差

If we have omitted important factors that are correlated with the explanatory variables, then the coefficient estimates are not reliable: OLS is biased.

如果存在严重的缺省变量问题，那么OLS估计就是有偏的；如果存在异方差，那么标准误就不能用于估计标准差，因而在这些问题下构造出的置信区间并不是真正的95％CI。

The results showed that the UV254 and organic index have a certain special correlation curve in a river with steady water quality, and the correlation between the UV254 and the organic index is higher in a river with worse water quality than in a river with better water quality.

结果表明：在特定的、水质较稳定的河流中，UV254与有机指标有特定的相关曲线，水质差的河流中两者相关性高于水质较好的河流；在分布较广、水体特征不一的湖泊水库中其相关性较差。

This paper discusses one classification method of differential protection based on the correspondence between the principle and variable of the generalized differentiation method .

基于广义求差法的原理和变量对应关系，探讨了差动保护的一种分类方法。

Third, the discussion of the corresponding relationship of the real angles to the apparent real angles is performed, the asymptotic bias and MSE of real angles are given. Fourth, based on above conclusions, the analysis of two typical cases is made by numerical analysis and computer simulation: Case A when the impinging signals are divided into desired signals and interfering signals: it is shown that similar to Cyclic estimation of DOA, the smaller the separation between interfering direction and signal direction, in general, the smaller the estimation variance.

首先，研究了无穷快拍时信号数目有误的最大似然估计，引入了视在真实角度的概念；其次，导出了视在真实角度最大似然估计大样本时的分布以及渐近均方误差的解析表达式，而且还证明了：Stoica性能分析结果是现在的分析结果在信号数目准确时的特例；第三，讨论了真实角度与视在真实角度的关系，给出了真实角度的渐近偏和渐近均方误差；第四，依据前面的结果，利用数值分析和模拟实验的方法对两种典型情况做了分析： 1 在入射信号被分为干扰信号和所需信号情况下：结果表明：与CyclicDOA估计一样，干扰方向与所需信号方向靠的越近，所需信号估计的方差越小，越远离，方差越大。

The main environment geological question is: The earth"s crust where the faultage and earthquake are active is unstable; collapse , landslide, mud-rock flow and soil erosion ; The underground karst subsides, seepage question; Basic rock expand, expend and compress soil body, the salt deposit corrode out of shape and groundwater"s corrodent harm; The soft soil question of basin; The soft rock body, cracked rock and the weathering rock are relatively poor stability; High and cold regional highways and railways" frozen soils freeze and melt calamity problem; The around rock of tunnel are unstable because of the coal seam gas, spring water, underground developed area; Project cutting slopes, constructed abandon soil and reservoir, lake"s ecology geological environmental protection issue; Thedangerous shoal of the channel % submerged reef question; The problem of rebuilding channel project and dock etc.; And the problem of unstable ground and groundwater corrosivity during building airport; At the same time, with the international big pathways" implementation and completions of constructions, adjusting the cities and counties" constructions , the crowd occupy changing , the cultivated land distribute changing and the adjustments of structure, will cause local environmental geological issues outstanding; According to multiple statistical analysis , value calculate and integrated appraise result, in the northwest and southwest of Yunnan, the traffic relatively low density, traffic engineering is relatively weak impact on environment, It is the area where a environme

主要的环境地质问题是：活动性断裂、地震带的地壳不稳定；崩塌、滑坡、泥石流及水土流失；地下岩溶塌陷、渗漏问题；基础岩体膨胀、胀缩土体、含盐层侵蚀变形和地下水的腐蚀危害；盆地软土问题；软弱岩体、碎裂、风化岩体稳定性较差；高寒地带公路、铁路建设的冻土冻融灾害问题；煤层瓦斯、涌水、地下采空区等隧道围岩不稳定问题；工程切坡、施工弃土及水库、湖泊生态地质环境保护问题；航道险滩、暗礁问题；渠化工程、码头等库岸再造问题；以及机场建设中的不稳定地基及地下水腐蚀性问题；同时，随着大通道建设的实施和完成，城镇建设的调整、人群居落的变化和耕地分布及结构的调整组合，都可能造成局部环境地质问题的突出等等。经多元统计分析数值计算、综合评价结果，滇西北、滇西南地区交通密度较低，交通工程对环境的影响程度较弱，是环境地质状况好的区域；有主要高原湖泊分布区的，包括昆明、个旧、文山的滇东南区域，环境地质状况较好；大姚、楚雄、篙明及会泽、昭通一镇雄的区域，即滇中北部中生界红层和滇东北岩溶区，环境地质状况中等；而包括保山、德宏、大理、临沧的滇西地区及景东一墨江以东、双柏一石屏一河口以西及东川一寻甸一曲靖地段的滇中一滇东地区，环境地质状况较差。云南国际大通道建设涉及全省区域，如何利用地质环境、实现可持续发展，就必须依赖于国际大通道建设与地质环境之间良性关系的建立。应本着对区域地质环境客观存在的科学认识原则、建设过程中环境效益优先的可持续发展原则、法制性原则、对大通道建设中环境地质的因地制宜及其可防治性原则。并且从组织管理、不同类型大通道、不同环境地质问题类型等方面，提出了对策措施。最后，提出了建立国际大通道建设与环境地质良性关系的宏观建议。

Permanent corvee tax was registered and there were also temporary additional corvee taxes.

籍'。''的永久性差税，还有临时加派的差税。

We transformed eccentric coaxial line cross-section into rectangular area by hyperbolic cotangent transformation, transformed the FDTD difference expressions into CM-FDTD difference formula, calculated the cutoff wavenumbers of higher order TE and TM modes in eccentric coaxial line.

本文用双曲余切变换将偏心同轴线截面变换为矩形区域，相应地将FDTD差分格式变换为保角变换FDTD差分格式，计算了偏心同轴线TE、TM高阶模的截止波长。

Windows evaluation algorithm based on covariance function was proposed to evaluate the measure variance of electronic compass and micromechanical gyroscope.

提出了基于协方差函数的加窗估计算法，用于在线估计电子罗盘和微机械陀螺的测量方差。

We show the different properties between covariance risk allocation function and relative risk allocation function and prove that the commonly used risk budgeting model is a special form of risk allocation function.

我们证明并比较了在标准差风险度量下，协方差风险分配函数与相对风险分配函数性质上的差异，并证明风险预算也是一种特殊形式的风险分配函数。

Considering that the covariance function could not exist in some conditions, we put forward the idea of using the variogram function as a substitute for the covariance function and prove their equivalence.

考虑到在某些情况下协方差函数可能不存在，因此考虑用变异函数来代替协方差函数估计径向基核函数的宽度参数。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。