlinear side constraints. The objective function of the nonlinear mixed integer programming model minimizes the total cost of switch and fiber cable, while satisfying demand within the prescribed level of QoS. By exploiting the inherent structure of the nonlinear QoS constraints, we develop linearization techniques for finding an optimal solution. Also, we devise an effective exact optimal algorithm within the context of disjunctive constraint generation. We present promising computational results that demonstrate the effectiveness of the proposed solution procedure.     

Diagnostics for quasi-likelihood nonlinear models

Quasi-likelihood nonlinear models (QLNMs) are an extension of generalized linear model and include a widen class of models as special cases. This article investigates some diagnostic methods in QLNMs. An equivalency between a case-deletion model and a mean-shift outlier model in QLNM is established. Two simulation study and a real dataset are used to illustrate the proposed diagnostic methods.     

Corrected maximum likelihood estimators in heteroscedastic symmetric nonlinear models

In this article, we derive general matrix formulae for second-order biases of maximum likelihood estimators (MLEs) in a class of heteroscedastic symmetric nonlinear regression models, thus generalizing some results in the literature. This class of regression models includes all symmetric continuous distributions, and has a wide range of practical applications in various fields such as engineering, biology, medicine and economics, among others. The variety of distributions with different kurtosis coefficients than the normal may give more flexibility in the choice of an appropriate distribution, particularly to accommodate outlying and influential observations. We derive a joint iterative process for estimating the mean and dispersion parameters. We also present simulation studies for the biases of the MLEs.     

Robust Bayesian nonlinear mixed‐effects modeling of time to positivity in tuberculosis trials

Early phase 2 tuberculosis (TB) trials are conducted to characterize the early bactericidal activity (EBA) of anti‐TB drugs. The EBA of anti‐TB drugs has conventionally been calculated as the rate of decline in colony forming unit (CFU) count during the first 14 days of treatment. The measurement of CFU count, however, is expensive and prone to contamination. Alternatively to CFU count, time to positivity (TTP), which is a potential biomarker for long‐term efficacy of anti‐TB drugs, can be used to characterize EBA. The current Bayesian nonlinear mixed‐effects (NLME) regression model for TTP data, however, lacks robustness to gross outliers that often are present in the data. The conventional way of handling such outliers involves their identification by visual inspection and subsequent exclusion from the analysis. However, this process can be questioned because of its subjective nature. For this reason, we fitted robust versions of the Bayesian nonlinear mixed‐effects regression model to a wide range of TTP datasets. The performance of the explored models was assessed through model comparison statistics and a simulation study. We conclude that fitting a robust model to TTP data obviates the need for explicit identification and subsequent “deletion” of outliers but ensures that gross outliers exert no undue influence on model fits. We recommend that the current practice of fitting conventional normal theory models be abandoned in favor of fitting robust models to TTP data.     

Modelling of connected processes

The problem of comparing, contrasting and combining information from different sets of data is an enduring one in many practical applications of statistics. A specific problem of combining information from different sources arose in integrating information from three different sets of data generated by three different sampling campaigns at the input stage as well as at the output stage of a grey-water treatment process. For each stage, a common process trend function needs to be estimated to describe the input and output material process behaviours. Once the common input and output process models are established, it is required to estimate the efficiency of the grey-water treatment method. A synthesized tool for modelling different sets of process data is created by assembling and organizing a number of existing techniques: (i) a mixed model of fixed and random effects, extended to allow for a nonlinear fixed effect, (ii) variogram modelling, a geostatistical technique, (iii) a weighted least squares regression embedded in an iterative maximum-likelihood technique to handle linear/nonlinear fixed and random effects and (iv) a formulation of a transfer-function model for the input and output processes together with a corresponding nonlinear maximum-likelihood method for estimation of a transfer function. The synthesized tool is demonstrated, in a new case study, to contrast and combine information from connected process models and to determine the change in one quality characteristic, namely pH, of the input and output materials of a grey-water filtering process.     

构建省以下政府间合理财政关系问题研究——兼论“省管县”体制向常态化发展的可能性及路径

对于“省管县”财政体制改革的认识，不能仅定位于压缩财政层级或县域政区财政脱困的权宜之计，必须将其提升至地方行政管理体制变革的高度。中国的财政管理体制改革必须在行政管理体制改革的大背景中找到自己的位置。本文认为，应逐步通过解除市领导县的管理体制，重新整合县域行政辖区，以及必要的省级行政区划的调整，在形成了一个相对合理地地方行政管理层级架构之后，方能营造出构建相对合理的地方政府间财政关系的可能性，进而使得“省管县”财政管理体制成为一种常态化的模式。     

A diagnostic statistic for functional-coefficient autoregressive models

In this paper, functional coefficient autoregressive (FAR) models proposed by Chen and Tsay (1993) are considered. We propose a diagnostic statistic for FAR models constructed by comparing between parametric and nonparametric estimators of the functional form of the FAR models. We show asymptotic properties of our statistic mathematically and it can be applied to the estimation of the delay parameter and the specification of the functional form of FAR models.