Rubén Martínez

Weighted Voronoi Diagrams for Optimal Location of Goods and Services in Planar Maps

Location of industries or services is a classical problem with an overlapping of techniques involving a geographic support, a quantitative evaluation of supply and demand components, and communication networks. Traditional Cost-Benefit Analysis are focused towards maximization of economic and social benefits in terms of distance maps, minimization transport costs and desirability of goods and services. Economic, population and infrastructures models are variable along time, and consequently, sites used for their representation must be adequately weighted according to different criteria. The aggregation of different criteria in a unique objective function (depending on adjustable parameters) allows to identify a unique solution for the problem in terms of weighted distance maps linked to the objective function. Thus, Weighted Voronoi Diagrams (WVD) provide the most adequate framework for computing and representing the optimal localization linked to a unique global function. This paper considers the interaction between Weighted Voronoi Diagrams and Multicriteria Analysis in Facility Location Problem. First, we introduce a weighted Voronoi diagram based on the places to avoid filter the points of the scenario from infinite to a finite number. Then, Multicriteria Analysis chooses one point of the resulting set from a function that accumulates a list of given criteria. As a result of the process we get the ideal position of the new facility we want to locate in. The solution can afford both private and public facilities, desirable or undesirable as well with three levels of application relative to urban, metropolitan and regional areas.

Mobile Voronoi Diagrams for Traffic Monitoring under Bad Visibility Conditions

A semiautomatic management of traffic scenes displays a large diversity of mobile data arising from usual Computer Vision techniques. The mobile nature of inputs requires the combination of different techniques for filtering, tracking, and clustering features along a video sequence. These problems are considerably harder in presence of low visibility conditions arising from rain, fog or dazzling conditions. It is necessary a robust coarse-to-fine approach for supporting early alert in presence of conflict or dangerous situation at road intersections. Currently, there is no a general solution developed for low visibility conditions, and what there is, has been developed following particular strategies involving a specific combination of filters for extracting and analyzing the situation. Under low visibility conditions, mobile features are clustered as blobs with similar motion patterns and labelled in terms of a mobile Voronoi site which represents the centroid of a coloured region with similar kinematic pattern. For a fixed camera, and in absence of information about relative velocities of vehicles, kinematic involves the relative variation of colour and shape. With low visibility conditions and for real-time response, it is not necessary to work with a large palette of colours, and a reduction of bits per pixel is performed in the preprocessing stage. We illustrate our results with some scenes where reflections in water (rainy weather) or discontinuities linked to fog, can produce hallucinations for which our approach provides a robust kinematic method justifying the application of mobile Voronoi diagrams for mobile blobs as unifying principle.

An optimal property of the “(r,k ) class estimators”

The purpose of this work is to display optimal conditions, in terms of the Mean Square Error criterion of the (r,k) class estimators. This will be done with respect to the ordinary ridge repression, principal components and ordinary least squares estimate.

A software platform for eLearning of interventions in Cultural Heritage environments

We have developed a software tool for Learning of Conservation and Rehabilitation Tasks in AEC [Architecture, Engineering, Construction] environments. It is based on different multimedia contents [text, image, video, laser scan] which are georeferenced to a representation of an outdoor scene. Three-dimensional modelling is compatible with any kind of devices for photogrammetric surveying, including images and laser-based information. It intends to become an educational and corporative learning platform (e-Learning and e-Working), which will enable to instructors an effective design of online courses and an efficient management of learning techniques and collaboration activities on the web. Our contribution is focused towards the design and development of collaborative working environments, where experts with different expertise can share their knowledge in a common framework. This tool has been applied for planning intervention strategies, products and methodologies focused towards surveying, planning and executing conservation policies in architectural elements of the Spanish Cultural Heritage with a special regard to Accessibility issues.