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Dissertations / Theses on the topic 'R-parameter'
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Kandhai, Sulona. "Investigating the parameter space of viable models for f(R) gravity." Doctoral thesis, Faculty of Science, 2019. http://hdl.handle.net/11427/31181.
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The accelerated expansion of spacetime intuitively points to the existence of new, unknown energy fields pervading the universe, but it is has also spurred the growth of the research field of modified gravity theories. Of these, f(R) theories of gravity is the first and simplest modification to General Relativity, and have been studied extensively for their astrophysical and cosmological predictions. Power law f(R) modifications have been shown to exhibit desirable characteristics, producing the late time accelerated expansion as well as satisfying local tests of gravity. However, there is wide degeneracy among models in this class, and they are known to suffer from cosmological instabilities, which could lead to curvature singularities at finite times. This thesis addresses questions directly relating to model degeneracy and sudden singularities. Cosmologies and cosmological perturbations, resulting from a general broken power law modification to GR are generated, studied and evolved. Simulations are performed using 1+3 space time decomposition of the field equations and a dynamical systems approach to f(R) cosmology. The parameter space of this model, which includes the HuSawicki [6], Starobinsky [96] and Miranda [7] f(R) forms as subclasses, is investigated. It is found that there are regions in the parameter space which are completely singular and bound by continuous curves. We also investigate regions of the parameter space in which the attractive nature of gravity is preserved, and find that these regions intersect. The results of a Markov Chain Monte Carlo analysis significantly narrowed the viable region of the exponent parameter space of the general power law f(R) model. Current cosmological distance data; SNIa (Union 2), BAO (6dFGS, BOSS, SDSS, WiggleZ) as well as the LRG power spectrum (SDSS DR9), were used to obtain these constraints. The best fits are compared with the ΛCDM model, and leads to the conclusion that this class is still a candidate for the gravitational interaction.
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Koziolek, Heiko [Verfasser], and R. [Akademischer Betreuer] Reussner. "Parameter dependencies for reusable performance specifications of software components / Heiko Koziolek ; Betreuer: R. Reussner." Karlsruhe : KIT Scientific Publishing, 2008. http://d-nb.info/1185540741/34.
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Berg-Kralj, Mandy [Verfasser], and R. [Akademischer Betreuer] Sudik. "Die medikamentöse Geburtseinleitung - Parameter für ein erfolgreiches Management / Mandy Berg-Kralj. Betreuer: R. Sudik." Marburg : Philipps-Universität Marburg, 2014. http://d-nb.info/105299492X/34.
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Lexen, Ernst R. [Verfasser], and Peter H. [Akademischer Betreuer] Hauschildt. "Parameter sensitivity of synthetic spectra and light curves of Type Ia supernovae / Ernst R. Lexen. Betreuer: Peter H. Hauschildt." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2014. http://d-nb.info/1048626199/34.
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Müller, Carlheinz R. [Verfasser]. "Populationsgenetische Parameter der Gewebemerkmale der deutschen Bevölkerung und ihre Anwendung bei der Suche nach nicht-verwandten Blutstammzellspendern / Carlheinz R. Müller." Ulm : Universität Ulm. Medizinische Fakultät, 2002. http://d-nb.info/1015323669/34.
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Matthes, Birgit [Verfasser], K. [Akademischer Betreuer] Eder, R. [Akademischer Betreuer] Ringseis, and G. [Akademischer Betreuer] Stangl. "Die Wirkung von Hydrolysaten aus Nahrungsproteinen auf funktionelle Parameter von humanen Aortenendothelzellen / Birgit Matthes. Betreuer: K. Eder ; R. Ringseis ; G. Stangl." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2009. http://d-nb.info/1024937798/34.
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Wenzelburger-Sinner, Christina [Verfasser], and R. [Akademischer Betreuer] Huber. "Vergleich von Schlafarchitektur und Parameter der Schlafqualität bei Patienten/innen mit Chronic Fatigue Syndrome und gesunden Kontrollpersonen / Christina Wenzelburger-Sinner. Betreuer: R. Huber." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1063278619/34.
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Peters, Gunnar [Verfasser], H. [Gutachter] Zwipp, J. [Gutachter] Neidel, and R. [Gutachter] Hoffmann. "Korrelation biomechanischer und MR-tomografischer Parameter in der Verlaufsbeobachtung des Transplantatremodelings nach vorderem Kreuzbandersatz / Gunnar Peters ; Gutachter: H. Zwipp, J. Neidel, R. Hoffmann." Berlin : Humboldt-Universität zu Berlin, 2003. http://d-nb.info/1207643033/34.
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Probst, Sebastian [Verfasser]. "The Moran model with recombination and the long-term evolutionary experiment with E. coli by R. E. Lensk. Modelling, parameter estimation, and simulation / Sebastian Probst." Bielefeld : Universitätsbibliothek Bielefeld, 2018. http://d-nb.info/117198779X/34.
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Müssig, Oliver [Verfasser], R. Willi [Akademischer Betreuer] Grunewald, Lutz [Akademischer Betreuer] Walter, and Ralf [Akademischer Betreuer] Dressel. "Bedeutung des löslichen CD14-Rezeptors in Plasma und Urin als immunologischer Parameter nach Nierentransplantation und sein Verhältnis zu den löslichen Rezeptoren IL2R, CD4 und CD8 / Oliver Müssig. Gutachter: R.-Willi Grunewald ; Lutz Walter ; Ralf Dressel. Betreuer: R.-Willi Grunewald." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2011. http://d-nb.info/1044248033/34.
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Parchami, Sara [Verfasser], and R. [Akademischer Betreuer] Stoll. "Der Einfluss verschiedener Parameter auf den klinischen Langzeiterfolg von Wurzelfüllungen am Zentrum für ZMK der Philipps-Universität Marburg als Beitrag zur internen Qualitätssicherung / Sara Parchami. Betreuer: R. Stoll." Marburg : Philipps-Universität Marburg, 2011. http://d-nb.info/1013256026/34.
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Kattenstroth, Jan-Christoph [Verfasser], Hubert R. [Gutachter] Dinse, and Andreas [Gutachter] Faissner. "Interventionsprogramme zur Leistungssteigerung sensomotorischer und kognitiver Parameter bei Menschen hohen Alters sowie bei Menschen mit erworbenem neurologischem Defizit / Jan-Christoph Kattenstroth ; Gutachter: Hubert R. Dinse, Andreas Faissner ; Fakultät für Biologie und Biotechnologie." Bochum : Ruhr-Universität Bochum, 2013. http://d-nb.info/1226426492/34.
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Klunk, Sergej [Verfasser], Michael [Akademischer Betreuer] Bartels, F. W. R. [Gutachter] Vondran, and Achim [Gutachter] Aigner. "Differenzierung der Ätiologie und Morphologie des Hepatozellulären Karzinoms und der Leberzirrhose - Basierend auf mathematisch-statistischen Analysen der mikroRNA-Profile und laborchemisch-klinischer Parameter : Differenzierung der Ätiologie und Morphologie desHepatozellulären Karzinomsund der Leberzirrhose -Basierend auf mathematisch-statistischen Analysender mikroRNA-Profile und laborchemisch-klinischer Parameter / Sergej Klunk ; Gutachter: F. W. R. Vondran, Achim Aigner ; Betreuer: Michael Bartels." Leipzig : Universitätsbibliothek Leipzig, 2016. http://d-nb.info/1240481721/34.
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Smith, Francis Lee. "Pilot-scale Development of Trickle Bed Air Biofiltration Employing Deep Biofilms, for the Purification of Air Polluted with Biodegradable VOCs." University of Cincinnati / OhioLINK, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1034206999.
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Alkhayuon, Hassan Mazin. "Rate-induced transitions for parameter shift systems." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/35071.
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Rate-induced transitions have recently emerged as an identifiable type of instability of attractors in nonautonomous dynamical systems. In most studies so far, these attractors can be associated with equilibria of an autonomous limiting system, but this is not necessarily the case. For a specific class of systems with a parameter shift between two autonomous systems, we consider how the breakdown of the quasistatic approximation for attractors can lead to rate-induced transitions, where nonautonomous instability can be characterised in terms of a critical rate of the parameter shift. We find a number of new phenomena for non-equilibrium attractors: weak tracking where the pullback attractor of the system limits to a proper subset of the attractor of the future limit system, partial tipping where certain phases of the pullback attractor tip and others track the quasistatic attractor, em invisible tipping where the critical rate of partial tipping is isolated and separates two parameter regions where the system exhibits end-point tracking. For a model parameter shift system with periodic attractors, we characterise thresholds of rate-induced tipping to partial and total tipping. We show these thresholds can be found in terms of certain periodic-to-periodic and periodic-to-equilibrium connections that we determine using Lin's method for an augmented system. Considering weak tracking for a nonautonomous Rossler system, we show that there are infinitely many critical rates at which a pullback attracting solution of the system tracks an embedded unstable periodic orbit of the future chaotic attractor.
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Hamilton, Brian. "Non-stationary sinusoidal parameter estimation." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106316.
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Parameter estimation is an essential step in sinusoidal modelling for additive sound synthesis, speech synthesis, and digital audio effects. This thesis investigates parameter estimation for a non-stationary sinusoidal signal model with a polynomial log-amplitude and a polynomial phase up to a given order. Two existing parameter estimation methods are investigated (the Reassignment Method and the Derivative Method) for the non-stationary sinusoidal model up to second-order. These methods are related to time-frequency reassignment for the spectrogram and they are shown to be biased by the effect of second-order log-amplitude and second-order phase modulations on spectrogram reassignment. Three generalized parameter estimations methods (the Distribution Derivative Method, the Generalized Reassignment Method, and the Generalized Derivative Method) that provide unbiased estimators for the non-stationary sinusoidal model up to any order are presented and formulated in a new, unified framework. These generalized methods are also related to spectrogram reassignment and it is shown that they correct the bias present in the second-order methods. Practical comparisons of the generalized methods and the theoretical lower limits of estimator performance, the Cramér-Rao bounds, are carried out in experimental tests with synthetic signals. For the sake of completeness, another state of the art method (the Quadratic Interpolated Fast Fourier Transform method) based the Fourier transform of a Gaussian windowed signal, is extended to second-order log-amplitude modulation and tested along with the generalized methods.L'estimation des paramètres est une étape essentielle de la modélisation sinusoïdale dans des domaines tels que la synthèse sonore additive, la synthèse vocale, et les effets audio numériques. Cette thèse examine ce problème dans le cas d'un modèle de signal sinusoïdal non-stationnaire, dont l'amplitude logarithmique et la phase sont représentées par deux polynômes d'ordre inférieur ou égal à un entier donné. Deux méthodes d'estimation d'un modèle non-stationnaire d'ordre inférieur ou égal à deux (méthode par réallocation et méthode de la dérivée), toutes deux reliées à la réallocation du spectrogramme dans le domaine temps-fréquence, sont étudiées. Nous démontrons la présence d'un biais d'estimation, conséquence des modulations conjointes au second ordre, d'amplitude logarithmique et de phase, du spectrogramme réalloué.Sont ensuite présentées et reformulées dans un formalisme unificateur trois méthodes d'estimation généralisées (la méthode des distributions dérivées, la méthode de réallocation généralisée, et la méthode de la dérivée généralisée). Nous démontrons que ces méthodes, également liées au spectrogramme réalloué, fournissent des estimateurs non-biaisés pour le modèle sinusoïdal non-stationnaire à tous les ordres et corrigent le biais existant dans le cas des méthodes à l'ordre deux. La comparaison pratique de ces méthodes généralisées, ainsi que l'établissement de la limite théorique de leur performance, sous forme de bornes de Cramér-Rao, sont établies lors de tests expérimentaux sur des signaux synthétiques. Par souci d'exhaustivité, une autre méthode d'estimation de paramètres du modèle sinusoïdal complétant l'état de l'art du domaine (la méthode par transformée de Fourier rapide avec interpolation quadratique), fondée sur la transformée de Fourier d'un signal pondéré par une fenêtre Gaussienne, est étudiée. Après avoir étendu sa formulation au modèle d'amplitude logarithmique d'ordre deux nous la testons et la comparons aux méthodes généralisées dans les mêmes conditions que précédemment.
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Armour, Bernard. "Structured covariance autoregressive parameter estimation." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59559.
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In this thesis, the problem of estimating the autoregressive (AR) parameters of a wide sense stationary process is studied for the application of spectrum estimation of short data records. The approach taken is to first estimate a structured covariance matrix satisfying an optimality criterion and then map the estimate into the AR parameter estimates. Most covariance estimators are based on a least squares prediction error criterion. The new approach taken in this thesis is the use of a maximum likelihood (ML) criterion to obtain better covariance estimates. Both approximate and exact ML algorithms are developed based on an iterative Newton-Raphson technique to maximize the loglikelihood functions. Testing reveals the symmetric centro-symmetric structured covariance provides superior estimates in comparison to the Toeplitz structure and that the exact ML AR parameter estimates are among the lowest variance. Full comparison of the ML and popular AR spectrum estimation techniques is included.
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Jefferson, Robert. "Lines on one-parameter calabi-yau hypersurfaces." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119712.
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In this thesis, we investigate the behavior of families of lines on one-parameter projective hypersurfaces via the inhomogeneous Picard-Fuchs equation satisfied by the normal functions of the corresponding algebraic cycles. Since the algebraic cycles are geometric invariants, their monodromies around singular loci in the complex structure moduli space provide information about the physics of the underlying variety, i.e. of Calabi-Yau manifolds. In particular, such cycles contribute to the calculation of the D-brane superpotential, with an associated mirror symmetry interpretation. Relations to number theory also arise, as the critical values of the superpotential are found to belong to field extensions of the rationals. Additionally, the contribution to the superpotential may have relevance for the scalar supergravity potential, and hence for the landscape of flux vacua and string phenomenology, which serves as further physics motivation for our study.Dans cette these, on examine le comportement de familles de droites sur des hypersurfaces projectives a un parametre en passant par l'equation de Picard-Fuchs inhomogene satisfaite par les fonctions normales de cycles algebriques correspondants. Etant donne que les cycles algebriques sont des invariants geometriques, leur monodromie autour des points singuliers dans l'espace des modules de la structure complexe fournit de l'information sur les proprietes physique de la variete sous-jacente, qui est de Calabi-Yau. Notamment, de tels cycles contribuent a l'evaluation du super-potentiel de D-branes, ayant une interpretation en symetrie miroir associee. On trouve egalement des liens avec la theorie des nombres, car les valeurs critiques du superpotentiel se trouvent appartenir a des extensions de corps des nombres rationnels. De plus, la contribution au superpotentiel pourrait s'averer important pour le potentiel scalaire de supergravite, et ainsi pour le paysage des vides de flux et la phenomenologie des cordes, qui est une source de motivation supplementaire pour poursuivre cette etude.
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Nur, Darfiana. "Parameter estimation of smooth threshold autoregressive models." Curtin University of Technology, School of Mathematics and Statistics, 1998. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=10781.
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This thesis is mainly concerned with the estimation of parameters of a first-order Smooth Threshold Autoregressive (STAR) model with delay parameter one. The estimation procedures include classical and Bayesian methods from a parametric and a semiparametric point of view.As the theoretical importance of stationarity is a primary concern in estimation of time series models, we begin the thesis with a thorough investigation of necessary or sufficient conditions for ergodicity of a first-order STAR process followed by the necessary and sufficient conditions for recurrence and classification for null-recurrence and transience.The estimation procedure is started by using Bayesian analysis which derives posterior distributions of parameters with a noninformative prior for the STAR models of order p. The predictive performance of the STAR models using the exact one-step-ahead predictions along with an approximation to multi-step-ahead predictive density are considered. The theoretical results are then illustrated by simulated data sets and the well- known Canadian lynx data set.The parameter estimation obtained by conditional least squares, maximum likelihood, M-estimator and estimating functions are reviewed together with their asymptotic properties and presented under the classical and parametric approaches. These estimators are then used as preliminary estimators for obtaining adaptive estimates in a semiparametric setting. The adaptive estimates for a first-order STAR model with delay parameter one exist only for the class of symmetric error densities. At the end, the numerical results are presented to compare the parametric and semiparametric estimates of this model.
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Song, Xiaohui 1974. "The parameter identification of a novel speed reducer /." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33994.
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Many a mechanical application involves power transmission from a high-speed motor to a low-speed load. However, existing speed-reduction mechanisms are usually a major sink of energy and information in mechanical transmissions. Energy and positioning information are lost through: (a) friction between sliding components; (b) compliance; and (c) backlash. A novel transmission for speed reduction, Speed-o-Cam, is currently under research at McGill University's Centre for Intelligent Machines (CIM). The transmission is based on the layout of pure-rolling indexing cam mechanisms, and hence, eliminates backlash and friction. Besides zero backlash and low friction losses, Speed-o-Cam also offers the possibility of high stiffness, another essential attribute for high-accuracy applications.This thesis focuses on the aspects of both model development and mechanical-parameter identification of a spherical prototype of Speed-o-Cam. Our main interest lies in identifying the mechanism stiffness. In order to conduct experiments on the prototype, a testbed was designed and fabricated. A mathematical model of the testbed is first formulated. Based on this model and the results of experiments, the parameters of the Speed-o-Cam prototype are identified. In the process, the stiffness and damping parameters of the couplings of the testbed are also identified.
Power efficiency is an important indicator of speed reducing mechanisms. For the Speed-o-Cam prototype, this indicator is also estimated experimentally.
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Campbell, Stuart William. "Shielding gas parameter optimisation in arc welding processes." Thesis, University of Strathclyde, 2015. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25988.
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This thesis is focussed on shielding gas optimisation in gas shielded arc welding processes, and has been conducted along two themes; deriving conditions in which the shielding gas flow rate can be safely reduced, and through the highly novel process of alternating shielding gases. The correct shielding gas flow rate is essential for providing adequate protection to the weld metal during the heating, liquid and solidification stages. Hence, there is an optimum shielding gas flow rate, but this is difficult to define and is often decided on the basis of preference or experience. A multi-disciplined, systematic study has been conducted, which has shown that there is considerable scope to reduce the shielding gas flow rate. Experimental trials have shown that the shielding gas flow rate can be reduced, in a draft-free environment, to 6 l/min, with no degradation in weld quality for the worst draft conditions measured in a typical shipyard fabrication hall, at 10 l/min. This study has resulted in shielding gas flow controllers, preset at 12 l/min, being installed in a large shipyard environment, removing the welding operatives ability to increase the shielding gas flow rate. The application of alternating shielding gases offers clear manufacturing cost reduction benefits which arise from measurable increases in productivity, improved distortion control and re-work reduction, and overall improvements to the mechanical properties of the weld. Arc pressure measurements, and the subsequent derivation of forces acting on the liquid weld metal, have indicated that flow vectors for helium are opposite in direction to that produced by argon, creating a dynamic action within the weld pool. Schlieren visualisation has shown that there is a greater degree of helium entrainment in the primary jet due to a constriction of its flow in the secondary jet, influencing the arc's behaviour and inferring more of the associated benefits.
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Atrash, Amin. "A Bayesian Framework for Online Parameter Learning in POMDPs." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104587.
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Decision-making under uncertainty has become critical as autonomous and semi-autonomous agents become more ubiquitious in our society. These agents must deal with uncertainty and ambiguity from the environment and still perform desired tasks robustly. Partially observable Markov decision processes (POMDPs) provide a principled mathematical framework for modelling agents operating in such an environment. These models are able to capture the uncertainty from noisy sensors, inaccurate actuators, and perform decision-making in light of the agent's incomplete knowledge of the world. POMDPs have been applied successfully in domains ranging from robotics to dialogue management to medical systems. Extensive research has been conducted on methods for optimizing policies for POMDPs. However, these methods typically assume a model of the environment is known. This thesis presents a Bayesian reinforcement learning framework for learning POMDP parameters during execution. This framework takes advantage of agents which work alongside an operator who can provide optimal policy information to help direct the learning. By using Bayesian reinforcement learning, the agent can perform learning concurrently with execution, incorporate incoming data immediately, and take advantage of prior knowledge of the world. By using such a framework, an agent is able to adapt its policy to that of the operator. This framework is validated on data collected from the interaction manager of an autonomous wheelchair. The interaction manager acts as an intelligent interface between the user and the robot, allowing the user to issue high-level commands through natural interface such as speech. This interaction manager is controlled using a POMDP and acts as a rich scenario for learning in which the agent must adjust to the needs of the user over time.Comme le nombre d'agents autonomes et semi-autonomes dansnotre société ne cesse de croître, les prises de décisions sous incertitude constituent désormais un problème critique. Malgré l'incertitude et l'ambiguité inhérentes à leurs environnements, ces agents doivent demeurer robustes dans l'exécution de leurs tâches. Les processus de décision markoviens partiellement observables (POMDP) offrent un cadre mathématique permettant la modélisation des agents et de leurs environnements. Ces modèles sont capables de capturer l'incertitude due aux perturbations dans les capteurs ainsi qu'aux actionneurs imprécis. Ils permettent conséquemment une prise de décision tenant compte des connaissances imparfaites des agents. À ce jour, les POMDP ont été utilisés avec succès dans un éventail de domaines, allant de la robotique à la gestion de dialogue, en passant par la médecine. Plusieurs travaux de recherche se sont penchés sur des méthodes visant à optimiser les POMDP. Cependant, ces méthodes requièrent habituellement un modèle environnemental préalablement connu. Dans ce mémoire, une méthode bayésienne d'apprentissage par renforcement est présentée, avec laquelle il est possible d'apprendre les paramètres du modèle POMDP pendant l'éxécution. Cette méthode tire avantage d'une coopération avec un opérateur capable de guider l'apprentissage en divulguant certaines données optimales. Avec l'aide du renforcement bayésien, l'agent peut apprendre pendant l'éxécution, incorporer immédiatement les données nouvelles et profiter des connaissances précédentes, pour finalement pouvoir adapter sa politique de décision à celle de l'opérateur. La méthodologie décrite est validée à l'aide de données produites par le gestionnaire d'interactions d'une chaise roulante autonome. Ce gestionnaire prend la forme d'une interface intelligente entre le robot et l'usager, permettant à celui-ci de stipuler des commandes de haut niveau de façon naturelle, par exemple en parlant à voix haute. Les fonctions du gestionnaire sont accomplies à l'aide d'un POMDP et constituent un scénario d'apprentissage idéal, dans lequel l'agent doit s'ajuster progressivement aux besoins de l'usager.
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Singh, Ishaan Bir. "TIEGeR: An energy-efficient multi-parameter geographic routing algorithm." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107861.
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Geographic routing algorithms conventionally use one-hop greedy forwarding as their primary routing technique, which might lead to routing voids. Secondary routing schemes used to circumnavigate such routing voids are unfortunately not efficient in terms of throughput and energy consumption. Moreover, node residual energy and link quality are not considered during the routing process. This thesis presents a Two-hop Information based Energy-efficient Geographic Routing (TIEGeR) scheme to achieve effective energy balancing throughout the network, while preventing routing voids by proactively avoiding "local maxima" nodes. Distance to reach destination, node connectivity, link quality, and node residual energy are employed to formulate the routing metric for the TIEGeR. Besides, secondary routing scheme dealing with routing voids is supplemented by the reverse progress mode. The proposed TIEGeR algorithm is implemented and evaluated in an IEEE 802.15.4 environment using both simulation based on NS-2 and experimental testbed based on TI CC2530ZDK nodes. Simulations are used to investigate the performance of TIEGeR in large-scale network topologies. By experiment, we further evaluate and demonstrate the real-life operation and performance advantages of the TIEGeR scheme implemented in the network layer of a WSN using IEEE 802.15.4 MAC/PHY layers. Simulation and experimental results verify the advantages of TIEGeR against conventional geographic routing schemes.Les algorithmes de routage géographique utilisent conventionnellement des techniques avides de renvois à un bond comme leur technique primaire de routage mais ces techniques peuvent aboutir à une impasse. Les techniques secondaires de routage utilisées pour contourner les impasses ne sont malheureusement pas efficaces en termes de débits ou de consommation d'énergie. De plus, l'énergie résiduelle des nœuds et la qualité des liens ne sont pas considérés durant le procédé de routage. Ce mémoire présente une technique de routage géographique écoénergétique (TIEGeR) à deux bonds et basée sur de l'information pour obtenir un équilibre d'énergie efficace à travers le réseau tout en évitant les impasses en empêchant de manière proactive les nœuds maximaux relatifs. La distance pour atteindre la destination, la connexité des nœuds, la qualité des liens, et l'énergie résiduelle des nœuds sont utilisés pour formuler la mesure de routage pour TIEGeR. Par ailleurs, les techniques secondaires de routage traitant les impasses sont complémentées par le mode de progrès inverse. L'algorithme TIEGeR proposé est implémenté et évalué dans un environnement IEEE 802.15.4 en utilisant des simulations basées sur le NS-2 and en utilisant un banc d'essai basé sur les nœuds TI CC2530ZDK. Les simulations sont utilisées pour examiner la performance de TIEGeR dans une topologie de réseaux à grande échelle. Avec le banc d'essais, nous examinons et nous démontrons le fonctionnement et la performance réalisable de la technique TIEGeR quand elle est implémentée dans la couche réseau d'un réseau de capteurs sans-fil qui utilise la couche physique et la couche de contrôle d'accès au support (MAC) du IEEE 802.15.4. Les résultats des simulations et du banc d'essai vérifient les avantages du TIEGeR contre les techniques conventionnelles de routage géographique.
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Johnstone, Alexander C. "Placing a bound on the post-Newtonian parameter [alpha]₂." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81345.
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A method for obtaining a smaller bound for the post-Newtonian parameter alpha 2 is outlined. alpha2 is a parameter in the post-Newtonian formalism associated with violation of Lorentz invariance. The current bound found by Nordvedt, alpha2 < 1.2 x 10 -7, was obtained using solar system data. We show that, by analysing millisecond pulsar profiles and limiting the amount of secular evolution, a smaller bound can be obtained.
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Pereira, Wesley. "Modifying LPC parameter dynamics to improve speech coder efficiency." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32970.
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Reducing the transmission bandwidth and achieving higher speech quality are primary concerns in developing new speech coding algorithms. The goal of this thesis is to improve the perceptual speech quality of algorithms that employ linear predictive coding (LPC). Most LPC-based speech coders extract parameters representing an all-pole filter. This LPC analysis is performed on each block or frame of speech. To smooth out the evolution of the LPC tracks, each block is divided into subframes for which the LPC parameters are interpolated. This improves the perceptual quality without additional transmission bit rate. A method of modifying the interpolation endpoints to improve the spectral match over all the subframes is introduced. The spectral distortion and weighted Euclidean LSF (Line Spectral Frequencies) distance are used as objective measures of the performance of this warping method. The algorithm has been integrated in a floating point C-version of the Adaptive Multi Rate (AMR) speech coder and these results are presented.
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Agar, Julie. "Contact parameter estimation using a space manipulator verification facility." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82459.
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Computer simulations play an important role in the design and verification of space robotic operations since on-orbit tests are impossible to conduct before launch. Thus, accurate computer modelling and simulation of space robotic tasks is essential. Of particular difficulty are space manipulator operations, which involve constrained or contact tasks. Here, the contact dynamics capability in the modelling tools becomes critical for high fidelity simulation. This in turn implies a need for accurate determination of contact parameters, which are used as inputs to contact dynamics simulation. In this work, the identification of contact dynamics parameters based on sensor data obtained during robotic contact tasks is considered.The contact parameter estimation problem is addressed for simple and complex contacting geometries using the SPDM Task Verification Facility Manipulator Test-bed (SMT) at the Canadian Space Agency. The SMT is a space-representative robotic simulation facility. Single- and multiple-point contact parameter estimation software toolboxes were developed and used with SMT experiments. Single point SMT contact experiments were performed with six different payloads. The single point toolbox was used as part of the process of identifying payload stiffness from SMT experimental data.
Multiple point contact parameter estimation experiments with the SMT were conducted using a mock-up of an International Space Station Arm Computer Unit (ACU) as payload. The multiple point toolbox was used to generate contact stiffness, damping and friction estimates. An evaluation of the sensitivity of the parameter estimation algorithm to mismatches in ACU physical dimensions and ACU geometry files was conducted.
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Dudley, Jonathan. "Cosmological parameter estimation using SZ-selected galaxy cluster abundances." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116972.
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The observational record of the growth of structure in the universe over cosmic time offers a unique and invaluable cosmological measure. The abundance and evolutionary history of structure in the universe are dependent upon the parameters which define the cosmological framework. In this work, we formulate a method for deriving cosmological constraints from the observed abundance of galaxy clusters. These objects are the most massive gravitationally collapsed structures in the universe and act as tracers of the underlying density field. We develop a technique for comparing theoretical cluster abundances with observed galaxy cluster catalogs. In this process, we explore and constrain the parameter space for departures from the canonical cosmological model. The motivation and framework for this investigation are presented in the opening chapters. An introduction to modern cosmological theory and methods for calculating theoretical galaxy cluster abundances are presented. A description of the physical observables associated with galaxy clusters follows, including a summary of detection methods. A cluster likelihood, defined through comparisons between observed cluster abundances with those predicted from theory, is developed.The focus of this work rests in the analysis of the cluster likelihood. The fiducial LCDM model is explored and parameter constraints are presented. The cluster dataset is shown to provide useful constraints on numerous parameters and the inclusion of supplementary data is investigated. The cluster-scale normalization parameter sigma_8 is well-constrained by this analysis, where we find sigma_8=0.745+-0.082 when considering only the cluster data and sigma_8=0.796+-0.026 for a combination of cluster and complementary datasets. The normalization of the scaling relation between the cluster observable and its mass and redshift is also constrained by this joint analysis such that, when compared with predictions from numerical simulations, we find A_SZ, meas./A_SZ, fid.=0.82+-0.17. Also explored are two extensions to the standard cosmological model, a non-cosmological-constant form of dark energy and non-Gaussian primordial fluctuations. In both cases the cluster likelihood is demonstrated to provide informative constraints, demonstrating consistency with a cosmological constant form of dark energy and Gaussian primordial fluctuations. Through a combination of cluster and complementary datasets we constrain the dark energy equation of state parameter to be w=-1.07+-0.12. The degree of non-Gaussianity inferred from a catalog of massive galaxy clusters is also constrained, finding f_NL=-36 (-491+456) at 68% confidence for a particular non-Gaussian model.Les données observationnelles de la croissance des structures dans l'univers représentent une mesure cosmologique unique et inestimable. La quantité et l'historique d'évolution des structures dans l'univers dépendent des paramètres qui définissent le contexte cosmologique. Dans le présent travail, nous formulons une méthode pour déduire des contraintes cosmologiques à partir d'observations du nombre d'amas de galaxies. Ces objets demeurent les structures les plus massives à être issues de l'effondrement gravitationnel dans l'univers et agissent comme traceurs du champ de densité sous-jacent. Nous développons une technique servant à comparer le nombre d'amas de galaxies théorique aux données des catalogues d'amas de galaxies observés. Ce faisant, nous explorons et contraignions l'espace de paramètres à la recherche de déviations par rapport au modèle cosmologique standard. L'intérêt et le cadre de travail de cette recherche sont détaillés dans les premiers chapitres. Une introduction à la théorie de la cosmologie moderne et aux méthodes de calcul du nombre théorique d'amas de galaxies sera présentée. Ensuite, nous faisons la description des observables physiques associés aux amas de galaxies, incluant un résumé des méthodes de détection. Nous développons par après une fonction de vraisemblance des amas de galaxies définie par une comparaison entre les amas observés et les amas prédits par la théorie. Le fil conducteur de ce travail réside dans l'analyse de la fonction de vraisemblance des amas de galaxies. Le modèle standard de la cosmologie, dit LCDM, est exploré et les contraintes sur ses paramètres sont présentées. L'utilisation d'ensembles de données sur les amas de galaxies permet d'améliorer les contraintes sur plusieurs de ces paramètres. L'impact sur ces contraintes de l'ajout de données supplémentaires est également considéré. Cette analyse permet de contraindre significativement le paramètre de normalisation des fluctuations à l'échelle des amas de galaxies \sigma_8. Nous obtenons sigma_8=0.745+-0.082 en ne considérant que les données d'amas de galaxies et sigma_8=0.796+-0.026 en ajoutant des ensembles de données complémentaires. La normalisation du rapport d'échelle entre l'observable d'un amas de galaxies et sa masse est aussi contrainte par cette analyse conjointe. En comparant les résultats de notre analyse à ceux de simulations numériques, nous trouvons A_SZ, meas./A_SZ, fid.=0.82+-0.17$. Nous explorons de plus deux extensions au modèle cosmologique standard, une forme d'énergie sombre ne correspondant pas à une constante cosmologique ainsi que des fluctuations primordiales non-Gaussiennes. Dans les deux cas, la fonction de vraisemblance des amas de galaxies a permis de produire des contraintes informatives. Nous contraignons le paramètre de l'équation d'état de l'énergie sombre comme étant w=-1.07+-0.12$. En appliquant la fonction de vraisemblance à un catalogue d'amas de galaxies massifs, nous trouvons que le degré de non-Gaussianité correspond à f_NL=-36 (-491+456), à un niveau de confiance de 68%, pour un modèle de non-Gaussianité donné.
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Shang, Fang. "Parameter estimation algorithms for impulse radio UWB localization systems." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121384.
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Ultra Wideband (UWB) Impulse Radio (IR) technology has attracted considerable attention in the past few years due to its many desirable properties, such as the ability to penetrate through walls and ground, low power spectral density level, immunity to multipath fading and high temporal resolution. UWB radio is not restricted to radar and communications applications, but is also extensively used for indoor localization and tracking. Indeed, IR-UWB is especially well-suited for these applications since it offers centimeter accuracy, has low power requirements and allows for low cost hardware implementations.Precise radio localization and tracking require the prior estimation of one or more key physical parameters, including: Angle of Arrival (AOA), Signal Strength (SS), Time Of Arrival (TOA) and Time Difference Of Arrival (TDOA). In this thesis, we study and design new low-complexity, yet accurate algorithms for parameter estimation in IR-UWB localization systems, including TOA and AOA, under single and multiple users scenarios. The original contributions of the thesis are organized along three main axes as follows.The first problem we consider is the estimation of the TOA along with the Average Power Delay Profile (APDP), in a single-antenna single-user system operating at a sub-Nyquist rate. Indeed, while a priori knowledge of the APDP is assumed in many existing TOA estimators, its estimation has been overlooked in the literature. We assume a multi-cluster parametric model for the APDP and estimate its parameters via log-domain Least-Squares (LS) fitting; the estimated APDP is then used in conjunction with a maximum likelihood criterion to obtain the TOA estimate. Secondly, still in the context of single-user systems, we consider the case where an antenna array is employed at the receiver, and we develop a joint estimator of the TOA and AOA. The proposed method consists of two steps: (1) preliminary estimation of the TOA and APDP using energy-based threshold crossing and log-domain LS fitting, respectively; (2) joint TOA refinement and AOA estimation by local search of a Log-Likelihood Function (LLF) which employs the preliminary estimates from the first step. The derivation of the LLF relies on an original formulation in which the superposition of images from secondary paths is modeled as a Gaussian random process, whose second order statistical properties are characterized by a wideband space-time correlation function. In addition to the APDP, this function incorporates a special gating mechanism to represent the onset of the secondary paths, thereby leading to a novel form of the LLF. Our third and final contribution deals with the extension of these newly proposed estimators to the multi-user case. More specifically, we consider the joint estimation of the TOA and AOA in the presence of Multi-User Interference (MUI), which is known to seriously degrade the estimation accuracy of these parameters. To solve this problem, we propose a new low-complexity approach which now includes three steps: (1) time alignment and averaging of the antenna signals using Time-Hopping (TH) codes to mitigate the effects of MUI; (2) preliminary TOA estimation based on energy detection followed by quadratic averaging; (3) joint TOA and AOA estimation using the previously developed LLF, but extended to account for MUI.The performance of all these newly proposed methods and algorithms is thoroughly investigated by means of numerical simulation experiments over realistic UWB radio channels. Comparisons are made with the current state of the art as well as to closed-form expressions for the Cramer-Rao bound, which are also derived in this thesis. In all cases, significant improvements in estimation accuracy are demonstrated, as compared to existing benchmark approaches.Les technologies d'impulsions radio (IR) à ultra large bande (UWB) n'est pas limitée aux applications radar et de communications et s'avère très utile pour la localisation et le suivi des sources à l'intérieur des édifices. En effet, l'IR-UWB est particulièrement bien adaptée à ce genre d'applications puisqu'elle offre une grande précision (de l'ordre du centimètre), demande une faible consommation de puissance et permet une mise en œuvre électronique à faible coût. Dans cette thèse, nous concevons et portons à l'étude de nouveaux algorithmes à complexité réduite, mais toujours très précis pour l'estimation de paramètres physiques tels que le temps d'arrivée (TOA) et l'angle d'arrivée (AOA),, dans les systèmes de localisation IR-UWB à la fois pour les scénarios à usager unique et multi-usagers. Nos contributions originales s'orientent selon trois axes principaux.Le premier problème que nous abordons est celui de l'estimation du TOA conjointement avec le profil de puissance du retard moyenné (APDP), dans un système à usager simple et antenne unique opérant en régime sub-Nyquist. En effet, bien que la connaissance a priori du APDP soit supposée connue dans de nombreux estimateurs du TOA de ce type, son estimation a été quelque peu négligée dans la littérature. Nous considérons un modèle paramétrique à agglomérats multiples pour l'APDP et estimons ses paramètres au moyen d'un ajustement par la méthode des moindres carrés (LS) dans le domaine logarithmique. L'APDP ainsi obtenu est alors utilisé dans un critère de maximum de vraisemblance (ML) afin d'obtenir l'estimé du TOA. Deuxièmement, toujours dans un contexte d'usager unique, nous considérons le cas où un réseau d'antennes est utilisé au récepteur et développons un estimateur conjoint du TOA et de l'AOA. La méthode proposée consiste en deux étapes : (1) estimation préliminaire du TOA et de l'APDP par dépassement de seuil basé sur l'énergie et par ajustement LS dans le domaine logarithmique, respectivement, (2) raffinement du TOA et estimation de l'AOA, conjointement au moyen d'une recherche locale du maximum de la fonction de vraisemblance (LLF), utilisant les estimés préliminaires de l'étape précédente. La détermination de la LLF repose sur une formulation originale du problème dans laquelle la superposition des images provenant de trajets secondaires est modélisée comme un processus aléatoire Gaussien, dont les propriétés statistiques du second ordre sont caractérisées par une fonction de corrélation spatio-temporelle à large bande. En plus de l'APDP, cette fonction incorpore un mécanisme de déclenchement servant à représenter l'arrivée des trajets secondaires, ce qui conduit à une forme nouvelle de la LLF. Notre troisième et dernière contribution porte sur l'extension des nouveaux estimateurs au cas multi-usagers. Plus précisément, nous considérons l'estimation jointe du TOA et de l'AOA en présence d'interférence multi-usagers (MUI), laquelle peut avoir des effets dévastateurs sur la précision de cette estimation si elle n'est pas tenue en compte. En guise de solution à ce problème, nous proposons une nouvelle approche à complexité réduite et reposant maintenant sur trois étapes: (1) alignement temporel des signaux reçus aux antennes au moyen du code de saut temporel (TH) de l'usager désiré, dans le but de réduire les effets de la MUI; (2) estimation préliminaire des TOA basée sur la détection d'énergie suivie d'un moyennage quadratique; (3) estimation jointe du TOA et de l'AOA par maximisation de la LLF développée précédemment, mais étendue afin de tenir compte de la MUI. Des comparaisons sont faites avec d'autres méthodes de pointe dans ce domaine ainsi qu'avec la borne de Cramer-Rao dont les diverses expressions sont développées dans la thèse. Dans tous les cas soumis à l'étude, des améliorations majeures sont démontrées au niveau de la précision des estimés, en comparaison avec les méthodes existantes.
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Ozturk, Hatice. "Multi parameter computational and experimental investigations into the robustness of cementless total hip replacements." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/195585/.
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Traditional computational and experimental assessments of implant performance are determin- istic; each computational (usually finite element (FE) based) simulation or experiment describes a single situation. While useful information can be gained from these analyses, when the number of variables involved increases, experimental simulations becoming increasingly time consuming and complex. In these cases, computational simulations are increasingly relied upon to predict implant performance. However, even when employing computational simulations to look at the effect of a large number of variables via sweep simulations for example, the problem can become computationally expensive and unfeasible in terms of time required. In the present work, stochastic cornpu tational methods are employed to assess the effect of multi- ple variables on the performance of the cernentless hip replacement. To verify the computational simulations, at each stage of the project, selected scenarios were tested experimentally. To assess implant performance, the following metrics were used: (i) implant micromotion and migration: excessive micromotion and migration are believed to be related to the most common cause of implant failure, implant loosening, and (ii) bone strain; excessive bone strain can result in bone fracture. An initial study on a neutrally positioned stem showed good correlation between the experimental results and the computational predictions. Mesh morphing techniques were employed to allow implant position to change throughout the simulations and assess how this altered the output metrics; it was observed that micromotion and strains generated in the cortex were most sensitive to varus/valgus angle. To further reduce computational expense, a surrogate modelling technique was used to assess the effect of both loading and implant positioning, on micromotion. The surrogate model was verified by selected FE models, placing confidence in the model, and again highlighted that in addition to vertical load, the varus/valgus angle affected the micromotion of cementless implant. Experimental investigations were carried out to corroborate the results obtained computation ally. The novelty of the experimental tests was in the use of an optical system, called digital image correlation (DIC), to measure implant motions and bone strains. This technique enabled non- contact three dimensional measurements to be made. While some qualitative relationships were obtained with FE outputs, good quantitative corroboration between the strain gauge and DIC suggests that DIC is a promising technique for the evaluation of implant performance in vitro.
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Hatzinger, Reinhold, and Brian Francis. "Fitting paired comparison models in R." Institut für Statistik und Mathematik, WU Vienna University of Economics and Business, 2004. http://epub.wu.ac.at/740/1/document.pdf.
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Paired comparison models in loglinear form are generalised linear models and can be fitted using the IWLS algorithm. Unfortunately, the design matrices can become very large and thus a method is needed to reduce computational load (relating to both space and time). This paper discusses an algorithm for fitting loglinear paired comparison models in the presence of many nuisance parameters which is based on partition rules for symmetric matrices and takes advantage of the special structure of the design matrix in Poisson loglinear models. The algorithm is implemented as an R function. Some simple examples illustrate its use for fitting both paired comparison models and (multinomial) logit models. (author's abstract)Series: Research Report Series / Department of Statistics and Mathematics
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Yu, Nuo 1983. "Fixed parameter tractable algorithms for optimal covering tours with turns." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111595.
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Many geometry problems can be solved by transformation to graph problems. Often, both the geometry version and graph version of the problem are NP-hard - and therefore not likely to be solved in polynomial time. One approach to solving these hard problems is to use fixed parameter tractable (FPT) algorithms. We present a framework for developing FPT algorithms for graph problems using dynamic programming, monadic second order logic of graphs, tree-width, and bidimensionality. We use this framework to obtain FPT results for covering tour problems on grid-graphs with turn costs. The results for these problems are not practical, but they demonstrate how the basic framework can be used to quickly obtain FPT results. We provide suggestions on further research to improve our FPT results and to apply our framework to obtain new FPT results.
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Trahey, Martha. "Positive evidence, preemption and parameter resetting in second language acquisition." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61070.
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Within the framework of generative grammar, it is assumed that children are endowed with an innate language faculty called Universal Grammar (UG). Children learn their native language on the basis of the interaction of positive evidence in the input with the principles and parameters of UG. In terms of parameter setting, positive evidence consistent with just one value of a parameter causes the preemption of any incorrect settings hypothesized by the child, in accordance with the Uniqueness Principle (Pinker 1984, Wexler and Culicover 1980) which ensures that only one parameter setting can be held at a time in the child's grammar (Berwick 1985).This thesis investigates the operation of preemption in parameter setting in second language (L2) acquisition in cases where the learner initially adopts the L1 value of a parameter. Focussing on a parametric difference between French and English, namely, the verb movement parameter (Pollock 1989) which relates to (among other things) the placement of adverbs, 58 grade 5 francophone students learning English as a second language in intensive programmes in Quebec schools were exposed over a two week period to a flood of positive evidence on adverb placement in English--input which was consistent with only the English value of the parameter. The results indicate that the subjects did not reset the verb movement parameter to the English value, suggesting that preemption does not function in L2 as in L1 acquisition. Possible explanations for these results and their implications for theories of L2 learnability are developed.
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Benoit, Stephen M. "Towards direct motion and shape parameter recovery from image sequences." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19607.
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This thesis introduces a flexible and general representation of image deformations using a correspondence matrix H. It is shown that these image deformations can be performed and detected using the optimal basis operators derived from the Singular Value Decomposition (SVD) of H. Among other uses, the decomposition can convert the description of an image deformation into a matrix multiplication. The correspondence matrix is used to perform a variety of image transforms, including scale change, image plane rotation and translation. The methodology is also used to independently reproduce the steerable basis operators for the rotation of functions. The correspondence matrix framework is extended to recover the parameters of an image deformation model using appearance-based methods, producing a probability density function of model parameters in a local, strictly feed-forward, fashion. This method solves the inverse mapping problem by learning the forward mapping. One of the goals of this thesis is to show how much shape and motion information can be directly extracted from a scene by local inspection, leading directly to confidence bounds for the model parameters. As an example, oriented, 1-D receptive fields are synthesized to detect local surface shape and motion parameters within cross sections. The recovered local shape and motion parameters are sufficient to produce local estimates of time to collision, focus of expansion and optical flow without solving the global optimization problems of traditional methods.
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Kim, Nam Hyung. "On concurrent error detection schemes for a parameter filter IC." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60049.
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Electronic Support Measures (ESM)-Parameter Filter IC was specifically designed to process radar signal data. This is one of the essential ESM functions which must be done in real-time. Considering the complexity of the Filter IC and its crucial service in Electronic Warfare (EW), fault-tolerance should be an important element of the circuit. However, in the initial design, fault-tolerance was not included. Therefore, fault-tolerance schemes especially suitable for ESM Filter IC are presented in this thesis.A concurrent error detection technique is presented. The method utilizes a code, referred to as MATCH code that is inherent in the function of ESM Filter IC. Effectiveness of the approach is measured by its error coverage. In the analysis of the coverage, error detection capability of MATCH code and probability of fault detection are incorporated. The hardware overhead required to implement a lookup-table which stores MATCH code is also given for various CAM (content-addressable memory) cells.
As an alternative approach, recomputation with rotated comparands (RERC) is suggested for detection of all single errors. The possibility of multiple error detection and single error correction by the same method is also discussed.
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Patel, Ketan. "Frequency and time domain contact parameter estimation for space robotic operations." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19579.
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Computer simulations play a significant role in the development and operation of space systems because of the difficulty in performing ground-based hardware testing and onorbit tests are impossible before the launch of these systems. Hence, accurate modeling and simulation of space robotic tasks involving contact is very crucial. This in turn implies that accurate model (contact) parameters, used as inputs to the software to represent the contact operation being simulated, are imperative. In this work, we addressed the contact parameter estimation problem for simple contacting geometries (one-point contact) and complex contacting geometries (multiple-point contact). Several frequency domain identification strategies were applied to one-point contact parameter estimation problem to estimate contact stiffness and damping. The performance of these frequency domain algorithms was evaluated and compared with time domain identification algorithms. The identification algorithm for multiple point contact scenario to estimate contact stiffness, damping and coefficient of friction was also investigated. We determined the cause for poor estimation results obtained with previous implementation of this identification algorithm and were able to improve the performance of the algorithm. Finally, a thorough evaluation of sensitivity of the algorithm to noise in measured data was conducted.
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Özbay, Hitay. "Parameter indentifiability of ARX models via discrete time nonlinear system controllability." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66094.
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Dev, Abha, Deepak Jain, S. Jhingan, S. Nojiri, M. Sami, and I. Thongkool. "Delicate f(R) gravity models with a disappearing cosmological constant and observational constraints on the model parameters." American Physical Society, 2008. http://hdl.handle.net/2237/11278.
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Wells, Daniel Patrick. "Predicting the longevity of DVD-R media by periodic analysis of Parity, jitter, and ECC performance parameters /." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2526.pdf.
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Chen, Xuesheng. "Precision cold forming modelling, interfacial thermal parameter investigation and tool design optimisation." Thesis, University of Strathclyde, 2002. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=23751.
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Precision cold forming process modelling, thermal contact conductance and optimum shrink-fitted die with profiled interference were studied. The aims of this work have been achieved using analytical, numerical and experimental approaches to the relevant subjects. Several features of the work are presented: (i) an application of systematic modelling IDEFO language, (ii) an equivalent asperity of surface that enables FE simulation of surface deformation and (iii) a shrink-fitted die with profiled interference, which enables compensation for component-error and necessary die surface pre-stresses. Cold forming process was modelled systematically by IDEFO language in general. The most often used iterations, including design and error-compensation procedures, were constructed; basic activities, inputs, resources and constraints were defined and decomposed. These provide a general procedure for precision cold forming design and a base for the following research of this work. A thermal contact conductance (h -value) experimental investigation was conducted based on steady-temperature measurements and devices. h -value as a function of surface texture and interfacial pressure was experimentally investigated; typically, the value changes from 10 kWm⁻²K⁻¹ to 150 kWm⁻²K⁻¹ for changes in surface texture from Ra = 0.3 0.5 , um to Ra =3-5, um , depending on interfacial pressure (<180 MPa). Based on surface measurements and mathematical work, an equivalent asperity for isotropic surface was presented to represent surface geometry. Uniqueness of the equivalent asperity enables simulation of surface deformation by FE technology. Surface textures under interfacial pressure up to 300 MPa were successfully predicted by FE simulations, results being in agreement with surface measurements. h -value is defined as a function of either contact area ratio or local interfacial pressure; a FE model and an approach of integration of local h -value were dev eloped; value of h was successfully predicted by the established FE model and integration. A profiled interference for shrink-fitting die was designed for component-errors compensation and die surface pre-stress. This was achieved by considering the relationship between die pre-deflection and the profiled interference by FE simulations and a minimisation procedure. Both, the equation and minimisation procedure to determine the profiled interference were established analytically. Uniform die surface direct compensation is combined with shrink-fitted die. Component-errors can be controlled to within a few microns.
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Tran, The Truyen. "On conditional random fields: applications, feature selection, parameter estimation and hierarchical modelling." Curtin University of Technology, Dept. of Computing, 2008. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18614.
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There has been a growing interest in stochastic modelling and learning with complex data, whose elements are structured and interdependent. One of the most successful methods to model data dependencies is graphical models, which is a combination of graph theory and probability theory. This thesis focuses on a special type of graphical models known as Conditional Random Fields (CRFs) (Lafferty et al., 2001), in which the output state spaces, when conditioned on some observational input data, are represented by undirected graphical models. The contributions of thesis involve both (a) broadening the current applicability of CRFs in the real world and (b) deepening the understanding of theoretical aspects of CRFs. On the application side, we empirically investigate the applications of CRFs in two real world settings. The first application is on a novel domain of Vietnamese accent restoration, in which we need to restore accents of an accent-less Vietnamese sentence. Experiments on half a million sentences of news articles show that the CRF-based approach is highly accurate. In the second application, we develop a new CRF-based movie recommendation system called Preference Network (PN). The PN jointly integrates various sources of domain knowledge into a large and densely connected Markov network. We obtained competitive results against well-established methods in the recommendation field.On the theory side, the thesis addresses three important theoretical issues of CRFs: feature selection, parameter estimation and modelling recursive sequential data. These issues are all addressed under a general setting of partial supervision in that training labels are not fully available. For feature selection, we introduce a novel learning algorithm called AdaBoost.CRF that incrementally selects features out of a large feature pool as learning proceeds. AdaBoost.CRF is an extension of the standard boosting methodology to structured and partially observed data. We demonstrate that the AdaBoost.CRF is able to eliminate irrelevant features and as a result, returns a very compact feature set without significant loss of accuracy. Parameter estimation of CRFs is generally intractable in arbitrary network structures. This thesis contributes to this area by proposing a learning method called AdaBoost.MRF (which stands for AdaBoosted Markov Random Forests). As learning proceeds AdaBoost.MRF incrementally builds a tree ensemble (a forest) that cover the original network by selecting the best spanning tree at a time. As a result, we can approximately learn many rich classes of CRFs in linear time. The third theoretical work is on modelling recursive, sequential data in that each level of resolution is a Markov sequence, where each state in the sequence is also a Markov sequence at the finer grain. One of the key contributions of this thesis is Hierarchical Conditional Random Fields (HCRF), which is an extension to the currently popular sequential CRF and the recent semi-Markov CRF (Sarawagi and Cohen, 2004). Unlike previous CRF work, the HCRF does not assume any fixed graphical structures.
Rather, it treats structure as an uncertain aspect and it can estimate the structure automatically from the data. The HCRF is motivated by Hierarchical Hidden Markov Model (HHMM) (Fine et al., 1998). Importantly, the thesis shows that the HHMM is a special case of HCRF with slight modification, and the semi-Markov CRF is essentially a flat version of the HCRF. Central to our contribution in HCRF is a polynomial-time algorithm based on the Asymmetric Inside Outside (AIO) family developed in (Bui et al., 2004) for learning and inference. Another important contribution is to extend the AIO family to address learning with missing data and inference under partially observed labels. We also derive methods to deal with practical concerns associated with the AIO family, including numerical overflow and cubic-time complexity. Finally, we demonstrate good performance of HCRF against rivals on two applications: indoor video surveillance and noun-phrase chunking.
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Wambach, Tina. "Effects of epistatic interaction on detection and parameter analysis of quantitative trait loci." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33039.
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Recent scientific support for the involvement of genetic locus interaction in quantitative trait variation and the widespread use of quantitative trait locus (QTL) mapping has resulted in the need to examine those aspects concurrently. Computer software was written to simulate interacting quantitative trait loci (QTLs) in plant populations. Using this software, interacting QTLs were simulated to examine effects of epistasis on the detection of QTLs and the quality of QTL parameter estimates. Simulations involved doubled haploid populations exhibiting two non-epistatic traits and seven epistatic traits, each trait at four levels of heritability. Detection efficiency of QTL main and interaction effects decreased with decreasing heritability. At a given level of broad-sense heritability, traits differed with respect to the relative quality of main-effect detection and interaction-effect detection. Main-effect detection was notably poor for one epistatic locus that has a relatively small additive effect. Position estimates were accurate but their precision deteriorated with decreasing heritability. The quality of QTL effect estimates declined consistently with decreasing heritability, and loss in the accuracy was associated with losses in power of detection.
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Al-Roubaie, Zahra. "Human breast images : segmentation, analysis and conversion to electrical parameter profiles for Semcad-X electromagnetic simulator." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116044.
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Electrical parameter profiles of human breast images can be used to simulate and analyze the anticipated effects on tissue from its interaction with electromagnetic fields involved in the cancer treatment exposure. In part, the success of this approach depends on the accuracy and precision in identifying the different tissue types. In this work, we propose two methods of segmenting human breast images with malignant tumors. The first method of algorithmic partitioning of the image involves manual color-edge contouring of the tissues using a cursor and subsequent identification of the tissue types. For the second method, MRI T1 values and thresholds are used to perform segmentation and we investigate the potential of incorporating edge detection. The first method is effective, while the second lacks precision, but eliminates the need of manual contouring. The images are imported as BMP files into SEMCAD, an electromagnetic simulation tool based on finite-difference time-domain method, which recognizes the grouped tissues and creates a model of the image. The model allows the user to easily assign electrical parameter values to the grouped tissues, according to the measured values reported in the literature.
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Žůrek, Dalibor. "Metody pro analýzu vlastností přenosových vedení." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219854.
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This work focuses on a search of available literature on the theory of transmission lines and verify the possibility of simulation processes on these lines using a suitable simulation program. Initially, for the introduction to the parameters and the phenomenon that characterize the line and are important for understanding the issue. These parameters are then measured and compared with traces from the simulation in program PSpice. In another part of the work, the reader is familiar with the basics of reflectometry and fault detection capabilities on transmission lines with the basic reflectometry methods TDR and FDR, as well as with other methods of OTDR, MSR, and PD-FDR. For the TDR, FDR and MSR methods were made experimental measurements with a view to determining the position of the various types of faults on the tested leadership.
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Ruwe, Christopher J. "How to extend estimation of parameters and moments of stochastic processes to the time continuous case with applications in econometrics using R /." Hamburg : [C.J. Ruwe], 2007. http://d-nb.info/991278585/34.
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Kühner, Pascal R. [Verfasser]. "How perceived mood states change during a 60-minute endurance run and how they interrelate with other physiological and biomechanical parameters = Wie sich die wahrgenommene Stimmung während eines 60-minütigen Dauerlaufs verändert und wie diese mit anderen physiologischen und biomechanischen Parametern interagiert / Pascal R. Kühner." Landau : Universitätsbibliothek Landau, 2011. http://d-nb.info/1013331702/34.
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Schulze, Birgit [Verfasser]. "Ex vivo-Veränderungen von Parametern des Stoffwechselprofils im Rinderblut : ein Beitrag zur Entwicklung von Qualitätsstandards für die Blutentnahme beim Rind / Birgit Schulze." Berlin : Freie Universität Berlin, 2009. http://d-nb.info/1023710196/34.
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Bouaziz, Walid. "Évaluation des effets physiologiques d'un nouveau programme de reconditionnement physique en endurance sur ergocycle chez des sujets de plus de 70 ans avec recherche d'une action spécifique sur le vieillissement cardio-vasculaire et cognitif." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ112/document.
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Contexte : Les sujets âgés représentent un groupe d’âge dont la proportion ne cesse d’augmenter. Ainsi, la lutte contre la sédentarité et la pratique d’une activité physique régulière demeure l’une des principales mesures qui devrait être privilégiée chez les seniors. L’objectif principal de ce travail était de déterminer les effets d’un nouveau protocole de réentraînement en endurance sur ergocycle alternatif « le Programme d’Entraînement Personnalisé sur Cycle à charge constante avec Récupération intermittente » (PEP’C-R) sur les paramètres d’endurance et cardio-respiratoires maximaux chez des seniors de plus de 70 ans. Les objectifs secondaires étaient de déterminer les effets du PEP’C-R sur la fonction vasculaire et les performances cognitives. Résultats : le PEP’C-R permet une amélioration significative des paramètres d’endurance et cardio-respiratoires maximaux et permet aussi d’améliorer la fonction vasculaire et les performances cognitives. Conclusion : Les résultats apportés par ce travail permettront de diffuser le PEP’C-R chez les seniors en bonne santé et ceci dans le cadre de la prescription de programmes de réentraînement à l’effortBackground: Older adults constitute one of the most rapidly growing population groups. Consequently, avoiding an inactive lifestyle and encouraging regular physical activity remains one of the main measures that should be promoted for older adults. The main objective of our study was to determine the effects of a new lightweight protocol including recovery bouts called: “The Intermittent Aerobic Training Program with Recovery bouts” (IATP-R - PEP’C-R in French) for seniors over 70 on maximal cardiorespiratory and endurance parameters. The secondary objectives were to determine the effects of IATP-R on vascular function and cognitive performances. Results: Our results showed that this new “IATP-R” training protocol permits to achieve a significant improvement in both endurance parameters and maximal cardio-respiratory parameters. In addition, the IATP-R permits to improve the vascular function and cognitive performances. Conclusion: The results of this study could be useful to implement this new IATP-R protocol for healthy older adults over 70. This would also be within the framework of prescribing training programs
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Peréz, Mañes Jorge [Verfasser], and R. [Akademischer Betreuer] Stieglitz. "Development of CFD Thermal Hydraulics and Neutron Kinetics Coupling Methodologies for the Prediction of Local Safety Parameters for Light Water Reactors / Jorge Peréz Mañes. Betreuer: R. Stieglitz." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1045663654/34.
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Gatica, Tossi Mario [Verfasser], Hubert R. [Gutachter] Dinse, and Martin [Gutachter] Tegenthoff. "The role of stimulus timing parameters in passively induced plasticity of the human somatosensory system / Mario Gatica Tossi ; Gutachter: Hubert R. Dinse, Martin Tegenthoff ; International Graduate School of Neuroscience." Bochum : Ruhr-Universität Bochum, 2012. http://d-nb.info/1211174573/34.
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ROSHAN, MANESH REZA. "Uptake, Toxicity and Translocation of Engineered Nanoparticles in Plants." Doctoral thesis, Università di Siena, 2017. http://hdl.handle.net/11365/1055368.
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Recent developments on environmental fate models indicate that as nano waste, engineered nanomaterials/nanoparticles (ENM/Ps) could reach terrestrial ecosystems thus potentially affecting environmental and human health. Plants can be therefore exposed to ENM/Ps but controversial data in terms of fate and toxicity are currently available. Furthermore, there is a current lack of information on complex interactions/transformations to which ENM/Ps undergo in the natural environment as for instance with existing toxic compounds. The main aim of current study is to evaluate potential toxicological risks due to the exposure of plants to ENM/Ps in their natural environment, and investigating different routes of exposure (i.e. water and soil). The aim of the first study reported in chapter 1 was to asses behavior and biological effects of titanium dioxide nanoparticles (n- TiO2) (Aeroxide P25, Degussa Evonik) and its interaction with cadmium (CdCl2) in plants using radish seeds (Raphanus sativus parvus) as model species. Radish seeds were exposed to different concentrations of n-TiO2 (range 1-1000 mg/L) and CdCl2 ( range 1-250 mg/L) alone and in combination using a seed germination and seedling growth toxicity test OECD 208. Percentages of seed germination, germination index (GI) and root elongation were calculated. Cell morphology and oxidative stress parameters as glutathione-S-transferase (GST) and catalase activities (CAT) were measured in radish seeds after 5 days of exposure. Z-Average, PdI and Z-potential of n-TiO2 in Milli-Q water as exposure medium were also determined. DLS analysis showed small aggregates of n-TiO2, negative Z-potential and stable PdI in seed’s exposure media. Germination percentage, GI and root length resulted affected by n-TiO2 exposure compared to controls. Exposure of CdCl2 significantly abolished germination % and GI compared to control seeds and a concentration dependent decrease on root elongation was observed against controls (p<0.05). As well, significant decrease of germination %, GI and root elongation was observed in seeds co-exposed to n-TiO2 and CdCl2 at the highest concentrations (1000mg/L n-TiO2 and 250 mg/L CdCl2) compared to co-exposed seeds at low concentration (1mg/L n-TiO2 and 1 mg/L CdCl2) and controls (p<0.05). Root elongation significantly increase compared to controls at the lowest co-exposure concentration (p<0.05). Similarly at intermediate concentrations of 10 and 100 mg/L in co-exposure conditions, n-TiO2 did not affect CdCl2 toxicity. Concerning antioxidant enzymes, a significant increase of CAT activity in seeds exposed to single high n-TiO2 concentration (1000 mg/L) was observed while n-TiO2 (1 mg/ L), CdCl2 (1 and 250 mg/L) and co-exposure resulted significantly decreased compared to controls (p<0.05). Regarding GST activity, a slight increase in seeds exposed to 1000 mg/L n-TiO2 but no significantly was observed, however both n-TiO2 and CdCl2 alone (1 and 250 mg/L, respectively) or in combinations caused a significant decrease in GST activity (p<0.05). Therefore, overall data support the hypothesis that the presence of n-TiO2 do not affect the toxicity of CdCl2 at least at the highest concentration (100 and 250 mg/L) in radish seeds. Morphological alterations in nuclei, vacuoles and shape of radish root cells were observed upon single Cd exposure and not abolished in the presence of n-TiO2. Nevertheless, although n-TiO2 seems not to reduce Cd toxicity at high concentration (up to 250 mg/L), interactions cannot be excluded based on obtained results.
The aim of the second study reported in chapter 2 was to assess if the presence of n-TiO2 might affect elutriate toxicity to radish seeds (R. sativus parvus) seeds as a model species. Radish seeds were exposed to 11 soils (elutriates) alone and in combination with 1 mg/L of n-TiO2 collected from an industrial site located in Taranto area (South East of Italy). Exposure of seeds was performed according to OECD (208) guideline. Then, root elongation, percentages of seed germination and germination index% (GI) were analyzed. In addition, levels of several trace elements were also determined in soils in order to assess their level of contamination and effects on root elongation, seed germination and GI% further discussed. Main results revealed that the presence of n-TiO2 seems not affecting root length, GI % and germination% of seeds compared to seeds exposed to elutriates alone with the exception of only 2 sites. Moreover, the absence of any clear relationship between effects of elutriate on radish seed germination and trace elements levels was observed. Only slight but not significant changes based on levels of trace elements present in soil were observed in growth parameters. In particular levels of Co, Ni, Zn, Cu, Ti and Sn seem to affect radish seeds germination more than others. Regarding co-exposed seeds, the presence of n-TiO2 caused 100% of germination of radish seeds. Furthermore, in comparison to exposed seeds to elutriates alone, root length and GI % resulted more stimulated. Only slight effects on GI% and root length were observed which might be linked to interaction of these elements with n-TiO2. Likewise, it seemed that Co, Se, Sb and As in presence of n-TiO2 are responsible for changes on growth parameters. According on the overall results, soil elutriates alone could not be able to show real toxicity of a contaminated soil on seeds germination and future study should be performed in order to assess their suitability in real exposure scenarios. Therefore, based on observed data further investigations are required in order to assess real environmental scenarios where such particles could be present in soils together with existing contaminants such trace elements.
The purpose of third study reported in chapter 3 chapter was to assess the impact of n-TiO2 alone and in combination with CdCl2 on germination and growth of radish seeds (R. sativus) exposed in vitro (experiment 1) and in vivo (directly into soils) (experiment 2). In experiment 1(in vitro) radish seeds were exposed to n-TiO2 (1 and 1000 mg/L and CdCl2) and CdCl2 (1 and 250 mg/L) alone and in combination (n-TiO2 1, 10, 100, 1000 mg/L and CdCl2 1, 10, 100, 250 mg/L) using a seed germination and seedling growth toxicity test OECD 208.
In experiment 2 (in vivo), radish exposed only to water and then seedling transferred to soils contaminated with n-TiO2 (1 and 1000 mg/L and CdCl2) and CdCl2 (1 and 250 mg/L) alone and in combination (n-TiO2 1, 10, 100, 1000 mg/L and CdCl2 1, 10, 100, 250 mg/L), still following OECD 208 test conditions.
Root length, shoot length and numbers of secondary leaves of all plants from the two experiments (1 and 2) were recorded at day 10 and day 21. Growth parameters of radish at both day 10 and day 21 showed that plants from seeds exposed during germination (experiment 1) resulted more affected by single and co-exposure to n-TiO2 and CdCl2 than those exposed directly in soil (experiment 2). Furthermore, presence of CdCl2 at 250 mg/L alone and in combination with 1000 mg/L of n-TiO2 seemed affect the root and shoot length in both experiments 1and 2 at day 10 and day 21.
Growth parameter analysis of single and co-exposed groups in experiment 1 at day 10, showed a decrease in root length in all tested plants with exception of those exposed to n-TiO2 (1mg/L), co-exposed to n-TiO2 and CdCl2 (1mg/L and 1mg/L), (10 mg/L and 10 mg/L) and (100 mg/L and 10 mg/L) which showed slight increase compared to control. In experiment 2 at day10 only exposed plants to 1000 mg/kg of n-TiO2 revealed significant increase of root length while other all single and co-exposure groups showed a decrease of root length respect to control. Shoot length in exposed plants to all single and co-exposure groups in both experiments 1 and 2 at day 10 showed a decrease compared to control except plants exposed to n-TiO2 and CdCl2 (100 mg/kg and 10 mg/kg) in experiment 2 which showed an increase.
Obtained results on day 21 showed a decrease of root length respect to control on tested plants to all single and co-exposure groups in both experiments 1 and 2 with exception of exposed radish to 1 mg/L of CdCl2 in experiment 1. Shoot length of all tested single and co-exposure groups in experiments 1 and 2 showed a decrease compared to control except radish exposed to 1000 mg/kg of n-TiO2 which revealed an increase in experiment 2. Regarding secondary leaves, in both experiments 1and 2 at day 10 no leaves were shown. On the opposite, (2 leaves) were present at day 21 in most plants exposed to single and in combination, while those exposed to CdCl2 (250 mg/kg), n-TiO2 and CdCl2 (10 and 100 mg/L) and (1000 mg/kg and 250 mg/kg) in experiment 1 showed no leaves. Likewise, exposure n-TiO2 (1000 mg/kg) and co-exposure of n-TiO2 and CdCl2 (10 mg/kg and 100) showed only one secondary leaf in experiment 2 at day 21.