An increasing amount of freely available Geographic Information System (GIS) data on the Internet has stimulated recent research into Geographic Information Retrieval (GIR). Typically, GIR looks at the problem of retrieving GIS datasets on a theme by theme basis. However in practice, themes are generally not analysed in isolation. More often than not multiple themes are required to create a map for a particular analysis task. To do this using the current GIR techniques, each theme is retrieved one by one using traditional retrieval methods and manually added to the map. To automate map creation the traditional GIR paradigm of matching a query to a single theme type must be extended to include discovering relationships between different theme types.Bayesian Inference networks can and have recently been adapted to provide a theme to theme relevance ranking scheme which can be used to automate map creation [2]. The use of Bayesian inference for GIR relies on a manually created Bayesian network. The Bayesian network contains causal probability relationships between spatial themes. The next step in using Bayesian Inference for GIR is to develop algorithms to automatically create a Bayesian network from historical data. This paper discusses a process to utilize conventional Bayesian learning algorithms in GIR. In addition, it proposes three spatial learning Bayesian network algorithms that incorporate spatial relationships between themes into the learning process. The resulting Bayesian networks were loaded into an inference engine that was used to retrieve all relevant themes given a test set of user queries. The performance of the spatial Bayesian learning algorithms were evaluated and compared to performance of conventional non-spatial Bayesian learning algorithms. This contribution will increase the performance and efficiency of knowledge extraction from GIS by allowing users to focus on interpreting data, instead of focusing on finding which data is relevant to their analysis.
Many substantial geographic information systems (GIS) have been designed for use by expert users. As a result, nonexpert users often find them difficult to use. This paper presents a framework to facilitate the use of such GIS by non-expert users. The framework achieves this by allowing the creation of vague visual queries which use data abstraction and relevance feedback to obtain a final result. The data abstraction model is dynamically updated to improve future query performance.
Where airports were once the sole responsibility of their governments, liberalisation of economies has seen administrative interests in airport spaces divested increasingly towards market led authority. Extant literature suggests that actions in decision spaces can be described under broad idealised forms of governance. However in looking at a sample of 18 different airports it is apparent that these classic models are insufficient to appreciate the contextual complexity of each case. Issues of institutional arrangements, privatisation, and management focus are reviewed against existing governance modes to produce a model for informing privatisation decisions, based on the contextual needs of the individual airport and region. Expanding governance modes to include emergent airport arrangements both contribute to the existing literature, and provides a framework to assist policy makers and those charged with the operation of airports to design effective governance models. In progressing this framework, contributions are made to government decision makers for the development of new, or review of existing strategies for privatisation, while the private sector can identify the intent and expectations of privatisation initiatives to make better informed decisions.
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