税务管理中实施抽样调查的必要性与可行性

抽样调查在税务管理中的应用是我国税务统计调查方法体系改革的需要 ,也是解决新征管模式下出现的新情况、新问题等的手段。同时 ,税务部门有较系统的抽样框、日新月异的计算设备、高素质的税务干部以及其他专业统计的抽样调查实践经验可借鉴 ,这些都为抽样调查技术在税务管理中的应用提供了现实可能性     

线性双曲型方程反问题的存在性与唯一性的探讨

本文研究了可以唯一决定未知函数组{v,（t）,v2（t）}的条件,给出了反问题的提法且论述了在L^2（0,π）中此反问题存在唯一性。     

在子集条件约束下的最大熵分布及其应用

介绍了有关熵的概念及计算方法,并将其应用于构建一类新的分布估计算法(EDAs)。该类分布估计算法用基于最大熵估计种群中的模式概率分布和从最大熵分布中抽样取代遗传算法(GA)的交叉和变异,产生新的种群。在该类算法中,二阶连接模式算法由于只使用了连接模式,在解决变量之间相互作用趋向于发生在串中相互靠近的变量之间的一类问题时,比遗传算法更好。     

矩阵双加权广义逆的Zlobec型公式

本文提出了双加权广义逆的概念,将常用的四种加权广义逆统一为一种形式,并依据加权广义逆矩阵的Zlobec型公式得到了双加权广义逆矩阵的Zlobec型公式．     

复数域上分块矩阵秩的若干等式

本文以二阶、三阶分块矩阵为例,利用Gauss初等变换和矩阵的Moore-Penrose广义逆,给出某些分块矩阵的秩与其子阵的秩之间的关系。     

高速数字存储示波器产品化设计的关键技术

论述了“100 MHz高速数字存储示波器”的关键技术,着重阐述了系统设计的概念和原理、基于低速器件的高速数据采集技术、基于随机取样技术的等效采样技术的实现。其中,随机等效采样的实现采用高分辨力测时扩展器,使等效采样率达到5 GSPS,时间测量分辨率达到200 ps,实现100 MHz(-3 dB)可重复信号的波形重现,并给出了实际应用中重建的波形图。     

Information on sexual behaviour when some data are missing

When tables contain missing values, statistical models that allow the non-response probability to be a function of the intended response have been proposed by several researchers. We investigate the properties of these methods in the context of a survey of the sexual behaviour of university students. Profile likelihoods can be computed, even when models are not identified and saturated profile likelihoods (making no assumptions about the non-response mechanism) are derived. Bayesian approaches are investigated and it is shown that their results may be highly sensitive to the prior specification. The proportion of responders answering 'yes' to the question 'have you ever had sexual intercourse?' was 73%. However, different assumptions about the non-responders gave proportions as low as 46% or as high as 83%. Our preferred estimate, derived from the response-saturated profile likelihood, is 67% with a 95% confidence interval of 58–74%. This is in line with other studies on response bias in the reports of young people's sexual behaviour that suggest that the respondents overrepresent the sexually active.     

函子的群逆

定义了函子的群逆,给出了函子的群逆存在的充要条件。     

The Two-interval Line-segment Problem

In this paper we define and study the non-parametric maximum likelihood estimator (NPMLE) in the one-dimensional line-segment problem, where we observe line-segments on the real line through an interval with a gap which is smaller than the two remaining intervals. We define the self-consistency equations for the NPMLE and provide a quick algorithm for solving them. We prove supremum norm weak convergence to a Gaussian process and efficiency of the NPMLE. The problem has a geological application in the study of the lifespan of species     

悬浮液进样平台石墨炉原子吸收光谱测定土壤中痕量镉

采用悬浮液进样平台石墨炉原子吸收光谱测定土壤中痕量镉,对测定条件、悬浮液稳定均匀性、基本改进剂、介质酸度及校正方法均进行了实验选择．本法的精密度为6.3%,检出出限为1.7*10-2g ,回收率为94%-107%