Manufacturing systems simulation using the principles of system dy

Manufacturing is the largest single contributor to the global economy. The evolution of consumer demands has pressurised companies into producing a larger variety of products, with improved specifications, reduced costs, and shorter lead times. In this context, companies have found simulation techniques useful in their manufacturing systems design processes; simulation based on Discrete Event Simulation (DES) is the preferred technique. The complexity of manufacturing systems, and the mechanisms of DES, means that the simulation task often consumes excessive time and resources, such as data, software, and training. Evidence suggests that an alternative modelling technique, named System Dynamics (SD), is also appropriate for conducting this task. SD has been applied successfully in other fields, where its graphical notation is considered beneficial. However, the lack of an SD tool that is tailored toward manufacturing systems has prevented industry from adopting this technique more extensively. This thesis determines the extent to which SD can provide a credible alternative to DES in the manufacturing system design process. Information concerning DES, SD and practitioners' needs was gathered from published literature and from an interview survey. A functional prototype of a tool based on the SD principles, but tailored to model manufacturing systems was then developed. Three case studies then provided valuable information concerning the requirements of industry and the capabilities of the SD technique. This research programme has found SD to be sufficiently accurate and quicker than DES tools under certain conditions, requiring less data and skills. In addition, the user interface appears to have had a significant impact on the lack of adoption of SD techniques within the manufacturing sector. Simp1ifications made by this technique can reduce both model building and model execution time, and thus, experimentation time. However, evidence suggests that DES is still more prevalent, and that further work is required to develop SD based tools tailored to manufacturing systems. Therefore, this thesis provides a much improved understanding of the capabilities of SD as an aid to manufacturing systems design

Semantic technologies: from niche to the mainstream of Web 3? A comprehensive framework for web Information modelling and semantic annotation

Context: Web information technologies developed and applied in the last decade have considerably changed the way web applications operate and have revolutionised information management and knowledge discovery. Social technologies, user-generated classification schemes and formal semantics have a far-reaching sphere of influence. They promote collective intelligence, support interoperability, enhance sustainability and instigate innovation. Contribution: The research carried out and consequent publications follow the various paradigms of semantic technologies, assess each approach, evaluate its efficiency, identify the challenges involved and propose a comprehensive framework for web information modelling and semantic annotation, which is the thesis’ original contribution to knowledge. The proposed framework assists web information modelling, facilitates semantic annotation and information retrieval, enables system interoperability and enhances information quality. Implications: Semantic technologies coupled with social media and end-user involvement can instigate innovative influence with wide organisational implications that can benefit a considerable range of industries. The scalable and sustainable business models of social computing and the collective intelligence of organisational social media can be resourcefully paired with internal research and knowledge from interoperable information repositories, back-end databases and legacy systems. Semantified information assets can free human resources so that they can be used to better serve business development, support innovation and increase productivity

Affective Computing for Emotion Detection using Vision and Wearable Sensors

The research explores the opportunities, challenges, limitations, and presents advancements in computing that relates to, arises from, or deliberately influences emotions (Picard, 1997). The field is referred to as Affective Computing (AC) and is expected to play a major role in the engineering and development of computationally and cognitively intelligent systems, processors and applications in the future. Today the field of AC is bolstered by the emergence of multiple sources of affective data and is fuelled on by developments under various Internet of Things (IoTs) projects and the fusion potential of multiple sensory affective data streams. The core focus of this thesis involves investigation into whether the sensitivity and specificity (predictive performance) of AC, based on the fusion of multi-sensor data streams, is fit for purpose? Can such AC powered technologies and techniques truly deliver increasingly accurate emotion predictions of subjects in the real world? The thesis begins by presenting a number of research justifications and AC research questions that are used to formulate the original thesis hypothesis and thesis objectives. As part of the research conducted, a detailed state of the art investigations explored many aspects of AC from both a scientific and technological perspective. The complexity of AC as a multi-sensor, multi-modality, data fusion problem unfolded during the state of the art research and this ultimately led to novel thinking and origination in the form of the creation of an AC conceptualised architecture that will act as a practical and theoretical foundation for the engineering of future AC platforms and solutions. The AC conceptual architecture developed as a result of this research, was applied to the engineering of a series of software artifacts that were combined to create a prototypical AC multi-sensor platform known as the Emotion Fusion Server (EFS) to be used in the thesis hypothesis AC experimentation phases of the research. The thesis research used the EFS platform to conduct a detailed series of AC experiments to investigate if the fusion of multiple sensory sources of affective data from sensory devices can significantly increase the accuracy of emotion prediction by computationally intelligent means. The research involved conducting numerous controlled experiments along with the statistical analysis of the performance of sensors for the purposes of AC, the findings of which serve to assess the feasibility of AC in various domains and points to future directions for the AC field. The AC experiments data investigations conducted in relation to the thesis hypothesis used applied statistical methods and techniques, and the results, analytics and evaluations are presented throughout the two thesis research volumes. The thesis concludes by providing a detailed set of formal findings, conclusions and decisions in relation to the overarching research hypothesis on the sensitivity and specificity of the fusion of vision and wearables sensor modalities and offers foresights and guidance into the many problems, challenges and projections for the AC field into the future

Investigating students' learning of differential equations in physics

There are numerous cases in physics where the value of a quantity and changes in that quantity are related. For example, the speed of an object depends on its acceleration; the radioactivity of a sample depends on the amount of the sample present. Except in highly idealised settings, the analysis of these cases requires students to recognize, set up, and solve an ordinary differential equation (ODE). In many universities, ODEs are studied in mathematics before they are applied in physics. However, the aims of mathematicians and physicists can be very different. Mathematics modules tend to emphasise theoretical aspects of ODEs. In contrast, physics modules often emphasise modelling. This project is a multi-stage investigation that began by identifying the issues experienced by physics students during their study of ODEs before addressing them through the design and implementation of a set of tutorials. Having surveyed a cohort of physics students who completed a typical service module on ODEs, we found that many of them possessed a fragmented concept image of ODEs and insufficient instrumental understanding. Fifteen tutorials were designed to address these issues. Issues with instrumental understanding (primarily the manipulation of exponents and indefinite integration), and broadening the students’ concept image were the focuses. The effectiveness of the tutorials was measured using immediate pre/post-testing, delayed post-tests, and interviews with students. Together, these revealed significant gains in the understanding of ODEs as well as an appreciation of the guided-inquiry approach employed. Although some gaps in instrumental understanding were found to remain, students are hampered more by an incomplete concept image of ODEs. By studying the conceptual difficulties of physics students with ODEs and designing a guided teaching-learning sequence, we have been able to improve students’ conceptual understanding of ODEs without impacting negatively on their instrumental understanding

System response times in a simulated driving task : effects on performance, visual attention, subjective state and time estimation

The utilisation of navigation systems in cars has given rise to road safety concerns, and the design and functionality of such systems must therefore be adjusted to the users’ needs, since they have to divide their attention between driving and the operation of the navigation system. The study was aimed at finding the optimum system response time (SRT) which would enable a driver to focus as much as possible on the road while attaining an efficient task completion time using an electronic navigational system. The research project consists of two separate experiments and was completed by 10 subjects. Experiment 1 included a temporal reproduction task and a secondary memory task. The subjects had to memorise two symbols and then reproduce six time spans ranging from 1 to 30 s to provide a baseline measurement of their time estimation abilities. Experiment 2 consisted of a simulated automobile driving task. While driving in the simulator the subjects completed a memorising task displayed on a touch screen. The task was presented with seven different system response times (SRTs) ranging from 0 to 30 s. The effects of different SRTs on the eye movement from road to monitor, regarding the duration of fixation and the frequency of change were evaluated. The distribution of gazes to the secondary task was analysed to provide information about the time estimation performance in the driving simulator. Other dependent variables tested were the accuracy of selected items, memory game performance, drive performance and the subjective state of the test person. The results of this study can be employed to find the optimum duration of inter-task delays for in-vehicle technical devices.PsychologyM.A. (Psychology

Construction of an adaptive e-learning environment to address learning styles and an investigation of the effect of media choice

This study attempted to combine the benefits of multimedia learning, adaptive interfaces, and learning style theory by constructing a novel e-learning environment. The environment was designed to accommodate individual learning styles while students progressed through a computer programming course. Despite the benefits of individualised instruction and a growing worldwide e-learning market, there is a paucity of guidance on how to effectively accommodate learning styles in an online environment. Several existing learning-style adaptive environments base their behaviour on an initial assessment of the learner's profile, which is then assumed to remain stable. Consequently, these environments rarely offer the learner choices between different versions of content. However, these choices could cater for flexible learning styles, promote cognitive flexibility, and increase learner control. The first research question underlying the project asked how learning styles could be accommodated in an adaptive e-learning environment. The second question asked whether a dynamically adaptive environment that provides the learner with a choice of media experiences is more beneficial than a statically adapted environment. To answer these questions, an adaptive e-learning environment named iWeaver was created and experimentally evaluated. iWeaver was based on an introductory course in Java programming and offered learning content as style-specific media experiences, assisted by additional learning tools. These experiences and tools were based on the perceptual and information processing dimension of an adapted version of the Dunn and Dunn learning styles model. An experimental evaluation of iWeaver was conducted with 63 multimedia students. The analysis investigated the effect of having a choice of multiple media experiences (compared to having just one static media experience) on learning gain, enjoyment, perceived progress, and motivation. In addition to these quantitative measurements, learners provided qualitative feedback at the end of each lesson. Data from 27 participants were sufficiently complete to be analysed. For the data analysis, participants were divided into two groups of high and low interest in programming and Java, then into two groups of high and low experience with computers and the Internet. Both group comparisons revealed statistically significant differences for the effect of choice. Having a choice of media experiences proved beneficial for learners with low experience but detrimental for learners with high experience or interest. These findings suggest that the effect of choice appears to be strongly influenced by the learner's background. It is hypothesised that encouraging a more active learner role in educational systems would expand the positive influence of choice to a wider range of learners. The study has contributed some weight to the argument that for certain groups of learners, it is more beneficial to view learning style as a flexible, rather than a stable construct. As a practical implication, it seems advisable to collect data on prior experience, interest, and the initial learning style distribution of the target audience before developing environments comparable to iWeaver

'Second-Stage' Iorwerth: Textual Change and Development in Medieval Welsh Legal Manuscripts

This thesis explores a set of legal manuscripts from medieval Wales, known as the Iorwerth recension. These manuscripts are placed in their historical and material settings, and a view of the development of the text is given. From an original thirteenth-century core, a story is told of the recension’s development across a range of further rearrangements and uses across the Middle Ages. The use of the Iorwerth text is analysed for what it might reveal of the intentions and mindset of the copyist. In the second half of the thesis, a more traditional textual account is given of the Iorwerth recension. Volume II contains tables and editions to accompany the arguments in the first volume

Personal data sovereignty : a sustainable interface layer for a human centered data ecosystem

The reality of ubiquitous computing and exponential personal data generation challenges the notion of privacy, as Surveillance Capitalism and Nation State endeavour to record and analyse personal data with the objective of leveraging influence and control. It is argued that this centralised model threatens to stifle the digital economy, destabilise our democracy, and fundamentally change our social norms. Real-time, non-statistical datasets offer huge potential for governance, commerce, and social cohesion. But the positive benefit of the emerging data driven society is threatened by the tensions formed through asymmetric power imbalances that manifest across a narrow band of walled gardened web services.In recent years work has been undertaken to counter the centralised model, despite these efforts there has been limited change in trajectory or sustained adoption of decentralised technologies. This research is designed to explore and evaluate the Decentralised Internet. Investigating the challenge of designing usable, sustainable tools for the everyday participant. This research engages mixed methods to explore the trajectory of technologies and public attitudes. Domain experts are consulted to explore application and value proposition. Practice extends the decentralised trajectory to consider participant journeys, interaction, and the interface layer.This research concludes that the core technological infrastructure now exists to facilitate a genuine Decentralised Internet and that an identity layer facilitated through Blockchain technology is progressing the domain towards Self Sovereign Identity (SSI). This research extends this trajectory through Conceptual Modelling to define a Sovereign Boundary Mechanism (SBM), an independent realm of interaction which enables the principles of decentralisation. Analysis suggests that this interaction is high in friction, requiring considerable internalised cognition and prior knowledge in order to engage.This research concludes that the concept of network privacy is poorly defined and miss-understood, and that participants struggle to see its value across context and cultures. Investigation indicates that the Decentralised Internet cannot be marketed, and instead has to supersede the centralised model through defined innovations. This research argues that a cohesive strategy is required to achieve adoption, one which collectively identifies and develops offerings of value through design thinking while defining a consistent narrative to deliver targeted solutions within cultural contexts.This research makes a theoretical contribution to knowledge by connecting the domains of Self Sovereign Identity (SSI) and Human Data Interaction (HDI). The research establishes the fundamental spheres of interaction for an analogue SSI system through what is defined as a Sovereign Boundary Mechanism (SBM). The research identifies issues and paradox’s relating to an SBM and identifies further required investigation and research. This research makes a practical contribution to knowledge by presenting a framework and resource for further innovation and development, the wider problem space for a Human-Centred Data Ecosystem is defined, and finally the research contributes to a wider adoption strategy through the identification of value proposition