Population Oscillations in a Nonlinear Migration Model

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.     

A Note on the Mixed Geographically Weighted Regression Model*

Abstract. A mixed, geographically weighted regression (GWR) model is useful in the situation where certain explanatory variables influencing the response are global while others are local. Undoubtedly, how to identify these two types of the explanatory variables is essential for building such a model. Nevertheless, It seems that there has not been a formal way to achieve this task. Based on some work on the GWR technique and the distribution theory of quadratic forms in normal variables, a statistical test approach is suggested here to identify a mixed GWR model. Then, this note mainly focuses on simulation studies to examine the performance of the test and to provide some guidelines for performing the test in practice. The simulation studies demonstrate that the test works quite well and provides a feasible way to choose an appropriate mixed GWR model for a given data set.     

A Hierarchical Migration Model of Population Redistribution within a Central Place Hierarchy

A simple hierarchical migration model is proposed as a mechanism for the redistribution of population within a Christaller central place hierarchy. Given a predefined functional hierarchy, the migration process causes any initial population distribution to converge to an equilibrium distribution. Under certain special conditions, the equilibrium is identical to a central place population distribution derived from economic base concepts.     

A Decision-Making and Search Model For Intraurban Migration

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.     

Two-Way Migration in a Model with Identical Optimizing Agents

The simplest migration models based on maximizing behavior assume movement toward more desirable locations, and therefore ignore the large portion of moves in the "wrong" direction. Based on a model with identical, utility-maximizing agents, the analysis below shows that changes in relative location attractiveness can cause many migrants to move against the dominant stream. Even when the population distribution is stable and variation in wages and prices across locations reflect compensating differentials, so locations are equally attractive, individuals choose to move between locations, spending parts of their lives in different locations. These results stem from the role of consumption opportunities in migration decisions, highlighting processes that have been largely ignored.