Are microfinance markets monopolistic?

Do microfinance institutions (MFIs) operate in a monopoly, monopolistic competition environment or are their revenues derived under perfect competition markets? We employ the Panzar–Rosse revenue test on a global panel data to assess the competitive environment in which MFIs of five selected countries operate: Ecuador, India, Indonesia, Peru and Philippines, over the period 2005–2009. We estimate the static and the dynamic revenue tests, with analyses of the interest rate and the return on assets. We control for microfinance-specific variables such as capital-assets-ratio, loans-assets and the size of the MFI. The analyses also account for the endogeneity problem by employing the fixed-effects two-stage least squares and the fixed-effects system generalized method of moments. Our results suggest that MFIs in Peru and India operate in a monopolistic environment. We also find weak evidence that the microfinance industry in Ecuador, Indonesia and Philippines may operate under perfect competition.     

Distribution of parallel exchange rates in African countries

This paper investigates the distribution of parallel exchange rates in African countries using exploratory data analysis techniques and model fitting. Stable laws are fitted to empirical distributions using the maximum likelihood estimation method. Empirical evidence supports the stable hypothesis these distributions are positively skewed and have tails that are much heavier than Gaussian counterparts. The stable hypothesis is further supported by the “converging variance test,” which suggests that these distributions have infinite variance.     

An empirical comparison of continuous-time models of implied volatility indices

We explore the ability of alternative popular continuous-time diffusion and jump-diffusion processes to capture the dynamics of implied volatility indices over time. The performance of the various models is assessed under both econometric and financial metrics. To this end, data are employed from major European and American implied volatility indices and the rapidly growing CBOE volatility futures market. We find that the addition of jumps is necessary to capture the evolution of implied volatility indices under both metrics. Mean reversion is of second-order importance though. The results are consistent across the various metrics, markets, and construction methodologies.     

我国市场化改革对经济增长贡献的实证分析

市场化改革与经济增长是目前我国经济研究的一个热点问题。本文通过梳理我国经济增长方面相关的研究文献,指出了现有研究中在估计方法与数据方面的不足,提出了一个可行的改进方法。并根据扩展的新古典经济增长模型,利用我国30个省市区的面板数据,采取直接估计的方法,在全要素生产率中把技术进步与市场化改革加以分离,分别测度了技术进步与市场化改革对经济增长的贡献。我们发现我国的市场化改革对经济增长有着显著的正影响,贡献率达到14.22%。这对我国进一步推进市场化改革,促进经济增长,不断完善社会主义市场经济体制提供了理论上与实证上的支持。     

Estimating demand from eBay prices

This paper presents results for identification and estimation of the value distribution from eBay auction prices. The paper presents results for eBay type auctions with independent private values and unobserved participation. It is first shown that the distribution of values is identified from observing the distribution of prices and knowing the distribution of potential bidders. The main identification result presents conditions for which the distribution of values and the distribution of potential bidders are simultaneously identified. Not surprisingly, the intuition is similar to the standard results for identifying demand from observed equilibrium prices. The estimation method suggested by the identification results is used to estimate the value distribution for the “C5” Chevrolet Corvette sold on eBay. The results suggest that a simple OLS model on prices will over estimate the mean value of the item. The estimation results are then used to calculate the optimal reserve price for these cars. The estimated optimal reserves are compared to the actual reserves. Actual hidden reserves are set much higher than actual non-hidden reserves. The evidence suggests sellers set Buy-It-Nows and hidden reserves optimally to account for re-listing opportunities.     

推定征税的权义结构分析

推定征税具有保障国家财政收入、税收公平的合理性,也有被滥用,从而侵害纳税人权益的危险。分析推定课税的权义结构,可厘清税务机关和纳税人双方在其中的职权与职责、权利与义务,并通过纳税人协助义务、税务机关推定征税权和纳税人异议权的相互制约和激励,以达成推定征税的正当与合理适用。     

浅谈水利水电工程概预算的编制与应用

本文详细介绍了水利水电工程概预算编制依据、步骤、注意事项,探讨了水利水电工程概预算编制过程中常见问题的分析处理。     

一种基于小波域的盲水印算法

提出了一种基于小波变换后频域系数的特征以及水印图像数据的奇偶性盲水印算法。该算法先将图像进行两级小波变换，根据LL2中数据特点和水印数据的奇偶性在HL2、LH2、HH2嵌入水印。在检测水印的时候，只需要拥有少量数据，就可以完成水印的提取。攻击实验研究表明：此算法具有很好的抗规则剪切、不规则剪切、加噪、压缩的能力，具有很好的鲁棒性。     

A note on the Robust Trend and ARARMA methodologies used in the M3 Competition

This brief note describes two of the forecasting methods used in the M3 Competition, Robust Trend and ARARMA. The origins of these methods are very different. Robust Trend was introduced to model the special features of some telecommunications time series. It was subsequently found to be competitive with Holt’s linear model for the more varied set of time series used in the M1 Competition. The ARARMA methodology was proposed by Parzen as a general time series modelling procedure, and can be thought of as an alternative to the ARIMA methodology of Box and Jenkins. This method was used in the M1 Competition and achieved the lowest mean absolute percentage error for longer forecasting horizons. These methods will be described in more detail and some comments on their use in the M3 Competition conclude this note.     

软件项目进度估算的模糊方法

软件项目进度的估算是软件项目管理的重要组成部分,当开发新型项目时,由于没有历史经验,精确的甚至基于概率的估算方法都比较困难,而且可信度也较低,文章采用了模糊-概率的方法来进行进度的估算,在模糊运算中采用基于卷积的模糊算子,该算子具有扩散性较低的特点。