3,306 research outputs found
Radial Dynamics of Pickering-stabilised Endoskeletal Antibubbles and Their Components in Pulsed Ultrasound
Liquids containing microscopic antibubbles may have theranostic applications in harmonic diagnostic ultrasonic imaging and in ultrasound-assisted drug delivery. Presently there are no known agents available with the acoustic properties required for use in both of these applications. The Pickering-stabilised antibubble may possess the de- sired acoustic properties to be such a theranostic agent. An antibubble is a gas bubble containing at least one incompressible core. An antibubble is inherently unstable and thus needs to be stabilised to exist for longer than a moment. One such stabilising method, involving the adsorption of nanoparticles to gas–liquid interfaces, is called Pickering stabilisation. A Pickering-stabilised antibubble responds to an incident sound field by means of radial pulsation and other, more complicated, dynamics.
Despite the potential application of microscopic antibubbles in theranostics, their dynamic behaviour and the acoustic regimes in which this behaviour occurs are not known.
The purpose of this research was to predict the dynamic response of Pickering- stabilised antibubbles to pulsed ultrasound, and to identify and quantify the contribution of each of the Pickering-stabilised antibubble components to that behaviour. Radial excursions of antibubbles and their components during ultrasound exposure were extracted from high-speed footage. The applied ultrasound had a centre frequency of 1 MHz and pressure amplitudes between 0.20 MPa and 1.30 MPa. Moreover, damping coefficients, pulsation phases, and excursions of antibubbles and antibubble components were computed with equations describing a forced mass–spring–dashpot system and an adapted Rayleigh-Plesset equation. Over a range of driving pressure amplitudes, fragmentation thresholds were computed for antibubbles of varying size, core volume, shell stiffness, and driving frequency. In addition, the feasibility of an antibubble component for the disruption of cell walls was tested. From the experimental data, it was found that antibubble contractions and expansions were symmetrical and predictable at an acoustic amplitude of 0.20 MPa, whilst the pulsations were asymmetrical and less predictable at an acoustic amplitude of 1.00 MPa. These results show that the presence of the core inside of the antibubble hampers the contraction of a collapsing antibubble and ameliorates its stability. Consequently, Pickering-stabilised antibubbles appear to be feasible candidates for ultrasonic imaging, with greater stability than the agents currently in use.
Micron-sized antibubbles, much smaller than resonant size, were computed to have a pulsation phase difference of up to 16 th of a cycle with respect to free gas bubbles. The difference in oscillation phase is a result of the increased damping coefficient caused by the friction of the internal components and shell of the antibubble. This indicates that altering the damping of the shell or skeletal material of minute antibubbles can alter the degree to which the particle’s oscillation is in phase with the sound field.
The shell stiffness of Pickering-stabilised microbubbles without incompressible contents was measured to be 7.6 N m−1 throughout low-amplitude sonication. Un- der high-amplitude sonication, the maximum expansions of microbubbles, measured from high-speed camera footage, were either agreeing with those computed for Pickering-stabilised microbubbles or corresponding to greater values. The differing oscillation amplitudes for similarly sized microbubbles is attributed to shell disruption of different severity.
For a 3-μm radius antibubble with a 90% core radius, subjected to a pulse of centre frequency 1 MHz, the fragmentation threshold was computed to drastically increase with shell stiffness. At a driving frequency of 13 MHz, the fragmentation threshold was computed to correspond to a mechanical index less than 0.4, irrespective of shell stiffness. Shell stiffness changes the resonance frequency, and thus the fragmentation threshold of antibubbles. This means that the resonance frequency of an extremely low concentration and quantity of homogeneous agent can be determined using microscopy. At driving frequencies above 1 MHz, the fragmentation threshold was computed to correspond to a mechanical index of less than 0.5, irrespective of shell stiffness.
Antibubbles exposed to high-amplitude ultrasound were found to have an exponential fragment size distribution. This brings us closer to understanding and controlling disruption and material release for these particles. If the pressure of the regime is known, the number of antibubble fragments produced can be theoretically determined.
Under low-amplitude ultrasound exposure, hydrophobic particles, a common component of antibubbles, were observed to jet through wood fibre cell walls, without causing visible internal structural damage to these cells. Hydrophobic particles can thus act as inertial cavitation nuclei which collapse asymmetrically close to solid boundaries such as wood pulp fibres. This indicates that hydrophobic particles on their own may be used for applications such as trans-dermal drug delivery.
The dynamic response of Pickering-stabilised antibubbles to ultrasound has been predicted. Furthermore the respective behaviour of Pickering-stabilised antibubble components under theranostic ultrasound conditions has been identified. This work has led to a straightforward way to determine the elasto-mechano properties of small samples of contrast agent.
Whilst possessing some theranostic properties, Pickering-stabilised antibubbles may be more suitable as replacements for current diagnostic agents. Hydrophobic particles, a current constituent of the Pickering-stabilised antibubble, may however, prove to be promising theranostic agents
InGAME international pathway to collaboration: Collaboration in Games UK-China
In 2019 the Arts & Humanities Research Council (AHRC) funded a series of projects as part of its UK-China Creative Partnerships Programme. Led by Abertay University in partnership with academic and industry partners across the UK and China, InGAME International was funded through this AHRC programme with the aim of studying the potential for UK-China cooperation and collaboration in the computer games sector. The project is linked to the AHRC Creative Industries Cluster, InGAME: Innovation for Games and Media Enterprise, which is also led by Abertay University in partnership with the University of Dundee and University of St Andrews. The games industry is one of the largest and fastest growing sectors in both the UK and the Chinese creative economies. In 2023, China was the largest gaming market globally with revenue forecast at 7.94 billion in the UK (Statista, 2023). The growth in China’s market has long been the source of appeal for UK game developers and publishers seeking new routes to market. However, the divergence between the UK and China in terms of market profile, consumption patterns, leading companies, technologies, regulation, licensing, management, and business culture has presented ongoing difficulties for any UK based developer interested in engagement in- or with- China. It is from this basis that the current study sought to consolidate industry, legal, and regulatory knowhow with a view to providing a valuable resource to games professionals and researchers who have interests in UK-China collaboration. This Pathway to Collaboration report curates the cumulative knowledge and insight generated during the InGAME International programme, with an intended audience of games industry professionals and researchers interested in UK-China collaboration. At the heart of the research is an unprecedented qualitative study that involved in-depth interviews with 47 leading experts from the UK, China and other territories and with knowledge of games development, business, publishing, marketing, localisation, IP, copyright, regulation, markets, and sales. This report is the first comprehensive qualitative study to investigate the intersection between the UK and China games industries and markets at this scale and depth, providing readers with an invaluable, interactive resource that will support professionals and researchers to initiate new collaborations between the two nations.</p
Configuration Management of Distributed Systems over Unreliable and Hostile Networks
Economic incentives of large criminal profits and the threat of legal consequences have pushed criminals to continuously improve their malware, especially command and control channels. This thesis applied concepts from successful malware command and control to explore the survivability and resilience of benign configuration management systems.
This work expands on existing stage models of malware life cycle to contribute a new model for identifying malware concepts applicable to benign configuration management. The Hidden Master architecture is a contribution to master-agent network communication. In the Hidden Master architecture, communication between master and agent is asynchronous and can operate trough intermediate nodes. This protects the master secret key, which gives full control of all computers participating in configuration management. Multiple improvements to idempotent configuration were proposed, including the definition of the minimal base resource dependency model, simplified resource revalidation and the use of imperative general purpose language for defining idempotent configuration.
Following the constructive research approach, the improvements to configuration management were designed into two prototypes. This allowed validation in laboratory testing, in two case studies and in expert interviews. In laboratory testing, the Hidden Master prototype was more resilient than leading configuration management tools in high load and low memory conditions, and against packet loss and corruption. Only the research prototype was adaptable to a network without stable topology due to the asynchronous nature of the Hidden Master architecture.
The main case study used the research prototype in a complex environment to deploy a multi-room, authenticated audiovisual system for a client of an organization deploying the configuration. The case studies indicated that imperative general purpose language can be used for idempotent configuration in real life, for defining new configurations in unexpected situations using the base resources, and abstracting those using standard language features; and that such a system seems easy to learn.
Potential business benefits were identified and evaluated using individual semistructured expert interviews. Respondents agreed that the models and the Hidden Master architecture could reduce costs and risks, improve developer productivity and allow faster time-to-market. Protection of master secret keys and the reduced need for incident response were seen as key drivers for improved security. Low-cost geographic scaling and leveraging file serving capabilities of commodity servers were seen to improve scaling and resiliency. Respondents identified jurisdictional legal limitations to encryption and requirements for cloud operator auditing as factors potentially limiting the full use of some concepts
InGAME international pathway to collaboration: Collaboration in Games UK-China
In 2019 the Arts & Humanities Research Council (AHRC) funded a series of projects as part of its UK-China Creative Partnerships Programme. Led by Abertay University in partnership with academic and industry partners across the UK and China, InGAME International was funded through this AHRC programme with the aim of studying the potential for UK-China cooperation and collaboration in the computer games sector. The project is linked to the AHRC Creative Industries Cluster, InGAME: Innovation for Games and Media Enterprise, which is also led by Abertay University in partnership with the University of Dundee and University of St Andrews. The games industry is one of the largest and fastest growing sectors in both the UK and the Chinese creative economies. In 2023, China was the largest gaming market globally with revenue forecast at 7.94 billion in the UK (Statista, 2023). The growth in China’s market has long been the source of appeal for UK game developers and publishers seeking new routes to market. However, the divergence between the UK and China in terms of market profile, consumption patterns, leading companies, technologies, regulation, licensing, management, and business culture has presented ongoing difficulties for any UK based developer interested in engagement in- or with- China. It is from this basis that the current study sought to consolidate industry, legal, and regulatory knowhow with a view to providing a valuable resource to games professionals and researchers who have interests in UK-China collaboration. This Pathway to Collaboration report curates the cumulative knowledge and insight generated during the InGAME International programme, with an intended audience of games industry professionals and researchers interested in UK-China collaboration. At the heart of the research is an unprecedented qualitative study that involved in-depth interviews with 47 leading experts from the UK, China and other territories and with knowledge of games development, business, publishing, marketing, localisation, IP, copyright, regulation, markets, and sales. This report is the first comprehensive qualitative study to investigate the intersection between the UK and China games industries and markets at this scale and depth, providing readers with an invaluable, interactive resource that will support professionals and researchers to initiate new collaborations between the two nations.</p
Indie encounters: exploring indie music socialising in China
Indie music, a genre deeply rooted in rock and punk music, is renowned for its independence from major commercial record labels. It has emerged as a choice for music consumers seeking alternatives to mainstream popular music, catering to a niche music preference. The minority nature of indie music not only provides its lovers with a profound space for individual expression and a sense of collective belonging but also introduces other challenges into their social lives. Recently, the field of music sociology has proposed a more diverse perspective to observe and analyse the intricate role of music for individuals and society. In this context, regarding Chinese indie music lovers with niche music preferences, how their indie music practices integrate into their social lives and how they navigate their niche music tastes have become worthwhile topics of exploration.
Drawing on interviews with 31 Chinese indie music lovers and extensive online ethnography, this thesis investigates how Chinese indie music lovers comprehend and engage with indie music, and how the power of indie music shapes them and their social behaviours.
I employ the theoretical framework of ‘music in action’ (Hennion, 2001; DeNora, 2011, 2016) and symbolic interactionism (Mead, 1934; Goffman, 1959; Blumer, 1969) to examine the dynamic and multifaceted roles of indie music in the social lives of Chinese indie music lovers. I develop a concept of ‘music socialising’ to delve into several key aspects of music lovers’ social practices. I contend that through various forms of musical activities such as music selection, live music attendance, and digital practices, indie music lovers exhibit strategic and reflexive characteristics in their music practices. These practices actively contribute to constructing and maintaining self and identity, negotiating social ties, and forming and mediating collectivity within a broader social landscape. It is through these processes that the music practices of Chinese indie music lovers are endowed with meanings, thereby shaping their social reality. This thesis presents a rich and nuanced picture of the social experiences of Chinese indie music lovers, uncovering the transformative power of their indie music practices. It presents a compelling argument for the significance of music as a social agency, highlighting the complex interactions between music, individuals, and society. By bridging theoretical insights with rich empirical data, this thesis contributes to our understanding of the socio-cultural dimensions of music, offering fresh perspectives on the role of indie music in contemporary Chinese society
Distributed Ledger Technology (DLT) Applications in Payment, Clearing, and Settlement Systems:A Study of Blockchain-Based Payment Barriers and Potential Solutions, and DLT Application in Central Bank Payment System Functions
Payment, clearing, and settlement systems are essential components of the financial markets and exert considerable influence on the overall economy. While there have been considerable technological advancements in payment systems, the conventional systems still depend on centralized architecture, with inherent limitations and risks. The emergence of Distributed ledger technology (DLT) is being regarded as a potential solution to transform payment and settlement processes and address certain challenges posed by the centralized architecture of traditional payment systems (Bank for International Settlements, 2017). While proof-of-concept projects have demonstrated the technical feasibility of DLT, significant barriers still hinder its adoption and implementation. The overarching objective of this thesis is to contribute to the developing area of DLT application in payment, clearing and settlement systems, which is still in its initial stages of applications development and lacks a substantial body of scholarly literature and empirical research. This is achieved by identifying the socio-technical barriers to adoption and diffusion of blockchain-based payment systems and the solutions proposed to address them. Furthermore, the thesis examines and classifies various applications of DLT in central bank payment system functions, offering valuable insights into the motivations, DLT platforms used, and consensus algorithms for applicable use cases. To achieve these objectives, the methodology employed involved a systematic literature review (SLR) of academic literature on blockchain-based payment systems. Furthermore, we utilized a thematic analysis approach to examine data collected from various sources regarding the use of DLT applications in central bank payment system functions, such as central bank white papers, industry reports, and policy documents. The study's findings on blockchain-based payment systems barriers and proposed solutions; challenge the prevailing emphasis on technological and regulatory barriers in the literature and industry discourse regarding the adoption and implementation of blockchain-based payment systems. It highlights the importance of considering the broader socio-technical context and identifying barriers across all five dimensions of the social technical framework, including technological, infrastructural, user practices/market, regulatory, and cultural dimensions. Furthermore, the research identified seven DLT applications in central bank payment system functions. These are grouped into three overarching themes: central banks' operational responsibilities in payment and settlement systems, issuance of central bank digital money, and regulatory oversight/supervisory functions, along with other ancillary functions. Each of these applications has unique motivations or value proposition, which is the underlying reason for utilizing in that particular use case
Assessing the Role and Regulatory Impact of Digital Assets in Decentralizing Finance
This project will explore the development of decentralized financial (DeFi) markets since the first introduction of digital assets created through the application of a form of distributed ledger technology (DLT), known as blockchain, in 2008. More specifically, a qualitative inquiry of the role of digital assets in relation to traditional financial markets infrastructure will be conducted in order to answer the following questions:
(i) can the digital asset and decentralized financial markets examined in this thesis co-exist with traditional assets and financial markets, and, if so,
(ii) are traditional or novel forms of regulation (whether financial or otherwise) needed or desirable for the digital asset and decentralized financial markets examined herein?
The aim of this project will be to challenge a preliminary hypothesis that traditional and decentralized finance can be compatible; provided, that governments and other centralized authorities approach market innovations as an opportunity to improve existing monetary infrastructure and delivery of financial services (both in the public and private sector), rather than as an existential threat. Thus, this thesis seeks to establish that, through collaborating with private markets to identify the public good to which DeFi markets contribute, the public sector can foster an appropriate environment which is both promotive and protective of the public interest without unduly stifling innovation and progress
Multidisciplinary perspectives on Artificial Intelligence and the law
This open access book presents an interdisciplinary, multi-authored, edited collection of chapters on Artificial Intelligence (‘AI’) and the Law. AI technology has come to play a central role in the modern data economy. Through a combination of increased computing power, the growing availability of data and the advancement of algorithms, AI has now become an umbrella term for some of the most transformational technological breakthroughs of this age. The importance of AI stems from both the opportunities that it offers and the challenges that it entails. While AI applications hold the promise of economic growth and efficiency gains, they also create significant risks and uncertainty. The potential and perils of AI have thus come to dominate modern discussions of technology and ethics – and although AI was initially allowed to largely develop without guidelines or rules, few would deny that the law is set to play a fundamental role in shaping the future of AI. As the debate over AI is far from over, the need for rigorous analysis has never been greater. This book thus brings together contributors from different fields and backgrounds to explore how the law might provide answers to some of the most pressing questions raised by AI. An outcome of the Católica Research Centre for the Future of Law and its interdisciplinary working group on Law and Artificial Intelligence, it includes contributions by leading scholars in the fields of technology, ethics and the law.info:eu-repo/semantics/publishedVersio
Design Knowledge for Virtual Learning Companions from a Value-centered Perspective
The increasing popularity of conversational agents such as ChatGPT has sparked interest in their potential use in educational contexts but undermines the role of companionship in learning with these tools. Our study targets the design of virtual learning companions (VLCs), focusing on bonding relationships for collaborative learning while facilitating students’ time management and motivation. We draw upon design science research (DSR) to derive prescriptive design knowledge for VLCs as the core of our contribution. Through three DSR cycles, we conducted interviews with working students and experts, held interdisciplinary workshops with the target group, designed and evaluated two conceptual prototypes, and fully coded a VLC instantiation, which we tested with students in class. Our approach has yielded 9 design principles, 28 meta-requirements, and 33 design features centered around the value-in-interaction. These encompass Human-likeness and Dialogue Management, Proactive and Reactive Behavior, and Relationship Building on the Relationship Layer (DP1,3,4), Adaptation (DP2) on the Matching Layer, as well as Provision of Supportive Content, Fostering Learning Competencies, Motivational Environment, and Ethical Responsibility (DP5-8) on the Service Layer
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