1,343 research outputs found

    Investigation of Seal-to-Floor Effects on Semi-Span Transonic Models

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    In an effort to achieve the maximum possible Reynolds number (Re) when conducting production testing for flight loads aerodynamic databases, it has been the preferred practice of The Boeing Company / Commercial Airplanes (BCA) -- Loads and Dynamics Group since the early 1990's to test large scale semi-span models in the 11- By 11-Foot Transonic Wind Tunnel (TWT) leg of the Unitary Plan Wind Tunnel (UPWT) at the NASA Ames Research Center (ARC). There are many problems related to testing large scale semi-span models of high aspect ratio flexible transport wings, such as; floor boundary layer effects, wing spanwise wall effects, solid blockage buoyancy effects, floor mechanical interference effects, airflow under the model effects, or tunnel flow gradient effects. For most of these issues, BCA has developed and implemented either standard testing methods or numerical correction schemes and these will not be discussed in this document. Other researchers have reported on semi-span transonic testing correction issues, however most of the reported research has been for low Mach testing. Some of the reports for low Mach testing address the difficult problem of preventing undesirable airflow under a semi-span model while ensuring unrestricted main balance functionality, however, for transonic models this issue has gone unresolved. BCA has been cognizant for sometime that there are marked differences in wing pressure distributions from semi-span transonic model testing than from full model or flight testing. It has been suspected that these differences are at least in part due to airflow under the model. Previous efforts by BCA to address this issue have proven to be ineffective or inconclusive and in one situation resulted in broken hardware. This paper reports on a Boeing-NASA collaborative investigation based on a series of small tests conducted between June 2006 and November 2007 in the 11 by 11 foot Transonic Wind Tunnel at NASA Ames on three large commercial jet transport configurations to assess the effects of sealing a semi-span model to the floor and to investigate efficient sealing and testing techniques. This document will show how sealing the model to the floor has a small but remarkably far reaching spanwise effect on wing pressures, wing local section forces and wing force summations

    Beyond Rigor and Relevance Towards Responsibility and Reverberation: Information Systems Research That Really Matters

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    This paper is an outcome of a panel discussion that was held during the 2005 International Conference on Information Systems (ICIS). The panel, titled, IS Research that Really Matters: Beyond the IS Rigor - Relevance Debate, was organized to foster a discussion on conducting IS research that is significant, in terms of impact, and responsible to the needs of stakeholders. To this end, panel members were asked to push the debate on IS research beyond the traditional arguments of rigor and relevance in research towards IS research that reverberates and is responsible. In doing so, the panel members shared their views on the definition of significant research, who are the stakeholders of IS research and what are their needs, and how do we move the field ahead

    Social Activism in Information Systems Research: Making the World a Better Place

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    This paper reports on a panel held during the 2006 International Conference on Information Systems (ICIS). The panel titled, Social Activism in IS Research: Making the World a Better Place, was organized to question whether and how Information System (IS) research is making tangible impacts to our society. More specifically, each panelist was asked to address: (1) How can IS research, and researchers, make contributions to underdeveloped societies and underserved communities?; and (2) How can IS researchers learn from the particularities of these communities to inform better research, teaching, and service? While each panel member had different perspectives to offer in relation to these two questions, all agreed that IS academe needs to raise its awareness and efforts considerably with a view to address the needs of underserved communities

    Social Activism in IS Research: Making the World a Better Place

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    Information Systems (IS) can play a salient role in the transformation of our societies, especially in less-developed (or under-served) communities. IS can be used to benefit citizens in these societies through improvements in education, government, healthcare, social, and entrepreneurial systems. It would be a mistake to think that under-served communities can develop without optimal deployment of IS, after all advanced societies depended on IS to boost their development. The realization that IS offers potential benefit to improve the livelihood of the less-privileged is not new or recent. However, what is not clear is what should be the role of IS researchers in addressing the needs of the under-served communities

    Investigating the physical properties of transiting hot Jupiters with the 1.5-m Kuiper Telescope

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    We present new photometric data of 11 hot Jupiter transiting exoplanets (CoRoT-12b, HAT-P-5b, HAT-P-12b, HAT-P-33b, HAT-P-37b, WASP-2b, WASP-24b, WASP-60b, WASP-80b, WASP-103b, XO-3b) in order to update their planetary parameters and to constrain information about their atmospheres. These observations of CoRoT-12b, HAT-P-37b and WASP-60b are the first follow-up data since their discovery. Additionally, the first near-UV transits of WASP-80b and WASP-103b are presented. We compare the results of our analysis with previous work to search for transit timing variations (TTVs) and a wavelength dependence in the transit depth. TTVs may be evidence of a third body in the system and variations in planetary radius with wavelength can help constrain the properties of the exoplanet's atmosphere. For WASP-103b and XO-3b, we find a possible variation in the transit depths that may be evidence of scattering in their atmospheres. The B-band transit depth of HAT-P-37b is found to be smaller than its near-IR transit depth and such a variation may indicate TiO/VO absorption. These variations are detected from 2-4.6σ\sigma, so follow-up observations are needed to confirm these results. Additionally, a flat spectrum across optical wavelengths is found for 5 of the planets (HAT-P-5b, HAT-P-12b, WASP-2b, WASP-24b, WASP-80b), suggestive that clouds may be present in their atmospheres. We calculate a refined orbital period and ephemeris for all the targets, which will help with future observations. No TTVs are seen in our analysis with the exception of WASP-80b and follow-up observations are needed to confirm this possible detection.Comment: 18 pages, 7 figures, 9 Tables. Light Curves available online. Accepted to MNRAS (2017 August 25

    Toward a Decision Support System for Mitigating Urban Heat

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    With the continuous rise of global urbanization, city planners and policymakers are increasingly concerned with urban heat islands (UHI), which are metropolitan areas that are significantly warmer than their surrounding rural areas. We address the United Nation’s Sustainable Development Goal 11 “Sustainable Cities and Communities,” and we design and develop a decision support system (DSS), which will help city planners and policymakers to overcome economic barriers to reach environmental sustainability goals

    Vorticity Induced by a Moving Elliptic Belt

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    The viscous flow inside an elliptic moving belt is studied using Newton's method on a Hermite collocation approximation. The streamlines and especially the vorticity distribution are found for Reynolds number up to 1000 and aspect ratio up to five. For low Reynolds numbers vorticity diffuses from regions of high curvature. For high Reynolds numbers there exists a closed boundary layer and a core of constant vorticity. The core vorticity compares well with the estimation from the mean square law

    Collaboration between Science and Religious Education teachers in Scottish Secondary schools

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    The article reports on quantitative research that examines: (1) the current practice in collaboration; and (2) potential for collaboration between Science and Religious Education teachers in a large sample of Scottish secondary schools. The authors adopt and adapt three models (conflict; concordat and consonance) to interrogate the relationship between science and religion (and the perceived relation between these two subjects in schools) (Astley and Francis 2010). The findings indicate that there is evidence of limited collaboration and, in a few cases, a dismissive attitude towards collaboration (conflict and concordat and very weak consonance). There is, however, evidence of a genuine aspiration for greater collaboration among many teachers (moving towards a more robust consonance model). The article concludes by discussing a number of key factors that must be realised for this greater collaboration to be enacted

    AI ATAC 1: An Evaluation of Prominent Commercial Malware Detectors

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    This work presents an evaluation of six prominent commercial endpoint malware detectors, a network malware detector, and a file-conviction algorithm from a cyber technology vendor. The evaluation was administered as the first of the Artificial Intelligence Applications to Autonomous Cybersecurity (AI ATAC) prize challenges, funded by / completed in service of the US Navy. The experiment employed 100K files (50/50% benign/malicious) with a stratified distribution of file types, including ~1K zero-day program executables (increasing experiment size two orders of magnitude over previous work). We present an evaluation process of delivering a file to a fresh virtual machine donning the detection technology, waiting 90s to allow static detection, then executing the file and waiting another period for dynamic detection; this allows greater fidelity in the observational data than previous experiments, in particular, resource and time-to-detection statistics. To execute all 800K trials (100K files ×\times 8 tools), a software framework is designed to choreographed the experiment into a completely automated, time-synced, and reproducible workflow with substantial parallelization. A cost-benefit model was configured to integrate the tools' recall, precision, time to detection, and resource requirements into a single comparable quantity by simulating costs of use. This provides a ranking methodology for cyber competitions and a lens through which to reason about the varied statistical viewpoints of the results. These statistical and cost-model results provide insights on state of commercial malware detection
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