Francisco Saez de Adana

Localization Approach Based on Ray-Tracing Including the Effect of Human Shadowing

This work presents an accurate and realistic positioning approach for indoor environments based on fingerprinting and raytracing techniques. Fading caused by multipath seriously degrades the performance of communication systems operating inside buildings. For this reason, the proposed localization method considers multipath effects due to reflections and diffraction from walls, roof and floor. However, fading in indoor environments can also be caused by the movement of people or the presence of furniture. Because people are the primary absorption agents in indoor channels, their influence on the radio propagation channel must be considered. The proposed localization method takes into account the effects of human body shadowing to provide a realistic estimation of the mobile station position. Numerical calculations in real indoor scenarios show reasonable results.

A Comparative Study of Localization Methods in Indoor Environments

A comparative study, based on three different measurements (direction of ray arrival, time difference of arrival and received signal strength), to compute the unknown position of mobile stations in indoor environments is presented in this paper. The comparison is carried out considering the results of analyses in a real building in Madrid. To overcome the problems that arise in indoor areas due to the presence of non line of sight conditions, the fingerprinting technique is applied in each of the cases. Data for computations are provided by a simulation tool based on the uniform theory of diffraction and ray-tracing techniques. This information is stored in the fingerprinting database and contains information related to every mobile station, every reference node and every access point located inside the environment under analysis. Experimental results compare the mean error when localizing several mobile stations by using the three different approaches. The goal is to obtain high precision in the localization by means of alternative methods to the received signal strength classical measurement. These techniques will be useful in critical environments where high operational security requirement are demanded.

Ray-tracing application to mobile localization in multipath indoor environments

This work presents a new indoor localization method based on the fingerprinting technique. A Ray-Tracing model is used to provide information about the multipath effects. The fingerprinting technique uses the direction of arrival (DOA) and the received signal strength (RSS) of the received rays. The location estimation is calculated while taking into account the Euclidian distance between the DOA and the RSS from each unknown position and the information of the fingerprints. To prove the goodness of the algorithm, a scene of a real building was analyzed. Numerical calculations were performed to show the mean error and the variance of the estimated error in the location process.

APPLICATION OF THE PARTICLE SWARM OPTIMIZATION TO THE COMPUTATION OF THE GO/UTD REFLECTION POINTS OVER NURBS SURFACES

A new method to flnd the Geometrical Optics/Uniform Theory of Difiraction re∞ection points over Non Uniform Rational B- Splines surfaces is presented. The approach is based on the Particle Swarm Optimization (PSO) technique, and the cost function used to flnd the re∞ection points is based on Snells law. The technique can be used as an alternative to classic minimization techniques in cases where convergence problems arise.

Attachment and grief: the case of the death of Raven Sherman

This paper applies the theory of attachment to explain the reaction of readers to one of the most important deaths in comic strips: the death of Raven Sherman in Terry and the Pirates by Milton Can...ABSTRACT This paper applies the theory of attachment to explain the reaction of readers to one of the most important deaths in comic strips: the death of Raven Sherman in Terry and the Pirates by Milton Caniff. The readers’ attachment to the character is shown in their letters preserved in the author’s collection at the Billy Ireland Cartoon Library & Museum. This attachment produces grief when an important character, such as Raven Sherman, dies. The collective grief involves the four phases presented by John Bowlby in relation to the loss of a close person, demonstrating readers’ attachment to the character in the strip. The paper also discusses how the possibility of grieving for a comic character has been lost because, among other reasons, death has lost significance in superhero comics.

Web-based application to obtain the propagation in outdoor environments importing data from OpenStreetMaps

The implementation of a web-based application to obtain the propagation in outdoor environments is presented in this paper. The tool provides the results of an empirical formulation in a friendly user interface. The main advantage of the proposed system is that the data of the environment are obtained from OpenStreetMaps allowing the calculation at any part of the world with an easy accessibility to the required data. Moreover, the formulation is applicable to rural and urban environments. The web application has been implemented using HTML5 and CSS3. The open source JavaScript library Leaflet has been used to include interactive maps.

Identification of clusters in the fingerprinting method using power measurements

Detection method plays important role in applications of high frequencies techniques for locations systems. One of the most popular techniques is the fingerprinting that operates the relationship between signals. It is considered that in each point in the building has a unique fingerprint or received power by the access points. In this work it was made measurements into an office scenario and it was used cluster identification method to define the fingerprints. Two clustering algorithms, k-means and rek-means was implemented in order to compare both methods.

Ray Tracing Acceleration Techniques

A short review of ray-tracing acceleration techniques for visualization and electromagnetic applications is presented. Techniques for different scenarios and types of illuminating waves are considered, distinguishing mainly between coherent and incoherent waves. Keywords: ray tracing; shooting and bouncing of rays; image method; bounding boxes; kd-tree algorithm; binary space partitioning; volumetric space partitioning; angular Z-buffer