577 research outputs found

    Clayton Act Quantity Limit Proceedings

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    Towards 3D joint inversion of full tensor gravity, magnetotelluric and seismic refraction data

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    EGU2010-4184-2 Joint inversion of different datasets is emerging as an important tool to enhance resolution and decrease inversion artifacts in structurally complex areas. Performing the inversion in 3D allows us to investigate such complex structures but requires computationally efficient forward modeling and inversion methods. Furthermore we should be able to flexibly change inversion parameters, coupling approaches and forward modeling schemes in order to find a suitable approach for the given target. We present a 3D joint inversion framework for scalar and full tensor gravity, magnetotelluric and seismic data that allows us to investigate different approaches. It consists of two memory efficient gradient based optimization techniques, L-BFGS and NLCG, and optimized parallel forward solvers for the different datasets. In addition it provides the necessary flexibility in terms of model parametrization and coupling method by completely separating the inversion parameters and geometry from the parametrization of the individual method. This separation allows us to easily switch between completely different types of parameterizations and use structural coupling as well as coupling based on parameter relationships for the joint inversion. First tests on synthetic data with a fixed parameter relationship coupling show promising results and demonstrate that 3D joint inversion is becoming feasible for realistic size models

    Human Factors Guidelines for Remotely Piloted Aircraft System (RPAS) Remote Pilot Stations (RPS)

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    This document contains a list of human factors guidelines for remote pilot stations (RPS) arranged within an organizing structure. The guidelines are intended for the remote pilot stations (RPSs) of remotely piloted aircraft (RPA) that are capable of operating beyond visual line-of-sight in all airspace classes of the United States National Airspace System (NAS). Numerous human factors guidelines and standards for technological systems have been published by standards agencies and regulatory authorities. In compiling this document, the intent was not to reproduce or re-state existing human factors material. Instead, this document focuses on the unique issues of civilian RPAS, and contains guidelines specific to this sector. As a result, it should be seen as a supplement to existing aviation human factors standards and guidance material. Two constraints were used to focus the scope of this document. First, the assumptions contained in the FAA (2013a) UAS roadmap were used to define the responsibilities that will be assigned to the pilot of a RPAS operating beyond visual line-of-sight in the NAS. This in turn, helped to define the tasks that the remote pilot must perform via the RPS, and thereby the required features and characteristics of the RPS. Second, the points of difference between RPAS and conventional aviation were used to further focus the guidelines on the considerations that make piloting a RPA significantly different to piloting a conventional aircraft. Five broad categories of guidelines are identified. These are (1) performance-based descriptions of pilot tasks that must be accomplished via the RPS, (2) information content of displays, (3) descriptions of control inputs, (4) properties of the interface, and (5) high-level design considerations. Some of the guidelines in this document have been adapted from existing RPAS human factors material from several sources, including RTCA publications and Standardization Agreements (STANAGs) published by the North Atlantic Treaty Organization (NATO)

    Passing the Baton: An Experimental Study of Shift Handover

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    Shift handovers occur in many safety-critical environments, including aviation maintenance, medicine, air traffic control, and mission control for space shuttle and space station operations. Shift handovers are associated with increased risk of communication failures and human error. In dynamic industries, errors and accidents occur disproportionately after shift handover. Typical shift handovers involve transferring information from an outgoing shift to an incoming shift via written logs, or in some cases, face-to-face briefings. The current study explores the possibility of improving written communication with the support modalities of audio and video recordings, as well as face-to-face briefings. Fifty participants participated in an experimental task which mimicked some of the critical challenges involved in transferring information between shifts in industrial settings. All three support modalities, face-to-face, video, and audio recordings, reduced task errors significantly over written communication alone. The support modality most preferred by participants was face-to-face communication; the least preferred was written communication alone

    Bags of sand and dirt : exploiting the British Geological Survey's environmental samples and database

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    Ask any member of the public or even the science community what samples they would expect to find in a geological survey organisation and they would undoubtedly list fossils, rocks and minerals, the traditional view of a geological collection. Few would think about the tons of sediment, soil, and water samples – environmental samples less glamorously referred to as bags of sand and dirt. This is hardly moon or gold dust yet collectively these samples are a valuable asset for the British Geological Survey (BGS) that require collating in a systematic and secure manner. The corporate BGS Geochemical Database contains some half-a-million samples and eight million analyte determinations. This Oracle database contains numerous tables describing the samples, the sites from where they were collected, details about the laboratories that have carried out analyses and the methods used, in addition to chemical analyses. It is an under-used environmental resource that contains BGS geochemical data gathered over a period of nearly 40 years. Bringing this collection of digital environmental data from disparate projects together into one database has required procedures to be developed to ensure consistent coding for the description of samples. The chemical data has to be verified as being fit for purpose through data conditioning to ensure a consistency of quality. The environmental data is increasingly being used for legislative purposes, for example the identification of contaminated land under the Environment Protection Act Part IIa. The data therefore has to be presented in a way that non-scientists can understand what it shows and, equally as important, what are the quality issues and limits associated with the data

    The Coming Paradigm-Shift in Maintenance: From Metals to Composites

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    The purpose of this study is to examine the current maintenance practices of airline operators in the detection and repair of damage to composite structures, with the aim of learning lessons that will be applicable to the maintenance of future advanced composite airplanes. A process map was created to capture the events and activities that occur from the moment a damage event occurs, through damage detection, assessment and repair. The study is identifying areas where operational risks may negatively impact the process, where personnel are required to make judgments in the absence of procedural guidance, and areas where future tools or techniques may be of assistance

    Human Factor Challenges of Remotely Piloted Aircraft

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    The control stations of many unmanned systems have been characterized by inadequate human-system interfaces. Some of the interface problems may have been prevented had an existing regulation or cockpit design principle been applied. In other cases, the design problems may indicate a lack of suitable guidance material. The human factors of unmanned operations will be reviewed, and a NASA program to develop human-factor guidelines for control stations will be described. To be effective, guidelines must be relevant to a wide range of systems, must not be overly prescriptive, and must not impose premature standardization on evolving technologies. Several types of guidelines are described. These relate to required capabilities, information requirements, properties of the human machine interface, and general cognitive engineering principles

    Human Factors Guidelines for UAS in the National Airspace System

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    The ground control stations (GCS) of some UAS have been characterized by less-than-adequate human-system interfaces. In some cases this may reflect a failure to apply an existing regulation or human factors standard. In other cases, the problem may indicate a lack of suitable guidance material. NASA is leading a community effort to develop recommendations for human factors guidelines for GCS to support routine beyond-line-of-sight UAS operations in the national airspace system (NAS). In contrast to regulations, guidelines are not mandatory requirements. However, by encapsulating solutions to identified problems or areas of risk, guidelines can provide assistance to system developers, users and regulatory agencies. To be effective, guidelines must be relevant to a wide range of systems, must not be overly prescriptive, and must not impose premature standardization on evolving technologies. By assuming that a pilot will be responsible for each UAS operating in the NAS, and that the aircraft will be required to operate in a manner comparable to conventionally piloted aircraft, it is possible to identify a generic set of pilot tasks and the information, control and communication requirements needed to support these tasks. Areas where guidelines will be useful can then be identified, utilizing information from simulations, operational experience and the human factors literature. In developing guidelines, we recognize that existing regulatory and guidance material will, at times, provide adequate coverage of an area. In other cases suitable guidelines may be found in existing military or industry human factors standards. In cases where appropriate existing standards cannot be identified, original guidelines will be proposed

    Human errors in context : a study of unsafe acts in aircraft maintenance /

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    The Climate Crisis A Toolkit and Resource Pack for Funders in South Africa. Why, How and the Role of Philanthropy

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    The Toolkit has its genesis in a three-part webinar series on Future Proofing Philanthropy in South Africa Against Climate Change, which was run by IPASA. This series of engagements demonstrated that key reasons for inaction on climate change by philanthropic funders include the difficulties in understanding the issue, applying it to their strategic thinking, and in finding effective solutions. The webinar series culminated in the development of the Toolkit, which is aimed at helping funders overcome these challenges. The Toolkit provides a range of useful, accessible, and carefully curated resources to support your journey in understanding the climate crisis and how philanthropy can respond. Our hope is that this Toolkit will catalyse new thinking and will be the beginning of a South African climate philanthropy community of practice and movement. The toolkit contains rich information and practical advice for organisations on every stage of their climate journey
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