Dissertations / Theses on the topic 'Critical sequence of points'
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Ke, Jie. "Critical points of reaction mixtures." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252011.
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Misner, Scottie, and Carol Curtis. "HACCP - Hazard Analysis Critical Control Points." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/146434.
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1p.HACCP, pronounced has-up, is a food safety self-inspection system that combines up-to-date technical information with step-by-step procedures to evaluate and monitor the flow of food throughout a food establishment from receiving to service. This publication introduces this system to readers and outlines 6 simple HACCP principles to reduce the occurrence of food-borne illness at home.
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Forkéus, Ted. "Distribution of Critical Points of Polynomials." Thesis, Karlstads universitet, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-82941.
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This thesis studies the relationship between the zeroes of complexpolynomials in one variable and the critical points of those polynomials. Our methods are both analytical and statistical in nature, usingtechniques from both complex analysis and probability theory. Wepresent an alternative proof for the famous Gauss-Lucas theorem aswell as proving that the distribution for the critical points of a randompolynomial with real zeroes will converge in probability to the distribution of the zeroes. A simulation of the case with complex zeroesis also presented, which gives statistical support that this holds forrandom polynomials with complex zeroes as well. Lastly, the previous results are then applied to Sendov’s conjecture where we take aprobabilistic approach to this problem.
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Gipsman, Daria. "Critical points of shading: on intensity maxima." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80275.
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The human visual system possesses a remarkable ability to recognize shading patterns and attribute them to 3D shape. In this thesis statistical differences between shading and non-shading patterns are studied.First, a formal analysis of the regions around shading maxima is presented. Second-order approximations of these regions are derived and compared to the approximations of the corresponding surface regions. The analysis supports the observation that the regions around the shading maxima tend to have elongated intensity structure.
Then, statistical properties of the regions around the maxima are discussed and related to the analytic properties of the shading maxima. The second-order coefficients of the shading images are estimated and their distributions are compared with those of the surfaces and the non-shading images. Distinctive properties of the distributions obtained from the shading images can be captured by their normalized third central moment, or skewness coefficient. It's thus concluded that the latter coefficient provides a cue to shading identification.
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Oag, Robert Martin. "Acoustic detection of liquid-vapour critical points." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275286.
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Rizvi, Syed Azhar Abbas Papas Charles Herach Papas Charles Herach. "The critical points of Poynting vector fields /." Diss., Pasadena, Calif. : California Institute of Technology, 1988. http://resolver.caltech.edu/CaltechETD:etd-11082007-131130.
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Å, imÅ ek Alp. "Analysis of critical points for nonconvex optimization." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32108.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 121-125).
In this thesis, we establish sufficient conditions under which an optimization problem has a unique local optimum. Motivated by the practical need for establishing the uniqueness of the optimum in an optimization problem in fields such as global optimization, equilibrium analysis, and efficient algorithm design, we provide sufficient conditions that are not merely theoretical characterizations of uniqueness, but rather, given an optimization problem, can be checked algebraically. In our analysis we use results from two major mathematical disciplines. Using the mountain pass theory of variational analysis, we are able to establish the uniqueness of the local optimum for problems in which every stationary point of the objective function is a strict local minimum and the function satisfies certain boundary conditions on the constraint region. Using the index theory of differential topology, we are able to establish the uniqueness of the local optimum for problems in which every generalized stationary point (Karush-Kuhn-Tucker point) of the objective function is a strict local minimum and the function satisfies some non-degeneracy assumptions. The uniqueness results we establish using the mountain pass theory and the topological index theory are comparable but not identical.
(cont.) Our results from the mountain pass analysis require the function to satisfy less strict structural assumptions such as weaker differentiability requirements, but more strict boundary conditions. In contrast, our results from the index theory require strong differentiability and non-degeneracy assumptions on the function, but treat the boundary and interior stationary points uniformly to assert the uniqueness of the optimum under weaker boundary conditions.
by Alp Simsek.
M.Eng.
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Pears, J. R. "Degenerate critical points and the Conley index." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/15617.
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The thesis has two main themes: some homological results on the Conley index are put into a more natural homotopical context; and degenerate isolated critical points are studied from the point of view of the Conley index theory. A critical point of a smooth function is a rest point of the induced gradient flow so, if isolated, has a Conley index; this is the k-sphere, Sk, if the point is non-degenerate with Morse index k. The question as to which spaces can occur as the Conley index of a (degenerate) critical point is addressed. It is shown that the Lusternik Schnirelmann category of an invariant set (in general) is at least that of its Conley index less one. Consequently, the Conley index of a critical point can have Lusternik Schnirelmann category at most two. Conversely, the suspension of any finite CW-complex is shown to be the Conley index of a critical point of some function. A degenerate critical point may be broken up into a collection of non-degenerate points by perturbing the function in a neighbourhood of the point. The Conley index of the degenerate point is used to study this collection - homotopy invariants are introduced that give lower bounds on the number of critical values obtained in this manner. Despite its homotopical definition, much of the previous work using methods of algebraic topology with the Conley index concentrates on the homological properties of the index. This thesis, exploiting the definition of the Conley index as the homotopy type of a pointed space, studies the implications a flow on a space has on the homotopy of that space. It is shown that S-duality relates the forward and reverse flow Conley indices, generalising and clarifying a known Poincaré duality theorem on the homology of the indices.
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Ding, Xinli. "Generalized critical points analysis of acetylene vibrational dynamics /." view abstract or download file of text, 2004. http://wwwlib.umi.com/cr/uoregon/fullcit?p3120621.
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Thesis (Ph. D.)--University of Oregon, 2004.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 145-154). Also available for download via the World Wide Web; free to University of Oregon users.
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Curiel, Sosa Jose Luis. "Computational modelling of critical points and structural discontinuities." Thesis, Swansea University, 2006. https://cronfa.swan.ac.uk/Record/cronfa43193.
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Mathew, Bijoy. "Implementing a hazard analysis critical control points plan (HACCP)." Menomonie, WI : University of Wisconsin--Stout, 2007. http://www.uwstout.edu/lib/thesis/2007/2007mathewb.pdf.
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Dobbs, Neil. "Critical points, cusps and induced expansion in dimension one." Paris 11, 2006. http://www.theses.fr/2006PA112322.
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Faber, Tristan Friedrich. "Critical points in two-dimensional stationary homogeneous isotropic turbulence." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5527.
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Basic properties of critical points in two dimensions are reviewed and related to the velocity and acceleration field of two-dimensional turbulence. A direct numerical simulation (DNS) of two-dimensional homogeneous isotropic turbulence with an inverse energy cascade and a k−5/3 power law is used to study critical points of these fields. The velocity stagnation point based pair separation model of Goto and Vassilicos (S Goto and J C Vassilicos, 2004, New J.Phys., 6, p.65) is revisited and placed on a sound mathematical foundation. The DNS is used to study the time-asymmetry observed between forward and backward separation. A new method has been employed to obtain values for the Richardson constants and the ratio of them for the backwards and forwards case, which is gb/gf = (0.92±0.03) and hence, exhibits a qualitatively different behaviour from pair separation in three-dimensional turbulence, where gb > gf (J Berg et al. , 2006, Phys.Rev.E, 74(1), p.016304). An explanation for this behaviour based on the timeasymmetry related to the inverse versus forward energy cascade is suggested. Zero Acceleration Points (ZAPs) and flow structures around them are studied using the same DNS. A well-defined classification of ZAPs in terms of the acceleration gradient tensor’s (∇a) invariants is presented. About half of all ZAPs are Anti-ZAPs (with det[∇a] < 0) and the number of vortical and straining ZAPs (with det[∇a] > 0) is about the same. Vortical and straining ZAPs are swept by the local fluid velocity to a good statistical approximation whereas Anti-ZAPs are not. The average life-time of ZAPs seems to scale with the time-scale of the smallest eddies in the turbulence, though ZAPs (in particular vortical ones) are able to survive up to a few integral time scales. The new ZAP classification can also be applied to extended flow regions and a discussion of the length-scales and sizes characterising these regions and the distances between ZAPs is given.
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Bayle, Corinne. "Mise au point d'une méthode d'éthérification sélective en série osidique : étude par résonance magnétique nucléaire des molécules amphiphiles synthétisées." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10139.
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L'objectif de cette these est la mise au point d'une methode d'etherification en serie osidique et l'etude des proprietes des molecules amphiphiles ainsi synthetisees. La methode d'etherification proposee est une methode indirecte qui se deroule en deux etapes: une iodation selective des positions primaires des derives osidiques est effectuee et les derives iodes obtenus sont alkyles a l'aide d'un hypochlorite d'alkyle. Cette methode nous a permis de synthetiser differents ethers osidiques tels que les methyl 6-o-methyl-, 6-o-ethyl-, 6-o-hexyl-, 6-o-octyl-, 6-o-benzyl-a-d-glucopyranoside. Toutes ces molecules sont obtenues avec de bons rendements (de l'ordre de 75%) et sont caracterisees par resonance magnetique nucleaire du proton et du carbone. Cette methode d'alkylation appliquee aux cyclodextrines a permis de synthetiser les per (6-o-methyl)-a- et -b-cyclodextrines avec de bons rendements (environ 70%). Le mecanisme et les limitations de cette methode sont discutes. Les proprietes des derives obtenus ont ensuite ete etudiees. La concentration micellaire critique du methyl 6-o-octyl-a-d-glucopyranoside a ete mesuree (10 mm). En ce qui concerne les cyclodextrines, les proprietes de complexation de la per (6-o-methyl)-b-cyclodextrine avec deux composes modeles hydrophobes (le paranitrophenol et l'anthraquinone 2-sulfonate de sodium) ont ete etudiees par resonance magnetique nucleaire. Afin de mener a bien ces etudes, la sequence 1d-cosy, technique selective de resonance magnetique nucleaire, a ete mise au point. En particulier, nous avons etudie la determination theorique et experimentale d'un des parametres de cette sequence, le delai d efficace, particulierement important dans les sequences 1d selectives. Ces constantes de complexation sont de 500 m#-#1 a 323 k pour le complexe avec le paranitrophenol et de 2000 m#-#1 pour le complexe avec l'anthraquinone 2-sulfonate de sodium
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Aldous, Anthony P. "Counting zeros and critical points of random curves and surfaces." Thesis, Brunel University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435138.
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Karahasanovic, Una. "Fluctuation-driven phase reconstruction at itinerant ferromagnetic quantum critical points." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3188.
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The formation of new phases close to itinerant electron quantum critical points has been observed experimentally in many compounds. We present a unified analytical model that explains the emergence of new types of phases around itinerant ferromagnetic quantum critical points. The central idea of our analysis is that certain deformations of the Fermi surface enhance the phase-space available for low-energy quantum fluctuations and so self-consistently lower the free energy. Using this quantum order-by-disorder mechanism, we find instabilities towards the formation of a spiral ferromagnet and spin-nematic phase close to an itinerant ferromagnetic quantum critical point. Further, we employ the quantum order-by-disorder mechanism to describe the partially ordered phase of MnSi. Using the simplest model of a Stoner-like helimagnetic transition, we show that quantum fluctuations naturally lead to the formation of an unusual phase near to the putative quantum critical point that shares many of the observed features of the partially ordered phase in MnSi. In particular, we predict an angular dependence of neutron scattering that is in good agreement with neutron-scattering data.
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Manzanares-Papayanopoulos, Emilio. "Bulk and interfacial molecular structure near liquid-liquid critical points." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327623.
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Dokchan, Rakporn. "Numerical integration of differential-algebraic equations with harmless critical points." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2011. http://dx.doi.org/10.18452/16318.
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Algebro-Differentialgleichungen (engl. differential-algebraic equations - DAEs) sind implizite singuläre gewöhnliche Differentialgleichungen, die restringierte dynamische Prozesse beschreiben. Sie unterscheiden sich von expliziten gewöhnlichen Differentialgleichungen dahingehend, dass Anfangswerte nicht beliebig vorgegeben werden können. Weiterhin sind in einer DAE neben Integrations- auch Differentiationsaufgaben involviert. Der Differentiationsindex gibt an, wieviele Differentiationen zur Lösung notwendig sind. Seit den 1980er Jahren wird vorwiegend an der Charakterisierung und Klassifizierung regulärer DAEs und der Konstruktion nebst Fundierung von Integrationsmethoden gearbeitet. I. Higueras, R. März und C. Tischendorf haben gezeigt, dass man lineare DAEs mit properem Hauptterm, A(t)(D(t)x(t))'' + B(t)x(t) = q(t), die regulär mit Traktabilitätsindex 2 sind, zuverlässig numerisch integrieren kann - im Unterschied zu linearen DAEs in Standardform. In Publikationen von R. Riaza und R. März wird die Klassifizierungen kritischer Punkten von linearen DAEs an die Verletzung bestimmter Rangbedingungen von Matrixfunktionen im Rahmen des Traktabilitätsindexes geknüpft. Im wesentlichen heißt ein kritischer Punkt harmlos, wenn der durch die inhärente Differentialgleichung beschriebene Fluß nicht tangiert ist. Gegenstand der vorliegenden Arbeit sind lineare quasi-proper formulierte DAEs. Es werden Index 2 DAEs mit harmlosen kritischen Punkten charakterisiert. Unter Verwendung von quasi-zulässigen Projektorfunktionen können neben DAEs, die fast überall gleiche charakteristische Werte haben, nun erstmalig auch solche mit Indexwechseln behandelt werden. Der Hauptteil der Arbeit besteht im Nachweis von Durchführbarkeit, Konvergenz und nur schwacher Instabilität von numerischen Integrationsmethoden (BDF, IRK(DAE)) für lineare Index 2 DAEs mit harmlosen kritischen Punkten, sowie in der Entwicklung von Fehlerschätzern und Schrittweitensteuerung.Differential-algebraic equations (DAEs) are implicit singular ordinary differential equations, which describe dynamical processes that are restricted by some constraints. In contrast to explicit regular ordinary differential equations, for a DAE not any value can be imposed as an initial condition. Furthermore, DAEs involve not only integration problems but also differentiation problems. The differentiation index of a DAE indicates the number of differentiations required in order to solve a DAE. Since the 1980th, research focuses primarily on the characterization and classification of regular problem classes and the construction and foundation of integration methods for simulation software. I. Higueras, R. Maerz, and C. Tischendorf have shown that one can reliably integrate a general linear DAE with a properly stated leading term, A(t)(D(t)x(t))'' + B(t)x(t) = q(t), which is regular with tractability index 2 - in contrast to linear standard form DAEs. The first classification of critical points of linear DAEs has been published by R. Riaza and R. Maerz. Based on the tractability index, critical points are classified according to failures of certain rank conditions of matrix functions. Essentially, a critical point is said to be harmless, if the flow described by the inherent differential equation is not affected. The subject of this work are quasi-proper linear DAEs. Index-2 DAEs with harmless critical points are characterized. Under the application of quasi-admissible projector functions. Besides DAEs which have almost everywhere the same characteristic values, DAEs with index changes can now be discussed for the first time. The main part of the work is to provide a proof of feasibility, convergence, and only weak instability of numerical integration methods (BDF, IRK (DAE)) for linear index-2 DAEs with harmless critical points, as well as the development and testing of error estimators and stepsize control.
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Wensley, Joanne Ruth. "High pressure studies on magnetic metals near quantum critical points." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609926.
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Mittelberg, Mark T. "A critical analysis of the epistemological starting points in presuppositional apologetics." Theological Research Exchange Network (TREN), 1988. http://www.tren.com.
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Trickey, Robert V. "Critical points of discrete potentials in the plane and in space." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/14362/.
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This thesis looks at various problems relating to the value distribution of certain discrete potentials. Chapter 1 - Background material is introduced, the motivation behind this work is explained, and existing results in the area are presented. Chapter 2 - By using a method based on a result of Cartan, the existence of zeros is shown for potentials in both the complex plane and real space. Chapter 3 - Using an argument of Hayman, we expand on an established result concerning these potentials in the complex plane. We also look at the consequences of a spacing of the poles. Chapter 4 - We extend the potentials in the complex plane to a generalised form, and establish some value distribution results. Chapter 5 - We examine the derivative of the basic potentials, and explore the assumption that it takes the value zero only finitely often. Chapter 6 - We look at a new potential in real space which has advantages over the previously examined ones. These advantages are explained. Appendix - The results of computer simulations relating to these problems are presented here, along with the programs used.
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Crow, Daniel. "Emergent universality and quantum critical points in multi-orbital Anderson models." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/12806.
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We apply a joint Renormalised Perturbation Theory and Numerical Renormalisation Group approach to the study of an n-orbital Anderson Model with a Hund's Rule Coupling. We apply the same methods to the analysis of a two-impurity Anderson model, and find the emergence of a single renormalised energy scale on the approach to two types of quantum critical point, such that it is possible to characterise the low energy physics in terms of this energy scale alone.
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Bennett, Thomas. "Exponential asymptotics for integrals with degenerate and non-isolated critical points." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/377148/.
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In this thesis we consider the exponentially improved asymptotic solutions to unbounded multidimensional steepest descent type integrals in the case where the phase function has sets of non-isolated critical points. These sets are connected components of the critical set of the phase function and we consider the case where these sets have both general order of degeneracy and general dimension. We consider first the case of isolated critical points of general order of degeneracy as a lead-in to the general problem. In the isolated case, we justify the reduction of the study of the asymptotic behaviour of the general integral to the study of the asymptotic contribution to each individual critical point by appealing to the Morse lemma and results from the literature regarding the homology group of allowable integration surfaces. In the non-isolated case no such results exist, but we give a first step by appealing to the Morse-Bott lemma to suitably parameterise the integration surface. The analogous homological result does not yet exist and such a derivation is beyond the scope of this thesis, but we proceed to study individual contributions regardless, inspired by how readily the Morse-Bott lemma affords an analogous parameterisation of the integration surface in the non-isolated case. Once this justification is established we focus on individual critical connected components of the phase function. A full hyperasymptotic expansion representing the repeatedly exponentially improved asymptotic contribution to the integral for critical points of this type is derived for the first time, with examples provided to demonstrate this new theory. The case of a general bounded integration region is briefly considered, but we demonstrate that work still needs to be done to extend the theory to this case.
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Kumar, Ameet. "Critical points in the More Electric Aircraft (MEA) converter-machine chain." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23815/.
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This research aims to analyze the critical points of the inverter-to-machine chain used in the actuation system of MEA. To analyze the critical points, it is necessary to investigate the Partial Discharge Inception Voltage (PDIV) of the printed circuit board (PCB, representative models of the high voltage part terminal part of the inverter) by considering the effects of aerospace conditions like pressure, temperature, and humidity. Also, the endurance tests of twisted pairs (TPs, representative models of the turn/turn insulation) at aerospace conditions is investigated. This is necessary to assess the life of the machine when it is stressed by repetitive square wave/sinusoidal AC voltages. These experiments help to find the proper way to design and qualify MEA actuators.
In this research, the effect of AC voltages, space charges at DC, temperature, pressure, and converter waveforms have been analyzed on different PCB models. Results show that an increased temperature decreases the PDIV and a reduction of PDIV is observed also due to a reduction of pressure. It is also analyzed that space charges play an important role in the measurement of PDIV at DC. Finally, the effect of converter waveforms supplied by SiC is analyzed, where it is observed that there is an 8% increase of PDIV as compared to the PDIV in AC. After these entire tests, it is concluded that the HV terminal part is not critical in the sense of PD occurrence.
After the inverter part, the behavior of turn/turn insulation when it is continuously stressed by repetitive square wave/ AC 50 kHz voltages above PDIV has been analyzed. The results obtained from both the supplies are compared with each other to understand the effect of supply type and frequency on the endurance, finally, the effect of humidity on the endurance of the twisted pairs has been analyzed. It is observed after all these endurance tests that the corona-resistant wire cannot endure PD for a long time in aerospace conditions.
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Thapa, Khagendra. "Detection of critical points : the first step to automatic line generalization /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487329662148295.
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Hüsges, Anna Zita. "Probing magnetic fluctuations close to quantum critical points by neutron scattering." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-204647.
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Second-order phase transitions involve critical fluctuations just below and above the transition temperature. Macroscopically, they manifest in the power-law behaviour of many physical properties such as the susceptibility and the specific heat. The power-laws are predicted to be universal, i.e. the same exponents are expected for a certain class of transitions irrespective of the microscopic details of the system. The underlying commonality of such transitions is the divergence of the correlation length ξ and the correlation time ξ_τ of the critical fluctuations at the transition temperature. Both ξ and ξ_τ can be directly observed by neutron scattering experiments, making them an ideal tool for the study of critical phenomena.
At classical phase transitions, the critical fluctuations will be thermal in nature. However, if a second-order transition occurs at T = 0, thermal fluctuations are frozen, and the transition is driven by quantum fluctuations instead. This is called a quantum critical point. The quantum nature of the fluctuations influences observable properties, also at finite temperatures, and causes unusual behaviour in the vicinity of the quantum critical point or the existence of exotic phases, e.g. unconventional superconductivity. Heavy-fermion compounds are a class of materials that is well suited for the study of quantum criticality. They frequently show second-order transitions into a magnetically ordered state at very low temperatures, which can easily be tuned to T = 0 by the application of pressure, magnetic fields or element substitution.
In this thesis, fluctuations near a quantum critical point are investigated for three heavy-fermion systems. CeCu2Si2 shows unconventional superconductivity close to an antiferromagnetic quantum critical point. Results from single-crystal neutron spectroscopy and thermodynamic measurements are discussed and some details are also given about the synthesis of large single crystals. The focus of the study is the comparison of the inelastic response of magnetic and superconducting samples, which are found to be very similar for ΔE > 0.2 meV.
CePdAl has an antiferromagnetic state with partial magnetic frustration. The ordering temperature can be suppressed by Ni substitution towards a quantum critical point. Single-crystal neutron diffraction experiments of three members of the substitution series were analysed. They revealed several unusual effects of the frustrated state in the pure sample, and show that magnetic order and frustration persist in the substituted samples.
YbNi4P2 is a rare example of a compound with ferromagnetic quantum criticality, which has only been studied in the last few years. The aim of the powder neutron spectroscopy experiments presented here was to obtain an overview of the relevant energy scales, i.e. the crystal electric field, local magnetic fluctuations and ferromagnetic fluctuations. Simulations using the program McPhase were performed for a thorough understanding of the crystal electric field.
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Mejía, Miranda Yuri. "The critical points of lattice trees and lattice animals in high dimensions." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43087.
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We study lattice trees and lattice animals in high dimensions.
Lattice trees and animals are interesting combinatorial objects used to model branched polymers in polymer science. They are also of interest in combinatorics and in the study of critical phenomena in statistical physics.
[Abstract portion beginning here modified and differs from the print copy]. Our study takes place in the nearest-neighbor and spread-out models on the d-dimensional integer lattice. On either graph, a lattice animal is a finite connected subgraph, and a lattice tree is an animal without cycles.
Let t_n and a_n be the number of lattice trees and animals with n bonds that contain the origin, respectively. Standard subadditivity arguments provide the existence of the growth constants τ and α, which are the limit, as the dimension d goes to infinity, of the n-th root of t_n and a_n, respectively.] We are interested in the critical points of these models, which are the reciprocals of the corresponding growth constants.
We rigorously calculate the first three terms of a 1/d-expansion for the critical points of nearest-neighbor lattice trees and animals. The proof follows a recursive argument similar to the one used by Hara and Slade (1995), van der Hofstad and Slade (2006), to obtain analogous results for the critical points of self-avoiding walks and percolation.
To provide the leading terms in the expansions, we use a mean-field model, related to the Galton-Watson branching process with critical Poisson offspring distribution, and results obtained with the lace expansion. The leading terms are also calculated in the spread-out model. Then we develop expansions for the nearest-neighbor generating functions and, together with the lace expansion, obtain the first and second correction terms.
Our result gives a rigorous proof for previous work on the subject [11],[21, 36]. Given the algorithmic nature of the proof, it can be extended, with sufficient labor, to compute higher degree terms. It may provide the starting point for proving the existence of an asymptotic expansion with rational coefficients, for the critical point of nearest-neighbor lattice trees.
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Усенко, А. А. "Порядок впровадження системи hazard analysis and critical control points (HACCP) в Україні." Thesis, Молодіжний науковий юридичний форум: [Матеріали міжн. наук.-практ. конф. До дня науки, м. Киїів, НАУ, 18 травня 2018р.] Том 1.- Тернопіль: Вектор, 2018. С. 149-151, 2018. http://er.nau.edu.ua/handle/NAU/34742.
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Потоцький, Ігор Олексійович. "Методи встановлення інтервалів калібрування еталонів та засобів вимірювальної техніки." Doctoral thesis, Київ, 2020. https://ela.kpi.ua/handle/123456789/32606.
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Робота полягає у розробленні методів визначення інтервалів між калібруваннями (міжкалібрувальних інтервалів) робочих еталонів та засобів вимірювальної техніки, які застосовуються у випробувальних та калібрувальних лабораторіях, спрямована на забезпечення метрологічної простежуваності, точності та достовірності результатів вимірювань. У роботі досліджено можливість контролю відповідності метрологічних характеристик еталонів та засобів вимірювальної техніки встановленим нормам із застосуванням контрольних карт накопичених сум (CUSUM-карт). Проведені дослідження показали, що, незважаючи на здатність CUSUM-карт виявляти навіть незначні зміни метрологічних характеристик засобів вимірювальної техніки, час отримання сигналів може бути досить тривалим. Проаналізувавши затримку сигналів на CUSUM-картах та недоліки, що їх спричинюють, було запропоновано новий метод ковзної регресії на CUSUM-карті. Метод заснований на порівнянні кута нахилу регресійної лінії, проведеної за кількома послідовними точками на карті, з розрахованим гранично допустимим. Показано теоретично та доведено
експериментально, що застосування методу ковзної регресії дозволяє зменшити час затримки сигналу про вихід метрологічних характеристик еталонів чи засобів вимірювальної техніки за встановлені границі. Представлено новий підхід до контролю стану засобів вимірювальної техніки шляхом аналізу СКВ результатів спостережень, що вказує на зменшення їх чутливості. Підхід заснований на ймовірнісному аналізі потрапляння СКВ результатів спостережень в певні діапазони розподілу Пірсона. Введено поняття критичної послідовності точок, виникнення якої вказує на зміну чутливості з часом засобу вимірювальної техніки, та коефіцієнт ефективності, який вказує на доцільність застосування того чи іншого підходу. На основі проведених розрахунків та досліджень запропоновано адаптивний алгоритм виявлення критичної послідовності СКВ-точок, який дозволяє контролювати стан робочих еталонів та засобів вимірювальної техніки, спираючись на отримані СКВ результатів спостережень у контрольних точках. Наведено теоретичне та експериментальне обґрунтування розроблених методів, показано в якому випадку необхідно застосовувати той чи інший метод.
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Andersson, Emma, Anders Peterson, and Krasemann Johanna Törnquist. "Introducing a New Quantitative Measure of Railway Timetable Robustness Based on Critical Points." Linköpings universitet, Kommunikations- och transportsystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-92712.
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The growing demand for railway capacity has led to high capacity consumption at times and a delay-sensitive network with insufficient robustness. The fundamental challenge is therefore to decide how to increase the robustness. To do so there is a need for accurate measures that return whether the timetable is robust or not and indicate where improvements should be made. Previously presented measures are useful when comparing different timetable candidates with respect to robustness, but less useful to decide where and how robustness should be inserted. In this paper, we focus on points where trains enter a line, or where trains are being overtaken, since we have observed that these points are critical for the robustness. The concept of critical points can be used in the practical timetabling process to identify weaknesses in a timetable and to provide suggestions for improvements. In order to quantitatively assess how crucial a critical point may be, we have defined the measure RCP (Robustness in Critical Points). A high RCP value is preferred, and it reflects a situation at which train dispatchers will have higher prospects of handling a conflict effectively. The number of critical points, the location pattern and the RCP values constitute an absolute value for the robustness of a certain train slot, as well as of a complete timetable. The concept of critical points and RCP can be seen as a contribution to the already defined robustness measures which combined can be used as guidelines for timetable constructors.
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Rowley, Jeffrey R. "Flammability Limits, Flash Points, and Their Consanguinity: Critical Analysis, Experimental Exploration, and Prediction." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2233.
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Accurate flash point and flammability limit data are needed to design safe chemical processes. Unfortunately, improper data storage and reporting policies that disregard the temperature dependence of the flammability limit and the fundamental relationship between the flash point and the lower flammability limit have resulted in compilations filled with erroneous values. To establish a database of consistent flammability data, critical analysis of reported data, experimental investigation of the temperature dependence of the lower flammability limit, and theoretical and empirical exploration of the relationship between flash points and temperature limits are undertaken. Lower flammability limit measurements in a 12-L ASHRAE style apparatus were performed at temperatures between 300 K and 500 K. Analysis of these measurements showed that the adiabatic flame temperature at the lower flammability limit is not constant as previously thought, rather decreases with increasing temperature. Consequently the well-known modified Burgess-Wheeler law underestimates the effect of initial temperature on the lower flammability limit. Flash point and lower temperature limit measurements indicate that the flash point is greater than the lower temperature limit, the difference increasing with increasing lower temperature limit. Flash point values determined in a Pensky-Martens apparatus typically exceed values determined using a small-scale apparatus above 350 K. Data stored in the DIPPR® 801 database and more than 3600 points found in the literature were critically reviewed and the most probable value recommended, creating a database of consistent flammability data. This dataset was then used to develop a method of estimating the lower flammability limit, including dependence on initial temperature, and the upper flammability limit. Three methods of estimating the flash point, with one based entirely on structural contributions, were also developed. The proposed lower flammability limit and flash point methods appear to predict close to, if not within, experimental error.
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Усенко, А. А. "ПУБЛІЧНЕ АДМІНІСТРУВАННЯ У СФЕРІ ВПРОВАДЖЕННЯ СИСТЕМИ HAZARD ANALYSIS AND CRITICAL CONTROL POINTS (НАССР)." Thesis, Сучасна університетська правова освіта і наука: Матер. VIIІ Міжн. наук.-практ. конф. (м. Київ, НАУ, 23 лютого 2018 р.). Том 1. Тернопіль: Вектор, 2018. C. 254-256, 2018. http://er.nau.edu.ua/handle/NAU/32743.
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Yao, Xudong. "Minimax methods for finding multiple saddle critical points in Banach spaces and their applications." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/2732.
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This dissertation was to study computational theory and methods for ?nding multiple saddle critical points in Banach spaces. Two local minimax methods were developed for this purpose. One was for unconstrained cases and the other was for constrained cases. First, two local minmax characterization of saddle critical points in Banach spaces were established. Based on these two local minmax characterizations, two local minimax algorithms were designed. Their ?ow charts were presented. Then convergence analysis of the algorithms were carried out. Under certain assumptions, a subsequence convergence and a point-to-set convergence were obtained. Furthermore, a relation between the convergence rates of the functional value sequence and corresponding gradient sequence was derived. Techniques to implement the algorithms were discussed. In numerical experiments, those techniques have been successfully implemented to solve for multiple solutions of several quasilinear elliptic boundary value problems and multiple eigenpairs of the well known nonlinear p-Laplacian operator. Numerical solutions were presented by their pro?les for visualization. Several interesting phenomena of the solutions of quasilinear elliptic boundary value problems and the eigenpairs of the p-Laplacian operator have been observed and are open for further investigation. As a generalization of the above results, nonsmooth critical points were considered for locally Lipschitz continuous functionals. A local minmax characterization of nonsmooth saddle critical points was also established. To establish its version in Banach spaces, a new notion, pseudo-generalized-gradient has to be introduced. Based on the characterization, a local minimax algorithm for ?nding multiple nonsmooth saddle critical points was proposed for further study.
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Abass, Yunusa A. Ayala Luis F. "Determination of cricondentherm, cricondenbar and critical points of natural gases using artificial neural networks." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-3512/index.html.
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Casaday, Brian Patrick. "Numerical Simulation of Atmospheric Internal Waves with Time-Dependent Critical Levels and Turning Points." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2570.
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Just as water surface waves are found everywhere on the ocean's surface, internal waves are ubiquitous throughout the atmosphere. These waves constantly propagate and interact with other flows, but these interactions are difficult to observe due to inadequate current technology. Numerical simulations are often utilized in the study of internal waves. In this work, ray theory is used to numerically simulate the interaction of atmospheric internal waves with time-dependent and time-independent background flows, specifically the interaction of small-scale internal waves and large-scale inertial waves. Parameters such as initial wavenumbers and amplitudes of both small internal waves and inertial waves are determined that will cause the small waves to reach a turning point or critical level, or in the case of time-dependent flows, a wavenumber that reaches a critical value. Other parameters that may cause the waves to become unstable are included in the analysis, such as wave steepness and shear instability. These parameters are combined to determine the spectrum of waves that will experience instability during the interaction. Two principal interactions, small-scale internal waves propagating through an infinite wave train and small-scale internal waves propagating through an inertial wave packet, are simulated and compared. For the first interaction, the total frequency is conserved but is not for the latter. This deviance is measured and results show how it affects the outcome of the interaction. The interaction with an inertial wave packet compared to an inertial wave train results in a higher probability of reaching a Jones' critical level and a reduced probability of reaching a turning point, which is a better approximation of outcomes experienced by expected real atmospheric interactions.
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Megaw, Amanda Margaret. "Detection of critical control points for foodborne pathogens within the poultry production and processing chain." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324855.
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Strickson, Amanda J. "Analysis of expressed sequence tags mapping to the critical region of the 5q syndrome." Thesis, Open University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250497.
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Dahlberg, Robert. "THE PROGRAM PATHING TRUST MODEL FOR CRITICAL SYSTEM PROCESS AUTHORIZATION." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/237.
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Since computers are relied upon to run critical infrastructures – from nuclear power plants to electronic battlefield simulations – the concept of a “trusted” or tamperproof system has become even more important. Some applications have become so critical that it is imperative that they run as intended, without interference. The consequences of these systems not running as intended could be catastrophic. This research offers a solution for a key element for protecting these critical servers – validating process invocation sequences. The purpose of this research is to increase operating system security by detecting, validating, and enforcing process invocation sequences within a critical system. If the processes on a critical system are not those that are intended to run or support the critical system, or if a system is able to run processes in an unauthorized sequence, then the system is compromised and cannot be trusted. This research uses a computational theory approach to create a framework for a solution for the process invocation sequence problem. Using the Program Pathing Trust Model, a solution capable of identifying both valid and invalid process invocation sequences is developed.
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Einenkel, Matthias [Verfasser], Konstantin [Akademischer Betreuer] Efetov, and Ilya [Akademischer Betreuer] Eremin. "Superconductivity and competing orders at magnetic quantum critical points / Matthias Einenkel. Gutachter: Konstantin Efetov ; Ilya Eremin." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1089005857/34.
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Gilsbach, Alexandra Philippa [Verfasser], Heiko von der [Akademischer Betreuer] Mosel, and Pawel [Akademischer Betreuer] Strzelecki. "On symmetric critical points of knot energies / Alexandra Philippa Gilsbach ; Heiko von der Mosel, Pawel Strzelecki." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1171821751/34.
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García, Monera María. "r-critical points and Taylor expansion of the exponential map, for smooth immersions in Rk+n." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/50935.
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[EN] Classically, the study of the contact with hyperplanes and hyperspheres has been realized by using the family of height and distance squared functions. On the first part of the thesis, we analyze the Taylor expansion of the exponential map up to order three of a submanifold $M$
immersed in $\r n.$ Our main goal is to show its usefulness for the description of special contacts of the submanifolds with geometrical models.
As we analyze the contacts of high order, the complexity of the calculations increases. In this work, through the Taylor expansion of the exponential map, we characterize the geometry of order
higher than $3$ in terms of invariants of the immersion, so that the effective computations in specific cases become more affordable. It allows also to get new geometric insights.
On the second part of the thesis, we introduce the concept of critical point of a smooth map between submanifolds. If we consider a differentiable $k$-dimensional manifold $M$
immersed in $\r{k+n},$ we know that its focal set can also be
interpreted as the image of the critical points of the {\it normal
map} $\nu(m,u): NM\to \r{k+n}$ defined by $\nu(m,u)=\pi_N(m,u)+
u,$ for $m\in M$ and $u\in N_mM,$ where $\pi_N:NM\to M$ denotes the normal
bundle.
In the same way, the parabolic set of a differential submanifold is given through the analysis of the singularities of the height functions over the submanifold. If we consider a differentiable
$k$-dimensional manifold $M$ immersed in $\r{k+n},$ we know that its parabolic set can also be interpreted as the image of the critical points of the {\it generalized Gauss map} $\psi(m,u):
NM\to \r{k+n}$ defined by $\psi(m,u)= u,$ for $u\in N_mM.$
Finally, we characterize the asymptotic directions as the tangent set of a $k$-dimensional manifold $M$ immersed in $\r{k+n}$ throughout the study of the singularities of the tangent map $\Omega(m,y): TM\to \r{k+n}$ defined by $\Omega(m,y)=\pi(m,y)+y,$
for $y\in T_mM,$ where $\pi:TM\to M$ denotes the tangent bundle.
We describe first the focal set and its geometrical relation to the Veronese of curvature for
$k$-dimensional immersions in $\r{k+n}.$ Then we define the $r$-critical points of a differential map $f:H \to K$ between two differential manifolds and characterize the $2$ and $3$-critical points of the normal map and generalized Gauss map. The number of these
critical points at $m\in M$ may depend on the degeneration of the curvature ellipse and we calculate those numbers in the particular
case that $M$ is an immersed surface in $\r{4}$ for the normal map and $\r{5}$ for the generalized Gauss map.[ES] En general, el estudio del contacto con hiperplanos e hiperesferas se ha llevado a cabo usando la familia de funciones altura y la función distancia al cuadrado. En la primera parte de la tesis analizamos el desarrollo de Taylor de la aplicación exponencial hasta orden 3 de una subvariedad $M$ inmersa en $\r n.$ Nuestro principal objetivo es mostrar su utilidad en el estudio de contactos especiales de subvariedades con modelos geométricos. A medida que analizamos los contactos de orden mayor, la complejidad de las cuentas aumenta. En este trabajo, a través del desarrollo de Taylor de la aplicación exponencial, caracterizamos la geometría de orden mayor que $3$ en términos de invariantes geométricos de la inmersión, por lo que el trabajo con las cuentas en casos especiales se convierte en más manejable. Esto nos permite también obtener nuevos resultados geométricos. En la segunda parte de la tesis se introduce el concepto de punto crítico de una aplicación regular entre subvariedades. Si consideramos una variedad diferenciable $M$ de dimensión $k$ e inmersa en $\r{k+n},$ sabemos que su conjunto focal puede ser interpretado como la imagen de los puntos críticos de la {\it aplicación normal} $\nu(m,u): NM\to \r{k+n}$ definida por $\nu(m,u)=\pi_N(m,u)+ u,$ para $m\in M$ y $u\in N_mM,$ donde $\pi_N:NM\to M$ denota el fibrado normal. De la misma manera, el conjunto parabólico de una subvariedad diferencial viene dado por el análisis de las singularidades de la función altura sobre la subvariedad. Si consideramos una subvariedad $M$ de dimensión $k$ e inmersa en $\r{k+n},$ sabemos que su conjunto parabólico puede ser interpretado como la imagen de los puntos críticos de la {\it aplicación generalizada de Gauss} $\psi(m,u): NM\to \r{k+n}$ definida por $\psi(m,u)= u,$ donde $u\in N_mM.$ Finalmente, caracterizamos las direcciones asintóticas como el conjunto de direcciones del tangente de una subvariedad $M$ de dimensión $k$ e inmersa en $\r{k+n}$ a través del estudio de las singularidades de la aplicación tangente $\Omega(m,y): TM\to \r{k+n}$ definida por $\Omega(m,y)=\pi(m,y)+y,$ para $y\in T_mM,$ donde $\pi:TM\to M$ denota el fibrado tangente. Describimos primero el conjunto focal y su relación geométrica con la Veronese de curvatura para una variedad $k$ dimensional inmersa en $\r{k+n}.$ Entonces, definimos los puntos $r$-críticos de una aplicación $f:H \to K$ entre dos subvariedades y caracterizamos los puntos $2$ y $3$ críticos de la aplicación normal y la aplicación generalizada de Gauss. El número de estos puntos críticos en $m\in M$ depende de la degeneración de la elipse de curvatura y calculamos ese número en el caso particular de una superficie inmersa en $\r{4}$ para la aplicación normal y $\r{5}$ para la aplicación generalizada de Gauss.
[CAT] En general, l'estudi del contacte amb hiperplans i hiperesferes s'ha dut a terme utilitzant la família de funcions altura i la funció distància al quadrat. A la primera part de la tesi analitzem el desenvolupament de Taylor de l'aplicació exponencial fins a ordre 3 d'una subvarietat $M$ immersa en $\r n.$ El nostre principal objectiu és mostrar la seua utilitat en l'estudi de contactes especials de subvarietats amb models geomètrics. A mesura que analitzem els contactes d'ordre major, la complexitat dels comptes augmenta. En aquest treball, a través del desenvolupament de Taylor de l'aplicació exponencial, caracteritzem la geometria d'ordre major que $ 3 $ en termes d'invariants geomètrics de la immersió, de manera que el treball amb els comptes en casos especials es converteix en més manejable. Això ens permet també obtenir nous resultats geomètrics. A la segona part de la tesi s'introdueix el concepte de punt crític d'una aplicació regular entre subvarietats. Si considerem una varietat diferenciable $ M $ de dimensió $ k $ i immersa en $ \r {k + n}, $ sabem que el seu conjunt focal pot ser interpretat com la imatge dels punts crítics de la {\it aplicació normal} $ \nu (m, u): NM \to \r {k + n} $ definida per $ \nu (m, u) = \pi_N (m, u) + o, $ per $ m \in M $ i $ u \in N_mM, $ on $ \pi_N: NM \to M $ denota el fibrat normal. De la mateixa manera, el conjunt parabòlic d'una subvarietat diferencial ve donat per l'anàlisi de les singularitats de la funció altura sobre la subvarietat. Si considerem una subvarietat $ M $ de dimensió $ k $ i immersa en $ \r {k + n}, $ sabem que el seu conjunt parabòlic pot ser interpretat com la imatge dels punts crítics de la {\it aplicació generalitzada de Gauss} $ \psi (m, u): NM \to \r{k + n} $ definida per $ \psi (m, u) = u, $ on $ u \in N_mM. $ Finalment, caracteritzem les direccions asimptòtiques com el conjunt de direccions del tangent d'una subvarietat $ M $ de dimensió $ k $ i immersa en $ \r{k + n} $ a través de l'estudi de les singularitats de l'aplicació tangent $ \Omega (m, y): TM \to \r {k + n} $ definida per $ \Omega (m, y) = \pi (m, y) + y, $ per $ y \in T_mM, $ on $ \pi: TM \to M $ denota el fibrat tangent. Descrivim primer el conjunt focal i la seva relació geomètrica amb la Veronese de curvatura per a una varietat $ k $ dimensional immersa en $ \r{k + n}. $ Llavors, definim els punts $ r $-crítics d'una aplicació $ f: H \to K $ entre dues subvarietats i caracteritzem els punts $ 2 $ i $ 3 $ crítics de l'aplicació normal i l'aplicació generalitzada de Gauss. El nombre d'aquests punts crítics en $ m \in M $ depèn de la degeneració de l'el·lipse de curvatura i calculem aquest nombre en el cas particular d'una superfície immersa en $ \r{4} $ per a l'aplicació normal i $ \r{5} $ per a l'aplicació generalitzada de Gauss.
García Monera, M. (2015). r-critical points and Taylor expansion of the exponential map, for smooth immersions in Rk+n [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/50935
TESIS
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Kaddoura, Mahmoud. "New graduate nurses' perception of critical thinking development in critical care nursing training programs /." Access online resource, 2009. http://scholar.simmons.edu/bitstream/handle/10090/9655/Mahmoud%20Dissertation%207%20%20JULY.pdf?sequence=1.
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Bell, Cameron Pearce MacDonald. "A critical assessment of ages derived using pre-main-sequence isochrones in colour-magnitude diagrams." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/4017.
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In this thesis a critical assessment of the ages derived using theoretical pre-main-sequence (pre-MS) stellar evolutionary models is presented by comparing the predictions to the low-mass pre-MS population of 14 young star-forming regions (SFRs) in colour-magnitude diagrams (CMDs). Deriving pre-MS ages requires precise distances and estimates of the reddening. Therefore, the main-sequence (MS) members of the SFRs have been used to derive a self-consistent set of statistically robust ages, distances and reddenings with associated uncertainties using a maximum-likelihood fitting statistic and MS evolutionary models. A photometric method (known as the Q-method) for de-reddening individual stars in regions where the extinction is spatially variable has been updated and is presented. The effects of both the model dependency and the SFR composition on these derived parameters are also discussed. The problem of calibrating photometric observations of red pre-MS stars is examined and it is shown that using observations of MS stars to transform the data into a standard photometric system can introduce significant errors in the position of the pre-MS locus in CMD space. Hence, it is crucial that precise photometric studies (especially of pre- MS objects) be carried out in the natural photometric system of the observations. This therefore requires a robust model of the system responses for the instrument used, and thus the calculated responses for the Wide-Field Camera on the Isaac Newton Telescope are presented. These system responses have been tested using standard star observations and have been shown to be a good representation of the photometric system. A benchmark test for the pre-MS evolutionary models is performed by comparing them to a set of well-calibrated CMDs of the Pleiades in the wavelength regime 0.4−2.5 μm. The masses predicted by these models are also tested against dynamical masses using a sample of MS binaries by calculating the system magnitude in a given photometric band- pass. This analysis shows that for Teff ≤ 4000 K the models systematically overestimate the flux by a factor of 2 at 0.5 μm, though this decreases with wavelength, becoming negligible at 2.2 μm. Thus before the pre-MS models are used to derive ages, a recalibration of the models is performed by incorporating an empirical colour-Teff relation and bolometric corrections based on the Ks-band luminosity of Pleiades members, with theoretical corrections for the dependence on the surface gravity (log g). The recalibrated pre-MS model isochrones are used to derive ages from the pre-MS populations of the SFRs. These ages are then compared with the MS derivations, thus providing a powerful diagnostic tool with which to discriminate between the different pre- MS age scales that arise from a much stronger model dependency in the pre-MS regime. The revised ages assigned to each of the 14 SFRs are up to a factor two older than previous derivations, a result with wide-ranging implications, including that circumstellar discs survive longer and that the average Class II lifetime is greater than currently believed.
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Villet, William de Gouret. "A model for the implementation of Hazard Analysis Critical Control Points (HACCP) in the white fish industry." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52087.
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Thesis (MBA)--Stellenbosch University, 2001.ENGLISH ABSTRACT: Fish and shellfish are, with very few exceptions, generally considered safe. Food safety laws in many parts of the world are, however, requiring companies to implement programs such as Hazard Analysis Critical Control Point (HACCP) as a means of assuring food safety from harvest to consumption. In South Africa, fishing companies wishing to export products to countries such as the European Union (EU), the United Sates (US), et cetera have, over the past number of years, been required to implement HACCP. Various issues are, however at stake with regards to the successful implementation of HACCP and thus this study project is primarily focused on the application of the HACCP system to the white fish industry. The method of study involved consultation with various local authorities in order to highlight existing HACCP problems within the South African White Fish Industry. A literature survey was conducted to ascertain the requirements of various countries and international organisations and iii addition to gain an in-depth knowledge as to theworking requirements of HACCP. Prior to setting in place a HACCP system, the model reviews in detail the HACCP manual requirements and prerequisite programs required. The prerequisite programs are not limited to but include good manufacturing practices, operation and sanitation, pest control, traceability and recall procedures, customer complaint procedures, chemical control program and training. Process flow diagrams need to be developed and verified for each process and product. Once completed an analysis of the various biological, chemical and physical hazards that are likely to affect the safety of the product is conducted. The seven principles of HACCP are clarified together with how they may best be implemented and monitored, taking in to consideration the various parameters of each fish processing establishment. A brief introduction about the relationship between the HACCP system, ISO 9000 and total quality management (TOM) and the advantages and disadvantages of each system is included. The study project is completed with recommendations for further study in other food processing industries. Recommendations include, but are not limited to ensuring that current and new legislation be regularly monitored, HACCP models be developed for industries such as the shellfish industry, et cetera and that, where possible, harmonisation of the requirements be internationally agreed upon.
AFRIKAANSE OPSOMMING: Oor die algemeen word vis en skulpvis, met 'n paar uitsonderings, as veilig beskou. Internasionaal word daar deur die voedsel veiligheidswette vereis dat maatskappye aan 'n standaard naamlik HACCP ( Hazard Analysis Critical Control Point) voldoen wat verseker dat die voedsel vanaf sy oorspronklike bron tot en met by die verbruiker veilig is vir gebruik. In Suid Afrika, word oor die laaste aantal jare van alle vismaatskappye wat vis wil uitvoer na Europeuse lande of die Verenigde state, verwag om HACCP te implimenteer. Verskeie kwessies is op die spel met betrekking tot die suksesvolle implimentering van HACCP en daarom word hierdie projek gefokus op die suksesvolle implimenteering van die HACCP beginsel in die witvis bedryf. Vir die studie is plaaslike owerhede genader om vas te stel waar bestaande probleme met betrekking tot die witvis bedryf is. 'n Literatuur studie is uitgevoer om te bepaal wat die behoeftes is van verskillende lande en internationale instansies en ook om 'n indiepte kennis te bekom vir die funksionerings vereistes van HACCP. Die model beskryf volledig wat vereis word om 'n HACCP handleiding saam te stel en die voorvereiste programme wat benodig word alvorens 'n HACCP plan inwerking gestel kan word. Daar is geen beperkings ten opsigte van die voorvereiste programme nie maar dit sluit die volgende in: goeie vervaardigings praktyke, higiëne bestuur, plaagbeheer, identifiseering en produk ontrekking prosedure, verbruikersklagtes, chemikalië beheer en opleiding. Vir elke proses en produk moet daar 'n vloei diagram opgestel word. Daarna moet 'n ontleding gedoen word van alle moontlike biologiese, chemiese en fisiese gevare wat die veiligheid van 'n produk kan benadeel. Verder bespreek die studie die sewe beginsels van HACCP, die implimentering en monitering daarvan met inagneming van die uniekheid van elke prosesaanleg. 'n Kort oorsig oor die verwantskap tussen HACCP, ISO 9000 en "TQM ( Total Quality Management)" met elk se voor en nadele word ook bespreek. Die studie word afgesluit met aanbevellings vir verdere studies in die voedselprosesseringsindustrie, oor die monitering van huidige en toekomstige wetgewing, die ontwikkeling van HACCP modelle en harmonisering van internasionale en plaaslike vereistes soos ooreengekom.
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Pretorius, Luzaan. "A critical analysis of the employees' tax implications of loyalty points awarded to employees in South Africa." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/26507.
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Since the introduction of frequent flyer miles (e.g. Voyager miles) in South Africa, the concept has evolved in a number of ways. Currently, loyalty programmes are widely used in the consumer industry. Despite the fact that these programmes have been in place for several years, the South African Revenue Service (hereafter referred to as SARS) has failed to issue any legislation or guidance with regard to the treatment of these miles from an employees’ tax perspective. The fringe benefit implications of frequent flyer miles have been the topic of research both in South Africa and abroad. However, little research has been identified on the tax implications of loyalty programmes. This study re-examined past studies and literature identified on frequent flyer miles and analysed the impact these have on loyalty points earned on personal and corporate credit cards from an employees’ tax perspective. The study also extended past research and investigated loyalty points awarded to employees as an incentive from an employees’ tax perspective. The study had three specific objectives. The first objective was to analyse past research studies, court cases and other literature in order to establish the theoretical construct of this study. Secondly, it compared the treatment of frequent flyer miles earned by, or awarded to, employees in South Africa to the treatment of these in Australia and Canada. The third objective was to analyse the employees’ tax implications of loyalty points earned by, or awarded to, employees in specific scenarios. These scenarios were limited to loyalty points earned by employers on corporate credit cards and which are awarded to employees for personal use; loyalty points earned on personal credit cards as a result of business expenditure incurred by employees; and loyalty points awarded to an employee, as part of a loyalty programme operated by the employer, as an incentive. The concluding argument of this study was that loyalty points earned on corporate or personal credit cards, which are used for the benefit of employees, may be considered not to be taxable and that consequently, no employees’ tax obligation will arise. However, this argument is plagued by uncertainties and it is questionable as to whether this view will be supported by the South African courts and SARS. In the scenario where loyalty points are awarded as an incentive to employees, it may clearly be argued that these should be taxable with the result that an employees’ tax obligation will arise. However, the nature and value of the benefit, as well as the point at which the tax event occurs, may create inequities and is therefore uncertain. All these uncertainties highlight the need for guidance in this area from SARS. AFRIKAANS : Sedert gereelde vlugmyle (bv. Voyager miles) in Suid-Afrika in plek gestel is, het hierdie konsep in verskeie vorms ontwikkel. Vandag word lojaliteitsprogramme algemeen in die verbruikersbedryf gebruik. Ten spyte van die feit dat hierdie programme vir baie jare reeds in plek is, het die Suid-Afrikaanse Inkomstediens (hierna verwys na as SAID) steeds geen wetgewing of leiding uitgereik oor die hantering van hierdie myle uit ’n werknemersbelastingsoogpunt nie. Alhoewel die byvoordeelimplikasies van gereelde vlugmyle die onderwerp was van navorsing in Suid-Afrika sowel as oorsee is min navorsing geïdentifiseer oor die belastingimplikasies van lojaliteitsprogramme. Hierdie studie heroorweeg bestaande studies en literatuur oor gereelde vlugmyle en analiseer die impak daarvan op lojaliteitspunte verdien op persoonlike en sakekredietkaarte uit ’n werknemersbelastingsoogpunt. Die studie sal ook bestaande navorsing uitbrei deur lojaliteitspunte, wat as ’n aansporing aan werknemers gegee word, uit ’n werknemersbelastingsoogpunt te analiseer. Die studie het drie spesifieke oogmerke. In die eerste plek is dit om bestaande navorsingstudies, hofsake en ander literatuur te analiseer om ’n teoretiese basis te vestig. Tweedens is dit om die belastinghantering van gereelde vlugmyle verdien deur of toegeken aan werknemers in Suid-Afrika te vergelyk met die hantering hiervan in Australië en Kanada. Die derde oogmerk is om die werknemersbelastingimplikasies van lojaliteitspunte toegeken aan of verdien deur werknemers in spesifieke scenario’s krities te analiseer. Hierdie scenario’s is beperk tot lojaliteitspunte verdien deur werkgewers op sakekredietkaarte en toegeken aan werknemers vir persoonlike gebruik; lojaliteitspunte verdien deur werknemers weens sake-uitgawes aangegaan op persoonlike kredietkaarte; en lojaliteitspunte, wat deel vorm van ’n lojaliteitsprogram wat deur die werkgewer bedryf word, gegee aan werknemers as ’n aansporingsbonus. Volgens die studie se bevindinge kan daar aangevoer word dat lojaliteitspunte verdien op sake- en persoonlike kredietkaarte vir werknemers se persoonlike gebruik nie belasbaar is nie en gevolglik geen werknemersbelastingverpligting teweeg bring nie. Nietemin gaan hierdie siening gepaard met baie onsekerhede en word bevraagteken of dit deur die Suid-Afrikaanse howe en SAID ondersteun sal word. In die scenario waar lojaliteitspunte aan werknemers as ’n aansporing gegee word, kan dit duidelik aangevoer word dat hierdie voordeel belasbaar is en dus ’n werknemersbelastingverpligting teweegbring. Daar is egter onsekerheid oor die tydstip waarop die voordeel belas moet word, asook die aard en waarde van die belasbare byvoordeel. Hierdie onsekerhede onderstreep die behoefte aan leiding op hierdie onderwerp vanaf SAID.Dissertation (MCom)--University of Pretoria, 2010.
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Mizdrak, Pedrag. "Novel iterative approach to joint sequence alignment and tree inference under maximum likelihood: A critical assessment." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28253.
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Multiple sequence alignment (MBA) and phylogeny tree reconstruction are two imporant problems in bioinformatics. In some respect, they represent "two sides of the same coin", since solving either of the two problems would be easier if the solution to the other problem was given. However, most of the currently available algorithms present a solution to only one of these two problems, either completely ignoring the other problem or assuming that its solution is known in advance. Attempts have been made to solve these two problems simultaneously, but they are either too computationally intensive or inappropriate to analyze divergent sequences. Here we derive a new method that addresses these shortcomings by iteratively improving the starting alignment and its corresponding evolutionary tree based on maximum likelihood scores. We show that the method produces trees with significantly better likelihood scores for fairly to highly divergent sequences. Yet, this improvement does not translate directly into an improvement of the tree and alignment quality.
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Martinson, Mattias. "Frames : Social Philosophy and Hermeneutics as Focal Points for Theology-Related Readings of Theodor W. Adorno's Critical Theory." Licentiate thesis, Uppsala University, Department of Theology, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-36241.
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Heinemann, Céline [Verfasser]. "Hygiene management in farm animal housing : Assessment of hygiene indicators and critical points in sanitation / Nina Céline Heinemann." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1240761236/34.
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Born, Stefan [Verfasser]. "Critical point theory for symmetries with fixed points = Theorie kritischer Punkte für Symmetrien mit Fixpunkten [[Elektronische Ressource]] / Stefan Born." Gießen : Universitätsbibliothek, 2011. http://d-nb.info/1063111242/34.
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Dokchan, Rakporn [Verfasser], R. [Akademischer Betreuer] März, W. [Akademischer Betreuer] Römisch, and E. [Akademischer Betreuer] Weinmüller. "Numerical integration of differential-algebraic equations with harmless critical points / Rakporn Dokchan. Gutachter: R. März ; W. Römisch ; E. Weinmüller." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2011. http://d-nb.info/1015046657/34.
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