http://hdl.handle.net/10045/17289 Thu, 20 Jun 2013 10:52:00 GMT 2013-06-20T10:52:00Z http://rua.ua.es:80/dspace/retrieve/70706/logo_i2rc50x60.png http://hdl.handle.net/10045/17289 http://hdl.handle.net/10045/27927 Título: Los mercados locales de trabajo españoles: una aplicación del nuevo procedimiento británico Autor/es: Casado Díaz, José Manuel; Martínez Bernabeu, Lucas; Flórez Revuelta, Francisco Fri, 01 Jan 2010 00:00:00 GMT http://hdl.handle.net/10045/27927 2010-01-01T00:00:00Z http://hdl.handle.net/10045/27923 Título: A memetic algorithm for the delineation of local labour markets Autor/es: Flórez Revuelta, Francisco; Casado Díaz, José Manuel; Martínez Bernabeu, Lucas; Gómez Hernández, Raúl Resumen: 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. However, the percentage of invalid solutions was still very high. In this paper we improve that evolutionary algorithm through the inclusion of (i) a reparation process, that allows every invalid individual to fulfil the constraints and contribute to the evolution, and (ii) a hillclimbing optimisation procedure for each generated individual by means of an appropriate reassignment of some of its constituent units. We compare the results of both techniques against the previous results and a greedy method. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/10045/27923 2008-01-01T00:00:00Z http://hdl.handle.net/10045/27922 Título: An evolutionary approach to the delineation of functional areas based on travel-to-work flows Autor/es: Flórez Revuelta, Francisco; Casado Díaz, José Manuel; Martínez Bernabeu, Lucas Resumen: 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 overlap 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, which are 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 that is considered to be representative given the density and variety of travel-to-work patterns 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 convergence process. The robustness of the solutions, something crucial in a research and policy-making context, is also discussed in the paper. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/10045/27922 2008-01-01T00:00:00Z http://hdl.handle.net/10045/27920 Título: An evolutive approach for the delineation of local labour markets Autor/es: Flórez Revuelta, Francisco; Casado Díaz, José Manuel; Martínez Bernabeu, Lucas Resumen: This paper presents a new approach to the delineation of local labour markets based on evolutionary computation. The main objective is the regionalisation of a given territory into functional regions based on commuting flows. According to the relevant literature, such regions are defined so that (a) their boundaries are rarely crossed in daily journeys to work, and (b) a high degree of intra-area movement exists. This proposal merges municipalities into functional regions by maximizing a fitness function that measures aggregate intra-region interaction under constraints of inter-region separation and minimum size. Real results are presented based on the latest database from the Census of Population in the Region of Valencia. Comparison between the results obtained through the official method which currently is most widely used (that of British Travel-to-Work Areas) and those from our approach is also presented, showing important improvements in terms of both the number of different market areas identified that meet the statistical criteria and the degree of aggregate intra-market interaction. Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/10045/27920 2006-01-01T00:00:00Z