由情感因素看教师角色的转换

情感因素在现代教育特别是现代外语教育中的地位越来越突出.积极情感可显著提升教学质量,积极情感的养成需要教师对其角色进行调整.具体来讲,教师要通过尊重学生的个性化选择、以诚相待和培养学生自信心等方法,实现自身由"讲师"向"导师"的角色转换.     

Lessons from the Grey Area: A Closer Inspection of At-risk Gamblers

The study takes a closer look at at-risk gamblers, with the objective to see how they differ from no-risk gamblers. The data comes from a national gambling survey in 2002, and the age group is 15–74 years. The sample consists of 4188 current gamblers with no current gambling problems or pathology. The analysis includes cross-tabulations and a logistic regression. The results show that at-risk gamblers differed substantially from no-risk gamblers in terms of demographic characteristics, gambling behaviour and the presence of other assumed risk factors. Demographic segments with a higher risk of falling into the at-risk group are men, young people, divorced or single people, and non-western immigrants. Furthermore, gambling problems in the family, beginners luck and misconceptions about winning chances significantly increased the odds for at-risk gambling. The study concludes that at-risk gamblers deserve more attention from research, that their similarity with problem gamblers increases the likelihood that many of them will eventually develop a gambling problem, and that their tendency to be superstitious about winning chances might be exploited in preventive work.     

Bayesian t-tests for correlations and partial correlations

In this paper, we develop Bayes factor based testing procedures for the presence of a correlation or a partial correlation. The proposed Bayesian tests are obtained by restricting the class of the alternative hypotheses to maximize the probability of rejecting the null hypothesis when the Bayes factor is larger than a specified threshold. It turns out that they depend simply on the frequentist t-statistics with the associated critical values and can thus be easily calculated by using a spreadsheet in Excel and in fact by just adding one more step after one has performed the frequentist correlation tests. In addition, they are able to yield an identical decision with the frequentist paradigm, provided that the evidence threshold of the Bayesian tests is determined by the significance level of the frequentist paradigm. We illustrate the performance of the proposed procedures through simulated and real-data examples.     

Notes and Communications “A DECISION THEORY EXAMPLE IN FOOTBALL”: A COMMENT*

Janssen and Daniel analyzed the choice between a one- or a two-point conversion for a particular game situation in college football. Their decision criteria was maximum expected utility based on a von Neumann-Morgenstern utility function defined over the games outcomes. An alternative approach based on a stochastic dominance criterion is presented that does not rely on knowledge of the relative importance of tying vs. winning; rather, it relies on a notion of consistency in the sequential problem.     

STOCHASTIC COST-VOLUME-PROFIT ANALYSIS IN A COMPETITIVE OLIGOPOLY

Previous stochastic cost-volume-profit (CVP) models have assumed that the firm was operating under either perfect competition or monopolistic conditions. This paper presents a stochastic CVP model applicable to oligopolistic competition. Each firm is assumed to maximize a linear function of the expected value and the standard deviation of its random profits. The result is a game-theoretic model that is solved using the concept of a Nash equilibrium. The results of the model are used to examine a firm's competitive strength. The model can be easily modified to accommodate a measure of risk based on the capital asset pricing theory.     

A DECISION THEORY EXAMPLE IN FOOTBALL

In the 1967 Harvard-Cornell football game, Harvard was ahead 14–0 late in the game when Cornell scored two touchdowns. On both occasions, Cornell tried and failed on the two-point conversion attempt and lost the game 14–12. Postgame arguments were divided on the merits of Cornell's strategy. For this frequently occurring scenario in college football, we derive a maximum expected utility decision rule for the decision of kicking versus running/passing based on the relative utility of a win, a tie, or a loss and the probabilities of success with a kick as opposed to a run/pass.     

STOCHASTIC COST-VOLUME-PROFIT ANALYSIS WITH A LINEAR DEMAND FUNCTION

In this paper we incorporate a linear demand function to model the price-volume causal relationship into stochastic cost-volume-profit (CVP) analysis. We assume that the objective function is to maximize expected profit; other objective functions are also discussed and compared. A linear stochastic model follows from which probabilistic statements can be easily obtained if the random variables are assumed to be multivariate normal. The basic framework is shown to be a special case of project value maximization where project value is the cash flow of the project discounted for time and risk according to the capital asset pricing model. Moreover, an intertemporal extension that considers inventory is developed. In summary, a new approach to stochastic CVP analysis that incorporates the management decision process in an uncertain environment is developed.     

英语专业基础阶段听力课教学中的困难因素与对策

本文根据第二语言习得理论并结合教学实践 ,着重探讨英语专业基础阶段听力课教学中的困难因素和提高听力课教学质量的主要基本技能。     

影响英语听力理解的若干因素及教学措施

本文分析了影响英语听力理解的若干因素 ,重点从知识、情感、文化和预测能力等方面进行了探讨 ,并在此基础上提出“促进知识的迁移 ,提高识别语言的能力”等若干教学措施 ,将教学设计的方法用于听力教学过程。     

Asymptotic Bias in Parameter Estimation of AR-Processes Using Recursive Least Squares with Exponential Forgetting

The recursive least squares technique is often extended with exponential forgetting as a tool for parameter estimation in time-varying systems. The distribution of the resulting parameter estimates is, however, unknown when the forgetting factor is less than one. In this paper an approximative expression for bias of the recursively obtained parameter estimates in a time-invariant AR( n_a ) process with arbitrary noise is given, showing that the bias is non-zero and giving bounds on the approximation errors. Simulations confirm the approximation expressions.