960 resultados para filter


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BACKGROUND: Autologous blood transfusion (ABT) efficiently increases sport performance and is the most challenging doping method to detect. Current methods for detecting this practice center on the plasticizer di(2-ethlyhexyl) phthalate (DEHP), which enters the stored blood from blood bags. Quantification of this plasticizer and its metabolites in urine can detect the transfusion of autologous blood stored in these bags. However, DEHP-free blood bags are available on the market, including n-butyryl-tri-(n-hexyl)-citrate (BTHC) blood bags. Athletes may shift to using such bags to avoid the detection of urinary DEHP metabolites. STUDY DESIGN AND METHODS: A clinical randomized double-blinded two-phase study was conducted of healthy male volunteers who underwent ABT using DEHP-containing or BTHC blood bags. All subjects received a saline injection for the control phase and a blood donation followed by ABT 36 days later. Kinetic excretion of five urinary DEHP metabolites was quantified with liquid chromatography coupled with tandem mass spectrometry. RESULTS: Surprisingly, considerable levels of urinary DEHP metabolites were observed up to 1 day after blood transfusion with BTHC blood bags. The long-term metabolites mono-(2-ethyl-5-carboxypentyl) phthalate and mono-(2-carboxymethylhexyl) phthalate were the most sensitive biomarkers to detect ABT with BTHC blood bags. Levels of DEHP were high in BTHC bags (6.6%), the tubing in the transfusion kit (25.2%), and the white blood cell filter (22.3%). CONCLUSIONS: The BTHC bag contained DEHP, despite being labeled DEHP-free. Urinary DEHP metabolite measurement is a cost-effective way to detect ABT in the antidoping field even when BTHC bags are used for blood storage.

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Abstract Objective: Derive filtered tungsten X-ray spectra used in digital mammography systems by means of Monte Carlo simulations. Materials and Methods: Filtered spectra for rhodium filter were obtained for tube potentials between 26 and 32 kV. The half-value layer (HVL) of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F & MAM Detector Platinum and 8201023-C Xi Base unit Platinum Plus w mAs in a Hologic Selenia Dimensions system using a direct radiography mode. Results: Calculated HVL values showed good agreement as compared with those obtained experimentally. The greatest relative difference between the Monte Carlo calculated HVL values and experimental HVL values was 4%. Conclusion: The results show that the filtered tungsten anode X-ray spectra and the EGSnrc Monte Carlo code can be used for mean glandular dose determination in mammography.

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The Extended Kalman Filter (EKF) and four dimensional assimilation variational method (4D-VAR) are both advanced data assimilation methods. The EKF is impractical in large scale problems and 4D-VAR needs much effort in building the adjoint model. In this work we have formulated a data assimilation method that will tackle the above difficulties. The method will be later called the Variational Ensemble Kalman Filter (VEnKF). The method has been tested with the Lorenz95 model. Data has been simulated from the solution of the Lorenz95 equation with normally distributed noise. Two experiments have been conducted, first with full observations and the other one with partial observations. In each experiment we assimilate data with three-hour and six-hour time windows. Different ensemble sizes have been tested to examine the method. There is no strong difference between the results shown by the two time windows in either experiment. Experiment I gave similar results for all ensemble sizes tested while in experiment II, higher ensembles produce better results. In experiment I, a small ensemble size was enough to produce nice results while in experiment II the size had to be larger. Computational speed is not as good as we would want. The use of the Limited memory BFGS method instead of the current BFGS method might improve this. The method has proven succesful. Even if, it is unable to match the quality of analyses of EKF, it attains significant skill in forecasts ensuing from the analysis it has produced. It has two advantages over EKF; VEnKF does not require an adjoint model and it can be easily parallelized.

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This paper presents a novel technique to align partial 3D reconstructions of the seabed acquired by a stereo camera mounted on an autonomous underwater vehicle. Vehicle localization and seabed mapping is performed simultaneously by means of an Extended Kalman Filter. Passive landmarks are detected on the images and characterized considering 2D and 3D features. Landmarks are re-observed while the robot is navigating and data association becomes easier but robust. Once the survey is completed, vehicle trajectory is smoothed by a Rauch-Tung-Striebel filter obtaining an even better alignment of the 3D views and yet a large-scale acquisition of the seabed

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A visual SLAM system has been implemented and optimised for real-time deployment on an AUV equipped with calibrated stereo cameras. The system incorporates a novel approach to landmark description in which landmarks are local sub maps that consist of a cloud of 3D points and their associated SIFT/SURF descriptors. Landmarks are also sparsely distributed which simplifies and accelerates data association and map updates. In addition to landmark-based localisation the system utilises visual odometry to estimate the pose of the vehicle in 6 degrees of freedom by identifying temporal matches between consecutive local sub maps and computing the motion. Both the extended Kalman filter and unscented Kalman filter have been considered for filtering the observations. The output of the filter is also smoothed using the Rauch-Tung-Striebel (RTS) method to obtain a better alignment of the sequence of local sub maps and to deliver a large-scale 3D acquisition of the surveyed area. Synthetic experiments have been performed using a simulation environment in which ray tracing is used to generate synthetic images for the stereo system

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El càncer de mama és una de les causes de més mortalitat entreles dones dels països desenvolupats. És tractat d'una maneramés eficient quan es fa una detecció precoç, on les tècniques d'imatge són molt importants. Una de les tècniques d'imatge més utilitzades després dels raigs-X són els ultrasons. A l'hora de fer un processat d'imatges d'ultrasò, els experts en aquest camp es troben amb una sèrie de limitacions en el moment d'utilitzar uns filtrats per les imatges, quan es fa ús de determinades eines. Una d'aquestes limitacions consisteix en la falta d'interactivitat que aquestes ens ofereixen. Per tal de solventar aquestes limitacions, s'ha desenvolupat una eina interactiva que permet explorar el mapa de paràmetres visualitzant el resultat del filtrat en temps real, d'una manera dinàmica i intuïtiva. Aquesta eina s'ha desenvolupat dins l'entorn de visualització d'imatge mèdica MeVisLab. El MeVisLab és un entorn molt potent i modular pel desenvolupament d'algorismes de processat d'imatges, visualització i mètodes d'interacció, especialment enfocats a la imatge mèdica. A més del processament bàsic d'imatges i de mòduls de visualització, inclou algorismes avançats de segmentació, registre i moltes análisis morfològiques i funcionals de les imatges.S'ha dut a terme un experiment amb quatre experts que, utilitzantl'eina desenvolupada, han escollit els paràmetres que creien adientsper al filtrat d'una sèrie d'imatges d'ultrasò. En aquest experiments'han utilitzat uns filtres que l'entorn MeVisLab ja té implementats:el Bilateral Filter, l'Anisotropic Difusion i una combinació d'un filtrede Mediana i un de Mitjana.Amb l'experiment realitzat, s'ha fet un estudi dels paràmetres capturats i s'han proposat una sèrie d'estimadors que seran favorables en la majoria dels casos per dur a terme el preprocessat d'imatges d'ultrasò

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Simultaneous localization and mapping(SLAM) is a very important problem in mobile robotics. Many solutions have been proposed by different scientists during the last two decades, nevertheless few studies have considered the use of multiple sensors simultane¬ously. The solution is on combining several data sources with the aid of an Extended Kalman Filter (EKF). Two approaches are proposed. The first one is to use the ordinary EKF SLAM algorithm for each data source separately in parallel and then at the end of each step, fuse the results into one solution. Another proposed approach is the use of multiple data sources simultaneously in a single filter. The comparison of the computational com¬plexity of the two methods is also presented. The first method is almost four times faster than the second one.

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Teräksen raaka-ainekustannusten jyrkkä nousu pakottaa prosessiteollisuuden etsimään vaihtoehtoisia rakennemateriaaleja, joiden ominaisuudet ovat vähintään terästä vastaavia. Prosessiteollisuudessa joudutaan käyttämään runsaasti kemikaaleja kestäviä laitteita, jolloin rakennemateriaaliksi sopiva on haponkestävä teräs. Laitteiden kokojen kasvusta seuraa niiden kokonaispainojen kasvu aiheuttaen haasteita niitä kantaville perustuksille. Komposiitti on yksi varteenotettava vaihtoehto haponkestävän teräksen korvaajaksi, sillä komposiitin ominaisuus/painosuhde on terästä parempi. Diplomityön tavoitteena on ollut selvittää Washers & Filters – tuoteperheeseen kuuluvien laitteiden, DD-pesurin (Drum Displacer) ja GF- suotimen (GasFree Filter), rakenteista löytyvien osien mahdollisuutta korvata komposiitilla. Työn pohjaksi on käsitelty komposiittien ominaisuuksia, tyyppejä ja valmistusmenetelmiä sekä perehdytty sellupesureiden toimintaprosessiin. Tältä pohjalta löytyi valintakriteerien avulla rakenteita, joita olisi mahdollista korvata komposiitilla.

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La localización en ambientes de interiores basada en dispositivos modernos de uso masivo, como los dispositivos móviles, es un área actual de investigación y desarrollo que ha empezado a generar productos para diferentes aplicaciones. Sin embargo, la estimación del error en estas mediciones, sus fuentes y la forma como se propaga, que evita tener mayor exactitud en la localización, aún presenta un área pendiente de estudio. Esta investigación toma una de las técnicas comunes de estudio de localización de dispositivos por redes inalámbricas WiFi para estudiar los diferentes errores que ella conlleva, sus fuentes y su propagación. Este trabajo también propone un nuevo enfoque y nueva metodología, que permite reducir el error en la localización de dispositivos WiFi, con base a la clasificación de las redes inalámbricas presentes en un escaneo, la identificación de muestras y datos fortuitos, la estabilización de muestreos de potencias de redes WiFi, y la implementación de un filtro de Kalman, para la predicción de medidas estables de estas potencias.

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Työssä käsitellään suodinkakkujen kuivapitoisuuksien muuttumista, kun kuivauksessa käytetään paineilman sijasta kylläistä höyryä.

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Instrumental data always present some noise. The analytical data information and instrumental noise generally has different frequencies. Thus is possible to remove the noise using a digital filter based on Fourier transform and inverse Fourier transform. This procedure enhance the signal/noise ratio and consecutively increase the detection limits on instrumental analysis. The basic principle of Fourier transform filter with modifications implemented to improve its performance is presented. A numerical example, as well as a real voltammetric example are showed to demonstrate the Fourier transform filter implementation. The programs to perform the Fourier transform filter, in Matlab and Visual Basic languages, are included as appendices

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A comparative study of the Fourier (FT) and the wavelet transforms (WT) for instrumental signal denoising is presented. The basic principles of wavelet theory are described in a succinct and simplified manner. For illustration, FT and WT are used to filter UV-VIS and plasma emission spectra using MATLAB software for computation. Results show that FT and WT filters are comparable when the signal does not display sharp peaks (UV-VIS spectra), but the WT yields a better filtering when the filling factor of the signal is small (plasma spectra), since it causes low peak distortion.

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Tutkimuksen tavoitteena oli kehittää Larox Oyj:n alihankintaprojektien kustannuslaskentaa. Yrityksessä oli havaittu, että pitkäaikaishankkeiden kustan-nusten kertymistä pitää pystyä ennustamaan tarkemmin. Konstruktiivisen tutkimusotteen mukaisesti tutkimuksessa luotiin esiymmärrys kohdeyrityksen nykytilanteesta, perehdyttiin vaikuttavaan lainsäädäntöön ja aikaisempaan tutkimustietoon. Kuvaus nykytilanteesta luotiin kohdeyrityksen ja alihankkijan edustajien haastatteluiden avulla, tutustumalla yrityksen toimintaohjeisiin ja keräämällä tietoa projektien kustannusten kertymisestä. Kerätyn tiedon perusteella luotiin konstruktiot eli ratkaisuehdotukset toiminnan kehittämiseksi. Tutkimuksessa kehitettiin raportointimalli alihankintaprojektien edistymisen raportointiin. Mallin tavoitteena on yhtenäistää alihankkijoiden raportointikäy-täntöjä ja tuottaa sellaista tietoa, jota Larox tarvitsee tuottojen tunnistamista varten. Toinen konkreettinen ratkaisu on alihankintaprojektien kustannuskertymän ennustetyökalu, jonka avulla voidaan ennakoida hankkeen valmiusasteen kehitystä projektin aikana. Malli on rakennettu yhden konetyypin projektien ennustamiseen, mutta siitä voidaan helposti muokata ennustemallit muidenkin projektityyppien tarpeisiin. Tarkempien ennusteiden avulla voidaan kehittää johdon raportointia ja parantaa kassavirtojen ennustettavuutta.

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In this work, the fruit extracts of Morus nigra - mulberry, Syzygium cuminii - jambolão, Vitis vinifera ¾ grape, Myrciaria cauliflora - jabuticaba are suggested as pH indicators in the form of either solutions or paper. The pH indicator solutions were prepared by soaking the fruits or their peels in ethanol 1:3 (m/V) for 24 h, followed by simple filtration. The pH indicator papers were prepared by imersion of the qualitative filter paper strips in the pH indicator solutions. The different pH leads to color changes in the indicator solutions or papers and it can be used for teaching elementary chemistry concepts.