Andres Navarro

Mobility, turnover and storage of pollutants in soils, sediments and waters : achievements and results of the EU project AquaTerra. A review

AquaTerra is one of the first environmental projects within the 6th Framework program by the European Commission. It began in June 2004 with a multidisciplinary team of 45 partner organizations from 13 EU countries, Switzerland, Serbia, Romania and Montenegro. Results from sampling and modeling in 4 large river basins (Ebro, Danube, Elbe and Meuse) and one catchment of the Brévilles Spring in France led to new evaluations of diffuse and hotspot input of persistent organic and metal pollutants including dynamics of pesticides and polycyclic aromatic hydrocarbons, as well as metal turnover and accumulation. While degradation of selected organic compounds could be demonstrated under controlled conditions in the laboratory, turnover of most persistent pollutants in the field seems to range from decades to centuries. First investigations of long-term cumulative and degradation effects, particularly in the context of climate change, have shown that it is also necessary to consider the predictions of more than one climate model when trying to assess future impacts. This is largely controlled by uncertainties in climate model responses. It is becoming evident, however, that changes to the climate will have important impacts on the diffusion and degradation of pollutants in space and time that are just at the start of their exploration.

DVB Coverage Prediction Using Game Engine Based Ray-Tracing Techniques

This paper presents the results of an evaluation of a propagation model based on ray-tracing techniques using a game engine and Graphics Processing Unit (GPU) in outdoor scenarios, as a gap-filler for a Digital Video Broadcasting Handheld (DVB-H) service. This model involves complete identification of the parameters of wave propagation, multipath components between the transmitter and the receiver as attenuation, time delay of arrival (TDA), full polarimetric transmission matrix, direction of arrival DoA and the direction of departure DoD. In the paper, we present the results of the simulation and compare them with measurements, obtaining a satisfactory fit.

Applicability of Game Engine for Ray Tracing Techniques in a Complex Urban Environment

This work presents results for a new method of ray tracing in urban environments using game engine and graphic processing unit (GPU). First advantage obtained with this method is the simplicity for 3D modeling from raster digital elevation model (DEM). Second advantage is the ability to precisely obtain ray parameters and the multiple paths interacting between transmitter and receiver in urban environment for high and low base station. A third advantage is the reduction in computing time by using the GPU capacity. In this paper, we show simulation results and compare them with measurements, obtaining a good fit.

Vertical Handoff Algorithms — A new approach for performance evaluation

A myriad of Vertical Handoff Algorithms (VHA) have been proposed by researchers and networks practitioners. These algorithms allow mobile terminals (MT) to maintain the network connection when they switch from one wireless network to another one. Given the amount of proposed VHA and the need for an objective assessment of these solutions different evaluation methodologies have been proposed, becoming the problem of evaluation of VHA in an interesting challenge. However, there is no consensus on how to evaluate performance of VHA. In this paper, we address this issue by proposing a new approach for evaluating the VHA, which is based on multi-criteria evaluation and criticality analysis — a specific concept taken from the operational reliability. The new approach allows evaluating VHA using measured values of some defined parameters, which can be obtained from simulating VHA on a network simulation tool (e. g. NCTUns, NS −2, OMNET++, among others) or generic software simulation tools (e.g. MATLAB). As a test of the new model, an evaluation of five VHA is presented.

Measurement-based ray-tracing models calibration in urban environments

This paper investigates the effect produced on the accuracy of the estimate of path loss in an outdoor environment in order to adjust the permittivity values for building wall, building roof and street floor by using a full 3D ray-tracing system. Due to the complexity of a real situation, estimation of path loss using the ray-tracing method is generally assumed one or three large classes of homogeneous materials to represent the building walls, building roofs and street floors in order have a viable model of the 3D environment. However, in a real case, an outdoor environment consists of many buildings and streets made of heterogeneous materials. We analyze the behavior of the statistical variation of standard deviation, correlation coefficient and the average error between the values of estimated and measured path loss data when considering various values of permittivity of these three classes. Finally we adjust the values of permittivity obtaining a reasonable improvement of ray tracing to estimate the path-loss.

A reliability assessment software using Kinect to complement the clinical evaluation of Parkinson's disease

Parkinsons disease is characterized by alterations in the gait pattern that may increase the risk of falls. Variations in the gait pattern cannot be objectively measured in clinical examination, so it is necessary to adapt devices to measure objectively, valid and replicable changes in gait patterns that are part of the evolution of the disease and / or pharmacotherapy. In an interdisciplinary effort, we developed the “e-Motion Capture System” software, which is able to calculate motor (cadence, stride and step length) and spatiotemporal (velocity and acceleration) parameters that affect quality of life in patients with Parkinsons disease. In this paper, we show results of the comparison between our e-Motion software and a benchmark reference, multiple-camera 3D motion capture system to track a gait pattern. This analysis was performed to compare the spatial locations of the ankles of a volunteer under indoor controlled conditions. Our results for the comparison between e-Motion and the 3D motion capture system show excellent agreement.

Game engines ray-tracing models for indoor channel modeling

This paper investigates the use of a full 3D ray-tracing system based on Game Engine for the prediction of channel parameters in indoor using frequencies lower than usual. We explore the modeling of indoor channel for Digital TV frequencies and analyze the behavior of material on such low frequencies and how the frequencies affect the constitutive parameters of materials in the scenario. Because of the environment used for experimentation, the number of rays is very high and the number of interactions is higher than usual. We show results of the ray tracing model compared with measurements of delay spread at 594MHz.

Adaptive planning of 3G/4G systems using Q-analysis or polyhedral dynamics

We present a method for Q-analysis in the initial planning process and dynamic adaptation for 3G/4G cellular systems that intends to balance the load in order to maximize the capacity and reduce the lost and dropped calls independent of the type of service. We support our proposal on dynamic simulations made with an our own developed tool for dynamic simulations of CDMA systems, and show the initial results that partially probe our proposed method.

Using 3D game engines and GPU for ray launching based channel modeling in indoor

This paper investigates the use of a full 3D ray-launching system based on Game Engine and GPU for the prediction of channel parameters in indoor. We explore the behavior of the materials and the possible influence of objects external to the room where measurements were performed. We explore the modeling of indoor channel for Digital TV frequencies and analyze the behavior of material on such low frequencies and how the frequencies affect the constitutive parameters of materials in the scenario. Because of the environment used for experimentation, the number of rays is very high and the number of interactions is higher than usual. We show results of the ray tracing model compared with measurements of delay spread at 594MHz in a meeting room.

Work in progress — Serious 3D game for mobile networks planning

Serious games is an emerging technology growing in importance for specialized training, taking advantage of 3D games and game engines in order to improve the realistic experience of users. The concept of a serious game combines the concept of computer games used for recreational purposes with specific goals like training specialized personnel and is part of the concept of blended learning. The idea of a serious game for radio planning requires some level of abstraction and a combination between visual designers and engineers in order to maintain accurate concepts about radio and a good “feeling” from the gamer or user side. In this paper we expose the development of a serious game for Telecommunications planning training, which uses open source tools and real data from Digital Terrain Maps. We combine some innovative ideas about propagation models, 3D modeling of digital terrain, game engines and a traditional radio planning tool.