The parameters of non-uniform and uniform quantizers up to ten bits of quantization, optimum for a Gaussian input probability and for the magnitude-error distortion criterion are computed. Optimum quantizers must be understood as quantizers with minimum distortion. The numerical method used for the optimization converges relatively rapidly. The comparison between optimum non-uniform quantizers and optimum uniform quantizers is made.

Topics: NASA Technical Reports Server (NTRS), ERROR ANALYSIS, NORMAL DENSITY FUNCTIONS, OPTIMIZATION,...

To study the nonlinear physics of inhomogeneous turbulent shear flow, the unaveraged Navier-Stokes equations are solved numerically. For initial conditions a three-dimensional cosine velocity fluctuation and a mean-velocity profile with a step are used. Although the initial conditions are nonrandom. The flow soon becomes turbulent. Concentrated turbulent energy develops near the plane where the mean velocity gradient is initially infinite. The terms in the one-point correlation equation for...

Topics: NASA Technical Reports Server (NTRS), NAVIER-STOKES EQUATION, SHEAR FLOW, SHEAR LAYERS, TURBULENCE,...

152
152

Jun 1, 2010
06/10

by
Pogorelov, V. I

texts

######
eye 152

######
favorite 0

######
comment 0

Variance of electron density fluctuations in ionization zones of aurorae - root-mean-square error of scattering cross section formulas

Topics: AURORAL ZONES, ELECTRON DENSITY, ROOT-MEAN-SQUARE ERROR, SCATTERING CROSS SECTION, AURORAS,...

292
292

Jun 2, 2011
06/11

by
Brooks, Ronald L.; Lee, Jeffre

texts

######
eye 292

######
favorite 0

######
comment 0

This document provides an overview'of software development activities and the resulting products and procedures developed by the TOPEX Software Development Team (SWDT) at Wallops Flight Facility, in support of the WFF TOPEX Engineering Assessment and Verification efforts.

Topics: OCEAN DATA ACQUISITIONS SYSTEMS, INTERPOLATION, OCEAN MODELS, ROOT-MEAN-SQUARE ERRORS, DATA...

The root-mean-square error performance measure is used to compare the relative performance of several widely known source coding algorithms with the RM2 image data compression system. The results demonstrate that RM2 has a uniformly significant performance advantage.

Topics: NASA Technical Reports Server (NTRS), DATA COMPRESSION, ERROR ANALYSIS, OPTICAL DATA PROCESSING,...

A procedure is described for determining the noise equivalent difference temperature for infrared electro-optical instruments. The instrumentation required, proper measurements, and methods of calculation are included.

Topics: NASA Technical Reports Server (NTRS), AMBIENT TEMPERATURE, ELECTROMAGNETIC NOISE, INFRARED...

The dual-pump coherent anti-Stokes Raman spectroscopy (CARS) method is used to measure temperature and the relative species densities of N2, O2 and H2 in two experiments. Average values and root-mean-square (RMS) deviations are determined. Mean temperature measurements in a furnace containing air between 300 and 1800 K agreed with thermocouple measurements within 26 K on average, while mean mole fractions agree to within 1.6 % of the expected value. The temperature measurement standard...

Topics: NASA Technical Reports Server (NTRS), HYDROGEN, NITROGEN, OXYGEN, ROOT-MEAN-SQUARE ERRORS,...

A multistage estimator is provided for the parameters of a received carrier signal possibly phase-modulated by unknown data and experiencing very high Doppler, Doppler rate, etc., as may arise, for example, in the case of Global Positioning Systems (GPS) where the signal parameters are directly related to the position, velocity and jerk of the GPS ground-based receiver. In a two-stage embodiment of the more general multistage scheme, the first stage, selected to be a modified least squares...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ERROR SIGNALS, ESTIMATING, GLOBAL POSITIONING...

The results are reported of research into the effects on system operation of signal quantization in a digital control system. The investigation considered digital controllers (filters) operating in floating-point arithmetic in either open-loop or closed-loop systems. An error analysis technique is developed, and is implemented by a digital computer program that is based on a digital simulation of the system. As an output the program gives the programing form required for minimum system...

Topics: NASA Technical Reports Server (NTRS), DIGITAL FILTERS, ERROR ANALYSIS, FLOATING POINT ARITHMETIC,...

A computer program is described that performs a statistical multiple-decision procedure called chain pooling. It uses a number of mean squares assigned to error variance that is conditioned on the relative magnitudes of the mean squares. The model selection is done according to user-specified levels of type 1 or type 2 error probabilities.

Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, FACTORIAL DESIGN, MATHEMATICAL MODELS,...

A nonlinear modeling technique was used to characterize response surfaces for non-dimensional longitudinal aerodynamic force and moment coefficients, based on wind tunnel data from a commercial jet transport model. Data were collected using two experimental procedures - one based on modem design of experiments (MDOE), and one using a classical one factor at a time (OFAT) approach. The nonlinear modeling technique used multivariate orthogonal functions generated from the independent variable...

Topics: NASA Technical Reports Server (NTRS), MULTIVARIATE STATISTICAL ANALYSIS, ORTHOGONAL FUNCTIONS,...

Inaccuracies in the length of members and the diameters of joints of large truss reflector backup structures may produce unacceptable levels of surface distortion and member forces. However, if the member lengths and joint diameters can be measured accurately it is possible to configure the members and joints so that root-mean-square (rms) surface error and/or rms member forces is minimized. Following Greene and Haftka (1989) it is assumed that the force vector f is linearly proportional to the...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ANNEALING, COMBINATORIAL ANALYSIS, OPERATIONS...

Nonlinear filters are often very computationally expensive and usually not suitable for real-time applications. Real-time navigation algorithms are typically based on linear estimators, such as the extended Kalman filter (EKF) and, to a much lesser extent, the unscented Kalman filter. The Iterated Kalman filter (IKF) and the Recursive Update Filter (RUF) are two algorithms that reduce the consequences of the linearization assumption of the EKF by performing N updates for each new measurement,...

Topics: NASA Technical Reports Server (NTRS), KALMAN FILTERS, NONLINEAR FILTERS, STATISTICAL ANALYSIS,...

The trajectory of an orbiting spacecraft is determined from an orbit determination program. Two inputs to this program, among others, are the range and range rate relative to some known location. The arithmetic and measurement errors in the determinations of the range, range rate, and range differences were identified and evaluated. These uncertainties are tabulated for one way and two way systems. A comparison of the measurement error contributions illustrate the predominance of thermal noise...

Topics: NASA Technical Reports Server (NTRS), RANGEFINDING, TDR SATELLITES, VERY HIGH FREQUENCIES,...

A control law synthesis methodology for multifunctional active control system to satisfy root-mean-square load and response constraints as well as to meet stability robustness requirements at plant input and output was developed. Modern control theory, singular value analysis and optimization techniques were utilized. All stability and response derivative expressions were derived analytically for sensitivity study. The software is incorporated as an update to the AB/LAD general control design...

Topics: NASA Technical Reports Server (NTRS), CONTROL THEORY, GAUSS EQUATION, QUADRATIC PROGRAMMING, BLOCK...

A new algorithm has been developed for the estimation of tropospheric microwave path delays from water vapor radiometer (WVR) data, which does not require site and weather dependent empirical parameters to produce high accuracy. Instead of taking the conventional linear approach, the new algorithm first uses the observables with an emission model to determine an approximate form of the vertical water vapor distribution which is then explicitly integrated to estimate wet path delays, in a second...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, DEEP SPACE NETWORK, DELAY, ESTIMATING, MICROWAVE...

Acceleration due to earth's gravity causes buoyancy driven convection and sedimentation in solutions. In addition. pressure gradients occur as a function of the height within a liquid column. Hence gravity effects both equilbria conditions and phase transitions as a result of hydrostatic pressure gradients. The affect of gravity on the rate of heat and man transfer in solutal processes can be particularly important in polymer processing due to the high sensitivity of polymeric materials to...

Topics: NASA Technical Reports Server (NTRS), MICROGRAVITY, EARTH GRAVITATION, SPACE FLIGHT, ACCELERATION...

229
229

Jun 11, 2011
06/11

by
Chao, Benjamin F.; Cox, Christopher M

texts

######
eye 229

######
favorite 0

######
comment 0

Satellite laser-ranging (SLR) has been observing the tiny variations in Earth s global gravity for over 2 decades. The oblateness of the Earth's gravity field, J2, has been observed to undergo a secular decrease of J2 due mainly to the post-glacial rebound of the mantle. Sometime around 1998 this trend reversed quite suddenly. This reversal persisted until 2001, at which point the atmosphere-corrected time series appears to have reversed yet again towards normal. This anomaly signifies a large...

Topics: MAGNETOSPHERES, ECCENTRIC ORBITS, SPACECRAFT TRAJECTORIES, MONTE CARLO METHOD, APOGEES, SPACECRAFT...

The 45th Weather Squadron Launch Weather Officers use the 12-km resolution North American Mesoscale model (MesoNAM) forecasts to support launch weather operations. In Phase I, the performance of the model at KSC/CCAFS was measured objectively by conducting a detailed statistical analysis of model output compared to observed values. The objective analysis compared the MesoNAM forecast winds, temperature, and dew point to the observed values from the sensors in the KSC/CCAFS wind tower network....

Topics: NASA Technical Reports Server (NTRS), MESOMETEOROLOGY, MESOSCALE PHENOMENA, SPACE SHUTTLES,...

The purpose of this workshop was to reinforce the working partnership between centers who are actively involved in global aerosol forecasting, and to discuss issues related to forecast verification. Participants included representatives from operational centers with global aerosol forecasting requirements, a panel of experts on Numerical Weather Prediction and Air Quality forecast verification, data providers, and several observers from the research community. The presentations centered on a...

Topics: NASA Technical Reports Server (NTRS), AEROSOLS, AIR QUALITY, NUMERICAL WEATHER FORECASTING,...

The maximum root-mean-square response of a square clamped plate, subjected to a stationary random excitation, was determined both theoretically and empirically. For the tests, a 40 x 40 x 1/4 aluminum sheet was milled out to provide a thin waffle plate with 9 panels. The plate was acoustically excited, with the frequency range limited between 25 Hz and 500 Hz. The root-mean-square power of the random excitations, 149 decibels, was nearly constant for all natural frequencies of the plate system....

Topics: NASA Technical Reports Server (NTRS), EXCITATION, METAL PLATES, RANDOM PROCESSES, ROOT-MEAN-SQUARE...

Inflatable aperture reflector antennas are an emerging technology that NASA is investigating for potential uses in science and exploration missions. As inflatable aperture antennas have not been proven fully qualified for space missions, they must be characterized properly so that the behavior of the antennas can be known in advance. To properly characterize the inflatable aperture antenna, testing must be performed in a relevant environment, such as a vacuum chamber. Since the capability of...

Topics: NASA Technical Reports Server (NTRS), REFLECTOR ANTENNAS, VACUUM CHAMBERS, PHOTOGRAMMETRY, LASER...

An experiment was conducted to quantify the effects of changing dynamics on a subject s ability to track a signal in order to eventually model a pilot adapting to changing aircraft dynamics. The data will be used to identify primary aircraft dynamics variables that influence changes in pilot s response and produce a simplified pilot model that incorporates this relationship. Each run incorporated a different set of second-order aircraft dynamics representing short period transfer function pitch...

Topics: NASA Technical Reports Server (NTRS), ATTITUDE (INCLINATION), TRACKING (POSITION), TRANSFER...

The rms magnitude, spectra, and cross correlations for the fluctuations in the beam current, the neutralizer keeper current, and the discharge current and voltage were measured for an 8-cm diameter, dished grid ion thruster for a beam current of 72 milliamps. The ratio of the rms magnitude of the fluctuations to the time-mean neutralizer keeper current was found to depend significantly on the neutralizer time-mean keeper current, the flow rate, and keeper hold diameter. The maxima of the...

Topics: NASA Technical Reports Server (NTRS), ELECTRON BOMBARDMENT, ION BEAMS, PLASMA TURBULENCE, BEAM...

178
178

Jun 2, 2011
06/11

by
Mulligan, Jeffrey B

texts

######
eye 178

######
favorite 0

######
comment 0

Eye movements can provide a wealth of information about how human operators perceive and process visual information. Video-based measurement systems offer considerable advantages over competing approaches for use in applied contexts outside the laboratory: first, they do not require physical contact with the eye, and second, they do not restrict the subject s movement. This research investigates image processing methods in an effort to obtain greater accuracy from video images of the eye....

Topics: AMAZON REGION (SOUTH AMERICA), IN SITU MEASUREMENT, ROOT-MEAN-SQUARE ERRORS, PH, RICHARDSON NUMBER,...

The results of a simulator study conducted to compare and validate various ride quality prediction methods for use in assessing passenger/crew ride comfort within helicopters are presented. Included are results quantifying 35 helicopter pilots discomfort responses to helicopter interior noise and vibration typical of routine flights, assessment of various ride quality metrics including the NASA ride comfort model, and examination of possible criteria approaches. Results of the study indicated...

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT NOISE, HELICOPTERS, PREDICTION ANALYSIS TECHNIQUES,...

Aircraft climb trajectories are difficult to predict, and large errors in these predictions reduce the potential operational benefits of some advanced features for NextGen. The algorithm described in this paper improves climb trajectory prediction accuracy by adjusting trajectory predictions based on observed track data. It utilizes rate-of-climb and airspeed measurements derived from position data to dynamically adjust the aircraft weight modeled for trajectory predictions. In simulations with...

Topics: NASA Technical Reports Server (NTRS), TRAJECTORIES, CLIMBING FLIGHT, ALGORITHMS, ADAPTIVE CONTROL,...

Described here is the application of the microwave holography technique to Deep Space Station (DSS) 13. The project goal of obtaining a rigging angle surface rms error of 0.43 mm or better was met. The Jet Propulsion Laboratory-developed holography algorithms enabled a reduction of the surface error of the DSS-13 antenna from the optically set 0.83 mm axial rms error down to 0.40 mm rms, providing an additional 4.1 dB of performance at 32 GHz.

Topics: NASA Technical Reports Server (NTRS), ANGLES (GEOMETRY), BEAM WAVEGUIDES, MICROWAVE HOLOGRAPHY,...

Surface topography, including the various physical methods of measuring surfaces, and the various lubrication regimes (hydrodynamic, elastohydrodynamic, boundary, and mixed) are discussed. The historical development of elastohydrodynamic lubrication is outlined. The major accomplishments in four periods, the pre-1950's, the 1950's, the 1960's, and the 1970's are presented.

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LUBRICATION, ELASTOHYDRODYNAMICS, FLUID FILMS,...

This report provides results of an independent assessment of the geopositional accuracy of the Earth Satellite (EarthSat) Corporation's GeoCover, Orthorectified Landsat Thematic Mapper (TM) imagery over Northeast Asia. This imagery was purchased through NASA's Earth Science Enterprise (ESE) Scientific Data Purchase (SDP) program.

Topics: NASA Technical Reports Server (NTRS), ASIA, EARTH SCIENCES, LANDSAT SATELLITES, SATELLITE IMAGERY,...

The Applied Meteorology Unit (AMU) conducted a year-long evaluation of NCEP's 29-km mesoscale Eta (meso-eta) weather prediction model in order to identify added value to forecast operations in support of the United States space program. The evaluation was stratified over warm and cool seasons and considered both objective and subjective verification methodologies. Objective verification results generally indicate that meso-eta model point forecasts at selected stations exhibit minimal error...

Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC MODELS, WEATHER FORECASTING, SPACE PROGRAMS,...

The simulation of runoff from a Himalayan Glacier basin using an Artificial Neural Network (ANN) is presented. The performance of the ANN model is found to be superior to the Energy Balance Model and the Multiple Regression model. The RMS Error is used as the figure of merit for judging the performance of the three models, and the RMS Error for the ANN model is the latest of the three models. The ANN is faster in learning and exhibits excellent system generalization characteristics.

Topics: NASA Technical Reports Server (NTRS), COMPUTERIZED SIMULATION, ERROR ANALYSIS, GLACIERS, HYDROLOGY...

An active controller was used to help train naive subjects involved in a compensatory tracking task. The controller is called active in this context because it moves the subject's hand in a direction to improve tracking. It is of interest here to question whether the active controller helps the subject to learn a task more rapidly than the passive controller. Six subjects, inexperienced to compensatory tracking, were run to asymptote root mean square error tracking levels with an active...

Topics: NASA Technical Reports Server (NTRS), ACTIVE CONTROL, CONTROL STICKS, LEARNING, REACTION TIME, TASK...

Phase retrieval was applied to under-sampled data from a thermal infrared imaging system to estimate defocus across the field of view (FOV). We compare phase retrieval estimated values to those obtained using an independent technique.

Topics: NASA Technical Reports Server (NTRS), INFRARED DETECTORS, IMAGING TECHNIQUES, OPTICS, INFRARED...

The Williams type model, developed similarly to previous models of C.V.D. Williams, uses monthly temperature and precipitation data as well as soil and topological variables to predict the yield of the spring wheat crop. The models are statistically developed using the regression technique. Eight model characteristics are examined in the evaluation of the model. Evaluation is at the crop reporting district level, the state level and for the entire region. A ten year bootstrap test was the basis...

Topics: NASA Technical Reports Server (NTRS), AGRISTARS PROJECT, CROP INVENTORIES, MATHEMATICAL MODELS,...

In part I of this paper, the United States (US) radiosonde temperature data are shown to have significant and unexplained inhomogeneities in the mid-troposphere. This part discusses the differences between observations taken at 0 and 12 UTC especially in the stratosphere by the Vaisala RS80 radiosondes that are integrated within the National Weather Service's (NWS) Micro-ART system. The results show that there is a large maxima in the horizontal distribution of the monthly means of the 0/12 UTC...

Topics: NASA Technical Reports Server (NTRS), DISCONTINUITY, RADIOSONDES, TEMPERATURE PROFILES,...

137
137

May 27, 2011
05/11

by
Hansen, Patricia A.; Hughes, David W.; Montt, Kristina M.; Triolo, Jack J

texts

######
eye 137

######
favorite 0

######
comment 0

Maintaining contamination certification of multi-mission flight hardware is an innovative approach to controlling mission costs. Methods for assessing ground induced degradation between missions have been employed by the Hubble Space Telescope (HST) Project for the multi-mission (servicing) hardware. By maintaining the cleanliness of the hardware between missions, and by controlling the materials added to the hardware during modification and refurbishment both project funding for contamination...

Topics: MAGNETIC FIELDS, SOLAR CONVECTION (ASTRONOMY), ROOT-MEAN-SQUARE ERRORS, AZIMUTH, MAGNETIC...

Important properties of derivative (difference) filters using the discrete Fourier transform are investigated. The filters are designed using the derivative theorem of Fourier analysis. Because physical data are generally degraded by noise, the derivative filter is modified to diminish the effects of the noise, especially the noise amplification which normally occurs while differencing. The basis for these modifications is the reduction of those Fourier components for which the noise most...

Topics: NASA Technical Reports Server (NTRS), DERIVATION, DIFFERENCES, FOURIER TRANSFORMATION, LOW PASS...

AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an rms error of 1 K, and layer...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ATMOSPHERIC SOUNDING, CLOUD COVER, ERROR...

The advantages of using higher order, interpolatory basis functions are examined in the analysis of transverse electric (TE) plane wave scattering by homogeneous, dielectric cylinders. A boundary-element/finite-element (BEM/FEM) hybrid formulation is employed in which the interior dielectric region is modeled with the vector Helmholtz equation, and a radiation boundary condition is supplied by an Electric Field Integral Equation (EFIE). An efficient method of handling the singular self-term...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, BOUNDARY CONDITIONS, DIELECTRICS, FINITE ELEMENT...

Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF...

Topics: NASA Technical Reports Server (NTRS), DEFECTS, ELECTROCARDIOGRAPHY, HIGH FREQUENCIES, IMAGING...

A two-component Point Doppler Velocimeter (PDV) system has been improved through the use of vapor-limited iodine cells that have responses that are insensitive to temperature variations. Two-component PDV velocity measurements have been obtained for a 1 inch diameter uniform circular jet flow at a nominal exit velocity of 60 m/sec, corresponding to a Reynolds number of 100,000. Similar data have also been obtained for an annular jet and a swirling jet, These PDV data runs have been duplicated...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYERS, VELOCITY MEASUREMENT, LASER DOPPLER...

229
229

Jun 9, 2011
06/11

by
Diskin, Glenn S.; Lempert, Walter R.; Miles, Richard B

texts

######
eye 229

######
favorite 0

######
comment 0

A three level model has been developed for the analysis of Schumann-Runge band (B(sup 3)Sigma(sup -)(sub u ) (- X(sup 3)Sigma(sup -)(sub g)) laser-induced fluorescence of molecular oxygen, O2. Such a model is required due to the severe lower state depletion which can occur when transitions having relatively large absorption cross-sections are excited. Such transitions are often utilized via ArF or KrF excimer or dye-laser excitation in high temperature environments. The rapid predissociation of...

Topics: TROPOSPHERE, CORRELATION COEFFICIENTS, SOUTHEAST ASIA, ANNUAL VARIATIONS, BIOMASS BURNING,...

An Algorithm is suggested for defining the coordinates of X-ray and Gamma Ray radiation sources by measuring the time lag of the transmission of radiation flares from various points of space in which spacecraft are located. Instances are cited where the 2-x, 3-x and 4x spacecraft are used.

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ASTRONOMICAL COORDINATES, GAMMA RAY ASTRONOMY,...

The impact of more timely and accurate weather data on airline flight planning with the emphasis on fuel savings is studied. This volume of the report discusses the results of Task 3 of the four major tasks included in the study. Task 3 compares flight plans developed on the Suitland forecast with actual data observed by the aircraft (and averaged over 10 degree segments). The results show that the average difference between the forecast and observed wind speed is 9 kts. without considering...

Topics: NASA Technical Reports Server (NTRS), AVIATION METEOROLOGY, ENERGY CONSERVATION, FLIGHT PATHS, FUEL...

The objective was to predict the inherent turbulence response characteristics of candidate wind shear warning system concepts and to assess the potential for nuisance alerts. Information on the detection system and associated signal processing, physical and mathematical models, wind shear factor root mean square turbulence response and the standard deviation of the wind shear factor due to turbulence is given in vugraph form.

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT HAZARDS, ATMOSPHERIC TURBULENCE, FALSE ALARMS,...

230
230

Jun 13, 2011
06/11

by
Poivey, C.; Hornback, V.; Song, J.; Tung, J.; Mirabedini, M; Kim, H.; Vilchis, M.; Forney, J.; Phan, A.; LaBel, K.; Saigusa, R.; Finlinson, R.; Sukharnov, A.

texts

######
eye 230

######
favorite 0

######
comment 0

This viewgraph presentation reviews the tests of a modified commercial CMOS chip for operation in radiation environments. The presentation has pictures of the chip, and charts of the test results.

Topics: ACOUSTIC FATIGUE, DEGREES OF FREEDOM, DISPLACEMENT, STRESS MEASUREMENT, ROOT-MEAN-SQUARE ERRORS,...

The CEAS yield model is based upon multiple regression analysis at the CRD and state levels. For the historical time series, yield is regressed on a set of variables derived from monthly mean temperature and monthly precipitation. Technological trend is represented by piecewise linear and/or quadriatic functions of year. Indicators of yield reliability obtained from a ten-year bootstrap test (1970-79) demonstrated that biases are small and performance as indicated by the root mean square errors...

Topics: NASA Technical Reports Server (NTRS), AGRISTARS PROJECT, BARLEY, CROP INVENTORIES, MATHEMATICAL...

263
263

Jul 26, 2010
07/10

by
Schochet, Steven; Tadmor, Eita

texts

######
eye 263

######
favorite 0

######
comment 0

Rosenau has recently proposed a regularized version of the Chapman-Enskog expansion of hydrodynamics. This regularized expansion resembles the usual Navier-Stokes viscosity terms at law wave-numbers, but unlike the latter, it has the advantage of being a bounded macroscopic approximation to the linearized collision operator. The behavior of Rosenau regularization of the Chapman-Enskog expansion (RCE) is studied in the context of scalar conservation laws. It is shown that thie RCE model retains...

Topics: LARGE SPACE STRUCTURES, FINITE ELEMENT METHOD, GRAPHITE-EPOXY COMPOSITES, METAL JOINTS, ORBITAL...

A principal-component based radiative transfer model (PCRTM) is developed for simulating the infrared spectral radiance at the top of the atmosphere (TOA). The PCRTM approach removes the redundancy in radiative transfer calculation in high resolution infrared spectra, and saves significant amount of computational time with great accuracy. In PCRTM, both ice and water clouds are treated as effective transmissivity and reflectivity stored in a pre-calculated lookup tables. These quantities are...

Topics: NASA Technical Reports Server (NTRS), CLOUD COVER, INFRARED SPECTRA, RADIATIVE TRANSFER,...