Competing destinations and intervening opportunities interaction models of inter-city telecommunication flows

This research makes use of a large sample (600,000) of individual telephone calls between local exchanges (cities, villages) within a U.S. region. Callers and callees are identified by their 4-digit SIC (Standard Industrial Classification) code. The intersectoral and interlocational flows (number of messages and conversation minutes) are aggregated into major economic sectors (Agriculture, Manufacturing, Retail Trade ...., and Households), and are analyzed by estimating, in a simultaneous equation framework, spatial interaction models that account for (1) the role of the spatial structure, which reflects the competition and agglomeration effects that take place among the flow destinations, and (2) the role of the reverse flows, which reflect the process of information creation necessary to complete intersectoral economic transactions. A particular focus is set on Fotheringham's competing destinations model and Stoufer's intervening opportunities model, while accounting for the effects of place hierarchy. A theoretical framework is presented, to guide the interpretation of the empirical results and their policy implications regarding the impacts of telecommunications deregulation, transportation and telecommunications interactions, and the role of information technologies in fostering the development of rural and peripheral areas.

Multi-Objective Programming for the Allocation of Trans-Boundary Water Resources - the Case of the Euphrates and Tigris

The allocation of water in a multi-country river system necessarily involves conflicting objectives, where increasing water benefits to one country may entail losses to other countries. This paper presents the formulation and application of a multi-objective linear programming model, where each objective represents the benefits to a country from using water for agricultural, municipal, and energy uses, net of conveyance costs. This model extends the Euphrates and Tigris River Basin Model (ETRBM), presented in Kucukmehmetoglu and Guldmann (2004), with the three objective functions representing the net water benefits to the three riparian countries – Turkey, Syria, and Iraq. The model is used to delineate the set of non-inferior solutions (Pareto frontiers), where no individual country benefit can be increased without reducing the benefits of at least another country. These Pareto frontiers, and the underlying water resources allocations, are graphically displayed and analyzed under different scenarios related to river flow, electricity price, and agricultural productivity. The trade-offs between the three benefits are assessed, providing the basis for possible compromises among the three countries. Potential policy implications for trans-boundary water resources utilization are discussed.

International water resources allocation and conflicts - the case of the Euphrates and the Tigris

The Mesopotamia region, within the boundaries of Turkey, Iraq, and Syria, is populated by different ethnic, national, and religious groups (Turks, Arabs, Kurds, Sunnis and Shiites), which have long fought over the control of its fertile lands. Since the early 1970's, there has been an increase in tension among these three countries, primarily related to the sharing of the waters of the Euphrates and Tigris rivers. In particular, Turkey's development of Southeastern Anatolia, with water needed for agricultural and energy production projects, has been viewed as a threat to the well-being of Syria and Iraq. This water problem is likely to be exacerbated in the future, when water demand grows in both quantity and quality due to high population growth and urban development. This paper presents a water allocation optimization model, that represents, in network form, the system made of the two rivers and their various consumption (agriculture, urban centers, hydropower plants) and transshipment nodes, including the possibility of transferring water from the Euphrates to the Tigris. The basic model maximizes the aggregate net benefits of the three countries, including the gross benefits from water uses in agriculture, urban functions, and hydroelectricity, minus the costs of water conveyance. The model is formulated as a linear program, and accounts for both evaporation and return flows from consumptive uses. In view of the uncertainty surrounding the values of several parameters (e.g., agricultural benefit derived from using a gallon of water), the model is first used to carry systematic sensitivity analyses to identify the critical parameters. Next, the model is used to generate the net benefit Pareto surface, using multi-objective programming techniques. The systematic analysis of this surface provide information about the benefit trade-offs between any two countries. Finally, cooperative game theory concepts (core, Shapley value, nucleolus) are used to identify stable water allocations, where all three countries find it beneficial to cooperate. These various analyses are carried out under different scenarios related to future energy prices, agricultural production efficiency, and total water availability. The policy implications of the results are discussed, and areas for further research are outlined.

Spatial interaction modeling of interregional commodity flows

Understanding the determinants of interregional commodity flows is critical for both transportation infrastructure planning (highways, railroad tracks, river/port facilities) and regional development policies (location of activities, reducing regional disparities). Unfortunately, limited data availability has, in the past, hindered empirical research in this area. Drawing from both the spatial price equilibrium theoretical framework and the empirical literature on spatial interaction modeling and international trade, this paper expands past spatial interaction models of commodity flows by incorporating new variables into the model, using a flexible Box-Cox functional form, and applying the analysis to all manufacturing commodities. The recently released 1993 U.S. Commodity Flows Survey provides the empirical basis for estimating state-to-state flow models for 16 commodity groups over the 48 continental U.S. states. Based on input-output considerations and in order to differentiate intermediate from final commodity demands, the new variables include more detailed descriptions of the economies of the origin and destination states, such as employment and value added for the commodity sector at the origin state, wholesale employment at both ends, manufacturing employment at the destination state, and population and per-capita income at both ends. In addition, the average establishment size for the commodity at the origin is intended to measure scale or diversification effects. The competitive or agglomerative effects of the economic spatial structure are captured with competing destination and intervening opportunities variables. In addition to the average hauling distance between states, the model includes dummy variables measuring whether (1) having a common physical border, and (2) the origin or destination states being custom districts, have an effect on flows. Overall, the results show that the selected variables and functional form are very successful in explaining flow variations. The optimized Box-Cox specification proves to be superior to the log-log one in all cases. The results include the following findings: (1) the distance effect is negative and highly significant, with bulkier products hauled over shorter distances; (2) the adjacency effect is significant, with neighboring states trading more with one another, even after accounting for distance; (3) the impact of the spatial structure is of the competitive type in most cases; (4) the effects of imports and exports are significant for specific commodities; (5) wholesale activities at both origins and destinations are important facilitators of commodity flows; (6) except in one case (furniture), flows increase with product diversification; and (7) the role of intermediate and final demands for the commodities are clearly reflected by the selected employment, population and per-capita income variables. Various areas for further research are outlined.

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

Retail location and urban resilience: towards a new framework for retail policy

This article reviews the literature on the interactions between retail activities and urban economic resilience with a primary focus on the U.S. The social, economic and environmental impacts of large-scale retail outlets on existing retail and urban systems and their sustainability have been extensively discussed in the urban planning literature. However, the survival of retail venues as a major land use, in a competitive, dynamic urban environment, has been discussed less. In particular, the adjustment of traditional city-center retailers facing an influx of new shopping venues is a timely issue. The literature offers a wide range of examples, from their disappearance to their role in the successful revitalization, vitality and viability of city centers, and their increased economic resilience. At the same time, the number of dead malls has been increasing in developed and developing countries, and in particular in the U.S., showing that large-scale shopping venues also need strategies for adaptation and change. This review explores the issues and policies that have altered urban dynamics in favor of traditional retailers and contributed to their resilience, identifies the role of the public sector in supporting city center revitalization, and develops a framework for the effective integration of retail planning into urban policy to enhance urban economic resilience

The Urban-Rural Telecommunications Divide Endures: A Historical Perspective from Landline Telephony

The popular press and academic literature show that the urban-rural divide persists with regard to recent telecommunications technologies, such as broadband and wireless service. As was the case for landline telephony, this lack of deployment in rural areas is rooted in cost differentials and lack of agglomeration economies. This paper provides historical insights on this divide, using 1990 data on voice communications in a region located in the northeastern United States, and investigates (1) whether there are differences in telecommunications usage between urban and rural firms, (2) whether advanced telecommunications technologies provide an economic advantage to rural firms, and (3) what are the factors encouraging and inhibiting the provision of these technologies in rural areas. Exchange-level data on telephone usage by eleven economic sectors are first linked, through regression analysis, to data characterizing the exchange employment, rural character, availability of advanced technology, and geography. Rural activities turn out to use telecommunications less than urban ones in the absence of advanced technologies, but the latter tend to significantly increase usage. Next, a logit model is estimated to link the deployment of one advanced technology—digital switching—to market and geographical variables. The results tend to support the idea that an advanced telecommunications infrastructure in rural areas may be important to attract activities that make heavy use of telecommunications, but also that its provision is inhibited by the traditional rural barriers of distance and low population density