The delineation of functional economic areas, or market areas, is a problem of large practical relevance, since the delineation of functional sets such as Economic Areas in the US, Travel-to-Work Areas in the United Kingdom, and their counterparts in other OECD countries are the basis of many statistical operations and policy making decisions at local levels. This is a combinatorial optimisation problem defined as the partition of a given set of indivisible spatial units (covering a territory) into regions characterised by being (a) self-contained and (b) cohesive, in terms of spatial interaction data (flows, relationships). Usually, each region must reach a minimum size and self-containment level, and must be continuous. Although this type of problems has been typically solved through greedy methods, a recent strand of the literature in this field has been concerned with the use of evolutionary algorithms with ad hoc operators. Although these algorithms have proved to be successful in improving the results of some of the more widely applied official procedures, they are so time consuming that cannot be applied directly to solve real-world problems. In this paper we propose a new set of group-based mutation operators featuring general operations over disjoint groups, tailored to tackle with that problem so that all the constraints are respected during the operation to improve efficiency. A comparative analysis of our results with those from previous approaches shows that our algorithm systematically improves them in terms of both quality and processing time, something of crucial relevance since it allows dealing with most large, real-world problems in reasonable time.
This paper presents a new approach to the delineation of local labor markets based on evolutionary computation. The aim of the exercise is the division of a given territory into functional regions based on travel-to-work flows. Such regions are defined so that a high degree of inter-regional separation and of intra-regional integration in both cases in terms of commuting flows is guaranteed. Additional requirements include the absence of overlapping between delineated regions and the exhaustive coverage of the whole territory. The procedure is based on the maximization of a fitness function that measures aggregate intra-region interaction under constraints of inter-region separation and minimum size. In the experimentation stage two variations of the fitness function are used, and the process is also applied as a final stage for the optimization of the results from one of the most successful existing methods, that used by the British authorities for the delineation of Travel-to-Work Areas (TTWAs). The empirical exercise is conducted using real data for a sufficiently large territory which is considered to be representative given the density and variety of travel -to-work patters that it embraces. The paper includes the quantitative comparison with alternative traditional methods, the assessment of the performance of the set of operators which has been specifically designed to handle the regionalization problem, and the evaluation of the conver gence process. The robustness of the solutions, something crucial in a research and policy-making context, is also discussed in the paper.
An evolutionary approach to the delimitation of labour market areas: an empirical application for Chile. Spatial Economic Analysis. Labour market areas (LMAs) are argued to represent a more appropriate policy framework than administrative units for the analysis of spatial labour market activity. This article develops LMAs for Chile by applying an evolutionary computation approach. This innovative approach defines LMAs through an optimization process by maximization of internal cohesion, subject to restrictions of minimum levels of self-containment and population. To evaluate the appropriateness of the LMAs, comparative analyses are performed between alternative delimitations based on different parameter configurations of the proposed method versus administrative boundaries and the most widely used method for official LMA delimitation, the travel-to-work areas method. KEYWORDS evolutionary computation; labour market areas; travel-to-work areas; Chile 摘要 界定劳动市场范围的演化方法:智利的经验应用。Spatial Economic Analysis. 在空间劳动市场活动的分析 上,劳动市场范围(LMAs)被认为较行政单位更能呈现合适的政策架构。本文透过应用演化计算方 法,为智利建立LMAs。此一创新方法,透过最大化内部凝聚力的最优化过程来定义LMAs,并受限于最 低程度的自我封闭与人口。为了评估LMAs的适切性,本文根据提出方法相对于行政疆界的不同参数组 合与 "通勤范围方法" 此一官方LMA界定最广为运用的方法,在不同的另类界定之间进行比较分析。 关键词 演化计算; 劳动市场范围; 通勤范围; 智利 RÉSUMÉ Approche évolutionnaire pour la délimitation de zones du marché du travail: une application empirique pour le Chili. Spatial Economic Analysis. Certains soutiennent que les zones du marché du travail constituent un
Given a territory composed of basic geographical units, the delineation of local labour market areas (LLMAs) can be seen as a problem in which those units are grouped subject to multiple constraints. In previous research, standard genetic algorithms were not able to find valid solutions, and a specific evolutionary algorithm was developed. The inclusion of multiple ad hoc operators allowed the algorithm to find better solutions than those of a widely-used greedy method. The experimentation process showed that the rate of success of each operator in generating good individuals is different and evolves with time. We therefore propose different adaptive alternatives that modify the probabilities of application of each operator throughout the evolutionary process, and compare the results of such adaptive approaches with previous results and a greedy method.
Labour market areas and other functional regions (FRs) are increasingly used within research and policy, but how FRs are best defined is an unresolved issue. This is important because the policy impacts, or the research results, will differ depending on the specific FR boundaries used. As a result of this sensitivity (termed the Modifiable Areal Unit Problem), quantitative metrics are needed so that differing sets of FR boundaries can be evaluated. To meet this need the paper firstly reviews the concept and use of labour market areasthe form of FRs most widely used in policyto identify relevant criteria for evaluating any regionalisation comprising a set of FRs. Next a range of potential measurable indicators for each of the criteria is defined. These candidate indicators are then exemplified by applying them to a huge number of alternative sets of FRs. From this empirical evidence a shortlist of preferred indicators is identified, creating a statistical 'toolbox' for evaluating sets of FRs. The paper ends by first sketching possible processes within which applying the indicators can help policy-makers with a decision over the appropriate set of FRs for a specific policy, before finally outlining some potential future research developments.
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