Macroeconomic forecasting using structural factor analysis

The use of a small number of underlying factors to summarize the information from a much larger set of information variables is one of the new frontiers in forecasting. In prior work, the estimated factors have not usually had a structural interpretation and the factors have not been chosen on a theoretical basis. In this paper we propose several variants of a general structural factor forecasting model, and use these to forecast certain key macroeconomic variables. We make the choice of factors more structurally meaningful by estimating factors from subsets of information variables, where these variables can be assigned to subsets on the basis of economic theory. We compare the forecasting performance of the structural factor forecasting model with that of a univariate AR model, a standard VAR model, and some non-structural factor forecasting models. The results suggest that our structural factor forecasting model performs significantly better in forecasting real activity variables, especially at short horizons.     

电动搬运车辆斩波器的应用分析

介绍以蓄电池和串励直流电动机为动力的电动搬动车辆用斩波器的种类，型号，参数，电路原理和应用情况。     

人民币实际有效汇率的变化对我国进出口的影响

本文从空间和时间两个角度全面考察了人民币实际有效汇率的变化对我国进出口的影响。结果表明,人民币汇率的变化会显著影响我国的进出口。但是,这种影响程度在1994年以后明显地出现了下降趋势。同时,人民币汇率变化对我国进出口的调整存在明显的J曲线效应,其中进口变动大致滞后于汇率变动2个季度,而出口则滞后1个季度,滞后期限均短于西方发达国家。本文分析了其中的原因并提出了相关建议。     

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.     

Persistence of Shocks to Output in Austria and Theories of Economic Growth

The paper analyzes the degree of output persistence in GDP in order toempirically discriminate between the Solow growth model, the perfect competition endogenous growth model and the imperfect competition endogenous growth model for the case of Austria. Wefind that a shock in the growth rate of output induces a permanent and larger effect on the level of GDP. This leads us to refute the Solow growth model and the perfect competition model of endogenous growth.We may not reject the imperfect competition growth model.     

Forecasting UK house prices: A time varying coefficient approach

Previous studies of UK house prices, developed from the demand and supply ofhousing or from the asset market approach have been poor in terms of robustness and ex-post forecasting ability. The UK housing market has suffered a number of structural changes, particularly since the early 1980s with substantial house price increases, financial market deregulation and the removal of mortgage market constraints through competition. Consequently, models which assume that the underlying data-generating process is stable and apply constant parameter techniques tend to suffer in terms of parameter instability. This article uses the Time Varying Coefficient (TVC) methodology where the underlying data-generating process in the UK housing market is treated as unstable. The estimation results of the TVC regression of UK house prices is compared with those obtained from three alternative constant parameter regressions. Comparisons of forecasting performance suggest the TVC regression out-performs forecasts from an Error Correction Mechanism (ECM), Vector Autoregressive (VAR) and an Autoregressive Time Series regression.     

关于所得税资产负债表债务法的思考

所得税“时间性差异”的概念和债务法的处理方法在国际上已有了进一步的认识和发展,在当今我国会计的国际化进程加快的情况下,引入“暂时性差异”的概念并采用资产负债表债务法来进行该差异的处理是所得税会计的发展趋势。本文通过对两种差异的深入研究及对资产负债表债务法与损益表债务法的比较分析,对资产负债表债务法在我国采用的现实基础及发展前景进行阐述。     

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.     

75kW中频感应加热电源的研制

针对中频感应加热电源对油田油井加热问题,本文采用PWM控制技术实现了功率可调。为使系统的功率因数较高,采用串联谐振和频率跟踪技术。中频感应加热电源采用IGBT作为开关器件,可工作在10 Hz-10 kHz频段。它充分利用中频趋肤效应、邻近效应和圆环效应原理,通过感应加热器和油管柱,使电能有效的转化为热能,从而达到原油降粘降稠、稳产高产的目的。