On the construction of a class of efficient row-column designs

In this paper a method for the construction of a class of row-column designs with good statistical properties and high efficiency is presented. The class of designs produced is shown to exhibit balance, orthogonality and adjusted orthogonality. The efficiencies of these designs are investigated in detail, and they are shown to be very high, and possibly maximal in some cases.     

On the distribution of quadratic functionals of the ordinary and fractional Brownian motions

In this paper we discuss some distributional properties of quadratic functionals of the ordinary and fractional Brownian motions (fBms). As far as the ordinary Brownian motion (Bm) is concerned, those properties have been established extensively. A transition from the Bm to the fBm is not straightforward. Some difficulties associated with dealing with the fBm are explained, and a way to solving the problem is indicated, and some conjectures are given.     

On characterizations of the logistic distribution

We modify and extend George and Mudholkar's [1981. A characterization of the logistic distribution by a sample median. Ann. Inst. Statist. Math. 33, 125–129] characterization result about the logistic distribution, which is in terms of the sample median and Laplace distribution. Moreover, we give some new characterization results in terms of the smallest order statistics and the exponential distribution.     

Optimal discrimination designs for exponential regression models

We investigate optimal designs for discriminating between exponential regression models of different complexity, which are widely used in the biological sciences; see, e.g., Landaw [1995. Robust sampling designs for compartmental models under large prior eigenvalue uncertainties. Math. Comput. Biomed. Appl. 181–187] or Gibaldi and Perrier [1982. Pharmacokinetics. Marcel Dekker, New York]. We discuss different approaches for the construction of appropriate optimality criteria, and find sharper upper bounds on the number of support points of locally optimal discrimination designs than those given by Caratheodory's Theorem. These results greatly facilitate the numerical construction of optimal designs. Various examples of optimal designs are then presented and compared to different other designs. Moreover, to protect the experiment against misspecifications of the nonlinear model parameters, we adapt the design criteria such that the resulting designs are robust with respect to such misspecifications and, again, provide several examples, which demonstrate the advantages of our approach.     

“10”在数制转换中的妙用

数制是计算机应用学习的一个关键和难点,本文巧妙地运用“10”来解决这一问题。     

英国高等教育质量保证体系

英国高等教育质量保证体系是在高等教育走向大众化、普及化和教育质量出现下降趋势的情况下建立和发展起来的。这个体系包括严格的外部教育质量评估和完善的校内教育质量保证机制,反映了英国高等教育数百年沉淀下来的充分体现学校神圣责任、以学生为本的办学思路理念、厚重的校园文化和大学精神。     

FROM MAIZE TO HAZE: AGRICULTURAL SHOCKS AND THE GROWTH OF THE MEXICAN DRUG SECTOR

Understanding how economic incentives affect illegal drug production is essential for crafting policies in response to the international drug trade. Policymakers typically face a choice between two strategies: targeting criminal groups via law enforcement, and offering producers incentives to engage in alternate activities. Yet, little is known about how the returns to alternate legal activities affect drug supply. We contribute to this literature by examining how shocks to legal commodity prices affect the drug trade in Mexico. Our analysis exploits exogenous movements in the Mexican maize price stemming from weather conditions in US maize‐growing regions, as well as exports of other major maize producers. Using data on over 2200 municipios spanning 1990–2010, we show that lower prices differentially increased the cultivation of both marijuana and opium poppies in municipios more climatically suited to growing maize. We also find impacts on downstream drug‐trade outcomes, including drug cartel operations and killings perpetrated by these groups. Our findings demonstrate that maize price changes contributed to the burgeoning drug trade in Mexico, and point to the violent consequences of an expanding drug sector.     

Adaptive wavelet estimation of a density from mixtures under multiplicative censoring

In this paper, a mixture model under multiplicative censoring is considered. We investigate the estimation of a component of the mixture (a density) from the observations. A new adaptive estimator based on wavelets and a hard thresholding rule is constructed for this problem. Under mild assumptions on the model, we study its asymptotic properties by determining an upper bound of the mean integrated squared error over a wide range of Besov balls. We prove that the obtained upper bound is sharp.