61 research outputs found

    Cellular Probabilistic Automata - A Novel Method for Uncertainty Propagation

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    We propose a novel density based numerical method for uncertainty propagation under certain partial differential equation dynamics. The main idea is to translate them into objects that we call cellular probabilistic automata and to evolve the latter. The translation is achieved by state discretization as in set oriented numerics and the use of the locality concept from cellular automata theory. We develop the method at the example of initial value uncertainties under deterministic dynamics and prove a consistency result. As an application we discuss arsenate transportation and adsorption in drinking water pipes and compare our results to Monte Carlo computations

    Autonomous Dry Stone: On-Site Planning and Assembly of Stone Walls with a Robotic Excavator

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    On-site robotic construction not only has the potential to enable architectural assemblies that exceed the size and complexity practical with laboratory-based prefabrication methods, but also offers the opportunity to leverage context-specific, locally sourced materials that are inexpensive, abundant, and low in embodied energy. We introduce a process for constructing dry stone walls in situ, facilitated by a customized autonomous hydraulic excavator. Cabin-mounted LiDAR sensors provide for terrain mapping, stone localization and digitization, and a planning algorithm determines the placement position of each stone. As the properties of the materials are unknown at the beginning of construction, and because error propagation can hinder the efficacy of pre-planned assemblies with non-uniform components, the structure is planned on-the-fly: the desired position of each stone is computed immediately before it is placed, and any settling or unexpected deviations are accounted for. We present the first result of this geometric- and motion-planning process: a 3-m-tall wall composed of 40 stones with an average weight of 760 kg.ISSN:2509-8780ISSN:2509-811

    Intracerebral endotheliitis and microbleeds are neuropathological features of COVID‐19

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    Coronavirus disease 19 (COVID-19), caused by infection with the severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2), has become a worldwide pandemic (1). Symptoms of COVID-19 vary widely and range from asymptomatic disease to severe pneumonia and multiorgan failure (2). A severe disease course is more likely in older patients and patients with pre-existing respiratory and cardiovascular conditions (2). Patients with severe Sars-CoV-2 infection may present with ischaemic stroke (3, 4) or even fatal intracerebral haemorrhage (5). To date, little is known about the neuropathological sequelae of COVID-19. The largest published autopsy series of COVID-19 neuropathology reported microthrombi and acute haemorrhagic infarction in a significant number of patients (6), while another more recent study found evidence of lymphocytic encephalitis and meningitis (7). Endotheliitis of the brain and extraneural organs has been shown in Sars-CoV infected patients (8). Similarly, it is a recurrent feature in the lungs and other peripheral organs of Sars-CoV-2 infected patients (9) but has not yet been reported in the central nervous system. We speculated that cerebrovascular pathology in COVID-19 patients could be a direct consequence of hitherto unidentified cerebral endotheliitis caused by Sars-CoV-2

    Robotic Landscapes—Designing the Unfinished

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    Robotic earthmoving equipment is dramatically changing the way landscapes can be formed and maintained. Landscapes evolve through constantly changing conditions, and a dynamic response to natural environments can never be considered final. Autonomous systems can enable this adaptive and continuous transformation of terrain instead of simply creating predefined and static earthworks. Robotic Landscapes—Designing the Unfinished opens up insights into landscape design’s evolving culture by proposing a new equilibrium between natural and mechanical forces. Reflecting on a series of design research experiments on granular materials at the department of architecture at ETH Zurich, this book is designed to demonstrate the importance of successive design iterations in framing, forming, and finding. Each page reveals computational procedures where functional terrain structures emerge, each capable of sustaining a dynamic landscape that is forever changing
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