共查询到17条相似文献,搜索用时 15 毫秒
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文章在非线性成本函数的假定条件下,对Cournot寡头竞争模型进行改进,建立了基于对数成本函数的Cournot模型.并与经典Cournot模型的均衡结果进行对比分析.结论表明,改进后的模型与现实问题的吻合度更好. 相似文献
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真理具有两重性。其绝对性表现为在当时的历史条件下是绝对正确的东西 ;其相对性表现在随着时间的推移、科学技术的发展、原来正确的东西会被否定、淘汰 ,因而只具有相对性。例如 ,中国古代的四大发明 ,在发明的当时是绝对的高科技 ,对人类文明作出了无比巨大的贡献 ,这就是“四大发明”的绝对性 ;但在当代 ,几乎没有任何国家、地区、甚至绝大部分的部落还在坚持原始的四大发明 ,这就是四大发明的相对性。又例如 ,蒸气机的发明 ,推动并实现了产业革命 ,使资本主义由工场手工业时代跨越到大机器时代 ,其对人类经济发展的贡献是不言而喻的 ,这… 相似文献
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Victor Zarnowitz 《商业与经济统计学杂志》2013,31(4):293-311
The article presents extensive results from testing for bias and serially correlated errors in a collection of time series of quarterly multiperiod forecasts for six variables including real GNP growth, inflation, and unemployment. The analysis covers responses by 79 frequent participants in economic outlook surveys conducted regularly since 1968. It shows much greater incidence of apparently systematic errors for inflation than for the other variables. Also, the tests are more favorable to composite group forecasts than to most of the individual forecast sets. 相似文献
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We compare different approaches to accounting for parameter instability in the context of macroeconomic forecasting models that assume either small, frequent changes versus models whose parameters exhibit large, rare changes. An empirical out-of-sample forecasting exercise for U.S. gross domestic product (GDP) growth and inflation suggests that models that allow for parameter instability generate more accurate density forecasts than constant-parameter models although they fail to produce better point forecasts. Model combinations deliver similar gains in predictive performance although they fail to improve on the predictive accuracy of the single best model, which is a specification that allows for time-varying parameters and stochastic volatility. Supplementary materials for this article are available online. 相似文献