Seasonal decomposition and forecasting of telecommunication data: A comparative case study

In this paper, forecasting models for the monthly outgoing telephone calls in a University Campus are presented. The data have been separated in the categories of international and national calls as well as calls to mobile phones. The total number of calls has also been analyzed. Three different methods, namely the Seasonal Decomposition, Exponential Smoothing Method and SARIMA Method, have been used. Forecasts with 95% confidence intervals were calculated for each method and compared with the actual data. The outcome of this work can be used to predict future demands for the telecommunications network of the University.     

The effect of income taxation on the labor supply of married men in Sweden

This paper presents labor supply functions estimated on a sample of prime age Swedish males. The model used takes account of the nonlinear character of individuals' budget sets caused by the progressive income tax. It also allows preferences to vary between individuals. Calculations with the estimated functions, using a partial equilibrium framework, indicate a sizeable effect of the income tax on hours of work. The average expected deadweight loss of the income tax is found to be approximately 20 percent of tax revenue.     

The effect of annual changes in automobile fuel economy standards

Since 1978 the Federal government has regulated the fuel economy of new cars sold in the United States. The purpose of Corporate Average Fuel Economy (CAFE) standards is to lessen the national dependence on foreign oil. Through the use of theoretical and empirical models this paper examines the impact of CAFE standards on the automobile industry and on energy consumption. It is shown that CAFE standards may or may not save energy. If CAFE does save energy, it does so at a prohibitive cost to the economy. CAFE standards are also shown to have a number of perverse impacts on the automobile industry as well as consumers.     

Geometrical Interpretation of the Mean and the Constant in a Box-Jenkins Time Series Model

Certain manuals and computer programs mistakenly identify the mean with the constant in Box-Jenkins time series models. In this paper, it will be shown that (a) the mean and the constant have different values in autoregressive models, and (b) they have an algebraic and graphical relationship.     

Estimation of location of discontinuity in a density

Here we propose a few estimators of θ, in addition to those studied in Goria (1978), the point of discontinuity of the probability density $$f(x,\theta ) = \frac{1}{{2\Gamma (\alpha )}}e^{ - |x - \theta |} |x - \theta |^{\alpha - 1} ,$$ for $$0< \alpha< 1, - \infty< x< \infty , - \infty< \theta< \infty .$$ We establish the consistency and the optimality of the Bayes and the maximum probability estimators. Despite their nice properties, these estimators are not easy to compute in this case and their effective computation depends on the knowledge of the exponent α. Hence, we propose another class of estimators, dependent upon the spacings of the observations, computable without actual knowledge of the value of α as long as it is known that α < α₀ < 1: we show that these estimators converge at the best possible rate. We further demonstrate, using a modified version of the maximum probability estimator's technique, that the tails of the density do not substantially effect their efficiency. Finally a bivariate family of densities, having a ridge dependent on the parameter θ, is considered and it is shown that this family exhibits features similar to the univariate case, and thus, the necessary modifications of the arguments of the univariate case are utilized for the estimation of θ in this bivariate example.     

Computerization and Structural Change

I develop three measures of structural change on the basis of U.S. data: changes in occupational composition, changes in input–output technical coefficients, and changes in capital coefficients. Using pooled cross-section, time-series data for 44 industries over the period from 1970 to 1990, I find that computer investment per worker has had a positive and significant effect on the degree of occupational change and changes in input and capital coefficients.     

Symposium on Social Capital: Introduction

This symposium contains three papers that discuss aspects of social capital. Social capital has become a major focus of research in many social sciences. Its increased prominence in economics reflects a general increase in interest in questions that have traditionally been deemed sociological. Regardless of one's opinion of social capital per se , this broadening of questions addressed within economics has been very salutary.     

Analysis and Forecast of the State of Environmental Protection in Russia

The main purpose of the present study is to analyse the emission dynamics of atmospheric and water pollutants in Russia and cost of their removal in the 1980s and early 1990s, and to forecast them by means of a Dynamic Input–Output Model according to different scenarios of future economic development till 1998. Main results of the work are:– methodological principles have been elaborated for singling out the environmental protection sector within the national economy;– a method has been offered for including the ecological block into a Dynamic Input–Output Model of the Russian economy;– a method of data preparation has been elaborated for the ecological block of the above-named model, the data base which characterizes the ecological situation in Russia has been formed and analysed;– calculations for 1994–1998 have been executed for forecasting the economic and ecological development of Russia using the above-mentioned model and the results obtained have been analysed. The results showed that if the existing tendencies towards low environmental protection capital costs remain the same, then the negative environmental impact will increase. In order to implement ecological programs and international agreements, to increase the proportion of removed pollutants, it is necessary to increase substantially expenditures on purifying water and air resources. The proportion of environmental protection investments in the total amount of the national economy capital costs should increase by up to 12–40% according to different scenarios of the economic development and different purposes of the environmental protection policy.     

New Evidence from Brazil on Trade Liberalization and Productivity Growth*

This article presents evidence on the positive effect of international trade on productivity growth using industrial level data preceding and following Brazil's trade liberalization in 1988–90. Our data reveal large and widespread productivity improvement across industries after barriers to trade were drastically reduced. Econometric results confirm the association between trade liberalization and productivity growth and show that the impact was indeed substantial: The observed tariff reduction in the period brought a 6% estimated increase in total factor productivity growth rate and a similar impact on labor productivity.