Abstract
This paper addresses the detection and classification of low amplitude signals within the QRS complex of the signal-averaged electrocardiogram. Linear and bilinear Kalman filter models are fitted using the subspace system identification family of algorithms. If the residuals from the models are a white noise process, then anything that cannot be modeled with the state-space models will show up in the residuals as low amplitude signal + noise. Diagnostic tests and analysis on the residuals will then lead to detection and classification of abnormalities in the intra-QRS complex. The end result is a diagnostic tool to aid the physician. © 2012 IFAC.

Abstract
In this paper the Wiener-Hammerstein Benchmark is identified as a bilinear discrete system. The bilinear approximation relies on both facts that the Wiener-Hammerstein system can be described by a Volterra series which can be approximated by bilinear systems. The identification is performed with an iterative bilinear subspace identification algorithm previously proposed by the authors. In order to increase accuracy, polynomial static nonlinearities were added to the bilinear model input. These Hammerstein type bilinear models are then identified using the same iterative subspace identification algorithm.

Abstract
The measurement of shear wave velocity (Vs) is an established approach in contributing to earthquake site response. Currently, in terms of sensors, horizontal geophones have been added as an option to the more common vertical geophones and thus being able to measure Love waves. In terms of processing the most recent development has been the possibility of joint inversion of data sets of different types (Rayleigh+Love, Rayleigh+HVSR, Rayleigh+Refraction). Since some of most important earthquake site response measurements have to be performed in urban environments this can pose a problem to the in situ measurements due to the lower signal to noise ratio. Thus we aim to show a case study of results of dispersive wave tests, made in the urban environment of the city Porto in Northern Portugal, with the objective of contributing towards a microzoning GIS map that we are currently engaged in improving. Porto is set in a crystalline environment with a rock mass that is variably weathered thus our test results will be compared with the geotechnical map of Porto.

Abstract
The assessment of contaminant dispersion in Controlled Dumps (CD) of Municipal Solid Waste (MSW) is possible through the combination of geophysical, geochemical and statistical methods. The methodology applied in this study will contribute to evaluate the environmental consequences of the Matosinhos CD (N Portugal), which is set in a granitic crystalline geological context with a permeability controlled by differential weathering which, in turn, is associated with fracturing. The statistical methods that we will describe are usually used in geochemical anomaly determination and were adapted to be used with resistivity data obtained from twenty-two 2D profiles performed around the CD. The data set was inverted and the results were processed and visualized by a 3D software application that we are currently developing. Groundwater samples were also collected in piezometers, upstream and downstream of the CD, with the aim of directly confirming the presence of contaminants indirectly detected by the geophysical and geostatistical methods described before. The combination of these different approaches allows, in our opinion, an improved approach towards the detection and delineation of contaminant plumes from these deposits.

Abstract
In recent years some authors have given a certain amount of attention to towed seismic reflection acquisition systems. Based on some of these works we sought to design and test a system making use of currently available geophones instead of specifically designed sensors as employed in some previous works. Thus, bearing in mind that the geophone's characteristics are achieved in the conditions that they are originally designed to be employed in, i.e., coupled with a spike driven into the ground, we devoted our attention to some of the variables involved in the geophone's performance, namely the total weight, the effect of a spikeless geophone and the surfaces on which the geophone is placed. Previously, we had experimentally verified some variations in the signal response due to coupling geophones in different surface materials, such as hard soil, asphalt and concrete pavement and we noticed that these surface materials were in fact an important factor in the overall response. Hence, these materials, or as we also called them coupling agents, could be employed as a base material in the construction of a mobile seismic acquisition device composed of blocks of a certain size, on which the geophone would be then inserted and thus making it into a spikeless surface towable system. Therefore, various materials were tested in order to select one that could maintain a similar fidelity to that of the spike coupled geophone and thus contribute towards building a more time efficient and towable geophone and block system. Pinging tests revealed variations in the coupling frequency and damping characteristics of each coupling agent and from all of these tested materials one was selected for field comparative tests with the normally planted geophones with spike coupling. Finally a seismic reflection profile was acquired simultaneously with both systems, i.e., spike coupling versus cement block coupled geophones.

Abstract
Geophysical data represent subsoil structure in a specific area and can be used to extract subsoil information for various purposes. In this work we used this data type to detect anomalies/contamination in the subsoil. Our case study was based on data acquired around a landfill and the main objective is identifying contaminated areas as a result of leakage in landfill. This involves the application of statistical methods to detect anomalous values taking into account the whole data set, subdividing it in sublevels in relation to the surface, instead of using a single threshold (as usual). This work combines in the same software package the anomaly statistical analysis and several 3D representations of the results to validate and also helps understanding the final results of the analysis. Given that the original data used in the analysis, resistivity sections, is normally very sparse, a kriging geostatistical process was used to interpolate data in order to provide a volumetric representation of the subsoil in the area, providing a continuous spatial visualization. © 2012 IEEE.