9,810 research outputs found

    Evaluating Digital Libraries: A Longitudinal and Multifaceted View

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    Conceptual design study for an advanced cab and visual system, volume 2

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    The performance, design, construction and testing requirements are defined for developing an advanced cab and visual system. The rotorcraft system integration simulator is composed of the advanced cab and visual system and the rotorcraft system motion generator, and is part of an existing simulation facility. User's applications for the simulator include rotorcraft design development, product improvement, threat assessment, and accident investigation

    Enhancing the Impact of Cross-Sector Partnerships. Four Impact Loops for Channeling Partnership Studies

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    This paper addresses the topic of this special symposium issue: how to enhance the impact of cross-sector partnerships. The paper takes stock of two related discussions: the discourse in cross-sector partnership research on how to assess impact and the discourse in impact assessment research on how to deal with more complex organizations and projects. We argue that there is growing need and recognition for cross-fertilization between the two areas. Cross-sector partnerships are reaching a paradigmatic status in society, but both research and practice need more thorough evidence of their impacts and of the conditions under which these impacts can be enhanced. This paper develops a framework that should enable a constructive interchange between the two research areas, while also framing existing research into more precise categories that can lead to knowledge accumulation. We address the preconditions for such a framework and discuss how the constituent parts of this framework interact. We distinguish four different pathways or impact loops that refer to four distinct orders of impact. The paper concludes by applying these insights to the four papers included in this special issue

    Deep Underground Science and Engineering Laboratory - Preliminary Design Report

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    The DUSEL Project has produced the Preliminary Design of the Deep Underground Science and Engineering Laboratory (DUSEL) at the rehabilitated former Homestake mine in South Dakota. The Facility design calls for, on the surface, two new buildings - one a visitor and education center, the other an experiment assembly hall - and multiple repurposed existing buildings. To support underground research activities, the design includes two laboratory modules and additional spaces at a level 4,850 feet underground for physics, biology, engineering, and Earth science experiments. On the same level, the design includes a Department of Energy-shepherded Large Cavity supporting the Long Baseline Neutrino Experiment. At the 7,400-feet level, the design incorporates one laboratory module and additional spaces for physics and Earth science efforts. With input from some 25 science and engineering collaborations, the Project has designed critical experimental space and infrastructure needs, including space for a suite of multidisciplinary experiments in a laboratory whose projected life span is at least 30 years. From these experiments, a critical suite of experiments is outlined, whose construction will be funded along with the facility. The Facility design permits expansion and evolution, as may be driven by future science requirements, and enables participation by other agencies. The design leverages South Dakota's substantial investment in facility infrastructure, risk retirement, and operation of its Sanford Laboratory at Homestake. The Project is planning education and outreach programs, and has initiated efforts to establish regional partnerships with underserved populations - regional American Indian and rural populations

    The SIMPSONS project: An integrated Mars transportation system

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    In response to the Request for Proposal (RFP) for an integrated transportation system network for an advanced Martian base, Frontier Transportation Systems (FTS) presents the results of the SIMPSONS project (Systems Integration for Mars Planetary Surface Operations Networks). The following topics are included: the project background, vehicle design, future work, conclusions, management status, and cost breakdown. The project focuses solely on the surface-to-surface transportation at an advanced Martian base

    Comparative Genomics of Microbial Chemoreceptor Sequence, Structure, and Function

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    Microbial chemotaxis receptors (chemoreceptors) are complex proteins that sense the external environment and signal for flagella-mediated motility, serving as the GPS of the cell. In order to sense a myriad of physicochemical signals and adapt to diverse environmental niches, sensory regions of chemoreceptors are frenetically duplicated, mutated, or lost. Conversely, the chemoreceptor signaling region is a highly conserved protein domain. Extreme conservation of this domain is necessary because it determines very specific helical secondary, tertiary, and quaternary structures of the protein while simultaneously choreographing a network of interactions with the adaptor protein CheW and the histidine kinase CheA. This dichotomous nature has split the chemoreceptor community into two major camps, studying either an organism’s sensory capabilities and physiology or the molecular signal transduction mechanism. Fortunately, the current vast wealth of sequencing data has enabled comparative study of chemoreceptors. Comparative genomics can serve as a bridge between these communities, connecting sequence, structure, and function through comprehensive studies on scales ranging from minute and molecular to global and ecological. Herein are four works in which comparative genomics illuminates unanswered questions across the broad chemoreceptor landscape. First, we used evolutionary histories to refine chemoreceptor interactions in Thermotoga maritima, pairing phylogenetics with x-ray crystallography. Next, we uncovered the origin of a unique chemoreceptor, isolated only from hypervirulent strains of Campylobacter jejuni, by comparing chemoreceptor signaling and sensory regions from Campylobacter and Helicobacter. We then selected the opportunistic human pathogen Pseudomonas aeruginosa to address the question of assigning multiple chemoreceptors to multiple chemotaxis pathways within the same organism. We assigned all P. aeruginosa receptors to pathways using a novel in silico approach by incorporating sequence information spanning the entire taxonomic order Pseudomonadales and beyond. Finally, we surveyed the chemotaxis systems of all environmental, commensal, laboratory, and pathogenic strains of the ubiquitous Escherichia coli, where we discovered an ancestral chemoreceptor gene loss event that may have predisposed a well-studied subpopulation to adopt extra-intestinal pathogenic lifestyles. Overall, comparative genomics is a cutting edge method for comprehensive chemoreceptor study that is poised to promote synergy within and expand the significance of the chemoreceptor field

    RoboCrane: a system for providing a power and a communication link between lunar surface and lunar caves for exploring robots

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    Lava caves are the result of a geological process related to the cooling of basaltic lava flows. On the Moon, this process may lead to caves several kilometers long and diameters of hundreds of meters. Access to lava tubes can be granted through skylights, a vertical pit between the lava tube and the lunar surface. This represents an outstanding opportunity for long-term missions, for future permanent human settlements, and for accessing pristine samples of lava, secondary minerals and volatiles. Given this, the ESA launched a campaign through the Open Space Innovation Platform calling for ideas that would tackle the many challenges of exploring lava pits. Five projects, including Robocrane, were selected. Solar light and direct line of sight (for communications) with the lunar surface are not available inside lava tubes. This is a problem for any robot (or swarm of robots) exploring the lava tubes. Robocrane tackles both problems by deploying an element (called the Charging head, or CH) at the bottom of the skylight by means of a crane. This CH behaves as a battery charger and a communication relay for the exploring robots. The required energy is extracted from the crane’s solar panel (on the surface) and driven to the bottom of the skylight through an electrical wire running in parallel to the crane hoisting wire. Using a crane allows the system to deal with unstable terrain around the skylight rim and protect the wires from abrasion from the rocky surface and the pit rim. The charger in the CH is wireless so that the charging process can begin as soon as any of the robots get close enough to the CH. This avoids complex and time-consuming docking operations, aggravated by the skylight floor orography. The crane infrastructure can also be used to deploy the exploring robots inside the pit, reducing their design constraints and mass budget, as the robots do not need to implement their own self-deployment system. Finally, RoboCrane includes all the sensors and actuators for remote operation from a ground station. RoboCrane has been designed in a parametric tool so it can be dynamically and rapidly adjusted to input-variable changes, such as the number of exploring robots, their electrical characteristics, and crane reach, etc.Agencia Estatal de Investigación | Ref. RTI2018-099682-A-I0

    Improving the skills of forest harvester operators

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    Forestry suffers from a shortage of trained machine operators, which jeopardises efficient and productive operations. Extensive training is required to skilfully master the complex tasks of operators of forest harvesters and forest forwarders. Therefore, the digitisation of the industry envisages training and support systems on machines that provide real-time support to operators, both on-site and remotely. The aim of this thesis was to improve training methods and pave the way for the development of future operator support systems, therefore a detailed analysis of harvester operators' work tasks, focussing on motor control skills and cognitive (work)load, was conducted. The work was guided by the following two general research questions, which were systematically answered throughout the studies presented in this thesis. (1) How can training methods for robotic arm operators be improved by analysing performance limiting factors in the bimanual control of the robotic cranes and (2) How can the machine operators be effectively supported with different sensorimotor support systems to ensure high level performance? To this end, a multi-pronged approach using qualitative and quantitative methods was adopted and five scientific studies were carried out. For three quantitative laboratory studies, a multi-joint robotic manipulator was designed and programmed as a simulation environment, which in its basic layout resembles the crane of real forestry machines. To identify the challenges in learning the motor control of such robotic cranes, this work focussed on the joystick control of the individual joints (joint control) or the movement of the tip (end-effector) of the robotic crane. Two experimental studies on the acquisition of operating skills with the two different control schemes, showed that in spite of a gain in mental workload reduction with end-effector control, movement accuracy remains difficult with both control schemes. This refers with joint control to the challenging use of the joints involved in the fine control of the robotic crane and with end-effector control to a general lack of accuracy. In a third study, visual and auditory (sonification) support systems were implemented in the simulation environment and compared for increasing accuracy. Auditory support systems showed higher effectiveness, which depends on initial operator performance level. In summary, this thesis has shown that behavioural analysis at the level of joystick movements and the analysis of crane movements can be very fruitful for studying the development of human control skills and deriving new performance indicators that can be used in operator training and the design of different operator support systems. The development of machines with increasing technical operator support will potentially lead to new challenges in real-world operation, where the management of cognitive workload and the detrimental effects, specifically of cognitive underload conditions, will require a rethinking and design of the operators’ work
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