K331热采封隔器一体管采油技术在曙光油田的应用

针对超稠油热采周期短、作业频繁以及作业成本高等问题,研制了大直径重复坐封K331热采封隔器.它与保温热采一体管及杆式泵结合,实现了热采一次性管柱采油.与常规热采技术相比,在充分保证热采效果的基础上,超稠油油井应用该项技术可以达到提高生产时率、降低作业成本的目的.     

CO2三元复合辅助蒸汽吞吐技术在曙光油田的应用

CO2三元复合辅助吞吐复合采油技术是针对稠油蒸汽吞吐采取的一种增产措施.该项技术是CO2吞吐技术与化学吞吐、化学解堵、气举助排相结合的复合性增产措施.该技术综合考虑了CO2和表面活性剂对油层的共同作用,克服了单纯注CO2易造成无机及有机结垢和胶质、沥青质结块而堵塞油层的不足,对油层具有储能、增温、解堵及负压掏空的多重作用,是近年发展起来的一种提高采收率的新方法.     

改性脲醛树脂防砂技术的应用

针对辽河油区科尔沁油田部分油井出砂情况,对改性脲醛树脂防砂技术原理进行了细致分析,认为改性脲醛树脂性能稳定,固砂效果好,施工简便,能有效减缓地层出砂速度.该技术在科尔沁油田现场试验,取得了很好的防砂效果.     

曙三区综合防砂研究与应用

通过对曙三区砂岩油藏地质特征和出砂机理的精细研究,制定出该区各开发阶段的防砂工艺,并在此基础上从防砂机理、防砂方式等方面进行了防砂效果评价,结果证实各项防砂方案及防砂技术均适应了各个阶段的开发特点,油层潜力得以充分发挥.为国内同类油藏的开发提供了一定的实用性和可操作性.     

Large deviation asymptotics for statistical treatment rules

This note applies large deviation-based optimality theory to evaluate treatment rules for treatment assignment problems. We find nearly optimal treatment rules whose asymptotic maximum large deviation risks can be arbitrary close to the corresponding minimax bounds.     

Sun,sand and September 11: a model of tourism demand for the Maldives

Tourism is a key source of income for many small island economies, and so it is important to understand its determinants in such countries. We estimate a tourism demand model for the Maldives’ five main source markets and find that, in addition to the usual foreign income and own price variables, the cost of travel and of visiting alternative destinations (often missing from studies of this nature) almost always have a significant role. In addition, the country’s own marketing efforts prove effective at influencing demand. Finally, we find evidence the War on Terror has persistently depressed demand from some markets.     

规模化过程中钢铁企业的组织结构设计

首先,分析了我国钢铁行业发展的特点,认为产品结构不够完善、行业集中度较低以及企业规模偏小是我国钢铁企业面临的主要问题,而规模是造成上述现状的根本原因;国际钢铁业己进入由大企业集团主宰的国际市场化阶段,我国钢铁企业需要扩大规模,增加在国际竞争中的话语权。其次,围绕企业的规模运作,运用经济学模型对小规模企业生产、紧密合作型企业生产以及产业链的大规模企业生产模式进行了分析,从理论视角论证了企业扩大规模的动机以及规模优势产生的机理和所需条件。大型组织结构优势产生的机理在于,通过生产及运营要素的优化整合实现合理分工协作,从而降低运营成本,提高企业的竞争力。此外,对钢铁企业采用的组织结构特点和运营模式进行了探讨,一元式的组织结构能够发挥职能分工所带来的效率,然而高度的集权特征不适用于超大规模企业的管理决策。控股公司和事业部结构体现了规模化后组织结构由集权向分权转化的趋势,但在运行中面临的效率障碍在于无法消除部门机会主义,分权后权威统筹机构的缺位以及传统的规模企业应当分权的逻辑需要企业重新思考。在上述分析基础上提出,钢铁企业在实现形式上的规模化后,需要考虑技术任务特征、信息处理以及权力的分化整合的平衡,构造合理的控制机制以保证规模优势的实现。     

Large Stakes and Big Mistakes

Workers in a wide variety of jobs are paid based on performance, which is commonly seen as enhancing effort and productivity relative to non-contingent pay schemes. However, psychological research suggests that excessive rewards can, in some cases, result in a decline in performance. To test whether very high monetary rewards can decrease performance, we conducted a set of experiments in the U.S. and in India in which subjects worked on different tasks and received performance-contingent payments that varied in amount from small to very large relative to their typical levels of pay. With some important exceptions, very high reward levels had a detrimental effect on performance.     

大中型企业会计凭证管理方法亟待创新

目前会计凭证的形式和管理制度在财务信息化和网络化的背景下,存在诸多问题,已不能适应信息时代对会计信息的要求。主要表现为：网络的远程办公,导致凭证的签名问题很难解决,存在较多的财务制度漏洞;目前的凭证的管理手段落后,大量编订的凭证不利于检索、事后监督和管理;此外凭证信息和业务信息不够充分,导致业务和财务信息的关联性不强,无法快速获取企业的业务信息,对企业财务的管理和审计提升存在巨大的障碍。本文从大中型企业的财务管理实践出发,通过对以上的问题的探讨,提供了具有实践操作性的解决方案和建议,对当前大中型企业的网络化财务管理提升具有一定的指导作用。     

大企业病：“丰田召回”的深层次原因

丰田召回事件还在发展中,而究其深层次原因,是由＂大企业病＂所导致的一系列管理病症的一次总爆发。丰田召回事件,也给中国汽车制造企业和其他企业提出了重要警示。企业经营不仅要考虑规模扩张,更要考虑持续发展。     

Principal Component Models for Generating Large GARCH Covariance Matrices

The implementation of multivariate GARCH models in more than a few dimensions is extremely difficult: because the model has many parameters, the likelihood function becomes very flat, and consequently the optimization of the likelihood becomes practicably impossible. There is simply no way that full multivariate GARCH models can be used to estimate directly the very large covariance matrices that are required to net all the risks in a large trading book. This paper begins by describing the principal component GARCH or 'orthogonal GARCH' (O-GARCH) model for generating large GARCH covariance matrices that was first introduced in Alexander and Chibumba (1996) and subsequently developed in Alexander (2000, 2001b). The O-GARCH model is an accurate and efficient method for generating large covariance matrices that only requires the estimation of univariate GARCH models. Hence, it has many practical advantages, for example in value–at–risk models. It works best in highly correlated systems, such as term structures. The purpose of this paper is to show that, if sufficient care is taken with the initial calibration of the model, equities and foreign exchange rates can also be included in one large covariance matrix. Simple conditions for the final covariance matrix to be positive semi-definite are derived.
(J.E.L.: C32, C53, G19, G21, G28).     

Large deviations and multinomial probit choice

We consider a discrete choice model in which the payoffs to each of an agent?s n actions are subjected to the average of m i.i.d. shocks, and use tools from large deviations theory to characterize the rate of decay of the probability of choosing a given suboptimal action as m approaches infinity. Our model includes the multinomial probit model of Myatt and Wallace (2003) [5] as a special case. We show that their formula describing the rates of decay of choice probabilities is incorrect, provide the correct formula, and use our large deviations analysis to provide intuition for the difference between the two.