套管抗挤强度分析及计算

为提高套管挤毁压力预测精度，应用统计方法对213根套管全尺寸挤毁试验数据进行了方差分析，研究了外径不圆度、壁厚不均度、残余应力等因素对套管抗挤强度的影响。分析结果表明，径厚比、屈服强度是套管抗挤强度的主要因素，不圆度、壁厚不均度、残余应力等因素对套管抗挤强度的影响呈随机性分布。利用有限元方法对外径不圆度、壁厚不均度和残余应力的不同位置组合进行了模拟分析。结果表明，数值相同的外径不圆度、壁厚不均度及平均残余应力组合不同时，套管的挤毁压力相差很大。最后提出了一个套管抗挤强度计算公式，计算简单，精度可满足工程要求。     

中国企业出口与生产率关系实证研究——对制造业企业自我选择效应和出口中学效应的分析

运用2005—2008年中国14个制造业企业面板数据,分析企业出口的自我选择效应和出口中学效应,结果表明:中国制造业企业出口与生产率的关系违背异质性企业贸易模型,自我选择效应不显著,并且存在"生产率悖论";出口中学效应也不显著。虽然出口企业的生产率与出口规模正相关,但在控制其他影响出口规模的变量后,生产率与出口规模则呈现负相关;在控制其他影响生产率的变量后,出口规模与生产率同样也会呈现负相关。中国企业出口的自我选择效应不显著的原因在于其加工贸易等现实条件与经典理论假设的背离;而中国企业出口中学效应不明显的重要原因则在于其自我选择效应的不显著和规模报酬递减。     

Estimating with percentile grouped and truncated date from a scale parameter distribution

Data which is grouped and truncated is considered. We are given numbers n₁<…<n_k=n and we observe X_ni ),i=1,…k, and the tottal number of observations available (N> n_k is unknown. If the underlying distribution has one unknown parameter θ which enters as a scale parameter, we examine the form of the equations for both conditional, unconditional and modified maximum likelihood estimators of θ and N and examine when these estimators will be finite, and unique. We also develop expressions for asymptotic bias and search for modified estimators which minimize the maximum asymptotic bias. These results are specialized tG the zxponential distribution. Methods of computing the solutions to the likelihood equatims are also discussed.     

Combined estimate of a location parameter

In this paper, we revisit the problem of combining estimates of location considered by Cohen (1976). Our results unify and strengthen the results of Cohen (1976), Bhattacharya (1981) and Akai (1982).     

Equivariant prediction in finite populations

A theory of equivariant prediction is developed for predicting the population total in finite populations. Minimum risk equivariant predictors (MREP) are derived under the location, scale and locationscale superpopulation models. Under the general linear model, it is shown that the best(linear) unbiased predictor (B(L)UP) is an MREP.     

Clinical assessment and validation of an Arabic Aging Male Symptoms questionnaire in patients with androgen deficiency

Aim.?To develop and to validate an Arabic Aging Male Symptoms (AMS) tool and to clinically assess patients with hypoganadism after hormonal treatment.

Methods.?The tool was translated into Arabic and tested on 15 Saudi men. During a period of 9 months all males presented to the andrology clinic of the main University Hospital, King Saud University, Saudi Arabia with signs and symptoms of hypogonadism, were included in the study. Arabic AMS scale was applied in the base line visit, then 12 weeks after treatment. Testosterone was monitored before treatment, 4 weeks and after 12 weeks.

Results.?Ninety-two subjects were included, Cronbach's α of 0.91 showed a very good internal consistency of the Arabic AMS questionnaire. The corresponding α for the subscales were 0.83, 0.84 and 0.73. There was a significant improvement in the mean level of TT after hormonal therapy (HT), this was reflected on the mean differences of improvement in the total Arabic AMS scores and subscales scores after HT, ranged from 31 to 35%.

Conclusion.?The present study revealed a significant association between testosterone levels and AMS tool manifested by a its good ability to measure the effect of treatment on quality of life for patients with hypogonadism.     

治理通货膨胀预期应成为宏观政策关注的新视角

通货膨胀既可以是供求失衡导致的，也可以是货币膨胀导致的。在世界经济迅猛发展的今天，通货膨胀发生发展的机理也存悄然发生着变化，正是这些变化，使得通货膨胀对社会经济的影响已经前置到通货膨胀预期对经济发展的影响。本文以中国经济企稳过程为真实背景，初步探讨通货膨胀预期的负效应及治理的政策路径，尽管存在个案特征，但仍不失为一种分析思路。     

黔东南性别失衡人口规模的判断与预测

黔东南州作为西部欠发达省份的民族自治地区,出生性别比长期、普遍、高度的失衡已经对经济发展、社会安定造成一定影响。虽然出生性别比失衡问题得到政府和社会的广泛关注和重视,并自2004年起开展了系列治理活动,但出生性别比升高的势头并未因之而有所遏制。本文希望通过对出生性别比失衡人口规模的计算,以及预测失衡导致该州未来男女人口规模和适龄结婚人口规模差异,使人们对失衡状况与未来影响有更清晰的认识,并为进一步治理提供参考素材。     

A simulation tool for modeling the influence of anatomy on information flow using discrete integrate and fire neurons

There are theories on brain functionality that can only be tested in very large models. In this work, a simulation model appropriate for working with large number of neurons was developed, and Information Theory measuring tools were designed to monitor the flow of information in such large networks. The model’s simulator can handle up to one million neurons in its current implementation by using a discretized version of the Lapicque integrate and fire neuron instead of interacting differential equations. A modular structure facilitates the setting of parameters of the neurons, networks, time and most importantly, architectural changes. Applications of this research are demonstrated by testing architectures in terms of mutual information. We present some preliminary architectural results showing that adding a virtual analogue to white matter called “jumps” to a simple representation of cortex results in: (1) an increase in the rate of mutual information flow, corresponding to the “bias” or “priming” hypothesis; thereby giving a possible explanation of the high speed response to stimuli in complex networks. (2) An increase in the stability of response of the network; i.e. a system with “jumps” is a more reliable machine. This also has an effect on the potential speed of response.     

大型活动拥挤踩踏事故灰色层次分析

针对大型活动拥挤踩踏事故诱因复杂的特点，采用灰色层次分析法，在客观归类大型活动拥挤踩踏事故影响因素的基础上，建立拥挤踩踏事故评估灰色层次分析模型，并以沈阳世博会综合馆进行实例分析，得出安全等级，实例表明，灰色层次评估方法具备实用性，能够比较客观、真实地反映大型活动拥挤踩踏事故风险情况，值得推广和使用。