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University of Nottingham
1.
Weston, Caron Olivene.
An examination of the place of school mathematics in preparing pupils for the workplace in Antigua and Barbuda.
Degree: PhD, 2014, University of Nottingham
URL: http://eprints.nottingham.ac.uk/27824/ 
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.647500
► This research examines the preparation made to enable mathematics teachers to appropriately prepare school leavers entering directly into the workforce upon graduation to handle the…
(more)
▼ This research examines the preparation made to enable mathematics teachers to appropriately prepare school leavers entering directly into the workforce upon graduation to handle the different branches of mathematics. The methodology was that of the interpretive qualitative paradigm. The method was that of the multi method case study and the tools included: constructed conversation; interviews; telephone calls; email; focus group; photography; video recording; participatory observation; observation and documentation. The theoretical framework was informed by components of the Engeström (2001) second generation model. The study found that while there was hardly any preparation made in the system to accommodate mathematics teachers in the appropriate preparation of students to cope with rapid changes in technology and mathematical skills in the workplace, because of on-the-job training, the newly employed were able to handle the mathematics at their workplaces. Additionally, the technological tools in use at workplaces allowed employees to handle the mathematics in work: complicated algorithms associated with mathematical operations were hidden in these technological tools. Employees were then only required to perform an operation of a push or a pull of a button (switch) to turn on or to turn off the device. Equally, mathematical knowledge at the workplace was an activity; thus there was no need for the pedagogical format required for school mathematics classes. This research is significant since this is the first of its kind in the Caribbean using components of the Engeström (2001) second generation model as its theoretical framework and for examination of the mathematics informing workplaces in Antigua and Barbuda. It has also served to bridge a gap between school teachers and employers on communication of the different branches of mathematics required in the workplaces of Antigua and Barbuda. Simultaneously it represents a new block in the wall of literature from scholars in the field of workplace mathematics since the Caribbean’s space was empty.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Weston, C. O. (2014). An examination of the place of school mathematics in preparing pupils for the workplace in Antigua and Barbuda. (Doctoral Dissertation). University of Nottingham. Retrieved from http://eprints.nottingham.ac.uk/27824/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.647500
Chicago Manual of Style (16th Edition):
Weston, Caron Olivene. “An examination of the place of school mathematics in preparing pupils for the workplace in Antigua and Barbuda.” 2014. Doctoral Dissertation, University of Nottingham. Accessed October 23, 2017.
http://eprints.nottingham.ac.uk/27824/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.647500.
MLA Handbook (7th Edition):
Weston, Caron Olivene. “An examination of the place of school mathematics in preparing pupils for the workplace in Antigua and Barbuda.” 2014. Web. 23 Oct 2017.
Vancouver:
Weston CO. An examination of the place of school mathematics in preparing pupils for the workplace in Antigua and Barbuda. [Internet] [Doctoral dissertation]. University of Nottingham; 2014. [cited 2017 Oct 23].
Available from: http://eprints.nottingham.ac.uk/27824/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.647500.
Council of Science Editors:
Weston CO. An examination of the place of school mathematics in preparing pupils for the workplace in Antigua and Barbuda. [Doctoral Dissertation]. University of Nottingham; 2014. Available from: http://eprints.nottingham.ac.uk/27824/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.647500
University of Warwick
2.
Ali, Adnan.
Stochastic pattern formation in growth models with spatial competition.
Degree: PhD, 2012, University of Warwick
URL: http://wrap.warwick.ac.uk/54323/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574996
► The field of stochastic growth encompasses various different processes which are ubiquitously seen across the physical world. In many systems, stochasticity appears quite naturally, where…
(more)
▼ The field of stochastic growth encompasses various different processes which are ubiquitously seen across the physical world. In many systems, stochasticity appears quite naturally, where inherent randomness provides the right setting for the tone of motion and interaction, whose symphony leads to the surprising emergence of interesting patterns and structure. Although on the microscopic scale one can be overwhelmed by the randomness arising from the fluctuating interactions between components, on the macroscopic scale, however, one is mesmerized by the emergence of mathematical beauty and symmetry, leading to complex structures with fractal architecture. Competition between components adds an extra degree of complexity and leads to the possibility of critical behaviour and phase transitions. It is an important aspect of many systems, and in order to provide a full explanation of many natural phenomena, we have to understand the role it plays on modifying behaviour. The combination of stochastic growth and competition leads to the emergence of interesting complex patterns. They occur in various systems and in many forms, and thus we treat competition in growth models driven by different laws for the stochastic noise. As a consequence our results are widely applicable and we encourage the reader to find good use for them in their respective field. In this thesis we study stochastic systems containing interacting particles whose motion and interplay lead to directed growth structures on a particular geometry. We show how the effect of the overall geometry in many growth processes can be captured elegantly in terms of a time dependent metric. A natural example we treat is isoradial growth in two dimensions, with domain boundaries of competing microbial species as an example of a system with a homogeneously changing metric. In general, we view domain boundaries as space-time trajectories of particles moving on a dynamic surface and map those into more easily tractable systems with constant metric. This leads to establishing a generic relation between locally interacting, scale invariant stochastic space-time trajectories under constant and time dependent metric. Indeed “the book of nature is written in the language of mathematics” (Galileo Galilei) and we provide a mathematical framework for various systems with various interactions and our results are backed with numerical confirmation.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Ali, A. (2012). Stochastic pattern formation in growth models with spatial competition. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/54323/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574996
Chicago Manual of Style (16th Edition):
Ali, Adnan. “Stochastic pattern formation in growth models with spatial competition.” 2012. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/54323/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574996.
MLA Handbook (7th Edition):
Ali, Adnan. “Stochastic pattern formation in growth models with spatial competition.” 2012. Web. 23 Oct 2017.
Vancouver:
Ali A. Stochastic pattern formation in growth models with spatial competition. [Internet] [Doctoral dissertation]. University of Warwick; 2012. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/54323/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574996.
Council of Science Editors:
Ali A. Stochastic pattern formation in growth models with spatial competition. [Doctoral Dissertation]. University of Warwick; 2012. Available from: http://wrap.warwick.ac.uk/54323/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574996
City University London
3.
Lloyd, Thomas.
Advancing integrability for strings in AdS3/CFT2.
Degree: PhD, 2016, City University London
URL: http://openaccess.city.ac.uk/14883/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687749
► In this thesis we develop techniques of integrability in the study of dualities between two-dimensional conformal field theories and theories of closed strings on three-dimensional…
(more)
▼ In this thesis we develop techniques of integrability in the study of dualities between two-dimensional conformal field theories and theories of closed strings on three-dimensional Anti-de Sitter background geometries. For several years after integrability was first applied to the 3d/2d dualities, it was an unanswered question how to incorporate the so-called \massless modes" of these theories into the integrability machinery. Here we tackle this problem in several contexts. We show that in the classical integrable description of closed strings the implementation of the string Virasoro constraints needs to be modified for geometries with multiple factors where massless modes are present. We show further that with the correct implementation of the Virasoro constraints, massless modes can be included in integrability techniques for obtaining quantum corrections to physical quantities such as the energies of string solutions. Lastly, we consider the scattering of fundamental string excitations and derive all-loop expressions for the scattering matrix that includes both massless and massive excitations.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Lloyd, T. (2016). Advancing integrability for strings in AdS3/CFT2. (Doctoral Dissertation). City University London. Retrieved from http://openaccess.city.ac.uk/14883/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687749
Chicago Manual of Style (16th Edition):
Lloyd, Thomas. “Advancing integrability for strings in AdS3/CFT2.” 2016. Doctoral Dissertation, City University London. Accessed October 23, 2017.
http://openaccess.city.ac.uk/14883/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687749.
MLA Handbook (7th Edition):
Lloyd, Thomas. “Advancing integrability for strings in AdS3/CFT2.” 2016. Web. 23 Oct 2017.
Vancouver:
Lloyd T. Advancing integrability for strings in AdS3/CFT2. [Internet] [Doctoral dissertation]. City University London; 2016. [cited 2017 Oct 23].
Available from: http://openaccess.city.ac.uk/14883/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687749.
Council of Science Editors:
Lloyd T. Advancing integrability for strings in AdS3/CFT2. [Doctoral Dissertation]. City University London; 2016. Available from: http://openaccess.city.ac.uk/14883/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687749
City University London
4.
King, Oliver.
The representation theory of diagram algebras.
Degree: PhD, 2014, City University London
URL: http://openaccess.city.ac.uk/5915/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633609
► In this thesis we study the modular representation theory of diagram algebras, in particular the Brauer and partition algebras, along with a brief consideration of…
(more)
▼ In this thesis we study the modular representation theory of diagram algebras, in particular the Brauer and partition algebras, along with a brief consideration of the Temperley-Lieb algebra. The representation theory of these algebras in characteristic zero is well understood, and we show that it can be described through the action of a reflection group on the set of simple modules (a result previously known for the Temperley-Lieb and Brauer algebras). By considering the action of the corresponding affine reflection group, we give a characterisation of the (limiting) blocks of the Brauer and partition algebras in positive characteristic. In the case of the Brauer algebra, we then show that simple reflections give rise to non-zero decomposition numbers. We then restrict our attention to a particular family of Brauer and partition algebras, and use the block result to determine the entire decomposition matrix of the algebras therein.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
King, O. (2014). The representation theory of diagram algebras. (Doctoral Dissertation). City University London. Retrieved from http://openaccess.city.ac.uk/5915/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633609
Chicago Manual of Style (16th Edition):
King, Oliver. “The representation theory of diagram algebras.” 2014. Doctoral Dissertation, City University London. Accessed October 23, 2017.
http://openaccess.city.ac.uk/5915/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633609.
MLA Handbook (7th Edition):
King, Oliver. “The representation theory of diagram algebras.” 2014. Web. 23 Oct 2017.
Vancouver:
King O. The representation theory of diagram algebras. [Internet] [Doctoral dissertation]. City University London; 2014. [cited 2017 Oct 23].
Available from: http://openaccess.city.ac.uk/5915/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633609.
Council of Science Editors:
King O. The representation theory of diagram algebras. [Doctoral Dissertation]. City University London; 2014. Available from: http://openaccess.city.ac.uk/5915/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633609
City University London
5.
Malekpoor, Somayeh.
Optimization methods for deadbeat control design : a state space approach.
Degree: PhD, 2016, City University London
URL: http://openaccess.city.ac.uk/14396/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683774
► This thesis addresses the synthesis problem of state deadbeat regulator using state space techniques. Deadbeat control is a linear control strategy in discrete time systems…
(more)
▼ This thesis addresses the synthesis problem of state deadbeat regulator using state space techniques. Deadbeat control is a linear control strategy in discrete time systems and consists of driving the system from any arbitrary initial state to a desired final state infinite number of time steps. Having described the framework for development of the thesis which is in the form of a lower linear-fractional transformation (LFT), the conditions for internal stability based on the notion of coprime factorization over the set of proper and stable transfer matrices, namely RH, is discussed. This leads to the derivation of the class of all stabilizing linear controllers, which are parameterized affinely in terms of a stable but otherwise free parameter Q, usually known as the Q-parameterization. In this work, the classical Q- parameterization is generalized to deliver a parameterization for the family of deadbeat regulators. Time response characteristics of the deadbeat system are investigated. In particular, the deadbeat regulator design problem in which the system must satisfy time domain specifications and minimize a quadratic (LQG-type) performance criterion is examined. It is shown that the attained parameterization for deadbeat controllers leads to the formulation of the synthesis problem in a quadratic programming framework with Q regarded as the design variable. The equivalent formulation of this objective as a quadratic integral in the frequency domain provides the means for shaping the frequency response characteristics of the system. Using the LMI characterization of the standard H problem, a new scheme for shaping the system frequency response characteristics by minimizing the infinity norm of an appropriate closed-loop transfer function is introduced. As shown, the derived parameterization of deadbeat compensators simplifies considerably the formulation and solution of this problem. The last part of the work described in this thesis is devoted to addressing the synthesis problem of deadbeat regulators in a robust way, when the plant is subject to structured norm-bounded parametric uncertainties. A novel approach which is expressed as an LMI feasibility condition has been proposed and analysed.
Subjects/Keywords: QA Mathematics
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APA ·
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Manager
APA (6th Edition):
Malekpoor, S. (2016). Optimization methods for deadbeat control design : a state space approach. (Doctoral Dissertation). City University London. Retrieved from http://openaccess.city.ac.uk/14396/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683774
Chicago Manual of Style (16th Edition):
Malekpoor, Somayeh. “Optimization methods for deadbeat control design : a state space approach.” 2016. Doctoral Dissertation, City University London. Accessed October 23, 2017.
http://openaccess.city.ac.uk/14396/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683774.
MLA Handbook (7th Edition):
Malekpoor, Somayeh. “Optimization methods for deadbeat control design : a state space approach.” 2016. Web. 23 Oct 2017.
Vancouver:
Malekpoor S. Optimization methods for deadbeat control design : a state space approach. [Internet] [Doctoral dissertation]. City University London; 2016. [cited 2017 Oct 23].
Available from: http://openaccess.city.ac.uk/14396/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683774.
Council of Science Editors:
Malekpoor S. Optimization methods for deadbeat control design : a state space approach. [Doctoral Dissertation]. City University London; 2016. Available from: http://openaccess.city.ac.uk/14396/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683774
City University London
6.
Wang, Jinghua.
A hybrid model for large scale simulation of unsteady nonlinear waves.
Degree: PhD, 2016, City University London
URL: http://openaccess.city.ac.uk/14575/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685582
► A hybrid model for simulating rogue waves in random seas on a large time and space scale is proposed in this thesis. It is formed…
(more)
▼ A hybrid model for simulating rogue waves in random seas on a large time and space scale is proposed in this thesis. It is formed by combining the derived fifth order Enhanced Nonlinear Schrödinger Equation based on Fourier transform (ENLSE-5F), the fully nonlinear Enhanced Spectral Boundary Integral (ESBI) method and its simplified version. The numerical techniques and algorithm for coupling three models on time scale are provided. Using them, and the switch between the three models during the computation is triggered automatically according to wave nonlinearities. Numerical tests are carried out and the results indicate that this hybrid model could simulate rogue waves both accurately and efficiently. In some cases showed, the hybrid model is more than 10 times faster than just using the ESBI method.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
Wang, J. (2016). A hybrid model for large scale simulation of unsteady nonlinear waves. (Doctoral Dissertation). City University London. Retrieved from http://openaccess.city.ac.uk/14575/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685582
Chicago Manual of Style (16th Edition):
Wang, Jinghua. “A hybrid model for large scale simulation of unsteady nonlinear waves.” 2016. Doctoral Dissertation, City University London. Accessed October 23, 2017.
http://openaccess.city.ac.uk/14575/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685582.
MLA Handbook (7th Edition):
Wang, Jinghua. “A hybrid model for large scale simulation of unsteady nonlinear waves.” 2016. Web. 23 Oct 2017.
Vancouver:
Wang J. A hybrid model for large scale simulation of unsteady nonlinear waves. [Internet] [Doctoral dissertation]. City University London; 2016. [cited 2017 Oct 23].
Available from: http://openaccess.city.ac.uk/14575/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685582.
Council of Science Editors:
Wang J. A hybrid model for large scale simulation of unsteady nonlinear waves. [Doctoral Dissertation]. City University London; 2016. Available from: http://openaccess.city.ac.uk/14575/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685582
University of Glasgow
7.
Almahmud, Reem Abdullah J.
Wavelengths in bioconvection patterns.
Degree: PhD, 2016, University of Glasgow
URL: http://theses.gla.ac.uk/7834/
► Unicellular bottom-heavy swimming microorganisms are usually denser than the fluid in which they swim. In shallow suspensions, the bottom heaviness results in a gravitational torque…
(more)
▼ Unicellular bottom-heavy swimming microorganisms are usually denser than the fluid in which they swim. In shallow suspensions, the bottom heaviness results in a gravitational torque that orients the cells to swim vertically upwards in the absence of fluid flow. Swimming cells thus accumulate at the upper surface to form a concentrated layer of cells. When the cell concentration is high enough, the layer overturns to form bioconvection patterns. Thin concentrated plumes of cells descend rapidly and cells return to the upper surface in wide, slowly moving upwelling plumes. When there is fluid flow, a second viscous torque is exerted on the swimming cells. The balance between the local shear flow viscous and the gravitational torques determines the cells' swimming direction, (gyrotaxis). In this thesis, the wavelengths of bioconvection patterns are studied experimentally as well as theoretically as follow;
First, in aquasystem it is rare to find one species lives individually and when they swim they can form complex patterns. Thus, a protocol for controlled experiments to mix two species of swimming algal cells of \emph{C. rienhardtii} and \emph{C. augustae} is systematically described and images of bioconvection patterns are captured. A method for analysing images using wavelets and extracting the local dominant wavelength in spatially varying patterns is developed. The variation of the patterns as a function of the total concentration and the relative concentration between two species is analysed.
Second, the linear stability theory of bioconvection for a suspension of two mixed species is studied. The dispersion relationship is computed using Fourier modes in order to calculate the neutral curves as a function of wavenumbers k and m. The neutral curves are plotted to compare the instability onset of the suspension of the two mixed species with the instability onset of each species individually. This study could help us to understand which species contributes the most in the process of pattern formation.
Finally, predicting the most unstable wavelength was studied previously around a steady state equilibrium situation. Since assuming steady state equilibrium contradicts with reality, the pattern formation in a layer of finite depth of an evolving basic state is studied using the nonnormal modes approach. The nonnormal modes procedure identifies the optimal initial perturbation that can be obtained for a given time t as well as a given set of parameters and wavenumber k. Then, we measure the size of the optimal perturbation as it grows with time considering a range of wavenumbers for the same set of parameters to be able to extract the most unstable wavelength.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
Almahmud, R. A. J. (2016). Wavelengths in bioconvection patterns. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/7834/
Chicago Manual of Style (16th Edition):
Almahmud, Reem Abdullah J. “Wavelengths in bioconvection patterns.” 2016. Doctoral Dissertation, University of Glasgow. Accessed October 23, 2017.
http://theses.gla.ac.uk/7834/.
MLA Handbook (7th Edition):
Almahmud, Reem Abdullah J. “Wavelengths in bioconvection patterns.” 2016. Web. 23 Oct 2017.
Vancouver:
Almahmud RAJ. Wavelengths in bioconvection patterns. [Internet] [Doctoral dissertation]. University of Glasgow; 2016. [cited 2017 Oct 23].
Available from: http://theses.gla.ac.uk/7834/.
Council of Science Editors:
Almahmud RAJ. Wavelengths in bioconvection patterns. [Doctoral Dissertation]. University of Glasgow; 2016. Available from: http://theses.gla.ac.uk/7834/
University of Greenwich
8.
Rodney, Demane O'Neil.
An investigation of multilevel refinement in routing and location problems.
Degree: phd, School of Computing and Mathematical Sciences, 2008, University of Greenwich
URL: http://gala.gre.ac.uk/8199/
► Multilevel refinement is a collaborative hierarchical solution technique. The multilevel technique aims to enhance the solution process of optimisation problems by improving the asymptotic convergence…
(more)
▼ Multilevel refinement is a collaborative hierarchical solution technique. The multilevel technique aims to enhance the solution process of optimisation problems by improving the asymptotic convergence in the quality of solutions produced by its underlying local search heuristics and/or improving the convergence rate of these heuristics. To these aims, the central methodologies of the multilevel technique are filtering solutions from the search space (via coarsening), reducing the amount of problem detail considered at each level of the solution process and providing a mechanism to the underlying local search heuristics for efficiently making large moves around the search space. The neighbourhoods accessible by these moves are typically inaccessible if the local search heuristics are applied to the un-coarsened problems. The methodologies combine to meet the multilevel technique's aims, because, as the multilevel technique iteratively coarsens, extends and refines a given problem, it reduces the possibility of the local search heuristic becoming trapped in local optima of poor quality.
The research presented in this thesis investigates the application of multilevel refinement to classes of location and routing problems and develops numerous multilevel algorithms. Some of these algorithms are collaborative techniques for metaheuristics and others are collaborative techniques for local search heuristics. Additionally, new methods of coarsening for location and routing problems and enhancements for the multilevel technique are developed. It is demonstrated that the multilevel technique is suited to a wide array of problems. By extending the investigations of the multilevel technique across routing and location problems, the research was able to present generalisations regarding the multilevel technique's suitability, for these and similar types of problems.
Finally, results on a number of well known benchmarking suites for location and routing problem are presented, comparing equivalent single-level and multilevel algorithms. These results demonstrate that the multilevel technique provides significant gains over its single-level counterparts. In all cases, the multilevel algorithm was able to improve the asymptotic convergence in the quality of solutions produced by the standard (single-level) local search heuristics or metaheuristics. The multilevel technique did not improve the convergence rate of the single-level's local search heuristics in all cases. However, for large-scale problems the multilevel variants scaled in a manner superior to the single-level techniques. The research also demonstrated that for sufficiently large problems, the multilevel technique was able to improve the asymptotic convergence in the quality of solutions at a sufficiently fast rate, such that the multilevel algorithms were able to produce superior results compared to the single-level versions, without refining the solution down to the most detailed level.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Rodney, D. O. (2008). An investigation of multilevel refinement in routing and location problems. (Doctoral Dissertation). University of Greenwich. Retrieved from http://gala.gre.ac.uk/8199/
Chicago Manual of Style (16th Edition):
Rodney, Demane O'Neil. “An investigation of multilevel refinement in routing and location problems.” 2008. Doctoral Dissertation, University of Greenwich. Accessed October 23, 2017.
http://gala.gre.ac.uk/8199/.
MLA Handbook (7th Edition):
Rodney, Demane O'Neil. “An investigation of multilevel refinement in routing and location problems.” 2008. Web. 23 Oct 2017.
Vancouver:
Rodney DO. An investigation of multilevel refinement in routing and location problems. [Internet] [Doctoral dissertation]. University of Greenwich; 2008. [cited 2017 Oct 23].
Available from: http://gala.gre.ac.uk/8199/.
Council of Science Editors:
Rodney DO. An investigation of multilevel refinement in routing and location problems. [Doctoral Dissertation]. University of Greenwich; 2008. Available from: http://gala.gre.ac.uk/8199/
University of Greenwich
9.
Lebon, Gerard Serge Bruno.
Unstructured finite volume algorithms for compressible multiphase flow.
Degree: phd, School of Computing and Mathematical Sciences, 2011, University of Greenwich
URL: http://gala.gre.ac.uk/8077/
► This research presents novel algorithms for computing flow within an unstructured, collocated, finite volume solver in the presence of non-orthogonality and compressibility in order to…
(more)
▼ This research presents novel algorithms for computing flow within an unstructured, collocated, finite volume solver in the presence of non-orthogonality and compressibility in order to extend the range of problems which can be modelled with the University's in-house CFD code: PHYSICA.
A new non-orthogonality diffusion correction relaxation parameter has been successfully introduced and tested with benchmarks from the literature. Cases involving geometries meshed with commercial packages have been successfully run with the diffusion correction methods, variable bounding and proper under-relaxation practices. The applicability of a pressure interpolation method has also been tested with these cases.
A procedure for solving compressible flow within a finite volume, pressure correction type scheme, has been devised and successfully implemented in different test cases. This method is however prone to numerical diffusion in the presence of shocks, but does work even in the presence of skewed meshes. The method was then tested with the case of an oxygen jet entering a heated furnace, for which experimental data is available for comparison. The method was successful in predicting the axial variables of the jet, and used to develop a turbulence modification model for such jets.
The method was finally used to model the deformation of a free surface impinged by a compressible jet, using a novel zonal method called zonal Gas And Liquid Analyser (GALA). Convergence was achieved with the method developed in this research, together with the application of the counter diffusion method to model the moving interface.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Lebon, G. S. B. (2011). Unstructured finite volume algorithms for compressible multiphase flow. (Doctoral Dissertation). University of Greenwich. Retrieved from http://gala.gre.ac.uk/8077/
Chicago Manual of Style (16th Edition):
Lebon, Gerard Serge Bruno. “Unstructured finite volume algorithms for compressible multiphase flow.” 2011. Doctoral Dissertation, University of Greenwich. Accessed October 23, 2017.
http://gala.gre.ac.uk/8077/.
MLA Handbook (7th Edition):
Lebon, Gerard Serge Bruno. “Unstructured finite volume algorithms for compressible multiphase flow.” 2011. Web. 23 Oct 2017.
Vancouver:
Lebon GSB. Unstructured finite volume algorithms for compressible multiphase flow. [Internet] [Doctoral dissertation]. University of Greenwich; 2011. [cited 2017 Oct 23].
Available from: http://gala.gre.ac.uk/8077/.
Council of Science Editors:
Lebon GSB. Unstructured finite volume algorithms for compressible multiphase flow. [Doctoral Dissertation]. University of Greenwich; 2011. Available from: http://gala.gre.ac.uk/8077/
University of Greenwich
10.
Rustogi, Kabir.
Machine scheduling with changing processing times and rate-modifying activities.
Degree: phd, School of Computing and Mathematical Sciences, 2013, University of Greenwich
URL: http://gala.gre.ac.uk/11992/
► In classical scheduling models, it is normally assumed that the processing times of jobs are fixed. However, in the recent years, there has been a…
(more)
▼ In classical scheduling models, it is normally assumed that the processing times of jobs are fixed. However, in the recent years, there has been a growing interest in models with variable processing times. Some of the common rationales provided for considering such models, is as follows: the machine conditions may deteriorate as more jobs are processed, resulting in higher than normal processing times, or conversely, the machine’s operator may gain more experience as more jobs are processed, so he/she can process the jobs faster. Another direction of improving the practical relevance of models is by introducing certain rate-modifying activities, such as maintenance periods, in the schedule.
In this thesis, we mainly focus on the study of integrated models which allow changing processing times and rate-modifying activities. When this project was started, it was felt that there was a major scope of improvement in the area, both in terms of creating more general, practically relevant models and developing faster algorithms that are capable of handling a wide variety of problems. In this thesis, we address both these issues.
We introduce several enhanced, practically relevant models for scheduling problems with changing times that allow various types of rate-modifying activities, various effects or a combination of effects on the processing times. To handle these generalised models, we developed a unified framework of algorithms that use similar general principles, through which, the effects of rate-modifying activities can be systematically studied for many different scenarios.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Rustogi, K. (2013). Machine scheduling with changing processing times and rate-modifying activities. (Doctoral Dissertation). University of Greenwich. Retrieved from http://gala.gre.ac.uk/11992/
Chicago Manual of Style (16th Edition):
Rustogi, Kabir. “Machine scheduling with changing processing times and rate-modifying activities.” 2013. Doctoral Dissertation, University of Greenwich. Accessed October 23, 2017.
http://gala.gre.ac.uk/11992/.
MLA Handbook (7th Edition):
Rustogi, Kabir. “Machine scheduling with changing processing times and rate-modifying activities.” 2013. Web. 23 Oct 2017.
Vancouver:
Rustogi K. Machine scheduling with changing processing times and rate-modifying activities. [Internet] [Doctoral dissertation]. University of Greenwich; 2013. [cited 2017 Oct 23].
Available from: http://gala.gre.ac.uk/11992/.
Council of Science Editors:
Rustogi K. Machine scheduling with changing processing times and rate-modifying activities. [Doctoral Dissertation]. University of Greenwich; 2013. Available from: http://gala.gre.ac.uk/11992/
The London School of Economics and Political Science (LSE)
11.
Abu-Khazneh, Ahmad.
Matchings and covers of multipartite hypergraphs.
Degree: phd, 2016, The London School of Economics and Political Science (LSE)
URL: http://etheses.lse.ac.uk/3360/
► Koenig’s theorem is a classic result in combinatorics which states that for every bipartite graph G, the cover number of G (denoted by τ (G))…
(more)
▼ Koenig’s theorem is a classic result in combinatorics which states that for every bipartite graph G, the cover number of G (denoted by τ (G)) is equal to its matching number (denoted by ν(G)). The theorem’s importance stems from its many applications in various areas of mathematics, such as optimisation theory and algorithmic analysis.
Ryser’s Conjecture for multipartite hypergraphs is a proposed generalisation of Koenig’s theorem made in the 1970s. It asserts that for every r-partite hypergraph H, we have the following inequality: τ (H) ≤ (r − 1)ν(H). The conjecture is only known to be true for tripartite hypergraphs and a few other special cases.
In the first part of this thesis, we present algorithms that – for a given r – are able to prove or disprove the conjecture in the case of r-partite intersecting hypergraphs. Moreover, for a given r, the algorithms can also be used to enumerate all r-partite extremal hypergraphs to Ryser’s Conjecture. Extremal hypergraphs are r-partite hypergraphs for which the cover number is exactly r − 1 times the matching number.
The second part of this thesis focuses on the case of 4-partite hypergraphs. It is motivated by a recent result on Ryser’s Conjecture for tripartite hypergraphs. The result classifies all tripartite extremal hypergraphs, and implies that if H is a tripartite extremal hypergraph, then it must contain ν(H) vertex-disjoint tripartite intersecting extremal hypergraphs.
This result leads to the natural question of whether a similar characterisation of r-partite extremal hypergraphs is possible for other values of r? In particular, for the first open case of Ryser’s Conjecture, the case of r = 4.
We shed some light on this question, by first classifying all 4-partite intersecting extremal hypergraphs. We then present a list of 4-partite extremal hypergraphs with matching number equal to two, such that none of them contain two vertex-disjoint 4-partite extremal hypergraphs.
Our result shows that a straightforward characterisation of 4-partite extremal hypergraphs is not possible in terms of vertex-disjoint intersecting extremal hypergraphs. However, we still conjecture an analogue to the classification of tripartite extremal hypergraphs, which is not contradicted by our extremal examples.
In the final part of the thesis we focus on intersecting extremal hypergraphs to Ryser’s Conjecture. Apart from a few sporadic constructions in the literature, there is only one known family of r-partite extremal hypergraphs, which comes from finite projective planes. The family contains an r-partite extremal hypergraph to Ryser’s Conjecture, whenever a finite projective plane of order r − 1 exists.
Our contribution is to first calculates bounds on the sparsest possible extremal hypergraphs for small values of r. We then prove the existence of a new family of extremal hypergraphs to Ryser’s Conjecture.
The new family contains an r-partite intersecting extremal hypergraph to Ryser’s Conjecture, whenever a finite projective plane of order r − 2 exists. Moreover we are able to…
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Abu-Khazneh, A. (2016). Matchings and covers of multipartite hypergraphs. (Doctoral Dissertation). The London School of Economics and Political Science (LSE). Retrieved from http://etheses.lse.ac.uk/3360/
Chicago Manual of Style (16th Edition):
Abu-Khazneh, Ahmad. “Matchings and covers of multipartite hypergraphs.” 2016. Doctoral Dissertation, The London School of Economics and Political Science (LSE). Accessed October 23, 2017.
http://etheses.lse.ac.uk/3360/.
MLA Handbook (7th Edition):
Abu-Khazneh, Ahmad. “Matchings and covers of multipartite hypergraphs.” 2016. Web. 23 Oct 2017.
Vancouver:
Abu-Khazneh A. Matchings and covers of multipartite hypergraphs. [Internet] [Doctoral dissertation]. The London School of Economics and Political Science (LSE); 2016. [cited 2017 Oct 23].
Available from: http://etheses.lse.ac.uk/3360/.
Council of Science Editors:
Abu-Khazneh A. Matchings and covers of multipartite hypergraphs. [Doctoral Dissertation]. The London School of Economics and Political Science (LSE); 2016. Available from: http://etheses.lse.ac.uk/3360/
Cardiff University
12.
Vronskaya, Maria.
Stability of singular spectrum analysis and causality in time series.
Degree: PhD, 2013, Cardiff University
URL: http://orca.cf.ac.uk/52140/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585280
► The concept of causality has been widely studied in econometrics and statistics since 1969, when C. J. Granger published his paper "Investigating causal relations by…
(more)
▼ The concept of causality has been widely studied in econometrics and statistics since 1969, when C. J. Granger published his paper "Investigating causal relations by econometric models and cross-spectral methods". The intuitive basis for his definition of causality is the following: time series Y is causing time series X if the use of the additional information provided by Y improves the forecast of series X. In the present thesis we focus on combining Granger's causality concept with the Singular Spectrum Analysis (SSA) technique. SSA is founded on the idea of transforming the time series into a multidimensional trajectory form (Hankel matrices), Singular Value Decomposition with subsequent projection to a lower-dimensional subspace and diagonal averaging. The main aim of the present thesis is to study the causality concept through SSA prism in details and suggest a novel causality measure, which can be used outside the stationary autoregressive class, which is the framework for Granger's original causality concept. We first apply standard statistical tests directly to simulated data to assess the improvement of forecast quality of bivariate multidimensional SSA (MSSA) of time series X and Y compared with SSA of time series X only. Although the results of performance of these tests are reasonably conclusive, the simulation method is time consuming and, thus, more theoretical understanding is desirable. We solve a fundamental scaling problem of the MSSA approach by introducing so-called linearized MSSA. The linearized MSSA approach shows a way towards a causality measure, calculated from the forecast linear recurrence formula (LRF) coefficients. We finally analyze SSA and (non-linear) bivariate MSSA approach in terms of first order stability analysis under perturbations leading to the construction of a valid suitable measure of causality. The construction of the measure requires some simplifying assumptions in the stability analysis whose validity we verify for both simulated and real data.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Vronskaya, M. (2013). Stability of singular spectrum analysis and causality in time series. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/52140/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585280
Chicago Manual of Style (16th Edition):
Vronskaya, Maria. “Stability of singular spectrum analysis and causality in time series.” 2013. Doctoral Dissertation, Cardiff University. Accessed October 23, 2017.
http://orca.cf.ac.uk/52140/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585280.
MLA Handbook (7th Edition):
Vronskaya, Maria. “Stability of singular spectrum analysis and causality in time series.” 2013. Web. 23 Oct 2017.
Vancouver:
Vronskaya M. Stability of singular spectrum analysis and causality in time series. [Internet] [Doctoral dissertation]. Cardiff University; 2013. [cited 2017 Oct 23].
Available from: http://orca.cf.ac.uk/52140/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585280.
Council of Science Editors:
Vronskaya M. Stability of singular spectrum analysis and causality in time series. [Doctoral Dissertation]. Cardiff University; 2013. Available from: http://orca.cf.ac.uk/52140/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585280
University of Glasgow
13.
Hao, Yujue.
Solving Eigenproblems with application in collapsible channel flows.
Degree: PhD, 2013, University of Glasgow
URL: http://theses.gla.ac.uk/4589/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.586757
► Collapsible channel flows have been attracting the interest of many researchers, because of the physiological applications in the cardiovascular system, the respiratory system and urinary…
(more)
▼ Collapsible channel flows have been attracting the interest of many researchers, because of the physiological applications in the cardiovascular system, the respiratory system and urinary system. The linear stability analysis of the collapsible channel flows in the Fluid-Beam Model can be finalized as a large sparse asymmetric generalized eigenvalue problem, where the stiffness matrix is sparse, asymmetric and nonsingular, and the mass matrix is sparse, asymmetric and singular. The dimensions of the both matrices can reach about ten thousand or more, and the traditional QZ Algorithm is so expensive for this size of eigenvalue problem, due to its large requirement of computational resources and the quite long elapsed time. Unlike the traditional direct methods, the projection methods are much more efficient for solving some specified eigenpairs of the large scale eigenvalue problems, because normally a small subspace is made use of, and the original eigenvalue problem is projected to this small subspace. With this projection, the size of the eigenvalue problem is reduced significantly, and then the small dimensional eigenvalue problem can be easily and rapidly worked out by employing a traditional solver. Combined with a restarting strategy, this can be used to solve large dimensional eigenvalue problem much more rapidly and precisely. So far as we know, the Implicitly Restarted Arnoldi iteration(IRA) is considered as one of the most effective asymmetric eigenvalue solvers. In order to improve the efficiency of linear stability analysis in collapsible channel flows, an IRA method is employed to the linear stability analysis of collapsible channel flows in FBM. A Frontal Solver, which is an efficient solver of large sparse linear system, is also used to replace the process of shift-and-invert transformation. After applying these two efficient solvers, the new eigenvalue solver of collapsible channel flows – Arnoldi method with a Frontal Solver(AR-F), not only gets rid of the restriction of memory storage, but also reduces the computational time observably. Some validating and testing work have been done to variety of meshes. The AR-F can solve the eigenvalues with largest real parts very quickly, and can also solve the large scale eigenvalue problems, which cannot be solved by the QZ Algorithm, whose results have been proved to be correct with the unsteady simulations. Compared with the traditional QZ Algorithm, not only a great deal of elapsed time is saved, but also the increasing rate of the operation numbers is dropped to O(n) from O(n3) of QZ Algorithm. With the powerful AR-F, the stability problems of refined meshes in collapsible channel flows are no long a barrier to the study. So AR-F is used to solve the eigenvalue problems from two refined meshes of the two different boundary conditions(pressure-driven system and flow-driven system), and the two neutral curves obtained are both revised and extended. This is the first time that IRA is made use of in the problem of fluid-structure interaction, and this is…
Subjects/Keywords: QA Mathematics
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APA ·
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Manager
APA (6th Edition):
Hao, Y. (2013). Solving Eigenproblems with application in collapsible channel flows. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/4589/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.586757
Chicago Manual of Style (16th Edition):
Hao, Yujue. “Solving Eigenproblems with application in collapsible channel flows.” 2013. Doctoral Dissertation, University of Glasgow. Accessed October 23, 2017.
http://theses.gla.ac.uk/4589/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.586757.
MLA Handbook (7th Edition):
Hao, Yujue. “Solving Eigenproblems with application in collapsible channel flows.” 2013. Web. 23 Oct 2017.
Vancouver:
Hao Y. Solving Eigenproblems with application in collapsible channel flows. [Internet] [Doctoral dissertation]. University of Glasgow; 2013. [cited 2017 Oct 23].
Available from: http://theses.gla.ac.uk/4589/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.586757.
Council of Science Editors:
Hao Y. Solving Eigenproblems with application in collapsible channel flows. [Doctoral Dissertation]. University of Glasgow; 2013. Available from: http://theses.gla.ac.uk/4589/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.586757
Cardiff University
14.
Holland, Jan W.
Properties of the operator product expansion in quantum field theory.
Degree: 2013, Cardiff University
URL: http://orca.cf.ac.uk/53230/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585305
► We prove that the operator product expansion (OPE), which is usually thought of as an asymptotic short distance expansion, actually converges at arbitrary finite distances…
(more)
▼ We prove that the operator product expansion (OPE), which is usually thought of as an asymptotic short distance expansion, actually converges at arbitrary finite distances within perturbative quantum field theory. The result is derived for the massive scalar field with \varphi4-interaction on Euclidean spacetime. This constitutes a generalisation of an earlier result by Hollands and Kopper, which states that the OPE of exactly two quantum fields converges. We also show that the OPE coefficients satisfy factorisation conditions for certain configurations of the spacetime arguments. Such conditions are known to encode information on the algebraic structure of the underlying quantum field theory. Both results rely on modified versions of the renormalisation group flow equations, which allow us to derive explicit bounds on the remainder of these expansions. Within this framework, we also derive a new formula for the perturbation of OPE coefficients, i.e. an equation relating coefficients at a given perturbation order to those of lower order. By iteration of this formula, a new constructive method for the computation of OPE coefficients in perturbation theory is obtained, which only requires the coefficients of the free theory as initial data. Finally, we investigate a strategy to restrict renormalisation ambiguities in quantum field theory via the condition that the OPE coefficients depend analytically on the coupling constant(s) of the respective model. We apply this strategy to the computation of the vacuum expectation value of the stress energy operator in the two dimensional Gross-Neveu model and we obtain a unique prediction for the non-perturbative contribution to this expectation value, which is of the order \exp(-2π/g2) (here g is the coupling constant). We discuss the possibility that a similar effect, if present in the Standard Model of particle physics, could account for the ''unnatural'' smallness of the cosmological constant.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Holland, J. W. (2013). Properties of the operator product expansion in quantum field theory. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/53230/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585305
Chicago Manual of Style (16th Edition):
Holland, Jan W. “Properties of the operator product expansion in quantum field theory.” 2013. Doctoral Dissertation, Cardiff University. Accessed October 23, 2017.
http://orca.cf.ac.uk/53230/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585305.
MLA Handbook (7th Edition):
Holland, Jan W. “Properties of the operator product expansion in quantum field theory.” 2013. Web. 23 Oct 2017.
Vancouver:
Holland JW. Properties of the operator product expansion in quantum field theory. [Internet] [Doctoral dissertation]. Cardiff University; 2013. [cited 2017 Oct 23].
Available from: http://orca.cf.ac.uk/53230/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585305.
Council of Science Editors:
Holland JW. Properties of the operator product expansion in quantum field theory. [Doctoral Dissertation]. Cardiff University; 2013. Available from: http://orca.cf.ac.uk/53230/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585305
15.
Hashem, Esamaldeen M. M. Husin.
Isomorphisms amongst certain classes of cyclically presented groups.
Degree: PhD, 2017, University of Essex
URL: http://repository.essex.ac.uk/20135/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.721381
► In this thesis we consider isomorphisms amongst certain classes of cyclically presented groups. We give isomorphism theorems for two families of cyclically presented groups, the…
(more)
▼ In this thesis we consider isomorphisms amongst certain classes of cyclically presented groups. We give isomorphism theorems for two families of cyclically presented groups, the groups Gn(h, k, p, q,r,s, l), and the groups G^εn(m, k, h), which were introduced by Cavicchioli, Repovs and Spaggiari. These families contain many subfamilies of cyclically presented groups, we have results for two of them, the groups Gn(m, k), which were introduced by Johnson and Mawdesley, and the groups Γn(k, l), which were introduced by Cavicchioli, Repovs and Spaggiari. The abelianization of the Fibonacci groups F(2, n) was proved by Lyndon to be finite and its order can be expressed in terms of the Lucas numbers. Bardakov and Vesnin have asked if there is a formula for the order of the abelianization of Gn(m, k) groups that can be expressed in terms of Fibonacci numbers. We produce formulas that compute the order of Gpm(x0xmx±1k)ab , Gpk(x0xmx±1k)ab for certain values of p where m, k are coprime, and for the groups Γn(1,n/2− 1)ab (this formula is given in terms of Lucas numbers). The values of the number of non-isomorphic Gn(m, k) groups was conjectured by Cavicchioli, O’Brien and Spaggiari for n = pl, where p is prime and l is a positive integer, we show that these values provide an upper bound for the number of non-isomorphic Gn(m, k) groups. We also give lower bounds and upper bounds for the number of non- isomorphic Gn(m, k) and Γn(k, l) groups for certain values of n. Similar to the investigation of the type of isomorphisms of Gn(m, k) groups for n ≤ 27 that was carried by Cavicchioli, O’Brien and Spaggiari, we perform a similar investigation for Γn(k, l) groups for n ≤ 29.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Hashem, E. M. M. H. (2017). Isomorphisms amongst certain classes of cyclically presented groups. (Doctoral Dissertation). University of Essex. Retrieved from http://repository.essex.ac.uk/20135/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.721381
Chicago Manual of Style (16th Edition):
Hashem, Esamaldeen M M Husin. “Isomorphisms amongst certain classes of cyclically presented groups.” 2017. Doctoral Dissertation, University of Essex. Accessed October 23, 2017.
http://repository.essex.ac.uk/20135/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.721381.
MLA Handbook (7th Edition):
Hashem, Esamaldeen M M Husin. “Isomorphisms amongst certain classes of cyclically presented groups.” 2017. Web. 23 Oct 2017.
Vancouver:
Hashem EMMH. Isomorphisms amongst certain classes of cyclically presented groups. [Internet] [Doctoral dissertation]. University of Essex; 2017. [cited 2017 Oct 23].
Available from: http://repository.essex.ac.uk/20135/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.721381.
Council of Science Editors:
Hashem EMMH. Isomorphisms amongst certain classes of cyclically presented groups. [Doctoral Dissertation]. University of Essex; 2017. Available from: http://repository.essex.ac.uk/20135/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.721381
16.
Alsoufi, Ghazwan.
Mathematical models of seaside operations in container ports and their solution.
Degree: PhD, 2017, University of Essex
URL: http://repository.essex.ac.uk/20013/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716730
► Operational Research and Optimization are fundamental disciplines which, for decades, provided the real-world with tools for solving practical problems. Many such problems arise in container…
(more)
▼ Operational Research and Optimization are fundamental disciplines which, for decades, provided the real-world with tools for solving practical problems. Many such problems arise in container ports. Container terminals are important assets in modern economies. They constitute an important means of distributing goods made overseas to domestic markets in most countries. They are expensive to build and difficult to operate. We describe here some of the main operations which are faced daily by decision makers at those facilities. Decision makers often use Operational Research and Optimization tools to run these operations effectively. In this thesis, we focus on seaside operations which can be divided into three main problems: 1- the Berth Allocation Problem (BAP), 2- the Quay Crane Assignment Problem (QCAP), 3- the Quay Crane Scheduling Problem (QCSP). Each one of the above is a complex optimization problem in its own right. However, solving them individually without the consideration of the others may lead to overall suboptimal solutions. For this reason we will investigate the pairwise combinations of these problems and their total integration In addition, several important factors that affected on the final solution. The main contributions of this study are modelling and solving of the: 1- Robust berth allocation problem (RBAP): a new efficient mathematical model is formulated and a hybrid algorithm based on Branch-and-Cut and the Genetic Algorithm is used to find optimal or near optimal solutions for large scale instances in reasonable time. 2- Quay crane assignment and quay crane scheduling problem (QCASP): a new mathematical model is built to simultaneously solve QCASP and a heuristic based on the Genetic Algorithm is developed to find solutions to realistic instances in reasonable time. 3- Berth allocation, quay crane assignment and quay crane scheduling problem (BACASP): an aggregate model for all three seaside operations is proposed and to solve realistic instances of the problem, an adapted variant of the Genetic Algorithm is implemented.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Alsoufi, G. (2017). Mathematical models of seaside operations in container ports and their solution. (Doctoral Dissertation). University of Essex. Retrieved from http://repository.essex.ac.uk/20013/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716730
Chicago Manual of Style (16th Edition):
Alsoufi, Ghazwan. “Mathematical models of seaside operations in container ports and their solution.” 2017. Doctoral Dissertation, University of Essex. Accessed October 23, 2017.
http://repository.essex.ac.uk/20013/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716730.
MLA Handbook (7th Edition):
Alsoufi, Ghazwan. “Mathematical models of seaside operations in container ports and their solution.” 2017. Web. 23 Oct 2017.
Vancouver:
Alsoufi G. Mathematical models of seaside operations in container ports and their solution. [Internet] [Doctoral dissertation]. University of Essex; 2017. [cited 2017 Oct 23].
Available from: http://repository.essex.ac.uk/20013/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716730.
Council of Science Editors:
Alsoufi G. Mathematical models of seaside operations in container ports and their solution. [Doctoral Dissertation]. University of Essex; 2017. Available from: http://repository.essex.ac.uk/20013/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716730
Cardiff University
17.
Symons, Frederick.
On uniqueness in some physical systems.
Degree: PhD, 2017, Cardiff University
URL: http://orca.cf.ac.uk/103772/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720919
► In this work we present some uniqueness and cloaking results for a related pair of inverse problems. The first concerns recovering the parameter q in…
(more)
▼ In this work we present some uniqueness and cloaking results for a related pair of inverse problems. The first concerns recovering the parameter q in a Bessel-type operator pencil, over L2(0, 1; rdr) from (a generalisation of) the Weyl–-Titchmarsh boundary m-function. We assume that both coefficients, w and q, are singular at 0. We prove q is uniquely determined by the sequence m(-n2) (n = 1, 2, 3, ...), using asymptotic and spectral analysis and m-function interpolation results. For corollary we find, in a halfdisc with a singular “Dirichlet-point” boundary condition on the straight edge, a singular radial Schroedinger potential is uniquely determined by Dirichlet-to- Neumann boundary measurements on the semi-circular edge. The second result concerns recovery of three things—a Schroedinger potential in a planar domain, a Dirichlet-point boundary condition on part of the boundary, and a self-adjointness-imposing condition—from Dirichlet-to-Neumann measurements on the remaining boundary. With modern approaches to the inverse conductivity problem and a solution-space density argument we show the boundary condition cloaks the potential and vice versa. Appealing to negative eigen-value asymptotics we find the full-frequency problem has full uniqueness.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Symons, F. (2017). On uniqueness in some physical systems. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/103772/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720919
Chicago Manual of Style (16th Edition):
Symons, Frederick. “On uniqueness in some physical systems.” 2017. Doctoral Dissertation, Cardiff University. Accessed October 23, 2017.
http://orca.cf.ac.uk/103772/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720919.
MLA Handbook (7th Edition):
Symons, Frederick. “On uniqueness in some physical systems.” 2017. Web. 23 Oct 2017.
Vancouver:
Symons F. On uniqueness in some physical systems. [Internet] [Doctoral dissertation]. Cardiff University; 2017. [cited 2017 Oct 23].
Available from: http://orca.cf.ac.uk/103772/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720919.
Council of Science Editors:
Symons F. On uniqueness in some physical systems. [Doctoral Dissertation]. Cardiff University; 2017. Available from: http://orca.cf.ac.uk/103772/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720919
University of Warwick
18.
Langham, Jacob.
Spiral pinballs, cardiac tissue and deforming capacitors.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/90330/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720514
► ‘Spiral pinballs’ are resonantly drifting spiral waves in excitable media that reflect from boundaries. Instead of reflecting at an angle equal to the one at…
(more)
▼ ‘Spiral pinballs’ are resonantly drifting spiral waves in excitable media that reflect from boundaries. Instead of reflecting at an angle equal to the one at which they approach the boundary—like a ray of light reflecting from a mirror—they reflect in a preferred direction. This invites comparison with a number of other complex systems that behave as nonspecular billiards, including bouncing droplets on a vibrated bath, swimming microorganisms and segments of chemical waves. In the first part of this thesis, we study the trajectories of spiral pinball reflections. A catalogue of interesting behaviours is discovered in both the small- and large-core rotation regimes and the long-term billiard dynamics is briefly considered. By using an asymptotic theory, we examine the reflection process in detail and thereby explain many of the observed phenomena. The second part of this thesis concerns itself with modelling spiral wave activity in a deforming medium. Our motivation stems from cardiac tissue, in which spiral waves and mechanical deformation are reciprocally coupled. We describe a simple modelling approach for this system and discuss its implementation. Various different results are presented using this model. Finally we consider a problem from the engineering world. Dielectric elastomers are flexible capacitors that undergo nonlinear elastic deformations in response to forces arising from electric surface charges. We propose a novel modelling approach that decomposes these forces into a compressive stress and a tangential shear. The tangential component corresponds to a fringing effect that is usually considered to be negligible. Via numerical simulations and comparison with experimental data we show that it nonetheless has an important role to play in selecting the deformed shapes that these systems adopt. In some cases, we are able to compute multiple equilibrium configurations and it is shown that doing so is necessary to obtain the most physically relevant states.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Langham, J. (2017). Spiral pinballs, cardiac tissue and deforming capacitors. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/90330/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720514
Chicago Manual of Style (16th Edition):
Langham, Jacob. “Spiral pinballs, cardiac tissue and deforming capacitors.” 2017. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/90330/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720514.
MLA Handbook (7th Edition):
Langham, Jacob. “Spiral pinballs, cardiac tissue and deforming capacitors.” 2017. Web. 23 Oct 2017.
Vancouver:
Langham J. Spiral pinballs, cardiac tissue and deforming capacitors. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/90330/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720514.
Council of Science Editors:
Langham J. Spiral pinballs, cardiac tissue and deforming capacitors. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/90330/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720514
University of Warwick
19.
Shukla, Abhishek.
Analysis of data assimilation schemes.
Degree: PhD, 2016, University of Warwick
URL: http://wrap.warwick.ac.uk/90880/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720479
► Data assimilation schemes are methods to estimate true underlying state of the physical systems of interest by combining the theoretical knowledge about the underlying system…
(more)
▼ Data assimilation schemes are methods to estimate true underlying state of the physical systems of interest by combining the theoretical knowledge about the underlying system with available observations of the state. However, in most of the physical systems the observations often are noisy and only partially available. In the first part of this thesis we study the case of sequential data assimilation scheme, when the underlying system is nonlinear chaotic and the observations are partial and noisy. We produce a rigorous and quantitative analysis of data assimilation process for fixed observation modes. We also introduce a novel method of dynamically rearranging observation modes, leading to the requirement of fewer observation modes while maintaining the accuracy of the data assimilation process. In the second part of the thesis we focus on 4DVAR data assimilation scheme which is a variational method. 4DVAR data assimilation is a method that solves a variational problem; given a set of observations and a numerical model for the underlying physical system together with a priori information on the initial condition to estimate the initial condition for the underlying model. We propose a hybrid data assimilation scheme where, we consider the 3DVAR scheme for the model as the constraint on the variational form, rather than constraining the variational form with the original model. We observe that this method reduces the computational cost of the minimization of the 4DVAR variational form, however, it introduces a bias in the estimate of the initial condition. We then explore how the results can be extended to weak constraint 4DVAR.
Subjects/Keywords: QA Mathematics
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APA ·
Chicago ·
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APA (6th Edition):
Shukla, A. (2016). Analysis of data assimilation schemes. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/90880/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720479
Chicago Manual of Style (16th Edition):
Shukla, Abhishek. “Analysis of data assimilation schemes.” 2016. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/90880/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720479.
MLA Handbook (7th Edition):
Shukla, Abhishek. “Analysis of data assimilation schemes.” 2016. Web. 23 Oct 2017.
Vancouver:
Shukla A. Analysis of data assimilation schemes. [Internet] [Doctoral dissertation]. University of Warwick; 2016. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/90880/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720479.
Council of Science Editors:
Shukla A. Analysis of data assimilation schemes. [Doctoral Dissertation]. University of Warwick; 2016. Available from: http://wrap.warwick.ac.uk/90880/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720479
University of Warwick
20.
Sammut, Fiona.
Using generalized linear models to model compositional response data.
Degree: PhD, 2016, University of Warwick
URL: http://wrap.warwick.ac.uk/89876/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720443
► This work proposes a multivariate logit model which models the influence of explanatory variables on continuous compositional response variables. This multivariate logit model generalizes an…
(more)
▼ This work proposes a multivariate logit model which models the influence of explanatory variables on continuous compositional response variables. This multivariate logit model generalizes an elegant method that was suggested previously by Wedderburn (1974) for the analysis of leaf blotch data in the special case of J = 2, leading to our naming this new approach as the generalized Wedderburn method. In contrast to the logratio modelling approach devised by Aitchison (1982, J. Roy Stat. Soc. B.), the multivariate logit model used under the generalized Wedderburn approach models the expectation of a compositional response variable directly and is also able to handle zeros in the data. The estimation of the parameters in the new model is carried out using the technique of generalized estimating equations (GEE). This technique relies on the specification of a working variance-covariance structure. A working variance-covariance structure which caters for the specific variability arising in compositional data is derived. The GEE estimator that is used to estimate the parameters of the multivariate logit model is shown to be invariant to the values of the correlation and dispersion parameters in the working variance-covariance structure. Due to this invariance property and the fact that the estimating equations used under the generalized Wedderburn method are linear and unbiased, the GEE estimator achieves full efficiency across a wide class of potential dispersion and correlation matrices for the compositional response variables. As for any other GEE estimator, the estimator used in the generalized Wedderburn method is also asymptotically unbiased and consistent, provided that the marginal mean model specification is correct. The theoretical results derived in this thesis are substantiated by simulation experiments, and properties of the new model are also studied empirically on some classic datasets from the literature.
Subjects/Keywords: QA Mathematics
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APA ·
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Export
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APA (6th Edition):
Sammut, F. (2016). Using generalized linear models to model compositional response data. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/89876/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720443
Chicago Manual of Style (16th Edition):
Sammut, Fiona. “Using generalized linear models to model compositional response data.” 2016. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/89876/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720443.
MLA Handbook (7th Edition):
Sammut, Fiona. “Using generalized linear models to model compositional response data.” 2016. Web. 23 Oct 2017.
Vancouver:
Sammut F. Using generalized linear models to model compositional response data. [Internet] [Doctoral dissertation]. University of Warwick; 2016. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/89876/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720443.
Council of Science Editors:
Sammut F. Using generalized linear models to model compositional response data. [Doctoral Dissertation]. University of Warwick; 2016. Available from: http://wrap.warwick.ac.uk/89876/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720443
University of Warwick
21.
Vincent, Ian.
Lines on intersections of three quadrics.
Degree: PhD, 2016, University of Warwick
URL: http://wrap.warwick.ac.uk/90063/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720447
► In this document we formulate and discuss conjecture 1.2.1, giving an upper bound for the number of lines on K3 surfaces occurring as complete intersections…
(more)
▼ In this document we formulate and discuss conjecture 1.2.1, giving an upper bound for the number of lines on K3 surfaces occurring as complete intersections of three quadrics in P5. In the case that these quadrics contain in their span a quadric of rank 4, we construct a pair of elliptic fibrations, each of which realises the lines on the surface as either sections or line components within the singular fibres, and the general fibre is realised as an intersection of two quadrics in P3. The possibilities for singular fibres are limited by the Euler number of the surface, while the rank of the group of sections is bounded by the rank of its Picard group. In the cases where this rank is low, these bounds are enough to prove the stated conjecture in the torsion-free case by utilising the height-pairing. In the remaining cases, if a surface has more lines than the stated conjecture, we discuss how these techniques can be used to construct necessary conditions on the configurations of the lines on the surface, along with an example of how this could work in practice.
Subjects/Keywords: QA Mathematics
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Export
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APA (6th Edition):
Vincent, I. (2016). Lines on intersections of three quadrics. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/90063/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720447
Chicago Manual of Style (16th Edition):
Vincent, Ian. “Lines on intersections of three quadrics.” 2016. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/90063/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720447.
MLA Handbook (7th Edition):
Vincent, Ian. “Lines on intersections of three quadrics.” 2016. Web. 23 Oct 2017.
Vancouver:
Vincent I. Lines on intersections of three quadrics. [Internet] [Doctoral dissertation]. University of Warwick; 2016. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/90063/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720447.
Council of Science Editors:
Vincent I. Lines on intersections of three quadrics. [Doctoral Dissertation]. University of Warwick; 2016. Available from: http://wrap.warwick.ac.uk/90063/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720447
University of Warwick
22.
Collazo, Rodrigo A.
The dynamic chain event graph.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/91075/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720530
► The Chain Event Graph (CEG) is a type of tree-based graphical model that accommodates all discrete Bayesian Networks as a particular subclass. It has already…
(more)
▼ The Chain Event Graph (CEG) is a type of tree-based graphical model that accommodates all discrete Bayesian Networks as a particular subclass. It has already been successfully used to capture context-specific conditional independence structures of highly asymmetric processes in a way easily appreciated by domain experts. Being built from a tree, a CEG has a huge number of free parameters that makes the class extremely expressive but also very large. Exploring the enormous CEG model space then makes it necessary to design bespoke algorithms for this purpose. All Bayesian algorithms for CEG model selection in the literature are based on the Dirichlet characterisation of a family of CEGs spanned by a single event tree. Here I generalise this framework for a CEG model space spanned by a collection of different event trees. A new concept called hyper-stage is also introduced and provides us with a framework to design more efficient algorithms. These improvements are nevertheless insufficient to scale up the model search for more challenging applications. In other contexts, recent analyses of Bayes Factor model selection using conjugate priors have suggested that the use of such prior settings tends to choose models that are not sufficiently parsimonious. To sidestep this phenomenon, non-local priors (NLPs) have been successfully developed. These priors enable the fast identification of the simpler model when it really does drive the data generation process. In this thesis, I define three new families of NLPs designed to be applied specifically to discrete processes defined through trees. In doing this, I develop a framework for a CEG model search which appears to be both robust and computationally efficient. Finally, I define a Dynamic Chain Event Graph (DCEG). I develop object-recursive methods to fully analyse a particularly useful and feasibly implementable new subclass of these models called the N Time-Slice DCEG (NT-DCEG). By exploiting its close links with the Dynamic Bayesian Network I show how the NT-DCEG can be used to depict various structural and Granger causal hypotheses about a studied process. I also show how to construct from the topology of this graph intrinsic random variables which exhibit context-specific independences that can then be checked by domain experts. Throughout the thesis my methods are illustrated using examples of multivariate processes describing inmate radicalisation in a prison, and survey data concerning childhood hospitalisation and booking a tourist train.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Collazo, R. A. (2017). The dynamic chain event graph. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/91075/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720530
Chicago Manual of Style (16th Edition):
Collazo, Rodrigo A. “The dynamic chain event graph.” 2017. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/91075/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720530.
MLA Handbook (7th Edition):
Collazo, Rodrigo A. “The dynamic chain event graph.” 2017. Web. 23 Oct 2017.
Vancouver:
Collazo RA. The dynamic chain event graph. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/91075/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720530.
Council of Science Editors:
Collazo RA. The dynamic chain event graph. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/91075/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720530
University of Warwick
23.
Hobbs, Graham.
Particles and biomembranes : a variational PDE approach.
Degree: PhD, 2016, University of Warwick
URL: http://wrap.warwick.ac.uk/90319/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720469
► We examine mathematical models for small deformations of membranes. First we review physically well-established models, posed in the Monge gauge, from a mathematical perspective. We…
(more)
▼ We examine mathematical models for small deformations of membranes. First we review physically well-established models, posed in the Monge gauge, from a mathematical perspective. We produce a variational framework in which well posedness can be studied and finite element methods applied. The methods are used to investigate the effects of point forces, point displacement constraints and point curvature constraints. Such models are suitable for the study of deformations induced by filaments contained in the cell cytoskeleton and by embedded protein inclusions. In particular we study the membrane mediated interactions between filaments and also between inclusions. We then introduce a new linearised model which describes small deformations of closed surfaces that are minimisers of Helfrich-type energies. The deformed surface is described as a graph over the Helfrich minimising undeformed surface. This is the natural generalisation of the Monge gauge to initially curved surfaces. We focus on a Willmore energy which gives rise to spheres and a family of tori as undeformed surfaces and also introduce surface tension on a sphere. Again we study deformations induced by filaments. A variational formulation is produced which is similar to the Monge gauge case and we formulate a numerical method to study membrane mediated interactions. Finally we introduce an abstract splitting method which allows a high order PDE to be solved by an equivalent system of lower order equations. We give conditions which ensure well posedness of the system and produce a finite element method whose solution converges to the solution of the full system. The theory is applied to show convergence for the numerical methods used for the surface deformations model. We provide examples which show the theoretical error estimates are achieved.
Subjects/Keywords: QA Mathematics
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APA ·
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MLA ·
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Export
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Manager
APA (6th Edition):
Hobbs, G. (2016). Particles and biomembranes : a variational PDE approach. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/90319/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720469
Chicago Manual of Style (16th Edition):
Hobbs, Graham. “Particles and biomembranes : a variational PDE approach.” 2016. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/90319/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720469.
MLA Handbook (7th Edition):
Hobbs, Graham. “Particles and biomembranes : a variational PDE approach.” 2016. Web. 23 Oct 2017.
Vancouver:
Hobbs G. Particles and biomembranes : a variational PDE approach. [Internet] [Doctoral dissertation]. University of Warwick; 2016. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/90319/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720469.
Council of Science Editors:
Hobbs G. Particles and biomembranes : a variational PDE approach. [Doctoral Dissertation]. University of Warwick; 2016. Available from: http://wrap.warwick.ac.uk/90319/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720469
University of Warwick
24.
Coles, Ben.
Conjugacy in braid groups and the LKB representation, and Bessis-Garside groups of rank 3.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/90207/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720511
► In the first part of this thesis, we give a survey of the conjugacy problem in the braid group, describing the solution provided by Garside…
(more)
▼ In the first part of this thesis, we give a survey of the conjugacy problem in the braid group, describing the solution provided by Garside theory, and outlining the progress that has been made towards a polynomial time solution in recent years using refinements of Garside's solution, and the Thurston-Nielsen classification of braids, which reduces the problem to the case of pseudo-Anosov braids. Using the faithful Lawrence-Krammer-Bigelow representation of the braid groups, we consider how the eigenspaces of pseudo-Anosov braids can under certain conditions yield invariants of their conjugacy class and thus lead us towards a polynomial time solution of the conjugacy problem. In the second part we introduce Bessis-Garside groups, a generalisation of the methods used by Bessis in his papers on dual braid monoids. We consider the groups given by taking the quotient of the free group by the orbits of its generators under the action of some subgroup of the braid group, and find that in many cases this construction can give us a group with a Garside structure. By means of introduction we review the simple rank 2 case, and summarise examples of such groups already known to admit Garside structures, in particular due to the work of Digne. We then go on to give all those of such groups which can be found as quotients of affine and spherical Artin groups of rank 3. We show that all such groups may be given a cycle presentation, or equivalently may be given as labelled-oriented-graph presented groups, and give conditions on such presentations that are equivalent to the group admitting a `dual' Garside structure. Restricting by the cycle lengths occurring in such presentations we give all Bessis-Garside groups of rank 3 which have all cycles length at most 4, and discuss the case of Bessis-Garside groups with uniform cycle length.
Subjects/Keywords: QA Mathematics
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APA ·
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MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Coles, B. (2017). Conjugacy in braid groups and the LKB representation, and Bessis-Garside groups of rank 3. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/90207/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720511
Chicago Manual of Style (16th Edition):
Coles, Ben. “Conjugacy in braid groups and the LKB representation, and Bessis-Garside groups of rank 3.” 2017. Doctoral Dissertation, University of Warwick. Accessed October 23, 2017.
http://wrap.warwick.ac.uk/90207/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720511.
MLA Handbook (7th Edition):
Coles, Ben. “Conjugacy in braid groups and the LKB representation, and Bessis-Garside groups of rank 3.” 2017. Web. 23 Oct 2017.
Vancouver:
Coles B. Conjugacy in braid groups and the LKB representation, and Bessis-Garside groups of rank 3. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2017 Oct 23].
Available from: http://wrap.warwick.ac.uk/90207/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720511.
Council of Science Editors:
Coles B. Conjugacy in braid groups and the LKB representation, and Bessis-Garside groups of rank 3. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/90207/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720511
University of Birmingham
25.
Grazian, Valentina.
Fusion systems on ρ-groups of sectional rank 3.
Degree: PhD, 2017, University of Birmingham
URL: http://etheses.bham.ac.uk/7670/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720756
► In this thesis we study saturated fusion systems on ρ-groups having sectional rank 3, for ρ odd. We obtain a complete classification of simple fusion…
(more)
▼ In this thesis we study saturated fusion systems on ρ-groups having sectional rank 3, for ρ odd. We obtain a complete classification of simple fusion systems on p-groups having sectional rank 3 for ρ ≥ 5, exhibiting a new simple exotic fusion system on a 7-group of order 75. We introduce the notion of pearls, defined as essential subgroups isomorphic to the groups C_ρ X_ρ and ρ₊¹⁺² (for odd), and we illustrate some properties of fusion systems involving pearls. As for ρ = 3, we determine the isomorphism type of a certain section of the 3-groups considered.
Subjects/Keywords: QA Mathematics
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APA ·
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MLA ·
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Export
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APA (6th Edition):
Grazian, V. (2017). Fusion systems on ρ-groups of sectional rank 3. (Doctoral Dissertation). University of Birmingham. Retrieved from http://etheses.bham.ac.uk/7670/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720756
Chicago Manual of Style (16th Edition):
Grazian, Valentina. “Fusion systems on ρ-groups of sectional rank 3.” 2017. Doctoral Dissertation, University of Birmingham. Accessed October 23, 2017.
http://etheses.bham.ac.uk/7670/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720756.
MLA Handbook (7th Edition):
Grazian, Valentina. “Fusion systems on ρ-groups of sectional rank 3.” 2017. Web. 23 Oct 2017.
Vancouver:
Grazian V. Fusion systems on ρ-groups of sectional rank 3. [Internet] [Doctoral dissertation]. University of Birmingham; 2017. [cited 2017 Oct 23].
Available from: http://etheses.bham.ac.uk/7670/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720756.
Council of Science Editors:
Grazian V. Fusion systems on ρ-groups of sectional rank 3. [Doctoral Dissertation]. University of Birmingham; 2017. Available from: http://etheses.bham.ac.uk/7670/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720756
University of Birmingham
26.
Beltran Portalés, David.
Geometric control of oscillatory integrals.
Degree: PhD, 2017, University of Birmingham
URL: http://etheses.bham.ac.uk/7566/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715700
► The aim of this thesis is to provide a geometric control of certain oscillatory integral operators. In particular, if (T) is an oscillatory Fourier multiplier,…
(more)
▼ The aim of this thesis is to provide a geometric control of certain oscillatory integral operators. In particular, if (T) is an oscillatory Fourier multiplier, a pseudodifferential operator associated to a symbol (α) (∈) (S) (m) ({p,o}) or a Carleson-like operator, we obtain a weighted (L)(2) inequality of the type (∈t) |(T)(f)|(2)w ( ≤ ) C (∈t) |(f)|(2)(M)(T)w Here (C) is a constant independent of the weight function w, and the operator (M)(T), which depends on the corresponding T, has an explicit geometric character. In the case of oscillatory Fourier multipliers and of Carleson-like operators we also determine auxiliary geometric operators (g)1 and (g)2 and establish a (pointwise) estimate of the type (g)(1)((T)(f))(x) ( ≤ ) C (g)(2)(f)(x): Finally, we include a careful study of a method developed by Bourgain and Guth in Fourier restriction theory, that allows making progress on the Fourier restriction conjecture from their conjectured multilinear counterparts. Our conjectured progress via multilinear estimates has been recently obtained by Guth.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Beltran Portalés, D. (2017). Geometric control of oscillatory integrals. (Doctoral Dissertation). University of Birmingham. Retrieved from http://etheses.bham.ac.uk/7566/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715700
Chicago Manual of Style (16th Edition):
Beltran Portalés, David. “Geometric control of oscillatory integrals.” 2017. Doctoral Dissertation, University of Birmingham. Accessed October 23, 2017.
http://etheses.bham.ac.uk/7566/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715700.
MLA Handbook (7th Edition):
Beltran Portalés, David. “Geometric control of oscillatory integrals.” 2017. Web. 23 Oct 2017.
Vancouver:
Beltran Portalés D. Geometric control of oscillatory integrals. [Internet] [Doctoral dissertation]. University of Birmingham; 2017. [cited 2017 Oct 23].
Available from: http://etheses.bham.ac.uk/7566/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715700.
Council of Science Editors:
Beltran Portalés D. Geometric control of oscillatory integrals. [Doctoral Dissertation]. University of Birmingham; 2017. Available from: http://etheses.bham.ac.uk/7566/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715700
27.
Wang, Wenfei.
Aspects of wave propagation in anisotropic elastic half-spaces and plates.
Degree: PhD, 2013, Keele University
URL: http://eprints.keele.ac.uk/3737/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718473
► The propagation of waves along elastic half-spaces and plates has long been an active research area with lots of applications in seismology andmodern industries. Much…
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▼ The propagation of waves along elastic half-spaces and plates has long been an active research area with lots of applications in seismology andmodern industries. Much attention has been paid to the study of wave propagation in a linear isotropic solid with traction-free or fixed boundary conditions. However, much more investigation is deserved for anisotropic solids under other type of boundary conditions, or even a solid with a hump on its surface. The purpose of the thesis is to investigate the influence of the elastic property and profile of propagation media and boundary conditions on wave speeds, and predict the wave speed in various situations. Chapter 1 is devoted to introducing the governing equations and several specific materials used as examples in subsequent analysis. Chapter 2 is concerned with the propagation of free surface waves on an elastic half-space that has a localized geometric inhomogeneity perpendicular to the direction of wave propagation (such waves are known as topography-guided surface waves). We use the Stroh formalism to examine how such hump modifies the surface wave speed slightly on an anisotropic elastic half-space. In Chapter 3, an asymptotic model is constructed to predict the speed of waves propagating along a thin elastic plate with elastically restrained boundary conditions (ERBC). The Stroh formalism is again applied to deal with general anisotropy, which can be specified later to analyze the case of linear isotropy and the transverse isotropy. Chapter 4 deals again with the case of a thin plate with ERBC as in the previous chapter, but the effects of pre-stress and the condition of incompressibility are also considered.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Wang, W. (2013). Aspects of wave propagation in anisotropic elastic half-spaces and plates. (Doctoral Dissertation). Keele University. Retrieved from http://eprints.keele.ac.uk/3737/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718473
Chicago Manual of Style (16th Edition):
Wang, Wenfei. “Aspects of wave propagation in anisotropic elastic half-spaces and plates.” 2013. Doctoral Dissertation, Keele University. Accessed October 23, 2017.
http://eprints.keele.ac.uk/3737/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718473.
MLA Handbook (7th Edition):
Wang, Wenfei. “Aspects of wave propagation in anisotropic elastic half-spaces and plates.” 2013. Web. 23 Oct 2017.
Vancouver:
Wang W. Aspects of wave propagation in anisotropic elastic half-spaces and plates. [Internet] [Doctoral dissertation]. Keele University; 2013. [cited 2017 Oct 23].
Available from: http://eprints.keele.ac.uk/3737/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718473.
Council of Science Editors:
Wang W. Aspects of wave propagation in anisotropic elastic half-spaces and plates. [Doctoral Dissertation]. Keele University; 2013. Available from: http://eprints.keele.ac.uk/3737/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718473
University of Glasgow
28.
Li, Beibei.
Mathematical modelling of aortic dissection.
Degree: 2013, University of Glasgow
URL: http://theses.gla.ac.uk/3968/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566454
► An aortic dissection is a tear of the intima of the aortic wall that spreads into the media or between the media and adventitia. In…
(more)
▼ An aortic dissection is a tear of the intima of the aortic wall that spreads into the media or between the media and adventitia. In addition to the original lumen for blood flow, the dissection creates a new flow channel, the `false' lumen that may cause the artery to narrow or even close over entirely. Aortic dissection is a medical emergency and can quickly lead to death. The mechanical property of the aorta has been described by the strain energy function given by Holzapfel et al. [2000]. The aorta is idealized as an elastic axisymmetric thickwalled tube with 3 layers. We focus on the dissection in media, which is considered as a composite reinforced by two families of fibres. We assume the dissection in the media is axisymmetric. The mathematical model for the dissection is presented. The 2D plane crack problem in linear elastic infinity plane and 2D strip, the axisymmetric crack problem in linear elastic compressible and incompressible tube, the axisymmetric crack problem in an incompressible axisymmetric aorta are applied to obtain solutions to three different problems. And the fluid flow inside the crack has been studied. The 2D plane crack problem in linear elastic infinity plane has been solved analytically. The 2D plane crack problem in linear elastic compressible and incompressible strip is modelled respectively and solved numerically. The models for axisymmetric crack problem in linear elastic compressible and incompressible tube are presented respectively. The numerical solutions for the crack problems are expressed, and the results are analyzed. The mathematical model of the incompressible aorta axisymmetric dissection is given, and the solutions are found numerically. The results change along with the different parameters in the strain energy function, which are analyzed and compared. The fluid flow inside the tear is assumed very thin which is expressed as the lubrication theory. We use the implicit method to model the Stokes equation numerically, and test the crack opening change along with time.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Li, B. (2013). Mathematical modelling of aortic dissection. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/3968/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566454
Chicago Manual of Style (16th Edition):
Li, Beibei. “Mathematical modelling of aortic dissection.” 2013. Doctoral Dissertation, University of Glasgow. Accessed October 23, 2017.
http://theses.gla.ac.uk/3968/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566454.
MLA Handbook (7th Edition):
Li, Beibei. “Mathematical modelling of aortic dissection.” 2013. Web. 23 Oct 2017.
Vancouver:
Li B. Mathematical modelling of aortic dissection. [Internet] [Doctoral dissertation]. University of Glasgow; 2013. [cited 2017 Oct 23].
Available from: http://theses.gla.ac.uk/3968/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566454.
Council of Science Editors:
Li B. Mathematical modelling of aortic dissection. [Doctoral Dissertation]. University of Glasgow; 2013. Available from: http://theses.gla.ac.uk/3968/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566454
University of Glasgow
29.
Almahmud, Reem Abdullah J.
Wavelengths in bioconvection patterns.
Degree: PhD, 2016, University of Glasgow
URL: http://theses.gla.ac.uk/7834/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700414
► Unicellular bottom-heavy swimming microorganisms are usually denser than the fluid in which they swim. In shallow suspensions, the bottom heaviness results in a gravitational torque…
(more)
▼ Unicellular bottom-heavy swimming microorganisms are usually denser than the fluid in which they swim. In shallow suspensions, the bottom heaviness results in a gravitational torque that orients the cells to swim vertically upwards in the absence of fluid flow. Swimming cells thus accumulate at the upper surface to form a concentrated layer of cells. When the cell concentration is high enough, the layer overturns to form bioconvection patterns. Thin concentrated plumes of cells descend rapidly and cells return to the upper surface in wide, slowly moving upwelling plumes. When there is fluid flow, a second viscous torque is exerted on the swimming cells. The balance between the local shear flow viscous and the gravitational torques determines the cells' swimming direction, (gyrotaxis). In this thesis, the wavelengths of bioconvection patterns are studied experimentally as well as theoretically as follow; First, in aquasystem it is rare to find one species lives individually and when they swim they can form complex patterns. Thus, a protocol for controlled experiments to mix two species of swimming algal cells of \emph{C. rienhardtii} and \emph{C. augustae} is systematically described and images of bioconvection patterns are captured. A method for analysing images using wavelets and extracting the local dominant wavelength in spatially varying patterns is developed. The variation of the patterns as a function of the total concentration and the relative concentration between two species is analysed. Second, the linear stability theory of bioconvection for a suspension of two mixed species is studied. The dispersion relationship is computed using Fourier modes in order to calculate the neutral curves as a function of wavenumbers k and m. The neutral curves are plotted to compare the instability onset of the suspension of the two mixed species with the instability onset of each species individually. This study could help us to understand which species contributes the most in the process of pattern formation. Finally, predicting the most unstable wavelength was studied previously around a steady state equilibrium situation. Since assuming steady state equilibrium contradicts with reality, the pattern formation in a layer of finite depth of an evolving basic state is studied using the nonnormal modes approach. The nonnormal modes procedure identifies the optimal initial perturbation that can be obtained for a given time t as well as a given set of parameters and wavenumber k. Then, we measure the size of the optimal perturbation as it grows with time considering a range of wavenumbers for the same set of parameters to be able to extract the most unstable wavelength.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Almahmud, R. A. J. (2016). Wavelengths in bioconvection patterns. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/7834/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700414
Chicago Manual of Style (16th Edition):
Almahmud, Reem Abdullah J. “Wavelengths in bioconvection patterns.” 2016. Doctoral Dissertation, University of Glasgow. Accessed October 23, 2017.
http://theses.gla.ac.uk/7834/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700414.
MLA Handbook (7th Edition):
Almahmud, Reem Abdullah J. “Wavelengths in bioconvection patterns.” 2016. Web. 23 Oct 2017.
Vancouver:
Almahmud RAJ. Wavelengths in bioconvection patterns. [Internet] [Doctoral dissertation]. University of Glasgow; 2016. [cited 2017 Oct 23].
Available from: http://theses.gla.ac.uk/7834/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700414.
Council of Science Editors:
Almahmud RAJ. Wavelengths in bioconvection patterns. [Doctoral Dissertation]. University of Glasgow; 2016. Available from: http://theses.gla.ac.uk/7834/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700414
University of Glasgow
30.
Castillejos Lopez, Jorge.
Decomposable approximations and coloured isomorphisms for C*-algebras.
Degree: PhD, 2016, University of Glasgow
URL: http://theses.gla.ac.uk/7650/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695170
► In this thesis we introduce nuclear dimension and compare it with a stronger form of the completely positive approximation property. We show that the approximations…
(more)
▼ In this thesis we introduce nuclear dimension and compare it with a stronger form of the completely positive approximation property. We show that the approximations forming this stronger characterisation of the completely positive approximation property witness finite nuclear dimension if and only if the underlying C*-algebra is approximately finite dimensional. We also extend this result to nuclear dimension at most omega. We review interactions between separably acting injective von Neumann algebras and separable nuclear C*-algebras. In particular, we discuss aspects of Connes' work and how some of his strategies have been used by C^*-algebraist to estimate the nuclear dimension of certain classes of C*-algebras. We introduce a notion of coloured isomorphisms between separable unital C*-algebras. Under these coloured isomorphisms ideal lattices, trace spaces, commutativity, nuclearity, finite nuclear dimension and weakly pure infiniteness are preserved. We show that these coloured isomorphisms induce isomorphisms on the classes of finite dimensional and commutative C*-algebras. We prove that any pair of Kirchberg algebras are 2-coloured isomorphic and any pair of separable, simple, unital, finite, nuclear and Z-stable C*-algebras with unique trace which satisfy the UCT are also 2-coloured isomorphic.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
Castillejos Lopez, J. (2016). Decomposable approximations and coloured isomorphisms for C*-algebras. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/7650/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695170
Chicago Manual of Style (16th Edition):
Castillejos Lopez, Jorge. “Decomposable approximations and coloured isomorphisms for C*-algebras.” 2016. Doctoral Dissertation, University of Glasgow. Accessed October 23, 2017.
http://theses.gla.ac.uk/7650/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695170.
MLA Handbook (7th Edition):
Castillejos Lopez, Jorge. “Decomposable approximations and coloured isomorphisms for C*-algebras.” 2016. Web. 23 Oct 2017.
Vancouver:
Castillejos Lopez J. Decomposable approximations and coloured isomorphisms for C*-algebras. [Internet] [Doctoral dissertation]. University of Glasgow; 2016. [cited 2017 Oct 23].
Available from: http://theses.gla.ac.uk/7650/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695170.
Council of Science Editors:
Castillejos Lopez J. Decomposable approximations and coloured isomorphisms for C*-algebras. [Doctoral Dissertation]. University of Glasgow; 2016. Available from: http://theses.gla.ac.uk/7650/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695170
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