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排序方式: 共有962条查询结果,搜索用时 15 毫秒
51.
3G“杀手级”业务的产生和培育   总被引:1,自引:1,他引:0  
3G时代的到来无疑为电信市场的发展带来了机遇和挑战,到底怎样的电信业务能在新时代中脱颖而出,成为业内人士心驰神往的“杀手级”业务,的确是个耐人寻味的问题。在对“杀手级”业务所应具备的基本条件作探讨的同时,对“杀手级”业务的培育策略进行了分析,认为“杀手级”业务本不存在,它的形成是市场多方因素共同努力的结果。  相似文献   
52.
A dynamic model of a heterogeneous population is studied. Particles belonging to a population are divided, at every time t, into a finite number of classes according to their types and the partition changes over time. The role of the occupancy numbers, namely the cardinality of each class, is highlighted. The relationship between the stochastic process of occupancy numbers and the process of particle types is analyzed. The main goal of this paper is the estimation of the lifetime of each particle at a given time t, when the observed data are the history of the process of the number of dead particles up to t. Furthermore, a discrete time approximation of the filter is given.  相似文献   
53.
The relative performance of a component of a series system in two different environments is considered. The conditional probability of the failure of the system due to the failure of the specified component given that the system failed before time t is regarded as a measure of relative importance of the component to the system. A U-statistic test for checking the equality of the relative importance of the component to the system in two different environments against the alternative that the relative importance is smaller in one of the environments, is proposed. Some simulation results for estimating the power of the test are reported. The proposed test is applied to one real data set and it is seen that a different aspect of the data is brought out by this comparison than that by the comparisons of the absolute importance functions such as the subsurvival functions, considered in earlier studies.  相似文献   
54.
引入域上典型群的生成问题所得的成果;对局部环R上典型群生成问题研究,构造度量函数及一平延,为局部环R上典型群向域F上的典型群导入,给出典型群的非双曲型.  相似文献   
55.
文章介绍了第四代移动通信的概念,主要应用的技术以及4G的发展前景.  相似文献   
56.
介绍一个能对空气处理过程进行自动分析的计算机软件,该软件能生成湿空气的焓-湿图,显示空气处理过程,并对娄在动处理,为空调系统设备选择提供其础数据。  相似文献   
57.
We study the Kolmogorov–Smirnov test, Berk–Jones test, score test and their integrated versions in the context of testing the goodness-of-fit of a heavy tailed distribution function. A comparison of these tests is conducted via Bahadur efficiency and simulations.  相似文献   
58.
Summary.  We consider the stochastic mechanisms behind the data that were collected by the solar X-ray sensor (XRS) on board the GOES-8 satellite. We discover and justify a non-trivial mean–variance relationship within the XRS data. Transforming such data so that their variance is stable and its distribution is taken closer to the Gaussian distribution is the aim of many techniques (e.g. Anscombe and Box–Cox). Recently, new techniques based on the Haar–Fisz transform have been introduced that use a multiscale method to transform and stabilize data with a known mean–variance relationship. In many practical cases, such as the XRS data, the variance of the data can be assumed to increase with the mean, but other characteristics of the distribution are unknown. We introduce a method, the data-driven Haar–Fisz transform, which uses the Haar–Fisz transform but also estimates the mean–variance relationship. For known noise distributions, the data-driven Haar–Fisz transform is shown to be competitive with the fixed Haar–Fisz methods. We show how our data-driven Haar–Fisz transform method denoises the XRS series where other existing methods fail.  相似文献   
59.
作为对经济理论和理论核心的综合和深化,G函数引导出了一些新的探索。其中主要有初始模型的选取,试验焦点的确定,以及实验领域的搜索等。出于对经济理论核心的精确化需要,超越对数函数成为初始结构模型的可选择形式,由此导致数据试验的焦点内容集中。若其他条件不变,作为边界条件,固定数量向量会成为实验的基本出发点,在其中所进行的搜索会日益成为实际验证所关注的内容。  相似文献   
60.
We develop statistical inferential tools for estimating and comparing conditional tail expectation (CTE) functions, which are of considerable interest in actuarial science. In particular, we construct estimators for the CTE functions, develop the necessary asymptotic theory for the estimators, and then use the theory for constructing confidence intervals and bands for the functions. Both parametric and non-parametric approaches are explored. Simulation studies illustrate the performance of estimators in various situations. Results are obtained under minimal assumptions, and the general Vervaat process plays a crucial role in achieving these goals.  相似文献   
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