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Sets and indices in linear programming modelling and their integration with relational data models

REA Auditado

LP models are usually constructed using index sets and data tables which are closely related to the attributes and relations of relational database (RDB) systems. We extend the syntax of MPL, an existing LP modelling language, in order to connect it to a given RDB system. This approach reuses existing modelling and database software, provides a rich modelling environment and achieves model and data independence. This integrated software enables Mathematical Programming to be widely used as a decision support tool by unlocking the data residing in corporate databases.

Tema: general: 

• Ciencias›Matemáticas

A domain decomposition method for approximating the conformal modules of long quadrilaterals

REA Auditado

This paper is concerned with the study of a domain decomposition method for
approximating the conformal modules of long quadrilaterals. The method has been studied already by us and also by D Gaier and W K Hayman, but only in connection with a special class of quadrilaterals, viz.

Tema: general: 

• Ciencias›Matemáticas

3D packing of balls in different containers by VNS

REA Auditado

In real world applications such as the transporting of goods products, packing is
a major issue. Goods products need to be packed such that the smallest space is
wasted to achieve the maximum transportation efficiency. Packing becomes more challenging and complex when the product is circular/spherical. This thesis focuses
on the best way to pack three-dimensional unit spheres into the smallest spherical and cubical space.

Tema: general: 

• Ciencias›Matemáticas

Adaptive methods for time domain boundary integral equations for acoustic scattering

REA Auditado

This thesis is concerned with the study of transient scattering of acoustic waves by an obstacle in an infinite domain, where the scattered wave is represented in terms of time domain boundary layer potentials. The problem of finding the unknown solution of the scattering problem is thus reduced to the problem of finding the unknown density of the time domain boundary layer operators on the obstacle’s boundary, subject to the boundary data of the known incident wave.

Tema: general: 

• Ciencias›Matemáticas

Enhanced indexation based on second-order stochastic dominance

REA Auditado

Second order Stochastic Dominance (SSD) has a well recognised importance in portfolio selection, since it provides a natural interpretation of the theory of risk-Averse investor behaviour. Recently, SSD-based models of portfolio choice have been proposed; these assume that a reference distribution is available and a portfolio is constructed, whose return distribution dominates the reference distribution with respect to SSD. We present an empirical study which analyses the effectiveness of such strategies in the context of enhanced indexation.

Tema: general: 

• Ciencias›Matemáticas

A Spatio-Temporal Bayesian Network Classifier for Understanding Visual Field Deterioration

REA Auditado

Progressive loss of the field of vision is characteristic of a number of eye diseases
such as glaucoma which is a leading cause of irreversible blindness in the world. Recently,
there has been an explosion in the amount of data being stored on patients who suffer from visual deterioration including field test data, retinal image data and patient demographic data. However, there has been relatively little work in modelling
the spatial and temporal relationships common to such data.

Tema: general: 

• Ciencias›Matemáticas

Topics in complex systems

REA Auditado

Fundamental laws of physics, although successful in explaining many phenomena observed in nature and society, cannot account for the behaviour of complex, non-Hamiltonian systems. Much effort has been devoted to better understanding the topological properties of these systems. Neither ordered nor disordered, these systems of high variability are found in many areas of science. Studies on sandpiles, earthquakes and lattice gases have all yielded evidence of complexity in the form of power law distributions.

Tema: general: 

• Ciencias›Matemáticas

Spectral and wave function statistics in Quantum digraphs

REA Auditado

Spectral and wave function statistics of the quantum directed graph, QdG, are studied. The crucial feature of this model is that the direction of a bond (arc) corresponds to the direction of the waves propagating along it. We pay special attention to the full Neumann digraph, FNdG, which consists of pairs of antiparallel arcs between every node, and differs from the full Neumann graph, FNG, in that the two arcs have two incommensurate lengths. The spectral statistics of the FNG (with incommensurate bond lengths) is believed to be universal, i.e.

Tema: general: 

• Ciencias›Matemáticas

Metaheuristics for the waste collection vehicle routing problem with time windows

REA Auditado

In this thesis there is a set of waste disposal facilities, a set of customers at which waste is collected and an unlimited number of homogeneous vehicles based at a single depot. Empty vehicles leave the depot and collect waste from customers, emptying themselves at the waste disposal facilities as and when necessary. Vehicles return to the depot empty. We take into consideration time windows associated with customers, disposal facilities and the depot. We also have a driver rest period. The problem is solved heuristically.

Tema: general: 

• Ciencias›Matemáticas

Tabu search for ship routing and scheduling

REA Auditado

This thesis examines exact and heuristic approaches to solve the Ship Routing and Scheduling Problem (SRSP). The method was developed to address the problem of loading cargos for many customers using heterogeneous vessels. Constraints relate to delivery time windows imposed by customers, the time horizon by which all deliveries must be made and vessel capacities. The objective is to minimise the overall operation cost, where all customers are satisfied.

Tema: general: 

• Ciencias›Matemáticas