• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 78
  • 53
  • 45
  • 26
  • 7
  • 7
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 497
  • 209
  • 208
  • 208
  • 208
  • 208
  • 77
  • 77
  • 57
  • 52
  • 49
  • 42
  • 40
  • 39
  • 25
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Structured editing of handwritten mathematics

Mendes, Alexandra Sofia Ferreira January 2012 (has links)
Teaching effectively requires a clear presentation of the material being taught and interaction with the students. Studies have shown that Tablet PCs provide a good technological support for teaching. The aim of the work presented in this thesis is to design a structure editor of handwritten mathematics that explores the facilities provided by Tablet PCs. The editor is made available in the form of a class library that can be used to extend existing tools. The central feature of the library is the definition of structure for handwritten mathematical expressions which allows syntactic manipulation of expressions. This makes it possible to accurately select, copy and apply algebraic rules, while avoiding the introduction of errors. To facilitate structured manipulation, gestures are used to apply manipulation rules and animations that demonstrate the use of these rules are introduced. Also, some experimental features that can improve the user’s experience and the usability of the library are presented. Furthermore, it is described how to integrate the library into existing tools. In particular, Classroom Presenter, a system developed to create interactive presentations using a Tablet PC, is extended and used to demonstrate how the library’s features can be used in some teaching scenarios. Although there are limitations in the current system, tests performed with teachers and students indicate that it can help to improve the experience of teaching and learning mathematics, particularly calculational mathematics.
242

Understanding the professionally risky behaviour of young adults in using social media

Carter, Chris James January 2016 (has links)
Social media play an increasingly important role in people's professional as well as personal lives, providing the means for seeking employment, consolidating social relationships with colleagues, and building professional reputation. However, in doing so, people submit their digital presence to the scrutiny and judgment of both current and prospective employers. This poses risks to professional reputation, and particularly for young adults who have been found to engage in professionally risky behaviour when using social media, despite appearing aware of the potentially damaging reputational consequences. A mixed methods approach was adopted across five empirical studies to examine potential factors influencing this behaviour, and subsequently, how reputational risk may be mitigated in the use of social media amongst young adults. The first two studies, a document analysis of 30 organisational social media policies and a thematic analysis of 14 semi-structured interviews with university employees, emphasised the need for employees to closely self-regulate both the content of their posts and their online of connections with others. Expressions of individuality and personal views on social media were identified as representing both threats and opportunities for professional reputation, emphasising the need for vigilance and careful consideration of professional consequences, even within restricted online spaces. The third study examined whether individual differences in personality traits associated with “professionally appropriate” online behaviour predicted the extent to which 210 Sixth Form College and undergraduate students considered the professional consequences of their social media use. No significant effect of personality was found, although students transitioning into their final year of study reported significantly greater consideration than students at other stages of study. Examining whether increased perceptions of professional audience may have been a factor, the fourth study surveyed 257 final-year undergraduates and found that when employer surveillance on Facebook was judged by young adults to be psychologically closer to immediate experience, perceptions of profession risk in relation to controversial or anti-social content upon the site were greater. In contrast, this was not the case for content depicting poor spelling or grammar, where typically low risk perceptions suggested a potential “blind spot” in risk awareness. The fifth study involved 20 semi-structured interviews with graduate trainees and interns, finding that advice from parents and university careers services was particularly influential in increasing perceptions of professional risk whilst applying for jobs, and connecting with other professionals online became a salient factor following organisational entry. The findings of this thesis demonstrated limited support for either a lack of digital reputation management skill or dispositions towards particular personality traits as factors influencing the professionally risky online behaviour of young adults. In contrast, the findings indicated a role for the psychological distance with which young adults construed professional audience online, and the aforementioned gap in risk awareness. These findings imply that interventions should focus primarily on building awareness of professional risk associated with poor spelling and grammar, whilst focusing more upon ways to induce psychological proximity of professional audience for addressing behaviours where the professional risks are already understood. In doing so, however, it is concluded that the shorter-term benefits of helping young adults to maintain their employability must be balanced against the longer-term consequences of normalising the chronic self-censorship of individuality amongst members of this cohort.
243

Synthesis and evaluation of inhibitors of cell wall biosynthesis in Mycobacterium tuberculosis

May, Terry J. January 2016 (has links)
The emergence of drug-resistant strains of tuberculosis has led to a demand for the development of new antibiotics. One new target is the cell wall biosynthesis enzyme UDP-Galp mutase (UGM), which aids the formation of the bacteria’s characteristic mycolic acid cell wall. LQ10 and LQ6 were discovered through a library screen. The synthesis of LQ10 was achieved along with 4 analogues. Another class of compounds, 2-aminothiazoles, were produced. Thirteen of these compounds were produced and along with the LQ10 analogues, initially gave encouraging results in silico. To test their biological activity, a fluorescent probe was synthesised for use in a high-throughput fluorescence polarization (FP) assay against UDP-Galp Mutase which was expressed from E. coli. The compounds were screened using the fluorescence polarisation assay initially at a concentration of 50 µM, 9 of which demonstrated >70 % inhibition of UGM. Two of which had inhibition greater than 90 %. These preliminary results suggest that some of these compounds are, and can be developed into potent UGM inhibitors. However, it should be noted that these are only single-point results due to limitations in the quantity of UGM available, and that these will need be repeated in triplicate to determine any errors and give more reliable values.
244

Molecular epidemiology and transmission dynamics of S. uberis bovine clinical mastitis

Davies, P. L. January 2016 (has links)
Mastitis remains one of the most common, costly and intractable diseases affecting the dairy cattle industry worldwide. In spite of concerted efforts meaningful progress in reducing the incidence of mastitis has been limited over the past thirty years by our partial understanding of the epidemiology of key pathogens, such as S.uberis. The aim of this thesis was to investigate the epidemiology of S.uberis mastitis by analysis of the population structure and transmission dynamics of clinical mastitis patterns within and between commercial dairy herds in England and Wales. In Chapter 3 Multi Locus Sequence Typing (MLST) was used to describe the sub-species (sequence type) genetic heterogeneity of S.uberis isolates collected from a longitudinal study of clinical mastitis on 52 farms. The clinical cases were classified according the pattern of occurrence of the sequence types in the herds. The findings suggested that a small subset of MLST sequence types were disproportionally important in the epidemiology of S.uberis mastitis, with cow-to-cow transmission of S.uberis, potentially occurring in the majority of herds in the United Kingdom; this may be the most important route of S.uberis transmission in approximately one third of herds. In Chapter 4 cow and herd level variables, including monthly recorded milk constituents, yield and parity were evaluated against the clinical case classifications defined in Chapter 3. The temporal relationships between clinical cases and classifications were also evaluated as potential predictors of transmission dynamics within a herd. The findings indicated that the time interval between clinical cases classified by genotype as potentially contagious transmission was significantly shorter than that between successive mastitis clinical cases attributed to environmental transmission. The distribution of clinical cases throughout lactation also indicated a higher proportion of potentially contagious isolates were cultured from clinical cases originating from lactation rather than the dry period compared to those attributed to environmental transmission. In Chapter 5 Matrix Assisted Laser Desorption (MALDI) mass spectroscopy was used to generate spectral profiles of S.uberis isolates cellular composition. Spectral profiles were used successfully as an alternative method of discriminating between clinical mastitis isolates associated with contagious transmission from those associated with and environmental origin of infection defined in Chapter 3. The findings of this chapter demonstrated marked variation between herds in the spectral profiles of isolates from the same clinical case classification. In Chapter 6 selected isolates of S.uberis associated with contagious transmission and persistent intramammary infections were sequenced using next generation technology and compared by core genome multi locus sequence typing (cgMLST) to evaluate the discriminatory capacity of the MLST and MALDI. The results from this chapter confirmed the importance of the herd unit in the genotypic population structure of S.uberis suggested by the results of Chapter 5 and also support the results of Chapter3 which suggest ‘low grade’ contagious transmission of S.uberis is superimposed on a ubiquitous, environmental S.uberis mastitis pattern in many herds This thesis demonstrated that the S.uberis population is complex with variation at the bacterial, cow and herd level suggesting different patterns of disease and bacterial evolution occurring in different circumstances. Categorisation of sub-species of S.uberis within herds as being transmitted via contagious or environmental routes appears to be eminently achievable using modern, high throughput technologies; this could lead to a step change in mastitis control.
245

Towards emotional and socially realistic game companions with personality

Chowanda, Andry January 2018 (has links)
This thesis presents a fully integrated and modular framework for social and emotional game companion that focuses on realistic social interaction between the player and Non-Player Characters (NPCs) in a game environment. Moreover, this thesis proposes integrated computational models for a formulation of action selection rules based on the game companion's personality, the relation between player and game companion and the perceived (non-)verbal actions to enhance the NPC's believability and the player's interaction in a game context. The rules were derived from data collections of both human-human and human-machine interactions. This thesis argues that NPC with such capability will accommodate a new experience when playing games. To illustrates the effectiveness of the proposed framework and computational models, the author implemented the framework and computational models into two game scenarios: The Smile Game where a human player who abides in the real world played with an ECA who inhabits a virtual world. The second scenario was The Skyrim Game, where an avatar represented the human player, who played with a virtual NPC in a virtual world. With a total of 117 participants in 217 interactions with the system, the results show that the players evidently perceived the NPCs' personality in accordance with the one set to them. The NPCs' ability to display emotions appropriately also provides the feeling of immersion in games to the players. Moreover, the ability to forge relationships naturally with the game companions gives the sentimental feeling towards the game companions. The main contribution of the work presented to the field of Intelligence Virtual Agents specifically in the domain of computer games, in this thesis is A fully integrated and modular framework for social-affect-aware game design complete with the computational models for social interaction with game companions. Several games have been built in several scenarios with simple social interactions between players and the game companions using the framework and computational models proposed to explore the opportunities of the framework and models. Finally, this thesis also presents some scenarios for data collections to construct interaction rules for game companions.
246

Metabolic engineering of Clostridium autoethanogenum

Liew, Fung Min January 2016 (has links)
Gas fermentation has emerged as a promising technology that converts waste gases containing CO, CO2 and H2 (also known as syngas) into fuels and chemical commodities. Employed by LanzaTech Inc., Clostridium autoethanogenum is an industrial acetogen that converts gases into ethanol, 2,3-butanediol, acetate, and lactate. Metabolic engineering offers unique opportunities to eliminate side-products, synthesize novel, high-value molecules as diversification strategies, and increase productivities of natural products. However, there had been no scientific reports of genetic manipulation of this acetogen so the overall goal of this PhD project was to develop genetic tools for this gas-utilizing microorganism and construct a hyper-ethanol producing strain via metabolic engineering. The formulation of electroporation and conjugation procedures allowed exogenous DNA to be routinely introduced into the bacterial host. ClosTron mutagenesis and Allele-Coupled Exchange (ACE) techniques were fully exemplified in this bacterium during the construction of knockout, in-frame deletion, and overexpression mutants. Carbon monoxide dehydrogenases (cooS1, cooS2 and acsA) were specifically targeted to elucidate their roles in supporting CO oxidation and carbon fixation. In the ethanol formation pathway, inactivation of bi-functional aldehyde/alcohol dehydrogenases (adhE1 and adhE2) impaired growth on pure CO but elevated ethanol titres. Conversely, inactivation of the more highly expressed aldehyde:ferredoxin oxidoreductase (aor1), but not the weakly expressed aor2, significantly reduced ethanol production, highlighting the importance of aor1 in autotrophic ethanol formation. A double KO mutant of aor1 and aor2 was also generated via ClosTron mutagenesis and pyrE-mediated allelic exchange. In an effort to engineer a robust biocatalyst, the native chaperone systems groESL and/or grpE-dnaK-dnaJ were overexpressed in C. autoethanogenum, resulting in enhanced tolerance towards ethanol, heat and salts. In summary, this study demonstrated the genetic tractability of C. autoethanogenum and revealed gene targets for future metabolic engineering of a hyper-ethanol producing acetogen.
247

Deriving knowledge of household behaviour from domestic electricity usage metering

Dent, Ian January 2015 (has links)
The electricity market in the UK is undergoing dramatic changes and requires a transformation of existing practices to meet the current and forthcoming challenges. One aspect of the solution is the deployment of demand side management (DSM) programmes to influence domestic behaviour patterns for the benefit of the overall network. Effective deployment of DSM requires segmentation of the population into a small number of groupings. Using a database of electricity meter data collected at a frequency of five minutes over a year from several hundred houses, households are clustered based on the shape of the average daily electricity usage profile. A novel method, incorporating evaluation criteria beyond compactness, of evaluating the resulting groupings is defined and tested. The results indicate the potentially most useful algorithms for use with load profile clustering. Patterns within the electricity meter data are approximated and symbolised to allow motifs (representing repeated behaviours) to be identified. Uninteresting motifs are automatically identified and discarded. The different possible parameters, including size of motif and number of symbols used in representing the data, are explored and the most appropriate values found for use with electricity meter data motif detection. The concept of variability of regular behaviour within a household is introduced and methods of representing the variability are considered. The novel method of using variability in timing of motifs is compared to other techniques and the results tested using the previously defined evaluation criteria. Combining the generated motif data with the meter data to produce a single set of archetypes does not produce more useful results for use with DSM. However, creating complementary sets of archetypes based on each set of data, provides a more complete understanding of the households and allows for better targeting of DSM initiatives.
248

Using technology based student led discussions to promote constructive learning in Chinese primary schools

Bao, Wenwen January 2017 (has links)
The many valuable aspects of Chinese education have been seen throughout the world. For example Chinese teachers have been invited into the UK to instruct UK teachers on how to improve the quality of Mathematics education there. However, from 2001 onwards the government of China has sought to import pedagogies from the West in order to tackle observed problems with their own education system. Many scholars feel the problems the government were trying to address – the lack of critical thinking, a tendency to rote learning and an exam focused mind-set – would lead to failure for these techniques. However, these studies have all been with older students in high school and beyond. Little or no work has focused on students in the primary grades. Casual observation of Chinese primary school students would imply that they have no trouble in coming up with ideas and discussing them. The initiative for the study in this thesis has therefore been to see if this age range of students would be open to discussion based classes. A study was undertaken to determine if the removal of the teacher from control of the discussion would facilitate this age group to partake in face to face discussion. Other aims were to see whether constructivist learning would result or would the face based, hierarchical Confucian background education system prevent this. The original study was encouraging and as a result a technology based intervention was developed to see if this could help to improve the discussion and would allow further opportunities for students to feel able to engage. To encourage this the new system was also made anonymous. A third study was introduced to see if this approach could prove beneficial to the teachers also as to get such approaches adopted in Chinese schools the teachers would also need to see the benefit of the approach. The resultant study has demonstrated that not only do Chinese primary school students engage in face to face study but they also can be further encouraged by use of an online system. Further developments also indicate that the system can be valuable to the teachers who can use it as an aid to find out the preconceptions of their students and thus help them in developing a more focused curriculum. The thesis ends by describing ways in which this study can continue to have a positive impact in developing students’ critical thinking skills.
249

Towards user centric regulation : exploring the interface between information technology law and human computer interaction

Urquhart, Lachlan January 2017 (has links)
This thesis investigates the role of technology designers in regulation. Emerging information technologies are complex to regulate. They require new strategies to support traditional approaches. We focus on the use of technology design as a regulatory tool. Whilst this solution has significant conceptual traction, what it means in practice is not clear. Deeper investigation of the role of the design community in regulation is necessary to move these strategies from theory into practice. We structure our analysis by asking: how can we understand the role of designers in regulation of emerging technologies? We answer this question from four primary perspectives: conceptual, legal, practical and design. We situate our investigation within the context of the domestic internet of things and information privacy by design. We adopt an overtly multidisciplinary approach, critically assessing how to bring together the human computer interaction and information technology law communities. To do this, we utilise a range of qualitative methods, including case studies, documental and legal analysis, semi structured expert interviews, questionnaires, focus groups, workshops, and development, testing and evaluation of a design tool. Our contributions are as follows: Conceptually, we provide a critical investigation of the role of technology designers in regulation by consolidating, evaluating and aligning a range of theoretical perspectives from human computer interaction (HCI) and information technology (IT) law. We draw these together through the concept of user centric regulation. This concept advocates a user focused, interaction led approach to position the role of designers in regulation. It draws on the turn to human values and societal issues in HCI, and the increasing reliance in IT law on design for regulation of emerging technologies. Legally, we present two detailed case studies of emerging technologies (domestic internet of things and smart metering) mapping the emerging legal landscape and challenges therein. We situate the role of designers, as regulators, within this space, and show how they can respond accordingly through their user centric focus. Practically, we analyse experiences from leading experts in technology design and regulation to understand the challenges of doing information privacy by design (PbD) for the IoT. We present our findings within the framing of technological, business and regulatory perspectives. Lastly, we present a design tool, ‘information privacy by design cards’, to support designers in doing PbD. This tool has been designed, tested and refined, providing us with a practical approach to doing user centric regulation. Based on our findings from using the cards, we provide the concept of regulatory literacy to clearly conceptualise the role of designers in regulation.
250

Hyper-heuristics and fairness in examination timetabling problems

Muklason, Ahmad January 2017 (has links)
Examination timetabling is a challenging optimisation problem in operations research and artificial intelligence. The main aim is to spread exams evenly throughout the overall time period to facilitate student comfort and success; however, existing examination timetabling solvers neglect fairness by optimising the sum or average of the objective function value without considering its distribution among students or other stakeholders. The balance between quality of the overall timetable and fairness (global fairness and within a cohort) is a major concern, thus the latter is added as a new objective function and quality indicator of examination timetables. The objective function is also considered from the perspectives of multiple stakeholders of examination timetabling (i.e. students, invigilators, markers and estates), as opposed to viewing the objective function as an aggregate function. These notions make the problem become a multi-objective optimisation problem. We study sum of power rather than linear summation to enforce fairness and concurrently minimise the objective function, using some perturbation-based hyper- heuristics approaches to optimise the standard objective function. Secondly, multi-stage approach is studied (generating initial feasible solution, improving the standard quality of solution and then improving fairness), to improve the fairness objective function. Given that the standard objective function and fairness objective function conflict, we then studied several multi-objective algorithms employed within the framework of hyper-heuristics. The proposed hyper-heuristic algorithms mainly can be divided into two approaches: classical scalarisation technique-based weighted sum and Tchebyce↵; and population-based non-dominated sorting memetic algorithm II (NSMA-II) and artificial bee colony and strength pareto evolutionary 2 (SPEA2) hybrid (ABC-SPEA2). The experiments were conducted over two multi-objective examination timetabling problem formulations (i.e. with fairness and with multiple stakeholder perspectives), tested over problem instances from four different datasets: Carter, Nottingham, Yeditepe and ITC 2007. The experimental results over multi-objective examination timetabling problem with fairness showed that in terms of the standard objective function the proposed approach could produce results comparable with the best known solutions reported in the literature, whilst in the same time could be forced to be fairer that does or does not compensate on worsening the standard objective function. Fairness within a cohort could be improved much better than global fairness and treating as multi-objective problem could help the search for near-optimal standard objective function escape from local optima trap. The scalarisation technique based hyper-heuristics outperforms the population-based hyper-heuristic. The advantage of treating examination timetabling problem as multi-objective problem is that approximations of the Pareto optimal solutions give the optimal trade-o↵ between standard objective function, fairness among all students, and fairness within a cohort. In addition, the decision maker also can view the solution from multiple stakeholders view. We believe that by giving this more detailed information, the decision maker of examination timetable could make better decisions.

Page generated in 0.0269 seconds