bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Job Advertising Policies on Interregional Labor Migration
Authors: Amrhein Carl G.
Published: September 2010

A simulation model of a multiregional labor migration process is developed. Information about employment conditions in alternative regions is transmitted in a combination of three channels. The adopted emission policies directly control the amount of information available to potential migrants which, in turn, determines the potential migrant's perception of the level of welfare in the other regions. The effect of several different advertising policies on migration streams is examined. Employers can pursue a number of policies designed to maximize their return. Other agencies adopt policies that facilitate the matching process between unemployed workers and vacant jobs. Results are presented for a number of simulation experiments.
Dimensions of Spatial Price Dispersion Before and After the Crash of 1929
Authors: Clark Gordon L.
Published: September 2010

The spatial and temporal patterns of prices are analyzed over the 1919–40 period. Arguments are made for the distinctiveness of different economic episodes, including the crash of 1929, in terms of their local price effects. Nevertheless, it is also shown that the variability between cities and between components of their price series declined through the early 1940s. Alternative conceptions of spatial price systems are introduced, and due regard is also given to the structure and interpretation of city CPI data. Implications are drawn regarding the proper design of a theory that would explain the observed patterns of spatial price dispersion. This larger project is left, however, to another time.
Combining Nested and Linear Sampling for Determining the Scale and Form of Spatial Variation of Regionalized Variables
Authors: Oliver Margaret A. , Webster R.
Published: September 2010

The scale and pattern of variation of continuous spatial variables are often difficult to identify. The semi‐variogram of regionalized variable theory provides a precise solution once the approximate scale of spatial variation is known. The latter can be determined economically over several orders of magnitude by a nested analysis of variance where stages incorporate spatial scale. The method can become cumbersome if many stages are required, and an unbalanced design is described that enables many stages to be examined with a reasonable number of sampling points. The methods are illustrated with examples from a soil survey in the Midlands of England.
Measuring the Impact of External Economic Ownership
Authors: Jackson Randall W.
Published: September 2010

This paper presents a method by which issues associated with the impact of the corporate‐conglomerate structure on regional economic health and performance can be assessed. An alternative measure of the impact of external ownership based on intraregional commodity flows is introduced. A review of previous measures of external economic dominance with respect to the analysis of regional economic health and development is followed by a description of the new measurement method and directions for research application.
Toward Conceptualizing Trip‐Chaining Behavior: A Review
Authors: Thill Jean‐Claude , Thomas Isabelle
Published: September 2010

This paper critically reviews the existing literature on multiple‐trip journeys, and clarifies the need for an improved conceptualization and modeling strategy. It also suggests different ways that trip chaining can be treated and a theory constructed. Exploratory studies, from the 1960s and 1970s, are briefly surveyed (Section I). While they developed the existence and complexity of travel patterns, they lacked any comprehensive theoretical framework. However, they were useful in that they supported the conceptual framework of various kinds of stochastic processes used by transportation scientists to replicate trip‐chaining behavior (Section II). Scientists subsequently improved their conceptualization of the issue by grounding individual behavior on the principle of utility maximization. In this latter area the economists have emphasized theoretical concerns while transportation researchers have emphasized operationality (Section III).
Migration, Human Resource Transfers, and Development Contexts: A Logit Analysis of Venezuelan Data
Authors: Brown Lawrence A. , Kodras Janet E.
Published: September 2010

This paper is concerned with the reciprocal relationship between migration and development in Third World settings. Using individual‐level data for Venezuela, migration behavior is related to a person's age, educational attainment, gender, and characteristics of his/her place(s) of residence as an out‐migrant, in‐migrant, or stayer. Place characteristics are in terms of four groups based on employment patterns: the core, regional centers, resource frontiers, and traditional rural areas. Four questions are of concern. First, does development influence migration? All analyses indicate this is so. Second, does migration influence development? Findings are ambiguous in that places experiencing improvement in their mix of human capital lagged in the net number of persons obtained through migration whereas a gain in numbers was accompanied by deterioriation in human capital profiles. Third, was incipient polarization reversal occurring in Venezuela in the late 1960s, early 1970s? This paper departs from the usual approach by addressing this question in terms of human capital attributes instead of population aggregates. On this basis, polarization reversal is in evidence, particularly in regional centers. Finally, this study answers in the affirmative that places with different development characteristics generate migration streams differing in type, magnitude, explanation, and impact.
Recursive Algorithm for Determination of Proximal (Thiessen) Polygons in Any Metric Space
Authors: Mark David M.
Published: September 2010

A new and recursive algorithm for determining proximal polygons is based on quadtree concepts. The algorithm can use any distance metric, and produces a quadtree of the image of the proximal polygons. This can be converted to vector form, or be incorporated directly into a quadtree‐based geographic information system, in order to solve a number of closest‐point problems. The algorithm can also produce the Delaunay triangulation, which is the dual of the proximal polygons. Empirically, the running time of the algorithm is proportional to the number of centers raised to the 1.6 power.
The Statistical Modeling of Flow Data When the Poisson Assumption Is Violated
Authors: Davies Richard B. , Guy Clifford M.
Published: September 2010

The Poisson model typically provides a poor fit to flow data but more complex models are difficult to operationalize, especially with production or attraction constraints. Quasi‐ and pseudo‐likelihood approaches retain the attractive computational features of the Poisson model. A shopping model example suggests the latter approach to be preferable.
On the Fractal Measurement of Geographical Boundaries
Authors: Longley Paul A. , Batty Michael
Published: September 2010

This paper has two main objectives. First, we review and evaluate four different computational methods for measuring the “fractality” of cartographic lines: these are known as the structured walk, the equipaced polygon, the hybrid walk, and the cell count methods. Second, because previous research has restricted the focus of fractal measurement exercises to isolated physical entities, the subject of our empirical study concerns the urban area of Swindon, United Kingdom, that comprises a mosaic of contiguous land‐use parcels. In technical terms, the results pinpoint some of the comparative strengths and weaknesses of the four methods, whilst our substantive conclusion is that fractal dimension appears to be a function of both scale and land‐use type in our geographical study.
Coexistence and Separation of Two Residential Groups—An Interactional Spatial Dynamic Approach
Authors: Zhang Wei‐Bin
Published: September 2010

This paper is concerned with the spatial and temporal distribution of residents in an urban area. The residents are classified into two groups, that is, black and white, according to their characteristics. A dynamic model is built to explain how the residents are distributed over time and space. The model consisting of a set of partial differential equations is similar to competition‐diffusion equations in biology. We investigate conditions of coexistence and separation of the two groups.
A Geographical Product Differentiation Model of Trade Competition in Third Markets
Authors: Hanink Dean M.
Published: September 2010

Product differentiation trade models have been developed in order to account for some contemporary patterns of international trade that are inexplicable under the theory of comparative advantage. This paper presents the case for the geographical differentiation of products. A generalized geographical product differentiation model of trade competition in industrial third markets is outlined within a discrete choice framework. The model treats product price and quality, as determined by country of origin, as distinct variables in export competition. An indirect empirical test of the model's validity, using the cases of export competition between the United States and the Federal Republic of Germany and the United States and Japan, indicates that the generalized model is worthwhile in its ability to account for successful trade competition.
Asynchronous, Iterative, and Parallel Procedures for Solving the Weighted‐Region Least Cost Path Problem
Authors: Smith Terence R. , Peng Gao , Gahinet Pascal
Published: September 2010

A family of local, asynchronous, iterative, and parallel procedures (LAIPPs) are described. These procedures are designed to find least cost paths (LCPs) in bounded regions of the plane that have been partitioned into triangular subregions. The unit cost of traversing a given subregion is uniform within the subregion, but varies between subregions. In the case of one‐dimensional chains of triangles, the procedures are guaranteed to converge to a global LCP. Although the procedures are guaranteed to terminate, we have so far been unable to prove, in the general case of a two‐dimensional triangulation, that the procedures always terminate in admissible paths. Extensive experimental investigations, however, have revealed convergence to admissible paths in all cases examined. While counterexamples are constructed to prove that the procedures may converge to the local rather than global LCPs, convergence to the global LCP was found to occur in nearly all of our experimental investigations. The computational complexity of the procedures, as measured by the number of iterations required for convergence, was found experimentally to be independent of the size of the domain in which the paths lay, and to be slightly greater than linear in the Euclidian length of the paths. The complexity was also found to depend on the cost structure of the domain. Such LAIPPs appear to be promising procedures for both application and further investigation. In particular, the question of convergence is an interesting problem.
Dynamical Behavior of Cellular Automata under the Constraint of Neighborhood Coherence
Authors: Phipps Michel
Published: September 2010

The emergence of spatial discrete patterns has attracted little research interest among geographers, especially as far as the phenotypical aspects of the pattern are concerned. How can we understand the development of such patterns? What role is played by generative rules underlying this process? Using the cellular automata theory, a model (SISPAQ) was built to probe into the role of the neighborhood coherence principle (NCP) as a generative rule. Several remarkable properties of NCP are unveiled. A self‐organizing behavior is shown, which allows the system to counteract the maximum entropy law and build a pattern with a relatively high level of organization. Not only does NCP provide sufficient conditions for the building up of an organized pattern, but it also provides a self‐maintaining capacity. This is evidenced by the fact that under a critical value (the emancipation probability), any cell or group of cells displaying an aberrant state will be eradicated by a locally dominant state.
Spatial Aggregation of Complex Terrain
Authors: Band Lawrence E.
Published: September 2010

Distributed component simulations of watersheds seek to represent the terrain as a contiguous set of functional units such as hillslopes or subcatchments with distinctive hydrologic responses. The partition should capture the significant geographic patterns of watershed response by maximizing the proportion of the topographic and surface cover variance that exists between units and minimizing the proportion that exists within units. This has the effect of minimizing the effort of simulation that must be allocated to each drainage area. At the same time, the number of hillslopes should be limited to avoid too many consumptive model preparations and executions. The segmentation strategy may be guided and controlled by an understanding of the scale dependence of hillslope complexity, estimated by tracking the behavior of descriptive spherical statistics of the surface over a range of partition levels. Spherical statistics are used as they have strong bearing on the definition of uniform topographic facets, microenvironment, and the signal recorded by a remote sensor as influenced by the distribution of the surface normal. Digital terrain models are used to automate the partition of the watershed into different sets of hillslopes and for the computation of topographic complexity within and between units. The behavior of the surface variances over the range of sample scales is strongly related to the stream network structure and is expected to take on distinct forms that are characteristic of different geomorphic environments.
Classical Central Places as Protected Thresholds
Authors: Storbeck James E.
Published: September 2010

Previous research efforts demonstrate the use of location covering in the spatial structuring of central places within a single‐good context. In a multilevel context, this paper similarly develops a mathematical programming approach to the siting of central places based on the “protection” of inner (or threshold) markets. The objective function maximizes both market coverage of demand and market overlap, subject to an upper bound on market overlap; this allows the formation of different market structures consistent with the various K‐valued central place systems of Christaller and Lösch. Siting examples serve to illustrate the working of the protected threshold model in isotropic settings. Furthermore, ways in which the present model might be extended for other situations are examined.
The Regionally Constrained p‐Median Problem
Authors: Church Richard L.
Published: September 2010

In many applications involving the location of public facilities, the activity that is being located is added to the landscape of existing public facilities and services. Further, there also exists a political and behavioral landscape of differing jurisdictions, representations, and perceptions. This paper presents a new form of the p‐median problem which addresses two types of “regional” constraints that can arise in public facilities planning. A formulation is given for this specially constrained median problem along with a solution approach. Several examples are presented with computational results which indicate that this type of constrained problem could lead to better facilities planning.
Reducing Errors in Rainfall Estimates through Rain Gauge Location
Authors: Hogan Kathleen
Published: September 2010

Facility location models are examined as a framework for generating rain gauge networks designed to reduce errors in mean areal precipitation (MAP) estimation. Errors in estimating MAP may be divided into two types: (i) capture error, not observing a storm which occurs in a gauged area, and (ii) extrapolation error, using a rain gauge measurement to represent a heterogeneous area. In this paper, five rain gauge location models are developed to minimize these errors. The models include adaptations of the maximal covering location problem, the p‐median model, and three models derived from multicriteria cluster analysis. The models are tested using precipitation data from an experimental watershed maintained by the U.S. Department of Agriculture in Arizona. Analysis of the results reveals, for the particular watershed, that (1) in sparse networks, location of rain gauges can play a larger role than number of rain gauges in reducing errors in MAP estimates; (2) models based on mean hydrologic data provide nearly as good networks as models based on spatially correlated data; and (3) models yielding the best networks for estimating precipitation for flood predictions are different from the models providing the best precipitation estimates for low flow forecasts.
Analysis of Errors Due to Demand Data Aggregation in the Set Covering and Maximal Covering Location Problems
Authors: Current John R. , Schilling David A.
Published: September 2010

In this paper, we extend the concepts of demand data aggregation error to location problems involving coverage. These errors, which arise from losses in locational information, may lead to suboptimal location patterns. They are potentially more significant in covering problems than in p‐median problems because the distance metric is binary in covering problems. We examine the Hillsman and Rhoda (1978) Source A, B, and C errors, identify their coverage counterparts, and relate them to the cost and optimality errors that may result. Three rules are then presented which, when applied during data aggregation, will reduce these errors. The third rule will, in fact, eliminate all loss of locational information, but may also limit the amount of aggregation possible. Results of computational tests on a large‐scale problem are presented to demonstrate the performance of rule 3.
Joint Effects of Personal Factors and Ecological Variables on the Interprovincial Migration Pattern of Young Adults in Canada: A Nested Logit Analysis
Authors: Liaw Kao‐Lee
Published: September 2010

This paper applies a nested logit model to the 1981 census micro data to study the joint effects of personal factors (sex, mother tongue, nativity, education, and marital status) and ecological variables on the 1976–1981 interprovincial migration pattern of young adults in Canada. In multivariate contexts, personal factors not only are of paramount importance in explaining the departure process but also have significant interactions with ecological variables in determining the destination choice pattern.
Some Spatial Representation Problems in Disease Modeling
Authors: Thomas R. W.
Published: September 2010

The paper examines the applicability of spatial representation ideas to the determination of equilibrium solutions for multiregion disease models. In particular, alternatives to the standard specification of regionally variable infectivity rates are devised and their impact on the space‐time behavior of a carrier model for Hodgkin's disease is assessed using data for Greater Manchester.
Noninferior Bandwidth Line Simplification: Algorithm and Structural Analysis
Authors: Cromley Robert G. , Campbell Gerard M.
Published: September 2010

Digital line simplification operators are an important preprocessing component of a spatial data handling system. Simplification operators are used to generalize digital line files because these files are encoded at one scale but the objects they represent can be displayed at many other scales. Most line simplification algorithms are heuristics that caricaturize lines by eliminating points representing redundant data or conversely retaining the characteristic points of a line that have a high informational content. This paper presents a noninferior simplification algorithm that produces an optimal caricature of an encoded line with respect to the bandwidth criterion that all deleted points must be within a prespecified distance of the simplified line. Results show that it is a practical alternative to existing bandwidth heuristics.
Dimensional Variation Estimation: A Methodological Comparison
Authors: MacKay David B.
Published: September 2010

Estimation of the dimensional variation of points from data on the distances between pairs of points is a task common to several disciplines, disciplines which include behavioral geography, surveying, and cartography. Three methods for estimating dimensional variation are described and compared using an experiment involving simulated data and using empirical data from two studies, one based on distance judgments and the other based on direct coordinate judgments. The methods are shown to have different mathematical properties and to result in very different estimates.
The Assessment of Spatial Autocorrelation through Constrained Multiple Regression
Authors: Hubert Lawrence , Arabie Phipps
Published: September 2010

Most published measures of spatial autocorrelation (SA) can be recast as a (normalized) cross‐product statistic that indexes the degree of relationship between corresponding entries from two matrices—one specifying the spatial connections among a set ofnlocations, and the other reflecting a very explicit definition of similarity between the set of values on some variablexrealized over thenlocations. We first give a very brief sketch of the basic cross‐product approach to the evaluation of SA, and then generalize this strategy to include less restrictive specifications for the notion of similarity between the values onx.Using constrained multiple regression, the characterization of variate similarity basic to any assessment ofSAcan itself be framed according to the information present in the measure of spatial separation. These extensions obviate the inherent arbitrariness in howSAis usually evaluated, which now results from the requirement of a very restrictive definition of variate similarity before a cross‐product index can be obtained.
Substitutability, Spatial Structure, and Spatial Interaction
Authors: Lo Lucia
Published: September 2010

This paper attempts to distill the relationship among spatial structure, consumer preferences, and spatial interaction. It introduces the notion of substitutability. Destinations are substitutable in both economic‐behavioral and physical‐locational senses. Inadequate treatment of this can lead to variations in the estimated parameters of conventional spatial interaction models.
Bivariate Correlation with Spatial Data
Authors: Haining Robert
Published: September 2010

The paper examines the use of the Pearson product moment correlation coefficient and the Spearman rank correlation coefficient on map data that are spatially correlated. Research has shown that in this case standard estimators underestimate the true sampling variance of the Pearson coefficient. The Clifford and Richardson “effective sample size” solution to this problem is described, methods for implementing the procedure are considered, and properties of the technique examined. The method is also used to adjust the Spearman test. Two applications are given and the method of Clifford and Richardson contrasted with the method of data “prewhitening.”
A Structural Approach to the Form of the Population Density Function
Authors: Fisch Oscar
Published: September 2010

The central objective of this paper is to explore a comprehensive structural modeling approach that extracts analytical density functions answering questions raised by recent empirical studies.
Mode Choice in a Hub‐and‐Spoke Network: A Zero‐One Linear Programming Approach
Authors: O'Kelly M. E. , Lao Yong
Published: September 2010

While research has tackled the hub‐and‐spoke network design problem, that research has overlooked the air‐truck modal integration issue which is a common feature of real express delivery systems. This paper devises integer linear programs to represent the mode and route assignment aspects of the operational problem. The model is solved under four different levels of delivery schedule, and the results show that as the promised delivery schedule is relaxed, not only does the use of truck routes become more desirable, but also interesting adjustments in mode and hub assignment occur. Consider the case of hubs in Los Angeles and Dayton. As the time constraints are relaxed, cities such as Minneapolis and New Orleans originally linked by air to Los Angeles, switch to Dayton because cheaper truck routes become feasible.
Telecommunication Media Choice Behavior in Academia: An Austrian‐Swiss Comparison
Authors: Fischer Manfred M. , Maggi Rico , Rammer Christian
Published: September 2010

A general framework to analyze communication media choice behavior in the university setting is proposed which integrates a stated preference experimental design procedure into a discrete choice modeling framework. The framework is empirically tested using hypothetical choice experiments in which traditional mail, courier mail, telephone, facsimile, and electronic mail services were choice options to carry out information communication tasks. For this purpose face‐to‐face interviews were conducted in six universities in Austria and Switzerland. The choice modeling approach developed emphasizes the influence of communication context specific characteristics, individual and organizational characteristics of the communication initiator as well as the individual's perceptions and feelings about the communication media on the formation of preferences. Empirical results are presented using stated preference models of communication media choice behavior for a series of communication situations. Specific emphasis is laid on cross‐national differences in choice behavior.
Bayesian Regression and the Expansion Method
Authors: Casetti Emilio
Published: September 2010

This paper shows that within a Bayesian frame of reference the propensity to regard a model as invariant can be formalized into a prior probability density function of the parameters of an expanded formulation in which this model is encapsulated. The Bayesian approach allows to bring to the surface the implications of alternative levels of commitment to invariance assumptions on the results of empirical analyses, and can quantify the comparative strength of alternative drift specifications. The “expanded” Bayesian regressions are demonstrated by an example focusing upon the effectiveness of family planning.
Risk and Agricultural Land Use: A Reformulation of the Portfolio‐Theoretic Approach to the Analysis of a von Thünen Economy
Authors: Macmillan W. D.
Published: September 2010

This paper extends the portfolio‐theoretic approach to a von Thünen economy. It presents the farmer's decision problem as a mean‐variance mathematical program, then examines the effect of increasing risk or risk aversion on land use. Risk seeking and the effect of competition on risk taking are also considered.
Working, Shopping, and House Rents
Authors: Bacon Robert W.
Published: September 2010

The interaction between household demand for goods and for leisure and the supply of labor at various distances from an urban center is investigated for the case where rents are endogenous and adjust to equalize differences in utility produced by the greater time and money costs of the journey to shop and the journey to work. The model is solved for a set of realistic parameter values and this confirms that when rents are equal everywhere the demand for leisure can increase and the supply of labor decrease for households nearer the center, while once rents are endogenous the reverse must be true. For a household at a given location the elasticities of demand for goods and leisure and the elasticity of labor supply are calculated for all the parameters of the model. It is shown that the unavoidable costs of travel to work have strong effects on the rent gradient while the costs of the journey to shop have only weak effects, being offset by the variable frequency of shopping.
Why Do Suburban Offices Cluster?
Authors: Archer Wayne R. , Smith Marc T.
Published: September 2010

The clustering of suburban office space in “office parks,” as well as the larger activity nodes of polycentric cities, has been widespread in recent years. The reasons for this clustering are not well understood, as the footloose nature of firms suggests a variety of patterns might evolve. This paper explores three traditional explanations: economies of scale in the supply of space, demands for access, and face‐to‐face contact needs of firms. Finding that those explanations do not completely explain the clustering pattern, an alternative explanation is considered, the demand for image or prestige.
A Partitioning Model of Urban Retail Structure
Authors: Pipkin John S.
Published: September 2010

A model based on renewal theory generates the number of retail establishments in a place as the outcome of a competitive partitioning process. The available market, measured for example by population or by existing retail sales, is shared among businesses until no market potential market remains. Competing businesses obtain different shares of the market, and the number of establishments is predicted as a discrete random variable. Several alternative formulations are presented of varying generality. One version is successfully tested, using GLIM, on ten business types (SIC two‐digit classes) in 232 cities of New York State for 1977 and 1987. The model correctly predicts the form and the variance structure of the relationship between number of establishments and place size. It is shown how the model may be combined with models of city‐size distributions to predict aggregate frequency distributions of retail establishments across urban systems.
Testing for Regional Differences in Means: Distinguishing Inherent from Spurious Spatial Autocorrelation by Restricted Randomization
Authors: Sokal Robert R. , Oden Neal L. , Thomson Barbara A. , Kim Junhyong
Published: September 2010

Tests for differences among regional means are typically carried out by analysis of variance (ANOVA). When such data are spatially autocorrelated (SA), the assumptions of ANOVA are not met, giving rise to excessive type I error rates. Two spatially adjusted ANOVA methods, Griffith's and COCOPAN, have been proposed to overcome this problem. In this study we show, by means of extensive simulations, the magnitude of the error rates introduced by SA induced in isolation‐by‐distance models typical of those used in population genetics. For data suspected of exhibiting such SA, we propose a strategy for distinguishing between inherent SA, generated within the data by a contagious process, and spurious SA, introduced by regional differences in means. The approach adopted is that of restricted randomization of distance matrices. We also furnish error rates and power estimates for both Griffith's method and COCOPAN. In addition to the simulated data, the methods are applied to an actual example from plant population biology.
Requiem for the Fixed‐Transition‐Probability Migrant
Authors: Plane David A.
Published: September 2010

In a recent paper titled “Requiem for the Net Migrant” Andrei Rogers persuasively argues for the use of a multiregional perspective rather than a uniregional one in measuring and projecting the dynamics of internal migration. In particular, he highlights the deficiencies of using net migration rates in population projections, giving illustrations of the very large differences that can occur if constant net migration rates are assumed versus fixed interregional transition probabilities. Net migration rates are conceptually unsound because their denominators are not true “at‐risk” populations. Fixed interregional transition probabilities, however, are inconsistent with a sound behavioral representation of migration system dynamics. Whereas such stationary Markov models posit a role for shifting origin region populations, they do not embed the assumptions intrinsic to gravity or opportunity model concepts about the role of changing destination region populations. This paper explores alternative, more behaviorally pleasing interregional models that posit a role for shifting destination populations in altering the attractiveness of migration alternatives. Density‐dampened, destination‐population‐weighted transition probability structures are explored. The importance of modeling intraregional migration separately from nonmovement is stressed.
Telephone Communication Patterns in Austria: A Comparison of the IPFP‐based Graph‐Theoretic and the Intramax Approaches
Authors: Fischer Manfred M. , Essletzbichler Jürgen , Gassler Helmut , Trichtl Gerhard
Published: September 2010

Two alternative methodological approaches (the IPFP‐based and the intramax procedures) to the problem of pattern identification in spatial interaction data are compared and evaluated in this paper. After a general discussion of the major characteristics and shortcomings of these methodologies, the paper presents the findings of a case study relying on telecommunication data measured by the Austrian PTT in 1991, in terms of erlangs. The results clearly illustrate the superiority of the intramax approach in the context of medium‐sized and relatively centralized flow systems.
The Spatial Search Problem: Structure and Complexity
Authors: Maier Gunther
Published: September 2010

The paper discusses structure and complexity of the spatial search problem. From a set of assumptions it derives a rather general version of the spatial search problem and investigates some of its fundamental properties. Most importantly, the paper shows that the decision problem corresponding to the spatial search problem in this general version is NP‐complete.
The Encoding‐Error Model of Pathway Completion without Vision
Authors: Fujita Naofumi , Klatzky Roberta L. , Loomis Jack M. , Golledge Reginald G.
Published: September 2010

We present a model that accounts for errors in short‐cutting to complete a triangular pathway by individuals deprived of visual input. The model assumes that systematic error arises from components of navigation concerned with encoding an internal representation of the pathway, rather than the computation of a homeward trajectory or motor output per se. Subjects' tendency to compress the range of actually produced turns and distances, in comparison to the range of correct values, is attributed to regression toward the mean of encoded values during encoding of segments and turns, in the face of uncertainty about the actual values. Individual‐subject variations are attributed to differences in the encoding‐function parameters, not to variations in the processes themselves. The model provides excellent accounts of data obtained with triangular pathways but fares less well when pathway complexity increases, at which point errors do not appear to be solely attributable to encoding processes. The sources of error identified by the model are likely to play a role in navigation more generally.
Export Growth, Economic Growth, and Development Levels: An Empirical Analysis
Authors: Poon Jessie
Published: September 2010

The export‐promotion development strategy has been advocated as a generally valid prescription for economic growth on the basis of econometric studies of the exports‐growth relationships. A prominent shortcoming of these studies is in the presupposition, intrinsic to them, that exports‐growth relationships hold similarly for all developing countries. This paper tests the hypothesis that the exports‐growth relationships vary with the developing countries' level of development. My results indicate that high export growth is most beneficial to developing countries at intermediate stages of their development cycle, and consequently suggest that the export‐promotion development strategy is especially appropriate only for these countries.
Supply‐Side Urbanization? A Pooled Time Series Analysis
Authors: Berry Brian J. L.
Published: September 2010

Tests of Tolley's supply‐driven urban growth model for expanding sets of countries for time periods varying from 1831–1980 to 1951–1980 lead to its rejection in most contexts. The exception is for higher‐income market economies, where supply‐driven and demand‐driven determinants of urban growth are shown to alternate with long‐wave periodicity: During epochs of structural transformation following stagflation crises, supply‐driven determinants dominate; during periods of technological diffusion following deflationary depressions, demand factors come to the fore. But for middle‐ and low‐income nations, whatever the cross‐section and timespan, Tolley's hypothesis is not supported: Coefficients have the wrong sign, suggesting that urban growth is greatest when there are the greatest relative gains in rural productivity, but are statistically insignificant. The need is demonstrated for an urban growth theory that is substantially broader than normally has been modeled, with dynamics that are firmly grounded in an understanding of the periodic structure of economic macrohistory.
Contextualizing Welfare's Work Disincentive: The Case of Female‐headed Family Poverty
Authors: Kodras Janet E. , Jones John Paul , Falconer Karen F.
Published: September 2010

The conventional model of the relationship between welfare incentives and poverty rates holds that welfare payments produce an income‐enhancement effect that removes families from poverty until some threshold. Beyond this point increased payments engender a work‐disincentive effect resulting in increased rates of poverty. We challenge the model's assumption that poverty levels are a simple and spatially invariant response to welfare incentives, contending instead that local employment conditions may substantially alter the relation. Our reformulation of the conventional modeling approach is based on the expansion method. Specifically, we extend the model to include the effects of local labor‐market conditions on the response of poverty levels to welfare incentives. In contesting the invariance assumption, the expansion method allows us to determine where and in what contexts welfare is “work discouraging.” The empirical analysis, which is undertaken at the county level, indicates that welfare payments vary in their influence on poverty rates across different employment contexts. A national map portraying this parameter instability demonstrates that female‐family poverty rates are most responsive to welfare assistance in the rural South and least responsive in the metropolitan Northeast. Finally, we examine two sharply contrasting locales to illustrate how poverty is governed by specific employment and welfare characteristics.
An Assessment of the Space‐Time Differential Model for Aggregate Trip Behavior to Planned Suburban Shopping Centers
Authors: Baker Robert G. V.
Published: September 2010

Aggregate trip behavior to planned suburban shopping centers is studied in terms of changes in trip distance and shopping time within a framework of trip frequency, center scale, and consumer mobility. Such changes are expressed by a second‐order differential equation. The assumed shopping strategy is that consumers accelerate the shopping trip cycle by minimizing trip distances. This can be solved to provide theoretical norms to assess against an exploratory data set compiled from 2,810 surveys undertaken in 1980/82 and 1988/89 over a range of centers. The analysis shows a significant relationship between the gravity coefficient and trip frequency. The samples are tested for periodicity using Fourier analysis. The results show that “small” centers are more likely to exhibit periodic behavior. “Large” centers do not follow this hypothesis. Both the gravity coefficient and trip frequency are shown to be quadratic functions of center size. The nonlinearity may be introduced by the agglomeration of shopping opportunities at larger centers. A critical value for “small‐” and “large‐”center behavior is determined from the minimum points of these distributions. A second equation from classical diffusion analysis is tested for “large” center behavior, where consumers accelerate spatial choice through a time minimization strategy. The results suggest that this strategy occurs at the midrange specialty center during the afternoon of the pre‐Christmas rush rather than at large regional centers. The empirical characteristics of the three types of trip behavior are summarized.
Coastal Setback and the Impact of Water Amenities
Authors: Smith Bruce H.
Published: September 2010

This article analyzes the impact of a large water body—Lake Michigan—on residential property values using two models that incorporate a coastal “setback” term. The econometric results in both models strongly suggest that Lake Michigan and the setback width from the Lake significantly impact property values.
Place‐to‐Place Rent Comparisons among Canadian Cities
Authors: Miron John R.
Published: September 2010

This paper estimates average monthly gross rents for comparable rented private‐sector accommodation in Census Metropolitan Areas across Canada. By “gross rent” is meant the typical monthly payment in a CMA for a principal residence by a tenant of given traits under the conditions of a standard lease to a for‐profit landlord in competitive market equilibrium for premises used exclusively for accommodation, in an arm's length transaction, and includes heating and utility expenses where paid separately by the tenant. A single average gross rent is estimated for each city for dwellings and households, each with specified characteristics. This paper reviews the application of hedonic price models for this purpose, identifies shortcomings of current research in the field, and suggests a new form for such models. This new model is estimated using microlevel data from a sample of renter households taken across the twenty‐three largest urban areas in Canada. A classical version of the model is fitted first to renter data for individual cities, and its limitations assessed. A measure of “relative supply” is introduced to help explain city to city variations in the hedonic prices. Then an all‐city new model is estimated which incorporates relative supplies. This all‐city model is then used to derive place‐to‐place rent comparisons.
Statistical Analysis of the Distribution of Points on a Network
Authors: Okabe Atsuyuki , Yomono Hidehiko , Kitamura Masayuki
Published: September 2010

This paper shows four statistical methods that examine the distribution of points on a network (such as the distribution of retail stores along streets). The first statistical method is an extension of the nearest‐neighbor distance method (the Clark‐Evans statistic) defined on a plane to the method defined on a network. The second statistical method examines the effect of categorical attribute values of links (say, types of streets) on the distribution of activity points on a network. The third statistical method examines the effect of infrastructural elements (such as railway stations) on the distribution of activity points on a network. The fourth statistical method examines the compound effect of multiple kinds of infrastructural elements (say, railway stations and big parks) on the distribution of activity points on a network. These methods are discussed with empirical examples.
Geopolitical Force Fields
Authors: O'Sullivan Patrick
Published: September 2010

An entropy‐maximizing model of the geographic deployment of power by states is derived from a minimal set of assumptions about the system's operation. The outcome is a production‐constrained gravity model. This is manipulated to yield the general expression for the boundary between the spheres of influence of competing powers. Even in this simplest of forms, the model provides a logically consistent theoretical framework with which to view the outcomes of major geopolitical changes. The elaboration and disaggregation of the model to tackle finer adjustments would not be difficult.
Contingency, Realism, and the Expansion Method
Authors: Jones John Paul , Hanham Robert Q.
Published: September 2010

This paper examines the relationship between scientific realism and the expansion method. The frame of reference for our investigation is their joint conceptualization of “contingency.” We first explore the varied historical meanings of contingency; this is followed by a survey of its differential deployment within geographic thought. Attention then turns to theorizations of contingency in realism and the expansion method. The final portion of the paper assesses the potential for integrating these two analytic traditions within geographic research.
The Impact of Telecommuting on the Activity Spaces of Participants
Authors: Saxena Somitra , Mokhtarian Patricia L.
Published: September 2010

A spatial analysis of the activity spaces of telecommuters, based on the geocoded travel diary data from the State of California Telecommuting Pilot Project, is performed to analyze the impacts of telecommuting. The study analyzes the spatial location, orientation, and extent of the activity locations within the “activity spaces” of telecommuters and a nontelecommuting control group. To be able to quantitatively compare and contrast the travel patterns and the distribution of trip ends within the activity space, several spatial indicators have been defined. Several hypotheses concerning the selection of activity locations by individuals are presented and the impact of telecommuting on the selection of locations for activity is analyzed. Key findings include: on telecommuting days, 86 percent of telecommuters' activities are performed closer to home than to work, compared to 56 percent on normal commuting days; and destinations on telecommuting days are more evenly distributed in all directions around the home, whereas a majority of destinations on commuting days are oriented toward the work location.

To be able to understand the influence of the contributing factors toward the selection of nonwork activity locations, potential causal relationships between the influencing factors and the activity location choice are investigated. Several plausible log‐linear model structures for cross‐classified data provide a good fit to these relationships. Key results include: interaction effects of activity location with commute distance and with trip purpose are present in all the best‐fitting models, confirming the importance of these two variables in the selection of activity location; the interaction of activity location and income is also significant; and day status (telecommuting or not) of the employee influences the trip purpose, which in turn affects location.
Demographic Cycle Effects on Migration Timing and the Delayed Mobility Phenomenon
Authors: Pandit Kavita
Published: September 2010

This paper examines the effect of a cohort's size and position in the demographic cycle on the timing of migration during the young, labor force years. Previous literature has shown that demographic cycles are highly influential in determining the level of migration: migration propensities of young adults tend to be lower for large cohorts due to competitive labor markets and depressed job opportunities. This study argues that demographic cycles can also influence the timing of migration, and proposes a methodology that separates the examination of migration levels from that of migration timing. Analyses using Current Population Survey data show that members of small cohorts tend to move earlier on in their life cycle than members of large cohorts. Reconstructed age‐schedules of migration for large and small cohorts support the existence of “delayed mobility” among baby boomers.