9,330 research outputs found

    Modeling urban evolution by identifying spatiotemporal patterns and applying methods of artificial intelligence.Case study: Athens, Greece.

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    While during the past decades, urban areas experience constant slow population growth, the spatial patterns they form, by means of their limits and borders, are rapidly changing in a complex way. Furthermore, urban areas continue to expand to the expense of "rural” intensifying urban sprawl. The main aim of this paper is the definition of the evolution of urban areas and more specifically, the specification of an urban model, which deals simultaneously with the modification of population and building use patterns. Classical theories define city geographic border, with the Aristotelian division of 0 or 1 and are called fiat geographic boundaries. But the edge of a city and the urbanization "degree" is something not easily distinguishable. Actually, the line that city ends and rural starts is vague. In this respect a synthetic spatio - temporal methodology is described which, through the adaptation of different computational methods aims to assist planners and decision makers to gain an insight in urban - rural transition. Fuzzy Logic and Neural Networks are recruited to provide a precise image of spatial entities, further exploited in a twofold way. First for analysis and interpretation of up - to - date urban evolution and second, for the formulation of a robust spatial simulation model, the theoretical background of which is that the spatial contiguity between members of the same or different groups is one of the key factors in their evolution. The paper finally presents the results of the model application in the prefecture of Attica in Greece, unveiling the role of the Athens Metropolitan Area to its current and future evolution, by illustrating maps of urban growth dynamics.urban growth; urban dynamics; neural networks; fuzzy logic; Greece; Athens

    Simulation of urban system evolution in a synergetic modelling framework. The case of Attica, Greece

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    Spatial analysis and evolution simulation of such complex and dynamic systems as modern urban areas could greatly benefit from the synergy of methods and techniques that constitute the core of the fields of Information Technology and Artificial Intelligence. Additionally, if during the decision making process, a consistent methodology is applied and assisted by a user-friendly interface, premium and pragmatic solution strategies can be tested and evaluated. In such a framework, this paper presents both a prototype Decision Support System and a consorting spatio-temporal methodology, for modelling urban growth. Its main focus is on the analysis of current trends, the detection of the factors that mostly affect the evolution process and the examination of user-defined hypotheses regarding future states of the problem environment. According to the approach, a neural network model is formulated for a specific time intervals and each different group of spatial units, mainly based to the degree of their contiguity and spatial interaction. At this stage, fuzzy logic provides a precise image of spatial entities, further exploited in a twofold way. First, for the analysis and interpretation of up-to-date urban evolution and second, for the formulation of a robust spatial simulation model. It should be stressed, however, that the neural network model is not solely used to define future urban images, but also to evaluate the degree of influence that each variable as a significant of problem parameter, contributes to the final result. Thus, the formulation and the analysis of alternative planning scenarios are assisted. Both the proposed methodological framework and the prototype Decision Support System are utilized during the study of Attica, Greece?s principal prefecture and the definition of a twenty-year forecast. The variables considered and projected refer to population data derived from the 1961-1991 censuses and building uses aggregated in ten different categories. The final results are visualised through thematic maps in a GIS environment. Finally, the performance of the methodology is evaluated as well as directions for further improvements and enhancements are outlined. Keywords: Computational geography, Spatial modelling, Neural network models, Fuzzy logic.

    Spatial and multidimensional analysis of the Dutch housing market using the Kohonen Map and GIS

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    In this work the idea is to analyse general spatially identifiable housing market related data on Dutch districts (wijken) with the SOM (Kohonen Map) and a GIS. One of the authors has earlier carried out purely visual SOM analysis of that data, where patterns formed on a larger ‘map’ (the output matrix of the SOM) were used as a basis for classification of the Dutch housing market segments on a nationwide level. This way the SOM was used as a method for exploratory data analysis. Now we attempt a more rigorous method of determining the segmentation using a smaller ‘map’ size, in order to be able to export the SOM-output directly to a GIS-system to analyse it further. Two technical issues interest us: one, the robustness of the results – do the five basic housing market segments found in the earlier analysis prevail (we call these urban, urban periphery, pseudo-rural, traditional, and low-income segments); and two, which classes fit the real situation better and which worse, when using the RMSE for a measure of goodness? We also keep an eye on policy implications and aim at comparing our classifications with the ‘actual’ ones used in official discourse.

    Devolution as a means to adequate social safety nets?

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    Decentralisation is invariably among the recommendations that international organisations such as the World Bank make for an enhancement of social provisions, and particularly a better targeting of social assistance regimes, in Eastern and Central Europe. However, theoretical literature as wel as empirical research suggests that decentralisation is not by defintion a panacea, especially when it concerns the transfers of competencies in the matter of social protection systems. It is true that there are arguments to promote redistributive activity at lower levels of government but whith regard to policies aimed at redistribution and reducing poverty (and welfare generosity) the assumption that redistribution is best organised at the central level is rather dominant. Fundamental constraints on redistribution by lower level governments would -according to this line of reasoning- facilitate a 'race to the bottom'. This paper investigates the relationship between the generosity of social assistance benefits and several dimensions of decentralisation (the administration, decision-making and funding of social assistance schemes) at two levels of government (the substate and the local level) in 21 OECD countries by means of a fuzzy set analysis. The results indicate that social asssitance benefits are more adequate in countries where the decision-making, funding and administration of social assistance schemes is controlled by the central government and in countries where central or substate governments set the basic social assistance rates and housing benefits while sharing funding liabilities with the local government level. When Central and Eastern European countries opt for decentralisation as an instrument of poverty alleviation – through a better targeting of benefits -, prudence is called for the fact that there might be a trade-off between the transfer of competencies to lowel levels of government and the generosity of welfare programmes.decentralization; devolution; social policy; social assistance; Europe; OECD; Fuzzy Set; social welfare; race to the bottom; federalism

    Problem centred city-hinterland management - a scientific and policy approach

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    According to models of urban development the relations between city cores and its hinterlands are defined by strong inter-linkages and interdependencies. Some examples for those are: - Procurement of reserve areas - Exchange of energy and mass-flows - Sharing of logistical and deposit functions. Co-operations are used to foster these inter-linkages and the institutional framework with its relevant actors (organisations, associations) embedded in both spatial areas are used to determine this frame. In former works we have identified two layers to analyse these co-operations (i.e. micro and macro level). The micro level can be defined also as the personal level where personal contacts and interactions in form of communication patterns and information flows determine the problem solution capacity, the relationship between the actors/players and the success and failure of a co-operation. The macro level can be defined as the overall framework conditions or the system related conditions. These conditions influence city-hinterland relations directly and are often the reason for failed co-operation efforts. Therefore it is necessary to check these conditions first. This paper will deal with the possible design and management of city-hinterland relations which may overcome conflicts and weaknesses. Our approach will not only be based upon empirical evidence from the Vienna region but also be embedded in an interdisciplinary scientific frame. We will therefore try to combine regional science and management science as well as behavioural science in this design. The key hypothesis will be that efficient and effective city-hinterland management will only be possible if centred on problems at hand rather than institutional routines. Co-operations in this context should help to strengthen this orientation. The empirical background of our paper will be drawn from the findings of a research project funded within the focal research programme "Kulturlandschaftsforschung" of the Austrian Federal Ministry of Science. Within this research project four city-hinterland municipalities within the metropolitan area of Vienna have been thoroughly analysed. This contribution will provide the basic information to derive the mentioned theoretical framework.

    Do Parties Matter for Fiscal Policy Choices? A Regression-Discontinuity Approach

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    This paper presents a method for measuring the causal effect of party control on fiscal policy outcomes. The source of identifying information comes from an institutional feature of the election system, namely that party control changes discontinuously at 50 percent of the vote share, i.e., a party that receives more than 50 percent of the votes will be in office. The approach is applied to a very large panel data set from Swedish local governments, which offers a number of attractive features. The results show that there is large and significant party effect: on average, left-wing parties spend and tax 2.5 percent more than right-wing governments. The party effect constitutes 1 percent of average municipality income, clearly a sizeable effect.political parties; party control; regression-discontinuity design

    "Organic District": identification methodology and agricultural policy objectives

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    Italy, unlike other countries, has included the territorial dimension in the recent interventions and regulations of organic agriculture, introducing explicitly the concept of “organic district”. It is defined as a local productive system with a high agricultural vocation where organic production and processing practices are predominant. The main object of this new subject is to promote the diffusion of organic agriculture focusing on the productive and environmental territorial characteristic. In this poster, after a general definition of the organic districts, as they are introduced in the Italian regulations, a method for their identification in a region is proposed. In the final part, some considerations about the role of the organic district within the general framework of agro-environmental policies are developed.organic district, agro-environmental policies, organic agriculture, Agricultural and Food Policy, Environmental Economics and Policy,
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