Blas PelegrínPascual FernándezMaría Dolores García
825-843页
查看更多>>摘要：Abstract We address the location-price decision problem for firms that offer the same type of product and compete on delivered pricing. If firms set equilibrium prices at demand points, the problem can be seen as a location game for which the Nash equilibrium (NE) is used as solution concept. For spatially separated markets, with inelastic demand, there exists a NE and it can be found by social cost minimization, as happens in network and planar location. However, with price sensitive demand, the existence of a NE has not been proven yet and socially optimal locations may not be a NE. In this paper we show that a NE can be found in discrete and network location when demand is price sensitive. A Mixed Integer Linear Programming formulation is implemented in the best response procedure which allow to find a NE for a variety of demand functions. An empirical study with data of Spanish municipalities is performed in which the procedure is applied to 200 large size test problems with linear, quadratic, exponential and hyperbolic demand functions.
查看更多>>摘要：Abstract This article is a theoretical development of the gravitational model through an econophysical approach and physical tools. Therefore, this paper attempts to answer the following research question: “Can physics still contribute to the development of the gravitational model in economics?”. To tackle the question, this paper begins with an overview of the basic concepts of Newton’s universal gravitational theory, which was first applied in economics by the distinguished American scientist Isard (1954). Then the concepts and formulas of gravitational fields in physics will be translated into economics, thus reviving Isard’s original multilateralism through the elaboration of an extension of his model apt to describe the multilateralism and multi-country exchanges which characterize international trade. In this regard, the superposition principle of vector is used to offer vector analysis as a tool for mapping the interactions between the economic forces produced by the individual gravitational fields of different countries. A representation of the gravitational field of the European market will be provided. The field concept will extend the analysis from bilateral flows to the analysis of markets in two dimensions.
查看更多>>摘要：Abstract In this paper we propose a new competitive location model that considers the possible negative impact generated by competing facilities (such as cannabis dispensaries) on surrounding communities. The facilities cannot be located too close to the communities. Therefore, when distances are Euclidean, the facilities must be located at a point outside a set of circles centered at the communities. After formulating the model, a specially designed efficient algorithm that solves the single facility location problem within a given relative accuracy of optimality is constructed. A total of 128 instances are solved in a relatively short time. The largest instance of 10 existing competing facilities and 20,000 demand points was solved in less than 15 min of computer time. This new model opens avenues for future research by designing similar new models. Also, the algorithm designed in this paper can be applied to solving other location problems with outside of a set of circles constraints.
查看更多>>摘要：Abstract We consider the extension of a tractable NEG model with a quasi-linear log utility function to continuous space, and investigate the behavior of its solution mathematically. The model is a system of nonlinear integral and differential equations describing the market equilibrium and the time evolution of the spatial distribution of population density. A unique global solution is constructed, and a homogeneous stationary solution with an evenly distributed population is shown to be unstable. Furthermore, it is shown numerically that the destabilized homogeneous stationary solution eventually forms spiky spatial distributions. The number of the spikes decreases as the preference for variety increases or the transport cost decreases.
查看更多>>摘要：Abstract In this paper, we propose a new algorithm with inertial term and self-adaptive stepsize for solving the split variational inclusion problem (denoted by SVIP) in real Hilbert spaces. Under suitable conditions imposed on the parameters, we prove that our iterative scheme converges strongly to an element of the solution set of SVIP without the prior knowledge of the operator norm. Furthermore, we demonstrate that our suggested algorithm is efficient and achievable through some numerical experiments.
Xiaohu QianMingqiang YinFelix T. S. ChanKai Yue...
953-984页
查看更多>>摘要：Abstract Sustainability and flexibility are two main factors not being investigated explicitly by existing winner determination literature. From a fourth party logistics (4PL) provider’s point of view, an innovative sustainable-flexible winner determination problem under uncertain demand is particularly studied in transportation services procurement auctions. Based on a multi-attribute decision-making method, a linear constraint related to each bidder’s sustainability score and flexibility score can be constructed, and then we integrate an outside option policy to formulate a two-stage stochastic sustainable-flexible winner determination model. Subsequently, we develop an approximation approach to solve the model based on the principles of dual decomposition Lagrangian relaxation and the sample average approximation. Using an established generator to obtain random instances, the effectiveness and applicability of this research could be verified by conducting numerical experiments. Also, managerial insights can be obtained to provide decision support for running an efficient sustainable-flexible logistics system by using a Chinese 4PL firm’s real data.
查看更多>>摘要：Abstract We investigate the impact of multimarket contact on market power. We analyze this question in the U.S. airline industry where concomitant cross-market interactions among competing carriers abound. Collecting data from the U.S. Bureau of Transportation Statistics and exploiting a methodology that allows us to compute the Lerner index (proxy for market power), we find that multimarket contact between carriers has a U-shaped effect on market power. This suggests that there exists a threshold level of multimarket contact for carriers that compete across multiple markets to recognize their interdependences and begin to mutually forbear.
查看更多>>摘要：Abstract The accessibility of commercial centers (CCs) is a topic of great concern to consumers and planners. However, current research is mostly limited to the accessibility of a single traffic mode or rough road network, which makes it difficult to reflect on the real travel situation of residents. Based on the two-step floating catchment area (2SFCA) method framework, we propose an extended method for analyzing the accessibility of CCs in different transportation modes, making it suitable for commercial geography research. The Baidu Map API is used to provide more accurate, convenient, and realistic data for reliable estimates to pinpoint underserved populations. The results can be summarized as follows: First, the multimode R2SFCA method proposed fills the knowledge gap to the accessibility of a single traffic mode or or rough road network. Second, there exist significant differences in the spatial distribution of access to CCs for consumers in different transportation modes. The range of public transit along metro or bus routes shows a finger-like spatial distribution, while car traffic extends along external urban traffic routes and is time-sensitive because of traffic conditions. Third, changes in the average accessibility scores for all travel modes showed similar patterns with increasing threshold time. These accessibility measures help identify underserved areas and enable the development of policy recommendations for the optimal allocation of commercial facilities and resources.
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