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161.
通过首次对近5年SCI、EI、ISTP收录我校论文数和增长率进行统计、分析,初步了解其发展状况和趋势,找出存在问题及问题的因素,从而提出一些浮浅认识以供商榷。  相似文献   
162.
Drawing on British data from two annual sweeps of the ISSP eight years apart in 1994 and 2002, for modules focusing on 'Family and Changing Gender Roles', this paper examines the extent to which changes in women's labour market participation, changing ideologies/discourses of gender and changing forms of intimate relationships are affecting the ways in which couples organize household money, and the implications of such changes for recent theories of intimate relationships. The analysis indicates that by 2002, the type of relationship respondents had established, together with their social class position, were both independently related to the ways in which they managed money, after controlling for socio-economic and cultural or discursive factors. Our findings also provide a degree of support for the thesis of a partial decline in the male breadwinner model of gender, as indicated by small declines in the use of the relatively inegalitarian female whole wage and housekeeping allowance systems which were most likely to be used by married couples and cohabiting fathers, expressing relatively traditional ideologies/discourses of breadwinning - and a slight increase in the use of the partial pool, which was most likely to be used by childless cohabiting couples in which male partners expressed less traditional ideologies of breadwinning and women were in middle-class jobs with incomes high enough to facilitate partially separate finances. We also suggest, however, that in so far as cohabiting couples earning different amounts define equality as contributing equally to household expenditure, it is possible that rather than being associated with shifts to greater equality in access to money for personal spending and saving, the partial pool may be associated with marked inequalities, because it may enable gender inequalities generated in the labour market to be more directly transposed into inequalities within households, despite the decline of traditional discourses of male breadwinning and the increasing importance of egalitarian ideologies of co-provisioning.  相似文献   
163.
164.
The results of Hoeffding (1956), Pledger and Proschan (1971), Gleser (1975) and Boland and Proschan (1983) are used to obtain Buehler (1957) 1-α lower confidence limits for the reliability of k of n systems of independent components when the subsystem data have equal sample sizes and the observed failures satisfy certain conditions. To the best of our knowledge, for k ≠ 1 or n, this is the first time the exact optimal lower confidence limits for system reliability have been given. The observed failure vectors are a generalization of key test results for k of n systems, k ≠ n (Soms (1984) and Winterbottom (1974)). Two examples applying the above theory are also given.  相似文献   
165.
In this paper we consider the problem of estimating the reliability of an exponential component based on a Ranked Set Sample (RSS) of size n. Given the first r observations of that sample, 1≤r≤n, we construct an unbiased estimator for this reliability and we show that these n unbiased estimators are the only ones in a certain class of estimators. The variances of some of these estimators are compared. By viewing the observations of the RSS of size n as the lifetimes of n independent k-out-of-n systems, 1≤k≤n, we are able to utilize known properties of these systems in conjunction with the powerful tools of majorization and Schur functions to derive our results.  相似文献   
166.
The distributions of coherent systems with components with exchangeable lifetimes can be represented as mixtures of distributions of order statistics (k-out-of-n systems) from possibly dependent samples by using the concept of the signature of Samaniego (1985 Samaniego , F. ( 1985 ). On closure of the IFR class under formation of coherent systems . IEEE Trans. Reliabil. R-34 : 6972 .[Crossref], [Web of Science ®] [Google Scholar]). This representation, together with Rychlik's (1993 Rychlik , T. ( 1993 ). Bounds for expectation of L-estimates for dependent samples . Statistics 24 : 17 .[Taylor & Francis Online] [Google Scholar]) results, can be used to obtain sharp bounds on the distribution (or the reliability) function and on the expected lifetime of the system. Also, this representation can be used to determine the asymptotic behavior of the hazard rate of the system when the order statistics are ordered in the hazard rate order. Moreover, the lifetime distributions of coherent systems (and in particular, of order statistics) can also be represented as generalized mixtures (that is, mixtures with some negative weights) of distributions of series system lifetimes by using the concept of the minimal signature defined by Navarro et al. (2007a Navarro , J. , Ruiz , J. M. , Sandoval , C. J. ( 2007a ). Properties of coherent systems with dependent components . Commun. Statist. Theory Methods 36 : 175191 .[Taylor & Francis Online], [Web of Science ®] [Google Scholar]). This representation can also be used to determine the final behavior of the hazard rate of the system through the behavior of the hazard rate of the series systems. In particular, it can be used to show that the order statistics are, under some conditions, asymptotically hazard rate ordered. However, in general, this result is not true, that is, the order statistics need not be hazard rate ordered.  相似文献   
167.
The evolution of computers is currently in a period of rapid change, stimulated by radically cheaper and smaller devices for processing and memory. These changes are certain to provide major opportunities and challenges for the use of computers in statistics. This article looks at history and current trends, in both general computing and statistical computing, with the goal of identifying key features and requirements for the near future. A discussion of the S language developed at Bell Laboratories illustrates some program design principles that can make future work on statistical programs more effective and more valuable.  相似文献   
168.
《随机性模型》2013,29(4):415-437
Abstract

In this paper, we study the total workload process and waiting times in a queueing system with multiple types of customers and a first-come-first-served service discipline. An M/G/1 type Markov chain, which is closely related to the total workload in the queueing system, is constructed. A method is developed for computing the steady state distribution of that Markov chain. Using that steady state distribution, the distributions of total workload, batch waiting times, and waiting times of individual types of customers are obtained. Compared to the GI/M/1 and QBD approaches for waiting times and sojourn times in discrete time queues, the dimension of the matrix blocks involved in the M/G/1 approach can be significantly smaller.  相似文献   
169.
ABSTRACT

In this article, we develop a new method, called regenerative randomization, for the transient analysis of continuous time Markov models with absorbing states. The method has the same good properties as standard randomization: numerical stability, well-controlled computation error, and ability to specify the computation error in advance. The method has a benign behavior for large t and is significantly less costly than standard randomization for large enough models and large enough t. For a class of models, class C, including typical failure/repair reliability models with exponential failure and repair time distributions and repair in every state with failed components, stronger theoretical results are available assessing the efficiency of the method in terms of “visible” model characteristics. A large example belonging to that class is used to illustrate the performance of the method and to show that it can indeed be much faster than standard randomization.  相似文献   
170.
ABSTRACT

The growing commercialisation of migration, often through a multiplicity of labour market intermediaries, is an issue of increasing academic interest. We seek to contribute to an emerging research agenda on the migration industries by exploring how one of the key actors that constitutes it, recruitment agencies, sits at the nexus between flexible labour market structures and migrant labour. Interviews with U.K. labour providers and low-wage employers form the evidence base for an analysis of the strategies developed by recruiters to derive commercial gain from connecting the so-called ‘supply’ and ‘demand’ sides of the flexible international labour market. We seek to contribute to understandings of the analytical categories within migration systems by illustrating how the migration industry interacts with other key stakeholders to structure international migration.  相似文献   
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