Missing Markets and Redundant Reservoirs

This paper uses a two-sector, two-period,spatial model of groundwater usage withstochastic surface water supply to illustratethe potential for the suboptimal management ofthe timing of groundwater uses. A ``timeprofile externality' is said to exist when thetiming of groundwater extraction by one set ofusers impacts on the time profile of wateravailability to another set of users. Theexistence of the time of use externalitydepends on the presence of importantdifferences in the preferences between thecontrol and non-control sectors. It alsodepends on the absence of the markets thatwould internalise these differences. Oneimportant implication of the existence of suchexternalities is that they can inducesub-optimal insurance investments in the formof water storage capital, i.e., unnecessarysurface water reservoirs.     

Prevention versus Treatment under Precautionary Regulation: A Case Study of Groundwater Contamination under Uncertainty

Policy discussions on agricultural pollution problems characterize prevention as more cost effective and precautionary than ex post treatment. We derive conditions under which treatment alone is more cost effective in situations involving multiple sources of emissions, multiple sites affected, and a commonly used precautionary approach to uncertainty. We also show that a greater degree of precaution can result in less reliance on prevention. An empirical case study indicates that treatment alone is the most cost-effective means of dealing with nitrate in most Maryland community water system wells. The use of leaching prevention measures is restricted to the most intensive poultry producing areas. The incremental cost of precaution is substantial.     

基于遗传算法的核函数参数优化

核主分量分析是一种输入输出特征非线性变换技术。选择最优或接近最优的非线性变换核函数参数,使类的可分性测度最大,是KPCA应用于特征提取的关键。本文采用高斯变异遗传算法作优化技术,实现了KPCA和GA的集成,适合核函数参数的优化选择。仿真表明,该技术可行、有效。     

Joint Quantity/Quality Management of Groundwater

Economic literature on groundwater managementhas traditionally been split into two areas: there are papers that evaluate different schemes of dynamicaquifer management, considering that pumping costs vary with stock but ignoring water quality. On the other hand, there are papers that considercontamination problems caused by specificpollutants. This paper presents two alternative models for joint quantity-quality management, and it shows that existing models are in fact special cases of these. The framework isdynamic and considers both the stock of waterquantity and a stock measure of water quality. Optimal taxes are derived, and shown to be different from those in existing quantity-only or quality-only models. Implementationproblems are briefly discussed.     

Ex-post full surplus extraction,straightforwardly

Consider an estimate of the common value of an auctioned asset that is symmetric in the bidders’ types. Such an estimate can be represented solely in terms of the order statistics of those types. This representation forms the basis for a pricing rule yielding truthful bidding as an equilibrium, whether bidders’ types are affiliated or independent. We highlight the link between the estimator and full surplus extraction, providing a necessary and sufficient condition for ex-post full surplus extraction, including the possibility of independent types. The results offer sharp insights into the strengths and limits of simple auctions by identifying the source of informational rents in such environments. Harstad acknowledges hospitable accommodation by the Fuqua School of Business, Duke University, and the Olin School of Business, Washington University in St. Louis, during parts of this research. We are grateful for comments and suggestions from Richard McLean and Jeroen Swinkels.     

Uncertain Climate Change in an Intergenerational Planning Model

A three-generation planning model incorporating uncertain climate change is developed. Each generation features a production activity based on capital and an exhaustible resource. An irreversible climate change may occur in period two or three, reducing the productivity for this and the remaining generation. The model is solved by stochastic dynamic programming. If the climate impact and climate change probability is constant, the optimal period one (and two) resource extraction is larger than for the reference case of climate stability. If, however, climate impact and climate change probability increases with increased aggregate resource use, this result is reversed.     

高硫减压渣油加工方案的技术经济比较

对中国石化齐鲁分公司高硫减压渣油两种生产方案,即减压深拔工艺生产重交沥青和VRDS-FCC组合工艺生产轻质油品进行技术经济比较.结果表明:在公司裂解原料不能完全自给的前提下,VRDS-FCC组合工艺的单位利润优于减压深拔工艺,但随着重交沥青价格的上升,VRDS-FCC组合工艺的优势将逐渐减弱.     

因子分析中公因子提取方法的比较与选择

近代和现代统计分析方法中，因子分析是最重要的方法之一。因子分析中有7种提取公因子的方法，其中主成分法、极大似然法和主轴因子法是常用的方法。在着重解析这三种方法基本数学过程的基础上，对其适用条件和应用注意事项进行了比较，最后结合实例比较了不同公因子提取方法的结果，并对提取公因子过程中出现的问题给出了可能的解决办法。     

The cost of unconventional gas extraction: A hedonic analysis

We focus on identification and estimation of potentially negative environmental impacts of unconventional natural gas extraction on property values in the United States and advance previous research by contributing new data and new identification strategies for isolating these potential impacts. Our study area consists of two counties in Pennsylvania that are home to large amounts of unconventional natural gas extraction but are otherwise isolated from other resource extraction industries or large urban areas. We deploy parametric, semi-parametric, and matching hedonic regression models that include recent quasi-experimental methods and, in contrast to previous research and much popular intuition, we fail to find robust significance that negative environmental externalities of natural gas extraction are manifested in nearby property values. While there may be plausible risks associated with unconventional natural gas extraction, we do not find consistent evidence to suggest that these risks significantly affect nearby property values.     

Measuring Production and Irrigation Efficiencies of Rice Farms: Evidence from the Punjab Province,Pakistan

We employ a non‐parametric approach, data envelopment analysis, to estimate the technical and irrigation efficiency of rice farms in the Punjab Province of Pakistan. We use a cross‐sectional dataset of 80 rice growers, including 45 tube‐well owners and 35 water buyers. Mean technical efficiency scores show that tube‐well owners and water buyers are operating at fairly high efficiency levels, indicating that access to technology is not a major constraint. However, irrigation inefficiency is pronounced, with water buyers being more inefficient than tube‐well owners. A bootstrap truncated regression is used to investigate the determinants of technical and irrigation efficiency. We suggest that groundwater management policies should be designed to address efficiency enhancing factors such as knowledge of crop water consumption requirement, better credit opportunities, outreach extension services and training programs.