Asphalt pavements are usually constructed in several layers and most of pavement design and evaluation techniques assume that adjacent asphalt layers are fully bonded together and no displacement is developed between them. However, full bonding is not always achieved and a number of pavement failures have been linked to poor bond condition Theoretical research showed that the distribution of stresses, strains and deflections within the pavement structure is highly influenced by the bond condition between the adjacent layers. Slippage at the interface between the binder course and the base could significantly reduce the life of the overall pavement structure. If slippage occurs within the interface between the surfacing and the binder course, the maximum horizontal tensile strain at the bottom of the surfacing becomes excessive and causing the rapid surfacing failure. This condition becomes worse when a significant horizontal load exists. This thesis is concerned with the assessment of bond between asphalt layers. The main objective of this thesis is to provide guidance for assessing bond between asphalt layers, in order to facilitate the construction of roads with more assurance of achieving the design requirements. Further modification to the modified Leutner test has been performed. An investigation regarding the torque bond test and the effect of trafficking on bond have also been undertaken. A bond database on the modified Leutner test has been developed. An analysis has been performed to estimate the achievable values of bond strengths on typical UK road constructions obtained from the bond database. The values were then compared to the results from an analytical analysis to predict the required bond strength at the interface and other standards in Germany and Switzerland to recommend specification limits of bond strength for UK roads.

No description available.

At the present time (1978) new roads in the United Kingdom are designed empirically. However, over approximately the last twenty years pavement technologists throughout the world have been advocating fundamentally based procedures. Such procedures, when applied to flexible pavements, require a detailed knowledge of the two main modes of failure, fatigue of the bituminous bound layers and excessive permanent deformation of the pavement as a whole. The research described herein was aimed at improving knowledge of the permanent deformation behaviour of flexible pavements, and at developing a technique for predicting this deformation which could be incorporated in a fundamental design procedure. Three laboratory experimental pavements were trafficked with a rolling wheel facility under conditions of constant temperature, load and speed, and the resulting deformations were monitored. These deformations were compared with predictions using models developed from the results of repeated load characterisation tests on the pavement materials and utilising a digital computer. A review of previous work is presented ill two parts, the first considering the resilient and permanent deformation response of pavement materials, the second considering proposals for the prediction of permanent deformation in pavements. The development of the wheel loading facility, and the construction, instrumentation and measurements from the pavements are described briefly. More attention is given to the theoretical approach, materials characterisation testing and the prediction of resilient and permanent deformation response of the pavements. The prediction techniques and their accuracy are assessed, the problems involved in the development of such procedures are discussed, and the conclusions which can be drawn from the work are presented. A number of suggestions regarding further work in this field are made. Finally, an Appendix considers an alternative to the method of modelling permanent deformation presented in the main part of the text.

This thesis tackles the Urban Transit Network Design Problem (UTNDP) which involves determining an efficient set of routes and schedules for public transit networks. The UTNDP can be divided into five subproblems as identified by Ceder and Wilson [24]: i) network design, ii) frequency setting, iii) timetable development, iv) bus scheduling, and v) driver scheduling, with each problem requiring the output of the previous. In this thesis we focus on the first two stages, network design and frequency setting. We identify that evaluation is a major bottleneck for the network design problem and propose alternative approaches with the aim of decreasing the computation time. A multi-objective evolutionary algorithm (MOEA) for the network design problem is then presented that trades-off the passenger and operator costs. A passenger wishes to travel from their origin to destination in the shortest possible time, whereas the network operator must provide an adequate level of service whilst balancing the operational costs i.e. number of drivers and vehicles. The proposed MOEA combines a heuristically seeded population, using a novel construction algorithm, with several genetic operators to produce improved results compared with the state of the art from the literature. We provide an evaluation of the effectiveness of the genetic operators showing that improved performance, in terms of the number of dominating and nondominating solutions, is achieved as the size of the problem instance increases. Four surrogate models are proposed and an empirical evaluation is performed to assess the solution quality versus run trade-off in each case. It is found that surrogate models perform well on large problem instances producing improved Pareto sets compared with the original algorithm due to the increased amount of evolution that is allowed to occur under fixed time limits. Finally we empirically evaluate three multi-objective approaches for the frequency setting problem utilising the route networks produced during our network design procedure. It is shown that a MOEA based on the NSGAII framework provides the best quality solutions due to the cost of evaluation when using a neighbourhood based approach such as multi-objective tabu search. Constraints on vehicle capacity and fleet size are then introduced. It is shown that such constraints vastly reduce the number of solutions from network design that can successfully undergo frequency setting. A discussion is then presented highlighting the limitations of conducting network design and frequency setting separately along with alternative approaches that could be used in the future. We conclude this thesis by summarising our findings and presenting topics for future works.

It has previously been assumed that the vibration discomfort of standing people can be estimated using the same procedures developed from for seated people. In this thesis, the discomfort of standing people exposed to vibration was investigated to improve understanding of the mechanisms responsible for discomfort and construct a model that may be used to predict the discomfort of standing railway passengers. The first of five experiments using the method of magnitude estimation and 6-s periods of vibration investigated how the discomfort of standing subjects exposed to fore-and-aft, lateral, and vertical sinusoidal vibration depends on the frequency of vibration. From the judgements of 12 subjects at each of the 16 preferred one-third octave centre frequencies from 0.5 to 16 Hz, frequency weightings were constructed for each direction. For vertical vibration, the weighting was similar to that recommended in standards, but the weightings for fore-and-aft and lateral vibration differed from that previously assumed. Horizontal vibration caused loss of balance at frequencies less than about 3 Hz, and it caused discomfort in the legs at higher frequencies. Vertical vibration caused discomfort in the upper body. To adjust the frequency weightings according to differences in sensitivity between directions, the second experiment with 12 subjects compared the discomfort caused by 4-Hz sinusoidal vibration in the fore-and-aft, lateral, the vertical directions. It was found that sensitivity was greater for fore-and-aft vibration than lateral vibration at frequencies less than 4 Hz and weightings were determined to assist the evaluation vibration in all three directions. The third experiment investigated the extent to which postural supports used by standing train passengers (vertical bar, shoulder support, and back support) affect discomfort caused by fore-and-aft and lateral vibration in the range 0.5 to 16 Hz. Supports that created a new path for the transmission of vibration to the upper-body increased discomfort over the range 4 to 16 Hz. The fourth experiment investigated how the root-mean-square method, the basic evaluation method in current standards but known to underestimate the discomfort caused by motions containing occasional peaks, could be modified for the evaluation of non-sinusoidal vibration. Using 1-Hz and 8-Hz random vibrations with a range of crest factors it was found that the discomfort of standing subjects was better predicted with an exponent around 3, rather than an exponent of 2 implicit in r.m.s. averaging. The final experiment determined a method for predicting the discomfort of tri-axial vibration. The cube root of the sum of the cubes of the discomfort caused by the single-axis components gave good estimates of the total discomfort for both 1-Hz and 4-Hz tri-axial vibration. Since it was found in the first experiment that the discomfort was generally proportional to the acceleration at the power 0.7. these results suggest that the root-sum-of-squares of the accelerations gives good estimates of the total discomfort for tri-axial vibration . The results of all experiments were combined in an empirical model for predicting the discomfort of standing people exposed to 6-s periods of vibration. It is concluded that there are two distinctly different mechanisms responsible for vibration discomfort when standing: postural instability and body vibration. Postural instability is dominant with horizontal vibration at frequencies less than about 3 Hz, whereas body vibration is dominant with vertical vibration and with horizontal vibration at frequencies greater than about 3 Hz. The discomfort of standing people is similar to the discomfort of seated people for vertical vibration, but fundamentally different with horizontal vibration due to postural instability at low frequencies and vibration attenuation in the legs at higher frequencies

The study of applying soft computing techniques, such as evolutionary computation and simulation, to the deployment of intelligent autonomous vehicles (IAVs) in container terminals is the focus of this thesis. IAVs are a new type of intelligent vehicles designed for transportation of containers in container terminals. This thesis for the first time investigates how IAVs can be effectively accommodated in container terminals and how much the performance of container terminals can be improved when IAVs are being used. In an attempt to answer the above research questions, the thesis makes the following contributions: First, the thesis studies the fleet sizing problem in container terminals, an important design problem in container terminals. The contributions include proposing a novel evolutionary algorithm (with superior results to the state-of-the-art CPLEX solver), combining the proposed evolutionary algorithm with Monte Carlo simulation to take into account uncertainties, validating results of the uncertain case with a high fidelity simulation, proposing different robustness measures, comparing different robust solutions and proposing a dynamic sampling technique to improve the performance of the proposed evolutionary algorithm. Second, the thesis studies the impact of IAVs on container terminals’ performance and total cost, which are very important criteria in port equipment. The contributions include developing simulation models using realistic data (it is for the first time that the impact of IAVs on containers terminals is investigated using simulation models) and applying a cost model to the results of the simulation to estimate and compare the total cost of the case study with IAVs against existing trucks. Third, the thesis proposes a new framework for the simulations of container terminals. The contributions include developing a flexible simulation framework, providing a user library for users to create 3D simulation models using drag-and-drop features, and allowing users to easily incorporate their optimisation algorithms into their simulations.

The container transportation problem involves designing routing plans for a fleet of vehicles to accommodate requests from multiple ports. A request is a transshipment activity that involves loading a commodity at the source port and then unloading it at the destination port. This problem is closely related to the classic vehicle routing problem (VRP). This thesis investigates a real-world, multi-shift container transportation problem with a limited fleet size. In this problem, requests are sent from the customs office via declaration forms. Each declaration form contains several container transport tasks that share the same time window, source port and destination port. The time windows for container transportation in this problem can generally span across several shifts, thus container transportations can be arranged at any shift. Delaying some transportations to later shifts may cause the violation of time window constraints. As a result, strategies that prioritise tasks with closer deadline need to be developed to ensure that all tasks can be completed. This thesis presents the following research efforts towards the container transshipment problem. Firstly, two formulations have been proposed to describe the problem, in which the representation of transshipment requests are simplified as nodes. The network of the ports is then discussed and, based on the network, three sets of problem instances are introduced. This thesis then introduces several insertion-based heuristics, which are able to generate solutions that complete all container transshipment tasks. In order to further reduce the travelling distance in the solutions, two multi-neighbourhood algorithms are implemented and experimental results are presented. The characteristics of solutions are discussed to get a deeper understanding of the problem characteristics. The dynamic version of the problem, in which declaration forms arrive over time, is then studied. A discrete event simulation framework is developed to accommodate the experiment of various commodity holding strategies. This research leads to an intelligent container transportation system that automates the task assignment.

The branch of algorithms that uses adaptive methods to select or tune heuristics, known as hyper-heuristics, is one that has seen a large amount of interest and development in recent years. With an aim to develop techniques that can deliver results on multiple problem domains and multiple instances, this work is getting ever closer to mirroring the complex situations that arise in the corporate world. However, the capability of a hyper-heuristic is closely tied to the representation of the problem it is trying to solve and the tools that are available to do so. This thesis considers the design of such problem domains for hyper-heuristics. In particular, this work proposes that through the provision of high-quality data and tools to a hyper-heuristic, improved results can be achieved. A definition is given which describes the components of a problem domain for hyper-heuristics. Building on this definition, a domain for the Vehicle Routing Problem with Time Windows is presented. Through this domain, examples are given of how a hyper- heuristic can be provided extra information with which to make intelligent search decisions. One of these pieces of information is a measure of distance between solution which, when used to aid selection of mutation heuristics, is shown to improve results of an Iterative Local Search hyper-heuristic. A further example of the advantages of providing extra information is given in the form of the provision of a set of tools for the Vehicle Routing Problem domain to promote and measure ’fairness’ between routes. By offering these extra features at a domain level, it is shown how a hyper-heuristic can drive toward a fairer solution while maintaining a high level of performance.

According to National Highway Traffic Safety Administration’s (NHTSA) official reports, many traffic accidents have been caused due to drivers’ drowsiness. Previous work based on computer vision techniques achieved drowsiness detection, usually with special hardware that depended on laboratory environments. To overcome limitations of these approaches, a natural light based surveillance system is proposed. The system achieves drowsiness detection in three stages: face segmentation, drowsiness feature extraction and classification. To segment faces, a simplified skin colour model is developed to compute colour distance maps from original facial images. Candidate faces are located using colour distance maps in conjunction with centres of gravity of individual faces. Gegenbauer features are then applied to capture shape information that is related to drowsiness. The computation of these features is based on moments derived from coefficients of Gegenbauer polynomials. To detect the behaviour of a subject, image sequences of his/her face are classified into drowsy and nondrowsy states by a Hidden Markov Model using Gegenbauer features. A sequence is classified as drowsy if the number of drowsy states in the Hidden Markov Model reaches a pre-defined threshold. To evaluate the proposed system, experiments are conducted using 65 video clips that contained a mixture of 54 drowsy and 11 non-drowsy behaviours. The proposed system detected 47 drowsy behaviours from these video clips successfully, and thus resulting in a detection rate of 87%. This proposed system is independent of infrared illuminators that were found to be unreliable in previous systems. Furthermore, the new system deploys multiple facial features and presents a more accurate description of drowsiness rather than a single facial feature proposed by previous authors.

New technological advances and the requirements to increasingly abide by new safety laws in engineering design projects highly affects industrial products in areas such as automotive, aerospace and railway industries. The necessity arises to design reduced-cost hi-tech products with minimal complexity, optimal performance, effective parameter robustness properties, and high reliability with fault tolerance. In this context the control system design plays an important role and the impact is crucial relative to the level of cost efficiency of a product. Measurement of required information for the operation of the design control system in any product is a vital issue, and in such cases a number of sensors can be available to select from in order to achieve the desired system properties. However, for a complex engineering system a manual procedure to select the best sensor set subject to the desired system properties can be very complicated, time consuming or even impossible to achieve. This is more evident in the case of large number of sensors and the requirement to comply with optimum performance. The thesis describes a comprehensive study of sensor selection for control and fault tolerance with the particular application of an ElectroMagnetic Levitation system (being an unstable, nonlinear, safety-critical system with non-trivial control performance requirements). The particular aim of the presented work is to identify effective sensor selection frameworks subject to given system properties for controlling (with a level of fault tolerance) the MagLev suspension system. A particular objective of the work is to identify the minimum possible sensors that can be used to cover multiple sensor faults, while maintaining optimum performance with the remaining sensors. The tools employed combine modern control strategies and multiobjective constraint optimisation (for tuning purposes) methods. An important part of the work is the design and construction of a 25kg MagLev suspension to be used for experimental verification of the proposed sensor selection frameworks.