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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.
171

Towards more robust fingerprint verification.

January 2005 (has links)
Yeung Hoi Wo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 81-88). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.10 / Chapter 1.1 --- Biometric Systems --- p.1 / Chapter 1.2 --- Comparison of Biometrics --- p.2 / Chapter 1.3 --- Introduction of Fingerprint --- p.6 / Chapter 1.3.1 --- History of Fingerprint --- p.6 / Chapter 1.3.2 --- Fingerprint Analysis --- p.8 / Chapter 1.4 --- Fingerprint Verification --- p.13 / Chapter 1.4.1 --- Correlation Based Verification: --- p.13 / Chapter 1.4.2 --- Minutiae Based Verification: --- p.15 / Chapter 1.4.3 --- Ridge Feature-Based Verification: --- p.16 / Chapter 1.5 --- Evaluation of Verification Systems --- p.17 / Chapter 1.6 --- Difficulties of Fingerprint Verification --- p.22 / Chapter 1.7 --- Contributions --- p.25 / Chapter 1.8 --- Organization of the Thesis --- p.26 / Chapter 2. --- Two-Pass Direct Gray-Scale for Minutiae Detection --- p.28 / Chapter 2.1 --- Introduction --- p.28 / Chapter 2.2 --- Background Information --- p.29 / Chapter 2.3 --- Two-Pass Direct Gray Scale --- p.34 / Chapter 2.3.1 --- First Pass of TPD --- p.38 / Chapter 2.3.2 --- Second Pass of TPD --- p.41 / Chapter 2.4 --- Other Implementation Details --- p.44 / Chapter 2.4.1 --- Foreground Detection --- p.45 / Chapter 2.4.2 --- Region of Interest Detection --- p.48 / Chapter 2.4.3 --- Matching Methodology --- p.52 / Chapter 2.5 --- Experimental Results --- p.58 / Chapter 2.6 --- Summary --- p.62 / Chapter 3. --- Image Mosaicking and Template Synthesis --- p.63 / Chapter 3.1 --- Introduction --- p.63 / Chapter 3.2 --- Background Information --- p.65 / Chapter 3.3 --- Template Synthesis and Image Mosaicking --- p.66 / Chapter 3.3.1 --- Template Alignment --- p.66 / Chapter 3.3.2 --- Template Synthesis --- p.68 / Chapter 3.3.3 --- Image Mosaicking --- p.70 / Chapter 3.4 --- Experiments --- p.72 / Chapter 3.5 --- Summary --- p.75 / Chapter 4. --- Conclusion and Future Investigations --- p.77 / References --- p.81
172

Implementering av multivariabel reglering i DCS-miljö / Implementation of multivariable control in DCS-environment

Winberg, Johan January 2009 (has links)
<p>Inom processindustrin finns en etablerad reglerhierarki där basreglering sker med PID-regulatorer och där avancerad, multivariabel styrning sköts av MPC-programvara. Steget mellan dessa två nivåer kan upplevas som stort. För mindre och snabba multivariabla processer undvikes helst en multivariabel ansats, med försämrad reglering som följd. På Preem AB har detta upplevts som ett problem. Syftet med examensarbetet har varit att utveckla en alternativ, multivariabel styrstrategi för en process med ett mindre antal reglerstorheter som interagerar. Detta har gjorts genom en utveckling av en LQG-regulator i styrsystemet DeltaV.</p><p>För att implementera en regulator i ett styrsystem måste hänsyn tas till en rad faktorer, såsom hantering av olika körlägen, bortfall av signaler, integratoruppvridning, kommunikation med slavregulatorer och inte minst operatörernas gränssnitt för hantering av regulatorn. Att sedan utveckla en regulator för en process kräver bland annat stegförsök, analys och anpassning av stegtestdata, modellidentifiering, framtagning av trimningskonstanter, testning av styrstrategi i simulerad miljö och idrifttagning. Den typen av frågeställningar addresseras i rapporten.</p><p>Examensarbetet visar att det finns en plats för LQG-regulatorn i processindustrin för en viss typ av problem. Den utvecklade regulatorn har implementerats på en avsvavlingsprocess på Preems oljeraffenaderi i Lysekil med lyckat resultat. Oscillationer i processen, som tidvis påverkat produktionen av propen, har kunnat reduceras.</p> / <p>Process control in process industry is done in a hierarchy in which PID controllers are used for basic control and MPC software is used for advanced, multivariable process control. The implementation of multivariable control using MPC software is a major undertaking and development of such controllers for small and fast multivariable processes is therefore avoided. To achieve better control for such processes, a simpler approach to multivariable control is often sought. The purpose of this masters thesis is to develop an alternative, multivariable control strategy for processes with a smaller number of interacting control variables. This is achieved by developing an LQG-controller in the DCS DeltaV at Preem AB.</p><p>Implementation of such a controller in a DCS requires that consideration is given to a number of factors, including handling of different modes, loss of signals, reset windup, communication with slave controllers and construction of operator interface. To develop a controller for a specific process also requires step testing, model identification, tuning of the controller parameters, simulation of the control strategy and commissioning. Solutions to such issues are addressed in this report.</p><p>The thesis shows that  LQG-controllers can be useful in process industry for some niche applications. The LQG-controller has successfully been applied to a desulphurisation process at Preem's oil refinery in Lysekil, where oscillations affecting the production of propylene have been reduced.</p>
173

Structural Reformulations in System Identification

Lyzell, Christian January 2012 (has links)
In system identification, the choice of model structure is important and it is sometimes desirable to use a flexible model structure that is able to approximate a wide range of systems. One such model structure is the Wiener class of systems, that is, systems where the input enters a linear time-invariant subsystem followed by a time-invariant nonlinearity. Given a sequence of input and output pairs, the system identification problem is often formulated as the minimization of the mean-square prediction error. Here, the prediction error has a nonlinear dependence on the parameters of the linear subsystem and the nonlinearity. Unfortunately, this formulation of the estimation problem is often nonconvex, with several local minima, and it is therefore difficult to guarantee that a local search algorithm will be able to find the global optimum. In the first part of this thesis, we consider the application of dimension reduction methods to the problem of estimating the impulse response of the linear part of a system in the Wiener class. For example, by applying the inverse regression approach to dimension reduction, the impulse response estimation problem can be cast as a principal components problem, where the reformulation is based on simple nonparametric estimates of certain conditional moments. The inverse regression approach can be shown to be consistent under restrictions on the distribution of the input signal provided that the true linear subsystem has a finite impulse response. Furthermore, a forward approach to dimension reduction is also considered, where the time-invariant nonlinearity is approximated by a local linear model. In this setting, the impulse response estimation problem can be posed as a rank-reduced linear least-squares problem and a convex relaxation can be derived. Thereafter, we consider the extension of the subspace identification approach to include linear time-invariant rational models. It turns out that only minor structural modifications are needed and already available implementations can be used. Furthermore, other a priori information regarding the structure of the system can incorporated, including a certain class of linear gray-box structures. The proposed extension is not restricted to the discrete-time case and can be used to estimate continuous-time models. The final topic in this thesis is the estimation of discrete-time models containing polynomial nonlinearities. In the continuous-time case, a constructive algorithm based on differential algebra has previously been used to prove that such model structures are globally identifiable if and only if they can be written as a linear regression model. Thus, if we are able to transform the nonlinear model structure into a linear regression model, the parameter estimation problem can be solved with standard methods. Motivated by the above and the fact that most system identification problems involve sampled data, a discrete-time version of the algorithm is developed. This algorithm is closely related to the continuous-time version and enables the handling of noise signals without differentiations.
174

Development of PCR-based markers for identifying grape rootstocks

Xu, Hong, 1968- 30 June 1995 (has links)
Sequence-specific PCR markers were derived from one new and eight previously identified random amplified polymorphic DNA (RAPD) markers for the purpose of identifying grape (Vitis) rootstocks. The markers were developed because the RAPD assay was found to be inconsistent and the original RAPD markers unreliable. Southern hybridization analysis of the RAPD gels with cloned RAPD bands as probes revealed deficiencies of scoring RAPD bands based solely on ethidium bromide staining. In one case, bands of the same size generated by the same primer in different rootstocks -- normally scored as the same marker -- failed to cross-hybridize, implying a lack of homology between the bands. In another case, a band scored as absent based on ethidium bromide staining was detected by hybridization. One of nine RAPD bands was cloned in the present study. All nine were partially sequenced and sequence-specific pairs of primers were synthesized for each for use under stringent PCR conditions. Three of the primer pairs generated products only from the rootstocks from which the original RAPD bands had been cloned; three others produced products from additional rootstocks while still generating polymorphisms; two others generated apparent length variants from some accessions; and one primer pair resulted in a loss of polymorphism. Based on the eight polymorphic markers, five of nine rootstocks could be unambiguously distinguished. / Graduation date: 1996
175

Implementering av multivariabel reglering i DCS-miljö / Implementation of multivariable control in DCS-environment

Winberg, Johan January 2009 (has links)
Inom processindustrin finns en etablerad reglerhierarki där basreglering sker med PID-regulatorer och där avancerad, multivariabel styrning sköts av MPC-programvara. Steget mellan dessa två nivåer kan upplevas som stort. För mindre och snabba multivariabla processer undvikes helst en multivariabel ansats, med försämrad reglering som följd. På Preem AB har detta upplevts som ett problem. Syftet med examensarbetet har varit att utveckla en alternativ, multivariabel styrstrategi för en process med ett mindre antal reglerstorheter som interagerar. Detta har gjorts genom en utveckling av en LQG-regulator i styrsystemet DeltaV. För att implementera en regulator i ett styrsystem måste hänsyn tas till en rad faktorer, såsom hantering av olika körlägen, bortfall av signaler, integratoruppvridning, kommunikation med slavregulatorer och inte minst operatörernas gränssnitt för hantering av regulatorn. Att sedan utveckla en regulator för en process kräver bland annat stegförsök, analys och anpassning av stegtestdata, modellidentifiering, framtagning av trimningskonstanter, testning av styrstrategi i simulerad miljö och idrifttagning. Den typen av frågeställningar addresseras i rapporten. Examensarbetet visar att det finns en plats för LQG-regulatorn i processindustrin för en viss typ av problem. Den utvecklade regulatorn har implementerats på en avsvavlingsprocess på Preems oljeraffenaderi i Lysekil med lyckat resultat. Oscillationer i processen, som tidvis påverkat produktionen av propen, har kunnat reduceras. / Process control in process industry is done in a hierarchy in which PID controllers are used for basic control and MPC software is used for advanced, multivariable process control. The implementation of multivariable control using MPC software is a major undertaking and development of such controllers for small and fast multivariable processes is therefore avoided. To achieve better control for such processes, a simpler approach to multivariable control is often sought. The purpose of this masters thesis is to develop an alternative, multivariable control strategy for processes with a smaller number of interacting control variables. This is achieved by developing an LQG-controller in the DCS DeltaV at Preem AB. Implementation of such a controller in a DCS requires that consideration is given to a number of factors, including handling of different modes, loss of signals, reset windup, communication with slave controllers and construction of operator interface. To develop a controller for a specific process also requires step testing, model identification, tuning of the controller parameters, simulation of the control strategy and commissioning. Solutions to such issues are addressed in this report. The thesis shows that  LQG-controllers can be useful in process industry for some niche applications. The LQG-controller has successfully been applied to a desulphurisation process at Preem's oil refinery in Lysekil, where oscillations affecting the production of propylene have been reduced.
176

Studies on the Election Factors of the Voters

Chen, Ko-Ru 10 July 2008 (has links)
This research explores whether ¡§party identification, candidate orientation, ethnic identification and issue orientation,¡¨ the four intermediate variables of election, are correlated to the results of Taipei mayor elections in 2002 and 2006. The data in this research are mainly based on the interview broadly carried out to collect facts for ¡§the study on democratization through election¡¨ executed by Professors Huang Chi and Huang Siu-Twen in 2002 and 2005. It is with these data that this research compares the voting behavior of the voters in the two mayor elections in an attempt to find out the deviation of election for further studies. Each individual voter has of his own a variety of social backgrounds which inevitably form to some extent a connection with each of the four intermediate variables. In examination of the connection just mentioned, it is obvious that of all the voter¡¦s backgrounds the place of birth is probably the most potential and influential, and has a significant connection with each of the four factors. However, an evaluation of the connection between the voting preference and the four factors indicates that the four factors are apparently convincing in justification of the results of the second Taipei mayor election in 2006. In addition, a detailed analysis of the connections between voter¡¦s social backgrounds and his voting preference shows that the voter¡¦s place of birth plays an important role in making his voting preference. Other social backgrounds except the voter¡¦s educational level are slightly related to the voting preference in the Taipei mayor election in 2006. Based on the analysis mentioned above, it is understood that there are many variables which will influence the voting preference. Of all the intermediate variables, however, the four factors of party identification candidate orientation ethnic identification and issue orientation are perhaps most crucial and decisive. By means of the analysis and evaluation of the four factors functioning in the recent elections, it is discovered that the people here in Taiwan are relatively better educated and have made a tremendous progress in democracy. It seems that Taiwan has already developed into a nation of two-party politics.
177

Approche biométrique pour l'identification automatique des produits bois

Fuentealba, Cecilia Charpentier, Patrick. January 2005 (has links) (PDF)
Thèse doctorat : Sciences du bois : Nancy 1 : 2005. / Titre provenant de l'écran-titre.
178

Some boring insects from the roots of Haplopappus tenuisectus, Gutierrezia microcephala, G. sarothrae, and G. serotina in southern Arizona

Hetz, Martin William January 1979 (has links)
No description available.
179

Classification and identification of yeasts by Fourier transform infrared spectroscopy

Zhao, Jianming, 1972- January 2000 (has links)
Infrared spectra of microbial cells are highly specific, fingerprint-like signatures which can be used to differentiate microbial species and strains from each other. In this study, the potential applicability of Fourier transform infrared (FTIR) spectroscopy for the classification of yeast strains in terms of their biological taxonomy, their use in the production of wine, beer, and bread, and their sensitivity to killer yeast strains was investigated. Sample preparation, spectral data preprocessing methods and spectral classification techniques were also investigated. All yeast strains were grown on a single growth medium. The FTIR spectra were baseline corrected and the second derivative spectra were computed and employed in spectral analysis. The classification accuracy was improved when the principal component spectra (calculated from the second derivative spectra) were employed rather than the second derivative spectra or raw spectra alone. Artificial neural network (ANN) with 10 units in the input layer and 12 units in the hidden layer produced a robust prediction model for the identification of yeasts. Cluster analysis was employed for the classification of yeast strains in terms of their use in the production of wine, beer, and bread and in terms of their sensitivity to killer yeast strains. The optimum region for the classification in the former case was found to be between 1300 and 800 cm-1 in the infrared spectrum whereas the optimum region for the classification of yeast strains in terms of their sensitivity was between 900 and 800 cm-1 . The results of this work demonstrated that FTIR spectroscopy could be successfully employed for the classification and identification of yeast strains with minimal sample preparation.
180

The sphecid wasps of southern Quebec (Hymenoptera: sphecidae).

Finnamore, Albert T. January 1979 (has links)
No description available.

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