一排列问题的推广及其计数公式

对“全国大学生数学建模竞赛（１９９７）”的一道题进行推广：将ａｉｊ（１≤ｉ≤ｎ,１≤ｊ≤ｍ）排成一排或一个圆圈,当ａｉ１,ａｉ２,…,ａｉｍ（ｉ＝１,２,…,ｎ）相邻时,则将其看作一个整体而不考虑它们之间的顺序,则这种排列的个数Ｌｎ,ｍ与Ｒｎ,ｍ分别为：Ｌｎ,ｍ＝∑ｎｉ／０（－１）＾ｉ（ｍ！－１）＾ｉＣ＾ｉｎ（ｍｎ－（ｍ－１）ｉ）！,Ｒｎ,ｍ＝∑ｎｉ＝０（－１）＾ｉ（ｍ！－１）＾ｉＣ＾ｉｎ（ｍｎ－     

螺旋桨桨叶固有动力特性方法研究

应用有限元与边界元结构合的湿模态法对浸入静水域中螺旋桨桨叶进行固有动力特性研究,编制了３种单元组合模型与流固耦合计算分析程序;实桨计算结果与桨叶固有频率激振试验结果比较表明,计算值与实测值基本吻合,所采用的块体元、过渡元和厚壳元３种单元组合形成的有限元离散模型和Moriono双曲面元法在计算精度和计算效率方面比块体和厚壳有限元模型有所改善。     

微穿孔板-三聚氰胺吸音海绵-空腔复合结构声学性能优化设计

基于Johnson-Champoux-Allard（JCA）模型和微穿孔板理论,利用传递矩阵法建立了三聚氰胺吸音海绵不同填充方式形成的复合结构的吸声系数理论模型,并比较了其吸声性能：与单层微穿孔板结构a相比,微穿孔板-吸音海绵复合结构b和微穿孔板-吸音海绵-空腔复合结构c的吸声性能均有较大提升,微穿孔板-空腔-吸音海绵复合结构d的提升效果次之。分析了几何参数对复合结构b的吸声性能的影响,得出：微穿孔板的孔径越小,复合结构在中高频段的吸声效果越好;厚度越大,复合结构在高频段的吸声性能越低;穿孔率越大,复合结构在低频段的吸声性能越低;吸音海绵厚度的增加在总体上有利于提高复合结构的吸声效果。基于粒子群算法对复合结构b和c的吸声性能进行了优化,结果表明：与优化前的复合结构b相比,优化后的复合结构c的平均吸声系数从0.565 4提升至0.751 9;与优化后的复合结构b相比,其吸声性能几乎不变,但吸声材料厚度减少了30%,在保持良好吸声性能的同时实现了轻量化。     

PDP用压延铜箔表面黑化处理研究进展

压延铜箔表面黑化处理工艺复杂,生产成本高,在等离子显示领域中的应用受到极大限制。为了促进等离子显示屏（plasma display panel,PDP）用压延铜箔的发展,对其表面黑化处理工艺进行综述。通过阐述等离子显示屏的工作原理,总结归纳出PDP用压延铜箔的相关性能要求,着重介绍了PDP用压延铜箔的表面黑化处理工艺,为后续PDP用压延铜箔的研究提出结构致黑这一新的思路。最后通过分析PDP用压延铜箔表面黑化处理的生产现状,提出实际生产中存在的一些问题,以促进PDP用压延铜箔的发展。     

平行数据资料的一种非参数分析方法

将横剖面数据的秩统计量应用于平行数据资料,分析平行数据的整体变化趋势和每个变量的变化趋势及多个变量所具有的共同规律性等．最后结合我国各地城乡居民储蓄存款余额的数据进行实例分析。     

驻波管中介质板复透射系数的修正计算方法

为提高驻波管中复反射、复透射系数测试精度,基于驻波管中四传感器法,分析了透射管内透射反射波对测试精度的影响,推导出经修正的单层和多层介质板的复反射、复透射系数计算公式.通过对有机玻璃的测试,比较了透射管开口末端和吸声末端对测量结果的影响;通过对海绵与人造革复合结构的测试,比较了声波正、反向入射对复透射系数的影响.实验结果表明,修正公式能够提高驻波管中单层或多层介质板的复反射、复透射系数测试精度,降低对透射管末端吸声性能的要求.对多层均匀介质板,正、反两方向上的正入射复透射系数相同.     

Twisting the Dollar? On the Consistency of Short‐Run and Long‐Run Exchange Rate Expectations

We examine consistency properties of the exchange rate expectation formation process of short‐run and long‐run forecasts in the dollar/euro and yen/dollar market. Applying nonlinear consistency restrictions we show that in a simple expectation formation structure short‐run forecasts are indeed inconsistent with long‐run predictions. Moreover, we establish a ‘twist’ in the dollar/euro expectation formation process, i.e. market participants expect bandwagon effects in the short run, while they have stabilizing expectations in their long‐run forecasts. Applying a panel probit analysis we find that this twisting behavior is more likely to occur in periods of excess exchange rate volatility. Copyright © 2011 John Wiley & Sons, Ltd.     

Prediction in a Generalized Spatial Panel Data Model with Serial Correlation

This paper considers the generalized spatial panel data model with serial correlation proposed by Lee and Yu (Spatial panels: random components versus fixed effects. International Economic Review 2012; 53 : 1369–1412.), which encompasses many of the spatial panel data models considered in the literature, and derives the best linear unbiased predictor (BLUP) for that model. This in turn provides valuable BLUP for several spatial panel models as Special Cases. Copyright © 2016 John Wiley & Sons, Ltd.     

How helpful are spatial effects in forecasting the growth of Chinese provinces?

In this paper, we make multi‐step forecasts of the annual growth rates of the real gross regional product (GRP) for each of the 31 Chinese provinces simultaneously. Beside the usual panel data models, we use panel models that explicitly account for spatial dependence between the GRP growth rates. In addition, the possibility of spatial effects being different for different groups of provinces (Interior and Coast) is allowed for. We find that both pooling and accounting for spatial effects help substantially to improve the forecast performance compared to the benchmark models estimated for each of the provinces separately. It is also shown that the effect of accounting for spatial dependence is even more pronounced at longer forecasting horizons (the forecast accuracy gain as measured by the root mean squared forecast error is about 8% at the 1‐year horizon and exceeds 25% at the 13‐ and 14‐year horizons). Copyright © 2010 John Wiley & Sons, Ltd.     

Nowcasting and predicting data revisions using panel survey data

The qualitative responses that firms give to business survey questions regarding changes in their own output provide a real‐time signal of official output changes. The most commonly used method to produce an aggregate quantitative indicator from business survey responses—the net balance or diffusion index—has changed little in 40 years. This paper investigates whether an improved real‐time signal of official output data changes can be derived from a recently advanced method on the aggregation of survey data from panel responses. We find, in a New Zealand application, that exploiting the panel dimension to qualitative survey data gives a better in‐sample signal about official data than traditional methods. Out‐of‐sample, it is less clear that it matters how survey data are quantified, with simpler and more parsimonious methods hard to improve. It is clear, nevertheless, that survey data, exploited in some form, help to explain revisions to official data. Copyright © 2009 John Wiley & Sons, Ltd.