7,895 research outputs found
Mobile heritage practices. Implications for scholarly research, user experience design, and evaluation methods using mobile apps.
Mobile heritage apps have become one of the most popular means for audience
engagement and curation of museum collections and heritage contexts. This
raises practical and ethical questions for both researchers and practitioners, such
as: what kind of audience engagement can be built using mobile apps? what are
the current approaches? how can audience engagement with these experience
be evaluated? how can those experiences be made more resilient, and in turn
sustainable? In this thesis I explore experience design scholarships together with
personal professional insights to analyse digital heritage practices with a view to
accelerating thinking about and critique of mobile apps in particular. As a result,
the chapters that follow here look at the evolution of digital heritage practices,
examining the cultural, societal, and technological contexts in which mobile
heritage apps are developed by the creative media industry, the academic
institutions, and how these forces are shaping the user experience design
methods. Drawing from studies in digital (critical) heritage, Human-Computer
Interaction (HCI), and design thinking, this thesis provides a critical analysis of
the development and use of mobile practices for the heritage. Furthermore,
through an empirical and embedded approach to research, the thesis also
presents auto-ethnographic case studies in order to show evidence that mobile
experiences conceptualised by more organic design approaches, can result in
more resilient and sustainable heritage practices. By doing so, this thesis
encourages a renewed understanding of the pivotal role of these practices in the
broader sociocultural, political and environmental changes.AHRC REAC
Faster inference from state space models via GPU computing
Funding: C.F.-J. is funded via a doctoral scholarship from the University of St Andrews, School of Mathematics and Statistics.Inexpensive Graphics Processing Units (GPUs) offer the potential to greatly speed up computation by employing their massively parallel architecture to perform arithmetic operations more efficiently. Population dynamics models are important tools in ecology and conservation. Modern Bayesian approaches allow biologically realistic models to be constructed and fitted to multiple data sources in an integrated modelling framework based on a class of statistical models called state space models. However, model fitting is often slow, requiring hours to weeks of computation. We demonstrate the benefits of GPU computing using a model for the population dynamics of British grey seals, fitted with a particle Markov chain Monte Carlo algorithm. Speed-ups of two orders of magnitude were obtained for estimations of the log-likelihood, compared to a traditional ‘CPU-only’ implementation, allowing for an accurate method of inference to be used where this was previously too computationally expensive to be viable. GPU computing has enormous potential, but one barrier to further adoption is a steep learning curve, due to GPUs' unique hardware architecture. We provide a detailed description of hardware and software setup, and our case study provides a template for other similar applications. We also provide a detailed tutorial-style description of GPU hardware architectures, and examples of important GPU-specific programming practices.Publisher PDFPeer reviewe
Readily available drugs and other interventions to potentially improve the efficacy of immune checkpoint blockade in cancer
To improve the efficacy of immune checkpoint inhibitors (ICIs) for cancer treatment, various strategies, including combination therapies with repurposed drugs, are being explored. Several readily available interventions with potential to enhance programmed death 1 (PD-1) blockade have been identified. However, these interventions often remain overlooked due to the lack of financial incentives for their development, making them financial orphans. This review summarizes current knowledge regarding off-label drugs, supplements, and other readily available interventions that could improve the efficacy of PD-1 blockade. The summary of each intervention includes the proposed mechanism of action for combination with checkpoint inhibitors and data from animal and human studies. Additionally, we include summaries of common interventions to be avoided by patients on PD-1 blockade. Finally, we present approaches for conducting further studies in patients, with the aim of expediting the clinical development of these interventions. We strive to increase awareness of readily available combination therapies that may advance cancer immunotherapy and help patients today
LIPIcs, Volume 251, ITCS 2023, Complete Volume
LIPIcs, Volume 251, ITCS 2023, Complete Volum
Efficient abstraction of clock synchronization at the operating system level
Distributed embedded systems are emerging and gaining importance in various domains, including industrial control applications where time determinism – hence network clock synchronization – is fundamental. In modern applications, moreover, this core functionality is required by many different software components, from OS kernel and radio stack up to applications. An abstraction layer devoted to handling time needs therefore introducing, and to encapsulate time corrections at the lowest possible level, the said layer should take the form of a timer device driver offering a Virtual Clock to the entire system. In this paper we show that doing so introduces a nonlinearity in the dynamics of the clock, and we design a controller based on feedback linearization to handle the issue. To put the idea to work, we extend the Miosix RTOS with a generic interface allowing to implement virtual clocks, including the newly designed controller that we call FLOPSYNC-3 after its ancestor. Also, we introduce the resulting virtual clock in the TDMH [20] real-time wireless mesh protocol
Auditable and performant Byzantine consensus for permissioned ledgers
Permissioned ledgers allow users to execute transactions against a data store, and retain proof of their execution in a replicated ledger. Each replica verifies the transactions’ execution and ensures that, in perpetuity, a committed transaction cannot be removed from the ledger. Unfortunately, this is not guaranteed by today’s permissioned ledgers, which can be re-written if an arbitrary number of replicas collude. In addition, the transaction throughput of permissioned ledgers is low, hampering real-world deployments, by not taking advantage of multi-core CPUs and hardware accelerators.
This thesis explores how permissioned ledgers and their consensus protocols can be made auditable in perpetuity; even when all replicas collude and re-write the ledger. It also addresses how Byzantine consensus protocols can be changed to increase the execution throughput of complex transactions. This thesis makes the following contributions:
1. Always auditable Byzantine consensus protocols. We present a permissioned ledger system that can assign blame to individual replicas regardless of how many of them misbehave. This is achieved by signing and storing consensus protocol messages in the ledger and providing clients with signed, universally-verifiable receipts.
2. Performant transaction execution with hardware accelerators. Next, we describe a cloud-based ML inference service that provides strong integrity guarantees, while staying compatible with current inference APIs. We change the Byzantine consensus protocol to execute machine learning (ML) inference computation on GPUs to optimize throughput and latency of ML inference computation.
3. Parallel transactions execution on multi-core CPUs. Finally, we introduce a permissioned ledger that executes transactions, in parallel, on multi-core CPUs. We separate the execution of transactions between the primary and secondary replicas. The primary replica executes transactions on multiple CPU cores and creates a dependency graph of the transactions that the backup replicas utilize to execute transactions in parallel.Open Acces
Acelerador de hardware em FPGA para inferência em redes neurais artificiais
A era da informção traz uma série de novas demandas: aumento no poder computacional bruto, computação ubíqua e inteligência artificial são alguns exemplos. A melhoria de desempenho é alcançada por meio de otimizações de hardware para problemas específicos. E nesse sentido que o presente trabalho visa construir um acelerador de hardware para o algoritmo de inferência em redes neurais artificiais. A arquitetura é customizável em parâmetros como número de núcleos de processamento, onde variáveis de customização podem ser facilmente modificados em tempo de síntese alterando os parâmetros definidos com uso da linguagem de descrição de hardware SystemVerilog. O acelerador possui memórias internas que possibilitam salvar pesos sinápticos, entradas, saídas e dimensões das camadas das rede que podem ser escritas por um dispositivo mapeado de memória. As funções de ativação podem ser escolhidas dentre
três implementadas em hardware e quatro por aproximação linear em LUT, que podem
ser programadas em tempo de execuçãoo. O design possui três estágios de pipeline e data forwarding. A arquitetura foi submetida a testes de simulação e acurácia em comparação com um modelo padrão e foi verificada com métricas de cobertura de código. Uma análise sobre a performance em ciclos de clock e frequência máxima para uma tecnologia de referência tamb´em foram disponibilizadas. O trabalho termina com sugestões de melhorias não executadas, em especial para implementação do algoritmo de treinamento por gradiente descendente, com poucas modificações na arquitetura
Extension of the Control Concept for a Mobile Overhead Manipulator to Whole-Body Impedance Control
At present, robots constitute a central component of contemporary factories. The application of traditional ground-based systems, however, may lead to congested floors with minimal space left for new robots or human workers. Overhead manipulators, on the other hand, aim to occupy the unutilized ceiling space, in order to manipulate the workspace located below them. The SwarmRail system is an example of such an overhead manipulator. This concept deploys mobile units driving across a passive railstructure above the ground. Additionally, equipping the mobile units with robotic arms at their bottom side enables this design to provide continuous overhead manipulation while in motion. Although a first demonstrator confirmed the functional capability of said system, the current hardware suffers from complications while traversing rail crossings. Due to uneven rails consecutive rails, said crossing points cause the robot's wheels to collide with the new rail segment it is driving towards. Additionally, the robot experiences an undesired sudden altitude change.
In this thesis, we aim to implement a hierarchical whole-body impedance tracking controller for the robots employed within the SwarmRail system. Our controller combines a kinematically controlled mobile unit with the impedance-based control of a robotic arm through an admittance interface. The focus of this thesis is set on the controller's robustness against the previously mentioned external disturbances. The performance of this controller is validated inside a simulation that incorporates the aforementioned complications. Our findings suggest, that the control strategy presented in this thesis provides a foundation for the development of a controller applicable to the physical demonstrator
Provincialising whiteness: Òyìnbó and the politics of race in Lagos, Nigeria
Much academic work on racialisation processes to date has focused on a geographically restricted range of racial regimes characterised by white supremacy. This study broadens the geographical scope of analyses by looking at race-making practices in Lagos, Nigeria. I explore the geographical specificity of race-making in Lagos through interrogation of the concept of òyìnbó – a Yorùbá word most often translated into English as ‘white person.’ By highlighting the particular meanings attached to òyìnbó, and the political work that racialisation does in this understudied context, I argue for the need to provincialise understandings of whiteness in studies of global race-making processes. The project is based upon eleven months of ethnographic fieldwork with Lagosians of different generations and social demographics at three different research sites: a senior secondary school, the University of Lagos, and at a church. My findings suggest that divergent meanings are attached to òyìnbós in these contexts, which do not universally celebrate whiteness. Rather, the practice of race-making in Lagos predominantly addresses local political concerns, and common attributes associated with òyìnbós are primarily evaluated according to local people’s own moral economy. This results in highly ambivalent attitudes to òyìnbós as individuals and to òyìnbó as trope. I suggest that these attitudes can best be explained by situating constructions of òyìnbós within their wider social context in Lagos. By centring local understandings in this way, I argue that the political practice of race-making in Lagos is not purely a reflection of a singular, global racial hierarchy, but a means of actively engaging with global and local power structures. I propose that seeking to understand the emic nature of divergent global race-making processes in this way has the potential to broaden academic understanding of these and related social phenomena
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