A Biproportional Filter to Compare Technical and Allocation Coefficient Variations

In input-output analysis there are two alternate possibilities between Leontief's mechanism (fixed technical coefficients) and Ghosh's mechanism (fixed allocation coefficients). Testing the long-term consistency of these mechanisms entails comparing input-output matrices over time. This paper challenges the value of proportional filters (separate comparisons of column and row coefficients) and introduces the biproportional filter that allows simultaneous comparison of column and rows. An application is proposed using French input-output tables for 1980 and 1993. The stability of column coefficients cannot be taken for granted and, generally, for any sector, both row and column coefficients are found to change simultaneously.     

LEAST SQUARES ESTIMATES OF THE REGIONAL EMPLOYMENT MULTIPLIER: AN APPRAISAL*

Basically, we have attempted to show the following in the course of setting out the algebra of regression analysis of selected regional employment multiplier models: (1) When the basic features of the model are shaped by the assumption of an unlagged response of local employment to changes in export employment, the least squares estimates of the multipliers are highly sensitive to the export coefficients vector A, given the sample observation matrix X. In a completely disaggregated model such as Equation (21), the multipliers are solely determined by the export coefficients and thus are entirely independent of sample observations. However, this independence does not hold in the case of a partially disaggregated model. The identity relation is also destroyed when a lag relationship is introduced into a completely disaggregated model. (2) A simple lag model produces results bascially different from those obtained by an unlagged model if the overall differences between current and lagged observations are significant. (3) Given a matrix of sample observations on employment, it is possible to estimate the upper limits of a least-squares aggregate multiplier and its variance simply from knowledge of the export coefficients (4) The export coefficients vector has also an important bearing upon the correlation coefficient. The correlation is unity if and only if the export coefficients vector is proportional to the local employment coefficients vector, while it is zero if and only if the export coefficients vector is a vector all of whose elements are one. Also, the correlation coefficient is equal to one when a completely disaggregated model is used. There is finally the question of what these results mean in terms of the formulation of a multiplier model. First of all, in view of the crucial importance of the export coefficients and the difficulties of estimating them, most of the existing models do not seem to offer promising results. Furthermore, all the models examined here have made some simplifying assumption with respect to the constancy of the export coefficients. It remains highly uncertain whether these coefficients are reasonably stable over time. Of course, it would be theoretically more acceptable to relax the assumption of the invariance of export coefficients and to obtain such coefficients at different points of time for each industry. However, this would be accomplished only at the cost of increased difficulties of estimating larger numbers of export coefficients. In addition, there is some doubt as to the validity of the assumption that export employment is proportional to export sales. Since a lag relationship is important not only in terms of attempts to formulate multiplier models more realistically, but also in terms of its significant effect on the multiplier values obtained, the nature and the form of a lagged response and its estimation problems need to be investigated in depth. Finally, problems of least squares bias and efficiency, inference, and prediction which may arise in the context of various models presented here remain to be investigated. A detailed analysis of such problems must be the subject of further investigation.     

NOTE ON THE INCLUSION OF SITE CLASSIFICATION INFORMATION IN EQUATIONS TO ESTIMATE STRONG GROUND MOTIONS

Two main regression methods have been proposed for using site category information within ground motion prediction equations, these are: (a) joint estimation of the site category coefficients and the magnitude and distance coefficients; or (b) estimation of site category coefficients by using the residuals from the equation derived without considering soil conditions. Method (a) requires each record be assigned a site category whereas for method (b), because it relies on residuals, site information can be missing for some records. This short note finds that if the mean of the transformed distances within each site category is the same then the two methods give the same site coefficients. If, however, these means are significantly different then method (b) can yield incorrect site coefficients.     

Site Classification System and Site Coefficients for Shallow Bedrock Sites in Korea

Recent studies have shown that the site coefficients obtained from site response analyses of Korean soil sites are significantly different from those specified in the current Korean seismic code, especially in the short-period portion of site response. This difference is mainly attributed to the shallow bedrock conditions (bedrock depth usually less than 30 m) in Korea. This study proposes a new site classification system and site coefficients for shallow bedrock sites based on site response analyses of more than 300 sites. The proposed site classification scheme and site coefficients proposed in this study are an improvement over the current seismic code and previous studies.     

Contributions to Change in the Input-Output Model: The Search for Inverse Important Coefficients

The relationship between changes in input-output structural coefficients and changes in the coefficients of the Leontief inverse is explained in a calculus-based framework. Knowledge of this relationship is essential for understanding how structural changes in one sector are transmitted across the economy, and is useful in forming updates to I-O tables given limited information. Empirically, we identify those coefficients likely to be the most important in causing inverse changes. We find that a selective and systematic updating procedure can lead to accurate updates without the need for complete data.     

An Economic Analysis of Biproportional Properties in an Input-Output System

Various methods, such as biproportional adjustment and econometric estimating have been used to generate time series for input-output tables. In this paper, temporal changes of input-output coefficients are examined in order to analyze their behavior. Within the Chicago Region Econometric Input-Output Model, a set of input- output relationships has been extracted analytically for the period 1980–1997. Using the empirical evidence for Chicago, this paper conducts econometric time series analysis to determine whether or not certain coefficients or sets of coefficients exhibit tendencies toward stability or predictable change or whether others require more extensive econometric estimation.     

A LONG RUN ECONOMIC EFFECT ANALYSIS OF ALTERNATIVE TRANSPORTATION FACILITY PLANS—REGIONAL AND NATIONAL

Initially we explained the main part of our model which enabled us to estimate and compare the long run and global economic effects of alternative transportation facility plans. Usually the short run effects of this kind of regional economic impact have been analyzed by input-output models, and the long run effects by econometric models. However, in this model, the input-output model and the econometric model were combined so as to enable us to analyze the global and long run economic effects. The interregional trade pattern coefficients and input coefficients change endogenously in each year in this model. It has previously been assumed that the fixedness of interregional trade pattern coefficients and input coefficients are the weakest points in applying the interregional input-output model for long run studies. In our model, on the contrary, variation of these coefficients has central importance. We then showed the results which were obtained from applying this model to a comparison of the long run economic effects of alternative bridge construction plans over the Japan Inland Sea. The results obtained from this demonstrative calculation are reasonable. Thus, we think, this model has sufficient applicability to the comparison of economic effects of alternative plans for nationwide transportation facility improvement. However, the variations of production cost differentials between regions are given exogenously in this model. To make them endogenous, agglomeration economies should be considered more precisely. In that case, the applicability and the precision of this model could be improved.     

Bayesian Spatial Filtering for Hedonic Models: An Application for the Real Estate Market

This article presents a Bayesian method based on spatial filtering to estimate hedonic models for dwelling prices with geographically varying coefficients. A Bayesian Adaptive Sampling algorithm for variable selection is used, which makes it possible to select the most appropriate filters for each hedonic coefficient. This approach explores the model space more systematically and takes into account the uncertainty associated with model estimation and selection processes. The methodology is illustrated with an application for the real estate market in the Spanish city of Zaragoza and with simulated data. In addition, an exhaustive comparison study with a set of alternatives strategies used in the literature is carried out. Our results show that the proposed Bayesian procedures are competitive in terms of prediction; more accurate results are obtained in the estimation of the regression coefficients of the model, and the multicollinearity problems associated with the estimation of the regression coefficients are solved.     

THE ROLE OF ERROR STRUCTURE IN SIMULATIONS ON REGIONAL INPUT-OUTPUT ANALYSIS*

Previous simulation experiments on regional input-output analysis have concluded that regional purchase coefficients are more important than technical coefficients in contributing to multiplier accuracy. This paper shows that the multiplicative error structure used in those experiments may have biased the results. A new error structure, combining a multiplicative and an additive component is introduced, and simulations are conducted on randomly generated models. The analysis shows that the results are sensitive to the relative magnitudes of the two error components, as well as to the closure of the model.     

宁波保国寺大殿风振性能研究

为了更科学地保护我国传统木构建筑,需要研究我国江南地区传统木构建筑的风振性能,为此,以江南地区最古老、保存最完整的佛教木构建筑——保国寺大殿的主殿为例进行风振性能研究。首先基于三维激光扫描获得的真实可靠的保国寺大殿的几何信息,采用SAP2000有限元软件建立主殿的有限元模型,并进行动力特性分析。再利用MATLAB软件编写脉动风速时程,并将风压作用于有限元模型上分析,得到主殿的风振响应。得到结构模态、位移时程曲线、位移谱曲线、加速度响应,并对时程位移风振系数和规范风振系数进行对比。结构的振动响应主要由前三阶振型控制,在强风荷载作用下,最容易出现的变形就是南北向振动、东西向振动和扭转振动;各个典型节点的最大位移均在侧向位移容许值内;迎风面阑额中心位移最大、屋面上半部次之、屋面下半部及檐柱柱头最小;主殿相连的两个部分的加速度相差较多,屋面和屋身的连接节点应成为日后保国寺大殿的保护重点;时程风振系数变化与规范风振系数的变化规律不同是因为结构横向刚度分布不均匀;时程风振系数是规范风振系数的1.2~1.4倍,这是由于按照规范计算风振系数的过程中只考虑了第一阶振型的影响而忽略其他所有振型的结果;规范风振系数的计算只适用于形状、质量沿高度不变的高耸结构,不适用于类似本研究中的低矮木构传统房屋结构。     

Molecular transport of methane, ethane and nitrogen and the influence of diffusion on the chemical and isotopic composition of natural gas accumulations

Laboratory experiments have been performed to determine diffusion coefficients of natural gas components (methane, ethane and nitrogen) and isotope fractionation effects under simulated in situ pressure (up to 45 MPa effective stress) and temperature conditions (50–200°C) in water‐saturated pelitic and coarse‐grained rocks. Effective diffusion coefficients of molecular nitrogen (0.39 × 10^?11 to 21.6 × 10^?11 m² sec^?1 at 90°C) are higher than those for methane (0.18 × 10^?11 to 18.2 × 10^?11 m² sec^?1 at 90°C). Diffusive flux rates expressed in mass units are generally higher for N₂ than for CH₄. Both methane and (to a lesser extent) nitrogen diffusion coefficients decrease with increasing total organic carbon (TOC) content of the rock samples because of sorption processes on the organic matter. This effect decreases with increasing temperature. Effective diffusion coefficients increase upon a temperature increase from 50 to 200°C by a factor of four. Effective diffusion coefficients and steady‐state diffusive flux decrease with effective stress. Stationary diffusive fluxes drop by 50–70% for methane and 45–62% for nitrogen while effective diffusion coefficients are reduced by 38% (CH₄) and 32–48% (N₂), respectively. Isotope fractionation coefficients of diffusive transport are higher for methane (?1.56 and ?2.77‰) than for ethane (?0.84 and ?1.62‰). Application of the experimental results to geological systems show that diffusive transport has only a low transport efficiency. Significant depletion of natural gas reservoirs by molecular diffusion is only expected in cases of very poor caprock qualities (in terms of thickness and/or porosity) and over extended periods of geological time. Under these circumstances, the chemical and isotopic composition of a gas reservoir will change and maturity estimates based on these parameters may be deceptive. To account for these potential effects, nomograms have been developed to estimate diffusive losses and apply maturity corrections.     

ON THE PLAUSIBILITY OF THE SUPPLY-DRIVEN INPUT-OUTPUT MODEL: EMPIRICAL EVIDENCE ON JOINT STABILITY*

ABSTRACT. This paper addresses the issue of the plausibility of the supply-driven input-output model from an empirical standpoint. We suggest that requiring production coefficients to remain perfectly fixed during an application of the supply-driven input-output model is unnecessarily restrictive given the extensive use of approximation methods in mathematics, economics and regional science. Simulations with the supply-driven version of an input-output table for a representative region are shown to result in changes in the corresponding production coefficients well within conventional tolerance levels.     

INTERREGIONAL MIGRATION ANALYSIS

A formula for migration rate, proposed by Bogue, Shryock and Hoermann (1957), is modified to yield a simple coefficient of migration intensity for the analysis of the intensity of interregional streams of migration among the 72 oblasts, krays and autonomous republics of the RSFSR, the principal republic of the Soviet Union. The coefficient, which eliminates the impact of the populations of both region of origin and region of destination on the value of the coefficient, is obtained by dividing the shares of all regions of origin in the migration to each region of destination by the shares of the regions of destination in the total population of all regions. The 5112 coefficients of migration intensity are arrayed in a table and subjected to some preliminary analysis of migration patterns. The basic pattern is determined by 171 coefficients with values of 5 or higher, accounting for 3.4 percent of the total number of coefficients.     

Comparison of total electron content calculated using the IRI with observations in China

Values of total electron content (TEC) calculated using the International Reference Ionosphere (IRI-86 and IRI-90) are compared with the observations at Xinxiang based on the Faraday rotation measurement. It is found that the IRI gives acceptable values with respect to the observations during low solar activity. Generally the IRI-90 is better than the IRI-86 and the URSI coefficients are better than the CCIR coefficients in the calculation of TEC. Making use of the foF2 and M(3000)F₂ calculated using the Asia Oceania Region F₂-layer mapping (AOR) instead of using the CCIR or the URSI coefficients, the IRI gives more accurate TEC values. In October-April during high solar activity, however, the IRI obviously underestimates TEC in the daytime, which could be due to an improper topside electron density profile.     

Variation in North American dart points and arrow points when one or both are present

The appearance of the bow and arrow in North America as a weapon-delivery system is predicted to have prompted an increase in variation among antecedent projectile points that tipped darts propelled by atlatls. Attributes of dart points are expected to display greater variation with the appearance of the bow as prehistoric artisans experimentally sought points that worked effectively as arrow points. Attributes of arrow points are predicted to also initially display much variation. Subsequent to the initial burst of variation, less-effective variants of attributes were winnowed out, causing a reduction in variation of attributes of both dart points and arrow points. Both coefficients of variation for individual attributes and summed coefficients of variation for multiple attributes of three sequences of projectile points from evolutionarily independent areas in North America confirm these predictions.     

Generation of Multiple Earthquake Accelerograms Compatible with Spectrum Via the Wavelet Packet Transform and Stochastic Neural Networks

The principal purpose of this article is to present a novel methodology based on wavelet packet transform techniques and stochastic neural networks to generate more artificial earthquake accelerograms from available data, which are compatible with specified response spectra or the design spectra. The proposed method uses the decomposing capabilities of wavelet packet transform on earthquake accelerograms, and the learning abilities of stochastic neural network to expand the knowledge of the inverse mapping from response spectrum to coefficients of wavelet packet transform of earthquake accelerogram. This methodology results in a stochastic ensemble of wavelet packet transform coefficients of earthquake accelerograms and, they are used to the generate accelerograms applying the inverse wavelet packet transform. Finally, an interpretive example is presented which uses an ensemble of recorded accelerograms to train and test the neural network, aiming at the demonstration of the method effectiveness.     

Balancing Spatial and Non-Spatial Variation in Varying Coefficient Modeling: A Remedy for Spurious Correlation

This study discusses the importance of balancing spatial and non-spatial variation in spatial regression modeling. Unlike spatially varying coefficients (SVC) modeling, which is popular in spatial statistics, non-spatially varying coefficients (NVC) modeling has largely been unexplored in spatial fields. Nevertheless, as we will explain, consideration of non-spatial variation is needed not only to improve model accuracy but also to reduce spurious correlation among varying coefficients, which is a major problem in SVC modeling. We consider a Moran eigenvector approach modeling spatially and non-spatially varying coefficients (S&NVC). A Monte Carlo simulation experiment comparing our S&NVC model with existing SVC models suggests both modeling accuracy and computational efficiency for our approach. Beyond that, somewhat surprisingly, our approach identifies true and spurious correlations among coefficients nearly perfectly, even when usual SVC models suffer from severe spurious correlations. It implies that S&NVC model should be used even when the analysis purpose is modeling SVCs. Finally, our S&NVC model is employed to analyze a residential land price data set. Its results suggest existence of both spatial and non-spatial variation in regression coefficients in practice. The S&NVC model is now implemented in the R package spmoran.     

A Comparison of Spatially Varying Regression Coefficient Estimates Using Geographically Weighted and Spatial‐Filter‐Based Techniques

Geographically weighted regression (GWR) is a technique that explores spatial nonstationarity in data‐generating processes by allowing regression coefficients to vary spatially. It is a widely applied technique across domains because it is intuitive and conforms to the well‐understood framework of regression. An alternative method to GWR that has been suggested is spatial filtering, which it has been argued provides a superior alternative to GWR by producing spatially varying regression coefficients that are not correlated with each other and which display less spatial autocorrelation. It is, therefore, worthwhile to examine these claims by comparing the output from both methods. We do this by using simulated data that represent two sets of spatially varying processes and examining how well both techniques replicate the known local parameter values. The article finds no support that spatial filtering produces local parameter estimates with superior properties. The results indicate that the original spatial filtering specification is prone to overfitting and is generally inferior to GWR, while an alternative specification that minimizes the mean square error (MSE) of coefficient estimates produces results that are similar to GWR. However, since we generally do not know the true coefficients, the MSE minimizing specification is impractical for applied research.     

Modulation of the solar daily geomagnetic variation

A least squares spectral analysis is used to investigate cyclic and seasonal changes of the harmonic coefficients of the solar daily and semi-diurnal variation over the 24 year interval from 1 January 1960 to 31 December 1983 at a single magnetic observatory (Dourbes, Belgium). As a preparation for the treatment of other long runs of observations a statistical method is presented to combine the output of the spectral and harmonic analyses of a group of stations. The annual means of the Fourier coefficients are significantly correlated with the solar cycle. The spectra show peaks at periods of 11 years, 1 year, 6 months and 27 days, which entails an important amplitude and phase modulation of the daily and semi-diurnal variation. No simple relationship between the peaks in the broad solar rotation band can be proposed.     

Empirical electron recombination coefficients in the D- and E-region

Effective electron recombination coefficients were deduced from measured ion production rates and plasma densities of 29 D-region rocket flights. They were grouped according to day and night conditions and arranged vs. ion production rate. Corresponding results from an ion-chemical model are presented for comparison.