Market analysis and transportation procurement for food aid in Ethiopia

Empirical research characterizing transportation markets in developing countries is scarce. By analyzing contracts between the World Food Programme and private carriers, we identify the determinants of transportation tariffs in Ethiopia and quantify their relative importance. The econometric models devised from our unique dataset provide insights for shippers to improve procurement processes, for carriers to develop competitive business models and for government authorities to define effective investments and policies. Results indicate that the number of carriers on a given lane significantly reduces transportation tariffs and that policies stimulating competition may be as important as road infrastructure investments in Ethiopia's development strategy.     

Infrastructure and Performance of the Italian Economic System

This paper aims to analyze the consequences for the Italian economy of the recently started process of modernization and extension of the country's infrastructure. The planned measures are expected to increase the competitiveness of Italian businesses, and to improve the quality of life. In the short term, investments in infrastructure will increase the construction sector's production and, consequently, activate income and employment multipliers. The Italian economic system being highly differentiated from a territorial viewpoint, the impact of new investments on its economic system has been analyzed by means of a biregional model that accounts for the peculiar productive structure of the 20 Italian regions.     

Increasing the length of parents' birth-related leave: The effect on children's long-term educational outcomes

Investments in children are generally seen as investments in the future economy. In this study I focus on time investments in children as I investigate the long-term educational effects on children of increasing parents' birth-related leave from 14 to 20 weeks using a natural experiment from 1984 in Denmark. The causal effect of the reform is identified using regression discontinuity design to compare a population sample of children born shortly before and shortly after the reform took effect. Results indicate that increasing parents' access to birth-related leave has no measurable effect on children's long-term educational outcomes. Mothers' incomes and career opportunities are slightly positively affected by the reform.     

攀枝花城市基础设施水平评价研究

攀枝花作为典型的转型期资源型城市,经济快速发展的进程中,资源开发与城市规划建设矛盾突出。本文通过统计综合分析,从时间发展上,对攀枝花2002-2011年的城市基础设施水平发展趋势进行分析,并对攀枝花城市基础设施水平与固定资产投资额做相关性分析;采用聚类分析法分析攀枝花的城市基础设施水平在全省的分类情况;从空间分布上,对攀枝花2011年各区县的基础设施水平进行分析。结果表明攀枝花基础设施水平总体呈稳步上升趋势,基础设施水平稳定,但2009年后开始下降,区县水平差异较大;建议适当加大基础设施建设力度,同时加强道路设施建设,加大县城投资比例。     

基础设施投资的空间溢出效应分析——以沪昆线沿线城市为例

以沪昆铁路沿线区域及城市经济发展为分析对象,实证分析了我国基础设施投资的空间溢出效应。认为沪昆线的基础设施投资既产生了提高沿线区域及城市的运输能力、扩大沿线贸易量、调整沿线产业结构、促进沿线经济增长的空间正溢出效应,也产生了加剧沿线地区及城市要素的非均衡流动、非均衡经济增长的空间负溢出效应。     

A model for identifying and ranking dangerous accident locations: a case study in Flanders

These days, road safety has become a major concern in most modern societies. In this respect, the determination of road locations that are more dangerous than others (black spots or also called sites with promise) can help in better scheduling road safety policies. The present paper proposes a multivariate model to identify and rank sites according to their total expected cost to the society. Bayesian estimation of the model via a Markov Chain Monte Carlo approach is discussed in this paper. To illustrate the proposed model, accident data from 23,184 accident locations in Flanders (Belgium) are used and a cost function proposed by the European Transport Safety Council is adopted to illustrate the model. It is shown in the paper that the model produces insightful results that can help policy makers in prioritizing road infrastructure investments.     

区域间公共基础设施溢出效应研究

运用中国各省(市、自治区)1990-2008年的面板数据,通过建立空间计量模型,对区域问基础设施投资的空间外溢性进行检验.研究结果显示.公共基础设施投资对区域经济的增长不仅在本区域内具有外部溢出效应,在区域间也存在显著的外部溢出效应.这表明莱一地区的公共基础设施投入不仅可以提升本地区的产出,也会对相邻区域的经济增长产生...     

Unlocking the potential of advanced manufacturing technologies

This research examines whether investments in advanced manufacturing technologies (AMTs) such as flexible manufacturing systems (FMS), computer aided design (CAD), computer aided manufacturing (CAM), robotics, etc., are more likely to lead to improved performance if they are supported by improvements in the manufacturing infrastructure of the company. This question is evaluated using data gathered from 202 manufacturing plants chosen from industries generally considered to have relatively high investments in technology.Multiple item scales are developed and adapted from sources in the literature to measure investments in technology, infrastructure, and the performance of the plant. Evidence supporting the reliability and validity of these scales is provided. Hierarchical regression is used to analyze the relationship between technology, infrastructure, and performance. The results suggest that there is an important interaction between the adoption of advanced manufacturing technologies and investments in infrastructure. Firms that invest in both AMTs and infrastructure perform better than firms which only invest in one or the other. Separate analyses on sub-samples of firms with the highest and lowest investments in AMTs show that infrastructural investments have a stronger relationship with performance in the high investment group. Thus, the data indicate that infrastructural investments provide a key to unlocking the potential of advanced manufacturing technologies.     

土地一级开发中储备土地出让价格影响研究——以武汉市后湖地区为例

研究目的为了解武汉市后湖地区土地一级开发中基础设施投入对土地产出效益的影响,为政府的投资决策提供参考。研究方法为层次分析法和经济学研究方法。研究结果为（1）土地储备中道路设施投入对土地价格的影响最显著,权重系数为0．211;（2）随着道路设施投入的增加,土地产出效益呈先递增后递减的趋势,其影响路径符合边际报酬递减规律。研究结论为在土地一级开发中应注重道路等基础设施的投入,同时要遵循边际报酬递减规律,减少投入的盲目性,避免粗放的经营发展方式,进而控制土地储备成本,提高土地的投入产出效率。     

Bayesian inference in a correlated random coefficients model: Modeling causal effect heterogeneity with an application to heterogeneous returns to schooling

We consider the problem of causal effect heterogeneity from a Bayesian point of view. This is accomplished by introducing a three-equation system, similar in spirit to the work of Heckman and Vytlacil (1998), describing the joint determination of a scalar outcome, an endogenous “treatment” variable, and an individual-specific causal return to that treatment. We describe a Bayesian posterior simulator for fitting this model which recovers far more than the average causal effect in the population, the object which has been the focus of most previous work. Parameter identification and generalized methods for flexibly modeling the outcome and return heterogeneity distributions are also discussed.Combining data sets from High School and Beyond (HSB) and the 1980 Census, we illustrate our methods in practice and investigate heterogeneity in returns to education. Our analysis decomposes the impact of key HSB covariates on log wages into three parts: a “direct” effect and two separate indirect effects through educational attainment and returns to education. Our results strongly suggest that the quantity of schooling attained is determined, at least in part, by the individual’s own return to education. Specifically, a one percentage point increase in the return to schooling parameter is associated with the receipt of (approximately) 0.14 more years of schooling. Furthermore, when we control for variation in returns to education across individuals, we find no difference in predicted schooling levels for men and women. However, women are predicted to attain approximately 1/4 of a year more schooling than men on average as a result of higher rates of return to investments in education.     

The impact of vertical integration on inventory turnover and operating performance

This paper investigates how vertical integration may influence inventory turnover and firm operating performance. A causal model is developed to investigate the effects of vertical integration on three types of inventory, namely raw materials inventory (RMI), work in progress inventory (WIPI) and finished goods inventory (FGI). The model tests the interactions between inventory types and the consequences of inventory turnover performance on various aspects of firm performance including costs and profitability. In particular, path analysis supports systematic differences with respect to how vertical integration affects RMI, WIPI and FGI. Vertical integration has a positive effect on RMI and FGI turnover but no significant effect on WIPI turnover. FGI contributes to a reduction in supporting processes costs which causes an improvement in return on sales (ROSs). Vertical integration impacts ROS directly.     

从“招商引资”到“内培外引”促昆明和谐发展

招商引资,改善了昆明的基础设施,优化了昆明的环境。通过招商引资,昆明在城市形象提升、资金吸纳、产业结构调整、促进就业等方面都取得了长足进展。昆明彰显出建设面向西南开放重要桥头堡的优势。然而,在招商引资过程中也出现了"招来女婿赶走儿"的现象,因此,昆明着力改进招商引资模式,实行"内培外引"模式促进本土企业"二次创业";促进昆明经济和谐发展。     

Institutions and public investment: an empirical analysis

This paper investigates the effect of institutional quality on the levels, volatility and quality of public investment. Our findings suggest an inverse relationship between public investment levels and institutional quality, supporting the idea that governments use public investment as a vehicle for rent seeking. We also find that lower quality of governance increases the volatility of public investment. Finally, we provide some tentative evidence of a positive relationship between institutional quality and the quality of infrastructure. Policymakers who aim to reduce infrastructure needs through capital spending should take measures to strengthen institutional capacity to manage public investments.     

A financial accelerator in the business sector of a macroeconometric model of a small open economy

We have incorporated a financial accelerator mechanism operating through investments in the business sector in a dynamic macroeconometric model of the Norwegian economy. In this new and amended model aggregated credit and equity prices are determined simultaneously in a system characterized by a two-directional contemporaneous causal link, which has been designed and estimated by a new procedure for simultaneous structural model design. Combined with a mechanism where credit and asset prices are mutually influenced by real investments, this creates a financial accelerator amplified by a credit-asset price spiral. Simulations illustrate how the introduction of a financial accelerator significantly reinforces and extends the economic cycles in projections and forecasts, in particular when confronted by a severe shock. Furthermore, monetary policy has a markedly stronger effect in the short and medium term, while the impact of fiscal policy is affected to a relatively small degree as it is more remotely linked to financial markets.     

Debt financing and maintenance expenditure: Theory and evidence on government-operated toll roads in China

Transportation infrastructure is the foundation of economic growth, and the existence of high-quality roads is inseparable from their durable maintenance. However, the burden of heavy debt has brought risks to maintenance management and distorted resource allocation. This study builds a two-stage optimal theoretical model under different debt-financing constraints in China, who has the longest expressway mileage of any country in the world. We establish the two principles of “spend-and-debt” and “debt-and-spend” to demonstrate the substitution effect and the complementary effect of debt financing on maintenance, respectively. Furthermore, we use a time-varying differences-in-differences approach to estimate the effect of the financing of tollway bonds on maintenance and further discuss the mechanism. The results provide evidence that there is a significant improvement in the relationship between tollway bonds and maintenance expenditure, mainly due to the reduction of debt costs and the passive propelling of the government’s spending responsibility. Our proposed theoretical and empirical framework sheds new light on transportation infrastructure research. More specifically, the impetus for public expenditure comes from a decrease of the substitution effect, which not only alleviates the burden of debt scale on the public sector but also provides a reference for developing countries to balance infrastructure construction and maintenance.     

Urban spatial structure,suburbanization and transportation in Barcelona

I investigate the effect of improvements to the transportation infrastructure on changes in location patterns of population in Barcelona, Spain between 1991 and 2006. At a census tract level, I verify and extend the finding of Baum-Snow (2007a) that transportation improvements cause suburbanization: (1) improvements to the highway and railroad systems foster population growth in suburban areas; (2) the transit system also affects the location of population inside the central business district (CBD). To estimate the causal relationship between the growth of population (density) and transportation improvements, I rely on an instrumental variables estimation that uses distances to the nearest Roman road, the nearest 19th century main road, and the nearest 19th century railroad network as instruments for the 1991–2001 changes in distance to the nearest highway ramp and the distance to the nearest railroad station.     

三维植被网在高速公路边坡防护中的应用浅析

边坡坡面防护是现代土木建设的一项重要工程。随着我国公路、铁路和水利等交通基础设施建设的迅猛发展,如何对公路、铁路路基的边坡坡面进行有效的防护,具有重大的工程意义和经济意义。三维植被网作为一种新型的坡面防护材料,具有很好的使用性能和推广价值。本文详细介绍了其特点、优点以及施工工艺。     

路桥工程中钢纤维混凝土的具体应用

随着我国市场经济的发展,城市化建设进程的加快,我国的基础设施建设逐渐增多,公路和桥梁工程的建设日益增加,路桥工程对于建筑材料的要求越来越高,钢纤维混凝土作为一种新型的复合材料,可以有效提升建筑混凝土的拉伸,弯曲和抗冲击的性能。本文简单概述了钢纤维混凝土的基本概念和基本性能,深入探讨了钢纤维混凝土在路桥工程中的具体应用,并简要介绍了钢纤维混凝土的施工工艺,以便参考。     

Network Effects and Infrastructure Productivity in Developing Countries*

This study proposes to investigate the threshold effects in the productivity of infrastructure investment in developing countries. It concludes to their presence in the relationship between output and private and public inputs as well as network effects in the productivity of infrastructure. When the available stock of infrastructure is low, investment has the same productivity as non‐infrastructure investment. On the contrary, when a minimum network is available, the marginal productivity of infrastructure investment is greater than the productivity of other investments. Finally, when the main network is achieved, its marginal productivity becomes similar to the productivity of other investment.     

Dynamic appraisal of infrastructure investments

The assessment of the reciprocal impacts of infrastructure investments and their socio-economic environment requires that a number of such aspects be simultaneously considered. Some of those aspects, however, have not been traditionally incorporated in such assessments due (in part) to the limitations inherent in the techniques utilized in current practice. This paper presents a conceptual framework for the use of dynamic simulation in the assessment of packages of infrastructure investments. The concepts are then applied to case studies involving the evaluation of coordinated sets of infrastructure projects in rural areas.