深井水平井水平段水力延伸能力评价与分析

对影响水平井水平段延伸能力的因素进行了分析,然后根据钻井液流体力学理论,建立了水平井循环压耗计算模型,分别对水平井总循环压耗和水平段环空压耗进行计算,进而求出了水平井水平段极限延伸长度值;对钻井液密度、钻井泵额定压力、岩屑床高度和钻井液排量对水平段水力延伸能力的影响进行了分析。研究表明,水平段水力延伸能力受钻井液密度、钻井泵额定压力、岩屑床高度和钻井液排量等多个因素共同影响。为了提高深井水平井的延伸能力,应使用较低密度的钻井液;尽量保持较低的岩屑床高度;钻井液排量应尽量小。同时还认识到,深井水平井水力延伸能力主要受到钻井泵额定压力的制约。研发高额定压力的钻井泵,是提高深井水平井水力延伸能力的主要措施。     

多孔介质内流体相态特征超声波探测研究进展

目前有关烃类流体相态的研究已较为成熟,能为油气田的高效开发提供相应的理论指导和技术支持。但研究成果大多忽略多孔介质对流体相态的影响。为此,在充分考虑流体与多孔介质相互作用的基础上,开展多孔介质内流体相态特征的研究十分必要。随着研究的不断深入,超声波探测技术不受压力温度限制、不改变流体成分、检测成本低、对人体无害等优点逐渐得到重视,并在多孔介质内相态研究领域逐渐得到了应用。在参考国内外相关文献资料的基础上,简述了超声波的探测机理,重点综述了超声波探测在多孔介质内天然气水合物、凝析油气相态特征研究的应用进展,并指出了目前存在的主要问题及今后的研究重点。     

Complete consistency for the estimator of nonparametric regression models based on extended negatively dependent errors

In this paper, we provide some exponential inequalities for extended negatively dependent (END) random variables. By using these exponential inequalities and the truncated method, we investigate the complete consistency for the estimator of nonparametric regression model based on END errors. As an application, the complete consistency for the nearest neighbour estimator is obtained.     

供应商参与、专用性投资与新产品开发绩效关系研究

本文构建了一个供应商参与、专用性投资与制造商新产品开发绩效的理论模型。以往的实证研究大多将专用性投资视作供应商参与的解释变量,本文认为专用性投资是供应商同制造商合作过程中逐步累积形成的互补性资产,提出供应商参与对专用性投资有正向影响的研究假设。实证研究结果发现,供应商能力、制造商对供应商的信任对供应商参与有显著正向影响,制造商对供应商的控制能力、供应商参与对专用性投资有显著正向影响,供应商参与、专用性投资对制造商的新产品开发绩效有显著正向影响。     

Monitoring Change in Persistence Against the Null of Difference-Stationarity in Infinite Variance Observations

In this article, we propose a moving kernel-weighted variance ratio statistic to monitor persistence change in infinite variance observations. We focus on I(1) to I(0) persistence change for sequences in the domain of attraction of a stable law and local-to-finite variance sequences. The null distribution of the monitoring statistic and its consistency are proved. In particular, a bootstrap procedure is proposed to determine the critical values for the derived asymptotic distribution depends on unknown tail index. The small sample performances of proposed monitoring procedure are illustrated by both simulation and application to a high frequency financial data.     

A Parametric Bootstrap Test for Two-Way ANOVA Model Without Interaction Under Heteroscedasticity

In this article we consider the two-way ANOVA model without interaction under heteroscedasticity. For the problem of testing equal effects of factors, we propose a parametric bootstrap (PB) approach and compare it with existing the generalized F (GF) test. The Type I error rates and powers of the tests are evaluated using Monte Carlo simulation. Our studies show that the PB test performs better than the GF test. The PB test performs very satisfactorily even for small samples while the GF test exhibits poor Type I error properties when the number of factorial combinations or treatments goes up. It is also noted that the same tests can be used to test the significance of random effect variance component in a two-way mixed-effects model under unequal error variances.     

Private Labels: Facilitators or Impediments to Supply Chain Coordination

We consider a retailer’s decision of whether to develop an internally produced, private label version of a national brand and the role that this decision plays in coordinating the supply chain. Our model assumes that the perceived quality of the private label is lower than that of the national brand, and we allow for the two products to have different marginal costs. We further allow for a fixed development cost that the retailer must incur to develop private label capability, and distinguish two types of private labels depending upon whether they would or would not be developed as product line extensions by a vertically integrated supply chain. We refer to these two types as first‐best (FB) and non‐first‐best (NFB) product line extensions, respectively. When the private label can be characterized as a NFB product line extension, its development creates adverse cannibalization effects, yet it also helps to mitigate the effects of double marginalization with respect to the national brand. We characterize the conditions under which the retailer will develop private label capability, and distinguish among the conditions under which this is either beneficial or detrimental to the overall performance of the supply chain.