bluuebunny/crossref_metadata_2025 huggingface dataset:
Early-Life Seizures and Cognitive Impairment: A Spiny Problem?
Authors: Stafstrom Carl E. , Benke Timothy A.
Published: September 2010

Recurrent Seizures and the Molecular Maturation of Hippocampal and Neocortical Glutamatergic Synapses. Swann JW, Le JT, Lee CL. Dev Neurosci 2007;29( 1 – 2 ):168–178. Recurrent seizures in animal models of early-onset epilepsy have been shown to produce deficits in spatial learning and memory. While neuronal loss does not appear to underlie these effects, dendritic spine loss has been shown to occur. In experiments reported here, seizures induced either by tetanus toxin or flurothyl during the second postnatal week were found to reduce the expression of NMDA receptor subunits in both the hippocampus and neocortex. Most experiments focused on alterations in the expression of the NR2A subunit and its associated scaffolding protein, PSD95, since their expression is developmentally regulated. Results suggest that the depression in expression can be delayed by at least 5 days but persists for at least 3–4 weeks. These effects were dependent on the number of seizures experienced, and were not observed when seizures were induced in adult mice. Taken together, the results suggest that recurrent seizures in infancy may interrupt synapse maturation and produce persistent decreases in molecular markers for glutamatergic synapses - particularly components of the NMDA receptor complex implicated in learning and memory.
Some New Methods of Topologic Classification of Channel Networks
Authors: Werner C. , Smart J. S.
Published: September 2010

Some new methods for the topologic classification of channel networks are proposed. These methods are all based on the concept of topologic path length, or number of links from the network outlet to a junction or source. Two parameters, the total path length (sum of all path lengths) and the diameter (largest path length) are shown to be useful in network analysis. Some advantages of these parameters are that they are easy to measure, have straightforward topologic interpretations, and are closely related to important geometric measures. Moreover, they are capable of explaining various empirical geomorphic “laws,” such as the 0.6 power relation between mainstream length and area.
A Model to Relate the Size of the Central Business District to the Population of a City
Authors: Briggs Ronald
Published: September 2010

A set of dynamic models of CBD growth are developed. They hypothesize that growth rates depend upon the population growth rate together with the increasing unwillingness of people to travel to the city center as city size increases. A prediction of the model is that absolute decreases in CBD size can occur associated simply with population growth rather than technological change as is usually postulated. The models are tested using retail sales data for the United States. Good predictions are generally found, especially when the unique CBD of New York City is removed from the data set. However, the model which has the greatest theoretical validity relative to central place theory does not have the best fit to the data. Implications of this are discussed, along with those of utilizing transformations in regression models.
A Discrete‐time Dynamic Analysis of Interregional Population Systems
Authors: Liaw Kao‐Lee
Published: September 2010

This paper uses a system of simultaneous linear difference equations to explain how various dynamic properties of a closed interregional population system are determined by (1) the system's fixed natural growth and migration structure and (2) the initial population distribution. A matrix containing natural growth rates and interregional migration rates is defined as a structural matrix. Based upon structural matrices, interregional population systems are classified into (1) ZPG, (2) Malthusian, (3) mixed, and (4) vanishing systems. The analysis is accomplished by using the Z‐transform method, which can be translated into an efficient computer algorithm. For any closed interregional population system with a fixed structural matrix, it is found that the existence and stability of an equilibrium distribution, the long‐run proportional distribution, the long‐run growth rate, and the location of the “dominant region” are all independent of the initial population size and distribution but are completely determined by the largest eigenvalue and the associated eigenvector of the system's structural matrix. However, the actual population sizes at equilibrium, the saturation and doubling times, and the fluctuations of the system's time paths depend both on the structural matrix and on the initial population size and/or distribution. Analogous to the mean and standard deviation in descriptive statistics, the eigenvalues and eigenvectors extracted from the structural matrix are useful summarizing indices in linear dynamic systems.
Constructing Abstract Worlds of the Past
Authors: Norton William
Published: September 2010

A principal research need in historical geography is the creation of abstract worlds of the past. This study of agricultural settlement patterns in Upper Canada, 1782–1851, assesses the relative rank and sensitivity of land availability, point of entry, land quality, and distance to market in relation to a settler's decision to locate. Settlement patterns for years between 1782 and 1851 are simulated and compared to real world data by means of visual analysis of settlement maps and correlation analysis. For patterns before 1851 the dates of survey are important; by 1851 the effects of this factor are not evident.
The Effects of Data Aggregation in Statistical Analysis
Authors: Clark W. A. V. , Avery Karen L.
Published: September 2010

The problem of ecological correlation is now widely recognized but detailed analyses of the effects of aggregation on correlation and regression coefficients are rare. A short review of the aggregation problem is followed by an analysis of the specific effect of proximity aggregation on the slope coefficient of a bivariate linear model using data drawn from the Los Angeles Metropolitan region. The evidence suggests that changes in the slope coefficient are best related to the manner in which the covariation between the independent and dependent variables changes with increased aggregation.
The Role of Bose‐Einstein Statistics in Point Pattern Analysis
Authors: Thomas R. W. , Reeve D. E.
Published: September 2010

Bose‐Einstein statistics are introduced as the least‐biased definition of equal likelihood or randomness available to geographers studying point patterns. The Bose‐Einstein distribution is shown to be an entropy‐maximizing probability distribution which enables the information theoretic concept of redundancy to be used as a measure of the extent to which an unknown spatial process influences the evolution of the frequency distribution of points. Finally the method is applied to the frequency distribution of karst depressions in limestone regions and the distributions of factories in Greater Manchester.
Extremal Approaches to Estimating Spatial Interaction
Authors: Phillips Fred , White Gerald M. , Haynes Kingsley E.
Published: September 2010

Two recent theoretical approaches to the gravity model of spatial interaction are examined with emphasis on the dissimilar physical and statistical theories from which they were respectively derived. Formal relationships between the two methods are demonstrated. The two approaches jointly indicate a general method of generating new hypotheses of gravity flows. This method is discussed and evaluated, and some questions of theory comparability are explored. Comments on some of the computational features of each of the two models conclude the paper.
Graph Theory Interpretation of Flow Matrices: A Note on Maximization Procedures for Identifying Significant Links
Authors: Holmes J. H. , Haggett P.
Published: September 2010

A maximization procedure for identifying significant links in a flow matrix is described and its use illustrated. The method appears to have advantages over primary‐flow linkage methods and over methods based on flow‐combination procedures.
Some Extensions of Mills's Method for Urban Population Density Gradient Estimation
Authors: Meier P. M. , McCoy T. H.
Published: September 2010

This paper extends Milk's method for estimating urban population density gradients to general noncircular and asymmetrical urban forms, using Gauss‐Legendre quadrature embedded in a Newton‐Raphson root finding algorithm. We also examine the sensitivity of the Mills method to measurement errors in the assumptions. Several issues arising from the comparison of analytical, Mills type estimation procedures with statistical procedures are explored, particularly in light of recent work that questions the negative exponential formulation of urban density gradients. We note in particular the influence of secondary population centers as a source of estimation bias.
Determinants of Rent from Agricultural Land Around Metropolitan Areas
Authors: Kellerman Aharon
Published: September 2010

Three urban determinants of rent from agricultural land around metropolitan areas are incorporated into one rent model. The urban market factor and the transport cost as expressed in the Thünian crop rent equation are discussed in terms of their relevance to metropolitan areas. Then the effects on rent of the urban land market and urban economic change and their relationships with the market factor are examined. Graphic and mathematical expressions of a multideterminant model based on the combined crop system are developed, followed by a discussion on several variations of the model.
On Modeling the Evolution of Hunter‐Gatherer Decision‐Making Systems
Authors: Reynolds Robert G.
Published: September 2010

Models of both primate and hunter‐gatherer decision‐making systems are developed and their relative abilities potentially to detect certain classes of spatial distributions within a standardized environment are compared. It is demonstrated that in situations where language facilitates the pooling of information between individuals within a hunter‐gatherer group, the group minimally need only to pool information with one central decision maker in order potentially to recognize all possible spatial distributions within a limited environment. On this basis alone, we would theoretically expect the presence of one‐leader groups to be a fairly ubiquitous phenomenon among hunter‐gatherers.
The Theory of Welfare Considerations in Public Facility Location Problems
Authors: Bigman David , ReVelle Charles
Published: September 2010

The paper provides a general theoretical framework for analyzing the locational choice of public facilities from the point of view of social welfare. Spatial interactions of individuals and economies to scale in the public sector are taken into account, and that, in turn, adds another dimension to the set of alternatives facing the decision maker. His choice has to be made by considering size as well as space alternatives for the provision of the public service. The paper presents a theoretical structure for ranking those alternatives.
A Procedure for Quantifying Certain Geomorphological Features
Authors: Bosch William
Published: September 2010

In this paper procedures for quantifying geological or geomorphological features are examined. A general approach is suggested and is followed to derive specific quantifications of circularity and sphericity
A Decision‐Making and Search Model For Intraurban Migration
Authors: Smith Terence R. , Clark W. A. V. , Huff James O. , Shapiro Perry
Published: September 2010

Most of the research on the intraurban migration attempting to develop models of the mobility process has presented intuitively appealing statements about the residential decision process, but stopped short of a formal development of these concepts. If it is to be possible to predict the mobility pattern within the city, both the search and selection process must be more clearly specified. In this paper, a preliminary theoretical model containing decision rules similar to those found in optimal search models is developed. The model explicitly incorporates the spatial and temporal aspects of residential choice and has the potential to predict the probability that a prospective migrant will search for a new residence in a given area of the city, the time when the search process will come to a conclusion and, by implication, the expected location of the new residence. The preliminary results from the model suggest a major elaboration of the spatial and temporal aspects of residential choice under conditions of uncertainty in terms of a set of empirically measurable determinants, relating to a household's preferences, beliefs, and degree of risk aversion.
Statistical Tests and Process Generators For Random Field Models
Authors: Haining R. P.
Published: September 2010

Two alternative specifications for random fields are reviewed and models from both specifications identified. The paper then deals with statistical tests for discriminating between randomness and some of the models of dependence. These various tests are compared and criteria established for their use. Additional testing procedures are identified for the more difficult problem of distinguishing between models of dependence. The paper then looks at different process generators for certain random field models and concludes with a discussion of the importance of the theory for handling diffusion processes. The value of these results for both model specification and “form‐process” studies is emphasized.
A Dynamic Model of Growth in a Central Place System
Authors: Allen P. M. , Sanglier M.
Published: September 2010

A model is developed in which the change in the population distribution of a region is linked to the employment pattern, and this latter in turn to the population distribution through the concepts of central place theory. The result is a dynamic model of interacting urban centers in which the fluctuations (the exact history) of the system play a vital role, and with which the effect of an infrastructure decision can be estimated in the long term.
Spatial Models of Spread‐Backwash Processes
Authors: Gaile Gary L.
Published: September 2010

Spread‐backwash processes are central elements in regional development thought. This article argues that the main spread‐backwash processes produce developmental change that has a general spatial form. Straightforward models of the processes of government incomes and expenditure flows, private capital flows, intraregional trade, migration‐commuting, and the diffusion of innovations provide the rationale for the general distance decay form of developmental impact. Each model is supported by evidence from the relevant literature. It is argued that there is not a dichotomous set of spread versus backwash processes, but rather that the same set of processes yields differential spatial impacts.
Stability in a Spatial Production and Trade System
Authors: Laulajainen Risto
Published: September 2010

Basic properties of the production and trade system for sulfur in the North Atlantic sphere are studied. Oligopolistic competition produces a more stable system than polypoly. Occasional exceptions, difficult to anticipate theoretically, are possible, however. When subjected to realistic exogenous shocks in consumption (demand), the system is less stable than if the shocks appear in supply.
Some Second Thoughts about Theory in the Social Sciences
Authors: Couclelis Helen
Published: September 2010

When Professor Papageorgiou submitted his brief essay in the spring of 1982 (“Some Thoughts about Theory in the Social Sciences, GA [October 1982], pp. 340‐46), I decided to use it as a vehicle to provoke a discussion of the issues he raised. I invited a number of scholars to submit brief and informal statements on these issues and these responses are assembled in the following pages. The variety of styles and contents of the submissions reflects the diversity that is contemporary human geography. I hope that this forum enhances our appreciation of the points‐of‐view of others. Convergence towards a single widely accepted epistemological framework appears to be further away than ever.
Multipurpose Shopping and the Location of Retail Firms
Authors: McLafferty Sara L. , Ghosh Avijit
Published: September 2010

This paper investigates the effects of multipurpose shopping on spatial competition among retail firms. Multipurpose shopping leads to a dispersion of competing firms even in Hotelling‐type scenarios. The degree of dispersion depends on individual propensities for multipurpose shopping which are determined by the relative costs, demands, and prices for various goods.
A Spatial Typology of Israel on the Basis of Partial‐Order Analysis
Authors: Lipshitz Gabriel
Published: September 2010

In the present study, a relatively new analytical technique—“Partial Order Scalogram Analysis with Base Coordinates” (POSAC)—is used to integrate subjective and objective measurements in the same way that other clustering techniques can be used to reduce a large number of observations to a limited number of major groups. The technique is applied to a geographical problem, involving 34 regions in the State of Israel, the economic welfare of which is characterized by means of ten objective socioeconomic variables and five subjective variables. The 34 regions are reduced to 5 manageable geographical spheres.
Income Diffusion and Spatial Econometric Models
Authors: Haining Robert
Published: September 2010

This paper considers the development of linked small‐area spatial econometric models in which income flows between the areas constitute an important part of model specification. The attributes of income diffusion processes are considered in detail. Both static models and temporal income diffusion models are discussed. The spatial and spatial‐temporal autocorrelation functions are derived which provide a measure of the spatial distribution of income. The Green function is also derived as a measure of income impulses through the system of regions. An important aspect of the paper is to relate properties of these functions to key economic parameters in particular propensities to spend locally and to spend nonlocally.
Disaggregate Migration Behavior and the Volume of Interregional Migration
Authors: Odland John , Ellis Mark
Published: September 2010

Nested multinomial logit models are used to investigate migration behavior during the 1971–74 period for a large sample of the population of Ecuador. The nested form of the model makes it possible to test hypotheses about the importance of destination characteristics in conditioning the odds for out‐migration. Our empirical results indicate that the odds for migration from each origin are conditioned by the expected utilities of the available set of destinations, as well as characteristics of the origins and the personal characteristics of potential migrants. The association between destination characteristics and the frequency of out‐migration allows the total volumes of migration to be adjusted to interregional differences in place‐specific utilities.
On the Imprecision of Boundaries
Authors: Leung Yee
Published: September 2010

Imprecision of regional boundaries is subjected to a formal analysis within a fuzzy set theoretic framework. Regions are characterized by linguistic propositions which have precise mathematical translations. It is demonstrated that boundaries are generally fuzzy and exist as gradients rather than lines. Similarly, regions overlap to a certain extent. Though regional characterizations are imprecise, the extent of a fuzzy boundary can be exactly demarcated. Concepts of regional cores and edges are also examined. A simple climatic classification problem is employed to illustrate the theoretical arguments. The framework appears to be more natural, informative, and flexible. It comprises the conventional regional concepts as special cases.
An Approach to Urban Dynamics
Authors: Orishimo Isao
Published: September 2010

Spatial cycles that are general to the urbanization process have been widely observed in the developed countries. These include (a) the decline of large agglomerations and the emergence of medium‐sized municipalities, and (b) population decreases in the core and population increases in the suburban parts of the metropolitan area, followed later by contrasting increases in the core and decreases in the suburbs. In this paper, we formulate a mathematical model for such spatial cycles of the urbanization process as those mentioned above. Based on this model, we ascertain some general characteristics of these cycles of urban dynamics. From our findings, we can propose a long‐term strategy for the urbanization process.
Metropolitan Housing Subsystems: A Comparative Review
Authors: Leushacke Clemens , Wegener Michael
Published: September 2010

Population, household, and housing data of twelve cities in industrialized countries are compared with respect to different rates of growth or decline in the inner and outer parts of the urban area. The study shows that in nearly all metropolitan areas the core declines in terms of population, but less in terms of households, and is stable or grows in terms of dwellings. This phenomenon can be characterized as a process of “spatial substitution” from core to periphery which is fast in terms of population, but slow in terms of dwellings because of the inherent inertia of the physical stock of the city. Following Batten (1985), a logistic substitution model is used to compare the speed and duration of spatial substitution in the urban areas studied. It is found that the process is similar in most urban areas, but that the cities have reached different points along its course. The conclusion is that the residential deconcentration observed in most urban areas in industrial countries is mainly a consequence of overall population growth or decline, decreasing household size, increasing per capita consumption of floor space, and lack of land in the core.
The Geometric Properties of Numerical Generalization
Authors: McMaster Robert B.
Published: September 2010

Over the past twenty years, cartographers have become increasingly concerned with the nature and quality of cartographic data in digital format. One significant area of research has been in the generalization of these digital data. Specifically, algorithms have been developed to (1) weed out unnecessary detail, (2) smooth sharp angularity, (3) displace two features coalescing due to scale change, and (4) enhance certain characteristics of the data. This paper presents an analysis of nine algorithms developed for simplifying the superfluous detail in digital cartographic lines. A series of geometric measures were designed to evaluate the changes produced by simplification. These included both single attribute measures, which evaluate changes such as line length and angularity, and displacement measures, which evaluate geometric displacement such as area. The results of this analysis, using four digitized naturally occurring lines and their simplifications, indicates that four algorithms: DOUGLAS, OPHEIM, REUMANN, and LANG are mathematically superior. Although the Douglas routine was slightly better—in terms of area displacement—than the other three, it is the most computationally complex algorithm. Thus for certain mapping tasks, such as in thematic cartography, other routines such as LANG tolerancing appear more appropriate.
Population Oscillations in a Nonlinear Migration Model
Authors: Zhang Wei‐Bin
Published: September 2010

The purpose of this paper is to prove the existence of Hopf bifurcations in Sheppard's generalized dynamic migration model. Hopf bifurcations appear as a result of structure changes in the system. First, we deal with the general case of H cities. Then, the case of two cities is dealt with.
Migration and Occupational Choice among Young Labor Force Entrants: A Human Capital Model
Authors: Odland John
Published: September 2010

Interregional variations in the conditions for entering the labor force are investigated by analyzing interdependencies between migration behavior and occupational choice for young labor force entrants. The human capital framework indicates that occupational choice depends on the costs and returns associated with entering various occupations, and that interregional variation in these costs and returns is a major reason for migration. Occupational choice and migration behavior will be interdependent if the costs and returns for particular occupations vary over local labor markets, relative to other occupations, and patterns of interdependence between the two decisions are analyzed, using a model of the joint choice of occupation and location. An empirical analysis of occupational choices and migration behavior for young people who entered the U.S. labor force in the 1975–80 period indicates that the odds for entering professional or managerial occupations varied with origin and migration behavior in systematic ways.
The Role of Spatial Scale in Geomorphic Systems
Authors: Phillips Jonathan D.
Published: September 2010

Geomorphic systems are characterized by numerous, complex interrelationships between system components, and by processes and controls which may operate over different spatial scales. Factors operating at any given spatial scale can be viewed as an abstracted subset of all relationships operating at all scales. The theory that relationships which operate over spatial scales an order of magnitude different are effectively independent of each other is formally stated in terms of abstracted systems. An example is given to illustrate the use of spatial statistics to determine what constitutes a significant spatial scale difference in controls over hydraulic geometry of a desert wash.
The Fractal Theory of Central Place Geometry: A Diophantine Analysis of Fractal Generators for Arbitrary Löschian Numbers
Authors: Arlinghaus Sandra L. , Arlinghaus William C.
Published: September 2010

We develop material to determine whether or not an arbitrary number is Löschian; the procedure embodied in the theorems achieves the desired result more swiftly than do previous solutions to this problem. The correspondence between a partition of the central place lattice and a quadratic form permits the rapid determination of the lattice coordinates of an arbitrary Löschian number and of the exact shape of a single fractal generator used to form an entire central place hierarchy associated with an arbitrary Löschian number. Central place hierarchies may be generated geometrically using a single shape applied initially to a hexagon and subsequently, scaled appropriately, to resultant polygons. Fractional dimensions of arbitrary central place hierarchies, measuring their “space‐filling” characteristics, follow naturally from this general procedure.
Minimum‐Cost Distances in Spatial Analysis
Authors: Huriot J.M. , Smith T. E. , Thisse J‐F.
Published: September 2010

An axiomatic approach to distance is developed which focuses on those behavioral concepts of distance related to movement in space. In particular, spatial movement by behaving units is postulated to involve a choice from among some set of abstract trips in space, and implicitly, to involve the minimization of some relevant notion of trip costs. In this context, the relevant behavioral notion of distance in space is taken to be the minimum‐cost distance generated by this choice process. These trip‐cost concepts extend the classical notions of paths, path lengths, and shortest paths in metric spaces. Hence many of the analytical results of the paper involve extensions of classical shortest‐path distance properties to minimum‐cost distances. In addition to these extensions, a characterization theorem is given which specifies the possible functional relationships between trip costs and their associated path lengths. These relationships include most functional forms which are commonly employed in the literature.
A Spatial Search‐Location Model of Retail Centers
Authors: Kohsaka Hiroyuki
Published: September 2010

Central place theory can be modeled using two types of optimization problems. Location‐allocation models have been widely applied to operationalize central place theory as an aggregate optimization problem. This paper constructs a spatial search‐location model to formulate central place theory as an individual optimization problem.
Consumer and Producer Behavior in a Multipurpose Shopping Environment
Authors: Ingene Charles A. , Ghosh Avijit
Published: September 2010

This paper analyzes the shopping behavior of consumers across space within the context of multipurpose shopping. The degree of multipurpose shopping is derived, as are the optimal number of single‐ and multipurpose trips, and the quantities of high‐ and low‐order goods purchased on such trips. It is shown that all consumer choice variables are a function of consumer location relative to producer location. The consumer analysis is then utilized as an input into the profit‐maximizing equation that determines optimal producer location. The model is illustrated through the use of numerical analysis.
Regional Out‐Migration Rates and Migration Histories: A Longitudinal Analysis
Authors: Odland John , Bailey Adrian J.
Published: September 2010

A longitudinal approach to migration behavior makes it possible to identify a sufficient condition for positive associations between rates of in‐migration and rates of out‐migration in the same regions. The longitudinal approach centers on the intervals of time that individuals spend in a region, and these intervals can be analyzed in terms of probability distributions or the equivalent hazard functions or survivor functions. Differences in the distributions of these intervals between subpopulations whose residence in a region begins with in‐migration and subpopulations whose residence begins with other events are sufficient for temporal variations in rates of in‐migration to produce variations in out‐migration rates in subsequent periods of time. Tests for such differences are performed using data from the National Longitudinal Survey of Youth.
Residents' Spatial Knowledge of Neighborhood Continuity and Form
Authors: Aitken Stuart C. , Prosser Rudy
Published: September 2010

This paper discusses residents' cognition of neighborhood form in terms of linear‐based and areal‐based knowledge structures. Cognitive and behavioral data are used to create surfaces of residents' familiarity with, and experience of, a neighborhood in San Diego, California. The complexity of the data required the topological and relational sophistication of an ARC / INFO‐based geographic information system. Cellular‐based data were collected to identify place‐specific measures of residents' familiarity and experience within the community. The cellular data facilitated aggregation of residents' cognitive surfaces as absolute spaces, and also relative to their homes. Spatial autocorrelation and directional autoregression techniques are used in association with standard cognitive mapping to establish the continuity and form of residents' familiarity and experience with their neighborhood. The findings suggest that there is a structural difference in the spatial familiarity of residents who perceive their neighborhood as an area and those who perceive it as a network. North‐south and east‐west street networks played an important part as the basis for both linear‐based and areal‐based knowledge, but noncardinal directions were more prominent in the familiarity surfaces of those residents who had an areal‐based perception of neighborhood form. In terms of theories of spatial knowledge acquisition, the findings suggest that (i) there may not be a direct sequential link between linear‐based and areal‐based knowledge structures, (ii) knowledge of a complex network may not be sufficient to provide areal‐based knowledge, and (iii) an areal‐based knowledge structure does not necessarily comprise an understanding of survey procedures.
Map Resolution and Spatial Autocorrelation
Authors: Chou Yue Hong
Published: September 2010

Moran's I, a measure of spatial autocorrelation, is affected by map resolution and map scale. This study uses a geographic information system (GIS) to examine the resolution effects. Empirical distribution of wildland fires in Idyllwild, California, and hypothetical distributions of ordered patterns are analyzed. The results indicate that Moran's I increases systematically with the resolution level. The resolution effects can be summarized by a log‐linear function relating the I coefficients to resolution levels. Empirical tests that compare the distribution of fire activity in a vegetation map and in a topographic map confirm the resolution effects observed.
Modeling Migration Careers, Using Data from a British Survey
Authors: Davies Richard B. , Flowerdew Robin
Published: September 2010

Development of more sophisticated techniques for modeling longitudinal data has implications for improving our understanding of migration. This paper uses longitudinal data from the British Social Change and Economic Life initiative to disentangle the effects of population heterogeneity, progress through the life cycle and secular change on observed migration differentials. The data consist of retrospective life histories from people sampled in several contrasting localities in Great Britain, in which residential moves can be linked to changes in occupation and household structure. We present a framework for analysis of data of this type using a generalized linear modeling approach, together with results concerning variations in the probability of migration with age, gender, and changes in household and occupational circumstances. Of particular note is the evidence of substantial duration‐of‐residence effects and an unexpected later‐career increase in migration propensity.
Smoothing Regional Maps Using Empirical Bayes Predictors
Authors: Cressie Noel
Published: September 2010

Maps are one of the geographer's basic tools. Suppose the data to be mapped are values of a variable (for example, sudden infant deaths per thousand live births, percentage undercount in a census, etc.) that are known only by region (for example, counties, enumeration districts). From the point of view of pure data summary, a map of the regions coded or colored according to the values of the variable is a very effective way of presenting both the data and the regional geography. However, it is tempting to use such a map for other purposes, such as cluster detection and comparison with previous time periods. This article will concentrate on the important case where the variable mapped is a rate. Since such rates have a nonconstant base, one is faced with a statistical comparison of regional data whose variances may be highly different. Thus, if the regional map is to be used to look for spatial patterns in the data, it is important to map smoothed values that take into account the spatial inhomogeneity of variances, as well as any spatial dependence between regions.
Evaluating Tobler's Migration Vector Fields
Authors: Clark W. A. V. , Koloutsou‐Vakakis Sotiria
Published: September 2010

In the past decade Tobler has provided an innovative cartographic presentation of migration flows. The central theme of this research has been to utilize detailed migration data to reveal the underlying structures of migration flows. Even though the analyses are not explanatory models of migration exchanges, the application of these techniques to migration flows over time and across different spatial scales provides a visual generalization of often extremely complex flows. The application of his techniques at two spatial scales for the Netherlands illustrates both the strengths and weaknesses of migration force fields for the analysis of migration.
Interstate Differences in Relative Export Performance: A Test of Factor Endowments Theory
Authors: Erickson Rodney A. , Hayward David J.
Published: September 2010

In a state‐level analysis, relative export efficiencies are regressed on the capital (labor) intensity of production across industries. Resulting parameters are regressed on human and physical capital endowments. Factor endowments are significant, but account for limited variation; global product demand, scale economies, and industrial inertia may also be important determinants.
A Time Series Analysis of Regional Income Inequalities and Migration in Japan, 1955–1985
Authors: Gauthier Howard L. , Tanaka Kyoko , Smith W. Randy
Published: September 2010

This study tests the neoclassical concept of interregional migration in post–World War II Japan. The lead‐lag relationship between net migration to a core area and regional income inequalities is examined by modeling an ARIMA transfer function. Until 1961, there was a rapid growth in net migration from the periphery to the core area that was accompanied by rapid divergence in regional income inequalities. Since then, migration to the core apparently has declined due to a convergence of regional income inequalities. The time series analysis indicates there has been short‐run, as well as long‐run, volatility in migration related to cyclical variations in economic performance in the core.
Site Selection Problem and a Quasi‐Satisficing Decision Rule
Authors: Malczewski Jacek
Published: September 2010

This discussion and overview of the site selection problem in the context of a quasi‐satisficing decision rule combines two major rationality frameworks for locational decision making: utility maximization and bounded rationality. Their empirical and logical validity is discussed. From these concepts a quasi‐satisficing rationality framework is developed and operationalized through a reference point approach. A quasi‐satisficing decision‐support procedure that involves a feed‐back exchange of information between a decision maker and a computer‐based support system is offered and a numerical illustration of this procedure is presented.
Exogenous Workplace Choice in Residential Location Models: Is the Assumption Valid?
Authors: Waddell Paul
Published: September 2010

This paper examines the assumption implicit in most models of residential location that the choice of workplace is exogenously determined. Monocentric models have generally made this assumption, but it has come under increasing scrutiny. A nested logit model of workers' choices of workplace, residence, and housing tenure within the Dallas‐Fort Worth metropolitan area is developed to provide a test. A unique dataset that includes the workplace and residence census tracts of workers in Dallas‐Fort Worth, and their demographic and socioeconomic characteristics, is used to estimate the model. The results confirm that a joint choice specification better represents actual choice behavior in a multinodal metropolis.
The Formation of a Composite Urban Image
Authors: Stern Eliahu , Krakover Shaul
Published: September 2010

Since image formation depends on the cognitive organization of perceptions, a change in the individual's available cognitive structure may affect his or her perceptual selectivity. This, in turn, might lead to a reconstruction of the image through selected fields of attention. Although this process is widely accepted, little is known of its neurophysiology, and the formation of an image, therefore, is drawn inferentially from introspective reports. This paper presents, accordingly, a conception of image formation and tests it with a model presenting paths among locational and nonlocational environmental stimuli and an introspective measure of a composite urban image. Changes in the paths due to information and personal attributes that reflect different realms (for example, fields of attention) are further examined with an expanded version of the model. Across the realms, the perceived residential appeal and the perceived level of activities are the main determinants of the composite urban image. Information and personal attributes not only affect the mix of image determinants, but also rearrange their relative effects on the emerging image.
Search and Fetter's Law of Markets
Authors: Gillen William J. , Guccione Antonio
Published: September 2010

Fetter's law, a classical result of location theory, is respecified to include search costs. Then the implied partition of the market space is derived.
Categorical Wombling: Detecting Regions of Significant Change in Spatially Located Categorical Variables
Authors: Oden Neal L. , Sokal Robert R. , Fortin Marie‐Josée , Goebl Hans
Published: September 2010

Wombling is a method for discovering boundaries in a collection of continuous variables observed at the same geographic localities. We extend this method to categorical data. A categorical wombling statistic Ci, which identifies areas of rapid change, is defined for every pair i = 1,…, n of adjacent localities, and is equal to the average number of category mismatches at i. We use both simulation and theory to consider the order statistics of Ciunder null hypotheses of randomness, and of spatial autocorrelation for each variable, but independence between variables. Graph‐theoretical statistics derived from Ciinvestigate whether areas of rapid change resemble boundaries. Computer simulation is used to study the distributions of these under the two null hypotheses. The methods are applied to linguistic data in three European areas. Other potential applications exist in biology, linguistics, anthropology, and other social sciences.
The Zone Definition Problem in Location‐Allocation Modeling
Authors: Fotheringham A. Stewart , Densham Paul J. , Curtis Andrew
Published: September 2010

Location‐allocation modeling is a frequently used set of techniques for solving a variety of locational problems, some of which can be politically sensitive. The typical application of a location‐allocation model involves locating facilities by selecting a set of sites from a larger set of candidate sites, with the selection procedure being a function of “optimality” in terms of the allocation of demand to the selected sites. In this paper we examine the sensitivity of one particular type of location‐allocation model, the p‐median procedure, to the definition of spatial units for which demand is measured. We show that a p‐median solution is optimal only for a particular definition of spatial units and that variations in the definition of spatial units can cause large deviations in optimal facility locations. The broad implication of these findings is that the outcome of any location‐allocation procedure using aggregate data should not be relied upon for planning purposes. This has important implications for a large variety of applications.
Foreign Aid and Economic Growth: An Empirical Analysis
Authors: Bowen Janine
Published: September 2010

After more than forty years of foreign aid programs and numerous studies of the impact aid has had on economic growth in recipient countries, the strength and nature of the aid‐growth relationship is still unknown. This study contends that results from previous studies have in aggregate been inconclusive largely because of methodological limitations and that a significant aid‐growth relationship does exist. Further, the nature of the relationship (for example, positive or negative) varies across the level of economic development in aid‐receiving countries. The expansion method is used here to expand initial models of economic growth into models which better explain the aid‐growth relationship by incorporating the relationships that aid may have with other determinants of economic growth.
A Cost‐Benefit Location‐Allocation Model for Public Facilities: An Econometric Approach
Authors: Fortney John
Published: September 2010

This research develops and operationalizes a facility location‐allocation model based on cost‐benefit principles derived from welfare economics. Despite the theoretical advantages of cost‐benefit location‐allocation models, the difficulties associated with estimating household preferences for public facilities have heretofore prevented their application. This research demonstrates that the hedonic‐pricing methodology can be effectively used to estimate preferences for public facilities. Specifically, household preferences for Baltimore public middle schools were estimated from the spatial variation in housing prices using the random bidding model. To provide an example of the methodology, the cost‐benefit location‐allocation objective function was maximized to simultaneously determine the optimal number, quality, and locations of Baltimore middle schools. The cost‐benefit approach to facility location constitutes a major improvement over existing methods because it directly incorporates user preferences into the objective function and because the number and quality of facilities can be determined endogenously rather than being specified as a constraint a priori.
Alternative Population Dynamics in Selected HIV/AIDS Modeling Systems: Some Cross‐National Comparisons
Authors: Thomas Richard
Published: September 2010

This paper examines how demographic representations for the different risk populations influence the epidemic outputs of a simple process‐based HIV/AIDS model. Alternative demographic specifications are presented in conjunction with transmission rules for both community and regional settings. Then, the existence, or nonexistence, of equilibrium solutions to these various models is determined to evaluate whether the forecast AIDS series will persist indefinitely or eventually terminate. Last, simulations for countries with distinctive birth and death rates are used to summarize the effect of this variation on the timing and size of the epidemic. All the results assume an epidemic that is unaffected by the practice of safer sex.
An Efficient Search Strategy for Site‐Selection Decisions in an Expert System
Authors: Arentze Theo A. , Borgers Aloys W. J. , Timmermans Harry J. P.
Published: September 2010

This paper describes an algorithm for spatial search, which is used in an expert system for site selection. The algorithm, named ProfMat, is able to find the best site in the area of interest even when the number of possible sites is large and many decision criteria are involved. Compared to commonly used search procedures, ProfMat improves the efficiency of spatial search in two ways. First, the best site is identified through an iterative rather than a linear process of selection and evaluation of optional sites. Second, an area is searched by narrowing down the focus to increasingly smaller areas and, thus, sites are evaluated as much as possible groupwise. The ProfMat procedure is illustrated by analyzing the problem of retail site selection. A comparison with alternative search procedures shows that ProfMat considerably reduces the evaluation costs needed to find the best site. The implementation of the algorithm in an expert system shows how ProfMat can be used in combination with specialist's knowledge to solve site‐selection problems. The efficiency of the procedure allows considering large sets of optional sites, so that it may improve the quality of the outcome.