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At least 577 records · Page 32

Core Model Proposal 401: Ukraine as an independent region in GCAM

The goal of this core model proposal (CMP) is to break out Ukraine from the Europe_Eastern region. This work aims to establish Ukraine as an independent region in the GCAM core (region 14) while moving Belarus and Moldova to region 15 (Europe_Non_EU). We have: 1) Updated several mappings to recode region 14 (formerly Europe_Eastern) as Ukraine and moved Belarus and Moldova to region 15 (Europe_Non_EU); 2) Updated several assumptions in the raw data files which provide information by region to reframe Ukraine as the 14th region, including coefficients, base year values, share weight interpolation values and rules, pipeline networks for gas trade, elasticities, shares, etc. 3) Changed documentation and in-code comments at several places referring to fixed 32 regions in GCAM to indicate that GCAM can have any number of regions; 4) Updated code base in gcamdata to dynamically process data for Ukraine given special cases.

Global Change Analysis Model (GCAM)↗

Infrared Cloud Imager Instrument Intercomparison Report

The Infrared Cloud Imager Instrument Intercomparison was a guest instrument deployment by NWB Sensors to the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) User Facility observatory on the Southern Great Plains (SGP) between May 18 and December 12, 2023. NWB Sensors is a company that has developed a commercially available infrared cloud imager (ICI). The ICI provides radiometrically calibrated, full-sky images of the downwelling infrared radiance in the 7.3-14 µm band. In addition, it provides cloud radiance as the residual between the observed radiance and the modeled cloud-free radiance as well as derived cloud products. The instrument is used in applications that require consistent detection of clouds across day and night. For more information, consult the instrument's webpage. The primary goal of the deployment was to validate the radiometric accuracy of the ICI. The ICI uses a proprietary calibration method to convert the raw data from its infrared camera into downwelling radiance. Unlike similar instruments, the system does not have an onboard blackbody calibration standard. Instead, NWB Sensors characterizes each ICI camera individually in an environmental chamber while looking at a blackbody standard. The resulting (proprietary) calibration is used operationally in the instrument and has been demonstrated to be stable over long periods. To validate the radiometric products from the ICI, an intercomparison between the ICI data products and those from ARM’s atmospheric emitted radiance interferometer (AERI) was made. The AERI is a best-in-class instrument for measuring downwelling infrared radiance (Gero et al. 2025). A weighted integration of the AERI’s spectral radiances across the ICI’s camera response was performed. The resulting radiance (herein called the AERI radiance) was directly compared to the zenith radiance concurrently observed by the ICI. The results of these comparisons are reported in the next section of this report.

54 ENVIRONMENTAL SCIENCES↗

DeepDiagnostics: A Software Package for Streamlined Posterior Evaluation

Automated prediction techniques like simulation-based inference (SBI) are important tasks for science experiments that produce large amounts of complex, raw data. However, their development remains in its early stages because the uncertainties of these techniques lack sufficient trustworthiness and interpretability. Packages for SBI provide a growing set of diagnostics; however, the software requirements are substantial, as they are tied to the inference technology itself, and the APIs lack adaptability. We introduce the DeepDiagnostics package for diagnosing posteriors from analytic likelihood-based methods and SBI methods, such as neural posterior estimation. DeepDiagnostics produces a comprehensive set of high-quality visualizations and metrics in a highly accessible, easy-to-use, and flexible package. We address all of these goals by providing a command-line inference tool and a Python API that is controlled through a configuration file. The package includes common diagnostics, such as parity plots, corner (covariance) plots, simulation-based calibration (SBC) diagnostics (including posterior coverage and rank histograms), Lemos et al. s PQMass and TARP, Masserano et al. s WALDO, Linhart et al. s LC2ST, as well as credible region diagnostics developed by our group.

Voetberg, Maggie [Fermilab]↗

Cloud Doppler Radar

This dataset contains raw data from the UND 94 GHz W-band Cloud Doppler Radar.

17 WIND ENERGY↗

Laser Disdrometer / Daily Standardized Files

This dataset contains raw data from the laser disdrometer at Nantucket. The disdrometer measures droplet size distribution, hydrometer type, and precipitation rate.

17 WIND ENERGY↗

Addressing GPU memory limitations for Graph Neural Networks in High-Energy Physics applications

Introduction Reconstructing low-level particle tracks in neutrino physics can address some of the most fundamental questions about the universe. However, processing petabytes of raw data using deep learning techniques poses a challenging problem in the field of High Energy Physics (HEP). In the Exa.TrkX Project, an illustrative HEP application, preprocessed simulation data is fed into a state-of-art Graph Neural Network (GNN) model, accelerated by GPUs. However, limited GPU memory often leads to Out-of-Memory (OOM) exceptions during training, due to the large size of models and datasets. This problem is exacerbated when deploying models on High-Performance Computing (HPC) systems designed for large-scale applications. Methods We observe a high workload imbalance issue during GNN model training caused by the irregular sizes of input graph samples in HEP datasets, contributing to OOM exceptions. We aim to scale GNNs on HPC systems, by prioritizing workload balance in graph inputs while maintaining model accuracy. Our paper introduces diverse balancing strategies aimed at decreasing the maximum GPU memory footprint and avoiding the OOM exception, across various datasets. Results Our experiments showcase memory reduction of up to 32.14% compared to the baseline. We also demonstrate the proposed strategies can avoid OOM in application. Additionally, we create a distributed multi-GPU implementation using these samplers to demonstrate the scalability of these techniques on the HEP dataset. Discussion By assessing the performance of these strategies as data loading samplers across multiple datasets, we can gauge their effectiveness in both single-GPU and distributed environments. Our experiments, conducted on datasets of varying sizes and across multiple GPUs, broaden the applicability of our work to various GNN applications that handle input datasets with irregular graph sizes.

Lee, Claire Songhyun↗

Challenges in the Use of AI-Driven Non-Destructive Spectroscopic Tools for Rapid Food Analysis

Routine, remote, and process analysis for foodstuffs is gaining attention and can provide more confidence for the food supply chain. A new generation of rapid methods is emerging both in the literature and in industry based on spectroscopy coupled with AI-driven modelling methods. Current published studies using these advanced methods are plagued by weaknesses, including sample size, abuse of advanced modelling techniques, and the process of validation for both the acquisition method and modelling. This paper aims to give a comprehensive overview of the analytical challenges faced in research and industrial settings where screening analysis is performed while providing practical solutions in the form of guidelines for a range of scenarios. After extended literature analysis, we conclude that there is no easy way to enhance the accuracy of the methods by using state-of-the-art modelling methods and the key remains that capturing good quality raw data from authentic samples in sufficient volume is very important along with robust validation. A comprehensive methodology involving suitable analytical techniques and interpretive modelling methods needs to be considered under a tailored experimental design whenever conducting rapid food analysis.

59 BASIC BIOLOGICAL SCIENCES↗

The application of optimal control techniques to advanced manned missions, volume 2

The hybrid optimization techique for attitude control design is described in detail. The technque is capable of optimizing an n-dimensional adjustable parameter vector, but a 1-dimensional vector is used as an example to explain the procedure. This permits an easier explanation as opposed to a multidimensional case. The procedure used to derive the perturbation equations of motion describing the 6-DOF shuttle ascent phase is presented. These equations were programmed on the EAI 8800 analog computer to describe the perturbations of the shuttle vehicle from a nominal zero lift trajectory due to wind disturbances. Included are the control system equations, trim equations, and wind angle of attack equations. Analog wiring diagrams, raw data and time-varying coefficients, and state variable responses during shuttle ascent are also considered.

Connor, C. L.↗

Excitation of the metastable E(3 Sigma g plus) state of N2 by electron impact

The contribution of the N2(E(3 Sigma g plus)) state to the total metastable excitation function of N2 assessed on the basis of time-of-flight studies of metastable nitrogen molecules. The cross section for electron impact excitation state was determined in the domain of the resonance form threshold (11.87 eV) to an energy of about 13 eV. The maximum value of the cross section was found to be (7.0 + or - 4.0) x 10 to the -18th power sq cm at an energy of 12.2 eV. The measurement was made absolute by using the previously determined yield of the metastable detector, the lifetime of the E state, and by eliminating the energy spread in the electron beam from the raw data. The half-width (FWHM) of the resonance-like excitation function near threshold was found to be about 0.4 eV. No substantial evidence was obtained from the present data for the presence of the nonresonant part of the excitation function for the state studied.

Borst, W. L.↗

Non-planar tests using the wind tunnel free-flight technique.

Results from the first bi-planar wind tunnel free-flight test program designed to investigate the difference between planar and nonplanar dynamic stability are presented. The test provides perhaps the best free-flight angular documentation of arbitrary nonplanar motion yet obtained. Two widely different configurations, a blunt 60-deg cone and a sharp 10-deg half-angle cone, were tested. Comparisons between the angular motion from raw data and the analytical fits indicate a phasing difference. An examination of possible causes discounts experimental errors as an explanation and points strongly toward an inadequacy of the theoretical force model.

Jaffe, P.↗

Ortho- and clinopyroxene compositions in ordinary chondrites and related blander model calculation procedures

Chemical analyses of the orthopyroxene and clinopyroxene compositions in chondrites are reported. Standard microprobe techniques to 15 kilovolts, 0.03 microamperes, and 40 second counting time were employed. Duplicate analyses were conducted on three grains of each opx and cpx together with two different raw data correction methods as checks on analytical precision and correction procedures. Only those analytical summations of between 99.20 and 100.80 weight percent, and cation summations between 3.980 and 4.020 (based on 6 oxygens) were used.

Bunch, T. E.↗

Power spectral density estimation by spline smoothing in the frequency domain

An approach, based on a global averaging procedure, is presented for estimating the power spectrum of a second order stationary zero-mean ergodic stochastic process from a finite length record. This estimate is derived by smoothing, with a cubic smoothing spline, the naive estimate of the spectrum obtained by applying FFT techniques to the raw data. By means of digital computer simulated results, a comparison is made between the features of the present approach and those of more classical techniques of spectral estimation.

Defigueiredo, R. J. P.↗

Some experiments related to L-star instability in rocket motors

The role of solid phase heterogeneity on the low-pressure L-star instability of nonmetallized AP/PBAN propellants is explored. Four particle size distributions are employed in propellants that are otherwise identical. Over one hundred test firings were conducted in the 21/2 in. diameter L-star burner. Pressure time histories in the chamber and color movies of two firings constitute the raw data. An economical firing program was used which enables the interesting range of L-star values to be covered during a single firing (at a set mean pressure), through the variations in the depleting propellant volume. Time-independent combustion, Helmholtz mode, chuff mode, and the pressure-burst phenomena are revealed as the principal signatures. Of these, the Helmholtz mode is found to be the most ordered form of instability.

Kumar, R. N.↗

Power spectral density estimation by spline smoothing in the frequency domain.

An approach, based on a global averaging procedure, is presented for estimating the power spectrum of a second order stationary zero-mean ergodic stochastic process from a finite length record. This estimate is derived by smoothing, with a cubic smoothing spline, the naive estimate of the spectrum obtained by applying Fast Fourier Transform techniques to the raw data. By means of digital computer simulated results, a comparison is made between the features of the present approach and those of more classical techniques of spectral estimation.-

De Figueiredo, R. J. P.↗

Recognition of three dimensional obstacles by an edge detection scheme

The need for an obstacle detection system on the Mars roving vehicle was assumed, and a practical scheme was investigated and simulated. The principal sensing device on this vehicle was taken to be a laser range finder. Both existing and original algorithms, ending with thresholding operations, were used to obtain the outlines of obstacles from the raw data of this laser scan. A theoretical analysis was carried out to show how proper value of threshold may be chosen. Computer simulations considered various mid-range boulders, for which the scheme was quite successful. The extension to other types of obstacles, such as craters, was considered. The special problems of bottom edge detection and scanning procedure are discussed.

Reed, M. A.↗

The efficient identification of relativistic particles by transition radiation

A system of transition radiation detectors has been constructed and exposed to beams of electrons and pions in the energy range of 3 to 15 GeV at SLAC. Transition radiation was generated in a variety of stacks of mylar foils (radiators), and its intensity was detected with 7 multiwire proportional chambers. The raw data demonstrate a good separation between electron and pion induced signals. A more detailed analysis shows that a very efficient identification of individual particles is possible. Typically, a detection efficiency for electrons above 90%, combined with a pion-electron discrimination ratio of .001, has been achieved. Some conclusions with respect to the design of a practical detector for relativistic particles are drawn.

Cherry, M. L.↗

LST and supporting technology

In order to realize the LST objectives of high angular resolution, extended wavelength coverage and faint object detection, the performance of the instruments must be matched to that of the telescope. To insure that adequate technology is available by 1976, an intensive SR & T program has been initiated which builds on previous work and is coordinated with work in other agencies. The primary areas of concern are detectors, on-board computers, and ultraviolet optical components. In the last area grating work is being emphasized. The on-board computer will be necessary to allow pre-processing of raw data and enable detector operation in a pulse counting mode. For detectors, the SEC Vidicon development will be continued but the use of solid-state arrays in the electron bombarded mode and channel plate detectors are being seriously considered. One challenging problem is to provide 2 K cooling to permit ultra-sensitive IR observations to be made.

Sobieski, S.↗

Lunar motion analysis

The results of raw data tapes on lunar motion recorded at McDonald Observatory from January 1 through June 30, 1975 are presented. The direct use of laser pulse shape information in the filtering of return photon data is suggested, together with an extensive revision of the environment record. The absence of archive parameters, including clock epoch offset, atmospheric seeing, and shot-by-shot resolution is noted. Programming problems involving photoelectric occultation observations are also examined.

Mulholland, J. D.↗