A GENERAL FRAMEWORK FOR THE INTEGRATION OF A LAND-USE MODEL WITH A TRANSPORTATION MODEL COMPONENT

Integrated land-use—transportation models are characterized as models in which the redistributive effects of one subsystem upon the other are explicitly defined and incorporated into the model's structure. At the core of integrated models is a linking procedure whose function is to transform the outputs of one model component into inputs for the other. Despite major efforts made in the past to build operational large scale integrated models, the structural properties of such models remain largely unexplored. This paper describes a general framework for an integrated model consisting of prototype model components. These are an iterative activity allocation model of the Garin-Lowry type, an equilibrium-assignment transportation network model, and a linking procedure. Given the level of analysis, this framework is shown useful for exploring the analytics of integrated models and, in particular, their equilibrium properties. By means of many simulation experiments based on an hypothetical numerical example, the operation of the model is demonstrated with an emphasis on the locational interpretation of the integration procedure. On the basis of the empirical results and considering the model's intrinsic assumptions, the following major findings can be cited. First, the effects of nontravel factors (such as basic employment and zonal attractions) upon activity distribution are stronger than effects caused by changes in the transportation system. The latter effects were found to yield nonlinear and, spatially, nonuniform changes in activity location which also tended to be larger in peripheral regions. Second, implicit in the specification of the integration procedure are behavioral assumptions regarding time-lags in locational adjustments made by activities in reaction to rising cost of travel. The present formulation implies that once located, activities do not revise their locational decisions despite substantial increases in travel costs. At the other extreme, all activities are permitted to readjust their locational preferences after the final interzonal travel costs are derived. The effect upon activity distribution of the latter specification is, of course, larger than that of the former, although less than the effect yielded by changes in nontravel factors. Regarding the equilibrium properties of the integrated system, both the theoretical and empirical analyses show that the entire model will converge into an equilibrium solution and that the corresponding trip patterns are also at equilibrium. These results will hold as long as the operation of the integrated models is completely controlled by the generation functions of the land-use model and the transportation model component only affects the spatial distribution of activities. Finally, the results from the simulation experiments indicate that the computed mean travel cost parameter tends to stabilize around a certain value as the level of demand for travel, within the system, rises. There is evidence that compensating changes in the location and composition of this demand are the main causes of this phenomenon. In light of these findings, it is possible to point to three key problems whose resolution could largely improve the predictive power of integrated models. First, it would be useful to define activity models in which the generation of activities is, among other things, a function of travel conditions. Second, currently formulated integrated models do not contain trip demand functions and, thus, demand for travel by an activity unit is regarded as completely inelastic. Third, different locating activities respond differently—over time and space—to changíng travel conditions, and models should, therefore, reflect explicitly such differences in activity behavior. A recent paper by Los [14], is an important contribution to the analysis of this issue.     

A MODEL OF SHOPPING CENTERS*

ABSTRACT In this paper, we propose a model of developers' strategies for tenant mixes and the locations of shopping centers (SCs). Consumers have preferences for product variety, and tenants in the SCs sell differentiated goods. The consumers can choose two shopping behaviors: patronizing one or both of the two SCs. We show that if the consumers have strong preferences for product variety, the SCs agglomerate to free‐ride on the rivals' product varieties, and the consumers patronize both SCs. On the other hand, if consumer preferences are weak, the SCs locate at different locations, and the consumers patronize one of the two SCs.     

Influence of Race on Household Residential Utility

Residential location choice models are an important tool employed by urban geographers, planners, and transportation engineers for understanding household residential location behavior and for predicting future residential location activity. Racial segregation and residential racial preferences have been studied extensively using a variety of analysis techniques in social science research, but racial preferences have generally not been adequately incorporated into residential location choice models. This research develops residential location choice model specifications with a variety of alternative methods of addressing racial preferences in residential location decisions. The research tests whether social class, family structure, and in‐group racial preferences are sufficient to explain household sensitivity to neighborhood racial composition. The importance of the interaction between the proportion of in‐group race neighbors and other‐race neighbors is also evaluated. Models for the San Francisco Bay metropolitan area are estimated and evidence of significant avoidance behavior by households of all races is found. The results suggest that social class differences, family structure differences, and in‐group racial preferences alone are not sufficient to explain household residential racial preference and that households of all races practice racial avoidance behavior. Particularly pronounced avoidance of black neighbors by Asian households, Hispanic neighbors by black households, and Asian neighbors by white households are found. Evidence of a decrease in household racial avoidance intensity in neighborhoods with large numbers of own‐race neighbors is also found.     

An Interactive Approach to the Central Facility Location Problem: Locating Pediatric Hospitals in Warsaw

Most of the conventional approaches to the central facility location problem neglect the interaction of analyst and decision-maker during the locational choice process. This paper presents a new interactive approach to the central facility location problem. It is assumed that the problem is formulated by an analyst as a multiobjective optimization problem. Then the decision-maker searches for a satisfactory solution working directly with the computer system. The interactive procedure was implemented on IBM-PC XT/AT as the decision support system DINAS (Dynamic Interactive Network Analysis System) which enables the solution of various multiobjective location-allocation problems. DINAS has been successfully used for solving a real-world planning problem, namely for finding locations for pediatric hospitals in the Warsaw region.     

Cognitive Maps and Spatial Behavior Of Consumers

Two multidimensional scaling algorithms are used to externally measure cognitive maps of supermarket locations for a sample of sixty-one supermarket shoppers. Issues raised in the construction of the cognitive maps are discussed. The relationship between the derived cognitive maps and consumer behavior is compared to the relationship between physical maps and consumer behavior. Behavior is shown to be more closely related to cognitive maps. Differences in cognitive maps are defined and canonically correlated with consumers' socioeconomic and locational attributes. While aggregate cognitive maps are closely associated with physical maps, there is substantial variation between individual maps. This variation is related to shopping behavior and selected socioeconomic and locational characteristics of consumers.     

A MODEL OF URBAN HOUSEHOLD BEHAVIOR WITH LEISURE CHOICE

This paper provides a complete comparative-static analysis of the simplest model of urban household behavior that incorporates time explicitly. Results involving the housing-price function and the effects on housing consumption and location (radial distance from the CBD) of exogenous changes in preferences for housing, housing price, and money costs of transportation are the same as in models not incorporating time explicitly. In addition, it is found that housing consumption and location are negatively related to commuting time, positively related to nonwage income, and ambiguously related (both a priori and empirically, for reasonable values of the relevant variables) to the wage rate.     

New patterns in the locational choice of immigrants in Spain

During recent years, Spain has experienced an important revolution in its migration flows. With the 2008–2013 Spanish financial crisis, the model of economic growth that attracted a large number of foreign people disappeared, and the entry of immigrants for reasons other than economic issues gained relevance. Linked with this phenomenon are the new patterns of locational choice across provinces and the variation in the nature of immigrants. In this paper, we examine the differential patterns and drivers of immigration across Spanish regions before and after the financial crisis. Special attention is paid to the question of how the characteristics of individual migrants influence their locational preferences. To answer this question, we use the Dirichlet multinomial regression model. The results obtained show a sharp change in the locational patterns of Spanish immigrants after the economic recession, confirming that traditional economic incentives are less relevant, while non-economic factors linked with a better lifestyle gain importance. They also reveal that, regardless of the economic conditions, network effects are strong. Finally, and what is probably more important for us, our estimates support the hypothesis that the locational preferences rely on the interaction between the immigrants’ characteristics and the underlying locational features.     

Interfacility Interaction in Models of Hub and Spoke Networks

Providers of transportation services may reduce their average unit costs by bundling flows and channeling them between hubs (also known as concentrators or routers). The resulting facility locations are interdependent because of the flows between them. This paper analyzes mathematical models of hub systems in an effort to enhance understanding of the optimal location of interactive facilities. The paper examines the behavior of solutions to several alternative models that require the location of a hub at either of two similar locations. A model employing a concave cost function favors the assembly of flows, penalizes fractional facility locations, and produces local minima that have integer facilities.     

The Optimal Nodal Location of Public Facilities With Price-Sensitive Demand

The purpose of this paper is to present some models for the location of public facilities in nodal networks that explicitly maximize social welfare by accounting for price-elastic demand functions. The models presented here are general; yet they are mathematically equivalent to the plant location problem and are therefore amenable to solution procedures developed for the plant location problem. The models presented here distinguish between two institutional environments that reflect the degree of power of the consumer to choose which facility to patronize. If consumers can be assigned arbitrarily to facilities and can be denied service, then the environment is one of public fiat. If consumers must be served at the facility of their choice, then a “serve-allcomers” environment exists. Separate models for each environment are specified, and the relationship between optimal assignments and pricing policies is developed.     

基于GIS的农村医疗设施空间可达性分析——以河南省兰考县为例

针对农村医疗设施空间分布的公平性问题,提出了使用GIS技术和空间可达性指标评估医疗设施的区域分布特征。以兰考县乡级以上卫生院为例,建立人口分布、医疗设施位置、行政区域等地理数据库,选择人均医疗资源分配、就医的最近距离、选择医院的机会、重力模型及改进的重力模型5个空间可达性模型,计算了各乡镇、各行政村的医疗设施可达性指标,并制作了相应的专题地图;在此基础上对医疗设施的空间布局进行了分析。空间可达性指标全面地反映医疗设施的空间分布特征,鉴别出资源分配较薄弱的区位,是农村医疗改革中设施规划和资源分配的重要依据。     

分散整合理论的实证研究——兼论信息通信技术在公司重新布局过程中的作用

通过对华北制药集团-华北药城-倍达药业公司的实际调研,描述了公司"空间重新布局"的一种过程:由市区分散地点向郊区经济技术开发区整合,我们将该过程概括为分散整合理论。它被市区原址土地价格和新布局地雇员安置因素所驱动。信息通信技术在重新布局过程中也起到了不可或缺的作用。     

SOLVING A THREE-DIMENSIONAL URBAN ACTIVITY MODEL OF LAND USE INTENSITY AND TRANSPORT CONGESTION*

ABSTRACT Recent developments in combining input-output and transportation planning models have made it possible to construct realistic comprehensive urban and regional activity models of land use intensity. These models form the basis for a rigorous approach to studying the interactions among urban activities. However, efficient computational solution methods for implementing such comprehensive models are still not available. In this paper, an efficient solution method for a nonlinear programming urban systems model is developed by combining Evans's partial linearization technique with Powell's hybrid method. The solution algorithm is applied to a small but realistic urban area with a detailed transportation network.     

Elimination of Source A and B Errors in p-Median Location Problems

The p-median problem is a powerful tool in analyzing facility location options when the goal of the location scheme is to minimize the average distance that demand must traverse to reach its nearest facility. It may be used to determine the number of facilities to site, as well as the actual facility locations. Demand data are frequently aggregated in p-median location problems to reduce the computational complexity of the problem. Demand data aggregation, however, results in the loss of locational information. This loss may lead to suboptimal facility location configurations (optimality errors) and inaccurate measures of the resulting travel distances (cost errors). Hillsman and Rhoda (1978) have identified three error components: Source A, B, and C errors, which may result from demand data aggregation. In this article, a method to measure weighted travel distances in p-median problems which eliminates Source A and B errors is proposed. Test problem results indicate that the proposed measurement scheme yields solutions with lower optimality and cost errors than does the traditional distance measurement scheme.     

Reliable p-Hub Location Problems in Telecommunication Networks

Hubs are critical elements of telecommunication and transportation networks because they play a vital role in mass traffic movement. The design of more reliable networks in hub-and-spoke systems is a critical issue because current networks, particularly many commercial Internet backbones, are quite vulnerable. In hub-and-spoke-type topologies, any malfunction at a hub may cause degradation of the entire network's ability to transfer flows. This article presents a new hub location problem, termed the reliable p-hub location problem , which focuses on maximizing network performance in terms of reliability by locating hubs for delivering flows among city nodes. Two submodels, the p-hub maximum reliability model and the p-hub mandatory dispersion model, are formulated. Based on hypothetical and empirical analyses using telecommunication networks in the United States, the relationship between network performance and hub facility locations is explored. The results from these models could give useful insights into telecommunication network design.     

HETEROGENEOUS TASTES AND RESIDENTIAL LOCATION*

ABSTRACT. In a simple urban model, where the only spatial distinction made is between center and suburb, we introduce a uniform distribution of preferences for land. Under a logarithmic utility function, we examine how the location and consumption decisions of individuals differ in consequence of their different preferences for land. Comparative statics indicate that the qualitative response of the city at equilibrium to changes in per capita income and transportation cost is not affected by the introduction of such heterogeneity. Possible extensions are also briefly discussed.     

HOTELLING'S “MAIN STREET” WITH MORE THAN TWO COMPETITORS*

ABSTRACT. I analyze oligopolistic competition among three or more firms located on Hotelling's (1929) Main Street and show that in contrast with Hotelling's duopoly, the symmetric locational structure supports a noncooperative equilibrium in prices. However, in a two-stage game of location choice in the first stage, and price choice in the second stage, there exists no subgame-perfect equilibrium where the whole market is served. This is because, starting from any locational pattern, firms have incentives to move toward the central firm. This strong version of the Principle of Minimum Differentiation destroys the possibility of a locational equilibrium. The results are a direct consequence of the existence of boundaries in the space of location. The sharp difference between these results and those of the standard circular model (whose product space lacks boundaries) shows that the general use of the circular model as an approximation to the line interval model may be unwarranted.     

THE INTRAMETROPOLITAN DISTRIBUTION OF R&D ACTIVITIES: THEORY AND EMPIRICAL EVIDENCE*

ABSTRACT. The paper presents a first attempt to unveil the underlying determinants of the geography of R&D labs within contemporary metropolises. To this end, the study builds on the premise of contemporary intraurban location and pricing models, suggesting that intraurban variations in property rents must reflect the imputed location preferences of firms or their workforce, as well as the extent to which local institutional constraints hinder these preferences. Against this background, the study proceeds with the econometric analysis of R&D property rent differentials within Greater Los Angeles. The empirical results indicate that access to research and nonresearch universities, transportation access, access to a host of worker amenities, as well as zoning and other local regulations play a critical role in shaping the intraurban geography of R&D labs.     

基于网络评论内容分析的餐饮消费者行为研究

网络评论是餐饮消费者潜意识中的消费偏好、感知等内在需求的外显投射,是其餐饮消费中最关注内容的外在显现。文章基于内容分析法,以大众点评网为例,对餐饮消费者的网络评论内容进行分析。结果表明:高价位餐厅消费者较低价位餐厅消费者的满意度评价更高,连锁餐厅消费者较单体餐厅消费者满意度更高;不同消费水平的消费者消费偏好有明显差异,低价位餐厅消费者更关注核心诉求,即食物本身的吸引力和价格高低,中价位餐厅消费者更关注服务,高价位餐厅的消费者更关注餐厅的综合品质,消费决策中更看重餐厅的环境、服务等非食物要素;从消费感知角度看,餐饮消费者最关注的前五位要素是:食物、环境、服务、价格和便利性。     

Regional urbanization and the selective growth of towns in North American regions

Despite the extensive discussion of urbanization in the North American past, the processes of selective growth among the various towns and cities, which comprise a regional urban system, remain obscured by the use of oversimplified explanations that neglect either functional and locational variations among the centres or the changing conditions of regional development. A generalized model of selective urban growth in newly settling regions is proposed which distinguishes three periods of development by characteristics of circulation and export activity. It emphasizes the changing implications of town locations (their nodality) as settlement expands and the bases of urban growth shift from commercial and local services to increasingly manufacturing. Discussion of the literature on regional urbanization, organized under five categories of traditional and more recent explanations of selective growth, not only points to the temporal and locational deficiencies which the model addresses, but also reveals the need for closer examination within a developmental framework of both the interdependencies of central place and mercantile bases of urban growth and the relationships between the emergence of manufacturing and city sizes.     

DRS. MUTH AND MILLS MEET DR. TIEBOUT: INTEGRATING LOCATION‐SPECIFIC AMENITIES INTO MULTI‐COMMUNITY EQUILIBRIUM MODELS*

ABSTRACT We consider the problem of integrating spatial amenities into locational equilibrium models with multiple jurisdictions. We provide sufficient conditions under which models that assume a single housing price in each community continue to apply in the presence of location‐specific amenities that vary both within and across communities. If these conditions are satisfied, the models, estimation methods, and results in Epple and Sieg (1999) are valid in the presence of (potentially unobserved) location‐specific amenities. We also show how to construct sufficient statistics that capture location specific spatial heterogeneity. We apply these techniques using data from the Pittsburgh metropolitan area. We find that these amenity measures capture proximity to important local employment centers as well as heterogeneity in school quality within a given school district.