应用Microsoft Excel软件计算渐开线圆柱齿轮尺寸的研究

为了快速、准确地计算渐开线圆柱齿轮的几何尺寸和测量尺寸公法线长度或者圆棒跨距,在没有齿轮设计软件的情况下,文章对应用Excel表来计算的方法进行了研究,其计算速度比用一般函数计算器提高数百倍,大大提高了齿轮设计人员和工艺人员的工作效率。     

会计稳健性、经济租金与企业剩余收益

通过实证研究会计稳健性与企业剩余收益的关系,以及会计稳健性与经济租金对企业剩余收益的交互影响,发现会计稳健性与企业的剩余收益显著正相关,而会计稳健性和经济租金对企业剩余收益的交互影响较为复杂,其中：稳健性与研发密度、广告密度对剩余收益有显著的正面影响,但稳健性与企业规模、市场份额、流通股比例和资本密度对剩余收益的交互效应不明显。可见,提高会计稳健性,并不一定能为企业带来额外的经济租金收益。     

Casinos,casino size,and crime: A panel data analysis of Michigan counties

Growth in legal gaming in the United States over the past quarter century or so is well-documented. One important factor fueling this growth was the passage of the Indian Gaming Regulatory Act of 1988, which permitted Native American tribes to establish, under agreements or “compacts” with the states in which they are located, casinos offering what is known as Class III gaming: slot machines, blackjack, roulette, and other games. Since the passage of the Act, there have been 21 Native American casinos established in Michigan. Also, three non-Native American casinos opened in Detroit in 1999 and 2000. This growth in the number of casinos has sparked a wide-ranging debate over the social and economic impacts of casino development.The purpose of this research is to focus on the crime issue in the broader casino debate. We investigate the impact of these Michigan casinos on the rates of burglary, robbery, larceny and motor vehicle theft (property crimes) in casino host counties as well as in nearby counties. We employ a panel data set with annual observations on all 83 Michigan counties for the period 1994–2010. The dataset includes crime rates taken from the FBI crime data series, variables for the presence of a casino in a county or in a nearby county, the scale of a casino's operations as measured by revenues, and a variety of control variables suggested by the broader literature investigating the factors that determine crime rates generally.Our results suggest that in most cases the property crime rates studied are not affected by the presence or size of a casino in a county or in a nearby county. The largest such impact, which is negative, is for motor vehicle theft. The size of a casino does have a small positive effect on the motor vehicle theft rate.     

Saving–investment correlations, capital mobility and crowding out: some further results

This study attempts to reassess the evidence on the degree of capital mobility and crowding out by applying a varying coefficients model to data on 19 OECD countries over the 1971–1999 period. Our period-specific results strongly support the crowding-out effect as well as the low capital mobility argument for this group of countries as a whole. However, the strength of the crowding-out effect appears to weaken and the degree of capital mobility to increase in the 1990s as compared to the 1970s and 1980s. We also classify countries into five groups according to the relative size of the government sector. Our group-specific results indicate that the degree of capital mobility is generally lower and the crowding-out effect generally stronger, in country groups with smaller governments. The differences are especially evident when we compare the group with largest government size with all other groups, those differences between the latter being much more modest. However, significant differences in the country-specific results suggest that it is prudent to be cautious when we draw conclusions about crowding-out and capital mobility for specific countries from the period-wise or group-wise results. This is particularly important in drawing policy implications for specific countries.     

Firm Size Distribution and Growth*

Abstract Empirical documentation of the sectoral distribution of firm size for a set of European countries reveals substantial differences. We study the relationship between productivity growth at the industry level and size structure. A positive and robust relation is found between average firm size and growth. We ask why size should matter for growth by considering the role of innovation to construct a test based on the differential effect of size on growth according to various indicators of R&D intensity. Our results indicate that larger size fosters productivity growth because it allows firms to take advantage of all the increasing returns associated with R&D. We argue that our test can be interpreted as a test of reverse causality, which lends support to the view that firm size has a causal impact on growth.     

Robustness issues in multilevel regression analysis

A multilevel problem concerns a population with a hierarchical structure. A sample from such a population can be described as a multistage sample. First, a sample of higher level units is drawn (e.g. schools or organizations), and next a sample of the sub‐units from the available units (e.g. pupils in schools or employees in organizations). In such samples, the individual observations are in general not completely independent. Multilevel analysis software accounts for this dependence and in recent years these programs have been widely accepted. Two problems that occur in the practice of multilevel modeling will be discussed. The first problem is the choice of the sample sizes at the different levels. What are sufficient sample sizes for accurate estimation? The second problem is the normality assumption of the level‐2 error distribution. When one wants to conduct tests of significance, the errors need to be normally distributed. What happens when this is not the case? In this paper, simulation studies are used to answer both questions. With respect to the first question, the results show that a small sample size at level two (meaning a sample of 50 or less) leads to biased estimates of the second‐level standard errors. The answer to the second question is that only the standard errors for the random effects at the second level are highly inaccurate if the distributional assumptions concerning the level‐2 errors are not fulfilled. Robust standard errors turn out to be more reliable than the asymptotic standard errors based on maximum likelihood.     

Simpler Probabilistic Population Forecasts: Making Scenarios Work

The traditional high-low-medium scenario approach to quantifying uncertainty in population forecasts has been criticized as lacking probabilistic meaning and consistency. This paper shows, under certain assumptions, how appropriately calibrated scenarios can be used to approximate the uncertainty intervals on future population size and age structure obtained with fully stochastic forecasts. As many forecasting organizations already produce scenarios and because dealing with them is familiar territory, the methods presented here offer an attractive intermediate position between probabilistically inconsistent scenario analysis and fully stochastic forecasts.     

基于人口规模和城市化水平测算的城乡建设用地需求预测研究——以辽东凤城市为例

以辽宁东部凤城市为研究区域,采用1997年至2005年凤城市的人口、经济等统计数据,从作为土地需求预测基础的社会化发展水平预测入手,利用不同的预测模型对凤城市的人口规模、城镇化水平进行预测,并通过对比各预测模型的测算数据,提出科学方案并做最优选择,最终得出适宜凤城市发展的测算数据,以此为依据预测城乡建设用地需求量,为凤城市城乡建设用地合理发展及新一轮的土地利用总体规划修编提供数据支撑和理论依据。     

我国上市公司投资质量测度指标体系的设计与应用

上市公司投资质量的测度指标包括投资规模(选用回归方程的残差指标)与投资结构(选用多元化指数DT指标)两部分指标。使用2007年至2009年我国上市公司数据进行实证检验,发现该指标体系具有科学性。运用加权平均法对2009年我国上市公司投资质量进行综合的计分与排名,进一步验证了该指标体系具有可行性。     

Which school systems sort weaker students into smaller classes? International evidence

We examine whether the sorting of high- and low-achieving students into classes of different sizes results in a regressive or compensatory pattern of class sizes for 18 national school systems. Sorting effects are identified by subtracting the causal effect of class size on performance from their total correlation. Our empirical results reveal strongly compensatory patterns of sorting within and especially between schools in many countries. Only the United States, which has a decentralized education finance and considerable residential mobility, exhibits regressive between-school sorting. Between-school sorting is more compensatory in systems with ability tracking. Within-school sorting is more compensatory where administrators rather than teachers assign students to classrooms.