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Odelade, Mobolaji. "P300 Control Matrix| A Novel Approach to P300 Speller Matrix." Thesis, North Carolina Agricultural and Technical State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10976563.
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Over the years, researchers have been able to prove Brain Computer Interface (BCI) -P300 Speller as an effective communication tool. The first P300 speller was developed by Farwell and Donchin (1988), using the oddball paradigm to evoke a P300 response from a speller matrix. This P300 speller matrix has been a strong basis for studies that aimed at using BCI-P300 protocol for spelling, cursor movement, internet navigation or even control and manipulation of devices. However, application of P300 based BCI to controlling and manipulation of devices often involves the user relating with multiple interfaces. These multiple interfaces could be a distraction or have negative effects on the user (Fazel-Rezai et al. 2012) and as a consequence hinders the evoking of P300 potential and causing inaccurate classification. For this research, a novel P300 control matrix is developed by replacing the alphabets in the traditional P300 speller matrix with arrow images. Then the novel P300 control matrix was investigated to compare the P300 latency and amplitude to that of the traditional P300 speller matrix. The elements in the novel P300 control matrix were in form of arrows facing upward, left, right and downward directions, while elements in the P300 speller matrix were alphabets U, L, R and D for the upward, left, right and downward directions respectively. The participants were presented with a set of randomly sequenced directions, and each participant decides which of the arrows or letters to focus on based on the direction presented to them. Electroencephalography (EEG) was used to record the brainwaves using the international 10-20 system of electrode placement. This research is potentially a more efficient approach for controlling devices using P300-based BCI systems by eradicating the need for multiple interfaces associated with BCI-robotic control systems that are based on P300 speller.
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Xu, Genjiu. "Matrix approach to cooperative game theory." Enschede : University of Twente [Host], 2008. http://doc.utwente.nl/59410.
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Hyder, Kieran. "Barnacle demography : a matrix modelling approach." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285626.
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Lambert, William. "Matrix approach for ultrasound imaging and quantification." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLS028.
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L’échographie est basée sur deux hypothèses fondamentales. D’une part, la vitesse du son est considérée comme constante dans le milieu de propagation. D’autre part, les échos rétrodiffusés par les diffuseurs du milieu sont issus de phénomènes de diffusion simple. En réalité, ces hypothèses ne sont pas toujours vérifiées : des variations de vitesse du son entre les différents tissus sondés peuvent induire de fortes distorsions du front d'onde (aberrations) et des évènements de diffusion multiple peuvent survenir entre les réflecteurs du milieu. Ces deux phénomènes indésirables conduisent à une perte de résolution et de contraste de l’image échographique.En échographie conventionnelle, les ondes ultrasonores sont générées et mesurées depuis un réseau de transducteurs piézo-électriques dont on peut contrôler de manière indépendante chacun des éléments. L’image échographique résulte d’une double focalisation simultanée, en entrée et sortie, des ondes ultrasonores en chaque point du milieu à imager. L’échographie matricielle, mise au point au cours de cette thèse, consiste au contraire à séparer les points de focalisation à l’émission et à la réception et ainsi mesurer les réponses du milieu entre ces transducteurs virtuels dont la position correspond à chaque pixel de l’image. L’ensemble de ces réponses forment une matrice de réflexion focalisée. A partir de cette matrice, une nouvelle approche de l’imagerie ultrasonore a été développée afin de tirer profit de toute l’information disponible sur le milieu étudié. En plus de pouvoir décrire sous un formalisme matriciel l’ensemble des techniques d’imagerie ultrasonore actuelles, l’imagerie matricielle a été développée en poursuivant plusieurs objectifs : (i) Améliorer et quantifier la qualité des images échographiques en corrigeant de manière locale les aberrations ; (ii) Caractériser localement le milieu de propagation en dressant une cartographie de sa vitesse du son et du taux de diffusion multiple ; (iii) Caractériser localement la nature et l’anisotropie des diffuseurs en étudiant leur réponse spectrale et leur diagramme de rayonnement.Ce travail s’inscrit dans un cadre plus large dont l’objectif est de développer une approche matricielle de l’imagerie commune à tous les domaines de la physique des ondes pour lesquels un ensemble de capteurs peuvent être utilisés pour sonder le milieu à imager. Ce manuscrit décrit le développement de cette imagerie matricielle dans le contexte ultrasonore avec l’élaboration de nouveaux contrastes permettant une imagerie quantitative des tissus sondés en échographieUltrasound imaging relies on two major assumptions. First, the medium is considered as homogeneous with a constant speed of sound. Second, the back-scattered wave-field only contains singly-scattered echoes. Nonetheless, the speed of sound varies greatly in different tissues. These fluctuations give rise to a distortion of the incident and back-scattered wave-fronts. Moreover, multiple scattering events can also occur between the scatterers of the medium. This multiple scattering contribution manifests itself as an incoherent background noise in the RF signal. Those two undesirable effects, namely aberrations and multiple scattering, thus lead to a loss of resolution and contrast in the ultrasound image.Conventional ultrasound imaging techniques rely on arrays of transducers that can be individually controlled to emit or receive ultrasonic waves. State-of-the-art ultrasound images are based on a confocal method that consists in a double focusing, both in transmit and in receive, on each point of the medium corresponding to one pixel of the image. In this thesis, we propose a matrix approach of ultrasound imaging that basically consists in splitting the locations of the transmit and receive focal spots. This process gives access to the impulse responses between virtual transducers located within the medium at each pixel location. This set of responses form a so-called focused reflection matrix that contains all the available information on the medium under investigation. Besides describing all the current ultrasound imaging methods under a matrix formalism, matrix imaging is able to take up several challenges: (i) quantify and enhance the ultrasound image quality via a local focusing criterion and a matrix aberration correction; (ii) develop novel quantitative imaging modes by building maps of the speed-of-sound and of a multiple-scattering-rate that may constitute relevant biomarkers for ultrasound diagnosis; (iii) characterize locally the nature and anisotropy of the scatterers via their frequency response and radiation pattern.More generally, this work falls into a larger framework, which aims to develop a universal matrix approach that can be applied to any type of waves where multiple sensors can be used to shape incident wave-fronts and analyze reflected ones. This thesis describes this matrix approach in the ultrasound imaging context and paves the way towards a quantitative ultrasound imaging of soft tissues
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Puerta, David Thomas. "A bioinorganic approach to matrix metalloproteinase inhibition." 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?p3202706.
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Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed March 1, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references ( p. 214-216).
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Dionigi, Pierfrancesco. "A random matrix theory approach to complex networks." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18513/.
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Si presenta un approccio matematico formale ai complex networks tramite l'uso della Random Matrix Theory (RMT). La legge del semicerchio di Wigner viene presentata come una generalizzazione del Teorema del Limite Centrale per determinati ensemble di matrici random. Sono presentati inoltre i principali metodi per calcolare la distribuzione spettrale delle matrici random e se ne sottolineano le differenze. Si è poi studiato come la RMT sia collegata alla Free Probability. Si è studiato come due tipi di grafi random apparentemente uguali, posseggono proprietà spettrali differenti analizzando le loro matrici di adiacenza. Da questa analisi si deducono alcune proprietà geometriche e topologiche dei grafi e si può analizzare la correlazione statistica tra i vertici. Si è poi costruito sul grafo un passeggiata aleatoria tramite catene di Markov, definendo la matrice di transizione del processo tramite la matrice di adiacenza del network opportunamente normalizzata. Infine si è mostrato come il comportamento dinamico della passeggiata aleatoria sia profondamente connesso con gli autovalori della matrice di transizione, e le principali relazioni sono mostrate.
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Gani, Sohail M. "A gate matrix approach to VLSI logic layout." Thesis, University of Essex, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238380.
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Sutton, Brian D. (Brian David). "The stochastic operator approach to random matrix theory." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33094.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2005.Includes bibliographical references (p. 147-150) and index.
Classical random matrix models are formed from dense matrices with Gaussian entries. Their eigenvalues have features that have been observed in combinatorics, statistical mechanics, quantum mechanics, and even the zeros of the Riemann zeta function. However, their eigenvectors are Haar-distributed-completely random. Therefore, these classical random matrices are rarely considered as operators. The stochastic operator approach to random matrix theory, introduced here, shows that it is actually quite natural and quite useful to view random matrices as random operators. The first step is to perform a change of basis, replacing the traditional Gaussian random matrix models by carefully chosen distributions on structured, e.g., tridiagonal, matrices. These structured random matrix models were introduced by Dumitriu and Edelman, and of course have the same eigenvalue distributions as the classical models, since they are equivalent up to similarity transformation. This dissertation shows that these structured random matrix models, appropriately rescaled, are finite difference approximations to stochastic differential operators. Specifically, as the size of one of these matrices approaches infinity, it looks more and more like an operator constructed from either the Airy operator, ..., or one of the Bessel operators, ..., plus noise. One of the major advantages to the stochastic operator approach is a new method for working in "general [beta] " random matrix theory. In the stochastic operator approach, there is always a parameter [beta] which is inversely proportional to the variance of the noise.
(cont.) In contrast, the traditional Gaussian random matrix models identify the parameter [beta] with the real dimension of the division algebra of elements, limiting much study to the cases [beta] = 1 (real entries), [beta] = 2 (complex entries), and [beta] = 4 (quaternion entries). An application to general [beta] random matrix theory is presented, specifically regarding the universal largest eigenvalue distributions. In the cases [beta] = 1, 2, 4, Tracy and Widom derived exact formulas for these distributions. However, little is known about the general [beta] case. In this dissertation, the stochastic operator approach is used to derive a new asymptotic expansion for the mean, valid near [beta] = [infinity]. The expression is built from the eigendecomposition of the Airy operator, suggesting the intrinsic role of differential operators. This dissertation also introduces a new matrix model for the Jacobi ensemble, solving a problem posed by Dumitriu and Edelman, and enabling the extension of the stochastic operator approach to the Jacobi case.
by Brian D. Sutton.
Ph.D.
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Grey, Clive. "Post 1998 cross functional/matrix approach to management." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/4920.
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Thesis (MBA (Business Management))--University of Stellenbosch, 2005.ENGLISH ABSTRACT: The matrix structure has had varying degrees of success over the last 35 years. During this period the major factors, seen as critical to achieving matrix effectiveness, have been identified as: • communication; • strong leader; • culture; • rewards; • skills in teams; • clear and defined goals; • senior management support; • defined responsibility; • accountability; and • procedures and standards. A matrix structure (In the form of Category Management) was introduced into our organisation (USABCO) in 1999 and three years later it was replaced with the previous structure (Hierarchical Structure). In hind light the category management structure, if implemented correctly with the relevant preparation, training, and support,would have improved new product development efficiency. Eleven recent articles related to matrix effectiveness were selected and analysed, and the results used to establish the following for each of the above and other critical factors: • proposed actions that can be taken to improve matrix effectiveness; and • reported benefits of these actions. This is not an exhaustive list but rather a summary of results from current research, empirical studies and surveys.
AFRIKAANSE OPSOMMING: Die matriks struktuur het oor die laaste 35 jaar verskillende suksesse behaal. Gedurende hierdie periode, was die volgende hoof faktore gesien as krities tot die bereiking van matriks doeltreffendheid: • kommunikasie; • sterk leiers; • kultuur; • vergoeding; • vaardighede in spanne; • duidelike doelwitte; • bemagtiging van lede; • senior bestuur ondersteuning; • gedefinieerde verantwoordlikheid; • toerekenbaarheid; en • prosedures en standaarde. Die matriks struktuur (in die vorm van kategoriebestuur) was in 1999 in ons maatskappy bekend gestel en na 3 jaar was dit weer vervang met die vorige struktuur (hierargiese struktuur). Die "kategorie bestuur struktuur" kon nuwe produk ontwikkeling doeltreffendheid verbeter, as dit reg geimplementeer was met die nodige voorbereiding, opleiding en ondersteuning. Elf onlangse artikels, wat verband hou met matriks doeltreffendheid, was geselekteer en geanaliseer en die resultate gebruik om die volgende vas te stel vir elkeen van die bogenoemde hooffaktore: • voorgestelde aksies om matriks doeltreffendheid te verbeter; en • gepubliseerde voordele van die aksies. Dit is nie 'n volledige lys nie, maar eerder 'n opsomming van huidige navorsing, empiriese studies en ondersoeke.
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Gan, H. H. "Aroma-matrix interaction in food : an APCI approach." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29071/.
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An overview is presented of the principle, scope and major applications to date of the use of atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) for monitoring the kinetics of release of flavour volatiles in real time. There are four major areas in this thesis that extend from the measurement of flavour molecular mobility in sugar solutions, to the investigation of APCI-MS as a diagnostic tool for classifying apple cultivars and predicting age of cheese. Headspace techniques are the most extensively employed techniques in food analysis to measure volatile compounds, which play a central role in the perceived quality of food. The use of APCI-MS to measure aroma headspace availability with the addition of solutes was evaluated for two sugars of differing chain lengths (fructose and fructooligosaccharide (FOS)). In vitro aroma release was investigated at equilibrium using APCI-MS. An increase in the concentration of fructose above 25 % (w /w) was shown to significantly (p < 0.05) increase the release of ethyl butyrate, ethyl acetate and benzaldehyde into the gas phase above the aqueous solutions. Proton nuclear magnetic resonance (1 H NMR) was used to investigate the nature of solvent-sugar-aroma interactions with a view to explain the differential availability of aroma volatiles in sweetened and biopolymer rich solutions. The T1 relaxation times, and diffusion coefficients, provided preliminary clues as to the interactions between water, aroma and biopolymer. In the case of in vivo measurement, aroma perception was dependent on two key factors – firstly the equilibrium gas phase concentration of the aroma compounds within the oral/ nasal cavity and secondly the dynamic interaction of the compound with food and saliva (persistence). The overall process was influenced by the properties of the flavour compounds (i.e. its hydrophobicity) and the physiological conditions of the mouth, nose and throat during consumption of the food. A comparison was made between the intensities of anisaldehyde, furaneol and guaiacol in the headspace above simple solutions of water, to demonstrate the impact of matrix on flavour release in a frozen dairy dessert. The oral and nasal persistence of aromas following swallowing samples of a model frozen dairy dessert was investigated by collecting expired air from nose and mouth over 60-seconds. The decay curves (which illustrates persistence) of volatiles in breath showed that furaneol was the most persistent aroma, due to its hydrophilic nature and low volatility, that is expressed by the vapour pressure values of the pure compound. It is presumed to interact with the nasal mucosa, thereby prolonging persistence and potentially offering a significantly different perceptual profile to the less persistent compounds (Hodgson, Parker, Linforth, & Taylor, 2004). Thus, real time APCI-MS headspace data could be used to validate mathematical modelling of flavour release (Harvey & Barra, 2003). The feasibility of APCI-MS volatile compound fingerprinting in conjunction with chemometrics as a new strategy for rapid and non-destructive food classification was demonstrated when 202 clarified monovarietal juices extracted from apples differing in their botanical and geographical origins were characterised. Partial Least Square-Linear Discriminant Analysis (PLS-LDA) gave 100 % correct classification for the categorization by cultivar. Another PLS regression model was built to interpret and predict the age of Cheddar using headspace data from GC-MS and APCI-MS. The RMSEP and R2 values for the prediction model were 3.94 and 0.85 respectively. This further established the applicability of multivariate statistical technique as a tool to monitor the quality of foodstuff. Throughout the thesis, recommendations regarding practical implications for APCI-MS analysis and applications are demonstrated and discussed.
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Al-Mudhaf, Ali F. "A feed forward neural network approach for matrix computations." Thesis, Brunel University, 2001. http://bura.brunel.ac.uk/handle/2438/5010.
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A new neural network approach for performing matrix computations is presented. The idea of this approach is to construct a feed-forward neural network (FNN) and then train it by matching a desired set of patterns. The solution of the problem is the converged weight of the FNN. Accordingly, unlike the conventional FNN research that concentrates on external properties (mappings) of the networks, this study concentrates on the internal properties (weights) of the network. The present network is linear and its weights are usually strongly constrained; hence, complicated overlapped network needs to be construct. It should be noticed, however, that the present approach depends highly on the training algorithm of the FNN. Unfortunately, the available training methods; such as, the original Back-propagation (BP) algorithm, encounter many deficiencies when applied to matrix algebra problems; e. g., slow convergence due to improper choice of learning rates (LR). Thus, this study will focus on the development of new efficient and accurate FNN training methods. One improvement suggested to alleviate the problem of LR choice is the use of a line search with steepest descent method; namely, bracketing with golden section method. This provides an optimal LR as training progresses. Another improvement proposed in this study is the use of conjugate gradient (CG) methods to speed up the training process of the neural network. The computational feasibility of these methods is assessed on two matrix problems; namely, the LU-decomposition of both band and square ill-conditioned unsymmetric matrices and the inversion of square ill-conditioned unsymmetric matrices. In this study, two performance indexes have been considered; namely, learning speed and convergence accuracy. Extensive computer simulations have been carried out using the following training methods: steepest descent with line search (SDLS) method, conventional back propagation (BP) algorithm, and conjugate gradient (CG) methods; specifically, Fletcher Reeves conjugate gradient (CGFR) method and Polak Ribiere conjugate gradient (CGPR) method. The performance comparisons between these minimization methods have demonstrated that the CG training methods give better convergence accuracy and are by far the superior with respect to learning time; they offer speed-ups of anything between 3 and 4 over SDLS depending on the severity of the error goal chosen and the size of the problem. Furthermore, when using Powell's restart criteria with the CG methods, the problem of wrong convergence directions usually encountered in pure CG learning methods is alleviated. In general, CG methods with restarts have shown the best performance among all other methods in training the FNN for LU-decomposition and matrix inversion. Consequently, it is concluded that CG methods are good candidates for training FNN of matrix computations, in particular, Polak-Ribidre conjugate gradient method with Powell's restart criteria.
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Timms, Paul Martin. "A Bayesian approach to origin-destination trip matrix estimation." Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257965.
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Sthapit, Akshay R. (Akshay Ratna) 1978. "An object oriented approach to matrix analysis of structures." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/84810.
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Qambar, Sami Ali. "A systems approach to construction productivity." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312207.
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Möri-Wymann, Andreas. ""In situ" matrix diffusion in crystalline rocks : an experimental approach /." Bern : [s.n.], 2009. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Befekadu, Getachew Kebede. "Robust decentralized control of power systems a matrix inequalities approach /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980940893.
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Mitchell, David G. M. "Mathematical approach to channel codes with a diagonal matrix structure." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4330.
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Digital communications have now become a fundamental part of modern society. In communications, channel coding is an effective way to reduce the information rate down to channel capacity so that the information can be transmitted reliably through the channel. This thesis is devoted to studying the mathematical theory and analysis of channel codes that possess a useful diagonal structure in the parity-check and generator matrices. The first aspect of these codes that is studied is the ability to describe the parity-check matrix of a code with sliding diagonal structure using polynomials. Using this framework, an efficient new method is proposed to obtain a generator matrix G from certain types of parity-check matrices with a so-called defective cyclic block structure. By the nature of this method, G can also be completely described by a polynomial, which leads to efficient encoder design using shift registers. In addition, there is no need for the matrices to be in systematic form, thus avoiding the need for Gaussian elimination. Following this work, we proceed to explore some of the properties of diagonally structured lowdensity parity-check (LDPC) convolutional codes. LDPC convolutional codes have been shown to be capable of achieving the same capacity-approaching performance as LDPC block codes with iterative message-passing decoding. The first crucial property studied is the minimum free distance of LDPC convolutional code ensembles, an important parameter contributing to the error-correcting capability of the code. Here, asymptotic methods are used to form lower bounds on the ratio of the free distance to constraint length for several ensembles of asymptotically good, protograph-based LDPC convolutional codes. Further, it is shown that this ratio of free distance to constraint length for such LDPC convolutional codes exceeds the ratio of minimum distance to block length for corresponding LDPC block codes. Another interesting property of these codes is the way in which the structure affects the performance in the infamous error floor (which occurs at high signal to noise ratio) of the bit error rate curve. It has been suggested that “near-codewords” may be a significant factor affecting decoding failures of LDPC codes over an additive white Gaussian noise (AWGN) channel. A near-codeword is a sequence that satisfies almost all of the check equations. These nearcodewords can be associated with so-called ‘trapping sets’ that exist in the Tanner graph of a code. In the final major contribution of the thesis, trapping sets of protograph-based LDPC convolutional codes are analysed. Here, asymptotic methods are used to calculate a lower bound for the trapping set growth rates for several ensembles of asymptotically good protograph-based LDPC convolutional codes. This value can be used to predict where the error floor will occur for these codes under iterative message-passing decoding.
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CristoÌbal, Arturo Molina. "Multiobjective control : linear matrix inequalities techniques and genetic algorithms approach." Thesis, University of Sheffield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419615.
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Di, Ciò Stefania. "How cells sense the matrix geometry : a novel nanopatterning approach." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/31789.
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Tissue engineering and regenerative medicine aim to develop materials that mimic some of the characteristics of the tissue they are replacing and control the growth and proliferation of cells. Despite exceptional advances in the range and quality of materials used, much remains to discover about the processes regulating interfaces between cells and their surroundings, or at cell-material interfaces. In order to study and control such interactions, scientists have produced engineered matrices aiming to mimic some of the feature of natural extra-cellular matrix (biochemistry, geometry/topography and mechanical properties). In order to pattern 2D-nanofibers on relatively large areas and throughput, allowing comprehensive biological studies, we developed a nano-fabrication technique based on the deposition of sparse mats of electrospun fibres with different diameters. These mats are used as masks to grow cell resistant polymer brushes from exposed areas. After removal of the fibres, the remaining brushes define a quasi-2D fibrous pattern onto which ECM molecules such as fibronectin can be adsorbed. Chapter 2 includes details of the techniques used to produce and characterize the fibrous nanopattern. Chapter 3 is focused on cell phenotype observed on the different nanofibres sizes. Adhesion assays showed that cell spreading, shape and polarity are regulated by the size of fibres but also the density of the nanofibres, similarly to previous observations made on circular nanopatterns. We then focused on the study of focal adhesion formation and maturations on these nanofibres and the role of key proteins involved in the regulation of the adhesion plaque: integrins and vinculin. Cells expressing different integrins were found to sense the nanoscale geometry differently. Vinculin sensing is the topic of Chapter 4. Although vinculin recruitment dynamics was affected by the nanofibrous patterns and focal adhesions arrange differently on the nanofibres, this protein does not seem to mediate nanoscale sensing. In Chapter 5, we finally focused on the role of the actin cytoskeleton as a direct sensor of nanoscale geometry. A gradual decrease in stress fibre formation was observed as the nanofibres dimensions decrease. Live imaging also demonstrated that the geometry of the extracellular environment strongly affects cytoskeleton rearrangement, stress fibres formation and disassembly. We identify the role of cytoskeleton contractility as an important sensor of the nanoscale geometry. Our study provides a deeper insight in understanding cell adhesion to the extracellular environment and the role of the matrix geometry and topography on such phenomena, but also raises questions regarding the more detailed molecular sensory elements enabling the direct sensing of nanoscale geometry through the actin cytoskeleton.
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Mahmud, Rashad Hassan. "Synthesis of waveguide antenna arrays using the coupling matrix approach." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6564/.
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With the rapid development in communication systems recently, improvements in components of the systems such as antennas and bandpass filters are continuously required to provide improved performance. High gain, wide bandwidth, and small size are the properties of antennas which are demanded in many modern applications, and achieving these simultaneously is a challenge. This thesis presents a new design approach to address this challenge. The coupling matrix is an approach used to represent the circuits made of coupled resonators such as filters and multiplexers. The approach has been utilised here to integrate a single resonator-based antenna with an n\(^t\)\(^h\) order filter. The integrated component is capable of providing a controllable bandwidth and introduces the filtering functionality. The approach is further developed in order to integrate bandpass filters with N×N resonator-based antenna arrays. This is to increase the gain of the array as well. Six novel components have been fabricated for the purpose of validation. This thesis also looks at a 300 GHz communication system which is proposed at The University of Birmingham with the objective to build a 10 metre indoor communication link. A 300 GHz (8×8) waveguide antenna array has been designed and fabricated for the system.
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Giscard, Pierre-Louis. "A graph theoretic approach to matrix functions and quantum dynamics." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:ceef15b0-eed2-4615-a9f2-f9efbef470c9.
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Many problems in applied mathematics and physics are formulated most naturally in terms of matrices, and can be solved by computing functions of these matrices. For example, in quantum mechanics, the coherent dynamics of physical systems is described by the matrix exponential of their Hamiltonian. In state of the art experiments, one can now observe such unitary evolution of many-body systems, which is of fundamental interest in the study of many-body quantum phenomena. On the other hand the theoretical simulation of such non-equilibrium many-body dynamics is very challenging. In this thesis, we develop a symbolic approach to matrix functions and quantum dynamics based on a novel algebraic structure we identify for sets of walks on graphs. We begin by establishing the graph theoretic equivalent to the fundamental theorem of arithmetic: all the walks on any finite digraph uniquely factorise into products of prime elements. These are the simple paths and simple cycles, walks forbidden from visiting any vertex more than once. We give an algorithm that efficiently factorises individual walks and obtain a recursive formula to factorise sets of walks. This yields a universal continued fraction representation for the formal series of all walks on digraphs. It only involves simple paths and simple cycles and is thus called a path-sum. In the second part, we recast matrix functions into path-sums. We present explicit results for a matrix raised to a complex power, the matrix exponential, matrix inverse, and matrix logarithm. We introduce generalised matrix powers which extend desirable properties of the Drazin inverse to all powers of a matrix. In the third part, we derive an intermediary form of path-sum, called walk-sum, relying solely on physical considerations. Walk-sum describes the dynamics of a quantum system as resulting from the coherent superposition of its histories, a discrete analogue to the Feynman path-integrals. Using walk-sum we simulate the dynamics of quantum random walks and of Rydberg-excited Mott insulators. Using path-sum, we demonstrate many-body Anderson localisation in an interacting disordered spin system. We give two observable signatures of this phenomenon: localisation of the system magnetisation and of the linear magnetic response function. Lastly we return to the study of sets of walks. We show that one can construct as many representations of series of walks as there are ways to define a walk product such that the factorisation of a walk always exist and is unique. Illustrating this result we briefly present three further methods to evaluate functions of matrices. Regardless of the method used, we show that graphs are uniquely characterised, up to an isomorphism, by the prime walks they sustain.
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Myshlyavtsev, Alexander V., and Marta D. Myshlyavtseva. "Modeling of surface diffusion for stepped surfaces: transfer matrix approach." Diffusion fundamentals 6 (2007) 27, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14201.
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Veras, Richard Michael. "A Systematic Approach for Obtaining Performance on Matrix-Like Operations." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1011.
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Scientific Computation provides a critical role in the scientific process because it allows us ask complex queries and test predictions that would otherwise be unfeasible to perform experimentally. Because of its power, Scientific Computing has helped drive advances in many fields ranging from Engineering and Physics to Biology and Sociology to Economics and Drug Development and even to Machine Learning and Artificial Intelligence. Common among these domains is the desire for timely computational results, thus a considerable amount of human expert effort is spent towards obtaining performance for these scientific codes. However, this is no easy task because each of these domains present their own unique set of challenges to software developers, such as domain specific operations, structurally complex data and ever-growing datasets. Compounding these problems are the myriads of constantly changing, complex and unique hardware platforms that an expert must target. Unfortunately, an expert is typically forced to reproduce their effort across multiple problem domains and hardware platforms. In this thesis, we demonstrate the automatic generation of expert level high-performance scientific codes for Dense Linear Algebra (DLA), Structured Mesh (Stencil), Sparse Linear Algebra and Graph Analytic. In particular, this thesis seeks to address the issue of obtaining performance on many complex platforms for a certain class of matrix-like operations that span across many scientific, engineering and social fields. We do this by automating a method used for obtaining high performance in DLA and extending it to structured, sparse and scale-free domains. We argue that it is through the use of the underlying structure found in the data from these domains that enables this process. Thus, obtaining performance for most operations does not occur in isolation of the data being operated on, but instead depends significantly on the structure of the data.
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Wang, Biying. "3D matrix-based visualization system of association rules." Thesis, Mittuniversitetet, Avdelningen för informations- och kommunikationssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-29344.
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With the growing number of association rules, it becomes moreand more difficult for users to explore interesting rules due toits nature complexity. Studies base on human perception andintuition show that graphical representation could be a betterillustration of how to handle data by using the capabilities ofthe human visual system to seek information. The 3D matrixbasedapproach visualization system of association rules called3DMVS was implemented in present study. The main visualrepresentation employed the extended matrix-based approachwith rule-to-items mapping to general transaction data set. Anovel method merging rules and assigning weight is proposedto generate new rules to reduce the dimension of theassociation rules, which will help users to find more importantitems in the new rule. Additionally, several interactions suchas sorting, filtering, zoom and rotation, facilitate decisionmakers to explore the rules they are interested in variousaspects. Finally, various evaluation techniques have beenemployed to assess the system from a logical reasoning pointof view.
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Afa, Iduabo John. "Ultrafast quantum control of atoms and molecules : a density matrix approach." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/461386.
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Control is important for transferring theoretical scientific knowledge into practical technology for applications in numerous fields. This is why coherent control study is significant on every timescale to have a complete understanding of dynamic processes that occur on the electron, atomic and molecular levels. As a result, numerous schemes have been proposed to carry out effective quantum control of diverse systems and study the dynamics of these systems based on their natural timescales from the picoseconds (10-12 s), femtosecond (10-15 s) to attosecond (10-18 s) regimes. The goals of these various studies depend on the desired application, for instance in Photochemistry a long standing objective is achieving selective population transfer from an initial state to a desired target state with little or no diminution in the energy transferred. In quantum computation, a central issue is the excitation of unoccupied Rydberg states with numerous proposals for its use in the design and implementation of robust fast quantum gates. Also, since the advent of the generation of attosecond XUV pulses, doors have been opened for achieving control of atomic-scale electron dynamics and observing them in real-time.
This thesis explores the modelling of dynamical light-matter interaction processes, like effective population inversion and generation of vibrational coherences in atoms and molecules, on their fundamental timescales using the density matrix (DM) theory under and beyond the rotating wave approximation (RWA). The thesis begins by introducing the concept of coherent control of simple quantum systems based on the DM formalism and expands the application to a more complex Oxazine system. Multiphoton p-pulse scheme is demonstrated for the control of population transfer in multilevel systems, for example with a trichromatic p-pulse having a set of areas v3 p, 2p and v3 p, complete population transfer in a four level system can be achieved. The aforementioned scheme is used to achieve effective control of low-lying Rydberg states in rubidium atoms, demonstrating how the effective control can be crucially affected by numerous physical processes. One main advantage of the density matrix approach over other theoretical approaches is that it allows the possibility of easily computing relaxation terms and other physical parameters critical to successful coherent control. The DM formalism is shown to be successful in properly describing the enhancement effects in atoms and complex molecular systems. It is robust in coherent control and quantum control spectroscopy (QCS) schemes and is extendable to numerous systems and geometric configurations. In the last part of the thesis, experiments on laser dressing processes in attosecond transient absorption spectroscopy are compared to numerical simulations using the DM analysis beyond the RWA.
The research in this thesis opens a pathway to numerous studies using the DM formalism for applications in diverse fields of femtochemistry, attophysics, high precision spectroscopy and quantum information processing.El control quàntic coherent és important per transferir coneixement científic teòric a la tecnologia, per a aplicacions en nombrosos camps. Per aquest motiu, l'estudi del control coherent és significatiu a totes les escales de temps, per comprendre de manera completa els processos dinàmics que es produeixen en els nivells electrònics, atòmics i moleculars. Com a resultat, s'han proposat nombrosos esquemes per dur a terme un control quàntic eficient de diversos sistemes i estudiar la dinàmica d'aquests sistemes basant-se en les seves escales de temps naturals, des dels picosegons (10-12 s), femtosegons (10-15 s) fins a règims d'attosegons (10-18 s). Els objectius d'aquests estudis depenen de l'aplicació desitjada, per exemple, en fotoquímica, un objectiu buscat extensivament és aconseguir una transferència selectiva de la població des d'un estat inicial fins a un estat final desitjat, amb poca o cap disminució de l'energia transferida. En computació quàntica, un tema central és l'excitació dels estats desocupats de Rydberg, amb nombroses propostes per al seu ús en el disseny i implementació de portes quàntiques robustes i ràpides. A més, des de l'arribada de la generació de polsos XUV d'attosegons, s'han obert camins per aconseguir el control de la dinàmica electrònica a escala atòmica i observar-la en temps real. Aquesta tesi explora la modelització de processos dinàmics d'interacció llum-matèria, com ara la inversió efectiva de població i la generació de coherències vibracionals en àtoms i molècules, en les seves escales de temps fonamentals, utilitzant la teoria de la matriu densitat (MD), en l'aproximació d'ona rotant (RWA) i més enllà. La tesi comença introduint el concepte de control coherent de sistemes quàntics simples basats en el formalisme de MD i amplia l'aplicació a un sistema més complexes, com ara oxazines. Es demostra l'esquema multifotó amb polsos p per al control de la transferència de població en sistemes multinivell, per exemple, amb un pols p-tricromàtic que té un conjunt d'àrees v3 p, 2p i v3 p, amb el qual la transferència completa de població en un sistema de quatre nivells pot ser aconseguit. L'esquema esmentat s'utilitza per aconseguir un control eficient d'estats de Rydberg en àtoms de rubidi, i es mostra com aquest control pot ser afectat crucialment per nombrosos processos físics. Un avantatge principal de l'estudi de la matriu densitat comparat amb altres enfocaments teòrics és que permet la possibilitat de computar fàcilment els termes de relaxació i altres paràmetres físics crítics per a un control coherent efectiu. Es demostra que el formalisme de la MD és exitós per descriure correctament l'amplificació d'efectes tant en àtoms com en sistemes moleculars més complexos. El formalisme de la MD és robust en esquemes de control coherent i d'espectroscòpia quàntica i és extensible a nombrosos sistemes i configuracions. En la darrera part de la tesi, es comparen experiments realitzats sobre processos de "vestiment" amb làsers intensos en espectroscòpia d'absorció transitòria d'attosegon amb simulacions numèriques utilitzant l'anàlisi de MD més enllà de la RWA. La recerca en aquesta tesi obre un camí a nombrosos estudis utilitzant el formalisme de MD per a aplicacions en diversos camps de femtoquímica, attofísica, espectroscòpia d'alta precisió i processament d'informació quàntica.
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Kuehner, Joel. "Implementation of an influence matrix approach to failure detection and isolation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0020/MQ54631.pdf.
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Miotti, Bettanini Alvise. "Welding of high performance metal matrix composite materials: the ICME approach." Thesis, KTH, Metallografi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-154021.
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The material development cycle is becoming too slow if compared with other technologies sectors like IT and electronics. The materials scientists’ community needs to bring materials science back to the core of human development. ICME (Integrated Computational Materials Engineer) is a new discipline that uses advanced computational tools to simulate material microstructures, processes and their links with the final properties. There is the need for a new way to design tailor-made materials with a faster and cheaper development cycle while creating products that meet “real-world” functionalities rather than vague set of specifications. Using the ICME approach, cutting edge computational thermodynamics models were employed in order to assist the microstructure characterization and refinement during the TIG welding of a functionally graded composite material with outstanding wear and corrosion resistance. The DICTRA diffusion model accurately predicted the carbon diffusion during sintering, Thermo-Calc and TC-PRISMA models described the thermodynamic and kinetics of harmful carbide precipitation, while COMSOL Multhiphysic furnished the temperature distribution profile at every timestep during TIG welding of the material. Bainite transformation and the influence of chromium and molybdenum was studied and modelled with MAP_STEEL software. The simulations were then compared with experimental observations and a very good agreement between computational works and experiments was found for both thermodynamic and kinetics predictions. The use of this new system proved to be a robust assistance to the classic development method and the material microstructures and processes were carefully adjusted in order to increase corrosion resistance and weldability. This new approach to material development can radically change the way we think and we make materials. The results suggest that the use of computational tools is a reality that can dramatically increase the efficiency of the material development.
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Ballance, Connor Peter. "An r-matrix approach to the continuum processes of diatomic ions." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287326.
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Matte, Marília Luiza. "Matrix representations for integer partitions : some consequences and a new approach." Universidade Federal do Rio Grande do Sul, 2018. http://hdl.handle.net/10183/178603.
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O presente trabalho dedica-se ao estudo de algumas consequências da representação matricial para conjuntos de partições de inteiros e funções mock theta. Na primeira parte do texto, classificamos as partições geradas por seis diferentes funções mock theta, de acordo com a soma das entradas da segunda linha das matrizes associadas, e apresentamos algumas fórmulas fechadas e identidades para essas partições. De nimos também a família ffm (q)gm 1 de funções mock theta, inspiradas pelo que chamamos de versão sem sinal da função f1(q). Fornecemos uma representação matricial análoga para as funções fm (q), o que leva a resultados interessantes a respeito das partições geradas por elas. A parte II do texto trata de uma nova abordagem que gera um conjunto diferente de partições de inteiros. A definição desse conjunto baseia-se na construção de um caminho sobre o reticulado Z2, determinado pela representao matricial para diferentes conjuntos de partições de n, e que liga a reta x + y = n a origem. As novas partições possuem apenas partes mpares distintas, com algumas restições particulares. Esse processo de construção de novas partições, chamado de Path Procedure, e aplicado a partições irrestritas, bem como para partições contadas pelas 1a e 2a Identidades de Rogers-Ramanujan e funções mock theta f5 (q) e T1(q).
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Lekutai, Gaviphat. "Kalman filtering in noisy nonlinear systems using a jump matrix approach." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06112009-063610/.
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Rosengren, Hellman Jonas. "Modular Battery Base Unit : A Method-Based Design Approach." Thesis, KTH, Maskinkonstruktion (Inst.), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-183421.
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This thesis covers a product development process carried out in collaboration with Ericsson –Enclosure & Power and their development of Radio Base Stations (RBS). As Ericsson expands into new markets, the different customer demands on their support systems increases in number and variation. In order to improve their business structure and still provide a wide array of product solutions, they are currently developing a new modular product family. Today numerous methods for product modularization exist, but there is a lack of experience of using such methods at Ericsson – Enclosure & Power. This thesis is an exploration of what methods could be suitable to use in this context, and how to implement them in a beneficial way. The object of study is the Battery Base Unit (BBU), a mounting base for RBS cabinets that contains a compartment for backup batteries. A methodology is suggested for developing this product in a way that secures a proper modular structure. Part of the methodology consists of standard product development methods such as Quality Function Deployment (QFD), concept selection and prototyping. The other part consist of the modularization methods Function Structure Heuristics and Design Structure Matrix (DSM), that are employed first on functional level before developing concepts and secondly on component-based level while detailing the final concept. The thesis describes how these implementations have been made, how the product have been developed from idea to prototype and the resulting product modularity. The final design is evaluated against the product specification and the benefits and drawbacks of using a formalized modularization process for product development at Ericsson – Enclosure & Power are discussed.Detta arbete handlar om den produktutveckling som utförts i samarbete med Ericsson –Enclosure & Power och deras utveckling av kabinett för radiobasstationer (RBS). Ericssons expansion på nya marknader ökar mängden krav på deras olika supportsystem. För att kunna vidareutveckla sin verksamhet och samtidigt erbjuda ett stort antal produktlösningar utvecklar de för närvarande en ny modulbaserad produktfamilj. Idag finns ett flertal metoder för produktmodularisering men man saknar erfarenhet av att arbeta med sådana metoder på Ericsson– Enclosure & Power. Detta arbete undersöker vilka metoder som är lämpliga att använda i detta sammanhang, och hur man på bästa sätt ska implementera dem. Objektet för denna studie är Batteribasenheten (BBUn) som är ett fundament för montering av RBS kabinettet med ett utrymme för reservbatterier. Ett övergripande tillvägagångssätt föreslås för att säkerställa att utvecklingen av denna produkt inkluderar en bra modulär uppbyggnad. Delvis består tillvägagångssättet av vanliga produktutvecklingsmetoder såsom Quality Function Deployment (QFD), koncepturval och prototyper. I övrigt består det i modulariseringsmetoderna Function Structure Heuristics och Design Structure Matrix (DSM) som används först på funktionsnivå innan konceptgenereringsfasen och därefter på komponentnivå under detaljutvecklingen av det slutliga konceptet. Detta arbete beskriver hur dessa metoder har implementerats, hur produktenhar utvecklats från idé till prototyp samt den resulterande produktmodulariteten. Den slutliga utformningen utvärderas mot den angivna kravspecificeringen och fördelarna och nackdelarna med att använda en formaliserad metod för produktutveckling på Ericsson – Enclosure & Power diskuteras.
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Ost, Alexander. "Performance of communication systems : a model-based approach with matrix-geometric methods /." New York : Springer, 2001. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=354041438X.
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Svahn, Carl. "Quantified Interactive Morphological Matrix : An automated approach to aircraft fuel system synthesis." Thesis, Linköping University, Department of Mechanical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7715.
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This report is one part of a masters thesis in mechanical engineeing. Is is executed at the Department of Mechanical Engineering at Linköping Insitute of Technology in cooperation with Saab Aerosystems in Linköping.
A tool for concept generation called a quantified interactive morphological matrix has been created. It is based on rules of thumb and approximations concerning aircraft fuel systems.
The tool can be used for discarding bad concepts, with regard to weight, power consumption and MTBF, during the concept phase of a fuel system design process. The tool is ready for calibration towards a future specific area of use. It is open for validation and optimization and is specifically designed to be easily modified for different future products.
Suggestions for future use has been given concerning expansion, implementation, validation and optimization.
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Kirkpatrick, Michael Gorden. "Optical character recognition : an approach using self- adjusting segmentation of a matrix." Virtual Press, 1997. http://liblink.bsu.edu/uhtbin/catkey/1048390.
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The problem of optical pattern recognition is a broad one. It ranges from identifying shapes in aerial photographs to recognizing letters in hand or machine printed words. This thesis examines many of the issues relating to pattern recognition and, specifically, those pertaining to the optical recognition of characters. It discusses several approaches to various parts of the problem as an illustration of the variety of methods of attack. Some of the particular strengths and weaknesses of those approaches are discussed as well. Finally, a new method of approaching OCR is introduced, developed, and studied. At the conclusion, the study is summarized, the results are examined, and suggestions are made for continued research.Department of Computer Science
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Godwin, Alan. "A multilevel approach to define the hierarchical organisation of extracellular matrix microfibrils." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/a-multilevel-approach-to-define-the-hierarchical-organisation-of-extracellular-matrix-microfibrils(4cbd7f04-1783-42ef-8354-d85ae18c25c9).html.
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Extracellular matrix (ECM) microfibrils are critical components of connective tissues with a wide range of mechanical and cellular signalling functions. The focus of this PhD thesis is the study of two microfibrillar assemblies, fibrillin-1 and collagen VI. Fibrillin is a large ECM glycoprotein which facilitates the deposition of elastin in elastic tissues such aorta, skin and lung and sequesters growth factors in the matrix. Collagen VI is a heteromeric network-forming collagen which is expressed in tissues such as skin, lung, blood vessels and articular cartilage where it anchors cells into the ECM allowing for the transduction of biochemical and mechanical signals. The structures of some individual domains and short fragments of both fibrillin and collagen VI have been solved, but it is not fully understood how they are arranged into microfibrils and how these microfibrils are arranged into tissues. Therefore the aim of this project has been to determine the hierarchical organisation of fibrillin and collagen VI across multiple length scales. The nanoscale structure of the fibrillin microfibril was determined using negative stain TEM and single particle reconstruction. Microfibrils had a hollow tube-like structure with well-defined bead, arm, interbead and shoulder regions. To overcome flexibility observed in the microfibril, separate sub-models of the different fibrillin regions were modelled. The bead region had a complex double layered structure with an interwoven core and ring structures. The arm region had four separate densities which are potentially formed from dimers of fibrillin molecules. Serial block face scanning electron microscopy (SBF-SEM) and electron tomography allowed for the in situ 3D imaging of individual fibrillin microfibrils in ciliary zonule tissue. Microfibrils in ciliary zonule fibres were held together by cross bridges between microfibrils. These ciliary zonule fibres were then organised into larger fascicle-like structures which were stabilised by circumferentially arranged ciliary zonule fibres. The frozen hydrated structure of the collagen VI half-bead was reconstructed using cryo-TEM. The half-bead region had a compact hollow head, and flexible tail regions, the tail regions were linked together by the collagenous interbead region. SBF-SEM and electron tomography of the pericellular matrix (PCM) of murine articular cartilage revealed that the PCM had a meshwork-like organisation formed from globular densities ~30 nm in diameter. Together a combinatorial approach to image ECM microfibrils from the sub-molecular level to intact tissue structures spanning nanometre to millimetre length scales is presented. This provides a better understanding of how fibrillin and collagen VI microfibrils are organised in tissues.
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Louw, Andries N. E. "Matrix costing : an integrated approach to cost accounting for the corporate environment." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51826.
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Thesis (MBA)--Stellenbosch University, 2000.ENGLISH ABSTRACT: This study project investigates the existing theoretical foundations of cost accounting, evaluating new cost accounting techniques and exploring the possibility of integrating cost accounting techniques with behavioural science techniques, into a system which will address classic corporate cost accounting dilemmas. Costing can be broken down into two major disciplines: Cost accounting for management and control purposes, and cost accounting for decision making. This study project will focus critically on cost allocation techniques which form the foundation for all cost related performance measurement and cost analyses techniques, which in turn finally form the justification for all decisions made in the company. This study project will attempt to define a new concept called "matrix costing", which entails the integration of various cost allocation techniques into a system, which will be integrated with existing financial accounting systems, while specifically addressing the issue of income allocation for profitability analyses. This will be accomplished by drawing knowledge from the behavioural sciences. This study project is a combination of a literature review and exploratory review of a proposed new concept. It stops short of researching the validity of "matrix costing" as an alternative costing technique. It does, however, lay the theoretical foundations to explore this topic further.
AFRIKAANSE OPSOMMING: Hierdie studieprojek ondersoek die bestaande teoretiese beginsels van kosteberekening, evalueer nuwe kosteberekeningtegnieke en ondersoek die moontlikheid om kosteberekening te integreer met die gedragswetenskappe, met die doel om klassieke korporatiewe kosteberekeningdilemmas op te los. Kosteberekening kan in twee hoofdissiplines verdeel word: Kosteberekening vir bestuur- en beheerdoeleindes, en kosteberekening vir besluitnemingsdoeleindes. Hierdie studieprojek sal krities op die koste-allokasietegnieke fokus, wat die basis vorm vir alle kosteprestasiemeting en koste-analiesetegnieke, wat uiteindelik veronderstel is om alle besluite in die organisasie te regverdig. Hierdie studieprojek sal ook poog om 'n nuwe konsep te definieer, naamlik "matrikskosteberekening". Matriks-kosteberekening behels die integrasie van verskeie koste-allokasietegnieke om 'n nuwe stelsel te vorm, wat met bestaande rekeningkundige stelsels sal integreer, met die doel om die dilemma van inkomste allokasie aan te spreek vir die doeleindes van winsgewendheidsanalise. Dit sal vermag word deur gebruik te maak van kennis verkry uit die gedragswetenskappe. Die studieprojek is 'n kombinasie van 'n literatuuroorsig en 'n verkennende oorsig van die voorgestelde konsep. Die studieprojek sal nie die geldigheid van matrikskosteberekening as 'n alternatief op huidige kosterekeningtegnieke navors nie. Dit sal wel die teoretiese basis daarstel vir die verdere verkenning van die onderwerp.
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NAPOLI, MARIA LIA. "Complex formations with a block-in-matrix fabric." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2858345.
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Welack, Sven. "Reduced Density Matrix Approach to the Laser-Assisted Electron Transport in Molecular Wires." Master's thesis, Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200600571.
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The electron transport through a molecular wire under the influence of an
external laser field is studied using a reduced density matrix formalism.
The full system is partitioned into the relevant part, i.e. the wire, electron
reservoirs and a phonon bath. An earlier second-order perturbation theory approach of Meier and Tannor for
bosonic environments which employs a numerical decomposition of the spectral
density is used to describe the coupling to the phonon bath and is extended
to deal with the electron transfer between the reservoirs and the molecular wire.
Furthermore, from the resulting time-nonlocal (TNL) scheme a time-local (TL)
approach can be determined. Both are employed to propagate the reduced density
operator in time for an arbitrary time-dependent system Hamiltonian which
incorporates the laser field non-perturbatively.
Within the TL formulation, one can extract a current operator for the open quantum system.
This enables a more general formulation of the problem which is necessary to
employ an optimal control algorithm for open quantum systems in order to
compute optimal control fields for time-distributed target states, e.g. current patterns. Thus, we take
a fundamental step towards optimal control in molecular electronics. Numerical examples of the population dynamics, laser controlled current, TNL vs. TL and optimal control fields are presented to demonstrate the diverse applicability of
the derived formalism.
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Hansen, Christoffer Berge. "A random Matrix Approach to collective Trends of falling and rising Stock Markets." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16328.
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An inverse statistics analysis of one minute stock quotes from 492 large Europeancompanies has revealed the existence of a gain-loss asymmetry in thefollowing index. The gain-loss asymmetry differs from that observed for dailyclosure prices of the Dow Jones Industrial Average [38], as the probability ofthe optimal investment horizon for a gain is higher than that of a loss. Forindividual stocks, the gain-loss asymmetry was observed to only appear forsignificantly larger return-levels. To the best of our knowledge, this is thefirst time such an analysis has been performed on high-frequency data.A principal component analysis was done by performing an eigenvalue decompositionof the correlation matrix from a sliding time-window. The firstprincipal component was observed to describe the market excellently. Its correspondingeigenvalue was observed to be significantly larger than theoreticalpredictions from random matrix theory, implying that the eigenvalue carriesinformation common to all stocks. Using this eigenvalue as an index measuringthe collectivity in the market has revealed the existence of collectivetrends that appear to be stronger during falling than rising markets. Thishas been observed for two different datasets, the above described one minutestock quotes and daily closure prices from 29 stocks composing the DJIA lateFebruary 2008. The observation is in accordance with results of Balogh etal. [40], and provides further support to the speculation of Johansen et al.[37] that a difference in collective trends is the reason behind the gain-lossasymmetry observed in indexes and not for individual stocks for the samereturn-level.The key idea behind the fear factor model of Donangelo et al. [42] has beenstrongly supported by the observation that collective trends appear to bestronger during sharp index drops. As the collectivity increment has beenobserved to be dependent on the size of the index drop, it is suggested thatthe model should incorporate also individual fear factors for economic sectors,in addition to the global fear factor governing the market as a whole. Periodsexhibiting a rising index positively correlated to the strength of collectivityhas indicated the presence of an optimism factor that also should be incorporatedin the fear factor model [42], forcing stocks to rise synchronously.
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Garvin, Peter. "Plasma levels of matrix metalloproteinase‐9 in a normal population : a psychoneuroendocrinological approach." Doctoral thesis, Linköpings universitet, Institutionen för medicin och hälsa, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-14929.
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Several large‐scale epidemiological studies have demonstrated the prognostic significance of psychosocial factors and stress for coronary artery disease (CAD). Observations of sudden changes in CAD incidence have led to the proposal of mechanisms regarding atherosclerotic plaque vulnerability. The collagen‐degrading enzyme matrix metalloproteinase-9 (MMP-9) is increased in rupture‐prone plaques with high inflammatory activity, and circulating levels of MMP-9 are raised in patients with acute coronary syndrome. However, the distribution of MMP‐9 levels and its relations to psychosocial factors and the stress hormone cortisol have not been previously explored in a normal population.The aim of this dissertation was to examine in a normal population the association of circulating levels of MMP-9 with traditional cardiovascular risk factors including levels of C-reactive protein (CRP), with psychosocial factors, and with saliva levels of cortisol. In addition, the reliability of a new method of ambulatory saliva sampling for assessment of cortisol levels was evaluated. A sub‐sample of the Life conditions, Stress, and Health (LSH)-study, a population based study exploring psychoneuroendocrinological pathways mediating the differences in CAD incidence over socioeconomic status, was used. Plasma levels of MMP-9 were examined in a sample randomly drawn from the LSH‐study (n=400), aged 45 to 69 years at enrollment.The main findings were: 1) there was a positive association between plasma MMP-9 levels and total risk load of cardiovascular risk factors. The findings were persistent after adjusting for CRP and could not be attributed to a single risk factor. 2) After adjusting for traditional cardiovascular risk factors and CRP, MMP-9 levels were positively associated with psychosocial risk factors and negatively associated with psychosocial resources. 3) Pooling saliva samples prior to laboratory analysis were as reliable as arithmetic means for assessment of diurnal cortisol variation in a field research setting. 4) There was a positive association between circulating levels of MMP‐9 and saliva levels of cortisol, both diurnal peak level and evening level of cortisol. The observed associations between MMP‐9 and traditional cardiovascular risk factors, psychosocial factors, and saliva cortisol levels suggest a psychoneuroendocrinological pathway linking stress to plaque vulnerability and provide increased understanding of the association between psychosocial factors and CAD.
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Wang, Qing. "Model reduction for dynamic systems with time delays a linear matrix inequality approach /." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38645439.
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Yahya, Wadood. "Image reconstruction from a limited number of samples: a matrix-completion-based approach." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107860.
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Matrix completion problem deals with the reconstruction of a data matrix from a small subset of its entries. It has been recently shown that, under certain conditions, the missing entries can be recovered, when the data matrix has a low rank. However, we cannot provide an accurate reconstruction of the unknown entries even for a low rank matrix under, but not limited to, the following two conditions: First, the number of available entries falls below a certain limit; and second, some of the rows and columns of the matrix are unsampled, i.e., completely unknown. In this thesis, we propose two ways to improve the reconstruction performance. Firstly, when the number of known entries is insufficient for an accurate reconstruction, we propose to use extra information in the form of additional convex constraints, such as the sample mean and non-negativity of the unknown entries. Secondly, when there are unsampled rows and columns in the matrix, we propose the method of multi-stage matrix completion, which reconstructs the unknown entries by borrowing information from neighbouring known entries.We demonstrate the application of the proposed methods in the reconstruction of images with missing pixels. Additionally, these methods find their applicability in the simulation/modeling of natural phenomena encountered in the geo-sciences and geo-engineering, such as characteristics of petroleum reservoirs (e.g., porosity, permeability, fluid saturation); attributes of mineral deposits (e.g., metal content, rock properties, deleterious elements); and spatial and spatiotemporal pollutants in the air, water and soil. These phenomena can be modelled as two-dimensional spatial random processes. An important problem is the reconstruction of the process from a set of spatially distributed samples. However, due to the high cost associated with data acquisition, the number of available data samples is very small and is typically insufficient for performing accurate reconstructions. For this reason, reference models are frequently used to improve the quality of the reconstruction. In this thesis, we cast the spatial simulation/reconstruction problem as a matrix completion problem and we show that matrix completion with added constraints can be used to increase the quality of data sets. More specifically, we propose an improved version of the pre-existing High Order Stochastic Simulation (HOSIM) algorithm, termed HOSIM+, that adds a matrix completion-based pre-processing stage to HOSIM. Furthermore, we show that multi-stage matrix completion can effectively build training images (analogues) that can be used as reference models for spatial simulations and, importantly, are consistent with the data and their high-order spatial statistics, unlike the commonly used training images.Le problème de complétion de matrices concerne la reconstruction d'une matrice de données à partir d'un petit sous-ensemble de ses entrées. Il a été montré récemment, que sous certaines conditions, les entrées manquantes peuvent être récupérées lorsque le rang de la matrice de données est petit. Cependant, une reconstruction précise, même pour une matrice dont le rang est petit, est impossible dans certain cas incluant, sans toutefois s'y limiter, les deux cas suivant: Primo, le nombre d'entrées spécifiées est sous une certaine limite; et secundo quelques colonnes et linges de la matrice n'ont pas été échantillonnées, c'est-à-dire, elles demeurent entièrement inconnues. Dans cette thèse, nous proposons deux façons d'améliorer la performance de la reconstruction. Premièrement, si le nombre d'entrées est insuffisant, nous proposons d'incorporer de l'information additionnelle sous forme de contraintes convexes, telles que la moyenne de l'échantillon et la non-négativité des entrées inconnues. Deuxièmement, si quelques colonnes et linges de la matrice n'ont pas été échantillonnées, nous proposons la méthode de completion multi-étapes, qui complète les entrées manquantes en utilisant de l'information provenant des entrées connues avoisinantes. Nous démontrons l'application des méthodes proposées dans le cadre de la reconstitution d'images avec des pixels manquant. De plus, ces méthodes peuvent êtres utilisées dans la simulation/modélisation de phénomènes naturels propres aux géosciences et à la géo-ingénierie, tels que la caractérisation des réservoirs pétroliers (ex. porosité, perméabilité, saturation des fluides); les attributs des depots minéraux (ex. teneur en métaux, propriétés de la pierre, elements délétères); ainsi que les polluants spatiaux et spatiaux-temporels dans l'air, dans l'eau et dans le sol. Ces phénomènes peuvent êtres modélisés par des processus aléatoires spatiaux deux-dimensionnels. Un problème important est celui de la reconstruction d'un processus à partir d'un ensemble d'échantillons distribués spatialement. Or, à cause des coûts élevés liés à l'acquisition de données, le nombre de données demeure très petit et est généralement insuffisant pourobtenir une reconstruction adéquate. Ainsi, des modèles de reference sont fréquemment utilisés afin d'améliorer la qualité de la reconstruction.Dans cette thèse, nous interprétons le problème de la simulation/reconstruction spatiale comme un problème de complétion de matrices. Nous montrons que cette approche, avec l'inclusion de contraintes additionnelles, peut améliorer la qualité de données. Plus précisément, nous proposons une version améliorée de l'algorithme de simulation stochastique d'ordre élevé (HOSIM) que nous appelons HOSIM+, en ajoutant une étape de prétraitement basée sur la completion de matrices. De plus, nous montrons que la méthode de completion multi-étapes peut créer des images d'entrainement pouvant être utilise comme des modèles de référence pour des simulations spatiales et, contrairement aux images d'entrainement communément utilisé, ells sont compatibles avec les données et avec leurs statistiques spatiales d'ordre élevé.
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Wang, Qing, and 王卿. "Model reduction for dynamic systems with time delays: a linear matrix inequality approach." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38645439.
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Phillips, Adam. "GPU Accelerated Approach to Numerical Linear Algebra and Matrix Analysis with CFD Applications." Honors in the Major Thesis, University of Central Florida, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1635.
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A GPU accelerated approach to numerical linear algebra and matrix analysis with CFD applications is presented. The works objectives are to (1) develop stable and efficient algorithms utilizing multiple NVIDIA GPUs with CUDA to accelerate common matrix computations, (2) optimize these algorithms through CPU/GPU memory allocation, GPU kernel development, CPU/GPU communication, data transfer and bandwidth control to (3) develop parallel CFD applications for Navier Stokes and Lattice Boltzmann analysis methods. Special consideration will be given to performing the linear algebra algorithms under certain matrix types (banded, dense, diagonal, sparse, symmetric and triangular). Benchmarks are performed for all analyses with baseline CPU times being determined to find speed-up factors and measure computational capability of the GPU accelerated algorithms. The GPU implemented algorithms used in this work along with the optimization techniques performed are measured against preexisting work and test matrices available in the NIST Matrix Market. CFD analysis looked to strengthen the assessment of this work by providing a direct engineering application to analysis that would benefit from matrix optimization techniques and accelerated algorithms. Overall, this work desired to develop optimization for selected linear algebra and matrix computations performed with modern GPU architectures and CUDA developer which were applied directly to mathematical and engineering applications through CFD analysis.B.S.
Bachelors
Mathematics
Sciences
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Jun, Jonathan Ho. "An abductive approach to Design Structure Matrix (DSM) partitioning using frequency domain scoring." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118547.
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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 65-66).
A key benefit of the DSM representation is that it gives a visual interpretation of relationships between its elements. The array format allows us to sort the elements using clustering algorithms which try to group the relationships into modules which are as independent as possible. There are a number of clustering algorithms available which may each end up sorting the DSMs differently using different objectives, for example, activities in a time-based DSM can be sequenced to reduce iterations or to improve concurrency. However, most of these algorithms take a deductive approach which results in only one 'optimal' output. If an abductive approach is used instead, multiple solutions can be generated for the user to evaluate, some which may provide insight on useful configurations that he or she may have overlooked. In electrical engineering, we often make use of transforms to convert time domain signals into frequency domain signals in order to glean additional information which may not have been initially apparent. In this respect, using a frequency domain transform on a DSM matrix gives us additional insights into the relationships represented. An example of one such insight would be into the sorted-ness of a DSM to which module cuts can be defined. By applying a frequency transform to a pixel representation of the DSM and examining the transform coefficients, we gain an understanding of what image patterns exist in the DSM. Rules pertaining to these coefficients could then be defined which would classify a DSM as well sorted (with the dependencies being grouped up) or being unsorted (with the dependencies being scattered). This thesis demonstrates the above technique to rank each permutation of an 8x8 matrix on their conformance to certain rules or behaviors in order to filter out useful configurations in an abductive approach. When comparing the highest-ranking hypotheses against the optimal result from other clustering and sequencing algorithms, this algorithm performed on par with them to reduce external dependencies and iterations respectively. The frequency based scoring was also shown to be a useful metric when determining the optimal module cut of a system.
by Jonathan Ho Jun.
S.M. in Engineering and Management
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Massaglia, J. F. "Modelling the sound insulation of corrugated roof structures : an extended transfer matrix approach." Thesis, University of Salford, 2017. http://usir.salford.ac.uk/43778/.
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Over the course of this work, the transfer matrix method (TMM) was implemented and studied for its potential in predicting the sound insulation characteristics of corrugated dual leaf roof structures. A model of periodically connected plates, using Fourier expansions, was derived independently and extended in this work to include the stiffness of connectors and orthotropic plates, and intermediate beams in the framework of the structure. The same principles were applied in deriving the transmission loss through periodically stiffened plates, as a proxy for corrugated panels. At the same time, corrugated plates were modelled as equivalent orthotropic panels, a process which is compatible with the TMM without particular modifications. Infill materials were modelled using simple fluid representations and more complex poroelastic behaviour. The point-connected plate models were combined with the TMM to enable multiple layers of infill materials between the two plates, by using an effective fluid approach. The stiffness of typical roof connectors was obtained with numerical simulations, and used in predicting transmission loss. Corrections were introduced to simulate diffuse laboratory conditions and enable meaningful comparisons to available data. The limitations of a simple orthotropic plate model compared to laboratory measurements and the ribbed plate model were identified. A number of measurements of dual leaf partitions and full roof systems were compared to the TMM and point-connected plate models, finding typically good agreement at low to mid-frequency, and a strong dependence of high frequency transmission loss on connector stiffness.
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Häger, Alexander. "Contextualizing music recommendations : A collaborative filtering approach using matrix factorization and implicit ratings." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167068.
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Recommender systems are helpful tools employed abundantly in online applications to help users find what they want. This thesis re-purposes a collaborative filtering recommender built for incorporating social media (hash)tags to be used as a context-aware recommender, using time of day and activity as contextual factors. The recommender uses a matrix factorization approach for implicit feedback, in a music streaming setting. Contextual data is collected from users' mobile phones while they are listening to music. It is shown in an offline test that this approach improves recall when compared to a recommender that does not account for the context the user was in. Future work should explore the qualities of this model further, as well as investigate how this model's recommendations can be surfaced in an application.
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Gintert, Michael Jason. "A NOVEL APPROACH TO OBTAIN HIGH PERFORMANCE LAYERED SILICATE THERMOSET POLYIMIDE MATRIX NANOCOMPOSITES." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1185469995.
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Zhao, Wancheng. "A Structural Damage Identification Method Based on Unified Matrix Polynomial Approach and Subspace Analysis." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1206652627.
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Baby, Arun Paul. "Comparison of Modal Parameter Estimation using State Space Methods (N4SID) and the Unified Matrix Polynomial Approach." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613731964598438.
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