关键事件技术及其应用——以制造商转换行为的研究为例

作为一种定性研究方法,关键事件技术特别适用于理论发展和管理有效性等研究目的。目前,该方法被广泛应用于教育、管理、零售、服务接触以及关系管理等领域进行探索性研究,其信度和效度也一再得到检验和证明。本文首先介绍了关键事件技术,并将其运用到制造商转换行为的研究之中。研究表明:价格、产品质量、物流能力、公司采购战略、服务质量是影响制造商转换的最为重要的原因。而且,不同的转换原因对制造商的满意度有不同的影响。在进一步分析的基础上,本文还得出85%的制造商转换属于复杂转换以及关系对顾客保留的影响可能与供应商所能提供的顾客价值有关等等富有意义的结论。     

从学生误译看翻译中逻辑思维转换的意义

由于所处的地理环境和文化传统不同,英语民族和汉语民族在逻辑思维方式上存在不少差异。在英汉翻译过程中,从理解原文到组织译文,英汉两种思维模式很可能会互相干扰。根深蒂固的母语思维可能影响译者对原文的理解,同时英语思维定式也会对译文的组织产生干扰。即是说,逻辑思维转换与运用的正确与否是导致误译的主要原因之一,能否在英汉两种思维模式之间顺利转换是翻译成功的重要因素。     

Statistical analysis of error for fourth-order ordinary differential equation solvers

We develop an autoregressive integrated moving average (ARIMA) model to study the statistical behavior of the numerical error generated from three fourth-order ordinary differential equation solvers: Milne's method, Adams–Bashforth method and a new method that randomly switches between the Milne and Adams–Bashforth methods. With the actual error data based on three differential equations, we desire to identify an ARIMA model for each data series. Results show that some of the data series can be described by ARIMA models but others cannot. Based on the mathematical form of the numerical error, other statistical models should be investigated in the future. Finally, we assess the multivariate normality of the sample mean error generated by the switching method.     

Markov regime switching in mean and in fractional integration parameter

We propose a specific general Markov-regime switching estimation both in the long memory parameter d and the mean of a time series. We employ Viterbi algorithm that combines the Viterbi procedures in two state Markov-switching parameter estimation. It is well-known that existence of mean break and long memory in time series can be easily confused with each other in most cases. Thus, we aim at observing the deviation and interaction of mean and d estimates for different cases. A Monte Carlo experiment reveals that the finite sample performance of the proposed algorithm for a simple mixture model of Markov-switching mean and d changes with respect to the fractional integrating parameters and the mean values for the two regimes.     

Role of stylized features in constructing better estimators

This article discusses the role played by stylized features of financial time series in constructing better estimators for the model parameters. We study in detail one such estimator for the transition probabilities of a simple regime switching model. The estimator is based on the squared autocovariances of the time series, which has been discussed in several empirical studies of economic and financial time series. The effectiveness of this estimator in improving the estimation accuracy is investigated, using both finite sample and asymptotic computations. We also report simulation results to confirm our findings and to extend our conclusions over a bigger region of the parameter space.     

Identification-robust moment-based tests for Markov switching in autoregressive models

ABSTRACT

This paper develops tests of the null hypothesis of linearity in the context of autoregressive models with Markov-switching means and variances. These tests are robust to the identification failures that plague conventional likelihood-based inference methods. The approach exploits the moments of normal mixtures implied by the regime-switching process and uses Monte Carlo test techniques to deal with the presence of an autoregressive component in the model specification. The proposed tests have very respectable power in comparison with the optimal tests for Markov-switching parameters of Carrasco et al. (2014 Carrasco, M., Hu, L., Ploberger, W. (2014). Optimal test for Markov switching parameters. Econometrica 82(2):765–784.[Crossref], [Web of Science ®] , [Google Scholar]), and they are also quite attractive owing to their computational simplicity. The new tests are illustrated with an empirical application to an autoregressive model of USA output growth.     

普通高校体育选项课之分层教学与目标教学的有机整合

根据普通高校体育选项课教学大纲的要求,对分层教学组织形式和目标教学法进行了系统研究,认为二者的有机整合可以有效提高普通高校体育教学的效果。分层教学与目标教学有机整合是分层制订分别适合不同高校大学生的教学目标和考核目标,因材施教,因需指导,因层评价和动态组合等,是帮助学生提高体育学习效果的较好方法,能够让学生最大限度地发挥自身潜力,从而促进大学生身心健康的发展,并帮助他们养成终身体育意识和体育习惯。     

语码的选择与转换

语码选择与转换是一种普遍的社会语言现象。本文对语码砖换的特点、作用和类型进行了简单的介绍和分析。通常影响语码转换的主要因素有:语言团体、语境、话题、参与交际者的身份、个性等。文章通过对中国大学生在普通话与方言的转换方面所进行的调查分析,推导出语言团体和社会准则是制约语码转换的重要因素。     

Testing Business Cycle Asymmetries Based on Autoregressions With a Markov-Switching Intercept

Implications of two concepts of asymmetry—deepness and steepness—are investigated for autoregressive processes with a Markov-switching intercept. The formulas for the skewness of these processes and the skewness of the first differences of these processes are derived. The parameter restrictions leading to nondeepness and nonsteepness are presented for the special case of a first-order autoregression and two states. It is shown that these restrictions imply that previous tests for asymmetries in autoregressive processes with a Markov-switching intercept can lead to wrong conclusions. In an empirical application of the developed tests, the U.S. unemployment rate is found to be steep.     

BOOST－PFC电路反馈环节的优化设计

介绍了平均电流控制ＢＯＯＳＴ─ＰＦＣ电路的原理，建立了电流环和电压环的小信号简化模型，讨论了双环反馈环节的设计原则和方法，提出最优设计的思想和数学模型，并以一种ＢＯＯＳＴ─ＰＦＣ电路为例进行优化设计，计算模拟结果显示优化后有关指标好于优化前。