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University of Canterbury
1.
Saharan, Sabariah.
A new genetic algorithm based clustering for binary and imbalanced class data sets.
Degree: phd, College of Engineering, 2016, University of Canterbury
URL: http://eprints.uthm.edu.my/id/eprint/10258/ 
► This research was initially driven by the lack of clustering algorithms that specifically focus on binary data. To overcome this gap in knowledge, a promising…
(more)
▼ This research was initially driven by the lack of clustering algorithms that specifically focus
on binary data. To overcome this gap in knowledge, a promising technique for analysing this
type of data became the main subject in this research, namely Genetic Algorithm (GA). This
type of algorithm has an intrinsic search parallelism that avoids getting stuck at the local
optima and poor initialization. For the purpose of this research, GA was combined with the
Incremental K-means (IKM) algorithm to cluster the binary data streams. However, prior
to this proposed method, a well-known GA based clustering method, GCUK was applied to
gauge the performance of this algorithm to cluster the binary data, with new application
for binary data set. Subsequently, this led to a proposed new method known as Genetic
Algorithm-Incremental K-means (GAIKM) with the objective function based on a few suffi-
cient statistics that may be easily and quickly calculated on binary numbers. Different from
the other clustering algorithms for binary data, this proposed method has an advantage in
terms of fast convergence by implementing the IKM. Additionally, the utilization of GA pro-
vides a continuous process of searching for the best solutions, that can escape from being
trapped at the local optima like the other clustering methods. The results show that GAIKM
is an efficient and effective new clustering algorithm compared to the clustering algorithms
and to the IKM itself. The other main contribution in this research is the ability of the pro-
posed GAIKM to cluster imbalanced data sets, where standard clustering algorithms cannot
simply be applied to this data as they could cause misclassification results. In conclusion,
the GAIKM outperformed other clustering algorithms, and paves the way for future research
in missing data and outliers and also by implementing the GA multi-objective optimization.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Saharan, S. (2016). A new genetic algorithm based clustering for binary and imbalanced class data sets. (Doctoral Dissertation). University of Canterbury. Retrieved from http://eprints.uthm.edu.my/id/eprint/10258/
Chicago Manual of Style (16th Edition):
Saharan, Sabariah. “A new genetic algorithm based clustering for binary and imbalanced class data sets.” 2016. Doctoral Dissertation, University of Canterbury. Accessed February 27, 2021.
http://eprints.uthm.edu.my/id/eprint/10258/.
MLA Handbook (7th Edition):
Saharan, Sabariah. “A new genetic algorithm based clustering for binary and imbalanced class data sets.” 2016. Web. 27 Feb 2021.
Vancouver:
Saharan S. A new genetic algorithm based clustering for binary and imbalanced class data sets. [Internet] [Doctoral dissertation]. University of Canterbury; 2016. [cited 2021 Feb 27].
Available from: http://eprints.uthm.edu.my/id/eprint/10258/.
Council of Science Editors:
Saharan S. A new genetic algorithm based clustering for binary and imbalanced class data sets. [Doctoral Dissertation]. University of Canterbury; 2016. Available from: http://eprints.uthm.edu.my/id/eprint/10258/
2.
Zainol, Norfazilah.
The comparative study of model-based and apprearance based gait recognition for leave bag behind.
Degree: mphil, Faculty of Computer Science and Information Technology, 2018, Universiti Tun Hussein Onn Malaysia
URL: http://eprints.uthm.edu.my/id/eprint/12110/
► Recently, many deterministic mathematical models such as ordinary differential equations have been extended to fractional models, which are transformed using fractional differential equations. It was…
(more)
▼ Recently, many deterministic mathematical models such as ordinary differential
equations have been extended to fractional models, which are transformed using
fractional differential equations. It was believed that these fractional models are more
realistic to represent the daily life phenomena. The main focus of this report is to
extend the model of a predator-prey and the SIR epidemic models to fractional model.
More specifically, the fractional predator-prey model which depend on the availability
of a biotic resources was discussed. On the other hand, fractional SIR epidemic
model with sub-optimal immunity, nonlinear incidence and saturated recovery rate
was also discussed. The fractional ordinary differential equations were defined in
the sense of the Caputo derivative. Stability analysis of the equilibrium points of the
models for the fractional models were analyzed. Furthermore, the Hopf bifurcation
analysis of each model was investigated . The result obtained showed that the model
undergo Hopf bifurcation for some values. Throughout the project, the Adams-type
predictor-corrector method to obtain the numerical solutions of the fractional models
was applied. All computations were done by using mathematical software, Maple 18.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Zainol, N. (2018). The comparative study of model-based and apprearance based gait recognition for leave bag behind. (Masters Thesis). Universiti Tun Hussein Onn Malaysia. Retrieved from http://eprints.uthm.edu.my/id/eprint/12110/
Chicago Manual of Style (16th Edition):
Zainol, Norfazilah. “The comparative study of model-based and apprearance based gait recognition for leave bag behind.” 2018. Masters Thesis, Universiti Tun Hussein Onn Malaysia. Accessed February 27, 2021.
http://eprints.uthm.edu.my/id/eprint/12110/.
MLA Handbook (7th Edition):
Zainol, Norfazilah. “The comparative study of model-based and apprearance based gait recognition for leave bag behind.” 2018. Web. 27 Feb 2021.
Vancouver:
Zainol N. The comparative study of model-based and apprearance based gait recognition for leave bag behind. [Internet] [Masters thesis]. Universiti Tun Hussein Onn Malaysia; 2018. [cited 2021 Feb 27].
Available from: http://eprints.uthm.edu.my/id/eprint/12110/.
Council of Science Editors:
Zainol N. The comparative study of model-based and apprearance based gait recognition for leave bag behind. [Masters Thesis]. Universiti Tun Hussein Onn Malaysia; 2018. Available from: http://eprints.uthm.edu.my/id/eprint/12110/
3.
Disina, Abdulkadir Hassan.
Dynamic key scheduling algorithm for block ciphers using quasigroup string transformation.
Degree: phd, Faculty of Computer Science and Information Technology, 2018, Universiti Tun Hussein Onn Malaysia
URL: http://eprints.uthm.edu.my/id/eprint/12213/
► Cryptographic ciphers depend on how quickly the key affects the output of the ciphers (ciphertext). Keys are traditionally generated from small size input (seed) to…
(more)
▼ Cryptographic ciphers depend on how quickly the key affects the output of the ciphers (ciphertext). Keys are traditionally generated from small size input (seed) to a bigger size random key(s). Key scheduling algorithm (KSA) is the mechanism that generates and schedules all sub-keys for each round of encryption. Researches have suggested that sub-keys should be generated separately to avoid related-key attack. Similarly, the key space should be disproportionately large to resist any attack on the secret key. To archive that, some algorithms adopt the use of matrixes such as quasigroup, Hybrid cubes and substitution box (S-box) to generate the encryption keys. Quasigroup has other algebraic property called “Isotophism”, which literally means Different quasigroups that has the same order of elements but different arrangements can be generated from the existing one. This research proposed a Dynamic Key Scheduling Algorithm (KSA) using isotope of a quasigroup as the dynamic substitution table. A method of generating isotope from a non-associative quasigroup using one permutation with full inheritance is achieved. The generic quasigroup string transformation has been analyzed and it is found to be vulnerable to ciphertext only attack which eventually led to the proposal of a new quasigroup string transformation in this research to assess its strength as it has never been analyzed nor properly implemented before. Based on the dynamic shapeless quasigroup and the proposed new string transformation, a Dynamic Key Scheduling Algorithm (DKSA) is developed. To validate the findings, non-associativity of the generated isotopes has been tested and the generated isotopes appeared to be non-associative. Furthermore, the proposed KSA algorithm has been validated using the randomness test proposed and recommended by NIST, avalanche test and has achieved remarkable result of 94%, brute force and correlation assessment test with -0.000449 correlations. It was fully implemented in a modified Rijndael block cipher to validate it performance and it has produced a remarkable result of 3.35332 entropy.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Disina, A. H. (2018). Dynamic key scheduling algorithm for block ciphers using quasigroup string transformation. (Doctoral Dissertation). Universiti Tun Hussein Onn Malaysia. Retrieved from http://eprints.uthm.edu.my/id/eprint/12213/
Chicago Manual of Style (16th Edition):
Disina, Abdulkadir Hassan. “Dynamic key scheduling algorithm for block ciphers using quasigroup string transformation.” 2018. Doctoral Dissertation, Universiti Tun Hussein Onn Malaysia. Accessed February 27, 2021.
http://eprints.uthm.edu.my/id/eprint/12213/.
MLA Handbook (7th Edition):
Disina, Abdulkadir Hassan. “Dynamic key scheduling algorithm for block ciphers using quasigroup string transformation.” 2018. Web. 27 Feb 2021.
Vancouver:
Disina AH. Dynamic key scheduling algorithm for block ciphers using quasigroup string transformation. [Internet] [Doctoral dissertation]. Universiti Tun Hussein Onn Malaysia; 2018. [cited 2021 Feb 27].
Available from: http://eprints.uthm.edu.my/id/eprint/12213/.
Council of Science Editors:
Disina AH. Dynamic key scheduling algorithm for block ciphers using quasigroup string transformation. [Doctoral Dissertation]. Universiti Tun Hussein Onn Malaysia; 2018. Available from: http://eprints.uthm.edu.my/id/eprint/12213/
4.
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/id/eprint/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
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APA ·
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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/id/eprint/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 February 27, 2021.
http://eprints.uthm.edu.my/id/eprint/4652/.
MLA Handbook (7th Edition):
Arbaiy, Nureize. “Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications.” 2012. Web. 27 Feb 2021.
Vancouver:
Arbaiy N. Satisficing-based formulation of fuzzy random multi-criteria programming models in production applications. [Internet] [Doctoral dissertation]. Waseda University; 2012. [cited 2021 Feb 27].
Available from: http://eprints.uthm.edu.my/id/eprint/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/id/eprint/4652/
5.
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/id/eprint/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
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APA ·
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MLA ·
Vancouver ·
CSE |
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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/id/eprint/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 February 27, 2021.
http://eprints.uthm.edu.my/id/eprint/8870/.
MLA Handbook (7th Edition):
Chieng, Hock Hung. “A genetic simplified swarm algorithm for optimizing n- cities open loop travelling salesman problem.” 2016. Web. 27 Feb 2021.
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 2021 Feb 27].
Available from: http://eprints.uthm.edu.my/id/eprint/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/id/eprint/8870/
6.
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/id/eprint/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
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APA ·
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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/id/eprint/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 February 27, 2021.
http://eprints.uthm.edu.my/id/eprint/8882/.
MLA Handbook (7th Edition):
Anwar Lashari, Saima. “Mammogram images classification based on fuzzy soft set.” 2016. Web. 27 Feb 2021.
Vancouver:
Anwar Lashari S. Mammogram images classification based on fuzzy soft set. [Internet] [Doctoral dissertation]. Universiti Tun Hussein Onn Malaysia; 2016. [cited 2021 Feb 27].
Available from: http://eprints.uthm.edu.my/id/eprint/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/id/eprint/8882/
7.
Ahmad Basri, NurAin Zafirah.
Construction of fuzzy control charts by using triangular and gaussian fuzzy numbers for solder paste thickness.
Degree: mphil, Faculty of Applied Science and Technology, 2018, Universiti Tun Hussein Onn Malaysia
URL: http://eprints.uthm.edu.my/id/eprint/12622/
► Control chart is one of the seven problem solving tools in Statistical Process Control (SPC) and become a very popular technique in improving productivity, preventing…
(more)
▼ Control chart is one of the seven problem solving tools in Statistical Process Control
(SPC) and become a very popular technique in improving productivity, preventing
defects and avoid purposeless process adjustment. Real data or problems nowadays
are too complicated to handle and the difficulty involves with the level of uncertainty
which might come from human, measurement devices or environmental conditions.
This study aims to generate fuzzy numbers by using triangular and Gaussian
approaches and to analyse the algorithm of fuzzy control charts by using α-cut and to
analyse the algorithm of traditional control charts of
-R and
-S towards the solder
paste thickness of integrated circuit data. The fuzzy numbers were generated by
using random number between 0 to 1.2% for each observation. Next, performance of
these control charts are compared by using average run length (ARL) to select the
best chart to control the production process. Results showed that the new fuzzy
control charts by using Gaussian fuzzy numbers are the best chart in monitoring the
solder paste thickness showed by the lowest value of ARL compared to fuzzy control
charts by using triangular fuzzy numbers and traditional control charts. Therefore,
this fuzzy control charts by using Gaussian fuzzy numbers can be used to monitor the
quality of a product.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
Ahmad Basri, N. Z. (2018). Construction of fuzzy control charts by using triangular and gaussian fuzzy numbers for solder paste thickness. (Masters Thesis). Universiti Tun Hussein Onn Malaysia. Retrieved from http://eprints.uthm.edu.my/id/eprint/12622/
Chicago Manual of Style (16th Edition):
Ahmad Basri, NurAin Zafirah. “Construction of fuzzy control charts by using triangular and gaussian fuzzy numbers for solder paste thickness.” 2018. Masters Thesis, Universiti Tun Hussein Onn Malaysia. Accessed February 27, 2021.
http://eprints.uthm.edu.my/id/eprint/12622/.
MLA Handbook (7th Edition):
Ahmad Basri, NurAin Zafirah. “Construction of fuzzy control charts by using triangular and gaussian fuzzy numbers for solder paste thickness.” 2018. Web. 27 Feb 2021.
Vancouver:
Ahmad Basri NZ. Construction of fuzzy control charts by using triangular and gaussian fuzzy numbers for solder paste thickness. [Internet] [Masters thesis]. Universiti Tun Hussein Onn Malaysia; 2018. [cited 2021 Feb 27].
Available from: http://eprints.uthm.edu.my/id/eprint/12622/.
Council of Science Editors:
Ahmad Basri NZ. Construction of fuzzy control charts by using triangular and gaussian fuzzy numbers for solder paste thickness. [Masters Thesis]. Universiti Tun Hussein Onn Malaysia; 2018. Available from: http://eprints.uthm.edu.my/id/eprint/12622/
8.
Alwiya, Awatf.
Mathematical modelling and brain dynamical networks.
Degree: PhD, 2020, University of Essex
URL: http://repository.essex.ac.uk/28016/
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810294
► In this thesis, we study the dynamics of the Hindmarsh-Rose (HR) model which studies the spike-bursting behaviour of the membrane potential of a single neuron.…
(more)
▼ In this thesis, we study the dynamics of the Hindmarsh-Rose (HR) model which studies the spike-bursting behaviour of the membrane potential of a single neuron. We study the stability of the HR system and compute its Lyapunov exponents (LEs). We consider coupled general sections of the HR system to create an undirected brain dynamical network (BDN) of Nn neurons. Then, we study the concepts of upper bound of mutual information rate (MIR) and synchronisation measure and their dependence on the values of electrical and chemical couplings. We analyse the dynamics of neurons in various regions of parameter space plots for two elementary examples of 3 neurons with two different types of electrical and chemical couplings. We plot the upper bound Ic and the order parameter rho (the measure of synchronisation) and the two largest Lyapunov exponents LE1 and LE2 versus the chemical coupling gn and electrical coupling gl. We show that, even for small number of neurons, the dynamics of the system depends on the number of neurons and the type of coupling strength between them. Finally, we evolve a network of Hindmarsh-Rose neurons by increasing the entropy of the system. In particular, we choose the Kolmogorov-Sinai entropy: HKS (Pesin identity) as the evolution rule. First, we compute the HKS for a network of 4 HR neurons connected simultaneously by two undirected electrical and two undirected chemical links. We get different entropies with the use of different values for both the chemical and electrical couplings. If the entropy of the system is positive, the dynamics of the system is chaotic and if it is close to zero, the trajectory of the system converges to one of the fixed points and loses energy. Then, we evolve a network of 6 clusters of 10 neurons each. Neurons in each cluster are connected only by electrical links and their connections form small-world networks. The six clusters connect to each other only by chemical links. We compare between the combined effect of chemical and electrical couplings with the two concepts, the information flow capacity Ic and HKS in evolving the BDNs and show results that the brain networks might evolve based on the principle of the maximisation of their entropies.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Alwiya, A. (2020). Mathematical modelling and brain dynamical networks. (Doctoral Dissertation). University of Essex. Retrieved from http://repository.essex.ac.uk/28016/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810294
Chicago Manual of Style (16th Edition):
Alwiya, Awatf. “Mathematical modelling and brain dynamical networks.” 2020. Doctoral Dissertation, University of Essex. Accessed February 27, 2021.
http://repository.essex.ac.uk/28016/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810294.
MLA Handbook (7th Edition):
Alwiya, Awatf. “Mathematical modelling and brain dynamical networks.” 2020. Web. 27 Feb 2021.
Vancouver:
Alwiya A. Mathematical modelling and brain dynamical networks. [Internet] [Doctoral dissertation]. University of Essex; 2020. [cited 2021 Feb 27].
Available from: http://repository.essex.ac.uk/28016/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810294.
Council of Science Editors:
Alwiya A. Mathematical modelling and brain dynamical networks. [Doctoral Dissertation]. University of Essex; 2020. Available from: http://repository.essex.ac.uk/28016/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810294
Cardiff University
9.
Tuson, Mark.
Understanding the impact of social networks on the spread of obesity.
Degree: PhD, 2019, Cardiff University
URL: http://orca.cf.ac.uk/128597/
► The spread of obesity through social networks has been well documented most notably by Christakis and Fowler in 2007. In this research we sought to…
(more)
▼ The spread of obesity through social networks has been well documented most notably by Christakis and Fowler in 2007. In this research we sought to understand the nature of the interaction between social networks, the spread of
obesity and the behaviours that drive it. We applied this knowledge in a case study, seeking to evaluate the impact of these effects on different sub-groups of the population.
These objectives were addressed in a hybrid systems modelling approach implemented in a hybrid simulation. An agent based model simulated the social
network and embedded inside each agent was a system dynamics model replicating individual behaviour. The model was parameterised using a stochastic approximation algorithm. This approach allowed us to explore a range of scenarios and also evaluate the topology of the network generated by those scenarios.
The model allowed us to forecast BMI (Body Mass Index) issues for different
age-groups and genders. We were also able to infer the network topography and its effects. We found that for the youngest population sub-groups the network magnified the impact of external factors on the individuals weight, conversely for the other sub groups it acted to reduce that impact. The magnitude of the network effect was inversely correlated with age.
Subjects/Keywords: QA Mathematics
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Manager
APA (6th Edition):
Tuson, M. (2019). Understanding the impact of social networks on the spread of obesity. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/128597/
Chicago Manual of Style (16th Edition):
Tuson, Mark. “Understanding the impact of social networks on the spread of obesity.” 2019. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/128597/.
MLA Handbook (7th Edition):
Tuson, Mark. “Understanding the impact of social networks on the spread of obesity.” 2019. Web. 27 Feb 2021.
Vancouver:
Tuson M. Understanding the impact of social networks on the spread of obesity. [Internet] [Doctoral dissertation]. Cardiff University; 2019. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/128597/.
Council of Science Editors:
Tuson M. Understanding the impact of social networks on the spread of obesity. [Doctoral Dissertation]. Cardiff University; 2019. Available from: http://orca.cf.ac.uk/128597/
University of Glasgow
10.
Waite, Daniel.
Three-strand pretzel knots, knot Floer homology and concordance invariants.
Degree: PhD, 2020, University of Glasgow
URL: http://theses.gla.ac.uk/81472/
► This thesis is concerned with determining the knot Floer homology and concordance invariants of pretzel knots, in particular three-strand pretzel knots. Knot Floer homology is…
(more)
▼ This thesis is concerned with determining the knot Floer homology and concordance invariants of pretzel knots, in particular three-strand pretzel knots. Knot Floer homology is a package of knot invariants developed by Ozsvath and Szabo, and despite the invariants being known for simple classes of knots – for example quasi-alternating, two-bridge and L-space knots – there are still many simple families for which knot Floer homology and the associated concordance invariants are not known.
Recent work by Ozsvath-Szabo developed a construction of an algebraic invariant C(D), conjectured by them to be equal to a variant of knot Floer homology. This complex is a bigraded, bifiltered chain complex whose filtered chain homotopy type is an invariant of a knot. Their construction – which has also been implemented in a C++ program – is a divide and conquer method which decomposes knot diagrams in a certain form into smaller pieces, to which algebraic objects are then associated. These algebraic objects are themselves invariants (up to appropriate equivalence) of partial knot diagrams, and are pieced together to form the full invariant. As with classical knot Floer homology, one can study the homology of this complex C(D), or the homology of subcomplexes and quotient complexes, which are also invariants of a knot.
Even more recent work of Ozsvath and Szabo confirms that this conjectured equivalence between the theories holds. Hence, like the well-known grid homology of a knot, this algebraic method provides a combinatorial construction of knot Floer homology – or in this case some slightly modified version of classical knot Floer homology, like that presented by Dai-Hom-Stroffregen-Truong. The benefit of such combinatorial constructions is that they do not rely on computation of the counts of pseudo-holomorphic representatives of Whitney disks in some high-dimensional space, unlike classical knot Floer homology.
The grid homology developed by Manolescu-Ozsvath-Sarkar has the disadvantage that although one need not calculate these counts – since by construction all Whitney disks considered in this theory have a single pseudo-holomorphic representative – this is at the expense of computing the homology of chain complexes with a very large number of generators (relative to crossing number).
However, the algebraic invariant C(D) of Ozsvath and Szabo has the form of a chain complex whose generators are in one-to-one correspondence with the Kauffman states of a knot diagram. Kauffman states are decorated, oriented knot projections, and the bigrading of the corresponding generators can be determined from the Kauffman states. Similarly, classical knot Floer homology can also be calculated from a chain complex generated by Kauffman states.
Adapting the work of Eftekhary, the Kauffman states for a three-strand pretzel knot P can be placed into three families, based upon the positions of the decorations on each of the three strands. These families have grading information that is determined by the positions of…
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Waite, D. (2020). Three-strand pretzel knots, knot Floer homology and concordance invariants. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/81472/
Chicago Manual of Style (16th Edition):
Waite, Daniel. “Three-strand pretzel knots, knot Floer homology and concordance invariants.” 2020. Doctoral Dissertation, University of Glasgow. Accessed February 27, 2021.
http://theses.gla.ac.uk/81472/.
MLA Handbook (7th Edition):
Waite, Daniel. “Three-strand pretzel knots, knot Floer homology and concordance invariants.” 2020. Web. 27 Feb 2021.
Vancouver:
Waite D. Three-strand pretzel knots, knot Floer homology and concordance invariants. [Internet] [Doctoral dissertation]. University of Glasgow; 2020. [cited 2021 Feb 27].
Available from: http://theses.gla.ac.uk/81472/.
Council of Science Editors:
Waite D. Three-strand pretzel knots, knot Floer homology and concordance invariants. [Doctoral Dissertation]. University of Glasgow; 2020. Available from: http://theses.gla.ac.uk/81472/
University of Glasgow
11.
Jeffreys, Luke.
Single-cylinder square-tiled surfaces: Constructions and applications.
Degree: PhD, 2020, University of Glasgow
URL: http://theses.gla.ac.uk/81526/
► This thesis investigates the combinatorial properties of square-tiled surfaces and studies the connections of these surfaces to the constructions of pseudo-Anosov homeomorphisms, and filling curves…
(more)
▼ This thesis investigates the combinatorial properties of square-tiled surfaces and studies the connections of these surfaces to the constructions of pseudo-Anosov homeomorphisms, and filling curves on punctured surfaces.
We begin by constructing, in every connected component of every stratum of the moduli space of Abelian differentials, square-tiled surfaces having a single vertical and single horizontal cylinder. We show that, for all but the hyperelliptic components, this can be achieved in the minimum number of squares required for a square-tiled surface in the ambient stratum. Moreover, for the hyperelliptic components, we show that the number of squares required is strictly greater and construct surfaces realising these bounds.
Using these surfaces, we demonstrate that pseudo-Anosov homeomorphisms optimising the ratio of Teichmüller to curve graph translation length are, in a reasonable sense, ubiquitous in the connected components of strata of Abelian differentials.
We consider the construction of filling pairs on punctured surfaces. We begin by determining the minimal intersection number of a filling pair on a genus two surface with an odd number, at least three, of punctures completing the work of Aougab-Huang and Aougab-Taylor. We then present a further application of the single-cylinder square-tiled surfaces constructed above by constructing filling pairs on punctured surfaces whose algebraic and geometric intersection numbers are equal.
Finally, we extend the constructions of single-cylinder square-tiled surfaces to certain strata of the moduli space of quadratic differentials.
In Chapter 1, we give the necessary background to describe the main results of this thesis. In Chapter 2, we prove the lemmas that are necessary for the construction of single-cylinder square-tiled surfaces in Chapter 3. Chapter 4 contains the construction of ratio-optimising pseudo-Anosov homeomorphisms, and the constructions of filling pairs on punctured surfaces are given in Chapter 5. In Chapter 6, we extend the constructions of Chapter 3 to certain strata of quadratic differentials. Finally, in Chapter 7, we present some remaining open questions and possible directions for future research. Appendix A gives an alternative proof of Proposition 3.2, and Appendix B contains the python code that realises the construction of Chapter 3.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Jeffreys, L. (2020). Single-cylinder square-tiled surfaces: Constructions and applications. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/81526/
Chicago Manual of Style (16th Edition):
Jeffreys, Luke. “Single-cylinder square-tiled surfaces: Constructions and applications.” 2020. Doctoral Dissertation, University of Glasgow. Accessed February 27, 2021.
http://theses.gla.ac.uk/81526/.
MLA Handbook (7th Edition):
Jeffreys, Luke. “Single-cylinder square-tiled surfaces: Constructions and applications.” 2020. Web. 27 Feb 2021.
Vancouver:
Jeffreys L. Single-cylinder square-tiled surfaces: Constructions and applications. [Internet] [Doctoral dissertation]. University of Glasgow; 2020. [cited 2021 Feb 27].
Available from: http://theses.gla.ac.uk/81526/.
Council of Science Editors:
Jeffreys L. Single-cylinder square-tiled surfaces: Constructions and applications. [Doctoral Dissertation]. University of Glasgow; 2020. Available from: http://theses.gla.ac.uk/81526/
University of Glasgow
12.
King, David James.
Controlled release of therapeutics from orthopaedic implants.
Degree: PhD, 2020, University of Glasgow
URL: http://theses.gla.ac.uk/81530/
► The scientific literature contains a variety of experimental studies centred on the theme of drug delivery from orthopaedic implants (OIs). These experiments cover a wide…
(more)
▼ The scientific literature contains a variety of experimental studies centred on the theme of drug delivery from orthopaedic implants (OIs). These experiments cover a wide range of ideas, including the design of novel implant coatings to contain and control drug release; fabrication and testing of prototype drug-filled devices and; preliminary investigations into the effect of the drug when released into the biological environment. There are a multitude of issues that arise from the use of OIs and of these, the problem of orthopaedic associated infection receives particular attention. A key challenge is the prevention of bacterial infection in order to avoid the failure of the associated implant-a serious complication for patients and a significant burden on health care provider resources. A mathematical study is presented in this thesis which covers a wide variety of topics: ranging from a more fundamental investigation into the use of porosity to control the delivery of drug through to more practical modelling of two seemingly similar prototype orthopaedic fixation pins that have vastly different drug release properties. A common theme is the consideration of how experimental conditions shape the outcome of the experiment and indeed the mathematical model adopted. In order to be able to effectively control the release of drug from an orthopaedic implant, one has to have sufficient knowledge of the purpose of the drug: this determines the required dose and release rate. Thus, towards the end of the thesis, a gradual investigation of the growth of bacteria subject to antibiotic release from the aforementioned pins is carried out, to model the interplay between the two processes.
There are several conclusions that arise from the research contained within this thesis. These include: there exists little-to-no mathematical modelling in the field of drug release from OIs; porosity is likely a very fruitful approach to control the release of a drug from an OI; the conditions in which an experiment is carried out is crucial; the dissolving process of a drug is an important process and one that may be the governing means of limiting the rate of drug release; the use of 1D modelling is sometimes sufficient to answer key questions; there is a need for collaborative efforts between mathematicians and experimentalists for the goal of effective drug-releasing OIs to be realised and; the desired outcome, where infection is concerned, is highly dependent on the drug release profile and, critically, the implant surface concentration of, and potency of, the antibiotic delivered.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
King, D. J. (2020). Controlled release of therapeutics from orthopaedic implants. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/81530/
Chicago Manual of Style (16th Edition):
King, David James. “Controlled release of therapeutics from orthopaedic implants.” 2020. Doctoral Dissertation, University of Glasgow. Accessed February 27, 2021.
http://theses.gla.ac.uk/81530/.
MLA Handbook (7th Edition):
King, David James. “Controlled release of therapeutics from orthopaedic implants.” 2020. Web. 27 Feb 2021.
Vancouver:
King DJ. Controlled release of therapeutics from orthopaedic implants. [Internet] [Doctoral dissertation]. University of Glasgow; 2020. [cited 2021 Feb 27].
Available from: http://theses.gla.ac.uk/81530/.
Council of Science Editors:
King DJ. Controlled release of therapeutics from orthopaedic implants. [Doctoral Dissertation]. University of Glasgow; 2020. Available from: http://theses.gla.ac.uk/81530/
University of Glasgow
13.
Orlendo, Cameline Nafula.
Evolution of lamb immune phenotype in response to nematode infections.
Degree: PhD, 2019, University of Glasgow
URL: http://theses.gla.ac.uk/73024/
► There is considerable variation in the distribution of the number of parasites amongst a flock of lambs infected with gastrointestinal nematodes. One hypothesis that could…
(more)
▼ There is considerable variation in the distribution of the number of parasites amongst a flock of lambs infected with gastrointestinal nematodes. One hypothesis that could explain the observed heterogeneity is that hosts evolve immune phenotypes of varying strengths when infected. The acquired immune response that is mounted by infected lambs is composed of two components. The IgE immune component which regulates parasite numbers within a host, and the IgA immune component which lowers adult parasite fecundity rates, hence decreasing the number of infective agents that are released by the host back into the communal pasture area. In this study, we use adaptive dynamics to study the evolution of the IgE and IgA immune phenotypes, and we use lamb weight as a measure of host fitness. We found that processes affecting the evolution of the lamb immune phenotypes are: the assumed trade-off relationship between the IgE and IgA immune responses, variation in immune costs, the sensitivity of host maintenance efficiency to the presence of adult nematodes and seasonality. A key finding is that we can obtain a dimorphic population that emulates field studies when the presence of adult nematodes severely reduces hosts maintenance efficiency, and the IgE cost is low while the IgA cost is high. Overall, this study provides insight into the processes that could lead to variation in immune phenotypes of lambs infected with nematode parasites.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Orlendo, C. N. (2019). Evolution of lamb immune phenotype in response to nematode infections. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/73024/
Chicago Manual of Style (16th Edition):
Orlendo, Cameline Nafula. “Evolution of lamb immune phenotype in response to nematode infections.” 2019. Doctoral Dissertation, University of Glasgow. Accessed February 27, 2021.
http://theses.gla.ac.uk/73024/.
MLA Handbook (7th Edition):
Orlendo, Cameline Nafula. “Evolution of lamb immune phenotype in response to nematode infections.” 2019. Web. 27 Feb 2021.
Vancouver:
Orlendo CN. Evolution of lamb immune phenotype in response to nematode infections. [Internet] [Doctoral dissertation]. University of Glasgow; 2019. [cited 2021 Feb 27].
Available from: http://theses.gla.ac.uk/73024/.
Council of Science Editors:
Orlendo CN. Evolution of lamb immune phenotype in response to nematode infections. [Doctoral Dissertation]. University of Glasgow; 2019. Available from: http://theses.gla.ac.uk/73024/
The London School of Economics and Political Science (LSE)
14.
Wittur, Nicola.
Optimal use of communication resources with Markovian Payoff functions.
Degree: phd, 2018, The London School of Economics and Political Science (LSE)
URL: http://etheses.lse.ac.uk/3871/
► Our work is based on the model proposed in the paper “Optimal Use of Communication Resources” by Olivier Gossner, Penelope Hernandez and Abraham Neyman, [6].…
(more)
▼ Our work is based on the model proposed in the paper “Optimal Use of Communication Resources” by Olivier Gossner, Penelope Hernandez and Abraham Neyman, [6]. We propose two models that consider an alteration of the payoff function in [6]. The general setup is as follows. A repeated game is played between a team of two players, consisting of a forecaster and an agent, and nature. We assume that the forecaster and the agent share the same payoff function. The forecaster, contrary to the agent, is able to observe future states of nature that have an impact on the team’s payoff. A given pair of strategies for the players induces a sequence of actions and thus implements an average distribution on the actions of interest, i.e., on those actions that determine the payoff. We let the team’s stage payoff not only depend on actions played in one stage, but on actions played in two consecutive stages. We introduce two models that vary w.r.t. the specification of the payoff function and the actions played by nature, with the aim of characterizing the implementable average distributions. This characterization is achieved through an information inequality based on the entropy function, called the information constraint. It expresses a key feature of the strategies of the players, namely the fact that the information used by the agent cannot exceed the amount of information sent by the forecaster. In each model we develop an information constraint that characterizes the implementable distributions as follows. On the one hand, we show that every implementable distribution fulfills the information constraint. And on the other hand, we prove that a certain set of distributions that fulfill the designated information constraint is implementable.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Wittur, N. (2018). Optimal use of communication resources with Markovian Payoff functions. (Doctoral Dissertation). The London School of Economics and Political Science (LSE). Retrieved from http://etheses.lse.ac.uk/3871/
Chicago Manual of Style (16th Edition):
Wittur, Nicola. “Optimal use of communication resources with Markovian Payoff functions.” 2018. Doctoral Dissertation, The London School of Economics and Political Science (LSE). Accessed February 27, 2021.
http://etheses.lse.ac.uk/3871/.
MLA Handbook (7th Edition):
Wittur, Nicola. “Optimal use of communication resources with Markovian Payoff functions.” 2018. Web. 27 Feb 2021.
Vancouver:
Wittur N. Optimal use of communication resources with Markovian Payoff functions. [Internet] [Doctoral dissertation]. The London School of Economics and Political Science (LSE); 2018. [cited 2021 Feb 27].
Available from: http://etheses.lse.ac.uk/3871/.
Council of Science Editors:
Wittur N. Optimal use of communication resources with Markovian Payoff functions. [Doctoral Dissertation]. The London School of Economics and Political Science (LSE); 2018. Available from: http://etheses.lse.ac.uk/3871/
The London School of Economics and Political Science (LSE)
15.
Qu, Yan.
Simulations on Lévy subordinators and Lévy driven contagion models.
Degree: phd, 2019, The London School of Economics and Political Science (LSE)
URL: http://etheses.lse.ac.uk/3947/
► Lévy subordinators have become a fundamental component to be used to construct many useful stochastic processes, which have numerous applications in finance, insurance and many…
(more)
▼ Lévy subordinators have become a fundamental component to be used to construct many useful stochastic processes, which have numerous applications in finance, insurance and many other fields. However, as many applications of Lévy based stochastic models use fairly complicated analytical and probabilistic tools, it has been challenging to implement in practice. Hence, simulation-based study becomes more desirable. In this thesis, we deal with exact simulation on Lévy subordinators and Lévy driven stochastic models. In the first part, we focus on developing more efficient exact simulation schemes for Lévy subordinators with existing simulation algorithms in the literature. Besides, we also introduce a new type of Lévy subordinators, i.e. truncated Lévy subordinators. We study the path properties, develop exact simulation algorithms based on marked renewal representations, and provide relevant applications in finance and insurance. The associated results in this part are later used in the sequel. The second part of this thesis proposes a new type of point processes by generalising the classical self-exciting Hawkes processes and doubly stochastic Poisson processes with Lévy driven Ornstein-Uhlenbeck type intensities. These resulting models are analytically tractable, and intrinsically inherit the great flexibility as well as desirable features from the two original processes, including skewness, leptokurtosis, mean-reverting dynamics, and more importantly, the contagion or feedback effects. These newly constructed processes would then substantially enrich continuous-time models tailored for quantifying the contagion of event arrivals in finance, economics, insurance, queueing and many other fields. In turn, we characterise the distributional properties of this new class of point processes and design an exact simulation algorithm to generate sample paths. This is done by applying the exact distributional decomposition technique. We carry out extensive numerical implementations and tests to demonstrate the accuracy and effectiveness of our scheme and give examples of some financial applications to credit portfolio risk to show the applicability and flexibility of our new model.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
Qu, Y. (2019). Simulations on Lévy subordinators and Lévy driven contagion models. (Doctoral Dissertation). The London School of Economics and Political Science (LSE). Retrieved from http://etheses.lse.ac.uk/3947/
Chicago Manual of Style (16th Edition):
Qu, Yan. “Simulations on Lévy subordinators and Lévy driven contagion models.” 2019. Doctoral Dissertation, The London School of Economics and Political Science (LSE). Accessed February 27, 2021.
http://etheses.lse.ac.uk/3947/.
MLA Handbook (7th Edition):
Qu, Yan. “Simulations on Lévy subordinators and Lévy driven contagion models.” 2019. Web. 27 Feb 2021.
Vancouver:
Qu Y. Simulations on Lévy subordinators and Lévy driven contagion models. [Internet] [Doctoral dissertation]. The London School of Economics and Political Science (LSE); 2019. [cited 2021 Feb 27].
Available from: http://etheses.lse.ac.uk/3947/.
Council of Science Editors:
Qu Y. Simulations on Lévy subordinators and Lévy driven contagion models. [Doctoral Dissertation]. The London School of Economics and Political Science (LSE); 2019. Available from: http://etheses.lse.ac.uk/3947/
The London School of Economics and Political Science (LSE)
16.
Maeng, Hyeyoung.
Adaptive multiscale approaches to regression and trend
segmentation.
Degree: phd, 2019, The London School of Economics and Political Science (LSE)
URL: http://etheses.lse.ac.uk/4025/
► Data-adaptive modelling has enjoyed increasing popularity across a wide range of statistical problems. This thesis studies three adaptive multiscale approaches, one in regression and two…
(more)
▼ Data-adaptive modelling has enjoyed increasing popularity across a wide range of statistical problems. This thesis studies three adaptive multiscale approaches, one in regression and two in trend segmentation. We first introduce a way of modelling temporal dependence in random functions, assuming that those random curves are discretised on an equispaced grid. Considering a common dependence structure across the discretised curves, we predict the most recent point from the past observations in the framework of linear regression. Our model partitions the regression parameters into a smooth and a rough regime where rough regression parameters are used for observations located close to the response variable while the set of regression coefficients for the predictors positioned far from the response variable are assumed to be sampled from a smooth function. The smoothness change-point and the regression parameters are jointly estimated, and the asymptotic behaviour of the estimated change-point is presented. The performance of our new model is illustrated through simulations and four real data examples including country fertility data, pollution data, stock volatility series and sunspot number data. Secondly, we study the detection of multiple change-points corresponding to linear trend changes or point anomalies in one-dimensional data. We propose a data-adaptive multiscale decomposition of the data through an unbalanced wavelet transform, hoping that the sparse representation of the data is achieved through this decomposition. The entire procedure consists of four steps and we provide a precise recipe of each.
Subjects/Keywords: QA Mathematics
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APA ·
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APA (6th Edition):
Maeng, H. (2019). Adaptive multiscale approaches to regression and trend
segmentation. (Doctoral Dissertation). The London School of Economics and Political Science (LSE). Retrieved from http://etheses.lse.ac.uk/4025/
Chicago Manual of Style (16th Edition):
Maeng, Hyeyoung. “Adaptive multiscale approaches to regression and trend
segmentation.” 2019. Doctoral Dissertation, The London School of Economics and Political Science (LSE). Accessed February 27, 2021.
http://etheses.lse.ac.uk/4025/.
MLA Handbook (7th Edition):
Maeng, Hyeyoung. “Adaptive multiscale approaches to regression and trend
segmentation.” 2019. Web. 27 Feb 2021.
Vancouver:
Maeng H. Adaptive multiscale approaches to regression and trend
segmentation. [Internet] [Doctoral dissertation]. The London School of Economics and Political Science (LSE); 2019. [cited 2021 Feb 27].
Available from: http://etheses.lse.ac.uk/4025/.
Council of Science Editors:
Maeng H. Adaptive multiscale approaches to regression and trend
segmentation. [Doctoral Dissertation]. The London School of Economics and Political Science (LSE); 2019. Available from: http://etheses.lse.ac.uk/4025/
The London School of Economics and Political Science (LSE)
17.
Park, Sujin.
Consistent estimator of ex-post covariation of discretely observed diffusion processes and its application to high frequency financial time series.
Degree: phd, 2011, The London School of Economics and Political Science (LSE)
URL: http://etheses.lse.ac.uk/182/
► First chapter of my thesis reviews recent developments in the theory and practice of volatility measurement. We review the basic theoretical framework and describe the…
(more)
▼ First chapter of my thesis reviews recent developments in the theory and practice of
volatility measurement. We review the basic theoretical framework and describe the
main approaches to volatility measurement in continuous time. In this literature the
central parameter of interest is the integrated variance and its multivariate counterpart. We describe the measurement of these parameters under ideal circumstances
and when the data are subject to measurement error, microstructure issues. We also
describe some common applications of this literature.
In the second chapter, we propose a new estimator of multivariate ex-post volatility that is robust to microstructure noise and asynchronous data timing. The method
is based on Fourier domain techniques. The advantage of this method is that it does
not require an explicit time alignment, unlike existing methods in the literature. We
derive the large sample properties of our estimator under general assumptions allowing for the number of sample points for different assets to be of different order of
magnitude. We show in extensive simulations that our method outperforms the time
domain estimator especially when two assets are traded very asynchronously and with
different liquidity.
In the third chapter, we propose to model high frequency price series by a timedeformed L´evy process. The deformation function is modeled by a piecewise linear
function of a physical time with a slope depending on the marks associated with
intra-day transaction data. The performance of a quasi-MLE and an estimator based
on a permutation-like statistic is examined in extensive simulations. We also consider
estimating the deformation function nonparametrically by pulling together many time
series. We show that financial returns spaced by equal elapse of estimated deformed time are homogenous. We propose an order execution strategy using the fitted deformation time
Subjects/Keywords: QA Mathematics
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APA ·
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Export
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Manager
APA (6th Edition):
Park, S. (2011). Consistent estimator of ex-post covariation of discretely observed diffusion processes and its application to high frequency financial time series. (Doctoral Dissertation). The London School of Economics and Political Science (LSE). Retrieved from http://etheses.lse.ac.uk/182/
Chicago Manual of Style (16th Edition):
Park, Sujin. “Consistent estimator of ex-post covariation of discretely observed diffusion processes and its application to high frequency financial time series.” 2011. Doctoral Dissertation, The London School of Economics and Political Science (LSE). Accessed February 27, 2021.
http://etheses.lse.ac.uk/182/.
MLA Handbook (7th Edition):
Park, Sujin. “Consistent estimator of ex-post covariation of discretely observed diffusion processes and its application to high frequency financial time series.” 2011. Web. 27 Feb 2021.
Vancouver:
Park S. Consistent estimator of ex-post covariation of discretely observed diffusion processes and its application to high frequency financial time series. [Internet] [Doctoral dissertation]. The London School of Economics and Political Science (LSE); 2011. [cited 2021 Feb 27].
Available from: http://etheses.lse.ac.uk/182/.
Council of Science Editors:
Park S. Consistent estimator of ex-post covariation of discretely observed diffusion processes and its application to high frequency financial time series. [Doctoral Dissertation]. The London School of Economics and Political Science (LSE); 2011. Available from: http://etheses.lse.ac.uk/182/
Cardiff University
18.
Williams, Isabelle.
Machine learning algorithms for crime prevention and predictive policing.
Degree: PhD, 2018, Cardiff University
URL: http://orca.cf.ac.uk/123787/
► Recent developments within the field of Machine Learning have given rise to the possibility of deploying these algorithms within a live policing environment. This thesis,…
(more)
▼ Recent developments within the field of Machine Learning have given rise to the possibility of deploying these algorithms within a live policing environment. This thesis, motivated by the needs of Dyfed-Powys Police, focuses on developing a series of predictive tools that can be used directly within a live setting in order to improve efficiency across the force. With an area of coverage that spans four socioeconomically diverse yet sparsely populated counties, Dyfed-Powys Police face a unique set of challenges in managing an increasingly limited set of resources such that offenders can be properly managed. The issue of personnel management is first addressed in the construction of a recommender system, which investigates the use of clustering techniques to exploit a stable pattern in the times at which crimes occur in various locations across the region. This is then followed with the development of a Recurrent Neural Network, which aims to predict the time to next offence within a particular narrowly-defined partition of the area.
By developing a series of tools that make use of existing data to predict which offenders within their database are most likely to reoffend, we aim to assist Dyfed-Powys in monitoring and preventing recidivism across the area. Firstly, we investigate the use of Random Forests and XGBoost algorithms, as well as Feedforward Neural Networks to predict an offender's likelihood of reoffence from a series of diverse factors. Secondly, we develop the aforementioned Random Forests algorithm into a survival model that aims to predict an offender's time to reoffence. Lastly, we develop a stacked model, which uses publicly available data to construct an Area Classifcation score for use as a factor within the original reoffence classification model. Insightful results are obtained, indicating a clear case for the use of many of these techniques in a live setting.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Williams, I. (2018). Machine learning algorithms for crime prevention and predictive policing. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/123787/
Chicago Manual of Style (16th Edition):
Williams, Isabelle. “Machine learning algorithms for crime prevention and predictive policing.” 2018. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/123787/.
MLA Handbook (7th Edition):
Williams, Isabelle. “Machine learning algorithms for crime prevention and predictive policing.” 2018. Web. 27 Feb 2021.
Vancouver:
Williams I. Machine learning algorithms for crime prevention and predictive policing. [Internet] [Doctoral dissertation]. Cardiff University; 2018. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/123787/.
Council of Science Editors:
Williams I. Machine learning algorithms for crime prevention and predictive policing. [Doctoral Dissertation]. Cardiff University; 2018. Available from: http://orca.cf.ac.uk/123787/
University of Glasgow
19.
Ismaeel, Ahmed Mostafa Abdelhady.
A mathematical model for photothermal therapy of spherical tumors.
Degree: PhD, 2020, University of Glasgow
URL: http://theses.gla.ac.uk/80268/
► Photothermal ablation is a promising new technique for treatment of some cancers, where metal nanoparticles are introduced into the tumor and the system is locally…
(more)
▼ Photothermal ablation is a promising new technique for treatment of some cancers, where metal nanoparticles are introduced into the tumor and the system is locally heated with a laser to destroy the malignant cells. The aim is to have nanoparticles accumulate within the tumor and not in the surrounding healthy tissue, so that the heat source leads to a differential increase in temperature in the cancer and hence cell death.
We begin by examining nanoparticle delivery from a single blood vessel into surrounding tissue using asymptotic analysis to construct the extravasation flux of nanoparticles into the tissue.
We then incorporate this flux into a spatially one dimensional model which includes interstitial fluid flow to examine the distribution of nanoparticles across the tumor and the surrounding tissue. In this model we also consider nanoparticles conjugated with ligands which selectively bind to tumor cell surface receptors and eventually leads to nanoparticle internalization within the cell. We study how the mass of accumulated nanoparticles within the tumour (and the surrounding tissue) is influenced by the nanoparticle delivery time interval, ligand nanoparticle conjugation and tumor cell capacity for internalized nanoparticles.
We then mimic laser irradiation of the tumor and the surrounding tissue (which comprise nanoparticles) estimating the temperature elevation and the induced tissue damage within the tissue. Finally, we validate our predictions against two different sets of experimental data and then discuss how to optimize the outputs of the photothermal therapy. We show that conjugating binding ligands to the nanoparticles can lead to a heterogeneous spatial distribution of nanoparticles and reduce tumor damage induced by laser irradiation. We conclude by discussing strategies to optimize the treatment protocol to induce maximal tumor damage with minimal side effects in the surrounding healthy tissue.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Ismaeel, A. M. A. (2020). A mathematical model for photothermal therapy of spherical tumors. (Doctoral Dissertation). University of Glasgow. Retrieved from http://theses.gla.ac.uk/80268/
Chicago Manual of Style (16th Edition):
Ismaeel, Ahmed Mostafa Abdelhady. “A mathematical model for photothermal therapy of spherical tumors.” 2020. Doctoral Dissertation, University of Glasgow. Accessed February 27, 2021.
http://theses.gla.ac.uk/80268/.
MLA Handbook (7th Edition):
Ismaeel, Ahmed Mostafa Abdelhady. “A mathematical model for photothermal therapy of spherical tumors.” 2020. Web. 27 Feb 2021.
Vancouver:
Ismaeel AMA. A mathematical model for photothermal therapy of spherical tumors. [Internet] [Doctoral dissertation]. University of Glasgow; 2020. [cited 2021 Feb 27].
Available from: http://theses.gla.ac.uk/80268/.
Council of Science Editors:
Ismaeel AMA. A mathematical model for photothermal therapy of spherical tumors. [Doctoral Dissertation]. University of Glasgow; 2020. Available from: http://theses.gla.ac.uk/80268/
Cardiff University
20.
Olbermann, Heiner.
Quantum field theory via vertex algebras.
Degree: PhD, 2010, Cardiff University
URL: http://orca.cf.ac.uk/54994/
► We investigate an alternative formulation of quantum field theory that elevates the Wilson- Zimmermann operator product expansion (OPE) to an axiom of the theory. We…
(more)
▼ We investigate an alternative formulation of quantum field theory that elevates the Wilson- Zimmermann operator product expansion (OPE) to an axiom of the theory. We observe that the information contained in the OPE coefficients may be straightforwardly repackaged into "vertex operators". This way of formulating quantum field theory has quite obvious similarities to the theory of vertex algebras. As examples of this framework, we discuss the free massless boson in D dimensions and the massless Thirring model. We set up perturbation theory for vertex algebras. We discuss a general theory of perturbations of vertex algebras, which is similar to the Hochschild cohomology describing the deformation theory of ordinary algebras. We pass on to a more explicit discussion by looking at perturbations of the free massless boson in D dimensions. The perturbations we consider correspond to some interaction Lagrangian P(<p) = A Cp if. We construct the perturbations by exploiting the associativity of the vertex operators and the field equation in perturbative form. We develop a set of graphical rules that display the vertex operators as certain multiple series reminiscent of the hypergeometric series.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Olbermann, H. (2010). Quantum field theory via vertex algebras. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/54994/
Chicago Manual of Style (16th Edition):
Olbermann, Heiner. “Quantum field theory via vertex algebras.” 2010. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/54994/.
MLA Handbook (7th Edition):
Olbermann, Heiner. “Quantum field theory via vertex algebras.” 2010. Web. 27 Feb 2021.
Vancouver:
Olbermann H. Quantum field theory via vertex algebras. [Internet] [Doctoral dissertation]. Cardiff University; 2010. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/54994/.
Council of Science Editors:
Olbermann H. Quantum field theory via vertex algebras. [Doctoral Dissertation]. Cardiff University; 2010. Available from: http://orca.cf.ac.uk/54994/
Cardiff University
21.
Leiler, Gregor.
On a derivation of the Boltzmann equation in Quantum Field Theory.
Degree: PhD, 2010, Cardiff University
URL: http://orca.cf.ac.uk/55024/
► The Boltzmann equation (BE) is a commonly used tool for the study of non-equilibrium many particle systems. It has been introduced in 1872 by Ludwig…
(more)
▼ The Boltzmann equation (BE) is a commonly used tool for the study of non-equilibrium many particle systems. It has been introduced in 1872 by Ludwig Boltzmann and has been widely generalized throughout the years. Today it is commonly used in physical applications, from the study of ordinary fluids to problems in particle Cosmology where Quantum Field Theoretical techniques are essential. Despite its numerous experimental successes, the conceptual basis of the BE is not entirely clear. For instance, it is well known that it is not a fundamental equation of physics like, say, the Heisenberg equation (HE). A natural question then arises whether it is possible to derive the BE from physical first principles, i.e. the Heisenberg equation in Quantum Field Theory. In this work we attempted to answer this question and succeeded in deriving the BE from the HE, thus further clarifying its conceptual status. In particular, the results we have obtained are as follows. Firstly, we establish the non-perturbative validity of what we call the "pre-Boltzmann equation". The crucial point here is that this latter equation is equivalent to the Heisenberg equation. Secondly, we proceed to consider various limits of the pre-Boltzmann equation, namly the "low density" and the "weak coupling" limits, to obtain two equations that can be considered as generalizations of the BE. These limits are always taken together with the "long time" limit, which allows us to interpret the BE as an appropriate long time limit of the HE. The generalization we obtain consists in additional "correction" terms to the usual Boltzmann collision factor, and can be associated to multiple particle scattering. Unlike the pre-Boltzmann equation, these latter results are only valid pertubatively. Finally, we briefly consider the possibility to extend these results beyond said limits and outline some important aspects in this case.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Leiler, G. (2010). On a derivation of the Boltzmann equation in Quantum Field Theory. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/55024/
Chicago Manual of Style (16th Edition):
Leiler, Gregor. “On a derivation of the Boltzmann equation in Quantum Field Theory.” 2010. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/55024/.
MLA Handbook (7th Edition):
Leiler, Gregor. “On a derivation of the Boltzmann equation in Quantum Field Theory.” 2010. Web. 27 Feb 2021.
Vancouver:
Leiler G. On a derivation of the Boltzmann equation in Quantum Field Theory. [Internet] [Doctoral dissertation]. Cardiff University; 2010. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/55024/.
Council of Science Editors:
Leiler G. On a derivation of the Boltzmann equation in Quantum Field Theory. [Doctoral Dissertation]. Cardiff University; 2010. Available from: http://orca.cf.ac.uk/55024/
Cardiff University
22.
Taylor, Lisa Ann.
Local search methods for the post enrolment-based course timetabling problem.
Degree: mphil, 2013, Cardiff University
URL: http://orca.cf.ac.uk/58780/
► The work presented in this thesis concerns the problem of post enrolment-based course time-tabling. The motivation for this is the increasing importance of the automation…
(more)
▼ The work presented in this thesis concerns the problem of post enrolment-based course time-tabling. The motivation for this is the increasing importance of the automation of timetabling due to the growth in popularity of Higher Education in recent years. There were 464,910 accepted applicants to universities in the United Kingdom in 2012 which is a 12% rise in five years. This will inevitably lead to an expansion in the number of courses, modules and teachers. As a result, the ability to manually construct timetables has become increasingly impractical.
A two-stage approach is investigated that aims to use heuristic and metaheuristic approaches to obtain a satisfactory timetable that suits the needs of the staff and students at educational institutions. The first stage consists of using selection heuristics to construct an initial solution. Two approaches that then attempt to find feasibility are presented. The first applies a tabu search algorithm with a number of neighbourhood operators that navigate the search space for feasible solutions. The second approach implements a PartialCol algorithm.
The second stage aims to improve the solution quality by minimising the number of soft constraint violations. The feasibility ratio could be an indicator of the connectivity of the search space, so methods of increasing the feasibility ratio are presented. If the feasibility ratio can be increased then the number of soft constraint violations would be expected to decrease.
These techniques were applied to the 24 instances provided for track two of the International Timetabling Competition 2007. The conclusions of the experimentation and investigative processes show that the PartialCol algorithm was more successful, in terms of finding feasible solutions, than the method that employs the neighbourhood operators. However, improvements to the soft constraint penalty were achieved using these neighbourhood operators.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Taylor, L. A. (2013). Local search methods for the post enrolment-based course timetabling problem. (Masters Thesis). Cardiff University. Retrieved from http://orca.cf.ac.uk/58780/
Chicago Manual of Style (16th Edition):
Taylor, Lisa Ann. “Local search methods for the post enrolment-based course timetabling problem.” 2013. Masters Thesis, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/58780/.
MLA Handbook (7th Edition):
Taylor, Lisa Ann. “Local search methods for the post enrolment-based course timetabling problem.” 2013. Web. 27 Feb 2021.
Vancouver:
Taylor LA. Local search methods for the post enrolment-based course timetabling problem. [Internet] [Masters thesis]. Cardiff University; 2013. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/58780/.
Council of Science Editors:
Taylor LA. Local search methods for the post enrolment-based course timetabling problem. [Masters Thesis]. Cardiff University; 2013. Available from: http://orca.cf.ac.uk/58780/
Cardiff University
23.
Kerss, Alexander.
Fractal activity time and integer valued models in finance.
Degree: PhD, 2014, Cardiff University
URL: http://orca.cf.ac.uk/68211/
► The role of the financial mathematician is to find solutions to problems in finance through the application of mathematical theory. The motivation for this work…
(more)
▼ The role of the financial mathematician is to find solutions to problems in finance through the application of mathematical theory. The motivation for this work is specification of models to accurately describe the price evolution of a risky asset, a risky asset is for example a security traded on a financial market such as a stock, currency or benchmark index. This thesis makes contributions in two classes of models, namely activity time models and integer valued models, by the discovery of new real valued and integer valued stochastic processes. In both model frameworks applications to option pricing are considered.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Kerss, A. (2014). Fractal activity time and integer valued models in finance. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/68211/
Chicago Manual of Style (16th Edition):
Kerss, Alexander. “Fractal activity time and integer valued models in finance.” 2014. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/68211/.
MLA Handbook (7th Edition):
Kerss, Alexander. “Fractal activity time and integer valued models in finance.” 2014. Web. 27 Feb 2021.
Vancouver:
Kerss A. Fractal activity time and integer valued models in finance. [Internet] [Doctoral dissertation]. Cardiff University; 2014. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/68211/.
Council of Science Editors:
Kerss A. Fractal activity time and integer valued models in finance. [Doctoral Dissertation]. Cardiff University; 2014. Available from: http://orca.cf.ac.uk/68211/
Cardiff University
24.
Shone, Robert William.
Optimal control of queueing systems with multiple heterogeneous facilities.
Degree: PhD, 2014, Cardiff University
URL: http://orca.cf.ac.uk/71359/
► This thesis discusses queueing systems in which decisions are made when customers arrive, either by individual customers themselves or by a central controller. Decisions are…
(more)
▼ This thesis discusses queueing systems in which decisions are made when customers arrive, either by individual customers themselves or by a central controller. Decisions are made concerning whether or not customers should be admitted to the system (admission control) and, if they are to be admitted, where they should go to receive service (routing control). An important objective is to compare the effects of "selfish" decision-making, in which customers make decisions aimed solely at optimising their own outcomes, with those of "socially optimal" control policies, which optimise the economic performance of the system as a whole. The problems considered are intended to be quite general in nature, and the resulting findings are therefore broad in scope.
Initially, M/M/1 queueing systems are considered, and the results presented establish novel connections between two distinct areas of the literature. Subsequently, a more complicated problem is considered, involving routing control in a system which consists of heterogeneous, multiple-server facilities arranged in parallel. It is shown that the multiple-facility system can be formulated mathematically as a Markov Decision Process (MDP), and this enables a fundamental relationship to be proved between individually optimal and socially optimal policies which is of great theoretical and practical importance. Structural properties of socially optimal policies are analysed rigorously, and it is found that 'simple' characterisations of socially optimal policies are usually unattainable in systems with heterogeneous facilities. Finally, the feasibility of finding 'near-optimal' policies for large scale systems by using heuristics and simulation-based methods is considered.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Shone, R. W. (2014). Optimal control of queueing systems with multiple heterogeneous facilities. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/71359/
Chicago Manual of Style (16th Edition):
Shone, Robert William. “Optimal control of queueing systems with multiple heterogeneous facilities.” 2014. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/71359/.
MLA Handbook (7th Edition):
Shone, Robert William. “Optimal control of queueing systems with multiple heterogeneous facilities.” 2014. Web. 27 Feb 2021.
Vancouver:
Shone RW. Optimal control of queueing systems with multiple heterogeneous facilities. [Internet] [Doctoral dissertation]. Cardiff University; 2014. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/71359/.
Council of Science Editors:
Shone RW. Optimal control of queueing systems with multiple heterogeneous facilities. [Doctoral Dissertation]. Cardiff University; 2014. Available from: http://orca.cf.ac.uk/71359/
Cardiff University
25.
Rowse, Elizabeth Louise.
Robust optimisation of operating theatre schedules.
Degree: PhD, 2015, Cardiff University
URL: http://orca.cf.ac.uk/80684/
► Hospitals in the UK are increasingly having to cancel a large proportion of elective operations due to the unavailability of beds on hospital wards for…
(more)
▼ Hospitals in the UK are increasingly having to cancel a large proportion of elective operations due to the unavailability of beds on hospital wards for post-operative recovery. The availability of post-operative beds is therefore critical to the scheduling of surgical procedures and the throughput of patients in a hospital. The focus of this research is to investigate, via data-driven modelling, systematic reasons for the unavailability of beds and to demonstrate how the Master Surgery Schedule (MSS) can be constructed using Operational Research techniques to minimise the number of cancellations of elective operations.
Statistical analysis of data provided by the University Hospital of Wales, Cardiff was performed, providing information on patient demand and length of stay distributions. A two-stage modelling process was developed to construct and simulate an MSS that minimises the number of cancellations. The first stage involves a novel set partitioning based optimisation model that incorporates operating room and bed constraints. The second stage simulates the resulting optimal schedule to provide measures on how well the schedule would perform if implemented. The results from this two-stage model provide insights into when best to schedule surgical specialties and how best the beds are distributed between wards.
Two optimisation under uncertainty techniques are then employed to incorporate the uncertainty associated with the bed requirements into the optimisation process. A robust optimisation (RO) approach that uses protection functions in each bed constraint is developed. Investigations into varying levels of protection are performed in order to gain insight into the so called `price of robustness'. Results show that MSSs that are constructed from protecting more of the uncertainty result in fewer cancellations and a smaller probability of requiring more beds than are available.
The deterministic optimisation model is then extended to become a scenario-based optimisation model in which more scenarios of bed requirement are incorporated into a single optimisation model. Results show that as more scenarios are included, a more robust schedule is generated and fewer cancellations are expected.
Results from the different approaches are compared to assess the benefits of using RO techniques. Future research directions following from this work are discussed, including the construction of the MSS based on sub-specialties and investigation of different working practices within the case study hospital.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Rowse, E. L. (2015). Robust optimisation of operating theatre schedules. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/80684/
Chicago Manual of Style (16th Edition):
Rowse, Elizabeth Louise. “Robust optimisation of operating theatre schedules.” 2015. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/80684/.
MLA Handbook (7th Edition):
Rowse, Elizabeth Louise. “Robust optimisation of operating theatre schedules.” 2015. Web. 27 Feb 2021.
Vancouver:
Rowse EL. Robust optimisation of operating theatre schedules. [Internet] [Doctoral dissertation]. Cardiff University; 2015. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/80684/.
Council of Science Editors:
Rowse EL. Robust optimisation of operating theatre schedules. [Doctoral Dissertation]. Cardiff University; 2015. Available from: http://orca.cf.ac.uk/80684/
Cardiff University
26.
Alrajhi, Khaled.
Heuristic algorithms for static and dynamic frequency assignment problems.
Degree: PhD, 2016, Cardiff University
URL: http://orca.cf.ac.uk/94194/
► This thesis considers the frequency assignment problem (FAP), which is a real world problem of assigning frequencies to wireless communication connections (also known as requests)…
(more)
▼ This thesis considers the frequency assignment problem (FAP), which is a real world problem of assigning frequencies to wireless communication connections (also known as requests) while satisfying a set of constraints in order to prevent a loss of signal quality. This problem has many different applications such as mobile phones, TV broadcasting, radio and military operations. In this thesis, two variants of the FAP are considered, namely the static and the dynamic FAPs. The static FAP does not change over time, while the dynamic FAP changes over time as new requests gradually be-come known and frequencies need to be assigned to those requests effectively and promptly. The dynamic FAP has received little attention so far in the literature com-pared with the static FAP.
This thesis consists of two parts: the first part discusses and develops three heuristic algorithms, namely tabu search (TS), ant colony optimization (ACO) and hyper heuris-tic (HH), to solve the static FAP. These heuristic algorithms are chosen to represent different characteristics of heuristic algorithms in order to identify an appropriate solu-tion method for this problem. Several novel and existing techniques have been used to improve the performance of these heuristic algorithms. In terms of TS, one of the nov-el techniques aims to determine a lower bound on the number of frequencies that are required from each domain for a feasible solution to exist, based on the underlying graph colouring model. These lower bounds are used to ensure that we never waste time trying to find a feasible solution with a set of frequencies that do not satisfy the lower bounds, since there is no feasible solution in this search area. Another novel technique hybridises TS with multiple neighbourhood structures, one of which is used as a diversification technique. In terms of ACO, the concept of a well-known graph colouring algorithm, namely recursive largest first, is used. Moreover, some of the key factors in producing a high quality ACO implementation are examined such as differ-ent definitions of visibility and trail, and optimization of numerous parameters. In terms of HH, simple and advanced low level heuristics each with an associated inde-pendent tabu list are applied in this study. The lower bound on the number of fre-quencies that are required from each domain for a feasible solution to exist is also used.
Based on the experimental results, it is found that the best performing heuristic algo-rithm is TS, with HH also being competitive, whereas ACO achieves poor perfor-mance. Additionally, TS shows competitive performance compared with other algo-rithms in the literature.
In the second part of this thesis, various approaches are designed to solve the dynamic FAP. The best heuristic algorithms considered in the first part of this thesis are used to construct these approaches. It is interesting to investigate whether heuristic algorithms which work well on the static FAP also prove efficient on the dynamic FAP. Addi-tionally, several techniques are…
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Alrajhi, K. (2016). Heuristic algorithms for static and dynamic frequency assignment problems. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/94194/
Chicago Manual of Style (16th Edition):
Alrajhi, Khaled. “Heuristic algorithms for static and dynamic frequency assignment problems.” 2016. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/94194/.
MLA Handbook (7th Edition):
Alrajhi, Khaled. “Heuristic algorithms for static and dynamic frequency assignment problems.” 2016. Web. 27 Feb 2021.
Vancouver:
Alrajhi K. Heuristic algorithms for static and dynamic frequency assignment problems. [Internet] [Doctoral dissertation]. Cardiff University; 2016. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/94194/.
Council of Science Editors:
Alrajhi K. Heuristic algorithms for static and dynamic frequency assignment problems. [Doctoral Dissertation]. Cardiff University; 2016. Available from: http://orca.cf.ac.uk/94194/
Cardiff University
27.
Moore, Stephen.
Non-semisimple planar algebras from Ūq(sl2).
Degree: PhD, 2016, Cardiff University
URL: http://orca.cf.ac.uk/97662/
► We construct examples of non-semisimple tensor categories using planar algebras, with our main focus being on a construction from the restricted quantum group Ūq(sl_2). We…
(more)
▼ We construct examples of non-semisimple tensor categories using planar algebras, with our main focus being on a construction from the restricted quantum group Ūq(sl_2). We describe the generators and prove a number of relations for the Ūq(sl_2) planar algebra, as well as describing diagrammatically various homomorphisms between modules, and conjecture a formula for projections onto indecomposable modules.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Moore, S. (2016). Non-semisimple planar algebras from Ūq(sl2). (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/97662/
Chicago Manual of Style (16th Edition):
Moore, Stephen. “Non-semisimple planar algebras from Ūq(sl2).” 2016. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/97662/.
MLA Handbook (7th Edition):
Moore, Stephen. “Non-semisimple planar algebras from Ūq(sl2).” 2016. Web. 27 Feb 2021.
Vancouver:
Moore S. Non-semisimple planar algebras from Ūq(sl2). [Internet] [Doctoral dissertation]. Cardiff University; 2016. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/97662/.
Council of Science Editors:
Moore S. Non-semisimple planar algebras from Ūq(sl2). [Doctoral Dissertation]. Cardiff University; 2016. Available from: http://orca.cf.ac.uk/97662/
Cardiff University
28.
Symons, Frederick.
On uniqueness in some physical systems.
Degree: PhD, 2017, Cardiff University
URL: http://orca.cf.ac.uk/103772/
► In this work we present some uniqueness and cloaking results for a related pair of inverse problems. The first concerns recovering the parameter q in…
(more)
▼ In this work we present some uniqueness and cloaking results for a related pair
of inverse problems. The first concerns recovering the parameter q in a Bessel-type
operator pencil, over L2(0, 1; rdr) from (a generalisation of) the Weyl–-Titchmarsh boundary m-function. We assume that both coefficients, w and q, are singular at 0. We prove q is uniquely determined
by the sequence m(-n2) (n = 1, 2, 3, ...), using asymptotic and spectral
analysis and m-function interpolation results. For corollary we find, in a halfdisc
with a singular “Dirichlet-point” boundary condition on the straight edge,
a singular radial Schroedinger potential is uniquely determined by Dirichlet-to-
Neumann boundary measurements on the semi-circular edge.
The second result concerns recovery of three things—a Schroedinger potential
in a planar domain, a Dirichlet-point boundary condition on part of the boundary,
and a self-adjointness-imposing condition—from Dirichlet-to-Neumann measurements
on the remaining boundary. With modern approaches to the inverse conductivity
problem and a solution-space density argument we show the boundary
condition cloaks the potential and vice versa. Appealing to negative eigen-value
asymptotics we find the full-frequency problem has full uniqueness.
Subjects/Keywords: QA Mathematics
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APA (6th Edition):
Symons, F. (2017). On uniqueness in some physical systems. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/103772/
Chicago Manual of Style (16th Edition):
Symons, Frederick. “On uniqueness in some physical systems.” 2017. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/103772/.
MLA Handbook (7th Edition):
Symons, Frederick. “On uniqueness in some physical systems.” 2017. Web. 27 Feb 2021.
Vancouver:
Symons F. On uniqueness in some physical systems. [Internet] [Doctoral dissertation]. Cardiff University; 2017. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/103772/.
Council of Science Editors:
Symons F. On uniqueness in some physical systems. [Doctoral Dissertation]. Cardiff University; 2017. Available from: http://orca.cf.ac.uk/103772/
Cardiff University
29.
Hill, Sally.
Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions.
Degree: PhD, 2018, Cardiff University
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
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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). Cardiff University. 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, Cardiff University. Accessed February 27, 2021.
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. 27 Feb 2021.
Vancouver:
Hill S. Problems related to number theory: Sum-and-distance systems, reversible square matrices and divisor functions. [Internet] [Doctoral dissertation]. Cardiff University; 2018. [cited 2021 Feb 27].
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]. Cardiff University; 2018. Available from: http://orca.cf.ac.uk/111467/
Cardiff University
30.
Phillips, Tomos.
On positive and conditionally negative definite functions with a singularity at zero, and their applications in potential theory.
Degree: PhD, 2018, Cardiff University
URL: http://orca.cf.ac.uk/116960/
► It is widely known that positive and conditionally negative definite functions take finite values at the origin. Nevertheless, there exist functions with a singularity at…
(more)
▼ It is widely known that positive and conditionally negative definite functions take finite values at the origin.
Nevertheless, there exist functions with a singularity at zero, arising naturally e.g. in potential theory or the study of (continuous) extremal measures, which still exhibit the general characteristics of positive or conditional negative definiteness.
Taking a framework set up by Lionel Cooper as a motivation, we study the general properties of functions which are positive definite in an extended sense. We prove a Bochner-type theorem and, as a consequence, show how unbounded positive definite functions arise as limits of classical positive definite functions, as well as that
their space is closed under convolution. Moreover, we provide criteria for a function to be positive definite in the extended sense, showing in particular that complete monotonicity in conjunction with local absolute integrability is sufficient.
The celebrated Schoenberg theorem establishes a relation between positive definite and conditionally negative definite functions. By introducing a notion of conditional negative definiteness which accounts for the classical, non-singular conditionally negative definite functions, as well as functions which are unbounded at the origin, we extend this result to real-valued functions with a singularity at zero. Moreover, we demonstrate how singular conditionally negative definite functions arise as limits of classical conditionally negative definite functions and provide several examples of functions which are unbounded at the origin and conditionally negative definite in an extended sense.
Finally, we study the convexity and minimisation of the energy associated with various singular, completely monotone functions, which have not previously been considered in the field of potential theory or experimental design and solve the corresponding energy problems by means of numerically computing approximations to the (optimal) minimising measures.
Subjects/Keywords: QA Mathematics
Record Details
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Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Phillips, T. (2018). On positive and conditionally negative definite functions with a singularity at zero, and their applications in potential theory. (Doctoral Dissertation). Cardiff University. Retrieved from http://orca.cf.ac.uk/116960/
Chicago Manual of Style (16th Edition):
Phillips, Tomos. “On positive and conditionally negative definite functions with a singularity at zero, and their applications in potential theory.” 2018. Doctoral Dissertation, Cardiff University. Accessed February 27, 2021.
http://orca.cf.ac.uk/116960/.
MLA Handbook (7th Edition):
Phillips, Tomos. “On positive and conditionally negative definite functions with a singularity at zero, and their applications in potential theory.” 2018. Web. 27 Feb 2021.
Vancouver:
Phillips T. On positive and conditionally negative definite functions with a singularity at zero, and their applications in potential theory. [Internet] [Doctoral dissertation]. Cardiff University; 2018. [cited 2021 Feb 27].
Available from: http://orca.cf.ac.uk/116960/.
Council of Science Editors:
Phillips T. On positive and conditionally negative definite functions with a singularity at zero, and their applications in potential theory. [Doctoral Dissertation]. Cardiff University; 2018. Available from: http://orca.cf.ac.uk/116960/
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