Accommodating spatial correlation across choice alternatives in discrete choice models: an application to modeling residential location choice behavior

This paper presents a modeling methodology capable of accounting for spatial correlation across choice alternatives in discrete choice modeling applications. Many location choice (e.g., residential location, workplace location, destination location) modeling contexts involve choice sets where alternatives are spatially correlated with one another due to unobserved factors. In the presence of such spatial correlation, traditional discrete choice modeling methods that are often based on the assumption of independence among choice alternatives are not appropriate. In this paper, a Generalized Spatially Correlated Logit (GSCL) model that allows one to represent the degree of spatial correlation as a function of a multi-dimensional vector of attributes characterizing each pair of location choice alternatives is formulated and presented. The formulation of the GSCL model allows one to accommodate alternative correlation mechanisms rather than pre-imposing restrictive correlation assumptions on the location choice alternatives. The model is applied to the analysis of residential location choice behavior using a sample of households drawn from the 2000 San Francisco Bay Area Travel Survey (BATS) data set. Model estimation results obtained from the GSCL are compared against those obtained using the standard multinomial logit (MNL) model and the spatially correlated logit (SCL) model where only correlations across neighboring (or adjacent) alternatives are accommodated. Model findings suggest that there is significant spatial correlation across alternatives that do not share a common boundary, and that the GSCL offers the ability to more accurately capture spatial location choice behavior.     

跨国公司地区总部区位分布的特征与决定因素

文章以福布斯2008年排行榜全球2000家企业在中国设立的地区总部为研究对象,对其分布的特征及决定因素进行了研究。研究发现：在分布特征上,跨国公司地区总部在我国呈现出了地区集聚（96％集中于北京、上海两个城市）和国别集聚（73．9％集中于美日等6个国家）的特点;在决定因素上,最为显著的指标是城市大小与人口规模、第三产业占GDP比重和信息传递水平。研究还表明：跨国公司在我国选择非政治、商业、金融中心的城市时,表现得极为谨慎;同时,全球仅有34．3％的跨国公司在我国设立地区总部,说明世界各国在我国的投资强度目前仍较弱。     

区位商视角下的深圳优势产业实证分析

深圳经济特区成立30年以来,经济快速发展的同时也面临各种挑战。一方面,深圳内部面临着发展后劲不足、调控经济不力等多方面的问题;另一方面,外部经受着国内产业结构不断优化升级的考验。运用区位商对深圳的产业优势进行数量上的分析,可以为深圳产业结构的调整和转型提供科学指导,加速深圳的产业结构升级,以促使深圳的经济能够跃上新的台阶。     

森林生态区位价值评估初探——以龙江森工集团为例

按照生态区划的原则和方法,从生态环境现状、生态系统服务功能重要性和生态环境敏感性方面出发,构建了森林生态区位价值评估指标体系;采用层次分析法和模糊综合评判法,对龙江森工集团下属的4个林管局进行宏观评估,评估结果表明:4个林管局的森林生态区位价值的宏观价值排序为:伊春林管局管辖区>牡丹江林管局管辖区>合江林管局管辖区>松花江林管局管辖区。因此,建议在考虑森林建设资金投入时,应对森林生态区位价值高的地区有所倾斜。     

Can farmers extend their cultivation areas in urban agriculture? A contribution from agronomic analysis of market gardening systems around Mahajanga (Madagascar)

The rapid urbanization in developing countries implies an increasing pressure on urban agriculture for production. As most perishable food products come from this agriculture in close proximity to population concentrations, we analysed from an agronomic point of view how market-garden farmers can meet this increasing urban demand. This work took place in the case of Mahajanga, a secondary city with high increasing demographic rate on the Northwest coast of Madagascar. Based on preliminary surveys to characterize the farming systems (on a sample of 91 farms), 11 market-garden farmers chosen in the three main agricultural zones of the urban area were surveyed during two years. Surveys aimed at understanding their decision rules in crop choices, crop allocation to land and resource management, and to estimate their room for manoeuvre to increase their leafy vegetable areas under cultivation. The wholesalers and retailers who buy the farmers’ produce were also surveyed. A previous model of decision rules regarding crop location on farm territory was used to analyse the on-farm surveys and cartographic methods (GIS and on-farm manual representations) were used to quantify the land use. We highlight the following major points. (1) The leafy vegetable production in the surveyed farms already intensively uses land: farmers have complex decision rules largely depending on the water dynamics in the two main environments (lowlands and lakesides) where leafy vegetables are cultivated during the dry season. (2) The scarcity of farmers’ resources (labour money and water) leads to very little internal room for manoeuvre to increase the leafy vegetable production in the farms. (3) At territorial level however, some land reserve exist in one of the lowlands, but not on lakesides. The water availability for agriculture must be better informed through specialized hydrologic studies, as one of the main constraints nowadays to extend the agricultural area. An extrapolation to other cases of urban agriculture is then discussed as well as the role of agronomy to help urban planners to consider the place of agriculture in the urban development.     

Regional concentration of FDI in post-reform India: A district-level analysis

We analyze the concentration of foreign direct investment (FDI) in India at the district level, based on project-specific location choices since the reform program in the early 1990s. The decomposition property of the Theil index allows us to trace changes over time in the overall concentration of FDI to changes in concentration between and within subgroups of districts. We also differentiate between major types and sources of FDI. We find that FDI concentrated in a persistently decreasing number of districts. Concentration across those districts that received at least one FDI project within a given time interval also increased, but this increase leveled off in the more recent past. These trends hold for essentially all types and sources of FDI, while the average level of concentration varies considerably between these types and sources.     

建筑物定位和基础放线

建筑物的定位放线和基础放线是确定整个建筑工程平面位置的关键环节,施测中必须保证精度、杜绝错误,否则后果难于处理。     

MONOPOLISTIC LOCATION CHOICE IN A TWO‐SIDED HOTELLING MODEL

We analyse the optimal location choice of a monopolistic firm that operates two arbitrarily located platforms on a two‐sided market. By extending the traditional Hotelling framework, we show that the optimal platform locations are equivalent to the one‐sided benchmark if both sides are either restricted to single‐ or multi‐homing. In the mixed case (one side single‐homes, the other one multi‐homes), the optimal platform locations are in line with the respective symmetric case. If the monopolist is restricted to choosing the same location on either side of the market, the optimal locations are determined by the relative profitability of the market sides.     

Hybrid metaheuristic solutions to inventory location routing problem

This paper considers a supply chain network with multiple depots and geographically dispersed customers, each of which faces non-constant demand over a discrete planning horizon. The goal is to determine a set of depots to open, the delivery quantities to customers per period and the sequence in which they are replenished by a vehicle fleet such that the total system-wide cost is minimized. To solve it, first we construct a mixed integer program, and then propose a hybrid metaheuristic consisting of initialization, intensification and post-optimization. Results show that the proposed heuristic is considerably efficient and effective for many classical instances.     

吉林省文化创意产业规模、结构的时空分布和趋势——基于信息熵和区位熵的分析

文化创意产业已成为世界各国竞相发展的朝阳产业,对于区域转变经济增长方式、提升城市核心竞争力具有重要的实践意义。当前吉林省文化创意产业增加值以递增速度增加,法人单位、营业收入和从业人员比重增大,但是内部发展不平衡。1998年到2009年吉林省文化创意产业发展经历了三个阶段,并呈现一定收敛趋势,文化创意产业几个典型行业出现了一定的集聚,产业优势比较突出,但是由于行业发展的非均衡性导致了内部产业优势存在差异。