A sequential model for cracking down on street markets for illicit drugs

This paper develops a sequential decision-making model for assisting law enforcement officials in allocating resources during a crackdown operation on illicit drug markets. The sequential crackdown model (SCM) considers a probabilistic framework, where the probability of incarceration of a dealer and the probability of dealing are modeled as a function of the size of a drug market, crackdown enforcement level, drug dealer's financial hardship, and other market characteristics.The model was developed and tested in consultation with enforcement officials from Philadelphia, PA and Camden, NJ. We present a detailed, step-by-step implementation scheme for updating parameters on each day of the crackdown. Parameter estimation along with examples of model usage is provided. Through these examples, we illustrate how the SCM could be helpful in understanding the response of illicit drug markets to various enforcement strategies. We further show conditions under which an alternating crackdown policy (referred to as a crackdown-backoff) or a consistent use of maximum possible enforcement would be optimal strategies for managing a drug crackdown operation. Within the context of the model and parameter estimates, we show that a much quicker and less costly collapse could be implemented if the available enforcement resources are increased. Finally, the model provides possible conditions under which a crackdown operation would be unsuccessful in eliminating a drug market.     

一种产品生产规划模型

在对供应链中运输、库存、产品生产计划分析的 基础上,提出了一种解决厂家产品生产规划的混合整数规划 模型。     

长期筹资科学化的初步探索--构建最佳资本结构模型

助计算机用定量方法快速有效的解决长期筹资决策问题是知识经济时代对企业的必然要求。最佳资本结构模型用计算机运筹学的方法来决策不同筹资方式的最优筹资额，以帮助企业实现长期筹资目标同时也是财务管理最终目标——企业价值最大化。     

A note on the determination of A-optimal type block designs under fixed and mixed effects models

In this paper, we consider the problem of estimating a selected set of contrasts between v treatments using a block design consisting of b blocks of size k. Traditionally, the construction of A-optimal block designs for such situations has been carried out assuming a fixed effects model. In this paper, we show that A-optimal designs constructed under a fixed effects model are robust in the sense that these designs have maximal minimal efficiency when considered among all available designs and under all possible mixed effects models. AMS 1991 subject classifications: Primary 62K05; Secondary 62K10     

数据挖掘在信用风险管理中的应用

本文详细分析了在现代信用风险管理中不同方法对数据质量的要求,并在此基础上提出采用数据挖掘方法改进数据质量、提高计算精度的建议,供我国金融机构信用风险管理之借鉴。     

绿色供应链的运作模型研究

在供应链运作参考模型(SCOR模型)基础上提出绿色供应链的运作模型,并将其划分为绿色供应链的采购环节、绿色供应链的制造环节、绿色供应链的支付环节和绿色供应链的回收环节分别研究。提出了一个完整的绿色供应链的运作模型。     

高校网上招生系统的后续开发与研究

针对目前院校端网上招生录取系统存在的局限性,文章详细介绍了高校网上招生后续开发管理系统的功能,讨论了系统实现中的关键技术及实现方法,指出该系统采用分布式计算技术,建立基于组件的3层C/S模型的体系结构,具有高效性、可伸缩性、开发周期短、安全性高的特点。     

中国城市住宅市场的结构差异性分析

市场价商品房、经济适用住房和廉租房构成了目前中国城市住宅市场的供应体系.依据中国30个主要城市的房地产开发统计数据,选择吸纳率作为评价住宅市场供需均衡状态的指标,利用固定影响变截距模型,重点研究了商品房和经济适用住房供给结构的城市差异性.研究发现,在城市住宅市场中,经济适用住房市场和商品房市场具有很强的相关性.作为具有政府资助性质的经济适用住房建设,存在典型的地域性特征,其政策的设定和实施会对整个住宅市场产生影响,地方政府应在利用比较全面的住宅市场指标体系进行综合分析基础上,制定适合本地的经济适用住房政策.     

窄岭金矿剪切带基本特征与发展演化模式

河北丰宁窄岭金矿,可以区分3幕Ⅰ级韧性剪切带,1幕Ⅱ级脆韧性剪切带和1幕Ⅲ级脆性剪切带。伴随不同的剪切变形变质作用,分别有花岗岩(红旗菅子群花岗片麻岩)→闪长岩(变闪长岩)→正长斑岩→含金石英脉的侵位。而金矿则是这种多期多阶段构造—岩浆复杂演化使金逐步富集的最终产物。     

消费者与组织购买行为的比较研究

消费者购买行为是消费者为满足个人或家庭生活需要而发生的购买商品的决策或行动，组织购买行为是组织与组织之间的营销活动。组织购买与消费者购买有着较大的差异，因规模远比后者大而对市场经济的作用巨大，在市场营销理论中也占看重要的地位。对消费者与组织购买行为进行比较研究，对组织购买决策模型加以对比分析，有助于更好地理解组织购买活动与购买决策过程。