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1
Bamberger, Roberto Hugo. "The directional filter bank : a multirate filter bank for the directional decomposition of images." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/15346.
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2
Aktop, Onur. "Optimization Of Doppler Processing By Using Bank Of Matched Filters." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/12606420/index.pdf.
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In radars, matched filters are used in the receiver of the system. Since the target velocity is not known a priori, degradation occurs due to mismatch of the return signal and the matched filter. The performance of the radar can be improved by using a bank of matched filters. The first topic investigated in this work is optimization of the bank of matched filter structure. Two methods are proposed for the design of the parallel filter structure and computations are performed with both methods.
The output signal of a radar receiver filter consists not only of the main peak from the target but also of range sidelobes. In a multi-target radar environment, the sidelobes of one large target may appear as a smaller target at another range, or the integrated sidelobes from targets or clutter may mask all the information of another target. The second part of this thesis discusses the methods for decreasing the sidelobe level of the receiver output. Two methods are studied for this purpose. The first is the classical amplitude weighting and the second is the use of an inverse filter that minimizes total sidelobe energy. Both methods decrease the sidelobe levels while bringing a mismatch loss and main peak broadening. For the inverse filter case it is observed that the effect of inverse filter becomes evident as the filter length is increased beyond some point.
Finally, the effects of quantization on video signal and the receiver filter coefficients are evaluated. It is observed that 16 bits quantization is sufficient for all kinds of receiver filters tested.
3
Cadena, Pico Jorge Eduardo. "Perfect Reconstruction Filter Bank Structure Based On Interpolated FIR Filters." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71756.
Full textAbstract:
State of the art filter bank structures achieve practically perfect reconstruction with very high computational efficiency. However, the increase in computational requirements due to the need to process increasingly wider band signals is paramount. New filter bank structures that provide extra information about a signal while achieving the same level of required efficiency, and perfect reconstruction properties, need to be developed. In this work a new filter bank structure, the interpolated FIR (IFIR) filter bank is developed. Such a structure combines the concepts of filter banks, and interpolated FIR filters. The filter design procedures for the IFIR filter bank are developed and explained.
The resulting structure was compared with the non-maximally-decimated filter bank (NMDFB), achieving the same performance in terms of the number of multiplications required per sample and the overall distortion introduced by the system, when operating with Nyquist prototype filters.
In addition, the IFIR filter is tested in both simulated and real communication environments. Performance, in terms of bit-error-rate, was found to not be degraded significantly when using the IFIR filter bank system for transmission and reception of QPSK symbols.<br>Master of Science
4
Li, Min. "Induced norm optimal multirate filter bank design using LMI constraints /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202002%20LI.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.<br>Includes bibliographical references (leaves 55-58). Also available in electronic version. Access restricted to campus users.
5
Chen, Min. "Implementation and optimization of a modulated filter bank based on allpass filters." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9192.
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A filter bank based on an allpass IIR filter with brick-wall response was designed by A. J. Van Leest in [17]; however, the delay in the filter bank is too long to be used in real time applications. In order to reduce the delay, the orders of coefficients, transition bandwidth and filter bank structures must be optimized. The order of coefficients can be reduced by increasing the stopband attenuation. In order to further reduce the delay, the sharpness of the filter bank has to be reduced. This thesis also discussed the number of band and filter bank structure against to filter bank delay. The filter bank can be used in non-real time application such as CD compression with high order coefficient. The minimum transition bandwidth can be reached at 0.03257pi/number of band. This thesis expands upon DCT modulations of IIR based modulated filter banks and investigate the Hartley transformation in filter bank modulation as a new modulation technique. These modulation techniques generate the real output signal with real input signals. The quantization errors from quantizing the coefficient are studied. It is concluded that at least 16 bits are required in order for a filter bank to give a good performance as designed without quantization.
6
Nordstrom, Jeanne McDonald 1957. "The utility of using matched weight PVC filters during air sampling for particulates." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276824.
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Matched weight polyvinyl chloride (PVC) filters are currently available for use in total dust air sampling. This paper studies the utility of employing two superimposed filters in a cassette. Cassettes containing "paired" PVC filters were employed, in the same way matched weight filters would be used, during side by side sampling studies with cassettes housing single PVC filters, to determine whether the presence of two filters in a cassette presented problems during sampling. The effects of dust type, particle breakthrough, moisture concentration, and increased pressure drop from the addition of a second filter were studied. The presence of static electricity between filter pairs was also noted. Under recommended loading conditions "paired" filters seemed to perform as well as single filters in all aspects studied. Due to large filter weight variations found within individual batches of PVC filters, randomly selected filter pairs should not be used as actual matched weight filters.
7
Nallanathan, Arumugam. "Filter bank based spreading sequences: designand performance in DS/CDMA communications systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B3124077X.
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8
Nallanathan, Arumugam. "Filter bank based spreading sequences : design and performance in DS/CDMA communications systems /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21779120.
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9
Nayebi, Kambiz. "A time domain framework for the analysis and design of FIR multirate filter bank systems." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/13867.
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10
Weaver, Michael B. "Performance comparison between three different bit allocation algorithms inside a critically decimated cascading filter bank." Diss., Online access via UMI:, 2009.
Find full textAbstract:
Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Electrical and Computer Engineering, 2009.<br>Includes bibliographical references.
11
Terblanche, Phillip. "Electronically adjustable bandpass filter." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17966.
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Thesis (MScEng)--Stellenbosch University, 2011.<br>ENGLISH ABSTRACT: This thesis presents the study, analysis and design of electronically tunable filters, that can be tuned over a wide
frequency range (20-500MHz), for use in a direct sampling receiver. The final design does not have to be a
single filter, but may be comprised of a filter bank which enables switching between the filters. The band of
interest is too low to use normal transmission lines and lumped elements have to be used. Different topologies
that can implement Coupled Resonator filters with lumped elements are investigated. Devices that can be used
for tuning are also investigated and varactor diodes are found to be the most suitable tuning devices currently
available. Two filters, one at the high-end and one at the low-end of the band, were designed and built, both
using varactor diodes. These filters perform well in terms of tuning range, but achieving low losses with current
technologies in this band remains difficult.<br>AFRIKAANSE OPSOMMING: Hierdie tesis meld die studie, analise en ontwerp van elektronies verstelbare filters, wat verstelbaar is oor ’n
wye band (20-500MHz), vir gebruik in ’n direk-monster-ontvanger. Die finale ontwerp hoef nie ’n enkele filter
te wees nie, maar kan bestaan uit ’n filterbank wat skakeling tussen die filters toelaat. Die betrokke band is
te laag vir die gebruik van normale transmissielyne en diskrete komponente moet gebruik word. Verskillende
topologieë wat gekoppelde resoneerder filters implementeer met diskrete komponente is ondersoek. Verstelbare
komponente word ook ondersoek en varaktor diodes blyk die mees geskikte verstelbare komponent wat huidig
beskikbaar is in hierdie band. Twee filters, een aan die hoë kant en een aan die lae kant van die band, is ontwerp
en gebou, beide met varaktor diodes. Hierdie filters het wye verstelbare bereik, maar dit is steeds moeilik om
verliese te beperk met die huidige tegnologie.
12
Попова, М. Е., О. О. Салій та Г. В. Тарасенко. "Розробка стадії фільтрації сироватки як етап отримання депротеїнізованого гемодеривату крові телят". Thesis, Національний фармацевтичний університет, 2020. https://er.knutd.edu.ua/handle/123456789/17144.
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Плазма крові тварини – багатокомпонентний біологічний матеріал, що складається з сотень біохімічних сполук, деякі з яких ще повністю не досліджено. Метою наших досліджень було розробка та визначення критичних параметрів стадії фільтрації сироватки як одного з технологічних етапів отримання депротеінізованого гемодеривату крові телят. Доведено, що застосування мембранних фільтрів з нейлону на стадії передфільтрації є недоцільним. Мембрани з матеріалу PES забезпечують процес фільтрації сироватки крові КРС, обрані фільтри сумісні з досліджуваною сировиною. Встановлено, що використання фільтрувальних мембран у послідовності PES (0,45 мкм) та PES (0, 22 мкм) не лише гарантує відповідність необхідним показникам якості та стерильності, а й підвищує швидкість фільтрації та вихід сировини, що збільшує його економічну привабливість у промислових масштабах.<br>Animal blood plasma is a multicomponent biological material consisting of hundreds of biochemical compounds, some of which have not yet been fully studied. The aim of our research was to develop and determine the critical parameters of the stage of serum filtration as one of the technological stages of obtaining deproteinized hemoderivative of calf blood. It is proved that the use of nylon membrane filters at the stage of prefiltration is impractical. Membranes made of PES material provide the process of filtration of bovine serum, the selected filters are compatible with the test raw material. It is established that the use of filter membranes in the sequence of PES (0.45 μm) and PES (0, 22 μm) not only guarantees compliance with the required quality and sterility, but also increases filtration rate and yield of raw materials, which increases its economic attractiveness on an industrial scale.
13
Bank, Jonathan Verfasser], and Annika [Akademischer Betreuer] [Herwig. "Influence of thyroid hormones on seasonal regulation of body weight, daily torpor and gene expression in Djungarian hamsters (Phodopus sungorus) / Jonathan Bank. Betreuer: Annika Herwig." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2016. http://nbn-resolving.de/urn:nbn:de:gbv:18-80681.
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14
Bank, Jonathan [Verfasser], and Annika [Akademischer Betreuer] Herwig. "Influence of thyroid hormones on seasonal regulation of body weight, daily torpor and gene expression in Djungarian hamsters (Phodopus sungorus) / Jonathan Bank. Betreuer: Annika Herwig." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2016. http://d-nb.info/1113184442/34.
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15
Bohuš, Michal. "Návrh systému pro hlášení úniku plynu pomocí ultrazvukového mikrofonu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316449.
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The aim of this project is detection of gass leak based on the ultrasound sensing. Work introduces ultrasound, mechanism of its propagation and attenuation. From all of the available microphones, the piezoelectric microphone was chosen. Project continues with description of the device, which can be capable of detection of the ultrasound leakage in dangerous, explosive environment. This type of device must meet requirements of SIL 2 standard and ATEX directive for zone 2. Project discusses LNA (Low Noise Amplifier), filters and detection circuits design. The device is modular what means that each module can be freely replaced. The role of these modules is to convert analog signal to digital form suitable for microcontroller HERCULES TSM57012.
16
Luwes, Nicolaas Johannes. "Massabepaling van bewegende voorwerpe op 'n vervoerband met behulp van DSP-tegnieke." Thesis, Bloemfontein : Central University of Technology, Free State, 2004. http://hdl.handle.net/11462/56.
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Thesis(M. Tech.) - Central University of Technology, Free State, 2004<br>Growing markets leads to an increase in production. In these modern industries, weight measurement is of high priority. Weight measurement instrumentation is used for quality control, as well as for effective process control. Ineffective instrumentation with inaccurate data will influence the production process and profit margins negatively.
Experimental data is gathered from an angled load cell, placed as a crossover between two conveyer belts.
A weight measurement instrument with the ability to acquire accurate measurement of individual, moving parts is produced with the aid of DSP techniques. This was accomplished by analyzing the frequency spectrum for the undesirable signals with the use of Wavelets transformations (WT) and Fourier transformations (FT). After these undesired signals were identified a digital filter was designed to remove the undesired signals.
Repetition of performance is achieved by the automatic zeroing of the instrument after every individual measurement.
This weight measurement instrumentation also has the ability to store data consisting of the amount of objects and their individual weights.
This instrument can also determine the material of which an object is made of. This is done by calculating the friction coefficient. This function has the ability to effectively identify between iron and rubber components irrespective of their mass or area.
17
Sridharan, M. K. "Subband Adaptive Filtering Algorithms And Applications." Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/266.
Full textAbstract:
In system identification scenario, the linear approximation of the system modelled by its impulse response, is estimated in real time by gradient type Least Mean Square (LMS) or Recursive Least Squares (RLS) algorithms. In recent applications like acoustic echo cancellation, the order of the impulse response to be estimated is very high, and these traditional approaches are inefficient and real time implementation becomes difficult. Alternatively, the system is modelled by a set of shorter adaptive filters operating in parallel on subsampled signals. This approach, referred to as subband adaptive filtering, is expected to reduce not only the computational complexity but also to improve the convergence rate of the adaptive algorithm. But in practice, different subband adaptive algorithms have to be used to enhance the performance with respect to complexity, convergence rate and processing delay. A single subband adaptive filtering algorithm which outperforms the full band scheme in all applications is yet to be realized.
This thesis is intended to study the subband adaptive filtering techniques and explore the possibilities of better algorithms for performance improvement. Three different subband adaptive algorithms have been proposed and their performance have been verified through simulations. These algorithms have been applied to acoustic echo cancellation and EEG artefact minimization problems.
Details of the work
To start with, the fast FIR filtering scheme introduced by Mou and Duhamel has been generalized. The Perfect Reconstruction Filter Bank (PRFB) is used to model the linear FIR system. The structure offers efficient implementation with reduced arithmetic complexity. By using a PRFB with non adjacent filters non overlapping, many channel filters can be eliminated from the structure. This helps in reducing the complexity of the structure further, but introduces approximation in the model. The modelling error depends on the stop band attenuation of the filters of the PRFB. The error introduced due to approximation is tolerable
for applications like acoustic echo cancellation.
The filtered output of the modified generalized fast filtering structure is given by
(formula)
where, Pk(z) is the main channel output, Pk,, k+1 (z) is the output of auxiliary channel filters at the reduced rate, Gk (z) is the kth synthesis filter and M the number of channels in the PRFB. An adaptation scheme is developed for adapting the main channel filters. Auxiliary channel filters are derived from main channel filters.
Secondly, the aliasing problem of the classical structure is reduced without using the cross filters. Aliasing components in the estimated signal results in very poor steady state performance in the classical structure. Attempts to eliminate the aliasing have reduced the computation gain margin and the convergence rate. Any attempt to estimate the subband reference signals from the aliased subband input signals results in aliasing. The analysis filter Hk(z) having the following antialiasing property
(formula)
can avoid aliasing in the input subband signal. The asymmetry of the frequency response prevents the use of real analysis filters. In the investigation presented in this thesis, complex analysis filters and real'synthesis filters are used in the classical structure, to reduce the aliasing errors and to achieve superior convergence rate.
PRFB is traditionally used in implementing Interpolated FIR (IFIR) structure. These filters may not be ideal for processing an input signal for an adaptive algorithm. As third contribution, the IFIR structure is modified using discrete finite frames. The model of an FIR filter s is given by Fc, with c = Hs. The columns of the matrix F forms a frame with rows of H as its dual frame. The matrix elements can be arbitrary except that the transformation should be implementable as a filter bank. This freedom is used to optimize the filter bank, with the knowledge of the input statistics, for initial convergence rate enhancement .
Next, the proposed subband adaptive algorithms are applied to acoustic echo cancellation problem with realistic parameters. Speech input and sufficiently long Room Impulse Response (RIR) are used in the simulations. The Echo Return Loss Enhancement (ERLE)and the steady state error spectrum are used as performance measures to compare these algorithms with the full band scheme and other representative subband implementations.
Finally, Subband adaptive algorithm is used in minimization of EOG (Electrooculogram) artefacts from measured EEG (Electroencephalogram) signal. An IIR filterbank providing sufficient isolation between the frequency bands is used in the modified IFIR structure and this structure has been employed in the artefact minimization scheme. The estimation error in the high frequency range has been reduced and the output signal to noise ratio has been increased by a couple of dB over that of the fullband scheme.
Conclusions
Efforts to find elegant Subband adaptive filtering algorithms will continue in the future. However, in this thesis, the generalized filtering algorithm could offer gain in filtering complexity of the order of M/2 and reduced misadjustment . The complex classical scheme offered improved convergence rate, reduced misadjustment and computational gains of the order of M/4 . The modifications of the IFIR structure using discrete finite frames made it possible to eliminate the processing delay and enhance the convergence rate. Typical performance of the complex classical case for speech input in a realistic scenario (8 channel case), offers ERLE of more than 45dB. The subband approach to EOG artefact minimization in EEG signal was found to be superior to their fullband counterpart.
(Refer PDF file for Formulas)
18
Sridharan, M. K. "Subband Adaptive Filtering Algorithms And Applications." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/266.
Full textAbstract:
In system identification scenario, the linear approximation of the system modelled by its impulse response, is estimated in real time by gradient type Least Mean Square (LMS) or Recursive Least Squares (RLS) algorithms. In recent applications like acoustic echo cancellation, the order of the impulse response to be estimated is very high, and these traditional approaches are inefficient and real time implementation becomes difficult. Alternatively, the system is modelled by a set of shorter adaptive filters operating in parallel on subsampled signals. This approach, referred to as subband adaptive filtering, is expected to reduce not only the computational complexity but also to improve the convergence rate of the adaptive algorithm. But in practice, different subband adaptive algorithms have to be used to enhance the performance with respect to complexity, convergence rate and processing delay. A single subband adaptive filtering algorithm which outperforms the full band scheme in all applications is yet to be realized.
This thesis is intended to study the subband adaptive filtering techniques and explore the possibilities of better algorithms for performance improvement. Three different subband adaptive algorithms have been proposed and their performance have been verified through simulations. These algorithms have been applied to acoustic echo cancellation and EEG artefact minimization problems.
Details of the work
To start with, the fast FIR filtering scheme introduced by Mou and Duhamel has been generalized. The Perfect Reconstruction Filter Bank (PRFB) is used to model the linear FIR system. The structure offers efficient implementation with reduced arithmetic complexity. By using a PRFB with non adjacent filters non overlapping, many channel filters can be eliminated from the structure. This helps in reducing the complexity of the structure further, but introduces approximation in the model. The modelling error depends on the stop band attenuation of the filters of the PRFB. The error introduced due to approximation is tolerable
for applications like acoustic echo cancellation.
The filtered output of the modified generalized fast filtering structure is given by
(formula)
where, Pk(z) is the main channel output, Pk,, k+1 (z) is the output of auxiliary channel filters at the reduced rate, Gk (z) is the kth synthesis filter and M the number of channels in the PRFB. An adaptation scheme is developed for adapting the main channel filters. Auxiliary channel filters are derived from main channel filters.
Secondly, the aliasing problem of the classical structure is reduced without using the cross filters. Aliasing components in the estimated signal results in very poor steady state performance in the classical structure. Attempts to eliminate the aliasing have reduced the computation gain margin and the convergence rate. Any attempt to estimate the subband reference signals from the aliased subband input signals results in aliasing. The analysis filter Hk(z) having the following antialiasing property
(formula)
can avoid aliasing in the input subband signal. The asymmetry of the frequency response prevents the use of real analysis filters. In the investigation presented in this thesis, complex analysis filters and real'synthesis filters are used in the classical structure, to reduce the aliasing errors and to achieve superior convergence rate.
PRFB is traditionally used in implementing Interpolated FIR (IFIR) structure. These filters may not be ideal for processing an input signal for an adaptive algorithm. As third contribution, the IFIR structure is modified using discrete finite frames. The model of an FIR filter s is given by Fc, with c = Hs. The columns of the matrix F forms a frame with rows of H as its dual frame. The matrix elements can be arbitrary except that the transformation should be implementable as a filter bank. This freedom is used to optimize the filter bank, with the knowledge of the input statistics, for initial convergence rate enhancement .
Next, the proposed subband adaptive algorithms are applied to acoustic echo cancellation problem with realistic parameters. Speech input and sufficiently long Room Impulse Response (RIR) are used in the simulations. The Echo Return Loss Enhancement (ERLE)and the steady state error spectrum are used as performance measures to compare these algorithms with the full band scheme and other representative subband implementations.
Finally, Subband adaptive algorithm is used in minimization of EOG (Electrooculogram) artefacts from measured EEG (Electroencephalogram) signal. An IIR filterbank providing sufficient isolation between the frequency bands is used in the modified IFIR structure and this structure has been employed in the artefact minimization scheme. The estimation error in the high frequency range has been reduced and the output signal to noise ratio has been increased by a couple of dB over that of the fullband scheme.
Conclusions
Efforts to find elegant Subband adaptive filtering algorithms will continue in the future. However, in this thesis, the generalized filtering algorithm could offer gain in filtering complexity of the order of M/2 and reduced misadjustment . The complex classical scheme offered improved convergence rate, reduced misadjustment and computational gains of the order of M/4 . The modifications of the IFIR structure using discrete finite frames made it possible to eliminate the processing delay and enhance the convergence rate. Typical performance of the complex classical case for speech input in a realistic scenario (8 channel case), offers ERLE of more than 45dB. The subband approach to EOG artefact minimization in EEG signal was found to be superior to their fullband counterpart.
(Refer PDF file for Formulas)
19
Hammarqvist, Ulf. "Audio editing in the time-frequency domain using the Gabor Wavelet Transform." Thesis, Uppsala universitet, Centrum för bildanalys, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-153634.
Full textAbstract:
Visualization, processing and editing of audio, directly on a time-frequency surface, is the scope of this thesis. More precisely the scalogram produced by a Gabor Wavelet transform is used, which is a powerful alternative to traditional techinques where the wave form is the main visual aid and editting is performed by parametric filters. Reconstruction properties, scalogram design and enhancements as well audio manipulation algorithms are investigated for this audio representation.The scalogram is designed to allow a flexible choice of time-frequency ratio, while maintaining high quality reconstruction. For this mean, the Loglet is used, which is observed to be the most suitable filter choice. Re-assignmentare tested, and a novel weighting function using partial derivatives of phase is proposed. An audio interpolation procedure is developed and shown to perform well in listening tests.The feasibility to use the transform coefficients directly for various purposes is investigated. It is concluded that Pitch shifts are hard to describe in the framework while noise thresh holding works well. A downsampling scheme is suggested that saves on operations and memory consumption as well as it speeds up real world implementations significantly. Finally, a Scalogram 'compression' procedure is developed, allowing the caching of an approximate scalogram.
20
Ondra, Josef. "Komprese signálů EKG s využitím vlnkové transformace." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217209.
Full textAbstract:
Signal compression is daily-used tool for memory capacities reduction and for fast data communication. Methods based on wavelet transform seem to be very effective nowadays. Signal decomposition with a suitable bank filters following with coefficients quantization represents one of the available technique. After packing quantized coefficients into one sequence, run length coding together with Huffman coding are implemented. This thesis focuses on compression effectiveness for the different wavelet transform and quantization settings.
21
Hanzálek, Pavel. "Praktické ukázky zpracování signálů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400849.
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The thesis focuses on the issue of signal processing. Using practical examples, it tries to show the use of individual signal processing operations from a practical point of view. For each of the selected signal processing operations, an application is created in MATLAB, including a graphical interface for easier operation. The division of the thesis is such that each chapter is first analyzed from a theoretical point of view, then it is shown using a practical demonstration of what the operation is used in practice. Individual applications are described here, mainly in terms of how they are handled and their possible results. The results of the practical part are presented in the attachment of the thesis.
22
Kirthi, Suresh K. "Multisource Subnetwork Level Transfer in Deep CNNs Using Bank of Weight Filters." Thesis, 2019. https://etd.iisc.ac.in/handle/2005/5444.
Full textAbstract:
The convolutional neural networks (CNNs) have become the most successful models for many
pattern recognition problems in the areas of computer vision, speech, text and others. One
concern about CNNs has always been their need for large amount of training data, large computational
re- sources and long training time. In this regard the transfer learning is a technique
that can address this concern of inefficient CNN training through reuse of pretrained networks
(CNNs). In this thesis we discuss transfer learning in CNNs where the transfer is from multiple
source CNNs and done at subnetwork levels. The subnetwork multisource transfer is attempted
for the fi rst time and hence we begin by showing the effectiveness of such a transfer. We consider
subnetworks at various granularities for the transfer. These granularities begin at a whole
network-level then pro-ceed to layer-level and further fi lter-level. In order to realize this kind
of transfer we create a set called bank of weight fi lters (BWF) which is a repository of the pretrained
subnetworks that are used as candidates for transfer. Through extensive simulations we
show that subnetwork level transfer, implemented through random selection from a BWF, is
elective and is also efficient in terms of training time. We also present experimental results to
show that subnetwork level transfer learning is efficient in terms of the amount of training data
needed. It is seen that fi lter-level transfer learning is as effective as the whole-network-level
transfer which is the conventional transfer learning used with CNNs. We then show the usefulness
of the fi lter-level multisource transfer for the cases of transfer from natural to non-natural
(hand drawn sketches) image datasets and transfer across different CNN architectures (having
different number of layers, fi lter dimensions etc.). We also discuss transfer from CNNs trained
on high-resolution images to the CNNs needed for the low-resolution im- ages and vice-versa.
In the multisource transfer of prelearnt weights discussed above, the transferred weights have
to be fi netuned to achieve the same accuracy as that of a CNN trained from scratch. It is
certainly more bene cfiial and efficient if the fi netuning of transferred weights can be completely
avoided. For this, we conceptualize we conceptualize what we call a fi lter-tree which represents
the complete feature generation entity that is learnt by a CNN and propose that the a
filter-tree represents a subnetwork that can be used for transfer without finetuning. Similar
to BWF we create a repository of pre-learnt fllter-trees called bank of filter-trees (BFT) to
realize the transfer using fi lter-trees. Through experiments we show that transfer using BFT
(where the transferred weights are held fixed and are not fi netunes) has performance that is on
par with training from scratch, which is the best achievable performance. The selection of the
subnetworks from BWF or BFT so far for all experiments was done uniformly randomly. For
the sake of completion we introduce a method that can result in informed choice of fi lters from
a BFT. We propose a learnable auxilliary layer called choice layer whose learnt weights give
an idea of the importance/utility of different the subnetwork (fi lter-trees here) in the BFT for
the target task. We show that when the random choice from BFT does not achieve the best
possible accuracy, the choice layer based method can achieve it.
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Lee, Chia-Cheng, and 李嘉政. "GPS Satellite Fault Detection and Exclusion Using Bank of Kalman Filters." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/gnn3t5.
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碩士<br>國立臺灣大學<br>電機工程學研究所<br>92<br>Abstract
In this thesis, a new approach based on the bank of Kalman filters is proposed to reduce the fault detection time and the incorrect exclusion rate. The dynamic behavior of the failure vector can be described as P-V (position-velocity) model。By applying the bank of the Kalman filters, the updated fault value can be obtained. Furthermore, the test statistic can be constructed from the fault value. By hypothesis testing, the detection threshold under a given false alarm rate can be calculated directly. Simulation results show that in comparison with the parity-space method, the best improvement of percentage for average detection time is 84.3% and the best improvement of percentage for incorrect exclusion rate is 100% under the step-type failure Also the best improvement of percentage for average detection time is 45.6% and the best improvement of percentage for incorrect exclusion rate is 100% under the ramp-type failure.. The method of the bank of the Kalman filters is better than the method of the parity-space method both in average detection time and incorrect exclusion rate when the fault value is small. Both methods are almost the same in detection time when the fault value is big. Therefore by use of the bank of Kalman filters can monitor the small fault value to keep GPS working continuously. At the end of thesis the concept of the modified bank of Kalman filters is proposed to reduce the number of Kalman filters. From the observerbility analysis, the upper bound of the number of satellites to be monitored by one Kalman filter is obtained.
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ElGarewi, Ahmed. "Analysis of algorithms for filter bank design optimization." Thesis, 2019. http://hdl.handle.net/1828/11131.
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This thesis deals with design algorithms for filter banks based on optimization. The design specifications consist of the perfect reconstruction and frequency response specifications for finite impulse response (FIR) analysis and synthesis filters. The perfect reconstruction conditions are formulated as a set of linear equations with respect to the analysis filters’ coefficients and the synthesis filters’ coefficients. Five design algorithms are presented. The first three are based on an unconstrained optimization of performance indices, which include the perfect reconstruction error and the error in the frequency specifications. The last two algorithms are formulated as constrained optimization problems with the perfect reconstruction error as the performance index and the frequency specifications as constraints. The performance of the five algorithms is evaluated and compared using six examples; these examples include uniform filter bank, compatible non-uniform filter bank and incompatible non-uniform filter bank designs. The evaluation criteria are based on distortion and aliasing errors, the magnitude response characteristics of analysis and synthesis filters, the computation time required for the optimization, and the convergence of the performance index with respect to the number of iterations. The results show that the five algorithms can achieve almost perfect reconstruction and can meet the frequency response specifications at an acceptable level. In the case of incompatible non-uniform filter banks, the algorithms have challenges to achieve almost perfect reconstruction.<br>Graduate
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Pan, Hong-Shiuann, and 潘宏炫. "A Filter Bank Multicarrier System Based on the Discrete Hartley Transform and Two Prototype Filters." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8t5yqv.
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Chou, Che-Hao, and 周哲豪. "Time Synchronization for a Filter Bank Multicarrier System Based on the Discrete Hartley Transform and Two Prototype Filters." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/f6m83n.
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YEH, CHE-CHUN, and 葉哲君. "The Impact of SME Bank Relationship and Loan Risk Weight on Default Risk: Regional Loan Data in Taiwan." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/36w78j.
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碩士<br>南華大學<br>財務金融學系財務管理碩士班<br>106<br>Collecting the data on credit lending contracts of SMEs from the branches of a listed commercial bank in Yun Jia Nan in Taiwan over 2012-2017, this thesis empirically explores the relationship between current and future (number of contacts, number of years, risk weights , the overall contribution), and whether the main bank is a government-owned bank, the probability of default on SMEs, empirical methods using GLS Panel Data Model and Stata statistical software to estimate. The empirical results support the SME credit accounts when their contacts with banks and the number of households more, the risk of default for SMEs will be significantly reduced; the same time, if the main banks can increase the amount of bank credit, SME default risk will be significant In particular, the risk of default by SMEs will also be reduced during the financial turmoil. In addition, if the SME's main bank is the branch with more bankers at the same time, the amount of credit granted to SMEs will also be higher but the interest rate plus the number of plus-plus markings. At the same time, if the SME does not take this branch as Main banks, the amount of credit they get will be increased, but access to lower interest rates plus. In addition, the lower the overall credit risk weight or the overall contribution of SMEs, the amount of credit granted to SMEs will also increase, and a lower rate of interest plus bonus will be obtained.
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Venkataraman, S. "On Adaptive Filtering Using Delayless IFIR Structure : Analysis, Experiments And Application To Active Noise Control And Acoustic Echo Cancellation." Thesis, 2005. https://etd.iisc.ac.in/handle/2005/1436.
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Venkataraman, S. "On Adaptive Filtering Using Delayless IFIR Structure : Analysis, Experiments And Application To Active Noise Control And Acoustic Echo Cancellation." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1436.
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ALGERI, CARMELO. "Four Essays on Spatial Dependence Effects of Local Banks." Doctoral thesis, 2020. http://hdl.handle.net/11570/3182313.
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In this study I consider the effects of the inclusion of spatial dependence in the empirical model measuring the small-cooperative banks' risk performance. If there exists cross sectional dependence, spatial analysis deals with co-movement among geographical units, allowing the evaluation of spillover effects and ameliorating econometric models. I provide several contributions to the literature. First, I support the hypothesis that the inclusion of spatial terms improves the small bank soundness models. Second, since I control for the banks' market power, I expand the literature on the relationship between bank risk and market competitive pressure. Third, I find empirical evidence that the bank size does not affect the financial standing of the small banks. Finally, as I proxy bank soundness with the Z-Score index, I indirectly test the impacts on small firms of the relationship lending, a classic tool adopted by the small banks to assess the creditworthiness of small firms. My results strongly support the hypothesis that risk-performance bank models are enhanced with spatial variables and that relationship lending makes small firm loan demand low price-elastic.<br>A steady stream of literature has emphasized that small and local banks benefit from market power against large banks due to their ability to use soft information. Such banks serve small and micro enterprises and households; that is, niche markets from which large banks are usually barred. In light of this, I applied a spatial analysis methodology to test the hypothesis that the technical efficiency performance of local Italian banks is affected by spatial dependence. I posited that local banks mainly compete among themselves, and that the market discipline creates efficiency in this scenario. Using data envelopment analysis (DEA) methodology, I estimated the efficiency score at bank level and, in a second step, carried out a truncated bootstrap regression. My results provide robust evidence that spatial dependence has a positive effect on both the input and the output technical efficiency of local banks for three specifications based on specific spatial matrices while, for greater distances, the spatial lag parameter was not more statistically significant. Furthermore, in some cases, the spatial covariates had the opposite effect on a bank's technical efficiency compared to the same variables when considered alone. This result highlights that the level of a bank's strategy can contradict the effect of general market tendencies on a bank's performance in terms of efficiency.<br>In this study, I consider the spatial dependence effects in an empirical model measuring local banks' tax aggressiveness, assessing the interdependence between geographical units and the related spillover effects. My results strongly support the existence of co-movements among banks' tax avoidance policies. The findings indicate that local banks compete mainly among themselves, even on the funding side, and that certain tax behavior can trigger loss of customers, which limits banks' tax avoidance activities. However, neighbors' adoption of aggressive tax strategies can remove the competition hurdle in pursuing tax avoidance policies. In addition, I find that greater bank market power increases spatial spillover effects, showing that neighbors' tax management strategies matter in planning a local bank's tax policies. These findings point out a virtuous effect of customer pressure, which could take effect in other areas of bank management.<br>This study investigates the existence of spatial dependence in the Non-Performing Loans ratio of Italian small cooperative banks, a model of local banking. Since these banks operate in a delimited area, their recovery strategies for bad loans can produce spatial spillover effects in neighboring banks' ability to recover credit. My empirical estimations provide strong evidence that both spatial and spatial-temporal variables improve the analytical model by identifying the drivers of impaired loans for local banks. Specifically, the empirical results underline a different effect of the spatial terms, highlighting a direct impact of the contemporaneous spatial lag variable and a negative effect of the space-time autoregressive coefficient. Whereas the former effects can be ascribed to changes in the macroeconomic cycle, the latter confirms the insight that neighboring credit recovery policies can harm local banks' recovery abilities. Moreover, I also control for market power at the bank level, providing evidence supporting the competition-stability view.
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Moazzen, Iman. "Array Signal Processing for Beamforming and Blind Source Separation." Thesis, 2013. http://hdl.handle.net/1828/4580.
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A new broadband beamformer composed of nested arrays (NAs), multi-dimensional (MD) filters, and multirate techniques is proposed for both linear and planar arrays. It is shown that this combination results in frequency-invariant response. For a given number of sensors, the advantage of using NAs is that the effective aperture for low temporal frequencies is larger than in the case of using uniform arrays. This leads to high spatial selectivity for low frequencies. For a given aperture size, the proposed beamformer can be implemented with significantly fewer sensors and less computation than uniform arrays with a slight deterioration in performance. Taking advantage of the Noble identity and polyphase structures, the proposed method can be efficiently implemented. Simulation results demonstrate the good performance of the proposed beamformer in terms of frequency-invariant response and computational requirements.
The broadband beamformer requires a filter bank with a non-compatible set of sampling rates which is challenging to be designed. To address this issue, a filter bank design approach is presented. The approach is based on formulating the design problem as an optimization problem with a performance index which consists of a term depending on perfect reconstruction (PR) and a term depending on the magnitude specifications of the analysis filters. The design objectives are to achieve almost perfect reconstruction (PR) and have the analysis filters satisfying some prescribed frequency specifications. Several design examples are considered to show the satisfactory performance of the proposed method.
A new blind multi-stage space-time equalizer (STE) is proposed which can separate narrowband sources from a mixed signal. Neither the direction of arrival (DOA) nor a training sequence is assumed to be available for the receiver. The beamformer and equalizer are jointly updated to combat both co-channel interference (CCI) and inter-symbol interference (ISI) effectively. Using subarray beamformers, the DOA, possibly time-varying, of the captured signal is estimated and tracked. The estimated DOA is used by the beamformer to provide strong CCI cancellation. In order to alleviate inter-stage error propagation significantly, a mean-square-error sorting algorithm is used which assigns detected sources to different stages according to the reconstruction error at different stages. Further, to speed up the convergence, a simple-yet-efficient DOA estimation algorithm is proposed which can provide good initial DOAs for the multi-stage STE. Simulation results illustrate the good performance of the proposed STE and show that it can effectively deal with changing DOAs and time variant channels.<br>Graduate<br>0544<br>imanmoaz@uvic.ca