992,644 research outputs found

    A File System Abstraction for Sense and Respond Systems

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    The heterogeneity and resource constraints of sense-and-respond systems pose significant challenges to system and application development. In this paper, we present a flexible, intuitive file system abstraction for organizing and managing sense-and-respond systems based on the Plan 9 design principles. A key feature of this abstraction is the ability to support multiple views of the system via filesystem namespaces. Constructed logical views present an application-specific representation of the network, thus enabling high-level programming of the network. Concurrently, structural views of the network enable resource-efficient planning and execution of tasks. We present and motivate the design using several examples, outline research challenges and our research plan to address them, and describe the current state of implementation.Comment: 6 pages, 3 figures Workshop on End-to-End, Sense-and-Respond Systems, Applications, and Services In conjunction with MobiSys '0

    The Impact of Sense and Respond Systems

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    Sense and respond (S&R) systems based on information technology amplify one of the most fundamental characteristics of life — the ability to detect and respond to events. Living things thrive when they respond effectively to what’s going on in their environments. A zebra that doesn’t run away from a hungry lion dies and one that runs away unnecessarily wears out. Organizations sense and respond collectively: lions in a pride signal each other when they hunt; societies deal with crises by harnessing capabilities of governments, charities, and individuals. When our ancestors hunted millennia ago, they saw as far as the eye could see and threw spears as far as their muscles let them. Today, S&R systems let us detect events far out in space and respond anywhere on the globe. By 2020, S&R systems will become an integral part of the activities of people and organizations around the world whether they’re rich or poor, in farming or medicine, at work or at play

    'Sense and respond' and 'autonomic' logistics: a review of US and UK developments

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    Until recently, platform-based, logistics applications required data to be physically downloaded and transferred between systems so that analysis could estimate the status of key components. In both the Sense and Respond Logistics (S&RL) and Autonomic Logistics (AL) systems, prognostics have been added to monitoring functions, effectively extending the reach of Combat Service Support (CSS). The scope the supply chain has also been expanded with the potential inclusion of some classes of supply within the AL approach. The real time and predictive aspects are relatively new logistics developments facilitated by the real-time communication of data while platforms are in operation. While the (Australian) Military Integrated Logistics Information System (MILIS) proposes to extend the reach of supply chain information to sub-unit level, it falls short of crossing the gap to link Health and Usage Monitoring System (HUMS), platform-based, data into the logistics continuum to provide end-to-end visibility, a foxhole-to-factory-to-foxhole perspective, of the supply chain. This paper will review developments in recent military applications of Autonomic Logistics and Sense & Respond Logistics in the United States Defense Forces and the military in the UK while also considering a selection of Australian Defence Force programs. It will state the case for application of Autonomic Logistics and Sense & Respond Logistics to the ASLAV and Bushmaster platforms, in a similar fashion to those employed in the US and the UK, as a source of accurate and up-to-date CSS information for the various levels of command

    Artificial Rheotaxis

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    Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on develop- ing artificial systems that can mimic microorganisms, and in particular their self-propulsion. Here, we report on the design and characterization of syn- thetic self-propelled particles that migrate upstream, known as positive rheo- taxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model no- tably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step towards the realization of biomimetic micro-systems withthe ability to sense and respond to environmental changesComment: Published in Science Advances [Open access journal of Science Magazine

    Control systems for WRASPA.

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    The paper discusses the need for a wave energy converter (WEC) to sense and respond to its environment in order to survive and to produce its maximum useful output. Such systems are described for Wraspa, a WEC being developed at Lancaster University and first reported at ICCEP in 2007. The main control system that continually monitors and optimises the power-take-off is termed ldquoStepwise Controlrdquo and seeks to continually adjust the damping force applied to the collector to suit the wave force that drives it. The complete instrumentation and control system that will be needed is considered briefly, including the above PTO control system; direction sensing and heading control; tide level compensation; condition monitoring and provisions for access and maintenance

    Spotting Agreement and Disagreement: A Survey of Nonverbal Audiovisual Cues and Tools

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    While detecting and interpreting temporal patterns of non–verbal behavioral cues in a given context is a natural and often unconscious process for humans, it remains a rather difficult task for computer systems. Nevertheless, it is an important one to achieve if the goal is to realise a naturalistic communication between humans and machines. Machines that are able to sense social attitudes like agreement and disagreement and respond to them in a meaningful way are likely to be welcomed by users due to the more natural, efficient and human–centered interaction they are bound to experience. This paper surveys the nonverbal cues that could be present during agreement and disagreement behavioural displays and lists a number of tools that could be useful in detecting them, as well as a few publicly available databases that could be used to train these tools for analysis of spontaneous, audiovisual instances of agreement and disagreement

    Self-propulsion of a catalytically active particle near a planar wall: from reflection to sliding and hovering

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    Micron-sized particles moving through solution in response to self-generated chemical gradients serve as model systems for studying active matter. Their far-reaching potential applications will require the particles to sense and respond to their local environment in a robust manner. The self-generated hydrodynamic and chemical fields, which induce particle motion, probe and are modified by that very environment, including confining boundaries. Focusing on a catalytically active Janus particle as a paradigmatic example, we predict that near a hard planar wall such a particle exhibits several scenarios of motion: reflection from the wall, motion at a steady-state orientation and height above the wall, or motionless, steady "hovering." Concerning the steady states, the height and the orientation are determined both by the proportion of catalyst coverage and the interactions of the solutes with the different "faces" of the particle. Accordingly, we propose that a desired behavior can be selected by tuning these parameters via a judicious design of the particle surface chemistry
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