电场作用下裂缝介质单相渗流数值模拟

1.China University of Petroleum:a.School of Physics Science and Technology,b.College of Petroleum Engineering,Dongying Shandong 257061,China；2.Luning Transmit Oil Section,Pipeline Storage & Transportation Company,SINOPEC,Zoucheng Shandong 273500,China)JOURNAL OF SOUTHWEST PETROLEUM UNIVERSITY(SCIENCE & TECHNOLOGY EDITION)，VOL.31，NO.6,85-88,2009（ISSN 1674-5086，in Chinese     

An Empirical Comparison of Estimating Methods for the Ramberg–Osgood EIV Model

The standard tensile test is one of the most frequent tools performed for the evaluation of mechanical properties of metals. An empirical model proposed by Ramberg and Osgood fits the tensile test data using a nonlinear model for the strain in terms of the stress. It is an Error-In-Variables (EIV) model because of the uncertainty affecting both strain and stress measurement instruments. The SIMEX, a simulation-based method for the estimation of model parameters, is powerful in order to reduce bias due to the measurement error in EIV models. The plan of this article is the following. In Sec. 2, we introduce the Ramberg–Osgood model and another reparametrization according to different assumptions on the independent variable. In Sec. 3, there is a summary of SIMEX method for the case at hand. Section 4 is a comparison between SIMEX and others estimating methods in order to highlight the peculiarities of the different approaches. In the last section, there are some concluding remarks.     

ADAPTING THE MODEL: THERAPEUTIC WORK WITH CHILDREN FROM ARMY FAMILIES

This paper describes the development of a specialised therapeutic service for parents and their young children in an inner city social services family centre. The Under five's counselling service, based on the Tavistock Model, offers brief psychoanalytic interventions to parents who are worried about their young child's development e.g. crying, eating, persistent crying etc. The premise behind setting up such a service was to provide therapeutic intervention to the parent-child relationship at the earliest possible stage, preventing further ongoing difficulties. The paper draws upon observations and interventions with families I have seen in the first year the service was opened. Particular themes which emerged in the work with these families will be highlighted. In particular a link is made between early childhood difficulties and unresolved loss in the mother's lives. Furthermore, the impact of the service upon the rest of the social services family support services is commented upon.     

欧洲主权债务危机与欧元的前景

由美国次贷危机引发的全球性金融危机对欧洲大陆的冲击使欧洲长期积累的财政和债务问题逐步转变为主权债务危机。欧债危机的持续发酵主要是由欧元区内货币政策与财政政策脱节、高社会福利与低经济增长矛盾以及危机爆发后救助迟缓、乏力等因素导致的,同时它也是欧元区在建立之初就一直存在的严重的结构性缺陷所带来危害的集中体现。欧债危机对欧元区的稳定造成了极大冲击,给欧元未来的命运蒙上了一层阴影。欧元区未来的结局可能是促使欧债危机国家退出欧元区,而这对欧洲一体化进程则是沉重的打击。     

Assessing participants’ perceptions on group-based principles for action in community-based health enhancing physical activity programmes: The APEF tool

In community-based health enhancing physical activity (CBHEPA) programmes, group-based principles for action such as active participation, enjoyment, and fostering group processes are widely advocated. However, not much is known about participants’ perceptions of these principles as there are no assessment tools available. Therefore, this article describes the development of the APEF (Active Participation, Enjoyment, and Fostering group processes) tool and reports on its implementation in a Dutch CBHEPA programme. Indicators for the principles have been identified from literature research, interviews with professionals, and secondary analysis of three group interviews with 11 practitioners. To address the identified indicators, the APEF tool was developed, pretested, and used in 10 focus groups with 76 participants.The APEF tool consists of eight statements about group-based principles for action, on which CBHEPA participants vote, followed by in-depth discussion. The voting procedure engages participants. Spider diagrams visualise participants’ perceptions of group-based principles.The APEF tool addresses the challenge of relating group level outcomes to individual outcomes such as physical activity behaviour. The tool facilitates as well as evaluates group-based principles for action, it stimulates dialogue and is culturally sensitive, but it needs strong facilitating skills to manage group dynamics.     

Estimating consumer acceptance limits

A methodology is developed for estimating consumer acceptance limits on a sensory attribute of a manufactured product. In concept these limits are analogous to engineering tolerances. The method is based on a generalization of Stevens' Power Law. This generalized law is expressed as a nonlinear statistical model. Instead of restricting the analysis to this particular case, a strategy is discussed for evaluating nonlinear models in general since scientific models are frequently of nonlinear form. The strategy focuses on understanding the geometrical contrasts between linear and nonlinear model estimation and assessing the bias in estimation and the departures from a Gaussian sampling distribution. Computer simulation is employed to examine the behavior of nonlinear least squares estimation. In addition to the usual Gaussian assumption, a bootstrap sample reuse procedure and a general triangular distribution are introduced for evaluating the effects of a non-Gaussian or asymmetrical error structure. Recommendations are given for further model analysis based on the simulation results. In the case of a model for which estimation bias is not a serious issue, estimating functions of the model are considered. Application of these functions to the generalization of Stevens’ Power Law leads to a means for defining and estimating consumer acceptance limits, The statistical form of the law and the model evaluation strategy are applied to consumer research data. Estimation of consumer acceptance limits is illustrated and discussed.     

The typification of Hispanics as criminals and support for punitive crime control policies

The Hispanic population is now the largest and fastest growing minority in the United States, so it is not surprising that ethnic threat linked to Hispanics has been associated with harsher crime control. While minority threat research has found that individuals who associate blacks with crime are more likely to support harsh criminal policies, the possibility that this relationship exists for those who typify Hispanics as criminal has yet to be examined. Using a national random sample, this study is the first to use HLM to find that perceptions of Hispanics as criminals do increase support for punitive crime control measures, controlling for various individual and state influences. Moderated and contextual analyses indicate this relationship is most applicable for individuals who are less apt to typify criminals as black, less prejudiced, less fearful of victimization, politically liberal or moderate, not parents, and living in states with relatively fewer Latin American immigrants.     

C2C卖家的诚信行为模式及其动态性研究

现有电子商务的信用评价体系单一维度的特点使得评级体系难以准确衡量、比较店铺在各维度之间的差异及其变化。为了提高C2C电子商务信用评级体系的信息揭示作用,本文试图从多维度指标分析店铺的诚信行为模式及其动态性。本文对淘宝7大行业不同信用等级的卖家的诚信指标数据进行聚类分析表明,店铺在动态评分、信用等级、好评率上分别具有六类不同的静态组合特征,信用积分在解释店铺诚信状态上弱于动态评分和好评率指标。动态模式分析表明,店铺的好评率、动态评分指标及其与同业行业比值会呈现出三个不同的组合变化趋势。最后本文提出对现有的评价体系改进,以体现店铺之间在模式上的差异,从而真实展现卖家的诚信水平。     

气体钻与泥浆钻全井段钻柱动力学对比研究

全井段钻柱在井内运动过程是一个非常复杂的非线性动力学问题，不可能得到比较完美的解析解，如果采用室内试验或者现场试验研究，其成本又会很高且很难实现。因此，在弹塑性力学、岩石力学和钻柱力学的基础上，以四川某井基本钻井参数和钻具组合为依据，采用有限元法建立了塔式钻具钻至1486m井深时的全井段三维钻柱模型和相应的井筒模型，并且建立了钻头与岩石以及钻柱与井筒之间的随时间变化且有摩擦系数的接触关系和相对应的泥浆钻井模型，对比分析了钻柱在动态钻进过程中的井口参数、钻头上压力和转动速度以及全井段钻柱的弯矩扭矩变化等结果，得出气体钻井与泥浆钻井全井段钻柱的运动规律以及钻铤失效机理的差异。为认识气体钻井全井段钻柱的运动规律提供了新的研究方法，对气体钻井中钻柱力学、井斜控制和设备等方面的研究都有较好的现实意义。     

Nonlinear and non-gaussian state estimation: A quasi-optimal estimator

The rejection sampling filter and smoother, proposed by Tanizaki (1996, 1999), Tanizaki and Mariano (1998) and Hiirzeler and Kiinsch (1998), take a lot of time computationally. The Markov chain Monte Carlo smoother, developed by Carlin, Poison and StofFer (1992), Carter and Kohn (1994, 1996) and Geweke and Tanizaki (1999a, 1999b), does not show a good performance depending on noniinearity and nonnormality of the system in the sense of the root mean square error criterion, which reason comes from slow convergence of the Gibbs sampler. Taking into account these problems, we propose the nonlinear and non-Gaussian filter and smoother which have much less computational burden and give us relatively better state estimates, although the proposed estimator does not yield the optimal state estimates in the sense of the minimum mean square error. The proposed filter and smoother are called the quasi-optimal filter and quasi-optimal smoother in this paper. Finally, through some Monte Carlo studies, the quasi-optimal filter and smoother are compared with the rejection sampling procedure and the Markov chain Monte Carlo procedure.