THE COMPARATIVE STATIC RESPONSE OF RENTAL HOUSING TO A PRICE CHANGE: INFLATION AND GOVERNMENT POLICY*

ABSTRACT. A two period consumer choice model is presented in which housing is treated as a quality differentiated good. The short-run comparative static response of rental housing to a price change is examined via an example, an exogenous increase in the inflation rate. Two stylized facts are alternately used; interest income is taxed, and interest rate ceilings are imposed on small savings deposits. The partial equilibrium distributional impact of inflation, in the context of rental housing markets, is also discussed.     

Analysis of Dynamic Spatial Interaction Models by Means of Optimal Control

This paper deals with the design of general classes of dynamic spatial interaction models. On the basis of a general (well-behaved) multiperiod objective function and of a dynamic model representing the evolution of a spatial interaction system, an optimal control model is constructed. Particular attention is given to the equilibrium and stability conditions. It turns out that it is possible to identify steady-state solutions for a dynamic spatial interaction model. Furthermore, it can also be demonstrated that the entropy model is a specific case of this spatial interaction system. A simple illustration for urban dynamics is given as well.     

Mode Choice,Commuting Cost,and Urban Household Behavior*

Abstract. In this paper, we extend the partial equilibrium urban model of DeSalvo (1985) to include mode choice. DeSalvo demonstrated that the urban model of Muth (1969) was robust to the extension to leisure choice. We show that the model is robust to mode choice as well. In addition, we derive the comparative static results that commuters choose higher speed modes for longer commutes, at higher wage rates, with greater tastes for housing, and with lower housing prices. Also, for a given distance commuted, we derive the comparative static result that commuters chose shorter duration commutes at higher wage rates. Whereas it is typically assumed that marginal commuting cost is positive and non‐increasing with distance, we derive these results. Moreover, we derive the results that marginal commuting cost rises with an exogenous increase in housing price and falls with increased tastes for housing. We also explore the effects of exogenous commuting‐cost changes on the endogenous variables of the model. The remaining comparative static results on housing consumption and location are qualitatively the same as in DeSalvo.     

How Does Economic Development in Eastern Europe Affect Austria's Regions? A Multiregional General Equilibrium Framework

The paper quantifies regional welfare effects arising from the increasing trade flows between Austria and its Eastern neighbors after the opening up of Eastern Europe. We calibrate a static multiregional Computable General Equilibrium (CGE) model with benchmark data from 1994 for Austria, subdivided into nine Federal Provinces. The regions are linked by trade flows with the four Eastern neighboring countries and with the rest of the world. We simulate the effects of the increase of trade interpenetration as observed between 1989 and 1999 in a comparative static analysis. Regional welfare effects under fixed and flexible wages are presented. We also compare national CGE results with estimates obtained in a simple partial equilibrium approach.     

Stability of Spatial Equilibrium*

Abstract. Asymptotic stability of equilibrium is often difficult to know when the number of variables exceeds four, since all eigenvalues of the Jacobian matrix are not analytically solvable. However, we obtain stability conditions for a general class of migration dynamics without computing eigenvalues. We show that a spatial equilibrium is stable in the presence of strong congestion diseconomies, but unstable in the presence of strong agglomeration economies. We also show existence of a stable equilibrium in the case of negligible interregional externalities, which is applicable to club goods, local public goods, and new economic geography.     

SEARCH FRICTIONS,UNEMPLOYMENT, AND HOUSING IN CITIES: THEORY AND POLICIES

We propose an urban search‐matching model with land development. Wages, unemployment, prices of housing and land are endogenously determined. We characterize the steady‐state equilibrium and then discuss the issue of efficiency. To explore interactions among markets, we implement comparative static analysis. We also consider three policies: an entry‐cost policy that reduces firms' entry, a transportation policy that reduces commuting costs, and a housing policy that decreases rental prices. We find that the transportation and housing policies are more efficient if the unemployment rate is low, while the entry‐cost policy is more efficient if the unemployment rate is high.     

INTERDEPENDENT BEHAVIOR WITH RELOCATION COSTS: THE COMPARATIVE STATICS OF SPATIAL HISTORY*

Relocation costs are a form of sunk costs because they are relevant to new entrants, not to agents at their existing locations. With sufficiently high relocation costs, initial (historically given) locations and other conditions determine the equilibrium assignment of agents to locations. Comparative static results depend on initial conditions, i.e., history matters and historical persistence can be characterized. The model suggests empirically-relevant results which can be tested by collecting data on relocation and transportation costs. For example, appropriate levels of these costs imply that suburbanization always occurs with the entry of new firms. Sequential entry strategies may be adopted by existing firms which earn pure profits. This may be contrasted with traditional NUE models which predict changes in the boundaries of central zones.     

Comparing closed system, flow-through and fluid infiltration geochemical modelling: examples from K-alteration in the Ernest Henry Fe-oxide–Cu–Au system

Potassic alteration of rocks adjacent to, and within the Ernest Henry Fe‐oxide–Cu–Au deposit is used here as a test case to investigate fluid–rock interactions using various equilibrium dynamic geochemical modelling approaches available in the HCh code. Reaction of a simple K–Fe–(Na,Ca) brine (constrained by published fluid inclusion analysis) with an albite‐bearing felsic volcanic rock, resulted in predicted assemblages defined by (i) K‐feldspar–muscovite–magnetite, (ii) biotite–K‐feldspar–magnetite, (iii) biotite–quartz–albite and (iv) albite–biotite–actinolite–pyroxene with increasing rock buffering (decreasing log w/r). Models for isothermal–isobaric conditions (450°C and 2500 bars) were compared with models run over a T–P gradient (450 to 200°C and 2500 to 500 bars). Three principal equilibrium dynamic simulation methods have been used: (i) static closed system, where individual steps are independent of all others, (ii) flow‐through and flush, where a part of the result is passed as input further along the flow line, and (iii) fluid infiltration models that simulate fluid moving through a rock column. Each type is best suited to a specific geological fluid–rock scenario, with increasing complexity, computation requirements and approximation to different parts of the natural system. Static closed system models can be used to quickly ascertain the broad alteration assemblages related to changes in the water/rock ratio, while flow‐through models are better suited to simulating outflow of reacted fluid into fresh rock. The fluid infiltration model can be used to simulate spatially controlled fluid metasomatism of rock, and we show that, given assumptions of porosity relationships and spatial dimensions, this model is a first‐order approximation to full reactive transport, without requiring significant computational time. This work presents an overview of the current state of equilibrium dynamic modelling technology using the HCh code with a view to applying these techniques to predictive modelling in exploration for mineral deposits. Application to the Ernest Henry Fe‐oxide–Cu–Au deposit demonstrates that isothermal fluid–rock reaction can account for some of the alteration zonation around the deposit.     

Dome of the Basilica of Santa Maria Degli Angeli in Assisi: Static and Dynamic Assessment

This study presents the results of the static and dynamic assessment of the dome of the Basilica of Santa Maria degli Angeli in Assisi, designed by Galeazzo Alessi. The first section is devoted to an overview of the masonry domes designed by the Italian architect and focuses on the structural solutions adopted in the several cases described to better understand Alessi’s designing skills. In the second part, the drum-dome system is analyzed in order to attain a structural assessment. The static assessment is performed by means of limit analysis and finite element model approaches with non-linear mechanical behavior. The obtained results are consistent with the detected crack pattern and confirm the suitability of the reinforcement steel rings applied to the drum. The seismic assessment has been performed by response spectrum analysis. Due to the lack of specific information, a probabilistic approach for the material mechanical properties was used. The results obtained highlight an adequate seismic response of the structure that can be attributed to the dynamic properties of the slender drum-dome system. This finding justifies the good performance of the structure during the seismic events of 1832 and 1997.     

Migration Under Uncertainty: “Try Your Luck” or “Wait and See”

Two types of uncertainty enter into the migration decision. First, current conditions in the destination region may not be observable. Second, the future evolution of conditions in both the origin and destination regions may be unknown. The first type of uncertainty can encourage speculative or “try your luck” migration, whereas uncertainty about the future acts in the opposite direction, deterring relocation. This paper presents a dynamic optimizing model of migration that incorporates both types of uncertainty. The model shows that in equilibrium uncertainty about the future is likely to be more important than uncertainty about present conditions in the decision to relocate.     

Hydrothermal,multiphase convection of H2O‐NaCl fluids from ambient to magmatic temperatures: a new numerical scheme and benchmarks for code comparison

Thermohaline convection of subsurface fluids strongly influences heat and mass fluxes within the Earth's crust. The most effective hydrothermal systems develop in the vicinity of magmatic activity and can be important for geothermal energy production and ore formation. As most parts of these systems are inaccessible to direct observations, numerical simulations are necessary to understand and characterize fluid flow. Here, we present a new numerical scheme for thermohaline convection based on the control volume finite element method (CVFEM), allowing for unstructured meshes, the representation of sharp thermal and solute fronts in advection‐dominated systems and phase separation of variably miscible, compressible fluids. The model is an implementation of the Complex Systems Modelling Platform CSMP++ and includes an accurate thermodynamic representation of strongly nonlinear fluid properties of salt water for magmatic‐hydrothermal conditions (up to 1000°C, 500 MPa and 100 wt% NaCl). The method ensures that all fluid properties are taken as calculated on the respective node using a fully upstream‐weighted approach, which greatly increases the stability of the numerical scheme. We compare results from our model with two well‐established codes, HYDROTHERM and TOUGH2, by conducting benchmarks of different complexity and find good to excellent agreement in the temporal and spatial evolution of the hydrothermal systems. In a simulation with high‐temperature, high‐salinity conditions currently outside of the range of both HYDROTHERM and TOUGH2, we show the significance of the formation of a solid halite phase, which introduces heterogeneity. Results suggest that salt added by magmatic degassing is not easily vented or accommodated within the crust and can result in dynamic, complex hydrologies.     

SPATIAL ASYMMETRIC DUOPOLY WITH AN APPLICATION TO BRUSSELS' AIRPORTS*

ABSTRACT In this paper, the problem of a city with access to two firms or facilities (shopping malls, airports, commercial districts) selling a differentiated product (shopping, flights) and/or offering a differentiated workplace is studied. Transport connections to one facility are congested. A model is presented for this asymmetric duopoly game that can be solved for a Nash equilibrium in prices and wages. A comparative statics analysis is used to illustrate the properties of the equilibrium. A numerical model is then applied to the two Brussels airports. Three stylized policies are implemented to address the congestion problem: expansion of transport capacity, congestion pricing, and a direct subsidy to the uncongested facility. Our results indicate that the degree of intrinsic differentiation between the two firms is crucial in determining the difference in profit and market share. Price and wage differences also depend on trip frequency and consumer preferences for diversity. Congestion pricing is the most effective policy tool but all three options are shown to have attractive attributes.     

Land Absorption in U.S. Metropolitan Areas: Estimates and Projections from Regional Adjustment Models

This article adapts a regional adjustment model to estimate and project the spatial outcome of population and employment growth in U.S. metropolitan areas. The three-equation multiplicative model of population change, employment change, and land absorption is estimated using three-stage least squares to account for endogeneity among the dependent variables and contemporaneous correlation across the system of equations. In addition to the core model, alternative specifications are estimated, imposing the initial conditions of size, land availability, and economic structure. The stability of the solutions is then examined using reduced-form equations estimated via the seemingly unrelated regression equations approach. The results reveal substantive evidence that population and employment growth are jointly determined, of how the two affect the outcome of land development, and, perhaps most importantly, stable and fractionally reasonable estimates at projected equilibrium points. Lastly, the adapted model controlling for the initial condition of land availability is used to project patterns of land consumption at equilibrium in 50 rapid-growth metropolitan areas.     

制备方法对土遗址重塑样稳定性的影响研究

土建筑遗址本体的保护受遗址土的物理、水理、力学及所处环境差异的影响，重塑样是替代土遗址测试其各种性质的重要手段，重塑样拌制土性质的稳定性是科学评价、对比分析试验研究的基础和前提。本研究基于不同拌制土的方法，通过观察、拍照、量取土团粒大小以及同条件制备样品的无侧限抗压强度等，综合评价不同拌制土方法的影响条件。研究发现，采用人工拌土、闷土时间在24 h的土所制的试样最具稳定性，随着闷土时间再增加，土样强度在逐渐降低。本研究为土建筑遗址室内试验研究和工程现场拌制土料提供理论参考和技术支撑。     

The Exclusion Theorem in the Weberian Space

In this paper we employ a unifying approach to examine the exclusion theorem in a Weberian space under various types of uncertainty: input price or output price uncertainty, transport rate uncertainty, and technology uncertainty. The novelty of our approach is the usage of second-order conditions and comparative static analysis in the derivation of conditions for thevalidity of the exclusion theorem. Our main results are new and some are generalizations of those obtained in prior studies.     

A Simple Model for Estimating Shocks in Unrestrained Building Contents in an Earthquake

Building contents that include cabinets housing electronic equipment are typically not rigidly secured to the floor, nor to the adjacent wall except in regions of high seismic activities. The behavior of unrestrained building contents in an earthquake is a cause of concern because of the consequence of damage to certain equipment or other forms of fragile items. Much of the research reported in the literature has been devoted to studying the rocking and sliding motion behavior of base-excited rigid objects and their risks of overturning. In contrast, this paper is concerned with estimating the impact acceleration that can be generated by the pounding of the rocking object onto the floor. Algebraic expressions for predicting the acceleration level, which can be translated into dynamic force values, are derived and illustrated by case studies. Importantly, the proposed expressions have been verified by comparisons with results from both simulated and physical experiments. In illustrating the use of the proposed analytical procedure, a parametric experimental study has been undertaken on a cushion material to study the sensitivity of its static and dynamic stiffness to changes in the boundary conditions of the cushion. The proposed calculation procedure, while simple to apply, can be used as a means of predicting shock and the dynamic forces that can be generated in an object in the course of the response to an earthquake.     

Alonso and the Scaling of Urban Profiles

How urban characteristics change with total population, their scaling behavior, has become an important research field since one needs to better understand the challenges of urban densification. Yet urban scaling research is largely disconnected from intra-urban structure, and this seriously limits its operationalization. In contrast, the monocentric model of Alonso provides a residential choice-based theory to urban density profiles. However, dedicated comparative static analyses do not completely solve how the model scales with population. This article bridges this gap by simultaneously introducing power laws for land, income and transport cost in the Alonso model. We show that the equilibrium urban structure of this augmented model matches recent empirical findings about the scaling of European population density profiles and satisfactorily represents European cities. This result is however not compatible with the observed scaling power of housing land profiles, and challenges current empirical understanding of wage and transport cost elasticities with population. Our results call for revisiting theories about land development and housing processes as well as the empirics of agglomeration benefits and transport costs.     

Subsoil Interventions Effect on Structural Seismic Response. Part II: Parametric Investigation

In the present article the effect of subsoil interventions on the response of soil-structure systems under strong earthquake shaking is studied. Several idealized configurations of commonly applied as well as innovative intervention techniques are examined, referring to increased or reduced stiffness of the initial subsoil conditions of the subsoil-foundation-structure system. Numerical analysis utilizing validated simulation procedures covers a large spectrum of structures and soil conditions. A parametric investigation of several key factors is also conducted. A comparative evaluation of the results in time and frequency domain is aiming in generalizing the conclusions to several earthquake and soil-structure combinations. Obtained results reveal a rather detrimental effect of the stiffness-increasing methods, whereas techniques related to modification of oscillation dynamic properties with flexible subsoil intervention schemes, present promising alternatives for an efficient mitigation of structural response to strong earthquakes.