Information Technology As A Factor Of Production: The Role Of Differences Among Firms

Despite evidence that information technology (IT) has recently become a productive investment for a large cross-section of firms, a number of questions remain. Some of these issues can be addressed by extending the basic production function approach that was applied in earlier work. Specifically, in this short paper we: 1) control for individual firm differences in productivity by employing a ‘firm effects’ specification, 2) consider the more flexible translog specification instead of only the Cobb-Douglas specification, and 3) allow all parameters to vary between various subsectors of the economy.

We find that while ‘firm effects’ may account for as much as half of the productivity benefits imputed to IT in earlier studies, the elasticity of IT remains positive and statistically significant. We also find that the estimates of IT elasticity and marginal product are little-changed when the less restrictive translog production function is employed. Finally, we find only limited evidence of differences in IT's marginal product between manufacturing and services and between the ‘measurable’ and ‘unmeasurable’ sectors of the economy. Surprisingly, we find that the marginal product of IT is at least as high in firms that did not grow during 1988–1992 sample period as it is in firms that grew.     

The Benefit Function Approach to Modeling Price-Dependent Demand Systems: An Application of Duality Theory

In this article, we advocate more extensive use of the benefit function in specifying price-dependent or inverse demand models. We demonstrate how duality theory may be used to establish the interrelationships between the Marshallian (or Hicksian) inverse demands and Luenberger's adjusted price functions, allowing estimable inverse demands to be derived directly from a benefit function. We estimate two systems of inverse demands for Japanese quarterly fish consumption. Results indicate that the procedures and methods employed here appear promising, and may prove beneficial for quantity and welfare analysis when modeling systems of inverse demand functions.     

Neoclassical versus Frontier Production Models? Testing for the Skewness of Regression Residuals*

The empirical literature on production and cost functions is divided into two strands. The neoclassical approach concentrates on model parameters, while the frontier approach decomposes the disturbance term to a symmetric noise term and a positively skewed inefficiency term. We propose a theoretical justification for the skewness of the inefficiency term, arguing that this skewness is the key testable hypothesis of the frontier approach. We propose to test the regression residuals for skewness in order to distinguish the two competing approaches. Our test builds directly upon the asymmetry of regression residuals and does not require any prior distributional assumptions.     

Hyperbolic Discounting and Consumer Patience: The Case of Korea

ABSTRACT

In this article, we test whether the consumption pattern in Korea exhibits a time-inconsistent discounting behavior compared to the conventional exponential discounting. We derive the quasi-hyperbolic Euler equation and estimate it using the generalized method of moments (GMM). The estimation results show that Korean consumers exhibit a time-inconsistent quasi-hyperbolic discounting behavior in general, but the pattern of inconsistency in consumption behavior, in particular the degree of impatience, depends on the estimation period, in particular whether it includes financial crisis periods in 1997–98 and 2008–11.     

A discrete and a continuous-time model based on a technical trading rule

In this article we propose a model in discrete and continuoustime that incorporates explicitly a technical trading rule inthe specification of the volatility. The proposed discrete-timemodel is an alternative to GARCH-type processes. We derive conditionsfor the covariance and strict stationarity of the discrete-timeprocess and we study the estimation and inference problems.We also analyze the conditions under which the discrete-timeprocess converges in distribution to a diffusion process. Toillustrate the proposed model and compare it with the GARCHspecification, we analyze the daily closing stock prices oftwo major U.S. companies (Microsoft and Oracle), two stock indices(DAX and NASDAQ) and two U.S. Dollar exchange rates (Euro andSterling)     

一种基于区域搜索的全局运动估计与补偿算法

开展全局运动估计与补偿研究是进行动态目标检测中的基础和前提。在总结现有运动估计与补偿方法的基础上,提出一种基于图像分割区域的运动性和大小的全局运动估计与补偿算法。首先,通过建立区域搜索的全局运动模型,同时进行区域定性分割和区域大小排序;然后,根据误差最小化准则在指定的分割区域中进行线性递归搜索,利用门限准则寻找出最佳的运动估计参数;最后,根据双线性内插法获得运动位移量。实验结果比较可知,所提算法较三步搜索算法(TSS)和全局搜索算法(FSA)等传统算法具有更高的准确性(图像平移帧差)和实时性(算法运行时间),能够很好地实现运动背景的全局校正。     

Labour adjustment costs: Estimation of a dynamic discrete choice model using panel data for Greek manufacturing firms

In this paper we estimate a dynamic structural model of employment at firm level. Our dataset consists of a balanced panel of 2790 Greek manufacturing firms. The empirical evidence of this dataset stresses three important stylized facts: (a) there are periods in which firms decide not to change their labour input, (b) there are periods of large employment changes (lumpy nature of labour adjustment) and (c) the commonality is employment spikes to be followed by smooth and low employment growth periods. Following Cooper and Haltiwanger [Cooper, R.W. and Haltiwanger, J. “On the Nature of Capital Adjustment Costs”, Review of Economic Studies, 2006; 73(3); 611–633], we consider a dynamic discrete choice model of a general specification of adjustment costs including convex, non-convex and “disruption of production” components. We use a method of simulated moments procedure to estimate the structural parameters. Our results indicate considerable fixed costs in the Greek employment adjustment.     

Competition in banking: A disequilibrium approach

The Rosse–Panzar revenue test for competitive conditions in banking is based on observation of the impact on bank revenue of variation in factor input prices. We identify the implications for the H-statistic of misspecification bias in the revenue equation, arising when adjustment towards market equilibrium is partial and not instantaneous. In simulations, fixed effects estimation produces a measured H-statistic that is severely biased towards zero. Empirical results for the banking sectors of the Group of Seven (G7) countries corroborate our principal finding, that a dynamic formulation of the revenue equation is required for accurate identification of the H-statistic.     

几种发射分集OFDM系统信道估计方法性能评估

给出了3种基于发射分集的OFDM系统信道估计方法,分别从训练序列对算法的影响、估计准确度、算法复杂度和算法适用性等方面对各自性能作了分析比较,并进行了仿真.分析比较和仿真结果表明,训练序列对3种算法的影响很大,通过训练序列的正交化设计,LS和EM算法可以得到很大程度的简化;EM算法与LS算法估计精度相当,信噪比较大时,多项式模型算法估计精度要远远高于LS和EM算法;总体上来说,多项式模型算法复杂度最高,EM算法复杂度最低.     

基于多元线性回归的装饰工程快速估价模型

针对目前装饰工程陕速估价方法的不足，以及装饰工程造价组成的特点，建立一种基于多元线性回归的快速估价新模型。以住宅类建筑为例，建立其多元线性回归模型，结合SPSS软件对样本分析，结果表明，其线性回归模型显著，同时，内墙、外墙、楼地面和窗的回归系数也非常显著。通过计算回归值与实际值的误差，发现误差比较理想，该模型具有很好的实用价值。