NA样本分布估计的一致强相合性

在NA相依样本下,研究经验分布函数估计和分布密度核估计的一致强相合性,获得了与独立情形一致的结论。     

黑白两色 重1.2千克 爱普生推出轻薄本

日本的爱普生推出了新款的笔记本电脑，型号为Endeavor NA101，爱普生公司表示将在7月上旬开始正式接受BTO定制。新推出的Endeavor NA101笔记本重量只有1.2千克，主要定位于移动便携类产品，Endeavor NA101的承重能力达到了150千克。     

NA相依样本的非参数核估计

假设非参数衰退模型Yi=g(Xi)+iε,其中残差{iε}是一个具有未知公共密度函数f(x)的NA相依样本,g(x)=E(Y+X=x)是未知衰退函数.今首先在残差基础上定义了非参数估计gn(x)和^fn(x),并在适当条件下证明了gn(x)和^fn(x)分别是g(x)和f(x)的强一致相合估计,同时给出了相应的收敛速度.     

NA列的随机足标和与首达时的完全收敛性

通过讨论NA列非随机足标和的完全收敛性的一系列等价条件，本文得到了NA列随机足标和的完全收敛性结果。并借以讨论“首选时”的完全收敛性．将Gut(1983)的结果从iid列的场合推广到更广泛的同分布NA列的场合．     

行为两两NQD阵列加权和的矩完全收敛性

负相依在统计分析和可靠性理论中有着广泛地应用。本文的目的是要研究行为两两负象限相依阵列加权和的矩完全收敛性。利用矩不等式和截尾方法,建立了行为两两负象限相依阵列加权和的矩完全收敛性的充分条件,同时给出了具体应用,获得了基于负象限相依序列的平滑移动过程的矩完全收敛性,推广并完善了以前的结果。     

m相依样本均值随机加权估计的渐近性质

本文利用基于刀切虚拟值的随机加权法，解决了ｍ相依样本均值随机加权逼近的相合性问题。     

相依随机变量列的极限定理

相依随机变量列是否有大数定律是可靠性理论和管理科学中经常遇到的问题。本文讨论了相依随机变量列的极限定理,获得了渐近负相关随机变量列的大数律,且伯恩斯坦大数律可作为本文结果的特例。特别是,获得了Loéve定理的一个等价形式,并讨论了相依随机变量列部分和上升的阶。     

半相依回归系统的岭型主成分改进估计

对于一类半相依回归系统，本文提出了一种岭型主成分改进估计，并讨论了这种估计及相应的两步估计的优良性质，获得了若干深入的结果。     

LP-15聚酰亚胺树脂的增韧研究

采用自行合成的分子两端、 一端带有NA端基和两端都不带NA端基的三种齐聚物, 以及化学组成相同、 分子链长不同的齐聚物和高聚物通过物理共混法对LP-15树脂进行增韧。比较了齐聚物的端基结构、 分子量大小对LP-15树脂耐热性、 冲击强度的影响, 讨论了其增韧机理。结果表明: 所有增韧体系中增韧剂与LP-15间均具有很好的相容性, 且保持了LP-15树脂原有良好的耐热性。但分子带NA端基与不带NA端基的齐聚物相比, 后者的增韧效果更好; 当分子两端均不带NA端基时, 分子链长的高聚物的增韧效果优于分子链短的齐聚物。     

基于β-混合序列的学习机器的相对一致收敛速率的界

推广性能是机器学习理论研究的主要目的之一。为了研究相依序列下采用ERM算法的学习机器的推广性能,本文基于β-混合序列建立了采用ERM算法的学习机器的经验风险到它的期望风险相对一致收敛速率的界。这个界不仅把基于独立序列下已有的结果推广到β-混合相依序列的情况,而且对β-混合相依序列现有的一些结论进行了改进。得到了β-混合相依序列下,采用ERM算法的学习机器的推广性能的界。     

Negative piezoresistivity in continuous carbon fiber epoxy-matrix composite

The negative and positive piezoresistivity in continuous carbon fiber epoxy-matrix composite has been clarified. The negative piezoresistivity associated with the increase of the through-thickness resistivity upon longitudinal tension and decrease in the through-thickness resistivity upon longitudinal compression is practically attractive for strain sensing and is attributed to the decrease in the degree of contact between fibers of adjacent laminae upon longitudinal tension. This effect is stronger, more reversible and less prone to causing minor damage for the tension case than the compression case. The positive piezoresistivity associated with the longitudinal resistivity increasing upon longitudinal tension is negligibly weak, if any, independent of the number of laminae. The previously reported negative piezoresistivity associated with the longitudinal resistivity decreasing upon longitudinal tension does not occur for a commercially manufactured composite in which the fibers are well aligned.     

Driving under the influence of cannabis: Links with dangerous driving, psychological predictors, and accident involvement

Driving under the influence of cannabis (DUIC) has become a growing concern. Studies investigating the impact of DUIC on traffic safety have shown evidence that, during the acute period of cannabis intoxication, cannabis diminishes driving faculties and is associated with an elevated risk of collision. However, DUIC drivers seem to exhibit a general reckless driving style that may contribute to an over-estimation of DUIC-related collisions among this group. In this study, we investigated DUIC drivers with respect to self-reported dangerous driving habits (e.g., risky driving, aggressive driving and negative emotional driving), behaviours observed in a driving simulator, psychological predictors and crash involvement. Results suggest that DUIC is associated with self-reported and observed risky driving and negative emotional driving. We also found that sensation seeking and impulsivity are independent psychological predictors of DUIC. Finally, a trend suggests that self-reported DUIC is associated with an increased risk of being involved in a car accident, after controlling for dangerous driving and demographic variables. Implications for interventions are discussed.     

Construction of deformed photon-added nonlinear coherent states with negative m for the one-mode field in a Kerr medium

In this paper, based on the nonlinear coherent states formalism and using the Hamiltonian for a single mode field in a Kerr medium, the deformed photon-added nonlinear coherent states with negative m corresponding to the nonharmonic oscillators are constructed. In addition, some of the nonclassical properties associated with these states such as the Mandel parameter, quadrature squeezing and second-order correlation function are investigated. It is found that the deformed photon-added nonlinear coherent states with negative m for the one-mode field in a Kerr medium are nonclassical states.     

Picosecond Pulse Measurement of the Conduction Current versus Voltage Characteristics of Semiconductor Materials with Bulk Negative Differential Conductivity

Semiconductors that show current instabilities usually have an associated negative conductivity for a certain range of electric field. Information about this region may be obtained from direct two-terminal measurements on the material. A direct method of measurement is described in which a voltage pulse, in the form of a fast-rising ramp, is applied to the sample and the current waveform is simultaneously observed. Also described are techniques for generating suitable driving waveforms, and for measuring and separating the conduction and displacement current components. The method has been used for measuring the characteristics of materials with values of negative dielectric relaxation time in the -50-picosecond region.     

The resistivity of the β-W compounds

The very marked negative curvature in the resistance characteristics of superconducting β-W type compounds, such as Nb₃Sn, has traditionally been associated with the existence of a very sharp peak in the electronic density of states at the Fermi level, but this explanation has been challenged recently by several authors. In this work the Bloch-Mott-Wilson model for the resistivity of transition metals is modified to account for the negative curvature and the more limited variation of resistance observed for less ideal samples. It is assumed that conduction by d-electrons is generally significant. The rate of scattering of d-electrons by phonons is shown to be reduced when the mean free path of the d-electrons is very short, thus limiting the intrinsic resistivity when the total resistance is rather high. Plausible agreement is demonstrated between the corresponding expression for the resistivity and the published data.     

Quantum Nucleation of Bubbles from Electrons in Liquid Helium at Negative Pressure

We consider the quantum, nucleation of bubbles associated with negative ions in liquid helium at negative pressure.     

The occurrence of negative added mass in free-surface problems involving submerged oscillating bodies

Summary The phenomenon of negative added mass is studied by considering the heave oscillations of a submerged vertical cylinder. Free-surface effects are shown to be important for the occurrence of negative added mass. Rapid changes in the added mass and damping, as functions of frequency of oscillation, often associated with this phenomenon are explained in terms of near-resonant standing waves above the body.     

The effect of infrastructure and demographic change on traffic-related fatalities and crashes: a case study of Illinois county-level data

This paper presents analyses of data from the Highway Safety Information System (HSIS) for the State of Illinois. Our analyses focuses on whether various changes in road network infrastructure and geometric design can be associated with changes in road fatalities and reported accidents. We also evaluate models that control for demographic changes. County-level time-series data is used and fixed effect negative binomial models are estimated. Results cannot confirm the hypothesis that changes in road infrastructure and geometric design have been beneficial for safety. Increases in the number of lanes appears to be associated with both increased traffic-related accidents and fatalities. Increased lane widths appears to be associated with increased fatalities. Increases in outside shoulder width appear to be associated with a decrease in accidents. Inclusion of demographic results does not significantly change these results but does capture much of the residual time trend in the models. Potentially mis-leading results are found when the time trend is not included. In this case a negative association between vertical curvature and both accidents and fatalities. No statistical association with changes in safety is found for median widths, inside shoulder widths, and horizontal and vertical curvature.     

A longitudinal study of the impact of market requirements focus on manufacturing performance

This paper examines the longitudinal relationship between market requirements focus and manufacturing performance in a sample of automotive supplier plants. Statistical analysis indicates that, overall, an increase in market requirements focus from 1995 to 1999 was associated with an increase in manufacturing performance over the same time period, while a decrease in focus was associated with decreasing performance. Furthermore, plant manager interviews suggest that plant-level involvement and firm resource commitment may serve to leverage focus improvement efforts, or moderate the negative effects of decreasing focus.