Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"Combinatorial optimisation"”.
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Combinatorial optimisation for sustainable cloud computing
… from the realm of mathematical modeling and combinatorial optimisation. We introduce a novel combinatorial optimisation problem suitable for modeling core consolidation problems arising in workload management in data centres. This problem extends on the well-known bin packing problem. We …
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Evolutionary computation applied to combinatorial optimisation problems
… genetic algorithms (GA) when applied to hard optimisation problems. In particular it examines the problem of selecting and implementing appropriate genetic operators in order to meet the validity constraints for constrained optimisation problems. The problem selected is the travelling salesman …
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Polynomially searchable exponential neighbourhoods for sequencing problems in combinatorial optimisation
… used in local search algorithms for classes of combinatorial optimisation problems. We introduce a method, called dynasearch, of constructing new neighbourhoods, and of viewing some previously derived exponentially sized neighbourhoods which are searchable in polynomial time. We produce new …
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Evolutionary combinatorial optimisation for energy storage scheduling, and web-based power systems analysis using PHP
… thesis: the formulation of a novel evolutionary combinatorial optimisation algorithm for energy storage system (ESS) scheduling, and web-based power systems analysis (WBPSA) using PHP programming. An increase in electricity demand usually calls for reinforcement of the network equipment to handle …
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Combinatorial and Robust Optimisation Models and Algorithms for Railway Applications
This thesis deals with an investigation of combinatorial and robust optimisation models to solve railway problems. Railway applications represent a challenging area for operations research. In fact, most problems in this context can be modelled as combinatorial optimisation problems, in which the …
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Improving Manufacturing Systems Using Integrated Discrete Event Simulation and Evolutionary Algorithms
… of genetic algorithms based multi-objective combinatorial optimisation and discrete event simulation modelling tool to investigate the effect of variability in high variety/low volume manufacturing by considering the effect of improvement of selected performance measures on each other. Also, …
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Set-based Particle Swarm Optimisation for Dynamic Optimisation Problems
Many real-world optimisation problems are inherently dynamic, defined by changes in their underlying properties over time. Real-world problems also frequently require optimisation over discrete-valued decision variables. However, the solution of problems that are simultaneously dynamic and …
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Heuristic Solution Approaches to the Solid Assignment Problem
… Problem (SAP), is a challenging problem in combinatorial optimisation. While the ordinary or 2-dimensional assignment problem is in the P-class, SAP which is an extension of it, is NP-hard. SAP is the problem of allocating n jobs to n machines in n factories such that exactly one job is …
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An Extended Ant Colony Optimisation Approach for the Mass Customisation Paradigm
… for a mass customisation paradigm. Ant Colony Optimisation (ACO) Algorithms have been used successfully in the past to tackle combinatorial optimisation problems in dynamic environments as its inbuilt mechanisms allow it to adapt to new environments. In this work we use a novel architecture …
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The Plant Propagation Algorithm for Discrete Optimisation
… heuristics for the so called NP-hard problems of optimisation. A particular algorithm which has been recently introduced and shown to be effective in continuous optimisation is the Plant Propagation Algorithm or PPA. Here, we intend to extend it to cope with combinatorial optimisation. In order to …
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Scheduling and Resource Efficiency Balancing: Discrete Species Conserving Cuckoo Search for Scheduling in an Uncertain Execution Environment
… presents a variation of the RCPSP that considers optimisation of projects in an uncertain environment where resources are modelled to adapt to their environment and, as the result of this, improve their efficiency. Secondly, modification of a novel evolutionary computation method Cuckoo Search …
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Ant Colony Optimisation for Dynamic and Dynamic Multi-objective Railway Rescheduling Problems
… is to investigate the application of ant colony optimisation (ACO) to dynamic and dynamic multiobjective railway rescheduling problems. ACO is a promising approach for dynamic combinatorial optimisation problems as its inbuilt mechanisms allow it to adapt to the new environment while retaining …
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Adiabatic processes, noise, and stochastic algorithms for quantum computing and quantum simulation
… can be used to solve classical problems like combinatorial optimisation problems and simulated annealing. We are able to reach a new bound of time cost for the algorithm which has a potential to achieve a speed up over standard adiabatic quantum computing. The second topic is to understand the …
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Upper and lower bounds for the fixed spectrum frequency assignment problem
… consequently the problem, which is treated as a combinatorial optimisation problem, can be represented by an undirected weighted graph.<br/><br/>A summary of some of the integer programming formulations which model the problem is presented, together with a brief dimensional study of them. …
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Approaches for solving some scheduling and routing problems
… solutions, and lower bounds, for three difficult combinatorial optimisation problems.<br/>The supply ship travelling salesman problem is a simplification of a situation faced by a naval logistics coordinator who must direct a support vessel tasked with resupplying ships in a fleet. It is a …
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Fuzzy Evolutionary Approaches for Bus and Rail Driver Scheduling
… exist because of the NP-hard nature of this combinatorial optimisation problem. This thesis presents two evolutionary algorithms, namely a Genetic Algorithm and a Simulated Evolution algorithm, attempting to model and solve the driver scheduling problem in new ways. At the heart of both …
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Constraint-based local search for container freight rail scheduling
… assignment problem, a well-known hard combinatorial optimisation problem. The experimental results have shown that the proposed method can obtain high quality solutions that are as good as or close to the solutions obtained from the existing methods, but with using significantly less …
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Valued Constraint Satisfaction Problems over Infinite Domains
… is the computational complexity of certain combinatorial optimisation problems called \emph{valued constraint satisfaction problems}, or \emph{VCSPs} for short. The requirements and optimisation criteria of these problems are expressed by sums of \emph{(valued) constraints} (also called …
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Optimal control reformulation for the solution of decision-making problems in chemical engineering
… scheduling, obviating the need for any form of combinatorial optimisation. Two-Point Boundary Value Problems (TPBVPs) are examined and solved utilising a double shooting approach, where the initial TPBVP is reformulated into a set of Ordinary Differential Equations (ODEs) and is solved as a …
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Agent-Based Modelling of Decentralized Ant Behaviour using High Performance Computing
… have proven to be very effective in solving combinatorial optimisation problems, especially in the field of telecommunication. The major challenge in social insect research is understanding how colony-level behaviour emerges from individual interactions. Models to date focus on simple …
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