3,593 research outputs found
Studies on the dynamics of chaotic multi-wavelet reentrant propagation using a hybrid cellular automaton model of excitable tissue
There is a compelling body of evidence implicating continuous propagation (reentry) sustained by multiple meandering wavelets in the pathology of advanced human atrial fibrillation (AF). This forms the basis for many current therapies such as the Cox MAZE procedure and its derivatives, which aim to create non-conducting lesions in order to "transect" these circuits before they form. Nevertheless, our ability to successfully treat persistent and permanent AF using catheter ablation remains inadequate due to current limitations of clinical mapping technology as well as an incomplete understanding of how to place lesions in order to maximize circuit transection and, more importantly, minimize AF burden. Here, we used a hybrid cellular automaton model to study the dynamics of chaotic, multi-wavelet reentry (MWR) in excitable tissue. First, we used reentry as an exemplar to investigate a hysteretic disease mechanism in a multistable nonlinear system. We found that certain interactions with the environment can cause persistent changes to system behavior without altering its structure or properties, thus leading to a disconnect between clinical symptoms and the underlying state of disease. Second, we developed a novel analytical method to characterize the spatiotemporal dynamics of MWR. We identified a heterogeneous spatial distribution of reentrant pathways that correlated with the spatial distribution of cell activation frequencies. Third, we investigated the impact of topological and geometrical substrate alterations on the dynamics of MWR. We demonstrated a multi-phasic relationship between obstacle size and the fate of individual episodes. Notably, for a narrow range of sizes, obstacles appeared to play an active role in rapidly converting MWR to stable structural reentry. Our studies indicate that reentrant-pathway distributions are non-uniform in heterogeneous media (such as the atrial myocardium) and suggest a clinically measurable correlate for identifying regions of high circuit density, supporting the feasibility of patient-specific targeted ablation. Moreover, we have elucidated the key mechanisms of interaction between focal obstacles and MWR, which has implications for the use of spot ablation to treat AF as some recent studies have suggested
Transfusion research priorities for blood services in sub-Saharan Africa
Evidence to support many blood transfusion policies and practices in sub-Saharan Africa (SSA) is weak or lacking. SSA cannot extrapolate from wealthy countriesâ research findings because its environment, users and structures are very different and SSA has critical blood shortages. SSA needs to generate its own evidence but research funds are very scarce and need to be carefully targeted to match need. This study aimed to define this need by determining research priorities for blood services in SSA. Thirty-five stakeholders representing diverse blood servicesâ interests and expertise participated in a workshop. An adapted âconsensus development methodâ was used to identify, agree and justify research priorities under five themes through small group and plenary discussion, and cumulative voting. Research priorities covered traditional research areas, such as clinical use of blood and infection screening, but also highlighted many new, under-researched topics, mostly concerning blood service âsystemsâ, such as economics, blood components and regulation. Lack of electronic information management systems was an important hindrance to the blood servicesâ ability to generate robust research data. This study has identified and prioritised novel research that will help blood services in SSA to address their own needs including their most urgent problem: the lack of access to adequate blood supplies. To catalyse this research blood services in SSA need to enhance their capacity to conduct, commission and manage research and to strengthen their collaborations within and beyond Africa
Beyond data in the smart city:learning from a case study of re-purposing existing campus IoT
In this article we present a case study of our experiences of using existing IoT infrastructure to create a campus scale âliving laboratoryâ for promoting energy savings and environmental sustainability. As a series of lessons for others creating IoT systems from existing city infrastructures we offer the challenges we have experienced through our attempt to join up and re-purpose existing energy monitoring and building management systems as an IoT infrastructure for a âsmart campusâ. We highlight the limitations of particular views of a campus from a purely data-driven perspective, advocating data- aware over data-driven approaches that engage with a wide variety of stakeholders. Finally, we reflect on the inclusion of peopleâs practices in understanding and designing smart cities, repurposing existing IoT, more careful consideration of ethics and domestication when co-creating smart campuses and the importance of challenging the existing rhetoric around energy waste in Smart Cities and Smart buildings research
The limits of HCD:reimagining the anthropocentricity of ISO 9241-210
Human-centred design (HCD) is just that: human-centred. As we approach the limits of Earth's biophysical systems, it no longer feels appropriate to place humans at the centre of design decisions. Yet HCD and its ISOâISO-9241-210:2010âcontinue to be powerful and popular tools within many computing and design departments, as well as in their affiliated industries. These design approaches are perpetuating the trend of incremental improvements to the living standards of the already privileged and digitally connected whilst ignoring the broader environmental and socio-political effects of digital technologies. In this paper, we attempt to reimagine HCD and its ISO by drawing on fields and concepts such as sustainable interaction design (SID), animal-computer interaction (ACI), and object oriented ontology (OOO). Through this, we contribute a preliminary set of proposals about what needs to change with HCD and its ISO. We close by discussing the ISO development process and suggesting routes for environmentally concerned researchers to influence the evolution of HCD's ISO
The limits of HCD : reimagining the anthropocentricity of ISO 9241-210
Human-centred design (HCD) is just that: human-centred. As we approach the limits of Earth's biophysical systems, it no longer feels appropriate to place humans at the centre of design decisions. Yet HCD and its ISOâISO-9241-210:2010âcontinue to be powerful and popular tools within many computing and design departments, as well as in their affiliated industries. These design approaches are perpetuating the trend of incremental improvements to the living standards of the already privileged and digitally connected whilst ignoring the broader environmental and socio-political effects of digital technologies. In this paper, we attempt to reimagine HCD and its ISO by drawing on fields and concepts such as sustainable interaction design (SID), animal-computer interaction (ACI), and object oriented ontology (OOO). Through this, we contribute a preliminary set of proposals about what needs to change with HCD and its ISO. We close by discussing the ISO development process and suggesting routes for environmentally concerned researchers to influence the evolution of HCD's ISO
Are people the key to enabling collaborative smart logistics?
The number of parcels delivered is growing annually, with a 15.7% increase to 1 billion parcel deliveries in the UK in 2015. We introduce Freight Traffic Control 2050 which is exploring how to transform last-mile urban freight through âcollaborative logisticsâ. Based on our ethnographic fieldwork, we introduce the context and challenges in this domain. We highlight the value of experience and tacit knowledge, and the importance of approaching this domain from a socio-technical perspective. We offer a selection of early challenges identified as a starting point for discussion within the HCI community
The future of techno-disruption in gig economy workforces: challenging the dialogue with fictional abstracts
In this article we explore near-future of the pervasive computing, AI, and HCI in the context of the disruptive potential of technologies on workers in the on-demand gig economy. Using fictional abstracts, the authors muse on dystopian case studies of: independent contractors, last-mile couriers, teachers, and creative professionals. This article serves as base for critical reflections on: 1) the need for multidisciplinary approaches when tackling broader and far-reaching societal implications of digital technology in the gig economy, and 2) the potential role of fictional abstracts in the design process of future digital technologies
Sharing & Cooperativism:Designing For Economies
Recent work on sharing and cooperativism has helped widen our understanding of the emerging systems for exchanges, interactions, and relationships beyond mainstream economic models, in particu- lar through studying local cooperatives and their sharing practices across various domains. These efforts also indicate that design has the potential to shape our engagements with the global political economy. However, so far, there are few design resources tailored for exploring and further developing design insights from empirical and conceptual research on sharing and cooperativism. Therefore, we invite the community to discuss the role of design in relation to economies of sharing and cooperativism. In this workshop, we will gather a diverse group of scholars, designers, and activists to think together how designs for sustainable economies can be created and circulated across cooperatives and platforms, with the aim to springboard social and economic aspects of sharing cultures
The Limits of Evaluating Sustainability
Designing technology with sustainability in mind is becoming more and more important, especially considering future scenarios of limited resources where the worldâs current lifestyle of wasteful consumption needs to change. But how can researchers believably argue that their solutions are indeed sustainable? How can consumers and technology users reliably acquire, understand, and apply information about environmental sustainability? Those questions are difficult to answer, especially in research domains where the impact on sustainability is not immediately measurable, such as sustainable HCI. The evaluation of sustainability is an ongoing problem that is often glossed over, but we believe the community needs to intensify its efforts to articulate its evaluation methods to other disciplines and external stakeholders. Even if those disciplines and stakeholders understand the importance of designing for sustainability, we need convincing arguments â such as validation through thorough evaluations â to showcase why a specific design solution works in the real world. In this paper, we analyze this problem by highlighting examples of sustainable HCI research in which evaluation of sustainability failed. We also look at previous research that sought to address this issue and discuss how their solutions can be generalized â and when they might fail. While we do not have the final answer, our intention is to start a discussion as to why sustainable HCI research is oftentimes not doing enough to justify the validity of its solutions. We close our paper by suggesting a few examples of what we believe to be potential ways to address those issues and take action to improve the evaluation of sustainability
Towards an holistic view of the energy and environmental impacts of domestic media and IT
To date, research in sustainable HCI has dealt with eco-feedback, usage and recycling of appliances within the home, and longevity of portable electronics such as mobile phones. However, there seems to be less awareness of the energy and greenhouse emissions impacts of domestic consumer electronics and information technology. Such awareness is needed to inform HCI sustainability researchers on how best to prioritise efforts around digital media and IT. Grounded in inventories, interview and plug energy data from 33 undergraduate student participants, our findings provide the context for assessing approaches to reducing the energy and carbon emissions of media and IT in the home. In the paper, we use the findings to discuss and inform more fruitful directions that sustainable HCI research might take, and we quantify how various strategies might have modified the energy and emissions impacts for our participants
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