You searched for subject:(QA Mathematics).
Showing records 1 – 30 of
1947 total matches.
◁ [1] [2] [3] [4] [5] … [65] ▶
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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
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 2018 Jul 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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Ali A. Stochastic pattern formation in growth models with spatial competition. [Internet] [Doctoral dissertation]. University of Warwick; 2012. [cited 2018 Jul 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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Lloyd T. Advancing integrability for strings in AdS3/CFT2. [Internet] [Doctoral dissertation]. City University London; 2016. [cited 2018 Jul 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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
King O. The representation theory of diagram algebras. [Internet] [Doctoral dissertation]. City University London; 2014. [cited 2018 Jul 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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Malekpoor S. Optimization methods for deadbeat control design : a state space approach. [Internet] [Doctoral dissertation]. City University London; 2016. [cited 2018 Jul 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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Wang J. A hybrid model for large scale simulation of unsteady nonlinear waves. [Internet] [Doctoral dissertation]. City University London; 2016. [cited 2018 Jul 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
7.
Chieng, Hock Hung.
A genetic simplified swarm algorithm for optimizing n- cities open loop travelling salesman problem.
Degree: Faculty of Computer Science and Information Technology, 2016, Universiti Tun Hussein Onn Malaysia
URL: http://eprints.uthm.edu.my/8870/
► Open Loop Travelling Salesman Problem (OTSP) is one of the extension of Travelling Salesman Problem (TSP) that finding a shortest tour of a number of…
(more)
▼ Open Loop Travelling Salesman Problem (OTSP) is one of the extension of
Travelling Salesman Problem (TSP) that finding a shortest tour of a number of cities
by visiting each city exactly once and do not returning to the starting city. In the past,
TSP and OTSP has been applied in various vehicle routing systems to optimize the
route distance. However, in real-life scenario such as transportation problem does not
seem similar as pictured in OTSP whereby do not all cities are required to be visited
but simply restrain to several number of n cities. Therefore, a new problem called n-
Cities Open Loop Travelling Salesman Problem (nOTSP) is proposed. In the past,
Genetic Algorithm (GA) is a popular algorithm that used to solve TSPs. However,
GA often suffers from premature convergence due to the difficulty in preventing the
loss of genetic diversity in the population. Therefore, Genetic Simplified Swarm
Algorithm (GSSA) is proposed in this study to overcome the drawback of GA.
GSSA is an improved GA based algorithm with Simplified Swarm Optimization
(SSO) algorithm’s characteristic named Solution Update Mechanism (SUM). The
SUM is modified by embedding three GA mutation operators. Then, GSSA is used
to optimize nOTSP in terms of finding the shortest tour. Later, the performance of
GSSA is compared with GA without crossover operator (GA-XX) and GA with onepoint
crossover operator (GA-1X). Performance of the proposed algorithm is
measured based on the shortest distance and average shortest distance found by the
algorithm. Meanwhile, an investigation on influence of population size towards
algorithm was also studied. The experiment results show that GSSA can discover
shorter tour than GA-XX and GA-1X. Nevertheless, the study also found that most
of the good solutions are discovered in the larger population sizes from 3000 to 5000.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Chieng, H. H. (2016). A genetic simplified swarm algorithm for optimizing n- cities open loop travelling salesman problem. (Masters Thesis). Universiti Tun Hussein Onn Malaysia. Retrieved from http://eprints.uthm.edu.my/8870/
Chicago Manual of Style (16th Edition):
Chieng, Hock Hung. “A genetic simplified swarm algorithm for optimizing n- cities open loop travelling salesman problem.” 2016. Masters Thesis, Universiti Tun Hussein Onn Malaysia. Accessed July 23, 2018.
http://eprints.uthm.edu.my/8870/.
MLA Handbook (7th Edition):
Chieng, Hock Hung. “A genetic simplified swarm algorithm for optimizing n- cities open loop travelling salesman problem.” 2016. Web. 23 Jul 2018.
Vancouver:
Chieng HH. A genetic simplified swarm algorithm for optimizing n- cities open loop travelling salesman problem. [Internet] [Masters thesis]. Universiti Tun Hussein Onn Malaysia; 2016. [cited 2018 Jul 23].
Available from: http://eprints.uthm.edu.my/8870/.
Council of Science Editors:
Chieng HH. A genetic simplified swarm algorithm for optimizing n- cities open loop travelling salesman problem. [Masters Thesis]. Universiti Tun Hussein Onn Malaysia; 2016. Available from: http://eprints.uthm.edu.my/8870/
8.
Anwar Lashari, Saima.
Mammogram images classification based on fuzzy soft set.
Degree: PhD, Faculty of Computer Science and Information Technology, 2016, Universiti Tun Hussein Onn Malaysia
URL: http://eprints.uthm.edu.my/8882/
► Early detection of the breast cancer can decrease mortality rates. Screening mammography is considered the most reliable method in early detection of breast cancer. Due…
(more)
▼ Early detection of the breast cancer can decrease mortality rates. Screening
mammography is considered the most reliable method in early detection of breast
cancer. Due to the high volume of mammograms to be read by a physician, the
accuracy rate tends to decrease. Thus, automatic digital mammograms reading
becomes highly enviable, it is premised that the computer aided diagnosis systems
are required to assist physicians/radiologists to achieve high efficiency and
effectiveness. Meanwhile, recent advances in the field of image processing have
revealed that level of noise highly affect the mammogram images quality and
classification performance of the classifiers. Therefore, this study investigates the
functionality of wavelet de-noising filters for improving images quality. The dataset
taken from Mammographic Image Analysis Society (MIAS). The best PSNR and
MSE values 46.36423dB (hard thresholding) and 1.827967 achieved with Daub3
filter. Whilst, several medical imaging modalities and applications based on data
mining techniques have been proposed and developed. However, fuzzy soft set
theory has been merely experimented for medical images even though the choice of
convenient parameterization makes fuzzy soft set practicable for decision making
applications. Therefore, the viability of fuzzy soft set for classification of
mammograms images has been scrutinized. Experimental results show better
classification performance in the presence/absence of de-noise filter in mammogram
images where the highest classification rate occurs with Daub3 (Level 1) with
accuracy 75.64% (hard threshold), precision 46.11%, recall 84.67%, F-Macro
75.64%, F-Micro 60% and performance of FussCyier without de-noise filter
classification accuracy 66.49%, precision 80.83%, recall 50% and F-Micro 68.18%.
Thus, the results show that proposed approach FussCyier gives high level of
accuracy and reduce the complexity of the classification phase, thus provides an
alternative technique to categorize mammogram images.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Anwar Lashari, S. (2016). Mammogram images classification based on fuzzy soft set. (Doctoral Dissertation). Universiti Tun Hussein Onn Malaysia. Retrieved from http://eprints.uthm.edu.my/8882/
Chicago Manual of Style (16th Edition):
Anwar Lashari, Saima. “Mammogram images classification based on fuzzy soft set.” 2016. Doctoral Dissertation, Universiti Tun Hussein Onn Malaysia. Accessed July 23, 2018.
http://eprints.uthm.edu.my/8882/.
MLA Handbook (7th Edition):
Anwar Lashari, Saima. “Mammogram images classification based on fuzzy soft set.” 2016. Web. 23 Jul 2018.
Vancouver:
Anwar Lashari S. Mammogram images classification based on fuzzy soft set. [Internet] [Doctoral dissertation]. Universiti Tun Hussein Onn Malaysia; 2016. [cited 2018 Jul 23].
Available from: http://eprints.uthm.edu.my/8882/.
Council of Science Editors:
Anwar Lashari S. Mammogram images classification based on fuzzy soft set. [Doctoral Dissertation]. Universiti Tun Hussein Onn Malaysia; 2016. Available from: http://eprints.uthm.edu.my/8882/
9.
Hill, Sally.
Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions.
Degree: PhD, 2018, University of Cardiff
URL: http://orca.cf.ac.uk/111467/
► We say that two sets A and B, each of cardinality m, form an m+m \emph{sum-and-distance system} {A,B} if the sum-and-distance set A^*B comprised of…
(more)
▼ We say that two sets A and B, each of cardinality m, form an m+m \emph{sum-and-distance system} {A,B} if the sum-and-distance set A^*B comprised of all the absolute values of the sums and distances ai± bj contains either the consecutive odd integers {1,3,5,… 4m2-1} or with the inclusion of the set elements themselves, the consecutive integers {1,2,3,…,2m(m+1)} (an inclusive sum-and-distance system). Sum-and-distance systems can be thought of as a discrete analogue of the union of a Minkowski sum system with a Minkowski difference system. We show that they occur naturally within a traditional reversible square matrix, where conjugation with a specific orthogonal symmetric involution, always reveals a sum-and-distance system within the block structure of the conjugated matrix. Moreover, we show that the block representation is an algebra isomorphism.
Building upon results of Ollerenshaw, and Br\'ee, for a fixed dimension n, we establish a bijection between the set of sum-and-distance systems and the set of traditional principal reversible square matrices of size n × n. Using the jth non-trivial divisor function cj (n), which counts the total number of proper ordered factorisations of the integer n= p1a1… ptat into j parts, we prove that the total number of n+n principal reversible square matrices, and so sum-and-distance systems, Nn, is given by
[
Nn = ∑j=1Ω(n) ≤ ft( cj(n)2 +cj+1(n)cj(n) ))=∑j=1Ω(n) cj(0)(n) cj(1)(n).
]
[=∑j=1Ω(n) ≤ ft(∑ji=1(-1)j-i{j \choose i} \prodk=1t {ak +i -1 \choose i-1}) )
≤ ft ( ∑ji=0(-1)j-i{j \choose i} \prodk=1t {ak +i \choose i})),
]
where Ω(n)=a1 + a2 + … + at is the total number of prime factors (including repeats) of n.
Further relations between the divisor functions and their Dirichlet series are deduced, as well as a construction algorithm for all sum-and-distance systems of either type.
Superalgebra structures relating to the matrix symmetry properties are identified, including those for the reversible and most-perfect square matrices of those considered by Ollerenshaw and Br\'ee. For certain symmetry types, links between the block representation constructed from a sum-and-distance system, and quadratic forms are also established.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Hill, S. (2018). Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions. (Doctoral Dissertation). University of Cardiff. Retrieved from http://orca.cf.ac.uk/111467/
Chicago Manual of Style (16th Edition):
Hill, Sally. “Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions.” 2018. Doctoral Dissertation, University of Cardiff. Accessed July 23, 2018.
http://orca.cf.ac.uk/111467/.
MLA Handbook (7th Edition):
Hill, Sally. “Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions.” 2018. Web. 23 Jul 2018.
Vancouver:
Hill S. Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions. [Internet] [Doctoral dissertation]. University of Cardiff; 2018. [cited 2018 Jul 23].
Available from: http://orca.cf.ac.uk/111467/.
Council of Science Editors:
Hill S. Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions. [Doctoral Dissertation]. University of Cardiff; 2018. Available from: http://orca.cf.ac.uk/111467/
10.
Arbaiy, Nureize.
Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications.
Degree: PhD, School of Information, Production and Systems, 2012, Waseda University
URL: http://eprints.uthm.edu.my/4652/
► In practice of various real-life applications, mathematical programming plays a pivotal role in finding the solution of their optimization problems. Conventionally, mathematical programming is set…
(more)
▼ In practice of various real-life applications, mathematical programming plays a pivotal role in
finding the solution of their optimization problems. Conventionally, mathematical programming
is set with numerical values although it is troublesome for decision makers to provide rigid
values in presence of uncertainties in decision making process. Building mathematical
programming model with crisp and precise values sometimes generates infeasible or improper
solution. Besides that, when the real-life application faces hybrid situation of simultaneous
fuzziness and randomness, or ambiguous and vague information, it makes the existing multicriteria
evaluation model incapable of handling such uncertainties. Satisficing based optimization
is used as underlying concept, that is to realize the reality of decision making process which
seeks for satisficing based solution rather that optimal solution. Hence, based on different multicriteria
evaluation scheme and requirement, the objective of this study is to propose three kinds
of mathematical programming model: (1) multi-attribute evaluation model, (2) satisficing based
multi-objective evaluation model, and (3) possibility based multi-objective evaluation model.
The initial model-setting of all is done by fuzzy random regression analysis, which alleviates the
difficulties to determine the model’s coefficients in fuzzy random circumstances. The algorithms
presented herein are accompanied with numerical experiments where data are taken from the
industry application of oil palm production. The analytical results of the proposed methods
reveal the improvement of conventional decision making approaches to appropriately handle
inherent uncertainties contained in the real-world situation. The implementation of the proposed
method shows the significant capabilities to solve real application problem.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Arbaiy, N. (2012). Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications. (Doctoral Dissertation). Waseda University. Retrieved from http://eprints.uthm.edu.my/4652/
Chicago Manual of Style (16th Edition):
Arbaiy, Nureize. “Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications.” 2012. Doctoral Dissertation, Waseda University. Accessed July 23, 2018.
http://eprints.uthm.edu.my/4652/.
MLA Handbook (7th Edition):
Arbaiy, Nureize. “Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications.” 2012. Web. 23 Jul 2018.
Vancouver:
Arbaiy N. Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications. [Internet] [Doctoral dissertation]. Waseda University; 2012. [cited 2018 Jul 23].
Available from: http://eprints.uthm.edu.my/4652/.
Council of Science Editors:
Arbaiy N. Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications. [Doctoral Dissertation]. Waseda University; 2012. Available from: http://eprints.uthm.edu.my/4652/
University of Glasgow
11.
Shu, Qingying.
Statistical modelling of the near-Earth magnetic field in space weather.
Degree: PhD, 2018, University of Glasgow
URL: http://theses.gla.ac.uk/8937/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.739274
► Space weather refers to electromagnetic disturbances in the near-Earth environment as a result of the Sun-Earth interaction. Severe space weather events such as magnetic storms…
(more)
▼ Space weather refers to electromagnetic disturbances in the near-Earth environment as a result of the Sun-Earth interaction. Severe space weather events such as magnetic storms can cause disruption to a wide range of technologies and infrastructure, including communications systems, electronic circuits and power grids. Because of its high potential impact, space weather has been included in the UK National Risk Register since 2011. Space weather monitoring and early magnetic storm detection can be used to mitigate risk in sensitive technological systems. The aim of this project is to investigate the electromagnetic disturbances in the near-Earth environment through developing statistical models that quantifies the variations and uncertainties in the near-Earth magnetic field. Data of the near-Earth magnetic field arise from in-situ satellite measurements and computer model outputs. The Cluster II mission (Escoubet et al., 2001a) has four satellites that provide in-situ measurements of the near-Earth magnetic field at time-varying locations along their trajectories. The computer model consists of an internal part that calculates the magnetic field sourced from Earth itself and an external part that estimates the magnetic field resulting from the Sun-Earth interaction. These magnetic fields, termed as the internal field and the external field, add up to the total magnetic field. Numerical estimates of the internal field and the external field are obtained respectively from the IGRF-11 model (Finlay et al., 2010) and the Tysganenko-96 (T96) model (Tsyganenko, 2013) given the times and the locations as inputs. The IGRF model outputs are invariant to space weather conditions whereas the T96 model outputs change with the input space weather parameters. The time-varying space weather parameters for T96 model include the solar wind ram pressure, the y and the z-components of the interplanetary magnetic field, and the disturbance storm time index. These parameters are the estimated time series of the solar wind conditions at the magnetopause, i.e. the boundary of the magnetosphere on the day-side, and the disturbance level at the Earth’s surface. Real-time values of the T96 model input parameters are available at hourly resolution from https://omniweb.gsfc.nasa.gov/. The overall aim of the thesis is to build spatio-temporal models that can be used to understand uncertainties and constraints leveraged from 3D mathematical models of space weather events. These spatio-temporal models can be then used to help understand the design parameters that need to be varied in building a precise and reliable sensor network. Chapter 1 provides an introduction to space weather in terms of the near-Earth magnetic field environment. Beginning with an overview of the near-Earth magnetic field environment, Chapter 2 describes the sources for generating in-situ satellite measurements and computer model outputs, namely the Cluster II mission, the IGRF model, and the T96 model. The process of sampling the magnetic field data from the different data…
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Shu, Q. (2018). Statistical modelling of the near-Earth magnetic field in space weather. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/8937/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.739274
Chicago Manual of Style (16th Edition):
Shu, Qingying. “Statistical modelling of the near-Earth magnetic field in space weather.” 2018. Doctoral Dissertation, University of Glasgow. Accessed July 23, 2018.
http://theses.gla.ac.uk/8937/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.739274.
MLA Handbook (7th Edition):
Shu, Qingying. “Statistical modelling of the near-Earth magnetic field in space weather.” 2018. Web. 23 Jul 2018.
Vancouver:
Shu Q. Statistical modelling of the near-Earth magnetic field in space weather. [Internet] [Doctoral dissertation]. University of Glasgow; 2018. [cited 2018 Jul 23].
Available from: http://theses.gla.ac.uk/8937/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.739274.
Council of Science Editors:
Shu Q. Statistical modelling of the near-Earth magnetic field in space weather. [Doctoral Dissertation]. University of Glasgow; 2018. Available from: http://theses.gla.ac.uk/8937/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.739274
Cardiff University
12.
Davies, Gareth.
Examination of approaches to calibration in survey sampling.
Degree: PhD, 2018, Cardiff University
URL: http://orca.cf.ac.uk/109727/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738413
► The analysis of sample surveys is one of the key areas in official statistics. An integral part of analysing sample data is choosing appropriate weights…
(more)
▼ The analysis of sample surveys is one of the key areas in official statistics. An integral part of analysing sample data is choosing appropriate weights for each sample member. These weights can informally be thought of as the number of population members each person in the sample represents. Calibration is a method that adjusts the weights assigned to sample members in order to satisfy (or approximately satisfy) some pre-determined constraints. These are typically based on Census data or other large surveys. The key idea is that estimates formed from the weighted sample should replicate the known values from other sources. This thesis begins with the mathematical formulation of the calibration problem as an optimization problem. Whilst the calibration problem has been defined in existing calibration literature, it has not been clearly formulated as a problem in optimization. New calibration functions are also presented, and an outline of their benefits compared to existing calibration functions given. Much of the calibration literature focuses on so-called hard calibration. This requires an exact matching between the weighted sample data and the pre-determined constraints. However, relaxing this condition can often lead to more “well-behaved” solutions. This is the idea behind soft calibration, which has received less attention in existing literature. In this thesis, soft calibration is formulated using an optimization framework, and also presented as a diagnostic tool for identifying problematic constraints. For many practitioners, the variance (and mean square error) of the estimates obtained is of particular interest. This is the motivation for a new approach to calibration that seeks to directly minimize the mean square error of the calibration estimator. This method is compared with existing calibration techniques, and future research directions for this approach are considered.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Davies, G. (2018). Examination of approaches to calibration in survey sampling. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/109727/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738413
Chicago Manual of Style (16th Edition):
Davies, Gareth. “Examination of approaches to calibration in survey sampling.” 2018. Doctoral Dissertation, Cardiff University. Accessed July 23, 2018.
http://orca.cf.ac.uk/109727/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738413.
MLA Handbook (7th Edition):
Davies, Gareth. “Examination of approaches to calibration in survey sampling.” 2018. Web. 23 Jul 2018.
Vancouver:
Davies G. Examination of approaches to calibration in survey sampling. [Internet] [Doctoral dissertation]. Cardiff University; 2018. [cited 2018 Jul 23].
Available from: http://orca.cf.ac.uk/109727/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738413.
Council of Science Editors:
Davies G. Examination of approaches to calibration in survey sampling. [Doctoral Dissertation]. Cardiff University; 2018. Available from: http://orca.cf.ac.uk/109727/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738413
University of Warwick
13.
Dunbar, Oliver.
A diffuse interface model of surfactants in multi-phase flow.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/99133/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737710
► We investigate a free boundary problem arising in fluid dynamics, by modelling multiple incompressible fluids over subdomains with different material quantities, and in the presence…
(more)
▼ We investigate a free boundary problem arising in fluid dynamics, by modelling multiple incompressible fluids over subdomains with different material quantities, and in the presence of surface tension reducing chemicals known as surfactants. We construct a free energy for this system, and we require it obey the second law of thermodynamics, leading to the formulation of an energy minimisation problem (the sharp problem). This problem is degenerate, so we regularise it by constructing a new energy of Ginzburg-Landau type, parametrised by a (small) constant ε > 0 and when ε → 0 the sharp problem is recovered in the sense of Γ-convergence. This multi-phase energy is formed from a multiwell potential and gradient term, and the minimisers are known as phase field variables. The phase field variables approximate characteristic functions of the subdomains, and the model is rewritten as functions of them. Beneficially, the energy analysis can be repeated as before to obtain a diffuse interface model. We construct and perform numerical analysis of a novel discretisation scheme for a Cahn-Hilliard Navier-Stokes system. Here we create a fractional-theta coupling scheme which is importantly proved to be of second order in time. The key property of this scheme is that it uses weighted operator splitting to separate the different nonlinearities that appear in a Cahn-Hilliard Navier-Stokes system. That is, the Cahn-Hilliard multiwell potential, the incompressibility condition and the convection. We discuss stability and the extension to surfactants. We implement the novel scheme in DUNE (Distributed Unified Numerics Environment), a finite element package and use simulation to run tests to validate the stability and consistency of the schemes, convergence of the diffuse interface model with respect to its parametrisation, and flexibility for the code development.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Dunbar, O. (2017). A diffuse interface model of surfactants in multi-phase flow. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/99133/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737710
Chicago Manual of Style (16th Edition):
Dunbar, Oliver. “A diffuse interface model of surfactants in multi-phase flow.” 2017. Doctoral Dissertation, University of Warwick. Accessed July 23, 2018.
http://wrap.warwick.ac.uk/99133/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737710.
MLA Handbook (7th Edition):
Dunbar, Oliver. “A diffuse interface model of surfactants in multi-phase flow.” 2017. Web. 23 Jul 2018.
Vancouver:
Dunbar O. A diffuse interface model of surfactants in multi-phase flow. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2018 Jul 23].
Available from: http://wrap.warwick.ac.uk/99133/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737710.
Council of Science Editors:
Dunbar O. A diffuse interface model of surfactants in multi-phase flow. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/99133/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737710
University of Warwick
14.
Tripoli, Paolo.
Chow hypersurfaces and realizability problems in tropical geometry.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/99839/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737741
► Tropical geometry is an area of mathematics between algebraic geometry, polyhedral geometry and combinatorics. The basic principle of tropical geometry is to associate to an…
(more)
▼ Tropical geometry is an area of mathematics between algebraic geometry, polyhedral geometry and combinatorics. The basic principle of tropical geometry is to associate to an algebraic variety X a polyhedral complex Trop(X) called the tropicalization of X. The tropicalization of X can be studied by means of polyhedral geometry and combinatorics and reflects many properties of the original variety X. Given a projective variety X . Pn of codimension k+1, the Chow hypersurface ZX is the hypersurface of the Grassmannian Gr(k; n) parametrizing k-dimensional linear subspaces of Pn that intersect X. In Chapter 3 we introduce and describe a tropical Chow hypersurface Trop(ZX). This object only depends on the tropical variety Trop(X) and we provide an explicit way to obtain Trop(ZX) from Trop(X). Finally we prove that, when X is a curve in P3 , Trop(X) can be reconstructed from Trop(ZX). In Chapter 4 we study the geometric properties of Chow hypersurfaces of space curves and other special varieties in the Grassmannian Gr(1; P3 ), such as the Hurwitz hypersurface and the bitangent congruence of a space surface. We give new proofs for the bidegrees of the secant, bitangent and in inflectional congruences, using geometric techniques such as duality, polar loci and projections. We also study the singularities of these congruences. In Chapter 5 we start with a family of projective curves and we study the geometric properties of the fibers by looking at their tropicalization. Given a tropical curve Ʃ and a family of algebraic curves X we produce an algorithm to describe the locus of fibbers of X whose tropicalization contains Ʃ.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tripoli, P. (2017). Chow hypersurfaces and realizability problems in tropical geometry. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/99839/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737741
Chicago Manual of Style (16th Edition):
Tripoli, Paolo. “Chow hypersurfaces and realizability problems in tropical geometry.” 2017. Doctoral Dissertation, University of Warwick. Accessed July 23, 2018.
http://wrap.warwick.ac.uk/99839/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737741.
MLA Handbook (7th Edition):
Tripoli, Paolo. “Chow hypersurfaces and realizability problems in tropical geometry.” 2017. Web. 23 Jul 2018.
Vancouver:
Tripoli P. Chow hypersurfaces and realizability problems in tropical geometry. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2018 Jul 23].
Available from: http://wrap.warwick.ac.uk/99839/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737741.
Council of Science Editors:
Tripoli P. Chow hypersurfaces and realizability problems in tropical geometry. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/99839/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737741
University of Warwick
15.
Jatuviriyapornchai, Watthanan.
Population dynamics and stochastic particle systems.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/99427/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737721
► Condensation is a special class of phase transition which has been observed throughout the natural and social sciences. The understanding of dynamics towards condensation on…
(more)
▼ Condensation is a special class of phase transition which has been observed throughout the natural and social sciences. The understanding of dynamics towards condensation on a mathematically rigorous level is currently a major research topic. Starting the system from homogeneous initial conditions, the time evolution of the condensed phase often exhibits an interesting coarsening phenomenon of mass transport between cluster sites. In this thesis, we study the coarsening dynamics in several condensing stochastic particle systems. First, we consider the single site dynamics in general stochastic particle systems of misanthrope type with bounded rates on a complete graph. In the limit of diverging system size, we establish convergence to a Markovian non-linear birth death chain, described by a mean-field equation also known from exchange-driven growth processes. Conservation of mass in the particle system leads to conservation of the first moment for the limiting dynamics, and to non-uniqueness of stationary measures. The proof is based on a coupling to branching processes via the graphical construction and establishing uniqueness of the solution for the limit dynamics. As particularly interesting examples we discuss the dynamics of two models that exhibit a condensation transition and their connection to exchange-driven growth processes. The first model is the zero-range process with bounded jump rates. It is well known that zero-range processes with decreasing jump rates exhibit a condensation transition under certain conditions. The mean-field limit of the single site dynamics leads to a non-linear birth death chain describing the coarsening behaviour. We introduce a size-biased version of the single site process, which provides an effective tool to analyse the dynamics of the condensed phase without finite size effects. The second model is the inclusion process, which has unbounded jump rates and also exhibits the condensation phenomenon. However, in this case, the mean-field equation is derived differently, and the single site process is in the form of a standard birth death chain. In addition to the site and size-biased processes, we derive some exact results on the system through duality. We compute the time dependent covariance using the self-duality of inclusion processes and a two-particle dual process. Our results are based on exact computations and are corroborated by detailed simulation data, which contribute to a rigorous understanding of the approach to stationarity in the thermodynamic limit of diverging system size and particle number.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Jatuviriyapornchai, W. (2017). Population dynamics and stochastic particle systems. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/99427/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737721
Chicago Manual of Style (16th Edition):
Jatuviriyapornchai, Watthanan. “Population dynamics and stochastic particle systems.” 2017. Doctoral Dissertation, University of Warwick. Accessed July 23, 2018.
http://wrap.warwick.ac.uk/99427/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737721.
MLA Handbook (7th Edition):
Jatuviriyapornchai, Watthanan. “Population dynamics and stochastic particle systems.” 2017. Web. 23 Jul 2018.
Vancouver:
Jatuviriyapornchai W. Population dynamics and stochastic particle systems. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2018 Jul 23].
Available from: http://wrap.warwick.ac.uk/99427/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737721.
Council of Science Editors:
Jatuviriyapornchai W. Population dynamics and stochastic particle systems. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/99427/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737721
University of Warwick
16.
Fatighenti, Enrico.
Hodge theory in Grassmannians.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/98276/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737688
► In this thesis we study several generalisations of the Griffiths’s residue technique. We first show how the deformation modules Ti of the affine cone over…
(more)
▼ In this thesis we study several generalisations of the Griffiths’s residue technique. We first show how the deformation modules Ti of the affine cone over a smooth projective variety X contain the Hodge groups of X as homogeneous slices. We discuss several applications, mainly in the Birational Geometry of Q-Fano threefolds. We then investigate the case of subvarieties of the Grassmannian Gr(k, n). For an hypersurfaces (or a complete intersection) X in the Grassmannian Gr(k, n) we are able to explicitly construct a Griffiths ring that allows us to compute all the Hodge groups Hp,q(X). We then apply our techniques to construct new interesting varieties in the Grassmannians, such as surfaces of general type with low invariants and Fano manifolds of K3-type.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Fatighenti, E. (2017). Hodge theory in Grassmannians. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/98276/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737688
Chicago Manual of Style (16th Edition):
Fatighenti, Enrico. “Hodge theory in Grassmannians.” 2017. Doctoral Dissertation, University of Warwick. Accessed July 23, 2018.
http://wrap.warwick.ac.uk/98276/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737688.
MLA Handbook (7th Edition):
Fatighenti, Enrico. “Hodge theory in Grassmannians.” 2017. Web. 23 Jul 2018.
Vancouver:
Fatighenti E. Hodge theory in Grassmannians. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2018 Jul 23].
Available from: http://wrap.warwick.ac.uk/98276/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737688.
Council of Science Editors:
Fatighenti E. Hodge theory in Grassmannians. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/98276/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737688
University of Warwick
17.
Tawn, Nicholas.
Towards optimality of the parallel tempering algorithm.
Degree: PhD, 2017, University of Warwick
URL: http://wrap.warwick.ac.uk/99796/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737740
► Markov Chain Monte Carlo (MCMC) techniques for sampling from complex probability distributions have become mainstream. Big data and high model complexity demand more scalable and…
(more)
▼ Markov Chain Monte Carlo (MCMC) techniques for sampling from complex probability distributions have become mainstream. Big data and high model complexity demand more scalable and robust algorithms. A famous problem with MCMC is making it robust to situations when the target distribution is multi-modal. In such cases the algorithm can become trapped in a subset of the state space and fail to escape during the entirety of the run of the algorithm. This non-exploration of the state space results in highly biased sample output. Simulated (ST) and Parallel (PT) Tempering algorithms are typically used to address multi-modality problems. These methods flatten out the target distribution using a temperature schedule. This allows the Markov chain to move freely around the state space and explore all regions of significant mass. This thesis explores two new ideas to improve the scalability of the PT algorithm. These are implemented in prototype algorithms, QuanTA and HAT, which are accompanied by supportive theoretical optimal scaling results. QuanTA focuses on improving transfer speed of the hot state mixing information to the target cold state. The associated scaling result for QuanTA shows that under mild conditions the QuanTA approach admits a higher order temperature spacing than the PT algorithm. HAT focuses on preserving modal weight through the temperature schedule. This is an issue that can lead to critically poor performance of the PT approach. The associated optimal scaling result is useful from a practical perspective. The result also challenges the notion that without modal weight preservation tempering schedules can be selected based on swap acceptance rates; an idea repeatedly used in the current literature. The new algorithms are prototype designs and have clear limitations. However, the impressive empirical performance of these new algorithms, together with supportive theory, illustrate their substantial improvement over existing methodology.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tawn, N. (2017). Towards optimality of the parallel tempering algorithm. (Doctoral Dissertation). University of Warwick. Retrieved from http://wrap.warwick.ac.uk/99796/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737740
Chicago Manual of Style (16th Edition):
Tawn, Nicholas. “Towards optimality of the parallel tempering algorithm.” 2017. Doctoral Dissertation, University of Warwick. Accessed July 23, 2018.
http://wrap.warwick.ac.uk/99796/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737740.
MLA Handbook (7th Edition):
Tawn, Nicholas. “Towards optimality of the parallel tempering algorithm.” 2017. Web. 23 Jul 2018.
Vancouver:
Tawn N. Towards optimality of the parallel tempering algorithm. [Internet] [Doctoral dissertation]. University of Warwick; 2017. [cited 2018 Jul 23].
Available from: http://wrap.warwick.ac.uk/99796/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737740.
Council of Science Editors:
Tawn N. Towards optimality of the parallel tempering algorithm. [Doctoral Dissertation]. University of Warwick; 2017. Available from: http://wrap.warwick.ac.uk/99796/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737740
University of Birmingham
18.
Zhang, Guohan.
Complementarity problems, variational inequalities and extended Lorentz cones.
Degree: PhD, 2017, University of Birmingham
URL: http://etheses.bham.ac.uk/8003/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738121
► In this thesis, we introduced the concept of extended Lorentz cones. We discussed the solvability of variational inequalities and complementarity problems associated with an unrelated…
(more)
▼ In this thesis, we introduced the concept of extended Lorentz cones. We discussed the solvability of variational inequalities and complementarity problems associated with an unrelated closed convex cone. This cone does not have to be an isotone projection cone. We showed that the solution of variational inequalities and complementarity problems can be reached as a limit of a sequence defined in an ordered space which is ordered by extended Lorentz cone. Moreover, we applied our results in game theory and conic optimization problems. We also discussed the positive operators. We showed necessary and sufficient conditions under which a linear operator is a positive operator of extended Lorentz cone. We also showed sufficient and necessary conditions under which a linear operator in a specific form is a positive operator.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zhang, G. (2017). Complementarity problems, variational inequalities and extended Lorentz cones. (Doctoral Dissertation). University of Birmingham. Retrieved from http://etheses.bham.ac.uk/8003/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738121
Chicago Manual of Style (16th Edition):
Zhang, Guohan. “Complementarity problems, variational inequalities and extended Lorentz cones.” 2017. Doctoral Dissertation, University of Birmingham. Accessed July 23, 2018.
http://etheses.bham.ac.uk/8003/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738121.
MLA Handbook (7th Edition):
Zhang, Guohan. “Complementarity problems, variational inequalities and extended Lorentz cones.” 2017. Web. 23 Jul 2018.
Vancouver:
Zhang G. Complementarity problems, variational inequalities and extended Lorentz cones. [Internet] [Doctoral dissertation]. University of Birmingham; 2017. [cited 2018 Jul 23].
Available from: http://etheses.bham.ac.uk/8003/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738121.
Council of Science Editors:
Zhang G. Complementarity problems, variational inequalities and extended Lorentz cones. [Doctoral Dissertation]. University of Birmingham; 2017. Available from: http://etheses.bham.ac.uk/8003/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738121
Cardiff University
19.
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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Vronskaya M. Stability of singular spectrum analysis and causality in time series. [Internet] [Doctoral dissertation]. Cardiff University; 2013. [cited 2018 Jul 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
20.
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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Hao Y. Solving Eigenproblems with application in collapsible channel flows. [Internet] [Doctoral dissertation]. University of Glasgow; 2013. [cited 2018 Jul 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
University of Birmingham
21.
Jones, Daniel Lewis.
Special and structured matrices in max-plus algebra.
Degree: PhD, 2017, University of Birmingham
URL: http://etheses.bham.ac.uk/7527/
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715663
► The aim of this thesis is to present efficient (strongly polynomial) methods and algorithms for problems in maxalgebra when certain matrices have special entries or…
(more)
▼ The aim of this thesis is to present efficient (strongly polynomial) methods and algorithms for problems in maxalgebra when certain matrices have special entries or are structured. First, we describe all solutions to a one-sided parametrised system. Next, we consider special cases of two-sided systems of equations/inequalities. Usually, we describe a set of generators of all solutions but sometimes we are satisfied with finding a non-trivial solution or being able to say something meaningful about a non-trivial solution should it exist. We look at special cases of the generalised eigenproblem, describing the full spectrum usually. Finally, we prove some results on 2x2 matrix roots and generalise these results to a class of nxn matrices. Main results include: a description of all solutions to the two-dimensional generalised eigenproblem; observations about a non-trivial solution (should it exist) to essential/minimally active two-sided systems of equations; the full spectrum of the generalised eigenproblem when one of the matrices is an outer-product; the unique candidate for the generalised eigenproblem when the difference of two matrices is symmetric and has a saddle point and finally we explicitly say when a 2x2 matrix has a kth root for a fixed positive integer k.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Jones, D. L. (2017). Special and structured matrices in max-plus algebra. (Doctoral Dissertation). University of Birmingham. Retrieved from http://etheses.bham.ac.uk/7527/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715663
Chicago Manual of Style (16th Edition):
Jones, Daniel Lewis. “Special and structured matrices in max-plus algebra.” 2017. Doctoral Dissertation, University of Birmingham. Accessed July 23, 2018.
http://etheses.bham.ac.uk/7527/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715663.
MLA Handbook (7th Edition):
Jones, Daniel Lewis. “Special and structured matrices in max-plus algebra.” 2017. Web. 23 Jul 2018.
Vancouver:
Jones DL. Special and structured matrices in max-plus algebra. [Internet] [Doctoral dissertation]. University of Birmingham; 2017. [cited 2018 Jul 23].
Available from: http://etheses.bham.ac.uk/7527/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715663.
Council of Science Editors:
Jones DL. Special and structured matrices in max-plus algebra. [Doctoral Dissertation]. University of Birmingham; 2017. Available from: http://etheses.bham.ac.uk/7527/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715663
Cardiff University
22.
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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Holland JW. Properties of the operator product expansion in quantum field theory. [Internet] [Doctoral dissertation]. Cardiff University; 2013. [cited 2018 Jul 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
23.
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…
(more)
▼ 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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Wang W. Aspects of wave propagation in anisotropic elastic half-spaces and plates. [Internet] [Doctoral dissertation]. Keele University; 2013. [cited 2018 Jul 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
24.
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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Li B. Mathematical modelling of aortic dissection. [Internet] [Doctoral dissertation]. University of Glasgow; 2013. [cited 2018 Jul 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
Cardiff University
25.
Padungwech, Wasin.
Heuristic algorithms for dynamic capacitated arc routing.
Degree: PhD, 2018, Cardiff University
URL: http://orca.cf.ac.uk/111021/
► This thesis concerns the capacitated arc routing problem (CARP), which can be used as a model of various real-life scenarios such as rubbish collection, snow…
(more)
▼ This thesis concerns the capacitated arc routing problem (CARP), which can be used as a model of various real-life scenarios such as rubbish collection, snow ploughing, and other situations where an emphasis is placed on providing a certain service along streets. The goal of the CARP is to find a minimum-cost set of routes such that (i) each route starts and ends at the depot, (ii) each task is serviced in one of the routes, and (iii) the total demand in each route does not exceed the capacity. Until recently, the study of the CARP is concentrated on its "static" version, that is, it is assumed that the problem remains unchanged after vehicles start their journeys. However, with today's communication technology, a route planner and drivers can communicate with each other in real time, hence the possibility of amending vehicle routes if deemed necessary or appropriate for changes that may occur in the problem. This motivates the study of a dynamic CARP. This thesis focusses on one type of change in the dynamic CARP, namely the appearance of new tasks. To ensure that a service can be performed smoothly, the ability to update a solution quickly is often preferable to achieving optimality with an excessive amount of computational effort. For this reason, we opt to develop a dynamic CARP solver based on heuristic algorithms. An investigation is conducted to gain more insights about what makes an algorithm improve a solution quickly. Furthermore, factors in the dynamic CARP beyond a solution-seeking algorithm are investigated. This includes the frequency of updating the solution and the idea of instructing vehicles to wait for additional tasks at certain locations. Efforts are focussed on reducing the total distance at the end of the service while ensuring that the service completion time is not excessive.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Padungwech, W. (2018). Heuristic algorithms for dynamic capacitated arc routing. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/111021/
Chicago Manual of Style (16th Edition):
Padungwech, Wasin. “Heuristic algorithms for dynamic capacitated arc routing.” 2018. Doctoral Dissertation, Cardiff University. Accessed July 23, 2018.
http://orca.cf.ac.uk/111021/.
MLA Handbook (7th Edition):
Padungwech, Wasin. “Heuristic algorithms for dynamic capacitated arc routing.” 2018. Web. 23 Jul 2018.
Vancouver:
Padungwech W. Heuristic algorithms for dynamic capacitated arc routing. [Internet] [Doctoral dissertation]. Cardiff University; 2018. [cited 2018 Jul 23].
Available from: http://orca.cf.ac.uk/111021/.
Council of Science Editors:
Padungwech W. Heuristic algorithms for dynamic capacitated arc routing. [Doctoral Dissertation]. Cardiff University; 2018. Available from: http://orca.cf.ac.uk/111021/
University of Greenwich
26.
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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 July 23, 2018.
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 Jul 2018.
Vancouver:
Lebon GSB. Unstructured finite volume algorithms for compressible multiphase flow. [Internet] [Doctoral dissertation]. University of Greenwich; 2011. [cited 2018 Jul 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
27.
Tian, Na.
Novel optimisation methods for numerical inverse problems.
Degree: phd, School of Computing and Mathematical Sciences, 2011, University of Greenwich
URL: http://gala.gre.ac.uk/9099/
► Inverse problems involve the determination of one or more unknown quantities usually appearing in the mathematical formulation of a physical problem. These unknown quantities may…
(more)
▼ Inverse problems involve the determination of one or more unknown quantities usually appearing in the mathematical formulation of a physical problem. These unknown quantities may be boundary heat flux, various source terms, thermal and material properties, boundary shape and size. Solving inverse problems requires additional information through in-situ data measurements of the field variables of the physical problems. These problems are also ill-posed because the solution itself is sensitive to random errors in the measured input data. Regularisation techniques are usually used in order to deal with the instability of the solution. In the past decades, many methods based on the nonlinear least squares model, both deterministic (CGM) and stochastic (GA, PSO), have been investigated for numerical inverse problems.
The goal of this thesis is to examine and explore new techniques for numerical inverse problems. The background theory of population-based heuristic algorithm known as quantum-behaved particle swarm optimisation (QPSO) is re-visited and examined. To enhance the global search ability of QPSO for complex multi-modal problems, several modifications to QPSO are proposed. These include perturbation operation, Gaussian mutation and ring topology model. Several parameter selection methods for these algorithms are proposed. Benchmark functions were used to test the performance of the modified algorithms. To address the high computational cost of complex engineering optimisation problems, two parallel models of the QPSO (master-slave, static subpopulation) were developed for different distributed systems. A hybrid method, which makes use of deterministic (CGM) and stochastic (QPSO) methods, is proposed to improve the estimated solution and the performance of the algorithms for solving the inverse problems.
Finally, the proposed methods are used to solve typical problems as appeared in many research papers. The numerical results demonstrate the feasibility and efficiency of QPSO and the global search ability and stability of the modified versions of QPSO. Two novel methods of providing initial guess to CGM with approximated data from QPSO are also proposed for use in the hybrid method and were applied to estimate heat fluxes and boundary shapes. The simultaneous estimation of temperature dependent thermal conductivity and heat capacity was addressed by using QPSO with Gaussian mutation. This combination provides a stable algorithm even with noisy measurements. Comparison of the performance between different methods for solving inverse problems is also presented in this thesis.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tian, N. (2011). Novel optimisation methods for numerical inverse problems. (Doctoral Dissertation). University of Greenwich. Retrieved from http://gala.gre.ac.uk/9099/
Chicago Manual of Style (16th Edition):
Tian, Na. “Novel optimisation methods for numerical inverse problems.” 2011. Doctoral Dissertation, University of Greenwich. Accessed July 23, 2018.
http://gala.gre.ac.uk/9099/.
MLA Handbook (7th Edition):
Tian, Na. “Novel optimisation methods for numerical inverse problems.” 2011. Web. 23 Jul 2018.
Vancouver:
Tian N. Novel optimisation methods for numerical inverse problems. [Internet] [Doctoral dissertation]. University of Greenwich; 2011. [cited 2018 Jul 23].
Available from: http://gala.gre.ac.uk/9099/.
Council of Science Editors:
Tian N. Novel optimisation methods for numerical inverse problems. [Doctoral Dissertation]. University of Greenwich; 2011. Available from: http://gala.gre.ac.uk/9099/
University of Greenwich
28.
Than Soe, Muang.
Vibration-based finite element model updating and structural damage identification.
Degree: phd, School of Engineering, 2013, University of Greenwich
URL: http://gala.gre.ac.uk/11451/
► Damage and material deterioration could lead to structural failure with unknown consequences. Structural health monitoring strategy based on vibration measurements for existing aging structures offers…
(more)
▼ Damage and material deterioration could lead to structural failure with unknown consequences. Structural health monitoring strategy based on vibration measurements for existing aging structures offers a promising technique for effectively managing the deteriorating structures. The main objectives of this research are to develop a procedure for finite element model updating by using incomplete modal data identified from vibration measurements, to develop real time structural damage detecting method by directly using vibration measurements and then identify the damage at detailed location and extend in the structure on the basis of the validated numerical model.
A steel frame model structure was constructed in the laboratory for finite element model updating and structural damage detection. Forced vibration testing was undertaken on the model structure and dynamic response such as accelerations were measured by using sensors installed. Modal analyses are then carried out to identify modal parameters such as frequencies, mode shapes and damping from the vibration measurements. Structural damage scenarios were simulated by breaking bracing members of the model structure, and modal parameter of the damaged structures were also identified and analysed.
An effective approach for directly updating finite element model from measured incomplete modal data with a regularised iterative algorithm is then presented. The exact relationship between the perturbation of structural parameters and the modal properties of the dynamic structure is developed. Numerical simulation investigations and experimental study of a laboratory tested space steel frame model and practical application to the Canton Tower benchmark problem are undertaken to verify the accuracy and effectiveness of the proposed model updating method.
Finally, a new approach for real time structural damage detection by using acceleration measurements is presented. Structural damage is characterised at element level by introducing damage parameters which can indicate the location and severity of damage in the structure. The relationship between the damage parameters and the measured dynamic response is then established from the governing equation of the dynamic structure. Numerical examples of cantilever beams, plane frame, and braced frames are adopted to demonstrate the effectiveness of the proposed method. The new proposed technique performs well and produces stable and reliable results, which could be used for real time damage assessment during the event of earthquake and explosion.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Than Soe, M. (2013). Vibration-based finite element model updating and structural damage identification. (Doctoral Dissertation). University of Greenwich. Retrieved from http://gala.gre.ac.uk/11451/
Chicago Manual of Style (16th Edition):
Than Soe, Muang. “Vibration-based finite element model updating and structural damage identification.” 2013. Doctoral Dissertation, University of Greenwich. Accessed July 23, 2018.
http://gala.gre.ac.uk/11451/.
MLA Handbook (7th Edition):
Than Soe, Muang. “Vibration-based finite element model updating and structural damage identification.” 2013. Web. 23 Jul 2018.
Vancouver:
Than Soe M. Vibration-based finite element model updating and structural damage identification. [Internet] [Doctoral dissertation]. University of Greenwich; 2013. [cited 2018 Jul 23].
Available from: http://gala.gre.ac.uk/11451/.
Council of Science Editors:
Than Soe M. Vibration-based finite element model updating and structural damage identification. [Doctoral Dissertation]. University of Greenwich; 2013. Available from: http://gala.gre.ac.uk/11451/
University of Greenwich
29.
Lai, Liang Simon.
Defect correction methods for computational aeroacoustics.
Degree: phd, School of Computing and Mathematical Sciences, 2013, University of Greenwich
URL: http://gala.gre.ac.uk/11452/
► The idea of Defect Correction Method (DCM) has been around for a long time. It can be used in a number of different ways and…
(more)
▼ The idea of Defect Correction Method (DCM) has been around for a long time. It can be used in a number of different ways and can be applied to solve various linear and non-linear problems. Most defect correction related methods were used in conjunction with discretisation methods and two-level multigrid methods. This thesis examines how various iterative methods, both for linear and nonlinear problems, may be built into a unified framework through the use of defect correction. The framework is extended to the area of Computational Aeroacoustics (CAA) where sound waves generated by the pressure fluctuations are typically several orders of magnitude smaller than the pressure variations in the main flow field that accounts for flow acceleration. A decomposition of variables is used to break down the components of a typical flow variable into (1) the mean flow, (2) flow perturbations or aerodynamic sources of sound, and (3) the acoustic perturbation. The framework as discussed in this thesis would incorporate such variable decomposition. The basic principle of DCM can be applied to recover the propagating acoustic perturbation through a coupling technique. This provides an excellent concept in the re-use of existing commercial CFD software based on the framework and in the retrieval of acoustic pressure. Numerical examples demonstrating the defect correction framework for a typical car sun-roof problem was examined with promising numerical results. To this end the complete process of coupling Reynolds average Navier-Stokes and the Helmholtz equation is also presented using the DCM framework.
The DCM framework is also extended to handle higher order numerical methods for the numerical solutions of partial differential equations leading to an easy re-use of existing software approximating derivatives with a lower order discretisation. Numerical experiments were performed to demonstrate the capability of the DCM framework. It is also used to a simplified 2-D problems aiming at the understanding of Large Eddy Simulation (LES) and filtering techniques. To this end the framework of DCM leads to an efficient and robust software implementation for many CFD and aeroacoustic computation in a simple nutshell.
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Lai, L. S. (2013). Defect correction methods for computational aeroacoustics. (Doctoral Dissertation). University of Greenwich. Retrieved from http://gala.gre.ac.uk/11452/
Chicago Manual of Style (16th Edition):
Lai, Liang Simon. “Defect correction methods for computational aeroacoustics.” 2013. Doctoral Dissertation, University of Greenwich. Accessed July 23, 2018.
http://gala.gre.ac.uk/11452/.
MLA Handbook (7th Edition):
Lai, Liang Simon. “Defect correction methods for computational aeroacoustics.” 2013. Web. 23 Jul 2018.
Vancouver:
Lai LS. Defect correction methods for computational aeroacoustics. [Internet] [Doctoral dissertation]. University of Greenwich; 2013. [cited 2018 Jul 23].
Available from: http://gala.gre.ac.uk/11452/.
Council of Science Editors:
Lai LS. Defect correction methods for computational aeroacoustics. [Doctoral Dissertation]. University of Greenwich; 2013. Available from: http://gala.gre.ac.uk/11452/
University of Greenwich
30.
Tilford, Timothy James.
Numerical analysis of microwave processing problems using a multidomain solver approach.
Degree: phd, Faculty of Architecture, Computing & Humanities, 2013, University of Greenwich
URL: http://gala.gre.ac.uk/11941/
► This work outlines the process undertaken in the formulation and validation of a numerical model for analysis of practical microwave processing problems. The proposed model…
(more)
▼ This work outlines the process undertaken in the formulation and validation of a numerical model for analysis of practical microwave processing problems. The proposed model adopts a novel multi-domain Eulerian-Lagrangian approach to the problem, defining two discrete numerical domains coupled through a set of data transfer algorithms. One of the numerical domains is defined for analysis of electromagnetic field distribution while the other is used for analysis of the thermophysical aspects of the problem. The thermophysical domain is restricted to the load being processed and is discretised in an Eulerian manner using an unstructured mesh for solution using a finite volume approach. The electromagnetic domain is discretised using a tensor-product rectilinear structured mesh for solution of Maxwell’s equations using a Yee finite difference time domain approach. The thermophysical load is represented within the electromagnetic domain through a mapped Lagrangian complex permittivity distribution rather than being defined explicitly. The two domains are coupled through mapping routines capable of defining the complex permittivity distribution within the electromagnetic domain and transferring the calculated power density distribution into the thermophysical domain. This interdomain coupling allows the meshes in the two domains to be non coincident, enabling the discretisation of the two domains to be completely independent of each other.
This approach to analysis of coupled microwave processing problems is novel and provides a number of significant benefits over conventional single-domain methods. The primary benefit of the approach is that the electromagnetic and thermophysical parts of the analysis can be handled by different solvers using differing meshes. This is a very significant advance as the optimal approach to solving one of the parts be be extremely inefficient or indeed unfeasible for the other. The approach allows electromagnetic fields irradiating complex geometries placed inside a rectilinear microwave ovens to be analyses using a tensor product solver. The solution of the electromagnetic field distribution is typically the most computationally expensive part of a coupled solution of microwave heating. The ability to use a Yee finite difference solver rather than a conformal FDTD or finite element approach provides a very significant reduction in computational expense, enabling more complex analyses to be performed. Solution of thermophysical aspects of the problem are most effectively tackled using an unstructured spatial discretisation in cases with complex geometries. The adoption of an unstructured finite volume approach for the thermophysical part of the analysis provides an analysis capability far beyond that of the finite difference approach typically used in analyses with a finite difference electromagnetic solver.
Further benefits stem from the inherent capability to alter the discretisation of the electromagnetic domain independently of the thermophysical domain, enabling cases with…
Subjects/Keywords: QA Mathematics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tilford, T. J. (2013). Numerical analysis of microwave processing problems using a multidomain solver approach. (Doctoral Dissertation). University of Greenwich. Retrieved from http://gala.gre.ac.uk/11941/
Chicago Manual of Style (16th Edition):
Tilford, Timothy James. “Numerical analysis of microwave processing problems using a multidomain solver approach.” 2013. Doctoral Dissertation, University of Greenwich. Accessed July 23, 2018.
http://gala.gre.ac.uk/11941/.
MLA Handbook (7th Edition):
Tilford, Timothy James. “Numerical analysis of microwave processing problems using a multidomain solver approach.” 2013. Web. 23 Jul 2018.
Vancouver:
Tilford TJ. Numerical analysis of microwave processing problems using a multidomain solver approach. [Internet] [Doctoral dissertation]. University of Greenwich; 2013. [cited 2018 Jul 23].
Available from: http://gala.gre.ac.uk/11941/.
Council of Science Editors:
Tilford TJ. Numerical analysis of microwave processing problems using a multidomain solver approach. [Doctoral Dissertation]. University of Greenwich; 2013. Available from: http://gala.gre.ac.uk/11941/
◁ [1] [2] [3] [4] [5] … [65] ▶
. 
Open Access Theses and Dissertations