A play-the-winner-type urn design with reduced variability

We propose a new adaptive allocation rule, the drop-the-loser, that randomizes subjects in the course of a trial comparing treatments with dichotomous outcomes. The rule tends to assign more patients to better treatments with the same limiting proportion as the randomized play-the-winner rule. The new design has significantly less variable allocation proportion than the randomized play-the-winner rule. Decrease in variability translates into a gain in statistical power. For some values of success probabilities the drop-the-loser rule has a double advantage over conventional equal allocation in that it has better power and assigns more subjects to the better treatment. Acknowledgments. I thank Stephen Durham, the associate editor, and the referees for their helpful suggestions.     

Simulating the Evolution of the Implied Distribution

Motivated by the implied stochastic volatility literature (Britten–Jones and Neuberger, forthcoming; Derman and Kani, 1997; Ledoit and Santa–Clara, 1998) this paper proposes a new and general method for constructing smile–consistent stochastic volatility models. The method is developed by recognising that option pricing and hedging can be accomplished via the simulation of the implied risk neutral distribution. We devise an algorithm for the simulation of the implied distribution, when the first two moments change over time. The algorithm can be implemented easily, and it is based on an economic interpretation of the concept of mixture of distributions. It can also be generalised to cases where more complicated forms for the mixture are assumed.     

软件无线电及其实现方案的研究

在介绍软件无线电的产生、基本概念和系统结构的同时，分析了实现软件无线电的关键技术，并给出了基于目前器件技术水平的中频软件无线电流程框图的折衷方案，最后指出软件无线电技术的美好前景。     

经济增长方式范式转变研究

文章从自然资源价值评估机制和制度安排的优化机制两方面阐述了经济增长方式转变的动力机制，认为应该通过完善制度体系、建立技术支撑体系以及提高公众参与循环经济意识，实现我国经济增长方式的转变。     

Factors affecting households’ seafood purchasing decisions in Auckland,New Zealand: an empirical analysis

This paper uses the binary choice model to identify the factors that are significantly influencing the household purchase decisions of seafood products for home consumption in Auckland, New Zealand. It is found that ‘quality’ and ‘cooking easiness’ are the main product attributes that significantly influence households’ choices of seafood in Auckland. Also, the representative household has shown a strong preference for fresh and other alternative seafood products, including processed, smoked and canned, over frozen products. Retail outlets are found to be more attractive to the household purchasing seafood for home consumption. The New Zealand seafood industry may find this baseline study useful as a guide to developing future research structure on the domestic market.     

What Prompts the People＇s Bank of China to Change Its Monetary Policy Stance？ Evidence from a Discrete Choice Model

In the present paper, we model the policy stance of the People＇s Bank of China （PBC） as a latent variable, and the discrete changes in the reserve requirement ratio, policy interest rates, and the scale of open market operations are taken as signals of movement of this latent variable. We run a discrete choice regression that relates these observed indicators of policy stance to major trends of macroeconomic and financial developments, which are represented by common factors extracted from a large number of variables. The predicted value of the estimated model can then be interpreted as the implicit policy stance of the PBC. In a second step, we estimate how much of the variation in the PBC＇ s implicit stance can be explained by measures of its policy objectives on inflation, growth and financial stability. We find that deviations of CPI inflation from an implicit target and deviations of broad money growth from the announced targets, but not output gaps, figure significantly in the PBC＇s policy changes.     

混合拉曼/EDFA放大器及其在DWDM中的应用

本文综述了混合拉曼／掺饵光纤放大器（HFA）的工作原理，结构和特点，介绍了4类HFA基本结构及其实验结果，并通过介绍近年来各类HFA在密集波分复用（DWDM）系统中的应用表明了HFA在带宽，增益和噪声特性方面的优点。     

Statistics for Studies of Human Welfare

Developments in the recent past have substantially increased our ability to measure, compute, and communicate. We take the view that a corresponding improved understanding of processes in the life sciences will come about only through more intensive studies of properties of statistical methods and algorithms and transparent, open source computing environments.     

THE SQUARED ORNSTEIN-UHLENBECK MARKET

We study a complete market containing J assets, each asset contributing to the production of a single commodity at a rate that is a solution to the squared Ornstein-Uhlenbeck (Cox-Ingersoll-Ross) SDE. The assets are owned by K agents with CRRA utility functions, who follow feasible consumption/investment regimes so as to maximize their expected time-additive utility from consumption. We compute the equilibrium for this economy and determine the state-price density process from market clearing. Reducing to a single (representative) agent, and exploiting the relation between the squared-OU and squared-Bessel SDEs, we obtain closed-form expressions for the values of bonds, assets, and options on the total asset value. Typical model parameters are estimated by fitting bond price data, and we use these parameters to price the assets and options numerically. Implications for the total asset price itself as a diffusion are discussed. We also estimate implied volatility surfaces for options and bond yields.