104,478 research outputs found

    FOMC learning and productivity growth (1985-2003): a reading of the record

    Get PDF
    The increasingly rapid productivity growth that began in the 1990s was the defining economic event of the decade and a major topic of debate among Federal Reserve policymakers. A key aspect of the debate was the contrast between information contained in aggregate data, which initially suggested little productivity gain, and anecdotal firm-level evidence, which hinted at the productivity acceleration. The authors revisit this debate from the actual FOMC transcripts. Their study illustrates the process by which policymakers filter incoming data to identify changes in underlying fundamental trends.Monetary policy

    Computation of three-dimensional nozzle-exhaust flow fields with the GIM code

    Get PDF
    A methodology is introduced for constructing numerical analogs of the partial differential equations of continuum mechanics. A general formulation is provided which permits classical finite element and many of the finite difference methods to be derived directly. The approach, termed the General Interpolants Method (GIM), can combined the best features of finite element and finite difference methods. A quasi-variational procedure is used to formulate the element equations, to introduce boundary conditions into the method and to provide a natural assembly sequence. A derivation is given in terms of general interpolation functions from this procedure. Example computations for transonic and supersonic flows in two and three dimensions are given to illustrate the utility of GIM. A three-dimensional nozzle-exhaust flow field is solved including interaction with the freestream and a coupled treatment of the shear layer. Potential applications of the GIM code to a variety of computational fluid dynamics problems is then discussed in terms of existing capability or by extension of the methodology

    Advanced fiber placement of composite fuselage structures

    Get PDF
    The Hercules/NASA Advanced Composite Technology (ACT) program will demonstrate the low cost potential of the automated fiber placement process. The Hercules fiber placement machine was developed for cost effective production of composite aircraft structures. The process uses a low cost prepreg tow material form and achieves equivalent laminate properties to structures fabricated with prepreg tape layup. Fiber placement demonstrations planned for the Hercules/NASA program include fabrication of stiffened test panels which represent crown, keel, and window belt segments of a typical transport aircraft fuselage

    The 1990s acceleration in labor productivity: causes and measurement

    Get PDF
    The acceleration of labor productivity growth that began during the mid-1990s is the defining economic event of the past decade. A consensus has arisen among economists that the acceleration was caused by technological innovations that decreased the quality-adjusted prices of semiconductors and related information and communications technology (ICT) products, including digital computers. In sharp contrast to the previous 20 years, services-producing sectors-heavy users of ICT products-led the productivity increase, besting even a robust manufacturing sector. In this article, the authors survey the performance of the services-producing and goods-producing sectors and examine revisions to aggregate labor productivity data of the type commonly discussed by policymakers. The revisions, at times, were large enough to reverse preliminary conclusions regarding productivity growth slowdowns and accelerations. The unanticipated acceleration in the services sector and the large size of revisions to aggregate data combine to shed light on why economists were slow to recognize the productivity acceleration.Labor productivity

    Finite difference grid generation by multivariate blending function interpolation

    Get PDF
    The General Interpolants Method (GIM) code which solves the multidimensional Navier-Stokes equations for arbitrary geometric domains is described. The geometry module in the GIM code generates two and three dimensional grids over specified flow regimes, establishes boundary condition information and computes finite difference analogs for use in the GIM code numerical solution module. The technique can be classified as an algebraic equation approach. The geometry package uses multivariate blending function interpolation of vector-values functions which define the shapes of the edges and surfaces bounding the flow domain. By employing blending functions which conform to the cardinality conditions the flow domain may be mapped onto a unit square (2-D) or unit cube (3-D), thus producing an intrinsic coordinate system for the region of interest. The intrinsic coordinate system facilitates grid spacing control to allow for optimum distribution of nodes in the flow domain

    How does the FOMC learn about economic revolutions? evidence from the New Economy Era, 1994-2001

    Get PDF
    Forecasting is a daunting challenge for business economists and policymakers, often made more difficult by pervasive uncertainty. No such uncertainty is more difficult than projecting the reaction of policymakers to major shifts in the economy. We explore the process by which the FOMC came to recognize, and react to, the productivity acceleration of the 1990s. Initial impressions were formed importantly by anecdotal evidence. Then, policymakers—and chiefly Alan Greenspan—came to mistrust the data and the forecasts. Eventually, revisions to published data confirmed initial impressions. Our main conclusion is that the productivity-driven positive supply side shocks of the 1990s were initially viewed favorably. However, over time they came to be viewed as posing a threat to the economy, chiefly through unsustainable increases in aggregate demand growth that threatened to increase inflation pressures. Perhaps nothing so complicates business planning and forecasting as policymakers who initially embrace an unanticipated shift and, later, come to abhor the same shift.Federal Open Market Committee ; Financial crises ; Productivity

    Baffling of fluid sloshing in cylindrical tanks Final report

    Get PDF
    Annular baffle for damping liquid oscillations in partially filled cylindrical tan

    Productivity measurement and monetary policymaking during the 1990s

    Get PDF
    The acceleration of productivity growth during the latter half of the 1990s was both the defining economic event of the decade and a major topic of debate among Federal Reserve policymakers. A key aspect of the debate was the conflict between incoming aggregate data, which initially suggested little productivity gain, and anecdotal firm-level evidence which hinted at an acceleration. Some FOMC members feared an overheating economy and higher inflation; others, including the Chairman, argued that revolutionary increases in productivity were occurring and the Committee should not prematurely forgo significant future gains in real income by tightening policy. We review the difficulty of measuring productivity during periods of rapid quality change, the large magnitude of subsequent data revisions during the 1990s, and, from FOMC transcripts, the contemporary monetary policy debate within the FOMC as the decade*s data evolved.Monetary policy ; Production (Economic theory)

    Investigation of parabolic computational techniques for internal high-speed viscous flows

    Get PDF
    A feasibility study was conducted to assess the applicability of an existing parabolic analysis (ADD-Axisymmetric Diffuser Duct), developed previously for subsonic viscous internal flows, to mixed supersonic/subsonic flows with heat addition simulating a SCRAMJET combustor. A study was conducted with the ADD code modified to include additional convection effects in the normal momentum equation when supersonic expansion and compression waves were present. It is concluded from the present study that for the class of problems where strong viscous/inviscid interactions are present a global iteration procedure is required
    corecore