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231.
语言迁移现象既发生在母语与第一外语学习过程中,也同样发生在学习第二外语的过程中,并且因此而变得复杂有趣。多种语言本身的独特性和差异性,使多语际语言基础对第一、第二外语语音学习过程产生了相互影响和作用。本研究以西班牙大学生和中国西班牙语专业大学生为研究对象,通过对比研究中文普通话、英语和西班牙语在语音方面的特点,探索母语、第一外语、第二外语之间的相互关系,及其对语音学习所产生的作用和影响,为多语际语音习得与外语教学提供有价值的借鉴和经验。  相似文献   
232.
The evaluation of hazards from complex, large scale, technologically advanced systems often requires the construction of computer implemented mathematical models. These models are used to evaluate the safety of the systems and to evaluate the consequences of modifications to the systems. These evaluations, however, are normally surrounded by significant uncertainties related to the uncertainty inherent in natural phenomena such as the weather and those related to uncertainties in the parameters and models used in the evaluation.

Another use of these models is to evaluate strategies for improving information used in the modeling process itself. While sensitivity analysis is useful in defining variables in the model that are important, uncertainty analysis provides a tool for assessing the importance of uncertainty about these variables. A third complementary technique, is decision analysis. It provides a methodology for explicitly evaluating and ranking potential improvements to the model. Its use in the development of information gathering strategies for a nuclear waste repository are discussed in this paper.  相似文献   
233.
In risk assessment, the moment‐independent sensitivity analysis (SA) technique for reducing the model uncertainty has attracted a great deal of attention from analysts and practitioners. It aims at measuring the relative importance of an individual input, or a set of inputs, in determining the uncertainty of model output by looking at the entire distribution range of model output. In this article, along the lines of Plischke et al., we point out that the original moment‐independent SA index (also called delta index) can also be interpreted as the dependence measure between model output and input variables, and introduce another moment‐independent SA index (called extended delta index) based on copula. Then, nonparametric methods for estimating the delta and extended delta indices are proposed. Both methods need only a set of samples to compute all the indices; thus, they conquer the problem of the “curse of dimensionality.” At last, an analytical test example, a risk assessment model, and the levelE model are employed for comparing the delta and the extended delta indices and testing the two calculation methods. Results show that the delta and the extended delta indices produce the same importance ranking in these three test examples. It is also shown that these two proposed calculation methods dramatically reduce the computational burden.  相似文献   
234.
The present study uses the concept of technological efficacy derived from ecological psychology and design studies to offer an alternative way of analyzing how policy instruments affect change. Reasoning from this, the paper outlines a framework for analyzing policy instruments in terms of their affordances. We define affordances as the means through which an instrument exerts influence on its intended target audience. Using this approach, we contend that policy instruments may be analyzed as interfaces that organize social relations and create structures of opportunity and/or restrict possibilities for action. We argue that explicating the pathways through which instruments afford or constrain action is a central task for policy analysis. Our proposed framework of analysis builds on the idea that instruments yield effects by facilitating action and learning. We further contend that the actions that an instrument can facilitate or inhibit are determined by specific affordance modalities of the instrument in conjunction with contingencies of the actor and the policy environment. Examples from research policy are used to illustrate some of these effects.  相似文献   
235.
煤矿瓦斯爆炸事故单危险源风险度量模型研究   总被引:1,自引:0,他引:1  
本文研究了煤矿瓦斯爆炸事故危险源的分类,把危险源划分为人的不安全行为、机器设备不安全状态、环境不安全特征和管理缺陷四大类,并根据煤矿现场调查各类危险源的数据以及相应数学方法的特点,提出煤矿瓦斯爆炸事故人、机器设备(物)、环境、管理四类危险源的风险度量方法,在此基础上构建四类危险源的风险度量模型。研究表明,危险源的风险度量模型由风险发生的可能性、危险源重要度以及事故导致的损失构成;危险源风险发生的可能性,在具体应用中可以采用各类危险源的不可靠度、故障率等来衡量;危险源在事故中的重要度可以通过分析事故故障树种要素结构重要性获取。根据风险评价的结果,可以对危险源进行分级排序,从而为煤矿事故单危险源的控制提供依据。  相似文献   
236.
Economic issues linked to career counseling are a cause for concern to policy makers in developed countries because they expect career practitioners to provide evidence of the efficiency of career counseling interventions. The aim of this study was to test an individual evaluation method mixing time series (outcomes) and life narrative (processes). The method used 5 items related to 1 client's career decision self‐efficacy and studied the evolution of those items throughout the intervention of 1 career counselor (43 days). Changepoint analysis helped in identifying the changes that have to be taken into account for time series and which are contextualized in the client's verbatim analysis. This mixed method highlighted that the career counselor's intervention increased the client's career decision self‐efficacy. Practitioners could use the methodology proposed in this article to evaluate their interventions. They could also report their practice to clients, employers, and decision makers.  相似文献   
237.
This article presents a framework for economic consequence analysis of terrorism countermeasures. It specifies major categories of direct and indirect costs, benefits, spillover effects, and transfer payments that must be estimated in a comprehensive assessment. It develops a spreadsheet tool for data collection, storage, and refinement, as well as estimation of the various components of the necessary economic accounts. It also illustrates the usefulness of the framework in the first assessment of the tradeoffs between enhanced security and changes in commercial activity in an urban area, with explicit attention to the role of spillover effects. The article also contributes a practical user interface to the model for emergency managers.  相似文献   
238.
This paper studies an M/G/1 clearing queueing system with setup time and multiple vacations, in which all present customers in the system are served simultaneously and breakdowns may occur in busy or setup period. We investigate the stationary distribution of system size and the Laplace–Stieltjes transform of sojourn time. In addition, various performance measures are discussed, such as the mean system size at arbitrary time and the mean length of a vacation circle. Moreover, a cost analysis is carried out for this queueing system. Numerical results are presented to study the sensitivity of the system parameters on the expected cost function and system performances.  相似文献   
239.
Substantial evidence supports the value of outdoor education programs for promoting healthy adolescent development, yet measurement of program outcomes often lacks rigor. Accurately assessing the impacts of programs that seek to promote positive youth development is critical for determining whether youth are benefitting as intended, identifying best practices and areas for improvement, and informing decisions about which programs to invest in.We generated brief, customized instruments for measuring three outcomes among youth participants in Baltimore City Outward Bound programs: conflict management, emotional self-efficacy, and problem solving confidence. Measures were validated through exploratory and confirmatory factor analyses of pilot-testing data from two groups of program participants. We describe our process of identifying outcomes for measurement, developing and adapting measurement instruments, and validating these instruments.The finalized measures support evaluations of outdoor education programs serving urban adolescent youth. Such evaluations enhance accountability by determining if youth are benefiting from programs as intended, and strengthen the case for investment in programs with demonstrated success.  相似文献   
240.
Over the past generation, sexual minorities—particularly lesbian, gay, bisexual, and transgender (LGBT) persons—have gained increased visibility in the public arena. Yet organizational research has lagged behind in recognizing and studying this category of organizational members. This article offers a critical review of this growing body of research. More specifically, we identify and discuss four dominant scholarly frames that have informed LGBT organizational research from the late nineteenth century to date. The frames include a “medical abnormality,” “deviant social role,” “collective identity,” and “social distinctiveness” view of sexual minorities. We argue that these frames have profoundly shaped the scope and range of organizational scholarship devoted to sexual minorities by showing that scholars using such contrasted frames have been drawn to very different research questions with respect to sexual minorities. We document and discuss the main and contrasted questions asked within each of these frames and show how they have both enabled and constrained LGBT organizational research. We conclude by calling for more attention to the frames organizational scholars adopt when studying sexual minorities, but also for more research on both minority and majority sexual orientations in organizations.  相似文献   
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