46 research outputs found
Creating spatially-explicit lawn maps without classifying remotely-sensed imagery: The case of suburban Boston, Massachusetts, USA
Residential lawns are a dominant and growing feature of US residential landscapes, and the resource-intensive management of this landscape feature presents major potential risks to both humans and the environment. In recent years, scientists and policymakers have been increasingly calling for large-extent measures of lawns and other similar landscape features. Unfortunately, the production of such datasets using traditional, remotely sensed measurement approaches can be prohibitively expensive and time consuming. This study uses two statistical prediction methods to extrapolate the quantity and spatial distribution of residential lawns from a sample of mapped lawns in a large study area in suburban Boston, Massachusetts. The goal is to find an inexpensive, broad-coverage dataset that will provide useable estimates of landscape features in places where we do not have direct measurements of those landscape features. The first estimation method uses OLS regression in conjunction with the sample of mapped lawns and freely available US Census data representing theoretically informed social driver variables. The second, simpler, and less computationally intensive estimation method allocates the mean of the sample of mapped lawns uniformly across the study area. Both estimation methods are performed 1000 times in a Monte Carlo framework where the sample is drawn randomly each realization, to assess the sensitivity of the prediction results to the selection of CBGs in each simple random sample. The outputs of each estimation method are then compared to a reference map where the quantity and spatial allocation of lawns is known for each spatial unit of analysis. Results indicate that the OLS prediction method specified with the independent social driver variables performs better than a uniform prediction method when both are compared to the full-study area reference map
Multiobjective Programming with Related Bargaining Games: An Application to Utility Coal Conversions
A method is developed using n-person game theory together with multiple objective programming and is applied to aid-regional decisions on utility coal conversions. Converting oil fired electric utilities to coal is seen as being of great strategic importance. There are, however, many impediments to utility coal conversions including costs and environmental restrictions. The method developed is used to find workable solutions to this problem which are evaluated based upon measures of economic efficiency, environmental degradation and distributive equity. Using these methods, policy makers, planners and administrators can determine solutions that will aid in the resolution of regional conflicts. Ā© 1983
Trust, Transactions, and Information Technologies in the U.S. Logistics Industry
How does information technology (IT) alter the organizational dynamics in an industry? In this article, we examine changes in competition and interfirm relations in the U.S. logistics industry, particularly whether trust-based interfirm relationships are being substituted by competition-based relationships and the rationale for outsourcing. We also examine how new IT tools and outsourcing interact and bow logistics contracts, the size of firms, and knowledge lead to integration or disintegration within the industry. The results of our research demonstrate that while the use of IT tools is widespread, traditional trust-based relationships exhibit a considerable resilience in the logistics industry. The industry is also undergoing a complex process of restructuring in response to technological change, on the one hand, and the persistence of geographic and functional specialization, on the other hand. The industrys focus on the delivery of high-quality services, coupled with excess capacity in the industry in the past few years, has contributed to these contradictory trends. As a result, elimination of the middleman has not been as widely observed as expected. Ā© 2007 Clark University
A Mixed Integer and Multiple Objective Programming Model to Analyze Coal Handling in New England
Mandated electric generation coal conversions in New England could place a severe strain on the coal handling and transportation facilities in New England ports. This paper presents an analytical scheme leading to the development of optimal plans for the reuse and redevelopment of marine transport networks in New England. Utilizing the port inventory that provides information on existing coal handling facilities and the capability of the ports to increase capacity of existing facilities or locating new facilities, a mathematical programming model is used to determine the optimal capacity, placement and railrod and marine interface of coal handling facilities within and between the New England ports and converting power plants. Initially a mixed integer programming model with a least cost objective is formulated. It is then expanded to a multiobjective programming problem in order to provide information to the port planners and decision makers on the tradeoffs between the costs and temporal efficiency of coal transporation and handling for various locational configurations. Ā© 1983
Integrating a Raster Geographical Information System with Multi-Objective Land Allocation Optimization for Conservation Reserve Design
The multi-objective land allocation problem is to optimize the selection of land for different uses based on a set of decision objectives. For most applications, a geographical information system (GIS) is either absent or loosely coupled through file exchange. In this article the evolutionary algorithm (EA), a heuristic solution method for optimization problems, is integrated with a raster GIS to form a spatial decision support system (SDSS) for multi-objective conservation reserve design. The SDSS effectively combines the functions of a GIS for data management, analysis, and visualization, with the optimization capability of the EA; and provides a uniform way to solve conservation reserve design problems with different types of constraints and objectives. The SDSS is demonstrated through application to the creation of conservation reserves in Bolivia to protect 17 endemic mammals
A Dynamic LocationāAllocation Model for Evaluating the Spatial Impacts for JustāināTime Planning
This paper presents an interperiod network storage locationāallocation (INSLA) model to solve the justāinātime production planning problem. The model is extended to a multiobjective problem in which tradeāoffs between delivery time and transportation costs are analyzed. The results for a hypothetical problem show that in an attempt to reduce inventories on the part of the primary purchaser of raw materials, the possibility exists for less than optimal behavior in the system. 1990 The Ohio State Universit
Optimizing Freight Transshipments: An Evaluation of East Coast Coal Export Options
Many factors will determine the extent to which the U.S. will be a significant supplier of coal to world markets. Important among these factors is the ability of the domestic coal transport system to move coal from mines to export ports and the capability of these ports to efficiently transship the coal to export markets. This paper describes the use of a mixed-integer mathematical programming model, called the Coal Logistics System (COLS), to provide information for transportation infrastructure planning with regard to increasing U.S. coal exports. COLS is a comprehensive coal transportation model that includes the location and activity levels for coal handling technology. It is used in this study to evaluate potential patterns of export coal movements in the Eastern U.S. with respect to transportation costs, optimal location and activity levels for port coal handling facilities and related investment expenditures. Ā© 1983
A Note on Estimating a Long-Run Average Cost Curve for Flue Gas Desulfurization
This paper presents the estimation of a long-run average cost curve for the flue gas desulfurization of coal-fired electric generating plants. Long-run average costs are shown to decline asymptotically with the level of sulfur dioxide removal and to decline with the sulfur content of the coal burned. Ā© 1988