37,081 research outputs found

    Evaluation of the East Bay Municipal Utility District's Pilot of WaterSmart Home Water Reports

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    This report presents the results of an independent evaluation of the East Bay Municipal Utility District's (EBMUD) year-long pilot project (Pilot) of WaterSmart Software's Home Water Reports (HWRs) service.The Pilot was intended to address three primary questions:First, would an SNB efficiency program like WaterSmart result in measurable reductionsin household water use?Second, would it increase rates of participation in other EBMUD conservation programs? Third, would it increase household knowledge and awareness of water consumption andways to use water more efficiently

    Theoretical investigation of the force and dynamically coupled torsional-axial-lateral dynamic response of eared rotors

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    Difficulties in solution methodology to be used to deal with the potentially higher nonlinear rotor equations when dynamic coupling is included. A solution methodology is selected to solve the nonlinear differential equations. The selected method was verified to give good results even at large nonlinearity levels. The transfer matrix methodology is extended to the solution of nonlinear problems

    A study of the effects of varying the sampling for a simplified version of the Saturn V/S-1C Final report, 15 May 1968 - 31 Aug. 1969

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    Bending frequency filtering through adaptive sampling for Saturn 5 stage 1C desig

    Compensator improvement for multivariable control systems

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    A theory and the associated numerical technique are developed for an iterative design improvement of the compensation for linear, time-invariant control systems with multiple inputs and multiple outputs. A strict constraint algorithm is used in obtaining a solution of the specified constraints of the control design. The result of the research effort is the multiple input, multiple output Compensator Improvement Program (CIP). The objective of the Compensator Improvement Program is to modify in an iterative manner the free parameters of the dynamic compensation matrix so that the system satisfies frequency domain specifications. In this exposition, the underlying principles of the multivariable CIP algorithm are presented and the practical utility of the program is illustrated with space vehicle related examples

    Laboratory calibration of AAFE radiometer/scatterometer (RADSCAT)

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    A brief description of the electrical and mechanical instrument configuration, followed by an extensive discussion of laboratory tests and results are contained herein. This information is required to provide parameters for data reduction, and a basis for analysis of the measurement errors in data taken with this instrument

    An innovative approach to compensator design

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    The design is considered of a computer-aided-compensator for a control system from a frequency domain point of view. The design technique developed is based on describing the open loop frequency response by n discrete frequency points which result in n functions of the compensator coefficients. Several of these functions are chosen so that the system specifications are properly portrayed; then mathematical programming is used to improve all of these functions which have values below minimum standards. To do this, several definitions in regard to measuring the performance of a system in the frequency domain are given, e.g., relative stability, relative attenuation, proper phasing, etc. Next, theorems which govern the number of compensator coefficients necessary to make improvements in a certain number of functions are proved. After this a mathematical programming tool for aiding in the solution of the problem is developed. This tool is called the constraint improvement algorithm. Then for applying the constraint improvement algorithm generalized, gradients for the constraints are derived. Finally, the necessary theory is incorporated in a Computer program called CIP (compensator Improvement Program). The practical usefulness of CIP is demonstrated by two large system examples

    Flight measurement and analysis of AAFE RADSCAT wind speed signature of the ocean

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    The advanced aerospace flight experiment radiometer scatterometer (AAFE RADSCAT) which was developed as a research tool to evaluate the use of microwave frequency remote sensors to provide wind speed information at the ocean surface is discussed. The AAFE RADSCAT helped establish the feasibility of the satellite scatterometer for measuring both wind speed and direction. The most important function of the AAFE RADSCAT was to provide a data base of ocean normalized radar cross section (NRCS) measurements as a function of surface wind vector at 13.9 GHz. The NRCS measurements over a wide parametric range of incidence angles, azimuth angles, and winds were obtained in a series of RADSCAT aircraft missions. The obtained data base was used to model the relationship between k sub u band radar signature and ocean surface wind vector. The models developed therefrom are compared with those used for inversion of the SEASAT-A satellite scatterometer (SASS) radar measurements to wind speeds

    Payroll employment data: measuring the effects of annual benchmark revisions

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    During the recovery from the 2001 recession, the business press and economic analysts used payroll employment data released monthly by the U.S. Bureau of Labor Statistics (BLS) as evidence of protracted weakness in the labor market. But using these monthly releases for this type of analysis can be premature and potentially misleading. The initial BLS releases can differ substantially from payroll employment data that are revised to incorporate information from less timely but more complete sources. ; This article highlights the historical revisions to the aggregate nonfarm payroll employment series. Examining both monthly survey-based revisions and the more extensive annual benchmark revisions, the authors focus specifically on how the sequence of data revisions modifies payroll employment estimates from their initial release. The graphs in the article display the magnitude and direction of each revision from the initial estimate for a particular month to its currently published value, demonstrating that the largest portion of enduring change for the estimates occurs in the benchmark revisions. ; The authors then investigate empirically whether these revisions contain information that can be exploited to anticipate future revisions. The analysis shows that previous benchmark data revisions are useful for explaining the variation in subsequent payroll employment benchmark data. Such information, the authors note, could prove useful for further research aimed at modeling better real-time estimates of employment conditions.Employment (Economic theory)

    An operational satellite scatterometer for wind vector measurements over the ocean

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    Performance requirements and design characteristics of a microwave scatterometer wind sensor for measuring surface winds over the oceans on a global basis are described. Scatterometer specifications are developed from user requirements of wind vector measurement range and accuracy, swath width, resolution cell size and measurement grid spacing. A detailed analysis is performed for a baseline fan-beam scatterometer design, and its performance capabilities for meeting the SeaSat-A user requirements. Various modes of operation are discussed which will allow the resolution of questions concerning the effects of sea state on the scatterometer wind sensing ability and to verify design boundaries of the instrument
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