Dissertations / Theses on the topic 'Optical information processing method'
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Братова, Дар'я Романівна. "Формування вейвлет вікон для фільтрації оптичної інформації." Master's thesis, КиЇв, 2019. https://ela.kpi.ua/handle/123456789/30424.
Full textThe dissertation is dedicated to developing a method for optical information processing. In engineering practice, different classes of transformation - Fourier, Laplace, etc. - are used to investigate the various signals of natural and artificial origin. Since the 1980s, wavelet transform (WF) has been predominantly used for frequency analysis of unsteady signals. Morle and Grossman were the first to do so, analyzing seismic data and coherent quantum states, respectively. The mathematical foundations of the WT were laid down by Meyer, who showed the existence of corresponding functions (wavelets) forming an orthogonal basis in the space L2 (R), that is, in the space of real functions whose square is integrated. Dobeshi made the transition from continuous to discrete WT and developed a class of wavelets that have maximum smoothness at a fixed length of their carrier. Currently, the scope of the WT is the approximation of functions and signals, their filtering and compression, searching for a signal of certain features, and more. The master's thesis consists of four sections. The first section analyzes the main advantages and disadvantages of wavelet and Fourier transforms and the features of their use. Examples of the main types of wavelets are also given. The second section provides a general classification of wavelets and each of them in general. In addition, the general characteristics of various wavelets and their calculation methods are considered. The third section is devoted to the development of a method of forming wavelet windows for filtering optical information. The third section presents the results of an analysis of the previous experimental works that show the possibility of creating synthesized digital nonlinear holograms as wavelet filters. The fourth section is devoted to the development of a startup project "Formation of wavelet windows for filtering optical information" and to analyze the prospects of entering the market from a marketing point of view.
ANDO, Hiroki, 大樹 安藤, Takeshi SAKAI, 猛. 酒井, Goro OBINATA, and 五郎 大日方. "磁気記録評価装置用変位拡大位置決め制御機構の機構形状とコントローラの統合化設計." 日本機械学会, 2006. http://hdl.handle.net/2237/8963.
Full textPotter, Duncan J. "Phase-only optical information processing." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/845.
Full textLe, Jeannic Hanna. "Optical Hybrid Quantum Information processing." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066596/document.
Full textIn quantum information science and technology, two traditionally-separated ways of encoding information coexist -the continuous and the discrete approaches, resulting from the wave-particle duality of light. The first one is based on quadrature components, while the second one involves single photons. The recent optical hybrid approach aims at using both discrete and continuous concepts and toolboxes to overcome the intrinsic limitations of each field. In this PhD work, first, we use hybrid protocols in order to realize the quantum state engineering of various non-Gaussian states of light. Based on optical parametric oscillators and highly-efficient superconducting-nanowire single-photon detectors, we demonstrate the realization of a high-brightness single-photon source and the quantum state engineering of large optical Schrödinger cat states, which can be used as a continuous-variable qubit. We show how continuous-variable operations such as squeezing can help in this generation. This method based on so-called core states also enables to generate cat states that are more robust to decoherence. Second, in the context of heterogeneous networks based on both encodings, bridging the two worlds by a quantum link requires hybrid entanglement of light. We introduce optical hybrid entanglement between qubits and qutrits of continuous and discrete types, and demonstrate as a first application the remote state preparation of continuous-variable qubits. Our experiment is also a versatile platform to study squeezing-induced micro-macro entanglement
Deng, Zhijie. "Novel optical devices for information processing." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5863.
Full textClark, Alex S. "Quantum information processing in optical fibres." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557975.
Full textSoutar, Colin. "Optical information processing using photorefractive BSO." Thesis, Abertay University, 1991. https://rke.abertay.ac.uk/en/studentTheses/a757b4d3-6c1e-4600-aed8-430e7078c6c5.
Full textTian, Kehan. "Three dimensional (3D) optical information processing." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35627.
Full textIncludes bibliographical references (p. 141-151).
Light exhibits dramatically different properties when it propagates in or interacts with 3D structured media. Comparing to 2D optical elements where the light interacts with a sequence of surfaces separated by free space, 3D optical elements provides more degrees of freedom to perform imaging and optical information processing functions. With sufficient dielectric contrast, a periodically structured medium may be capable of forbidding propagation of light in certain frequency range, called band gap; the medium is then called a photonic crystal. Various "defects", i.e. deviations from perfect periodicity, in photonic crystals are designed and widely used as waveguides and microcavities in integrated optical circuits without appreciable loss. However, many of the proposed waveguide structures suffer from large group velocity dispersion (GVD) and exhibit relatively small guiding bandwidth because of the distributed Bragg reflection (DBR) along the guiding direction. As optical communications and optical computing progress, more challenging demands have also been proposed, such as tunable guiding bandwidth, dramatically slowing down group velocity and active control of group velocity. We propose and analyze shear discontinuities as a new type of defect in photonic crystals.
(cont.) We demonstrate that this defect can support guided modes with very low GVD and maximum guiding bandwidth, provided that the shear shift equals half the lattice constant. A mode gap emerges when the shear shift is different than half the lattice constant, and the mode gap can be tuned by changing the amount of the shear shift. This property can be used to design photonic crystal waveguides with tunable guiding bandwidth and group velocity, and induce bound states. The necessary condition for the existence of guiding modes is discussed. By changing the shape of circular rods at the shear interface, we further optimize our sheared photonic crystals to achieve minimum GVD. Based on a coupled resonator optical waveguide (CROW) with a mechanically adjustable shear discontinuity, we also design a tunable slow light device to realize active control of the group velocity of light. Tuning ranges from arbitrarily small group velocity to approximately the value of group velocity in the bulk material with the same average refractive index. The properties of eigenstates of tunable CROWs: symmetry and field distribution, and the dependence of the group velocity on the shear shift are also investigated.
(cont.) Using the finite-difference time-domain (FDTD) simulation, we demonstrate the process of tuning group velocity of light in CROWs by only changing the shear shift. A weakly modulated 3D medium diffracts light in the Bragg regime (in contrast to Raman-Nath regime for 2D optical elements), called volume hologram. Because of Bragg selectivity, volume holograms have been widely used in data storage and 3D imaging. In data storage, the limited diffraction efficiency will affect the signal-noise-ratio (SNR), thus the memory capacity of volume holograms. Resonant holography can enhance the diffraction efficiency from a volume hologram by enclosing it in a Fabry-Perot cavity with the light multiple passes through the volume hologram. We analyze crosstalk in resonant holographic memories and derive the conditions where resonance improves storage quality. We also carry out the analysis for both plane wave and apodized Gaussian reference beams. By utilizing Hermite Gaussian references (higher order modes of Gaussian beams), a new holographic multiplexing method is proposed - mode multiplexing.
(cont.) We derive and analyze the diffraction pattern from mode multiplexing with Hermite Gaussian references, and predict its capability to eliminate the inter-page crosstalk due to the independence of Hermite Gaussian's orthogonality on the direction of signal beam as well as decrease intra-page crosstalk to lower level through apodization. When using volume holograms for imaging, the third dimension of volume holograms provided more degrees of freedom to shape the optical response corresponding to more demanding requirements than traditional optical systems. Based on Bragg diffraction, we propose a new technique - 3D measurement of deformation using volume holography. We derive the response of a volume grating to arbitrary deformations, using a perturbative approach. This result will be interesting for two applications: (a) when a deformation is undesirable and one seeks to minimize the diffracted field's sensitivity to it and (b) when the deformation itself is the quantity of interest, and the diffracted field is used as a probe into the deformed volume where the hologram was originally recorded.
(cont.) We show that our result is consistent with previous derivations motivated by the phenomenon of shrinkage in photopolymer holographic materials. We also present the analysis of the grating's response to deformation due to a point indenter and present experimental results consistent with theory.
by Kehan Tian.
Ph.D.
Davison, Alan Stephen. "All-optical signal processing devices." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316729.
Full textArain, Muzamil Arshad. "INTERFEROMETRY-BASED FREE SPACE COMMUNICATION AND INFORMATION PROCESSING." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3304.
Full textPh.D.
Optics and Photonics
Optics
Nicholas, Julian Jesuratnam. "Information processing in #parallel' visual pathways." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386633.
Full textAlic, Nikola. "Information processing for improved performance of optical networks." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3205498.
Full textTitle from first page of PDF file (viewed April 4, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 151-158).
Baker, Luke James. "Superconducting nanowire devices for optical quantum information processing." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/8440/.
Full textJacobo, Adrian. "Spatial structures and Information Processing in Nonlinear Optical Cavities." Doctoral thesis, Universitat de les Illes Balears, 2009. http://hdl.handle.net/10803/9436.
Full textNazir, Ahsan. "Optical schemes for quantum information processing in semiconductor nanostructures." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409819.
Full textKalasuwan, Pruet. "Optical quantum information processing in higher dimensional Hilbert space." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.573150.
Full textLowans, Brian Sinclair. "Applications of spatial light modulators in optical information processing." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282231.
Full textMiller, Paul Cecil. "Developments in optical information processing using spatial light modulators." Thesis, Queen's University Belfast, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336128.
Full textLord, Angus. "Localised states in nonlinear optical systems." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248315.
Full textKlein, Alexander. "Special purpose quantum information processing with atoms in optical lattices." Thesis, University of Oxford, 2007. http://ora.ox.ac.uk/objects/uuid:bc67ec3e-3cc7-4d13-ae11-b436b2ca897b.
Full textParedes-Barato, David. "Towards optical quantum information processing using Rydberg dark-state polaritons." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10889/.
Full textChaudhry, Mohammed Sabih. "Microwave I.F signal processing strategies for coherent optical communications." Thesis, Bangor University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357247.
Full textOtt, Melanie N. "Incoherent projection Moire contour sensing with coherent processing for large structures." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-08182009-040501/.
Full textLeibrandt, David R. "Integrated chips and optical cavities for trapped ion quantum information processing." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53229.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 145-158).
Quantum information processing is a new and exciting field which uses quantum mechanical systems to perform information processing. At the heart of the excitement are quantum computation - which promises efficient algorithms for simulating physical systems, factoring, and searching unsorted databases - and quantum communication - which provides a provably secure communications protocol. Trapped ions show much promise for achieving large-scale quantum information processing. Experiments thus far have demonstrated small algorithms and entanglement of two remote ions. Current work focuses on scaling to large numbers of ions for quantum computation and interconversion between trapped ions and photons for quantum communication. This thesis addresses some of the challenges facing scaling and interconversion for trapped ion quantum information processing. The first part of the thesis describes the development of scalable, multiplexed ion trap chips for quantum computation. The ion trap chips are based on a new ion trap geometry, called the surface-electrode trap, in which all of the electrodes reside in a single plane. Three generations of surface-electrode traps are designed, fabricated, and tested - culminating with the demonstration of an ion trap chip microfabricated using standard silicon VLSI materials and processes for scalability to small trap size and large arrays of interconnected ion traps. The second part of the thesis presents an experiment that demonstrates cavity cooling, a method of laser cooling the motional state of trapped ions without decohering the internal qubit state.
(cont.) Cavity cooling is demonstrated for the first time with trapped ions, and for the first time in the parameter regime where cooling to the motional ground state is possible. The measured cavity cooling dynamics are found to agree with a rate equation model without any free parameters. The third and final part of the thesis presents a theoretical proposal for interconversion between single trapped ion qubits and single photon qubits for quantum communication. The idea is to map the state of the single ion qubit to a superradiant collective state of several ions, which then couples strongly with single photons in an optical cavity.
by David R. Leibrandt.
Ph.D.
Qureshi, Faisal. "The nonlinear optical properties of conjugated molecular materials." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264642.
Full textRanshaw, M. J. "Phase-modulating spatial light modulators." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/14252.
Full textShi, H. (Henglin). "A GQM-based open research data technology evalution method in open research context." Master's thesis, University of Oulu, 2016. http://urn.fi/URN:NBN:fi:oulu-201605221853.
Full textKAIMAL, VINOD GOPALKRISHNA. "A NEURAL METHOD OF COMPUTING OPTICAL FLOW BASED ON GEOMETRIC CONSTRAINTS." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1037632137.
Full textHumphreys, Peter Conway. "Experimental and theoretical techniques for quantum-enhanced metrology and optical quantum information processing." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:57e942ac-f6f1-43fe-ac77-ef85b7db85ca.
Full textKauhanen, T. R. (Tiia-Riikka). "Designing a method for measuring the difficulty in kitchen tasks with people suffering from dementia." Master's thesis, University of Oulu, 2015. http://urn.fi/URN:NBN:fi:oulu-201510292098.
Full textHigashino, Satoru. "Study on signal processing and coding techniques for high density optical information storage channels." 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/135949.
Full textLau, Kai Kwong Gervas. "A new statistical stroke recovery method and measurement for signature verification." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/661.
Full textYu, Donggang, and dyu@venus it swin edu au. "Processing and recognition of document and GIS images." Swinburne University of Technology, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20050812.095914.
Full textKhan, Mughees Mahmood. "Fabrication and testing of nano-optical structures for advanced photonics and quantum information processing applications." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1165.
Full textКожухар, Павло Вікторович. "Кількісний контроль магнітних параметрів документів магнітооптичною телевізійною системою." Thesis, НТУУ «КПІ», 2016. https://ela.kpi.ua/handle/123456789/17695.
Full textThe magnetic control of documents (including banknotes and protected blanks) is used at its production, banking and forensic research. Present devices divide into two groups. First ones are using a stock of huge induction or Hall sensors and performing only quantitative magnetic control with low resolution. Second ones are using magneto-optic sensors, which allows doing qualitative magnetic control with high resolution but could not perform quantitative control due to low dynamic range. The dissertation covers developing of TV system intended for quantitative control of magnetic parameters of documents using magneto-optic sensor, which have not implemented. It allows increasing the accuracy of magnetic control of documents due to providing integrated (quantitative and qualitative) magnetic control with high resolution and using only one sensor. Developed generalized method of quantitative control of magnetic parameters of documents allows its classification with decreased effect of magneto-optic noise and sensitivity to changing of magnetization and print density. This method involves getting a two-dimensional distribution of the signal of scattered magnetic field of documents in matrix digital form perhaps improved method of magneto-optical topography with auxiliary magnetic field source and coprocessing of magneto-optic images by TV system. Thus, documents spatial distribution of magnetic flux density is obtained in suitable for digital automated signal processing form. The next steps are calculating histograms of magnetic field of reference and controlled documents; approximation and normalization of this histograms; pairwise comparison of normalized histograms by proposed qualitative index of dissimilarity and making check solution about a membership of controlled document at reference group. All these steps are performed automatically by TV system so the method allows decreasing expenditure of time during magnetic control of documents. In addition there is suggested the procedure of evaluating the sensitivity and resolution of the TV system for the magneto-optic check. It consist in SNR evaluation of magneto-optic image of test document sample with known signal and no-signal areas. A comprehensive experimental study of the theoretical developments is passed. Developed magneto-optical TV system allows detecting reprinting of document by another printer with accuracy 50 – 100% (for examined printing samples) at the expense of proposed qualitative control. There is proved for examined banknote samples a capability to detect a falsification of banknotes magnetic protection by developed system even if present (qualitative-only) magneto-optic detectors cannot detect falsification due to same topology of magnetic print. The sensitivity and resolution of developed TV system allows detection of magnetic paint strokes 21 μm width and resolution of strokes with width and spaced by 42 μm with SNR not less than 6 dB. Thus, developed methods allow to increase the accuracy of magnetic control (detection of falsification) of documents through the implementation of the quantitative control of their magnetic parameters, both for documents manufactured by industry (banknotes and protected forms) and made in publicly available way (print by office equipment). Herewith television systems implementing the method, retain the ability to qualitative documents research like topological and trasological, i. e. in contrast to known provide an integrated magnetic control of documents. That’s why scientific and practical results are implemented magneto-optic TV systems Regula 4197 and Regula 7701M, modern methodology of forensic research of magnetic print and digital help-desk system “Currensy”, which contains samples of magnetic parameters of world banknotes made by indicated above TV systems.
В диссертационной работе разработана магнитооптическая телевизионная система, которая в отличии от известных, позволяет помимо качественного выполнять количественный магнитный контроль документов. Разработан обобщенный метод количественного контроля магнитных параметров документов, который позволяет их классификацию со сниженным влиянием шумов магнитооптического преобразования, чувствительностью к изменению параметров намагничивания и неоднородностей плотности печати. Усовершенствован метод магнитооптического топографирования, что позволяет получать сигнал двумерного распределения рассеянного магнитного поля документов в матричной цифровой форме. Предложена методика оценки чувствительности и разрешающей способности телевизионной системы магнитооптического контроля. Проведено комплексное экспериментальное исследование теоретических наработок. Разработанные методы позволяют повысить достоверность магнитного контроля (выявления фальсификации) документов, как изготовленных промышленным методом (банкноты и защищенные бланки) так и общедоступным (печать бытовой оргтехникой) за счет выполнения количественного контроля их магнитных параметров. При этом телевизионные системы, реализующие предложенные методы, сохраняют возможность качественного топологического и трасологического исследования, т. е. в отличии от известных обеспечивают комплексный магнитный контроль документов.
Muldoon, Cecilia. "Control and manipulation of cold atoms in optical tweezers." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:920933c8-441c-4d59-a4f4-87f8c799a820.
Full textReed, Darren James. "Observing and quoting newsgroup messages : method and phenomenon in the hermeneutic spiral." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/6887.
Full textAiken, John Charles. "The development of a colour liquid crystal display spatial light modulator and applications in polychromatic optical data processing." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326384.
Full textLeedumrongwatthanakun, Saroch. "Quantum information processing with a multimode fibre." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS526.
Full textTransport of information through a multimode optical fibre raises challenges when one wants to increase the data traffic using many spatial modes due to modal cross-talk and dispersion. Instead of considering those complex mixing of modes as a detrimental process, in this dissertation, we harness its mode mixing to process quantum optical information. We implement a reconfigurable linear optical network, a fundamental building block for scalable quantum technologies, based on an inverse photonic approach exploiting the technology of wavefront shaping. We experimentally demonstrate manipulation of two-photon quantum interference on various linear optical networks across both spatial and polarization degrees of freedom. In particular, we experimentally show the zero-transmission law in Fourier and Sylvester interferometers, which are used to certificate the degree of indistinguishability of an input state. Moreover, thanks to the ability to implement a non-unitary network, we observe the photon anti-coalescence effect in all output configurations, as well as the realization of a tunable coherent absorption experiment. Therefore, we demonstrate the reconfigurability, accuracy, scalability and robustness of the implemented linear optical networks for quantum information processing. Furthermore, we study the statistical properties of one-and two-photon speckles generated from various ground-truth states of light after propagating through a multimode fibre. These statistical properties of speckles can be used to extract information about the dimensionality, purity, and indistinguishability of an unknown input state of light, therefore allowing for state classification. Our results highlight the potential of complex media combined with wavefront shaping for quantum information processing
Whitbread, P. J. "Multi-spectral texture : improving classification of multi-spectral images by the integration of spatial information /." Title page, abstract and contents only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phw5792.pdf.
Full textOne computer disk in pocket inside back cover. System requirements for accompanying computer disk: Macintosh computer. Includes bibliographical references (leaves 148-160).
Raguet, Hugo. "A Signal Processing Approach to Voltage-Sensitive Dye Optical Imaging." Thesis, Paris 9, 2014. http://www.theses.fr/2014PA090031/document.
Full textVoltage-sensitive dye optical imaging is a promising recording modality for the cortical activity, but its practical potential is limited by many artefacts and interferences in the acquisitions. Inspired by existing models in the literature, we propose a generative model of the signal, based on an additive mixtures of components, each one being constrained within an union of linear spaces, determined by its biophysical origin. Motivated by the resulting component separation problem, which is an underdetermined linear inverse problem, we develop: (1) convex, spatially structured regularizations, enforcing in particular sparsity on the solutions; (2) a new rst-order proximal algorithm for minimizing e›ciently the resulting functional; (3) statistical methods for automatic parameters selection, based on Stein’s unbiased risk estimate.We study thosemethods in a general framework, and discuss their potential applications in variouselds of applied mathematics, in particular for large scale inverse problems or regressions. We develop subsequently a soŸware for noisy component separation, in an integrated environment adapted to voltage-sensitive dye optical imaging. Finally, we evaluate this soŸware on dišerent data set, including synthetic and real data, showing encouraging perspectives for the observation of complex cortical dynamics
Allard, Christopher E. "Development of a non-destructive optical method to measure residual stress in thin rectangular samples employing digital image processing." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/20645.
Full textWEST, KAREN FRANCES. "AN EXTENSION TO THE ANALYSIS OF THE SHIFT-AND-ADD METHOD: THEORY AND SIMULATION (SPECKLE, ATMOSPHERIC TURBULENCE, IMAGE RESTORATION)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188021.
Full textWang, Zhao. "Intravascular Optical Coherence Tomography Image Analysis." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1364673682.
Full textHrůza, Libor. "Koherentní analogové zpracování optické informace." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217466.
Full textWingen, Georg. "Vertikale Wanderwellenmodulatoren auf Quantenfilmbasis für die optische Informationsverarbeitung - Vertical travelling-wave modulators using quantum-well material for optical information processing." Gerhard-Mercator-Universitaet Duisburg, 2001. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-10122001-113233/.
Full textAlonso, Miguel Jr. "A method for enhancing digital information displayed to computer users with visual refractive errors via spatial and spectral processing." FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/1112.
Full textRundin, Patrick. "Evaluation of a statistical method to use prior information in the estimation of combustion parameters." Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6255.
Full textIon current sensing, where information about the combustion process in an SI-engine is gained by applying a voltage over the spark gap, is currently used to detect and avoid knock and misfire. Several researchers have pointed out that information on peak pressure location and air/fuel ratio can be gained from the ion current and have suggested several ways to estimate these parameters.
Here a simplified Bayesian approach was taken to construct a lowpass-like filter or estimator that makes use of prior information to improve estimates in crucial areas. The algorithm is computationally light and could, if successful, improve estimates enough for production use.
The filter was implemented in several variants and evaluated in a number of simulated cases. It was found that the proposed filter requires a number of trade-offs between variance, bias, tracking speed and accuracy that are difficult to balance. For satisfactory estimates and trade-off balance the prior information must be more accurate than was available.
It was also found that similar a task, constructing a general Bayesian estimator, has already been tackled in the area of particle filtering and that there are promising and unexplored possibilities there. However, particle filters require computational power that will not be available to production engines for some years.
Vid jonströmsmätning utvinns information om förbränningsprocessen i en bensinmotor genom att en spänning läggs över gnistgapet och den resulterande strömmen mäts. Jonströmsmätning används idag för knack- och feltändningsdetektion. Flera forskare har påpekat att det finns än mer information i jonströmmen, bl.a. om bränsleblandningen och cylindertrycket och har även föreslagit metoder för att utvinna och använda den informationen för skattning av dessa parametrar.
Här presenteras en förenklad Bayesisk metod i form av en lågpassfilter-liknande skattare som använder förkunskap till att förbättra estimat på relevanta områden. Algoritmen är beräkningsmässigt lätt och kan, om den är framgångsrik, leverera skattningar av förbränningsparametrar som är tillräckligt bra för att användas för sluten styrning av en bensinmotor.
Skattaren, eller filtret, implementerades i flera varianter och utvärderades i ett antal simulerade fall. Resultaten visade på att flera svåra avvägningar måste göras mellan förbättring i varians, avvikelse och följning eftersom förbättring i den ena ledde till försämring i de andra. För att göra dessa avvägningar och få goda skattningar krävs bättre förhandskunskap och mätdata än vad som var tillgängligt.
Bayesisk skattning är ett stort befintligt område inom statistik och signalbehandling och den mest generella skattaren är partikelfiltret som har många intressanta tillämpningar och möjligheter. De har hittills inte använts inom skattning av förbränningsparametrar och har således go potential för framtida utveckling. De är dock beräkningsmässigt tunga och kräver beräkningsresurser utöver vad som är tillgängliga i ett motorstyrsystem idag.
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