Spatial interaction modeling of interregional commodity flows

Drawing from both the spatial price equilibrium theoretical framework and the empirical literature on spatial interaction modeling, this paper expands models of interregional commodity flows (CFs) by incorporating new variables and using a flexible Box-Cox functional form. The 1993 US commodity flows survey provides the empirical basis for estimating state-to-state flow models for 16 commodity groups over the 48 continental US states. The optimized Box-Cox specification proves to be superior to the multiplicative one in all cases, while selected variables provide new insights into the determinants of state-to-state CFs.     

Econometrically accounting for identities and restrictions in models of interregional migration

"Interregional demographic identities and other restrictions are explicitly taken into account in a simple time-series model of interregional migration. This goal is accomplished through the imposition of adding-up constraints on the estimated coefficients of a multi-equation linear system and by testing for homogeneity and symmetry. The pitfalls of utilizing the described procedures for migration analysis and forecasting are discussed. Full implementation of the technique is shown to require far more time-series observations on interregional migration than are commonly available."     

Estimation of commodity-by-commodity input–output matrices

In this paper we derive a method for the estimation of symmetric input–output tables (SIOTs), which makes it possible to use the commodity technology assumption even when use- and make tables are rectangular. The method also solves the problem of negative coefficients. In the empirical part we derive annual SIOTs in order to evaluate the differences between SIOTs calculated with different methods and the change in technical coefficients over time. Our results, based on data for Sweden, show that the impact of using different technology assumptions is rather large. However, in a factor content of trade application the impact of different technology assumptions does not seem to be very important. Also the size of the changes in the technical coefficients over time is found to be quite large, indicating the importance of calculating SIOTs annually.     

Patterns of dominant flows in the world trade web

The large-scale organization of the world economies is exhibiting increasing levels of local heterogeneity and global interdependency. Understanding the relation between local and global features calls for analytical tools able to uncover the global emerging organization of the international trade network. Here we analyze the world network of bilateral trade imbalances and characterize its overall flux organization, unraveling local and global high-flux pathways that define the backbone of the trade system. We develop a general procedure capable to progressively filter out in a consistent and quantitative way the dominant trade channels. This procedure is completely general and can be applied to any weighted network to detect the underlying structure of transport flows. The trade fluxes properties of the world trade web determine a ranking of trade partnerships that highlights global interdependencies, providing information not accessible by simple local analysis. The present work provides new quantitative tools for a dynamical approach to the propagation of economic crises.     

A family of square and rectangular interregional input-output tables and models

This paper formulates a large family of different square and rectangular (inter)regional input-output accounting frameworks. Most of the members of this family prove to have a consistent square or rectangular (inter)regional input-output model. Besides some disadvantages, the rectangular members prove to have important advantages over the square members of the family. Hence, it is concluded that the traditional dominance of the square format is unjustified. Moreover, the existence of a whole family implies that an explicit consideration of the choice of accounting framework is necessary. It is argued that, in making this choice, one should strive for an optimal and consistent mix between the assumptions made in the table construction phase and those made when building the corresponding model.     

Quadratic-mean-of-order-r indexes of output,input and productivity

Journal of Productivity Analysis - This paper deals with the quadratic-mean-of-order-r indexes of output, input and productivity. Each index is a family of indexes that unify many of the existing...     

Exchange rate sensitivity of US bilateral trade flows

The traditional way of assessing the impact of currency depreciation on the trade balance has been to estimate the elasticity of trade volume to relative prices. To this end, most previous studies used aggregate trade data. To avoid aggregation biases potentially hidden in aggregate data, recent studies have relied on bilateral trade data. Since import and export price data is not available on bilateral level, this study proposes an alternative way of assessing the impact of currency depreciation on bilateral trade flows. The models are applied between the US and her 19 industrial trading partners using recent advances in time-series modeling.     

Exchange rate volatility and Spanish-American commodity trade flows

A number of recent studies have tested the impact of exchange rate volatility on trade flows, particularly for individual commodities, for various country pairs. These have found that risk can increase as well as decrease trade, but that oftentimes industries are not affected. This study examines trade between the United States and Spain over the period from 1962 to 2009, for 131 U.S. export industries and 88 import industries. We find that exchange rate volatility has short-run and long-run effects in only a fraction of the cases, but that exports respond more to increased uncertainty than imports do. In all, only 35 of the 74 U.S. export industries are affected (11 positive, 24 negative), whilst only three out of 37 import industries have positive coefficients and 11 have negative ones. We find no evidence that durable or nondurable goods are more likely to respond to volatility, whilst small industries or specialized goods might show more of a positive response.     

Econometrically accounting for identities and restrictions in models of interregional migration: further thoughts

The authors reply to some comments concerning "specification, estimation, and hypothesis testing in models of interregional migration which are internally consistent." They also attempt to clarify some additional conceptual matters in these three areas.     

自动化立体仓库的出入库管理

对于自动化立体仓库实行科学的出/入库管理,可以帮助企业加快物流速度,提高生产效率,降低库存的资金占用,增强市场竞争力。     

Econometrically accounting for identities and restrictions in models of interregional migration : A comment

This comment clarifies and expands on an earlier article in this Journal by Greenwood and Hunt which addresses problems of estimating interregional migration models when non-stochastic adding-up constraints are present. The comment focuses on issues of specification, estimation and hypothesis testing within a closed system of migration equations stressing solutions to the degrees of freedom problem and tests for homogeneity and symmetry.     

Prices and factor demand in an endogenized input–output model

This paper combines factor demand functions (for intermediate input and labour) and price equations (derived from a Generalized Leontief cost function) with the traditional input–output price model. The cost functions determine factor demands for materials and labour as well as output prices at given input prices. At the second level of aggregation, the intermediate demand as a single input is split proportional to the elements in the column of the technical coefficients matrix. The emphasis in this endogenization of technical coefficients is on two features. First, the repercussion of output on input prices, and, second, the link between the econometric model for the supply side and the input–output demand model.     

Environmental responsibility and policy in a two-country dynamic input–output model

Increased spatial dependency of economic activities, as well as spatial differentiation of production and consumption, has implications for environmental policy. One of the issues that has gained importance is the responsibility for the emissions from products that cross national boundaries during the environmental policy's lifetime. This paper discusses the different ethical views of environmental responsibility. Furthermore, the policy measures that are associated with the different viewpoints are analyzed in a novel dynamic two-country two-sector dynamic input–output model. A numerical example is modeled to assess taxing schemes that are based on these ethical viewpoints. The results show that a tax on the ‘embodied’ environmental pressure, which is generally viewed as ethically preferable, is less effective that the current policy of taxing consumers of products. Our discussion however shows that these results are very dependent on the model structure and initial parameters that are used. Nevertheless, the model illustrates that policies that are based on ethically superior standpoints may have detrimental distortionary effects in the dynamic setting.     

Experimental designs for estimating plateau-type production functions and economically optimal input levels

Estimation of nitrogen response functions has a long history and yet there is still considerable uncertainty about how much nitrogen to apply to agricultural crops. Nitrogen recommendations are usually based on estimation of agronomic production functions that typically use data from designed experiments. Nitrogen experiments, for example, often use equally spaced levels of nitrogen. Past agronomic research is mostly supportive of plateau-type functional forms. The question addressed is if one is willing to accept a specific plateau-type functional form as the true model, what experimental design is the best to use for estimating the production function? The objective is to minimize the variance of the estimated expected profit maximizing level of input. Of particular interest is how well does the commonly used equally-spaced design perform in comparison to the optimal design. Mixed effects models for winter wheat (Triticum aestivium L.) yield are estimated for both Mitscherlich and linear plateau functions. With three design points, one should be high enough to be on the plateau and one should be at zero. The choice of the middle design point makes little difference over a wide range of values. The optimal middle design point is lower for the Mitscherlich functional form than it is for the plateau function. Equally spaced designs with more design points have a similar precision and thus the loss from using a nonoptimal experimental design is small.     

An expository critique of the Takayama—Judge models of interregional and intertemporal market equilibrium

In this paper an attempt is made to expound the spatial-temporal multi-product allocation and price equilibrium models originally proposed by Takayama and Judge (1971). Certain restrictive features of these models are highlighted and an alternative specification which overcomes these restrictions and replaces both the single and multiple storage period models of Takayama and Judge is outlined. The enhanced realism of this new model and its relatively simple structure should commend it to regional economists concerned with policy questions involving the production and distribution of a wide range of commodities.     

论职场成功之道

加入WTO后,特别是中共十六届三中全会后,中国各行各业的市场化速度正以超过人们想像的速度向前推进,所以,变革成了当今经济与管理活动的一种常态.这种加速的变革不但对人们衣食住行等日常生活等产生了深刻的影响,还对人们的思想观念、生活态度等产生了前所未有的冲击,这些又反过来深深地影响着中国整个社会的转型与变革的进程.     

On estimating dynamic factor demands

Many recent empirical studies on inter-related factor demands involve factor demand functions whose arguments depend on the researcher's arbitrary normalization rule. This paper shows how sensitive the estimated elasticities are to the various normalizations that are possible. Alternatives that are not dependent on a normalization are suggested.