课堂环境中加大口语语言输入的效果研究

如何有效地提高学生口语能力是大学英语教学中重要课题。本实验以非英语专业学生为研究对象,在有限的课堂教学时间内通过加大口语语言素材的输入,提高学生的口语交际能力,以寻求一种有效的教学模式。     

Pricing-to-market tests in instrumental regressions: Case of the transportation equipment industry

Pricing-to-market (PTM) theory suggests that exporting monopolistic firms adjust their destination-specific mark-ups in the face of exchange rate shocks. A large proportion of the existing evidence for PTM comes from Wald tests applied to OLS- and IV-estimated parameters of single-equation models. Such tests can seriously over-reject in the presence of endogeneity and weak instruments so that some of the available results supporting PTM could be spurious. In this paper we revisit the PTM evidence for Japanese and German exporting firms in the transportation equipment industry. Using the model of Marston (1990), we apply exogeneity and LR-LIML-based tests for which the error probability is controlled irrespective of the quality of the available instruments. Our results show right-hand-side endogeneity in almost all of the examined PTM equations. In addition, we find that statistical decisions often differ depending on whether they are based on the traditional Wald test or on our proposed test.The authors would like to thank Philippe Barla, Jean-Thomas Bernard, Christos Constantatos, Larry Schembri, seminar participants at the Bank of Canada, and two anonymous referees for useful comments and suggestions. Thanks also to Richard Marston for providing data. Finally, a special thanks to Marjorie Santos for excellent research assistance. All remaining errors are our own and should not be attributed to the Bank of Canada.First version received: May 2002/Final version received: December 2002     

Volatility Relationship between Crude Oil and Petroleum Products

This paper utilizes calculated historical volatility and GARCH models to compare the historical price volatility behavior of crude oil, motor gasoline and heating oil in U.S. markets since 1990. We incorporate a shift variable in the GARCH/TARCH models to capture the response of price volatility to a change in OPEC’s pricing behavior. This study has three major conclusions. First, there was an increase in volatility as a result of a structural shift to higher crude oil prices after April 1999. Second, volatility shocks from current news are not important since GARCH effects dominate ARCH effects in the variance equation. Third, persistence of volatility in all commodity markets is quite transitory, with half-lives normally being a few weeks.

The Negligence Rule in the Presence of Judicial Corruption and Social Norms

This paper investigates the phenomenon of judicial corruption and incorporates it into Polinsky, A. M. (1980). Strict liability vs. negligence in a market setting. American Economic Review, 70, 363–367 framework so as to analyze the efficiency of the negligence rule. By shedding light on the role of social norms in regard to the phenomenon of judicial corruption, this analysis provides implications for policy. First, more prevalent corruption at the status quo tends to intensify the extent of the corruption itself and, as a result, the effectiveness of the government’s corruption enforcement is greatly lessened. This implies that an excessively lenient policy of corruption may result in an uncontrollable consequence; once corruption becomes rampant, it is costly to bring it down. Of great importance, in the presence of such a corruption effect, the social optimum cannot be achieved based on the negligence rule and the equivalence between the strict liability and negligence rule fails. Secondly, the attitude of the society toward a corrupt judge plays a crucial role in governing the effectiveness of an efficient wage arrangement. If the society can fully accept a corrupt judge, corruption will never be controlled even with the incentive wage scheme.

基于特征增量的新类识别方法研究

在分类应用的过程中,经常会出现新的类别,导致数据分布发生显著变化,使得原分类模型不再适用。如何识别新的类别使分类模型能适应其出现已经成为一个亟需解决的问题。本文提出基于特征增量的SVDD(支持向量数据描述)新类识别方法。该方法在SVDD算法的基础上,通过增加新特征,扩大特征空间维度从而提高模型对于新类的识别能力。在多个数据集上的实验结果表明,该方法能有效识别新类,使更新后的模型具有更高的准确度。     

如何提高高职学生专业基础课的学习兴趣

多数高职院校学生不愿学习、不会学习。改变这种状况,首先要从高职院校教师入手,提高教师思想品质和教学艺术,其次要采取各种方法激发学生的学习兴趣,比如多给学生一些鼓励,细化教学环节,总结应用必要的教学技巧。     

城市“夹心层”的住房问题及解决途径——以广州市为例

住房是人类生活稳定的第一要素,是人类最基本的需求之一,也是每个个体化生活方式的终极归宿形式之一,因此住房是关系国计民生的重大经济和社会问题。在政府推出各种住房保障政策后,产生了仍然存在住房困难但被政策忽略的群体——"夹心层"。本文将主要分析"夹心层"由来,探讨其收入范围,并提出解决途径,以改善居住环境、维持社会稳定、营造和谐氛围。     

论我国中间阶层及其社会效应

一个稳定的中间阶层对于一个国家的经济结构和金融结构有着极大的正面作用。本文从3个方面对我国的中间阶层进行研究,首先分析了中间阶层的分层依据,并概要地介绍了中间阶层在我国的发展,进而着重指出中间阶层在社会发展中具有保持社会稳定,实现共同富裕等多种社会效应。     

优化社会阶层结构促进社会和谐稳定

社会主义和谐社会建设作为我们全面建设小康、加快推进现代化事业的一项战略任务和重要内容,已经被提上了重要议事日程。而社会的和谐稳定、民众的共同富裕,都离不开社会阶层结构的优化、中等收入者阶层的不断扩大。为此,需要我们以科学发展观总揽改革发展全局,从多方面入手,努力塑造“橄榄型”的阶层结构模式。     

污水处理厂的脱氮除磷改造

结合城镇污水处理厂脱氮除磷改造工程实例,对老氧化沟进行功能区划分、设备改造：增加好氧区溶解氧浓度,降低缺（厌）区溶解氧浓度;同时适当增容,延长氧化沟水力停留时间和污泥泥龄。运行结果表明,系统出水主要指标稳定达到GB18918—2002一级A标准。