6,913 research outputs found

    The Andrew W. Mellon Foundation Art Museum Staff Demographic Survey

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    The Andrew W. Mellon Foundation, in partnership with the Association of Art Museum Directors (AAMD) and the American Alliance of Museums (AAM), has announced the results of the first comprehensive survey to assess the ethnic and gender diversity of the staffs of art museums across the United States. Undertaken to replace anecdotal evidence with hard data, the survey provides the museum field with the first statistical baseline against which progress can be measured. Art Museum Staff Demographic SurveyAmong its chief findings, the survey documented a significant movement toward gender equality in art museums. Women now comprise some 60 percent of museum staffs, with a preponderance of women in the curatorial, conservation and education roles that can be a pipeline toward leadership positions. The survey found no such pipeline toward leadership among staff from historically underrepresented minorities. Although 28 percent of museum staffs are from minority backgrounds, the great majority of these workers are concentrated in security, facilities, finance, and human resources jobs. Among museum curators, conservators, educators and leaders, only 4 percent are African American and 3 percent Hispanic

    An introduction to the Princeton sailwing windmill

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    Specifically discussed is the sailwing windmill. The aerodynamic characteristics of the sailwing itself are presented in condensed form and its natural application to the wind machine is discussed. Past and present sailwing windmill configurations are shown and their relative merits are compared. A section on a future promising configuration is presented and its compatibility to advanced technology electrical machinery is briefly discussed. Also included is a short bibliography

    Profiling user activities with minimal traffic traces

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    Understanding user behavior is essential to personalize and enrich a user's online experience. While there are significant benefits to be accrued from the pursuit of personalized services based on a fine-grained behavioral analysis, care must be taken to address user privacy concerns. In this paper, we consider the use of web traces with truncated URLs - each URL is trimmed to only contain the web domain - for this purpose. While such truncation removes the fine-grained sensitive information, it also strips the data of many features that are crucial to the profiling of user activity. We show how to overcome the severe handicap of lack of crucial features for the purpose of filtering out the URLs representing a user activity from the noisy network traffic trace (including advertisement, spam, analytics, webscripts) with high accuracy. This activity profiling with truncated URLs enables the network operators to provide personalized services while mitigating privacy concerns by storing and sharing only truncated traffic traces. In order to offset the accuracy loss due to truncation, our statistical methodology leverages specialized features extracted from a group of consecutive URLs that represent a micro user action like web click, chat reply, etc., which we call bursts. These bursts, in turn, are detected by a novel algorithm which is based on our observed characteristics of the inter-arrival time of HTTP records. We present an extensive experimental evaluation on a real dataset of mobile web traces, consisting of more than 130 million records, representing the browsing activities of 10,000 users over a period of 30 days. Our results show that the proposed methodology achieves around 90% accuracy in segregating URLs representing user activities from non-representative URLs

    Analysing long-term interactions between demand response and different electricity markets using a stochastic market equilibrium model. ESRI WP585, February 2018

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    Power systems based on renewable energy sources (RES) are characterised by increasingly distributed, volatile and uncertain supply leading to growing requirements for flexibility. In this paper, we explore the role of demand response (DR) as a source of flexibility that is considered to become increasingly important in future. The majority of research in this context has focussed on the operation of power systems in energy only markets, mostly using deterministic optimisation models. In contrast, we explore the impact of DR on generator investments and profits from different markets, on costs for different consumers from different markets, and on CO2 emissions under consideration of the uncertainties associated with the RES generation. We also analyse the effect of the presence of a feed-in premium (FIP) for RES generation on these impacts. We therefore develop a novel stochastic mixed complementarity model in this paper that considers both operational and investment decisions, that considers interactions between an energy market, a capacity market and a feed-in premium and that takes into account the stochasticity of electricity generation by RES. We use a Benders decomposition algorithm to reduce the computational expenses of the model and apply the model to a case study based on the future Irish power system. We find that DR particularly increases renewable generator profits. While DR may reduce consumer costs from the energy market, these savings may be (over)compensated by increasing costs from the capacity market and the feed-in premium. This result highlights the importance of considering such interactions between different markets

    Gamma rays of 0.3 to 30 MeV from PSR 0531+21

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    Pulsed gamma rays from the Crab Pulsar PSR 0531+21 are reported for energies of 0.3 to 30 MeV. The observations were carried out with the UCR gamma ray double Compton scatter telescope launched on a balloon from Palestine, Texas at 4.5 GV, at 2200 LT, September 29, 1978. Two 8 hr observations of the pulsar were made, the first starting at 0700 UT (0200 LT) September 30 just after reaching float altitude of 4.5 g/sq cm. Analysis of the total gamma ray flux from the Crab Nebula plus pulsar using telescope vertical cell pairs was published previously. The results presented supersede the preliminary ones. The double scatter mode of the UCR telescope measures the energy of each incident gamma ray from 1 to 30 MeV and its incident angle to a ring on the sky. The time of arrival is measured to 0.05 ms. The direction of the source is obtained from overlapping rings on the sky. The count rate of the first scatter above a threshold of 0.3 MeV is recorded every 5.12 ms. The Crab Pulsar parameters were determined from six topocentric arrival times of optical pulses

    Pulpit Diagrams: With Brief Notes of Explanation

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    https://digitalcommons.acu.edu/crs_books/1058/thumbnail.jp

    Measured performance of the new University of California gamma ray telescope

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    The design of the new medium energy balloon-borne gamma ray telescope is discussed. This telescope is sensitive to 1-30 MeV gamma rays. The results of the initial calibration are described. The position and energy resolutions of 32 plastic and NaI(Tl) scintillator bars, each 100 cm long are discussed. The telescope's measured angular and energy resolutions as a function of incident angle are compared with detailed Monte Carlo calculations at 1.37, 2.75 and 6.13 MeV. The expected resolutions are 5 deg FHWM and 8% at 2.75 MeV. The expected area-efficiency is 250 cm
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