945 research outputs found

    Ed Bradley\u27s Message To the \u2782 Graduates

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    Challenges for Developing Complex System Governance

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    This paper examines the challenges and practice implications for Complex System Governance (CSG). CSG is presented as an emerging field focused on the design, execution, and evolution of the higher order (metasystem) functions necessary to provide control, communication, coordination, and integration of a complex system. This paper is focused on three primary objectives. First, we introduce the complex system problem domain that the CSG field is being designed to address. The pervasiveness of this problem domain is demonstrated by a short examination of the water utilities sector. Second, we expound the nature of CSG and an emerging reference model that defines the functions of CSG. These functions must be performed by any system that maintains viability (continued existence). The CSG reference model rests on the underlying conceptual foundations built from Systems Theory (axioms and propositions governing system integration and coordination) and Management Cybernetics (communication and control for effective system organization). Third, we explore the particular challenges that must be addressed if the potential of the emerging CSG field is to be realized. The paper concludes by suggesting the potential that the CSG field brings for enhancing practitioner capabilities to more effectively deal with complex systems and their associated problems

    RFI Risk Reduction Activities Using New Goddard Digital Radiometry Capabilities

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    The Goddard Radio-Frequency Explorer (GREX) is the latest fast-sampling radiometer digital back-end processor that will be used for radiometry and radio-frequency interference (RFI) surveying at Goddard Space Flight Center. The system is compact and deployable, with a mass of about 40 kilograms. It is intended to be flown on aircraft. GREX is compatible with almost any aircraft, including P-3, twin otter, C-23, C-130, G3, and G5 types. At a minimum, the system can function as a clone of the Soil Moisture Active Passive (SMAP) ground-based development unit [1], or can be a completely independent system that is interfaced to any radiometer, provided that frequency shifting to GREX's intermediate frequency is performed prior to sampling. If the radiometer RF is less than 200MHz, then the band can be sampled and acquired directly by the system. A key feature of GREX is its ability to simultaneously sample two polarization channels simultaneously at up to 400MSPS, 14-bit resolution each. The sampled signals can be recorded continuously to a 23 TB solid-state RAID storage array. Data captures can be analyzed offline using the supercomputing facilities at Goddard Space Flight Center. In addition, various Field Programmable Gate Array (FPGA) - amenable radiometer signal processing and RFI detection algorithms can be implemented directly on the GREX system because it includes a high-capacity Xilinx Virtex-5 FPGA prototyping system that is user customizable

    Current Topics in Children's Learning and Cognition

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    Learning in Cognitive Niches / Gerhardt, Ana Flávia Lopes Magela -- Using the Dynamics of a Person-Context System to Describe Children’s Understanding of Air Pressure / Steen, Steffie Van der; Steenbeek, Henderien; Geert, Paul Van -- Preschoolers Learning Science: Myth or Reality? / Kloos, Heidi; Baker, Heather; Luken, Eleanor; Brown, Rhonda; Pfeiffer, David; Carr, Victoria -- The Emergence of Scientific Reasoning / Morris, Bradley J.; Croker, Steve; Masnick, Amy M.; Zimmerman, Corinne -- Cognition and the Child Witness : Understanding the Impact of Cognitive Development in Forensic Contexts / Segovia, Daisy A.; Crossman, Angela M. -- Beyond the Black-and-White of Autism : How Cognitive Performance Varies with Context / Amaral, Joseph L.; Collins, Susan; Bohache, Kevin T.; Kloos, Heidi -- Psychological Fitness in Young Adult Video Game Players / Pokorski, Mieczyslaw; Borecki, Lukasz; Jernajczyk, Urszula -- The Impact of Moving Away from Home on Undergraduate Metacognitive Development / Downing, KevinAs a whole, the essays in this book address theoretical and empirical issues related to children's learning and cognition. The first essay, titled Learning in Cognitive Niches, treats the process of sense making on a theoretical level, discussing the complexity of factors that give rise to children's learning. It is followed by an essay, titled Using the Dynamics of a Person-Context System to Describe Children's Understanding of Air Pressure, that applies ideas from complexity science and dynamics-systems theory to children's learning about science. The next four essays summarize and synthesize already published findings, in an effort to go beyond individual viewpoints and present a more nuanced picture of children's sense making. In particular, two of these summaries, Preschoolers Learning Science: Myth or Reality? and The Emergence of Scientific Reasoning, focus on children's ability to make sense of their physical environment. The essay Cognition and the Child Witness: Understanding the Impact of Cognitive Development in Forensic Contexts seeks to shed light on children's sense making relevant to forensic issues. And the essay Beyond the Black-and-White of Autism: How Cognitive Performance Varies with Context ventures in the area of autism, a disorder that demonstrates atypical processes of combining pieces of information. The final two essays provide original data to add to the discussion of what factors affect cognitive functioning. In particular, the essay Cognitive Fitness in Young Adult Video Game Players seeks to re-assess the often-assumed relation between video gaming and various aspects of thinking, memory, intelligence, and visual-spatial abilities. And the essay Impact of Moving Away from Home on Undergraduate Metacognitive Development explicitly connects life circumstances to the ability to monitor and control one's thinking. Together, the collection of essays are a further step towards understanding the process of sense making as children and young adults interact with their environment

    Multiwaveband analysis of brightest GRB070125

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    We present a comprehensive multiwavelength analysis of the bright, long duration gamma-ray burst GRB 070125, comprised of observations in gamma-ray, X-ray, optical, millimeter and centimeter wavebands. Radio light curves show rapid flux variations, which are interpreted as due to interstellar scintillation, and are used to derive an upper limit of 2.4×10^17 cm on the radius of the fireball. Radio light curves and spectra suggest that the afterglow shock wave is moving in a dense medium. Our broadband modeling favors a constant density profile for the circumburst medium over a wind-like profile (R^−2). GRB 070125 is a burst with high radiative efficiency (>60%)

    Magnetic moment of welded HTS samples: dependence on the current flowing through the welds

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    We present a method to calculate the magnetic moments of the high-temperature superconducting (HTS) samples which consist of a few welded HTS parts. The approach is generalized for the samples of various geometrical shapes and an arbitrary number of welds. The obtained relations between the sample moment and the density of critical current, which flows through the welds, allow to use the magnetization loops for a quantitative characterization of the weld quality in a wide range of temperatures and/or magnetic fields.Comment: RevTeX4, 4 pages, 2 figures. Submitted to Supercond. Sci. Techno

    The IPAC Image Subtraction and Discovery Pipeline for the intermediate Palomar Transient Factory

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    We describe the near real-time transient-source discovery engine for the intermediate Palomar Transient Factory (iPTF), currently in operations at the Infrared Processing and Analysis Center (IPAC), Caltech. We coin this system the IPAC/iPTF Discovery Engine (or IDE). We review the algorithms used for PSF-matching, image subtraction, detection, photometry, and machine-learned (ML) vetting of extracted transient candidates. We also review the performance of our ML classifier. For a limiting signal-to-noise ratio of 4 in relatively unconfused regions, "bogus" candidates from processing artifacts and imperfect image subtractions outnumber real transients by ~ 10:1. This can be considerably higher for image data with inaccurate astrometric and/or PSF-matching solutions. Despite this occasionally high contamination rate, the ML classifier is able to identify real transients with an efficiency (or completeness) of ~ 97% for a maximum tolerable false-positive rate of 1% when classifying raw candidates. All subtraction-image metrics, source features, ML probability-based real-bogus scores, contextual metadata from other surveys, and possible associations with known Solar System objects are stored in a relational database for retrieval by the various science working groups. We review our efforts in mitigating false-positives and our experience in optimizing the overall system in response to the multitude of science projects underway with iPTF.Comment: 66 pages, 21 figures, 7 tables, accepted by PAS

    Gray Wolves and Livestock in Montana: A Recent History of Damage Management

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    The Montana gray wolf (Canis lupus) population grew from 2 wolves in 1979 to a minimum of 316 by late 2006. Resolving conflicts, both perceived and real, between wolves and livestock became a dominant social issue for the federal recovery program, and it remains so today. The United States Fish and Wildlife Service and now Montana Fish, Wildlife & Parks work with United States Department of Agriculture, Animal Plant Health Inspection Service, Wildlife Services to reduce depredation risks and address wolf-related conflicts through a combination of non-lethal and lethal management tools. The number of wolf complaints investigated from 1987-2006 increased as the population increased and expanded its distribution into Montana after reintroduction into Yellowstone National Park and central Idaho during 1995 and 1996. Montana wolf packs routinely encountered livestock, though wolf depredation was a relatively rare cause of livestock death and difficult to predict or prevent. Cattle and sheep were killed most often from March to October, although losses were confirmed each month. From 1987 to 2006, wolves killed 230 cattle and 436 sheep. However, confirmed losses probably represent a fraction of actual wolf losses. Few other types of livestock classes were killed. Conflicts are addressed on a case-by-case basis, striving to connect the agency response to the damage in space and time and to decrease the potential for future losses. Lethal control is implemented incrementally after predation was verified, and 254 wolves were killed from 1987 to 2006. Only complete removal of either wolves or livestock eliminates the potential for wolf depredation. The continued presence of a viable wolf population requires that a wide variety of non-lethal and lethal tools be investigated and implemented. That combination will also be required to maintain local public tolerance of wolves where the two overlap and to foster broad public acceptance of techniques used to minimize conflicts. Resolving wolf and livestock conflicts at a local scale is but one component of a larger state wolf conservation and management program. When wolves are delisted, regulated public harvest will allow us to more proactively manage the population
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