Yasushi Asami

An empirical evaluation of spatial regression models

Conventional statistical methods are often ineffective to evaluate spatial regression models. One reason is that spatial regression models usually have more parameters or smaller sample sizes than a simple model, so their degree of freedom is reduced. Thus, it is often unlikely to evaluate them based on traditional tests. Another reason, which is theoretically associated with statistical methods, is that statistical criteria are crucially dependent on such assumptions as normality, independence, and homogeneity. This may create problems because the assumptions are open for testing. In view of these problems, this paper proposes an alternative empirical evaluation method. To illustrate the idea, a few hedonic regression models for a house and land price data set are evaluated, including a simple, ordinary linear regression model and three spatial models. Their performance as to how well the price of the house and land can be predicted is examined. With a cross-validation technique, the prices at each sample point are predicted with a model estimated with the samples excluding the one being concerned. Then, empirical criteria are established whereby the predicted prices are compared with the real, observed prices. The proposed method provides an objective guidance for the selection of a suitable model specification for a data set. Moreover, the method is seen as an alternative way to test the significance of the spatial relationships being concerned in spatial regression models.

The External Effects of Local Attributes on Living Environment in Detached Residential Blocks in Tokyo

Measuring environment attributes in monetary terms is an effective approach for evaluating living environments and planning. This paper presents a study employing a hedonic pricing model on the externalities of local attributes in detached residential blocks in Tokyo. Results show that a group of local attributes, including both attributes of individual lots and of local districts, exert stable external effects. Moreover, many of these effects are changing with the size of land lot. These findings provide important information for urban planning and design in detached residential blocks. In the paper, the sub-division of land lots, an event arousing much concern in recent years, is analysed and concepts on facilitating local parks are suggested.

A game-theoretic approach to the division of profits from economic land development

Abstract The present paper analyzes a very simple class of land-development games in which m developers individually seek to rent k contiguous land units from a set of n contiguous landowners. A notion of ‘admissible allocations’ is introduced to uniquely identify the set of ‘positive-profit participants’. Due to the contiguity of land, some land rents are seen to be positive even though the ‘bid rent’ for the land is zero.

Optimizing urban land use allocation for planners and real estate developers

Abstract In this paper, we use genetic algorithm based optimization models for urban land use allocation. We consider a multi-objective function for the planners, which simultaneously maximizes land prices and reduces incompatibility among adjacent land uses for an area. Land price of each and every plot of real estate developer is also optimized in response to the rules set by city development authorities. The differences in opinions of these two stakeholders are highlighted for a case study area of Bangladesh. The ultimate goal is to look for a computationally easy and efficient tool for generating and evaluating feasible land use plans to facilitate the allocation decision.

On the foundations of land use theory: Discrete versus continuous populations

Abstract Urban economists and location theorists have long employed land use models with a continuum of agents distributed over a continuum of locations. However, these continous models have been criticized on behavioral grounds in that individual households can consume only zero amounts of land in equilibrium. Hence the central purpose of this paper is to propose an alternative interpretation of these continous models as limiting approximations of discrete population models. In particular, it is shown that for large population sizes, the population distributions of the classical continuous model uniformly approximate the equilibrium population distributions generated by an appropriately defined class of discrete population models.

Sequential location--allocation of public facilities in one- and two-dimensional space: Comparison of several policies

The present paper examines the sequential location—allocation problems of public facilities in one- and two-dimensional space under several policies. It is shown that the efficiency loss due to the adoption of a myopic policy is not so large, contrary to common belief, provided that the efficiency can be measured by the total transportation cost of users and by the total capacity of facilities. If the total serving area is “sufficiently narrow”, then the spatial allocations of optimal solutions in two-dimensional problems can be closely approximated by those in one-dimensional problems.

Evaluating Land-Use Restrictions concerning the Floor Area Ratio of Lots

In Japanese city planning, the effective floor area ratio (FAR) of land lots, or housing density, is delimited by zoning and restrictions on the form of buildings (shape controls). To evaluate this system comprehensively, the authors analyze how the maximum allowable FAR (effective FAR) of residential lots affects land prices with a hedonic approach. Based on data on Tokyo, the analysis reveals that lots with an effective FAR of less than 110%, or between 170% and 210%, were significantly cheaper than those with an effective FAR of between 110% and 160%. The result for the low effective FAR group was explained by restrictions on floor space, and the result for the 170% to 210% group applied to areas with relatively unattractive landscape. Further examination showed that the FAR currently specified by zoning is more often effective when it is low, and that restrictions in the form of shape controls are more often effective when the effective FAR is high. These analyses provided criteria for evaluating the current land use control system. Based on the results, concrete proposals are made for improving the regulation system.

CHARACTERIZATION OF THE STREET NETWORKS IN THE TRADITIONAL TURKISH URBAN FORM

In this paper, we use the question “what is the true nature of traditional street networks in Turkish cities?” to test different quantitative methods of urban morphological analysis. Traditional Turkish street networks are characterized by discriminant functions of several space-syntax-related indices, as well as by image-analysis and graph-theoretical indices. A set of space-syntactic indices is found to be powerful enough to distinguish the traditional street network among others, particularly axial ringiness, implying that the formation of large blocks is a typical feature. The relative abundance of closed-end edges is found to be another important feature of the traditional street network.

Influence of spatial features on land and housing prices

The analysis of hidden spatial features is crucial for the improvement of hedonic regression models for analyzing the structure of land and housing prices. If critical variables representing the influence of spatial features are omitted in the models, the residuals and the coefficients estimated usually exhibit some kind of spatial pattern. Hence, exploration of the relationship between the spatial patterns and the spatial features essentially leads to the discovery of omitted variables. The analyses in this paper were based on two exploratory approaches: one on the residual of a global regression model and the other on the geographically weighted regression (GWR) technique. In the GWR model, the regression coefficients are allowed to differ by location so more spatial patterns can be revealed. Comparison of the two approaches shows that they play supplementary roles for the detection of lot-associated variables and area-associated variables.

Evaluation of the shape of residential lots in land-readjustment projects

Abstract Land-readjustment projects are redevelopment projects to increase the value of lots by reshaping lots and supplying community facilities. In such projects, appropriate evaluations of residential lots, depending on their shapes, are indispensable. This paper proposes a system of evaluation functions for rectangular lots that satisfies the superadditivity property, which seems to be a reasonable requirement in such projects.