4,275 research outputs found

    Combining Computational Fluid Dynamics and Agent-Based Modeling: A New Approach to Evacuation Planning

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    We introduce a novel hybrid of two fields—Computational Fluid Dynamics (CFD) and Agent-Based Modeling (ABM)—as a powerful new technique for urban evacuation planning. CFD is a predominant technique for modeling airborne transport of contaminants, while ABM is a powerful approach for modeling social dynamics in populations of adaptive individuals. The hybrid CFD-ABM method is capable of simulating how large, spatially-distributed populations might respond to a physically realistic contaminant plume. We demonstrate the overall feasibility of CFD-ABM evacuation design, using the case of a hypothetical aerosol release in Los Angeles to explore potential effectiveness of various policy regimes. We conclude by arguing that this new approach can be powerfully applied to arbitrary population centers, offering an unprecedented preparedness and catastrophic event response tool

    Cognition as Embodied Morphological Computation

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    Cognitive science is considered to be the study of mind (consciousness and thought) and intelligence in humans. Under such definition variety of unsolved/unsolvable problems appear. This article argues for a broad understanding of cognition based on empirical results from i.a. natural sciences, self-organization, artificial intelligence and artificial life, network science and neuroscience, that apart from the high level mental activities in humans, includes sub-symbolic and sub-conscious processes, such as emotions, recognizes cognition in other living beings as well as extended and distributed/social cognition. The new idea of cognition as complex multiscale phenomenon evolved in living organisms based on bodily structures that process information, linking cognitivists and EEEE (embodied, embedded, enactive, extended) cognition approaches with the idea of morphological computation (info-computational self-organisation) in cognizing agents, emerging in evolution through interactions of a (living/cognizing) agent with the environment

    Discussing prognosis and end-of-life care in the final year of life: A randomized controlled trial of a nurse-led ommunication support programme for patients and caregivers

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    Introduction: Timely communication about lifeexpectancy and end-of-life care is crucial forensuring good patient quality-of-life at the end of lifeand a good quality of death. This article describes theprotocol for a multisite randomised controlled trial of anurse-led communication support programme tofacilitate patients' and caregivers' efforts tocommunicate about these issues with theirhealthcare team.Methods and analysis: This NHMRC-sponsored trialis being conducted at medical oncology clinics locatedat/affiliated with major teaching hospitals in Sydney,Australia. Patients with advanced, incurable cancer andlife expectancy of less than 12 months will participatetogether with their primary informal caregiver wherepossible. Guided by the self-determination theory ofhealth-behaviour change, the communication supportprogramme pairs a purpose-designed Question PromptList (QPL-an evidence-based list of questionspatients/caregivers can ask clinicians) with nurse-ledexploration of QPL content, communication challenges,patient values and concerns and the value of earlydiscussion of end-of-life issues. Oncologists are alsocued to endorse patient and caregiver question askingand use of the QPL. Behavioural and self-report datawill be collected from patients/caregivers approximatelyquarterly for up to 2.5 years or until patient death, afterwhich patient medical records will be examined.Analyses will examine the impact of the intervention onpatients' and caregivers' participation in medicalconsultations, their self-efficacy in medical encounters,quality-of-life, end-of-life care receipt and quality-ofdeathindicators.Ethics and dissemination: Approvals have beengranted by the human ethics review committee ofRoyal Prince Alfred Hospital and governance officersat each participating site. Results will be reported inpeer-reviewed publications and conferencepresentations.Trial registration number: Australian New ZealandClinical Trials Registry ACTRN12610000724077

    Agent cognition through micro-simulations: Adaptive and tunable intelligence with NetLogo LevelSpace

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    We present a method of endowing agents in an agent-based model (ABM) with sophisticated cognitive capabilities and a naturally tunable level of intelligence. Often, ABMs use random behavior or greedy algorithms for maximizing objectives (such as a predator always chasing after the closest prey). However, random behavior is too simplistic in many circumstances and greedy algorithms, as well as classic AI planning techniques, can be brittle in the context of the unpredictable and emergent situations in which agents may find themselves. Our method, called agent-centric Monte Carlo cognition (ACMCC), centers around using a separate agent-based model to represent the agents' cognition. This model is then used by the agents in the primary model to predict the outcomes of their actions, and thus guide their behavior. To that end, we have implemented our method in the NetLogo agent-based modeling platform, using the recently released LevelSpace extension, which we developed to allow NetLogo models to interact with other NetLogo models. As an illustrative example, we extend the Wolf Sheep Predation model (included with NetLogo) by using ACMCC to guide animal behavior, and analyze the impact on agent performance and model dynamics. We find that ACMCC provides a reliable and understandable method of controlling agent intelligence, and has a large impact on agent performance and model dynamics even at low settings.Comment: Model source code available here: https://github.com/qiemem/Wolf-Sheep-Predation-Micro-Sims, In: Unifying Themes in Complex Systems IX. ICCS 2018. Springer Proceedings in Complexity. Springer, Cha

    Recovery after single-breath halothane induction of anaesthesia in daycase patients

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    A single-breath technique of inhalational induction of anaesthesia allows intravenous induction agents to be avoided. We have investigated recovery from anaesthesia in 40 daycase patients, using tests of psychomotor function. Patients anaesthetised with inhalational induction awaken earlier than those who receive thiopentone, but not significantly earlier. There were no significant differences in postoperative psychomotor function between patients who received thiopentone and those who had inhalational inductions. Single-breath halothane, nitrous-oxide, oxygen induction is an alternative to intravenous induction in cooperative adults, but does not confer significant benefits in terms of recovery.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75757/1/j.1365-2044.1988.tb06685.x.pd

    Probing the Neutron Star Interior with Glitches

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    With the aim of constraining the structural properties of neutron stars and the equation of state of dense matter, we study sudden spin-ups, glitches, occurring in the Vela pulsar and in six other pulsars. We present evidence that glitches represent a self-regulating instability for which the star prepares over a waiting time. The angular momentum requirements of glitches in Vela indicate that at least 1.4% of the star's moment of inertia drives these events. If glitches originate in the liquid of the inner crust, Vela's `radiation radius' R∞R_\infty must exceed ~12 km for a mass of 1.4 solar masses. The isolated neutron star RX J18563-3754 is a promising candidate for a definitive radius measurement, and offers to further our understanding of dense matter and the origin of glitches.Comment: Invited talk at the Pacific Rim Conference on Stellar Astrophysics, Hong Kong, Aug. 1999. 9 pages, 5 figure

    A Universal Model of Global Civil Unrest

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    Civil unrest is a powerful form of collective human dynamics, which has led to major transitions of societies in modern history. The study of collective human dynamics, including collective aggression, has been the focus of much discussion in the context of modeling and identification of universal patterns of behavior. In contrast, the possibility that civil unrest activities, across countries and over long time periods, are governed by universal mechanisms has not been explored. Here, we analyze records of civil unrest of 170 countries during the period 1919-2008. We demonstrate that the distributions of the number of unrest events per year are robustly reproduced by a nonlinear, spatially extended dynamical model, which reflects the spread of civil disorder between geographic regions connected through social and communication networks. The results also expose the similarity between global social instability and the dynamics of natural hazards and epidemics.Comment: 8 pages, 3 figure

    Patient perspectives regarding communication about prognosis and end-of-life issues: How can it be optimised?

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    Objective: To explore patients' perspectives across two cultures (Australia and USA) regarding communication about prognosis and end-of-life care issues and to consider the ways in which these discussions can be optimised. Methods: Fifteen Australian and 11 US patients completed individual semi-structured qualitative interviews. A further 8 US patients participated in a focus group. Interviews and focus group recordings were transcribed verbatim and interpreted using thematic text analysis with an inductive, data-driven approach. Results: Global themes identified included readiness for and outcomes of discussions of prognosis and end-of-life issues. Contributing to readiness were sub themes including patients' adjustment to and acceptance of their condition (together with seven factors promoting this), doctor and patient communication skills, mutual understandings and therapeutic relationship elements. Outcomes included sub themes of achievement of control and ability to move on. A model of the relationships between these factors, emergent cross cultural differences, and how factors may help to optimise these discussions are presented. Conclusion: Identified optimising factors illustrate Australian and US patients' perspectives regarding how prognosis and end-of-life issues can be discussed with minimised negative impact. Practice implications: Recognition of factors promoting adjustment, acceptance and readiness and use of the communication skills and therapeutic relationship elements identified may assist in optimising discussions and help patients plan care, achieve more control of their situation and enjoy an optimal quality-of-life. © 2011 Elsevier Ireland Ltd
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