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Santos S.,NOVA Information Management School | Cabral P.,NOVA Information Management School | Zamyatin A.,Tomsk State University
International Journal of Agricultural and Environmental Information Systems | Year: 2015

In this study, land use and cover changes in continental Portugal are analyzed for years 1980,1995 and 2010 using samples of the Landyn research project. The modeling approach includes testing the hypothesis that land cover changes are generated by a frst-order Markov process. Results show that the changes in land use and cover are dependent of the previous moment in time, i. e., they follow a Markov process. Accordingly multi-decadal land cover projections of Landyn simplif ed land cover classes are legitimately presented and analyzed for continental Portugal and its regions for years 2020, 2030 and 2040. To make these results spatially explicit, a modelling approach which combines Markov chains with cellular automata is carried out using hypothetical scenarios. The quantitative and spatially explicit information provided by this study enables a better understanding oftendencies in land cover change and may be useful for territorial planning and management. Copyright © 2015, IGI Global. Source


Sarmento P.,NOVA Information Management School | Sarmento P.,Polytechnic Institute of Coimbra | Fonte C.C.,Polytechnic Institute of Coimbra | Fonte C.C.,University of Coimbra | And 3 more authors.
International Journal of Remote Sensing | Year: 2015

The accuracy assessment of land-cover maps requires reference databases which are intended to represent ground truth. However, these reference databases are usually obtained through photo-interpretation of aerial or very-high-resolution satellite images and therefore have uncertainty which will influence the results of the accuracy assessment. Previous efforts to account for this source of uncertainty have employed a linguistic scale to translate the degree of correspondence between the ground conditions and each land-cover class for each sample location. The linguistic scale is transformed into fuzzy intervals with this transformation based on a photo-interpreter’s hypothetical ideal perception of the land-cover areal coverage for a sample unit. The end result is a fuzzy accuracy assessment. The objectives of this article are to assess the degree to which the real response of photo-interpreters corresponds to the assumed ideal response and to evaluate the impact these differences have on the results of an accuracy assessment. To achieve this objective, we examine linguistic scales with five and seven values. Furthermore, we develop a method to transform these scales into interpreter-derived fuzzy intervals expressing the proportion of area of land cover for each sample unit. This transformation is accomplished using a control sample in which the area occupied by each land-cover class is assessed. The methodology is tested via a case study where a map with five land-cover classes is evaluated. The accuracy assessment is performed with both hypothetical ideal interpreter response and with the interpreter-derived fuzzy intervals. The results for the fuzzy accuracy measures produced from the different analyses show that there are considerable differences between the results obtained with the linguistic scale with five and seven values, and that the interpreter-derived seven-value linguistic scale provides results very similar to those obtained with the ideal interpreter response. © 2015 Taylor & Francis. Source


Martins R.,NOVA Information Management School | Oliveira T.,NOVA Information Management School | Thomas M.A.,Virginia Commonwealth University
Journal of Organizational Computing and Electronic Commerce | Year: 2015

The information systems outsourcing (ISO) field continues to grow, as organizations consistently seek improvements in IT activities. The global scope of outsourcing participation and growth leads to gaps of knowledge related to the contextual factors that influence ISO adoption. Using the technology-organization-environment (TOE) framework, this study identifies and contextualizes the determinants of ISO adoption. Data collected from 261 firms suggest that relative advantage, firm size, top management support, and competitive pressure are the main determinants of ISO. This study highlights the importance of assessing ISO using the TOE theoretical lens, and offers replication of prior results, the lack of which is a growing concern in social science research. © Taylor & Francis Group, LLC. Source

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