Valuing Food Store Access: Policy Implications for the Food Stamp Program

Food stamp recipients may lack access to larger stores, reducing the availability of nutritious food. Reliance on smaller stores may have undesirable impacts. Policy alternatives include limiting food stamp redemption to larger stores and subsidizing store development. I estimate that limiting redemption to supermarkets and grocery stores, or supermarkets alone, results in losses ranging from $499.2 million to $1.05 billion, or $1.17 billion to $2.44 billion (respectively) annual loss in food stamp recipient welfare nationwide. The impact of improving access is also significant, ranging from $333.6 million to $931.2 million.     

Digital Yellow River Model

Soil erosion is one of the key concerns in land use management for the Loess Plateau of the Yellow River, where serious soil loss is the root cause of environmental and ecological degradation of the basin. In this paper, a physically-based, distributed-parameter, and continuous erosion prediction model at the river basin scale was developed with the aim of assisting in developing better land use management strategies. The framework, the major supporting techniques, and the typical erosion processes are described. The physical processes of sediment yield and transport in the Loess Plateau are divided into three sub-processes, including the runoff and sediment yield on hillslopes, gravitational erosion in gullies, and hyperconcentrated flow routing in channels. For each sub-process, a physically-based simulation model was developed and embedded into the whole model system. The model system was applied to simulate the runoff and sediment yield in several typical years in the coarse sediment source area of the Loess Plateau, and the simulated results were in reasonably good agreement with the measured values.     

多专题多比例尺水系河网管理模型研究

随着水利行业GIS系统的快速发展和对性能要求的不断提高,迫切需要解决多比例尺水系河网信息统一访问、关系维护等问题。本文提出多专题多比例尺地图管理模型,通过对地图信息依据不同比例尺和专题进行目录层次和专题层次的划分,实现水系河网信息的全国分布式统一管理和共享系统。文中给出了该模型下的水系河网表示和专题中对象间关系,分析了为形成一套基于空间数据库和空间化分析方法的分布式水系河网信息共享系统所需进行的下一步工作。该模型下的全国水系河网管理系统具有较好的可扩展性,支持有效获取不同比例尺的地图,较少信息冗余和保证信息最大可能。     

网络营销创新定位、运行模型及案例分析

网络营销的创新性质包括创新程度和创新效益两个方面。创新程度反映网络营销创新的影响力度,是过程性指标;创新效益反映网络营销的经济效应,是结果性指标。将创新度和效益度垂直相交构成一个二维平面,并将其分别划分为高低两个级别段,可形成四个定位模块,即触网型创新、网络实验型创新、网络营销专家和运营网络型创新。一般情况下,企业网络营销创新往往从触网型创新出发。进而上升到运营网络型创新阶段,但在网络营销实践中,某些创新运动并不是严格地起于触网型创新,而止于运营网络模型,更有逆向运行的情况存在。     

调节对象参数和运动特性随工况变化的分析

水轮机调节对象的许多参数都是随运行工况变化的。以调节对象线性化模型为基础，从1个实例计算人手，计算了不同工况下水轮机传递系数和发电机6个参数的变化情况，进而计算这些参数变化对捌节对象特征根的影响。通过汁算表明，其水力振荡衰减速度与出力有关．而系统的其他运动特性随工况变化较小。     

三峡蓄水初期水库近坝区水环境特性分析

通过现场观测和数值模拟的方法，对三峡水库近坝区在蓄水初期的水流和水环境特性进行了 分析。对蓄水初期的溶解氧、BOD、COD和NH3-N、Cu等水质参数进行了观测，将蓄水初期水质资料与蓄水之前的结果进行了对比，分析了近坝区水环境变化趋势。采用大涡模拟紊流模型，考虑水体表面的热交换，对三峡近坝区的流动和水温分布特性进行了模拟。研究结果表明，三峡水库蓄水初期近坝区水流特性明显改变，主要表现为水深增加、流速变缓，部分地段有回流区出现。水质指标变化不明显，坝前断面溶解氧浓度、悬浮物浓度有所降低，和悬浮物密切相关的污染物总磷、重金属也随之降低；蓄水初期139m水位时坝前水域尚没有出现温度分层现象。     

新型废水厌氧处理工艺——内循环厌氧反应器

介绍内循环(IC)厌氧反应器的发展、基本结构、运行机理。分析该反应器的工艺过程,指出该工艺具有处理效率高、抗冲击能力强等优点。针对IC反应器存在的缺陷,人们对该反应器进行技术改进:通过提高它的内循环的气量进行处理低浓度有机废水;增加外循环装置缩短IC反应器的启动周期。     

黑板型信息融合专家系统在水环境监测中的应用

现代水环境监测系统是一个具有现代高性能、多层次的复杂系统,这要求多个(种、异质)传感器在不同尺度上对水环境进行观测。探讨和分析了信息融合技术应用于水环境监测的特点,提出了一种运用专家系统和黑板理论的水环境监测信息融合结构框架。     

Generalizations of Ho–Lee’s binomial interest rate model I: from one- to multi-factor

In this paper a multi-factor generalization of Ho–Lee model is proposed. In sharp contrast to the classical Ho–Lee, this generalization allows for those movements other than parallel shifts, while it still is described by a recombining tree, and is a process with stationary independent increments to be compatible with principal component analysis. Based on the model, generalizations of duration-based hedging are proposed. A continuous-time limit of the model is also discussed. This research was supported by Open Research Center Project for Private Universities: matching fund subsidy from MEXT, 2004–2008 and also by Grants-in-Aids for Scientific Research (No. 18540146) from the Japan Society for Promotion of Sciences.     

对改革供电企业变电检修现行管理模式的探讨

提出了重组专业化的变电检修总公司的战略思路,对电网企业与总公司之间发展新型关系进行了探讨,指出以战略思维构筑战略联盟,保持合作联盟,实现共赢与发展.分析虽是对检修体制改革,同时也是对安全生产管理体制的变革,有利于供电企业的安全生产管理.