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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Across-frequency processing in convolutive blind source separation

joern@anemueller.de 30 July 2001 (has links) (PDF)
No description available.
22

Diagnosing spatial variation patterns in manufacturing processes

Lee, Ho Young 30 September 2004 (has links)
This dissertation discusses a method that will aid in diagnosing the root causes of product and process variability in complex manufacturing processes when large quantities of multivariate in-process measurement data are available. As in any data mining application, this dissertation has as its objective the extraction of useful information from the data. A linear structured model, similar to the standard factor analysis model, is used to generically represent the variation patterns that result from the root causes. Blind source separation methods are investigated to identify spatial variation patterns in manufacturing data. Further, the existing blind source separation methods are extended, enhanced and improved to be a more effective, accurate and widely applicable method for manufacturing variation diagnosis. An overall strategy is offered to guide the use of the presented methods in conjunction with alternative methods.
23

Study of ASA Algorithms

Ardam, Nagaraju January 2010 (has links)
Hearing aid devices are used to help people with hearing impairment. The number of people that requires hearingaid devices are possibly constant over the years, however the number of people that now have access to hearing aiddevices increasing rapidly. The hearing aid devices must be small, consume very little power, and be fairly accurate.Even though it is normally more important for the user that hearing impairment look good (are discrete). Once thehearing aid device prescribed to the user, she/he needs to train and adjust the device to compensate for the individualimpairment.We are within the framework of this project researching on hearing aid devices that can be trained by the hearingimpaired person her-/himself. This project is about finding suitable noise cancellation algorithm for the hearing-aiddevice. We consider several types of algorithms like, microphone array signal processing, Independent ComponentAnalysis (ICA) based on double microphone called Blind Source Separation (BSS) and DRNPE algorithm.We run this current and most sophisticated and robust algorithms in certain noise backgrounds like Cocktail noise,street, public places, train, babble situations to test the efficiency. The BSS algorithm was well in some situation andgave average results in some situations. Where one microphone gave steady results in all situations. The output isgood enough to listen targeted audio.The functionality and performance of the proposed algorithm is evaluated with different non-stationary noisebackgrounds. From the performance results it can be concluded that, by using the proposed algorithm we are able toreduce the noise to certain level. SNR, system delay, minimum error and audio perception are the vital parametersconsidered to evaluate the performance of algorithms. Based on these parameters an algorithm is suggested forheairng-aid. / Hearing-Aid
24

CCASENSE: Canonical Correlation Analysis for Estimation of Sensitivity Maps for Fast MRI

Brodin, Henrik January 2006 (has links)
Magnetic Resonance Imaging is an established technology for both imaging and functional studies in clinical and research environments. The field is still very research intense. Two major research areas are acquisition time and signal quality. The last decade has provided tools for more efficient possibilities of trading these factors against each other through parallel imaging. In this thesis one parallel imaging method, Sensitivity Encoding for fast MRI (SENSE) is examined. An alternative solution CCASENSE is developed. CCASENSE reduces the acquisition time by estimating the sensitivity maps required for SENSE to work instead of running a reference scan. The estimation process is done by Blind Source Separation through Canonical Correlation Analysis. It is shown that CCASENSE appears to estimate the sensitivity maps better than ICASENSE which is a similar algorithm.
25

Hybrid Time and Time-Frequency Blind Source Separation Towards Ambient System Identi cation of Structures

Hazra, Budhaditya January 2010 (has links)
Blind source separation methods such as independent component analysis (ICA) and second order blind identification (SOBI) have shown considerable potential in the area of ambient vibration system identification. The objective of these methods is to separate the modal responses, or sources, from the measured output responses, without the knowledge of excitation. Several frequency domain and time domain methods have been proposed and successfully implemented in the literature. Whereas frequency-domain methods pose several challenges typical of dealing with signals in the frequency-domain, popular time-domain methods such as NExT/ERA and SSI pose limitations in dealing with noise, low sensor density, modes having low energy content, or in dealing with systems having closely-spaced modes, such as those found in structures with passive energy dissipation devices, for example, tuned mass dampers.Motivated by these challenges, the current research focuses on developing methods to address the problem of separability of sources with low energy content, closely-spaced modes, and under-determined blind identification, that is, when the number of response measurements is less than the number of sources. These methods, requiring the time and frequency diversities of the measured outputs, are referred to as hybrid time and time-frequency source separation methods. The hybrid methods are classified into two categories. In the first one, the basic principles of modified SOBI are extended using the stationary wavelet transform (SWT) in order to improve the separability of sources, thereby improving the quality of identification. In the second category, empirical mode decomposition is employed to extract the intrinsic mode functions from measurements, followed by an estimation of the mode shape matrix using iterative and/or non iterative procedures within the framework of modified-SOBI. Both experimental and large-scale structural simulation results are included to demonstrate the applicability of these hybrid approaches to structural system identification problems.
26

Selective Listening Point Audio Based on Blind Signal Separation and Stereophonic Technology

TAKEDA, Kazuya, NISHINO, Takanori, NIWA, Kenta 01 March 2009 (has links)
No description available.
27

Tracking in wireless sensor network using blind source separation algorithms

Vikram, Anil Babu. January 2009 (has links)
Thesis (M.S.)--Cleveland State University, 2009. / Abstract. Title from PDF t.p. (viewed on Dec. 2, 2009). Includes bibliographical references (p. 65-72). Available online via the OhioLINK ETD Center and also available in print.
28

Ανάλυση μαγνητοεγκεφαλογραφήματος με τεχνικές τυφλού διαχωρισμού σημάτων

Λιθαρή, Χρυσούλα 22 July 2008 (has links)
Λαμβάνοντας υπ’ όψη τις διάφορες τεχνικές Blind Source Separation (BSS) που αναφέρονται στη βιβλιογραφία και που εφαρμόζονται σε πολλά πεδία ενδιαφέροντος, αποφασίσαμε να τις εφαρμόσουμε σε ανθρώπινο μαγνητοεγκεφαλογράφημα. Οι τεχνικές αυτές προσπαθούν να εξάγουν πηγές από σήμα το οποίο είναι γραμμικός συνδυασμός των πηγών. Απαραίτητη προϋπόθεση τα σήματα από τις πηγές να είναι στατιστικώς ανεξάρτητα. Πιο συγκεκριμένα, θεωρώντας τις πηγές στον εγκέφαλο ανεξάρτητες, η τεχνική που επιλέχθηκε είναι η Independent Component Analysis (ICA) και κάποιες παραλλαγές της που χρησιμοποιούν κυματίδια ώστε να εισάγουμε τη δυνατότητα περιορισμού στο χρόνο ή στο χώρο. Επιλέγοντας χωρικά ή χρονικά την περιοχή ενδιαφέροντος εστιάζουμε σε κάποια περιοχή του εγκεφάλου ή σε κάποια συγκεκριμένη χρονική στιγμή π.χ. μετά από κάποιο ερέθισμα. Θα χρησιμοποιήσουμε αυτές τις τεχνικές για να αναλύσουμε ανθρώπινο μαγνητοεγκεφαλογράφημα (MEG). Τα δεδομένα των καταγραφών είναι από το ινστιτούτο Riken στην Ιαπωνία. / Bearing in mind the Blind Source Separation Techniques mentioned in the literature and applied to many fields of interest, we decided to apply them on human MEG. These techniques extract sources from the initial signal, which is considered as linear combination of theses sources. It is required that the recorded signals are statistically independent. More specifically, considering the sources in the brain as independent, the method used is called Independent Component Analysis (ICA) and some versions which use wavelets in order to introduce spatial and temporal constraints. By selecting the region of interest either in space or in time, we focus on a region in the brain or on a specified latency e.g. after a stimulus. We use these methods to analyse MEG. The data are recorded in RIKEN institute in Japan.
29

Diagnosing spatial variation patterns in manufacturing processes

Lee, Ho Young 30 September 2004 (has links)
This dissertation discusses a method that will aid in diagnosing the root causes of product and process variability in complex manufacturing processes when large quantities of multivariate in-process measurement data are available. As in any data mining application, this dissertation has as its objective the extraction of useful information from the data. A linear structured model, similar to the standard factor analysis model, is used to generically represent the variation patterns that result from the root causes. Blind source separation methods are investigated to identify spatial variation patterns in manufacturing data. Further, the existing blind source separation methods are extended, enhanced and improved to be a more effective, accurate and widely applicable method for manufacturing variation diagnosis. An overall strategy is offered to guide the use of the presented methods in conjunction with alternative methods.
30

Hybrid Time and Time-Frequency Blind Source Separation Towards Ambient System Identi cation of Structures

Hazra, Budhaditya January 2010 (has links)
Blind source separation methods such as independent component analysis (ICA) and second order blind identification (SOBI) have shown considerable potential in the area of ambient vibration system identification. The objective of these methods is to separate the modal responses, or sources, from the measured output responses, without the knowledge of excitation. Several frequency domain and time domain methods have been proposed and successfully implemented in the literature. Whereas frequency-domain methods pose several challenges typical of dealing with signals in the frequency-domain, popular time-domain methods such as NExT/ERA and SSI pose limitations in dealing with noise, low sensor density, modes having low energy content, or in dealing with systems having closely-spaced modes, such as those found in structures with passive energy dissipation devices, for example, tuned mass dampers.Motivated by these challenges, the current research focuses on developing methods to address the problem of separability of sources with low energy content, closely-spaced modes, and under-determined blind identification, that is, when the number of response measurements is less than the number of sources. These methods, requiring the time and frequency diversities of the measured outputs, are referred to as hybrid time and time-frequency source separation methods. The hybrid methods are classified into two categories. In the first one, the basic principles of modified SOBI are extended using the stationary wavelet transform (SWT) in order to improve the separability of sources, thereby improving the quality of identification. In the second category, empirical mode decomposition is employed to extract the intrinsic mode functions from measurements, followed by an estimation of the mode shape matrix using iterative and/or non iterative procedures within the framework of modified-SOBI. Both experimental and large-scale structural simulation results are included to demonstrate the applicability of these hybrid approaches to structural system identification problems.

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