EEG signal analysis via a cleaning procedure based on multivariate empirical mode decomposition

Artifacts are present in most of the electroencephalography (EEG) recordings, making it difficult to interpret or analyze the data. In this paper a cleaning procedure based on a multivariate extension of empirical mode decomposition is used to improve the quality of the data. This is achieved by applying the cleaning method to raw EEG data. Then, a synchrony measure is applied on the raw and the clean data in order to compare the improvement of the classification rate. Two classifiers are used, linear discriminant analysis and neural networks. For both cases, the classification rate is improved about 20%.

The effect of pesticides and alien invesive species on soil biota and litter decomposition rates in a Mediterrean-climate ecosystem of Western Australia

Ecosystems are complex systems and changing one of their components can alter their whole functioning. Decomposition and biodiversity are two factors that play a role in this stability, and it is vital to study how these two factors are interrelated and how other factors, whether of human origin or not, can affect them. This study has tested different hypotheses regarding the effects of pesticides and invasive species on the biodiversity of the soil fauna and litter decomposition rate. Decomposition was measured using the litterbags technique. Our results indicate that pesticides had a negative effect on decomposition whereas invasive species increased decomposition rate. At the same time, the diversity of the soil biota was unaffected by either factor. These results allow us to better understand the response of important ecosystem functions to human‐induced alterations, in order to mitigate harmful effects or restore them wherever necessary.

Disentangling water usage in the European Union: A decomposition analysis

The Water Framework Directive (WFD) defines common objectives for water resources throughout the European Union (EU). Given this general approach to water preservation and water policy, the objective of this paper is to analyse whether common patterns of water consumption exist within Europe. In particular, our study uses two methods to reveal the reasons behind sectoral water use in all EU countries. The first method is based on an accounting indicator that calculates the water intensity of an economy as the sum of sectoral water intensities. The second method is a subsystem input‐output model that divides total water use into different income channels within the production system. The application uses data for the years 2005 and 2009 on water consumption in the production system of the 27 countries of the EU. From our analysis it emerges that EU countries are characterized by very different patterns of water consumption. In particular water consumption by the agriculture sector is extremely high in Central/Eastern Europe, relative to the rest of Europe. In most countries, the water used by the fuel, power and water sector is consumed to satisfy domestic final demand. However, our analysis shows that for some countries exports from this sector are an important driver of water consumption. Focusing on the agricultural sector, the decomposition analysis suggests that water usage in Mediterranean countries is mainly driven by final demand for, and exports of, agricultural products. In Central/Eastern Europe domestic final demand is the main driver of water consumption, but in this region the proportion of water use driven by demand for exports is increasing over time. Given these heterogeneous water consumption patterns, our analysis suggests that Mediterranean and Central/Eastern European countries should adopt specific water policies in order to achieve efficient levels of water consumption in the European Union. JEL codes: N5; C67 Keywords: Water use, Subsystem input–output model; Water intensity, European Union.

Resolução espacial de um modelo digital de elevação definida pela função wavelet

O objetivo deste trabalho foi definir a resolução espacial mais apropriada para representar a variabilidade da elevação, declividade, curvatura em perfil e índice de umidade topográfica de um terreno, por meio de avaliações com a transformada wavelet. Os dados utilizados no estudo têm sua origem em três transectos de 27 km, posicionados em áreas do Planalto, Rebordo do Planalto e Depressão Central na região central do Estado do Rio Grande do Sul. As variáveis - elevação, declividade, curvatura em perfil e índice de umidade topográfica - foram derivadas de um modelo digital de elevação Topodata com resolução de 30 m. A avaliação da resolução com a máxima variabilidade foi realizada pela aplicação da wavelet-mãe, denominada Morlet. Os resultados foram analisados a partir do isograma e do escalograma dos coeficientes wavelet e indicaram que sensores remotos com resolução espacial próxima a 32 e 40 m podem ser utilizados em pesquisas que considerem os atributos de terreno, como declividade, curvatura em perfil e índice de umidade topográfica, ou, ainda, fenômenos ambientais correlacionados a eles. No entanto, não foi possível estabelecer um valor conclusivo para a resolução espacial mais adequada para a variável elevação.

SAR Interferometric phase noise reduction using wavelet transform

The problem of synthetic aperture radar interferometric phase noise reduction is addressed. A new technique based on discrete wavelet transforms is presented. This technique guarantees high resolution phase estimation without using phase image segmentation. Areas containing only noise are hardly processed. Tests with synthetic and real interferograms are reported.

The continuous wavelet transform as a maximum entropy solution of the corresponding inverse problem

The continuous wavelet transform is obtained as a maximumentropy solution of the corresponding inverse problem. It is well knownthat although a signal can be reconstructed from its wavelet transform,the expansion is not unique due to the redundancy of continuous wavelets.Hence, the inverse problem has no unique solution. If we want to recognizeone solution as "optimal", then an appropriate decision criterion hasto be adopted. We show here that the continuous wavelet transform is an"optimal" solution in a maximum entropy sense.

On wideband deconvolution using wavelet transform

A discussion on the expression proposed in [1]–[3]for deconvolving the wideband density function is presented. Weprove here that such an expression reduces to be proportionalto the wideband correlation receiver output, or continuous wavelettransform of the received signal with respect to the transmittedone. Moreover, we show that the same result has been implicitlyassumed in [1], when the deconvolution equation is derived. Westress the fact that the analyzed approach is just the orthogonalprojection of the density function onto the image of the wavelettransform with respect to the transmitted signal. Consequently,the approach can be considered a good representation of thedensity function only under the prior knowledge that the densityfunction belongs to such a subspace. The choice of the transmittedsignal is thus crucial to this approach.

Decomposition of differences in PISA results in middle income countries

Programme for International Student Assessment

Decomposition of Ruppia cirrhosa (Petagna) Grande in the sediment of a coastal lagoon

The decomposition process of Ruppia cirrhosa was studied in a Mediterranean coastal lagoon in the Delta of the River Ebro (NE Spain). Leaves and shoots of Ruppia were enclosed in 1 mm-mesh and 100 pm-mesh litter bags to ascertain the effect of detritivores, macroinvertebrates, and bacteria and fungi, respectively. Changes in biomass and carbon, and, nitrogen and phosphorus concentrations in the detritus were studied at the sediment-water interface and in the sediment. Significant differences in biomass decay were observed between the two bag types. Significant differences in decomposition were observed between the two experimental conditions studied using 100 pm-mesh bags. These differences were not significant when using the 1 mm-mesh bags. The carbon content in the detritus remained constant during the decomposition process. The percentage of nitrogen increased progressively from an initial 2.4 % to 3 %. The percentage of phosphorus decreased rapidly during the first two days of decomposition from an initial 0.26 % to 0.17 %. This loss is greater in the sediment than in the water column or at the sediment-water interface. From these results we deduce that the activity of microorganisms seems to be more important in the sediment than in the water-sediment interface, and that grazing by macroinvertebrates has less importance in the sediment than in the water column.

Selecting Wavelet Filter for Compression of Spectra from Multispectral Images

The problem of selecting anappropriate wavelet filter is always present in signal compression based on thewavelet transform. In this report, we propose a method to select a wavelet filter from a predefined set of filters for the compression of spectra from a multispectral image. The wavelet filter selection is based on the Learning Vector Quantization (LVQ). In the training phase for the test images, the best wavelet filter for each spectrum has been found by a careful compression-decompression evaluation. Certain spectral features are used in characterizing the pixel spectra. The LVQ is used to form the best wavelet filter class for different types of spectra from multispectral images. When a new image is to be compressed, a set of spectra from that image is selected, the spectra are classified by the trained LVQand the filter associated to the largest class is selected for the compression of every spectrum from the multispectral image. The results show, that almost inevery case our method finds the most suitable wavelet filter from the pre-defined set for the compression.

Multispectral image compression using the wavelet transform

Multispectral images contain information from several spectral wavelengths and currently multispectral images are widely used in remote sensing and they are becoming more common in the field of computer vision and in industrial applications. Typically, one multispectral image in remote sensing may occupy hundreds of megabytes of disk space and several this kind of images may be received from a single measurement. This study considers the compression of multispectral images. The lossy compression is based on the wavelet transform and we compare the suitability of different waveletfilters for the compression. A method for selecting a wavelet filter for the compression and reconstruction of multispectral images is developed. The performance of the multidimensional wavelet transform based compression is compared to other compression methods like PCA, ICA, SPIHT, and DCT/JPEG. The quality of the compression and reconstruction is measured by quantitative measures like signal-to-noise ratio. In addition, we have developed a qualitative measure, which combines the information from the spatial and spectral dimensions of a multispectral image and which also accounts for the visual quality of the bands from the multispectral images.

Mobility Management in Packet Switched Mobile Networks

Nykyisin matkaviestinverkot ovat osa jokapäiväistä elämää. Merkittävimpiä eroja kiinteiden ja matkaviestinverkkojen välillä on käyttäjän liikkuvuus, joka voidaan määritellä mahdollisuudeksi soittaa ja vastaanottaa puheluita missä ja milloin tahansa. Työ selittää termin liikkuvuus ja määrittää ongelmat, jotka täytyy ratkaista liikkuvuuden aikaansaamiseksi sekä tavat, joilla nämä ongelmat on ratkaistu matkaviestinverkoissa. Työ luo yleiskatsauksen liikkuvuuden aikaansaamisessa käytettäviin menetelmiin, joita ovat haku, sijainnin päivitys, sijainnin seuranta ja kanavan vaihto. Työ keskittyy liikkuvuuteen kolmannen sukupolven matkaviestinverkkojen paketti-kytkentäisessä osassa, esimerkkinä liikkuvuuden hallinta UMTS:ssa (Universal Mobile Telecommunications System). Erot paketti- ja piirikytkentäisen osan välillä tuodaan esille ja selitetään. Jotta käyttäjät ja heidän päätteensä voisivat liikkua, tiedon täytyy kulkea verkon eri osien välillä. Merkinanto verkkoelementtien välillä ja liikkuvuuden mahdollistavien toimenpiteiden suoritus tehdään yhteyskäytännön avulla. Työ kuvaa yhteyskäytännöt, jotka ovat osallisena liikkuvuuden tarjontaan. Painopiste on GPRS:n liikkuvuuden-hallintayhteyskäytännössä, GMM:ssä. GMM protokollan prototyypin toteutus on esitetty työn käytännön osassa.

Wavelet Filter Parameterization for Compression of Spectral Images

Vaatimus kuvatiedon tiivistämisestä on tullut entistä ilmeisemmäksi viimeisen kymmenen vuoden aikana kuvatietoon perustuvien sovellutusten myötä. Nykyisin kiinnitetään erityistä huomiota spektrikuviin, joiden tallettaminen ja siirto vaativat runsaasti levytilaa ja kaistaa. Aallokemuunnos on osoittautunut hyväksi ratkaisuksi häviöllisessä tiedontiivistämisessä. Sen toteutus alikaistakoodauksessa perustuu aallokesuodattimiin ja ongelmana on sopivan aallokesuodattimen valinta erilaisille tiivistettäville kuville. Tässä työssä esitetään katsaus tiivistysmenetelmiin, jotka perustuvat aallokemuunnokseen. Ortogonaalisten suodattimien määritys parametrisoimalla on työn painopisteenä. Työssä todetaan myös kahden erilaisen lähestymistavan samanlaisuus algebrallisten yhtälöiden avulla. Kokeellinen osa sisältää joukon testejä, joilla perustellaan parametrisoinnin tarvetta. Erilaisille kuville tarvitaan erilaisia suodattimia sekä erilaiset tiivistyskertoimet saavutetaan eri suodattimilla. Lopuksi toteutetaan spektrikuvien tiivistys aallokemuunnoksen avulla.

Managing Packet Data (Sessions) in 3G Mobile Networks

Tällä hetkellä kolmannen sukupolven matkapuhelinjärjestelmät ovat siirtyneet kaupalliseen vaiheeseen. Universal Mobile Telecommunication System (UMTS) on eräs kolmannen sukupolven matkapuhelinjärjestelmä, jota tullaan käyttämään Euroopassa. Diplomityön päämääränä on tutkia, kuinka pakettivälitteistä tiedonsiirtoa hallitaan UMTS - verkoissa. Diplomityö antaa yleiskuvan toisen sukupolven matkapuhelinjärjestelmien datapalveluiden kehityksestä kolmannen sukupolven nopeisiin matkapuhelinjärjestelmiin. Pakettivälitteisen verkon verkkoarkkitehtuuri on esitetty sekä sen, diplomityön kannalta, tärkeimpien osien toiminnallisuus on selvitetty. Myös pakettipohjaisten datayhteyksien eli istuntojen muodostaminen ja vapauttaminen sekä aktiivisen yhteyden ominaisuuksien muokkaaminen on esitetty tässä diplomityössä. Yhteydenhallintaprotokolla, Session Management (SM), on yksi protokolla, joka osallistuu pakettidatayhteyden hallintaan. SM -protokolla on käsitelty työssä yksityiskohtaisesti. SM -protokollan SDL toteutus on esitetty diplomityön käytännönosassa