bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence of meniscus interface transport in dip-pen nanolithography: An annular diffusion model
Authors: Nafday Omkar A. , Vaughn Mark W. , Weeks Brandon L.
Published: October 2006

Ring shaped dots were patterned with mercaptohexadecanoic acid ink by dip-pen nanolithography. These dots have an ink-free inner core surrounded by an inked annular region, making them different from the filled dots usually obtained. This suggests a different transport mechanism than the current hypothesis of bulk water meniscus transport. A meniscus interface ink transport model is proposed, and its general applicability is demonstrated by predicting the patterned dot radii of chemically diverse inks.
Computation of dipole, quadrupole, and octupole surfaces from the variational two-electron reduced density matrix method
Authors: Gidofalvi Gergely , Mazziotti David A.
Published: October 2006

Recent advances in the direct determination of the two-electron reduced density matrix (2-RDM) by imposing known N-representability conditions have mostly focused on the accuracy of molecular potential energy surfaces where multireference effects are significant. While the norm of the 2-RDM’s deviation from full configuration interaction has been computed, few properties have been carefully investigated as a function of molecular geometry. Here the dipole, quadrupole, and octupole moments are computed for a range of molecular geometries. The addition of Erdahl’s T2 condition [Int. J. Quantum Chem. 13, 697 (1978)] to the D, Q, and G conditions produces dipole and multipole moments that agree with full configuration interaction in a double-zeta basis set at all internuclear distances.
Comment on “Graphical analysis of electron inertia induced acoustic instability” [Phys. Plasmas 12, 032105 (2005)]
Authors: Hirose A.
Published: October 2006

The ion flow driven acoustic instability reported in Phys. Plasmas 12, 032105 (2005) is a result of improper expansion of the dispersion relation and violates the basic electron adiabaticity condition ∣ω∣≪kvTe (electron transit frequency) upon which the analysis is based. An unabridged (unexpanded) dispersion relation does not predict any instability when the ion flow is of the order of the ion acoustic speed.
Parametric study of atmospheric pressure microwave-induced Ar∕O2 plasmas and the ambient air effect on the plasma
Authors: Moon Se Youn , Choe W.
Published: October 2006

A torch type microwave-induced afterglow plasma was produced at atmospheric pressure using an open-ended fused silica concentric double tube assisted by Ar and O2 supply gases. The plasma emerged from the end of the discharge tube and was exposed to ambient air. A parametric study of the plasma characteristics was performed by measuring the temperature, density, and plasma volume as the operational parameters such as microwave power, gas flow rate, and its composition were varied. The excitation temperature (Texc) obtained from the Ar I emission spectrum ranged from 3010to4350K and the rotational temperature (Trot) measured from the OH and O2 diatomic molecular spectra ranged from 2250to3550K. The electron density (ne) from the Hβ Stark broadening width at the plasma core was in the range of 6.6to7.6×1014cm−3. The two-dimensional distribution of Texc and Trot was also obtained. Experiments while varying the Ar and O2 gas flow rate and the O2∕Ar ratio showed that ne was reduced but Texc was increased as the O2 flow rate was increased. Using an additional dielectric tube for shielding the plasma from the ambient air demonstrated a significantly enlarged plasma length and lower Trot due to the nitrogen entrainment, as compared to the unshielded case.
Kinetic theory for radiation interacting with sound waves in ultrarelativistic pair plasmas
Authors: Marklund Mattias , Shukla Padma K. , Stenflo Lennart
Published: October 2006

A kinetic theory for radiation interacting with sound waves in an ultrarelativistic electron-positron plasma is developed. It is shown that the effect of a spatial spectral broadening of the electromagnetic pulse is to introduce a reduction of the growth rates for the decay and modulational instabilities. Such spectral broadening could be due to a finite pulse coherence length, or through the use of random phase filters, and would stabilize the propagation of electromagnetic pulses.
Self-consistent simulation of quantum transport and magnetization dynamics in spin-torque based devices
Authors: Salahuddin Sayeef , Datta Supriyo
Published: October 2006

This letter presents a self-consistent solution of quantum transport, using the nonequilibrium Green’s function method, and magnetization dynamics, using the Landau-Lifshitz-Gilbert formulation. This model is applied to study “spin-torque” induced magnetic switching in a device where the transport is ballistic and the free magnetic layer is sandwiched between two antiparallel (AP) ferromagnetic contacts. A hysteretic current-voltage characteristic is predicted at room temperature, with a sharp transition between the bistable states that can be used as a nonvolatile memory. It is further shown that this AP pentalayer device may allow significant reduction in the switching current, thus facilitating integration of nanomagnets with electronic devices.
Effect of doping profile on the lifetime of green phosphorescent organic light-emitting diodes
Authors: Lee Jun Yeob
Published: October 2006

The lifetime of green phosphorescent light-emitting diodes was improved by using a graded doping structure in light-emitting layer. A green device with high doping concentration at the hole transport layer and light-emitting layer interface showed longer lifetime than a conventional device with uniform doping concentration for the whole light-emitting layer by more than 60%.
Enhancement of magnetic properties in (Ga,Mn)N nanowires due to N2 plasma treatment
Authors: Baik Jeong Min , Shon Yoon , Kang Tae Won , Lee Jong-Lam
Published: October 2006

The local structure of Mn impurities in ferromagnetic (Ga,Mn)N nanowires was investigated using extended x-ray absorption fine structure (EXAFS). By N2 plasma treatment, the nitrogen concentration increased and the ferromagnetic signal also increased. The EXAFS results showed that the Mn concentration occupying Ga sites increased and interstitially doped Mn atoms significantly decreased due to the plasma treatment. As a result, the N vacancies reduced and crystalline quality improved, resulting in the enhancement of ferromagnetic properties.
Combinatorial Programming and the Planning of Urban and Regional Systems
Authors: Scott A.J.
Published: October 2006

This paper reviews and evaluates some of the major recent developments in combinatorial programming. General solution procedures are discussed. A variety of planning applications is then examined. These applications are initially categorized as either (a) network or graph-theoretic problems, or (b) grouping and partitioning problems. The role of these various methods and applications in the planning of urban and regional systems is then critically assessed.
Urban Social Theory and Research
Authors: Pahl R.E.
Published: October 2006

This paper commences with a critical examination of the state of urban social theory and research. The author then goes on to propose a focus for future urban social research, this focus being on the distribution of resources and facilities in urban areas. In particular, the managers of the urban system should be picked out for scrutiny.
Multi-Organisational Decision Processes in the Planned Expansion of Towns
Authors: Friend J.K. , Hunter J.M.H.
Published: October 2006

The concept of the ‘multi-organisation’ is used to obtain a clearer view of the problems of decision-making in one field of public planning where the pattern of organisational responsibilities is exceptionally diffuse: that relating to the planned expansion of towns to channel the pressures for change within a region. Four basic types of multi-organisational activity are identified, concerned with the redistribution of population and employment within a region, the negotiation of local agreements, the coordination of local operations, and the coordination of external authorisations by different government agencies. Some of the main characteristics of these four activities are identified, and it is argued that a basis for predicting the effectiveness of alternative organisational patterns can be developed through the analysis of different sources of uncertainty as perceived by those actually involved in the decision process.
The Nature of Rent-Controlling Legislation in the UK
Authors: Nevitt Adela A.
Published: October 2006

The author takes a fresh look at the introduction of rent controls and their justification. She examines the tenants' need for ‘security of tenure’ and considers some of the undesirable social consequences which stem from tenancies ‘at will’. Alternative methods of granting security of tenure are examined to assess their economic consequences, and it is shown that these do not differ very significantly from those which rent controls produce. A general question is posed on the difference between an ‘individual contract’ approach to the legal difficulties of insuring security of tenure over time, as opposed to a statutory contract which covers whole groups in the population. The author makes a plea for bringing together the best of these two legal possibilities and criticises certain aspects of present British rent control machinery.
The Use of Trend-Surface Parameters in Inter-Urban Comparisons
Authors: Haggett P. , Bassett K.A.
Published: October 2006

The general problem of comparing isarithmic maps of different urban areas is examined. Proposed solutions by Merriam and Sneath (1966) and Haggett (1967) are revised in the light of the indicated instability of coefficients under shifts in the grid systems for such maps. A number of stable classifications of city structures can be built up which are invariant under orthogonal grid rotations but most of these break down under non-orthogonal rotations. Variances accounted for by successive terms (linear, quadratic, cubic) appeared stable and are recommended for preliminary analysis. The fundamental problems of pattern analysis remain unresolved by trend-surface coefficients. The argument in the paper is largely empirical and is illustrated from simulated urban patterns and by fifteen sample metropolitan areas from the United States.
On the Efficiency of Alternative Aggregations in Region-Building Problems
Authors: Cliff A. D. , Haggett P.
Published: October 2006

It is clear that, whenever sub-areas are aggregated into regions, the set of regions obtained is only one of a large number of alternative groupings. To illustrate this, equations are derived which give the number of different ways n counties may be grouped to form k regions, k ≤ n, in two limiting situations: the totally unconstrained case, in which each county may be grouped with any other county; and the maximally constrained case, when each county can only be grouped with its physically contiguous neighbours. A measure of the efficiency, co, of any regional grouping is given, and the problem of finding the regional grouping with the ‘best’ value of co in the set of alternative grouping patterns is discussed.
The Location Problem of Given and Indivisible Different Units
Authors: Jándy G.
Published: October 2006

In cases where certain simplifications are allowed, the location optimisation of given and indivisible different economic units may be modelled as a bi-value weighted distribution problem. The paper presents a heuristic algorithm for this network-flow-type problem and also a partial enumeration algorithm for deriving the exact solution. But it is also pointed out that an initial sub-optimal solution can quickly be improved with a derivation on a direct line only, if the exact solution is not absolutely essential. A numerical example is used to illustrate the method of derivation on a direct line starting with an upper bound given by a sub-optimal solution.
How Do Contact Systems Affect Regional Development?
Authors: Thorngren B
Published: October 2006

The paper reports on theoretical and empirical studies of contact systems. It refines and extends the framework, and consequently the implications, of such systems. This framework forms a base for extensive empirical studies, the results of which are used to suggest how contact systems are resolved and how they affect the quantitative and qualitative aspects of regional development. The analysis aims to determine how control of the course of development can be exerted by planning bodies at various levels.
Regionalisation of National Planning—Some Methodological Issues
Authors: Hermansen T
Published: October 2006

The paper discusses methodological issues that arise when national planning is attempted which is regionalised and integrated with the traditional forms of physical and community development planning at the regional level. Distinctions are made between control and operational decisions and between analytical target planning and institutional planning. Decisions are furthermore classified according to levels in the decision-making hierarchy, and according to their sectoral and spatial dimensions, resulting in a multi-level, multi-sectoral, and multi-regional system of decision-making and planning activities. The key problem arising is that of distributing decision-making authority among the decision units and superimposing a planning and information exchange system that not only guarantees consistency, but also ensures efficiency in inter-sectoral growth patterns as well as with respect to location of project and utilisation of regional resources and external economies.
Urban Acquaintance Fields: An Evaluation of a Spatial Model
Authors: Moore E G , Brown L A
Published: October 2006

The present paper is concerned with examination of the spatial characteristics of empirical data relating to contact fields for a sample of residents in Cedar Rapids, Iowa. It is shown that a model of individual urban contact fields described in an earlier paper (Moore, 1970) provides interesting insights into the spatial characteristics of the empirical contact fields. The model is briefly presented, its aggregate form is derived, and the data are then examined with reference to the aggregate-level model.

Analysis of person-to-person contacts may be regarded as the first step towards identification of spatial regularities in information flows(1). Most studies of contact fields have been quite restrictive in their spatial representation, having adopted distance-decay functions as the prime means of description (Hägerstrand, 1957; Marble and Nystuen, 1963; Morrill and Pitts, 1967; Marble and Bowlby, 1968). If the distribution of opportunities for contact is neither uniform nor possesses a symmetrical decline in frequency with increasing distance from the respondent, fitting distance-decay functions to observed contacts tends to hide interesting spatial properties of contact fields. This paper is concerned, therefore, with examining the validity and implications of the aggregated form of a model of individual urban contact fields in an empirical situation.
Evaluating Community Preferences
Authors: Hoinville G
Published: October 2006

This paper describes a new method of research developed by Social and Community Planning Research during the past eighteen months. The aim of the research was to arrive at measurements of community preferences so that priority values could be quantified. The method relies on interviews with groups of people who have differing experiences of the variables under study. During the course of the interview, they are asked to play a priority evaluation ‘game’ using an electronic device built for that purpose. This approach extends traditional attitude survey measurements by allowing and ensuring that respondents understand the concept of trade-off preferences.
Competitive Equilibrium of Transportation and Housing in the Residential Ring of an Urban Area
Authors: Hochman O , Pines D
Published: October 2006

A general approach to competitive equilibrium within an urban area is suggested in this paper. The demand for transportation is incorporated into the equilibrium conditions of the household, and in turn the equilibrium conditions of the household are incorporated into the existing models of market equilibrium. The resulting relations are used to verify the characteristics of the prices of housing, rents, velocity, transportation costs, and densities. The implications of the model are consistent with the exponential form of the velocity function observed empirically by Angel and Hyman (1970). These implications illuminate the question of efficient resource allocation in improving the transportation system in the proximity of the CBD. Earlier explanations of the exponential density function given by Muth (1969) are verified and shown to be insufficient.
Some Factors Affecting the Use of New Techniques in Planning Agencies
Authors: Wade B F
Published: October 2006

This paper presents a set of hypotheses concerning some of the important factors affecting the successful introduction of new planning techniques into a planning agency. Factors connected with the characteristics of the planning technique are examined first, followed by an examination of those factors related to the characteristics of the planning agency.
Towards a Three-Dimensional Model of Planning Behaviour
Authors: Faludi A
Published: October 2006

This paper develops conceptual tools for the analysis of planning behaviour. These are, firstly, a model of planning systems as learning systems, and then three dimensions of planning behaviour, each described by defining a pair of dichotomous concepts at their far ends: ‘blueprint’ versus ‘process’ modes of planning; ‘rational-deductive’ decision-making versus ‘disjointed incrementalism’; ‘normative’ versus ‘functional’ planning. Each of these concepts is discussed in detail, and some indicators for the analysis of planning behaviour are suggested. Finally, a more complex model is constructed which combines the three dimensions. Elements of this model are firstly the level at which planning is conducted within a hierarchy of planning systems, and secondly, the ‘planning sub-structurel, that is the technology-image reflecting the nature of planning problems and available planning technologies. From this model one can derive a number of researchable hypotheses about planning behaviour.
The Formalization and Testing of Concepts of Growth Poles in a Spatial Context
Authors: Casetti E , King L J , Odland J
Published: October 2006

This paper commences with a discussion of the formal characteristics that economic growth in a spatial setting must possess in order to be legitimately regarded as polarized growth. The conditions both for the case of a single growth pole and for the case of several growth poles are considered. A method is then outlined for determining whether or not spatially polarized growth does occur in a particular context, the method being illustrated by use of employment growth data for thirteen cities in the western United States.
The Economic Philosophy of Pollution: A Critique
Authors: Norton G A , Parlour J W
Published: October 2006

The development of the economist's view of pollution is critically reviewed, especially the more recent theoretical and pragmatic contributions that attempt to deal with pervasive pollution effects. It is argued that the standpoint taken by most contributors is largely isolated from the view of the economic system as enclosed in a dynamic biospheric system, consisting of natural as well as social sub-systems. Since the solution to the pollution problem derived from this restricted economic perspective is regarded as unsatisfactory, more appropriate social goals associated with the holistic view of the pollution syndrome are suggested.
Factorial Ecologies: Oblique and Orthogonal Solutions. A Case Study of the New York SMSA
Authors: Hughes J W , Carey G W
Published: October 2006

The utilization of factor analytic methods in the investigation of the spatial structure of urban areas has raised several methodological concerns. Two of these issues are examined in this study: the validity of the orthogonal model, and the possibility of bias through boundary drawing.

This paper thus focuses on the effect of the choice of rotational technique upon the derived factor structures at three levels of metropolitan delineation—metropolitan area, city, and inner city sub-area. The rotational techniques are examined specifically in regard to dimensional interpretation and dimensional interrelationships at the three scales of observation. The findings have important methodological implication for the investigation of microregion structural variations.
Industrial Linkage Development Paths in Growth Poles: A Research Methodology
Authors: Moore C W
Published: October 2006

The research methodology developed in this article borrows heavily from process analysis and behaviouristic theories of the firm, and concentrates on the individual production and decision-making unit. The methodology is composed of two major parts: the first, a system for classifying the products, processes, and the technical and legal linkages between industrial plants according to the growth pole framework; and the second, a behaviouristic model of the linkage development of the firm within the growth pole. The first classification system for the growth pole draws on the techniques developed by Luttrell and Tosco in their research projects connected with the Mezzogiorno and North-west England. The second model postulates alternative linkage development paths which the firm may take both in terms of location and production—process structure over time.
An Explanation for the Observed Dispersion of Retail Establishments in Urban Areas
Authors: Dacey M F
Published: October 2006

The generalized formulation of the central focus cluster pattern by Dacey (1971) does not give specific results that are appropriate for empirical analysis of point patterns. One purpose of this paper is to give specific numerical properties for a special case of the central focus cluster pattern for which cluster centers have a circular normal distribution around the central focus and the members of each cluster are located at the cluster center. Another purpose is to establish that this restricted model yields the probability laws that empirical analysis indicates have good correspondence with the quadrat counts of retail establishments given by Artie (1959) and Rogers (1969).
Life in a Global Village
Authors: Adams J G U
Published: October 2006

The view is well established that the ‘earth shrinking’ consequences of developments in transport and communications represent progress. This view is disputed here, not primarily on the grounds that increasing mobility is closely associated with increasing physical pollution, but on the grounds that, by increasing the scale of society, it is alienating. Some mobility growth rates are charted; the paradox that these growth rates are associated with a widening gulf in communications is examined. The growth in the scale and complexity of society's problems produces a growing dependence on esoteric techniques of control. The growth of the technology of control abets the growth of more complexity and yet more techniques for controlling it. The result is a progressive widening of the gulf that separates the controllers from the controlled.
A Model of Students' Daily Activity Patterns
Authors: Tomlinson Janet , Bullock N , Dickens P , Steadman P , Taylor E
Published: October 2006

A model is described whose purpose is to predict the distribution of students in different activities and locations during the course of a typical day, depending on the effective restrictions imposed by the spatial distribution of buildings and sites, and by administrative and social constraints on the timing of activities. The model is of an entropy-maximising type; the data against which it is tested are drawn from time budget surveys made in two universities, using diary methods. A series of exploratory experiments made with the model are reported; these are designed to test the effects of alternative planning and administrative policies on activity patterns and the use of facilities.
Environmental Issues in Housing Habitability
Authors: Onibokun A G
Published: October 2006

The paper develops a new research method of analyzing and comparing the relative habitability of the housing environment. Eighteen public and private rental housing projects in Canada are examined. The study operationally and comprehensively characterizes the chain of environmental factors which determine and significantly influence tenants' relative satisfaction with their accommodation.
Residential Preferences: An Alternate View of Intraurban Space
Authors: Clark W A V , Cadwallader M
Published: October 2006

Maps of the intraurban residential preferences of a large sample of respondents in the Los Angeles metropolitan area are presented as an alternate way of viewing intraurban space. Some technical problems associated with the analysis of residential preferences are discussed, and an income constraint is introduced as an integral part of the analysis. The results suggest that it is possible to present a meaningful map of the urban area in terms of residential preferences, and that the preference patterns displayed by minority groups indicate the importance of ethnic ties.
A Dynamic Interindustry Model for the Economic Analysis of Pollution Abatement
Authors: Rose A
Published: October 2006

A two-component model is presented for the analysis of the economic impact of pollution abatement. The primary component is a dynamic input-output system in which the structure of the economy is related to the level of environmental control as well as to time. A submodel, which consists of the various abatement activities within each industry, is used to explore the underlying nature of structural changes which take place as a result of changes in environmental regulations. The usefulness of the overall model for policy and planning purposes is illustrated by an example in which the submodel is transformed into a linear-programming format.
The Effect of Aggregation on the Empirical Identification of Key Sectors in a Regional Economy: A Partial Evaluation of Alternative Techniques
Authors: Hewings G J D
Published: October 2006

The open nature of regional economies requires that careful attention be paid to the magnitude of intraregional interindustry relationships when decisions about the allocation of investment are made. A number of methods have been proposed for the purposes of identifying key sectors in a national economy using input–output models. This research reports on attempts to identify key sectors at the regional level using the 1963 and 1967 Washington State input–output models at various levels of aggregation. The lack of consistency of identification of key sectors by the various methods suggests that these approaches have limited utility at the regional level.
The Evaluation of an Empiric Model for an Urban Area
Authors: Stokes E B
Published: October 2006

A version of the Empiric model for an urban area is evaluated by examining its forecasting ability and the customary assumption that its parameters will remain constant over time. The model's forecasting ability is found to be quite poor and the assumption of parameter constancy is found to be invalid. The analysis casts grave doubts on the model's usefulness as an urban forecasting technique.
A Dynamic Balanced Regional Input—Output Model of Pollution Control
Authors: Chatterji M
Published: October 2006

One of the important problems in environmental management is the sharing of responsibility for cleaning the pollution. It may happen that a particular region may suffer pollution caused by the production of inputs and outputs which are consumed outside the region. This is also further complicated by the diffusion of pollutants over space. Within the framework of a balanced regional input–output model, a scheme for subsidy/tax has been presented so that interregional equity is maintained. Pollution control strategies must result in regional unemployment, migration, capital movements over space, changes in interregional competitive position, etc. A dynamic scheme is suggested so that, given some exogenous policy decisions and technological constraints, the activity levels of production in different regions are determined so that the system is in equilibrium.
Location of the Median Line for Weighted Points
Authors: Wesolowsky G O
Published: October 2006

This paper presents a method for finding a median line or lines for a set of weighted points on a plane. This line is defined as the one that minimizes the sum of weighted perpendiculars from the points to the line. Among the possible applications is the design of transportation corridors.
Entropy Maximization and Inferred Ideal Weights in Public Facility Location
Authors: Eastin R V
Published: October 2006

It is assumed that a planner entrusted with the decision to choose a site for a public service facility attempts to find that location which minimizes the summed weighted distances from the facility to each resident in the service area. An observer may be able to infer the set of relative weights assigned by the planner to the residents by observing the actual site choice and then solving an inverse Weber problem. However, in general, there can be many weighting schemes which are consistent with any given locational choice. This paper uses an entropy model to select the maximally least biased set of weights consistent with the limited information available and examines some of the properties of such a model.
Urban Land-Use Planning and Environmental Pollution
Authors: Werczberger E
Published: October 2006

This paper presents a linear-programming model for the formulation of a joint policy for land use and environmental pollution. The theoretical framework is an extension of the residential-location model originally suggested by Herbert and Stevens (1960). Environmental policy is introduced by setting environmental standards which can be spatially differentiated. According to the characteristics of the diffusion process and of the discharge location of the residuals into the environment, these standards can be expressed as the permissible concentration of pollutants, the total allowable pollutant emission, or the required treatment of the residuals. The model considers the locational choice of the various urban activities as well as the available technological alternatives for residual treatment. In the analysis of the dual it is shown that a policy which uses environmental standards can efficiently be implemented by using a system of emission or pollution licenses, performance standards, and zoning restrictions.
Dynamic Systems Modelling of the North-West Region: 2. Estimation of the Spatio-Temporal Policy Model
Authors: Bennett R J
Published: October 2006

This is the second of four papers which will be published in close sequence in this journal. It examines, first, a general economic-policy model, and second, existing data sources for the North-west region. The restrictions on the availability of data necessitate the specification of a more limited model of spatio–temporal economic structure. Five equations can be specified: for unemployment, employment, population, migration, and industrial movement, although policy variables are also included. Using the identification criteria and diagnostics discussed in the first part of this series, the lag structure of the model is then specified, and the parameters estimated by a two-stage least-squares procedure. The estimates from this model are then used to comment on patterns of regional dynamics and spatial policy.
Migration and the Dynamics of Multiregional Population Systems
Authors: Cordey-Hayes M
Published: October 2006

This paper gives a personal perspective on some models of national settlement systems, and draws attention to the importance of population migration within these models. It includes a discussion of the inadequacies of current models of interurban migration for the analysis of the dynamic interaction between the demographic and economic growth sectors of a system of postindustrìal cities. The paper is not, however, a review; instead, the aim is to obtain insights on how to progress towards a framework and a strategy for research that will usefully contribute to the analysis of national settlement policy.

Section 2 considers recent developments in multiregional demographic analysis and argues that these are of limited usefulness unless they are integrated with models of regional economic growth. Results are presented which show that multiregional demographic analyses are extremely sensitive to the assumptions about migration movements. Section 3 outlines three models which interrelate demographic and economic growth, and stresses the links between the two sectors. Each model considers population migration a key link, and two of them assume that the movement of workers provides an equilibrating mechanism between labour supply and demand. Section 4 questions the validity of this traditional approach to migration and argues that, for a system of postindustrial cities, a new approach is required (Morrison, 1973; Renshaw, 1972; Cordey-Hayes and Gleave, 1973; 1974). A conceptual framework, which emphasizes information flows, differential mobility, and inhomogeneity of labour, is sketched.

The final section concludes that no single model or approach provides a royal road to models of national settlement systems, owing to gaps in our understanding of the dynamics of interactions amongst cities. It is suggested that a hierarchy of models should be developed at varying levels of approximation.
On the Economic Structure of Strictly Hierarchical Central Place Systems
Authors: Beckmann M J
Published: October 2006

A strictly hierarchical central place system is characterized as follows: each city has a well defined rank; to a city of given rank there is assigned a fixed number of cities of the next lower rank; to cities of the lowest rank a rural hinterland is assigned. In this way a city of a given rank has associated with it an economic region consisting of all cities of lower rank and all rural areas assigned to it directly or indirectly. Let the set of economic activities in a city of given rank be a proper subset of the city of higher rank. Assume that production is characterized by constant input coefficients and that demand is described by proportional expenditure functions. The income (or value added) generated by each activity in any city of given rank can then be calculated. From this the income of cities, regions, and the population of cities and regions may be derived.
On the Inefficiency of Being Efficient
Authors: Goldberg M A
Published: October 2006

Decisionmaking in the industrialized nations of the western world increasingly can be characterized by its scale and speed of implementation. Another facet of decisionmaking is the narrowness with which problems are defined and the equally narrow range of alternatives sought for solution. This paper documents these elements of decisions and also sketches out a number of scenarios where such an approach has led to unexpected, and often undesirable, consequences.

An alternative view of complex decisions, based on these scenarios, is developed. It relies heavily not on optimization as its pivotal criterion but rather upon the persistence of the decisionmaking unit, which is ultimately our society. Examples are presented which illustrate the counterproductive nature of many optimizing solutions. The argument is made that in an uncertain world, such as the one in which we live, optimizing approaches to decisions cannot succeed in the longer run because their assumptions about the constancy of our world do not hold up. Accordingly, a more flexible framework is suggested which values the complexity and uncertainty of the socioecological systems within which we must operate. The stability of these systems is seen to be a critical consideration of decisions, and several aspects of stability are presented which have been overlooked in the past.

The paper is concluded with a number of points which it is argued should be explicitly accounted for in future decisionmaking frameworks. Among the points stressed are: the desirability of making small scale decisions and implementing them slowly; the need to acknowledge the limits of what is knowable and thus the role of uncertainty; the virtues of maintaining a diversity of components in our socioecological systems; and finally the need to keep decision options open.
A Predictive Model of Urban Stock and Activity: 1. Theoretical Considerations
Authors: Ayeni M A O
Published: October 2006

Urban systems are dynamic and hence require predictive models that incorporate the element of time more explicitly. Comparative static models of the Lowry type may be embellished by the use of the entropy-maximizing methodology and by slight reformulations of the equations by the introduction of simple lags. The result is a quasi-dynamic or dynamic model of urban spatial structure. This is the first of two papers, in which the issues involved in the construction of predictive models are discussed and the equation systems of the model developed. The operationalization of the concepts and the empirical development of the model for a Nigerian city will be discussed in the paper to follow.
Time Budgets: Extended Methodology and Application
Authors: Yeung Y M , Yeh S H K
Published: October 2006

As a planning and research tool, the time budget is sadly neglected and falls far short of its potential. Existing studies that apply to this methodology are limited in their focus on human activities and have overlooked time budgets as a means of comparing the life styles of people in different living environments. The results of two time-budget surveys of residents in an urban-fringe squatter area and high-rise public flats in the Republic of Singapore are reported, stressing those aspects that, at best, are usually paid lip service. An analysis of the various ways in which people in these divergent living environments used their time reveals important contrasts in life styles. Implications for urban planners are briefly drawn.
Urban Planning to Minimize Environmental Impact
Authors: Bammi D , Bammi D , Paton R
Published: October 2006

An optimizing land-use planning model (OPTPLAN) is used to minimize environmental impact. The development of the natural-resource objective function and natural-resource constraints is described. Application of the model to DuPage County, Illinois is shown. The model's output is transferred to maps and compared with a land-use plan obtained through conventional natural-resource methodology.
Restricted Lateral Movement: An Initial Test of the Locational Attachments Hypothesis
Authors: Poulsen M F
Published: October 2006

Directions of residential mobility can be classified in terms of lateral movement around, and radial distance from, the Central Business District. In this paper, an examination of the explanations of restricted lateral movement, by adopting the argument that all major elements of the migration process have to be examined, is presented. As a result of the findings reported it is concluded that the explanation is one of locational attachments.
New Entropy Models in the Social Sciences. 1. Elementary Residential-Location Models
Authors: Dacey M P , Norcliffe A
Published: October 2006

This paper is concerned with the development of new entropy models for use in the social sciences and, in particular, with residential location in a spatial-interaction context. The inconsistencies and limitations inherent in some of the existing spatial-interaction entropy models used to describe activities taking place in urban and regional systems are first discussed, and new location models that have none of these inconsistencies are then developed. The new models describe the location of households about a city centre and, more generally, about a given distribution of jobs. The models take due account, in a consistent fashion, of any zonal-capacity constraints. The use of the models is illustrated with suitable data.
A Comparison of Observed and Hypothetical Choice Behaviour
Authors: Massam B H , Bouchard D
Published: October 2006

Analysis of a data set consisting of questionnaire interviews with actual and potential emergency patients in Montreal revealed that patterns of hospital choice for minor accidents and illnesses differ markedly in hypothetical- and observed-choice situations. General agreement at the aggregate level tends to conceal a variety of behaviour patterns among individuals and subgroups. It is suggested that decision rules derived from observation of actual choice behaviour are more consistent and reliable for planning use than are responses to hypothetical-choice questions.
Urban Residential Analysis: 2. Spatial Consumer Equilibrium
Authors: Papageorgiou G J , Mullally H
Published: October 2006

Part 1 of this two-part series was concerned with the description and analysis of elements that transcend diverse urban structures of the ‘service’ type. The conclusions were general and abstract. Beyond this unified realm a more detailed description of urban form requires additional assumptions. The nature of such assumptions defines urban form within the confines of positive or normative analysis. Here the additional assumptions define spatial equilibrium within an ‘open’ city. Special cases of such equilibria have been studied extensively. In contrast part 2 develops the general case of a multicentre multiincome city. The properties of spatial-equilibrium bid-rent functions, their synthesis to a composite land-value surface, as well as the properties of this composite, are analyzed in section 1. The next section examines residential land-use patterns generated in a ‘service’ city. Such patterns turn out to be dramatically different from those of other urban types. Section 3 discusses the complex land-value and density surfaces that unfold over the landscape. Finally, section 4 provides what is probably the only analytically solved example of a spatial-equilibrium model related to a hierarchy of centres and to a continuous distribution of incomes over a continuous space.
Application of a New Nonlinear Programming Code with Decomposition to the Regional Wastewater-Collection and Treatment-Location Problem
Authors: Padgett L R , Montgomery A H , Romino L
Published: October 2006

A new, highly reliable nonlinear programming algorithm is coupled with decomposition to find the optimal solution to a regional sewage-treatment system for an area in Monongalia County surrounding Morgantown, West Virginia. A regional model with trade-offs between the cost of transporting wastewater to centrally located plants for treatment and the economies of scale accruing to large centralized treatment plants is developed. Possible cost savings of an optimal system are demonstrated.
Solid-Waste Management: A Test of Alternative Strategies Using Optimization Techniques
Authors: Greenberg M , Caruana J , Krugman Beth
Published: October 2006

The objective of this paper is to determine how residential solid waste has been and could be disposed of or reused in metropolitan regions. By means of optimization techniques, the authors examine the economic efficiency of landfilling, energy and materials recovery, and waste-transportation technologies at centralized and dispersed sites. The results indicate that dry-fuel technology is the most efficient system for the near future. Pyrolysis, incineration, and landfilling are less efficient systems in metropolitan regions which are running out of inexpensive landfill space. Northern New Jersey is used as a case study.
Land-Use Plan Design via Interactive Multiple-Objective Programming
Authors: Barber G M
Published: October 2006

An urban land-use plan-design model is cast as a multiple-criterion optimization problem and is solved by using a generalized interactive technique. Three different objectives are selected for use in a representative formulation: (1) the minimization of land-development costs, (2) the maximization of residential accessibility, and (3) the minimization of energy consumption in transportation. It is found that interactive multiple-objective programming represents an efficient way of generating compromise land-use plans which provide satisfactory levels for the various objectives. The approach is illustrated for a hypothetical planning problem for Germantown, Wisconsin, USA.
The Structure of Journeys and Nature of Travel Patterns
Authors: Hensher D A
Published: October 2006

The aim of this paper is to investigate at a conceptual level, with a limited amount of empirical evidence, the likely consequences on our present planning methodologies of taking into account the true structure of all journeys. A particular concern is the influence of changes in land-use configurations on the structure of journeys and the probable policy implications. A consideration of journey structure appears to offer one potentially promising procedure for relating land use and transport plans in a way that yields more realistic insights and policy in urban areas. The paper concludes with some suggestions for the way ahead.
Mode Choice, Transport Pricing, and Urban Form
Authors: Dendrinos D S
Published: October 2006

The paper examines, within the framework of the standard von Thünen type model with no congestion, the market equilibrium urban form under a regime of commuters who use both the auto and the transit modes, but with no transfers, for their journey to work. There is an extension, however, in that households are assumed to be operating under both an income constraint and a time constraint. The rent and density gradients are obtained in closed forms.

Comparative statics are performed, and some policies regarding parking fees, pricing, and investment in the two modes are tested. It is shown that the city may consist of three rings, where the residential location of the user of one mode is split by the residences of the users of the second mode.
The Spatial Arrangement of Urban Activities: A Simultaneous Location Model
Authors: Odland J
Published: October 2006

The spatial patterns of urban activities are treated as the outcome of a balance between economic conditions that reward spatial concentration of employment activity on the one hand but favor spatial dispersion of residences on the other. The balance between these two sets of conditions is mediated by the cost of commuting. These three elements are formalized in terms of a mathematical-programming model that determines simultaneously the location patterns of employment, residential activity, and commuting. The solution conditions lead to a single-equation model which estimates the distances between zones in a city on the basis of their residential and employment densities. This version is fitted to data for four US cities. Estimates derived from the single-equation model can be resolved into two-dimensional maps of the zones by multidimensional scaling, and maps of the four cities, based on the estimated equations, are obtained and compared with the actual maps of the cities. The results indicate that the estimated parameters are congruent with the actual spatial arrangements of the cities.
Subjectivity and Objectivity in Landscape Evaluation
Authors: Price C
Published: October 2006

Complex functional form makes it difficult to establish the universality of relationships between trip distributions and landscape features such as pylons. Subjective judgement of aesthetic quality can be made more rigorous by relating it to holiday expenditure and the preference for general quality, as revealed by trip distributions. Ascribed values should be discounted according to factors more directly relevant than investment rate of return. Familiarity and uniqueness of landscapes obstruct substitution for despoiled ones, and introduce values not revealed by trip-distribution analysis. Research might reach a more effective compromise from a subjective than from an objective starting point.