10,209 research outputs found

    An Analysis of the Knowledge and Skill Levels Required to Effectively Support Analytical Cost Decisions in Source Selections

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    We analyze these three factors (education, experience, and training) in an effort to identify the knowledge and skills necessary for cost analysts to possess to be effective members of cost panel evaluation teams during source selections. This research effort assesses whether the cost panel members and senior Air Force acquisition military and civilian personnel associate the levels of education, experience, and training as being key factors in fulfilling cost analysts duties while supporting the selection of a source in the government procurement process. To accomplish this objective, a literature review, personal interviews, and questionnaires were utilized. Descriptive statistics and hypothesis testing were conducted to evaluate the responses. The recommendations of this study are intended to assist cost analysts in attaining the knowledge and skills necessary in contributing and supporting a cost panel a during source selection

    The Impact of Nuclear Reaction Rate Uncertainties on Evolutionary Studies of the Nova Outburst

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    The observable consequences of a nova outburst depend sensitively on the details of the thermonuclear runaway which initiates the outburst. One of the more important sources of uncertainty is the nuclear reaction data used as input for the evolutionary calculations. A recent paper by Starrfield, Truran, Wiescher, & Sparks (1998) has demonstrated that changes in the reaction rate library used within a nova simulation have significant effects, not just on the production of individual isotopes (which can change by an order of magnitude), but on global observables such as the peak luminosity and the amount of mass ejected. We present preliminary results of systematic analyses of the impact of reaction rate uncertainties on nova nucleosynthesis.Comment: 4 pages, 3 figures. to appear in "Cosmic Explosions", proceeding of the 10th Annual October Astrophysics Conference in Maryland (ed. S.S. Holt and W. W. Zhang

    Strategic Effects of Conflict with Iraq: Southeast Asia

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    The author has been asked to analyze four issues: the position that key states in their region are taking on U.S. military action against Iraq; the role of America in the region after the war with Iraq; the nature of security partnerships in the region after the war with Iraq; and the effect that war with Iraq will have on the war on terrorism in the region.https://press.armywarcollege.edu/monographs/1797/thumbnail.jp

    Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean

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    The central theme of this project has been the diagnosis of blocking anticyclogenesis and the corresponding interactions with synoptic-scale circulations. To that end an extensive investigation of the dynamics and energetics of a major blocking anticyclone and two upstream cyclones, all of which occurred over the North Atlantic Ocean and the United States in January 1979, was undertaken. Data for the study were provided by Goddard Laboratory for Atmospheres (GLA) 4 LAT by 5 LON FGGE analyses. The methodology has primarily focused on the diagnosis of circulation forcing mechanisms using the modified forms (referred to as the extended forms) of the height tendency and Zwack-Okossi equations developed by our research group. Calculations use routine second-order finite differencing with boundary layer fraction and sensible heating and latent heat release represented as parameterized quantities. Of particular interest are the latent heat release estimates, which combine convectional parameterized values with estimates derived from satellite IR data. The latter were obtained using an algorithm derived by Dr. Franklin R. Robertson of NASA's Marshall Space Flight Center. Results are contained in project reports, theses and publications identified in previous review summaries and reports, and publications listed at the end of this summary. Significant accomplishments in the past year are presented

    Multilevel Analysis of Trachomatous Trichiasis and Corneal Opacity in Nigeria : The Role of Environmental and Climatic Risk Factors on the Distribution of Disease.

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    Funding: Jennifer L Smith was supported by the International Trachoma Initiative through a grant from the Bill and Melinda Gates Foundation. Anthony Solomon is a Wellcome Trust Intermediate Clinical Fellow (098521). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean

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    One segment of work in the past year focused on the diagnosis of a major blocking anticyclone and its interacting synoptic scale circulations that occurred during January 1979 over the North Atlantic Ocean. Another segment focused on the diagnosis of a second explosive cyclone development that occurred over the southeastern United States during the time of block formation. The diagnoses were accomplished using the diagnostic relationship known as the Zwack-Okossi (Z-O) development equation. Results indicate that in both cyclone cases the development occurred as a result of the favorable influence of positive vorticity advection, warm air advection, and latent heat release and ceased when one or more of these influences diminished. The advantages of the Z-O equation are described

    Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean

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    Work was completed on the height tendency diagnoses of two extratropical cyclones that occurred upstream from the blocking event studied previously. One developed explosively over water 60 to 36 hours before the block first appeared, while the second developed explosively over the southeastern United States during the time of block formation. In both cases, both vorticity and temperature advection were consistently important forcing mechanisms. This is in contrast to the block itself, in which vorticity advection was easily the dominant forcing mechanism. Latent heat release was also significant, accounting for about 50 percent of the total height falls in the cyclone below 850 mb. Estimates of latent heat release were greatly enhanced by coupling parameterized estimates with values derived from GOES IR data using an algorithm developed by Marshall's F. R. Robertson. Among the difficulties encountered in this work was the identification of an appropriate lower boundary condition for the solution of the height tendency equation. The zero value currently used tends to yield underestimates of the lower troposphere height tendencies. To address this problem a new diagnostic technique was developed in cooperation with Dr. Peter Zwack of the University of Quebec at Montreal. Based on an equation Dr. Zwack had previously developed (the Zwack-Okossi development equation), researchers now have a relationship that is completely consistent with the height tendency equation and provides estimates of lower boundary geostrophic vorticity or height tendencies. Finally, comparison of the SAT (satellite data) and NOSAT (no satellite data) analyses is progressing well. The present focus is on both the new diagnostic technique and the SAT/NOSAT comparisons. The former is being tested on the southeastern United States cyclone case previously mentioned and compared with the height tendency diagnoses already completed. The latter are being examined for the blocking case described in the publications cited in this summary. In addition to obtaining statistics that will allow general comparison of the two analyses, it will be possible to determine whether conclusions about the dynamics of the block development are influenced by the analysis set used

    A diagnosis of the development of a winter anticyclone over North America

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    This paper examines the 48-h life cycle of a winter anticyclone occurring over North America from 18 to 20 January 1979 using Goddard Laboratory for Atmospheres FGGE level 3b (SOP 1) global analyses on a 4 deg latitude by 5 deg longitude grid. Applying the relatively new methodology of the Zwack-Okossi equation, results show that anticyclonic vorticity advection and cold-air advection acted to develop the anticyclone, while adiabatic warming in the descending air opposed development. Other forcing processes made only small contributions to anticyclone changes. Vertical profiles of the development quantities reveal that vorticity and temperature advections, as well as the adiabatic warming, maximized in the 200-300-mb layer

    Multicast Delivery of IPTV Over the Internet

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    Television represents one of the greatadvancements in information delivery. Traditionally, televisionservice has been delivered using dedicated communicationmethods such as terrestrial and satellite based wirelesstransmissions and fixed cable based transmissions. Some of thesedelivery mechanisms have advanced and now provide servicesincluding voice and Internet access. Another communicationmethod, traditional telephone service, has greatly improvedand expanded to deliver services such as television and Internetaccess.This convergence of service provides cost savings, allowingproviders to utilize existing communication networks to deliveradditional services to its customers, often at minimal or zeroinfrastructure cost. One disadvantage of this method is customerreach is still limited to those with access to dedicated serviceprovider networks. The ability to disengage television servicefrom these dedicated networks and move it to a more ubiquitousnetwork would greatly improve the customer reach of theproviders.The most obvious network choice for a delivery mediumis the Internet. Given that television delivery mechanisms havealready started the progression towards IPTV, the service isa natural fit. One issue hindering this transition is bandwidthavailability. In private delivery networks, the issue of bandwidthavailability for IPTV is often combated through the use of IPMulticasting. Considering the Internet is already believed to bebandwidth constrained, the use of multicasting could be deemeda requirement. The following paper will explore current issueswith deploying IPTV over the Internet, the use of multicast tocombat some of these problems, and the inherent challenges ofpushing multicast based IPTV services over the Internet
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